fs/btrfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9 #include <linux/file.h>
  10 #include <linux/fs.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/init.h>
  15 #include <linux/string.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/writeback.h>
  18 #include <linux/compat.h>
  19 #include <linux/xattr.h>
  20 #include <linux/posix_acl.h>
  21 #include <linux/falloc.h>
  22 #include <linux/slab.h>
  23 #include <linux/ratelimit.h>
  24 #include <linux/btrfs.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/posix_acl_xattr.h>
  27 #include <linux/uio.h>
  28 #include <linux/magic.h>
  29 #include <linux/iversion.h>
  30 #include <asm/unaligned.h>
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "print-tree.h"
  36 #include "ordered-data.h"
  37 #include "xattr.h"
  38 #include "tree-log.h"
  39 #include "volumes.h"
  40 #include "compression.h"
  41 #include "locking.h"
  42 #include "free-space-cache.h"
  43 #include "inode-map.h"
  44 #include "backref.h"
  45 #include "props.h"
  46 #include "qgroup.h"
  47 #include "dedupe.h"
  48
  49 struct btrfs_iget_args {
  50         struct btrfs_key *location;
  51         struct btrfs_root *root;
  52 };
  53
  54 struct btrfs_dio_data {
  55         u64 reserve;
  56         u64 unsubmitted_oe_range_start;
  57         u64 unsubmitted_oe_range_end;
  58         int overwrite;
  59 };
  60
  61 static const struct inode_operations btrfs_dir_inode_operations;
  62 static const struct inode_operations btrfs_symlink_inode_operations;
  63 static const struct inode_operations btrfs_dir_ro_inode_operations;
  64 static const struct inode_operations btrfs_special_inode_operations;
  65 static const struct inode_operations btrfs_file_inode_operations;
  66 static const struct address_space_operations btrfs_aops;
  67 static const struct file_operations btrfs_dir_file_operations;
  68 static const struct extent_io_ops btrfs_extent_io_ops;
  69
  70 static struct kmem_cache *btrfs_inode_cachep;
  71 struct kmem_cache *btrfs_trans_handle_cachep;
  72 struct kmem_cache *btrfs_path_cachep;
  73 struct kmem_cache *btrfs_free_space_cachep;
  74
  75 #define S_SHIFT 12
  76 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  77         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  78         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  79         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  80         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  81         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  82         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  83         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  84 };
  85
  86 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  87 static int btrfs_truncate(struct inode *inode, bool skip_writeback);
  88 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  89 static noinline int cow_file_range(struct inode *inode,
  90                                    struct page *locked_page,
  91                                    u64 start, u64 end, u64 delalloc_end,
  92                                    int *page_started, unsigned long *nr_written,
  93                                    int unlock, struct btrfs_dedupe_hash *hash);
  94 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
  95                                        u64 orig_start, u64 block_start,
  96                                        u64 block_len, u64 orig_block_len,
  97                                        u64 ram_bytes, int compress_type,
  98                                        int type);
  99
 100 static void __endio_write_update_ordered(struct inode *inode,
 101                                          const u64 offset, const u64 bytes,
 102                                          const bool uptodate);
 103
 104 /*
 105  * Cleanup all submitted ordered extents in specified range to handle errors
 106  * from the fill_dellaloc() callback.
 107  *
 108  * NOTE: caller must ensure that when an error happens, it can not call
 109  * extent_clear_unlock_delalloc() to clear both the bits EXTENT_DO_ACCOUNTING
 110  * and EXTENT_DELALLOC simultaneously, because that causes the reserved metadata
 111  * to be released, which we want to happen only when finishing the ordered
 112  * extent (btrfs_finish_ordered_io()). Also note that the caller of the
 113  * fill_delalloc() callback already does proper cleanup for the first page of
 114  * the range, that is, it invokes the callback writepage_end_io_hook() for the
 115  * range of the first page.
 116  */
 117 static inline void btrfs_cleanup_ordered_extents(struct inode *inode,
 118                                                  const u64 offset,
 119                                                  const u64 bytes)
 120 {
 121         unsigned long index = offset >> PAGE_SHIFT;
 122         unsigned long end_index = (offset + bytes - 1) >> PAGE_SHIFT;
 123         struct page *page;
 124
 125         while (index <= end_index) {
 126                 page = find_get_page(inode->i_mapping, index);
 127                 index++;
 128                 if (!page)
 129                         continue;
 130                 ClearPagePrivate2(page);
 131                 put_page(page);
 132         }
 133         return __endio_write_update_ordered(inode, offset + PAGE_SIZE,
 134                                             bytes - PAGE_SIZE, false);
 135 }
 136
 137 static int btrfs_dirty_inode(struct inode *inode);
 138
 139 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 140 void btrfs_test_inode_set_ops(struct inode *inode)
 141 {
 142         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 143 }
 144 #endif
 145
 146 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 147                                      struct inode *inode,  struct inode *dir,
 148                                      const struct qstr *qstr)
 149 {
 150         int err;
 151
 152         err = btrfs_init_acl(trans, inode, dir);
 153         if (!err)
 154                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 155         return err;
 156 }
 157
 158 /*
 159  * this does all the hard work for inserting an inline extent into
 160  * the btree.  The caller should have done a btrfs_drop_extents so that
 161  * no overlapping inline items exist in the btree
 162  */
 163 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 164                                 struct btrfs_path *path, int extent_inserted,
 165                                 struct btrfs_root *root, struct inode *inode,
 166                                 u64 start, size_t size, size_t compressed_size,
 167                                 int compress_type,
 168                                 struct page **compressed_pages)
 169 {
 170         struct extent_buffer *leaf;
 171         struct page *page = NULL;
 172         char *kaddr;
 173         unsigned long ptr;
 174         struct btrfs_file_extent_item *ei;
 175         int ret;
 176         size_t cur_size = size;
 177         unsigned long offset;
 178
 179         if (compressed_size && compressed_pages)
 180                 cur_size = compressed_size;
 181
 182         inode_add_bytes(inode, size);
 183
 184         if (!extent_inserted) {
 185                 struct btrfs_key key;
 186                 size_t datasize;
 187
 188                 key.objectid = btrfs_ino(BTRFS_I(inode));
 189                 key.offset = start;
 190                 key.type = BTRFS_EXTENT_DATA_KEY;
 191
 192                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 193                 path->leave_spinning = 1;
 194                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 195                                               datasize);
 196                 if (ret)
 197                         goto fail;
 198         }
 199         leaf = path->nodes[0];
 200         ei = btrfs_item_ptr(leaf, path->slots[0],
 201                             struct btrfs_file_extent_item);
 202         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 203         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 204         btrfs_set_file_extent_encryption(leaf, ei, 0);
 205         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 206         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 207         ptr = btrfs_file_extent_inline_start(ei);
 208
 209         if (compress_type != BTRFS_COMPRESS_NONE) {
 210                 struct page *cpage;
 211                 int i = 0;
 212                 while (compressed_size > 0) {
 213                         cpage = compressed_pages[i];
 214                         cur_size = min_t(unsigned long, compressed_size,
 215                                        PAGE_SIZE);
 216
 217                         kaddr = kmap_atomic(cpage);
 218                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 219                         kunmap_atomic(kaddr);
 220
 221                         i++;
 222                         ptr += cur_size;
 223                         compressed_size -= cur_size;
 224                 }
 225                 btrfs_set_file_extent_compression(leaf, ei,
 226                                                   compress_type);
 227         } else {
 228                 page = find_get_page(inode->i_mapping,
 229                                      start >> PAGE_SHIFT);
 230                 btrfs_set_file_extent_compression(leaf, ei, 0);
 231                 kaddr = kmap_atomic(page);
 232                 offset = start & (PAGE_SIZE - 1);
 233                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 234                 kunmap_atomic(kaddr);
 235                 put_page(page);
 236         }
 237         btrfs_mark_buffer_dirty(leaf);
 238         btrfs_release_path(path);
 239
 240         /*
 241          * we're an inline extent, so nobody can
 242          * extend the file past i_size without locking
 243          * a page we already have locked.
 244          *
 245          * We must do any isize and inode updates
 246          * before we unlock the pages.  Otherwise we
 247          * could end up racing with unlink.
 248          */
 249         BTRFS_I(inode)->disk_i_size = inode->i_size;
 250         ret = btrfs_update_inode(trans, root, inode);
 251
 252 fail:
 253         return ret;
 254 }
 255
 256
 257 /*
 258  * conditionally insert an inline extent into the file.  This
 259  * does the checks required to make sure the data is small enough
 260  * to fit as an inline extent.
 261  */
 262 static noinline int cow_file_range_inline(struct inode *inode, u64 start,
 263                                           u64 end, size_t compressed_size,
 264                                           int compress_type,
 265                                           struct page **compressed_pages)
 266 {
 267         struct btrfs_root *root = BTRFS_I(inode)->root;
 268         struct btrfs_fs_info *fs_info = root->fs_info;
 269         struct btrfs_trans_handle *trans;
 270         u64 isize = i_size_read(inode);
 271         u64 actual_end = min(end + 1, isize);
 272         u64 inline_len = actual_end - start;
 273         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 274         u64 data_len = inline_len;
 275         int ret;
 276         struct btrfs_path *path;
 277         int extent_inserted = 0;
 278         u32 extent_item_size;
 279
 280         if (compressed_size)
 281                 data_len = compressed_size;
 282
 283         if (start > 0 ||
 284             actual_end > fs_info->sectorsize ||
 285             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 286             (!compressed_size &&
 287             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 288             end + 1 < isize ||
 289             data_len > fs_info->max_inline) {
 290                 return 1;
 291         }
 292
 293         path = btrfs_alloc_path();
 294         if (!path)
 295                 return -ENOMEM;
 296
 297         trans = btrfs_join_transaction(root);
 298         if (IS_ERR(trans)) {
 299                 btrfs_free_path(path);
 300                 return PTR_ERR(trans);
 301         }
 302         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
 303
 304         if (compressed_size && compressed_pages)
 305                 extent_item_size = btrfs_file_extent_calc_inline_size(
 306                    compressed_size);
 307         else
 308                 extent_item_size = btrfs_file_extent_calc_inline_size(
 309                     inline_len);
 310
 311         ret = __btrfs_drop_extents(trans, root, inode, path,
 312                                    start, aligned_end, NULL,
 313                                    1, 1, extent_item_size, &extent_inserted);
 314         if (ret) {
 315                 btrfs_abort_transaction(trans, ret);
 316                 goto out;
 317         }
 318
 319         if (isize > actual_end)
 320                 inline_len = min_t(u64, isize, actual_end);
 321         ret = insert_inline_extent(trans, path, extent_inserted,
 322                                    root, inode, start,
 323                                    inline_len, compressed_size,
 324                                    compress_type, compressed_pages);
 325         if (ret && ret != -ENOSPC) {
 326                 btrfs_abort_transaction(trans, ret);
 327                 goto out;
 328         } else if (ret == -ENOSPC) {
 329                 ret = 1;
 330                 goto out;
 331         }
 332
 333         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 334         btrfs_drop_extent_cache(BTRFS_I(inode), start, aligned_end - 1, 0);
 335 out:
 336         /*
 337          * Don't forget to free the reserved space, as for inlined extent
 338          * it won't count as data extent, free them directly here.
 339          * And at reserve time, it's always aligned to page size, so
 340          * just free one page here.
 341          */
 342         btrfs_qgroup_free_data(inode, NULL, 0, PAGE_SIZE);
 343         btrfs_free_path(path);
 344         btrfs_end_transaction(trans);
 345         return ret;
 346 }
 347
 348 struct async_extent {
 349         u64 start;
 350         u64 ram_size;
 351         u64 compressed_size;
 352         struct page **pages;
 353         unsigned long nr_pages;
 354         int compress_type;
 355         struct list_head list;
 356 };
 357
 358 struct async_cow {
 359         struct inode *inode;
 360         struct btrfs_root *root;
 361         struct page *locked_page;
 362         u64 start;
 363         u64 end;
 364         unsigned int write_flags;
 365         struct list_head extents;
 366         struct btrfs_work work;
 367 };
 368
 369 static noinline int add_async_extent(struct async_cow *cow,
 370                                      u64 start, u64 ram_size,
 371                                      u64 compressed_size,
 372                                      struct page **pages,
 373                                      unsigned long nr_pages,
 374                                      int compress_type)
 375 {
 376         struct async_extent *async_extent;
 377
 378         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 379         BUG_ON(!async_extent); /* -ENOMEM */
 380         async_extent->start = start;
 381         async_extent->ram_size = ram_size;
 382         async_extent->compressed_size = compressed_size;
 383         async_extent->pages = pages;
 384         async_extent->nr_pages = nr_pages;
 385         async_extent->compress_type = compress_type;
 386         list_add_tail(&async_extent->list, &cow->extents);
 387         return 0;
 388 }
 389
 390 static inline int inode_need_compress(struct inode *inode, u64 start, u64 end)
 391 {
 392         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 393
 394         /* force compress */
 395         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 396                 return 1;
 397         /* defrag ioctl */
 398         if (BTRFS_I(inode)->defrag_compress)
 399                 return 1;
 400         /* bad compression ratios */
 401         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 402                 return 0;
 403         if (btrfs_test_opt(fs_info, COMPRESS) ||
 404             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 405             BTRFS_I(inode)->prop_compress)
 406                 return btrfs_compress_heuristic(inode, start, end);
 407         return 0;
 408 }
 409
 410 static inline void inode_should_defrag(struct btrfs_inode *inode,
 411                 u64 start, u64 end, u64 num_bytes, u64 small_write)
 412 {
 413         /* If this is a small write inside eof, kick off a defrag */
 414         if (num_bytes < small_write &&
 415             (start > 0 || end + 1 < inode->disk_i_size))
 416                 btrfs_add_inode_defrag(NULL, inode);
 417 }
 418
 419 /*
 420  * we create compressed extents in two phases.  The first
 421  * phase compresses a range of pages that have already been
 422  * locked (both pages and state bits are locked).
 423  *
 424  * This is done inside an ordered work queue, and the compression
 425  * is spread across many cpus.  The actual IO submission is step
 426  * two, and the ordered work queue takes care of making sure that
 427  * happens in the same order things were put onto the queue by
 428  * writepages and friends.
 429  *
 430  * If this code finds it can't get good compression, it puts an
 431  * entry onto the work queue to write the uncompressed bytes.  This
 432  * makes sure that both compressed inodes and uncompressed inodes
 433  * are written in the same order that the flusher thread sent them
 434  * down.
 435  */
 436 static noinline void compress_file_range(struct inode *inode,
 437                                         struct page *locked_page,
 438                                         u64 start, u64 end,
 439                                         struct async_cow *async_cow,
 440                                         int *num_added)
 441 {
 442         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 443         u64 blocksize = fs_info->sectorsize;
 444         u64 actual_end;
 445         u64 isize = i_size_read(inode);
 446         int ret = 0;
 447         struct page **pages = NULL;
 448         unsigned long nr_pages;
 449         unsigned long total_compressed = 0;
 450         unsigned long total_in = 0;
 451         int i;
 452         int will_compress;
 453         int compress_type = fs_info->compress_type;
 454         int redirty = 0;
 455
 456         inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1,
 457                         SZ_16K);
 458
 459         actual_end = min_t(u64, isize, end + 1);
 460 again:
 461         will_compress = 0;
 462         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 463         BUILD_BUG_ON((BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0);
 464         nr_pages = min_t(unsigned long, nr_pages,
 465                         BTRFS_MAX_COMPRESSED / PAGE_SIZE);
 466
 467         /*
 468          * we don't want to send crud past the end of i_size through
 469          * compression, that's just a waste of CPU time.  So, if the
 470          * end of the file is before the start of our current
 471          * requested range of bytes, we bail out to the uncompressed
 472          * cleanup code that can deal with all of this.
 473          *
 474          * It isn't really the fastest way to fix things, but this is a
 475          * very uncommon corner.
 476          */
 477         if (actual_end <= start)
 478                 goto cleanup_and_bail_uncompressed;
 479
 480         total_compressed = actual_end - start;
 481
 482         /*
 483          * skip compression for a small file range(<=blocksize) that
 484          * isn't an inline extent, since it doesn't save disk space at all.
 485          */
 486         if (total_compressed <= blocksize &&
 487            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 488                 goto cleanup_and_bail_uncompressed;
 489
 490         total_compressed = min_t(unsigned long, total_compressed,
 491                         BTRFS_MAX_UNCOMPRESSED);
 492         total_in = 0;
 493         ret = 0;
 494
 495         /*
 496          * we do compression for mount -o compress and when the
 497          * inode has not been flagged as nocompress.  This flag can
 498          * change at any time if we discover bad compression ratios.
 499          */
 500         if (inode_need_compress(inode, start, end)) {
 501                 WARN_ON(pages);
 502                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 503                 if (!pages) {
 504                         /* just bail out to the uncompressed code */
 505                         nr_pages = 0;
 506                         goto cont;
 507                 }
 508
 509                 if (BTRFS_I(inode)->defrag_compress)
 510                         compress_type = BTRFS_I(inode)->defrag_compress;
 511                 else if (BTRFS_I(inode)->prop_compress)
 512                         compress_type = BTRFS_I(inode)->prop_compress;
 513
 514                 /*
 515                  * we need to call clear_page_dirty_for_io on each
 516                  * page in the range.  Otherwise applications with the file
 517                  * mmap'd can wander in and change the page contents while
 518                  * we are compressing them.
 519                  *
 520                  * If the compression fails for any reason, we set the pages
 521                  * dirty again later on.
 522                  *
 523                  * Note that the remaining part is redirtied, the start pointer
 524                  * has moved, the end is the original one.
 525                  */
 526                 if (!redirty) {
 527                         extent_range_clear_dirty_for_io(inode, start, end);
 528                         redirty = 1;
 529                 }
 530
 531                 /* Compression level is applied here and only here */
 532                 ret = btrfs_compress_pages(
 533                         compress_type | (fs_info->compress_level << 4),
 534                                            inode->i_mapping, start,
 535                                            pages,
 536                                            &nr_pages,
 537                                            &total_in,
 538                                            &total_compressed);
 539
 540                 if (!ret) {
 541                         unsigned long offset = total_compressed &
 542                                 (PAGE_SIZE - 1);
 543                         struct page *page = pages[nr_pages - 1];
 544                         char *kaddr;
 545
 546                         /* zero the tail end of the last page, we might be
 547                          * sending it down to disk
 548                          */
 549                         if (offset) {
 550                                 kaddr = kmap_atomic(page);
 551                                 memset(kaddr + offset, 0,
 552                                        PAGE_SIZE - offset);
 553                                 kunmap_atomic(kaddr);
 554                         }
 555                         will_compress = 1;
 556                 }
 557         }
 558 cont:
 559         if (start == 0) {
 560                 /* lets try to make an inline extent */
 561                 if (ret || total_in < actual_end) {
 562                         /* we didn't compress the entire range, try
 563                          * to make an uncompressed inline extent.
 564                          */
 565                         ret = cow_file_range_inline(inode, start, end, 0,
 566                                                     BTRFS_COMPRESS_NONE, NULL);
 567                 } else {
 568                         /* try making a compressed inline extent */
 569                         ret = cow_file_range_inline(inode, start, end,
 570                                                     total_compressed,
 571                                                     compress_type, pages);
 572                 }
 573                 if (ret <= 0) {
 574                         unsigned long clear_flags = EXTENT_DELALLOC |
 575                                 EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 576                                 EXTENT_DO_ACCOUNTING;
 577                         unsigned long page_error_op;
 578
 579                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 580
 581                         /*
 582                          * inline extent creation worked or returned error,
 583                          * we don't need to create any more async work items.
 584                          * Unlock and free up our temp pages.
 585                          *
 586                          * We use DO_ACCOUNTING here because we need the
 587                          * delalloc_release_metadata to be done _after_ we drop
 588                          * our outstanding extent for clearing delalloc for this
 589                          * range.
 590                          */
 591                         extent_clear_unlock_delalloc(inode, start, end, end,
 592                                                      NULL, clear_flags,
 593                                                      PAGE_UNLOCK |
 594                                                      PAGE_CLEAR_DIRTY |
 595                                                      PAGE_SET_WRITEBACK |
 596                                                      page_error_op |
 597                                                      PAGE_END_WRITEBACK);
 598                         goto free_pages_out;
 599                 }
 600         }
 601
 602         if (will_compress) {
 603                 /*
 604                  * we aren't doing an inline extent round the compressed size
 605                  * up to a block size boundary so the allocator does sane
 606                  * things
 607                  */
 608                 total_compressed = ALIGN(total_compressed, blocksize);
 609
 610                 /*
 611                  * one last check to make sure the compression is really a
 612                  * win, compare the page count read with the blocks on disk,
 613                  * compression must free at least one sector size
 614                  */
 615                 total_in = ALIGN(total_in, PAGE_SIZE);
 616                 if (total_compressed + blocksize <= total_in) {
 617                         *num_added += 1;
 618
 619                         /*
 620                          * The async work queues will take care of doing actual
 621                          * allocation on disk for these compressed pages, and
 622                          * will submit them to the elevator.
 623                          */
 624                         add_async_extent(async_cow, start, total_in,
 625                                         total_compressed, pages, nr_pages,
 626                                         compress_type);
 627
 628                         if (start + total_in < end) {
 629                                 start += total_in;
 630                                 pages = NULL;
 631                                 cond_resched();
 632                                 goto again;
 633                         }
 634                         return;
 635                 }
 636         }
 637         if (pages) {
 638                 /*
 639                  * the compression code ran but failed to make things smaller,
 640                  * free any pages it allocated and our page pointer array
 641                  */
 642                 for (i = 0; i < nr_pages; i++) {
 643                         WARN_ON(pages[i]->mapping);
 644                         put_page(pages[i]);
 645                 }
 646                 kfree(pages);
 647                 pages = NULL;
 648                 total_compressed = 0;
 649                 nr_pages = 0;
 650
 651                 /* flag the file so we don't compress in the future */
 652                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 653                     !(BTRFS_I(inode)->prop_compress)) {
 654                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 655                 }
 656         }
 657 cleanup_and_bail_uncompressed:
 658         /*
 659          * No compression, but we still need to write the pages in the file
 660          * we've been given so far.  redirty the locked page if it corresponds
 661          * to our extent and set things up for the async work queue to run
 662          * cow_file_range to do the normal delalloc dance.
 663          */
 664         if (page_offset(locked_page) >= start &&
 665             page_offset(locked_page) <= end)
 666                 __set_page_dirty_nobuffers(locked_page);
 667                 /* unlocked later on in the async handlers */
 668
 669         if (redirty)
 670                 extent_range_redirty_for_io(inode, start, end);
 671         add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0,
 672                          BTRFS_COMPRESS_NONE);
 673         *num_added += 1;
 674
 675         return;
 676
 677 free_pages_out:
 678         for (i = 0; i < nr_pages; i++) {
 679                 WARN_ON(pages[i]->mapping);
 680                 put_page(pages[i]);
 681         }
 682         kfree(pages);
 683 }
 684
 685 static void free_async_extent_pages(struct async_extent *async_extent)
 686 {
 687         int i;
 688
 689         if (!async_extent->pages)
 690                 return;
 691
 692         for (i = 0; i < async_extent->nr_pages; i++) {
 693                 WARN_ON(async_extent->pages[i]->mapping);
 694                 put_page(async_extent->pages[i]);
 695         }
 696         kfree(async_extent->pages);
 697         async_extent->nr_pages = 0;
 698         async_extent->pages = NULL;
 699 }
 700
 701 /*
 702  * phase two of compressed writeback.  This is the ordered portion
 703  * of the code, which only gets called in the order the work was
 704  * queued.  We walk all the async extents created by compress_file_range
 705  * and send them down to the disk.
 706  */
 707 static noinline void submit_compressed_extents(struct inode *inode,
 708                                               struct async_cow *async_cow)
 709 {
 710         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 711         struct async_extent *async_extent;
 712         u64 alloc_hint = 0;
 713         struct btrfs_key ins;
 714         struct extent_map *em;
 715         struct btrfs_root *root = BTRFS_I(inode)->root;
 716         struct extent_io_tree *io_tree;
 717         int ret = 0;
 718
 719 again:
 720         while (!list_empty(&async_cow->extents)) {
 721                 async_extent = list_entry(async_cow->extents.next,
 722                                           struct async_extent, list);
 723                 list_del(&async_extent->list);
 724
 725                 io_tree = &BTRFS_I(inode)->io_tree;
 726
 727 retry:
 728                 /* did the compression code fall back to uncompressed IO? */
 729                 if (!async_extent->pages) {
 730                         int page_started = 0;
 731                         unsigned long nr_written = 0;
 732
 733                         lock_extent(io_tree, async_extent->start,
 734                                          async_extent->start +
 735                                          async_extent->ram_size - 1);
 736
 737                         /* allocate blocks */
 738                         ret = cow_file_range(inode, async_cow->locked_page,
 739                                              async_extent->start,
 740                                              async_extent->start +
 741                                              async_extent->ram_size - 1,
 742                                              async_extent->start +
 743                                              async_extent->ram_size - 1,
 744                                              &page_started, &nr_written, 0,
 745                                              NULL);
 746
 747                         /* JDM XXX */
 748
 749                         /*
 750                          * if page_started, cow_file_range inserted an
 751                          * inline extent and took care of all the unlocking
 752                          * and IO for us.  Otherwise, we need to submit
 753                          * all those pages down to the drive.
 754                          */
 755                         if (!page_started && !ret)
 756                                 extent_write_locked_range(inode,
 757                                                   async_extent->start,
 758                                                   async_extent->start +
 759                                                   async_extent->ram_size - 1,
 760                                                   WB_SYNC_ALL);
 761                         else if (ret)
 762                                 unlock_page(async_cow->locked_page);
 763                         kfree(async_extent);
 764                         cond_resched();
 765                         continue;
 766                 }
 767
 768                 lock_extent(io_tree, async_extent->start,
 769                             async_extent->start + async_extent->ram_size - 1);
 770
 771                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 772                                            async_extent->compressed_size,
 773                                            async_extent->compressed_size,
 774                                            0, alloc_hint, &ins, 1, 1);
 775                 if (ret) {
 776                         free_async_extent_pages(async_extent);
 777
 778                         if (ret == -ENOSPC) {
 779                                 unlock_extent(io_tree, async_extent->start,
 780                                               async_extent->start +
 781                                               async_extent->ram_size - 1);
 782
 783                                 /*
 784                                  * we need to redirty the pages if we decide to
 785                                  * fallback to uncompressed IO, otherwise we
 786                                  * will not submit these pages down to lower
 787                                  * layers.
 788                                  */
 789                                 extent_range_redirty_for_io(inode,
 790                                                 async_extent->start,
 791                                                 async_extent->start +
 792                                                 async_extent->ram_size - 1);
 793
 794                                 goto retry;
 795                         }
 796                         goto out_free;
 797                 }
 798                 /*
 799                  * here we're doing allocation and writeback of the
 800                  * compressed pages
 801                  */
 802                 em = create_io_em(inode, async_extent->start,
 803                                   async_extent->ram_size, /* len */
 804                                   async_extent->start, /* orig_start */
 805                                   ins.objectid, /* block_start */
 806                                   ins.offset, /* block_len */
 807                                   ins.offset, /* orig_block_len */
 808                                   async_extent->ram_size, /* ram_bytes */
 809                                   async_extent->compress_type,
 810                                   BTRFS_ORDERED_COMPRESSED);
 811                 if (IS_ERR(em))
 812                         /* ret value is not necessary due to void function */
 813                         goto out_free_reserve;
 814                 free_extent_map(em);
 815
 816                 ret = btrfs_add_ordered_extent_compress(inode,
 817                                                 async_extent->start,
 818                                                 ins.objectid,
 819                                                 async_extent->ram_size,
 820                                                 ins.offset,
 821                                                 BTRFS_ORDERED_COMPRESSED,
 822                                                 async_extent->compress_type);
 823                 if (ret) {
 824                         btrfs_drop_extent_cache(BTRFS_I(inode),
 825                                                 async_extent->start,
 826                                                 async_extent->start +
 827                                                 async_extent->ram_size - 1, 0);
 828                         goto out_free_reserve;
 829                 }
 830                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 831
 832                 /*
 833                  * clear dirty, set writeback and unlock the pages.
 834                  */
 835                 extent_clear_unlock_delalloc(inode, async_extent->start,
 836                                 async_extent->start +
 837                                 async_extent->ram_size - 1,
 838                                 async_extent->start +
 839                                 async_extent->ram_size - 1,
 840                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 841                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 842                                 PAGE_SET_WRITEBACK);
 843                 if (btrfs_submit_compressed_write(inode,
 844                                     async_extent->start,
 845                                     async_extent->ram_size,
 846                                     ins.objectid,
 847                                     ins.offset, async_extent->pages,
 848                                     async_extent->nr_pages,
 849                                     async_cow->write_flags)) {
 850                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 851                         struct page *p = async_extent->pages[0];
 852                         const u64 start = async_extent->start;
 853                         const u64 end = start + async_extent->ram_size - 1;
 854
 855                         p->mapping = inode->i_mapping;
 856                         tree->ops->writepage_end_io_hook(p, start, end,
 857                                                          NULL, 0);
 858                         p->mapping = NULL;
 859                         extent_clear_unlock_delalloc(inode, start, end, end,
 860                                                      NULL, 0,
 861                                                      PAGE_END_WRITEBACK |
 862                                                      PAGE_SET_ERROR);
 863                         free_async_extent_pages(async_extent);
 864                 }
 865                 alloc_hint = ins.objectid + ins.offset;
 866                 kfree(async_extent);
 867                 cond_resched();
 868         }
 869         return;
 870 out_free_reserve:
 871         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 872         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 873 out_free:
 874         extent_clear_unlock_delalloc(inode, async_extent->start,
 875                                      async_extent->start +
 876                                      async_extent->ram_size - 1,
 877                                      async_extent->start +
 878                                      async_extent->ram_size - 1,
 879                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 880                                      EXTENT_DELALLOC_NEW |
 881                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 882                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 883                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 884                                      PAGE_SET_ERROR);
 885         free_async_extent_pages(async_extent);
 886         kfree(async_extent);
 887         goto again;
 888 }
 889
 890 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 891                                       u64 num_bytes)
 892 {
 893         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 894         struct extent_map *em;
 895         u64 alloc_hint = 0;
 896
 897         read_lock(&em_tree->lock);
 898         em = search_extent_mapping(em_tree, start, num_bytes);
 899         if (em) {
 900                 /*
 901                  * if block start isn't an actual block number then find the
 902                  * first block in this inode and use that as a hint.  If that
 903                  * block is also bogus then just don't worry about it.
 904                  */
 905                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 906                         free_extent_map(em);
 907                         em = search_extent_mapping(em_tree, 0, 0);
 908                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 909                                 alloc_hint = em->block_start;
 910                         if (em)
 911                                 free_extent_map(em);
 912                 } else {
 913                         alloc_hint = em->block_start;
 914                         free_extent_map(em);
 915                 }
 916         }
 917         read_unlock(&em_tree->lock);
 918
 919         return alloc_hint;
 920 }
 921
 922 /*
 923  * when extent_io.c finds a delayed allocation range in the file,
 924  * the call backs end up in this code.  The basic idea is to
 925  * allocate extents on disk for the range, and create ordered data structs
 926  * in ram to track those extents.
 927  *
 928  * locked_page is the page that writepage had locked already.  We use
 929  * it to make sure we don't do extra locks or unlocks.
 930  *
 931  * *page_started is set to one if we unlock locked_page and do everything
 932  * required to start IO on it.  It may be clean and already done with
 933  * IO when we return.
 934  */
 935 static noinline int cow_file_range(struct inode *inode,
 936                                    struct page *locked_page,
 937                                    u64 start, u64 end, u64 delalloc_end,
 938                                    int *page_started, unsigned long *nr_written,
 939                                    int unlock, struct btrfs_dedupe_hash *hash)
 940 {
 941         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 942         struct btrfs_root *root = BTRFS_I(inode)->root;
 943         u64 alloc_hint = 0;
 944         u64 num_bytes;
 945         unsigned long ram_size;
 946         u64 cur_alloc_size = 0;
 947         u64 blocksize = fs_info->sectorsize;
 948         struct btrfs_key ins;
 949         struct extent_map *em;
 950         unsigned clear_bits;
 951         unsigned long page_ops;
 952         bool extent_reserved = false;
 953         int ret = 0;
 954
 955         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 956                 WARN_ON_ONCE(1);
 957                 ret = -EINVAL;
 958                 goto out_unlock;
 959         }
 960
 961         num_bytes = ALIGN(end - start + 1, blocksize);
 962         num_bytes = max(blocksize,  num_bytes);
 963         ASSERT(num_bytes <= btrfs_super_total_bytes(fs_info->super_copy));
 964
 965         inode_should_defrag(BTRFS_I(inode), start, end, num_bytes, SZ_64K);
 966
 967         if (start == 0) {
 968                 /* lets try to make an inline extent */
 969                 ret = cow_file_range_inline(inode, start, end, 0,
 970                                             BTRFS_COMPRESS_NONE, NULL);
 971                 if (ret == 0) {
 972                         /*
 973                          * We use DO_ACCOUNTING here because we need the
 974                          * delalloc_release_metadata to be run _after_ we drop
 975                          * our outstanding extent for clearing delalloc for this
 976                          * range.
 977                          */
 978                         extent_clear_unlock_delalloc(inode, start, end,
 979                                      delalloc_end, NULL,
 980                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 981                                      EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 982                                      EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
 983                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 984                                      PAGE_END_WRITEBACK);
 985                         *nr_written = *nr_written +
 986                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 987                         *page_started = 1;
 988                         goto out;
 989                 } else if (ret < 0) {
 990                         goto out_unlock;
 991                 }
 992         }
 993
 994         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 995         btrfs_drop_extent_cache(BTRFS_I(inode), start,
 996                         start + num_bytes - 1, 0);
 997
 998         while (num_bytes > 0) {
 999                 cur_alloc_size = num_bytes;
1000                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
1001                                            fs_info->sectorsize, 0, alloc_hint,
1002                                            &ins, 1, 1);
1003                 if (ret < 0)
1004                         goto out_unlock;
1005                 cur_alloc_size = ins.offset;
1006                 extent_reserved = true;
1007
1008                 ram_size = ins.offset;
1009                 em = create_io_em(inode, start, ins.offset, /* len */
1010                                   start, /* orig_start */
1011                                   ins.objectid, /* block_start */
1012                                   ins.offset, /* block_len */
1013                                   ins.offset, /* orig_block_len */
1014                                   ram_size, /* ram_bytes */
1015                                   BTRFS_COMPRESS_NONE, /* compress_type */
1016                                   BTRFS_ORDERED_REGULAR /* type */);
1017                 if (IS_ERR(em)) {
1018                         ret = PTR_ERR(em);
1019                         goto out_reserve;
1020                 }
1021                 free_extent_map(em);
1022
1023                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1024                                                ram_size, cur_alloc_size, 0);
1025                 if (ret)
1026                         goto out_drop_extent_cache;
1027
1028                 if (root->root_key.objectid ==
1029                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1030                         ret = btrfs_reloc_clone_csums(inode, start,
1031                                                       cur_alloc_size);
1032                         /*
1033                          * Only drop cache here, and process as normal.
1034                          *
1035                          * We must not allow extent_clear_unlock_delalloc()
1036                          * at out_unlock label to free meta of this ordered
1037                          * extent, as its meta should be freed by
1038                          * btrfs_finish_ordered_io().
1039                          *
1040                          * So we must continue until @start is increased to
1041                          * skip current ordered extent.
1042                          */
1043                         if (ret)
1044                                 btrfs_drop_extent_cache(BTRFS_I(inode), start,
1045                                                 start + ram_size - 1, 0);
1046                 }
1047
1048                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1049
1050                 /* we're not doing compressed IO, don't unlock the first
1051                  * page (which the caller expects to stay locked), don't
1052                  * clear any dirty bits and don't set any writeback bits
1053                  *
1054                  * Do set the Private2 bit so we know this page was properly
1055                  * setup for writepage
1056                  */
1057                 page_ops = unlock ? PAGE_UNLOCK : 0;
1058                 page_ops |= PAGE_SET_PRIVATE2;
1059
1060                 extent_clear_unlock_delalloc(inode, start,
1061                                              start + ram_size - 1,
1062                                              delalloc_end, locked_page,
1063                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1064                                              page_ops);
1065                 if (num_bytes < cur_alloc_size)
1066                         num_bytes = 0;
1067                 else
1068                         num_bytes -= cur_alloc_size;
1069                 alloc_hint = ins.objectid + ins.offset;
1070                 start += cur_alloc_size;
1071                 extent_reserved = false;
1072
1073                 /*
1074                  * btrfs_reloc_clone_csums() error, since start is increased
1075                  * extent_clear_unlock_delalloc() at out_unlock label won't
1076                  * free metadata of current ordered extent, we're OK to exit.
1077                  */
1078                 if (ret)
1079                         goto out_unlock;
1080         }
1081 out:
1082         return ret;
1083
1084 out_drop_extent_cache:
1085         btrfs_drop_extent_cache(BTRFS_I(inode), start, start + ram_size - 1, 0);
1086 out_reserve:
1087         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1088         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1089 out_unlock:
1090         clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
1091                 EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
1092         page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
1093                 PAGE_END_WRITEBACK;
1094         /*
1095          * If we reserved an extent for our delalloc range (or a subrange) and
1096          * failed to create the respective ordered extent, then it means that
1097          * when we reserved the extent we decremented the extent's size from
1098          * the data space_info's bytes_may_use counter and incremented the
1099          * space_info's bytes_reserved counter by the same amount. We must make
1100          * sure extent_clear_unlock_delalloc() does not try to decrement again
1101          * the data space_info's bytes_may_use counter, therefore we do not pass
1102          * it the flag EXTENT_CLEAR_DATA_RESV.
