fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include <linux/ratelimit.h>
  41 #include <linux/mount.h>
  42 #include <linux/btrfs.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/posix_acl_xattr.h>
  45 #include <linux/uio.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62 #include "qgroup.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 struct btrfs_dio_data {
  70         u64 outstanding_extents;
  71         u64 reserve;
  72         u64 unsubmitted_oe_range_start;
  73         u64 unsubmitted_oe_range_end;
  74 };
  75
  76 static const struct inode_operations btrfs_dir_inode_operations;
  77 static const struct inode_operations btrfs_symlink_inode_operations;
  78 static const struct inode_operations btrfs_dir_ro_inode_operations;
  79 static const struct inode_operations btrfs_special_inode_operations;
  80 static const struct inode_operations btrfs_file_inode_operations;
  81 static const struct address_space_operations btrfs_aops;
  82 static const struct address_space_operations btrfs_symlink_aops;
  83 static const struct file_operations btrfs_dir_file_operations;
  84 static const struct extent_io_ops btrfs_extent_io_ops;
  85
  86 static struct kmem_cache *btrfs_inode_cachep;
  87 struct kmem_cache *btrfs_trans_handle_cachep;
  88 struct kmem_cache *btrfs_transaction_cachep;
  89 struct kmem_cache *btrfs_path_cachep;
  90 struct kmem_cache *btrfs_free_space_cachep;
  91
  92 #define S_SHIFT 12
  93 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  94         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  95         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  96         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  97         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  98         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  99         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 100         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 101 };
 102
 103 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
 104 static int btrfs_truncate(struct inode *inode);
 105 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 106 static noinline int cow_file_range(struct inode *inode,
 107                                    struct page *locked_page,
 108                                    u64 start, u64 end, int *page_started,
 109                                    unsigned long *nr_written, int unlock);
 110 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 111                                            u64 len, u64 orig_start,
 112                                            u64 block_start, u64 block_len,
 113                                            u64 orig_block_len, u64 ram_bytes,
 114                                            int type);
 115
 116 static int btrfs_dirty_inode(struct inode *inode);
 117
 118 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 119 void btrfs_test_inode_set_ops(struct inode *inode)
 120 {
 121         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 122 }
 123 #endif
 124
 125 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 126                                      struct inode *inode,  struct inode *dir,
 127                                      const struct qstr *qstr)
 128 {
 129         int err;
 130
 131         err = btrfs_init_acl(trans, inode, dir);
 132         if (!err)
 133                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 134         return err;
 135 }
 136
 137 /*
 138  * this does all the hard work for inserting an inline extent into
 139  * the btree.  The caller should have done a btrfs_drop_extents so that
 140  * no overlapping inline items exist in the btree
 141  */
 142 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 143                                 struct btrfs_path *path, int extent_inserted,
 144                                 struct btrfs_root *root, struct inode *inode,
 145                                 u64 start, size_t size, size_t compressed_size,
 146                                 int compress_type,
 147                                 struct page **compressed_pages)
 148 {
 149         struct extent_buffer *leaf;
 150         struct page *page = NULL;
 151         char *kaddr;
 152         unsigned long ptr;
 153         struct btrfs_file_extent_item *ei;
 154         int err = 0;
 155         int ret;
 156         size_t cur_size = size;
 157         unsigned long offset;
 158
 159         if (compressed_size && compressed_pages)
 160                 cur_size = compressed_size;
 161
 162         inode_add_bytes(inode, size);
 163
 164         if (!extent_inserted) {
 165                 struct btrfs_key key;
 166                 size_t datasize;
 167
 168                 key.objectid = btrfs_ino(inode);
 169                 key.offset = start;
 170                 key.type = BTRFS_EXTENT_DATA_KEY;
 171
 172                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 173                 path->leave_spinning = 1;
 174                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 175                                               datasize);
 176                 if (ret) {
 177                         err = ret;
 178                         goto fail;
 179                 }
 180         }
 181         leaf = path->nodes[0];
 182         ei = btrfs_item_ptr(leaf, path->slots[0],
 183                             struct btrfs_file_extent_item);
 184         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 185         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 186         btrfs_set_file_extent_encryption(leaf, ei, 0);
 187         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 188         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 189         ptr = btrfs_file_extent_inline_start(ei);
 190
 191         if (compress_type != BTRFS_COMPRESS_NONE) {
 192                 struct page *cpage;
 193                 int i = 0;
 194                 while (compressed_size > 0) {
 195                         cpage = compressed_pages[i];
 196                         cur_size = min_t(unsigned long, compressed_size,
 197                                        PAGE_SIZE);
 198
 199                         kaddr = kmap_atomic(cpage);
 200                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 201                         kunmap_atomic(kaddr);
 202
 203                         i++;
 204                         ptr += cur_size;
 205                         compressed_size -= cur_size;
 206                 }
 207                 btrfs_set_file_extent_compression(leaf, ei,
 208                                                   compress_type);
 209         } else {
 210                 page = find_get_page(inode->i_mapping,
 211                                      start >> PAGE_SHIFT);
 212                 btrfs_set_file_extent_compression(leaf, ei, 0);
 213                 kaddr = kmap_atomic(page);
 214                 offset = start & (PAGE_SIZE - 1);
 215                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 216                 kunmap_atomic(kaddr);
 217                 put_page(page);
 218         }
 219         btrfs_mark_buffer_dirty(leaf);
 220         btrfs_release_path(path);
 221
 222         /*
 223          * we're an inline extent, so nobody can
 224          * extend the file past i_size without locking
 225          * a page we already have locked.
 226          *
 227          * We must do any isize and inode updates
 228          * before we unlock the pages.  Otherwise we
 229          * could end up racing with unlink.
 230          */
 231         BTRFS_I(inode)->disk_i_size = inode->i_size;
 232         ret = btrfs_update_inode(trans, root, inode);
 233
 234         return ret;
 235 fail:
 236         return err;
 237 }
 238
 239
 240 /*
 241  * conditionally insert an inline extent into the file.  This
 242  * does the checks required to make sure the data is small enough
 243  * to fit as an inline extent.
 244  */
 245 static noinline int cow_file_range_inline(struct btrfs_root *root,
 246                                           struct inode *inode, u64 start,
 247                                           u64 end, size_t compressed_size,
 248                                           int compress_type,
 249                                           struct page **compressed_pages)
 250 {
 251         struct btrfs_trans_handle *trans;
 252         u64 isize = i_size_read(inode);
 253         u64 actual_end = min(end + 1, isize);
 254         u64 inline_len = actual_end - start;
 255         u64 aligned_end = ALIGN(end, root->sectorsize);
 256         u64 data_len = inline_len;
 257         int ret;
 258         struct btrfs_path *path;
 259         int extent_inserted = 0;
 260         u32 extent_item_size;
 261
 262         if (compressed_size)
 263                 data_len = compressed_size;
 264
 265         if (start > 0 ||
 266             actual_end > root->sectorsize ||
 267             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 268             (!compressed_size &&
 269             (actual_end & (root->sectorsize - 1)) == 0) ||
 270             end + 1 < isize ||
 271             data_len > root->fs_info->max_inline) {
 272                 return 1;
 273         }
 274
 275         path = btrfs_alloc_path();
 276         if (!path)
 277                 return -ENOMEM;
 278
 279         trans = btrfs_join_transaction(root);
 280         if (IS_ERR(trans)) {
 281                 btrfs_free_path(path);
 282                 return PTR_ERR(trans);
 283         }
 284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 285
 286         if (compressed_size && compressed_pages)
 287                 extent_item_size = btrfs_file_extent_calc_inline_size(
 288                    compressed_size);
 289         else
 290                 extent_item_size = btrfs_file_extent_calc_inline_size(
 291                     inline_len);
 292
 293         ret = __btrfs_drop_extents(trans, root, inode, path,
 294                                    start, aligned_end, NULL,
 295                                    1, 1, extent_item_size, &extent_inserted);
 296         if (ret) {
 297                 btrfs_abort_transaction(trans, root, ret);
 298                 goto out;
 299         }
 300
 301         if (isize > actual_end)
 302                 inline_len = min_t(u64, isize, actual_end);
 303         ret = insert_inline_extent(trans, path, extent_inserted,
 304                                    root, inode, start,
 305                                    inline_len, compressed_size,
 306                                    compress_type, compressed_pages);
 307         if (ret && ret != -ENOSPC) {
 308                 btrfs_abort_transaction(trans, root, ret);
 309                 goto out;
 310         } else if (ret == -ENOSPC) {
 311                 ret = 1;
 312                 goto out;
 313         }
 314
 315         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 316         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 317         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 318 out:
 319         /*
 320          * Don't forget to free the reserved space, as for inlined extent
 321          * it won't count as data extent, free them directly here.
 322          * And at reserve time, it's always aligned to page size, so
 323          * just free one page here.
 324          */
 325         btrfs_qgroup_free_data(inode, 0, PAGE_SIZE);
 326         btrfs_free_path(path);
 327         btrfs_end_transaction(trans, root);
 328         return ret;
 329 }
 330
 331 struct async_extent {
 332         u64 start;
 333         u64 ram_size;
 334         u64 compressed_size;
 335         struct page **pages;
 336         unsigned long nr_pages;
 337         int compress_type;
 338         struct list_head list;
 339 };
 340
 341 struct async_cow {
 342         struct inode *inode;
 343         struct btrfs_root *root;
 344         struct page *locked_page;
 345         u64 start;
 346         u64 end;
 347         struct list_head extents;
 348         struct btrfs_work work;
 349 };
 350
 351 static noinline int add_async_extent(struct async_cow *cow,
 352                                      u64 start, u64 ram_size,
 353                                      u64 compressed_size,
 354                                      struct page **pages,
 355                                      unsigned long nr_pages,
 356                                      int compress_type)
 357 {
 358         struct async_extent *async_extent;
 359
 360         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 361         BUG_ON(!async_extent); /* -ENOMEM */
 362         async_extent->start = start;
 363         async_extent->ram_size = ram_size;
 364         async_extent->compressed_size = compressed_size;
 365         async_extent->pages = pages;
 366         async_extent->nr_pages = nr_pages;
 367         async_extent->compress_type = compress_type;
 368         list_add_tail(&async_extent->list, &cow->extents);
 369         return 0;
 370 }
 371
 372 static inline int inode_need_compress(struct inode *inode)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375
 376         /* force compress */
 377         if (btrfs_test_opt(root, FORCE_COMPRESS))
 378                 return 1;
 379         /* bad compression ratios */
 380         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 381                 return 0;
 382         if (btrfs_test_opt(root, COMPRESS) ||
 383             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 384             BTRFS_I(inode)->force_compress)
 385                 return 1;
 386         return 0;
 387 }
 388
 389 /*
 390  * we create compressed extents in two phases.  The first
 391  * phase compresses a range of pages that have already been
 392  * locked (both pages and state bits are locked).
 393  *
 394  * This is done inside an ordered work queue, and the compression
 395  * is spread across many cpus.  The actual IO submission is step
 396  * two, and the ordered work queue takes care of making sure that
 397  * happens in the same order things were put onto the queue by
 398  * writepages and friends.
 399  *
 400  * If this code finds it can't get good compression, it puts an
 401  * entry onto the work queue to write the uncompressed bytes.  This
 402  * makes sure that both compressed inodes and uncompressed inodes
 403  * are written in the same order that the flusher thread sent them
 404  * down.
 405  */
 406 static noinline void compress_file_range(struct inode *inode,
 407                                         struct page *locked_page,
 408                                         u64 start, u64 end,
 409                                         struct async_cow *async_cow,
 410                                         int *num_added)
 411 {
 412         struct btrfs_root *root = BTRFS_I(inode)->root;
 413         u64 num_bytes;
 414         u64 blocksize = root->sectorsize;
 415         u64 actual_end;
 416         u64 isize = i_size_read(inode);
 417         int ret = 0;
 418         struct page **pages = NULL;
 419         unsigned long nr_pages;
 420         unsigned long nr_pages_ret = 0;
 421         unsigned long total_compressed = 0;
 422         unsigned long total_in = 0;
 423         unsigned long max_compressed = SZ_128K;
 424         unsigned long max_uncompressed = SZ_128K;
 425         int i;
 426         int will_compress;
 427         int compress_type = root->fs_info->compress_type;
 428         int redirty = 0;
 429
 430         /* if this is a small write inside eof, kick off a defrag */
 431         if ((end - start + 1) < SZ_16K &&
 432             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 433                 btrfs_add_inode_defrag(NULL, inode);
 434
 435         actual_end = min_t(u64, isize, end + 1);
 436 again:
 437         will_compress = 0;
 438         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 439         nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_SIZE);
 440
 441         /*
 442          * we don't want to send crud past the end of i_size through
 443          * compression, that's just a waste of CPU time.  So, if the
 444          * end of the file is before the start of our current
 445          * requested range of bytes, we bail out to the uncompressed
 446          * cleanup code that can deal with all of this.
 447          *
 448          * It isn't really the fastest way to fix things, but this is a
 449          * very uncommon corner.
 450          */
 451         if (actual_end <= start)
 452                 goto cleanup_and_bail_uncompressed;
 453
 454         total_compressed = actual_end - start;
 455
 456         /*
 457          * skip compression for a small file range(<=blocksize) that
 458          * isn't an inline extent, since it doesn't save disk space at all.
 459          */
 460         if (total_compressed <= blocksize &&
 461            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 462                 goto cleanup_and_bail_uncompressed;
 463
 464         /* we want to make sure that amount of ram required to uncompress
 465          * an extent is reasonable, so we limit the total size in ram
 466          * of a compressed extent to 128k.  This is a crucial number
 467          * because it also controls how easily we can spread reads across
 468          * cpus for decompression.
 469          *
 470          * We also want to make sure the amount of IO required to do
 471          * a random read is reasonably small, so we limit the size of
 472          * a compressed extent to 128k.
 473          */
 474         total_compressed = min(total_compressed, max_uncompressed);
 475         num_bytes = ALIGN(end - start + 1, blocksize);
 476         num_bytes = max(blocksize,  num_bytes);
 477         total_in = 0;
 478         ret = 0;
 479
 480         /*
 481          * we do compression for mount -o compress and when the
 482          * inode has not been flagged as nocompress.  This flag can
 483          * change at any time if we discover bad compression ratios.
 484          */
 485         if (inode_need_compress(inode)) {
 486                 WARN_ON(pages);
 487                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 488                 if (!pages) {
 489                         /* just bail out to the uncompressed code */
 490                         goto cont;
 491                 }
 492
 493                 if (BTRFS_I(inode)->force_compress)
 494                         compress_type = BTRFS_I(inode)->force_compress;
 495
 496                 /*
 497                  * we need to call clear_page_dirty_for_io on each
 498                  * page in the range.  Otherwise applications with the file
 499                  * mmap'd can wander in and change the page contents while
 500                  * we are compressing them.
 501                  *
 502                  * If the compression fails for any reason, we set the pages
 503                  * dirty again later on.
 504                  */
 505                 extent_range_clear_dirty_for_io(inode, start, end);
 506                 redirty = 1;
 507                 ret = btrfs_compress_pages(compress_type,
 508                                            inode->i_mapping, start,
 509                                            total_compressed, pages,
 510                                            nr_pages, &nr_pages_ret,
 511                                            &total_in,
 512                                            &total_compressed,
 513                                            max_compressed);
 514
 515                 if (!ret) {
 516                         unsigned long offset = total_compressed &
 517                                 (PAGE_SIZE - 1);
 518                         struct page *page = pages[nr_pages_ret - 1];
 519                         char *kaddr;
 520
 521                         /* zero the tail end of the last page, we might be
 522                          * sending it down to disk
 523                          */
 524                         if (offset) {
 525                                 kaddr = kmap_atomic(page);
 526                                 memset(kaddr + offset, 0,
 527                                        PAGE_SIZE - offset);
 528                                 kunmap_atomic(kaddr);
 529                         }
 530                         will_compress = 1;
 531                 }
 532         }
 533 cont:
 534         if (start == 0) {
 535                 /* lets try to make an inline extent */
 536                 if (ret || total_in < (actual_end - start)) {
 537                         /* we didn't compress the entire range, try
 538                          * to make an uncompressed inline extent.
 539                          */
 540                         ret = cow_file_range_inline(root, inode, start, end,
 541                                                     0, 0, NULL);
 542                 } else {
 543                         /* try making a compressed inline extent */
 544                         ret = cow_file_range_inline(root, inode, start, end,
 545                                                     total_compressed,
 546                                                     compress_type, pages);
 547                 }
 548                 if (ret <= 0) {
 549                         unsigned long clear_flags = EXTENT_DELALLOC |
 550                                 EXTENT_DEFRAG;
 551                         unsigned long page_error_op;
 552
 553                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 554                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 555
 556                         /*
 557                          * inline extent creation worked or returned error,
 558                          * we don't need to create any more async work items.
 559                          * Unlock and free up our temp pages.
 560                          */
 561                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 562                                                      clear_flags, PAGE_UNLOCK |
 563                                                      PAGE_CLEAR_DIRTY |
 564                                                      PAGE_SET_WRITEBACK |
 565                                                      page_error_op |
 566                                                      PAGE_END_WRITEBACK);
 567                         goto free_pages_out;
 568                 }
 569         }
 570
 571         if (will_compress) {
 572                 /*
 573                  * we aren't doing an inline extent round the compressed size
 574                  * up to a block size boundary so the allocator does sane
 575                  * things
 576                  */
 577                 total_compressed = ALIGN(total_compressed, blocksize);
 578
 579                 /*
 580                  * one last check to make sure the compression is really a
 581                  * win, compare the page count read with the blocks on disk
 582                  */
 583                 total_in = ALIGN(total_in, PAGE_SIZE);
 584                 if (total_compressed >= total_in) {
 585                         will_compress = 0;
 586                 } else {
 587                         num_bytes = total_in;
 588                 }
 589         }
 590         if (!will_compress && pages) {
 591                 /*
 592                  * the compression code ran but failed to make things smaller,
 593                  * free any pages it allocated and our page pointer array
 594                  */
 595                 for (i = 0; i < nr_pages_ret; i++) {
 596                         WARN_ON(pages[i]->mapping);
 597                         put_page(pages[i]);
 598                 }
 599                 kfree(pages);
 600                 pages = NULL;
 601                 total_compressed = 0;
 602                 nr_pages_ret = 0;
 603
 604                 /* flag the file so we don't compress in the future */
 605                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 606                     !(BTRFS_I(inode)->force_compress)) {
 607                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 608                 }
 609         }
 610         if (will_compress) {
 611                 *num_added += 1;
 612
 613                 /* the async work queues will take care of doing actual
 614                  * allocation on disk for these compressed pages,
 615                  * and will submit them to the elevator.
 616                  */
 617                 add_async_extent(async_cow, start, num_bytes,
 618                                  total_compressed, pages, nr_pages_ret,
 619                                  compress_type);
 620
 621                 if (start + num_bytes < end) {
 622                         start += num_bytes;
 623                         pages = NULL;
 624                         cond_resched();
 625                         goto again;
 626                 }
 627         } else {
 628 cleanup_and_bail_uncompressed:
 629                 /*
 630                  * No compression, but we still need to write the pages in
 631                  * the file we've been given so far.  redirty the locked
 632                  * page if it corresponds to our extent and set things up
 633                  * for the async work queue to run cow_file_range to do
 634                  * the normal delalloc dance
 635                  */
 636                 if (page_offset(locked_page) >= start &&
 637                     page_offset(locked_page) <= end) {
 638                         __set_page_dirty_nobuffers(locked_page);
 639                         /* unlocked later on in the async handlers */
 640                 }
 641                 if (redirty)
 642                         extent_range_redirty_for_io(inode, start, end);
 643                 add_async_extent(async_cow, start, end - start + 1,
 644                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 645                 *num_added += 1;
 646         }
 647
 648         return;
 649
 650 free_pages_out:
 651         for (i = 0; i < nr_pages_ret; i++) {
 652                 WARN_ON(pages[i]->mapping);
 653                 put_page(pages[i]);
 654         }
 655         kfree(pages);
 656 }
 657
 658 static void free_async_extent_pages(struct async_extent *async_extent)
 659 {
 660         int i;
 661
 662         if (!async_extent->pages)
 663                 return;
 664
 665         for (i = 0; i < async_extent->nr_pages; i++) {
 666                 WARN_ON(async_extent->pages[i]->mapping);
 667                 put_page(async_extent->pages[i]);
 668         }
 669         kfree(async_extent->pages);
 670         async_extent->nr_pages = 0;
 671         async_extent->pages = NULL;
 672 }
 673
 674 /*
 675  * phase two of compressed writeback.  This is the ordered portion
 676  * of the code, which only gets called in the order the work was
 677  * queued.  We walk all the async extents created by compress_file_range
 678  * and send them down to the disk.
 679  */
 680 static noinline void submit_compressed_extents(struct inode *inode,
 681                                               struct async_cow *async_cow)
 682 {
 683         struct async_extent *async_extent;
 684         u64 alloc_hint = 0;
 685         struct btrfs_key ins;
 686         struct extent_map *em;
 687         struct btrfs_root *root = BTRFS_I(inode)->root;
 688         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 689         struct extent_io_tree *io_tree;
 690         int ret = 0;
 691
 692 again:
 693         while (!list_empty(&async_cow->extents)) {
 694                 async_extent = list_entry(async_cow->extents.next,
 695                                           struct async_extent, list);
 696                 list_del(&async_extent->list);
 697
 698                 io_tree = &BTRFS_I(inode)->io_tree;
 699
 700 retry:
 701                 /* did the compression code fall back to uncompressed IO? */
 702                 if (!async_extent->pages) {
 703                         int page_started = 0;
 704                         unsigned long nr_written = 0;
 705
 706                         lock_extent(io_tree, async_extent->start,
 707                                          async_extent->start +
 708                                          async_extent->ram_size - 1);
 709
 710                         /* allocate blocks */
 711                         ret = cow_file_range(inode, async_cow->locked_page,
 712                                              async_extent->start,
 713                                              async_extent->start +
 714                                              async_extent->ram_size - 1,
 715                                              &page_started, &nr_written, 0);
 716
 717                         /* JDM XXX */
 718
 719                         /*
 720                          * if page_started, cow_file_range inserted an
 721                          * inline extent and took care of all the unlocking
 722                          * and IO for us.  Otherwise, we need to submit
 723                          * all those pages down to the drive.
 724                          */
 725                         if (!page_started && !ret)
 726                                 extent_write_locked_range(io_tree,
 727                                                   inode, async_extent->start,
 728                                                   async_extent->start +
 729                                                   async_extent->ram_size - 1,
 730                                                   btrfs_get_extent,
 731                                                   WB_SYNC_ALL);
 732                         else if (ret)
 733                                 unlock_page(async_cow->locked_page);
 734                         kfree(async_extent);
 735                         cond_resched();
 736                         continue;
 737                 }
 738
 739                 lock_extent(io_tree, async_extent->start,
 740                             async_extent->start + async_extent->ram_size - 1);
 741
 742                 ret = btrfs_reserve_extent(root,
 743                                            async_extent->compressed_size,
 744                                            async_extent->compressed_size,
 745                                            0, alloc_hint, &ins, 1, 1);
 746                 if (ret) {
 747                         free_async_extent_pages(async_extent);
 748
 749                         if (ret == -ENOSPC) {
 750                                 unlock_extent(io_tree, async_extent->start,
 751                                               async_extent->start +
 752                                               async_extent->ram_size - 1);
 753
 754                                 /*
 755                                  * we need to redirty the pages if we decide to
 756                                  * fallback to uncompressed IO, otherwise we
 757                                  * will not submit these pages down to lower
 758                                  * layers.
 759                                  */
 760                                 extent_range_redirty_for_io(inode,
 761                                                 async_extent->start,
 762                                                 async_extent->start +
 763                                                 async_extent->ram_size - 1);
 764
 765                                 goto retry;
 766                         }
 767                         goto out_free;
 768                 }
 769                 /*
 770                  * here we're doing allocation and writeback of the
 771                  * compressed pages
 772                  */
 773                 btrfs_drop_extent_cache(inode, async_extent->start,
 774                                         async_extent->start +
 775                                         async_extent->ram_size - 1, 0);
 776
 777                 em = alloc_extent_map();
 778                 if (!em) {
 779                         ret = -ENOMEM;
 780                         goto out_free_reserve;
 781                 }
 782                 em->start = async_extent->start;
 783                 em->len = async_extent->ram_size;
 784                 em->orig_start = em->start;
 785                 em->mod_start = em->start;
 786                 em->mod_len = em->len;
 787
 788                 em->block_start = ins.objectid;
 789                 em->block_len = ins.offset;
 790                 em->orig_block_len = ins.offset;
 791                 em->ram_bytes = async_extent->ram_size;
 792                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 793                 em->compress_type = async_extent->compress_type;
 794                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 795                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 796                 em->generation = -1;
 797
 798                 while (1) {
 799                         write_lock(&em_tree->lock);
 800                         ret = add_extent_mapping(em_tree, em, 1);
 801                         write_unlock(&em_tree->lock);
 802                         if (ret != -EEXIST) {
 803                                 free_extent_map(em);
 804                                 break;
 805                         }
 806                         btrfs_drop_extent_cache(inode, async_extent->start,
 807                                                 async_extent->start +
 808                                                 async_extent->ram_size - 1, 0);
 809                 }
 810
 811                 if (ret)
 812                         goto out_free_reserve;
 813
 814                 ret = btrfs_add_ordered_extent_compress(inode,
 815                                                 async_extent->start,
 816                                                 ins.objectid,
 817                                                 async_extent->ram_size,
 818                                                 ins.offset,
 819                                                 BTRFS_ORDERED_COMPRESSED,
 820                                                 async_extent->compress_type);
 821                 if (ret) {
 822                         btrfs_drop_extent_cache(inode, async_extent->start,
 823                                                 async_extent->start +
 824                                                 async_extent->ram_size - 1, 0);
 825                         goto out_free_reserve;
 826                 }
 827                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
 828
 829                 /*
 830                  * clear dirty, set writeback and unlock the pages.
 831                  */
 832                 extent_clear_unlock_delalloc(inode, async_extent->start,
 833                                 async_extent->start +
 834                                 async_extent->ram_size - 1,
 835                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 836                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 837                                 PAGE_SET_WRITEBACK);
 838                 ret = btrfs_submit_compressed_write(inode,
 839                                     async_extent->start,
 840                                     async_extent->ram_size,
 841                                     ins.objectid,
 842                                     ins.offset, async_extent->pages,
 843                                     async_extent->nr_pages);
 844                 if (ret) {
 845                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 846                         struct page *p = async_extent->pages[0];
 847                         const u64 start = async_extent->start;
 848                         const u64 end = start + async_extent->ram_size - 1;
 849
 850                         p->mapping = inode->i_mapping;
 851                         tree->ops->writepage_end_io_hook(p, start, end,
 852                                                          NULL, 0);
 853                         p->mapping = NULL;
 854                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 855                                                      PAGE_END_WRITEBACK |
 856                                                      PAGE_SET_ERROR);
 857                         free_async_extent_pages(async_extent);
 858                 }
 859                 alloc_hint = ins.objectid + ins.offset;
 860                 kfree(async_extent);
 861                 cond_resched();
 862         }
 863         return;
 864 out_free_reserve:
 865         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
 866         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 867 out_free:
 868         extent_clear_unlock_delalloc(inode, async_extent->start,
 869                                      async_extent->start +
 870                                      async_extent->ram_size - 1,
 871                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 872                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 873                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 874                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 875                                      PAGE_SET_ERROR);
 876         free_async_extent_pages(async_extent);
 877         kfree(async_extent);
 878         goto again;
 879 }
 880
 881 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 882                                       u64 num_bytes)
 883 {
 884         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 885         struct extent_map *em;
 886         u64 alloc_hint = 0;
 887
 888         read_lock(&em_tree->lock);
 889         em = search_extent_mapping(em_tree, start, num_bytes);
 890         if (em) {
 891                 /*
 892                  * if block start isn't an actual block number then find the
 893                  * first block in this inode and use that as a hint.  If that
 894                  * block is also bogus then just don't worry about it.
 895                  */
 896                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 897                         free_extent_map(em);
 898                         em = search_extent_mapping(em_tree, 0, 0);
 899                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 900                                 alloc_hint = em->block_start;
 901                         if (em)
 902                                 free_extent_map(em);
 903                 } else {
 904                         alloc_hint = em->block_start;
 905                         free_extent_map(em);
 906                 }
 907         }
 908         read_unlock(&em_tree->lock);
 909
 910         return alloc_hint;
 911 }
 912
 913 /*
 914  * when extent_io.c finds a delayed allocation range in the file,
 915  * the call backs end up in this code.  The basic idea is to
 916  * allocate extents on disk for the range, and create ordered data structs
 917  * in ram to track those extents.
 918  *
 919  * locked_page is the page that writepage had locked already.  We use
 920  * it to make sure we don't do extra locks or unlocks.
 921  *
 922  * *page_started is set to one if we unlock locked_page and do everything
 923  * required to start IO on it.  It may be clean and already done with
 924  * IO when we return.
 925  */
 926 static noinline int cow_file_range(struct inode *inode,
 927                                    struct page *locked_page,
 928                                    u64 start, u64 end, int *page_started,
 929                                    unsigned long *nr_written,
 930                                    int unlock)
 931 {
 932         struct btrfs_root *root = BTRFS_I(inode)->root;
 933         u64 alloc_hint = 0;
 934         u64 num_bytes;
 935         unsigned long ram_size;
 936         u64 disk_num_bytes;
 937         u64 cur_alloc_size;
 938         u64 blocksize = root->sectorsize;
 939         struct btrfs_key ins;
 940         struct extent_map *em;
 941         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 942         int ret = 0;
 943
 944         if (btrfs_is_free_space_inode(inode)) {
 945                 WARN_ON_ONCE(1);
 946                 ret = -EINVAL;
 947                 goto out_unlock;
 948         }
 949
 950         num_bytes = ALIGN(end - start + 1, blocksize);
 951         num_bytes = max(blocksize,  num_bytes);
 952         disk_num_bytes = num_bytes;
 953
 954         /* if this is a small write inside eof, kick off defrag */
 955         if (num_bytes < SZ_64K &&
 956             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 957                 btrfs_add_inode_defrag(NULL, inode);
 958
 959         if (start == 0) {
 960                 /* lets try to make an inline extent */
 961                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 962                                             NULL);
 963                 if (ret == 0) {
 964                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 965                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 966                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 967                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 968                                      PAGE_END_WRITEBACK);
 969
 970                         *nr_written = *nr_written +
 971                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 972                         *page_started = 1;
 973                         goto out;
 974                 } else if (ret < 0) {
 975                         goto out_unlock;
 976                 }
 977         }
 978
 979         BUG_ON(disk_num_bytes >
 980                btrfs_super_total_bytes(root->fs_info->super_copy));
 981
 982         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 983         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 984
 985         while (disk_num_bytes > 0) {
 986                 unsigned long op;
 987
 988                 cur_alloc_size = disk_num_bytes;
 989                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 990                                            root->sectorsize, 0, alloc_hint,
 991                                            &ins, 1, 1);
 992                 if (ret < 0)
 993                         goto out_unlock;
 994
 995                 em = alloc_extent_map();
 996                 if (!em) {
 997                         ret = -ENOMEM;
 998                         goto out_reserve;
 999                 }
1000                 em->start = start;
1001                 em->orig_start = em->start;
1002                 ram_size = ins.offset;
1003                 em->len = ins.offset;
1004                 em->mod_start = em->start;
1005                 em->mod_len = em->len;
1006
1007                 em->block_start = ins.objectid;
1008                 em->block_len = ins.offset;
1009                 em->orig_block_len = ins.offset;
1010                 em->ram_bytes = ram_size;
1011                 em->bdev = root->fs_info->fs_devices->latest_bdev;
1012                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
1013                 em->generation = -1;
1014
1015                 while (1) {
1016                         write_lock(&em_tree->lock);
1017                         ret = add_extent_mapping(em_tree, em, 1);
1018                         write_unlock(&em_tree->lock);
1019                         if (ret != -EEXIST) {
1020                                 free_extent_map(em);
1021                                 break;
1022                         }
1023                         btrfs_drop_extent_cache(inode, start,
1024                                                 start + ram_size - 1, 0);
1025                 }
1026                 if (ret)
1027                         goto out_reserve;
1028
1029                 cur_alloc_size = ins.offset;
1030                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1031                                                ram_size, cur_alloc_size, 0);
1032                 if (ret)
1033                         goto out_drop_extent_cache;
1034
1035                 if (root->root_key.objectid ==
1036                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1037                         ret = btrfs_reloc_clone_csums(inode, start,
1038                                                       cur_alloc_size);
1039                         if (ret)
1040                                 goto out_drop_extent_cache;
1041                 }
1042
1043                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
1044
1045                 if (disk_num_bytes < cur_alloc_size)
1046                         break;
1047
1048                 /* we're not doing compressed IO, don't unlock the first
1049                  * page (which the caller expects to stay locked), don't
1050                  * clear any dirty bits and don't set any writeback bits
1051                  *
1052                  * Do set the Private2 bit so we know this page was properly
1053                  * setup for writepage
1054                  */
1055                 op = unlock ? PAGE_UNLOCK : 0;
1056                 op |= PAGE_SET_PRIVATE2;
1057
1058                 extent_clear_unlock_delalloc(inode, start,
1059                                              start + ram_size - 1, locked_page,
1060                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1061                                              op);
1062                 disk_num_bytes -= cur_alloc_size;
1063                 num_bytes -= cur_alloc_size;
1064                 alloc_hint = ins.objectid + ins.offset;
1065                 start += cur_alloc_size;
1066         }
1067 out:
1068         return ret;
1069
1070 out_drop_extent_cache:
1071         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1072 out_reserve:
1073         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
1074         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1075 out_unlock:
1076         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1077                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1078                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1079                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1080                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1081         goto out;
1082 }
1083
1084 /*
1085  * work queue call back to started compression on a file and pages
1086  */
1087 static noinline void async_cow_start(struct btrfs_work *work)
1088 {
1089         struct async_cow *async_cow;
1090         int num_added = 0;
1091         async_cow = container_of(work, struct async_cow, work);
1092
1093         compress_file_range(async_cow->inode, async_cow->locked_page,
1094                             async_cow->start, async_cow->end, async_cow,
1095                             &num_added);
1096         if (num_added == 0) {
1097                 btrfs_add_delayed_iput(async_cow->inode);
1098                 async_cow->inode = NULL;
1099         }
1100 }
1101
1102 /*
1103  * work queue call back to submit previously compressed pages
1104  */
1105 static noinline void async_cow_submit(struct btrfs_work *work)
1106 {
1107         struct async_cow *async_cow;
1108         struct btrfs_root *root;
1109         unsigned long nr_pages;
1110
1111         async_cow = container_of(work, struct async_cow, work);
1112
1113         root = async_cow->root;
1114         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1115                 PAGE_SHIFT;
1116
1117         /*
1118          * atomic_sub_return implies a barrier for waitqueue_active
1119          */
1120         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1121             5 * SZ_1M &&
1122             waitqueue_active(&root->fs_info->async_submit_wait))
1123                 wake_up(&root->fs_info->async_submit_wait);
1124
1125         if (async_cow->inode)
1126                 submit_compressed_extents(async_cow->inode, async_cow);
1127 }
1128
1129 static noinline void async_cow_free(struct btrfs_work *work)
1130 {
1131         struct async_cow *async_cow;
1132         async_cow = container_of(work, struct async_cow, work);
1133         if (async_cow->inode)
1134                 btrfs_add_delayed_iput(async_cow->inode);
1135         kfree(async_cow);
1136 }
1137
1138 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1139                                 u64 start, u64 end, int *page_started,
1140                                 unsigned long *nr_written)
1141 {
1142         struct async_cow *async_cow;
1143         struct btrfs_root *root = BTRFS_I(inode)->root;
1144         unsigned long nr_pages;
1145         u64 cur_end;
1146         int limit = 10 * SZ_1M;
1147
1148         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1149                          1, 0, NULL, GFP_NOFS);
1150         while (start < end) {
1151                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1152                 BUG_ON(!async_cow); /* -ENOMEM */
1153                 async_cow->inode = igrab(inode);
1154                 async_cow->root = root;
1155                 async_cow->locked_page = locked_page;
1156                 async_cow->start = start;
1157
1158                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1159                     !btrfs_test_opt(root, FORCE_COMPRESS))
1160                         cur_end = end;
1161                 else
1162                         cur_end = min(end, start + SZ_512K - 1);
1163
1164                 async_cow->end = cur_end;
1165                 INIT_LIST_HEAD(&async_cow->extents);
1166
1167                 btrfs_init_work(&async_cow->work,
1168                                 btrfs_delalloc_helper,
1169                                 async_cow_start, async_cow_submit,
1170                                 async_cow_free);
1171
1172                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1173                         PAGE_SHIFT;
1174                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1175
1176                 btrfs_queue_work(root->fs_info->delalloc_workers,
1177                                  &async_cow->work);
1178
1179                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1180                         wait_event(root->fs_info->async_submit_wait,
1181                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1182                             limit));
1183                 }
1184
1185                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1186                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1187                         wait_event(root->fs_info->async_submit_wait,
1188                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1189                            0));
1190                 }
1191
1192                 *nr_written += nr_pages;
1193                 start = cur_end + 1;
1194         }
1195         *page_started = 1;
1196         return 0;
1197 }
1198
1199 static noinline int csum_exist_in_range(struct btrfs_root *root,
1200                                         u64 bytenr, u64 num_bytes)
1201 {
1202         int ret;
1203         struct btrfs_ordered_sum *sums;
1204         LIST_HEAD(list);
1205
1206         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1207                                        bytenr + num_bytes - 1, &list, 0);
1208         if (ret == 0 && list_empty(&list))
1209                 return 0;
1210
1211         while (!list_empty(&list)) {
1212                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1213                 list_del(&sums->list);
1214                 kfree(sums);
1215         }
1216         return 1;
1217 }
1218
1219 /*
1220  * when nowcow writeback call back.  This checks for snapshots or COW copies
1221  * of the extents that exist in the file, and COWs the file as required.
1222  *
1223  * If no cow copies or snapshots exist, we write directly to the existing
1224  * blocks on disk
1225  */
1226 static noinline int run_delalloc_nocow(struct inode *inode,
1227                                        struct page *locked_page,
1228                               u64 start, u64 end, int *page_started, int force,
1229                               unsigned long *nr_written)
1230 {
1231         struct btrfs_root *root = BTRFS_I(inode)->root;
1232         struct btrfs_trans_handle *trans;
1233         struct extent_buffer *leaf;
1234         struct btrfs_path *path;
1235         struct btrfs_file_extent_item *fi;
1236         struct btrfs_key found_key;
1237         u64 cow_start;
1238         u64 cur_offset;
1239         u64 extent_end;
1240         u64 extent_offset;
1241         u64 disk_bytenr;
1242         u64 num_bytes;
1243         u64 disk_num_bytes;
1244         u64 ram_bytes;
1245         int extent_type;
1246         int ret, err;
1247         int type;
1248         int nocow;
1249         int check_prev = 1;
1250         bool nolock;
1251         u64 ino = btrfs_ino(inode);
1252
1253         path = btrfs_alloc_path();
1254         if (!path) {
1255                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1256                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1257                                              EXTENT_DO_ACCOUNTING |
1258                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1259                                              PAGE_CLEAR_DIRTY |
1260                                              PAGE_SET_WRITEBACK |
1261                                              PAGE_END_WRITEBACK);
1262                 return -ENOMEM;
1263         }
1264
1265         nolock = btrfs_is_free_space_inode(inode);
1266
1267         if (nolock)
1268                 trans = btrfs_join_transaction_nolock(root);
1269         else
1270                 trans = btrfs_join_transaction(root);
1271
1272         if (IS_ERR(trans)) {
1273                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1274                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1275                                              EXTENT_DO_ACCOUNTING |
1276                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1277                                              PAGE_CLEAR_DIRTY |
1278                                              PAGE_SET_WRITEBACK |
1279                                              PAGE_END_WRITEBACK);
1280                 btrfs_free_path(path);
1281                 return PTR_ERR(trans);
1282         }
1283
1284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1285
1286         cow_start = (u64)-1;
1287         cur_offset = start;
1288         while (1) {
1289                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1290                                                cur_offset, 0);
1291                 if (ret < 0)
1292                         goto error;
1293                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1294                         leaf = path->nodes[0];
1295                         btrfs_item_key_to_cpu(leaf, &found_key,
1296                                               path->slots[0] - 1);
1297                         if (found_key.objectid == ino &&
1298                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1299                                 path->slots[0]--;
1300                 }
1301                 check_prev = 0;
1302 next_slot:
1303                 leaf = path->nodes[0];
1304                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1305                         ret = btrfs_next_leaf(root, path);
1306                         if (ret < 0)
1307                                 goto error;
1308                         if (ret > 0)
1309                                 break;
1310                         leaf = path->nodes[0];
1311                 }
1312
1313                 nocow = 0;
1314                 disk_bytenr = 0;
1315                 num_bytes = 0;
1316                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1317
1318                 if (found_key.objectid > ino)
1319                         break;
1320                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1321                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1322                         path->slots[0]++;
1323                         goto next_slot;
1324                 }
1325                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1326                     found_key.offset > end)
1327                         break;
1328
1329                 if (found_key.offset > cur_offset) {
1330                         extent_end = found_key.offset;
1331                         extent_type = 0;
1332                         goto out_check;
1333                 }
1334
1335                 fi = btrfs_item_ptr(leaf, path->slots[0],
1336                                     struct btrfs_file_extent_item);
1337                 extent_type = btrfs_file_extent_type(leaf, fi);
1338
1339                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1340                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1341                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1342                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1343                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1344                         extent_end = found_key.offset +
1345                                 btrfs_file_extent_num_bytes(leaf, fi);
1346                         disk_num_bytes =
1347                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1348                         if (extent_end <= start) {
1349                                 path->slots[0]++;
1350                                 goto next_slot;
1351                         }
1352                         if (disk_bytenr == 0)
1353                                 goto out_check;
1354                         if (btrfs_file_extent_compression(leaf, fi) ||
1355                             btrfs_file_extent_encryption(leaf, fi) ||
1356                             btrfs_file_extent_other_encoding(leaf, fi))
1357                                 goto out_check;
1358                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1359                                 goto out_check;
1360                         if (btrfs_extent_readonly(root, disk_bytenr))
1361                                 goto out_check;
1362                         if (btrfs_cross_ref_exist(trans, root, ino,
1363                                                   found_key.offset -
1364                                                   extent_offset, disk_bytenr))
1365                                 goto out_check;
1366                         disk_bytenr += extent_offset;
1367                         disk_bytenr += cur_offset - found_key.offset;
1368                         num_bytes = min(end + 1, extent_end) - cur_offset;
1369                         /*
1370                          * if there are pending snapshots for this root,
1371                          * we fall into common COW way.
