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