1103          */
1104         if (extent_reserved) {
1105                 extent_clear_unlock_delalloc(inode, start,
1106                                              start + cur_alloc_size,
1107                                              start + cur_alloc_size,
1108                                              locked_page,
1109                                              clear_bits,
1110                                              page_ops);
1111                 start += cur_alloc_size;
1112                 if (start >= end)
1113                         goto out;
1114         }
1115         extent_clear_unlock_delalloc(inode, start, end, delalloc_end,
1116                                      locked_page,
1117                                      clear_bits | EXTENT_CLEAR_DATA_RESV,
1118                                      page_ops);
1119         goto out;
1120 }
1121
1122 /*
1123  * work queue call back to started compression on a file and pages
1124  */
1125 static noinline void async_cow_start(struct btrfs_work *work)
1126 {
1127         struct async_cow *async_cow;
1128         int num_added = 0;
1129         async_cow = container_of(work, struct async_cow, work);
1130
1131         compress_file_range(async_cow->inode, async_cow->locked_page,
1132                             async_cow->start, async_cow->end, async_cow,
1133                             &num_added);
1134         if (num_added == 0) {
1135                 btrfs_add_delayed_iput(async_cow->inode);
1136                 async_cow->inode = NULL;
1137         }
1138 }
1139
1140 /*
1141  * work queue call back to submit previously compressed pages
1142  */
1143 static noinline void async_cow_submit(struct btrfs_work *work)
1144 {
1145         struct btrfs_fs_info *fs_info;
1146         struct async_cow *async_cow;
1147         struct btrfs_root *root;
1148         unsigned long nr_pages;
1149
1150         async_cow = container_of(work, struct async_cow, work);
1151
1152         root = async_cow->root;
1153         fs_info = root->fs_info;
1154         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1155                 PAGE_SHIFT;
1156
1157         /* atomic_sub_return implies a barrier */
1158         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1159             5 * SZ_1M)
1160                 cond_wake_up_nomb(&fs_info->async_submit_wait);
1161
1162         if (async_cow->inode)
1163                 submit_compressed_extents(async_cow->inode, async_cow);
1164 }
1165
1166 static noinline void async_cow_free(struct btrfs_work *work)
1167 {
1168         struct async_cow *async_cow;
1169         async_cow = container_of(work, struct async_cow, work);
1170         if (async_cow->inode)
1171                 btrfs_add_delayed_iput(async_cow->inode);
1172         kfree(async_cow);
1173 }
1174
1175 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1176                                 u64 start, u64 end, int *page_started,
1177                                 unsigned long *nr_written,
1178                                 unsigned int write_flags)
1179 {
1180         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1181         struct async_cow *async_cow;
1182         struct btrfs_root *root = BTRFS_I(inode)->root;
1183         unsigned long nr_pages;
1184         u64 cur_end;
1185
1186         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1187                          1, 0, NULL);
1188         while (start < end) {
1189                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1190                 BUG_ON(!async_cow); /* -ENOMEM */
1191                 async_cow->inode = igrab(inode);
1192                 async_cow->root = root;
1193                 async_cow->locked_page = locked_page;
1194                 async_cow->start = start;
1195                 async_cow->write_flags = write_flags;
1196
1197                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1198                     !btrfs_test_opt(fs_info, FORCE_COMPRESS))
1199                         cur_end = end;
1200                 else
1201                         cur_end = min(end, start + SZ_512K - 1);
1202
1203                 async_cow->end = cur_end;
1204                 INIT_LIST_HEAD(&async_cow->extents);
1205
1206                 btrfs_init_work(&async_cow->work,
1207                                 btrfs_delalloc_helper,
1208                                 async_cow_start, async_cow_submit,
1209                                 async_cow_free);
1210
1211                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1212                         PAGE_SHIFT;
1213                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1214
1215                 btrfs_queue_work(fs_info->delalloc_workers, &async_cow->work);
1216
1217                 *nr_written += nr_pages;
1218                 start = cur_end + 1;
1219         }
1220         *page_started = 1;
1221         return 0;
1222 }
1223
1224 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1225                                         u64 bytenr, u64 num_bytes)
1226 {
1227         int ret;
1228         struct btrfs_ordered_sum *sums;
1229         LIST_HEAD(list);
1230
1231         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1232                                        bytenr + num_bytes - 1, &list, 0);
1233         if (ret == 0 && list_empty(&list))
1234                 return 0;
1235
1236         while (!list_empty(&list)) {
1237                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1238                 list_del(&sums->list);
1239                 kfree(sums);
1240         }
1241         if (ret < 0)
1242                 return ret;
1243         return 1;
1244 }
1245
1246 /*
1247  * when nowcow writeback call back.  This checks for snapshots or COW copies
1248  * of the extents that exist in the file, and COWs the file as required.
1249  *
1250  * If no cow copies or snapshots exist, we write directly to the existing
1251  * blocks on disk
1252  */
1253 static noinline int run_delalloc_nocow(struct inode *inode,
1254                                        struct page *locked_page,
1255                               u64 start, u64 end, int *page_started, int force,
1256                               unsigned long *nr_written)
1257 {
1258         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1259         struct btrfs_root *root = BTRFS_I(inode)->root;
1260         struct extent_buffer *leaf;
1261         struct btrfs_path *path;
1262         struct btrfs_file_extent_item *fi;
1263         struct btrfs_key found_key;
1264         struct extent_map *em;
1265         u64 cow_start;
1266         u64 cur_offset;
1267         u64 extent_end;
1268         u64 extent_offset;
1269         u64 disk_bytenr;
1270         u64 num_bytes;
1271         u64 disk_num_bytes;
1272         u64 ram_bytes;
1273         int extent_type;
1274         int ret;
1275         int type;
1276         int nocow;
1277         int check_prev = 1;
1278         bool nolock;
1279         u64 ino = btrfs_ino(BTRFS_I(inode));
1280
1281         path = btrfs_alloc_path();
1282         if (!path) {
1283                 extent_clear_unlock_delalloc(inode, start, end, end,
1284                                              locked_page,
1285                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1286                                              EXTENT_DO_ACCOUNTING |
1287                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1288                                              PAGE_CLEAR_DIRTY |
1289                                              PAGE_SET_WRITEBACK |
1290                                              PAGE_END_WRITEBACK);
1291                 return -ENOMEM;
1292         }
1293
1294         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
1295
1296         cow_start = (u64)-1;
1297         cur_offset = start;
1298         while (1) {
1299                 ret = btrfs_lookup_file_extent(NULL, root, path, ino,
1300                                                cur_offset, 0);
1301                 if (ret < 0)
1302                         goto error;
1303                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1304                         leaf = path->nodes[0];
1305                         btrfs_item_key_to_cpu(leaf, &found_key,
1306                                               path->slots[0] - 1);
1307                         if (found_key.objectid == ino &&
1308                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1309                                 path->slots[0]--;
1310                 }
1311                 check_prev = 0;
1312 next_slot:
1313                 leaf = path->nodes[0];
1314                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1315                         ret = btrfs_next_leaf(root, path);
1316                         if (ret < 0) {
1317                                 if (cow_start != (u64)-1)
1318                                         cur_offset = cow_start;
1319                                 goto error;
1320                         }
1321                         if (ret > 0)
1322                                 break;
1323                         leaf = path->nodes[0];
1324                 }
1325
1326                 nocow = 0;
1327                 disk_bytenr = 0;
1328                 num_bytes = 0;
1329                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1330
1331                 if (found_key.objectid > ino)
1332                         break;
1333                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1334                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1335                         path->slots[0]++;
1336                         goto next_slot;
1337                 }
1338                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1339                     found_key.offset > end)
1340                         break;
1341
1342                 if (found_key.offset > cur_offset) {
1343                         extent_end = found_key.offset;
1344                         extent_type = 0;
1345                         goto out_check;
1346                 }
1347
1348                 fi = btrfs_item_ptr(leaf, path->slots[0],
1349                                     struct btrfs_file_extent_item);
1350                 extent_type = btrfs_file_extent_type(leaf, fi);
1351
1352                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1353                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1354                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1355                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1356                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1357                         extent_end = found_key.offset +
1358                                 btrfs_file_extent_num_bytes(leaf, fi);
1359                         disk_num_bytes =
1360                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1361                         if (extent_end <= start) {
1362                                 path->slots[0]++;
1363                                 goto next_slot;
1364                         }
1365                         if (disk_bytenr == 0)
1366                                 goto out_check;
1367                         if (btrfs_file_extent_compression(leaf, fi) ||
1368                             btrfs_file_extent_encryption(leaf, fi) ||
1369                             btrfs_file_extent_other_encoding(leaf, fi))
1370                                 goto out_check;
1371                         /*
1372                          * Do the same check as in btrfs_cross_ref_exist but
1373                          * without the unnecessary search.
1374                          */
1375                         if (btrfs_file_extent_generation(leaf, fi) <=
1376                             btrfs_root_last_snapshot(&root->root_item))
1377                                 goto out_check;
1378                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1379                                 goto out_check;
1380                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1381                                 goto out_check;
1382                         ret = btrfs_cross_ref_exist(root, ino,
1383                                                     found_key.offset -
1384                                                     extent_offset, disk_bytenr);
1385                         if (ret) {
1386                                 /*
1387                                  * ret could be -EIO if the above fails to read
1388                                  * metadata.
1389                                  */
1390                                 if (ret < 0) {
1391                                         if (cow_start != (u64)-1)
1392                                                 cur_offset = cow_start;
1393                                         goto error;
1394                                 }
1395
1396                                 WARN_ON_ONCE(nolock);
1397                                 goto out_check;
1398                         }
1399                         disk_bytenr += extent_offset;
1400                         disk_bytenr += cur_offset - found_key.offset;
1401                         num_bytes = min(end + 1, extent_end) - cur_offset;
1402                         /*
1403                          * if there are pending snapshots for this root,
1404                          * we fall into common COW way.
1405                          */
1406                         if (!nolock && atomic_read(&root->snapshot_force_cow))
1407                                 goto out_check;
1408                         /*
1409                          * force cow if csum exists in the range.
1410                          * this ensure that csum for a given extent are
1411                          * either valid or do not exist.
1412                          */
1413                         ret = csum_exist_in_range(fs_info, disk_bytenr,
1414                                                   num_bytes);
1415                         if (ret) {
1416                                 /*
1417                                  * ret could be -EIO if the above fails to read
1418                                  * metadata.
1419                                  */
1420                                 if (ret < 0) {
1421                                         if (cow_start != (u64)-1)
1422                                                 cur_offset = cow_start;
1423                                         goto error;
1424                                 }
1425                                 WARN_ON_ONCE(nolock);
1426                                 goto out_check;
1427                         }
1428                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
1429                                 goto out_check;
1430                         nocow = 1;
1431                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1432                         extent_end = found_key.offset +
1433                                 btrfs_file_extent_ram_bytes(leaf, fi);
1434                         extent_end = ALIGN(extent_end,
1435                                            fs_info->sectorsize);
1436                 } else {
1437                         BUG_ON(1);
1438                 }
1439 out_check:
1440                 if (extent_end <= start) {
1441                         path->slots[0]++;
1442                         if (nocow)
1443                                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1444                         goto next_slot;
1445                 }
1446                 if (!nocow) {
1447                         if (cow_start == (u64)-1)
1448                                 cow_start = cur_offset;
1449                         cur_offset = extent_end;
1450                         if (cur_offset > end)
1451                                 break;
1452                         path->slots[0]++;
1453                         goto next_slot;
1454                 }
1455
1456                 btrfs_release_path(path);
1457                 if (cow_start != (u64)-1) {
1458                         ret = cow_file_range(inode, locked_page,
1459                                              cow_start, found_key.offset - 1,
1460                                              end, page_started, nr_written, 1,
1461                                              NULL);
1462                         if (ret) {
1463                                 if (nocow)
1464                                         btrfs_dec_nocow_writers(fs_info,
1465                                                                 disk_bytenr);
1466                                 goto error;
1467                         }
1468                         cow_start = (u64)-1;
1469                 }
1470
1471                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1472                         u64 orig_start = found_key.offset - extent_offset;
1473
1474                         em = create_io_em(inode, cur_offset, num_bytes,
1475                                           orig_start,
1476                                           disk_bytenr, /* block_start */
1477                                           num_bytes, /* block_len */
1478                                           disk_num_bytes, /* orig_block_len */
1479                                           ram_bytes, BTRFS_COMPRESS_NONE,
1480                                           BTRFS_ORDERED_PREALLOC);
1481                         if (IS_ERR(em)) {
1482                                 if (nocow)
1483                                         btrfs_dec_nocow_writers(fs_info,
1484                                                                 disk_bytenr);
1485                                 ret = PTR_ERR(em);
1486                                 goto error;
1487                         }
1488                         free_extent_map(em);
1489                 }
1490
1491                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1492                         type = BTRFS_ORDERED_PREALLOC;
1493                 } else {
1494                         type = BTRFS_ORDERED_NOCOW;
1495                 }
1496
1497                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1498                                                num_bytes, num_bytes, type);
1499                 if (nocow)
1500                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1501                 BUG_ON(ret); /* -ENOMEM */
1502
1503                 if (root->root_key.objectid ==
1504                     BTRFS_DATA_RELOC_TREE_OBJECTID)
1505                         /*
1506                          * Error handled later, as we must prevent
1507                          * extent_clear_unlock_delalloc() in error handler
1508                          * from freeing metadata of created ordered extent.
1509                          */
1510                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1511                                                       num_bytes);
1512
1513                 extent_clear_unlock_delalloc(inode, cur_offset,
1514                                              cur_offset + num_bytes - 1, end,
1515                                              locked_page, EXTENT_LOCKED |
1516                                              EXTENT_DELALLOC |
1517                                              EXTENT_CLEAR_DATA_RESV,
1518                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1519
1520                 cur_offset = extent_end;
1521
1522                 /*
1523                  * btrfs_reloc_clone_csums() error, now we're OK to call error
1524                  * handler, as metadata for created ordered extent will only
1525                  * be freed by btrfs_finish_ordered_io().
1526                  */
1527                 if (ret)
1528                         goto error;
1529                 if (cur_offset > end)
1530                         break;
1531         }
1532         btrfs_release_path(path);
1533
1534         if (cur_offset <= end && cow_start == (u64)-1) {
1535                 cow_start = cur_offset;
1536                 cur_offset = end;
1537         }
1538
1539         if (cow_start != (u64)-1) {
1540                 ret = cow_file_range(inode, locked_page, cow_start, end, end,
1541                                      page_started, nr_written, 1, NULL);
1542                 if (ret)
1543                         goto error;
1544         }
1545
1546 error:
1547         if (ret && cur_offset < end)
1548                 extent_clear_unlock_delalloc(inode, cur_offset, end, end,
1549                                              locked_page, EXTENT_LOCKED |
1550                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1551                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1552                                              PAGE_CLEAR_DIRTY |
1553                                              PAGE_SET_WRITEBACK |
1554                                              PAGE_END_WRITEBACK);
1555         btrfs_free_path(path);
1556         return ret;
1557 }
1558
1559 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1560 {
1561
1562         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1563             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1564                 return 0;
1565
1566         /*
1567          * @defrag_bytes is a hint value, no spinlock held here,
1568          * if is not zero, it means the file is defragging.
1569          * Force cow if given extent needs to be defragged.
1570          */
1571         if (BTRFS_I(inode)->defrag_bytes &&
1572             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1573                            EXTENT_DEFRAG, 0, NULL))
1574                 return 1;
1575
1576         return 0;
1577 }
1578
1579 /*
1580  * extent_io.c call back to do delayed allocation processing
1581  */
1582 static int run_delalloc_range(void *private_data, struct page *locked_page,
1583                               u64 start, u64 end, int *page_started,
1584                               unsigned long *nr_written,
1585                               struct writeback_control *wbc)
1586 {
1587         struct inode *inode = private_data;
1588         int ret;
1589         int force_cow = need_force_cow(inode, start, end);
1590         unsigned int write_flags = wbc_to_write_flags(wbc);
1591
1592         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1593                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1594                                          page_started, 1, nr_written);
1595         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1596                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1597                                          page_started, 0, nr_written);
1598         } else if (!inode_need_compress(inode, start, end)) {
1599                 ret = cow_file_range(inode, locked_page, start, end, end,
1600                                       page_started, nr_written, 1, NULL);
1601         } else {
1602                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1603                         &BTRFS_I(inode)->runtime_flags);
1604                 ret = cow_file_range_async(inode, locked_page, start, end,
1605                                            page_started, nr_written,
1606                                            write_flags);
1607         }
1608         if (ret)
1609                 btrfs_cleanup_ordered_extents(inode, start, end - start + 1);
1610         return ret;
1611 }
1612
1613 static void btrfs_split_extent_hook(void *private_data,
1614                                     struct extent_state *orig, u64 split)
1615 {
1616         struct inode *inode = private_data;
1617         u64 size;
1618
1619         /* not delalloc, ignore it */
1620         if (!(orig->state & EXTENT_DELALLOC))
1621                 return;
1622
1623         size = orig->end - orig->start + 1;
1624         if (size > BTRFS_MAX_EXTENT_SIZE) {
1625                 u32 num_extents;
1626                 u64 new_size;
1627
1628                 /*
1629                  * See the explanation in btrfs_merge_extent_hook, the same
1630                  * applies here, just in reverse.
1631                  */
1632                 new_size = orig->end - split + 1;
1633                 num_extents = count_max_extents(new_size);
1634                 new_size = split - orig->start;
1635                 num_extents += count_max_extents(new_size);
1636                 if (count_max_extents(size) >= num_extents)
1637                         return;
1638         }
1639
1640         spin_lock(&BTRFS_I(inode)->lock);
1641         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1642         spin_unlock(&BTRFS_I(inode)->lock);
1643 }
1644
1645 /*
1646  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1647  * extents so we can keep track of new extents that are just merged onto old
1648  * extents, such as when we are doing sequential writes, so we can properly
1649  * account for the metadata space we'll need.
1650  */
1651 static void btrfs_merge_extent_hook(void *private_data,
1652                                     struct extent_state *new,
1653                                     struct extent_state *other)
1654 {
1655         struct inode *inode = private_data;
1656         u64 new_size, old_size;
1657         u32 num_extents;
1658
1659         /* not delalloc, ignore it */
1660         if (!(other->state & EXTENT_DELALLOC))
1661                 return;
1662
1663         if (new->start > other->start)
1664                 new_size = new->end - other->start + 1;
1665         else
1666                 new_size = other->end - new->start + 1;
1667
1668         /* we're not bigger than the max, unreserve the space and go */
1669         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1670                 spin_lock(&BTRFS_I(inode)->lock);
1671                 btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1672                 spin_unlock(&BTRFS_I(inode)->lock);
1673                 return;
1674         }
1675
1676         /*
1677          * We have to add up either side to figure out how many extents were
1678          * accounted for before we merged into one big extent.  If the number of
1679          * extents we accounted for is <= the amount we need for the new range
1680          * then we can return, otherwise drop.  Think of it like this
1681          *
1682          * [ 4k][MAX_SIZE]
1683          *
1684          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1685          * need 2 outstanding extents, on one side we have 1 and the other side
1686          * we have 1 so they are == and we can return.  But in this case
1687          *
1688          * [MAX_SIZE+4k][MAX_SIZE+4k]
1689          *
1690          * Each range on their own accounts for 2 extents, but merged together
1691          * they are only 3 extents worth of accounting, so we need to drop in
1692          * this case.
1693          */
1694         old_size = other->end - other->start + 1;
1695         num_extents = count_max_extents(old_size);
1696         old_size = new->end - new->start + 1;
1697         num_extents += count_max_extents(old_size);
1698         if (count_max_extents(new_size) >= num_extents)
1699                 return;
1700
1701         spin_lock(&BTRFS_I(inode)->lock);
1702         btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1703         spin_unlock(&BTRFS_I(inode)->lock);
1704 }
1705
1706 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1707                                       struct inode *inode)
1708 {
1709         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1710
1711         spin_lock(&root->delalloc_lock);
1712         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1713                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1714                               &root->delalloc_inodes);
1715                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1716                         &BTRFS_I(inode)->runtime_flags);
1717                 root->nr_delalloc_inodes++;
1718                 if (root->nr_delalloc_inodes == 1) {
1719                         spin_lock(&fs_info->delalloc_root_lock);
1720                         BUG_ON(!list_empty(&root->delalloc_root));
1721                         list_add_tail(&root->delalloc_root,
1722                                       &fs_info->delalloc_roots);
1723                         spin_unlock(&fs_info->delalloc_root_lock);
1724                 }
1725         }
1726         spin_unlock(&root->delalloc_lock);
1727 }
1728
1729
1730 void __btrfs_del_delalloc_inode(struct btrfs_root *root,
1731                                 struct btrfs_inode *inode)
1732 {
1733         struct btrfs_fs_info *fs_info = root->fs_info;
1734
1735         if (!list_empty(&inode->delalloc_inodes)) {
1736                 list_del_init(&inode->delalloc_inodes);
1737                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1738                           &inode->runtime_flags);
1739                 root->nr_delalloc_inodes--;
1740                 if (!root->nr_delalloc_inodes) {
1741                         ASSERT(list_empty(&root->delalloc_inodes));
1742                         spin_lock(&fs_info->delalloc_root_lock);
1743                         BUG_ON(list_empty(&root->delalloc_root));
1744                         list_del_init(&root->delalloc_root);
1745                         spin_unlock(&fs_info->delalloc_root_lock);
1746                 }
1747         }
1748 }
1749
1750 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1751                                      struct btrfs_inode *inode)
1752 {
1753         spin_lock(&root->delalloc_lock);
1754         __btrfs_del_delalloc_inode(root, inode);
1755         spin_unlock(&root->delalloc_lock);
1756 }
1757
1758 /*
1759  * extent_io.c set_bit_hook, used to track delayed allocation
1760  * bytes in this file, and to maintain the list of inodes that
1761  * have pending delalloc work to be done.
1762  */
1763 static void btrfs_set_bit_hook(void *private_data,
1764                                struct extent_state *state, unsigned *bits)
1765 {
1766         struct inode *inode = private_data;
1767
1768         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1769
1770         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1771                 WARN_ON(1);
1772         /*
1773          * set_bit and clear bit hooks normally require _irqsave/restore
1774          * but in this case, we are only testing for the DELALLOC
1775          * bit, which is only set or cleared with irqs on
1776          */
1777         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1778                 struct btrfs_root *root = BTRFS_I(inode)->root;
1779                 u64 len = state->end + 1 - state->start;
1780                 u32 num_extents = count_max_extents(len);
1781                 bool do_list = !btrfs_is_free_space_inode(BTRFS_I(inode));
1782
1783                 spin_lock(&BTRFS_I(inode)->lock);
1784                 btrfs_mod_outstanding_extents(BTRFS_I(inode), num_extents);
1785                 spin_unlock(&BTRFS_I(inode)->lock);
1786
1787                 /* For sanity tests */
1788                 if (btrfs_is_testing(fs_info))
1789                         return;
1790
1791                 percpu_counter_add_batch(&fs_info->delalloc_bytes, len,
1792                                          fs_info->delalloc_batch);
1793                 spin_lock(&BTRFS_I(inode)->lock);
1794                 BTRFS_I(inode)->delalloc_bytes += len;
1795                 if (*bits & EXTENT_DEFRAG)
1796                         BTRFS_I(inode)->defrag_bytes += len;
1797                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1798                                          &BTRFS_I(inode)->runtime_flags))
1799                         btrfs_add_delalloc_inodes(root, inode);
1800                 spin_unlock(&BTRFS_I(inode)->lock);
1801         }
1802
1803         if (!(state->state & EXTENT_DELALLOC_NEW) &&
1804             (*bits & EXTENT_DELALLOC_NEW)) {
1805                 spin_lock(&BTRFS_I(inode)->lock);
1806                 BTRFS_I(inode)->new_delalloc_bytes += state->end + 1 -
1807                         state->start;
1808                 spin_unlock(&BTRFS_I(inode)->lock);
1809         }
1810 }
1811
1812 /*
1813  * extent_io.c clear_bit_hook, see set_bit_hook for why
1814  */
1815 static void btrfs_clear_bit_hook(void *private_data,
1816                                  struct extent_state *state,
1817                                  unsigned *bits)
1818 {
1819         struct btrfs_inode *inode = BTRFS_I((struct inode *)private_data);
1820         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
1821         u64 len = state->end + 1 - state->start;
1822         u32 num_extents = count_max_extents(len);
1823
1824         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG)) {
1825                 spin_lock(&inode->lock);
1826                 inode->defrag_bytes -= len;
1827                 spin_unlock(&inode->lock);
1828         }
1829
1830         /*
1831          * set_bit and clear bit hooks normally require _irqsave/restore
1832          * but in this case, we are only testing for the DELALLOC
1833          * bit, which is only set or cleared with irqs on
1834          */
1835         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1836                 struct btrfs_root *root = inode->root;
1837                 bool do_list = !btrfs_is_free_space_inode(inode);
1838
1839                 spin_lock(&inode->lock);
1840                 btrfs_mod_outstanding_extents(inode, -num_extents);
1841                 spin_unlock(&inode->lock);
1842
1843                 /*
1844                  * We don't reserve metadata space for space cache inodes so we
1845                  * don't need to call dellalloc_release_metadata if there is an
1846                  * error.
1847                  */
1848                 if (*bits & EXTENT_CLEAR_META_RESV &&
1849                     root != fs_info->tree_root)
1850                         btrfs_delalloc_release_metadata(inode, len, false);
1851
1852                 /* For sanity tests. */
1853                 if (btrfs_is_testing(fs_info))
1854                         return;
1855
1856                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID &&
1857                     do_list && !(state->state & EXTENT_NORESERVE) &&
1858                     (*bits & EXTENT_CLEAR_DATA_RESV))
1859                         btrfs_free_reserved_data_space_noquota(
1860                                         &inode->vfs_inode,
1861                                         state->start, len);
1862
1863                 percpu_counter_add_batch(&fs_info->delalloc_bytes, -len,
1864                                          fs_info->delalloc_batch);
1865                 spin_lock(&inode->lock);
1866                 inode->delalloc_bytes -= len;
1867                 if (do_list && inode->delalloc_bytes == 0 &&
1868                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1869                                         &inode->runtime_flags))
1870                         btrfs_del_delalloc_inode(root, inode);
1871                 spin_unlock(&inode->lock);
1872         }
1873
1874         if ((state->state & EXTENT_DELALLOC_NEW) &&
1875             (*bits & EXTENT_DELALLOC_NEW)) {
1876                 spin_lock(&inode->lock);
1877                 ASSERT(inode->new_delalloc_bytes >= len);
1878                 inode->new_delalloc_bytes -= len;
1879                 spin_unlock(&inode->lock);
1880         }
1881 }
1882
1883 /*
1884  * Merge bio hook, this must check the chunk tree to make sure we don't create
1885  * bios that span stripes or chunks
1886  *
1887  * return 1 if page cannot be merged to bio
1888  * return 0 if page can be merged to bio
1889  * return error otherwise
1890  */
1891 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1892                          size_t size, struct bio *bio,
1893                          unsigned long bio_flags)
1894 {
1895         struct inode *inode = page->mapping->host;
1896         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1897         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1898         u64 length = 0;
1899         u64 map_length;
1900         int ret;
1901
1902         if (bio_flags & EXTENT_BIO_COMPRESSED)
1903                 return 0;
1904
1905         length = bio->bi_iter.bi_size;
1906         map_length = length;
1907         ret = btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
1908                               NULL, 0);
1909         if (ret < 0)
1910                 return ret;
1911         if (map_length < length + size)
1912                 return 1;
1913         return 0;
1914 }
1915
1916 /*
1917  * in order to insert checksums into the metadata in large chunks,
1918  * we wait until bio submission time.   All the pages in the bio are
1919  * checksummed and sums are attached onto the ordered extent record.
1920  *
1921  * At IO completion time the cums attached on the ordered extent record
1922  * are inserted into the btree
1923  */
1924 static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio,
1925                                     u64 bio_offset)
1926 {
1927         struct inode *inode = private_data;
1928         blk_status_t ret = 0;
1929
1930         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
1931         BUG_ON(ret); /* -ENOMEM */
1932         return 0;
1933 }
1934
1935 /*
1936  * in order to insert checksums into the metadata in large chunks,
1937  * we wait until bio submission time.   All the pages in the bio are
1938  * checksummed and sums are attached onto the ordered extent record.
1939  *
1940  * At IO completion time the cums attached on the ordered extent record
1941  * are inserted into the btree
1942  */
1943 blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
1944                           int mirror_num)
1945 {
1946         struct inode *inode = private_data;
1947         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1948         blk_status_t ret;
1949
1950         ret = btrfs_map_bio(fs_info, bio, mirror_num, 1);
1951         if (ret) {
1952                 bio->bi_status = ret;
1953                 bio_endio(bio);
1954         }
1955         return ret;
1956 }
1957
1958 /*
1959  * extent_io.c submission hook. This does the right thing for csum calculation
1960  * on write, or reading the csums from the tree before a read.
1961  *
1962  * Rules about async/sync submit,
1963  * a) read:                             sync submit
1964  *
1965  * b) write without checksum:           sync submit
1966  *
1967  * c) write with checksum:
1968  *    c-1) if bio is issued by fsync:   sync submit
1969  *         (sync_writers != 0)
1970  *
1971  *    c-2) if root is reloc root:       sync submit
1972  *         (only in case of buffered IO)
1973  *
1974  *    c-3) otherwise:                   async submit
1975  */
1976 static blk_status_t btrfs_submit_bio_hook(void *private_data, struct bio *bio,
1977                                  int mirror_num, unsigned long bio_flags,
1978                                  u64 bio_offset)
1979 {
1980         struct inode *inode = private_data;
1981         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1982         struct btrfs_root *root = BTRFS_I(inode)->root;
1983         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1984         blk_status_t ret = 0;
1985         int skip_sum;
1986         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1987
1988         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1989
1990         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
1991                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1992
1993         if (bio_op(bio) != REQ_OP_WRITE) {
1994                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
1995                 if (ret)
1996                         goto out;
1997
1998                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1999                         ret = btrfs_submit_compressed_read(inode, bio,
2000                                                            mirror_num,
2001                                                            bio_flags);
2002                         goto out;
2003                 } else if (!skip_sum) {
2004                         ret = btrfs_lookup_bio_sums(inode, bio, NULL);
2005                         if (ret)
2006                                 goto out;
2007                 }
2008                 goto mapit;
2009         } else if (async && !skip_sum) {
2010                 /* csum items have already been cloned */
2011                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2012                         goto mapit;
2013                 /* we're doing a write, do the async checksumming */
2014                 ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, bio_flags,
2015                                           bio_offset, inode,
2016                                           btrfs_submit_bio_start);
2017                 goto out;
2018         } else if (!skip_sum) {
2019                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
2020                 if (ret)
2021                         goto out;
2022         }
2023
2024 mapit:
2025         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
2026
2027 out:
2028         if (ret) {
2029                 bio->bi_status = ret;
2030                 bio_endio(bio);
2031         }
2032         return ret;
2033 }
2034
2035 /*
2036  * given a list of ordered sums record them in the inode.  This happens
2037  * at IO completion time based on sums calculated at bio submission time.
2038  */
2039 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
2040                              struct inode *inode, struct list_head *list)
2041 {
2042         struct btrfs_ordered_sum *sum;
2043         int ret;
2044
2045         list_for_each_entry(sum, list, list) {
2046                 trans->adding_csums = true;
2047                 ret = btrfs_csum_file_blocks(trans,
2048                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
2049                 trans->adding_csums = false;
2050                 if (ret)
2051                         return ret;
2052         }
2053         return 0;
2054 }
2055
2056 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
2057                               unsigned int extra_bits,
2058                               struct extent_state **cached_state, int dedupe)
2059 {
2060         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
2061         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
2062                                    extra_bits, cached_state);
2063 }
2064
2065 /* see btrfs_writepage_start_hook for details on why this is required */
2066 struct btrfs_writepage_fixup {
2067         struct page *page;
2068         struct btrfs_work work;
2069 };
2070
2071 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
2072 {
2073         struct btrfs_writepage_fixup *fixup;
2074         struct btrfs_ordered_extent *ordered;
2075         struct extent_state *cached_state = NULL;
2076         struct extent_changeset *data_reserved = NULL;
2077         struct page *page;
2078         struct inode *inode;
2079         u64 page_start;
2080         u64 page_end;
2081         int ret;
2082
2083         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2084         page = fixup->page;
2085 again:
2086         lock_page(page);
2087         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2088                 ClearPageChecked(page);
2089                 goto out_page;
2090         }
2091
2092         inode = page->mapping->host;
2093         page_start = page_offset(page);
2094         page_end = page_offset(page) + PAGE_SIZE - 1;
2095
2096         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2097                          &cached_state);
2098
2099         /* already ordered? We're done */
2100         if (PagePrivate2(page))
2101                 goto out;
2102
2103         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
2104                                         PAGE_SIZE);
2105         if (ordered) {
2106                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2107                                      page_end, &cached_state);
2108                 unlock_page(page);
2109                 btrfs_start_ordered_extent(inode, ordered, 1);
2110                 btrfs_put_ordered_extent(ordered);
2111                 goto again;
2112         }
2113
2114         ret = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
2115                                            PAGE_SIZE);
2116         if (ret) {
2117                 mapping_set_error(page->mapping, ret);
2118                 end_extent_writepage(page, ret, page_start, page_end);
2119                 ClearPageChecked(page);
2120                 goto out;
2121          }
2122
2123         ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
2124                                         &cached_state, 0);
2125         if (ret) {
2126                 mapping_set_error(page->mapping, ret);
2127                 end_extent_writepage(page, ret, page_start, page_end);
2128                 ClearPageChecked(page);
2129                 goto out;
2130         }
2131
2132         ClearPageChecked(page);
2133         set_page_dirty(page);
2134         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, false);
2135 out:
2136         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2137                              &cached_state);
2138 out_page:
2139         unlock_page(page);
2140         put_page(page);
2141         kfree(fixup);
2142         extent_changeset_free(data_reserved);
2143 }
2144
2145 /*
2146  * There are a few paths in the higher layers of the kernel that directly
2147  * set the page dirty bit without asking the filesystem if it is a
2148  * good idea.  This causes problems because we want to make sure COW
2149  * properly happens and the data=ordered rules are followed.
2150  *
2151  * In our case any range that doesn't have the ORDERED bit set
2152  * hasn't been properly setup for IO.  We kick off an async process
2153  * to fix it up.  The async helper will wait for ordered extents, set
2154  * the delalloc bit and make it safe to write the page.
2155  */
2156 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2157 {
2158         struct inode *inode = page->mapping->host;
2159         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2160         struct btrfs_writepage_fixup *fixup;
2161
2162         /* this page is properly in the ordered list */
2163         if (TestClearPagePrivate2(page))
2164                 return 0;
2165
2166         if (PageChecked(page))
2167                 return -EAGAIN;
2168
2169         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2170         if (!fixup)
2171                 return -EAGAIN;
2172
2173         SetPageChecked(page);
2174         get_page(page);
2175         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2176                         btrfs_writepage_fixup_worker, NULL, NULL);
2177         fixup->page = page;
2178         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2179         return -EBUSY;
2180 }
2181
2182 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2183                                        struct inode *inode, u64 file_pos,
2184                                        u64 disk_bytenr, u64 disk_num_bytes,
2185                                        u64 num_bytes, u64 ram_bytes,
2186                                        u8 compression, u8 encryption,
2187                                        u16 other_encoding, int extent_type)
2188 {
2189         struct btrfs_root *root = BTRFS_I(inode)->root;
2190         struct btrfs_file_extent_item *fi;
2191         struct btrfs_path *path;
2192         struct extent_buffer *leaf;
2193         struct btrfs_key ins;
2194         u64 qg_released;
2195         int extent_inserted = 0;
2196         int ret;
2197
2198         path = btrfs_alloc_path();
2199         if (!path)
2200                 return -ENOMEM;
2201
2202         /*
2203          * we may be replacing one extent in the tree with another.
2204          * The new extent is pinned in the extent map, and we don't want
2205          * to drop it from the cache until it is completely in the btree.
2206          *
2207          * So, tell btrfs_drop_extents to leave this extent in the cache.
2208          * the caller is expected to unpin it and allow it to be merged
2209          * with the others.