1372                          */
1373                         if (!nolock) {
1374                                 err = btrfs_start_write_no_snapshoting(root);
1375                                 if (!err)
1376                                         goto out_check;
1377                         }
1378                         /*
1379                          * force cow if csum exists in the range.
1380                          * this ensure that csum for a given extent are
1381                          * either valid or do not exist.
1382                          */
1383                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1384                                 goto out_check;
1385                         if (!btrfs_inc_nocow_writers(root->fs_info,
1386                                                      disk_bytenr))
1387                                 goto out_check;
1388                         nocow = 1;
1389                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1390                         extent_end = found_key.offset +
1391                                 btrfs_file_extent_inline_len(leaf,
1392                                                      path->slots[0], fi);
1393                         extent_end = ALIGN(extent_end, root->sectorsize);
1394                 } else {
1395                         BUG_ON(1);
1396                 }
1397 out_check:
1398                 if (extent_end <= start) {
1399                         path->slots[0]++;
1400                         if (!nolock && nocow)
1401                                 btrfs_end_write_no_snapshoting(root);
1402                         if (nocow)
1403                                 btrfs_dec_nocow_writers(root->fs_info,
1404                                                         disk_bytenr);
1405                         goto next_slot;
1406                 }
1407                 if (!nocow) {
1408                         if (cow_start == (u64)-1)
1409                                 cow_start = cur_offset;
1410                         cur_offset = extent_end;
1411                         if (cur_offset > end)
1412                                 break;
1413                         path->slots[0]++;
1414                         goto next_slot;
1415                 }
1416
1417                 btrfs_release_path(path);
1418                 if (cow_start != (u64)-1) {
1419                         ret = cow_file_range(inode, locked_page,
1420                                              cow_start, found_key.offset - 1,
1421                                              page_started, nr_written, 1);
1422                         if (ret) {
1423                                 if (!nolock && nocow)
1424                                         btrfs_end_write_no_snapshoting(root);
1425                                 if (nocow)
1426                                         btrfs_dec_nocow_writers(root->fs_info,
1427                                                                 disk_bytenr);
1428                                 goto error;
1429                         }
1430                         cow_start = (u64)-1;
1431                 }
1432
1433                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1434                         struct extent_map *em;
1435                         struct extent_map_tree *em_tree;
1436                         em_tree = &BTRFS_I(inode)->extent_tree;
1437                         em = alloc_extent_map();
1438                         BUG_ON(!em); /* -ENOMEM */
1439                         em->start = cur_offset;
1440                         em->orig_start = found_key.offset - extent_offset;
1441                         em->len = num_bytes;
1442                         em->block_len = num_bytes;
1443                         em->block_start = disk_bytenr;
1444                         em->orig_block_len = disk_num_bytes;
1445                         em->ram_bytes = ram_bytes;
1446                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1447                         em->mod_start = em->start;
1448                         em->mod_len = em->len;
1449                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1450                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1451                         em->generation = -1;
1452                         while (1) {
1453                                 write_lock(&em_tree->lock);
1454                                 ret = add_extent_mapping(em_tree, em, 1);
1455                                 write_unlock(&em_tree->lock);
1456                                 if (ret != -EEXIST) {
1457                                         free_extent_map(em);
1458                                         break;
1459                                 }
1460                                 btrfs_drop_extent_cache(inode, em->start,
1461                                                 em->start + em->len - 1, 0);
1462                         }
1463                         type = BTRFS_ORDERED_PREALLOC;
1464                 } else {
1465                         type = BTRFS_ORDERED_NOCOW;
1466                 }
1467
1468                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1469                                                num_bytes, num_bytes, type);
1470                 if (nocow)
1471                         btrfs_dec_nocow_writers(root->fs_info, disk_bytenr);
1472                 BUG_ON(ret); /* -ENOMEM */
1473
1474                 if (root->root_key.objectid ==
1475                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1476                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1477                                                       num_bytes);
1478                         if (ret) {
1479                                 if (!nolock && nocow)
1480                                         btrfs_end_write_no_snapshoting(root);
1481                                 goto error;
1482                         }
1483                 }
1484
1485                 extent_clear_unlock_delalloc(inode, cur_offset,
1486                                              cur_offset + num_bytes - 1,
1487                                              locked_page, EXTENT_LOCKED |
1488                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1489                                              PAGE_SET_PRIVATE2);
1490                 if (!nolock && nocow)
1491                         btrfs_end_write_no_snapshoting(root);
1492                 cur_offset = extent_end;
1493                 if (cur_offset > end)
1494                         break;
1495         }
1496         btrfs_release_path(path);
1497
1498         if (cur_offset <= end && cow_start == (u64)-1) {
1499                 cow_start = cur_offset;
1500                 cur_offset = end;
1501         }
1502
1503         if (cow_start != (u64)-1) {
1504                 ret = cow_file_range(inode, locked_page, cow_start, end,
1505                                      page_started, nr_written, 1);
1506                 if (ret)
1507                         goto error;
1508         }
1509
1510 error:
1511         err = btrfs_end_transaction(trans, root);
1512         if (!ret)
1513                 ret = err;
1514
1515         if (ret && cur_offset < end)
1516                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1517                                              locked_page, EXTENT_LOCKED |
1518                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1519                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1520                                              PAGE_CLEAR_DIRTY |
1521                                              PAGE_SET_WRITEBACK |
1522                                              PAGE_END_WRITEBACK);
1523         btrfs_free_path(path);
1524         return ret;
1525 }
1526
1527 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1528 {
1529
1530         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1531             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1532                 return 0;
1533
1534         /*
1535          * @defrag_bytes is a hint value, no spinlock held here,
1536          * if is not zero, it means the file is defragging.
1537          * Force cow if given extent needs to be defragged.
1538          */
1539         if (BTRFS_I(inode)->defrag_bytes &&
1540             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1541                            EXTENT_DEFRAG, 0, NULL))
1542                 return 1;
1543
1544         return 0;
1545 }
1546
1547 /*
1548  * extent_io.c call back to do delayed allocation processing
1549  */
1550 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1551                               u64 start, u64 end, int *page_started,
1552                               unsigned long *nr_written)
1553 {
1554         int ret;
1555         int force_cow = need_force_cow(inode, start, end);
1556
1557         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1558                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1559                                          page_started, 1, nr_written);
1560         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1561                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1562                                          page_started, 0, nr_written);
1563         } else if (!inode_need_compress(inode)) {
1564                 ret = cow_file_range(inode, locked_page, start, end,
1565                                       page_started, nr_written, 1);
1566         } else {
1567                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1568                         &BTRFS_I(inode)->runtime_flags);
1569                 ret = cow_file_range_async(inode, locked_page, start, end,
1570                                            page_started, nr_written);
1571         }
1572         return ret;
1573 }
1574
1575 static void btrfs_split_extent_hook(struct inode *inode,
1576                                     struct extent_state *orig, u64 split)
1577 {
1578         u64 size;
1579
1580         /* not delalloc, ignore it */
1581         if (!(orig->state & EXTENT_DELALLOC))
1582                 return;
1583
1584         size = orig->end - orig->start + 1;
1585         if (size > BTRFS_MAX_EXTENT_SIZE) {
1586                 u64 num_extents;
1587                 u64 new_size;
1588
1589                 /*
1590                  * See the explanation in btrfs_merge_extent_hook, the same
1591                  * applies here, just in reverse.
1592                  */
1593                 new_size = orig->end - split + 1;
1594                 num_extents = div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1595                                         BTRFS_MAX_EXTENT_SIZE);
1596                 new_size = split - orig->start;
1597                 num_extents += div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1598                                         BTRFS_MAX_EXTENT_SIZE);
1599                 if (div64_u64(size + BTRFS_MAX_EXTENT_SIZE - 1,
1600                               BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1601                         return;
1602         }
1603
1604         spin_lock(&BTRFS_I(inode)->lock);
1605         BTRFS_I(inode)->outstanding_extents++;
1606         spin_unlock(&BTRFS_I(inode)->lock);
1607 }
1608
1609 /*
1610  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1611  * extents so we can keep track of new extents that are just merged onto old
1612  * extents, such as when we are doing sequential writes, so we can properly
1613  * account for the metadata space we'll need.
1614  */
1615 static void btrfs_merge_extent_hook(struct inode *inode,
1616                                     struct extent_state *new,
1617                                     struct extent_state *other)
1618 {
1619         u64 new_size, old_size;
1620         u64 num_extents;
1621
1622         /* not delalloc, ignore it */
1623         if (!(other->state & EXTENT_DELALLOC))
1624                 return;
1625
1626         if (new->start > other->start)
1627                 new_size = new->end - other->start + 1;
1628         else
1629                 new_size = other->end - new->start + 1;
1630
1631         /* we're not bigger than the max, unreserve the space and go */
1632         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1633                 spin_lock(&BTRFS_I(inode)->lock);
1634                 BTRFS_I(inode)->outstanding_extents--;
1635                 spin_unlock(&BTRFS_I(inode)->lock);
1636                 return;
1637         }
1638
1639         /*
1640          * We have to add up either side to figure out how many extents were
1641          * accounted for before we merged into one big extent.  If the number of
1642          * extents we accounted for is <= the amount we need for the new range
1643          * then we can return, otherwise drop.  Think of it like this
1644          *
1645          * [ 4k][MAX_SIZE]
1646          *
1647          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1648          * need 2 outstanding extents, on one side we have 1 and the other side
1649          * we have 1 so they are == and we can return.  But in this case
1650          *
1651          * [MAX_SIZE+4k][MAX_SIZE+4k]
1652          *
1653          * Each range on their own accounts for 2 extents, but merged together
1654          * they are only 3 extents worth of accounting, so we need to drop in
1655          * this case.
1656          */
1657         old_size = other->end - other->start + 1;
1658         num_extents = div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1659                                 BTRFS_MAX_EXTENT_SIZE);
1660         old_size = new->end - new->start + 1;
1661         num_extents += div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1662                                  BTRFS_MAX_EXTENT_SIZE);
1663
1664         if (div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1665                       BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1666                 return;
1667
1668         spin_lock(&BTRFS_I(inode)->lock);
1669         BTRFS_I(inode)->outstanding_extents--;
1670         spin_unlock(&BTRFS_I(inode)->lock);
1671 }
1672
1673 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1674                                       struct inode *inode)
1675 {
1676         spin_lock(&root->delalloc_lock);
1677         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1678                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1679                               &root->delalloc_inodes);
1680                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1681                         &BTRFS_I(inode)->runtime_flags);
1682                 root->nr_delalloc_inodes++;
1683                 if (root->nr_delalloc_inodes == 1) {
1684                         spin_lock(&root->fs_info->delalloc_root_lock);
1685                         BUG_ON(!list_empty(&root->delalloc_root));
1686                         list_add_tail(&root->delalloc_root,
1687                                       &root->fs_info->delalloc_roots);
1688                         spin_unlock(&root->fs_info->delalloc_root_lock);
1689                 }
1690         }
1691         spin_unlock(&root->delalloc_lock);
1692 }
1693
1694 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1695                                      struct inode *inode)
1696 {
1697         spin_lock(&root->delalloc_lock);
1698         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1699                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1700                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1701                           &BTRFS_I(inode)->runtime_flags);
1702                 root->nr_delalloc_inodes--;
1703                 if (!root->nr_delalloc_inodes) {
1704                         spin_lock(&root->fs_info->delalloc_root_lock);
1705                         BUG_ON(list_empty(&root->delalloc_root));
1706                         list_del_init(&root->delalloc_root);
1707                         spin_unlock(&root->fs_info->delalloc_root_lock);
1708                 }
1709         }
1710         spin_unlock(&root->delalloc_lock);
1711 }
1712
1713 /*
1714  * extent_io.c set_bit_hook, used to track delayed allocation
1715  * bytes in this file, and to maintain the list of inodes that
1716  * have pending delalloc work to be done.
1717  */
1718 static void btrfs_set_bit_hook(struct inode *inode,
1719                                struct extent_state *state, unsigned *bits)
1720 {
1721
1722         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1723                 WARN_ON(1);
1724         /*
1725          * set_bit and clear bit hooks normally require _irqsave/restore
1726          * but in this case, we are only testing for the DELALLOC
1727          * bit, which is only set or cleared with irqs on
1728          */
1729         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1730                 struct btrfs_root *root = BTRFS_I(inode)->root;
1731                 u64 len = state->end + 1 - state->start;
1732                 bool do_list = !btrfs_is_free_space_inode(inode);
1733
1734                 if (*bits & EXTENT_FIRST_DELALLOC) {
1735                         *bits &= ~EXTENT_FIRST_DELALLOC;
1736                 } else {
1737                         spin_lock(&BTRFS_I(inode)->lock);
1738                         BTRFS_I(inode)->outstanding_extents++;
1739                         spin_unlock(&BTRFS_I(inode)->lock);
1740                 }
1741
1742                 /* For sanity tests */
1743                 if (btrfs_test_is_dummy_root(root))
1744                         return;
1745
1746                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1747                                      root->fs_info->delalloc_batch);
1748                 spin_lock(&BTRFS_I(inode)->lock);
1749                 BTRFS_I(inode)->delalloc_bytes += len;
1750                 if (*bits & EXTENT_DEFRAG)
1751                         BTRFS_I(inode)->defrag_bytes += len;
1752                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1753                                          &BTRFS_I(inode)->runtime_flags))
1754                         btrfs_add_delalloc_inodes(root, inode);
1755                 spin_unlock(&BTRFS_I(inode)->lock);
1756         }
1757 }
1758
1759 /*
1760  * extent_io.c clear_bit_hook, see set_bit_hook for why
1761  */
1762 static void btrfs_clear_bit_hook(struct inode *inode,
1763                                  struct extent_state *state,
1764                                  unsigned *bits)
1765 {
1766         u64 len = state->end + 1 - state->start;
1767         u64 num_extents = div64_u64(len + BTRFS_MAX_EXTENT_SIZE -1,
1768                                     BTRFS_MAX_EXTENT_SIZE);
1769
1770         spin_lock(&BTRFS_I(inode)->lock);
1771         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1772                 BTRFS_I(inode)->defrag_bytes -= len;
1773         spin_unlock(&BTRFS_I(inode)->lock);
1774
1775         /*
1776          * set_bit and clear bit hooks normally require _irqsave/restore
1777          * but in this case, we are only testing for the DELALLOC
1778          * bit, which is only set or cleared with irqs on
1779          */
1780         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1781                 struct btrfs_root *root = BTRFS_I(inode)->root;
1782                 bool do_list = !btrfs_is_free_space_inode(inode);
1783
1784                 if (*bits & EXTENT_FIRST_DELALLOC) {
1785                         *bits &= ~EXTENT_FIRST_DELALLOC;
1786                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1787                         spin_lock(&BTRFS_I(inode)->lock);
1788                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1789                         spin_unlock(&BTRFS_I(inode)->lock);
1790                 }
1791
1792                 /*
1793                  * We don't reserve metadata space for space cache inodes so we
1794                  * don't need to call dellalloc_release_metadata if there is an
1795                  * error.
1796                  */
1797                 if (*bits & EXTENT_DO_ACCOUNTING &&
1798                     root != root->fs_info->tree_root)
1799                         btrfs_delalloc_release_metadata(inode, len);
1800
1801                 /* For sanity tests. */
1802                 if (btrfs_test_is_dummy_root(root))
1803                         return;
1804
1805                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1806                     && do_list && !(state->state & EXTENT_NORESERVE))
1807                         btrfs_free_reserved_data_space_noquota(inode,
1808                                         state->start, len);
1809
1810                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1811                                      root->fs_info->delalloc_batch);
1812                 spin_lock(&BTRFS_I(inode)->lock);
1813                 BTRFS_I(inode)->delalloc_bytes -= len;
1814                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1815                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1816                              &BTRFS_I(inode)->runtime_flags))
1817                         btrfs_del_delalloc_inode(root, inode);
1818                 spin_unlock(&BTRFS_I(inode)->lock);
1819         }
1820 }
1821
1822 /*
1823  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1824  * we don't create bios that span stripes or chunks
1825  */
1826 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1827                          size_t size, struct bio *bio,
1828                          unsigned long bio_flags)
1829 {
1830         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1831         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1832         u64 length = 0;
1833         u64 map_length;
1834         int ret;
1835
1836         if (bio_flags & EXTENT_BIO_COMPRESSED)
1837                 return 0;
1838
1839         length = bio->bi_iter.bi_size;
1840         map_length = length;
1841         ret = btrfs_map_block(root->fs_info, bio_op(bio), logical,
1842                               &map_length, NULL, 0);
1843         /* Will always return 0 with map_multi == NULL */
1844         BUG_ON(ret < 0);
1845         if (map_length < length + size)
1846                 return 1;
1847         return 0;
1848 }
1849
1850 /*
1851  * in order to insert checksums into the metadata in large chunks,
1852  * we wait until bio submission time.   All the pages in the bio are
1853  * checksummed and sums are attached onto the ordered extent record.
1854  *
1855  * At IO completion time the cums attached on the ordered extent record
1856  * are inserted into the btree
1857  */
1858 static int __btrfs_submit_bio_start(struct inode *inode, struct bio *bio,
1859                                     int mirror_num, unsigned long bio_flags,
1860                                     u64 bio_offset)
1861 {
1862         struct btrfs_root *root = BTRFS_I(inode)->root;
1863         int ret = 0;
1864
1865         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1866         BUG_ON(ret); /* -ENOMEM */
1867         return 0;
1868 }
1869
1870 /*
1871  * in order to insert checksums into the metadata in large chunks,
1872  * we wait until bio submission time.   All the pages in the bio are
1873  * checksummed and sums are attached onto the ordered extent record.
1874  *
1875  * At IO completion time the cums attached on the ordered extent record
1876  * are inserted into the btree
1877  */
1878 static int __btrfs_submit_bio_done(struct inode *inode, struct bio *bio,
1879                           int mirror_num, unsigned long bio_flags,
1880                           u64 bio_offset)
1881 {
1882         struct btrfs_root *root = BTRFS_I(inode)->root;
1883         int ret;
1884
1885         ret = btrfs_map_bio(root, bio, mirror_num, 1);
1886         if (ret) {
1887                 bio->bi_error = ret;
1888                 bio_endio(bio);
1889         }
1890         return ret;
1891 }
1892
1893 /*
1894  * extent_io.c submission hook. This does the right thing for csum calculation
1895  * on write, or reading the csums from the tree before a read
1896  */
1897 static int btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
1898                           int mirror_num, unsigned long bio_flags,
1899                           u64 bio_offset)
1900 {
1901         struct btrfs_root *root = BTRFS_I(inode)->root;
1902         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1903         int ret = 0;
1904         int skip_sum;
1905         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1906
1907         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1908
1909         if (btrfs_is_free_space_inode(inode))
1910                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1911
1912         if (bio_op(bio) != REQ_OP_WRITE) {
1913                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1914                 if (ret)
1915                         goto out;
1916
1917                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1918                         ret = btrfs_submit_compressed_read(inode, bio,
1919                                                            mirror_num,
1920                                                            bio_flags);
1921                         goto out;
1922                 } else if (!skip_sum) {
1923                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1924                         if (ret)
1925                                 goto out;
1926                 }
1927                 goto mapit;
1928         } else if (async && !skip_sum) {
1929                 /* csum items have already been cloned */
1930                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1931                         goto mapit;
1932                 /* we're doing a write, do the async checksumming */
1933                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1934                                    inode, bio, mirror_num,
1935                                    bio_flags, bio_offset,
1936                                    __btrfs_submit_bio_start,
1937                                    __btrfs_submit_bio_done);
1938                 goto out;
1939         } else if (!skip_sum) {
1940                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1941                 if (ret)
1942                         goto out;
1943         }
1944
1945 mapit:
1946         ret = btrfs_map_bio(root, bio, mirror_num, 0);
1947
1948 out:
1949         if (ret < 0) {
1950                 bio->bi_error = ret;
1951                 bio_endio(bio);
1952         }
1953         return ret;
1954 }
1955
1956 /*
1957  * given a list of ordered sums record them in the inode.  This happens
1958  * at IO completion time based on sums calculated at bio submission time.
1959  */
1960 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1961                              struct inode *inode, u64 file_offset,
1962                              struct list_head *list)
1963 {
1964         struct btrfs_ordered_sum *sum;
1965
1966         list_for_each_entry(sum, list, list) {
1967                 trans->adding_csums = 1;
1968                 btrfs_csum_file_blocks(trans,
1969                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1970                 trans->adding_csums = 0;
1971         }
1972         return 0;
1973 }
1974
1975 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1976                               struct extent_state **cached_state)
1977 {
1978         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
1979         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1980                                    cached_state);
1981 }
1982
1983 /* see btrfs_writepage_start_hook for details on why this is required */
1984 struct btrfs_writepage_fixup {
1985         struct page *page;
1986         struct btrfs_work work;
1987 };
1988
1989 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1990 {
1991         struct btrfs_writepage_fixup *fixup;
1992         struct btrfs_ordered_extent *ordered;
1993         struct extent_state *cached_state = NULL;
1994         struct page *page;
1995         struct inode *inode;
1996         u64 page_start;
1997         u64 page_end;
1998         int ret;
1999
2000         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2001         page = fixup->page;
2002 again:
2003         lock_page(page);
2004         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2005                 ClearPageChecked(page);
2006                 goto out_page;
2007         }
2008
2009         inode = page->mapping->host;
2010         page_start = page_offset(page);
2011         page_end = page_offset(page) + PAGE_SIZE - 1;
2012
2013         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2014                          &cached_state);
2015
2016         /* already ordered? We're done */
2017         if (PagePrivate2(page))
2018                 goto out;
2019
2020         ordered = btrfs_lookup_ordered_range(inode, page_start,
2021                                         PAGE_SIZE);
2022         if (ordered) {
2023                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2024                                      page_end, &cached_state, GFP_NOFS);
2025                 unlock_page(page);
2026                 btrfs_start_ordered_extent(inode, ordered, 1);
2027                 btrfs_put_ordered_extent(ordered);
2028                 goto again;
2029         }
2030
2031         ret = btrfs_delalloc_reserve_space(inode, page_start,
2032                                            PAGE_SIZE);
2033         if (ret) {
2034                 mapping_set_error(page->mapping, ret);
2035                 end_extent_writepage(page, ret, page_start, page_end);
2036                 ClearPageChecked(page);
2037                 goto out;
2038          }
2039
2040         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
2041         ClearPageChecked(page);
2042         set_page_dirty(page);
2043 out:
2044         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2045                              &cached_state, GFP_NOFS);
2046 out_page:
2047         unlock_page(page);
2048         put_page(page);
2049         kfree(fixup);
2050 }
2051
2052 /*
2053  * There are a few paths in the higher layers of the kernel that directly
2054  * set the page dirty bit without asking the filesystem if it is a
2055  * good idea.  This causes problems because we want to make sure COW
2056  * properly happens and the data=ordered rules are followed.
2057  *
2058  * In our case any range that doesn't have the ORDERED bit set
2059  * hasn't been properly setup for IO.  We kick off an async process
2060  * to fix it up.  The async helper will wait for ordered extents, set
2061  * the delalloc bit and make it safe to write the page.
2062  */
2063 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2064 {
2065         struct inode *inode = page->mapping->host;
2066         struct btrfs_writepage_fixup *fixup;
2067         struct btrfs_root *root = BTRFS_I(inode)->root;
2068
2069         /* this page is properly in the ordered list */
2070         if (TestClearPagePrivate2(page))
2071                 return 0;
2072
2073         if (PageChecked(page))
2074                 return -EAGAIN;
2075
2076         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2077         if (!fixup)
2078                 return -EAGAIN;
2079
2080         SetPageChecked(page);
2081         get_page(page);
2082         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2083                         btrfs_writepage_fixup_worker, NULL, NULL);
2084         fixup->page = page;
2085         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
2086         return -EBUSY;
2087 }
2088
2089 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2090                                        struct inode *inode, u64 file_pos,
2091                                        u64 disk_bytenr, u64 disk_num_bytes,
2092                                        u64 num_bytes, u64 ram_bytes,
2093                                        u8 compression, u8 encryption,
2094                                        u16 other_encoding, int extent_type)
2095 {
2096         struct btrfs_root *root = BTRFS_I(inode)->root;
2097         struct btrfs_file_extent_item *fi;
2098         struct btrfs_path *path;
2099         struct extent_buffer *leaf;
2100         struct btrfs_key ins;
2101         int extent_inserted = 0;
2102         int ret;
2103
2104         path = btrfs_alloc_path();
2105         if (!path)
2106                 return -ENOMEM;
2107
2108         /*
2109          * we may be replacing one extent in the tree with another.
2110          * The new extent is pinned in the extent map, and we don't want
2111          * to drop it from the cache until it is completely in the btree.
2112          *
2113          * So, tell btrfs_drop_extents to leave this extent in the cache.
2114          * the caller is expected to unpin it and allow it to be merged
2115          * with the others.
2116          */
2117         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2118                                    file_pos + num_bytes, NULL, 0,
2119                                    1, sizeof(*fi), &extent_inserted);
2120         if (ret)
2121                 goto out;
2122
2123         if (!extent_inserted) {
2124                 ins.objectid = btrfs_ino(inode);
2125                 ins.offset = file_pos;
2126                 ins.type = BTRFS_EXTENT_DATA_KEY;
2127
2128                 path->leave_spinning = 1;
2129                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2130                                               sizeof(*fi));
2131                 if (ret)
2132                         goto out;
2133         }
2134         leaf = path->nodes[0];
2135         fi = btrfs_item_ptr(leaf, path->slots[0],
2136                             struct btrfs_file_extent_item);
2137         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2138         btrfs_set_file_extent_type(leaf, fi, extent_type);
2139         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2140         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2141         btrfs_set_file_extent_offset(leaf, fi, 0);
2142         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2143         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2144         btrfs_set_file_extent_compression(leaf, fi, compression);
2145         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2146         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2147
2148         btrfs_mark_buffer_dirty(leaf);
2149         btrfs_release_path(path);
2150
2151         inode_add_bytes(inode, num_bytes);
2152
2153         ins.objectid = disk_bytenr;
2154         ins.offset = disk_num_bytes;
2155         ins.type = BTRFS_EXTENT_ITEM_KEY;
2156         ret = btrfs_alloc_reserved_file_extent(trans, root,
2157                                         root->root_key.objectid,
2158                                         btrfs_ino(inode), file_pos,
2159                                         ram_bytes, &ins);
2160         /*
2161          * Release the reserved range from inode dirty range map, as it is
2162          * already moved into delayed_ref_head
2163          */
2164         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2165 out:
2166         btrfs_free_path(path);
2167
2168         return ret;
2169 }
2170
2171 /* snapshot-aware defrag */
2172 struct sa_defrag_extent_backref {
2173         struct rb_node node;
2174         struct old_sa_defrag_extent *old;
2175         u64 root_id;
2176         u64 inum;
2177         u64 file_pos;
2178         u64 extent_offset;
2179         u64 num_bytes;
2180         u64 generation;
2181 };
2182
2183 struct old_sa_defrag_extent {
2184         struct list_head list;
2185         struct new_sa_defrag_extent *new;
2186
2187         u64 extent_offset;
2188         u64 bytenr;
2189         u64 offset;
2190         u64 len;
2191         int count;
2192 };
2193
2194 struct new_sa_defrag_extent {
2195         struct rb_root root;
2196         struct list_head head;
2197         struct btrfs_path *path;
2198         struct inode *inode;
2199         u64 file_pos;
2200         u64 len;
2201         u64 bytenr;
2202         u64 disk_len;
2203         u8 compress_type;
2204 };
2205
2206 static int backref_comp(struct sa_defrag_extent_backref *b1,
2207                         struct sa_defrag_extent_backref *b2)
2208 {
2209         if (b1->root_id < b2->root_id)
2210                 return -1;
2211         else if (b1->root_id > b2->root_id)
2212                 return 1;
2213
2214         if (b1->inum < b2->inum)
2215                 return -1;
2216         else if (b1->inum > b2->inum)
2217                 return 1;
2218
2219         if (b1->file_pos < b2->file_pos)
2220                 return -1;
2221         else if (b1->file_pos > b2->file_pos)
2222                 return 1;
2223
2224         /*
2225          * [------------------------------] ===> (a range of space)
2226          *     |<--->|   |<---->| =============> (fs/file tree A)
2227          * |<---------------------------->| ===> (fs/file tree B)
2228          *
2229          * A range of space can refer to two file extents in one tree while
2230          * refer to only one file extent in another tree.
2231          *
2232          * So we may process a disk offset more than one time(two extents in A)
2233          * and locate at the same extent(one extent in B), then insert two same
2234          * backrefs(both refer to the extent in B).
2235          */
2236         return 0;
2237 }
2238
2239 static void backref_insert(struct rb_root *root,
2240                            struct sa_defrag_extent_backref *backref)
2241 {
2242         struct rb_node **p = &root->rb_node;
2243         struct rb_node *parent = NULL;
2244         struct sa_defrag_extent_backref *entry;
2245         int ret;
2246
2247         while (*p) {
2248                 parent = *p;
2249                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2250
2251                 ret = backref_comp(backref, entry);
2252                 if (ret < 0)
2253                         p = &(*p)->rb_left;
2254                 else
2255                         p = &(*p)->rb_right;
2256         }
2257
2258         rb_link_node(&backref->node, parent, p);
2259         rb_insert_color(&backref->node, root);
2260 }
2261
2262 /*
2263  * Note the backref might has changed, and in this case we just return 0.
2264  */
2265 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2266                                        void *ctx)
2267 {
2268         struct btrfs_file_extent_item *extent;
2269         struct btrfs_fs_info *fs_info;
2270         struct old_sa_defrag_extent *old = ctx;
2271         struct new_sa_defrag_extent *new = old->new;
2272         struct btrfs_path *path = new->path;
2273         struct btrfs_key key;
2274         struct btrfs_root *root;
2275         struct sa_defrag_extent_backref *backref;
2276         struct extent_buffer *leaf;
2277         struct inode *inode = new->inode;
2278         int slot;
2279         int ret;
2280         u64 extent_offset;
2281         u64 num_bytes;
2282
2283         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2284             inum == btrfs_ino(inode))
2285                 return 0;
2286
2287         key.objectid = root_id;
2288         key.type = BTRFS_ROOT_ITEM_KEY;
2289         key.offset = (u64)-1;
2290
2291         fs_info = BTRFS_I(inode)->root->fs_info;
2292         root = btrfs_read_fs_root_no_name(fs_info, &key);
2293         if (IS_ERR(root)) {
2294                 if (PTR_ERR(root) == -ENOENT)
2295                         return 0;
2296                 WARN_ON(1);
2297                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2298                          inum, offset, root_id);
2299                 return PTR_ERR(root);
2300         }
2301
2302         key.objectid = inum;
2303         key.type = BTRFS_EXTENT_DATA_KEY;
2304         if (offset > (u64)-1 << 32)
2305                 key.offset = 0;
2306         else
2307                 key.offset = offset;
2308
2309         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2310         if (WARN_ON(ret < 0))
2311                 return ret;
2312         ret = 0;
2313
2314         while (1) {
2315                 cond_resched();
2316
2317                 leaf = path->nodes[0];
2318                 slot = path->slots[0];
2319
2320                 if (slot >= btrfs_header_nritems(leaf)) {
2321                         ret = btrfs_next_leaf(root, path);
2322                         if (ret < 0) {
2323                                 goto out;
2324                         } else if (ret > 0) {
2325                                 ret = 0;
2326                                 goto out;
2327                         }
2328                         continue;
2329                 }
2330
2331                 path->slots[0]++;
2332
2333                 btrfs_item_key_to_cpu(leaf, &key, slot);
2334
2335                 if (key.objectid > inum)
2336                         goto out;
2337
2338                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2339                         continue;
2340
2341                 extent = btrfs_item_ptr(leaf, slot,
2342                                         struct btrfs_file_extent_item);
2343
2344                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2345                         continue;
2346
2347                 /*
2348                  * 'offset' refers to the exact key.offset,
2349                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2350                  * (key.offset - extent_offset).
2351                  */
2352                 if (key.offset != offset)
2353                         continue;
2354
2355                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2356                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2357
2358                 if (extent_offset >= old->extent_offset + old->offset +
2359                     old->len || extent_offset + num_bytes <=
2360                     old->extent_offset + old->offset)
2361                         continue;
2362                 break;
2363         }
2364
2365         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2366         if (!backref) {
2367                 ret = -ENOENT;
2368                 goto out;
2369         }
2370
2371         backref->root_id = root_id;
2372         backref->inum = inum;
2373         backref->file_pos = offset;
2374         backref->num_bytes = num_bytes;
2375         backref->extent_offset = extent_offset;
2376         backref->generation = btrfs_file_extent_generation(leaf, extent);
2377         backref->old = old;
2378         backref_insert(&new->root, backref);
2379         old->count++;
2380 out:
2381         btrfs_release_path(path);
2382         WARN_ON(ret);
2383         return ret;
2384 }
2385
2386 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2387                                    struct new_sa_defrag_extent *new)
2388 {
2389         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2390         struct old_sa_defrag_extent *old, *tmp;
2391         int ret;
2392
2393         new->path = path;
2394
2395         list_for_each_entry_safe(old, tmp, &new->head, list) {
2396                 ret = iterate_inodes_from_logical(old->bytenr +
2397                                                   old->extent_offset, fs_info,
2398                                                   path, record_one_backref,
2399                                                   old);
2400                 if (ret < 0 && ret != -ENOENT)
2401                         return false;
2402
2403                 /* no backref to be processed for this extent */
2404                 if (!old->count) {
2405                         list_del(&old->list);
2406                         kfree(old);
2407                 }
2408         }
2409
2410         if (list_empty(&new->head))
2411                 return false;
2412
2413         return true;
2414 }
2415
2416 static int relink_is_mergable(struct extent_buffer *leaf,
2417                               struct btrfs_file_extent_item *fi,
2418                               struct new_sa_defrag_extent *new)
2419 {
2420         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2421                 return 0;
2422
2423         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2424                 return 0;
2425
2426         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2427                 return 0;
2428
2429         if (btrfs_file_extent_encryption(leaf, fi) ||
2430             btrfs_file_extent_other_encoding(leaf, fi))
2431                 return 0;
2432
2433         return 1;
2434 }
2435
2436 /*
2437  * Note the backref might has changed, and in this case we just return 0.
2438  */
2439 static noinline int relink_extent_backref(struct btrfs_path *path,
2440                                  struct sa_defrag_extent_backref *prev,
2441                                  struct sa_defrag_extent_backref *backref)
2442 {
2443         struct btrfs_file_extent_item *extent;
2444         struct btrfs_file_extent_item *item;
2445         struct btrfs_ordered_extent *ordered;
2446         struct btrfs_trans_handle *trans;
2447         struct btrfs_fs_info *fs_info;
2448         struct btrfs_root *root;
2449         struct btrfs_key key;
2450         struct extent_buffer *leaf;
2451         struct old_sa_defrag_extent *old = backref->old;
2452         struct new_sa_defrag_extent *new = old->new;
2453         struct inode *src_inode = new->inode;
2454         struct inode *inode;
2455         struct extent_state *cached = NULL;
2456         int ret = 0;
2457         u64 start;
2458         u64 len;
2459         u64 lock_start;
2460         u64 lock_end;
2461         bool merge = false;
2462         int index;
2463
2464         if (prev && prev->root_id == backref->root_id &&
2465             prev->inum == backref->inum &&
2466             prev->file_pos + prev->num_bytes == backref->file_pos)
2467                 merge = true;
2468
2469         /* step 1: get root */
2470         key.objectid = backref->root_id;
2471         key.type = BTRFS_ROOT_ITEM_KEY;
2472         key.offset = (u64)-1;
2473
2474         fs_info = BTRFS_I(src_inode)->root->fs_info;
2475         index = srcu_read_lock(&fs_info->subvol_srcu);
2476
2477         root = btrfs_read_fs_root_no_name(fs_info, &key);
2478         if (IS_ERR(root)) {
2479                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2480                 if (PTR_ERR(root) == -ENOENT)
2481                         return 0;
2482                 return PTR_ERR(root);
2483         }
2484
2485         if (btrfs_root_readonly(root)) {
2486                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2487                 return 0;
2488         }
2489
2490         /* step 2: get inode */
2491         key.objectid = backref->inum;
2492         key.type = BTRFS_INODE_ITEM_KEY;
2493         key.offset = 0;
2494
2495         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2496         if (IS_ERR(inode)) {
2497                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2498                 return 0;
2499         }
2500
2501         srcu_read_unlock(&fs_info->subvol_srcu, index);
2502
2503         /* step 3: relink backref */
2504         lock_start = backref->file_pos;
2505         lock_end = backref->file_pos + backref->num_bytes - 1;
2506         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2507                          &cached);
2508
2509         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2510         if (ordered) {
2511                 btrfs_put_ordered_extent(ordered);
2512                 goto out_unlock;
2513         }
2514
2515         trans = btrfs_join_transaction(root);
2516         if (IS_ERR(trans)) {
2517                 ret = PTR_ERR(trans);
2518                 goto out_unlock;
2519         }
2520
2521         key.objectid = backref->inum;
2522         key.type = BTRFS_EXTENT_DATA_KEY;
2523         key.offset = backref->file_pos;
2524
2525         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2526         if (ret < 0) {
2527                 goto out_free_path;
2528         } else if (ret > 0) {
2529                 ret = 0;
2530                 goto out_free_path;
2531         }
2532
2533         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2534                                 struct btrfs_file_extent_item);
2535
2536         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2537             backref->generation)
2538                 goto out_free_path;
2539
2540         btrfs_release_path(path);
2541
2542         start = backref->file_pos;
2543         if (backref->extent_offset < old->extent_offset + old->offset)
2544                 start += old->extent_offset + old->offset -
2545                          backref->extent_offset;
2546
2547         len = min(backref->extent_offset + backref->num_bytes,
2548                   old->extent_offset + old->offset + old->len);
2549         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2550
2551         ret = btrfs_drop_extents(trans, root, inode, start,
2552                                  start + len, 1);
2553         if (ret)
2554                 goto out_free_path;
2555 again:
2556         key.objectid = btrfs_ino(inode);
2557         key.type = BTRFS_EXTENT_DATA_KEY;
2558         key.offset = start;
2559
2560         path->leave_spinning = 1;
2561         if (merge) {
2562                 struct btrfs_file_extent_item *fi;
2563                 u64 extent_len;
2564                 struct btrfs_key found_key;
2565
2566                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2567                 if (ret < 0)
2568                         goto out_free_path;
2569
2570                 path->slots[0]--;
2571                 leaf = path->nodes[0];
2572                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2573
2574                 fi = btrfs_item_ptr(leaf, path->slots[0],
2575                                     struct btrfs_file_extent_item);
2576                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2577
2578                 if (extent_len + found_key.offset == start &&
2579                     relink_is_mergable(leaf, fi, new)) {
2580                         btrfs_set_file_extent_num_bytes(leaf, fi,
2581                                                         extent_len + len);
2582                         btrfs_mark_buffer_dirty(leaf);
2583                         inode_add_bytes(inode, len);
2584
2585                         ret = 1;
2586                         goto out_free_path;
2587                 } else {
2588                         merge = false;
2589                         btrfs_release_path(path);
2590                         goto again;
2591                 }
2592         }
2593
2594         ret = btrfs_insert_empty_item(trans, root, path, &key,
2595                                         sizeof(*extent));
2596         if (ret) {
2597                 btrfs_abort_transaction(trans, root, ret);
2598                 goto out_free_path;
2599         }
2600
2601         leaf = path->nodes[0];
2602         item = btrfs_item_ptr(leaf, path->slots[0],
2603                                 struct btrfs_file_extent_item);
2604         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2605         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2606         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2607         btrfs_set_file_extent_num_bytes(leaf, item, len);
2608         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2609         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2610         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2611         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2612         btrfs_set_file_extent_encryption(leaf, item, 0);
2613         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2614
2615         btrfs_mark_buffer_dirty(leaf);
2616         inode_add_bytes(inode, len);
2617         btrfs_release_path(path);
2618
2619         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2620                         new->disk_len, 0,
2621                         backref->root_id, backref->inum,
2622                         new->file_pos); /* start - extent_offset */
2623         if (ret) {
2624                 btrfs_abort_transaction(trans, root, ret);
2625                 goto out_free_path;
2626         }
2627
2628         ret = 1;
2629 out_free_path:
2630         btrfs_release_path(path);
2631         path->leave_spinning = 0;
2632         btrfs_end_transaction(trans, root);
2633 out_unlock:
2634         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2635                              &cached, GFP_NOFS);
2636         iput(inode);
2637         return ret;
2638 }
2639
2640 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2641 {
2642         struct old_sa_defrag_extent *old, *tmp;
2643
2644         if (!new)
2645                 return;
2646
2647         list_for_each_entry_safe(old, tmp, &new->head, list) {
2648                 kfree(old);
2649         }
2650         kfree(new);
2651 }
2652
2653 static void relink_file_extents(struct new_sa_defrag_extent *new)
2654 {
2655         struct btrfs_path *path;
2656         struct sa_defrag_extent_backref *backref;
2657         struct sa_defrag_extent_backref *prev = NULL;
2658         struct inode *inode;
2659         struct btrfs_root *root;
2660         struct rb_node *node;
2661         int ret;
2662
2663         inode = new->inode;
2664         root = BTRFS_I(inode)->root;
2665
2666         path = btrfs_alloc_path();
2667         if (!path)
2668                 return;
2669
2670         if (!record_extent_backrefs(path, new)) {
2671                 btrfs_free_path(path);
2672                 goto out;
2673         }
2674         btrfs_release_path(path);
2675
2676         while (1) {
2677                 node = rb_first(&new->root);
2678                 if (!node)
2679                         break;
2680                 rb_erase(node, &new->root);
2681
2682                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2683
2684                 ret = relink_extent_backref(path, prev, backref);
2685                 WARN_ON(ret < 0);
2686
2687                 kfree(prev);
2688
2689                 if (ret == 1)
2690                         prev = backref;
2691                 else
2692                         prev = NULL;
2693                 cond_resched();
2694         }
2695         kfree(prev);
2696
2697         btrfs_free_path(path);
2698 out:
2699         free_sa_defrag_extent(new);
2700
2701         atomic_dec(&root->fs_info->defrag_running);
2702         wake_up(&root->fs_info->transaction_wait);
2703 }
2704
2705 static struct new_sa_defrag_extent *
2706 record_old_file_extents(struct inode *inode,
2707                         struct btrfs_ordered_extent *ordered)
2708 {
2709         struct btrfs_root *root = BTRFS_I(inode)->root;
2710         struct btrfs_path *path;
2711         struct btrfs_key key;
2712         struct old_sa_defrag_extent *old;
2713         struct new_sa_defrag_extent *new;
2714         int ret;
2715
2716         new = kmalloc(sizeof(*new), GFP_NOFS);
2717         if (!new)
2718                 return NULL;
2719
2720         new->inode = inode;
2721         new->file_pos = ordered->file_offset;
2722         new->len = ordered->len;
2723         new->bytenr = ordered->start;
2724         new->disk_len = ordered->disk_len;
2725         new->compress_type = ordered->compress_type;
2726         new->root = RB_ROOT;
2727         INIT_LIST_HEAD(&new->head);
2728
2729         path = btrfs_alloc_path();
2730         if (!path)
2731                 goto out_kfree;
2732
2733         key.objectid = btrfs_ino(inode);
2734         key.type = BTRFS_EXTENT_DATA_KEY;
2735         key.offset = new->file_pos;
2736
2737         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2738         if (ret < 0)
2739                 goto out_free_path;
2740         if (ret > 0 && path->slots[0] > 0)
2741                 path->slots[0]--;
2742
2743         /* find out all the old extents for the file range */
2744         while (1) {
2745                 struct btrfs_file_extent_item *extent;
2746                 struct extent_buffer *l;
2747                 int slot;
2748                 u64 num_bytes;
2749                 u64 offset;
2750                 u64 end;
2751                 u64 disk_bytenr;
2752                 u64 extent_offset;
2753
2754                 l = path->nodes[0];
2755                 slot = path->slots[0];
2756
2757                 if (slot >= btrfs_header_nritems(l)) {
2758                         ret = btrfs_next_leaf(root, path);
2759                         if (ret < 0)
2760                                 goto out_free_path;
2761                         else if (ret > 0)
2762                                 break;
2763                         continue;
2764                 }
2765
2766                 btrfs_item_key_to_cpu(l, &key, slot);
2767
2768                 if (key.objectid != btrfs_ino(inode))
2769                         break;
2770                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2771                         break;
2772                 if (key.offset >= new->file_pos + new->len)
2773                         break;
2774
2775                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2776
2777                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2778                 if (key.offset + num_bytes < new->file_pos)
2779                         goto next;
2780
2781                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2782                 if (!disk_bytenr)
2783                         goto next;
2784
2785                 extent_offset = btrfs_file_extent_offset(l, extent);
2786
2787                 old = kmalloc(sizeof(*old), GFP_NOFS);
2788                 if (!old)
2789                         goto out_free_path;
2790
2791                 offset = max(new->file_pos, key.offset);
2792                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2793
2794                 old->bytenr = disk_bytenr;
2795                 old->extent_offset = extent_offset;
2796                 old->offset = offset - key.offset;
2797                 old->len = end - offset;
2798                 old->new = new;
2799                 old->count = 0;
2800                 list_add_tail(&old->list, &new->head);
2801 next:
2802                 path->slots[0]++;
2803                 cond_resched();
2804         }
2805
2806         btrfs_free_path(path);
2807         atomic_inc(&root->fs_info->defrag_running);
2808
2809         return new;
2810
2811 out_free_path:
2812         btrfs_free_path(path);
2813 out_kfree:
2814         free_sa_defrag_extent(new);
2815         return NULL;
2816 }
2817
2818 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2819                                          u64 start, u64 len)
2820 {
2821         struct btrfs_block_group_cache *cache;
2822
2823         cache = btrfs_lookup_block_group(root->fs_info, start);
2824         ASSERT(cache);
2825
2826         spin_lock(&cache->lock);
2827         cache->delalloc_bytes -= len;
2828         spin_unlock(&cache->lock);
2829
2830         btrfs_put_block_group(cache);
2831 }
2832
2833 /* as ordered data IO finishes, this gets called so we can finish
2834  * an ordered extent if the range of bytes in the file it covers are
2835  * fully written.
