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