2210          */
2211         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2212                                    file_pos + num_bytes, NULL, 0,
2213                                    1, sizeof(*fi), &extent_inserted);
2214         if (ret)
2215                 goto out;
2216
2217         if (!extent_inserted) {
2218                 ins.objectid = btrfs_ino(BTRFS_I(inode));
2219                 ins.offset = file_pos;
2220                 ins.type = BTRFS_EXTENT_DATA_KEY;
2221
2222                 path->leave_spinning = 1;
2223                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2224                                               sizeof(*fi));
2225                 if (ret)
2226                         goto out;
2227         }
2228         leaf = path->nodes[0];
2229         fi = btrfs_item_ptr(leaf, path->slots[0],
2230                             struct btrfs_file_extent_item);
2231         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2232         btrfs_set_file_extent_type(leaf, fi, extent_type);
2233         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2234         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2235         btrfs_set_file_extent_offset(leaf, fi, 0);
2236         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2237         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2238         btrfs_set_file_extent_compression(leaf, fi, compression);
2239         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2240         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2241
2242         btrfs_mark_buffer_dirty(leaf);
2243         btrfs_release_path(path);
2244
2245         inode_add_bytes(inode, num_bytes);
2246
2247         ins.objectid = disk_bytenr;
2248         ins.offset = disk_num_bytes;
2249         ins.type = BTRFS_EXTENT_ITEM_KEY;
2250
2251         /*
2252          * Release the reserved range from inode dirty range map, as it is
2253          * already moved into delayed_ref_head
2254          */
2255         ret = btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2256         if (ret < 0)
2257                 goto out;
2258         qg_released = ret;
2259         ret = btrfs_alloc_reserved_file_extent(trans, root,
2260                                                btrfs_ino(BTRFS_I(inode)),
2261                                                file_pos, qg_released, &ins);
2262 out:
2263         btrfs_free_path(path);
2264
2265         return ret;
2266 }
2267
2268 /* snapshot-aware defrag */
2269 struct sa_defrag_extent_backref {
2270         struct rb_node node;
2271         struct old_sa_defrag_extent *old;
2272         u64 root_id;
2273         u64 inum;
2274         u64 file_pos;
2275         u64 extent_offset;
2276         u64 num_bytes;
2277         u64 generation;
2278 };
2279
2280 struct old_sa_defrag_extent {
2281         struct list_head list;
2282         struct new_sa_defrag_extent *new;
2283
2284         u64 extent_offset;
2285         u64 bytenr;
2286         u64 offset;
2287         u64 len;
2288         int count;
2289 };
2290
2291 struct new_sa_defrag_extent {
2292         struct rb_root root;
2293         struct list_head head;
2294         struct btrfs_path *path;
2295         struct inode *inode;
2296         u64 file_pos;
2297         u64 len;
2298         u64 bytenr;
2299         u64 disk_len;
2300         u8 compress_type;
2301 };
2302
2303 static int backref_comp(struct sa_defrag_extent_backref *b1,
2304                         struct sa_defrag_extent_backref *b2)
2305 {
2306         if (b1->root_id < b2->root_id)
2307                 return -1;
2308         else if (b1->root_id > b2->root_id)
2309                 return 1;
2310
2311         if (b1->inum < b2->inum)
2312                 return -1;
2313         else if (b1->inum > b2->inum)
2314                 return 1;
2315
2316         if (b1->file_pos < b2->file_pos)
2317                 return -1;
2318         else if (b1->file_pos > b2->file_pos)
2319                 return 1;
2320
2321         /*
2322          * [------------------------------] ===> (a range of space)
2323          *     |<--->|   |<---->| =============> (fs/file tree A)
2324          * |<---------------------------->| ===> (fs/file tree B)
2325          *
2326          * A range of space can refer to two file extents in one tree while
2327          * refer to only one file extent in another tree.
2328          *
2329          * So we may process a disk offset more than one time(two extents in A)
2330          * and locate at the same extent(one extent in B), then insert two same
2331          * backrefs(both refer to the extent in B).
2332          */
2333         return 0;
2334 }
2335
2336 static void backref_insert(struct rb_root *root,
2337                            struct sa_defrag_extent_backref *backref)
2338 {
2339         struct rb_node **p = &root->rb_node;
2340         struct rb_node *parent = NULL;
2341         struct sa_defrag_extent_backref *entry;
2342         int ret;
2343
2344         while (*p) {
2345                 parent = *p;
2346                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2347
2348                 ret = backref_comp(backref, entry);
2349                 if (ret < 0)
2350                         p = &(*p)->rb_left;
2351                 else
2352                         p = &(*p)->rb_right;
2353         }
2354
2355         rb_link_node(&backref->node, parent, p);
2356         rb_insert_color(&backref->node, root);
2357 }
2358
2359 /*
2360  * Note the backref might has changed, and in this case we just return 0.
2361  */
2362 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2363                                        void *ctx)
2364 {
2365         struct btrfs_file_extent_item *extent;
2366         struct old_sa_defrag_extent *old = ctx;
2367         struct new_sa_defrag_extent *new = old->new;
2368         struct btrfs_path *path = new->path;
2369         struct btrfs_key key;
2370         struct btrfs_root *root;
2371         struct sa_defrag_extent_backref *backref;
2372         struct extent_buffer *leaf;
2373         struct inode *inode = new->inode;
2374         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2375         int slot;
2376         int ret;
2377         u64 extent_offset;
2378         u64 num_bytes;
2379
2380         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2381             inum == btrfs_ino(BTRFS_I(inode)))
2382                 return 0;
2383
2384         key.objectid = root_id;
2385         key.type = BTRFS_ROOT_ITEM_KEY;
2386         key.offset = (u64)-1;
2387
2388         root = btrfs_read_fs_root_no_name(fs_info, &key);
2389         if (IS_ERR(root)) {
2390                 if (PTR_ERR(root) == -ENOENT)
2391                         return 0;
2392                 WARN_ON(1);
2393                 btrfs_debug(fs_info, "inum=%llu, offset=%llu, root_id=%llu",
2394                          inum, offset, root_id);
2395                 return PTR_ERR(root);
2396         }
2397
2398         key.objectid = inum;
2399         key.type = BTRFS_EXTENT_DATA_KEY;
2400         if (offset > (u64)-1 << 32)
2401                 key.offset = 0;
2402         else
2403                 key.offset = offset;
2404
2405         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2406         if (WARN_ON(ret < 0))
2407                 return ret;
2408         ret = 0;
2409
2410         while (1) {
2411                 cond_resched();
2412
2413                 leaf = path->nodes[0];
2414                 slot = path->slots[0];
2415
2416                 if (slot >= btrfs_header_nritems(leaf)) {
2417                         ret = btrfs_next_leaf(root, path);
2418                         if (ret < 0) {
2419                                 goto out;
2420                         } else if (ret > 0) {
2421                                 ret = 0;
2422                                 goto out;
2423                         }
2424                         continue;
2425                 }
2426
2427                 path->slots[0]++;
2428
2429                 btrfs_item_key_to_cpu(leaf, &key, slot);
2430
2431                 if (key.objectid > inum)
2432                         goto out;
2433
2434                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2435                         continue;
2436
2437                 extent = btrfs_item_ptr(leaf, slot,
2438                                         struct btrfs_file_extent_item);
2439
2440                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2441                         continue;
2442
2443                 /*
2444                  * 'offset' refers to the exact key.offset,
2445                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2446                  * (key.offset - extent_offset).
2447                  */
2448                 if (key.offset != offset)
2449                         continue;
2450
2451                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2452                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2453
2454                 if (extent_offset >= old->extent_offset + old->offset +
2455                     old->len || extent_offset + num_bytes <=
2456                     old->extent_offset + old->offset)
2457                         continue;
2458                 break;
2459         }
2460
2461         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2462         if (!backref) {
2463                 ret = -ENOENT;
2464                 goto out;
2465         }
2466
2467         backref->root_id = root_id;
2468         backref->inum = inum;
2469         backref->file_pos = offset;
2470         backref->num_bytes = num_bytes;
2471         backref->extent_offset = extent_offset;
2472         backref->generation = btrfs_file_extent_generation(leaf, extent);
2473         backref->old = old;
2474         backref_insert(&new->root, backref);
2475         old->count++;
2476 out:
2477         btrfs_release_path(path);
2478         WARN_ON(ret);
2479         return ret;
2480 }
2481
2482 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2483                                    struct new_sa_defrag_extent *new)
2484 {
2485         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2486         struct old_sa_defrag_extent *old, *tmp;
2487         int ret;
2488
2489         new->path = path;
2490
2491         list_for_each_entry_safe(old, tmp, &new->head, list) {
2492                 ret = iterate_inodes_from_logical(old->bytenr +
2493                                                   old->extent_offset, fs_info,
2494                                                   path, record_one_backref,
2495                                                   old, false);
2496                 if (ret < 0 && ret != -ENOENT)
2497                         return false;
2498
2499                 /* no backref to be processed for this extent */
2500                 if (!old->count) {
2501                         list_del(&old->list);
2502                         kfree(old);
2503                 }
2504         }
2505
2506         if (list_empty(&new->head))
2507                 return false;
2508
2509         return true;
2510 }
2511
2512 static int relink_is_mergable(struct extent_buffer *leaf,
2513                               struct btrfs_file_extent_item *fi,
2514                               struct new_sa_defrag_extent *new)
2515 {
2516         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2517                 return 0;
2518
2519         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2520                 return 0;
2521
2522         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2523                 return 0;
2524
2525         if (btrfs_file_extent_encryption(leaf, fi) ||
2526             btrfs_file_extent_other_encoding(leaf, fi))
2527                 return 0;
2528
2529         return 1;
2530 }
2531
2532 /*
2533  * Note the backref might has changed, and in this case we just return 0.
2534  */
2535 static noinline int relink_extent_backref(struct btrfs_path *path,
2536                                  struct sa_defrag_extent_backref *prev,
2537                                  struct sa_defrag_extent_backref *backref)
2538 {
2539         struct btrfs_file_extent_item *extent;
2540         struct btrfs_file_extent_item *item;
2541         struct btrfs_ordered_extent *ordered;
2542         struct btrfs_trans_handle *trans;
2543         struct btrfs_root *root;
2544         struct btrfs_key key;
2545         struct extent_buffer *leaf;
2546         struct old_sa_defrag_extent *old = backref->old;
2547         struct new_sa_defrag_extent *new = old->new;
2548         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2549         struct inode *inode;
2550         struct extent_state *cached = NULL;
2551         int ret = 0;
2552         u64 start;
2553         u64 len;
2554         u64 lock_start;
2555         u64 lock_end;
2556         bool merge = false;
2557         int index;
2558
2559         if (prev && prev->root_id == backref->root_id &&
2560             prev->inum == backref->inum &&
2561             prev->file_pos + prev->num_bytes == backref->file_pos)
2562                 merge = true;
2563
2564         /* step 1: get root */
2565         key.objectid = backref->root_id;
2566         key.type = BTRFS_ROOT_ITEM_KEY;
2567         key.offset = (u64)-1;
2568
2569         index = srcu_read_lock(&fs_info->subvol_srcu);
2570
2571         root = btrfs_read_fs_root_no_name(fs_info, &key);
2572         if (IS_ERR(root)) {
2573                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2574                 if (PTR_ERR(root) == -ENOENT)
2575                         return 0;
2576                 return PTR_ERR(root);
2577         }
2578
2579         if (btrfs_root_readonly(root)) {
2580                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2581                 return 0;
2582         }
2583
2584         /* step 2: get inode */
2585         key.objectid = backref->inum;
2586         key.type = BTRFS_INODE_ITEM_KEY;
2587         key.offset = 0;
2588
2589         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2590         if (IS_ERR(inode)) {
2591                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2592                 return 0;
2593         }
2594
2595         srcu_read_unlock(&fs_info->subvol_srcu, index);
2596
2597         /* step 3: relink backref */
2598         lock_start = backref->file_pos;
2599         lock_end = backref->file_pos + backref->num_bytes - 1;
2600         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2601                          &cached);
2602
2603         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2604         if (ordered) {
2605                 btrfs_put_ordered_extent(ordered);
2606                 goto out_unlock;
2607         }
2608
2609         trans = btrfs_join_transaction(root);
2610         if (IS_ERR(trans)) {
2611                 ret = PTR_ERR(trans);
2612                 goto out_unlock;
2613         }
2614
2615         key.objectid = backref->inum;
2616         key.type = BTRFS_EXTENT_DATA_KEY;
2617         key.offset = backref->file_pos;
2618
2619         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2620         if (ret < 0) {
2621                 goto out_free_path;
2622         } else if (ret > 0) {
2623                 ret = 0;
2624                 goto out_free_path;
2625         }
2626
2627         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2628                                 struct btrfs_file_extent_item);
2629
2630         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2631             backref->generation)
2632                 goto out_free_path;
2633
2634         btrfs_release_path(path);
2635
2636         start = backref->file_pos;
2637         if (backref->extent_offset < old->extent_offset + old->offset)
2638                 start += old->extent_offset + old->offset -
2639                          backref->extent_offset;
2640
2641         len = min(backref->extent_offset + backref->num_bytes,
2642                   old->extent_offset + old->offset + old->len);
2643         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2644
2645         ret = btrfs_drop_extents(trans, root, inode, start,
2646                                  start + len, 1);
2647         if (ret)
2648                 goto out_free_path;
2649 again:
2650         key.objectid = btrfs_ino(BTRFS_I(inode));
2651         key.type = BTRFS_EXTENT_DATA_KEY;
2652         key.offset = start;
2653
2654         path->leave_spinning = 1;
2655         if (merge) {
2656                 struct btrfs_file_extent_item *fi;
2657                 u64 extent_len;
2658                 struct btrfs_key found_key;
2659
2660                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2661                 if (ret < 0)
2662                         goto out_free_path;
2663
2664                 path->slots[0]--;
2665                 leaf = path->nodes[0];
2666                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2667
2668                 fi = btrfs_item_ptr(leaf, path->slots[0],
2669                                     struct btrfs_file_extent_item);
2670                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2671
2672                 if (extent_len + found_key.offset == start &&
2673                     relink_is_mergable(leaf, fi, new)) {
2674                         btrfs_set_file_extent_num_bytes(leaf, fi,
2675                                                         extent_len + len);
2676                         btrfs_mark_buffer_dirty(leaf);
2677                         inode_add_bytes(inode, len);
2678
2679                         ret = 1;
2680                         goto out_free_path;
2681                 } else {
2682                         merge = false;
2683                         btrfs_release_path(path);
2684                         goto again;
2685                 }
2686         }
2687
2688         ret = btrfs_insert_empty_item(trans, root, path, &key,
2689                                         sizeof(*extent));
2690         if (ret) {
2691                 btrfs_abort_transaction(trans, ret);
2692                 goto out_free_path;
2693         }
2694
2695         leaf = path->nodes[0];
2696         item = btrfs_item_ptr(leaf, path->slots[0],
2697                                 struct btrfs_file_extent_item);
2698         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2699         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2700         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2701         btrfs_set_file_extent_num_bytes(leaf, item, len);
2702         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2703         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2704         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2705         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2706         btrfs_set_file_extent_encryption(leaf, item, 0);
2707         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2708
2709         btrfs_mark_buffer_dirty(leaf);
2710         inode_add_bytes(inode, len);
2711         btrfs_release_path(path);
2712
2713         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2714                         new->disk_len, 0,
2715                         backref->root_id, backref->inum,
2716                         new->file_pos); /* start - extent_offset */
2717         if (ret) {
2718                 btrfs_abort_transaction(trans, ret);
2719                 goto out_free_path;
2720         }
2721
2722         ret = 1;
2723 out_free_path:
2724         btrfs_release_path(path);
2725         path->leave_spinning = 0;
2726         btrfs_end_transaction(trans);
2727 out_unlock:
2728         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2729                              &cached);
2730         iput(inode);
2731         return ret;
2732 }
2733
2734 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2735 {
2736         struct old_sa_defrag_extent *old, *tmp;
2737
2738         if (!new)
2739                 return;
2740
2741         list_for_each_entry_safe(old, tmp, &new->head, list) {
2742                 kfree(old);
2743         }
2744         kfree(new);
2745 }
2746
2747 static void relink_file_extents(struct new_sa_defrag_extent *new)
2748 {
2749         struct btrfs_fs_info *fs_info = btrfs_sb(new->inode->i_sb);
2750         struct btrfs_path *path;
2751         struct sa_defrag_extent_backref *backref;
2752         struct sa_defrag_extent_backref *prev = NULL;
2753         struct rb_node *node;
2754         int ret;
2755
2756         path = btrfs_alloc_path();
2757         if (!path)
2758                 return;
2759
2760         if (!record_extent_backrefs(path, new)) {
2761                 btrfs_free_path(path);
2762                 goto out;
2763         }
2764         btrfs_release_path(path);
2765
2766         while (1) {
2767                 node = rb_first(&new->root);
2768                 if (!node)
2769                         break;
2770                 rb_erase(node, &new->root);
2771
2772                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2773
2774                 ret = relink_extent_backref(path, prev, backref);
2775                 WARN_ON(ret < 0);
2776
2777                 kfree(prev);
2778
2779                 if (ret == 1)
2780                         prev = backref;
2781                 else
2782                         prev = NULL;
2783                 cond_resched();
2784         }
2785         kfree(prev);
2786
2787         btrfs_free_path(path);
2788 out:
2789         free_sa_defrag_extent(new);
2790
2791         atomic_dec(&fs_info->defrag_running);
2792         wake_up(&fs_info->transaction_wait);
2793 }
2794
2795 static struct new_sa_defrag_extent *
2796 record_old_file_extents(struct inode *inode,
2797                         struct btrfs_ordered_extent *ordered)
2798 {
2799         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2800         struct btrfs_root *root = BTRFS_I(inode)->root;
2801         struct btrfs_path *path;
2802         struct btrfs_key key;
2803         struct old_sa_defrag_extent *old;
2804         struct new_sa_defrag_extent *new;
2805         int ret;
2806
2807         new = kmalloc(sizeof(*new), GFP_NOFS);
2808         if (!new)
2809                 return NULL;
2810
2811         new->inode = inode;
2812         new->file_pos = ordered->file_offset;
2813         new->len = ordered->len;
2814         new->bytenr = ordered->start;
2815         new->disk_len = ordered->disk_len;
2816         new->compress_type = ordered->compress_type;
2817         new->root = RB_ROOT;
2818         INIT_LIST_HEAD(&new->head);
2819
2820         path = btrfs_alloc_path();
2821         if (!path)
2822                 goto out_kfree;
2823
2824         key.objectid = btrfs_ino(BTRFS_I(inode));
2825         key.type = BTRFS_EXTENT_DATA_KEY;
2826         key.offset = new->file_pos;
2827
2828         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2829         if (ret < 0)
2830                 goto out_free_path;
2831         if (ret > 0 && path->slots[0] > 0)
2832                 path->slots[0]--;
2833
2834         /* find out all the old extents for the file range */
2835         while (1) {
2836                 struct btrfs_file_extent_item *extent;
2837                 struct extent_buffer *l;
2838                 int slot;
2839                 u64 num_bytes;
2840                 u64 offset;
2841                 u64 end;
2842                 u64 disk_bytenr;
2843                 u64 extent_offset;
2844
2845                 l = path->nodes[0];
2846                 slot = path->slots[0];
2847
2848                 if (slot >= btrfs_header_nritems(l)) {
2849                         ret = btrfs_next_leaf(root, path);
2850                         if (ret < 0)
2851                                 goto out_free_path;
2852                         else if (ret > 0)
2853                                 break;
2854                         continue;
2855                 }
2856
2857                 btrfs_item_key_to_cpu(l, &key, slot);
2858
2859                 if (key.objectid != btrfs_ino(BTRFS_I(inode)))
2860                         break;
2861                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2862                         break;
2863                 if (key.offset >= new->file_pos + new->len)
2864                         break;
2865
2866                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2867
2868                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2869                 if (key.offset + num_bytes < new->file_pos)
2870                         goto next;
2871
2872                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2873                 if (!disk_bytenr)
2874                         goto next;
2875
2876                 extent_offset = btrfs_file_extent_offset(l, extent);
2877
2878                 old = kmalloc(sizeof(*old), GFP_NOFS);
2879                 if (!old)
2880                         goto out_free_path;
2881
2882                 offset = max(new->file_pos, key.offset);
2883                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2884
2885                 old->bytenr = disk_bytenr;
2886                 old->extent_offset = extent_offset;
2887                 old->offset = offset - key.offset;
2888                 old->len = end - offset;
2889                 old->new = new;
2890                 old->count = 0;
2891                 list_add_tail(&old->list, &new->head);
2892 next:
2893                 path->slots[0]++;
2894                 cond_resched();
2895         }
2896
2897         btrfs_free_path(path);
2898         atomic_inc(&fs_info->defrag_running);
2899
2900         return new;
2901
2902 out_free_path:
2903         btrfs_free_path(path);
2904 out_kfree:
2905         free_sa_defrag_extent(new);
2906         return NULL;
2907 }
2908
2909 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2910                                          u64 start, u64 len)
2911 {
2912         struct btrfs_block_group_cache *cache;
2913
2914         cache = btrfs_lookup_block_group(fs_info, start);
2915         ASSERT(cache);
2916
2917         spin_lock(&cache->lock);
2918         cache->delalloc_bytes -= len;
2919         spin_unlock(&cache->lock);
2920
2921         btrfs_put_block_group(cache);
2922 }
2923
2924 /* as ordered data IO finishes, this gets called so we can finish
2925  * an ordered extent if the range of bytes in the file it covers are
2926  * fully written.
2927  */
2928 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2929 {
2930         struct inode *inode = ordered_extent->inode;
2931         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2932         struct btrfs_root *root = BTRFS_I(inode)->root;
2933         struct btrfs_trans_handle *trans = NULL;
2934         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2935         struct extent_state *cached_state = NULL;
2936         struct new_sa_defrag_extent *new = NULL;
2937         int compress_type = 0;
2938         int ret = 0;
2939         u64 logical_len = ordered_extent->len;
2940         bool nolock;
2941         bool truncated = false;
2942         bool range_locked = false;
2943         bool clear_new_delalloc_bytes = false;
2944         bool clear_reserved_extent = true;
2945
2946         if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2947             !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
2948             !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
2949                 clear_new_delalloc_bytes = true;
2950
2951         nolock = btrfs_is_free_space_inode(BTRFS_I(inode));
2952
2953         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2954                 ret = -EIO;
2955                 goto out;
2956         }
2957
2958         btrfs_free_io_failure_record(BTRFS_I(inode),
2959                         ordered_extent->file_offset,
2960                         ordered_extent->file_offset +
2961                         ordered_extent->len - 1);
2962
2963         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2964                 truncated = true;
2965                 logical_len = ordered_extent->truncated_len;
2966                 /* Truncated the entire extent, don't bother adding */
2967                 if (!logical_len)
2968                         goto out;
2969         }
2970
2971         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2972                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2973
2974                 /*
2975                  * For mwrite(mmap + memset to write) case, we still reserve
2976                  * space for NOCOW range.
2977                  * As NOCOW won't cause a new delayed ref, just free the space
2978                  */
2979                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
2980                                        ordered_extent->len);
2981                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2982                 if (nolock)
2983                         trans = btrfs_join_transaction_nolock(root);
2984                 else
2985                         trans = btrfs_join_transaction(root);
2986                 if (IS_ERR(trans)) {
2987                         ret = PTR_ERR(trans);
2988                         trans = NULL;
2989                         goto out;
2990                 }
2991                 trans->block_rsv = &BTRFS_I(inode)->block_rsv;
2992                 ret = btrfs_update_inode_fallback(trans, root, inode);
2993                 if (ret) /* -ENOMEM or corruption */
2994                         btrfs_abort_transaction(trans, ret);
2995                 goto out;
2996         }
2997
2998         range_locked = true;
2999         lock_extent_bits(io_tree, ordered_extent->file_offset,
3000                          ordered_extent->file_offset + ordered_extent->len - 1,
3001                          &cached_state);
3002
3003         ret = test_range_bit(io_tree, ordered_extent->file_offset,
3004                         ordered_extent->file_offset + ordered_extent->len - 1,
3005                         EXTENT_DEFRAG, 0, cached_state);
3006         if (ret) {
3007                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
3008                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
3009                         /* the inode is shared */
3010                         new = record_old_file_extents(inode, ordered_extent);
3011
3012                 clear_extent_bit(io_tree, ordered_extent->file_offset,
3013                         ordered_extent->file_offset + ordered_extent->len - 1,
3014                         EXTENT_DEFRAG, 0, 0, &cached_state);
3015         }
3016
3017         if (nolock)
3018                 trans = btrfs_join_transaction_nolock(root);
3019         else
3020                 trans = btrfs_join_transaction(root);
3021         if (IS_ERR(trans)) {
3022                 ret = PTR_ERR(trans);
3023                 trans = NULL;
3024                 goto out;
3025         }
3026
3027         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
3028
3029         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
3030                 compress_type = ordered_extent->compress_type;
3031         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
3032                 BUG_ON(compress_type);
3033                 btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
3034                                        ordered_extent->len);
3035                 ret = btrfs_mark_extent_written(trans, BTRFS_I(inode),
3036                                                 ordered_extent->file_offset,
3037                                                 ordered_extent->file_offset +
3038                                                 logical_len);
3039         } else {
3040                 BUG_ON(root == fs_info->tree_root);
3041                 ret = insert_reserved_file_extent(trans, inode,
3042                                                 ordered_extent->file_offset,
3043                                                 ordered_extent->start,
3044                                                 ordered_extent->disk_len,
3045                                                 logical_len, logical_len,
3046                                                 compress_type, 0, 0,
3047                                                 BTRFS_FILE_EXTENT_REG);
3048                 if (!ret) {
3049                         clear_reserved_extent = false;
3050                         btrfs_release_delalloc_bytes(fs_info,
3051                                                      ordered_extent->start,
3052                                                      ordered_extent->disk_len);
3053                 }
3054         }
3055         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
3056                            ordered_extent->file_offset, ordered_extent->len,
3057                            trans->transid);
3058         if (ret < 0) {
3059                 btrfs_abort_transaction(trans, ret);
3060                 goto out;
3061         }
3062
3063         ret = add_pending_csums(trans, inode, &ordered_extent->list);
3064         if (ret) {
3065                 btrfs_abort_transaction(trans, ret);
3066                 goto out;
3067         }
3068
3069         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
3070         ret = btrfs_update_inode_fallback(trans, root, inode);
3071         if (ret) { /* -ENOMEM or corruption */
3072                 btrfs_abort_transaction(trans, ret);
3073                 goto out;
3074         }
3075         ret = 0;
3076 out:
3077         if (range_locked || clear_new_delalloc_bytes) {
3078                 unsigned int clear_bits = 0;
3079
3080                 if (range_locked)
3081                         clear_bits |= EXTENT_LOCKED;
3082                 if (clear_new_delalloc_bytes)
3083                         clear_bits |= EXTENT_DELALLOC_NEW;
3084                 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3085                                  ordered_extent->file_offset,
3086                                  ordered_extent->file_offset +
3087                                  ordered_extent->len - 1,
3088                                  clear_bits,
3089                                  (clear_bits & EXTENT_LOCKED) ? 1 : 0,
3090                                  0, &cached_state);
3091         }
3092
3093         if (trans)
3094                 btrfs_end_transaction(trans);
3095
3096         if (ret || truncated) {
3097                 u64 start, end;
3098
3099                 if (truncated)
3100                         start = ordered_extent->file_offset + logical_len;
3101                 else
3102                         start = ordered_extent->file_offset;
3103                 end = ordered_extent->file_offset + ordered_extent->len - 1;
3104                 clear_extent_uptodate(io_tree, start, end, NULL);
3105
3106                 /* Drop the cache for the part of the extent we didn't write. */
3107                 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3108
3109                 /*
3110                  * If the ordered extent had an IOERR or something else went
3111                  * wrong we need to return the space for this ordered extent
3112                  * back to the allocator.  We only free the extent in the
3113                  * truncated case if we didn't write out the extent at all.
3114                  *
3115                  * If we made it past insert_reserved_file_extent before we
3116                  * errored out then we don't need to do this as the accounting
3117                  * has already been done.
3118                  */
3119                 if ((ret || !logical_len) &&
3120                     clear_reserved_extent &&
3121                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
3122                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
3123                         btrfs_free_reserved_extent(fs_info,
3124                                                    ordered_extent->start,
3125                                                    ordered_extent->disk_len, 1);
3126         }
3127
3128
3129         /*
3130          * This needs to be done to make sure anybody waiting knows we are done
3131          * updating everything for this ordered extent.
3132          */
3133         btrfs_remove_ordered_extent(inode, ordered_extent);
3134
3135         /* for snapshot-aware defrag */
3136         if (new) {
3137                 if (ret) {
3138                         free_sa_defrag_extent(new);
3139                         atomic_dec(&fs_info->defrag_running);
3140                 } else {
3141                         relink_file_extents(new);
3142                 }
3143         }
3144
3145         /* once for us */
3146         btrfs_put_ordered_extent(ordered_extent);
3147         /* once for the tree */
3148         btrfs_put_ordered_extent(ordered_extent);
3149
3150         /* Try to release some metadata so we don't get an OOM but don't wait */
3151         btrfs_btree_balance_dirty_nodelay(fs_info);
3152
3153         return ret;
3154 }
3155
3156 static void finish_ordered_fn(struct btrfs_work *work)
3157 {
3158         struct btrfs_ordered_extent *ordered_extent;
3159         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3160         btrfs_finish_ordered_io(ordered_extent);
3161 }
3162
3163 static void btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3164                                 struct extent_state *state, int uptodate)
3165 {
3166         struct inode *inode = page->mapping->host;
3167         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3168         struct btrfs_ordered_extent *ordered_extent = NULL;
3169         struct btrfs_workqueue *wq;
3170         btrfs_work_func_t func;
3171
3172         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3173
3174         ClearPagePrivate2(page);
3175         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3176                                             end - start + 1, uptodate))
3177                 return;
3178
3179         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
3180                 wq = fs_info->endio_freespace_worker;
3181                 func = btrfs_freespace_write_helper;
3182         } else {
3183                 wq = fs_info->endio_write_workers;
3184                 func = btrfs_endio_write_helper;
3185         }
3186
3187         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3188                         NULL);
3189         btrfs_queue_work(wq, &ordered_extent->work);
3190 }
3191
3192 static int __readpage_endio_check(struct inode *inode,
3193                                   struct btrfs_io_bio *io_bio,
3194                                   int icsum, struct page *page,
3195                                   int pgoff, u64 start, size_t len)
3196 {
3197         char *kaddr;
3198         u32 csum_expected;
3199         u32 csum = ~(u32)0;
3200
3201         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3202
3203         kaddr = kmap_atomic(page);
3204         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3205         btrfs_csum_final(csum, (u8 *)&csum);
3206         if (csum != csum_expected)
3207                 goto zeroit;
3208
3209         kunmap_atomic(kaddr);
3210         return 0;
3211 zeroit:
3212         btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected,
3213                                     io_bio->mirror_num);
3214         memset(kaddr + pgoff, 1, len);
3215         flush_dcache_page(page);
3216         kunmap_atomic(kaddr);
3217         return -EIO;
3218 }
3219
3220 /*
3221  * when reads are done, we need to check csums to verify the data is correct
3222  * if there's a match, we allow the bio to finish.  If not, the code in
3223  * extent_io.c will try to find good copies for us.
3224  */
3225 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3226                                       u64 phy_offset, struct page *page,
3227                                       u64 start, u64 end, int mirror)
3228 {
3229         size_t offset = start - page_offset(page);
3230         struct inode *inode = page->mapping->host;
3231         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3232         struct btrfs_root *root = BTRFS_I(inode)->root;
3233
3234         if (PageChecked(page)) {
3235                 ClearPageChecked(page);
3236                 return 0;
3237         }
3238
3239         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3240                 return 0;
3241
3242         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3243             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3244                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3245                 return 0;
3246         }
3247
3248         phy_offset >>= inode->i_sb->s_blocksize_bits;
3249         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3250                                       start, (size_t)(end - start + 1));
3251 }
3252
3253 /*
3254  * btrfs_add_delayed_iput - perform a delayed iput on @inode
3255  *
3256  * @inode: The inode we want to perform iput on
3257  *
3258  * This function uses the generic vfs_inode::i_count to track whether we should
3259  * just decrement it (in case it's > 1) or if this is the last iput then link
3260  * the inode to the delayed iput machinery. Delayed iputs are processed at
3261  * transaction commit time/superblock commit/cleaner kthread.
3262  */
3263 void btrfs_add_delayed_iput(struct inode *inode)
3264 {
3265         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3266         struct btrfs_inode *binode = BTRFS_I(inode);
3267
3268         if (atomic_add_unless(&inode->i_count, -1, 1))
3269                 return;
3270
3271         spin_lock(&fs_info->delayed_iput_lock);
3272         ASSERT(list_empty(&binode->delayed_iput));
3273         list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3274         spin_unlock(&fs_info->delayed_iput_lock);
3275 }
3276
3277 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
3278 {
3279
3280         spin_lock(&fs_info->delayed_iput_lock);
3281         while (!list_empty(&fs_info->delayed_iputs)) {
3282                 struct btrfs_inode *inode;
3283
3284                 inode = list_first_entry(&fs_info->delayed_iputs,
3285                                 struct btrfs_inode, delayed_iput);
3286                 list_del_init(&inode->delayed_iput);
3287                 spin_unlock(&fs_info->delayed_iput_lock);
3288                 iput(&inode->vfs_inode);
3289                 spin_lock(&fs_info->delayed_iput_lock);
3290         }
3291         spin_unlock(&fs_info->delayed_iput_lock);
3292 }
3293
3294 /*
3295  * This creates an orphan entry for the given inode in case something goes wrong
3296  * in the middle of an unlink.
3297  */
3298 int btrfs_orphan_add(struct btrfs_trans_handle *trans,
3299                      struct btrfs_inode *inode)
3300 {
3301         int ret;
3302
3303         ret = btrfs_insert_orphan_item(trans, inode->root, btrfs_ino(inode));
3304         if (ret && ret != -EEXIST) {
3305                 btrfs_abort_transaction(trans, ret);
3306                 return ret;
3307         }
3308
3309         return 0;
3310 }
3311
3312 /*
3313  * We have done the delete so we can go ahead and remove the orphan item for
3314  * this particular inode.
3315  */
3316 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3317                             struct btrfs_inode *inode)
3318 {
3319         return btrfs_del_orphan_item(trans, inode->root, btrfs_ino(inode));
3320 }
3321
3322 /*
3323  * this cleans up any orphans that may be left on the list from the last use
3324  * of this root.
3325  */
3326 int btrfs_orphan_cleanup(struct btrfs_root *root)
3327 {
3328         struct btrfs_fs_info *fs_info = root->fs_info;
3329         struct btrfs_path *path;
3330         struct extent_buffer *leaf;
3331         struct btrfs_key key, found_key;
3332         struct btrfs_trans_handle *trans;
3333         struct inode *inode;
3334         u64 last_objectid = 0;
3335         int ret = 0, nr_unlink = 0;
3336
3337         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3338                 return 0;
3339
3340         path = btrfs_alloc_path();
3341         if (!path) {
3342                 ret = -ENOMEM;
3343                 goto out;
3344         }
3345         path->reada = READA_BACK;
3346
3347         key.objectid = BTRFS_ORPHAN_OBJECTID;
3348         key.type = BTRFS_ORPHAN_ITEM_KEY;
3349         key.offset = (u64)-1;
3350
3351         while (1) {
3352                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3353                 if (ret < 0)
3354                         goto out;
3355
3356                 /*
3357                  * if ret == 0 means we found what we were searching for, which
3358                  * is weird, but possible, so only screw with path if we didn't
3359                  * find the key and see if we have stuff that matches
3360                  */
3361                 if (ret > 0) {
3362                         ret = 0;
3363                         if (path->slots[0] == 0)
3364                                 break;
3365                         path->slots[0]--;
3366                 }
3367
3368                 /* pull out the item */
3369                 leaf = path->nodes[0];
3370                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3371
3372                 /* make sure the item matches what we want */
3373                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3374                         break;
3375                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3376                         break;
3377
3378                 /* release the path since we're done with it */
3379                 btrfs_release_path(path);
3380
3381                 /*
3382                  * this is where we are basically btrfs_lookup, without the
3383                  * crossing root thing.  we store the inode number in the
3384                  * offset of the orphan item.
3385                  */
3386
3387                 if (found_key.offset == last_objectid) {
3388                         btrfs_err(fs_info,
3389                                   "Error removing orphan entry, stopping orphan cleanup");
3390                         ret = -EINVAL;
3391                         goto out;
3392                 }
3393
3394                 last_objectid = found_key.offset;
3395
3396                 found_key.objectid = found_key.offset;
3397                 found_key.type = BTRFS_INODE_ITEM_KEY;
3398                 found_key.offset = 0;
3399                 inode = btrfs_iget(fs_info->sb, &found_key, root, NULL);
3400                 ret = PTR_ERR_OR_ZERO(inode);
3401                 if (ret && ret != -ENOENT)
3402                         goto out;
3403
3404                 if (ret == -ENOENT && root == fs_info->tree_root) {
3405                         struct btrfs_root *dead_root;
3406                         struct btrfs_fs_info *fs_info = root->fs_info;
3407                         int is_dead_root = 0;
3408
3409                         /*
3410                          * this is an orphan in the tree root. Currently these
3411                          * could come from 2 sources:
3412                          *  a) a snapshot deletion in progress
3413                          *  b) a free space cache inode
3414                          * We need to distinguish those two, as the snapshot
3415                          * orphan must not get deleted.
3416                          * find_dead_roots already ran before us, so if this
3417                          * is a snapshot deletion, we should find the root
3418                          * in the dead_roots list
3419                          */
3420                         spin_lock(&fs_info->trans_lock);
3421                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3422                                             root_list) {
3423                                 if (dead_root->root_key.objectid ==
3424                                     found_key.objectid) {
3425                                         is_dead_root = 1;
3426                                         break;
3427                                 }
3428                         }
3429                         spin_unlock(&fs_info->trans_lock);
3430                         if (is_dead_root) {
3431                                 /* prevent this orphan from being found again */
3432                                 key.offset = found_key.objectid - 1;
3433                                 continue;
3434                         }
3435
3436                 }
3437
3438                 /*
3439                  * If we have an inode with links, there are a couple of
3440                  * possibilities. Old kernels (before v3.12) used to create an
3441                  * orphan item for truncate indicating that there were possibly
3442                  * extent items past i_size that needed to be deleted. In v3.12,
3443                  * truncate was changed to update i_size in sync with the extent
3444                  * items, but the (useless) orphan item was still created. Since
3445                  * v4.18, we don't create the orphan item for truncate at all.