2836  */
2837 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2838 {
2839         struct inode *inode = ordered_extent->inode;
2840         struct btrfs_root *root = BTRFS_I(inode)->root;
2841         struct btrfs_trans_handle *trans = NULL;
2842         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2843         struct extent_state *cached_state = NULL;
2844         struct new_sa_defrag_extent *new = NULL;
2845         int compress_type = 0;
2846         int ret = 0;
2847         u64 logical_len = ordered_extent->len;
2848         bool nolock;
2849         bool truncated = false;
2850
2851         nolock = btrfs_is_free_space_inode(inode);
2852
2853         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2854                 ret = -EIO;
2855                 goto out;
2856         }
2857
2858         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2859                                      ordered_extent->file_offset +
2860                                      ordered_extent->len - 1);
2861
2862         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2863                 truncated = true;
2864                 logical_len = ordered_extent->truncated_len;
2865                 /* Truncated the entire extent, don't bother adding */
2866                 if (!logical_len)
2867                         goto out;
2868         }
2869
2870         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2871                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2872
2873                 /*
2874                  * For mwrite(mmap + memset to write) case, we still reserve
2875                  * space for NOCOW range.
2876                  * As NOCOW won't cause a new delayed ref, just free the space
2877                  */
2878                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2879                                        ordered_extent->len);
2880                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2881                 if (nolock)
2882                         trans = btrfs_join_transaction_nolock(root);
2883                 else
2884                         trans = btrfs_join_transaction(root);
2885                 if (IS_ERR(trans)) {
2886                         ret = PTR_ERR(trans);
2887                         trans = NULL;
2888                         goto out;
2889                 }
2890                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2891                 ret = btrfs_update_inode_fallback(trans, root, inode);
2892                 if (ret) /* -ENOMEM or corruption */
2893                         btrfs_abort_transaction(trans, root, ret);
2894                 goto out;
2895         }
2896
2897         lock_extent_bits(io_tree, ordered_extent->file_offset,
2898                          ordered_extent->file_offset + ordered_extent->len - 1,
2899                          &cached_state);
2900
2901         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2902                         ordered_extent->file_offset + ordered_extent->len - 1,
2903                         EXTENT_DEFRAG, 1, cached_state);
2904         if (ret) {
2905                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2906                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2907                         /* the inode is shared */
2908                         new = record_old_file_extents(inode, ordered_extent);
2909
2910                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2911                         ordered_extent->file_offset + ordered_extent->len - 1,
2912                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2913         }
2914
2915         if (nolock)
2916                 trans = btrfs_join_transaction_nolock(root);
2917         else
2918                 trans = btrfs_join_transaction(root);
2919         if (IS_ERR(trans)) {
2920                 ret = PTR_ERR(trans);
2921                 trans = NULL;
2922                 goto out_unlock;
2923         }
2924
2925         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2926
2927         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2928                 compress_type = ordered_extent->compress_type;
2929         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2930                 BUG_ON(compress_type);
2931                 ret = btrfs_mark_extent_written(trans, inode,
2932                                                 ordered_extent->file_offset,
2933                                                 ordered_extent->file_offset +
2934                                                 logical_len);
2935         } else {
2936                 BUG_ON(root == root->fs_info->tree_root);
2937                 ret = insert_reserved_file_extent(trans, inode,
2938                                                 ordered_extent->file_offset,
2939                                                 ordered_extent->start,
2940                                                 ordered_extent->disk_len,
2941                                                 logical_len, logical_len,
2942                                                 compress_type, 0, 0,
2943                                                 BTRFS_FILE_EXTENT_REG);
2944                 if (!ret)
2945                         btrfs_release_delalloc_bytes(root,
2946                                                      ordered_extent->start,
2947                                                      ordered_extent->disk_len);
2948         }
2949         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2950                            ordered_extent->file_offset, ordered_extent->len,
2951                            trans->transid);
2952         if (ret < 0) {
2953                 btrfs_abort_transaction(trans, root, ret);
2954                 goto out_unlock;
2955         }
2956
2957         add_pending_csums(trans, inode, ordered_extent->file_offset,
2958                           &ordered_extent->list);
2959
2960         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2961         ret = btrfs_update_inode_fallback(trans, root, inode);
2962         if (ret) { /* -ENOMEM or corruption */
2963                 btrfs_abort_transaction(trans, root, ret);
2964                 goto out_unlock;
2965         }
2966         ret = 0;
2967 out_unlock:
2968         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2969                              ordered_extent->file_offset +
2970                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2971 out:
2972         if (root != root->fs_info->tree_root)
2973                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2974         if (trans)
2975                 btrfs_end_transaction(trans, root);
2976
2977         if (ret || truncated) {
2978                 u64 start, end;
2979
2980                 if (truncated)
2981                         start = ordered_extent->file_offset + logical_len;
2982                 else
2983                         start = ordered_extent->file_offset;
2984                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2985                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2986
2987                 /* Drop the cache for the part of the extent we didn't write. */
2988                 btrfs_drop_extent_cache(inode, start, end, 0);
2989
2990                 /*
2991                  * If the ordered extent had an IOERR or something else went
2992                  * wrong we need to return the space for this ordered extent
2993                  * back to the allocator.  We only free the extent in the
2994                  * truncated case if we didn't write out the extent at all.
2995                  */
2996                 if ((ret || !logical_len) &&
2997                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2998                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2999                         btrfs_free_reserved_extent(root, ordered_extent->start,
3000                                                    ordered_extent->disk_len, 1);
3001         }
3002
3003
3004         /*
3005          * This needs to be done to make sure anybody waiting knows we are done
3006          * updating everything for this ordered extent.
3007          */
3008         btrfs_remove_ordered_extent(inode, ordered_extent);
3009
3010         /* for snapshot-aware defrag */
3011         if (new) {
3012                 if (ret) {
3013                         free_sa_defrag_extent(new);
3014                         atomic_dec(&root->fs_info->defrag_running);
3015                 } else {
3016                         relink_file_extents(new);
3017                 }
3018         }
3019
3020         /* once for us */
3021         btrfs_put_ordered_extent(ordered_extent);
3022         /* once for the tree */
3023         btrfs_put_ordered_extent(ordered_extent);
3024
3025         return ret;
3026 }
3027
3028 static void finish_ordered_fn(struct btrfs_work *work)
3029 {
3030         struct btrfs_ordered_extent *ordered_extent;
3031         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3032         btrfs_finish_ordered_io(ordered_extent);
3033 }
3034
3035 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3036                                 struct extent_state *state, int uptodate)
3037 {
3038         struct inode *inode = page->mapping->host;
3039         struct btrfs_root *root = BTRFS_I(inode)->root;
3040         struct btrfs_ordered_extent *ordered_extent = NULL;
3041         struct btrfs_workqueue *wq;
3042         btrfs_work_func_t func;
3043
3044         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3045
3046         ClearPagePrivate2(page);
3047         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3048                                             end - start + 1, uptodate))
3049                 return 0;
3050
3051         if (btrfs_is_free_space_inode(inode)) {
3052                 wq = root->fs_info->endio_freespace_worker;
3053                 func = btrfs_freespace_write_helper;
3054         } else {
3055                 wq = root->fs_info->endio_write_workers;
3056                 func = btrfs_endio_write_helper;
3057         }
3058
3059         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3060                         NULL);
3061         btrfs_queue_work(wq, &ordered_extent->work);
3062
3063         return 0;
3064 }
3065
3066 static int __readpage_endio_check(struct inode *inode,
3067                                   struct btrfs_io_bio *io_bio,
3068                                   int icsum, struct page *page,
3069                                   int pgoff, u64 start, size_t len)
3070 {
3071         char *kaddr;
3072         u32 csum_expected;
3073         u32 csum = ~(u32)0;
3074
3075         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3076
3077         kaddr = kmap_atomic(page);
3078         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3079         btrfs_csum_final(csum, (char *)&csum);
3080         if (csum != csum_expected)
3081                 goto zeroit;
3082
3083         kunmap_atomic(kaddr);
3084         return 0;
3085 zeroit:
3086         btrfs_warn_rl(BTRFS_I(inode)->root->fs_info,
3087                 "csum failed ino %llu off %llu csum %u expected csum %u",
3088                            btrfs_ino(inode), start, csum, csum_expected);
3089         memset(kaddr + pgoff, 1, len);
3090         flush_dcache_page(page);
3091         kunmap_atomic(kaddr);
3092         if (csum_expected == 0)
3093                 return 0;
3094         return -EIO;
3095 }
3096
3097 /*
3098  * when reads are done, we need to check csums to verify the data is correct
3099  * if there's a match, we allow the bio to finish.  If not, the code in
3100  * extent_io.c will try to find good copies for us.
3101  */
3102 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3103                                       u64 phy_offset, struct page *page,
3104                                       u64 start, u64 end, int mirror)
3105 {
3106         size_t offset = start - page_offset(page);
3107         struct inode *inode = page->mapping->host;
3108         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3109         struct btrfs_root *root = BTRFS_I(inode)->root;
3110
3111         if (PageChecked(page)) {
3112                 ClearPageChecked(page);
3113                 return 0;
3114         }
3115
3116         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3117                 return 0;
3118
3119         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3120             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3121                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3122                 return 0;
3123         }
3124
3125         phy_offset >>= inode->i_sb->s_blocksize_bits;
3126         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3127                                       start, (size_t)(end - start + 1));
3128 }
3129
3130 void btrfs_add_delayed_iput(struct inode *inode)
3131 {
3132         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3133         struct btrfs_inode *binode = BTRFS_I(inode);
3134
3135         if (atomic_add_unless(&inode->i_count, -1, 1))
3136                 return;
3137
3138         spin_lock(&fs_info->delayed_iput_lock);
3139         if (binode->delayed_iput_count == 0) {
3140                 ASSERT(list_empty(&binode->delayed_iput));
3141                 list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3142         } else {
3143                 binode->delayed_iput_count++;
3144         }
3145         spin_unlock(&fs_info->delayed_iput_lock);
3146 }
3147
3148 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3149 {
3150         struct btrfs_fs_info *fs_info = root->fs_info;
3151
3152         spin_lock(&fs_info->delayed_iput_lock);
3153         while (!list_empty(&fs_info->delayed_iputs)) {
3154                 struct btrfs_inode *inode;
3155
3156                 inode = list_first_entry(&fs_info->delayed_iputs,
3157                                 struct btrfs_inode, delayed_iput);
3158                 if (inode->delayed_iput_count) {
3159                         inode->delayed_iput_count--;
3160                         list_move_tail(&inode->delayed_iput,
3161                                         &fs_info->delayed_iputs);
3162                 } else {
3163                         list_del_init(&inode->delayed_iput);
3164                 }
3165                 spin_unlock(&fs_info->delayed_iput_lock);
3166                 iput(&inode->vfs_inode);
3167                 spin_lock(&fs_info->delayed_iput_lock);
3168         }
3169         spin_unlock(&fs_info->delayed_iput_lock);
3170 }
3171
3172 /*
3173  * This is called in transaction commit time. If there are no orphan
3174  * files in the subvolume, it removes orphan item and frees block_rsv
3175  * structure.
3176  */
3177 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3178                               struct btrfs_root *root)
3179 {
3180         struct btrfs_block_rsv *block_rsv;
3181         int ret;
3182
3183         if (atomic_read(&root->orphan_inodes) ||
3184             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3185                 return;
3186
3187         spin_lock(&root->orphan_lock);
3188         if (atomic_read(&root->orphan_inodes)) {
3189                 spin_unlock(&root->orphan_lock);
3190                 return;
3191         }
3192
3193         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3194                 spin_unlock(&root->orphan_lock);
3195                 return;
3196         }
3197
3198         block_rsv = root->orphan_block_rsv;
3199         root->orphan_block_rsv = NULL;
3200         spin_unlock(&root->orphan_lock);
3201
3202         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3203             btrfs_root_refs(&root->root_item) > 0) {
3204                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3205                                             root->root_key.objectid);
3206                 if (ret)
3207                         btrfs_abort_transaction(trans, root, ret);
3208                 else
3209                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3210                                   &root->state);
3211         }
3212
3213         if (block_rsv) {
3214                 WARN_ON(block_rsv->size > 0);
3215                 btrfs_free_block_rsv(root, block_rsv);
3216         }
3217 }
3218
3219 /*
3220  * This creates an orphan entry for the given inode in case something goes
3221  * wrong in the middle of an unlink/truncate.
3222  *
3223  * NOTE: caller of this function should reserve 5 units of metadata for
3224  *       this function.
3225  */
3226 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3227 {
3228         struct btrfs_root *root = BTRFS_I(inode)->root;
3229         struct btrfs_block_rsv *block_rsv = NULL;
3230         int reserve = 0;
3231         int insert = 0;
3232         int ret;
3233
3234         if (!root->orphan_block_rsv) {
3235                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3236                 if (!block_rsv)
3237                         return -ENOMEM;
3238         }
3239
3240         spin_lock(&root->orphan_lock);
3241         if (!root->orphan_block_rsv) {
3242                 root->orphan_block_rsv = block_rsv;
3243         } else if (block_rsv) {
3244                 btrfs_free_block_rsv(root, block_rsv);
3245                 block_rsv = NULL;
3246         }
3247
3248         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3249                               &BTRFS_I(inode)->runtime_flags)) {
3250 #if 0
3251                 /*
3252                  * For proper ENOSPC handling, we should do orphan
3253                  * cleanup when mounting. But this introduces backward
3254                  * compatibility issue.
3255                  */
3256                 if (!xchg(&root->orphan_item_inserted, 1))
3257                         insert = 2;
3258                 else
3259                         insert = 1;
3260 #endif
3261                 insert = 1;
3262                 atomic_inc(&root->orphan_inodes);
3263         }
3264
3265         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3266                               &BTRFS_I(inode)->runtime_flags))
3267                 reserve = 1;
3268         spin_unlock(&root->orphan_lock);
3269
3270         /* grab metadata reservation from transaction handle */
3271         if (reserve) {
3272                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3273                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3274         }
3275
3276         /* insert an orphan item to track this unlinked/truncated file */
3277         if (insert >= 1) {
3278                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3279                 if (ret) {
3280                         atomic_dec(&root->orphan_inodes);
3281                         if (reserve) {
3282                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3283                                           &BTRFS_I(inode)->runtime_flags);
3284                                 btrfs_orphan_release_metadata(inode);
3285                         }
3286                         if (ret != -EEXIST) {
3287                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3288                                           &BTRFS_I(inode)->runtime_flags);
3289                                 btrfs_abort_transaction(trans, root, ret);
3290                                 return ret;
3291                         }
3292                 }
3293                 ret = 0;
3294         }
3295
3296         /* insert an orphan item to track subvolume contains orphan files */
3297         if (insert >= 2) {
3298                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3299                                                root->root_key.objectid);
3300                 if (ret && ret != -EEXIST) {
3301                         btrfs_abort_transaction(trans, root, ret);
3302                         return ret;
3303                 }
3304         }
3305         return 0;
3306 }
3307
3308 /*
3309  * We have done the truncate/delete so we can go ahead and remove the orphan
3310  * item for this particular inode.
3311  */
3312 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3313                             struct inode *inode)
3314 {
3315         struct btrfs_root *root = BTRFS_I(inode)->root;
3316         int delete_item = 0;
3317         int release_rsv = 0;
3318         int ret = 0;
3319
3320         spin_lock(&root->orphan_lock);
3321         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3322                                &BTRFS_I(inode)->runtime_flags))
3323                 delete_item = 1;
3324
3325         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3326                                &BTRFS_I(inode)->runtime_flags))
3327                 release_rsv = 1;
3328         spin_unlock(&root->orphan_lock);
3329
3330         if (delete_item) {
3331                 atomic_dec(&root->orphan_inodes);
3332                 if (trans)
3333                         ret = btrfs_del_orphan_item(trans, root,
3334                                                     btrfs_ino(inode));
3335         }
3336
3337         if (release_rsv)
3338                 btrfs_orphan_release_metadata(inode);
3339
3340         return ret;
3341 }
3342
3343 /*
3344  * this cleans up any orphans that may be left on the list from the last use
3345  * of this root.
3346  */
3347 int btrfs_orphan_cleanup(struct btrfs_root *root)
3348 {
3349         struct btrfs_path *path;
3350         struct extent_buffer *leaf;
3351         struct btrfs_key key, found_key;
3352         struct btrfs_trans_handle *trans;
3353         struct inode *inode;
3354         u64 last_objectid = 0;
3355         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3356
3357         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3358                 return 0;
3359
3360         path = btrfs_alloc_path();
3361         if (!path) {
3362                 ret = -ENOMEM;
3363                 goto out;
3364         }
3365         path->reada = READA_BACK;
3366
3367         key.objectid = BTRFS_ORPHAN_OBJECTID;
3368         key.type = BTRFS_ORPHAN_ITEM_KEY;
3369         key.offset = (u64)-1;
3370
3371         while (1) {
3372                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3373                 if (ret < 0)
3374                         goto out;
3375
3376                 /*
3377                  * if ret == 0 means we found what we were searching for, which
3378                  * is weird, but possible, so only screw with path if we didn't
3379                  * find the key and see if we have stuff that matches
3380                  */
3381                 if (ret > 0) {
3382                         ret = 0;
3383                         if (path->slots[0] == 0)
3384                                 break;
3385                         path->slots[0]--;
3386                 }
3387
3388                 /* pull out the item */
3389                 leaf = path->nodes[0];
3390                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3391
3392                 /* make sure the item matches what we want */
3393                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3394                         break;
3395                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3396                         break;
3397
3398                 /* release the path since we're done with it */
3399                 btrfs_release_path(path);
3400
3401                 /*
3402                  * this is where we are basically btrfs_lookup, without the
3403                  * crossing root thing.  we store the inode number in the
3404                  * offset of the orphan item.
3405                  */
3406
3407                 if (found_key.offset == last_objectid) {
3408                         btrfs_err(root->fs_info,
3409                                 "Error removing orphan entry, stopping orphan cleanup");
3410                         ret = -EINVAL;
3411                         goto out;
3412                 }
3413
3414                 last_objectid = found_key.offset;
3415
3416                 found_key.objectid = found_key.offset;
3417                 found_key.type = BTRFS_INODE_ITEM_KEY;
3418                 found_key.offset = 0;
3419                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3420                 ret = PTR_ERR_OR_ZERO(inode);
3421                 if (ret && ret != -ESTALE)
3422                         goto out;
3423
3424                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3425                         struct btrfs_root *dead_root;
3426                         struct btrfs_fs_info *fs_info = root->fs_info;
3427                         int is_dead_root = 0;
3428
3429                         /*
3430                          * this is an orphan in the tree root. Currently these
3431                          * could come from 2 sources:
3432                          *  a) a snapshot deletion in progress
3433                          *  b) a free space cache inode
3434                          * We need to distinguish those two, as the snapshot
3435                          * orphan must not get deleted.
3436                          * find_dead_roots already ran before us, so if this
3437                          * is a snapshot deletion, we should find the root
3438                          * in the dead_roots list
3439                          */
3440                         spin_lock(&fs_info->trans_lock);
3441                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3442                                             root_list) {
3443                                 if (dead_root->root_key.objectid ==
3444                                     found_key.objectid) {
3445                                         is_dead_root = 1;
3446                                         break;
3447                                 }
3448                         }
3449                         spin_unlock(&fs_info->trans_lock);
3450                         if (is_dead_root) {
3451                                 /* prevent this orphan from being found again */
3452                                 key.offset = found_key.objectid - 1;
3453                                 continue;
3454                         }
3455                 }
3456                 /*
3457                  * Inode is already gone but the orphan item is still there,
3458                  * kill the orphan item.
3459                  */
3460                 if (ret == -ESTALE) {
3461                         trans = btrfs_start_transaction(root, 1);
3462                         if (IS_ERR(trans)) {
3463                                 ret = PTR_ERR(trans);
3464                                 goto out;
3465                         }
3466                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3467                                 found_key.objectid);
3468                         ret = btrfs_del_orphan_item(trans, root,
3469                                                     found_key.objectid);
3470                         btrfs_end_transaction(trans, root);
3471                         if (ret)
3472                                 goto out;
3473                         continue;
3474                 }
3475
3476                 /*
3477                  * add this inode to the orphan list so btrfs_orphan_del does
3478                  * the proper thing when we hit it
3479                  */
3480                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3481                         &BTRFS_I(inode)->runtime_flags);
3482                 atomic_inc(&root->orphan_inodes);
3483
3484                 /* if we have links, this was a truncate, lets do that */
3485                 if (inode->i_nlink) {
3486                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3487                                 iput(inode);
3488                                 continue;
3489                         }
3490                         nr_truncate++;
3491
3492                         /* 1 for the orphan item deletion. */
3493                         trans = btrfs_start_transaction(root, 1);
3494                         if (IS_ERR(trans)) {
3495                                 iput(inode);
3496                                 ret = PTR_ERR(trans);
3497                                 goto out;
3498                         }
3499                         ret = btrfs_orphan_add(trans, inode);
3500                         btrfs_end_transaction(trans, root);
3501                         if (ret) {
3502                                 iput(inode);
3503                                 goto out;
3504                         }
3505
3506                         ret = btrfs_truncate(inode);
3507                         if (ret)
3508                                 btrfs_orphan_del(NULL, inode);
3509                 } else {
3510                         nr_unlink++;
3511                 }
3512
3513                 /* this will do delete_inode and everything for us */
3514                 iput(inode);
3515                 if (ret)
3516                         goto out;
3517         }
3518         /* release the path since we're done with it */
3519         btrfs_release_path(path);
3520
3521         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3522
3523         if (root->orphan_block_rsv)
3524                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3525                                         (u64)-1);
3526
3527         if (root->orphan_block_rsv ||
3528             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3529                 trans = btrfs_join_transaction(root);
3530                 if (!IS_ERR(trans))
3531                         btrfs_end_transaction(trans, root);
3532         }
3533
3534         if (nr_unlink)
3535                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3536         if (nr_truncate)
3537                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3538
3539 out:
3540         if (ret)
3541                 btrfs_err(root->fs_info,
3542                         "could not do orphan cleanup %d", ret);
3543         btrfs_free_path(path);
3544         return ret;
3545 }
3546
3547 /*
3548  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3549  * don't find any xattrs, we know there can't be any acls.
3550  *
3551  * slot is the slot the inode is in, objectid is the objectid of the inode
3552  */
3553 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3554                                           int slot, u64 objectid,
3555                                           int *first_xattr_slot)
3556 {
3557         u32 nritems = btrfs_header_nritems(leaf);
3558         struct btrfs_key found_key;
3559         static u64 xattr_access = 0;
3560         static u64 xattr_default = 0;
3561         int scanned = 0;
3562
3563         if (!xattr_access) {
3564                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3565                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3566                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3567                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3568         }
3569
3570         slot++;
3571         *first_xattr_slot = -1;
3572         while (slot < nritems) {
3573                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3574
3575                 /* we found a different objectid, there must not be acls */
3576                 if (found_key.objectid != objectid)
3577                         return 0;
3578
3579                 /* we found an xattr, assume we've got an acl */
3580                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3581                         if (*first_xattr_slot == -1)
3582                                 *first_xattr_slot = slot;
3583                         if (found_key.offset == xattr_access ||
3584                             found_key.offset == xattr_default)
3585                                 return 1;
3586                 }
3587
3588                 /*
3589                  * we found a key greater than an xattr key, there can't
3590                  * be any acls later on
3591                  */
3592                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3593                         return 0;
3594
3595                 slot++;
3596                 scanned++;
3597
3598                 /*
3599                  * it goes inode, inode backrefs, xattrs, extents,
3600                  * so if there are a ton of hard links to an inode there can
3601                  * be a lot of backrefs.  Don't waste time searching too hard,
3602                  * this is just an optimization
3603                  */
3604                 if (scanned >= 8)
3605                         break;
3606         }
3607         /* we hit the end of the leaf before we found an xattr or
3608          * something larger than an xattr.  We have to assume the inode
3609          * has acls
3610          */
3611         if (*first_xattr_slot == -1)
3612                 *first_xattr_slot = slot;
3613         return 1;
3614 }
3615
3616 /*
3617  * read an inode from the btree into the in-memory inode
3618  */
3619 static void btrfs_read_locked_inode(struct inode *inode)
3620 {
3621         struct btrfs_path *path;
3622         struct extent_buffer *leaf;
3623         struct btrfs_inode_item *inode_item;
3624         struct btrfs_root *root = BTRFS_I(inode)->root;
3625         struct btrfs_key location;
3626         unsigned long ptr;
3627         int maybe_acls;
3628         u32 rdev;
3629         int ret;
3630         bool filled = false;
3631         int first_xattr_slot;
3632
3633         ret = btrfs_fill_inode(inode, &rdev);
3634         if (!ret)
3635                 filled = true;
3636
3637         path = btrfs_alloc_path();
3638         if (!path)
3639                 goto make_bad;
3640
3641         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3642
3643         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3644         if (ret)
3645                 goto make_bad;
3646
3647         leaf = path->nodes[0];
3648
3649         if (filled)
3650                 goto cache_index;
3651
3652         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3653                                     struct btrfs_inode_item);
3654         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3655         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3656         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3657         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3658         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3659
3660         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3661         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3662
3663         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3664         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3665
3666         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3667         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3668
3669         BTRFS_I(inode)->i_otime.tv_sec =
3670                 btrfs_timespec_sec(leaf, &inode_item->otime);
3671         BTRFS_I(inode)->i_otime.tv_nsec =
3672                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3673
3674         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3675         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3676         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3677
3678         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3679         inode->i_generation = BTRFS_I(inode)->generation;
3680         inode->i_rdev = 0;
3681         rdev = btrfs_inode_rdev(leaf, inode_item);
3682
3683         BTRFS_I(inode)->index_cnt = (u64)-1;
3684         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3685
3686 cache_index:
3687         /*
3688          * If we were modified in the current generation and evicted from memory
3689          * and then re-read we need to do a full sync since we don't have any
3690          * idea about which extents were modified before we were evicted from
3691          * cache.
3692          *
3693          * This is required for both inode re-read from disk and delayed inode
3694          * in delayed_nodes_tree.
3695          */
3696         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3697                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3698                         &BTRFS_I(inode)->runtime_flags);
3699
3700         /*
3701          * We don't persist the id of the transaction where an unlink operation
3702          * against the inode was last made. So here we assume the inode might
3703          * have been evicted, and therefore the exact value of last_unlink_trans
3704          * lost, and set it to last_trans to avoid metadata inconsistencies
3705          * between the inode and its parent if the inode is fsync'ed and the log
3706          * replayed. For example, in the scenario:
3707          *
3708          * touch mydir/foo
3709          * ln mydir/foo mydir/bar
3710          * sync
3711          * unlink mydir/bar
3712          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3713          * xfs_io -c fsync mydir/foo
3714          * <power failure>
3715          * mount fs, triggers fsync log replay
3716          *
3717          * We must make sure that when we fsync our inode foo we also log its
3718          * parent inode, otherwise after log replay the parent still has the
3719          * dentry with the "bar" name but our inode foo has a link count of 1
3720          * and doesn't have an inode ref with the name "bar" anymore.
3721          *
3722          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3723          * but it guarantees correctness at the expense of occasional full
3724          * transaction commits on fsync if our inode is a directory, or if our
3725          * inode is not a directory, logging its parent unnecessarily.
3726          */
3727         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3728
3729         path->slots[0]++;
3730         if (inode->i_nlink != 1 ||
3731             path->slots[0] >= btrfs_header_nritems(leaf))
3732                 goto cache_acl;
3733
3734         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3735         if (location.objectid != btrfs_ino(inode))
3736                 goto cache_acl;
3737
3738         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3739         if (location.type == BTRFS_INODE_REF_KEY) {
3740                 struct btrfs_inode_ref *ref;
3741
3742                 ref = (struct btrfs_inode_ref *)ptr;
3743                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3744         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3745                 struct btrfs_inode_extref *extref;
3746
3747                 extref = (struct btrfs_inode_extref *)ptr;
3748                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3749                                                                      extref);
3750         }
3751 cache_acl:
3752         /*
3753          * try to precache a NULL acl entry for files that don't have
3754          * any xattrs or acls
3755          */
3756         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3757                                            btrfs_ino(inode), &first_xattr_slot);
3758         if (first_xattr_slot != -1) {
3759                 path->slots[0] = first_xattr_slot;
3760                 ret = btrfs_load_inode_props(inode, path);
3761                 if (ret)
3762                         btrfs_err(root->fs_info,
3763                                   "error loading props for ino %llu (root %llu): %d",
3764                                   btrfs_ino(inode),
3765                                   root->root_key.objectid, ret);
3766         }
3767         btrfs_free_path(path);
3768
3769         if (!maybe_acls)
3770                 cache_no_acl(inode);
3771
3772         switch (inode->i_mode & S_IFMT) {
3773         case S_IFREG:
3774                 inode->i_mapping->a_ops = &btrfs_aops;
3775                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3776                 inode->i_fop = &btrfs_file_operations;
3777                 inode->i_op = &btrfs_file_inode_operations;
3778                 break;
3779         case S_IFDIR:
3780                 inode->i_fop = &btrfs_dir_file_operations;
3781                 if (root == root->fs_info->tree_root)
3782                         inode->i_op = &btrfs_dir_ro_inode_operations;
3783                 else
3784                         inode->i_op = &btrfs_dir_inode_operations;
3785                 break;
3786         case S_IFLNK:
3787                 inode->i_op = &btrfs_symlink_inode_operations;
3788                 inode_nohighmem(inode);
3789                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3790                 break;
3791         default:
3792                 inode->i_op = &btrfs_special_inode_operations;
3793                 init_special_inode(inode, inode->i_mode, rdev);
3794                 break;
3795         }
3796
3797         btrfs_update_iflags(inode);
3798         return;
3799
3800 make_bad:
3801         btrfs_free_path(path);
3802         make_bad_inode(inode);
3803 }
3804
3805 /*
3806  * given a leaf and an inode, copy the inode fields into the leaf
3807  */
3808 static void fill_inode_item(struct btrfs_trans_handle *trans,
3809                             struct extent_buffer *leaf,
3810                             struct btrfs_inode_item *item,
3811                             struct inode *inode)
3812 {
3813         struct btrfs_map_token token;
3814
3815         btrfs_init_map_token(&token);
3816
3817         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3818         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3819         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3820                                    &token);
3821         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3822         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3823
3824         btrfs_set_token_timespec_sec(leaf, &item->atime,
3825                                      inode->i_atime.tv_sec, &token);
3826         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3827                                       inode->i_atime.tv_nsec, &token);
3828
3829         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3830                                      inode->i_mtime.tv_sec, &token);
3831         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3832                                       inode->i_mtime.tv_nsec, &token);
3833
3834         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3835                                      inode->i_ctime.tv_sec, &token);
3836         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3837                                       inode->i_ctime.tv_nsec, &token);
3838
3839         btrfs_set_token_timespec_sec(leaf, &item->otime,
3840                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3841         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3842                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3843
3844         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3845                                      &token);
3846         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3847                                          &token);
3848         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3849         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3850         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3851         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3852         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3853 }
3854
3855 /*
3856  * copy everything in the in-memory inode into the btree.
3857  */
3858 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3859                                 struct btrfs_root *root, struct inode *inode)
3860 {
3861         struct btrfs_inode_item *inode_item;
3862         struct btrfs_path *path;
3863         struct extent_buffer *leaf;
3864         int ret;
3865
3866         path = btrfs_alloc_path();
3867         if (!path)
3868                 return -ENOMEM;
3869
3870         path->leave_spinning = 1;
3871         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3872                                  1);
3873         if (ret) {
3874                 if (ret > 0)
3875                         ret = -ENOENT;
3876                 goto failed;
3877         }
3878
3879         leaf = path->nodes[0];
3880         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3881                                     struct btrfs_inode_item);
3882
3883         fill_inode_item(trans, leaf, inode_item, inode);
3884         btrfs_mark_buffer_dirty(leaf);
3885         btrfs_set_inode_last_trans(trans, inode);
3886         ret = 0;
3887 failed:
3888         btrfs_free_path(path);
3889         return ret;
3890 }
3891
3892 /*
3893  * copy everything in the in-memory inode into the btree.
3894  */
3895 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3896                                 struct btrfs_root *root, struct inode *inode)
3897 {
3898         int ret;
3899
3900         /*
3901          * If the inode is a free space inode, we can deadlock during commit
3902          * if we put it into the delayed code.
3903          *
3904          * The data relocation inode should also be directly updated
3905          * without delay
3906          */
3907         if (!btrfs_is_free_space_inode(inode)
3908             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3909             && !root->fs_info->log_root_recovering) {
3910                 btrfs_update_root_times(trans, root);
3911
3912                 ret = btrfs_delayed_update_inode(trans, root, inode);
3913                 if (!ret)
3914                         btrfs_set_inode_last_trans(trans, inode);
3915                 return ret;
3916         }
3917
3918         return btrfs_update_inode_item(trans, root, inode);
3919 }
3920
3921 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3922                                          struct btrfs_root *root,
3923                                          struct inode *inode)
3924 {
3925         int ret;
3926
3927         ret = btrfs_update_inode(trans, root, inode);
3928         if (ret == -ENOSPC)
3929                 return btrfs_update_inode_item(trans, root, inode);
3930         return ret;
3931 }
3932
3933 /*
3934  * unlink helper that gets used here in inode.c and in the tree logging
3935  * recovery code.  It remove a link in a directory with a given name, and
3936  * also drops the back refs in the inode to the directory
3937  */
3938 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3939                                 struct btrfs_root *root,
3940                                 struct inode *dir, struct inode *inode,
3941                                 const char *name, int name_len)
3942 {
3943         struct btrfs_path *path;
3944         int ret = 0;
3945         struct extent_buffer *leaf;
3946         struct btrfs_dir_item *di;
3947         struct btrfs_key key;
3948         u64 index;
3949         u64 ino = btrfs_ino(inode);
3950         u64 dir_ino = btrfs_ino(dir);
3951
3952         path = btrfs_alloc_path();
3953         if (!path) {
3954                 ret = -ENOMEM;
3955                 goto out;
3956         }
3957
3958         path->leave_spinning = 1;
3959         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3960                                     name, name_len, -1);
3961         if (IS_ERR(di)) {
3962                 ret = PTR_ERR(di);
3963                 goto err;
3964         }
3965         if (!di) {
3966                 ret = -ENOENT;
3967                 goto err;
3968         }
3969         leaf = path->nodes[0];
3970         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3971         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3972         if (ret)
3973                 goto err;
3974         btrfs_release_path(path);
3975
3976         /*
3977          * If we don't have dir index, we have to get it by looking up
3978          * the inode ref, since we get the inode ref, remove it directly,
3979          * it is unnecessary to do delayed deletion.
3980          *
3981          * But if we have dir index, needn't search inode ref to get it.
3982          * Since the inode ref is close to the inode item, it is better
3983          * that we delay to delete it, and just do this deletion when
3984          * we update the inode item.
3985          */
3986         if (BTRFS_I(inode)->dir_index) {
3987                 ret = btrfs_delayed_delete_inode_ref(inode);
3988                 if (!ret) {
3989                         index = BTRFS_I(inode)->dir_index;
3990                         goto skip_backref;
3991                 }
3992         }
3993
3994         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3995                                   dir_ino, &index);
3996         if (ret) {
3997                 btrfs_info(root->fs_info,
3998                         "failed to delete reference to %.*s, inode %llu parent %llu",
3999                         name_len, name, ino, dir_ino);
4000                 btrfs_abort_transaction(trans, root, ret);
4001                 goto err;
4002         }
4003 skip_backref:
4004         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4005         if (ret) {
4006                 btrfs_abort_transaction(trans, root, ret);
4007                 goto err;
4008         }
4009
4010         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
4011                                          inode, dir_ino);
4012         if (ret != 0 && ret != -ENOENT) {
4013                 btrfs_abort_transaction(trans, root, ret);
4014                 goto err;
4015         }
4016
4017         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
4018                                            dir, index);
4019         if (ret == -ENOENT)
4020                 ret = 0;
4021         else if (ret)
4022                 btrfs_abort_transaction(trans, root, ret);
4023 err:
4024         btrfs_free_path(path);
4025         if (ret)
4026                 goto out;
4027
4028         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4029         inode_inc_iversion(inode);
4030         inode_inc_iversion(dir);
4031         inode->i_ctime = dir->i_mtime =
4032                 dir->i_ctime = current_fs_time(inode->i_sb);
4033         ret = btrfs_update_inode(trans, root, dir);
4034 out:
4035         return ret;
4036 }
4037
4038 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4039                        struct btrfs_root *root,
4040                        struct inode *dir, struct inode *inode,
4041                        const char *name, int name_len)
4042 {
4043         int ret;
4044         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4045         if (!ret) {
4046                 drop_nlink(inode);
4047                 ret = btrfs_update_inode(trans, root, inode);
4048         }
4049         return ret;
4050 }
4051
4052 /*
4053  * helper to start transaction for unlink and rmdir.