3446                  *
3447                  * So, this item could mean that we need to do a truncate, but
3448                  * only if this filesystem was last used on a pre-v3.12 kernel
3449                  * and was not cleanly unmounted. The odds of that are quite
3450                  * slim, and it's a pain to do the truncate now, so just delete
3451                  * the orphan item.
3452                  *
3453                  * It's also possible that this orphan item was supposed to be
3454                  * deleted but wasn't. The inode number may have been reused,
3455                  * but either way, we can delete the orphan item.
3456                  */
3457                 if (ret == -ENOENT || inode->i_nlink) {
3458                         if (!ret)
3459                                 iput(inode);
3460                         trans = btrfs_start_transaction(root, 1);
3461                         if (IS_ERR(trans)) {
3462                                 ret = PTR_ERR(trans);
3463                                 goto out;
3464                         }
3465                         btrfs_debug(fs_info, "auto deleting %Lu",
3466                                     found_key.objectid);
3467                         ret = btrfs_del_orphan_item(trans, root,
3468                                                     found_key.objectid);
3469                         btrfs_end_transaction(trans);
3470                         if (ret)
3471                                 goto out;
3472                         continue;
3473                 }
3474
3475                 nr_unlink++;
3476
3477                 /* this will do delete_inode and everything for us */
3478                 iput(inode);
3479         }
3480         /* release the path since we're done with it */
3481         btrfs_release_path(path);
3482
3483         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3484
3485         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3486                 trans = btrfs_join_transaction(root);
3487                 if (!IS_ERR(trans))
3488                         btrfs_end_transaction(trans);
3489         }
3490
3491         if (nr_unlink)
3492                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
3493
3494 out:
3495         if (ret)
3496                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
3497         btrfs_free_path(path);
3498         return ret;
3499 }
3500
3501 /*
3502  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3503  * don't find any xattrs, we know there can't be any acls.
3504  *
3505  * slot is the slot the inode is in, objectid is the objectid of the inode
3506  */
3507 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3508                                           int slot, u64 objectid,
3509                                           int *first_xattr_slot)
3510 {
3511         u32 nritems = btrfs_header_nritems(leaf);
3512         struct btrfs_key found_key;
3513         static u64 xattr_access = 0;
3514         static u64 xattr_default = 0;
3515         int scanned = 0;
3516
3517         if (!xattr_access) {
3518                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3519                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3520                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3521                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3522         }
3523
3524         slot++;
3525         *first_xattr_slot = -1;
3526         while (slot < nritems) {
3527                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3528
3529                 /* we found a different objectid, there must not be acls */
3530                 if (found_key.objectid != objectid)
3531                         return 0;
3532
3533                 /* we found an xattr, assume we've got an acl */
3534                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3535                         if (*first_xattr_slot == -1)
3536                                 *first_xattr_slot = slot;
3537                         if (found_key.offset == xattr_access ||
3538                             found_key.offset == xattr_default)
3539                                 return 1;
3540                 }
3541
3542                 /*
3543                  * we found a key greater than an xattr key, there can't
3544                  * be any acls later on
3545                  */
3546                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3547                         return 0;
3548
3549                 slot++;
3550                 scanned++;
3551
3552                 /*
3553                  * it goes inode, inode backrefs, xattrs, extents,
3554                  * so if there are a ton of hard links to an inode there can
3555                  * be a lot of backrefs.  Don't waste time searching too hard,
3556                  * this is just an optimization
3557                  */
3558                 if (scanned >= 8)
3559                         break;
3560         }
3561         /* we hit the end of the leaf before we found an xattr or
3562          * something larger than an xattr.  We have to assume the inode
3563          * has acls
3564          */
3565         if (*first_xattr_slot == -1)
3566                 *first_xattr_slot = slot;
3567         return 1;
3568 }
3569
3570 /*
3571  * read an inode from the btree into the in-memory inode
3572  */
3573 static int btrfs_read_locked_inode(struct inode *inode)
3574 {
3575         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3576         struct btrfs_path *path;
3577         struct extent_buffer *leaf;
3578         struct btrfs_inode_item *inode_item;
3579         struct btrfs_root *root = BTRFS_I(inode)->root;
3580         struct btrfs_key location;
3581         unsigned long ptr;
3582         int maybe_acls;
3583         u32 rdev;
3584         int ret;
3585         bool filled = false;
3586         int first_xattr_slot;
3587
3588         ret = btrfs_fill_inode(inode, &rdev);
3589         if (!ret)
3590                 filled = true;
3591
3592         path = btrfs_alloc_path();
3593         if (!path)
3594                 return -ENOMEM;
3595
3596         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3597
3598         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3599         if (ret) {
3600                 btrfs_free_path(path);
3601                 return ret;
3602         }
3603
3604         leaf = path->nodes[0];
3605
3606         if (filled)
3607                 goto cache_index;
3608
3609         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3610                                     struct btrfs_inode_item);
3611         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3612         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3613         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3614         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3615         btrfs_i_size_write(BTRFS_I(inode), btrfs_inode_size(leaf, inode_item));
3616
3617         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3618         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3619
3620         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3621         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3622
3623         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3624         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3625
3626         BTRFS_I(inode)->i_otime.tv_sec =
3627                 btrfs_timespec_sec(leaf, &inode_item->otime);
3628         BTRFS_I(inode)->i_otime.tv_nsec =
3629                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3630
3631         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3632         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3633         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3634
3635         inode_set_iversion_queried(inode,
3636                                    btrfs_inode_sequence(leaf, inode_item));
3637         inode->i_generation = BTRFS_I(inode)->generation;
3638         inode->i_rdev = 0;
3639         rdev = btrfs_inode_rdev(leaf, inode_item);
3640
3641         BTRFS_I(inode)->index_cnt = (u64)-1;
3642         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3643
3644 cache_index:
3645         /*
3646          * If we were modified in the current generation and evicted from memory
3647          * and then re-read we need to do a full sync since we don't have any
3648          * idea about which extents were modified before we were evicted from
3649          * cache.
3650          *
3651          * This is required for both inode re-read from disk and delayed inode
3652          * in delayed_nodes_tree.
3653          */
3654         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3655                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3656                         &BTRFS_I(inode)->runtime_flags);
3657
3658         /*
3659          * We don't persist the id of the transaction where an unlink operation
3660          * against the inode was last made. So here we assume the inode might
3661          * have been evicted, and therefore the exact value of last_unlink_trans
3662          * lost, and set it to last_trans to avoid metadata inconsistencies
3663          * between the inode and its parent if the inode is fsync'ed and the log
3664          * replayed. For example, in the scenario:
3665          *
3666          * touch mydir/foo
3667          * ln mydir/foo mydir/bar
3668          * sync
3669          * unlink mydir/bar
3670          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3671          * xfs_io -c fsync mydir/foo
3672          * <power failure>
3673          * mount fs, triggers fsync log replay
3674          *
3675          * We must make sure that when we fsync our inode foo we also log its
3676          * parent inode, otherwise after log replay the parent still has the
3677          * dentry with the "bar" name but our inode foo has a link count of 1
3678          * and doesn't have an inode ref with the name "bar" anymore.
3679          *
3680          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3681          * but it guarantees correctness at the expense of occasional full
3682          * transaction commits on fsync if our inode is a directory, or if our
3683          * inode is not a directory, logging its parent unnecessarily.
3684          */
3685         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3686
3687         path->slots[0]++;
3688         if (inode->i_nlink != 1 ||
3689             path->slots[0] >= btrfs_header_nritems(leaf))
3690                 goto cache_acl;
3691
3692         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3693         if (location.objectid != btrfs_ino(BTRFS_I(inode)))
3694                 goto cache_acl;
3695
3696         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3697         if (location.type == BTRFS_INODE_REF_KEY) {
3698                 struct btrfs_inode_ref *ref;
3699
3700                 ref = (struct btrfs_inode_ref *)ptr;
3701                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3702         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3703                 struct btrfs_inode_extref *extref;
3704
3705                 extref = (struct btrfs_inode_extref *)ptr;
3706                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3707                                                                      extref);
3708         }
3709 cache_acl:
3710         /*
3711          * try to precache a NULL acl entry for files that don't have
3712          * any xattrs or acls
3713          */
3714         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3715                         btrfs_ino(BTRFS_I(inode)), &first_xattr_slot);
3716         if (first_xattr_slot != -1) {
3717                 path->slots[0] = first_xattr_slot;
3718                 ret = btrfs_load_inode_props(inode, path);
3719                 if (ret)
3720                         btrfs_err(fs_info,
3721                                   "error loading props for ino %llu (root %llu): %d",
3722                                   btrfs_ino(BTRFS_I(inode)),
3723                                   root->root_key.objectid, ret);
3724         }
3725         btrfs_free_path(path);
3726
3727         if (!maybe_acls)
3728                 cache_no_acl(inode);
3729
3730         switch (inode->i_mode & S_IFMT) {
3731         case S_IFREG:
3732                 inode->i_mapping->a_ops = &btrfs_aops;
3733                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3734                 inode->i_fop = &btrfs_file_operations;
3735                 inode->i_op = &btrfs_file_inode_operations;
3736                 break;
3737         case S_IFDIR:
3738                 inode->i_fop = &btrfs_dir_file_operations;
3739                 inode->i_op = &btrfs_dir_inode_operations;
3740                 break;
3741         case S_IFLNK:
3742                 inode->i_op = &btrfs_symlink_inode_operations;
3743                 inode_nohighmem(inode);
3744                 inode->i_mapping->a_ops = &btrfs_aops;
3745                 break;
3746         default:
3747                 inode->i_op = &btrfs_special_inode_operations;
3748                 init_special_inode(inode, inode->i_mode, rdev);
3749                 break;
3750         }
3751
3752         btrfs_sync_inode_flags_to_i_flags(inode);
3753         return 0;
3754 }
3755
3756 /*
3757  * given a leaf and an inode, copy the inode fields into the leaf
3758  */
3759 static void fill_inode_item(struct btrfs_trans_handle *trans,
3760                             struct extent_buffer *leaf,
3761                             struct btrfs_inode_item *item,
3762                             struct inode *inode)
3763 {
3764         struct btrfs_map_token token;
3765
3766         btrfs_init_map_token(&token);
3767
3768         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3769         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3770         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3771                                    &token);
3772         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3773         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3774
3775         btrfs_set_token_timespec_sec(leaf, &item->atime,
3776                                      inode->i_atime.tv_sec, &token);
3777         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3778                                       inode->i_atime.tv_nsec, &token);
3779
3780         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3781                                      inode->i_mtime.tv_sec, &token);
3782         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3783                                       inode->i_mtime.tv_nsec, &token);
3784
3785         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3786                                      inode->i_ctime.tv_sec, &token);
3787         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3788                                       inode->i_ctime.tv_nsec, &token);
3789
3790         btrfs_set_token_timespec_sec(leaf, &item->otime,
3791                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3792         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3793                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3794
3795         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3796                                      &token);
3797         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3798                                          &token);
3799         btrfs_set_token_inode_sequence(leaf, item, inode_peek_iversion(inode),
3800                                        &token);
3801         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3802         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3803         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3804         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3805 }
3806
3807 /*
3808  * copy everything in the in-memory inode into the btree.
3809  */
3810 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3811                                 struct btrfs_root *root, struct inode *inode)
3812 {
3813         struct btrfs_inode_item *inode_item;
3814         struct btrfs_path *path;
3815         struct extent_buffer *leaf;
3816         int ret;
3817
3818         path = btrfs_alloc_path();
3819         if (!path)
3820                 return -ENOMEM;
3821
3822         path->leave_spinning = 1;
3823         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3824                                  1);
3825         if (ret) {
3826                 if (ret > 0)
3827                         ret = -ENOENT;
3828                 goto failed;
3829         }
3830
3831         leaf = path->nodes[0];
3832         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3833                                     struct btrfs_inode_item);
3834
3835         fill_inode_item(trans, leaf, inode_item, inode);
3836         btrfs_mark_buffer_dirty(leaf);
3837         btrfs_set_inode_last_trans(trans, inode);
3838         ret = 0;
3839 failed:
3840         btrfs_free_path(path);
3841         return ret;
3842 }
3843
3844 /*
3845  * copy everything in the in-memory inode into the btree.
3846  */
3847 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3848                                 struct btrfs_root *root, struct inode *inode)
3849 {
3850         struct btrfs_fs_info *fs_info = root->fs_info;
3851         int ret;
3852
3853         /*
3854          * If the inode is a free space inode, we can deadlock during commit
3855          * if we put it into the delayed code.
3856          *
3857          * The data relocation inode should also be directly updated
3858          * without delay
3859          */
3860         if (!btrfs_is_free_space_inode(BTRFS_I(inode))
3861             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3862             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3863                 btrfs_update_root_times(trans, root);
3864
3865                 ret = btrfs_delayed_update_inode(trans, root, inode);
3866                 if (!ret)
3867                         btrfs_set_inode_last_trans(trans, inode);
3868                 return ret;
3869         }
3870
3871         return btrfs_update_inode_item(trans, root, inode);
3872 }
3873
3874 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3875                                          struct btrfs_root *root,
3876                                          struct inode *inode)
3877 {
3878         int ret;
3879
3880         ret = btrfs_update_inode(trans, root, inode);
3881         if (ret == -ENOSPC)
3882                 return btrfs_update_inode_item(trans, root, inode);
3883         return ret;
3884 }
3885
3886 /*
3887  * unlink helper that gets used here in inode.c and in the tree logging
3888  * recovery code.  It remove a link in a directory with a given name, and
3889  * also drops the back refs in the inode to the directory
3890  */
3891 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3892                                 struct btrfs_root *root,
3893                                 struct btrfs_inode *dir,
3894                                 struct btrfs_inode *inode,
3895                                 const char *name, int name_len)
3896 {
3897         struct btrfs_fs_info *fs_info = root->fs_info;
3898         struct btrfs_path *path;
3899         int ret = 0;
3900         struct extent_buffer *leaf;
3901         struct btrfs_dir_item *di;
3902         struct btrfs_key key;
3903         u64 index;
3904         u64 ino = btrfs_ino(inode);
3905         u64 dir_ino = btrfs_ino(dir);
3906
3907         path = btrfs_alloc_path();
3908         if (!path) {
3909                 ret = -ENOMEM;
3910                 goto out;
3911         }
3912
3913         path->leave_spinning = 1;
3914         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3915                                     name, name_len, -1);
3916         if (IS_ERR_OR_NULL(di)) {
3917                 ret = di ? PTR_ERR(di) : -ENOENT;
3918                 goto err;
3919         }
3920         leaf = path->nodes[0];
3921         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3922         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3923         if (ret)
3924                 goto err;
3925         btrfs_release_path(path);
3926
3927         /*
3928          * If we don't have dir index, we have to get it by looking up
3929          * the inode ref, since we get the inode ref, remove it directly,
3930          * it is unnecessary to do delayed deletion.
3931          *
3932          * But if we have dir index, needn't search inode ref to get it.
3933          * Since the inode ref is close to the inode item, it is better
3934          * that we delay to delete it, and just do this deletion when
3935          * we update the inode item.
3936          */
3937         if (inode->dir_index) {
3938                 ret = btrfs_delayed_delete_inode_ref(inode);
3939                 if (!ret) {
3940                         index = inode->dir_index;
3941                         goto skip_backref;
3942                 }
3943         }
3944
3945         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3946                                   dir_ino, &index);
3947         if (ret) {
3948                 btrfs_info(fs_info,
3949                         "failed to delete reference to %.*s, inode %llu parent %llu",
3950                         name_len, name, ino, dir_ino);
3951                 btrfs_abort_transaction(trans, ret);
3952                 goto err;
3953         }
3954 skip_backref:
3955         ret = btrfs_delete_delayed_dir_index(trans, dir, index);
3956         if (ret) {
3957                 btrfs_abort_transaction(trans, ret);
3958                 goto err;
3959         }
3960
3961         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
3962                         dir_ino);
3963         if (ret != 0 && ret != -ENOENT) {
3964                 btrfs_abort_transaction(trans, ret);
3965                 goto err;
3966         }
3967
3968         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
3969                         index);
3970         if (ret == -ENOENT)
3971                 ret = 0;
3972         else if (ret)
3973                 btrfs_abort_transaction(trans, ret);
3974 err:
3975         btrfs_free_path(path);
3976         if (ret)
3977                 goto out;
3978
3979         btrfs_i_size_write(dir, dir->vfs_inode.i_size - name_len * 2);
3980         inode_inc_iversion(&inode->vfs_inode);
3981         inode_inc_iversion(&dir->vfs_inode);
3982         inode->vfs_inode.i_ctime = dir->vfs_inode.i_mtime =
3983                 dir->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
3984         ret = btrfs_update_inode(trans, root, &dir->vfs_inode);
3985 out:
3986         return ret;
3987 }
3988
3989 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3990                        struct btrfs_root *root,
3991                        struct btrfs_inode *dir, struct btrfs_inode *inode,
3992                        const char *name, int name_len)
3993 {
3994         int ret;
3995         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3996         if (!ret) {
3997                 drop_nlink(&inode->vfs_inode);
3998                 ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
3999         }
4000         return ret;
4001 }
4002
4003 /*
4004  * helper to start transaction for unlink and rmdir.
4005  *
4006  * unlink and rmdir are special in btrfs, they do not always free space, so
4007  * if we cannot make our reservations the normal way try and see if there is
4008  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4009  * allow the unlink to occur.
4010  */
4011 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4012 {
4013         struct btrfs_root *root = BTRFS_I(dir)->root;
4014
4015         /*
4016          * 1 for the possible orphan item
4017          * 1 for the dir item
4018          * 1 for the dir index
4019          * 1 for the inode ref
4020          * 1 for the inode
4021          */
4022         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4023 }
4024
4025 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4026 {
4027         struct btrfs_root *root = BTRFS_I(dir)->root;
4028         struct btrfs_trans_handle *trans;
4029         struct inode *inode = d_inode(dentry);
4030         int ret;
4031
4032         trans = __unlink_start_trans(dir);
4033         if (IS_ERR(trans))
4034                 return PTR_ERR(trans);
4035
4036         btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
4037                         0);
4038
4039         ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4040                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4041                         dentry->d_name.len);
4042         if (ret)
4043                 goto out;
4044
4045         if (inode->i_nlink == 0) {
4046                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
4047                 if (ret)
4048                         goto out;
4049         }
4050
4051 out:
4052         btrfs_end_transaction(trans);
4053         btrfs_btree_balance_dirty(root->fs_info);
4054         return ret;
4055 }
4056
4057 static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4058                                struct inode *dir, u64 objectid,
4059                                const char *name, int name_len)
4060 {
4061         struct btrfs_root *root = BTRFS_I(dir)->root;
4062         struct btrfs_path *path;
4063         struct extent_buffer *leaf;
4064         struct btrfs_dir_item *di;
4065         struct btrfs_key key;
4066         u64 index;
4067         int ret;
4068         u64 dir_ino = btrfs_ino(BTRFS_I(dir));
4069
4070         path = btrfs_alloc_path();
4071         if (!path)
4072                 return -ENOMEM;
4073
4074         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4075                                    name, name_len, -1);
4076         if (IS_ERR_OR_NULL(di)) {
4077                 ret = di ? PTR_ERR(di) : -ENOENT;
4078                 goto out;
4079         }
4080
4081         leaf = path->nodes[0];
4082         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4083         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4084         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4085         if (ret) {
4086                 btrfs_abort_transaction(trans, ret);
4087                 goto out;
4088         }
4089         btrfs_release_path(path);
4090
4091         ret = btrfs_del_root_ref(trans, objectid, root->root_key.objectid,
4092                                  dir_ino, &index, name, name_len);
4093         if (ret < 0) {
4094                 if (ret != -ENOENT) {
4095                         btrfs_abort_transaction(trans, ret);
4096                         goto out;
4097                 }
4098                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4099                                                  name, name_len);
4100                 if (IS_ERR_OR_NULL(di)) {
4101                         if (!di)
4102                                 ret = -ENOENT;
4103                         else
4104                                 ret = PTR_ERR(di);
4105                         btrfs_abort_transaction(trans, ret);
4106                         goto out;
4107                 }
4108
4109                 leaf = path->nodes[0];
4110                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4111                 index = key.offset;
4112         }
4113         btrfs_release_path(path);
4114
4115         ret = btrfs_delete_delayed_dir_index(trans, BTRFS_I(dir), index);
4116         if (ret) {
4117                 btrfs_abort_transaction(trans, ret);
4118                 goto out;
4119         }
4120
4121         btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name_len * 2);
4122         inode_inc_iversion(dir);
4123         dir->i_mtime = dir->i_ctime = current_time(dir);
4124         ret = btrfs_update_inode_fallback(trans, root, dir);
4125         if (ret)
4126                 btrfs_abort_transaction(trans, ret);
4127 out:
4128         btrfs_free_path(path);
4129         return ret;
4130 }
4131
4132 /*
4133  * Helper to check if the subvolume references other subvolumes or if it's
4134  * default.
4135  */
4136 static noinline int may_destroy_subvol(struct btrfs_root *root)
4137 {
4138         struct btrfs_fs_info *fs_info = root->fs_info;
4139         struct btrfs_path *path;
4140         struct btrfs_dir_item *di;
4141         struct btrfs_key key;
4142         u64 dir_id;
4143         int ret;
4144
4145         path = btrfs_alloc_path();
4146         if (!path)
4147                 return -ENOMEM;
4148
4149         /* Make sure this root isn't set as the default subvol */
4150         dir_id = btrfs_super_root_dir(fs_info->super_copy);
4151         di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
4152                                    dir_id, "default", 7, 0);
4153         if (di && !IS_ERR(di)) {
4154                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
4155                 if (key.objectid == root->root_key.objectid) {
4156                         ret = -EPERM;
4157                         btrfs_err(fs_info,
4158                                   "deleting default subvolume %llu is not allowed",
4159                                   key.objectid);
4160                         goto out;
4161                 }
4162                 btrfs_release_path(path);
4163         }
4164
4165         key.objectid = root->root_key.objectid;
4166         key.type = BTRFS_ROOT_REF_KEY;
4167         key.offset = (u64)-1;
4168
4169         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
4170         if (ret < 0)
4171                 goto out;
4172         BUG_ON(ret == 0);
4173
4174         ret = 0;
4175         if (path->slots[0] > 0) {
4176                 path->slots[0]--;
4177                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
4178                 if (key.objectid == root->root_key.objectid &&
4179                     key.type == BTRFS_ROOT_REF_KEY)
4180                         ret = -ENOTEMPTY;
4181         }
4182 out:
4183         btrfs_free_path(path);
4184         return ret;
4185 }
4186
4187 /* Delete all dentries for inodes belonging to the root */
4188 static void btrfs_prune_dentries(struct btrfs_root *root)
4189 {
4190         struct btrfs_fs_info *fs_info = root->fs_info;
4191         struct rb_node *node;
4192         struct rb_node *prev;
4193         struct btrfs_inode *entry;
4194         struct inode *inode;
4195         u64 objectid = 0;
4196
4197         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
4198                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4199
4200         spin_lock(&root->inode_lock);
4201 again:
4202         node = root->inode_tree.rb_node;
4203         prev = NULL;
4204         while (node) {
4205                 prev = node;
4206                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4207
4208                 if (objectid < btrfs_ino(entry))
4209                         node = node->rb_left;
4210                 else if (objectid > btrfs_ino(entry))
4211                         node = node->rb_right;
4212                 else
4213                         break;
4214         }
4215         if (!node) {
4216                 while (prev) {
4217                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4218                         if (objectid <= btrfs_ino(entry)) {
4219                                 node = prev;
4220                                 break;
4221                         }
4222                         prev = rb_next(prev);
4223                 }
4224         }
4225         while (node) {
4226                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4227                 objectid = btrfs_ino(entry) + 1;
4228                 inode = igrab(&entry->vfs_inode);
4229                 if (inode) {
4230                         spin_unlock(&root->inode_lock);
4231                         if (atomic_read(&inode->i_count) > 1)
4232                                 d_prune_aliases(inode);
4233                         /*
4234                          * btrfs_drop_inode will have it removed from the inode
4235                          * cache when its usage count hits zero.
4236                          */
4237                         iput(inode);
4238                         cond_resched();
4239                         spin_lock(&root->inode_lock);
4240                         goto again;
4241                 }
4242
4243                 if (cond_resched_lock(&root->inode_lock))
4244                         goto again;
4245
4246                 node = rb_next(node);
4247         }
4248         spin_unlock(&root->inode_lock);
4249 }
4250
4251 int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
4252 {
4253         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
4254         struct btrfs_root *root = BTRFS_I(dir)->root;
4255         struct inode *inode = d_inode(dentry);
4256         struct btrfs_root *dest = BTRFS_I(inode)->root;
4257         struct btrfs_trans_handle *trans;
4258         struct btrfs_block_rsv block_rsv;
4259         u64 root_flags;
4260         int ret;
4261         int err;
4262
4263         /*
4264          * Don't allow to delete a subvolume with send in progress. This is
4265          * inside the inode lock so the error handling that has to drop the bit
4266          * again is not run concurrently.
4267          */
4268         spin_lock(&dest->root_item_lock);
4269         if (dest->send_in_progress) {
4270                 spin_unlock(&dest->root_item_lock);
4271                 btrfs_warn(fs_info,
4272                            "attempt to delete subvolume %llu during send",
4273                            dest->root_key.objectid);
4274                 return -EPERM;
4275         }
4276         root_flags = btrfs_root_flags(&dest->root_item);
4277         btrfs_set_root_flags(&dest->root_item,
4278                              root_flags | BTRFS_ROOT_SUBVOL_DEAD);
4279         spin_unlock(&dest->root_item_lock);
4280
4281         down_write(&fs_info->subvol_sem);
4282
4283         err = may_destroy_subvol(dest);
4284         if (err)
4285                 goto out_up_write;
4286
4287         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
4288         /*
4289          * One for dir inode,
4290          * two for dir entries,
4291          * two for root ref/backref.
4292          */
4293         err = btrfs_subvolume_reserve_metadata(root, &block_rsv, 5, true);
4294         if (err)
4295                 goto out_up_write;
4296
4297         trans = btrfs_start_transaction(root, 0);
4298         if (IS_ERR(trans)) {
4299                 err = PTR_ERR(trans);
4300                 goto out_release;
4301         }
4302         trans->block_rsv = &block_rsv;
4303         trans->bytes_reserved = block_rsv.size;
4304
4305         btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
4306
4307         ret = btrfs_unlink_subvol(trans, dir, dest->root_key.objectid,
4308                                   dentry->d_name.name, dentry->d_name.len);
4309         if (ret) {
4310                 err = ret;
4311                 btrfs_abort_transaction(trans, ret);
4312                 goto out_end_trans;
4313         }
4314
4315         btrfs_record_root_in_trans(trans, dest);
4316
4317         memset(&dest->root_item.drop_progress, 0,
4318                 sizeof(dest->root_item.drop_progress));
4319         dest->root_item.drop_level = 0;
4320         btrfs_set_root_refs(&dest->root_item, 0);
4321
4322         if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
4323                 ret = btrfs_insert_orphan_item(trans,
4324                                         fs_info->tree_root,
4325                                         dest->root_key.objectid);
4326                 if (ret) {
4327                         btrfs_abort_transaction(trans, ret);
4328                         err = ret;
4329                         goto out_end_trans;
4330                 }
4331         }
4332
4333         ret = btrfs_uuid_tree_remove(trans, dest->root_item.uuid,
4334                                   BTRFS_UUID_KEY_SUBVOL,
4335                                   dest->root_key.objectid);
4336         if (ret && ret != -ENOENT) {
4337                 btrfs_abort_transaction(trans, ret);
4338                 err = ret;
4339                 goto out_end_trans;
4340         }
4341         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
4342                 ret = btrfs_uuid_tree_remove(trans,
4343                                           dest->root_item.received_uuid,
4344                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4345                                           dest->root_key.objectid);
4346                 if (ret && ret != -ENOENT) {
4347                         btrfs_abort_transaction(trans, ret);
4348                         err = ret;
4349                         goto out_end_trans;
4350                 }
4351         }
4352
4353 out_end_trans:
4354         trans->block_rsv = NULL;
4355         trans->bytes_reserved = 0;
4356         ret = btrfs_end_transaction(trans);
4357         if (ret && !err)
4358                 err = ret;
4359         inode->i_flags |= S_DEAD;
4360 out_release:
4361         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
4362 out_up_write:
4363         up_write(&fs_info->subvol_sem);
4364         if (err) {
4365                 spin_lock(&dest->root_item_lock);
4366                 root_flags = btrfs_root_flags(&dest->root_item);
4367                 btrfs_set_root_flags(&dest->root_item,
4368                                 root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
4369                 spin_unlock(&dest->root_item_lock);
4370         } else {
4371                 d_invalidate(dentry);
4372                 btrfs_prune_dentries(dest);
4373                 ASSERT(dest->send_in_progress == 0);
4374
4375                 /* the last ref */
4376                 if (dest->ino_cache_inode) {
4377                         iput(dest->ino_cache_inode);
4378                         dest->ino_cache_inode = NULL;
4379                 }
4380         }
4381
4382         return err;
4383 }
4384
4385 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4386 {
4387         struct inode *inode = d_inode(dentry);
4388         int err = 0;
4389         struct btrfs_root *root = BTRFS_I(dir)->root;
4390         struct btrfs_trans_handle *trans;
4391         u64 last_unlink_trans;
4392
4393         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4394                 return -ENOTEMPTY;
4395         if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID)
4396                 return btrfs_delete_subvolume(dir, dentry);
4397
4398         trans = __unlink_start_trans(dir);
4399         if (IS_ERR(trans))
4400                 return PTR_ERR(trans);
4401
4402         if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4403                 err = btrfs_unlink_subvol(trans, dir,
4404                                           BTRFS_I(inode)->location.objectid,
4405                                           dentry->d_name.name,
4406                                           dentry->d_name.len);
4407                 goto out;
4408         }
4409
4410         err = btrfs_orphan_add(trans, BTRFS_I(inode));
4411         if (err)
4412                 goto out;
4413
4414         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
4415
4416         /* now the directory is empty */
4417         err = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
4418                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
4419                         dentry->d_name.len);
4420         if (!err) {
4421                 btrfs_i_size_write(BTRFS_I(inode), 0);
4422                 /*
4423                  * Propagate the last_unlink_trans value of the deleted dir to
4424                  * its parent directory. This is to prevent an unrecoverable
4425                  * log tree in the case we do something like this:
4426                  * 1) create dir foo
4427                  * 2) create snapshot under dir foo
4428                  * 3) delete the snapshot
4429                  * 4) rmdir foo
4430                  * 5) mkdir foo
4431                  * 6) fsync foo or some file inside foo
4432                  */
4433                 if (last_unlink_trans >= trans->transid)
4434                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
4435         }
4436 out:
4437         btrfs_end_transaction(trans);
4438         btrfs_btree_balance_dirty(root->fs_info);
4439
4440         return err;
4441 }
4442
4443 static int truncate_space_check(struct btrfs_trans_handle *trans,
4444                                 struct btrfs_root *root,
4445                                 u64 bytes_deleted)
4446 {
4447         struct btrfs_fs_info *fs_info = root->fs_info;
4448         int ret;
4449
4450         /*
4451          * This is only used to apply pressure to the enospc system, we don't
4452          * intend to use this reservation at all.
4453          */
4454         bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
4455         bytes_deleted *= fs_info->nodesize;
4456         ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
4457                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4458         if (!ret) {
4459                 trace_btrfs_space_reservation(fs_info, "transaction",
4460                                               trans->transid,
4461                                               bytes_deleted, 1);
4462                 trans->bytes_reserved += bytes_deleted;
4463         }
4464         return ret;
4465
4466 }
4467
4468 /*
4469  * Return this if we need to call truncate_block for the last bit of the
4470  * truncate.
4471  */
4472 #define NEED_TRUNCATE_BLOCK 1
4473
4474 /*
4475  * this can truncate away extent items, csum items and directory items.
4476  * It starts at a high offset and removes keys until it can't find
4477  * any higher than new_size
4478  *
4479  * csum items that cross the new i_size are truncated to the new size
4480  * as well.
4481  *
4482  * min_type is the minimum key type to truncate down to.  If set to 0, this
4483  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4484  */
4485 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4486                                struct btrfs_root *root,
4487                                struct inode *inode,
4488                                u64 new_size, u32 min_type)
4489 {
4490         struct btrfs_fs_info *fs_info = root->fs_info;
4491         struct btrfs_path *path;
4492         struct extent_buffer *leaf;
4493         struct btrfs_file_extent_item *fi;
4494         struct btrfs_key key;
4495         struct btrfs_key found_key;
4496         u64 extent_start = 0;
4497         u64 extent_num_bytes = 0;
4498         u64 extent_offset = 0;
4499         u64 item_end = 0;
4500         u64 last_size = new_size;
4501         u32 found_type = (u8)-1;
4502         int found_extent;
4503         int del_item;
4504         int pending_del_nr = 0;
4505         int pending_del_slot = 0;
4506         int extent_type = -1;
4507         int ret;
4508         u64 ino = btrfs_ino(BTRFS_I(inode));
4509         u64 bytes_deleted = 0;
4510         bool be_nice = false;
4511         bool should_throttle = false;
4512         bool should_end = false;
4513
4514         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4515
4516         /*
4517          * for non-free space inodes and ref cows, we want to back off from
4518          * time to time
4519          */
4520         if (!btrfs_is_free_space_inode(BTRFS_I(inode)) &&
4521             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4522                 be_nice = true;
4523
4524         path = btrfs_alloc_path();
4525         if (!path)
4526                 return -ENOMEM;
4527         path->reada = READA_BACK;
4528
4529         /*
4530          * We want to drop from the next block forward in case this new size is
4531          * not block aligned since we will be keeping the last block of the
4532          * extent just the way it is.
4533          */
4534         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4535             root == fs_info->tree_root)
4536                 btrfs_drop_extent_cache(BTRFS_I(inode), ALIGN(new_size,
4537                                         fs_info->sectorsize),
4538                                         (u64)-1, 0);
4539
4540         /*
4541          * This function is also used to drop the items in the log tree before
4542          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4543          * it is used to drop the loged items. So we shouldn't kill the delayed
4544          * items.
4545          */
4546         if (min_type == 0 && root == BTRFS_I(inode)->root)
4547                 btrfs_kill_delayed_inode_items(BTRFS_I(inode));
4548
4549         key.objectid = ino;
4550         key.offset = (u64)-1;
4551         key.type = (u8)-1;
4552
4553 search_again:
4554         /*
4555          * with a 16K leaf size and 128MB extents, you can actually queue
4556          * up a huge file in a single leaf.  Most of the time that
4557          * bytes_deleted is > 0, it will be huge by the time we get here
4558          */
4559         if (be_nice && bytes_deleted > SZ_32M &&
4560             btrfs_should_end_transaction(trans)) {
4561                 ret = -EAGAIN;
4562                 goto out;
4563         }
4564
4565         path->leave_spinning = 1;
4566         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4567         if (ret < 0)
4568                 goto out;
4569
4570         if (ret > 0) {
4571                 ret = 0;
4572                 /* there are no items in the tree for us to truncate, we're
4573                  * done
4574                  */
4575                 if (path->slots[0] == 0)
4576                         goto out;
4577                 path->slots[0]--;
4578         }
4579
4580         while (1) {
4581                 fi = NULL;
4582                 leaf = path->nodes[0];
4583                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4584                 found_type = found_key.type;
4585
4586                 if (found_key.objectid != ino)
4587                         break;
4588
4589                 if (found_type < min_type)
4590                         break;
4591
4592                 item_end = found_key.offset;
4593                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4594                         fi = btrfs_item_ptr(leaf, path->slots[0],
4595                                             struct btrfs_file_extent_item);
4596                         extent_type = btrfs_file_extent_type(leaf, fi);
4597                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4598                                 item_end +=
4599                                     btrfs_file_extent_num_bytes(leaf, fi);
4600
4601                                 trace_btrfs_truncate_show_fi_regular(
4602                                         BTRFS_I(inode), leaf, fi,
4603                                         found_key.offset);
4604                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4605                                 item_end += btrfs_file_extent_ram_bytes(leaf,
4606                                                                         fi);
4607
4608                                 trace_btrfs_truncate_show_fi_inline(
4609                                         BTRFS_I(inode), leaf, fi, path->slots[0],
4610                                         found_key.offset);
4611                         }
4612                         item_end--;
4613                 }
4614                 if (found_type > min_type) {
4615                         del_item = 1;
4616                 } else {
4617                         if (item_end < new_size)
4618                                 break;
4619                         if (found_key.offset >= new_size)
4620                                 del_item = 1;
4621                         else
4622                                 del_item = 0;
4623                 }
4624                 found_extent = 0;
4625                 /* FIXME, shrink the extent if the ref count is only 1 */
4626                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4627                         goto delete;
4628
4629                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4630                         u64 num_dec;
4631                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4632                         if (!del_item) {
4633                                 u64 orig_num_bytes =
4634                                         btrfs_file_extent_num_bytes(leaf, fi);
4635                                 extent_num_bytes = ALIGN(new_size -
4636                                                 found_key.offset,
4637                                                 fs_info->sectorsize);
4638                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4639                                                          extent_num_bytes);
4640                                 num_dec = (orig_num_bytes -
4641                                            extent_num_bytes);
4642                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4643                                              &root->state) &&
4644                                     extent_start != 0)
4645                                         inode_sub_bytes(inode, num_dec);
4646                                 btrfs_mark_buffer_dirty(leaf);
4647                         } else {
4648                                 extent_num_bytes =
4649                                         btrfs_file_extent_disk_num_bytes(leaf,
4650                                                                          fi);
4651                                 extent_offset = found_key.offset -
4652                                         btrfs_file_extent_offset(leaf, fi);
4653
4654                                 /* FIXME blocksize != 4096 */
4655                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4656                                 if (extent_start != 0) {
4657                                         found_extent = 1;
4658                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4659                                                      &root->state))
4660                                                 inode_sub_bytes(inode, num_dec);
4661                                 }
4662                         }
4663                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4664                         /*
4665                          * we can't truncate inline items that have had
4666                          * special encodings
4667                          */
4668                         if (!del_item &&
4669                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4670                             btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
4671                             btrfs_file_extent_compression(leaf, fi) == 0) {
4672                                 u32 size = (u32)(new_size - found_key.offset);
4673
4674                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4675                                 size = btrfs_file_extent_calc_inline_size(size);
4676                                 btrfs_truncate_item(root->fs_info, path, size, 1);
4677                         } else if (!del_item) {
4678                                 /*
4679                                  * We have to bail so the last_size is set to
4680                                  * just before this extent.
4681                                  */
4682                                 ret = NEED_TRUNCATE_BLOCK;
4683                                 break;
4684                         }
4685
4686                         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4687                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4688                 }
4689 delete:
4690                 if (del_item)
4691                         last_size = found_key.offset;
4692                 else
4693                         last_size = new_size;
4694                 if (del_item) {
4695                         if (!pending_del_nr) {
4696                                 /* no pending yet, add ourselves */
4697                                 pending_del_slot = path->slots[0];
4698                                 pending_del_nr = 1;
4699                         } else if (pending_del_nr &&
4700                                    path->slots[0] + 1 == pending_del_slot) {
4701                                 /* hop on the pending chunk */
4702                                 pending_del_nr++;
4703                                 pending_del_slot = path->slots[0];
4704                         } else {
4705                                 BUG();
4706                         }
4707                 } else {
4708                         break;
4709                 }
4710                 should_throttle = false;
4711
4712                 if (found_extent &&
4713                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4714                      root == fs_info->tree_root)) {
4715                         btrfs_set_path_blocking(path);
4716                         bytes_deleted += extent_num_bytes;
4717                         ret = btrfs_free_extent(trans, root, extent_start,
4718                                                 extent_num_bytes, 0,
4719                                                 btrfs_header_owner(leaf),
4720                                                 ino, extent_offset);
4721                         if (ret) {
4722                                 btrfs_abort_transaction(trans, ret);
4723                                 break;
4724                         }
4725                         if (btrfs_should_throttle_delayed_refs(trans))
4726                                 btrfs_async_run_delayed_refs(fs_info,
4727                                         trans->delayed_ref_updates * 2,
4728                                         trans->transid, 0);
4729                         if (be_nice) {
4730                                 if (truncate_space_check(trans, root,
4731                                                          extent_num_bytes)) {
4732                                         should_end = true;
4733                                 }
4734                                 if (btrfs_should_throttle_delayed_refs(trans))
4735                                         should_throttle = true;
4736                         }
4737                 }
4738
4739                 if (found_type == BTRFS_INODE_ITEM_KEY)
4740                         break;
4741
4742                 if (path->slots[0] == 0 ||
4743                     path->slots[0] != pending_del_slot ||
4744                     should_throttle || should_end) {
4745                         if (pending_del_nr) {
4746                                 ret = btrfs_del_items(trans, root, path,
4747                                                 pending_del_slot,
4748                                                 pending_del_nr);
4749                                 if (ret) {
4750                                         btrfs_abort_transaction(trans, ret);
4751                                         break;
4752                                 }
4753                                 pending_del_nr = 0;
4754                         }
4755                         btrfs_release_path(path);
4756                         if (should_throttle) {
4757                                 unsigned long updates = trans->delayed_ref_updates;
4758                                 if (updates) {
4759                                         trans->delayed_ref_updates = 0;
4760                                         ret = btrfs_run_delayed_refs(trans,
4761                                                                    updates * 2);
4762                                         if (ret)
4763                                                 break;
4764                                 }
4765                         }
4766                         /*
4767                          * if we failed to refill our space rsv, bail out
4768                          * and let the transaction restart
4769                          */
4770                         if (should_end) {
4771                                 ret = -EAGAIN;
4772                                 break;
4773                         }
4774                         goto search_again;
4775                 } else {
4776                         path->slots[0]--;
4777                 }
4778         }
4779 out:
4780         if (ret >= 0 && pending_del_nr) {
4781                 int err;
4782
4783                 err = btrfs_del_items(trans, root, path, pending_del_slot,
4784                                       pending_del_nr);
4785                 if (err) {
4786                         btrfs_abort_transaction(trans, err);
4787                         ret = err;
4788                 }
4789         }
4790         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4791                 ASSERT(last_size >= new_size);
4792                 if (!ret && last_size > new_size)
4793                         last_size = new_size;
4794                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4795         }
4796
4797         btrfs_free_path(path);
4798
4799         if (be_nice && bytes_deleted > SZ_32M && (ret >= 0 || ret == -EAGAIN)) {
4800                 unsigned long updates = trans->delayed_ref_updates;
4801                 int err;
4802
4803                 if (updates) {
4804                         trans->delayed_ref_updates = 0;
4805                         err = btrfs_run_delayed_refs(trans, updates * 2);
4806                         if (err)
4807                                 ret = err;
4808                 }
4809         }
4810         return ret;
4811 }
4812
4813 /*
4814  * btrfs_truncate_block - read, zero a chunk and write a block
4815  * @inode - inode that we're zeroing
4816  * @from - the offset to start zeroing
4817  * @len - the length to zero, 0 to zero the entire range respective to the
4818  *      offset
4819  * @front - zero up to the offset instead of from the offset on
4820  *
4821  * This will find the block for the "from" offset and cow the block and zero the
4822  * part we want to zero.  This is used with truncate and hole punching.
4823  */
4824 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4825                         int front)
4826 {
4827         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4828         struct address_space *mapping = inode->i_mapping;
4829         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4830         struct btrfs_ordered_extent *ordered;
4831         struct extent_state *cached_state = NULL;
4832         struct extent_changeset *data_reserved = NULL;
4833         char *kaddr;
4834         u32 blocksize = fs_info->sectorsize;
4835         pgoff_t index = from >> PAGE_SHIFT;
4836         unsigned offset = from & (blocksize - 1);
4837         struct page *page;
4838         gfp_t mask = btrfs_alloc_write_mask(mapping);
4839         int ret = 0;
4840         u64 block_start;
4841         u64 block_end;
4842
4843         if (IS_ALIGNED(offset, blocksize) &&
4844             (!len || IS_ALIGNED(len, blocksize)))
4845                 goto out;
4846
4847         block_start = round_down(from, blocksize);
4848         block_end = block_start + blocksize - 1;
4849
4850         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
4851                                            block_start, blocksize);
4852         if (ret)
4853                 goto out;
4854
4855 again:
4856         page = find_or_create_page(mapping, index, mask);
4857         if (!page) {
4858                 btrfs_delalloc_release_space(inode, data_reserved,
4859                                              block_start, blocksize, true);
4860                 btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
4861                 ret = -ENOMEM;
4862                 goto out;
4863         }
4864
4865         if (!PageUptodate(page)) {
4866                 ret = btrfs_readpage(NULL, page);
4867                 lock_page(page);
4868                 if (page->mapping != mapping) {
4869                         unlock_page(page);
4870                         put_page(page);
4871                         goto again;
4872                 }
4873                 if (!PageUptodate(page)) {
4874                         ret = -EIO;
4875                         goto out_unlock;
4876                 }
4877         }
4878         wait_on_page_writeback(page);
4879
4880         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4881         set_page_extent_mapped(page);
4882
4883         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4884         if (ordered) {
4885                 unlock_extent_cached(io_tree, block_start, block_end,
4886                                      &cached_state);
4887                 unlock_page(page);
4888                 put_page(page);
4889                 btrfs_start_ordered_extent(inode, ordered, 1);
4890                 btrfs_put_ordered_extent(ordered);
4891                 goto again;
4892         }
4893
4894         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4895                           EXTENT_DIRTY | EXTENT_DELALLOC |
4896                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4897                           0, 0, &cached_state);
4898
4899         ret = btrfs_set_extent_delalloc(inode, block_start, block_end, 0,
4900                                         &cached_state, 0);
4901         if (ret) {
4902                 unlock_extent_cached(io_tree, block_start, block_end,
4903                                      &cached_state);
4904                 goto out_unlock;
4905         }
4906
4907         if (offset != blocksize) {
4908                 if (!len)
4909                         len = blocksize - offset;
4910                 kaddr = kmap(page);
4911                 if (front)
4912                         memset(kaddr + (block_start - page_offset(page)),
4913                                 0, offset);
4914                 else
4915                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4916                                 0, len);
4917                 flush_dcache_page(page);
4918                 kunmap(page);
4919         }
4920         ClearPageChecked(page);
4921         set_page_dirty(page);
4922         unlock_extent_cached(io_tree, block_start, block_end, &cached_state);
4923
4924 out_unlock:
4925         if (ret)
4926                 btrfs_delalloc_release_space(inode, data_reserved, block_start,
4927                                              blocksize, true);
4928         btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0));
4929         unlock_page(page);
4930         put_page(page);
4931 out:
4932         extent_changeset_free(data_reserved);
4933         return ret;
4934 }
4935
4936 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4937                              u64 offset, u64 len)
4938 {
4939         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4940         struct btrfs_trans_handle *trans;
4941         int ret;
4942
4943         /*
4944          * Still need to make sure the inode looks like it's been updated so
4945          * that any holes get logged if we fsync.
4946          */
4947         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4948                 BTRFS_I(inode)->last_trans = fs_info->generation;
4949                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4950                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4951                 return 0;
4952         }
4953
4954         /*
4955          * 1 - for the one we're dropping
4956          * 1 - for the one we're adding
4957          * 1 - for updating the inode.
4958          */
4959         trans = btrfs_start_transaction(root, 3);
4960         if (IS_ERR(trans))
4961                 return PTR_ERR(trans);
4962
4963         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4964         if (ret) {
4965                 btrfs_abort_transaction(trans, ret);
4966                 btrfs_end_transaction(trans);
4967                 return ret;
4968         }
4969
4970         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(BTRFS_I(inode)),
4971                         offset, 0, 0, len, 0, len, 0, 0, 0);
4972         if (ret)
4973                 btrfs_abort_transaction(trans, ret);
4974         else
4975                 btrfs_update_inode(trans, root, inode);
4976         btrfs_end_transaction(trans);
4977         return ret;
4978 }
4979
4980 /*
4981  * This function puts in dummy file extents for the area we're creating a hole
4982  * for.  So if we are truncating this file to a larger size we need to insert
4983  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4984  * the range between oldsize and size
4985  */
4986 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4987 {
4988         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4989         struct btrfs_root *root = BTRFS_I(inode)->root;
4990         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4991         struct extent_map *em = NULL;
4992         struct extent_state *cached_state = NULL;
4993         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4994         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
4995         u64 block_end = ALIGN(size, fs_info->sectorsize);
4996         u64 last_byte;
4997         u64 cur_offset;
4998         u64 hole_size;
4999         int err = 0;
5000
5001         /*
5002          * If our size started in the middle of a block we need to zero out the
5003          * rest of the block before we expand the i_size, otherwise we could
5004          * expose stale data.
5005          */
5006         err = btrfs_truncate_block(inode, oldsize, 0, 0);
5007         if (err)
5008                 return err;
5009
5010         if (size <= hole_start)
5011                 return 0;
5012
5013         while (1) {
5014                 struct btrfs_ordered_extent *ordered;
5015
5016                 lock_extent_bits(io_tree, hole_start, block_end - 1,
5017                                  &cached_state);
5018                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), hole_start,
5019                                                      block_end - hole_start);
5020                 if (!ordered)
5021                         break;
5022                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
5023                                      &cached_state);
5024                 btrfs_start_ordered_extent(inode, ordered, 1);
5025                 btrfs_put_ordered_extent(ordered);
5026         }
5027
5028         cur_offset = hole_start;
5029         while (1) {
5030                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
5031                                 block_end - cur_offset, 0);
5032                 if (IS_ERR(em)) {
5033                         err = PTR_ERR(em);
5034                         em = NULL;
5035                         break;
5036                 }
5037                 last_byte = min(extent_map_end(em), block_end);
5038                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
5039                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
5040                         struct extent_map *hole_em;
5041                         hole_size = last_byte - cur_offset;
5042
5043                         err = maybe_insert_hole(root, inode, cur_offset,
5044                                                 hole_size);
5045                         if (err)
5046                                 break;
5047                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
5048                                                 cur_offset + hole_size - 1, 0);
5049                         hole_em = alloc_extent_map();
5050                         if (!hole_em) {
5051                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
5052                                         &BTRFS_I(inode)->runtime_flags);
5053                                 goto next;
5054                         }
5055                         hole_em->start = cur_offset;
5056                         hole_em->len = hole_size;
5057                         hole_em->orig_start = cur_offset;
5058
5059                         hole_em->block_start = EXTENT_MAP_HOLE;
5060                         hole_em->block_len = 0;
5061                         hole_em->orig_block_len = 0;
5062                         hole_em->ram_bytes = hole_size;
5063                         hole_em->bdev = fs_info->fs_devices->latest_bdev;
5064                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
5065                         hole_em->generation = fs_info->generation;
5066
5067                         while (1) {
5068                                 write_lock(&em_tree->lock);
5069                                 err = add_extent_mapping(em_tree, hole_em, 1);
5070                                 write_unlock(&em_tree->lock);
5071                                 if (err != -EEXIST)
5072                                         break;
5073                                 btrfs_drop_extent_cache(BTRFS_I(inode),
5074                                                         cur_offset,
5075                                                         cur_offset +
5076                                                         hole_size - 1, 0);
5077                         }
5078                         free_extent_map(hole_em);
5079                 }
5080 next:
5081                 free_extent_map(em);
5082                 em = NULL;
5083                 cur_offset = last_byte;
5084                 if (cur_offset >= block_end)
5085                         break;
5086         }
5087         free_extent_map(em);
5088         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state);
5089         return err;
5090 }
5091
5092 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
5093 {
5094         struct btrfs_root *root = BTRFS_I(inode)->root;
5095         struct btrfs_trans_handle *trans;
5096         loff_t oldsize = i_size_read(inode);
5097         loff_t newsize = attr->ia_size;
5098         int mask = attr->ia_valid;
5099         int ret;
5100
5101         /*
5102          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
5103          * special case where we need to update the times despite not having
5104          * these flags set.  For all other operations the VFS set these flags
5105          * explicitly if it wants a timestamp update.
5106          */
5107         if (newsize != oldsize) {
5108                 inode_inc_iversion(inode);
5109                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
5110                         inode->i_ctime = inode->i_mtime =
5111                                 current_time(inode);
5112         }
5113
5114         if (newsize > oldsize) {
5115                 /*
5116                  * Don't do an expanding truncate while snapshotting is ongoing.
5117                  * This is to ensure the snapshot captures a fully consistent
5118                  * state of this file - if the snapshot captures this expanding
5119                  * truncation, it must capture all writes that happened before
5120                  * this truncation.
5121                  */
5122                 btrfs_wait_for_snapshot_creation(root);
5123                 ret = btrfs_cont_expand(inode, oldsize, newsize);
5124                 if (ret) {
5125                         btrfs_end_write_no_snapshotting(root);
5126                         return ret;
5127                 }
5128
5129                 trans = btrfs_start_transaction(root, 1);
5130                 if (IS_ERR(trans)) {
5131                         btrfs_end_write_no_snapshotting(root);
5132                         return PTR_ERR(trans);
5133                 }
5134
5135                 i_size_write(inode, newsize);
5136                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
5137                 pagecache_isize_extended(inode, oldsize, newsize);
5138                 ret = btrfs_update_inode(trans, root, inode);
5139                 btrfs_end_write_no_snapshotting(root);
5140                 btrfs_end_transaction(trans);
5141         } else {
5142
5143                 /*
5144                  * We're truncating a file that used to have good data down to
5145                  * zero. Make sure it gets into the ordered flush list so that
5146                  * any new writes get down to disk quickly.
5147                  */
5148                 if (newsize == 0)
5149                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
5150                                 &BTRFS_I(inode)->runtime_flags);
5151
5152                 truncate_setsize(inode, newsize);
5153
5154                 /* Disable nonlocked read DIO to avoid the end less truncate */
5155                 btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
5156                 inode_dio_wait(inode);
5157                 btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
5158
5159                 ret = btrfs_truncate(inode, newsize == oldsize);
5160                 if (ret && inode->i_nlink) {
5161                         int err;
5162
5163                         /*
5164                          * Truncate failed, so fix up the in-memory size. We
5165                          * adjusted disk_i_size down as we removed extents, so
5166                          * wait for disk_i_size to be stable and then update the
5167                          * in-memory size to match.
5168                          */
5169                         err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
5170                         if (err)
5171                                 return err;
5172                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5173                 }
5174         }
5175
5176         return ret;
5177 }
5178
5179 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5180 {
5181         struct inode *inode = d_inode(dentry);
5182         struct btrfs_root *root = BTRFS_I(inode)->root;
5183         int err;
5184
5185         if (btrfs_root_readonly(root))
5186                 return -EROFS;
5187
5188         err = setattr_prepare(dentry, attr);
5189         if (err)
5190                 return err;
5191
5192         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5193                 err = btrfs_setsize(inode, attr);
5194                 if (err)
5195                         return err;
5196         }
5197
5198         if (attr->ia_valid) {
5199                 setattr_copy(inode, attr);
5200                 inode_inc_iversion(inode);
5201                 err = btrfs_dirty_inode(inode);
5202
5203                 if (!err && attr->ia_valid & ATTR_MODE)
5204                         err = posix_acl_chmod(inode, inode->i_mode);
5205         }
5206
5207         return err;
5208 }
5209
5210 /*
5211  * While truncating the inode pages during eviction, we get the VFS calling
5212  * btrfs_invalidatepage() against each page of the inode. This is slow because
5213  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5214  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5215  * extent_state structures over and over, wasting lots of time.
5216  *
5217  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5218  * those expensive operations on a per page basis and do only the ordered io
5219  * finishing, while we release here the extent_map and extent_state structures,
5220  * without the excessive merging and splitting.
5221  */
5222 static void evict_inode_truncate_pages(struct inode *inode)
5223 {
5224         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5225         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5226         struct rb_node *node;
5227
5228         ASSERT(inode->i_state & I_FREEING);
5229         truncate_inode_pages_final(&inode->i_data);
5230
5231         write_lock(&map_tree->lock);
5232         while (!RB_EMPTY_ROOT(&map_tree->map.rb_root)) {
5233                 struct extent_map *em;
5234
5235                 node = rb_first_cached(&map_tree->map);
5236                 em = rb_entry(node, struct extent_map, rb_node);
5237                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5238                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5239                 remove_extent_mapping(map_tree, em);
5240                 free_extent_map(em);
5241                 if (need_resched()) {
5242                         write_unlock(&map_tree->lock);
5243                         cond_resched();
5244                         write_lock(&map_tree->lock);
5245                 }
5246         }
5247         write_unlock(&map_tree->lock);
5248
5249         /*
5250          * Keep looping until we have no more ranges in the io tree.
5251          * We can have ongoing bios started by readpages (called from readahead)
5252          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5253          * still in progress (unlocked the pages in the bio but did not yet
5254          * unlocked the ranges in the io tree). Therefore this means some
5255          * ranges can still be locked and eviction started because before
5256          * submitting those bios, which are executed by a separate task (work
5257          * queue kthread), inode references (inode->i_count) were not taken
5258          * (which would be dropped in the end io callback of each bio).
5259          * Therefore here we effectively end up waiting for those bios and
5260          * anyone else holding locked ranges without having bumped the inode's
5261          * reference count - if we don't do it, when they access the inode's
5262          * io_tree to unlock a range it may be too late, leading to an
5263          * use-after-free issue.
5264          */
5265         spin_lock(&io_tree->lock);
5266         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5267                 struct extent_state *state;
5268                 struct extent_state *cached_state = NULL;
5269                 u64 start;
5270                 u64 end;
5271                 unsigned state_flags;
5272
5273                 node = rb_first(&io_tree->state);
5274                 state = rb_entry(node, struct extent_state, rb_node);
5275                 start = state->start;
5276                 end = state->end;
5277                 state_flags = state->state;
5278                 spin_unlock(&io_tree->lock);
5279
5280                 lock_extent_bits(io_tree, start, end, &cached_state);
5281
5282                 /*
5283                  * If still has DELALLOC flag, the extent didn't reach disk,
5284                  * and its reserved space won't be freed by delayed_ref.
5285                  * So we need to free its reserved space here.
5286                  * (Refer to comment in btrfs_invalidatepage, case 2)
5287                  *
5288                  * Note, end is the bytenr of last byte, so we need + 1 here.
5289                  */
5290                 if (state_flags & EXTENT_DELALLOC)
5291                         btrfs_qgroup_free_data(inode, NULL, start, end - start + 1);
5292
5293                 clear_extent_bit(io_tree, start, end,
5294                                  EXTENT_LOCKED | EXTENT_DIRTY |
5295                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5296                                  EXTENT_DEFRAG, 1, 1, &cached_state);
5297
5298                 cond_resched();
5299                 spin_lock(&io_tree->lock);
5300         }
5301         spin_unlock(&io_tree->lock);
5302 }
5303
5304 static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
5305                                                         struct btrfs_block_rsv *rsv)
5306 {
5307         struct btrfs_fs_info *fs_info = root->fs_info;
5308         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5309         int failures = 0;
5310
5311         for (;;) {
5312                 struct btrfs_trans_handle *trans;
5313                 int ret;
5314
5315                 ret = btrfs_block_rsv_refill(root, rsv, rsv->size,
5316                                              BTRFS_RESERVE_FLUSH_LIMIT);
5317
5318                 if (ret && ++failures > 2) {
5319                         btrfs_warn(fs_info,
5320                                    "could not allocate space for a delete; will truncate on mount");
5321                         return ERR_PTR(-ENOSPC);
5322                 }
5323
5324                 trans = btrfs_join_transaction(root);
5325                 if (IS_ERR(trans) || !ret)
5326                         return trans;
5327
5328                 /*
5329                  * Try to steal from the global reserve if there is space for
5330                  * it.
5331                  */
5332                 if (!btrfs_check_space_for_delayed_refs(trans) &&
5333                     !btrfs_block_rsv_migrate(global_rsv, rsv, rsv->size, false))
5334                         return trans;
5335
5336                 /* If not, commit and try again. */
5337                 ret = btrfs_commit_transaction(trans);
5338                 if (ret)
5339                         return ERR_PTR(ret);
5340         }
5341 }
5342
5343 void btrfs_evict_inode(struct inode *inode)
5344 {
5345         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5346         struct btrfs_trans_handle *trans;
5347         struct btrfs_root *root = BTRFS_I(inode)->root;
5348         struct btrfs_block_rsv *rsv;
5349         int ret;
5350
5351         trace_btrfs_inode_evict(inode);
5352
5353         if (!root) {
5354                 clear_inode(inode);
5355                 return;
5356         }
5357
5358         evict_inode_truncate_pages(inode);
5359
5360         if (inode->i_nlink &&
5361             ((btrfs_root_refs(&root->root_item) != 0 &&
5362               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5363              btrfs_is_free_space_inode(BTRFS_I(inode))))
5364                 goto no_delete;
5365
5366         if (is_bad_inode(inode))
5367                 goto no_delete;
5368
5369         btrfs_free_io_failure_record(BTRFS_I(inode), 0, (u64)-1);
5370
5371         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
5372                 goto no_delete;
5373
5374         if (inode->i_nlink > 0) {
5375                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5376                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5377                 goto no_delete;
5378         }
5379
5380         ret = btrfs_commit_inode_delayed_inode(BTRFS_I(inode));
5381         if (ret)
5382                 goto no_delete;
5383
5384         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
5385         if (!rsv)
5386                 goto no_delete;
5387         rsv->size = btrfs_calc_trunc_metadata_size(fs_info, 1);
5388         rsv->failfast = 1;
5389
5390         btrfs_i_size_write(BTRFS_I(inode), 0);
5391
5392         while (1) {
5393                 trans = evict_refill_and_join(root, rsv);
5394                 if (IS_ERR(trans))
5395                         goto free_rsv;
5396
5397                 trans->block_rsv = rsv;
5398
5399                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5400                 trans->block_rsv = &fs_info->trans_block_rsv;
5401                 btrfs_end_transaction(trans);
5402                 btrfs_btree_balance_dirty(fs_info);
5403                 if (ret && ret != -ENOSPC && ret != -EAGAIN)
5404                         goto free_rsv;
5405                 else if (!ret)
5406                         break;
5407         }
5408
5409         /*
5410          * Errors here aren't a big deal, it just means we leave orphan items in
5411          * the tree. They will be cleaned up on the next mount. If the inode
5412          * number gets reused, cleanup deletes the orphan item without doing
5413          * anything, and unlink reuses the existing orphan item.
5414          *
5415          * If it turns out that we are dropping too many of these, we might want
5416          * to add a mechanism for retrying these after a commit.
5417          */
5418         trans = evict_refill_and_join(root, rsv);
5419         if (!IS_ERR(trans)) {
5420                 trans->block_rsv = rsv;
5421                 btrfs_orphan_del(trans, BTRFS_I(inode));
5422                 trans->block_rsv = &fs_info->trans_block_rsv;
5423                 btrfs_end_transaction(trans);
5424         }
5425
5426         if (!(root == fs_info->tree_root ||
5427               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5428                 btrfs_return_ino(root, btrfs_ino(BTRFS_I(inode)));
5429
5430 free_rsv:
5431         btrfs_free_block_rsv(fs_info, rsv);
5432 no_delete:
5433         /*
5434          * If we didn't successfully delete, the orphan item will still be in
5435          * the tree and we'll retry on the next mount. Again, we might also want
5436          * to retry these periodically in the future.
5437          */
5438         btrfs_remove_delayed_node(BTRFS_I(inode));
5439         clear_inode(inode);
5440 }
5441
5442 /*
5443  * this returns the key found in the dir entry in the location pointer.
5444  * If no dir entries were found, returns -ENOENT.
5445  * If found a corrupted location in dir entry, returns -EUCLEAN.
5446  */
5447 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5448                                struct btrfs_key *location)
5449 {
5450         const char *name = dentry->d_name.name;
5451         int namelen = dentry->d_name.len;
5452         struct btrfs_dir_item *di;
5453         struct btrfs_path *path;
5454         struct btrfs_root *root = BTRFS_I(dir)->root;
5455         int ret = 0;
5456
5457         path = btrfs_alloc_path();
5458         if (!path)
5459                 return -ENOMEM;
5460
5461         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
5462                         name, namelen, 0);
5463         if (IS_ERR_OR_NULL(di)) {
5464                 ret = di ? PTR_ERR(di) : -ENOENT;
5465                 goto out;
5466         }
5467
5468         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5469         if (location->type != BTRFS_INODE_ITEM_KEY &&
5470             location->type != BTRFS_ROOT_ITEM_KEY) {
5471                 ret = -EUCLEAN;
5472                 btrfs_warn(root->fs_info,
5473 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
5474                            __func__, name, btrfs_ino(BTRFS_I(dir)),
5475                            location->objectid, location->type, location->offset);
5476         }
5477 out:
5478         btrfs_free_path(path);
5479         return ret;
5480 }
5481
5482 /*
5483  * when we hit a tree root in a directory, the btrfs part of the inode
5484  * needs to be changed to reflect the root directory of the tree root.  This
5485  * is kind of like crossing a mount point.
5486  */
5487 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
5488                                     struct inode *dir,
5489                                     struct dentry *dentry,
5490                                     struct btrfs_key *location,
5491                                     struct btrfs_root **sub_root)
5492 {
5493         struct btrfs_path *path;
5494         struct btrfs_root *new_root;
5495         struct btrfs_root_ref *ref;
5496         struct extent_buffer *leaf;
5497         struct btrfs_key key;
5498         int ret;
5499         int err = 0;
5500
5501         path = btrfs_alloc_path();
5502         if (!path) {
5503                 err = -ENOMEM;
5504                 goto out;
5505         }
5506
5507         err = -ENOENT;
5508         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5509         key.type = BTRFS_ROOT_REF_KEY;
5510         key.offset = location->objectid;
5511
5512         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5513         if (ret) {
5514                 if (ret < 0)
5515                         err = ret;
5516                 goto out;
5517         }
5518
5519         leaf = path->nodes[0];
5520         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5521         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
5522             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5523                 goto out;
5524
5525         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5526                                    (unsigned long)(ref + 1),
5527                                    dentry->d_name.len);
5528         if (ret)
5529                 goto out;
5530
5531         btrfs_release_path(path);
5532
5533         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5534         if (IS_ERR(new_root)) {
5535                 err = PTR_ERR(new_root);
5536                 goto out;
5537         }
5538
5539         *sub_root = new_root;
5540         location->objectid = btrfs_root_dirid(&new_root->root_item);
5541         location->type = BTRFS_INODE_ITEM_KEY;
5542         location->offset = 0;
5543         err = 0;
5544 out:
5545         btrfs_free_path(path);
5546         return err;
5547 }
5548
5549 static void inode_tree_add(struct inode *inode)
5550 {
5551         struct btrfs_root *root = BTRFS_I(inode)->root;
5552         struct btrfs_inode *entry;
5553         struct rb_node **p;
5554         struct rb_node *parent;
5555         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5556         u64 ino = btrfs_ino(BTRFS_I(inode));
5557
5558         if (inode_unhashed(inode))
5559                 return;
5560         parent = NULL;
5561         spin_lock(&root->inode_lock);
5562         p = &root->inode_tree.rb_node;
5563         while (*p) {
5564                 parent = *p;
5565                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5566
5567                 if (ino < btrfs_ino(entry))
5568                         p = &parent->rb_left;
5569                 else if (ino > btrfs_ino(entry))
5570                         p = &parent->rb_right;
5571                 else {
5572                         WARN_ON(!(entry->vfs_inode.i_state &
5573                                   (I_WILL_FREE | I_FREEING)));
5574                         rb_replace_node(parent, new, &root->inode_tree);
5575                         RB_CLEAR_NODE(parent);
5576                         spin_unlock(&root->inode_lock);
5577                         return;
5578                 }
5579         }
5580         rb_link_node(new, parent, p);
5581         rb_insert_color(new, &root->inode_tree);
5582         spin_unlock(&root->inode_lock);
5583 }
5584
5585 static void inode_tree_del(struct inode *inode)
5586 {
5587         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5588         struct btrfs_root *root = BTRFS_I(inode)->root;
5589         int empty = 0;
5590
5591         spin_lock(&root->inode_lock);
5592         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5593                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5594                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5595                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5596         }
5597         spin_unlock(&root->inode_lock);
5598
5599         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5600                 synchronize_srcu(&fs_info->subvol_srcu);
5601                 spin_lock(&root->inode_lock);
5602                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5603                 spin_unlock(&root->inode_lock);
5604                 if (empty)
5605                         btrfs_add_dead_root(root);
5606         }
5607 }
5608
5609
5610 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5611 {
5612         struct btrfs_iget_args *args = p;
5613         inode->i_ino = args->location->objectid;
5614         memcpy(&BTRFS_I(inode)->location, args->location,
5615                sizeof(*args->location));
5616         BTRFS_I(inode)->root = args->root;
5617         return 0;
5618 }
5619
5620 static int btrfs_find_actor(struct inode *inode, void *opaque)
5621 {
5622         struct btrfs_iget_args *args = opaque;
5623         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5624                 args->root == BTRFS_I(inode)->root;
5625 }
5626
5627 static struct inode *btrfs_iget_locked(struct super_block *s,
5628                                        struct btrfs_key *location,
5629                                        struct btrfs_root *root)
5630 {
5631         struct inode *inode;
5632         struct btrfs_iget_args args;
5633         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5634
5635         args.location = location;
5636         args.root = root;
5637
5638         inode = iget5_locked(s, hashval, btrfs_find_actor,
5639                              btrfs_init_locked_inode,
5640                              (void *)&args);
5641         return inode;
5642 }
5643
5644 /* Get an inode object given its location and corresponding root.
5645  * Returns in *is_new if the inode was read from disk
5646  */
5647 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5648                          struct btrfs_root *root, int *new)
5649 {
5650         struct inode *inode;
5651
5652         inode = btrfs_iget_locked(s, location, root);
5653         if (!inode)
5654                 return ERR_PTR(-ENOMEM);
5655
5656         if (inode->i_state & I_NEW) {
5657                 int ret;
5658
5659                 ret = btrfs_read_locked_inode(inode);
5660                 if (!ret) {
5661                         inode_tree_add(inode);
5662                         unlock_new_inode(inode);
5663                         if (new)
5664                                 *new = 1;
5665                 } else {
5666                         iget_failed(inode);
5667                         /*
5668                          * ret > 0 can come from btrfs_search_slot called by
5669                          * btrfs_read_locked_inode, this means the inode item
5670                          * was not found.
5671                          */
5672                         if (ret > 0)
5673                                 ret = -ENOENT;
5674                         inode = ERR_PTR(ret);
5675                 }
5676         }
5677
5678         return inode;
5679 }
5680
5681 static struct inode *new_simple_dir(struct super_block *s,
5682                                     struct btrfs_key *key,
5683                                     struct btrfs_root *root)
5684 {
5685         struct inode *inode = new_inode(s);
5686
5687         if (!inode)
5688                 return ERR_PTR(-ENOMEM);
5689
5690         BTRFS_I(inode)->root = root;
5691         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5692         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5693
5694         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5695         inode->i_op = &btrfs_dir_ro_inode_operations;
5696         inode->i_opflags &= ~IOP_XATTR;
5697         inode->i_fop = &simple_dir_operations;
5698         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5699         inode->i_mtime = current_time(inode);
5700         inode->i_atime = inode->i_mtime;
5701         inode->i_ctime = inode->i_mtime;
5702         BTRFS_I(inode)->i_otime = inode->i_mtime;
5703
5704         return inode;
5705 }
5706
5707 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5708 {
5709         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5710         struct inode *inode;
5711         struct btrfs_root *root = BTRFS_I(dir)->root;
5712         struct btrfs_root *sub_root = root;
5713         struct btrfs_key location;
5714         int index;
5715         int ret = 0;
5716
5717         if (dentry->d_name.len > BTRFS_NAME_LEN)
5718                 return ERR_PTR(-ENAMETOOLONG);
5719
5720         ret = btrfs_inode_by_name(dir, dentry, &location);
5721         if (ret < 0)
5722                 return ERR_PTR(ret);
5723
5724         if (location.type == BTRFS_INODE_ITEM_KEY) {
5725                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5726                 return inode;
5727         }
5728
5729         index = srcu_read_lock(&fs_info->subvol_srcu);
5730         ret = fixup_tree_root_location(fs_info, dir, dentry,
5731                                        &location, &sub_root);
5732         if (ret < 0) {
5733                 if (ret != -ENOENT)
5734                         inode = ERR_PTR(ret);
5735                 else
5736                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5737         } else {
5738                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5739         }
5740         srcu_read_unlock(&fs_info->subvol_srcu, index);
5741
5742         if (!IS_ERR(inode) && root != sub_root) {
5743                 down_read(&fs_info->cleanup_work_sem);
5744                 if (!sb_rdonly(inode->i_sb))
5745                         ret = btrfs_orphan_cleanup(sub_root);
5746                 up_read(&fs_info->cleanup_work_sem);
5747                 if (ret) {
5748                         iput(inode);
5749                         inode = ERR_PTR(ret);
5750                 }
5751         }
5752
5753         return inode;
5754 }
5755
5756 static int btrfs_dentry_delete(const struct dentry *dentry)
5757 {
5758         struct btrfs_root *root;
5759         struct inode *inode = d_inode(dentry);
5760
5761         if (!inode && !IS_ROOT(dentry))
5762                 inode = d_inode(dentry->d_parent);
5763
5764         if (inode) {
5765                 root = BTRFS_I(inode)->root;
5766                 if (btrfs_root_refs(&root->root_item) == 0)
5767                         return 1;
5768
5769                 if (btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5770                         return 1;
5771         }
5772         return 0;
5773 }
5774
5775 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5776                                    unsigned int flags)
5777 {
5778         struct inode *inode = btrfs_lookup_dentry(dir, dentry);
5779
5780         if (inode == ERR_PTR(-ENOENT))
5781                 inode = NULL;
5782         return d_splice_alias(inode, dentry);
5783 }
5784
5785 unsigned char btrfs_filetype_table[] = {
5786         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5787 };
5788
5789 /*
5790  * All this infrastructure exists because dir_emit can fault, and we are holding
5791  * the tree lock when doing readdir.  For now just allocate a buffer and copy
5792  * our information into that, and then dir_emit from the buffer.  This is
5793  * similar to what NFS does, only we don't keep the buffer around in pagecache
5794  * because I'm afraid I'll mess that up.  Long term we need to make filldir do
5795  * copy_to_user_inatomic so we don't have to worry about page faulting under the
5796  * tree lock.