4054  *
4055  * unlink and rmdir are special in btrfs, they do not always free space, so
4056  * if we cannot make our reservations the normal way try and see if there is
4057  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4058  * allow the unlink to occur.
4059  */
4060 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4061 {
4062         struct btrfs_root *root = BTRFS_I(dir)->root;
4063
4064         /*
4065          * 1 for the possible orphan item
4066          * 1 for the dir item
4067          * 1 for the dir index
4068          * 1 for the inode ref
4069          * 1 for the inode
4070          */
4071         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4072 }
4073
4074 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4075 {
4076         struct btrfs_root *root = BTRFS_I(dir)->root;
4077         struct btrfs_trans_handle *trans;
4078         struct inode *inode = d_inode(dentry);
4079         int ret;
4080
4081         trans = __unlink_start_trans(dir);
4082         if (IS_ERR(trans))
4083                 return PTR_ERR(trans);
4084
4085         btrfs_record_unlink_dir(trans, dir, d_inode(dentry), 0);
4086
4087         ret = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4088                                  dentry->d_name.name, dentry->d_name.len);
4089         if (ret)
4090                 goto out;
4091
4092         if (inode->i_nlink == 0) {
4093                 ret = btrfs_orphan_add(trans, inode);
4094                 if (ret)
4095                         goto out;
4096         }
4097
4098 out:
4099         btrfs_end_transaction(trans, root);
4100         btrfs_btree_balance_dirty(root);
4101         return ret;
4102 }
4103
4104 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4105                         struct btrfs_root *root,
4106                         struct inode *dir, u64 objectid,
4107                         const char *name, int name_len)
4108 {
4109         struct btrfs_path *path;
4110         struct extent_buffer *leaf;
4111         struct btrfs_dir_item *di;
4112         struct btrfs_key key;
4113         u64 index;
4114         int ret;
4115         u64 dir_ino = btrfs_ino(dir);
4116
4117         path = btrfs_alloc_path();
4118         if (!path)
4119                 return -ENOMEM;
4120
4121         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4122                                    name, name_len, -1);
4123         if (IS_ERR_OR_NULL(di)) {
4124                 if (!di)
4125                         ret = -ENOENT;
4126                 else
4127                         ret = PTR_ERR(di);
4128                 goto out;
4129         }
4130
4131         leaf = path->nodes[0];
4132         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4133         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4134         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4135         if (ret) {
4136                 btrfs_abort_transaction(trans, root, ret);
4137                 goto out;
4138         }
4139         btrfs_release_path(path);
4140
4141         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4142                                  objectid, root->root_key.objectid,
4143                                  dir_ino, &index, name, name_len);
4144         if (ret < 0) {
4145                 if (ret != -ENOENT) {
4146                         btrfs_abort_transaction(trans, root, ret);
4147                         goto out;
4148                 }
4149                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4150                                                  name, name_len);
4151                 if (IS_ERR_OR_NULL(di)) {
4152                         if (!di)
4153                                 ret = -ENOENT;
4154                         else
4155                                 ret = PTR_ERR(di);
4156                         btrfs_abort_transaction(trans, root, ret);
4157                         goto out;
4158                 }
4159
4160                 leaf = path->nodes[0];
4161                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4162                 btrfs_release_path(path);
4163                 index = key.offset;
4164         }
4165         btrfs_release_path(path);
4166
4167         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4168         if (ret) {
4169                 btrfs_abort_transaction(trans, root, ret);
4170                 goto out;
4171         }
4172
4173         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4174         inode_inc_iversion(dir);
4175         dir->i_mtime = dir->i_ctime = current_fs_time(dir->i_sb);
4176         ret = btrfs_update_inode_fallback(trans, root, dir);
4177         if (ret)
4178                 btrfs_abort_transaction(trans, root, ret);
4179 out:
4180         btrfs_free_path(path);
4181         return ret;
4182 }
4183
4184 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4185 {
4186         struct inode *inode = d_inode(dentry);
4187         int err = 0;
4188         struct btrfs_root *root = BTRFS_I(dir)->root;
4189         struct btrfs_trans_handle *trans;
4190
4191         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4192                 return -ENOTEMPTY;
4193         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4194                 return -EPERM;
4195
4196         trans = __unlink_start_trans(dir);
4197         if (IS_ERR(trans))
4198                 return PTR_ERR(trans);
4199
4200         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4201                 err = btrfs_unlink_subvol(trans, root, dir,
4202                                           BTRFS_I(inode)->location.objectid,
4203                                           dentry->d_name.name,
4204                                           dentry->d_name.len);
4205                 goto out;
4206         }
4207
4208         err = btrfs_orphan_add(trans, inode);
4209         if (err)
4210                 goto out;
4211
4212         /* now the directory is empty */
4213         err = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4214                                  dentry->d_name.name, dentry->d_name.len);
4215         if (!err)
4216                 btrfs_i_size_write(inode, 0);
4217 out:
4218         btrfs_end_transaction(trans, root);
4219         btrfs_btree_balance_dirty(root);
4220
4221         return err;
4222 }
4223
4224 static int truncate_space_check(struct btrfs_trans_handle *trans,
4225                                 struct btrfs_root *root,
4226                                 u64 bytes_deleted)
4227 {
4228         int ret;
4229
4230         /*
4231          * This is only used to apply pressure to the enospc system, we don't
4232          * intend to use this reservation at all.
4233          */
4234         bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
4235         bytes_deleted *= root->nodesize;
4236         ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
4237                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4238         if (!ret) {
4239                 trace_btrfs_space_reservation(root->fs_info, "transaction",
4240                                               trans->transid,
4241                                               bytes_deleted, 1);
4242                 trans->bytes_reserved += bytes_deleted;
4243         }
4244         return ret;
4245
4246 }
4247
4248 static int truncate_inline_extent(struct inode *inode,
4249                                   struct btrfs_path *path,
4250                                   struct btrfs_key *found_key,
4251                                   const u64 item_end,
4252                                   const u64 new_size)
4253 {
4254         struct extent_buffer *leaf = path->nodes[0];
4255         int slot = path->slots[0];
4256         struct btrfs_file_extent_item *fi;
4257         u32 size = (u32)(new_size - found_key->offset);
4258         struct btrfs_root *root = BTRFS_I(inode)->root;
4259
4260         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4261
4262         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4263                 loff_t offset = new_size;
4264                 loff_t page_end = ALIGN(offset, PAGE_SIZE);
4265
4266                 /*
4267                  * Zero out the remaining of the last page of our inline extent,
4268                  * instead of directly truncating our inline extent here - that
4269                  * would be much more complex (decompressing all the data, then
4270                  * compressing the truncated data, which might be bigger than
4271                  * the size of the inline extent, resize the extent, etc).
4272                  * We release the path because to get the page we might need to
4273                  * read the extent item from disk (data not in the page cache).
4274                  */
4275                 btrfs_release_path(path);
4276                 return btrfs_truncate_block(inode, offset, page_end - offset,
4277                                         0);
4278         }
4279
4280         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4281         size = btrfs_file_extent_calc_inline_size(size);
4282         btrfs_truncate_item(root, path, size, 1);
4283
4284         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4285                 inode_sub_bytes(inode, item_end + 1 - new_size);
4286
4287         return 0;
4288 }
4289
4290 /*
4291  * this can truncate away extent items, csum items and directory items.
4292  * It starts at a high offset and removes keys until it can't find
4293  * any higher than new_size
4294  *
4295  * csum items that cross the new i_size are truncated to the new size
4296  * as well.
4297  *
4298  * min_type is the minimum key type to truncate down to.  If set to 0, this
4299  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4300  */
4301 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4302                                struct btrfs_root *root,
4303                                struct inode *inode,
4304                                u64 new_size, u32 min_type)
4305 {
4306         struct btrfs_path *path;
4307         struct extent_buffer *leaf;
4308         struct btrfs_file_extent_item *fi;
4309         struct btrfs_key key;
4310         struct btrfs_key found_key;
4311         u64 extent_start = 0;
4312         u64 extent_num_bytes = 0;
4313         u64 extent_offset = 0;
4314         u64 item_end = 0;
4315         u64 last_size = new_size;
4316         u32 found_type = (u8)-1;
4317         int found_extent;
4318         int del_item;
4319         int pending_del_nr = 0;
4320         int pending_del_slot = 0;
4321         int extent_type = -1;
4322         int ret;
4323         int err = 0;
4324         u64 ino = btrfs_ino(inode);
4325         u64 bytes_deleted = 0;
4326         bool be_nice = 0;
4327         bool should_throttle = 0;
4328         bool should_end = 0;
4329
4330         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4331
4332         /*
4333          * for non-free space inodes and ref cows, we want to back off from
4334          * time to time
4335          */
4336         if (!btrfs_is_free_space_inode(inode) &&
4337             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4338                 be_nice = 1;
4339
4340         path = btrfs_alloc_path();
4341         if (!path)
4342                 return -ENOMEM;
4343         path->reada = READA_BACK;
4344
4345         /*
4346          * We want to drop from the next block forward in case this new size is
4347          * not block aligned since we will be keeping the last block of the
4348          * extent just the way it is.
4349          */
4350         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4351             root == root->fs_info->tree_root)
4352                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4353                                         root->sectorsize), (u64)-1, 0);
4354
4355         /*
4356          * This function is also used to drop the items in the log tree before
4357          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4358          * it is used to drop the loged items. So we shouldn't kill the delayed
4359          * items.
4360          */
4361         if (min_type == 0 && root == BTRFS_I(inode)->root)
4362                 btrfs_kill_delayed_inode_items(inode);
4363
4364         key.objectid = ino;
4365         key.offset = (u64)-1;
4366         key.type = (u8)-1;
4367
4368 search_again:
4369         /*
4370          * with a 16K leaf size and 128MB extents, you can actually queue
4371          * up a huge file in a single leaf.  Most of the time that
4372          * bytes_deleted is > 0, it will be huge by the time we get here
4373          */
4374         if (be_nice && bytes_deleted > SZ_32M) {
4375                 if (btrfs_should_end_transaction(trans, root)) {
4376                         err = -EAGAIN;
4377                         goto error;
4378                 }
4379         }
4380
4381
4382         path->leave_spinning = 1;
4383         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4384         if (ret < 0) {
4385                 err = ret;
4386                 goto out;
4387         }
4388
4389         if (ret > 0) {
4390                 /* there are no items in the tree for us to truncate, we're
4391                  * done
4392                  */
4393                 if (path->slots[0] == 0)
4394                         goto out;
4395                 path->slots[0]--;
4396         }
4397
4398         while (1) {
4399                 fi = NULL;
4400                 leaf = path->nodes[0];
4401                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4402                 found_type = found_key.type;
4403
4404                 if (found_key.objectid != ino)
4405                         break;
4406
4407                 if (found_type < min_type)
4408                         break;
4409
4410                 item_end = found_key.offset;
4411                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4412                         fi = btrfs_item_ptr(leaf, path->slots[0],
4413                                             struct btrfs_file_extent_item);
4414                         extent_type = btrfs_file_extent_type(leaf, fi);
4415                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4416                                 item_end +=
4417                                     btrfs_file_extent_num_bytes(leaf, fi);
4418                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4419                                 item_end += btrfs_file_extent_inline_len(leaf,
4420                                                          path->slots[0], fi);
4421                         }
4422                         item_end--;
4423                 }
4424                 if (found_type > min_type) {
4425                         del_item = 1;
4426                 } else {
4427                         if (item_end < new_size)
4428                                 break;
4429                         if (found_key.offset >= new_size)
4430                                 del_item = 1;
4431                         else
4432                                 del_item = 0;
4433                 }
4434                 found_extent = 0;
4435                 /* FIXME, shrink the extent if the ref count is only 1 */
4436                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4437                         goto delete;
4438
4439                 if (del_item)
4440                         last_size = found_key.offset;
4441                 else
4442                         last_size = new_size;
4443
4444                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4445                         u64 num_dec;
4446                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4447                         if (!del_item) {
4448                                 u64 orig_num_bytes =
4449                                         btrfs_file_extent_num_bytes(leaf, fi);
4450                                 extent_num_bytes = ALIGN(new_size -
4451                                                 found_key.offset,
4452                                                 root->sectorsize);
4453                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4454                                                          extent_num_bytes);
4455                                 num_dec = (orig_num_bytes -
4456                                            extent_num_bytes);
4457                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4458                                              &root->state) &&
4459                                     extent_start != 0)
4460                                         inode_sub_bytes(inode, num_dec);
4461                                 btrfs_mark_buffer_dirty(leaf);
4462                         } else {
4463                                 extent_num_bytes =
4464                                         btrfs_file_extent_disk_num_bytes(leaf,
4465                                                                          fi);
4466                                 extent_offset = found_key.offset -
4467                                         btrfs_file_extent_offset(leaf, fi);
4468
4469                                 /* FIXME blocksize != 4096 */
4470                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4471                                 if (extent_start != 0) {
4472                                         found_extent = 1;
4473                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4474                                                      &root->state))
4475                                                 inode_sub_bytes(inode, num_dec);
4476                                 }
4477                         }
4478                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4479                         /*
4480                          * we can't truncate inline items that have had
4481                          * special encodings
4482                          */
4483                         if (!del_item &&
4484                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4485                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4486
4487                                 /*
4488                                  * Need to release path in order to truncate a
4489                                  * compressed extent. So delete any accumulated
4490                                  * extent items so far.
4491                                  */
4492                                 if (btrfs_file_extent_compression(leaf, fi) !=
4493                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4494                                         err = btrfs_del_items(trans, root, path,
4495                                                               pending_del_slot,
4496                                                               pending_del_nr);
4497                                         if (err) {
4498                                                 btrfs_abort_transaction(trans,
4499                                                                         root,
4500                                                                         err);
4501                                                 goto error;
4502                                         }
4503                                         pending_del_nr = 0;
4504                                 }
4505
4506                                 err = truncate_inline_extent(inode, path,
4507                                                              &found_key,
4508                                                              item_end,
4509                                                              new_size);
4510                                 if (err) {
4511                                         btrfs_abort_transaction(trans,
4512                                                                 root, err);
4513                                         goto error;
4514                                 }
4515                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4516                                             &root->state)) {
4517                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4518                         }
4519                 }
4520 delete:
4521                 if (del_item) {
4522                         if (!pending_del_nr) {
4523                                 /* no pending yet, add ourselves */
4524                                 pending_del_slot = path->slots[0];
4525                                 pending_del_nr = 1;
4526                         } else if (pending_del_nr &&
4527                                    path->slots[0] + 1 == pending_del_slot) {
4528                                 /* hop on the pending chunk */
4529                                 pending_del_nr++;
4530                                 pending_del_slot = path->slots[0];
4531                         } else {
4532                                 BUG();
4533                         }
4534                 } else {
4535                         break;
4536                 }
4537                 should_throttle = 0;
4538
4539                 if (found_extent &&
4540                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4541                      root == root->fs_info->tree_root)) {
4542                         btrfs_set_path_blocking(path);
4543                         bytes_deleted += extent_num_bytes;
4544                         ret = btrfs_free_extent(trans, root, extent_start,
4545                                                 extent_num_bytes, 0,
4546                                                 btrfs_header_owner(leaf),
4547                                                 ino, extent_offset);
4548                         BUG_ON(ret);
4549                         if (btrfs_should_throttle_delayed_refs(trans, root))
4550                                 btrfs_async_run_delayed_refs(root,
4551                                         trans->delayed_ref_updates * 2, 0);
4552                         if (be_nice) {
4553                                 if (truncate_space_check(trans, root,
4554                                                          extent_num_bytes)) {
4555                                         should_end = 1;
4556                                 }
4557                                 if (btrfs_should_throttle_delayed_refs(trans,
4558                                                                        root)) {
4559                                         should_throttle = 1;
4560                                 }
4561                         }
4562                 }
4563
4564                 if (found_type == BTRFS_INODE_ITEM_KEY)
4565                         break;
4566
4567                 if (path->slots[0] == 0 ||
4568                     path->slots[0] != pending_del_slot ||
4569                     should_throttle || should_end) {
4570                         if (pending_del_nr) {
4571                                 ret = btrfs_del_items(trans, root, path,
4572                                                 pending_del_slot,
4573                                                 pending_del_nr);
4574                                 if (ret) {
4575                                         btrfs_abort_transaction(trans,
4576                                                                 root, ret);
4577                                         goto error;
4578                                 }
4579                                 pending_del_nr = 0;
4580                         }
4581                         btrfs_release_path(path);
4582                         if (should_throttle) {
4583                                 unsigned long updates = trans->delayed_ref_updates;
4584                                 if (updates) {
4585                                         trans->delayed_ref_updates = 0;
4586                                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4587                                         if (ret && !err)
4588                                                 err = ret;
4589                                 }
4590                         }
4591                         /*
4592                          * if we failed to refill our space rsv, bail out
4593                          * and let the transaction restart
4594                          */
4595                         if (should_end) {
4596                                 err = -EAGAIN;
4597                                 goto error;
4598                         }
4599                         goto search_again;
4600                 } else {
4601                         path->slots[0]--;
4602                 }
4603         }
4604 out:
4605         if (pending_del_nr) {
4606                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4607                                       pending_del_nr);
4608                 if (ret)
4609                         btrfs_abort_transaction(trans, root, ret);
4610         }
4611 error:
4612         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4613                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4614
4615         btrfs_free_path(path);
4616
4617         if (be_nice && bytes_deleted > SZ_32M) {
4618                 unsigned long updates = trans->delayed_ref_updates;
4619                 if (updates) {
4620                         trans->delayed_ref_updates = 0;
4621                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4622                         if (ret && !err)
4623                                 err = ret;
4624                 }
4625         }
4626         return err;
4627 }
4628
4629 /*
4630  * btrfs_truncate_block - read, zero a chunk and write a block
4631  * @inode - inode that we're zeroing
4632  * @from - the offset to start zeroing
4633  * @len - the length to zero, 0 to zero the entire range respective to the
4634  *      offset
4635  * @front - zero up to the offset instead of from the offset on
4636  *
4637  * This will find the block for the "from" offset and cow the block and zero the
4638  * part we want to zero.  This is used with truncate and hole punching.
4639  */
4640 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4641                         int front)
4642 {
4643         struct address_space *mapping = inode->i_mapping;
4644         struct btrfs_root *root = BTRFS_I(inode)->root;
4645         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4646         struct btrfs_ordered_extent *ordered;
4647         struct extent_state *cached_state = NULL;
4648         char *kaddr;
4649         u32 blocksize = root->sectorsize;
4650         pgoff_t index = from >> PAGE_SHIFT;
4651         unsigned offset = from & (blocksize - 1);
4652         struct page *page;
4653         gfp_t mask = btrfs_alloc_write_mask(mapping);
4654         int ret = 0;
4655         u64 block_start;
4656         u64 block_end;
4657
4658         if ((offset & (blocksize - 1)) == 0 &&
4659             (!len || ((len & (blocksize - 1)) == 0)))
4660                 goto out;
4661
4662         ret = btrfs_delalloc_reserve_space(inode,
4663                         round_down(from, blocksize), blocksize);
4664         if (ret)
4665                 goto out;
4666
4667 again:
4668         page = find_or_create_page(mapping, index, mask);
4669         if (!page) {
4670                 btrfs_delalloc_release_space(inode,
4671                                 round_down(from, blocksize),
4672                                 blocksize);
4673                 ret = -ENOMEM;
4674                 goto out;
4675         }
4676
4677         block_start = round_down(from, blocksize);
4678         block_end = block_start + blocksize - 1;
4679
4680         if (!PageUptodate(page)) {
4681                 ret = btrfs_readpage(NULL, page);
4682                 lock_page(page);
4683                 if (page->mapping != mapping) {
4684                         unlock_page(page);
4685                         put_page(page);
4686                         goto again;
4687                 }
4688                 if (!PageUptodate(page)) {
4689                         ret = -EIO;
4690                         goto out_unlock;
4691                 }
4692         }
4693         wait_on_page_writeback(page);
4694
4695         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4696         set_page_extent_mapped(page);
4697
4698         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4699         if (ordered) {
4700                 unlock_extent_cached(io_tree, block_start, block_end,
4701                                      &cached_state, GFP_NOFS);
4702                 unlock_page(page);
4703                 put_page(page);
4704                 btrfs_start_ordered_extent(inode, ordered, 1);
4705                 btrfs_put_ordered_extent(ordered);
4706                 goto again;
4707         }
4708
4709         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4710                           EXTENT_DIRTY | EXTENT_DELALLOC |
4711                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4712                           0, 0, &cached_state, GFP_NOFS);
4713
4714         ret = btrfs_set_extent_delalloc(inode, block_start, block_end,
4715                                         &cached_state);
4716         if (ret) {
4717                 unlock_extent_cached(io_tree, block_start, block_end,
4718                                      &cached_state, GFP_NOFS);
4719                 goto out_unlock;
4720         }
4721
4722         if (offset != blocksize) {
4723                 if (!len)
4724                         len = blocksize - offset;
4725                 kaddr = kmap(page);
4726                 if (front)
4727                         memset(kaddr + (block_start - page_offset(page)),
4728                                 0, offset);
4729                 else
4730                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4731                                 0, len);
4732                 flush_dcache_page(page);
4733                 kunmap(page);
4734         }
4735         ClearPageChecked(page);
4736         set_page_dirty(page);
4737         unlock_extent_cached(io_tree, block_start, block_end, &cached_state,
4738                              GFP_NOFS);
4739
4740 out_unlock:
4741         if (ret)
4742                 btrfs_delalloc_release_space(inode, block_start,
4743                                              blocksize);
4744         unlock_page(page);
4745         put_page(page);
4746 out:
4747         return ret;
4748 }
4749
4750 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4751                              u64 offset, u64 len)
4752 {
4753         struct btrfs_trans_handle *trans;
4754         int ret;
4755
4756         /*
4757          * Still need to make sure the inode looks like it's been updated so
4758          * that any holes get logged if we fsync.
4759          */
4760         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4761                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4762                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4763                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4764                 return 0;
4765         }
4766
4767         /*
4768          * 1 - for the one we're dropping
4769          * 1 - for the one we're adding
4770          * 1 - for updating the inode.
4771          */
4772         trans = btrfs_start_transaction(root, 3);
4773         if (IS_ERR(trans))
4774                 return PTR_ERR(trans);
4775
4776         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4777         if (ret) {
4778                 btrfs_abort_transaction(trans, root, ret);
4779                 btrfs_end_transaction(trans, root);
4780                 return ret;
4781         }
4782
4783         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4784                                        0, 0, len, 0, len, 0, 0, 0);
4785         if (ret)
4786                 btrfs_abort_transaction(trans, root, ret);
4787         else
4788                 btrfs_update_inode(trans, root, inode);
4789         btrfs_end_transaction(trans, root);
4790         return ret;
4791 }
4792
4793 /*
4794  * This function puts in dummy file extents for the area we're creating a hole
4795  * for.  So if we are truncating this file to a larger size we need to insert
4796  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4797  * the range between oldsize and size
4798  */
4799 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4800 {
4801         struct btrfs_root *root = BTRFS_I(inode)->root;
4802         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4803         struct extent_map *em = NULL;
4804         struct extent_state *cached_state = NULL;
4805         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4806         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4807         u64 block_end = ALIGN(size, root->sectorsize);
4808         u64 last_byte;
4809         u64 cur_offset;
4810         u64 hole_size;
4811         int err = 0;
4812
4813         /*
4814          * If our size started in the middle of a block we need to zero out the
4815          * rest of the block before we expand the i_size, otherwise we could
4816          * expose stale data.
4817          */
4818         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4819         if (err)
4820                 return err;
4821
4822         if (size <= hole_start)
4823                 return 0;
4824
4825         while (1) {
4826                 struct btrfs_ordered_extent *ordered;
4827
4828                 lock_extent_bits(io_tree, hole_start, block_end - 1,
4829                                  &cached_state);
4830                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4831                                                      block_end - hole_start);
4832                 if (!ordered)
4833                         break;
4834                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4835                                      &cached_state, GFP_NOFS);
4836                 btrfs_start_ordered_extent(inode, ordered, 1);
4837                 btrfs_put_ordered_extent(ordered);
4838         }
4839
4840         cur_offset = hole_start;
4841         while (1) {
4842                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4843                                 block_end - cur_offset, 0);
4844                 if (IS_ERR(em)) {
4845                         err = PTR_ERR(em);
4846                         em = NULL;
4847                         break;
4848                 }
4849                 last_byte = min(extent_map_end(em), block_end);
4850                 last_byte = ALIGN(last_byte , root->sectorsize);
4851                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4852                         struct extent_map *hole_em;
4853                         hole_size = last_byte - cur_offset;
4854
4855                         err = maybe_insert_hole(root, inode, cur_offset,
4856                                                 hole_size);
4857                         if (err)
4858                                 break;
4859                         btrfs_drop_extent_cache(inode, cur_offset,
4860                                                 cur_offset + hole_size - 1, 0);
4861                         hole_em = alloc_extent_map();
4862                         if (!hole_em) {
4863                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4864                                         &BTRFS_I(inode)->runtime_flags);
4865                                 goto next;
4866                         }
4867                         hole_em->start = cur_offset;
4868                         hole_em->len = hole_size;
4869                         hole_em->orig_start = cur_offset;
4870
4871                         hole_em->block_start = EXTENT_MAP_HOLE;
4872                         hole_em->block_len = 0;
4873                         hole_em->orig_block_len = 0;
4874                         hole_em->ram_bytes = hole_size;
4875                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4876                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4877                         hole_em->generation = root->fs_info->generation;
4878
4879                         while (1) {
4880                                 write_lock(&em_tree->lock);
4881                                 err = add_extent_mapping(em_tree, hole_em, 1);
4882                                 write_unlock(&em_tree->lock);
4883                                 if (err != -EEXIST)
4884                                         break;
4885                                 btrfs_drop_extent_cache(inode, cur_offset,
4886                                                         cur_offset +
4887                                                         hole_size - 1, 0);
4888                         }
4889                         free_extent_map(hole_em);
4890                 }
4891 next:
4892                 free_extent_map(em);
4893                 em = NULL;
4894                 cur_offset = last_byte;
4895                 if (cur_offset >= block_end)
4896                         break;
4897         }
4898         free_extent_map(em);
4899         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4900                              GFP_NOFS);
4901         return err;
4902 }
4903
4904 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4905 {
4906         struct btrfs_root *root = BTRFS_I(inode)->root;
4907         struct btrfs_trans_handle *trans;
4908         loff_t oldsize = i_size_read(inode);
4909         loff_t newsize = attr->ia_size;
4910         int mask = attr->ia_valid;
4911         int ret;
4912
4913         /*
4914          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4915          * special case where we need to update the times despite not having
4916          * these flags set.  For all other operations the VFS set these flags
4917          * explicitly if it wants a timestamp update.
4918          */
4919         if (newsize != oldsize) {
4920                 inode_inc_iversion(inode);
4921                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4922                         inode->i_ctime = inode->i_mtime =
4923                                 current_fs_time(inode->i_sb);
4924         }
4925
4926         if (newsize > oldsize) {
4927                 /*
4928                  * Don't do an expanding truncate while snapshoting is ongoing.
4929                  * This is to ensure the snapshot captures a fully consistent
4930                  * state of this file - if the snapshot captures this expanding
4931                  * truncation, it must capture all writes that happened before
4932                  * this truncation.
4933                  */
4934                 btrfs_wait_for_snapshot_creation(root);
4935                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4936                 if (ret) {
4937                         btrfs_end_write_no_snapshoting(root);
4938                         return ret;
4939                 }
4940
4941                 trans = btrfs_start_transaction(root, 1);
4942                 if (IS_ERR(trans)) {
4943                         btrfs_end_write_no_snapshoting(root);
4944                         return PTR_ERR(trans);
4945                 }
4946
4947                 i_size_write(inode, newsize);
4948                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4949                 pagecache_isize_extended(inode, oldsize, newsize);
4950                 ret = btrfs_update_inode(trans, root, inode);
4951                 btrfs_end_write_no_snapshoting(root);
4952                 btrfs_end_transaction(trans, root);
4953         } else {
4954
4955                 /*
4956                  * We're truncating a file that used to have good data down to
4957                  * zero. Make sure it gets into the ordered flush list so that
4958                  * any new writes get down to disk quickly.
4959                  */
4960                 if (newsize == 0)
4961                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4962                                 &BTRFS_I(inode)->runtime_flags);
4963
4964                 /*
4965                  * 1 for the orphan item we're going to add
4966                  * 1 for the orphan item deletion.
4967                  */
4968                 trans = btrfs_start_transaction(root, 2);
4969                 if (IS_ERR(trans))
4970                         return PTR_ERR(trans);
4971
4972                 /*
4973                  * We need to do this in case we fail at _any_ point during the
4974                  * actual truncate.  Once we do the truncate_setsize we could
4975                  * invalidate pages which forces any outstanding ordered io to
4976                  * be instantly completed which will give us extents that need
4977                  * to be truncated.  If we fail to get an orphan inode down we
4978                  * could have left over extents that were never meant to live,
4979                  * so we need to guarantee from this point on that everything
4980                  * will be consistent.
4981                  */
4982                 ret = btrfs_orphan_add(trans, inode);
4983                 btrfs_end_transaction(trans, root);
4984                 if (ret)
4985                         return ret;
4986
4987                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4988                 truncate_setsize(inode, newsize);
4989
4990                 /* Disable nonlocked read DIO to avoid the end less truncate */
4991                 btrfs_inode_block_unlocked_dio(inode);
4992                 inode_dio_wait(inode);
4993                 btrfs_inode_resume_unlocked_dio(inode);
4994
4995                 ret = btrfs_truncate(inode);
4996                 if (ret && inode->i_nlink) {
4997                         int err;
4998
4999                         /*
5000                          * failed to truncate, disk_i_size is only adjusted down
5001                          * as we remove extents, so it should represent the true
5002                          * size of the inode, so reset the in memory size and
5003                          * delete our orphan entry.
5004                          */
5005                         trans = btrfs_join_transaction(root);
5006                         if (IS_ERR(trans)) {
5007                                 btrfs_orphan_del(NULL, inode);
5008                                 return ret;
5009                         }
5010                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5011                         err = btrfs_orphan_del(trans, inode);
5012                         if (err)
5013                                 btrfs_abort_transaction(trans, root, err);
5014                         btrfs_end_transaction(trans, root);
5015                 }
5016         }
5017
5018         return ret;
5019 }
5020
5021 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5022 {
5023         struct inode *inode = d_inode(dentry);
5024         struct btrfs_root *root = BTRFS_I(inode)->root;
5025         int err;
5026
5027         if (btrfs_root_readonly(root))
5028                 return -EROFS;
5029
5030         err = inode_change_ok(inode, attr);
5031         if (err)
5032                 return err;
5033
5034         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5035                 err = btrfs_setsize(inode, attr);
5036                 if (err)
5037                         return err;
5038         }
5039
5040         if (attr->ia_valid) {
5041                 setattr_copy(inode, attr);
5042                 inode_inc_iversion(inode);
5043                 err = btrfs_dirty_inode(inode);
5044
5045                 if (!err && attr->ia_valid & ATTR_MODE)
5046                         err = posix_acl_chmod(inode, inode->i_mode);
5047         }
5048
5049         return err;
5050 }
5051
5052 /*
5053  * While truncating the inode pages during eviction, we get the VFS calling
5054  * btrfs_invalidatepage() against each page of the inode. This is slow because
5055  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5056  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5057  * extent_state structures over and over, wasting lots of time.
5058  *
5059  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5060  * those expensive operations on a per page basis and do only the ordered io
5061  * finishing, while we release here the extent_map and extent_state structures,
5062  * without the excessive merging and splitting.
5063  */
5064 static void evict_inode_truncate_pages(struct inode *inode)
5065 {
5066         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5067         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5068         struct rb_node *node;
5069
5070         ASSERT(inode->i_state & I_FREEING);
5071         truncate_inode_pages_final(&inode->i_data);
5072
5073         write_lock(&map_tree->lock);
5074         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5075                 struct extent_map *em;
5076
5077                 node = rb_first(&map_tree->map);
5078                 em = rb_entry(node, struct extent_map, rb_node);
5079                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5080                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5081                 remove_extent_mapping(map_tree, em);
5082                 free_extent_map(em);
5083                 if (need_resched()) {
5084                         write_unlock(&map_tree->lock);
5085                         cond_resched();
5086                         write_lock(&map_tree->lock);
5087                 }
5088         }
5089         write_unlock(&map_tree->lock);
5090
5091         /*
5092          * Keep looping until we have no more ranges in the io tree.
5093          * We can have ongoing bios started by readpages (called from readahead)
5094          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5095          * still in progress (unlocked the pages in the bio but did not yet
5096          * unlocked the ranges in the io tree). Therefore this means some
5097          * ranges can still be locked and eviction started because before
5098          * submitting those bios, which are executed by a separate task (work
5099          * queue kthread), inode references (inode->i_count) were not taken
5100          * (which would be dropped in the end io callback of each bio).
5101          * Therefore here we effectively end up waiting for those bios and
5102          * anyone else holding locked ranges without having bumped the inode's
5103          * reference count - if we don't do it, when they access the inode's
5104          * io_tree to unlock a range it may be too late, leading to an
5105          * use-after-free issue.
5106          */
5107         spin_lock(&io_tree->lock);
5108         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5109                 struct extent_state *state;
5110                 struct extent_state *cached_state = NULL;
5111                 u64 start;
5112                 u64 end;
5113
5114                 node = rb_first(&io_tree->state);
5115                 state = rb_entry(node, struct extent_state, rb_node);
5116                 start = state->start;
5117                 end = state->end;
5118                 spin_unlock(&io_tree->lock);
5119
5120                 lock_extent_bits(io_tree, start, end, &cached_state);
5121
5122                 /*
5123                  * If still has DELALLOC flag, the extent didn't reach disk,
5124                  * and its reserved space won't be freed by delayed_ref.
5125                  * So we need to free its reserved space here.
5126                  * (Refer to comment in btrfs_invalidatepage, case 2)
5127                  *
5128                  * Note, end is the bytenr of last byte, so we need + 1 here.
5129                  */
5130                 if (state->state & EXTENT_DELALLOC)
5131                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5132
5133                 clear_extent_bit(io_tree, start, end,
5134                                  EXTENT_LOCKED | EXTENT_DIRTY |
5135                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5136                                  EXTENT_DEFRAG, 1, 1,
5137                                  &cached_state, GFP_NOFS);
5138
5139                 cond_resched();
5140                 spin_lock(&io_tree->lock);
5141         }
5142         spin_unlock(&io_tree->lock);
5143 }
5144
5145 void btrfs_evict_inode(struct inode *inode)
5146 {
5147         struct btrfs_trans_handle *trans;
5148         struct btrfs_root *root = BTRFS_I(inode)->root;
5149         struct btrfs_block_rsv *rsv, *global_rsv;
5150         int steal_from_global = 0;
5151         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
5152         int ret;
5153
5154         trace_btrfs_inode_evict(inode);
5155
5156         evict_inode_truncate_pages(inode);
5157
5158         if (inode->i_nlink &&
5159             ((btrfs_root_refs(&root->root_item) != 0 &&
5160               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5161              btrfs_is_free_space_inode(inode)))
5162                 goto no_delete;
5163
5164         if (is_bad_inode(inode)) {
5165                 btrfs_orphan_del(NULL, inode);
5166                 goto no_delete;
5167         }
5168         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5169         if (!special_file(inode->i_mode))
5170                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5171
5172         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5173
5174         if (root->fs_info->log_root_recovering) {
5175                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5176                                  &BTRFS_I(inode)->runtime_flags));
5177                 goto no_delete;
5178         }
5179
5180         if (inode->i_nlink > 0) {
5181                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5182                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5183                 goto no_delete;
5184         }
5185
5186         ret = btrfs_commit_inode_delayed_inode(inode);
5187         if (ret) {
5188                 btrfs_orphan_del(NULL, inode);
5189                 goto no_delete;
5190         }
5191
5192         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
5193         if (!rsv) {
5194                 btrfs_orphan_del(NULL, inode);
5195                 goto no_delete;
5196         }
5197         rsv->size = min_size;
5198         rsv->failfast = 1;
5199         global_rsv = &root->fs_info->global_block_rsv;
5200
5201         btrfs_i_size_write(inode, 0);
5202
5203         /*
5204          * This is a bit simpler than btrfs_truncate since we've already
5205          * reserved our space for our orphan item in the unlink, so we just
5206          * need to reserve some slack space in case we add bytes and update
5207          * inode item when doing the truncate.
5208          */
5209         while (1) {
5210                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5211                                              BTRFS_RESERVE_FLUSH_LIMIT);
5212
5213                 /*
5214                  * Try and steal from the global reserve since we will
5215                  * likely not use this space anyway, we want to try as
5216                  * hard as possible to get this to work.
5217                  */
5218                 if (ret)
5219                         steal_from_global++;
5220                 else
5221                         steal_from_global = 0;
5222                 ret = 0;
5223
5224                 /*
5225                  * steal_from_global == 0: we reserved stuff, hooray!
5226                  * steal_from_global == 1: we didn't reserve stuff, boo!
5227                  * steal_from_global == 2: we've committed, still not a lot of
5228                  * room but maybe we'll have room in the global reserve this
5229                  * time.
5230                  * steal_from_global == 3: abandon all hope!
5231                  */
5232                 if (steal_from_global > 2) {
5233                         btrfs_warn(root->fs_info,
5234                                 "Could not get space for a delete, will truncate on mount %d",
5235                                 ret);
5236                         btrfs_orphan_del(NULL, inode);
5237                         btrfs_free_block_rsv(root, rsv);
5238                         goto no_delete;
5239                 }
5240
5241                 trans = btrfs_join_transaction(root);
5242                 if (IS_ERR(trans)) {
5243                         btrfs_orphan_del(NULL, inode);
5244                         btrfs_free_block_rsv(root, rsv);
5245                         goto no_delete;
5246                 }
5247
5248                 /*
5249                  * We can't just steal from the global reserve, we need to make
5250                  * sure there is room to do it, if not we need to commit and try
5251                  * again.
5252                  */
5253                 if (steal_from_global) {
5254                         if (!btrfs_check_space_for_delayed_refs(trans, root))
5255                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5256                                                               min_size);
5257                         else
5258                                 ret = -ENOSPC;
5259                 }
5260
5261                 /*
5262                  * Couldn't steal from the global reserve, we have too much
5263                  * pending stuff built up, commit the transaction and try it
5264                  * again.
5265                  */
5266                 if (ret) {
5267                         ret = btrfs_commit_transaction(trans, root);
5268                         if (ret) {
5269                                 btrfs_orphan_del(NULL, inode);
5270                                 btrfs_free_block_rsv(root, rsv);
5271                                 goto no_delete;
5272                         }
5273                         continue;
5274                 } else {
5275                         steal_from_global = 0;
5276                 }
5277
5278                 trans->block_rsv = rsv;
5279
5280                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5281                 if (ret != -ENOSPC && ret != -EAGAIN)
5282                         break;
5283
5284                 trans->block_rsv = &root->fs_info->trans_block_rsv;
5285                 btrfs_end_transaction(trans, root);
5286                 trans = NULL;
5287                 btrfs_btree_balance_dirty(root);
5288         }
5289
5290         btrfs_free_block_rsv(root, rsv);
5291
5292         /*
5293          * Errors here aren't a big deal, it just means we leave orphan items
5294          * in the tree.  They will be cleaned up on the next mount.
5295          */
5296         if (ret == 0) {
5297                 trans->block_rsv = root->orphan_block_rsv;
5298                 btrfs_orphan_del(trans, inode);
5299         } else {
5300                 btrfs_orphan_del(NULL, inode);
5301         }
5302
5303         trans->block_rsv = &root->fs_info->trans_block_rsv;
5304         if (!(root == root->fs_info->tree_root ||
5305               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5306                 btrfs_return_ino(root, btrfs_ino(inode));
5307
5308         btrfs_end_transaction(trans, root);
5309         btrfs_btree_balance_dirty(root);
5310 no_delete:
5311         btrfs_remove_delayed_node(inode);
5312         clear_inode(inode);
5313 }
5314
5315 /*
5316  * this returns the key found in the dir entry in the location pointer.
5317  * If no dir entries were found, location->objectid is 0.
5318  */
5319 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5320                                struct btrfs_key *location)
5321 {
5322         const char *name = dentry->d_name.name;
5323         int namelen = dentry->d_name.len;
5324         struct btrfs_dir_item *di;
5325         struct btrfs_path *path;
5326         struct btrfs_root *root = BTRFS_I(dir)->root;
5327         int ret = 0;
5328
5329         path = btrfs_alloc_path();
5330         if (!path)
5331                 return -ENOMEM;
5332
5333         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
5334                                     namelen, 0);
5335         if (IS_ERR(di))
5336                 ret = PTR_ERR(di);
5337
5338         if (IS_ERR_OR_NULL(di))
5339                 goto out_err;
5340
5341         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5342 out:
5343         btrfs_free_path(path);
5344         return ret;
5345 out_err:
5346         location->objectid = 0;
5347         goto out;
5348 }
5349
5350 /*
5351  * when we hit a tree root in a directory, the btrfs part of the inode
5352  * needs to be changed to reflect the root directory of the tree root.  This
5353  * is kind of like crossing a mount point.