5797  */
5798 static int btrfs_opendir(struct inode *inode, struct file *file)
5799 {
5800         struct btrfs_file_private *private;
5801
5802         private = kzalloc(sizeof(struct btrfs_file_private), GFP_KERNEL);
5803         if (!private)
5804                 return -ENOMEM;
5805         private->filldir_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
5806         if (!private->filldir_buf) {
5807                 kfree(private);
5808                 return -ENOMEM;
5809         }
5810         file->private_data = private;
5811         return 0;
5812 }
5813
5814 struct dir_entry {
5815         u64 ino;
5816         u64 offset;
5817         unsigned type;
5818         int name_len;
5819 };
5820
5821 static int btrfs_filldir(void *addr, int entries, struct dir_context *ctx)
5822 {
5823         while (entries--) {
5824                 struct dir_entry *entry = addr;
5825                 char *name = (char *)(entry + 1);
5826
5827                 ctx->pos = get_unaligned(&entry->offset);
5828                 if (!dir_emit(ctx, name, get_unaligned(&entry->name_len),
5829                                          get_unaligned(&entry->ino),
5830                                          get_unaligned(&entry->type)))
5831                         return 1;
5832                 addr += sizeof(struct dir_entry) +
5833                         get_unaligned(&entry->name_len);
5834                 ctx->pos++;
5835         }
5836         return 0;
5837 }
5838
5839 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5840 {
5841         struct inode *inode = file_inode(file);
5842         struct btrfs_root *root = BTRFS_I(inode)->root;
5843         struct btrfs_file_private *private = file->private_data;
5844         struct btrfs_dir_item *di;
5845         struct btrfs_key key;
5846         struct btrfs_key found_key;
5847         struct btrfs_path *path;
5848         void *addr;
5849         struct list_head ins_list;
5850         struct list_head del_list;
5851         int ret;
5852         struct extent_buffer *leaf;
5853         int slot;
5854         char *name_ptr;
5855         int name_len;
5856         int entries = 0;
5857         int total_len = 0;
5858         bool put = false;
5859         struct btrfs_key location;
5860
5861         if (!dir_emit_dots(file, ctx))
5862                 return 0;
5863
5864         path = btrfs_alloc_path();
5865         if (!path)
5866                 return -ENOMEM;
5867
5868         addr = private->filldir_buf;
5869         path->reada = READA_FORWARD;
5870
5871         INIT_LIST_HEAD(&ins_list);
5872         INIT_LIST_HEAD(&del_list);
5873         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5874
5875 again:
5876         key.type = BTRFS_DIR_INDEX_KEY;
5877         key.offset = ctx->pos;
5878         key.objectid = btrfs_ino(BTRFS_I(inode));
5879
5880         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5881         if (ret < 0)
5882                 goto err;
5883
5884         while (1) {
5885                 struct dir_entry *entry;
5886
5887                 leaf = path->nodes[0];
5888                 slot = path->slots[0];
5889                 if (slot >= btrfs_header_nritems(leaf)) {
5890                         ret = btrfs_next_leaf(root, path);
5891                         if (ret < 0)
5892                                 goto err;
5893                         else if (ret > 0)
5894                                 break;
5895                         continue;
5896                 }
5897
5898                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5899
5900                 if (found_key.objectid != key.objectid)
5901                         break;
5902                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5903                         break;
5904                 if (found_key.offset < ctx->pos)
5905                         goto next;
5906                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5907                         goto next;
5908                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5909                 name_len = btrfs_dir_name_len(leaf, di);
5910                 if ((total_len + sizeof(struct dir_entry) + name_len) >=
5911                     PAGE_SIZE) {
5912                         btrfs_release_path(path);
5913                         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5914                         if (ret)
5915                                 goto nopos;
5916                         addr = private->filldir_buf;
5917                         entries = 0;
5918                         total_len = 0;
5919                         goto again;
5920                 }
5921
5922                 entry = addr;
5923                 put_unaligned(name_len, &entry->name_len);
5924                 name_ptr = (char *)(entry + 1);
5925                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5926                                    name_len);
5927                 put_unaligned(btrfs_filetype_table[btrfs_dir_type(leaf, di)],
5928                                 &entry->type);
5929                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5930                 put_unaligned(location.objectid, &entry->ino);
5931                 put_unaligned(found_key.offset, &entry->offset);
5932                 entries++;
5933                 addr += sizeof(struct dir_entry) + name_len;
5934                 total_len += sizeof(struct dir_entry) + name_len;
5935 next:
5936                 path->slots[0]++;
5937         }
5938         btrfs_release_path(path);
5939
5940         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5941         if (ret)
5942                 goto nopos;
5943
5944         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5945         if (ret)
5946                 goto nopos;
5947
5948         /*
5949          * Stop new entries from being returned after we return the last
5950          * entry.
5951          *
5952          * New directory entries are assigned a strictly increasing
5953          * offset.  This means that new entries created during readdir
5954          * are *guaranteed* to be seen in the future by that readdir.
5955          * This has broken buggy programs which operate on names as
5956          * they're returned by readdir.  Until we re-use freed offsets
5957          * we have this hack to stop new entries from being returned
5958          * under the assumption that they'll never reach this huge
5959          * offset.
5960          *
5961          * This is being careful not to overflow 32bit loff_t unless the
5962          * last entry requires it because doing so has broken 32bit apps
5963          * in the past.
5964          */
5965         if (ctx->pos >= INT_MAX)
5966                 ctx->pos = LLONG_MAX;
5967         else
5968                 ctx->pos = INT_MAX;
5969 nopos:
5970         ret = 0;
5971 err:
5972         if (put)
5973                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5974         btrfs_free_path(path);
5975         return ret;
5976 }
5977
5978 /*
5979  * This is somewhat expensive, updating the tree every time the
5980  * inode changes.  But, it is most likely to find the inode in cache.
5981  * FIXME, needs more benchmarking...there are no reasons other than performance
5982  * to keep or drop this code.
5983  */
5984 static int btrfs_dirty_inode(struct inode *inode)
5985 {
5986         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5987         struct btrfs_root *root = BTRFS_I(inode)->root;
5988         struct btrfs_trans_handle *trans;
5989         int ret;
5990
5991         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5992                 return 0;
5993
5994         trans = btrfs_join_transaction(root);
5995         if (IS_ERR(trans))
5996                 return PTR_ERR(trans);
5997
5998         ret = btrfs_update_inode(trans, root, inode);
5999         if (ret && ret == -ENOSPC) {
6000                 /* whoops, lets try again with the full transaction */
6001                 btrfs_end_transaction(trans);
6002                 trans = btrfs_start_transaction(root, 1);
6003                 if (IS_ERR(trans))
6004                         return PTR_ERR(trans);
6005
6006                 ret = btrfs_update_inode(trans, root, inode);
6007         }
6008         btrfs_end_transaction(trans);
6009         if (BTRFS_I(inode)->delayed_node)
6010                 btrfs_balance_delayed_items(fs_info);
6011
6012         return ret;
6013 }
6014
6015 /*
6016  * This is a copy of file_update_time.  We need this so we can return error on
6017  * ENOSPC for updating the inode in the case of file write and mmap writes.
6018  */
6019 static int btrfs_update_time(struct inode *inode, struct timespec64 *now,
6020                              int flags)
6021 {
6022         struct btrfs_root *root = BTRFS_I(inode)->root;
6023         bool dirty = flags & ~S_VERSION;
6024
6025         if (btrfs_root_readonly(root))
6026                 return -EROFS;
6027
6028         if (flags & S_VERSION)
6029                 dirty |= inode_maybe_inc_iversion(inode, dirty);
6030         if (flags & S_CTIME)
6031                 inode->i_ctime = *now;
6032         if (flags & S_MTIME)
6033                 inode->i_mtime = *now;
6034         if (flags & S_ATIME)
6035                 inode->i_atime = *now;
6036         return dirty ? btrfs_dirty_inode(inode) : 0;
6037 }
6038
6039 /*
6040  * find the highest existing sequence number in a directory
6041  * and then set the in-memory index_cnt variable to reflect
6042  * free sequence numbers
6043  */
6044 static int btrfs_set_inode_index_count(struct btrfs_inode *inode)
6045 {
6046         struct btrfs_root *root = inode->root;
6047         struct btrfs_key key, found_key;
6048         struct btrfs_path *path;
6049         struct extent_buffer *leaf;
6050         int ret;
6051
6052         key.objectid = btrfs_ino(inode);
6053         key.type = BTRFS_DIR_INDEX_KEY;
6054         key.offset = (u64)-1;
6055
6056         path = btrfs_alloc_path();
6057         if (!path)
6058                 return -ENOMEM;
6059
6060         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6061         if (ret < 0)
6062                 goto out;
6063         /* FIXME: we should be able to handle this */
6064         if (ret == 0)
6065                 goto out;
6066         ret = 0;
6067
6068         /*
6069          * MAGIC NUMBER EXPLANATION:
6070          * since we search a directory based on f_pos we have to start at 2
6071          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6072          * else has to start at 2
6073          */
6074         if (path->slots[0] == 0) {
6075                 inode->index_cnt = 2;
6076                 goto out;
6077         }
6078
6079         path->slots[0]--;
6080
6081         leaf = path->nodes[0];
6082         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6083
6084         if (found_key.objectid != btrfs_ino(inode) ||
6085             found_key.type != BTRFS_DIR_INDEX_KEY) {
6086                 inode->index_cnt = 2;
6087                 goto out;
6088         }
6089
6090         inode->index_cnt = found_key.offset + 1;
6091 out:
6092         btrfs_free_path(path);
6093         return ret;
6094 }
6095
6096 /*
6097  * helper to find a free sequence number in a given directory.  This current
6098  * code is very simple, later versions will do smarter things in the btree
6099  */
6100 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index)
6101 {
6102         int ret = 0;
6103
6104         if (dir->index_cnt == (u64)-1) {
6105                 ret = btrfs_inode_delayed_dir_index_count(dir);
6106                 if (ret) {
6107                         ret = btrfs_set_inode_index_count(dir);
6108                         if (ret)
6109                                 return ret;
6110                 }
6111         }
6112
6113         *index = dir->index_cnt;
6114         dir->index_cnt++;
6115
6116         return ret;
6117 }
6118
6119 static int btrfs_insert_inode_locked(struct inode *inode)
6120 {
6121         struct btrfs_iget_args args;
6122         args.location = &BTRFS_I(inode)->location;
6123         args.root = BTRFS_I(inode)->root;
6124
6125         return insert_inode_locked4(inode,
6126                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6127                    btrfs_find_actor, &args);
6128 }
6129
6130 /*
6131  * Inherit flags from the parent inode.
6132  *
6133  * Currently only the compression flags and the cow flags are inherited.
6134  */
6135 static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
6136 {
6137         unsigned int flags;
6138
6139         if (!dir)
6140                 return;
6141
6142         flags = BTRFS_I(dir)->flags;
6143
6144         if (flags & BTRFS_INODE_NOCOMPRESS) {
6145                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
6146                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
6147         } else if (flags & BTRFS_INODE_COMPRESS) {
6148                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
6149                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
6150         }
6151
6152         if (flags & BTRFS_INODE_NODATACOW) {
6153                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
6154                 if (S_ISREG(inode->i_mode))
6155                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6156         }
6157
6158         btrfs_sync_inode_flags_to_i_flags(inode);
6159 }
6160
6161 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6162                                      struct btrfs_root *root,
6163                                      struct inode *dir,
6164                                      const char *name, int name_len,
6165                                      u64 ref_objectid, u64 objectid,
6166                                      umode_t mode, u64 *index)
6167 {
6168         struct btrfs_fs_info *fs_info = root->fs_info;
6169         struct inode *inode;
6170         struct btrfs_inode_item *inode_item;
6171         struct btrfs_key *location;
6172         struct btrfs_path *path;
6173         struct btrfs_inode_ref *ref;
6174         struct btrfs_key key[2];
6175         u32 sizes[2];
6176         int nitems = name ? 2 : 1;
6177         unsigned long ptr;
6178         int ret;
6179
6180         path = btrfs_alloc_path();
6181         if (!path)
6182                 return ERR_PTR(-ENOMEM);
6183
6184         inode = new_inode(fs_info->sb);
6185         if (!inode) {
6186                 btrfs_free_path(path);
6187                 return ERR_PTR(-ENOMEM);
6188         }
6189
6190         /*
6191          * O_TMPFILE, set link count to 0, so that after this point,
6192          * we fill in an inode item with the correct link count.
6193          */
6194         if (!name)
6195                 set_nlink(inode, 0);
6196
6197         /*
6198          * we have to initialize this early, so we can reclaim the inode
6199          * number if we fail afterwards in this function.
6200          */
6201         inode->i_ino = objectid;
6202
6203         if (dir && name) {
6204                 trace_btrfs_inode_request(dir);
6205
6206                 ret = btrfs_set_inode_index(BTRFS_I(dir), index);
6207                 if (ret) {
6208                         btrfs_free_path(path);
6209                         iput(inode);
6210                         return ERR_PTR(ret);
6211                 }
6212         } else if (dir) {
6213                 *index = 0;
6214         }
6215         /*
6216          * index_cnt is ignored for everything but a dir,
6217          * btrfs_set_inode_index_count has an explanation for the magic
6218          * number
6219          */
6220         BTRFS_I(inode)->index_cnt = 2;
6221         BTRFS_I(inode)->dir_index = *index;
6222         BTRFS_I(inode)->root = root;
6223         BTRFS_I(inode)->generation = trans->transid;
6224         inode->i_generation = BTRFS_I(inode)->generation;
6225
6226         /*
6227          * We could have gotten an inode number from somebody who was fsynced
6228          * and then removed in this same transaction, so let's just set full
6229          * sync since it will be a full sync anyway and this will blow away the
6230          * old info in the log.
6231          */
6232         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6233
6234         key[0].objectid = objectid;
6235         key[0].type = BTRFS_INODE_ITEM_KEY;
6236         key[0].offset = 0;
6237
6238         sizes[0] = sizeof(struct btrfs_inode_item);
6239
6240         if (name) {
6241                 /*
6242                  * Start new inodes with an inode_ref. This is slightly more
6243                  * efficient for small numbers of hard links since they will
6244                  * be packed into one item. Extended refs will kick in if we
6245                  * add more hard links than can fit in the ref item.
6246                  */
6247                 key[1].objectid = objectid;
6248                 key[1].type = BTRFS_INODE_REF_KEY;
6249                 key[1].offset = ref_objectid;
6250
6251                 sizes[1] = name_len + sizeof(*ref);
6252         }
6253
6254         location = &BTRFS_I(inode)->location;
6255         location->objectid = objectid;
6256         location->offset = 0;
6257         location->type = BTRFS_INODE_ITEM_KEY;
6258
6259         ret = btrfs_insert_inode_locked(inode);
6260         if (ret < 0) {
6261                 iput(inode);
6262                 goto fail;
6263         }
6264
6265         path->leave_spinning = 1;
6266         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6267         if (ret != 0)
6268                 goto fail_unlock;
6269
6270         inode_init_owner(inode, dir, mode);
6271         inode_set_bytes(inode, 0);
6272
6273         inode->i_mtime = current_time(inode);
6274         inode->i_atime = inode->i_mtime;
6275         inode->i_ctime = inode->i_mtime;
6276         BTRFS_I(inode)->i_otime = inode->i_mtime;
6277
6278         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6279                                   struct btrfs_inode_item);
6280         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
6281                              sizeof(*inode_item));
6282         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6283
6284         if (name) {
6285                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6286                                      struct btrfs_inode_ref);
6287                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6288                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6289                 ptr = (unsigned long)(ref + 1);
6290                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6291         }
6292
6293         btrfs_mark_buffer_dirty(path->nodes[0]);
6294         btrfs_free_path(path);
6295
6296         btrfs_inherit_iflags(inode, dir);
6297
6298         if (S_ISREG(mode)) {
6299                 if (btrfs_test_opt(fs_info, NODATASUM))
6300                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6301                 if (btrfs_test_opt(fs_info, NODATACOW))
6302                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6303                                 BTRFS_INODE_NODATASUM;
6304         }
6305
6306         inode_tree_add(inode);
6307
6308         trace_btrfs_inode_new(inode);
6309         btrfs_set_inode_last_trans(trans, inode);
6310
6311         btrfs_update_root_times(trans, root);
6312
6313         ret = btrfs_inode_inherit_props(trans, inode, dir);
6314         if (ret)
6315                 btrfs_err(fs_info,
6316                           "error inheriting props for ino %llu (root %llu): %d",
6317                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
6318
6319         return inode;
6320
6321 fail_unlock:
6322         discard_new_inode(inode);
6323 fail:
6324         if (dir && name)
6325                 BTRFS_I(dir)->index_cnt--;
6326         btrfs_free_path(path);
6327         return ERR_PTR(ret);
6328 }
6329
6330 static inline u8 btrfs_inode_type(struct inode *inode)
6331 {
6332         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6333 }
6334
6335 /*
6336  * utility function to add 'inode' into 'parent_inode' with
6337  * a give name and a given sequence number.
6338  * if 'add_backref' is true, also insert a backref from the
6339  * inode to the parent directory.
6340  */
6341 int btrfs_add_link(struct btrfs_trans_handle *trans,
6342                    struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
6343                    const char *name, int name_len, int add_backref, u64 index)
6344 {
6345         int ret = 0;
6346         struct btrfs_key key;
6347         struct btrfs_root *root = parent_inode->root;
6348         u64 ino = btrfs_ino(inode);
6349         u64 parent_ino = btrfs_ino(parent_inode);
6350
6351         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6352                 memcpy(&key, &inode->root->root_key, sizeof(key));
6353         } else {
6354                 key.objectid = ino;
6355                 key.type = BTRFS_INODE_ITEM_KEY;
6356                 key.offset = 0;
6357         }
6358
6359         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6360                 ret = btrfs_add_root_ref(trans, key.objectid,
6361                                          root->root_key.objectid, parent_ino,
6362                                          index, name, name_len);
6363         } else if (add_backref) {
6364                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6365                                              parent_ino, index);
6366         }
6367
6368         /* Nothing to clean up yet */
6369         if (ret)
6370                 return ret;
6371
6372         ret = btrfs_insert_dir_item(trans, name, name_len, parent_inode, &key,
6373                                     btrfs_inode_type(&inode->vfs_inode), index);
6374         if (ret == -EEXIST || ret == -EOVERFLOW)
6375                 goto fail_dir_item;
6376         else if (ret) {
6377                 btrfs_abort_transaction(trans, ret);
6378                 return ret;
6379         }
6380
6381         btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
6382                            name_len * 2);
6383         inode_inc_iversion(&parent_inode->vfs_inode);
6384         parent_inode->vfs_inode.i_mtime = parent_inode->vfs_inode.i_ctime =
6385                 current_time(&parent_inode->vfs_inode);
6386         ret = btrfs_update_inode(trans, root, &parent_inode->vfs_inode);
6387         if (ret)
6388                 btrfs_abort_transaction(trans, ret);
6389         return ret;
6390
6391 fail_dir_item:
6392         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6393                 u64 local_index;
6394                 int err;
6395                 err = btrfs_del_root_ref(trans, key.objectid,
6396                                          root->root_key.objectid, parent_ino,
6397                                          &local_index, name, name_len);
6398
6399         } else if (add_backref) {
6400                 u64 local_index;
6401                 int err;
6402
6403                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6404                                           ino, parent_ino, &local_index);
6405         }
6406         return ret;
6407 }
6408
6409 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6410                             struct btrfs_inode *dir, struct dentry *dentry,
6411                             struct btrfs_inode *inode, int backref, u64 index)
6412 {
6413         int err = btrfs_add_link(trans, dir, inode,
6414                                  dentry->d_name.name, dentry->d_name.len,
6415                                  backref, index);
6416         if (err > 0)
6417                 err = -EEXIST;
6418         return err;
6419 }
6420
6421 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6422                         umode_t mode, dev_t rdev)
6423 {
6424         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6425         struct btrfs_trans_handle *trans;
6426         struct btrfs_root *root = BTRFS_I(dir)->root;
6427         struct inode *inode = NULL;
6428         int err;
6429         u64 objectid;
6430         u64 index = 0;
6431
6432         /*
6433          * 2 for inode item and ref
6434          * 2 for dir items
6435          * 1 for xattr if selinux is on
6436          */
6437         trans = btrfs_start_transaction(root, 5);
6438         if (IS_ERR(trans))
6439                 return PTR_ERR(trans);
6440
6441         err = btrfs_find_free_ino(root, &objectid);
6442         if (err)
6443                 goto out_unlock;
6444
6445         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6446                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6447                         mode, &index);
6448         if (IS_ERR(inode)) {
6449                 err = PTR_ERR(inode);
6450                 inode = NULL;
6451                 goto out_unlock;
6452         }
6453
6454         /*
6455         * If the active LSM wants to access the inode during
6456         * d_instantiate it needs these. Smack checks to see
6457         * if the filesystem supports xattrs by looking at the
6458         * ops vector.
6459         */
6460         inode->i_op = &btrfs_special_inode_operations;
6461         init_special_inode(inode, inode->i_mode, rdev);
6462
6463         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6464         if (err)
6465                 goto out_unlock;
6466
6467         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6468                         0, index);
6469         if (err)
6470                 goto out_unlock;
6471
6472         btrfs_update_inode(trans, root, inode);
6473         d_instantiate_new(dentry, inode);
6474
6475 out_unlock:
6476         btrfs_end_transaction(trans);
6477         btrfs_btree_balance_dirty(fs_info);
6478         if (err && inode) {
6479                 inode_dec_link_count(inode);
6480                 discard_new_inode(inode);
6481         }
6482         return err;
6483 }
6484
6485 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6486                         umode_t mode, bool excl)
6487 {
6488         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6489         struct btrfs_trans_handle *trans;
6490         struct btrfs_root *root = BTRFS_I(dir)->root;
6491         struct inode *inode = NULL;
6492         int err;
6493         u64 objectid;
6494         u64 index = 0;
6495
6496         /*
6497          * 2 for inode item and ref
6498          * 2 for dir items
6499          * 1 for xattr if selinux is on
6500          */
6501         trans = btrfs_start_transaction(root, 5);
6502         if (IS_ERR(trans))
6503                 return PTR_ERR(trans);
6504
6505         err = btrfs_find_free_ino(root, &objectid);
6506         if (err)
6507                 goto out_unlock;
6508
6509         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6510                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6511                         mode, &index);
6512         if (IS_ERR(inode)) {
6513                 err = PTR_ERR(inode);
6514                 inode = NULL;
6515                 goto out_unlock;
6516         }
6517         /*
6518         * If the active LSM wants to access the inode during
6519         * d_instantiate it needs these. Smack checks to see
6520         * if the filesystem supports xattrs by looking at the
6521         * ops vector.
6522         */
6523         inode->i_fop = &btrfs_file_operations;
6524         inode->i_op = &btrfs_file_inode_operations;
6525         inode->i_mapping->a_ops = &btrfs_aops;
6526
6527         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6528         if (err)
6529                 goto out_unlock;
6530
6531         err = btrfs_update_inode(trans, root, inode);
6532         if (err)
6533                 goto out_unlock;
6534
6535         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6536                         0, index);
6537         if (err)
6538                 goto out_unlock;
6539
6540         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6541         d_instantiate_new(dentry, inode);
6542
6543 out_unlock:
6544         btrfs_end_transaction(trans);
6545         if (err && inode) {
6546                 inode_dec_link_count(inode);
6547                 discard_new_inode(inode);
6548         }
6549         btrfs_btree_balance_dirty(fs_info);
6550         return err;
6551 }
6552
6553 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6554                       struct dentry *dentry)
6555 {
6556         struct btrfs_trans_handle *trans = NULL;
6557         struct btrfs_root *root = BTRFS_I(dir)->root;
6558         struct inode *inode = d_inode(old_dentry);
6559         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6560         u64 index;
6561         int err;
6562         int drop_inode = 0;
6563
6564         /* do not allow sys_link's with other subvols of the same device */
6565         if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
6566                 return -EXDEV;
6567
6568         if (inode->i_nlink >= BTRFS_LINK_MAX)
6569                 return -EMLINK;
6570
6571         err = btrfs_set_inode_index(BTRFS_I(dir), &index);
6572         if (err)
6573                 goto fail;
6574
6575         /*
6576          * 2 items for inode and inode ref
6577          * 2 items for dir items
6578          * 1 item for parent inode
6579          * 1 item for orphan item deletion if O_TMPFILE
6580          */
6581         trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
6582         if (IS_ERR(trans)) {
6583                 err = PTR_ERR(trans);
6584                 trans = NULL;
6585                 goto fail;
6586         }
6587
6588         /* There are several dir indexes for this inode, clear the cache. */
6589         BTRFS_I(inode)->dir_index = 0ULL;
6590         inc_nlink(inode);
6591         inode_inc_iversion(inode);
6592         inode->i_ctime = current_time(inode);
6593         ihold(inode);
6594         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6595
6596         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6597                         1, index);
6598
6599         if (err) {
6600                 drop_inode = 1;
6601         } else {
6602                 struct dentry *parent = dentry->d_parent;
6603                 int ret;
6604
6605                 err = btrfs_update_inode(trans, root, inode);
6606                 if (err)
6607                         goto fail;
6608                 if (inode->i_nlink == 1) {
6609                         /*
6610                          * If new hard link count is 1, it's a file created
6611                          * with open(2) O_TMPFILE flag.
6612                          */
6613                         err = btrfs_orphan_del(trans, BTRFS_I(inode));
6614                         if (err)
6615                                 goto fail;
6616                 }
6617                 d_instantiate(dentry, inode);
6618                 ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent,
6619                                          true, NULL);
6620                 if (ret == BTRFS_NEED_TRANS_COMMIT) {
6621                         err = btrfs_commit_transaction(trans);
6622                         trans = NULL;
6623                 }
6624         }
6625
6626 fail:
6627         if (trans)
6628                 btrfs_end_transaction(trans);
6629         if (drop_inode) {
6630                 inode_dec_link_count(inode);
6631                 iput(inode);
6632         }
6633         btrfs_btree_balance_dirty(fs_info);
6634         return err;
6635 }
6636
6637 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6638 {
6639         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6640         struct inode *inode = NULL;
6641         struct btrfs_trans_handle *trans;
6642         struct btrfs_root *root = BTRFS_I(dir)->root;
6643         int err = 0;
6644         int drop_on_err = 0;
6645         u64 objectid = 0;
6646         u64 index = 0;
6647
6648         /*
6649          * 2 items for inode and ref
6650          * 2 items for dir items
6651          * 1 for xattr if selinux is on
6652          */
6653         trans = btrfs_start_transaction(root, 5);
6654         if (IS_ERR(trans))
6655                 return PTR_ERR(trans);
6656
6657         err = btrfs_find_free_ino(root, &objectid);
6658         if (err)
6659                 goto out_fail;
6660
6661         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6662                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6663                         S_IFDIR | mode, &index);
6664         if (IS_ERR(inode)) {
6665                 err = PTR_ERR(inode);
6666                 inode = NULL;
6667                 goto out_fail;
6668         }
6669
6670         drop_on_err = 1;
6671         /* these must be set before we unlock the inode */
6672         inode->i_op = &btrfs_dir_inode_operations;
6673         inode->i_fop = &btrfs_dir_file_operations;
6674
6675         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6676         if (err)
6677                 goto out_fail;
6678
6679         btrfs_i_size_write(BTRFS_I(inode), 0);
6680         err = btrfs_update_inode(trans, root, inode);
6681         if (err)
6682                 goto out_fail;
6683
6684         err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
6685                         dentry->d_name.name,
6686                         dentry->d_name.len, 0, index);
6687         if (err)
6688                 goto out_fail;
6689
6690         d_instantiate_new(dentry, inode);
6691         drop_on_err = 0;
6692
6693 out_fail:
6694         btrfs_end_transaction(trans);
6695         if (err && inode) {
6696                 inode_dec_link_count(inode);
6697                 discard_new_inode(inode);
6698         }
6699         btrfs_btree_balance_dirty(fs_info);
6700         return err;
6701 }
6702
6703 static noinline int uncompress_inline(struct btrfs_path *path,
6704                                       struct page *page,
6705                                       size_t pg_offset, u64 extent_offset,
6706                                       struct btrfs_file_extent_item *item)
6707 {
6708         int ret;
6709         struct extent_buffer *leaf = path->nodes[0];
6710         char *tmp;
6711         size_t max_size;
6712         unsigned long inline_size;
6713         unsigned long ptr;
6714         int compress_type;
6715
6716         WARN_ON(pg_offset != 0);
6717         compress_type = btrfs_file_extent_compression(leaf, item);
6718         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6719         inline_size = btrfs_file_extent_inline_item_len(leaf,
6720                                         btrfs_item_nr(path->slots[0]));
6721         tmp = kmalloc(inline_size, GFP_NOFS);
6722         if (!tmp)
6723                 return -ENOMEM;
6724         ptr = btrfs_file_extent_inline_start(item);
6725
6726         read_extent_buffer(leaf, tmp, ptr, inline_size);
6727
6728         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6729         ret = btrfs_decompress(compress_type, tmp, page,
6730                                extent_offset, inline_size, max_size);
6731
6732         /*
6733          * decompression code contains a memset to fill in any space between the end
6734          * of the uncompressed data and the end of max_size in case the decompressed
6735          * data ends up shorter than ram_bytes.  That doesn't cover the hole between
6736          * the end of an inline extent and the beginning of the next block, so we
6737          * cover that region here.
6738          */
6739
6740         if (max_size + pg_offset < PAGE_SIZE) {
6741                 char *map = kmap(page);
6742                 memset(map + pg_offset + max_size, 0, PAGE_SIZE - max_size - pg_offset);
6743                 kunmap(page);
6744         }
6745         kfree(tmp);
6746         return ret;
6747 }
6748
6749 /*
6750  * a bit scary, this does extent mapping from logical file offset to the disk.
6751  * the ugly parts come from merging extents from the disk with the in-ram
6752  * representation.  This gets more complex because of the data=ordered code,
6753  * where the in-ram extents might be locked pending data=ordered completion.
6754  *
6755  * This also copies inline extents directly into the page.
6756  */
6757 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
6758                                     struct page *page,
6759                                     size_t pg_offset, u64 start, u64 len,
6760                                     int create)
6761 {
6762         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6763         int ret;
6764         int err = 0;
6765         u64 extent_start = 0;
6766         u64 extent_end = 0;
6767         u64 objectid = btrfs_ino(inode);
6768         u32 found_type;
6769         struct btrfs_path *path = NULL;
6770         struct btrfs_root *root = inode->root;
6771         struct btrfs_file_extent_item *item;
6772         struct extent_buffer *leaf;
6773         struct btrfs_key found_key;
6774         struct extent_map *em = NULL;
6775         struct extent_map_tree *em_tree = &inode->extent_tree;
6776         struct extent_io_tree *io_tree = &inode->io_tree;
6777         const bool new_inline = !page || create;
6778
6779         read_lock(&em_tree->lock);
6780         em = lookup_extent_mapping(em_tree, start, len);
6781         if (em)
6782                 em->bdev = fs_info->fs_devices->latest_bdev;
6783         read_unlock(&em_tree->lock);
6784
6785         if (em) {
6786                 if (em->start > start || em->start + em->len <= start)
6787                         free_extent_map(em);
6788                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6789                         free_extent_map(em);
6790                 else
6791                         goto out;
6792         }
6793         em = alloc_extent_map();
6794         if (!em) {
6795                 err = -ENOMEM;
6796                 goto out;
6797         }
6798         em->bdev = fs_info->fs_devices->latest_bdev;
6799         em->start = EXTENT_MAP_HOLE;
6800         em->orig_start = EXTENT_MAP_HOLE;
6801         em->len = (u64)-1;
6802         em->block_len = (u64)-1;
6803
6804         path = btrfs_alloc_path();
6805         if (!path) {
6806                 err = -ENOMEM;
6807                 goto out;
6808         }
6809
6810         /* Chances are we'll be called again, so go ahead and do readahead */
6811         path->reada = READA_FORWARD;
6812
6813         /*
6814          * Unless we're going to uncompress the inline extent, no sleep would
6815          * happen.
6816          */
6817         path->leave_spinning = 1;
6818
6819         ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
6820         if (ret < 0) {
6821                 err = ret;
6822                 goto out;
6823         }
6824
6825         if (ret != 0) {
6826                 if (path->slots[0] == 0)
6827                         goto not_found;
6828                 path->slots[0]--;
6829         }
6830
6831         leaf = path->nodes[0];
6832         item = btrfs_item_ptr(leaf, path->slots[0],
6833                               struct btrfs_file_extent_item);
6834         /* are we inside the extent that was found? */
6835         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6836         found_type = found_key.type;
6837         if (found_key.objectid != objectid ||
6838             found_type != BTRFS_EXTENT_DATA_KEY) {
6839                 /*
6840                  * If we backup past the first extent we want to move forward
6841                  * and see if there is an extent in front of us, otherwise we'll
6842                  * say there is a hole for our whole search range which can
6843                  * cause problems.
6844                  */
6845                 extent_end = start;
6846                 goto next;
6847         }
6848
6849         found_type = btrfs_file_extent_type(leaf, item);
6850         extent_start = found_key.offset;
6851         if (found_type == BTRFS_FILE_EXTENT_REG ||
6852             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6853                 extent_end = extent_start +
6854                        btrfs_file_extent_num_bytes(leaf, item);
6855
6856                 trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
6857                                                        extent_start);
6858         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6859                 size_t size;
6860
6861                 size = btrfs_file_extent_ram_bytes(leaf, item);
6862                 extent_end = ALIGN(extent_start + size,
6863                                    fs_info->sectorsize);
6864
6865                 trace_btrfs_get_extent_show_fi_inline(inode, leaf, item,
6866                                                       path->slots[0],
6867                                                       extent_start);
6868         }
6869 next:
6870         if (start >= extent_end) {
6871                 path->slots[0]++;
6872                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6873                         ret = btrfs_next_leaf(root, path);
6874                         if (ret < 0) {
6875                                 err = ret;
6876                                 goto out;
6877                         }
6878                         if (ret > 0)
6879                                 goto not_found;
6880                         leaf = path->nodes[0];
6881                 }
6882                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6883                 if (found_key.objectid != objectid ||
6884                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6885                         goto not_found;
6886                 if (start + len <= found_key.offset)
6887                         goto not_found;
6888                 if (start > found_key.offset)
6889                         goto next;
6890                 em->start = start;
6891                 em->orig_start = start;
6892                 em->len = found_key.offset - start;
6893                 goto not_found_em;
6894         }
6895
6896         btrfs_extent_item_to_extent_map(inode, path, item,
6897                         new_inline, em);
6898
6899         if (found_type == BTRFS_FILE_EXTENT_REG ||
6900             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6901                 goto insert;
6902         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6903                 unsigned long ptr;
6904                 char *map;
6905                 size_t size;
6906                 size_t extent_offset;
6907                 size_t copy_size;
6908
6909                 if (new_inline)
6910                         goto out;
6911
6912                 size = btrfs_file_extent_ram_bytes(leaf, item);
6913                 extent_offset = page_offset(page) + pg_offset - extent_start;
6914                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6915                                   size - extent_offset);
6916                 em->start = extent_start + extent_offset;
6917                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6918                 em->orig_block_len = em->len;
6919                 em->orig_start = em->start;
6920                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6921
6922                 btrfs_set_path_blocking(path);
6923                 if (!PageUptodate(page)) {
6924                         if (btrfs_file_extent_compression(leaf, item) !=
6925                             BTRFS_COMPRESS_NONE) {
6926                                 ret = uncompress_inline(path, page, pg_offset,
6927                                                         extent_offset, item);
6928                                 if (ret) {
6929                                         err = ret;
6930                                         goto out;
6931                                 }
6932                         } else {
6933                                 map = kmap(page);
6934                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6935                                                    copy_size);
6936                                 if (pg_offset + copy_size < PAGE_SIZE) {
6937                                         memset(map + pg_offset + copy_size, 0,
6938                                                PAGE_SIZE - pg_offset -
6939                                                copy_size);
6940                                 }
6941                                 kunmap(page);
6942                         }
6943                         flush_dcache_page(page);
6944                 }
6945                 set_extent_uptodate(io_tree, em->start,
6946                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6947                 goto insert;
6948         }
6949 not_found:
6950         em->start = start;
6951         em->orig_start = start;
6952         em->len = len;
6953 not_found_em:
6954         em->block_start = EXTENT_MAP_HOLE;
6955 insert:
6956         btrfs_release_path(path);
6957         if (em->start > start || extent_map_end(em) <= start) {
6958                 btrfs_err(fs_info,
6959                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
6960                           em->start, em->len, start, len);
6961                 err = -EIO;
6962                 goto out;
6963         }
6964
6965         err = 0;
6966         write_lock(&em_tree->lock);
6967         err = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
6968         write_unlock(&em_tree->lock);
6969 out:
6970         btrfs_free_path(path);
6971
6972         trace_btrfs_get_extent(root, inode, em);
6973
6974         if (err) {
6975                 free_extent_map(em);
6976                 return ERR_PTR(err);
6977         }
6978         BUG_ON(!em); /* Error is always set */
6979         return em;
6980 }
6981
6982 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
6983                 struct page *page,
6984                 size_t pg_offset, u64 start, u64 len,
6985                 int create)
6986 {
6987         struct extent_map *em;
6988         struct extent_map *hole_em = NULL;
6989         u64 range_start = start;
6990         u64 end;
6991         u64 found;
6992         u64 found_end;
6993         int err = 0;
6994
6995         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6996         if (IS_ERR(em))
6997                 return em;
6998         /*
6999          * If our em maps to:
7000          * - a hole or
7001          * - a pre-alloc extent,
7002          * there might actually be delalloc bytes behind it.
7003          */
7004         if (em->block_start != EXTENT_MAP_HOLE &&
7005             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7006                 return em;
7007         else
7008                 hole_em = em;
7009
7010         /* check to see if we've wrapped (len == -1 or similar) */
7011         end = start + len;
7012         if (end < start)
7013                 end = (u64)-1;
7014         else
7015                 end -= 1;
7016
7017         em = NULL;
7018
7019         /* ok, we didn't find anything, lets look for delalloc */
7020         found = count_range_bits(&inode->io_tree, &range_start,
7021                                  end, len, EXTENT_DELALLOC, 1);
7022         found_end = range_start + found;
7023         if (found_end < range_start)
7024                 found_end = (u64)-1;
7025
7026         /*
7027          * we didn't find anything useful, return
7028          * the original results from get_extent()
7029          */
7030         if (range_start > end || found_end <= start) {
7031                 em = hole_em;
7032                 hole_em = NULL;
7033                 goto out;
7034         }
7035
7036         /* adjust the range_start to make sure it doesn't
7037          * go backwards from the start they passed in
7038          */
7039         range_start = max(start, range_start);
7040         found = found_end - range_start;
7041
7042         if (found > 0) {
7043                 u64 hole_start = start;
7044                 u64 hole_len = len;
7045
7046                 em = alloc_extent_map();
7047                 if (!em) {
7048                         err = -ENOMEM;
7049                         goto out;
7050                 }
7051                 /*
7052                  * when btrfs_get_extent can't find anything it
7053                  * returns one huge hole
7054                  *
7055                  * make sure what it found really fits our range, and
7056                  * adjust to make sure it is based on the start from
7057                  * the caller
7058                  */
7059                 if (hole_em) {
7060                         u64 calc_end = extent_map_end(hole_em);
7061
7062                         if (calc_end <= start || (hole_em->start > end)) {
7063                                 free_extent_map(hole_em);
7064                                 hole_em = NULL;
7065                         } else {
7066                                 hole_start = max(hole_em->start, start);
7067                                 hole_len = calc_end - hole_start;
7068                         }
7069                 }
7070                 em->bdev = NULL;
7071                 if (hole_em && range_start > hole_start) {
7072                         /* our hole starts before our delalloc, so we
7073                          * have to return just the parts of the hole
7074                          * that go until  the delalloc starts
7075                          */
7076                         em->len = min(hole_len,
7077                                       range_start - hole_start);
7078                         em->start = hole_start;
7079                         em->orig_start = hole_start;
7080                         /*
7081                          * don't adjust block start at all,
7082                          * it is fixed at EXTENT_MAP_HOLE
7083                          */
7084                         em->block_start = hole_em->block_start;
7085                         em->block_len = hole_len;
7086                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7087                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7088                 } else {
7089                         em->start = range_start;
7090                         em->len = found;
7091                         em->orig_start = range_start;
7092                         em->block_start = EXTENT_MAP_DELALLOC;
7093                         em->block_len = found;
7094                 }
7095         } else {
7096                 return hole_em;
7097         }
7098 out:
7099
7100         free_extent_map(hole_em);
7101         if (err) {
7102                 free_extent_map(em);
7103                 return ERR_PTR(err);
7104         }
7105         return em;
7106 }
7107
7108 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7109                                                   const u64 start,
7110                                                   const u64 len,
7111                                                   const u64 orig_start,
7112                                                   const u64 block_start,
7113                                                   const u64 block_len,
7114                                                   const u64 orig_block_len,
7115                                                   const u64 ram_bytes,
7116                                                   const int type)
7117 {
7118         struct extent_map *em = NULL;
7119         int ret;
7120
7121         if (type != BTRFS_ORDERED_NOCOW) {
7122                 em = create_io_em(inode, start, len, orig_start,
7123                                   block_start, block_len, orig_block_len,
7124                                   ram_bytes,
7125                                   BTRFS_COMPRESS_NONE, /* compress_type */
7126                                   type);
7127                 if (IS_ERR(em))
7128                         goto out;
7129         }
7130         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7131                                            len, block_len, type);
7132         if (ret) {
7133                 if (em) {
7134                         free_extent_map(em);
7135                         btrfs_drop_extent_cache(BTRFS_I(inode), start,
7136                                                 start + len - 1, 0);
7137                 }
7138                 em = ERR_PTR(ret);
7139         }
7140  out:
7141
7142         return em;
7143 }
7144
7145 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7146                                                   u64 start, u64 len)
7147 {
7148         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7149         struct btrfs_root *root = BTRFS_I(inode)->root;
7150         struct extent_map *em;
7151         struct btrfs_key ins;
7152         u64 alloc_hint;
7153         int ret;
7154
7155         alloc_hint = get_extent_allocation_hint(inode, start, len);
7156         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
7157                                    0, alloc_hint, &ins, 1, 1);
7158         if (ret)
7159                 return ERR_PTR(ret);
7160
7161         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7162                                      ins.objectid, ins.offset, ins.offset,
7163                                      ins.offset, BTRFS_ORDERED_REGULAR);
7164         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
7165         if (IS_ERR(em))
7166                 btrfs_free_reserved_extent(fs_info, ins.objectid,
7167                                            ins.offset, 1);
7168
7169         return em;
7170 }
7171
7172 /*
7173  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7174  * block must be cow'd
7175  */
7176 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7177                               u64 *orig_start, u64 *orig_block_len,
7178                               u64 *ram_bytes)
7179 {
7180         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7181         struct btrfs_path *path;
7182         int ret;
7183         struct extent_buffer *leaf;
7184         struct btrfs_root *root = BTRFS_I(inode)->root;
7185         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7186         struct btrfs_file_extent_item *fi;
7187         struct btrfs_key key;
7188         u64 disk_bytenr;
7189         u64 backref_offset;
7190         u64 extent_end;
7191         u64 num_bytes;
7192         int slot;
7193         int found_type;
7194         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7195
7196         path = btrfs_alloc_path();
7197         if (!path)
7198                 return -ENOMEM;
7199
7200         ret = btrfs_lookup_file_extent(NULL, root, path,
7201                         btrfs_ino(BTRFS_I(inode)), offset, 0);
7202         if (ret < 0)
7203                 goto out;
7204
7205         slot = path->slots[0];
7206         if (ret == 1) {
7207                 if (slot == 0) {
7208                         /* can't find the item, must cow */
7209                         ret = 0;
7210                         goto out;
7211                 }
7212                 slot--;
7213         }
7214         ret = 0;
7215         leaf = path->nodes[0];
7216         btrfs_item_key_to_cpu(leaf, &key, slot);
7217         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
7218             key.type != BTRFS_EXTENT_DATA_KEY) {
7219                 /* not our file or wrong item type, must cow */
7220                 goto out;
7221         }
7222
7223         if (key.offset > offset) {
7224                 /* Wrong offset, must cow */
7225                 goto out;
7226         }
7227
7228         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7229         found_type = btrfs_file_extent_type(leaf, fi);
7230         if (found_type != BTRFS_FILE_EXTENT_REG &&
7231             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7232                 /* not a regular extent, must cow */
7233                 goto out;
7234         }
7235
7236         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7237                 goto out;
7238
7239         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7240         if (extent_end <= offset)
7241                 goto out;
7242
7243         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7244         if (disk_bytenr == 0)
7245                 goto out;
7246
7247         if (btrfs_file_extent_compression(leaf, fi) ||
7248             btrfs_file_extent_encryption(leaf, fi) ||
7249             btrfs_file_extent_other_encoding(leaf, fi))
7250                 goto out;
7251
7252         /*
7253          * Do the same check as in btrfs_cross_ref_exist but without the
7254          * unnecessary search.
7255          */
7256         if (btrfs_file_extent_generation(leaf, fi) <=
7257             btrfs_root_last_snapshot(&root->root_item))
7258                 goto out;
7259
7260         backref_offset = btrfs_file_extent_offset(leaf, fi);
7261
7262         if (orig_start) {
7263                 *orig_start = key.offset - backref_offset;
7264                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7265                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7266         }
7267
7268         if (btrfs_extent_readonly(fs_info, disk_bytenr))
7269                 goto out;
7270
7271         num_bytes = min(offset + *len, extent_end) - offset;
7272         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7273                 u64 range_end;
7274
7275                 range_end = round_up(offset + num_bytes,
7276                                      root->fs_info->sectorsize) - 1;
7277                 ret = test_range_bit(io_tree, offset, range_end,
7278                                      EXTENT_DELALLOC, 0, NULL);
7279                 if (ret) {
7280                         ret = -EAGAIN;
7281                         goto out;
7282                 }
7283         }
7284
7285         btrfs_release_path(path);
7286
7287         /*
7288          * look for other files referencing this extent, if we
7289          * find any we must cow
7290          */
7291
7292         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
7293                                     key.offset - backref_offset, disk_bytenr);
7294         if (ret) {
7295                 ret = 0;
7296                 goto out;
7297         }
7298
7299         /*
7300          * adjust disk_bytenr and num_bytes to cover just the bytes
7301          * in this extent we are about to write.  If there
7302          * are any csums in that range we have to cow in order
7303          * to keep the csums correct
7304          */
7305         disk_bytenr += backref_offset;
7306         disk_bytenr += offset - key.offset;
7307         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
7308                 goto out;
7309         /*
7310          * all of the above have passed, it is safe to overwrite this extent
7311          * without cow
7312          */
7313         *len = num_bytes;
7314         ret = 1;
7315 out:
7316         btrfs_free_path(path);
7317         return ret;
7318 }
7319
7320 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7321                               struct extent_state **cached_state, int writing)
7322 {
7323         struct btrfs_ordered_extent *ordered;
7324         int ret = 0;
7325
7326         while (1) {
7327                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7328                                  cached_state);
7329                 /*
7330                  * We're concerned with the entire range that we're going to be
7331                  * doing DIO to, so we need to make sure there's no ordered
7332                  * extents in this range.
7333                  */
7334                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), lockstart,
7335                                                      lockend - lockstart + 1);
7336
7337                 /*
7338                  * We need to make sure there are no buffered pages in this
7339                  * range either, we could have raced between the invalidate in
7340                  * generic_file_direct_write and locking the extent.  The
7341                  * invalidate needs to happen so that reads after a write do not
7342                  * get stale data.
7343                  */
7344                 if (!ordered &&
7345                     (!writing || !filemap_range_has_page(inode->i_mapping,
7346                                                          lockstart, lockend)))
7347                         break;
7348
7349                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7350                                      cached_state);
7351
7352                 if (ordered) {
7353                         /*
7354                          * If we are doing a DIO read and the ordered extent we
7355                          * found is for a buffered write, we can not wait for it
7356                          * to complete and retry, because if we do so we can
7357                          * deadlock with concurrent buffered writes on page
7358                          * locks. This happens only if our DIO read covers more
7359                          * than one extent map, if at this point has already
7360                          * created an ordered extent for a previous extent map
7361                          * and locked its range in the inode's io tree, and a
7362                          * concurrent write against that previous extent map's
7363                          * range and this range started (we unlock the ranges
7364                          * in the io tree only when the bios complete and
7365                          * buffered writes always lock pages before attempting
7366                          * to lock range in the io tree).
7367                          */
7368                         if (writing ||
7369                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7370                                 btrfs_start_ordered_extent(inode, ordered, 1);
7371                         else
7372                                 ret = -ENOTBLK;
7373                         btrfs_put_ordered_extent(ordered);
7374                 } else {
7375                         /*
7376                          * We could trigger writeback for this range (and wait
7377                          * for it to complete) and then invalidate the pages for
7378                          * this range (through invalidate_inode_pages2_range()),
7379                          * but that can lead us to a deadlock with a concurrent
7380                          * call to readpages() (a buffered read or a defrag call
7381                          * triggered a readahead) on a page lock due to an
7382                          * ordered dio extent we created before but did not have
7383                          * yet a corresponding bio submitted (whence it can not
7384                          * complete), which makes readpages() wait for that
7385                          * ordered extent to complete while holding a lock on
7386                          * that page.
7387                          */
7388                         ret = -ENOTBLK;
7389                 }
7390
7391                 if (ret)
7392                         break;
7393
7394                 cond_resched();
7395         }
7396
7397         return ret;
7398 }
7399
7400 /* The callers of this must take lock_extent() */
7401 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
7402                                        u64 orig_start, u64 block_start,
7403                                        u64 block_len, u64 orig_block_len,
7404                                        u64 ram_bytes, int compress_type,
7405                                        int type)
7406 {
7407         struct extent_map_tree *em_tree;
7408         struct extent_map *em;
7409         struct btrfs_root *root = BTRFS_I(inode)->root;
7410         int ret;
7411
7412         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
7413                type == BTRFS_ORDERED_COMPRESSED ||
7414                type == BTRFS_ORDERED_NOCOW ||
7415                type == BTRFS_ORDERED_REGULAR);
7416
7417         em_tree = &BTRFS_I(inode)->extent_tree;
7418         em = alloc_extent_map();
7419         if (!em)
7420                 return ERR_PTR(-ENOMEM);
7421
7422         em->start = start;
7423         em->orig_start = orig_start;
7424         em->len = len;
7425         em->block_len = block_len;
7426         em->block_start = block_start;
7427         em->bdev = root->fs_info->fs_devices->latest_bdev;
7428         em->orig_block_len = orig_block_len;
7429         em->ram_bytes = ram_bytes;
7430         em->generation = -1;
7431         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7432         if (type == BTRFS_ORDERED_PREALLOC) {
7433                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7434         } else if (type == BTRFS_ORDERED_COMPRESSED) {
7435                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
7436                 em->compress_type = compress_type;
7437         }
7438
7439         do {
7440                 btrfs_drop_extent_cache(BTRFS_I(inode), em->start,
7441                                 em->start + em->len - 1, 0);
7442                 write_lock(&em_tree->lock);
7443                 ret = add_extent_mapping(em_tree, em, 1);
7444                 write_unlock(&em_tree->lock);
7445                 /*
7446                  * The caller has taken lock_extent(), who could race with us
7447                  * to add em?
7448                  */
7449         } while (ret == -EEXIST);
7450
7451         if (ret) {
7452                 free_extent_map(em);
7453                 return ERR_PTR(ret);
7454         }
7455
7456         /* em got 2 refs now, callers needs to do free_extent_map once. */
7457         return em;
7458 }
7459
7460
7461 static int btrfs_get_blocks_direct_read(struct extent_map *em,
7462                                         struct buffer_head *bh_result,
7463                                         struct inode *inode,
7464                                         u64 start, u64 len)
7465 {
7466         if (em->block_start == EXTENT_MAP_HOLE ||
7467                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7468                 return -ENOENT;
7469
7470         len = min(len, em->len - (start - em->start));
7471
7472         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7473                 inode->i_blkbits;
7474         bh_result->b_size = len;
7475         bh_result->b_bdev = em->bdev;
7476         set_buffer_mapped(bh_result);
7477
7478         return 0;
7479 }
7480
7481 static int btrfs_get_blocks_direct_write(struct extent_map **map,
7482                                          struct buffer_head *bh_result,
7483                                          struct inode *inode,
7484                                          struct btrfs_dio_data *dio_data,
7485                                          u64 start, u64 len)
7486 {
7487         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7488         struct extent_map *em = *map;
7489         int ret = 0;
7490
7491         /*
7492          * We don't allocate a new extent in the following cases
7493          *
7494          * 1) The inode is marked as NODATACOW. In this case we'll just use the
7495          * existing extent.
7496          * 2) The extent is marked as PREALLOC. We're good to go here and can
7497          * just use the extent.
7498          *
7499          */
7500         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7501             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7502              em->block_start != EXTENT_MAP_HOLE)) {
7503                 int type;
7504                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7505
7506                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7507                         type = BTRFS_ORDERED_PREALLOC;
7508                 else
7509                         type = BTRFS_ORDERED_NOCOW;
7510                 len = min(len, em->len - (start - em->start));
7511                 block_start = em->block_start + (start - em->start);
7512
7513                 if (can_nocow_extent(inode, start, &len, &orig_start,
7514                                      &orig_block_len, &ram_bytes) == 1 &&
7515                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7516                         struct extent_map *em2;
7517
7518                         em2 = btrfs_create_dio_extent(inode, start, len,
7519                                                       orig_start, block_start,
7520                                                       len, orig_block_len,
7521                                                       ram_bytes, type);
7522                         btrfs_dec_nocow_writers(fs_info, block_start);
7523                         if (type == BTRFS_ORDERED_PREALLOC) {
7524                                 free_extent_map(em);
7525                                 *map = em = em2;
7526                         }
7527
7528                         if (em2 && IS_ERR(em2)) {
7529                                 ret = PTR_ERR(em2);
7530                                 goto out;
7531                         }
7532                         /*
7533                          * For inode marked NODATACOW or extent marked PREALLOC,
7534                          * use the existing or preallocated extent, so does not
7535                          * need to adjust btrfs_space_info's bytes_may_use.
7536                          */
7537                         btrfs_free_reserved_data_space_noquota(inode, start,
7538                                                                len);
7539                         goto skip_cow;
7540                 }
7541         }
7542
7543         /* this will cow the extent */
7544         len = bh_result->b_size;
7545         free_extent_map(em);
7546         *map = em = btrfs_new_extent_direct(inode, start, len);
7547         if (IS_ERR(em)) {
7548                 ret = PTR_ERR(em);
7549                 goto out;
7550         }
7551
7552         len = min(len, em->len - (start - em->start));
7553
7554 skip_cow:
7555         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7556                 inode->i_blkbits;
7557         bh_result->b_size = len;
7558         bh_result->b_bdev = em->bdev;
7559         set_buffer_mapped(bh_result);
7560
7561         if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7562                 set_buffer_new(bh_result);
7563
7564         /*
7565          * Need to update the i_size under the extent lock so buffered
7566          * readers will get the updated i_size when we unlock.
7567          */
7568         if (!dio_data->overwrite && start + len > i_size_read(inode))
7569                 i_size_write(inode, start + len);
7570
7571         WARN_ON(dio_data->reserve < len);
7572         dio_data->reserve -= len;
7573         dio_data->unsubmitted_oe_range_end = start + len;
7574         current->journal_info = dio_data;
7575 out:
7576         return ret;
7577 }
7578
7579 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7580                                    struct buffer_head *bh_result, int create)
7581 {
7582         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7583         struct extent_map *em;
7584         struct extent_state *cached_state = NULL;
7585         struct btrfs_dio_data *dio_data = NULL;
7586         u64 start = iblock << inode->i_blkbits;
7587         u64 lockstart, lockend;
7588         u64 len = bh_result->b_size;
7589         int unlock_bits = EXTENT_LOCKED;
7590         int ret = 0;
7591
7592         if (create)
7593                 unlock_bits |= EXTENT_DIRTY;
7594         else
7595                 len = min_t(u64, len, fs_info->sectorsize);
7596
7597         lockstart = start;
7598         lockend = start + len - 1;
7599
7600         if (current->journal_info) {
7601                 /*
7602                  * Need to pull our outstanding extents and set journal_info to NULL so
7603                  * that anything that needs to check if there's a transaction doesn't get
7604                  * confused.
7605                  */
7606                 dio_data = current->journal_info;
7607                 current->journal_info = NULL;
7608         }
7609
7610         /*
7611          * If this errors out it's because we couldn't invalidate pagecache for
7612          * this range and we need to fallback to buffered.
7613          */
7614         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7615                                create)) {
7616                 ret = -ENOTBLK;
7617                 goto err;
7618         }
7619
7620         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
7621         if (IS_ERR(em)) {
7622                 ret = PTR_ERR(em);
7623                 goto unlock_err;
7624         }
7625
7626         /*
7627          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7628          * io.  INLINE is special, and we could probably kludge it in here, but
7629          * it's still buffered so for safety lets just fall back to the generic
7630          * buffered path.
7631          *
7632          * For COMPRESSED we _have_ to read the entire extent in so we can
7633          * decompress it, so there will be buffering required no matter what we
7634          * do, so go ahead and fallback to buffered.
7635          *
7636          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7637          * to buffered IO.  Don't blame me, this is the price we pay for using
7638          * the generic code.
7639          */
7640         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7641             em->block_start == EXTENT_MAP_INLINE) {
7642                 free_extent_map(em);
7643                 ret = -ENOTBLK;
7644                 goto unlock_err;
7645         }
7646
7647         if (create) {
7648                 ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
7649                                                     dio_data, start, len);
7650                 if (ret < 0)
7651                         goto unlock_err;
7652
7653                 /* clear and unlock the entire range */
7654                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7655                                  unlock_bits, 1, 0, &cached_state);
7656         } else {
7657                 ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
7658                                                    start, len);
7659                 /* Can be negative only if we read from a hole */
7660                 if (ret < 0) {
7661                         ret = 0;
7662                         free_extent_map(em);
7663                         goto unlock_err;
7664                 }
7665                 /*
7666                  * We need to unlock only the end area that we aren't using.
7667                  * The rest is going to be unlocked by the endio routine.
7668                  */
7669                 lockstart = start + bh_result->b_size;
7670                 if (lockstart < lockend) {
7671                         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7672                                          lockend, unlock_bits, 1, 0,
7673                                          &cached_state);
7674                 } else {
7675                         free_extent_state(cached_state);
7676                 }
7677         }
7678
7679         free_extent_map(em);
7680
7681         return 0;
7682
7683 unlock_err:
7684         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7685                          unlock_bits, 1, 0, &cached_state);
7686 err:
7687         if (dio_data)
7688                 current->journal_info = dio_data;
7689         return ret;
7690 }
7691
7692 static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
7693                                                  struct bio *bio,
7694                                                  int mirror_num)
7695 {
7696         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7697         blk_status_t ret;
7698
7699         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7700
7701         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7702         if (ret)
7703                 return ret;
7704
7705         ret = btrfs_map_bio(fs_info, bio, mirror_num, 0);
7706
7707         return ret;
7708 }
7709
7710 static int btrfs_check_dio_repairable(struct inode *inode,
7711                                       struct bio *failed_bio,
7712                                       struct io_failure_record *failrec,
7713                                       int failed_mirror)
7714 {
7715         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7716         int num_copies;
7717
7718         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7719         if (num_copies == 1) {
7720                 /*
7721                  * we only have a single copy of the data, so don't bother with
7722                  * all the retry and error correction code that follows. no
7723                  * matter what the error is, it is very likely to persist.
7724                  */
7725                 btrfs_debug(fs_info,
7726                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7727                         num_copies, failrec->this_mirror, failed_mirror);
7728                 return 0;
7729         }
7730
7731         failrec->failed_mirror = failed_mirror;
7732         failrec->this_mirror++;
7733         if (failrec->this_mirror == failed_mirror)
7734                 failrec->this_mirror++;
7735
7736         if (failrec->this_mirror > num_copies) {
7737                 btrfs_debug(fs_info,
7738                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7739                         num_copies, failrec->this_mirror, failed_mirror);
7740                 return 0;
7741         }
7742
7743         return 1;
7744 }
7745
7746 static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
7747                                    struct page *page, unsigned int pgoff,
7748                                    u64 start, u64 end, int failed_mirror,
7749                                    bio_end_io_t *repair_endio, void *repair_arg)
7750 {
7751         struct io_failure_record *failrec;
7752         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7753         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
7754         struct bio *bio;
7755         int isector;
7756         unsigned int read_mode = 0;
7757         int segs;
7758         int ret;
7759         blk_status_t status;
7760         struct bio_vec bvec;
7761
7762         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7763
7764         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7765         if (ret)
7766                 return errno_to_blk_status(ret);
7767
7768         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7769                                          failed_mirror);
7770         if (!ret) {
7771                 free_io_failure(failure_tree, io_tree, failrec);
7772                 return BLK_STS_IOERR;
7773         }
7774
7775         segs = bio_segments(failed_bio);
7776         bio_get_first_bvec(failed_bio, &bvec);
7777         if (segs > 1 ||
7778             (bvec.bv_len > btrfs_inode_sectorsize(inode)))
7779                 read_mode |= REQ_FAILFAST_DEV;
7780
7781         isector = start - btrfs_io_bio(failed_bio)->logical;
7782         isector >>= inode->i_sb->s_blocksize_bits;
7783         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7784                                 pgoff, isector, repair_endio, repair_arg);
7785         bio->bi_opf = REQ_OP_READ | read_mode;
7786
7787         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7788                     "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
7789                     read_mode, failrec->this_mirror, failrec->in_validation);
7790
7791         status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7792         if (status) {
7793                 free_io_failure(failure_tree, io_tree, failrec);
7794                 bio_put(bio);
7795         }
7796
7797         return status;
7798 }
7799
7800 struct btrfs_retry_complete {
7801         struct completion done;
7802         struct inode *inode;
7803         u64 start;
7804         int uptodate;
7805 };
7806
7807 static void btrfs_retry_endio_nocsum(struct bio *bio)
7808 {
7809         struct btrfs_retry_complete *done = bio->bi_private;
7810         struct inode *inode = done->inode;
7811         struct bio_vec *bvec;
7812         struct extent_io_tree *io_tree, *failure_tree;
7813         int i;
7814
7815         if (bio->bi_status)
7816                 goto end;
7817
7818         ASSERT(bio->bi_vcnt == 1);
7819         io_tree = &BTRFS_I(inode)->io_tree;
7820         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7821         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode));
7822
7823         done->uptodate = 1;
7824         ASSERT(!bio_flagged(bio, BIO_CLONED));
7825         bio_for_each_segment_all(bvec, bio, i)
7826                 clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
7827                                  io_tree, done->start, bvec->bv_page,
7828                                  btrfs_ino(BTRFS_I(inode)), 0);
7829 end:
7830         complete(&done->done);
7831         bio_put(bio);
7832 }
7833
7834 static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode,
7835                                                 struct btrfs_io_bio *io_bio)
7836 {
7837         struct btrfs_fs_info *fs_info;
7838         struct bio_vec bvec;
7839         struct bvec_iter iter;
7840         struct btrfs_retry_complete done;
7841         u64 start;
7842         unsigned int pgoff;
7843         u32 sectorsize;
7844         int nr_sectors;
7845         blk_status_t ret;
7846         blk_status_t err = BLK_STS_OK;
7847
7848         fs_info = BTRFS_I(inode)->root->fs_info;
7849         sectorsize = fs_info->sectorsize;
7850
7851         start = io_bio->logical;
7852         done.inode = inode;
7853         io_bio->bio.bi_iter = io_bio->iter;
7854
7855         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7856                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7857                 pgoff = bvec.bv_offset;
7858
7859 next_block_or_try_again:
7860                 done.uptodate = 0;
7861                 done.start = start;
7862                 init_completion(&done.done);
7863
7864                 ret = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7865                                 pgoff, start, start + sectorsize - 1,
7866                                 io_bio->mirror_num,
7867                                 btrfs_retry_endio_nocsum, &done);
7868                 if (ret) {
7869                         err = ret;
7870                         goto next;
7871                 }
7872
7873                 wait_for_completion_io(&done.done);
7874
7875                 if (!done.uptodate) {
7876                         /* We might have another mirror, so try again */
7877                         goto next_block_or_try_again;
7878                 }
7879
7880 next:
7881                 start += sectorsize;
7882
7883                 nr_sectors--;
7884                 if (nr_sectors) {
7885                         pgoff += sectorsize;
7886                         ASSERT(pgoff < PAGE_SIZE);
7887                         goto next_block_or_try_again;
7888                 }
7889         }
7890
7891         return err;
7892 }
7893
7894 static void btrfs_retry_endio(struct bio *bio)
7895 {
7896         struct btrfs_retry_complete *done = bio->bi_private;
7897         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7898         struct extent_io_tree *io_tree, *failure_tree;
7899         struct inode *inode = done->inode;
7900         struct bio_vec *bvec;
7901         int uptodate;
7902         int ret;
7903         int i;
7904
7905         if (bio->bi_status)
7906                 goto end;
7907
7908         uptodate = 1;
7909
7910         ASSERT(bio->bi_vcnt == 1);
7911         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode));
7912
7913         io_tree = &BTRFS_I(inode)->io_tree;
7914         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7915
7916         ASSERT(!bio_flagged(bio, BIO_CLONED));
7917         bio_for_each_segment_all(bvec, bio, i) {
7918                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7919                                              bvec->bv_offset, done->start,
7920                                              bvec->bv_len);
7921                 if (!ret)
7922                         clean_io_failure(BTRFS_I(inode)->root->fs_info,
7923                                          failure_tree, io_tree, done->start,
7924                                          bvec->bv_page,
7925                                          btrfs_ino(BTRFS_I(inode)),
7926                                          bvec->bv_offset);
7927                 else
7928                         uptodate = 0;
7929         }
7930
7931         done->uptodate = uptodate;
7932 end:
7933         complete(&done->done);
7934         bio_put(bio);
7935 }
7936
7937 static blk_status_t __btrfs_subio_endio_read(struct inode *inode,
7938                 struct btrfs_io_bio *io_bio, blk_status_t err)
7939 {
7940         struct btrfs_fs_info *fs_info;
7941         struct bio_vec bvec;
7942         struct bvec_iter iter;
7943         struct btrfs_retry_complete done;
7944         u64 start;
7945         u64 offset = 0;
7946         u32 sectorsize;
7947         int nr_sectors;
7948         unsigned int pgoff;
7949         int csum_pos;
7950         bool uptodate = (err == 0);
7951         int ret;
7952         blk_status_t status;
7953
7954         fs_info = BTRFS_I(inode)->root->fs_info;
7955         sectorsize = fs_info->sectorsize;
7956
7957         err = BLK_STS_OK;
7958         start = io_bio->logical;
7959         done.inode = inode;
7960         io_bio->bio.bi_iter = io_bio->iter;
7961
7962         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7963                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7964
7965                 pgoff = bvec.bv_offset;
7966 next_block:
7967                 if (uptodate) {
7968                         csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
7969                         ret = __readpage_endio_check(inode, io_bio, csum_pos,
7970                                         bvec.bv_page, pgoff, start, sectorsize);
7971                         if (likely(!ret))
7972                                 goto next;
7973                 }
7974 try_again:
7975                 done.uptodate = 0;
7976                 done.start = start;
7977                 init_completion(&done.done);
7978
7979                 status = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7980                                         pgoff, start, start + sectorsize - 1,
7981                                         io_bio->mirror_num, btrfs_retry_endio,
7982                                         &done);
7983                 if (status) {
7984                         err = status;
7985                         goto next;
7986                 }
7987
7988                 wait_for_completion_io(&done.done);
7989
7990                 if (!done.uptodate) {
7991                         /* We might have another mirror, so try again */
7992                         goto try_again;
7993                 }
7994 next:
7995                 offset += sectorsize;
7996                 start += sectorsize;
7997
7998                 ASSERT(nr_sectors);
7999
8000                 nr_sectors--;
8001                 if (nr_sectors) {
8002                         pgoff += sectorsize;
8003                         ASSERT(pgoff < PAGE_SIZE);
8004                         goto next_block;
8005                 }
8006         }
8007
8008         return err;
8009 }
8010
8011 static blk_status_t btrfs_subio_endio_read(struct inode *inode,
8012                 struct btrfs_io_bio *io_bio, blk_status_t err)
8013 {
8014         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8015
8016         if (skip_csum) {
8017                 if (unlikely(err))
8018                         return __btrfs_correct_data_nocsum(inode, io_bio);
8019                 else
8020                         return BLK_STS_OK;
8021         } else {
8022                 return __btrfs_subio_endio_read(inode, io_bio, err);
8023         }
8024 }
8025
8026 static void btrfs_endio_direct_read(struct bio *bio)
8027 {
8028         struct btrfs_dio_private *dip = bio->bi_private;
8029         struct inode *inode = dip->inode;
8030         struct bio *dio_bio;
8031         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8032         blk_status_t err = bio->bi_status;
8033
8034         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8035                 err = btrfs_subio_endio_read(inode, io_bio, err);
8036
8037         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8038                       dip->logical_offset + dip->bytes - 1);
8039         dio_bio = dip->dio_bio;
8040
8041         kfree(dip);
8042
8043         dio_bio->bi_status = err;
8044         dio_end_io(dio_bio);
8045
8046         if (io_bio->end_io)
8047                 io_bio->end_io(io_bio, blk_status_to_errno(err));
8048         bio_put(bio);
8049 }
8050
8051 static void __endio_write_update_ordered(struct inode *inode,
8052                                          const u64 offset, const u64 bytes,
8053                                          const bool uptodate)
8054 {
8055         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8056         struct btrfs_ordered_extent *ordered = NULL;
8057         struct btrfs_workqueue *wq;
8058         btrfs_work_func_t func;
8059         u64 ordered_offset = offset;
8060         u64 ordered_bytes = bytes;
8061         u64 last_offset;
8062
8063         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
8064                 wq = fs_info->endio_freespace_worker;
8065                 func = btrfs_freespace_write_helper;
8066         } else {
8067                 wq = fs_info->endio_write_workers;
8068                 func = btrfs_endio_write_helper;
8069         }
8070
8071         while (ordered_offset < offset + bytes) {
8072                 last_offset = ordered_offset;
8073                 if (btrfs_dec_test_first_ordered_pending(inode, &ordered,
8074                                                            &ordered_offset,
8075                                                            ordered_bytes,
8076                                                            uptodate)) {
8077                         btrfs_init_work(&ordered->work, func,
8078                                         finish_ordered_fn,
8079                                         NULL, NULL);
8080                         btrfs_queue_work(wq, &ordered->work);
8081                 }
8082                 /*
8083                  * If btrfs_dec_test_ordered_pending does not find any ordered
8084                  * extent in the range, we can exit.
8085                  */
8086                 if (ordered_offset == last_offset)
8087                         return;
8088                 /*
8089                  * Our bio might span multiple ordered extents. In this case
8090                  * we keep goin until we have accounted the whole dio.
8091                  */
8092                 if (ordered_offset < offset + bytes) {
8093                         ordered_bytes = offset + bytes - ordered_offset;
8094                         ordered = NULL;
8095                 }
8096         }
8097 }
8098
8099 static void btrfs_endio_direct_write(struct bio *bio)
8100 {
8101         struct btrfs_dio_private *dip = bio->bi_private;
8102         struct bio *dio_bio = dip->dio_bio;
8103
8104         __endio_write_update_ordered(dip->inode, dip->logical_offset,
8105                                      dip->bytes, !bio->bi_status);
8106
8107         kfree(dip);
8108
8109         dio_bio->bi_status = bio->bi_status;
8110         dio_end_io(dio_bio);
8111         bio_put(bio);
8112 }
8113
8114 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
8115                                     struct bio *bio, u64 offset)
8116 {
8117         struct inode *inode = private_data;
8118         blk_status_t ret;
8119         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
8120         BUG_ON(ret); /* -ENOMEM */
8121         return 0;
8122 }
8123
8124 static void btrfs_end_dio_bio(struct bio *bio)
8125 {
8126         struct btrfs_dio_private *dip = bio->bi_private;
8127         blk_status_t err = bio->bi_status;
8128
8129         if (err)
8130                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8131                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8132                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
8133                            bio->bi_opf,
8134                            (unsigned long long)bio->bi_iter.bi_sector,
8135                            bio->bi_iter.bi_size, err);
8136
8137         if (dip->subio_endio)
8138                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8139
8140         if (err) {
8141                 /*
8142                  * We want to perceive the errors flag being set before
8143                  * decrementing the reference count. We don't need a barrier
8144                  * since atomic operations with a return value are fully
8145                  * ordered as per atomic_t.txt
8146                  */
8147                 dip->errors = 1;
8148         }
8149
8150         /* if there are more bios still pending for this dio, just exit */
8151         if (!atomic_dec_and_test(&dip->pending_bios))
8152                 goto out;
8153
8154         if (dip->errors) {
8155                 bio_io_error(dip->orig_bio);
8156         } else {
8157                 dip->dio_bio->bi_status = BLK_STS_OK;
8158                 bio_endio(dip->orig_bio);
8159         }
8160 out:
8161         bio_put(bio);
8162 }
8163
8164 static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
8165                                                  struct btrfs_dio_private *dip,
8166                                                  struct bio *bio,
8167                                                  u64 file_offset)
8168 {
8169         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8170         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8171         blk_status_t ret;
8172
8173         /*
8174          * We load all the csum data we need when we submit
8175          * the first bio to reduce the csum tree search and
8176          * contention.
8177          */
8178         if (dip->logical_offset == file_offset) {
8179                 ret = btrfs_lookup_bio_sums_dio(inode, dip->orig_bio,
8180                                                 file_offset);
8181                 if (ret)
8182                         return ret;
8183         }
8184
8185         if (bio == dip->orig_bio)
8186                 return 0;
8187
8188         file_offset -= dip->logical_offset;
8189         file_offset >>= inode->i_sb->s_blocksize_bits;
8190         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8191
8192         return 0;
8193 }
8194
8195 static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
8196                 struct inode *inode, u64 file_offset, int async_submit)
8197 {
8198         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8199         struct btrfs_dio_private *dip = bio->bi_private;
8200         bool write = bio_op(bio) == REQ_OP_WRITE;
8201         blk_status_t ret;
8202
8203         /* Check btrfs_submit_bio_hook() for rules about async submit. */
8204         if (async_submit)
8205                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8206
8207         if (!write) {
8208                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
8209                 if (ret)
8210                         goto err;
8211         }
8212
8213         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
8214                 goto map;
8215
8216         if (write && async_submit) {
8217                 ret = btrfs_wq_submit_bio(fs_info, bio, 0, 0,
8218                                           file_offset, inode,
8219                                           btrfs_submit_bio_start_direct_io);
8220                 goto err;
8221         } else if (write) {
8222                 /*
8223                  * If we aren't doing async submit, calculate the csum of the
8224                  * bio now.