5354  */
5355 static int fixup_tree_root_location(struct btrfs_root *root,
5356                                     struct inode *dir,
5357                                     struct dentry *dentry,
5358                                     struct btrfs_key *location,
5359                                     struct btrfs_root **sub_root)
5360 {
5361         struct btrfs_path *path;
5362         struct btrfs_root *new_root;
5363         struct btrfs_root_ref *ref;
5364         struct extent_buffer *leaf;
5365         struct btrfs_key key;
5366         int ret;
5367         int err = 0;
5368
5369         path = btrfs_alloc_path();
5370         if (!path) {
5371                 err = -ENOMEM;
5372                 goto out;
5373         }
5374
5375         err = -ENOENT;
5376         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5377         key.type = BTRFS_ROOT_REF_KEY;
5378         key.offset = location->objectid;
5379
5380         ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, path,
5381                                 0, 0);
5382         if (ret) {
5383                 if (ret < 0)
5384                         err = ret;
5385                 goto out;
5386         }
5387
5388         leaf = path->nodes[0];
5389         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5390         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5391             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5392                 goto out;
5393
5394         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5395                                    (unsigned long)(ref + 1),
5396                                    dentry->d_name.len);
5397         if (ret)
5398                 goto out;
5399
5400         btrfs_release_path(path);
5401
5402         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5403         if (IS_ERR(new_root)) {
5404                 err = PTR_ERR(new_root);
5405                 goto out;
5406         }
5407
5408         *sub_root = new_root;
5409         location->objectid = btrfs_root_dirid(&new_root->root_item);
5410         location->type = BTRFS_INODE_ITEM_KEY;
5411         location->offset = 0;
5412         err = 0;
5413 out:
5414         btrfs_free_path(path);
5415         return err;
5416 }
5417
5418 static void inode_tree_add(struct inode *inode)
5419 {
5420         struct btrfs_root *root = BTRFS_I(inode)->root;
5421         struct btrfs_inode *entry;
5422         struct rb_node **p;
5423         struct rb_node *parent;
5424         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5425         u64 ino = btrfs_ino(inode);
5426
5427         if (inode_unhashed(inode))
5428                 return;
5429         parent = NULL;
5430         spin_lock(&root->inode_lock);
5431         p = &root->inode_tree.rb_node;
5432         while (*p) {
5433                 parent = *p;
5434                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5435
5436                 if (ino < btrfs_ino(&entry->vfs_inode))
5437                         p = &parent->rb_left;
5438                 else if (ino > btrfs_ino(&entry->vfs_inode))
5439                         p = &parent->rb_right;
5440                 else {
5441                         WARN_ON(!(entry->vfs_inode.i_state &
5442                                   (I_WILL_FREE | I_FREEING)));
5443                         rb_replace_node(parent, new, &root->inode_tree);
5444                         RB_CLEAR_NODE(parent);
5445                         spin_unlock(&root->inode_lock);
5446                         return;
5447                 }
5448         }
5449         rb_link_node(new, parent, p);
5450         rb_insert_color(new, &root->inode_tree);
5451         spin_unlock(&root->inode_lock);
5452 }
5453
5454 static void inode_tree_del(struct inode *inode)
5455 {
5456         struct btrfs_root *root = BTRFS_I(inode)->root;
5457         int empty = 0;
5458
5459         spin_lock(&root->inode_lock);
5460         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5461                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5462                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5463                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5464         }
5465         spin_unlock(&root->inode_lock);
5466
5467         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5468                 synchronize_srcu(&root->fs_info->subvol_srcu);
5469                 spin_lock(&root->inode_lock);
5470                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5471                 spin_unlock(&root->inode_lock);
5472                 if (empty)
5473                         btrfs_add_dead_root(root);
5474         }
5475 }
5476
5477 void btrfs_invalidate_inodes(struct btrfs_root *root)
5478 {
5479         struct rb_node *node;
5480         struct rb_node *prev;
5481         struct btrfs_inode *entry;
5482         struct inode *inode;
5483         u64 objectid = 0;
5484
5485         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5486                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5487
5488         spin_lock(&root->inode_lock);
5489 again:
5490         node = root->inode_tree.rb_node;
5491         prev = NULL;
5492         while (node) {
5493                 prev = node;
5494                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5495
5496                 if (objectid < btrfs_ino(&entry->vfs_inode))
5497                         node = node->rb_left;
5498                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5499                         node = node->rb_right;
5500                 else
5501                         break;
5502         }
5503         if (!node) {
5504                 while (prev) {
5505                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5506                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5507                                 node = prev;
5508                                 break;
5509                         }
5510                         prev = rb_next(prev);
5511                 }
5512         }
5513         while (node) {
5514                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5515                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5516                 inode = igrab(&entry->vfs_inode);
5517                 if (inode) {
5518                         spin_unlock(&root->inode_lock);
5519                         if (atomic_read(&inode->i_count) > 1)
5520                                 d_prune_aliases(inode);
5521                         /*
5522                          * btrfs_drop_inode will have it removed from
5523                          * the inode cache when its usage count
5524                          * hits zero.
5525                          */
5526                         iput(inode);
5527                         cond_resched();
5528                         spin_lock(&root->inode_lock);
5529                         goto again;
5530                 }
5531
5532                 if (cond_resched_lock(&root->inode_lock))
5533                         goto again;
5534
5535                 node = rb_next(node);
5536         }
5537         spin_unlock(&root->inode_lock);
5538 }
5539
5540 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5541 {
5542         struct btrfs_iget_args *args = p;
5543         inode->i_ino = args->location->objectid;
5544         memcpy(&BTRFS_I(inode)->location, args->location,
5545                sizeof(*args->location));
5546         BTRFS_I(inode)->root = args->root;
5547         return 0;
5548 }
5549
5550 static int btrfs_find_actor(struct inode *inode, void *opaque)
5551 {
5552         struct btrfs_iget_args *args = opaque;
5553         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5554                 args->root == BTRFS_I(inode)->root;
5555 }
5556
5557 static struct inode *btrfs_iget_locked(struct super_block *s,
5558                                        struct btrfs_key *location,
5559                                        struct btrfs_root *root)
5560 {
5561         struct inode *inode;
5562         struct btrfs_iget_args args;
5563         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5564
5565         args.location = location;
5566         args.root = root;
5567
5568         inode = iget5_locked(s, hashval, btrfs_find_actor,
5569                              btrfs_init_locked_inode,
5570                              (void *)&args);
5571         return inode;
5572 }
5573
5574 /* Get an inode object given its location and corresponding root.
5575  * Returns in *is_new if the inode was read from disk
5576  */
5577 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5578                          struct btrfs_root *root, int *new)
5579 {
5580         struct inode *inode;
5581
5582         inode = btrfs_iget_locked(s, location, root);
5583         if (!inode)
5584                 return ERR_PTR(-ENOMEM);
5585
5586         if (inode->i_state & I_NEW) {
5587                 btrfs_read_locked_inode(inode);
5588                 if (!is_bad_inode(inode)) {
5589                         inode_tree_add(inode);
5590                         unlock_new_inode(inode);
5591                         if (new)
5592                                 *new = 1;
5593                 } else {
5594                         unlock_new_inode(inode);
5595                         iput(inode);
5596                         inode = ERR_PTR(-ESTALE);
5597                 }
5598         }
5599
5600         return inode;
5601 }
5602
5603 static struct inode *new_simple_dir(struct super_block *s,
5604                                     struct btrfs_key *key,
5605                                     struct btrfs_root *root)
5606 {
5607         struct inode *inode = new_inode(s);
5608
5609         if (!inode)
5610                 return ERR_PTR(-ENOMEM);
5611
5612         BTRFS_I(inode)->root = root;
5613         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5614         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5615
5616         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5617         inode->i_op = &btrfs_dir_ro_inode_operations;
5618         inode->i_fop = &simple_dir_operations;
5619         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5620         inode->i_mtime = current_fs_time(inode->i_sb);
5621         inode->i_atime = inode->i_mtime;
5622         inode->i_ctime = inode->i_mtime;
5623         BTRFS_I(inode)->i_otime = inode->i_mtime;
5624
5625         return inode;
5626 }
5627
5628 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5629 {
5630         struct inode *inode;
5631         struct btrfs_root *root = BTRFS_I(dir)->root;
5632         struct btrfs_root *sub_root = root;
5633         struct btrfs_key location;
5634         int index;
5635         int ret = 0;
5636
5637         if (dentry->d_name.len > BTRFS_NAME_LEN)
5638                 return ERR_PTR(-ENAMETOOLONG);
5639
5640         ret = btrfs_inode_by_name(dir, dentry, &location);
5641         if (ret < 0)
5642                 return ERR_PTR(ret);
5643
5644         if (location.objectid == 0)
5645                 return ERR_PTR(-ENOENT);
5646
5647         if (location.type == BTRFS_INODE_ITEM_KEY) {
5648                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5649                 return inode;
5650         }
5651
5652         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5653
5654         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5655         ret = fixup_tree_root_location(root, dir, dentry,
5656                                        &location, &sub_root);
5657         if (ret < 0) {
5658                 if (ret != -ENOENT)
5659                         inode = ERR_PTR(ret);
5660                 else
5661                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5662         } else {
5663                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5664         }
5665         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5666
5667         if (!IS_ERR(inode) && root != sub_root) {
5668                 down_read(&root->fs_info->cleanup_work_sem);
5669                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5670                         ret = btrfs_orphan_cleanup(sub_root);
5671                 up_read(&root->fs_info->cleanup_work_sem);
5672                 if (ret) {
5673                         iput(inode);
5674                         inode = ERR_PTR(ret);
5675                 }
5676         }
5677
5678         return inode;
5679 }
5680
5681 static int btrfs_dentry_delete(const struct dentry *dentry)
5682 {
5683         struct btrfs_root *root;
5684         struct inode *inode = d_inode(dentry);
5685
5686         if (!inode && !IS_ROOT(dentry))
5687                 inode = d_inode(dentry->d_parent);
5688
5689         if (inode) {
5690                 root = BTRFS_I(inode)->root;
5691                 if (btrfs_root_refs(&root->root_item) == 0)
5692                         return 1;
5693
5694                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5695                         return 1;
5696         }
5697         return 0;
5698 }
5699
5700 static void btrfs_dentry_release(struct dentry *dentry)
5701 {
5702         kfree(dentry->d_fsdata);
5703 }
5704
5705 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5706                                    unsigned int flags)
5707 {
5708         struct inode *inode;
5709
5710         inode = btrfs_lookup_dentry(dir, dentry);
5711         if (IS_ERR(inode)) {
5712                 if (PTR_ERR(inode) == -ENOENT)
5713                         inode = NULL;
5714                 else
5715                         return ERR_CAST(inode);
5716         }
5717
5718         return d_splice_alias(inode, dentry);
5719 }
5720
5721 unsigned char btrfs_filetype_table[] = {
5722         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5723 };
5724
5725 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5726 {
5727         struct inode *inode = file_inode(file);
5728         struct btrfs_root *root = BTRFS_I(inode)->root;
5729         struct btrfs_item *item;
5730         struct btrfs_dir_item *di;
5731         struct btrfs_key key;
5732         struct btrfs_key found_key;
5733         struct btrfs_path *path;
5734         struct list_head ins_list;
5735         struct list_head del_list;
5736         int ret;
5737         struct extent_buffer *leaf;
5738         int slot;
5739         unsigned char d_type;
5740         int over = 0;
5741         u32 di_cur;
5742         u32 di_total;
5743         u32 di_len;
5744         int key_type = BTRFS_DIR_INDEX_KEY;
5745         char tmp_name[32];
5746         char *name_ptr;
5747         int name_len;
5748         int is_curr = 0;        /* ctx->pos points to the current index? */
5749         bool emitted;
5750
5751         /* FIXME, use a real flag for deciding about the key type */
5752         if (root->fs_info->tree_root == root)
5753                 key_type = BTRFS_DIR_ITEM_KEY;
5754
5755         if (!dir_emit_dots(file, ctx))
5756                 return 0;
5757
5758         path = btrfs_alloc_path();
5759         if (!path)
5760                 return -ENOMEM;
5761
5762         path->reada = READA_FORWARD;
5763
5764         if (key_type == BTRFS_DIR_INDEX_KEY) {
5765                 INIT_LIST_HEAD(&ins_list);
5766                 INIT_LIST_HEAD(&del_list);
5767                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5768         }
5769
5770         key.type = key_type;
5771         key.offset = ctx->pos;
5772         key.objectid = btrfs_ino(inode);
5773
5774         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5775         if (ret < 0)
5776                 goto err;
5777
5778         emitted = false;
5779         while (1) {
5780                 leaf = path->nodes[0];
5781                 slot = path->slots[0];
5782                 if (slot >= btrfs_header_nritems(leaf)) {
5783                         ret = btrfs_next_leaf(root, path);
5784                         if (ret < 0)
5785                                 goto err;
5786                         else if (ret > 0)
5787                                 break;
5788                         continue;
5789                 }
5790
5791                 item = btrfs_item_nr(slot);
5792                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5793
5794                 if (found_key.objectid != key.objectid)
5795                         break;
5796                 if (found_key.type != key_type)
5797                         break;
5798                 if (found_key.offset < ctx->pos)
5799                         goto next;
5800                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5801                     btrfs_should_delete_dir_index(&del_list,
5802                                                   found_key.offset))
5803                         goto next;
5804
5805                 ctx->pos = found_key.offset;
5806                 is_curr = 1;
5807
5808                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5809                 di_cur = 0;
5810                 di_total = btrfs_item_size(leaf, item);
5811
5812                 while (di_cur < di_total) {
5813                         struct btrfs_key location;
5814
5815                         if (verify_dir_item(root, leaf, di))
5816                                 break;
5817
5818                         name_len = btrfs_dir_name_len(leaf, di);
5819                         if (name_len <= sizeof(tmp_name)) {
5820                                 name_ptr = tmp_name;
5821                         } else {
5822                                 name_ptr = kmalloc(name_len, GFP_KERNEL);
5823                                 if (!name_ptr) {
5824                                         ret = -ENOMEM;
5825                                         goto err;
5826                                 }
5827                         }
5828                         read_extent_buffer(leaf, name_ptr,
5829                                            (unsigned long)(di + 1), name_len);
5830
5831                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5832                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5833
5834
5835                         /* is this a reference to our own snapshot? If so
5836                          * skip it.
5837                          *
5838                          * In contrast to old kernels, we insert the snapshot's
5839                          * dir item and dir index after it has been created, so
5840                          * we won't find a reference to our own snapshot. We
5841                          * still keep the following code for backward
5842                          * compatibility.
5843                          */
5844                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5845                             location.objectid == root->root_key.objectid) {
5846                                 over = 0;
5847                                 goto skip;
5848                         }
5849                         over = !dir_emit(ctx, name_ptr, name_len,
5850                                        location.objectid, d_type);
5851
5852 skip:
5853                         if (name_ptr != tmp_name)
5854                                 kfree(name_ptr);
5855
5856                         if (over)
5857                                 goto nopos;
5858                         emitted = true;
5859                         di_len = btrfs_dir_name_len(leaf, di) +
5860                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5861                         di_cur += di_len;
5862                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5863                 }
5864 next:
5865                 path->slots[0]++;
5866         }
5867
5868         if (key_type == BTRFS_DIR_INDEX_KEY) {
5869                 if (is_curr)
5870                         ctx->pos++;
5871                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list, &emitted);
5872                 if (ret)
5873                         goto nopos;
5874         }
5875
5876         /*
5877          * If we haven't emitted any dir entry, we must not touch ctx->pos as
5878          * it was was set to the termination value in previous call. We assume
5879          * that "." and ".." were emitted if we reach this point and set the
5880          * termination value as well for an empty directory.
5881          */
5882         if (ctx->pos > 2 && !emitted)
5883                 goto nopos;
5884
5885         /* Reached end of directory/root. Bump pos past the last item. */
5886         ctx->pos++;
5887
5888         /*
5889          * Stop new entries from being returned after we return the last
5890          * entry.
5891          *
5892          * New directory entries are assigned a strictly increasing
5893          * offset.  This means that new entries created during readdir
5894          * are *guaranteed* to be seen in the future by that readdir.
5895          * This has broken buggy programs which operate on names as
5896          * they're returned by readdir.  Until we re-use freed offsets
5897          * we have this hack to stop new entries from being returned
5898          * under the assumption that they'll never reach this huge
5899          * offset.
5900          *
5901          * This is being careful not to overflow 32bit loff_t unless the
5902          * last entry requires it because doing so has broken 32bit apps
5903          * in the past.
5904          */
5905         if (key_type == BTRFS_DIR_INDEX_KEY) {
5906                 if (ctx->pos >= INT_MAX)
5907                         ctx->pos = LLONG_MAX;
5908                 else
5909                         ctx->pos = INT_MAX;
5910         }
5911 nopos:
5912         ret = 0;
5913 err:
5914         if (key_type == BTRFS_DIR_INDEX_KEY)
5915                 btrfs_put_delayed_items(&ins_list, &del_list);
5916         btrfs_free_path(path);
5917         return ret;
5918 }
5919
5920 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5921 {
5922         struct btrfs_root *root = BTRFS_I(inode)->root;
5923         struct btrfs_trans_handle *trans;
5924         int ret = 0;
5925         bool nolock = false;
5926
5927         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5928                 return 0;
5929
5930         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5931                 nolock = true;
5932
5933         if (wbc->sync_mode == WB_SYNC_ALL) {
5934                 if (nolock)
5935                         trans = btrfs_join_transaction_nolock(root);
5936                 else
5937                         trans = btrfs_join_transaction(root);
5938                 if (IS_ERR(trans))
5939                         return PTR_ERR(trans);
5940                 ret = btrfs_commit_transaction(trans, root);
5941         }
5942         return ret;
5943 }
5944
5945 /*
5946  * This is somewhat expensive, updating the tree every time the
5947  * inode changes.  But, it is most likely to find the inode in cache.
5948  * FIXME, needs more benchmarking...there are no reasons other than performance
5949  * to keep or drop this code.
5950  */
5951 static int btrfs_dirty_inode(struct inode *inode)
5952 {
5953         struct btrfs_root *root = BTRFS_I(inode)->root;
5954         struct btrfs_trans_handle *trans;
5955         int ret;
5956
5957         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5958                 return 0;
5959
5960         trans = btrfs_join_transaction(root);
5961         if (IS_ERR(trans))
5962                 return PTR_ERR(trans);
5963
5964         ret = btrfs_update_inode(trans, root, inode);
5965         if (ret && ret == -ENOSPC) {
5966                 /* whoops, lets try again with the full transaction */
5967                 btrfs_end_transaction(trans, root);
5968                 trans = btrfs_start_transaction(root, 1);
5969                 if (IS_ERR(trans))
5970                         return PTR_ERR(trans);
5971
5972                 ret = btrfs_update_inode(trans, root, inode);
5973         }
5974         btrfs_end_transaction(trans, root);
5975         if (BTRFS_I(inode)->delayed_node)
5976                 btrfs_balance_delayed_items(root);
5977
5978         return ret;
5979 }
5980
5981 /*
5982  * This is a copy of file_update_time.  We need this so we can return error on
5983  * ENOSPC for updating the inode in the case of file write and mmap writes.
5984  */
5985 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5986                              int flags)
5987 {
5988         struct btrfs_root *root = BTRFS_I(inode)->root;
5989
5990         if (btrfs_root_readonly(root))
5991                 return -EROFS;
5992
5993         if (flags & S_VERSION)
5994                 inode_inc_iversion(inode);
5995         if (flags & S_CTIME)
5996                 inode->i_ctime = *now;
5997         if (flags & S_MTIME)
5998                 inode->i_mtime = *now;
5999         if (flags & S_ATIME)
6000                 inode->i_atime = *now;
6001         return btrfs_dirty_inode(inode);
6002 }
6003
6004 /*
6005  * find the highest existing sequence number in a directory
6006  * and then set the in-memory index_cnt variable to reflect
6007  * free sequence numbers
6008  */
6009 static int btrfs_set_inode_index_count(struct inode *inode)
6010 {
6011         struct btrfs_root *root = BTRFS_I(inode)->root;
6012         struct btrfs_key key, found_key;
6013         struct btrfs_path *path;
6014         struct extent_buffer *leaf;
6015         int ret;
6016
6017         key.objectid = btrfs_ino(inode);
6018         key.type = BTRFS_DIR_INDEX_KEY;
6019         key.offset = (u64)-1;
6020
6021         path = btrfs_alloc_path();
6022         if (!path)
6023                 return -ENOMEM;
6024
6025         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6026         if (ret < 0)
6027                 goto out;
6028         /* FIXME: we should be able to handle this */
6029         if (ret == 0)
6030                 goto out;
6031         ret = 0;
6032
6033         /*
6034          * MAGIC NUMBER EXPLANATION:
6035          * since we search a directory based on f_pos we have to start at 2
6036          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6037          * else has to start at 2
6038          */
6039         if (path->slots[0] == 0) {
6040                 BTRFS_I(inode)->index_cnt = 2;
6041                 goto out;
6042         }
6043
6044         path->slots[0]--;
6045
6046         leaf = path->nodes[0];
6047         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6048
6049         if (found_key.objectid != btrfs_ino(inode) ||
6050             found_key.type != BTRFS_DIR_INDEX_KEY) {
6051                 BTRFS_I(inode)->index_cnt = 2;
6052                 goto out;
6053         }
6054
6055         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6056 out:
6057         btrfs_free_path(path);
6058         return ret;
6059 }
6060
6061 /*
6062  * helper to find a free sequence number in a given directory.  This current
6063  * code is very simple, later versions will do smarter things in the btree
6064  */
6065 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6066 {
6067         int ret = 0;
6068
6069         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6070                 ret = btrfs_inode_delayed_dir_index_count(dir);
6071                 if (ret) {
6072                         ret = btrfs_set_inode_index_count(dir);
6073                         if (ret)
6074                                 return ret;
6075                 }
6076         }
6077
6078         *index = BTRFS_I(dir)->index_cnt;
6079         BTRFS_I(dir)->index_cnt++;
6080
6081         return ret;
6082 }
6083
6084 static int btrfs_insert_inode_locked(struct inode *inode)
6085 {
6086         struct btrfs_iget_args args;
6087         args.location = &BTRFS_I(inode)->location;
6088         args.root = BTRFS_I(inode)->root;
6089
6090         return insert_inode_locked4(inode,
6091                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6092                    btrfs_find_actor, &args);
6093 }
6094
6095 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6096                                      struct btrfs_root *root,
6097                                      struct inode *dir,
6098                                      const char *name, int name_len,
6099                                      u64 ref_objectid, u64 objectid,
6100                                      umode_t mode, u64 *index)
6101 {
6102         struct inode *inode;
6103         struct btrfs_inode_item *inode_item;
6104         struct btrfs_key *location;
6105         struct btrfs_path *path;
6106         struct btrfs_inode_ref *ref;
6107         struct btrfs_key key[2];
6108         u32 sizes[2];
6109         int nitems = name ? 2 : 1;
6110         unsigned long ptr;
6111         int ret;
6112
6113         path = btrfs_alloc_path();
6114         if (!path)
6115                 return ERR_PTR(-ENOMEM);
6116
6117         inode = new_inode(root->fs_info->sb);
6118         if (!inode) {
6119                 btrfs_free_path(path);
6120                 return ERR_PTR(-ENOMEM);
6121         }
6122
6123         /*
6124          * O_TMPFILE, set link count to 0, so that after this point,
6125          * we fill in an inode item with the correct link count.
6126          */
6127         if (!name)
6128                 set_nlink(inode, 0);
6129
6130         /*
6131          * we have to initialize this early, so we can reclaim the inode
6132          * number if we fail afterwards in this function.
6133          */
6134         inode->i_ino = objectid;
6135
6136         if (dir && name) {
6137                 trace_btrfs_inode_request(dir);
6138
6139                 ret = btrfs_set_inode_index(dir, index);
6140                 if (ret) {
6141                         btrfs_free_path(path);
6142                         iput(inode);
6143                         return ERR_PTR(ret);
6144                 }
6145         } else if (dir) {
6146                 *index = 0;
6147         }
6148         /*
6149          * index_cnt is ignored for everything but a dir,
6150          * btrfs_get_inode_index_count has an explanation for the magic
6151          * number
6152          */
6153         BTRFS_I(inode)->index_cnt = 2;
6154         BTRFS_I(inode)->dir_index = *index;
6155         BTRFS_I(inode)->root = root;
6156         BTRFS_I(inode)->generation = trans->transid;
6157         inode->i_generation = BTRFS_I(inode)->generation;
6158
6159         /*
6160          * We could have gotten an inode number from somebody who was fsynced
6161          * and then removed in this same transaction, so let's just set full
6162          * sync since it will be a full sync anyway and this will blow away the
6163          * old info in the log.
6164          */
6165         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6166
6167         key[0].objectid = objectid;
6168         key[0].type = BTRFS_INODE_ITEM_KEY;
6169         key[0].offset = 0;
6170
6171         sizes[0] = sizeof(struct btrfs_inode_item);
6172
6173         if (name) {
6174                 /*
6175                  * Start new inodes with an inode_ref. This is slightly more
6176                  * efficient for small numbers of hard links since they will
6177                  * be packed into one item. Extended refs will kick in if we
6178                  * add more hard links than can fit in the ref item.
6179                  */
6180                 key[1].objectid = objectid;
6181                 key[1].type = BTRFS_INODE_REF_KEY;
6182                 key[1].offset = ref_objectid;
6183
6184                 sizes[1] = name_len + sizeof(*ref);
6185         }
6186
6187         location = &BTRFS_I(inode)->location;
6188         location->objectid = objectid;
6189         location->offset = 0;
6190         location->type = BTRFS_INODE_ITEM_KEY;
6191
6192         ret = btrfs_insert_inode_locked(inode);
6193         if (ret < 0)
6194                 goto fail;
6195
6196         path->leave_spinning = 1;
6197         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6198         if (ret != 0)
6199                 goto fail_unlock;
6200
6201         inode_init_owner(inode, dir, mode);
6202         inode_set_bytes(inode, 0);
6203
6204         inode->i_mtime = current_fs_time(inode->i_sb);
6205         inode->i_atime = inode->i_mtime;
6206         inode->i_ctime = inode->i_mtime;
6207         BTRFS_I(inode)->i_otime = inode->i_mtime;
6208
6209         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6210                                   struct btrfs_inode_item);
6211         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
6212                              sizeof(*inode_item));
6213         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6214
6215         if (name) {
6216                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6217                                      struct btrfs_inode_ref);
6218                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6219                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6220                 ptr = (unsigned long)(ref + 1);
6221                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6222         }
6223
6224         btrfs_mark_buffer_dirty(path->nodes[0]);
6225         btrfs_free_path(path);
6226
6227         btrfs_inherit_iflags(inode, dir);
6228
6229         if (S_ISREG(mode)) {
6230                 if (btrfs_test_opt(root, NODATASUM))
6231                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6232                 if (btrfs_test_opt(root, NODATACOW))
6233                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6234                                 BTRFS_INODE_NODATASUM;
6235         }
6236
6237         inode_tree_add(inode);
6238
6239         trace_btrfs_inode_new(inode);
6240         btrfs_set_inode_last_trans(trans, inode);
6241
6242         btrfs_update_root_times(trans, root);
6243
6244         ret = btrfs_inode_inherit_props(trans, inode, dir);
6245         if (ret)
6246                 btrfs_err(root->fs_info,
6247                           "error inheriting props for ino %llu (root %llu): %d",
6248                           btrfs_ino(inode), root->root_key.objectid, ret);
6249
6250         return inode;
6251
6252 fail_unlock:
6253         unlock_new_inode(inode);
6254 fail:
6255         if (dir && name)
6256                 BTRFS_I(dir)->index_cnt--;
6257         btrfs_free_path(path);
6258         iput(inode);
6259         return ERR_PTR(ret);
6260 }
6261
6262 static inline u8 btrfs_inode_type(struct inode *inode)
6263 {
6264         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6265 }
6266
6267 /*
6268  * utility function to add 'inode' into 'parent_inode' with
6269  * a give name and a given sequence number.
6270  * if 'add_backref' is true, also insert a backref from the
6271  * inode to the parent directory.
6272  */
6273 int btrfs_add_link(struct btrfs_trans_handle *trans,
6274                    struct inode *parent_inode, struct inode *inode,
6275                    const char *name, int name_len, int add_backref, u64 index)
6276 {
6277         int ret = 0;
6278         struct btrfs_key key;
6279         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6280         u64 ino = btrfs_ino(inode);
6281         u64 parent_ino = btrfs_ino(parent_inode);
6282
6283         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6284                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6285         } else {
6286                 key.objectid = ino;
6287                 key.type = BTRFS_INODE_ITEM_KEY;
6288                 key.offset = 0;
6289         }
6290
6291         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6292                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
6293                                          key.objectid, root->root_key.objectid,
6294                                          parent_ino, index, name, name_len);
6295         } else if (add_backref) {
6296                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6297                                              parent_ino, index);
6298         }
6299
6300         /* Nothing to clean up yet */
6301         if (ret)
6302                 return ret;
6303
6304         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6305                                     parent_inode, &key,
6306                                     btrfs_inode_type(inode), index);
6307         if (ret == -EEXIST || ret == -EOVERFLOW)
6308                 goto fail_dir_item;
6309         else if (ret) {
6310                 btrfs_abort_transaction(trans, root, ret);
6311                 return ret;
6312         }
6313
6314         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6315                            name_len * 2);
6316         inode_inc_iversion(parent_inode);
6317         parent_inode->i_mtime = parent_inode->i_ctime =
6318                 current_fs_time(parent_inode->i_sb);
6319         ret = btrfs_update_inode(trans, root, parent_inode);
6320         if (ret)
6321                 btrfs_abort_transaction(trans, root, ret);
6322         return ret;
6323
6324 fail_dir_item:
6325         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6326                 u64 local_index;
6327                 int err;
6328                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
6329                                  key.objectid, root->root_key.objectid,
6330                                  parent_ino, &local_index, name, name_len);
6331
6332         } else if (add_backref) {
6333                 u64 local_index;
6334                 int err;
6335
6336                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6337                                           ino, parent_ino, &local_index);
6338         }
6339         return ret;
6340 }
6341
6342 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6343                             struct inode *dir, struct dentry *dentry,
6344                             struct inode *inode, int backref, u64 index)
6345 {
6346         int err = btrfs_add_link(trans, dir, inode,
6347                                  dentry->d_name.name, dentry->d_name.len,
6348                                  backref, index);
6349         if (err > 0)
6350                 err = -EEXIST;
6351         return err;
6352 }
6353
6354 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6355                         umode_t mode, dev_t rdev)
6356 {
6357         struct btrfs_trans_handle *trans;
6358         struct btrfs_root *root = BTRFS_I(dir)->root;
6359         struct inode *inode = NULL;
6360         int err;
6361         int drop_inode = 0;
6362         u64 objectid;
6363         u64 index = 0;
6364
6365         /*
6366          * 2 for inode item and ref
6367          * 2 for dir items
6368          * 1 for xattr if selinux is on
6369          */
6370         trans = btrfs_start_transaction(root, 5);
6371         if (IS_ERR(trans))
6372                 return PTR_ERR(trans);
6373
6374         err = btrfs_find_free_ino(root, &objectid);
6375         if (err)
6376                 goto out_unlock;
6377
6378         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6379                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6380                                 mode, &index);
6381         if (IS_ERR(inode)) {
6382                 err = PTR_ERR(inode);
6383                 goto out_unlock;
6384         }
6385
6386         /*
6387         * If the active LSM wants to access the inode during
6388         * d_instantiate it needs these. Smack checks to see
6389         * if the filesystem supports xattrs by looking at the
6390         * ops vector.
6391         */
6392         inode->i_op = &btrfs_special_inode_operations;
6393         init_special_inode(inode, inode->i_mode, rdev);
6394
6395         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6396         if (err)
6397                 goto out_unlock_inode;
6398
6399         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6400         if (err) {
6401                 goto out_unlock_inode;
6402         } else {
6403                 btrfs_update_inode(trans, root, inode);
6404                 unlock_new_inode(inode);
6405                 d_instantiate(dentry, inode);
6406         }
6407
6408 out_unlock:
6409         btrfs_end_transaction(trans, root);
6410         btrfs_balance_delayed_items(root);
6411         btrfs_btree_balance_dirty(root);
6412         if (drop_inode) {
6413                 inode_dec_link_count(inode);
6414                 iput(inode);
6415         }
6416         return err;
6417
6418 out_unlock_inode:
6419         drop_inode = 1;
6420         unlock_new_inode(inode);
6421         goto out_unlock;
6422
6423 }
6424
6425 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6426                         umode_t mode, bool excl)
6427 {
6428         struct btrfs_trans_handle *trans;
6429         struct btrfs_root *root = BTRFS_I(dir)->root;
6430         struct inode *inode = NULL;
6431         int drop_inode_on_err = 0;
6432         int err;
6433         u64 objectid;
6434         u64 index = 0;
6435
6436         /*
6437          * 2 for inode item and ref
6438          * 2 for dir items
6439          * 1 for xattr if selinux is on
6440          */
6441         trans = btrfs_start_transaction(root, 5);
6442         if (IS_ERR(trans))
6443                 return PTR_ERR(trans);
6444
6445         err = btrfs_find_free_ino(root, &objectid);
6446         if (err)
6447                 goto out_unlock;
6448
6449         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6450                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6451                                 mode, &index);
6452         if (IS_ERR(inode)) {
6453                 err = PTR_ERR(inode);
6454                 goto out_unlock;
6455         }
6456         drop_inode_on_err = 1;
6457         /*
6458         * If the active LSM wants to access the inode during
6459         * d_instantiate it needs these. Smack checks to see
6460         * if the filesystem supports xattrs by looking at the
6461         * ops vector.
6462         */
6463         inode->i_fop = &btrfs_file_operations;
6464         inode->i_op = &btrfs_file_inode_operations;
6465         inode->i_mapping->a_ops = &btrfs_aops;
6466
6467         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6468         if (err)
6469                 goto out_unlock_inode;
6470
6471         err = btrfs_update_inode(trans, root, inode);
6472         if (err)
6473                 goto out_unlock_inode;
6474
6475         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6476         if (err)
6477                 goto out_unlock_inode;
6478
6479         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6480         unlock_new_inode(inode);
6481         d_instantiate(dentry, inode);
6482
6483 out_unlock:
6484         btrfs_end_transaction(trans, root);
6485         if (err && drop_inode_on_err) {
6486                 inode_dec_link_count(inode);
6487                 iput(inode);
6488         }
6489         btrfs_balance_delayed_items(root);
6490         btrfs_btree_balance_dirty(root);
6491         return err;
6492
6493 out_unlock_inode:
6494         unlock_new_inode(inode);
6495         goto out_unlock;
6496
6497 }
6498
6499 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6500                       struct dentry *dentry)
6501 {
6502         struct btrfs_trans_handle *trans = NULL;
6503         struct btrfs_root *root = BTRFS_I(dir)->root;
6504         struct inode *inode = d_inode(old_dentry);
6505         u64 index;
6506         int err;
6507         int drop_inode = 0;
6508
6509         /* do not allow sys_link's with other subvols of the same device */
6510         if (root->objectid != BTRFS_I(inode)->root->objectid)
6511                 return -EXDEV;
6512
6513         if (inode->i_nlink >= BTRFS_LINK_MAX)
6514                 return -EMLINK;
6515
6516         err = btrfs_set_inode_index(dir, &index);
6517         if (err)
6518                 goto fail;
6519
6520         /*
6521          * 2 items for inode and inode ref
6522          * 2 items for dir items
6523          * 1 item for parent inode
6524          */
6525         trans = btrfs_start_transaction(root, 5);
6526         if (IS_ERR(trans)) {
6527                 err = PTR_ERR(trans);
6528                 trans = NULL;
6529                 goto fail;
6530         }
6531
6532         /* There are several dir indexes for this inode, clear the cache. */
6533         BTRFS_I(inode)->dir_index = 0ULL;
6534         inc_nlink(inode);
6535         inode_inc_iversion(inode);
6536         inode->i_ctime = current_fs_time(inode->i_sb);
6537         ihold(inode);
6538         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6539
6540         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6541
6542         if (err) {
6543                 drop_inode = 1;
6544         } else {
6545                 struct dentry *parent = dentry->d_parent;
6546                 err = btrfs_update_inode(trans, root, inode);
6547                 if (err)
6548                         goto fail;
6549                 if (inode->i_nlink == 1) {
6550                         /*
6551                          * If new hard link count is 1, it's a file created
6552                          * with open(2) O_TMPFILE flag.
6553                          */
6554                         err = btrfs_orphan_del(trans, inode);
6555                         if (err)
6556                                 goto fail;
6557                 }
6558                 d_instantiate(dentry, inode);
6559                 btrfs_log_new_name(trans, inode, NULL, parent);
6560         }
6561
6562         btrfs_balance_delayed_items(root);
6563 fail:
6564         if (trans)
6565                 btrfs_end_transaction(trans, root);
6566         if (drop_inode) {
6567                 inode_dec_link_count(inode);
6568                 iput(inode);
6569         }
6570         btrfs_btree_balance_dirty(root);
6571         return err;
6572 }
6573
6574 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6575 {
6576         struct inode *inode = NULL;
6577         struct btrfs_trans_handle *trans;
6578         struct btrfs_root *root = BTRFS_I(dir)->root;
6579         int err = 0;
6580         int drop_on_err = 0;
6581         u64 objectid = 0;
6582         u64 index = 0;
6583
6584         /*
6585          * 2 items for inode and ref
6586          * 2 items for dir items
6587          * 1 for xattr if selinux is on
6588          */
6589         trans = btrfs_start_transaction(root, 5);
6590         if (IS_ERR(trans))
6591                 return PTR_ERR(trans);
6592
6593         err = btrfs_find_free_ino(root, &objectid);
6594         if (err)
6595                 goto out_fail;
6596
6597         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6598                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6599                                 S_IFDIR | mode, &index);
6600         if (IS_ERR(inode)) {
6601                 err = PTR_ERR(inode);
6602                 goto out_fail;
6603         }
6604
6605         drop_on_err = 1;
6606         /* these must be set before we unlock the inode */
6607         inode->i_op = &btrfs_dir_inode_operations;
6608         inode->i_fop = &btrfs_dir_file_operations;
6609
6610         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6611         if (err)
6612                 goto out_fail_inode;
6613
6614         btrfs_i_size_write(inode, 0);
6615         err = btrfs_update_inode(trans, root, inode);
6616         if (err)
6617                 goto out_fail_inode;
6618
6619         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6620                              dentry->d_name.len, 0, index);
6621         if (err)
6622                 goto out_fail_inode;
6623
6624         d_instantiate(dentry, inode);
6625         /*
6626          * mkdir is special.  We're unlocking after we call d_instantiate
6627          * to avoid a race with nfsd calling d_instantiate.
6628          */
6629         unlock_new_inode(inode);
6630         drop_on_err = 0;
6631
6632 out_fail:
6633         btrfs_end_transaction(trans, root);
6634         if (drop_on_err) {
6635                 inode_dec_link_count(inode);
6636                 iput(inode);
6637         }
6638         btrfs_balance_delayed_items(root);
6639         btrfs_btree_balance_dirty(root);
6640         return err;
6641
6642 out_fail_inode:
6643         unlock_new_inode(inode);
6644         goto out_fail;
6645 }
6646
6647 /* Find next extent map of a given extent map, caller needs to ensure locks */
6648 static struct extent_map *next_extent_map(struct extent_map *em)
6649 {
6650         struct rb_node *next;
6651
6652         next = rb_next(&em->rb_node);
6653         if (!next)
6654                 return NULL;
6655         return container_of(next, struct extent_map, rb_node);
6656 }
6657
6658 static struct extent_map *prev_extent_map(struct extent_map *em)
6659 {
6660         struct rb_node *prev;
6661
6662         prev = rb_prev(&em->rb_node);
6663         if (!prev)
6664                 return NULL;
6665         return container_of(prev, struct extent_map, rb_node);
6666 }
6667
6668 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6669  * the existing extent is the nearest extent to map_start,
6670  * and an extent that you want to insert, deal with overlap and insert
6671  * the best fitted new extent into the tree.
6672  */
6673 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6674                                 struct extent_map *existing,
6675                                 struct extent_map *em,
6676                                 u64 map_start)
6677 {
6678         struct extent_map *prev;
6679         struct extent_map *next;
6680         u64 start;
6681         u64 end;
6682         u64 start_diff;
6683
6684         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6685
6686         if (existing->start > map_start) {
6687                 next = existing;
6688                 prev = prev_extent_map(next);
6689         } else {
6690                 prev = existing;
6691                 next = next_extent_map(prev);
6692         }
6693
6694         start = prev ? extent_map_end(prev) : em->start;
6695         start = max_t(u64, start, em->start);
6696         end = next ? next->start : extent_map_end(em);
6697         end = min_t(u64, end, extent_map_end(em));
6698         start_diff = start - em->start;
6699         em->start = start;
6700         em->len = end - start;
6701         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6702             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6703                 em->block_start += start_diff;
6704                 em->block_len -= start_diff;
6705         }
6706         return add_extent_mapping(em_tree, em, 0);
6707 }
6708
6709 static noinline int uncompress_inline(struct btrfs_path *path,
6710                                       struct page *page,
6711                                       size_t pg_offset, u64 extent_offset,
6712                                       struct btrfs_file_extent_item *item)
6713 {
6714         int ret;
6715         struct extent_buffer *leaf = path->nodes[0];
6716         char *tmp;
6717         size_t max_size;
6718         unsigned long inline_size;
6719         unsigned long ptr;
6720         int compress_type;
6721
6722         WARN_ON(pg_offset != 0);
6723         compress_type = btrfs_file_extent_compression(leaf, item);
6724         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6725         inline_size = btrfs_file_extent_inline_item_len(leaf,
6726                                         btrfs_item_nr(path->slots[0]));
6727         tmp = kmalloc(inline_size, GFP_NOFS);
6728         if (!tmp)
6729                 return -ENOMEM;
6730         ptr = btrfs_file_extent_inline_start(item);
6731
6732         read_extent_buffer(leaf, tmp, ptr, inline_size);
6733
6734         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6735         ret = btrfs_decompress(compress_type, tmp, page,
6736                                extent_offset, inline_size, max_size);
6737         kfree(tmp);
6738         return ret;
6739 }
6740
6741 /*
6742  * a bit scary, this does extent mapping from logical file offset to the disk.
6743  * the ugly parts come from merging extents from the disk with the in-ram
6744  * representation.  This gets more complex because of the data=ordered code,
6745  * where the in-ram extents might be locked pending data=ordered completion.
6746  *
6747  * This also copies inline extents directly into the page.
6748  */
6749
6750 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6751                                     size_t pg_offset, u64 start, u64 len,
6752                                     int create)
6753 {
6754         int ret;
6755         int err = 0;
6756         u64 extent_start = 0;
6757         u64 extent_end = 0;
6758         u64 objectid = btrfs_ino(inode);
6759         u32 found_type;
6760         struct btrfs_path *path = NULL;
6761         struct btrfs_root *root = BTRFS_I(inode)->root;
6762         struct btrfs_file_extent_item *item;
6763         struct extent_buffer *leaf;
6764         struct btrfs_key found_key;
6765         struct extent_map *em = NULL;
6766         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6767         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6768         struct btrfs_trans_handle *trans = NULL;
6769         const bool new_inline = !page || create;
6770
6771 again:
6772         read_lock(&em_tree->lock);
6773         em = lookup_extent_mapping(em_tree, start, len);
6774         if (em)
6775                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6776         read_unlock(&em_tree->lock);
6777
6778         if (em) {
6779                 if (em->start > start || em->start + em->len <= start)
6780                         free_extent_map(em);
6781                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6782                         free_extent_map(em);
6783                 else
6784                         goto out;
6785         }
6786         em = alloc_extent_map();
6787         if (!em) {
6788                 err = -ENOMEM;
6789                 goto out;
6790         }
6791         em->bdev = root->fs_info->fs_devices->latest_bdev;
6792         em->start = EXTENT_MAP_HOLE;
6793         em->orig_start = EXTENT_MAP_HOLE;
6794         em->len = (u64)-1;
6795         em->block_len = (u64)-1;
6796
6797         if (!path) {
6798                 path = btrfs_alloc_path();
6799                 if (!path) {
6800                         err = -ENOMEM;
6801                         goto out;
6802                 }
6803                 /*
6804                  * Chances are we'll be called again, so go ahead and do
6805                  * readahead
6806                  */
6807                 path->reada = READA_FORWARD;
6808         }
6809
6810         ret = btrfs_lookup_file_extent(trans, root, path,
6811                                        objectid, start, trans != NULL);
6812         if (ret < 0) {
6813                 err = ret;
6814                 goto out;
6815         }
6816
6817         if (ret != 0) {
6818                 if (path->slots[0] == 0)
6819                         goto not_found;
6820                 path->slots[0]--;
6821         }
6822
6823         leaf = path->nodes[0];
6824         item = btrfs_item_ptr(leaf, path->slots[0],
6825                               struct btrfs_file_extent_item);
6826         /* are we inside the extent that was found? */
6827         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6828         found_type = found_key.type;
6829         if (found_key.objectid != objectid ||
6830             found_type != BTRFS_EXTENT_DATA_KEY) {
6831                 /*
6832                  * If we backup past the first extent we want to move forward
6833                  * and see if there is an extent in front of us, otherwise we'll
6834                  * say there is a hole for our whole search range which can
6835                  * cause problems.
6836                  */
6837                 extent_end = start;
6838                 goto next;
6839         }
6840
6841         found_type = btrfs_file_extent_type(leaf, item);
6842         extent_start = found_key.offset;
6843         if (found_type == BTRFS_FILE_EXTENT_REG ||
6844             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6845                 extent_end = extent_start +
6846                        btrfs_file_extent_num_bytes(leaf, item);
6847         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6848                 size_t size;
6849                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6850                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6851         }
6852 next:
6853         if (start >= extent_end) {
6854                 path->slots[0]++;
6855                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6856                         ret = btrfs_next_leaf(root, path);
6857                         if (ret < 0) {
6858                                 err = ret;
6859                                 goto out;
6860                         }
6861                         if (ret > 0)
6862                                 goto not_found;
6863                         leaf = path->nodes[0];
6864                 }
6865                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6866                 if (found_key.objectid != objectid ||
6867                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6868                         goto not_found;
6869                 if (start + len <= found_key.offset)
6870                         goto not_found;
6871                 if (start > found_key.offset)
6872                         goto next;
6873                 em->start = start;
6874                 em->orig_start = start;
6875                 em->len = found_key.offset - start;
6876                 goto not_found_em;
6877         }
6878
6879         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6880
6881         if (found_type == BTRFS_FILE_EXTENT_REG ||
6882             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6883                 goto insert;
6884         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6885                 unsigned long ptr;
6886                 char *map;
6887                 size_t size;
6888                 size_t extent_offset;
6889                 size_t copy_size;
6890
6891                 if (new_inline)
6892                         goto out;
6893
6894                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6895                 extent_offset = page_offset(page) + pg_offset - extent_start;
6896                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6897                                   size - extent_offset);
6898                 em->start = extent_start + extent_offset;
6899                 em->len = ALIGN(copy_size, root->sectorsize);
6900                 em->orig_block_len = em->len;
6901                 em->orig_start = em->start;
6902                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6903                 if (create == 0 && !PageUptodate(page)) {
6904                         if (btrfs_file_extent_compression(leaf, item) !=
6905                             BTRFS_COMPRESS_NONE) {
6906                                 ret = uncompress_inline(path, page, pg_offset,
6907                                                         extent_offset, item);
6908                                 if (ret) {
6909                                         err = ret;
6910                                         goto out;
6911                                 }
6912                         } else {
6913                                 map = kmap(page);
6914                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6915                                                    copy_size);
6916                                 if (pg_offset + copy_size < PAGE_SIZE) {
6917                                         memset(map + pg_offset + copy_size, 0,
6918                                                PAGE_SIZE - pg_offset -
6919                                                copy_size);
6920                                 }
6921                                 kunmap(page);
6922                         }
6923                         flush_dcache_page(page);
6924                 } else if (create && PageUptodate(page)) {
6925                         BUG();
6926                         if (!trans) {
6927                                 kunmap(page);
6928                                 free_extent_map(em);
6929                                 em = NULL;
6930
6931                                 btrfs_release_path(path);
6932                                 trans = btrfs_join_transaction(root);
6933
6934                                 if (IS_ERR(trans))
6935                                         return ERR_CAST(trans);
6936                                 goto again;
6937                         }
6938                         map = kmap(page);
6939                         write_extent_buffer(leaf, map + pg_offset, ptr,
6940                                             copy_size);
6941                         kunmap(page);
6942                         btrfs_mark_buffer_dirty(leaf);
6943                 }
6944                 set_extent_uptodate(io_tree, em->start,
6945                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6946                 goto insert;
6947         }
6948 not_found:
6949         em->start = start;
6950         em->orig_start = start;
6951         em->len = len;
6952 not_found_em:
6953         em->block_start = EXTENT_MAP_HOLE;
6954         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6955 insert:
6956         btrfs_release_path(path);
6957         if (em->start > start || extent_map_end(em) <= start) {
6958                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6959                         em->start, em->len, start, len);
6960                 err = -EIO;
6961                 goto out;
6962         }
6963
6964         err = 0;
6965         write_lock(&em_tree->lock);
6966         ret = add_extent_mapping(em_tree, em, 0);
6967         /* it is possible that someone inserted the extent into the tree
6968          * while we had the lock dropped.  It is also possible that
6969          * an overlapping map exists in the tree
6970          */
6971         if (ret == -EEXIST) {
6972                 struct extent_map *existing;
6973
6974                 ret = 0;
6975
6976                 existing = search_extent_mapping(em_tree, start, len);
6977                 /*
6978                  * existing will always be non-NULL, since there must be
6979                  * extent causing the -EEXIST.
6980                  */
6981                 if (existing->start == em->start &&
6982                     extent_map_end(existing) == extent_map_end(em) &&
6983                     em->block_start == existing->block_start) {
6984                         /*
6985                          * these two extents are the same, it happens
6986                          * with inlines especially
6987                          */
6988                         free_extent_map(em);
6989                         em = existing;
6990                         err = 0;
6991
6992                 } else if (start >= extent_map_end(existing) ||
6993                     start <= existing->start) {
6994                         /*
6995                          * The existing extent map is the one nearest to
6996                          * the [start, start + len) range which overlaps
6997                          */
6998                         err = merge_extent_mapping(em_tree, existing,
6999                                                    em, start);
7000                         free_extent_map(existing);
7001                         if (err) {
7002                                 free_extent_map(em);
7003                                 em = NULL;
7004                         }
7005                 } else {
7006                         free_extent_map(em);
7007                         em = existing;
7008                         err = 0;
7009                 }
7010         }
7011         write_unlock(&em_tree->lock);
7012 out:
7013
7014         trace_btrfs_get_extent(root, em);
7015
7016         btrfs_free_path(path);
7017         if (trans) {
7018                 ret = btrfs_end_transaction(trans, root);
7019                 if (!err)
7020                         err = ret;
7021         }
7022         if (err) {
7023                 free_extent_map(em);
7024                 return ERR_PTR(err);
7025         }
7026         BUG_ON(!em); /* Error is always set */
7027         return em;
7028 }
7029
7030 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7031                                            size_t pg_offset, u64 start, u64 len,
7032                                            int create)
7033 {
7034         struct extent_map *em;
7035         struct extent_map *hole_em = NULL;
7036         u64 range_start = start;
7037         u64 end;
7038         u64 found;
7039         u64 found_end;
7040         int err = 0;
7041
7042         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7043         if (IS_ERR(em))
7044                 return em;
7045         if (em) {
7046                 /*
7047                  * if our em maps to
7048                  * -  a hole or
7049                  * -  a pre-alloc extent,
7050                  * there might actually be delalloc bytes behind it.
7051                  */
7052                 if (em->block_start != EXTENT_MAP_HOLE &&
7053                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7054                         return em;
7055                 else
7056                         hole_em = em;
7057         }
7058
7059         /* check to see if we've wrapped (len == -1 or similar) */
7060         end = start + len;
7061         if (end < start)
7062                 end = (u64)-1;
7063         else
7064                 end -= 1;
7065
7066         em = NULL;
7067
7068         /* ok, we didn't find anything, lets look for delalloc */
7069         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7070                                  end, len, EXTENT_DELALLOC, 1);
7071         found_end = range_start + found;
7072         if (found_end < range_start)
7073                 found_end = (u64)-1;
7074
7075         /*
7076          * we didn't find anything useful, return
7077          * the original results from get_extent()
7078          */
7079         if (range_start > end || found_end <= start) {
7080                 em = hole_em;
7081                 hole_em = NULL;
7082                 goto out;
7083         }
7084
7085         /* adjust the range_start to make sure it doesn't
7086          * go backwards from the start they passed in
7087          */
7088         range_start = max(start, range_start);
7089         found = found_end - range_start;
7090
7091         if (found > 0) {
7092                 u64 hole_start = start;
7093                 u64 hole_len = len;
7094
7095                 em = alloc_extent_map();
7096                 if (!em) {
7097                         err = -ENOMEM;
7098                         goto out;
7099                 }
7100                 /*
7101                  * when btrfs_get_extent can't find anything it
7102                  * returns one huge hole
7103                  *
7104                  * make sure what it found really fits our range, and
7105                  * adjust to make sure it is based on the start from
7106                  * the caller
7107                  */
7108                 if (hole_em) {
7109                         u64 calc_end = extent_map_end(hole_em);
7110
7111                         if (calc_end <= start || (hole_em->start > end)) {
7112                                 free_extent_map(hole_em);
7113                                 hole_em = NULL;
7114                         } else {
7115                                 hole_start = max(hole_em->start, start);
7116                                 hole_len = calc_end - hole_start;
7117                         }
7118                 }
7119                 em->bdev = NULL;
7120                 if (hole_em && range_start > hole_start) {
7121                         /* our hole starts before our delalloc, so we
7122                          * have to return just the parts of the hole
7123                          * that go until  the delalloc starts
7124                          */
7125                         em->len = min(hole_len,
7126                                       range_start - hole_start);
7127                         em->start = hole_start;
7128                         em->orig_start = hole_start;
7129                         /*
7130                          * don't adjust block start at all,
7131                          * it is fixed at EXTENT_MAP_HOLE
7132                          */
7133                         em->block_start = hole_em->block_start;
7134                         em->block_len = hole_len;
7135                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7136                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7137                 } else {
7138                         em->start = range_start;
7139                         em->len = found;
7140                         em->orig_start = range_start;
7141                         em->block_start = EXTENT_MAP_DELALLOC;
7142                         em->block_len = found;
7143                 }
7144         } else if (hole_em) {
7145                 return hole_em;
7146         }
7147 out:
7148
7149         free_extent_map(hole_em);
7150         if (err) {
7151                 free_extent_map(em);
7152                 return ERR_PTR(err);
7153         }
7154         return em;
7155 }
7156
7157 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7158                                                   const u64 start,
7159                                                   const u64 len,
7160                                                   const u64 orig_start,
7161                                                   const u64 block_start,
7162                                                   const u64 block_len,
7163                                                   const u64 orig_block_len,
7164                                                   const u64 ram_bytes,
7165                                                   const int type)
7166 {
7167         struct extent_map *em = NULL;
7168         int ret;
7169
7170         down_read(&BTRFS_I(inode)->dio_sem);
7171         if (type != BTRFS_ORDERED_NOCOW) {
7172                 em = create_pinned_em(inode, start, len, orig_start,
7173                                       block_start, block_len, orig_block_len,
7174                                       ram_bytes, type);
7175                 if (IS_ERR(em))
7176                         goto out;
7177         }
7178         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7179                                            len, block_len, type);
7180         if (ret) {
7181                 if (em) {
7182                         free_extent_map(em);
7183                         btrfs_drop_extent_cache(inode, start,
7184                                                 start + len - 1, 0);
7185                 }
7186                 em = ERR_PTR(ret);
7187         }
7188  out:
7189         up_read(&BTRFS_I(inode)->dio_sem);
7190
7191         return em;
7192 }
7193
7194 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7195                                                   u64 start, u64 len)
7196 {
7197         struct btrfs_root *root = BTRFS_I(inode)->root;
7198         struct extent_map *em;
7199         struct btrfs_key ins;
7200         u64 alloc_hint;
7201         int ret;
7202
7203         alloc_hint = get_extent_allocation_hint(inode, start, len);
7204         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
7205                                    alloc_hint, &ins, 1, 1);
7206         if (ret)
7207                 return ERR_PTR(ret);
7208
7209         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7210                                      ins.objectid, ins.offset, ins.offset,
7211                                      ins.offset, 0);
7212         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
7213         if (IS_ERR(em))
7214                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7215
7216         return em;
7217 }
7218
7219 /*
7220  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7221  * block must be cow'd
7222  */
7223 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7224                               u64 *orig_start, u64 *orig_block_len,
7225                               u64 *ram_bytes)
7226 {
7227         struct btrfs_trans_handle *trans;
7228         struct btrfs_path *path;
7229         int ret;
7230         struct extent_buffer *leaf;
7231         struct btrfs_root *root = BTRFS_I(inode)->root;
7232         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7233         struct btrfs_file_extent_item *fi;
7234         struct btrfs_key key;
7235         u64 disk_bytenr;
7236         u64 backref_offset;
7237         u64 extent_end;
7238         u64 num_bytes;
7239         int slot;
7240         int found_type;
7241         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7242
7243         path = btrfs_alloc_path();
7244         if (!path)
7245                 return -ENOMEM;
7246
7247         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
7248                                        offset, 0);
7249         if (ret < 0)
7250                 goto out;
7251
7252         slot = path->slots[0];
7253         if (ret == 1) {
7254                 if (slot == 0) {
7255                         /* can't find the item, must cow */
7256                         ret = 0;
7257                         goto out;
7258                 }
7259                 slot--;
7260         }
7261         ret = 0;
7262         leaf = path->nodes[0];
7263         btrfs_item_key_to_cpu(leaf, &key, slot);
7264         if (key.objectid != btrfs_ino(inode) ||
7265             key.type != BTRFS_EXTENT_DATA_KEY) {
7266                 /* not our file or wrong item type, must cow */
7267                 goto out;
7268         }
7269
7270         if (key.offset > offset) {
7271                 /* Wrong offset, must cow */
7272                 goto out;
7273         }
7274
7275         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7276         found_type = btrfs_file_extent_type(leaf, fi);
7277         if (found_type != BTRFS_FILE_EXTENT_REG &&
7278             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7279                 /* not a regular extent, must cow */
7280                 goto out;
7281         }
7282
7283         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7284                 goto out;
7285
7286         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7287         if (extent_end <= offset)
7288                 goto out;
7289
7290         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7291         if (disk_bytenr == 0)
7292                 goto out;
7293
7294         if (btrfs_file_extent_compression(leaf, fi) ||
7295             btrfs_file_extent_encryption(leaf, fi) ||
7296             btrfs_file_extent_other_encoding(leaf, fi))
7297                 goto out;
7298
7299         backref_offset = btrfs_file_extent_offset(leaf, fi);
7300
7301         if (orig_start) {
7302                 *orig_start = key.offset - backref_offset;
7303                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7304                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7305         }
7306
7307         if (btrfs_extent_readonly(root, disk_bytenr))
7308                 goto out;
7309
7310         num_bytes = min(offset + *len, extent_end) - offset;
7311         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7312                 u64 range_end;
7313
7314                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
7315                 ret = test_range_bit(io_tree, offset, range_end,
7316                                      EXTENT_DELALLOC, 0, NULL);
7317                 if (ret) {
7318                         ret = -EAGAIN;
7319                         goto out;
7320                 }
7321         }
7322
7323         btrfs_release_path(path);
7324
7325         /*
7326          * look for other files referencing this extent, if we
7327          * find any we must cow
7328          */
7329         trans = btrfs_join_transaction(root);
7330         if (IS_ERR(trans)) {
7331                 ret = 0;
7332                 goto out;
7333         }
7334
7335         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
7336                                     key.offset - backref_offset, disk_bytenr);
7337         btrfs_end_transaction(trans, root);
7338         if (ret) {
7339                 ret = 0;
7340                 goto out;
7341         }
7342
7343         /*
7344          * adjust disk_bytenr and num_bytes to cover just the bytes
7345          * in this extent we are about to write.  If there
7346          * are any csums in that range we have to cow in order
7347          * to keep the csums correct
7348          */
7349         disk_bytenr += backref_offset;
7350         disk_bytenr += offset - key.offset;
7351         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
7352                                 goto out;
7353         /*
7354          * all of the above have passed, it is safe to overwrite this extent
7355          * without cow
7356          */
7357         *len = num_bytes;
7358         ret = 1;
7359 out:
7360         btrfs_free_path(path);
7361         return ret;
7362 }
7363
7364 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7365 {
7366         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7367         int found = false;
7368         void **pagep = NULL;
7369         struct page *page = NULL;
7370         int start_idx;
7371         int end_idx;
7372
7373         start_idx = start >> PAGE_SHIFT;
7374
7375         /*
7376          * end is the last byte in the last page.  end == start is legal
7377          */
7378         end_idx = end >> PAGE_SHIFT;
7379
7380         rcu_read_lock();
7381
7382         /* Most of the code in this while loop is lifted from
7383          * find_get_page.  It's been modified to begin searching from a
7384          * page and return just the first page found in that range.  If the
7385          * found idx is less than or equal to the end idx then we know that
7386          * a page exists.  If no pages are found or if those pages are
7387          * outside of the range then we're fine (yay!) */
7388         while (page == NULL &&
7389                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7390                 page = radix_tree_deref_slot(pagep);
7391                 if (unlikely(!page))
7392                         break;
7393
7394                 if (radix_tree_exception(page)) {
7395                         if (radix_tree_deref_retry(page)) {
7396                                 page = NULL;
7397                                 continue;
7398                         }
7399                         /*
7400                          * Otherwise, shmem/tmpfs must be storing a swap entry
7401                          * here as an exceptional entry: so return it without
7402                          * attempting to raise page count.
7403                          */
7404                         page = NULL;
7405                         break; /* TODO: Is this relevant for this use case? */
7406                 }
7407
7408                 if (!page_cache_get_speculative(page)) {
7409                         page = NULL;
7410                         continue;
7411                 }
7412
7413                 /*
7414                  * Has the page moved?
7415                  * This is part of the lockless pagecache protocol. See
7416                  * include/linux/pagemap.h for details.
7417                  */
7418                 if (unlikely(page != *pagep)) {
7419                         put_page(page);
7420                         page = NULL;
7421                 }
7422         }
7423
7424         if (page) {
7425                 if (page->index <= end_idx)
7426                         found = true;
7427                 put_page(page);
7428         }
7429
7430         rcu_read_unlock();
7431         return found;
7432 }
7433
7434 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7435                               struct extent_state **cached_state, int writing)
7436 {
7437         struct btrfs_ordered_extent *ordered;
7438         int ret = 0;
7439
7440         while (1) {
7441                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7442                                  cached_state);
7443                 /*
7444                  * We're concerned with the entire range that we're going to be
7445                  * doing DIO to, so we need to make sure there's no ordered
7446                  * extents in this range.
7447                  */
7448                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7449                                                      lockend - lockstart + 1);
7450
7451                 /*
7452                  * We need to make sure there are no buffered pages in this
7453                  * range either, we could have raced between the invalidate in
7454                  * generic_file_direct_write and locking the extent.  The
7455                  * invalidate needs to happen so that reads after a write do not
7456                  * get stale data.
7457                  */
7458                 if (!ordered &&
7459                     (!writing ||
7460                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7461                         break;
7462
7463                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7464                                      cached_state, GFP_NOFS);
7465
7466                 if (ordered) {
7467                         /*
7468                          * If we are doing a DIO read and the ordered extent we
7469                          * found is for a buffered write, we can not wait for it
7470                          * to complete and retry, because if we do so we can
7471                          * deadlock with concurrent buffered writes on page
7472                          * locks. This happens only if our DIO read covers more
7473                          * than one extent map, if at this point has already
7474                          * created an ordered extent for a previous extent map
7475                          * and locked its range in the inode's io tree, and a
7476                          * concurrent write against that previous extent map's
7477                          * range and this range started (we unlock the ranges
7478                          * in the io tree only when the bios complete and
7479                          * buffered writes always lock pages before attempting
7480                          * to lock range in the io tree).
7481                          */
7482                         if (writing ||
7483                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7484                                 btrfs_start_ordered_extent(inode, ordered, 1);
7485                         else
7486                                 ret = -ENOTBLK;
7487                         btrfs_put_ordered_extent(ordered);
7488                 } else {
7489                         /*
7490                          * We could trigger writeback for this range (and wait
7491                          * for it to complete) and then invalidate the pages for
7492                          * this range (through invalidate_inode_pages2_range()),
7493                          * but that can lead us to a deadlock with a concurrent
7494                          * call to readpages() (a buffered read or a defrag call
7495                          * triggered a readahead) on a page lock due to an
7496                          * ordered dio extent we created before but did not have
7497                          * yet a corresponding bio submitted (whence it can not
7498                          * complete), which makes readpages() wait for that
7499                          * ordered extent to complete while holding a lock on
7500                          * that page.
7501                          */
7502                         ret = -ENOTBLK;
7503                 }
7504
7505                 if (ret)
7506                         break;
7507
7508                 cond_resched();
7509         }
7510
7511         return ret;
7512 }
7513
7514 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7515                                            u64 len, u64 orig_start,
7516                                            u64 block_start, u64 block_len,
7517                                            u64 orig_block_len, u64 ram_bytes,
7518                                            int type)
7519 {
7520         struct extent_map_tree *em_tree;
7521         struct extent_map *em;
7522         struct btrfs_root *root = BTRFS_I(inode)->root;
7523         int ret;
7524
7525         em_tree = &BTRFS_I(inode)->extent_tree;
7526         em = alloc_extent_map();
7527         if (!em)
7528                 return ERR_PTR(-ENOMEM);
7529
7530         em->start = start;
7531         em->orig_start = orig_start;
7532         em->mod_start = start;
7533         em->mod_len = len;
7534         em->len = len;
7535         em->block_len = block_len;
7536         em->block_start = block_start;
7537         em->bdev = root->fs_info->fs_devices->latest_bdev;
7538         em->orig_block_len = orig_block_len;
7539         em->ram_bytes = ram_bytes;
7540         em->generation = -1;
7541         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7542         if (type == BTRFS_ORDERED_PREALLOC)
7543                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7544
7545         do {
7546                 btrfs_drop_extent_cache(inode, em->start,
7547                                 em->start + em->len - 1, 0);
7548                 write_lock(&em_tree->lock);
7549                 ret = add_extent_mapping(em_tree, em, 1);
7550                 write_unlock(&em_tree->lock);
7551         } while (ret == -EEXIST);
7552
7553         if (ret) {
7554                 free_extent_map(em);
7555                 return ERR_PTR(ret);
7556         }
7557
7558         return em;
7559 }
7560
7561 static void adjust_dio_outstanding_extents(struct inode *inode,
7562                                            struct btrfs_dio_data *dio_data,
7563                                            const u64 len)
7564 {
7565         unsigned num_extents;
7566
7567         num_extents = (unsigned) div64_u64(len + BTRFS_MAX_EXTENT_SIZE - 1,
7568                                            BTRFS_MAX_EXTENT_SIZE);
7569         /*
7570          * If we have an outstanding_extents count still set then we're
7571          * within our reservation, otherwise we need to adjust our inode
7572          * counter appropriately.
7573          */
7574         if (dio_data->outstanding_extents) {
7575                 dio_data->outstanding_extents -= num_extents;
7576         } else {
7577                 spin_lock(&BTRFS_I(inode)->lock);
7578                 BTRFS_I(inode)->outstanding_extents += num_extents;
7579                 spin_unlock(&BTRFS_I(inode)->lock);
7580         }
7581 }
7582
7583 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7584                                    struct buffer_head *bh_result, int create)
7585 {
7586         struct extent_map *em;
7587         struct btrfs_root *root = BTRFS_I(inode)->root;
7588         struct extent_state *cached_state = NULL;
7589         struct btrfs_dio_data *dio_data = NULL;
7590         u64 start = iblock << inode->i_blkbits;
7591         u64 lockstart, lockend;
7592         u64 len = bh_result->b_size;
7593         int unlock_bits = EXTENT_LOCKED;
7594         int ret = 0;
7595
7596         if (create)
7597                 unlock_bits |= EXTENT_DIRTY;
7598         else
7599                 len = min_t(u64, len, root->sectorsize);
7600
7601         lockstart = start;
7602         lockend = start + len - 1;
7603
7604         if (current->journal_info) {
7605                 /*
7606                  * Need to pull our outstanding extents and set journal_info to NULL so
7607                  * that anything that needs to check if there's a transaction doesn't get
7608                  * confused.
7609                  */
7610                 dio_data = current->journal_info;
7611                 current->journal_info = NULL;
7612         }
7613
7614         /*
7615          * If this errors out it's because we couldn't invalidate pagecache for
7616          * this range and we need to fallback to buffered.
7617          */
7618         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7619                                create)) {
7620                 ret = -ENOTBLK;
7621                 goto err;
7622         }
7623
7624         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7625         if (IS_ERR(em)) {
7626                 ret = PTR_ERR(em);
7627                 goto unlock_err;
7628         }
7629
7630         /*
7631          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7632          * io.  INLINE is special, and we could probably kludge it in here, but
7633          * it's still buffered so for safety lets just fall back to the generic
7634          * buffered path.
7635          *
7636          * For COMPRESSED we _have_ to read the entire extent in so we can
7637          * decompress it, so there will be buffering required no matter what we
7638          * do, so go ahead and fallback to buffered.
7639          *
7640          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7641          * to buffered IO.  Don't blame me, this is the price we pay for using
7642          * the generic code.
7643          */
7644         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7645             em->block_start == EXTENT_MAP_INLINE) {
7646                 free_extent_map(em);
7647                 ret = -ENOTBLK;
7648                 goto unlock_err;
7649         }
7650
7651         /* Just a good old fashioned hole, return */
7652         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7653                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7654                 free_extent_map(em);
7655                 goto unlock_err;
7656         }
7657
7658         /*
7659          * We don't allocate a new extent in the following cases
7660          *
7661          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7662          * existing extent.
7663          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7664          * just use the extent.
7665          *
7666          */
7667         if (!create) {
7668                 len = min(len, em->len - (start - em->start));
7669                 lockstart = start + len;
7670                 goto unlock;
7671         }
7672
7673         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7674             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7675              em->block_start != EXTENT_MAP_HOLE)) {
7676                 int type;
7677                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7678
7679                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7680                         type = BTRFS_ORDERED_PREALLOC;
7681                 else
7682                         type = BTRFS_ORDERED_NOCOW;
7683                 len = min(len, em->len - (start - em->start));
7684                 block_start = em->block_start + (start - em->start);
7685
7686                 if (can_nocow_extent(inode, start, &len, &orig_start,
7687                                      &orig_block_len, &ram_bytes) == 1 &&
7688                     btrfs_inc_nocow_writers(root->fs_info, block_start)) {
7689                         struct extent_map *em2;
7690
7691                         em2 = btrfs_create_dio_extent(inode, start, len,
7692                                                       orig_start, block_start,
7693                                                       len, orig_block_len,
7694                                                       ram_bytes, type);
7695                         btrfs_dec_nocow_writers(root->fs_info, block_start);
7696                         if (type == BTRFS_ORDERED_PREALLOC) {
7697                                 free_extent_map(em);
7698                                 em = em2;
7699                         }
7700                         if (em2 && IS_ERR(em2)) {
7701                                 ret = PTR_ERR(em2);
7702                                 goto unlock_err;
7703                         }
7704                         goto unlock;
7705                 }
7706         }
7707
7708         /*
7709          * this will cow the extent, reset the len in case we changed
7710          * it above
7711          */
7712         len = bh_result->b_size;
7713         free_extent_map(em);
7714         em = btrfs_new_extent_direct(inode, start, len);
7715         if (IS_ERR(em)) {
7716                 ret = PTR_ERR(em);
7717                 goto unlock_err;
7718         }
7719         len = min(len, em->len - (start - em->start));
7720 unlock:
7721         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7722                 inode->i_blkbits;
7723         bh_result->b_size = len;
7724         bh_result->b_bdev = em->bdev;
7725         set_buffer_mapped(bh_result);
7726         if (create) {
7727                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7728                         set_buffer_new(bh_result);
7729
7730                 /*
7731                  * Need to update the i_size under the extent lock so buffered
7732                  * readers will get the updated i_size when we unlock.
7733                  */
7734                 if (start + len > i_size_read(inode))
7735                         i_size_write(inode, start + len);
7736
7737                 adjust_dio_outstanding_extents(inode, dio_data, len);
7738                 btrfs_free_reserved_data_space(inode, start, len);
7739                 WARN_ON(dio_data->reserve < len);
7740                 dio_data->reserve -= len;
7741                 dio_data->unsubmitted_oe_range_end = start + len;
7742                 current->journal_info = dio_data;
7743         }
7744
7745         /*
7746          * In the case of write we need to clear and unlock the entire range,
7747          * in the case of read we need to unlock only the end area that we
7748          * aren't using if there is any left over space.
7749          */
7750         if (lockstart < lockend) {
7751                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7752                                  lockend, unlock_bits, 1, 0,
7753                                  &cached_state, GFP_NOFS);
7754         } else {
7755                 free_extent_state(cached_state);
7756         }
7757
7758         free_extent_map(em);
7759
7760         return 0;
7761
7762 unlock_err:
7763         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7764                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7765 err:
7766         if (dio_data)
7767                 current->journal_info = dio_data;
7768         /*
7769          * Compensate the delalloc release we do in btrfs_direct_IO() when we
7770          * write less data then expected, so that we don't underflow our inode's
7771          * outstanding extents counter.
7772          */
7773         if (create && dio_data)
7774                 adjust_dio_outstanding_extents(inode, dio_data, len);
7775
7776         return ret;
7777 }
7778
7779 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7780                                         int mirror_num)
7781 {
7782         struct btrfs_root *root = BTRFS_I(inode)->root;
7783         int ret;
7784
7785         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7786
7787         bio_get(bio);
7788
7789         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7790                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7791         if (ret)
7792                 goto err;
7793
7794         ret = btrfs_map_bio(root, bio, mirror_num, 0);
7795 err:
7796         bio_put(bio);
7797         return ret;
7798 }
7799
7800 static int btrfs_check_dio_repairable(struct inode *inode,
7801                                       struct bio *failed_bio,
7802                                       struct io_failure_record *failrec,
7803                                       int failed_mirror)
7804 {
7805         int num_copies;
7806
7807         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7808                                       failrec->logical, failrec->len);
7809         if (num_copies == 1) {
7810                 /*
7811                  * we only have a single copy of the data, so don't bother with
7812                  * all the retry and error correction code that follows. no
7813                  * matter what the error is, it is very likely to persist.
7814                  */
7815                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7816                          num_copies, failrec->this_mirror, failed_mirror);
7817                 return 0;
7818         }
7819
7820         failrec->failed_mirror = failed_mirror;
7821         failrec->this_mirror++;
7822         if (failrec->this_mirror == failed_mirror)
7823                 failrec->this_mirror++;
7824
7825         if (failrec->this_mirror > num_copies) {
7826                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7827                          num_copies, failrec->this_mirror, failed_mirror);
7828                 return 0;
7829         }
7830
7831         return 1;
7832 }
7833
7834 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7835                         struct page *page, unsigned int pgoff,
7836                         u64 start, u64 end, int failed_mirror,
7837                         bio_end_io_t *repair_endio, void *repair_arg)
7838 {
7839         struct io_failure_record *failrec;
7840         struct bio *bio;
7841         int isector;
7842         int read_mode;
7843         int ret;
7844
7845         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7846
7847         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7848         if (ret)
7849                 return ret;
7850
7851         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7852                                          failed_mirror);
7853         if (!ret) {
7854                 free_io_failure(inode, failrec);
7855                 return -EIO;
7856         }
7857
7858         if ((failed_bio->bi_vcnt > 1)
7859                 || (failed_bio->bi_io_vec->bv_len
7860                         > BTRFS_I(inode)->root->sectorsize))
7861                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7862         else
7863                 read_mode = READ_SYNC;
7864
7865         isector = start - btrfs_io_bio(failed_bio)->logical;
7866         isector >>= inode->i_sb->s_blocksize_bits;
7867         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7868                                 pgoff, isector, repair_endio, repair_arg);
7869         if (!bio) {
7870                 free_io_failure(inode, failrec);
7871                 return -EIO;
7872         }
7873         bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
7874
7875         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7876                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7877                     read_mode, failrec->this_mirror, failrec->in_validation);
7878
7879         ret = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7880         if (ret) {
7881                 free_io_failure(inode, failrec);
7882                 bio_put(bio);
7883         }
7884
7885         return ret;
7886 }
7887
7888 struct btrfs_retry_complete {
7889         struct completion done;
7890         struct inode *inode;
7891         u64 start;
7892         int uptodate;
7893 };
7894
7895 static void btrfs_retry_endio_nocsum(struct bio *bio)
7896 {
7897         struct btrfs_retry_complete *done = bio->bi_private;
7898         struct inode *inode;
7899         struct bio_vec *bvec;
7900         int i;
7901
7902         if (bio->bi_error)
7903                 goto end;
7904
7905         ASSERT(bio->bi_vcnt == 1);
7906         inode = bio->bi_io_vec->bv_page->mapping->host;
7907         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
7908
7909         done->uptodate = 1;
7910         bio_for_each_segment_all(bvec, bio, i)
7911                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7912 end:
7913         complete(&done->done);
7914         bio_put(bio);
7915 }
7916
7917 static int __btrfs_correct_data_nocsum(struct inode *inode,
7918                                        struct btrfs_io_bio *io_bio)
7919 {
7920         struct btrfs_fs_info *fs_info;
7921         struct bio_vec *bvec;
7922         struct btrfs_retry_complete done;
7923         u64 start;
7924         unsigned int pgoff;
7925         u32 sectorsize;
7926         int nr_sectors;
7927         int i;
7928         int ret;
7929
7930         fs_info = BTRFS_I(inode)->root->fs_info;
7931         sectorsize = BTRFS_I(inode)->root->sectorsize;
7932
7933         start = io_bio->logical;
7934         done.inode = inode;
7935
7936         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7937                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
7938                 pgoff = bvec->bv_offset;
7939
7940 next_block_or_try_again:
7941                 done.uptodate = 0;
7942                 done.start = start;
7943                 init_completion(&done.done);
7944
7945                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
7946                                 pgoff, start, start + sectorsize - 1,
7947                                 io_bio->mirror_num,
7948                                 btrfs_retry_endio_nocsum, &done);
7949                 if (ret)
7950                         return ret;
7951
7952                 wait_for_completion(&done.done);
7953
7954                 if (!done.uptodate) {
7955                         /* We might have another mirror, so try again */
7956                         goto next_block_or_try_again;
7957                 }
7958
7959                 start += sectorsize;
7960
7961                 if (nr_sectors--) {
7962                         pgoff += sectorsize;
7963                         goto next_block_or_try_again;
7964                 }
7965         }
7966
7967         return 0;
7968 }
7969
7970 static void btrfs_retry_endio(struct bio *bio)
7971 {
7972         struct btrfs_retry_complete *done = bio->bi_private;
7973         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7974         struct inode *inode;
7975         struct bio_vec *bvec;
7976         u64 start;
7977         int uptodate;
7978         int ret;
7979         int i;
7980
7981         if (bio->bi_error)
7982                 goto end;
7983
7984         uptodate = 1;
7985
7986         start = done->start;
7987
7988         ASSERT(bio->bi_vcnt == 1);
7989         inode = bio->bi_io_vec->bv_page->mapping->host;
7990         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
7991
7992         bio_for_each_segment_all(bvec, bio, i) {
7993                 ret = __readpage_endio_check(done->inode, io_bio, i,
7994                                         bvec->bv_page, bvec->bv_offset,
7995                                         done->start, bvec->bv_len);
7996                 if (!ret)
7997                         clean_io_failure(done->inode, done->start,
7998                                         bvec->bv_page, bvec->bv_offset);
7999                 else
8000                         uptodate = 0;
8001         }
8002
8003         done->uptodate = uptodate;
8004 end:
8005         complete(&done->done);
8006         bio_put(bio);
8007 }
8008
8009 static int __btrfs_subio_endio_read(struct inode *inode,
8010                                     struct btrfs_io_bio *io_bio, int err)
8011 {
8012         struct btrfs_fs_info *fs_info;
8013         struct bio_vec *bvec;
8014         struct btrfs_retry_complete done;
8015         u64 start;
8016         u64 offset = 0;
8017         u32 sectorsize;
8018         int nr_sectors;
8019         unsigned int pgoff;
8020         int csum_pos;
8021         int i;
8022         int ret;
8023
8024         fs_info = BTRFS_I(inode)->root->fs_info;
8025         sectorsize = BTRFS_I(inode)->root->sectorsize;
8026
8027         err = 0;
8028         start = io_bio->logical;
8029         done.inode = inode;
8030
8031         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
8032                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8033
8034                 pgoff = bvec->bv_offset;
8035 next_block:
8036                 csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8037                 ret = __readpage_endio_check(inode, io_bio, csum_pos,
8038                                         bvec->bv_page, pgoff, start,
8039                                         sectorsize);
8040                 if (likely(!ret))
8041                         goto next;
8042 try_again:
8043                 done.uptodate = 0;
8044                 done.start = start;
8045                 init_completion(&done.done);
8046
8047                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8048                                 pgoff, start, start + sectorsize - 1,
8049                                 io_bio->mirror_num,
8050                                 btrfs_retry_endio, &done);
8051                 if (ret) {
8052                         err = ret;
8053                         goto next;
8054                 }
8055
8056                 wait_for_completion(&done.done);
8057
8058                 if (!done.uptodate) {
8059                         /* We might have another mirror, so try again */
8060                         goto try_again;
8061                 }
8062 next:
8063                 offset += sectorsize;
8064                 start += sectorsize;
8065
8066                 ASSERT(nr_sectors);
8067
8068                 if (--nr_sectors) {
8069                         pgoff += sectorsize;
8070                         goto next_block;
8071                 }
8072         }
8073
8074         return err;
8075 }
8076
8077 static int btrfs_subio_endio_read(struct inode *inode,
8078                                   struct btrfs_io_bio *io_bio, int err)
8079 {
8080         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8081
8082         if (skip_csum) {
8083                 if (unlikely(err))
8084                         return __btrfs_correct_data_nocsum(inode, io_bio);
8085                 else
8086                         return 0;
8087         } else {
8088                 return __btrfs_subio_endio_read(inode, io_bio, err);
8089         }
8090 }
8091
8092 static void btrfs_endio_direct_read(struct bio *bio)
8093 {
8094         struct btrfs_dio_private *dip = bio->bi_private;
8095         struct inode *inode = dip->inode;
8096         struct bio *dio_bio;
8097         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8098         int err = bio->bi_error;
8099
8100         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8101                 err = btrfs_subio_endio_read(inode, io_bio, err);
8102
8103         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8104                       dip->logical_offset + dip->bytes - 1);
8105         dio_bio = dip->dio_bio;
8106
8107         kfree(dip);
8108
8109         dio_bio->bi_error = bio->bi_error;
8110         dio_end_io(dio_bio, bio->bi_error);
8111
8112         if (io_bio->end_io)
8113                 io_bio->end_io(io_bio, err);
8114         bio_put(bio);
8115 }
8116
8117 static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
8118                                                     const u64 offset,
8119                                                     const u64 bytes,
8120                                                     const int uptodate)
8121 {
8122         struct btrfs_root *root = BTRFS_I(inode)->root;
8123         struct btrfs_ordered_extent *ordered = NULL;
8124         u64 ordered_offset = offset;
8125         u64 ordered_bytes = bytes;
8126         int ret;
8127
8128 again:
8129         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8130                                                    &ordered_offset,
8131                                                    ordered_bytes,
8132                                                    uptodate);
8133         if (!ret)
8134                 goto out_test;
8135
8136         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8137                         finish_ordered_fn, NULL, NULL);
8138         btrfs_queue_work(root->fs_info->endio_write_workers,
8139                          &ordered->work);
8140 out_test:
8141         /*
8142          * our bio might span multiple ordered extents.  If we haven't
8143          * completed the accounting for the whole dio, go back and try again
8144          */
8145         if (ordered_offset < offset + bytes) {
8146                 ordered_bytes = offset + bytes - ordered_offset;
8147                 ordered = NULL;
8148                 goto again;
8149         }
8150 }
8151
8152 static void btrfs_endio_direct_write(struct bio *bio)
8153 {
8154         struct btrfs_dio_private *dip = bio->bi_private;
8155         struct bio *dio_bio = dip->dio_bio;
8156
8157         btrfs_endio_direct_write_update_ordered(dip->inode,
8158                                                 dip->logical_offset,
8159                                                 dip->bytes,
8160                                                 !bio->bi_error);
8161
8162         kfree(dip);
8163
8164         dio_bio->bi_error = bio->bi_error;
8165         dio_end_io(dio_bio, bio->bi_error);
8166         bio_put(bio);
8167 }
8168
8169 static int __btrfs_submit_bio_start_direct_io(struct inode *inode,
8170                                     struct bio *bio, int mirror_num,
8171                                     unsigned long bio_flags, u64 offset)
8172 {
8173         int ret;
8174         struct btrfs_root *root = BTRFS_I(inode)->root;
8175         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
8176         BUG_ON(ret); /* -ENOMEM */
8177         return 0;
8178 }
8179
8180 static void btrfs_end_dio_bio(struct bio *bio)
8181 {
8182         struct btrfs_dio_private *dip = bio->bi_private;
8183         int err = bio->bi_error;
8184
8185         if (err)
8186                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8187                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8188                            btrfs_ino(dip->inode), bio_op(bio), bio->bi_rw,
8189                            (unsigned long long)bio->bi_iter.bi_sector,
8190                            bio->bi_iter.bi_size, err);
8191
8192         if (dip->subio_endio)
8193                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8194
8195         if (err) {
8196                 dip->errors = 1;
8197
8198                 /*
8199                  * before atomic variable goto zero, we must make sure
8200                  * dip->errors is perceived to be set.
8201                  */
8202                 smp_mb__before_atomic();
8203         }
8204
8205         /* if there are more bios still pending for this dio, just exit */
8206         if (!atomic_dec_and_test(&dip->pending_bios))
8207                 goto out;
8208
8209         if (dip->errors) {
8210                 bio_io_error(dip->orig_bio);
8211         } else {
8212                 dip->dio_bio->bi_error = 0;
8213                 bio_endio(dip->orig_bio);
8214         }
8215 out:
8216         bio_put(bio);
8217 }
8218
8219 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8220                                        u64 first_sector, gfp_t gfp_flags)
8221 {
8222         struct bio *bio;
8223         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8224         if (bio)
8225                 bio_associate_current(bio);
8226         return bio;
8227 }
8228
8229 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
8230                                                  struct inode *inode,
8231                                                  struct btrfs_dio_private *dip,
8232                                                  struct bio *bio,
8233                                                  u64 file_offset)
8234 {
8235         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8236         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8237         int ret;
8238
8239         /*
8240          * We load all the csum data we need when we submit
8241          * the first bio to reduce the csum tree search and
8242          * contention.
8243          */
8244         if (dip->logical_offset == file_offset) {
8245                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
8246                                                 file_offset);
8247                 if (ret)
8248                         return ret;
8249         }
8250
8251         if (bio == dip->orig_bio)
8252                 return 0;
8253
8254         file_offset -= dip->logical_offset;
8255         file_offset >>= inode->i_sb->s_blocksize_bits;
8256         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8257
8258         return 0;
8259 }
8260
8261 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8262                                          u64 file_offset, int skip_sum,
8263                                          int async_submit)
8264 {
8265         struct btrfs_dio_private *dip = bio->bi_private;
8266         bool write = bio_op(bio) == REQ_OP_WRITE;
8267         struct btrfs_root *root = BTRFS_I(inode)->root;
8268         int ret;
8269
8270         if (async_submit)
8271                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8272
8273         bio_get(bio);
8274
8275         if (!write) {
8276                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
8277                                 BTRFS_WQ_ENDIO_DATA);
8278                 if (ret)
8279                         goto err;
8280         }
8281
8282         if (skip_sum)
8283                 goto map;
8284
8285         if (write && async_submit) {
8286                 ret = btrfs_wq_submit_bio(root->fs_info,
8287                                    inode, bio, 0, 0, file_offset,
8288                                    __btrfs_submit_bio_start_direct_io,
8289                                    __btrfs_submit_bio_done);
8290                 goto err;
8291         } else if (write) {
8292                 /*
8293                  * If we aren't doing async submit, calculate the csum of the
8294                  * bio now.
8295                  */
8296                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
8297                 if (ret)
8298                         goto err;
8299         } else {
8300                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
8301                                                      file_offset);
8302                 if (ret)
8303                         goto err;
8304         }
8305 map:
8306         ret = btrfs_map_bio(root, bio, 0, async_submit);
8307 err:
8308         bio_put(bio);
8309         return ret;
8310 }
8311
8312 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
8313                                     int skip_sum)
8314 {
8315         struct inode *inode = dip->inode;
8316         struct btrfs_root *root = BTRFS_I(inode)->root;
8317         struct bio *bio;
8318         struct bio *orig_bio = dip->orig_bio;
8319         struct bio_vec *bvec = orig_bio->bi_io_vec;
8320         u64 start_sector = orig_bio->bi_iter.bi_sector;
8321         u64 file_offset = dip->logical_offset;
8322         u64 submit_len = 0;
8323         u64 map_length;
8324         u32 blocksize = root->sectorsize;
8325         int async_submit = 0;
8326         int nr_sectors;
8327         int ret;
8328         int i;
8329
8330         map_length = orig_bio->bi_iter.bi_size;
8331         ret = btrfs_map_block(root->fs_info, bio_op(orig_bio),
8332                               start_sector << 9, &map_length, NULL, 0);
8333         if (ret)
8334                 return -EIO;
8335
8336         if (map_length >= orig_bio->bi_iter.bi_size) {
8337                 bio = orig_bio;
8338                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8339                 goto submit;
8340         }
8341
8342         /* async crcs make it difficult to collect full stripe writes. */
8343         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8344                 async_submit = 0;
8345         else
8346                 async_submit = 1;
8347
8348         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8349         if (!bio)
8350                 return -ENOMEM;
8351
8352         bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
8353         bio->bi_private = dip;
8354         bio->bi_end_io = btrfs_end_dio_bio;
8355         btrfs_io_bio(bio)->logical = file_offset;
8356         atomic_inc(&dip->pending_bios);
8357
8358         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
8359                 nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len);
8360                 i = 0;
8361 next_block:
8362                 if (unlikely(map_length < submit_len + blocksize ||
8363                     bio_add_page(bio, bvec->bv_page, blocksize,
8364                             bvec->bv_offset + (i * blocksize)) < blocksize)) {
8365                         /*
8366                          * inc the count before we submit the bio so
8367                          * we know the end IO handler won't happen before
8368                          * we inc the count. Otherwise, the dip might get freed
8369                          * before we're done setting it up
8370                          */
8371                         atomic_inc(&dip->pending_bios);
8372                         ret = __btrfs_submit_dio_bio(bio, inode,
8373                                                      file_offset, skip_sum,
8374                                                      async_submit);
8375                         if (ret) {
8376                                 bio_put(bio);
8377                                 atomic_dec(&dip->pending_bios);
8378                                 goto out_err;
8379                         }
8380
8381                         start_sector += submit_len >> 9;
8382                         file_offset += submit_len;
8383
8384                         submit_len = 0;
8385
8386                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8387                                                   start_sector, GFP_NOFS);
8388                         if (!bio)
8389                                 goto out_err;
8390                         bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
8391                         bio->bi_private = dip;
8392                         bio->bi_end_io = btrfs_end_dio_bio;
8393                         btrfs_io_bio(bio)->logical = file_offset;
8394
8395                         map_length = orig_bio->bi_iter.bi_size;
8396                         ret = btrfs_map_block(root->fs_info, bio_op(orig_bio),
8397                                               start_sector << 9,
8398                                               &map_length, NULL, 0);
8399                         if (ret) {
8400                                 bio_put(bio);
8401                                 goto out_err;
8402                         }
8403
8404                         goto next_block;
8405                 } else {
8406                         submit_len += blocksize;
8407                         if (--nr_sectors) {
8408                                 i++;
8409                                 goto next_block;
8410                         }
8411                         bvec++;
8412                 }
8413         }
8414
8415 submit:
8416         ret = __btrfs_submit_dio_bio(bio, inode, file_offset, skip_sum,
8417                                      async_submit);
8418         if (!ret)
8419                 return 0;
8420
8421         bio_put(bio);
8422 out_err:
8423         dip->errors = 1;
8424         /*
8425          * before atomic variable goto zero, we must
8426          * make sure dip->errors is perceived to be set.
8427          */
8428         smp_mb__before_atomic();
8429         if (atomic_dec_and_test(&dip->pending_bios))
8430                 bio_io_error(dip->orig_bio);
8431
8432         /* bio_end_io() will handle error, so we needn't return it */
8433         return 0;
8434 }
8435
8436 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8437                                 loff_t file_offset)
8438 {
8439         struct btrfs_dio_private *dip = NULL;
8440         struct bio *io_bio = NULL;
8441         struct btrfs_io_bio *btrfs_bio;
8442         int skip_sum;
8443         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8444         int ret = 0;
8445
8446         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8447
8448         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8449         if (!io_bio) {
8450                 ret = -ENOMEM;
8451                 goto free_ordered;
8452         }
8453
8454         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8455         if (!dip) {
8456                 ret = -ENOMEM;
8457                 goto free_ordered;
8458         }
8459
8460         dip->private = dio_bio->bi_private;
8461         dip->inode = inode;
8462         dip->logical_offset = file_offset;
8463         dip->bytes = dio_bio->bi_iter.bi_size;
8464         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8465         io_bio->bi_private = dip;
8466         dip->orig_bio = io_bio;
8467         dip->dio_bio = dio_bio;
8468         atomic_set(&dip->pending_bios, 0);
8469         btrfs_bio = btrfs_io_bio(io_bio);
8470         btrfs_bio->logical = file_offset;
8471
8472         if (write) {
8473                 io_bio->bi_end_io = btrfs_endio_direct_write;
8474         } else {
8475                 io_bio->bi_end_io = btrfs_endio_direct_read;
8476                 dip->subio_endio = btrfs_subio_endio_read;
8477         }
8478
8479         /*
8480          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8481          * even if we fail to submit a bio, because in such case we do the
8482          * corresponding error handling below and it must not be done a second
8483          * time by btrfs_direct_IO().
8484          */
8485         if (write) {
8486                 struct btrfs_dio_data *dio_data = current->journal_info;
8487
8488                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8489                         dip->bytes;
8490                 dio_data->unsubmitted_oe_range_start =
8491                         dio_data->unsubmitted_oe_range_end;
8492         }
8493
8494         ret = btrfs_submit_direct_hook(dip, skip_sum);
8495         if (!ret)
8496                 return;
8497
8498         if (btrfs_bio->end_io)
8499                 btrfs_bio->end_io(btrfs_bio, ret);
8500
8501 free_ordered:
8502         /*
8503          * If we arrived here it means either we failed to submit the dip
8504          * or we either failed to clone the dio_bio or failed to allocate the
8505          * dip. If we cloned the dio_bio and allocated the dip, we can just
8506          * call bio_endio against our io_bio so that we get proper resource
8507          * cleanup if we fail to submit the dip, otherwise, we must do the
8508          * same as btrfs_endio_direct_[write|read] because we can't call these
8509          * callbacks - they require an allocated dip and a clone of dio_bio.
8510          */
8511         if (io_bio && dip) {
8512                 io_bio->bi_error = -EIO;
8513                 bio_endio(io_bio);
8514                 /*
8515                  * The end io callbacks free our dip, do the final put on io_bio
8516                  * and all the cleanup and final put for dio_bio (through
8517                  * dio_end_io()).
8518                  */
8519                 dip = NULL;
8520                 io_bio = NULL;
8521         } else {
8522                 if (write)
8523                         btrfs_endio_direct_write_update_ordered(inode,
8524                                                 file_offset,
8525                                                 dio_bio->bi_iter.bi_size,
8526                                                 0);
8527                 else
8528                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8529                               file_offset + dio_bio->bi_iter.bi_size - 1);
8530
8531                 dio_bio->bi_error = -EIO;
8532                 /*
8533                  * Releases and cleans up our dio_bio, no need to bio_put()
8534                  * nor bio_endio()/bio_io_error() against dio_bio.
8535                  */
8536                 dio_end_io(dio_bio, ret);
8537         }
8538         if (io_bio)
8539                 bio_put(io_bio);
8540         kfree(dip);
8541 }
8542
8543 static ssize_t check_direct_IO(struct btrfs_root *root, struct kiocb *iocb,
8544                         const struct iov_iter *iter, loff_t offset)
8545 {
8546         int seg;
8547         int i;
8548         unsigned blocksize_mask = root->sectorsize - 1;
8549         ssize_t retval = -EINVAL;
8550
8551         if (offset & blocksize_mask)
8552                 goto out;
8553
8554         if (iov_iter_alignment(iter) & blocksize_mask)
8555                 goto out;
8556
8557         /* If this is a write we don't need to check anymore */
8558         if (iov_iter_rw(iter) == WRITE)
8559                 return 0;
8560         /*
8561          * Check to make sure we don't have duplicate iov_base's in this
8562          * iovec, if so return EINVAL, otherwise we'll get csum errors
8563          * when reading back.
8564          */
8565         for (seg = 0; seg < iter->nr_segs; seg++) {
8566                 for (i = seg + 1; i < iter->nr_segs; i++) {
8567                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8568                                 goto out;
8569                 }
8570         }
8571         retval = 0;
8572 out:
8573         return retval;
8574 }
8575
8576 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8577 {
8578         struct file *file = iocb->ki_filp;
8579         struct inode *inode = file->f_mapping->host;
8580         struct btrfs_root *root = BTRFS_I(inode)->root;
8581         struct btrfs_dio_data dio_data = { 0 };
8582         loff_t offset = iocb->ki_pos;
8583         size_t count = 0;
8584         int flags = 0;
8585         bool wakeup = true;
8586         bool relock = false;
8587         ssize_t ret;
8588
8589         if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
8590                 return 0;
8591
8592         inode_dio_begin(inode);
8593         smp_mb__after_atomic();
8594
8595         /*
8596          * The generic stuff only does filemap_write_and_wait_range, which
8597          * isn't enough if we've written compressed pages to this area, so
8598          * we need to flush the dirty pages again to make absolutely sure
8599          * that any outstanding dirty pages are on disk.
8600          */
8601         count = iov_iter_count(iter);
8602         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8603                      &BTRFS_I(inode)->runtime_flags))
8604                 filemap_fdatawrite_range(inode->i_mapping, offset,
8605                                          offset + count - 1);
8606
8607         if (iov_iter_rw(iter) == WRITE) {
8608                 /*
8609                  * If the write DIO is beyond the EOF, we need update
8610                  * the isize, but it is protected by i_mutex. So we can
8611                  * not unlock the i_mutex at this case.
8612                  */
8613                 if (offset + count <= inode->i_size) {
8614                         inode_unlock(inode);
8615                         relock = true;
8616                 }
8617                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8618                 if (ret)
8619                         goto out;
8620                 dio_data.outstanding_extents = div64_u64(count +
8621                                                 BTRFS_MAX_EXTENT_SIZE - 1,
8622                                                 BTRFS_MAX_EXTENT_SIZE);
8623
8624                 /*
8625                  * We need to know how many extents we reserved so that we can
8626                  * do the accounting properly if we go over the number we
8627                  * originally calculated.  Abuse current->journal_info for this.
8628                  */
8629                 dio_data.reserve = round_up(count, root->sectorsize);
8630                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8631                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8632                 current->journal_info = &dio_data;
8633         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8634                                      &BTRFS_I(inode)->runtime_flags)) {
8635                 inode_dio_end(inode);
8636                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8637                 wakeup = false;
8638         }
8639
8640         ret = __blockdev_direct_IO(iocb, inode,
8641                                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8642                                    iter, btrfs_get_blocks_direct, NULL,
8643                                    btrfs_submit_direct, flags);
8644         if (iov_iter_rw(iter) == WRITE) {
8645                 current->journal_info = NULL;
8646                 if (ret < 0 && ret != -EIOCBQUEUED) {
8647                         if (dio_data.reserve)
8648                                 btrfs_delalloc_release_space(inode, offset,
8649                                                              dio_data.reserve);
8650                         /*
8651                          * On error we might have left some ordered extents
8652                          * without submitting corresponding bios for them, so
8653                          * cleanup them up to avoid other tasks getting them
8654                          * and waiting for them to complete forever.
8655                          */
8656                         if (dio_data.unsubmitted_oe_range_start <
8657                             dio_data.unsubmitted_oe_range_end)
8658                                 btrfs_endio_direct_write_update_ordered(inode,
8659                                         dio_data.unsubmitted_oe_range_start,
8660                                         dio_data.unsubmitted_oe_range_end -
8661                                         dio_data.unsubmitted_oe_range_start,
8662                                         0);
8663                 } else if (ret >= 0 && (size_t)ret < count)
8664                         btrfs_delalloc_release_space(inode, offset,
8665                                                      count - (size_t)ret);
8666         }
8667 out:
8668         if (wakeup)
8669                 inode_dio_end(inode);
8670         if (relock)
8671                 inode_lock(inode);
8672
8673         return ret;
8674 }
8675
8676 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8677
8678 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8679                 __u64 start, __u64 len)
8680 {
8681         int     ret;
8682
8683         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8684         if (ret)
8685                 return ret;
8686
8687         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8688 }
8689
8690 int btrfs_readpage(struct file *file, struct page *page)
8691 {
8692         struct extent_io_tree *tree;
8693         tree = &BTRFS_I(page->mapping->host)->io_tree;
8694         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8695 }
8696
8697 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8698 {
8699         struct extent_io_tree *tree;
8700         struct inode *inode = page->mapping->host;
8701         int ret;
8702
8703         if (current->flags & PF_MEMALLOC) {
8704                 redirty_page_for_writepage(wbc, page);
8705                 unlock_page(page);
8706                 return 0;
8707         }
8708
8709         /*
8710          * If we are under memory pressure we will call this directly from the
8711          * VM, we need to make sure we have the inode referenced for the ordered
8712          * extent.  If not just return like we didn't do anything.
8713          */
8714         if (!igrab(inode)) {
8715                 redirty_page_for_writepage(wbc, page);
8716                 return AOP_WRITEPAGE_ACTIVATE;
8717         }
8718         tree = &BTRFS_I(page->mapping->host)->io_tree;
8719         ret = extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8720         btrfs_add_delayed_iput(inode);
8721         return ret;
8722 }
8723
8724 static int btrfs_writepages(struct address_space *mapping,
8725                             struct writeback_control *wbc)
8726 {
8727         struct extent_io_tree *tree;
8728
8729         tree = &BTRFS_I(mapping->host)->io_tree;
8730         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8731 }
8732
8733 static int
8734 btrfs_readpages(struct file *file, struct address_space *mapping,
8735                 struct list_head *pages, unsigned nr_pages)
8736 {
8737         struct extent_io_tree *tree;
8738         tree = &BTRFS_I(mapping->host)->io_tree;
8739         return extent_readpages(tree, mapping, pages, nr_pages,
8740                                 btrfs_get_extent);
8741 }
8742 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8743 {
8744         struct extent_io_tree *tree;
8745         struct extent_map_tree *map;
8746         int ret;
8747
8748         tree = &BTRFS_I(page->mapping->host)->io_tree;
8749         map = &BTRFS_I(page->mapping->host)->extent_tree;
8750         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8751         if (ret == 1) {
8752                 ClearPagePrivate(page);
8753                 set_page_private(page, 0);
8754                 put_page(page);
8755         }
8756         return ret;
8757 }
8758
8759 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8760 {
8761         if (PageWriteback(page) || PageDirty(page))
8762                 return 0;
8763         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8764 }
8765
8766 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8767                                  unsigned int length)
8768 {
8769         struct inode *inode = page->mapping->host;
8770         struct extent_io_tree *tree;
8771         struct btrfs_ordered_extent *ordered;
8772         struct extent_state *cached_state = NULL;
8773         u64 page_start = page_offset(page);
8774         u64 page_end = page_start + PAGE_SIZE - 1;
8775         u64 start;
8776         u64 end;
8777         int inode_evicting = inode->i_state & I_FREEING;
8778
8779         /*
8780          * we have the page locked, so new writeback can't start,
8781          * and the dirty bit won't be cleared while we are here.
8782          *
8783          * Wait for IO on this page so that we can safely clear
8784          * the PagePrivate2 bit and do ordered accounting
8785          */
8786         wait_on_page_writeback(page);
8787
8788         tree = &BTRFS_I(inode)->io_tree;
8789         if (offset) {
8790                 btrfs_releasepage(page, GFP_NOFS);
8791                 return;
8792         }
8793
8794         if (!inode_evicting)
8795                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8796 again:
8797         start = page_start;
8798         ordered = btrfs_lookup_ordered_range(inode, start,
8799                                         page_end - start + 1);
8800         if (ordered) {
8801                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8802                 /*
8803                  * IO on this page will never be started, so we need
8804                  * to account for any ordered extents now
8805                  */
8806                 if (!inode_evicting)
8807                         clear_extent_bit(tree, start, end,
8808                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8809                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8810                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8811                                          GFP_NOFS);
8812                 /*
8813                  * whoever cleared the private bit is responsible
8814                  * for the finish_ordered_io
8815                  */
8816                 if (TestClearPagePrivate2(page)) {
8817                         struct btrfs_ordered_inode_tree *tree;
8818                         u64 new_len;
8819
8820                         tree = &BTRFS_I(inode)->ordered_tree;
8821
8822                         spin_lock_irq(&tree->lock);
8823                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8824                         new_len = start - ordered->file_offset;
8825                         if (new_len < ordered->truncated_len)
8826                                 ordered->truncated_len = new_len;
8827                         spin_unlock_irq(&tree->lock);
8828
8829                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8830                                                            start,
8831                                                            end - start + 1, 1))
8832                                 btrfs_finish_ordered_io(ordered);
8833                 }
8834                 btrfs_put_ordered_extent(ordered);
8835                 if (!inode_evicting) {
8836                         cached_state = NULL;
8837                         lock_extent_bits(tree, start, end,
8838                                          &cached_state);
8839                 }
8840
8841                 start = end + 1;
8842                 if (start < page_end)
8843                         goto again;
8844         }
8845
8846         /*
8847          * Qgroup reserved space handler
8848          * Page here will be either
8849          * 1) Already written to disk
8850          *    In this case, its reserved space is released from data rsv map
8851          *    and will be freed by delayed_ref handler finally.
8852          *    So even we call qgroup_free_data(), it won't decrease reserved
8853          *    space.
8854          * 2) Not written to disk
8855          *    This means the reserved space should be freed here.
8856          */
8857         btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE);
8858         if (!inode_evicting) {
8859                 clear_extent_bit(tree, page_start, page_end,
8860                                  EXTENT_LOCKED | EXTENT_DIRTY |
8861                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8862                                  EXTENT_DEFRAG, 1, 1,
8863                                  &cached_state, GFP_NOFS);
8864
8865                 __btrfs_releasepage(page, GFP_NOFS);
8866         }
8867
8868         ClearPageChecked(page);
8869         if (PagePrivate(page)) {
8870                 ClearPagePrivate(page);
8871                 set_page_private(page, 0);
8872                 put_page(page);
8873         }
8874 }
8875
8876 /*
8877  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8878  * called from a page fault handler when a page is first dirtied. Hence we must
8879  * be careful to check for EOF conditions here. We set the page up correctly
8880  * for a written page which means we get ENOSPC checking when writing into
8881  * holes and correct delalloc and unwritten extent mapping on filesystems that
8882  * support these features.
8883  *
8884  * We are not allowed to take the i_mutex here so we have to play games to
8885  * protect against truncate races as the page could now be beyond EOF.  Because
8886  * vmtruncate() writes the inode size before removing pages, once we have the
8887  * page lock we can determine safely if the page is beyond EOF. If it is not
8888  * beyond EOF, then the page is guaranteed safe against truncation until we
8889  * unlock the page.
8890  */
8891 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8892 {
8893         struct page *page = vmf->page;
8894         struct inode *inode = file_inode(vma->vm_file);
8895         struct btrfs_root *root = BTRFS_I(inode)->root;
8896         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8897         struct btrfs_ordered_extent *ordered;
8898         struct extent_state *cached_state = NULL;
8899         char *kaddr;
8900         unsigned long zero_start;
8901         loff_t size;
8902         int ret;
8903         int reserved = 0;
8904         u64 reserved_space;
8905         u64 page_start;
8906         u64 page_end;
8907         u64 end;
8908
8909         reserved_space = PAGE_SIZE;
8910
8911         sb_start_pagefault(inode->i_sb);
8912         page_start = page_offset(page);
8913         page_end = page_start + PAGE_SIZE - 1;
8914         end = page_end;
8915
8916         /*
8917          * Reserving delalloc space after obtaining the page lock can lead to
8918          * deadlock. For example, if a dirty page is locked by this function
8919          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8920          * dirty page write out, then the btrfs_writepage() function could
8921          * end up waiting indefinitely to get a lock on the page currently
8922          * being processed by btrfs_page_mkwrite() function.
8923          */
8924         ret = btrfs_delalloc_reserve_space(inode, page_start,
8925                                            reserved_space);
8926         if (!ret) {
8927                 ret = file_update_time(vma->vm_file);
8928                 reserved = 1;
8929         }
8930         if (ret) {
8931                 if (ret == -ENOMEM)
8932                         ret = VM_FAULT_OOM;
8933                 else /* -ENOSPC, -EIO, etc */
8934                         ret = VM_FAULT_SIGBUS;
8935                 if (reserved)
8936                         goto out;
8937                 goto out_noreserve;
8938         }
8939
8940         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8941 again:
8942         lock_page(page);
8943         size = i_size_read(inode);
8944
8945         if ((page->mapping != inode->i_mapping) ||
8946             (page_start >= size)) {
8947                 /* page got truncated out from underneath us */
8948                 goto out_unlock;
8949         }
8950         wait_on_page_writeback(page);
8951
8952         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8953         set_page_extent_mapped(page);
8954
8955         /*
8956          * we can't set the delalloc bits if there are pending ordered
8957          * extents.  Drop our locks and wait for them to finish
8958          */
8959         ordered = btrfs_lookup_ordered_range(inode, page_start, page_end);
8960         if (ordered) {
8961                 unlock_extent_cached(io_tree, page_start, page_end,
8962                                      &cached_state, GFP_NOFS);
8963                 unlock_page(page);
8964                 btrfs_start_ordered_extent(inode, ordered, 1);
8965                 btrfs_put_ordered_extent(ordered);
8966                 goto again;
8967         }
8968
8969         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8970                 reserved_space = round_up(size - page_start, root->sectorsize);
8971                 if (reserved_space < PAGE_SIZE) {
8972                         end = page_start + reserved_space - 1;
8973                         spin_lock(&BTRFS_I(inode)->lock);
8974                         BTRFS_I(inode)->outstanding_extents++;
8975                         spin_unlock(&BTRFS_I(inode)->lock);
8976                         btrfs_delalloc_release_space(inode, page_start,
8977                                                 PAGE_SIZE - reserved_space);
8978                 }
8979         }
8980
8981         /*
8982          * XXX - page_mkwrite gets called every time the page is dirtied, even
8983          * if it was already dirty, so for space accounting reasons we need to
8984          * clear any delalloc bits for the range we are fixing to save.  There
8985          * is probably a better way to do this, but for now keep consistent with
8986          * prepare_pages in the normal write path.
8987          */
8988         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8989                           EXTENT_DIRTY | EXTENT_DELALLOC |
8990                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8991                           0, 0, &cached_state, GFP_NOFS);
8992
8993         ret = btrfs_set_extent_delalloc(inode, page_start, end,
8994                                         &cached_state);
8995         if (ret) {
8996                 unlock_extent_cached(io_tree, page_start, page_end,
8997                                      &cached_state, GFP_NOFS);
8998                 ret = VM_FAULT_SIGBUS;
8999                 goto out_unlock;
9000         }
9001         ret = 0;
9002
9003         /* page is wholly or partially inside EOF */
9004         if (page_start + PAGE_SIZE > size)
9005                 zero_start = size & ~PAGE_MASK;
9006         else
9007                 zero_start = PAGE_SIZE;
9008
9009         if (zero_start != PAGE_SIZE) {
9010                 kaddr = kmap(page);
9011                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
9012                 flush_dcache_page(page);
9013                 kunmap(page);
9014         }
9015         ClearPageChecked(page);
9016         set_page_dirty(page);
9017         SetPageUptodate(page);
9018
9019         BTRFS_I(inode)->last_trans = root->fs_info->generation;
9020         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
9021         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
9022
9023         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
9024
9025 out_unlock:
9026         if (!ret) {
9027                 sb_end_pagefault(inode->i_sb);
9028                 return VM_FAULT_LOCKED;
9029         }
9030         unlock_page(page);
9031 out:
9032         btrfs_delalloc_release_space(inode, page_start, reserved_space);
9033 out_noreserve:
9034         sb_end_pagefault(inode->i_sb);
9035         return ret;
9036 }
9037
9038 static int btrfs_truncate(struct inode *inode)
9039 {
9040         struct btrfs_root *root = BTRFS_I(inode)->root;
9041         struct btrfs_block_rsv *rsv;
9042         int ret = 0;
9043         int err = 0;
9044         struct btrfs_trans_handle *trans;
9045         u64 mask = root->sectorsize - 1;
9046         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
9047
9048         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9049                                        (u64)-1);
9050         if (ret)
9051                 return ret;
9052
9053         /*
9054          * Yes ladies and gentlemen, this is indeed ugly.  The fact is we have
9055          * 3 things going on here
9056          *
9057          * 1) We need to reserve space for our orphan item and the space to
9058          * delete our orphan item.  Lord knows we don't want to have a dangling
9059          * orphan item because we didn't reserve space to remove it.
9060          *
9061          * 2) We need to reserve space to update our inode.
9062          *
9063          * 3) We need to have something to cache all the space that is going to
9064          * be free'd up by the truncate operation, but also have some slack
9065          * space reserved in case it uses space during the truncate (thank you
9066          * very much snapshotting).
9067          *
9068          * And we need these to all be separate.  The fact is we can use a lot of
9069          * space doing the truncate, and we have no earthly idea how much space
9070          * we will use, so we need the truncate reservation to be separate so it
9071          * doesn't end up using space reserved for updating the inode or
9072          * removing the orphan item.  We also need to be able to stop the
9073          * transaction and start a new one, which means we need to be able to
9074          * update the inode several times, and we have no idea of knowing how
9075          * many times that will be, so we can't just reserve 1 item for the
9076          * entirety of the operation, so that has to be done separately as well.
9077          * Then there is the orphan item, which does indeed need to be held on
9078          * to for the whole operation, and we need nobody to touch this reserved
9079          * space except the orphan code.
9080          *
9081          * So that leaves us with
9082          *
9083          * 1) root->orphan_block_rsv - for the orphan deletion.
9084          * 2) rsv - for the truncate reservation, which we will steal from the
9085          * transaction reservation.
9086          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
9087          * updating the inode.
9088          */
9089         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
9090         if (!rsv)
9091                 return -ENOMEM;
9092         rsv->size = min_size;
9093         rsv->failfast = 1;
9094
9095         /*
9096          * 1 for the truncate slack space
9097          * 1 for updating the inode.
9098          */
9099         trans = btrfs_start_transaction(root, 2);
9100         if (IS_ERR(trans)) {
9101                 err = PTR_ERR(trans);
9102                 goto out;
9103         }
9104
9105         /* Migrate the slack space for the truncate to our reserve */
9106         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
9107                                       min_size);
9108         BUG_ON(ret);
9109
9110         /*
9111          * So if we truncate and then write and fsync we normally would just
9112          * write the extents that changed, which is a problem if we need to
9113          * first truncate that entire inode.  So set this flag so we write out
9114          * all of the extents in the inode to the sync log so we're completely
9115          * safe.
9116          */
9117         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9118         trans->block_rsv = rsv;
9119
9120         while (1) {
9121                 ret = btrfs_truncate_inode_items(trans, root, inode,
9122                                                  inode->i_size,
9123                                                  BTRFS_EXTENT_DATA_KEY);
9124                 if (ret != -ENOSPC && ret != -EAGAIN) {
9125                         err = ret;
9126                         break;
9127                 }
9128
9129                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9130                 ret = btrfs_update_inode(trans, root, inode);
9131                 if (ret) {
9132                         err = ret;
9133                         break;
9134                 }
9135
9136                 btrfs_end_transaction(trans, root);
9137                 btrfs_btree_balance_dirty(root);
9138
9139                 trans = btrfs_start_transaction(root, 2);
9140                 if (IS_ERR(trans)) {
9141                         ret = err = PTR_ERR(trans);
9142                         trans = NULL;
9143                         break;
9144                 }
9145
9146                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
9147                                               rsv, min_size);
9148                 BUG_ON(ret);    /* shouldn't happen */
9149                 trans->block_rsv = rsv;
9150         }
9151
9152         if (ret == 0 && inode->i_nlink > 0) {
9153                 trans->block_rsv = root->orphan_block_rsv;
9154                 ret = btrfs_orphan_del(trans, inode);
9155                 if (ret)
9156                         err = ret;
9157         }
9158
9159         if (trans) {
9160                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9161                 ret = btrfs_update_inode(trans, root, inode);
9162                 if (ret && !err)
9163                         err = ret;
9164
9165                 ret = btrfs_end_transaction(trans, root);
9166                 btrfs_btree_balance_dirty(root);
9167         }
9168
9169 out:
9170         btrfs_free_block_rsv(root, rsv);
9171
9172         if (ret && !err)
9173                 err = ret;
9174
9175         return err;
9176 }
9177
9178 /*
9179  * create a new subvolume directory/inode (helper for the ioctl).
9180  */
9181 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9182                              struct btrfs_root *new_root,
9183                              struct btrfs_root *parent_root,
9184                              u64 new_dirid)
9185 {
9186         struct inode *inode;
9187         int err;
9188         u64 index = 0;
9189
9190         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9191                                 new_dirid, new_dirid,
9192                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9193                                 &index);
9194         if (IS_ERR(inode))
9195                 return PTR_ERR(inode);
9196         inode->i_op = &btrfs_dir_inode_operations;
9197         inode->i_fop = &btrfs_dir_file_operations;
9198
9199         set_nlink(inode, 1);
9200         btrfs_i_size_write(inode, 0);
9201         unlock_new_inode(inode);
9202
9203         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9204         if (err)
9205                 btrfs_err(new_root->fs_info,
9206                           "error inheriting subvolume %llu properties: %d",
9207                           new_root->root_key.objectid, err);
9208
9209         err = btrfs_update_inode(trans, new_root, inode);
9210
9211         iput(inode);
9212         return err;
9213 }
9214
9215 struct inode *btrfs_alloc_inode(struct super_block *sb)
9216 {
9217         struct btrfs_inode *ei;
9218         struct inode *inode;
9219
9220         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9221         if (!ei)
9222                 return NULL;
9223
9224         ei->root = NULL;
9225         ei->generation = 0;
9226         ei->last_trans = 0;
9227         ei->last_sub_trans = 0;
9228         ei->logged_trans = 0;
9229         ei->delalloc_bytes = 0;
9230         ei->defrag_bytes = 0;
9231         ei->disk_i_size = 0;
9232         ei->flags = 0;
9233         ei->csum_bytes = 0;
9234         ei->index_cnt = (u64)-1;
9235         ei->dir_index = 0;
9236         ei->last_unlink_trans = 0;
9237         ei->last_log_commit = 0;
9238         ei->delayed_iput_count = 0;
9239
9240         spin_lock_init(&ei->lock);
9241         ei->outstanding_extents = 0;
9242         ei->reserved_extents = 0;
9243
9244         ei->runtime_flags = 0;
9245         ei->force_compress = BTRFS_COMPRESS_NONE;
9246
9247         ei->delayed_node = NULL;
9248
9249         ei->i_otime.tv_sec = 0;
9250         ei->i_otime.tv_nsec = 0;
9251
9252         inode = &ei->vfs_inode;
9253         extent_map_tree_init(&ei->extent_tree);
9254         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9255         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9256         ei->io_tree.track_uptodate = 1;
9257         ei->io_failure_tree.track_uptodate = 1;
9258         atomic_set(&ei->sync_writers, 0);
9259         mutex_init(&ei->log_mutex);
9260         mutex_init(&ei->delalloc_mutex);
9261         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9262         INIT_LIST_HEAD(&ei->delalloc_inodes);
9263         INIT_LIST_HEAD(&ei->delayed_iput);
9264         RB_CLEAR_NODE(&ei->rb_node);
9265         init_rwsem(&ei->dio_sem);
9266
9267         return inode;
9268 }
9269
9270 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9271 void btrfs_test_destroy_inode(struct inode *inode)
9272 {
9273         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9274         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9275 }
9276 #endif
9277
9278 static void btrfs_i_callback(struct rcu_head *head)
9279 {
9280         struct inode *inode = container_of(head, struct inode, i_rcu);
9281         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9282 }
9283
9284 void btrfs_destroy_inode(struct inode *inode)
9285 {
9286         struct btrfs_ordered_extent *ordered;
9287         struct btrfs_root *root = BTRFS_I(inode)->root;
9288
9289         WARN_ON(!hlist_empty(&inode->i_dentry));
9290         WARN_ON(inode->i_data.nrpages);
9291         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9292         WARN_ON(BTRFS_I(inode)->reserved_extents);
9293         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9294         WARN_ON(BTRFS_I(inode)->csum_bytes);
9295         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9296
9297         /*
9298          * This can happen where we create an inode, but somebody else also
9299          * created the same inode and we need to destroy the one we already
9300          * created.
9301          */
9302         if (!root)
9303                 goto free;
9304
9305         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9306                      &BTRFS_I(inode)->runtime_flags)) {
9307                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
9308                         btrfs_ino(inode));
9309                 atomic_dec(&root->orphan_inodes);
9310         }
9311
9312         while (1) {
9313                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9314                 if (!ordered)
9315                         break;
9316                 else {
9317                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
9318                                 ordered->file_offset, ordered->len);
9319                         btrfs_remove_ordered_extent(inode, ordered);
9320                         btrfs_put_ordered_extent(ordered);
9321                         btrfs_put_ordered_extent(ordered);
9322                 }
9323         }
9324         btrfs_qgroup_check_reserved_leak(inode);
9325         inode_tree_del(inode);
9326         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9327 free:
9328         call_rcu(&inode->i_rcu, btrfs_i_callback);
9329 }
9330
9331 int btrfs_drop_inode(struct inode *inode)
9332 {
9333         struct btrfs_root *root = BTRFS_I(inode)->root;
9334
9335         if (root == NULL)
9336                 return 1;
9337
9338         /* the snap/subvol tree is on deleting */
9339         if (btrfs_root_refs(&root->root_item) == 0)
9340                 return 1;
9341         else
9342                 return generic_drop_inode(inode);
9343 }
9344
9345 static void init_once(void *foo)
9346 {
9347         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9348
9349         inode_init_once(&ei->vfs_inode);
9350 }
9351
9352 void btrfs_destroy_cachep(void)
9353 {
9354         /*
9355          * Make sure all delayed rcu free inodes are flushed before we
9356          * destroy cache.
9357          */
9358         rcu_barrier();
9359         kmem_cache_destroy(btrfs_inode_cachep);
9360         kmem_cache_destroy(btrfs_trans_handle_cachep);
9361         kmem_cache_destroy(btrfs_transaction_cachep);
9362         kmem_cache_destroy(btrfs_path_cachep);
9363         kmem_cache_destroy(btrfs_free_space_cachep);
9364 }
9365
9366 int btrfs_init_cachep(void)
9367 {
9368         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9369                         sizeof(struct btrfs_inode), 0,
9370                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9371                         init_once);
9372         if (!btrfs_inode_cachep)
9373                 goto fail;
9374
9375         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9376                         sizeof(struct btrfs_trans_handle), 0,
9377                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9378         if (!btrfs_trans_handle_cachep)
9379                 goto fail;
9380
9381         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9382                         sizeof(struct btrfs_transaction), 0,
9383                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9384         if (!btrfs_transaction_cachep)
9385                 goto fail;
9386
9387         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9388                         sizeof(struct btrfs_path), 0,
9389                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9390         if (!btrfs_path_cachep)
9391                 goto fail;
9392
9393         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9394                         sizeof(struct btrfs_free_space), 0,
9395                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9396         if (!btrfs_free_space_cachep)
9397                 goto fail;
9398
9399         return 0;
9400 fail:
9401         btrfs_destroy_cachep();
9402         return -ENOMEM;
9403 }
9404
9405 static int btrfs_getattr(struct vfsmount *mnt,
9406                          struct dentry *dentry, struct kstat *stat)
9407 {
9408         u64 delalloc_bytes;
9409         struct inode *inode = d_inode(dentry);
9410         u32 blocksize = inode->i_sb->s_blocksize;
9411
9412         generic_fillattr(inode, stat);
9413         stat->dev = BTRFS_I(inode)->root->anon_dev;
9414
9415         spin_lock(&BTRFS_I(inode)->lock);
9416         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9417         spin_unlock(&BTRFS_I(inode)->lock);
9418         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9419                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9420         return 0;
9421 }
9422
9423 static int btrfs_rename_exchange(struct inode *old_dir,
9424                               struct dentry *old_dentry,
9425                               struct inode *new_dir,
9426                               struct dentry *new_dentry)
9427 {
9428         struct btrfs_trans_handle *trans;
9429         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9430         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9431         struct inode *new_inode = new_dentry->d_inode;
9432         struct inode *old_inode = old_dentry->d_inode;
9433         struct timespec ctime = CURRENT_TIME;
9434         struct dentry *parent;
9435         u64 old_ino = btrfs_ino(old_inode);
9436         u64 new_ino = btrfs_ino(new_inode);
9437         u64 old_idx = 0;
9438         u64 new_idx = 0;
9439         u64 root_objectid;
9440         int ret;
9441         bool root_log_pinned = false;
9442         bool dest_log_pinned = false;
9443
9444         /* we only allow rename subvolume link between subvolumes */
9445         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9446                 return -EXDEV;
9447
9448         /* close the race window with snapshot create/destroy ioctl */
9449         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9450                 down_read(&root->fs_info->subvol_sem);
9451         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9452                 down_read(&dest->fs_info->subvol_sem);
9453
9454         /*
9455          * We want to reserve the absolute worst case amount of items.  So if
9456          * both inodes are subvols and we need to unlink them then that would
9457          * require 4 item modifications, but if they are both normal inodes it
9458          * would require 5 item modifications, so we'll assume their normal
9459          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9460          * should cover the worst case number of items we'll modify.
9461          */
9462         trans = btrfs_start_transaction(root, 12);
9463         if (IS_ERR(trans)) {
9464                 ret = PTR_ERR(trans);
9465                 goto out_notrans;
9466         }
9467
9468         /*
9469          * We need to find a free sequence number both in the source and
9470          * in the destination directory for the exchange.
9471          */
9472         ret = btrfs_set_inode_index(new_dir, &old_idx);
9473         if (ret)
9474                 goto out_fail;
9475         ret = btrfs_set_inode_index(old_dir, &new_idx);
9476         if (ret)
9477                 goto out_fail;
9478
9479         BTRFS_I(old_inode)->dir_index = 0ULL;
9480         BTRFS_I(new_inode)->dir_index = 0ULL;
9481
9482         /* Reference for the source. */
9483         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9484                 /* force full log commit if subvolume involved. */
9485                 btrfs_set_log_full_commit(root->fs_info, trans);
9486         } else {
9487                 btrfs_pin_log_trans(root);
9488                 root_log_pinned = true;
9489                 ret = btrfs_insert_inode_ref(trans, dest,
9490                                              new_dentry->d_name.name,
9491                                              new_dentry->d_name.len,
9492                                              old_ino,
9493                                              btrfs_ino(new_dir), old_idx);
9494                 if (ret)
9495                         goto out_fail;
9496         }
9497
9498         /* And now for the dest. */
9499         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9500                 /* force full log commit if subvolume involved. */
9501                 btrfs_set_log_full_commit(dest->fs_info, trans);
9502         } else {
9503                 btrfs_pin_log_trans(dest);
9504                 dest_log_pinned = true;
9505                 ret = btrfs_insert_inode_ref(trans, root,
9506                                              old_dentry->d_name.name,
9507                                              old_dentry->d_name.len,
9508                                              new_ino,
9509                                              btrfs_ino(old_dir), new_idx);
9510                 if (ret)
9511                         goto out_fail;
9512         }
9513
9514         /* Update inode version and ctime/mtime. */
9515         inode_inc_iversion(old_dir);
9516         inode_inc_iversion(new_dir);
9517         inode_inc_iversion(old_inode);
9518         inode_inc_iversion(new_inode);
9519         old_dir->i_ctime = old_dir->i_mtime = ctime;
9520         new_dir->i_ctime = new_dir->i_mtime = ctime;
9521         old_inode->i_ctime = ctime;
9522         new_inode->i_ctime = ctime;
9523
9524         if (old_dentry->d_parent != new_dentry->d_parent) {
9525                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9526                 btrfs_record_unlink_dir(trans, new_dir, new_inode, 1);
9527         }
9528
9529         /* src is a subvolume */
9530         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9531                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9532                 ret = btrfs_unlink_subvol(trans, root, old_dir,
9533                                           root_objectid,
9534                                           old_dentry->d_name.name,
9535                                           old_dentry->d_name.len);
9536         } else { /* src is an inode */
9537                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9538                                            old_dentry->d_inode,
9539                                            old_dentry->d_name.name,
9540                                            old_dentry->d_name.len);
9541                 if (!ret)
9542                         ret = btrfs_update_inode(trans, root, old_inode);
9543         }
9544         if (ret) {
9545                 btrfs_abort_transaction(trans, root, ret);
9546                 goto out_fail;
9547         }
9548
9549         /* dest is a subvolume */
9550         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9551                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9552                 ret = btrfs_unlink_subvol(trans, dest, new_dir,
9553                                           root_objectid,
9554                                           new_dentry->d_name.name,
9555                                           new_dentry->d_name.len);
9556         } else { /* dest is an inode */
9557                 ret = __btrfs_unlink_inode(trans, dest, new_dir,
9558                                            new_dentry->d_inode,
9559                                            new_dentry->d_name.name,
9560                                            new_dentry->d_name.len);
9561                 if (!ret)
9562                         ret = btrfs_update_inode(trans, dest, new_inode);
9563         }
9564         if (ret) {
9565                 btrfs_abort_transaction(trans, root, ret);
9566                 goto out_fail;
9567         }
9568
9569         ret = btrfs_add_link(trans, new_dir, old_inode,
9570                              new_dentry->d_name.name,
9571                              new_dentry->d_name.len, 0, old_idx);
9572         if (ret) {
9573                 btrfs_abort_transaction(trans, root, ret);
9574                 goto out_fail;
9575         }
9576
9577         ret = btrfs_add_link(trans, old_dir, new_inode,
9578                              old_dentry->d_name.name,
9579                              old_dentry->d_name.len, 0, new_idx);
9580         if (ret) {
9581                 btrfs_abort_transaction(trans, root, ret);
9582                 goto out_fail;
9583         }
9584
9585         if (old_inode->i_nlink == 1)
9586                 BTRFS_I(old_inode)->dir_index = old_idx;
9587         if (new_inode->i_nlink == 1)
9588                 BTRFS_I(new_inode)->dir_index = new_idx;
9589
9590         if (root_log_pinned) {
9591                 parent = new_dentry->d_parent;
9592                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9593                 btrfs_end_log_trans(root);
9594                 root_log_pinned = false;
9595         }
9596         if (dest_log_pinned) {
9597                 parent = old_dentry->d_parent;
9598                 btrfs_log_new_name(trans, new_inode, new_dir, parent);
9599                 btrfs_end_log_trans(dest);
9600                 dest_log_pinned = false;
9601         }
9602 out_fail:
9603         /*
9604          * If we have pinned a log and an error happened, we unpin tasks
9605          * trying to sync the log and force them to fallback to a transaction
9606          * commit if the log currently contains any of the inodes involved in
9607          * this rename operation (to ensure we do not persist a log with an
9608          * inconsistent state for any of these inodes or leading to any
9609          * inconsistencies when replayed). If the transaction was aborted, the
9610          * abortion reason is propagated to userspace when attempting to commit
9611          * the transaction. If the log does not contain any of these inodes, we
9612          * allow the tasks to sync it.
9613          */
9614         if (ret && (root_log_pinned || dest_log_pinned)) {
9615                 if (btrfs_inode_in_log(old_dir, root->fs_info->generation) ||
9616                     btrfs_inode_in_log(new_dir, root->fs_info->generation) ||
9617                     btrfs_inode_in_log(old_inode, root->fs_info->generation) ||
9618                     (new_inode &&
9619                      btrfs_inode_in_log(new_inode, root->fs_info->generation)))
9620                     btrfs_set_log_full_commit(root->fs_info, trans);
9621
9622                 if (root_log_pinned) {
9623                         btrfs_end_log_trans(root);
9624                         root_log_pinned = false;
9625                 }
9626                 if (dest_log_pinned) {
9627                         btrfs_end_log_trans(dest);
9628                         dest_log_pinned = false;
9629                 }
9630         }
9631         ret = btrfs_end_transaction(trans, root);
9632 out_notrans:
9633         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9634                 up_read(&dest->fs_info->subvol_sem);
9635         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9636                 up_read(&root->fs_info->subvol_sem);
9637
9638         return ret;
9639 }
9640
9641 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9642                                      struct btrfs_root *root,
9643                                      struct inode *dir,
9644                                      struct dentry *dentry)
9645 {
9646         int ret;
9647         struct inode *inode;
9648         u64 objectid;
9649         u64 index;
9650
9651         ret = btrfs_find_free_ino(root, &objectid);
9652         if (ret)
9653                 return ret;
9654
9655         inode = btrfs_new_inode(trans, root, dir,
9656                                 dentry->d_name.name,
9657                                 dentry->d_name.len,
9658                                 btrfs_ino(dir),
9659                                 objectid,
9660                                 S_IFCHR | WHITEOUT_MODE,
9661                                 &index);
9662
9663         if (IS_ERR(inode)) {
9664                 ret = PTR_ERR(inode);
9665                 return ret;
9666         }
9667
9668         inode->i_op = &btrfs_special_inode_operations;
9669         init_special_inode(inode, inode->i_mode,
9670                 WHITEOUT_DEV);
9671
9672         ret = btrfs_init_inode_security(trans, inode, dir,
9673                                 &dentry->d_name);
9674         if (ret)
9675                 goto out;
9676
9677         ret = btrfs_add_nondir(trans, dir, dentry,
9678                                 inode, 0, index);
9679         if (ret)
9680                 goto out;
9681
9682         ret = btrfs_update_inode(trans, root, inode);
9683 out:
9684         unlock_new_inode(inode);
9685         if (ret)
9686                 inode_dec_link_count(inode);
9687         iput(inode);
9688
9689         return ret;
9690 }
9691
9692 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9693                            struct inode *new_dir, struct dentry *new_dentry,
9694                            unsigned int flags)
9695 {
9696         struct btrfs_trans_handle *trans;
9697         unsigned int trans_num_items;
9698         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9699         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9700         struct inode *new_inode = d_inode(new_dentry);
9701         struct inode *old_inode = d_inode(old_dentry);
9702         u64 index = 0;
9703         u64 root_objectid;
9704         int ret;
9705         u64 old_ino = btrfs_ino(old_inode);
9706         bool log_pinned = false;
9707
9708         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9709                 return -EPERM;
9710
9711         /* we only allow rename subvolume link between subvolumes */
9712         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9713                 return -EXDEV;
9714
9715         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9716             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
9717                 return -ENOTEMPTY;
9718
9719         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9720             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9721                 return -ENOTEMPTY;
9722
9723
9724         /* check for collisions, even if the  name isn't there */
9725         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9726                              new_dentry->d_name.name,
9727                              new_dentry->d_name.len);
9728
9729         if (ret) {
9730                 if (ret == -EEXIST) {
9731                         /* we shouldn't get
9732                          * eexist without a new_inode */
9733                         if (WARN_ON(!new_inode)) {
9734                                 return ret;
9735                         }
9736                 } else {
9737                         /* maybe -EOVERFLOW */
9738                         return ret;
9739                 }
9740         }
9741         ret = 0;
9742
9743         /*
9744          * we're using rename to replace one file with another.  Start IO on it
9745          * now so  we don't add too much work to the end of the transaction
9746          */
9747         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9748                 filemap_flush(old_inode->i_mapping);
9749
9750         /* close the racy window with snapshot create/destroy ioctl */
9751         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9752                 down_read(&root->fs_info->subvol_sem);
9753         /*
9754          * We want to reserve the absolute worst case amount of items.  So if
9755          * both inodes are subvols and we need to unlink them then that would
9756          * require 4 item modifications, but if they are both normal inodes it
9757          * would require 5 item modifications, so we'll assume they are normal
9758          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9759          * should cover the worst case number of items we'll modify.
9760          * If our rename has the whiteout flag, we need more 5 units for the
9761          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9762          * when selinux is enabled).
9763          */
9764         trans_num_items = 11;
9765         if (flags & RENAME_WHITEOUT)
9766                 trans_num_items += 5;
9767         trans = btrfs_start_transaction(root, trans_num_items);
9768         if (IS_ERR(trans)) {
9769                 ret = PTR_ERR(trans);
9770                 goto out_notrans;
9771         }
9772
9773         if (dest != root)
9774                 btrfs_record_root_in_trans(trans, dest);
9775
9776         ret = btrfs_set_inode_index(new_dir, &index);
9777         if (ret)
9778                 goto out_fail;
9779
9780         BTRFS_I(old_inode)->dir_index = 0ULL;
9781         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9782                 /* force full log commit if subvolume involved. */
9783                 btrfs_set_log_full_commit(root->fs_info, trans);
9784         } else {
9785                 btrfs_pin_log_trans(root);
9786                 log_pinned = true;
9787                 ret = btrfs_insert_inode_ref(trans, dest,
9788                                              new_dentry->d_name.name,
9789                                              new_dentry->d_name.len,
9790                                              old_ino,
9791                                              btrfs_ino(new_dir), index);
9792                 if (ret)
9793                         goto out_fail;
9794         }
9795
9796         inode_inc_iversion(old_dir);
9797         inode_inc_iversion(new_dir);
9798         inode_inc_iversion(old_inode);
9799         old_dir->i_ctime = old_dir->i_mtime =
9800         new_dir->i_ctime = new_dir->i_mtime =
9801         old_inode->i_ctime = current_fs_time(old_dir->i_sb);
9802
9803         if (old_dentry->d_parent != new_dentry->d_parent)
9804                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9805
9806         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9807                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9808                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9809                                         old_dentry->d_name.name,
9810                                         old_dentry->d_name.len);
9811         } else {
9812                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9813                                         d_inode(old_dentry),
9814                                         old_dentry->d_name.name,
9815                                         old_dentry->d_name.len);
9816                 if (!ret)
9817                         ret = btrfs_update_inode(trans, root, old_inode);
9818         }
9819         if (ret) {
9820                 btrfs_abort_transaction(trans, root, ret);
9821                 goto out_fail;
9822         }
9823
9824         if (new_inode) {
9825                 inode_inc_iversion(new_inode);
9826                 new_inode->i_ctime = current_fs_time(new_inode->i_sb);
9827                 if (unlikely(btrfs_ino(new_inode) ==
9828                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9829                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9830                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9831                                                 root_objectid,
9832                                                 new_dentry->d_name.name,
9833                                                 new_dentry->d_name.len);
9834                         BUG_ON(new_inode->i_nlink == 0);
9835                 } else {
9836                         ret = btrfs_unlink_inode(trans, dest, new_dir,
9837                                                  d_inode(new_dentry),
9838                                                  new_dentry->d_name.name,
9839                                                  new_dentry->d_name.len);
9840                 }
9841                 if (!ret && new_inode->i_nlink == 0)
9842                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9843                 if (ret) {
9844                         btrfs_abort_transaction(trans, root, ret);
9845                         goto out_fail;
9846                 }
9847         }
9848
9849         ret = btrfs_add_link(trans, new_dir, old_inode,
9850                              new_dentry->d_name.name,
9851                              new_dentry->d_name.len, 0, index);
9852         if (ret) {
9853                 btrfs_abort_transaction(trans, root, ret);
9854                 goto out_fail;
9855         }
9856
9857         if (old_inode->i_nlink == 1)
9858                 BTRFS_I(old_inode)->dir_index = index;
9859
9860         if (log_pinned) {
9861                 struct dentry *parent = new_dentry->d_parent;
9862
9863                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9864                 btrfs_end_log_trans(root);
9865                 log_pinned = false;
9866         }
9867
9868         if (flags & RENAME_WHITEOUT) {
9869                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9870                                                 old_dentry);
9871
9872                 if (ret) {
9873                         btrfs_abort_transaction(trans, root, ret);
9874                         goto out_fail;
9875                 }
9876         }
9877 out_fail:
9878         /*
9879          * If we have pinned the log and an error happened, we unpin tasks
9880          * trying to sync the log and force them to fallback to a transaction
9881          * commit if the log currently contains any of the inodes involved in
9882          * this rename operation (to ensure we do not persist a log with an
9883          * inconsistent state for any of these inodes or leading to any
9884          * inconsistencies when replayed). If the transaction was aborted, the
9885          * abortion reason is propagated to userspace when attempting to commit
9886          * the transaction. If the log does not contain any of these inodes, we
9887          * allow the tasks to sync it.
9888          */
9889         if (ret && log_pinned) {
9890                 if (btrfs_inode_in_log(old_dir, root->fs_info->generation) ||
9891                     btrfs_inode_in_log(new_dir, root->fs_info->generation) ||
9892                     btrfs_inode_in_log(old_inode, root->fs_info->generation) ||
9893                     (new_inode &&
9894                      btrfs_inode_in_log(new_inode, root->fs_info->generation)))
9895                     btrfs_set_log_full_commit(root->fs_info, trans);
9896
9897                 btrfs_end_log_trans(root);
9898                 log_pinned = false;
9899         }
9900         btrfs_end_transaction(trans, root);
9901 out_notrans:
9902         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9903                 up_read(&root->fs_info->subvol_sem);
9904
9905         return ret;
9906 }
9907
9908 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9909                          struct inode *new_dir, struct dentry *new_dentry,
9910                          unsigned int flags)
9911 {
9912         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9913                 return -EINVAL;
9914
9915         if (flags & RENAME_EXCHANGE)
9916                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9917                                           new_dentry);
9918
9919         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9920 }
9921
9922 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9923 {
9924         struct btrfs_delalloc_work *delalloc_work;
9925         struct inode *inode;
9926
9927         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9928                                      work);
9929         inode = delalloc_work->inode;
9930         filemap_flush(inode->i_mapping);
9931         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9932                                 &BTRFS_I(inode)->runtime_flags))
9933                 filemap_flush(inode->i_mapping);
9934
9935         if (delalloc_work->delay_iput)
9936                 btrfs_add_delayed_iput(inode);
9937         else
9938                 iput(inode);
9939         complete(&delalloc_work->completion);
9940 }
9941
9942 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
9943                                                     int delay_iput)
9944 {
9945         struct btrfs_delalloc_work *work;
9946
9947         work = kmalloc(sizeof(*work), GFP_NOFS);
9948         if (!work)
9949                 return NULL;
9950
9951         init_completion(&work->completion);
9952         INIT_LIST_HEAD(&work->list);
9953         work->inode = inode;
9954         work->delay_iput = delay_iput;
9955         WARN_ON_ONCE(!inode);
9956         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9957                         btrfs_run_delalloc_work, NULL, NULL);
9958
9959         return work;
9960 }
9961
9962 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9963 {
9964         wait_for_completion(&work->completion);
9965         kfree(work);
9966 }
9967
9968 /*
9969  * some fairly slow code that needs optimization. This walks the list
9970  * of all the inodes with pending delalloc and forces them to disk.
9971  */
9972 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9973                                    int nr)
9974 {
9975         struct btrfs_inode *binode;
9976         struct inode *inode;
9977         struct btrfs_delalloc_work *work, *next;
9978         struct list_head works;
9979         struct list_head splice;
9980         int ret = 0;
9981
9982         INIT_LIST_HEAD(&works);
9983         INIT_LIST_HEAD(&splice);
9984
9985         mutex_lock(&root->delalloc_mutex);
9986         spin_lock(&root->delalloc_lock);
9987         list_splice_init(&root->delalloc_inodes, &splice);
9988         while (!list_empty(&splice)) {
9989                 binode = list_entry(splice.next, struct btrfs_inode,
9990                                     delalloc_inodes);
9991
9992                 list_move_tail(&binode->delalloc_inodes,
9993                                &root->delalloc_inodes);
9994                 inode = igrab(&binode->vfs_inode);
9995                 if (!inode) {
9996                         cond_resched_lock(&root->delalloc_lock);
9997                         continue;
9998                 }
9999                 spin_unlock(&root->delalloc_lock);
10000
10001                 work = btrfs_alloc_delalloc_work(inode, delay_iput);
10002                 if (!work) {
10003                         if (delay_iput)
10004                                 btrfs_add_delayed_iput(inode);
10005                         else
10006                                 iput(inode);
10007                         ret = -ENOMEM;
10008                         goto out;
10009                 }
10010                 list_add_tail(&work->list, &works);
10011                 btrfs_queue_work(root->fs_info->flush_workers,
10012                                  &work->work);
10013                 ret++;
10014                 if (nr != -1 && ret >= nr)
10015                         goto out;
10016                 cond_resched();
10017                 spin_lock(&root->delalloc_lock);
10018         }
10019         spin_unlock(&root->delalloc_lock);
10020
10021 out:
10022         list_for_each_entry_safe(work, next, &works, list) {
10023                 list_del_init(&work->list);
10024                 btrfs_wait_and_free_delalloc_work(work);
10025         }
10026
10027         if (!list_empty_careful(&splice)) {
10028                 spin_lock(&root->delalloc_lock);
10029                 list_splice_tail(&splice, &root->delalloc_inodes);
10030                 spin_unlock(&root->delalloc_lock);
10031         }
10032         mutex_unlock(&root->delalloc_mutex);
10033         return ret;
10034 }
10035
10036 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
10037 {
10038         int ret;
10039
10040         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
10041                 return -EROFS;
10042
10043         ret = __start_delalloc_inodes(root, delay_iput, -1);
10044         if (ret > 0)
10045                 ret = 0;
10046         /*
10047          * the filemap_flush will queue IO into the worker threads, but
10048          * we have to make sure the IO is actually started and that
10049          * ordered extents get created before we return
10050          */
10051         atomic_inc(&root->fs_info->async_submit_draining);
10052         while (atomic_read(&root->fs_info->nr_async_submits) ||
10053               atomic_read(&root->fs_info->async_delalloc_pages)) {
10054                 wait_event(root->fs_info->async_submit_wait,
10055                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
10056                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
10057         }
10058         atomic_dec(&root->fs_info->async_submit_draining);
10059         return ret;
10060 }
10061
10062 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
10063                                int nr)
10064 {
10065         struct btrfs_root *root;
10066         struct list_head splice;
10067         int ret;
10068
10069         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10070                 return -EROFS;
10071
10072         INIT_LIST_HEAD(&splice);
10073
10074         mutex_lock(&fs_info->delalloc_root_mutex);
10075         spin_lock(&fs_info->delalloc_root_lock);
10076         list_splice_init(&fs_info->delalloc_roots, &splice);
10077         while (!list_empty(&splice) && nr) {
10078                 root = list_first_entry(&splice, struct btrfs_root,
10079                                         delalloc_root);
10080                 root = btrfs_grab_fs_root(root);
10081                 BUG_ON(!root);
10082                 list_move_tail(&root->delalloc_root,
10083                                &fs_info->delalloc_roots);
10084                 spin_unlock(&fs_info->delalloc_root_lock);
10085
10086                 ret = __start_delalloc_inodes(root, delay_iput, nr);
10087                 btrfs_put_fs_root(root);
10088                 if (ret < 0)
10089                         goto out;
10090
10091                 if (nr != -1) {
10092                         nr -= ret;
10093                         WARN_ON(nr < 0);
10094                 }
10095                 spin_lock(&fs_info->delalloc_root_lock);
10096         }
10097         spin_unlock(&fs_info->delalloc_root_lock);
10098
10099         ret = 0;
10100         atomic_inc(&fs_info->async_submit_draining);
10101         while (atomic_read(&fs_info->nr_async_submits) ||
10102               atomic_read(&fs_info->async_delalloc_pages)) {
10103                 wait_event(fs_info->async_submit_wait,
10104                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
10105                     atomic_read(&fs_info->async_delalloc_pages) == 0));
10106         }
10107         atomic_dec(&fs_info->async_submit_draining);
10108 out:
10109         if (!list_empty_careful(&splice)) {
10110                 spin_lock(&fs_info->delalloc_root_lock);
10111                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10112                 spin_unlock(&fs_info->delalloc_root_lock);
10113         }
10114         mutex_unlock(&fs_info->delalloc_root_mutex);
10115         return ret;
10116 }
10117
10118 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10119                          const char *symname)
10120 {
10121         struct btrfs_trans_handle *trans;
10122         struct btrfs_root *root = BTRFS_I(dir)->root;
10123         struct btrfs_path *path;
10124         struct btrfs_key key;
10125         struct inode *inode = NULL;
10126         int err;
10127         int drop_inode = 0;
10128         u64 objectid;
10129         u64 index = 0;
10130         int name_len;
10131         int datasize;
10132         unsigned long ptr;
10133         struct btrfs_file_extent_item *ei;
10134         struct extent_buffer *leaf;
10135
10136         name_len = strlen(symname);
10137         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
10138                 return -ENAMETOOLONG;
10139
10140         /*
10141          * 2 items for inode item and ref
10142          * 2 items for dir items
10143          * 1 item for updating parent inode item
10144          * 1 item for the inline extent item
10145          * 1 item for xattr if selinux is on
10146          */
10147         trans = btrfs_start_transaction(root, 7);
10148         if (IS_ERR(trans))
10149                 return PTR_ERR(trans);
10150
10151         err = btrfs_find_free_ino(root, &objectid);
10152         if (err)
10153                 goto out_unlock;
10154
10155         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10156                                 dentry->d_name.len, btrfs_ino(dir), objectid,
10157                                 S_IFLNK|S_IRWXUGO, &index);
10158         if (IS_ERR(inode)) {
10159                 err = PTR_ERR(inode);
10160                 goto out_unlock;
10161         }
10162
10163         /*
10164         * If the active LSM wants to access the inode during
10165         * d_instantiate it needs these. Smack checks to see
10166         * if the filesystem supports xattrs by looking at the
10167         * ops vector.
10168         */
10169         inode->i_fop = &btrfs_file_operations;
10170         inode->i_op = &btrfs_file_inode_operations;
10171         inode->i_mapping->a_ops = &btrfs_aops;
10172         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10173
10174         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10175         if (err)
10176                 goto out_unlock_inode;
10177
10178         path = btrfs_alloc_path();
10179         if (!path) {
10180                 err = -ENOMEM;
10181                 goto out_unlock_inode;
10182         }
10183         key.objectid = btrfs_ino(inode);
10184         key.offset = 0;
10185         key.type = BTRFS_EXTENT_DATA_KEY;
10186         datasize = btrfs_file_extent_calc_inline_size(name_len);
10187         err = btrfs_insert_empty_item(trans, root, path, &key,
10188                                       datasize);
10189         if (err) {
10190                 btrfs_free_path(path);
10191                 goto out_unlock_inode;
10192         }
10193         leaf = path->nodes[0];
10194         ei = btrfs_item_ptr(leaf, path->slots[0],
10195                             struct btrfs_file_extent_item);
10196         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10197         btrfs_set_file_extent_type(leaf, ei,
10198                                    BTRFS_FILE_EXTENT_INLINE);
10199         btrfs_set_file_extent_encryption(leaf, ei, 0);
10200         btrfs_set_file_extent_compression(leaf, ei, 0);
10201         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10202         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10203
10204         ptr = btrfs_file_extent_inline_start(ei);
10205         write_extent_buffer(leaf, symname, ptr, name_len);
10206         btrfs_mark_buffer_dirty(leaf);
10207         btrfs_free_path(path);
10208
10209         inode->i_op = &btrfs_symlink_inode_operations;
10210         inode_nohighmem(inode);
10211         inode->i_mapping->a_ops = &btrfs_symlink_aops;
10212         inode_set_bytes(inode, name_len);
10213         btrfs_i_size_write(inode, name_len);
10214         err = btrfs_update_inode(trans, root, inode);
10215         /*
10216          * Last step, add directory indexes for our symlink inode. This is the
10217          * last step to avoid extra cleanup of these indexes if an error happens
10218          * elsewhere above.
10219          */
10220         if (!err)
10221                 err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
10222         if (err) {
10223                 drop_inode = 1;
10224                 goto out_unlock_inode;
10225         }
10226
10227         unlock_new_inode(inode);
10228         d_instantiate(dentry, inode);
10229
10230 out_unlock:
10231         btrfs_end_transaction(trans, root);
10232         if (drop_inode) {
10233                 inode_dec_link_count(inode);
10234                 iput(inode);
10235         }
10236         btrfs_btree_balance_dirty(root);
10237         return err;
10238
10239 out_unlock_inode:
10240         drop_inode = 1;
10241         unlock_new_inode(inode);
10242         goto out_unlock;
10243 }
10244
10245 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10246                                        u64 start, u64 num_bytes, u64 min_size,
10247                                        loff_t actual_len, u64 *alloc_hint,
10248                                        struct btrfs_trans_handle *trans)
10249 {
10250         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10251         struct extent_map *em;
10252         struct btrfs_root *root = BTRFS_I(inode)->root;
10253         struct btrfs_key ins;
10254         u64 cur_offset = start;
10255         u64 i_size;
10256         u64 cur_bytes;
10257         u64 last_alloc = (u64)-1;
10258         int ret = 0;
10259         bool own_trans = true;
10260
10261         if (trans)
10262                 own_trans = false;
10263         while (num_bytes > 0) {
10264                 if (own_trans) {
10265                         trans = btrfs_start_transaction(root, 3);
10266                         if (IS_ERR(trans)) {
10267                                 ret = PTR_ERR(trans);
10268                                 break;
10269                         }
10270                 }
10271
10272                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10273                 cur_bytes = max(cur_bytes, min_size);
10274                 /*
10275                  * If we are severely fragmented we could end up with really
10276                  * small allocations, so if the allocator is returning small
10277                  * chunks lets make its job easier by only searching for those
10278                  * sized chunks.
10279                  */
10280                 cur_bytes = min(cur_bytes, last_alloc);
10281                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
10282                                            *alloc_hint, &ins, 1, 0);
10283                 if (ret) {
10284                         if (own_trans)
10285                                 btrfs_end_transaction(trans, root);
10286                         break;
10287                 }
10288                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
10289
10290                 last_alloc = ins.offset;
10291                 ret = insert_reserved_file_extent(trans, inode,
10292                                                   cur_offset, ins.objectid,
10293                                                   ins.offset, ins.offset,
10294                                                   ins.offset, 0, 0, 0,
10295                                                   BTRFS_FILE_EXTENT_PREALLOC);
10296                 if (ret) {
10297                         btrfs_free_reserved_extent(root, ins.objectid,
10298                                                    ins.offset, 0);
10299                         btrfs_abort_transaction(trans, root, ret);
10300                         if (own_trans)
10301                                 btrfs_end_transaction(trans, root);
10302                         break;
10303                 }
10304
10305                 btrfs_drop_extent_cache(inode, cur_offset,
10306                                         cur_offset + ins.offset -1, 0);
10307
10308                 em = alloc_extent_map();
10309                 if (!em) {
10310                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10311                                 &BTRFS_I(inode)->runtime_flags);
10312                         goto next;
10313                 }
10314
10315                 em->start = cur_offset;
10316                 em->orig_start = cur_offset;
10317                 em->len = ins.offset;
10318                 em->block_start = ins.objectid;
10319                 em->block_len = ins.offset;
10320                 em->orig_block_len = ins.offset;
10321                 em->ram_bytes = ins.offset;
10322                 em->bdev = root->fs_info->fs_devices->latest_bdev;
10323                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10324                 em->generation = trans->transid;
10325
10326                 while (1) {
10327                         write_lock(&em_tree->lock);
10328                         ret = add_extent_mapping(em_tree, em, 1);
10329                         write_unlock(&em_tree->lock);
10330                         if (ret != -EEXIST)
10331                                 break;
10332                         btrfs_drop_extent_cache(inode, cur_offset,
10333                                                 cur_offset + ins.offset - 1,
10334                                                 0);
10335                 }
10336                 free_extent_map(em);
10337 next:
10338                 num_bytes -= ins.offset;
10339                 cur_offset += ins.offset;
10340                 *alloc_hint = ins.objectid + ins.offset;
10341
10342                 inode_inc_iversion(inode);
10343                 inode->i_ctime = current_fs_time(inode->i_sb);
10344                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10345                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10346                     (actual_len > inode->i_size) &&
10347                     (cur_offset > inode->i_size)) {
10348                         if (cur_offset > actual_len)
10349                                 i_size = actual_len;
10350                         else
10351                                 i_size = cur_offset;
10352                         i_size_write(inode, i_size);
10353                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10354                 }
10355
10356                 ret = btrfs_update_inode(trans, root, inode);
10357
10358                 if (ret) {
10359                         btrfs_abort_transaction(trans, root, ret);
10360                         if (own_trans)
10361                                 btrfs_end_transaction(trans, root);
10362                         break;
10363                 }
10364
10365                 if (own_trans)
10366                         btrfs_end_transaction(trans, root);
10367         }
10368         return ret;
10369 }
10370
10371 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10372                               u64 start, u64 num_bytes, u64 min_size,
10373                               loff_t actual_len, u64 *alloc_hint)
10374 {
10375         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10376                                            min_size, actual_len, alloc_hint,
10377                                            NULL);
10378 }
10379
10380 int btrfs_prealloc_file_range_trans(struct inode *inode,
10381                                     struct btrfs_trans_handle *trans, int mode,
10382                                     u64 start, u64 num_bytes, u64 min_size,
10383                                     loff_t actual_len, u64 *alloc_hint)
10384 {
10385         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10386                                            min_size, actual_len, alloc_hint, trans);
10387 }
10388
10389 static int btrfs_set_page_dirty(struct page *page)
10390 {
10391         return __set_page_dirty_nobuffers(page);
10392 }
10393
10394 static int btrfs_permission(struct inode *inode, int mask)
10395 {
10396         struct btrfs_root *root = BTRFS_I(inode)->root;
10397         umode_t mode = inode->i_mode;
10398
10399         if (mask & MAY_WRITE &&
10400             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10401                 if (btrfs_root_readonly(root))
10402                         return -EROFS;
10403                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10404                         return -EACCES;
10405         }
10406         return generic_permission(inode, mask);
10407 }
10408
10409 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10410 {
10411         struct btrfs_trans_handle *trans;
10412         struct btrfs_root *root = BTRFS_I(dir)->root;
10413         struct inode *inode = NULL;
10414         u64 objectid;
10415         u64 index;
10416         int ret = 0;
10417
10418         /*
10419          * 5 units required for adding orphan entry
10420          */
10421         trans = btrfs_start_transaction(root, 5);
10422         if (IS_ERR(trans))
10423                 return PTR_ERR(trans);
10424
10425         ret = btrfs_find_free_ino(root, &objectid);
10426         if (ret)
10427                 goto out;
10428
10429         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10430                                 btrfs_ino(dir), objectid, mode, &index);
10431         if (IS_ERR(inode)) {
10432                 ret = PTR_ERR(inode);
10433                 inode = NULL;
10434                 goto out;
10435         }
10436
10437         inode->i_fop = &btrfs_file_operations;
10438         inode->i_op = &btrfs_file_inode_operations;
10439
10440         inode->i_mapping->a_ops = &btrfs_aops;
10441         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10442
10443         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10444         if (ret)
10445                 goto out_inode;
10446
10447         ret = btrfs_update_inode(trans, root, inode);
10448         if (ret)
10449                 goto out_inode;
10450         ret = btrfs_orphan_add(trans, inode);
10451         if (ret)
10452                 goto out_inode;
10453
10454         /*
10455          * We set number of links to 0 in btrfs_new_inode(), and here we set
10456          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10457          * through:
10458          *
10459          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10460          */
10461         set_nlink(inode, 1);
10462         unlock_new_inode(inode);
10463         d_tmpfile(dentry, inode);
10464         mark_inode_dirty(inode);
10465
10466 out:
10467         btrfs_end_transaction(trans, root);
10468         if (ret)
10469                 iput(inode);
10470         btrfs_balance_delayed_items(root);
10471         btrfs_btree_balance_dirty(root);
10472         return ret;
10473
10474 out_inode:
10475         unlock_new_inode(inode);
10476         goto out;
10477
10478 }
10479
10480 /* Inspired by filemap_check_errors() */
10481 int btrfs_inode_check_errors(struct inode *inode)
10482 {
10483         int ret = 0;
10484
10485         if (test_bit(AS_ENOSPC, &inode->i_mapping->flags) &&
10486             test_and_clear_bit(AS_ENOSPC, &inode->i_mapping->flags))
10487                 ret = -ENOSPC;
10488         if (test_bit(AS_EIO, &inode->i_mapping->flags) &&
10489             test_and_clear_bit(AS_EIO, &inode->i_mapping->flags))
10490                 ret = -EIO;
10491
10492         return ret;
10493 }
10494
10495 static const struct inode_operations btrfs_dir_inode_operations = {
10496         .getattr        = btrfs_getattr,
10497         .lookup         = btrfs_lookup,
10498         .create         = btrfs_create,
10499         .unlink         = btrfs_unlink,
10500         .link           = btrfs_link,
10501         .mkdir          = btrfs_mkdir,
10502         .rmdir          = btrfs_rmdir,
10503         .rename2        = btrfs_rename2,
10504         .symlink        = btrfs_symlink,
10505         .setattr        = btrfs_setattr,
10506         .mknod          = btrfs_mknod,
10507         .setxattr       = generic_setxattr,
10508         .getxattr       = generic_getxattr,
10509         .listxattr      = btrfs_listxattr,
10510         .removexattr    = generic_removexattr,
10511         .permission     = btrfs_permission,
10512         .get_acl        = btrfs_get_acl,
10513         .set_acl        = btrfs_set_acl,
10514         .update_time    = btrfs_update_time,
10515         .tmpfile        = btrfs_tmpfile,
10516 };
10517 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10518         .lookup         = btrfs_lookup,
10519         .permission     = btrfs_permission,
10520         .get_acl        = btrfs_get_acl,
10521         .set_acl        = btrfs_set_acl,
10522         .update_time    = btrfs_update_time,
10523 };
10524
10525 static const struct file_operations btrfs_dir_file_operations = {
10526         .llseek         = generic_file_llseek,
10527         .read           = generic_read_dir,
10528         .iterate        = btrfs_real_readdir,
10529         .unlocked_ioctl = btrfs_ioctl,
10530 #ifdef CONFIG_COMPAT
10531         .compat_ioctl   = btrfs_compat_ioctl,
10532 #endif
10533         .release        = btrfs_release_file,
10534         .fsync          = btrfs_sync_file,
10535 };
10536
10537 static const struct extent_io_ops btrfs_extent_io_ops = {
10538         .fill_delalloc = run_delalloc_range,
10539         .submit_bio_hook = btrfs_submit_bio_hook,
10540         .merge_bio_hook = btrfs_merge_bio_hook,
10541         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10542         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10543         .writepage_start_hook = btrfs_writepage_start_hook,
10544         .set_bit_hook = btrfs_set_bit_hook,
10545         .clear_bit_hook = btrfs_clear_bit_hook,
10546         .merge_extent_hook = btrfs_merge_extent_hook,
10547         .split_extent_hook = btrfs_split_extent_hook,
10548 };
10549
10550 /*
10551  * btrfs doesn't support the bmap operation because swapfiles
10552  * use bmap to make a mapping of extents in the file.  They assume
10553  * these extents won't change over the life of the file and they
10554  * use the bmap result to do IO directly to the drive.
10555  *
10556  * the btrfs bmap call would return logical addresses that aren't
10557  * suitable for IO and they also will change frequently as COW
10558  * operations happen.  So, swapfile + btrfs == corruption.
10559  *
10560  * For now we're avoiding this by dropping bmap.
10561  */
10562 static const struct address_space_operations btrfs_aops = {
10563         .readpage       = btrfs_readpage,
10564         .writepage      = btrfs_writepage,
10565         .writepages     = btrfs_writepages,
10566         .readpages      = btrfs_readpages,
10567         .direct_IO      = btrfs_direct_IO,
10568         .invalidatepage = btrfs_invalidatepage,
10569         .releasepage    = btrfs_releasepage,
10570         .set_page_dirty = btrfs_set_page_dirty,
10571         .error_remove_page = generic_error_remove_page,
10572 };
10573
10574 static const struct address_space_operations btrfs_symlink_aops = {
10575         .readpage       = btrfs_readpage,
10576         .writepage      = btrfs_writepage,
10577         .invalidatepage = btrfs_invalidatepage,
10578         .releasepage    = btrfs_releasepage,
10579 };
10580
10581 static const struct inode_operations btrfs_file_inode_operations = {
10582         .getattr        = btrfs_getattr,
10583         .setattr        = btrfs_setattr,
10584         .setxattr       = generic_setxattr,
10585         .getxattr       = generic_getxattr,
10586         .listxattr      = btrfs_listxattr,
10587         .removexattr    = generic_removexattr,
10588         .permission     = btrfs_permission,
10589         .fiemap         = btrfs_fiemap,
10590         .get_acl        = btrfs_get_acl,
10591         .set_acl        = btrfs_set_acl,
10592         .update_time    = btrfs_update_time,
10593 };
10594 static const struct inode_operations btrfs_special_inode_operations = {
10595         .getattr        = btrfs_getattr,
10596         .setattr        = btrfs_setattr,
10597         .permission     = btrfs_permission,
10598         .setxattr       = generic_setxattr,
10599         .getxattr       = generic_getxattr,
10600         .listxattr      = btrfs_listxattr,
10601         .removexattr    = generic_removexattr,
10602         .get_acl        = btrfs_get_acl,
10603         .set_acl        = btrfs_set_acl,
10604         .update_time    = btrfs_update_time,
10605 };
10606 static const struct inode_operations btrfs_symlink_inode_operations = {
10607         .readlink       = generic_readlink,
10608         .get_link       = page_get_link,
10609         .getattr        = btrfs_getattr,
10610         .setattr        = btrfs_setattr,
10611         .permission     = btrfs_permission,
10612         .setxattr       = generic_setxattr,
10613         .getxattr       = generic_getxattr,
10614         .listxattr      = btrfs_listxattr,
10615         .removexattr    = generic_removexattr,
10616         .update_time    = btrfs_update_time,
10617 };
10618
10619 const struct dentry_operations btrfs_dentry_operations = {
10620         .d_delete       = btrfs_dentry_delete,
10621         .d_release      = btrfs_dentry_release,
10622 };