8225                  */
8226                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
8227                 if (ret)
8228                         goto err;
8229         } else {
8230                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
8231                                                      file_offset);
8232                 if (ret)
8233                         goto err;
8234         }
8235 map:
8236         ret = btrfs_map_bio(fs_info, bio, 0, 0);
8237 err:
8238         return ret;
8239 }
8240
8241 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
8242 {
8243         struct inode *inode = dip->inode;
8244         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8245         struct bio *bio;
8246         struct bio *orig_bio = dip->orig_bio;
8247         u64 start_sector = orig_bio->bi_iter.bi_sector;
8248         u64 file_offset = dip->logical_offset;
8249         u64 map_length;
8250         int async_submit = 0;
8251         u64 submit_len;
8252         int clone_offset = 0;
8253         int clone_len;
8254         int ret;
8255         blk_status_t status;
8256
8257         map_length = orig_bio->bi_iter.bi_size;
8258         submit_len = map_length;
8259         ret = btrfs_map_block(fs_info, btrfs_op(orig_bio), start_sector << 9,
8260                               &map_length, NULL, 0);
8261         if (ret)
8262                 return -EIO;
8263
8264         if (map_length >= submit_len) {
8265                 bio = orig_bio;
8266                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8267                 goto submit;
8268         }
8269
8270         /* async crcs make it difficult to collect full stripe writes. */
8271         if (btrfs_data_alloc_profile(fs_info) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8272                 async_submit = 0;
8273         else
8274                 async_submit = 1;
8275
8276         /* bio split */
8277         ASSERT(map_length <= INT_MAX);
8278         atomic_inc(&dip->pending_bios);
8279         do {
8280                 clone_len = min_t(int, submit_len, map_length);
8281
8282                 /*
8283                  * This will never fail as it's passing GPF_NOFS and
8284                  * the allocation is backed by btrfs_bioset.
8285                  */
8286                 bio = btrfs_bio_clone_partial(orig_bio, clone_offset,
8287                                               clone_len);
8288                 bio->bi_private = dip;
8289                 bio->bi_end_io = btrfs_end_dio_bio;
8290                 btrfs_io_bio(bio)->logical = file_offset;
8291
8292                 ASSERT(submit_len >= clone_len);
8293                 submit_len -= clone_len;
8294                 if (submit_len == 0)
8295                         break;
8296
8297                 /*
8298                  * Increase the count before we submit the bio so we know
8299                  * the end IO handler won't happen before we increase the
8300                  * count. Otherwise, the dip might get freed before we're
8301                  * done setting it up.
8302                  */
8303                 atomic_inc(&dip->pending_bios);
8304
8305                 status = btrfs_submit_dio_bio(bio, inode, file_offset,
8306                                                 async_submit);
8307                 if (status) {
8308                         bio_put(bio);
8309                         atomic_dec(&dip->pending_bios);
8310                         goto out_err;
8311                 }
8312
8313                 clone_offset += clone_len;
8314                 start_sector += clone_len >> 9;
8315                 file_offset += clone_len;
8316
8317                 map_length = submit_len;
8318                 ret = btrfs_map_block(fs_info, btrfs_op(orig_bio),
8319                                       start_sector << 9, &map_length, NULL, 0);
8320                 if (ret)
8321                         goto out_err;
8322         } while (submit_len > 0);
8323
8324 submit:
8325         status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit);
8326         if (!status)
8327                 return 0;
8328
8329         bio_put(bio);
8330 out_err:
8331         dip->errors = 1;
8332         /*
8333          * Before atomic variable goto zero, we must  make sure dip->errors is
8334          * perceived to be set. This ordering is ensured by the fact that an
8335          * atomic operations with a return value are fully ordered as per
8336          * atomic_t.txt
8337          */
8338         if (atomic_dec_and_test(&dip->pending_bios))
8339                 bio_io_error(dip->orig_bio);
8340
8341         /* bio_end_io() will handle error, so we needn't return it */
8342         return 0;
8343 }
8344
8345 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8346                                 loff_t file_offset)
8347 {
8348         struct btrfs_dio_private *dip = NULL;
8349         struct bio *bio = NULL;
8350         struct btrfs_io_bio *io_bio;
8351         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8352         int ret = 0;
8353
8354         bio = btrfs_bio_clone(dio_bio);
8355
8356         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8357         if (!dip) {
8358                 ret = -ENOMEM;
8359                 goto free_ordered;
8360         }
8361
8362         dip->private = dio_bio->bi_private;
8363         dip->inode = inode;
8364         dip->logical_offset = file_offset;
8365         dip->bytes = dio_bio->bi_iter.bi_size;
8366         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8367         bio->bi_private = dip;
8368         dip->orig_bio = bio;
8369         dip->dio_bio = dio_bio;
8370         atomic_set(&dip->pending_bios, 0);
8371         io_bio = btrfs_io_bio(bio);
8372         io_bio->logical = file_offset;
8373
8374         if (write) {
8375                 bio->bi_end_io = btrfs_endio_direct_write;
8376         } else {
8377                 bio->bi_end_io = btrfs_endio_direct_read;
8378                 dip->subio_endio = btrfs_subio_endio_read;
8379         }
8380
8381         /*
8382          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8383          * even if we fail to submit a bio, because in such case we do the
8384          * corresponding error handling below and it must not be done a second
8385          * time by btrfs_direct_IO().
8386          */
8387         if (write) {
8388                 struct btrfs_dio_data *dio_data = current->journal_info;
8389
8390                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8391                         dip->bytes;
8392                 dio_data->unsubmitted_oe_range_start =
8393                         dio_data->unsubmitted_oe_range_end;
8394         }
8395
8396         ret = btrfs_submit_direct_hook(dip);
8397         if (!ret)
8398                 return;
8399
8400         if (io_bio->end_io)
8401                 io_bio->end_io(io_bio, ret);
8402
8403 free_ordered:
8404         /*
8405          * If we arrived here it means either we failed to submit the dip
8406          * or we either failed to clone the dio_bio or failed to allocate the
8407          * dip. If we cloned the dio_bio and allocated the dip, we can just
8408          * call bio_endio against our io_bio so that we get proper resource
8409          * cleanup if we fail to submit the dip, otherwise, we must do the
8410          * same as btrfs_endio_direct_[write|read] because we can't call these
8411          * callbacks - they require an allocated dip and a clone of dio_bio.
8412          */
8413         if (bio && dip) {
8414                 bio_io_error(bio);
8415                 /*
8416                  * The end io callbacks free our dip, do the final put on bio
8417                  * and all the cleanup and final put for dio_bio (through
8418                  * dio_end_io()).
8419                  */
8420                 dip = NULL;
8421                 bio = NULL;
8422         } else {
8423                 if (write)
8424                         __endio_write_update_ordered(inode,
8425                                                 file_offset,
8426                                                 dio_bio->bi_iter.bi_size,
8427                                                 false);
8428                 else
8429                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8430                               file_offset + dio_bio->bi_iter.bi_size - 1);
8431
8432                 dio_bio->bi_status = BLK_STS_IOERR;
8433                 /*
8434                  * Releases and cleans up our dio_bio, no need to bio_put()
8435                  * nor bio_endio()/bio_io_error() against dio_bio.
8436                  */
8437                 dio_end_io(dio_bio);
8438         }
8439         if (bio)
8440                 bio_put(bio);
8441         kfree(dip);
8442 }
8443
8444 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
8445                                const struct iov_iter *iter, loff_t offset)
8446 {
8447         int seg;
8448         int i;
8449         unsigned int blocksize_mask = fs_info->sectorsize - 1;
8450         ssize_t retval = -EINVAL;
8451
8452         if (offset & blocksize_mask)
8453                 goto out;
8454
8455         if (iov_iter_alignment(iter) & blocksize_mask)
8456                 goto out;
8457
8458         /* If this is a write we don't need to check anymore */
8459         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
8460                 return 0;
8461         /*
8462          * Check to make sure we don't have duplicate iov_base's in this
8463          * iovec, if so return EINVAL, otherwise we'll get csum errors
8464          * when reading back.
8465          */
8466         for (seg = 0; seg < iter->nr_segs; seg++) {
8467                 for (i = seg + 1; i < iter->nr_segs; i++) {
8468                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8469                                 goto out;
8470                 }
8471         }
8472         retval = 0;
8473 out:
8474         return retval;
8475 }
8476
8477 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8478 {
8479         struct file *file = iocb->ki_filp;
8480         struct inode *inode = file->f_mapping->host;
8481         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8482         struct btrfs_dio_data dio_data = { 0 };
8483         struct extent_changeset *data_reserved = NULL;
8484         loff_t offset = iocb->ki_pos;
8485         size_t count = 0;
8486         int flags = 0;
8487         bool wakeup = true;
8488         bool relock = false;
8489         ssize_t ret;
8490
8491         if (check_direct_IO(fs_info, iter, offset))
8492                 return 0;
8493
8494         inode_dio_begin(inode);
8495
8496         /*
8497          * The generic stuff only does filemap_write_and_wait_range, which
8498          * isn't enough if we've written compressed pages to this area, so
8499          * we need to flush the dirty pages again to make absolutely sure
8500          * that any outstanding dirty pages are on disk.
8501          */
8502         count = iov_iter_count(iter);
8503         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8504                      &BTRFS_I(inode)->runtime_flags))
8505                 filemap_fdatawrite_range(inode->i_mapping, offset,
8506                                          offset + count - 1);
8507
8508         if (iov_iter_rw(iter) == WRITE) {
8509                 /*
8510                  * If the write DIO is beyond the EOF, we need update
8511                  * the isize, but it is protected by i_mutex. So we can
8512                  * not unlock the i_mutex at this case.
8513                  */
8514                 if (offset + count <= inode->i_size) {
8515                         dio_data.overwrite = 1;
8516                         inode_unlock(inode);
8517                         relock = true;
8518                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
8519                         ret = -EAGAIN;
8520                         goto out;
8521                 }
8522                 ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
8523                                                    offset, count);
8524                 if (ret)
8525                         goto out;
8526
8527                 /*
8528                  * We need to know how many extents we reserved so that we can
8529                  * do the accounting properly if we go over the number we
8530                  * originally calculated.  Abuse current->journal_info for this.
8531                  */
8532                 dio_data.reserve = round_up(count,
8533                                             fs_info->sectorsize);
8534                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8535                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8536                 current->journal_info = &dio_data;
8537                 down_read(&BTRFS_I(inode)->dio_sem);
8538         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8539                                      &BTRFS_I(inode)->runtime_flags)) {
8540                 inode_dio_end(inode);
8541                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8542                 wakeup = false;
8543         }
8544
8545         ret = __blockdev_direct_IO(iocb, inode,
8546                                    fs_info->fs_devices->latest_bdev,
8547                                    iter, btrfs_get_blocks_direct, NULL,
8548                                    btrfs_submit_direct, flags);
8549         if (iov_iter_rw(iter) == WRITE) {
8550                 up_read(&BTRFS_I(inode)->dio_sem);
8551                 current->journal_info = NULL;
8552                 if (ret < 0 && ret != -EIOCBQUEUED) {
8553                         if (dio_data.reserve)
8554                                 btrfs_delalloc_release_space(inode, data_reserved,
8555                                         offset, dio_data.reserve, true);
8556                         /*
8557                          * On error we might have left some ordered extents
8558                          * without submitting corresponding bios for them, so
8559                          * cleanup them up to avoid other tasks getting them
8560                          * and waiting for them to complete forever.
8561                          */
8562                         if (dio_data.unsubmitted_oe_range_start <
8563                             dio_data.unsubmitted_oe_range_end)
8564                                 __endio_write_update_ordered(inode,
8565                                         dio_data.unsubmitted_oe_range_start,
8566                                         dio_data.unsubmitted_oe_range_end -
8567                                         dio_data.unsubmitted_oe_range_start,
8568                                         false);
8569                 } else if (ret >= 0 && (size_t)ret < count)
8570                         btrfs_delalloc_release_space(inode, data_reserved,
8571                                         offset, count - (size_t)ret, true);
8572                 btrfs_delalloc_release_extents(BTRFS_I(inode), count, false);
8573         }
8574 out:
8575         if (wakeup)
8576                 inode_dio_end(inode);
8577         if (relock)
8578                 inode_lock(inode);
8579
8580         extent_changeset_free(data_reserved);
8581         return ret;
8582 }
8583
8584 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8585
8586 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8587                 __u64 start, __u64 len)
8588 {
8589         int     ret;
8590
8591         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8592         if (ret)
8593                 return ret;
8594
8595         return extent_fiemap(inode, fieinfo, start, len);
8596 }
8597
8598 int btrfs_readpage(struct file *file, struct page *page)
8599 {
8600         struct extent_io_tree *tree;
8601         tree = &BTRFS_I(page->mapping->host)->io_tree;
8602         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8603 }
8604
8605 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8606 {
8607         struct inode *inode = page->mapping->host;
8608         int ret;
8609
8610         if (current->flags & PF_MEMALLOC) {
8611                 redirty_page_for_writepage(wbc, page);
8612                 unlock_page(page);
8613                 return 0;
8614         }
8615
8616         /*
8617          * If we are under memory pressure we will call this directly from the
8618          * VM, we need to make sure we have the inode referenced for the ordered
8619          * extent.  If not just return like we didn't do anything.
8620          */
8621         if (!igrab(inode)) {
8622                 redirty_page_for_writepage(wbc, page);
8623                 return AOP_WRITEPAGE_ACTIVATE;
8624         }
8625         ret = extent_write_full_page(page, wbc);
8626         btrfs_add_delayed_iput(inode);
8627         return ret;
8628 }
8629
8630 static int btrfs_writepages(struct address_space *mapping,
8631                             struct writeback_control *wbc)
8632 {
8633         return extent_writepages(mapping, wbc);
8634 }
8635
8636 static int
8637 btrfs_readpages(struct file *file, struct address_space *mapping,
8638                 struct list_head *pages, unsigned nr_pages)
8639 {
8640         return extent_readpages(mapping, pages, nr_pages);
8641 }
8642
8643 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8644 {
8645         int ret = try_release_extent_mapping(page, gfp_flags);
8646         if (ret == 1) {
8647                 ClearPagePrivate(page);
8648                 set_page_private(page, 0);
8649                 put_page(page);
8650         }
8651         return ret;
8652 }
8653
8654 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8655 {
8656         if (PageWriteback(page) || PageDirty(page))
8657                 return 0;
8658         return __btrfs_releasepage(page, gfp_flags);
8659 }
8660
8661 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8662                                  unsigned int length)
8663 {
8664         struct inode *inode = page->mapping->host;
8665         struct extent_io_tree *tree;
8666         struct btrfs_ordered_extent *ordered;
8667         struct extent_state *cached_state = NULL;
8668         u64 page_start = page_offset(page);
8669         u64 page_end = page_start + PAGE_SIZE - 1;
8670         u64 start;
8671         u64 end;
8672         int inode_evicting = inode->i_state & I_FREEING;
8673
8674         /*
8675          * we have the page locked, so new writeback can't start,
8676          * and the dirty bit won't be cleared while we are here.
8677          *
8678          * Wait for IO on this page so that we can safely clear
8679          * the PagePrivate2 bit and do ordered accounting
8680          */
8681         wait_on_page_writeback(page);
8682
8683         tree = &BTRFS_I(inode)->io_tree;
8684         if (offset) {
8685                 btrfs_releasepage(page, GFP_NOFS);
8686                 return;
8687         }
8688
8689         if (!inode_evicting)
8690                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8691 again:
8692         start = page_start;
8693         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
8694                                         page_end - start + 1);
8695         if (ordered) {
8696                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8697                 /*
8698                  * IO on this page will never be started, so we need
8699                  * to account for any ordered extents now
8700                  */
8701                 if (!inode_evicting)
8702                         clear_extent_bit(tree, start, end,
8703                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8704                                          EXTENT_DELALLOC_NEW |
8705                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8706                                          EXTENT_DEFRAG, 1, 0, &cached_state);
8707                 /*
8708                  * whoever cleared the private bit is responsible
8709                  * for the finish_ordered_io
8710                  */
8711                 if (TestClearPagePrivate2(page)) {
8712                         struct btrfs_ordered_inode_tree *tree;
8713                         u64 new_len;
8714
8715                         tree = &BTRFS_I(inode)->ordered_tree;
8716
8717                         spin_lock_irq(&tree->lock);
8718                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8719                         new_len = start - ordered->file_offset;
8720                         if (new_len < ordered->truncated_len)
8721                                 ordered->truncated_len = new_len;
8722                         spin_unlock_irq(&tree->lock);
8723
8724                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8725                                                            start,
8726                                                            end - start + 1, 1))
8727                                 btrfs_finish_ordered_io(ordered);
8728                 }
8729                 btrfs_put_ordered_extent(ordered);
8730                 if (!inode_evicting) {
8731                         cached_state = NULL;
8732                         lock_extent_bits(tree, start, end,
8733                                          &cached_state);
8734                 }
8735
8736                 start = end + 1;
8737                 if (start < page_end)
8738                         goto again;
8739         }
8740
8741         /*
8742          * Qgroup reserved space handler
8743          * Page here will be either
8744          * 1) Already written to disk
8745          *    In this case, its reserved space is released from data rsv map
8746          *    and will be freed by delayed_ref handler finally.
8747          *    So even we call qgroup_free_data(), it won't decrease reserved
8748          *    space.
8749          * 2) Not written to disk
8750          *    This means the reserved space should be freed here. However,
8751          *    if a truncate invalidates the page (by clearing PageDirty)
8752          *    and the page is accounted for while allocating extent
8753          *    in btrfs_check_data_free_space() we let delayed_ref to
8754          *    free the entire extent.
8755          */
8756         if (PageDirty(page))
8757                 btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
8758         if (!inode_evicting) {
8759                 clear_extent_bit(tree, page_start, page_end,
8760                                  EXTENT_LOCKED | EXTENT_DIRTY |
8761                                  EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8762                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
8763                                  &cached_state);
8764
8765                 __btrfs_releasepage(page, GFP_NOFS);
8766         }
8767
8768         ClearPageChecked(page);
8769         if (PagePrivate(page)) {
8770                 ClearPagePrivate(page);
8771                 set_page_private(page, 0);
8772                 put_page(page);
8773         }
8774 }
8775
8776 /*
8777  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8778  * called from a page fault handler when a page is first dirtied. Hence we must
8779  * be careful to check for EOF conditions here. We set the page up correctly
8780  * for a written page which means we get ENOSPC checking when writing into
8781  * holes and correct delalloc and unwritten extent mapping on filesystems that
8782  * support these features.
8783  *
8784  * We are not allowed to take the i_mutex here so we have to play games to
8785  * protect against truncate races as the page could now be beyond EOF.  Because
8786  * truncate_setsize() writes the inode size before removing pages, once we have
8787  * the page lock we can determine safely if the page is beyond EOF. If it is not
8788  * beyond EOF, then the page is guaranteed safe against truncation until we
8789  * unlock the page.
8790  */
8791 vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
8792 {
8793         struct page *page = vmf->page;
8794         struct inode *inode = file_inode(vmf->vma->vm_file);
8795         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8796         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8797         struct btrfs_ordered_extent *ordered;
8798         struct extent_state *cached_state = NULL;
8799         struct extent_changeset *data_reserved = NULL;
8800         char *kaddr;
8801         unsigned long zero_start;
8802         loff_t size;
8803         vm_fault_t ret;
8804         int ret2;
8805         int reserved = 0;
8806         u64 reserved_space;
8807         u64 page_start;
8808         u64 page_end;
8809         u64 end;
8810
8811         reserved_space = PAGE_SIZE;
8812
8813         sb_start_pagefault(inode->i_sb);
8814         page_start = page_offset(page);
8815         page_end = page_start + PAGE_SIZE - 1;
8816         end = page_end;
8817
8818         /*
8819          * Reserving delalloc space after obtaining the page lock can lead to
8820          * deadlock. For example, if a dirty page is locked by this function
8821          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8822          * dirty page write out, then the btrfs_writepage() function could
8823          * end up waiting indefinitely to get a lock on the page currently
8824          * being processed by btrfs_page_mkwrite() function.
8825          */
8826         ret2 = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
8827                                            reserved_space);
8828         if (!ret2) {
8829                 ret2 = file_update_time(vmf->vma->vm_file);
8830                 reserved = 1;
8831         }
8832         if (ret2) {
8833                 ret = vmf_error(ret2);
8834                 if (reserved)
8835                         goto out;
8836                 goto out_noreserve;
8837         }
8838
8839         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8840 again:
8841         lock_page(page);
8842         size = i_size_read(inode);
8843
8844         if ((page->mapping != inode->i_mapping) ||
8845             (page_start >= size)) {
8846                 /* page got truncated out from underneath us */
8847                 goto out_unlock;
8848         }
8849         wait_on_page_writeback(page);
8850
8851         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8852         set_page_extent_mapped(page);
8853
8854         /*
8855          * we can't set the delalloc bits if there are pending ordered
8856          * extents.  Drop our locks and wait for them to finish
8857          */
8858         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
8859                         PAGE_SIZE);
8860         if (ordered) {
8861                 unlock_extent_cached(io_tree, page_start, page_end,
8862                                      &cached_state);
8863                 unlock_page(page);
8864                 btrfs_start_ordered_extent(inode, ordered, 1);
8865                 btrfs_put_ordered_extent(ordered);
8866                 goto again;
8867         }
8868
8869         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8870                 reserved_space = round_up(size - page_start,
8871                                           fs_info->sectorsize);
8872                 if (reserved_space < PAGE_SIZE) {
8873                         end = page_start + reserved_space - 1;
8874                         btrfs_delalloc_release_space(inode, data_reserved,
8875                                         page_start, PAGE_SIZE - reserved_space,
8876                                         true);
8877                 }
8878         }
8879
8880         /*
8881          * page_mkwrite gets called when the page is firstly dirtied after it's
8882          * faulted in, but write(2) could also dirty a page and set delalloc
8883          * bits, thus in this case for space account reason, we still need to
8884          * clear any delalloc bits within this page range since we have to
8885          * reserve data&meta space before lock_page() (see above comments).
8886          */
8887         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8888                           EXTENT_DIRTY | EXTENT_DELALLOC |
8889                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
8890                           0, 0, &cached_state);
8891
8892         ret2 = btrfs_set_extent_delalloc(inode, page_start, end, 0,
8893                                         &cached_state, 0);
8894         if (ret2) {
8895                 unlock_extent_cached(io_tree, page_start, page_end,
8896                                      &cached_state);
8897                 ret = VM_FAULT_SIGBUS;
8898                 goto out_unlock;
8899         }
8900         ret2 = 0;
8901
8902         /* page is wholly or partially inside EOF */
8903         if (page_start + PAGE_SIZE > size)
8904                 zero_start = size & ~PAGE_MASK;
8905         else
8906                 zero_start = PAGE_SIZE;
8907
8908         if (zero_start != PAGE_SIZE) {
8909                 kaddr = kmap(page);
8910                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8911                 flush_dcache_page(page);
8912                 kunmap(page);
8913         }
8914         ClearPageChecked(page);
8915         set_page_dirty(page);
8916         SetPageUptodate(page);
8917
8918         BTRFS_I(inode)->last_trans = fs_info->generation;
8919         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8920         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8921
8922         unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
8923
8924         if (!ret2) {
8925                 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true);
8926                 sb_end_pagefault(inode->i_sb);
8927                 extent_changeset_free(data_reserved);
8928                 return VM_FAULT_LOCKED;
8929         }
8930
8931 out_unlock:
8932         unlock_page(page);
8933 out:
8934         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, (ret != 0));
8935         btrfs_delalloc_release_space(inode, data_reserved, page_start,
8936                                      reserved_space, (ret != 0));
8937 out_noreserve:
8938         sb_end_pagefault(inode->i_sb);
8939         extent_changeset_free(data_reserved);
8940         return ret;
8941 }
8942
8943 static int btrfs_truncate(struct inode *inode, bool skip_writeback)
8944 {
8945         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8946         struct btrfs_root *root = BTRFS_I(inode)->root;
8947         struct btrfs_block_rsv *rsv;
8948         int ret;
8949         struct btrfs_trans_handle *trans;
8950         u64 mask = fs_info->sectorsize - 1;
8951         u64 min_size = btrfs_calc_trunc_metadata_size(fs_info, 1);
8952
8953         if (!skip_writeback) {
8954                 ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8955                                                (u64)-1);
8956                 if (ret)
8957                         return ret;
8958         }
8959
8960         /*
8961          * Yes ladies and gentlemen, this is indeed ugly.  We have a couple of
8962          * things going on here:
8963          *
8964          * 1) We need to reserve space to update our inode.
8965          *
8966          * 2) We need to have something to cache all the space that is going to
8967          * be free'd up by the truncate operation, but also have some slack
8968          * space reserved in case it uses space during the truncate (thank you
8969          * very much snapshotting).
8970          *
8971          * And we need these to be separate.  The fact is we can use a lot of
8972          * space doing the truncate, and we have no earthly idea how much space
8973          * we will use, so we need the truncate reservation to be separate so it
8974          * doesn't end up using space reserved for updating the inode.  We also
8975          * need to be able to stop the transaction and start a new one, which
8976          * means we need to be able to update the inode several times, and we
8977          * have no idea of knowing how many times that will be, so we can't just
8978          * reserve 1 item for the entirety of the operation, so that has to be
8979          * done separately as well.
8980          *
8981          * So that leaves us with
8982          *
8983          * 1) rsv - for the truncate reservation, which we will steal from the
8984          * transaction reservation.
8985          * 2) fs_info->trans_block_rsv - this will have 1 items worth left for
8986          * updating the inode.
8987          */
8988         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
8989         if (!rsv)
8990                 return -ENOMEM;
8991         rsv->size = min_size;
8992         rsv->failfast = 1;
8993
8994         /*
8995          * 1 for the truncate slack space
8996          * 1 for updating the inode.
8997          */
8998         trans = btrfs_start_transaction(root, 2);
8999         if (IS_ERR(trans)) {
9000                 ret = PTR_ERR(trans);
9001                 goto out;
9002         }
9003
9004         /* Migrate the slack space for the truncate to our reserve */
9005         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
9006                                       min_size, false);
9007         BUG_ON(ret);
9008
9009         /*
9010          * So if we truncate and then write and fsync we normally would just
9011          * write the extents that changed, which is a problem if we need to
9012          * first truncate that entire inode.  So set this flag so we write out
9013          * all of the extents in the inode to the sync log so we're completely
9014          * safe.
9015          */
9016         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9017         trans->block_rsv = rsv;
9018
9019         while (1) {
9020                 ret = btrfs_truncate_inode_items(trans, root, inode,
9021                                                  inode->i_size,
9022                                                  BTRFS_EXTENT_DATA_KEY);
9023                 trans->block_rsv = &fs_info->trans_block_rsv;
9024                 if (ret != -ENOSPC && ret != -EAGAIN)
9025                         break;
9026
9027                 ret = btrfs_update_inode(trans, root, inode);
9028                 if (ret)
9029                         break;
9030
9031                 btrfs_end_transaction(trans);
9032                 btrfs_btree_balance_dirty(fs_info);
9033
9034                 trans = btrfs_start_transaction(root, 2);
9035                 if (IS_ERR(trans)) {
9036                         ret = PTR_ERR(trans);
9037                         trans = NULL;
9038                         break;
9039                 }
9040
9041                 btrfs_block_rsv_release(fs_info, rsv, -1);
9042                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
9043                                               rsv, min_size, false);
9044                 BUG_ON(ret);    /* shouldn't happen */
9045                 trans->block_rsv = rsv;
9046         }
9047
9048         /*
9049          * We can't call btrfs_truncate_block inside a trans handle as we could
9050          * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
9051          * we've truncated everything except the last little bit, and can do
9052          * btrfs_truncate_block and then update the disk_i_size.
9053          */
9054         if (ret == NEED_TRUNCATE_BLOCK) {
9055                 btrfs_end_transaction(trans);
9056                 btrfs_btree_balance_dirty(fs_info);
9057
9058                 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
9059                 if (ret)
9060                         goto out;
9061                 trans = btrfs_start_transaction(root, 1);
9062                 if (IS_ERR(trans)) {
9063                         ret = PTR_ERR(trans);
9064                         goto out;
9065                 }
9066                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
9067         }
9068
9069         if (trans) {
9070                 int ret2;
9071
9072                 trans->block_rsv = &fs_info->trans_block_rsv;
9073                 ret2 = btrfs_update_inode(trans, root, inode);
9074                 if (ret2 && !ret)
9075                         ret = ret2;
9076
9077                 ret2 = btrfs_end_transaction(trans);
9078                 if (ret2 && !ret)
9079                         ret = ret2;
9080                 btrfs_btree_balance_dirty(fs_info);
9081         }
9082 out:
9083         btrfs_free_block_rsv(fs_info, rsv);
9084
9085         return ret;
9086 }
9087
9088 /*
9089  * create a new subvolume directory/inode (helper for the ioctl).
9090  */
9091 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9092                              struct btrfs_root *new_root,
9093                              struct btrfs_root *parent_root,
9094                              u64 new_dirid)
9095 {
9096         struct inode *inode;
9097         int err;
9098         u64 index = 0;
9099
9100         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9101                                 new_dirid, new_dirid,
9102                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9103                                 &index);
9104         if (IS_ERR(inode))
9105                 return PTR_ERR(inode);
9106         inode->i_op = &btrfs_dir_inode_operations;
9107         inode->i_fop = &btrfs_dir_file_operations;
9108
9109         set_nlink(inode, 1);
9110         btrfs_i_size_write(BTRFS_I(inode), 0);
9111         unlock_new_inode(inode);
9112
9113         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9114         if (err)
9115                 btrfs_err(new_root->fs_info,
9116                           "error inheriting subvolume %llu properties: %d",
9117                           new_root->root_key.objectid, err);
9118
9119         err = btrfs_update_inode(trans, new_root, inode);
9120
9121         iput(inode);
9122         return err;
9123 }
9124
9125 struct inode *btrfs_alloc_inode(struct super_block *sb)
9126 {
9127         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
9128         struct btrfs_inode *ei;
9129         struct inode *inode;
9130
9131         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_KERNEL);
9132         if (!ei)
9133                 return NULL;
9134
9135         ei->root = NULL;
9136         ei->generation = 0;
9137         ei->last_trans = 0;
9138         ei->last_sub_trans = 0;
9139         ei->logged_trans = 0;
9140         ei->delalloc_bytes = 0;
9141         ei->new_delalloc_bytes = 0;
9142         ei->defrag_bytes = 0;
9143         ei->disk_i_size = 0;
9144         ei->flags = 0;
9145         ei->csum_bytes = 0;
9146         ei->index_cnt = (u64)-1;
9147         ei->dir_index = 0;
9148         ei->last_unlink_trans = 0;
9149         ei->last_log_commit = 0;
9150
9151         spin_lock_init(&ei->lock);
9152         ei->outstanding_extents = 0;
9153         if (sb->s_magic != BTRFS_TEST_MAGIC)
9154                 btrfs_init_metadata_block_rsv(fs_info, &ei->block_rsv,
9155                                               BTRFS_BLOCK_RSV_DELALLOC);
9156         ei->runtime_flags = 0;
9157         ei->prop_compress = BTRFS_COMPRESS_NONE;
9158         ei->defrag_compress = BTRFS_COMPRESS_NONE;
9159
9160         ei->delayed_node = NULL;
9161
9162         ei->i_otime.tv_sec = 0;
9163         ei->i_otime.tv_nsec = 0;
9164
9165         inode = &ei->vfs_inode;
9166         extent_map_tree_init(&ei->extent_tree);
9167         extent_io_tree_init(&ei->io_tree, inode);
9168         extent_io_tree_init(&ei->io_failure_tree, inode);
9169         ei->io_tree.track_uptodate = 1;
9170         ei->io_failure_tree.track_uptodate = 1;
9171         atomic_set(&ei->sync_writers, 0);
9172         mutex_init(&ei->log_mutex);
9173         mutex_init(&ei->delalloc_mutex);
9174         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9175         INIT_LIST_HEAD(&ei->delalloc_inodes);
9176         INIT_LIST_HEAD(&ei->delayed_iput);
9177         RB_CLEAR_NODE(&ei->rb_node);
9178         init_rwsem(&ei->dio_sem);
9179
9180         return inode;
9181 }
9182
9183 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9184 void btrfs_test_destroy_inode(struct inode *inode)
9185 {
9186         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9187         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9188 }
9189 #endif
9190
9191 static void btrfs_i_callback(struct rcu_head *head)
9192 {
9193         struct inode *inode = container_of(head, struct inode, i_rcu);
9194         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9195 }
9196
9197 void btrfs_destroy_inode(struct inode *inode)
9198 {
9199         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9200         struct btrfs_ordered_extent *ordered;
9201         struct btrfs_root *root = BTRFS_I(inode)->root;
9202
9203         WARN_ON(!hlist_empty(&inode->i_dentry));
9204         WARN_ON(inode->i_data.nrpages);
9205         WARN_ON(BTRFS_I(inode)->block_rsv.reserved);
9206         WARN_ON(BTRFS_I(inode)->block_rsv.size);
9207         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9208         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9209         WARN_ON(BTRFS_I(inode)->new_delalloc_bytes);
9210         WARN_ON(BTRFS_I(inode)->csum_bytes);
9211         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9212
9213         /*
9214          * This can happen where we create an inode, but somebody else also
9215          * created the same inode and we need to destroy the one we already
9216          * created.
9217          */
9218         if (!root)
9219                 goto free;
9220
9221         while (1) {
9222                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9223                 if (!ordered)
9224                         break;
9225                 else {
9226                         btrfs_err(fs_info,
9227                                   "found ordered extent %llu %llu on inode cleanup",
9228                                   ordered->file_offset, ordered->len);
9229                         btrfs_remove_ordered_extent(inode, ordered);
9230                         btrfs_put_ordered_extent(ordered);
9231                         btrfs_put_ordered_extent(ordered);
9232                 }
9233         }
9234         btrfs_qgroup_check_reserved_leak(inode);
9235         inode_tree_del(inode);
9236         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
9237 free:
9238         call_rcu(&inode->i_rcu, btrfs_i_callback);
9239 }
9240
9241 int btrfs_drop_inode(struct inode *inode)
9242 {
9243         struct btrfs_root *root = BTRFS_I(inode)->root;
9244
9245         if (root == NULL)
9246                 return 1;
9247
9248         /* the snap/subvol tree is on deleting */
9249         if (btrfs_root_refs(&root->root_item) == 0)
9250                 return 1;
9251         else
9252                 return generic_drop_inode(inode);
9253 }
9254
9255 static void init_once(void *foo)
9256 {
9257         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9258
9259         inode_init_once(&ei->vfs_inode);
9260 }
9261
9262 void __cold btrfs_destroy_cachep(void)
9263 {
9264         /*
9265          * Make sure all delayed rcu free inodes are flushed before we
9266          * destroy cache.
9267          */
9268         rcu_barrier();
9269         kmem_cache_destroy(btrfs_inode_cachep);
9270         kmem_cache_destroy(btrfs_trans_handle_cachep);
9271         kmem_cache_destroy(btrfs_path_cachep);
9272         kmem_cache_destroy(btrfs_free_space_cachep);
9273 }
9274
9275 int __init btrfs_init_cachep(void)
9276 {
9277         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9278                         sizeof(struct btrfs_inode), 0,
9279                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9280                         init_once);
9281         if (!btrfs_inode_cachep)
9282                 goto fail;
9283
9284         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9285                         sizeof(struct btrfs_trans_handle), 0,
9286                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
9287         if (!btrfs_trans_handle_cachep)
9288                 goto fail;
9289
9290         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9291                         sizeof(struct btrfs_path), 0,
9292                         SLAB_MEM_SPREAD, NULL);
9293         if (!btrfs_path_cachep)
9294                 goto fail;
9295
9296         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9297                         sizeof(struct btrfs_free_space), 0,
9298                         SLAB_MEM_SPREAD, NULL);
9299         if (!btrfs_free_space_cachep)
9300                 goto fail;
9301
9302         return 0;
9303 fail:
9304         btrfs_destroy_cachep();
9305         return -ENOMEM;
9306 }
9307
9308 static int btrfs_getattr(const struct path *path, struct kstat *stat,
9309                          u32 request_mask, unsigned int flags)
9310 {
9311         u64 delalloc_bytes;
9312         struct inode *inode = d_inode(path->dentry);
9313         u32 blocksize = inode->i_sb->s_blocksize;
9314         u32 bi_flags = BTRFS_I(inode)->flags;
9315
9316         stat->result_mask |= STATX_BTIME;
9317         stat->btime.tv_sec = BTRFS_I(inode)->i_otime.tv_sec;
9318         stat->btime.tv_nsec = BTRFS_I(inode)->i_otime.tv_nsec;
9319         if (bi_flags & BTRFS_INODE_APPEND)
9320                 stat->attributes |= STATX_ATTR_APPEND;
9321         if (bi_flags & BTRFS_INODE_COMPRESS)
9322                 stat->attributes |= STATX_ATTR_COMPRESSED;
9323         if (bi_flags & BTRFS_INODE_IMMUTABLE)
9324                 stat->attributes |= STATX_ATTR_IMMUTABLE;
9325         if (bi_flags & BTRFS_INODE_NODUMP)
9326                 stat->attributes |= STATX_ATTR_NODUMP;
9327
9328         stat->attributes_mask |= (STATX_ATTR_APPEND |
9329                                   STATX_ATTR_COMPRESSED |
9330                                   STATX_ATTR_IMMUTABLE |
9331                                   STATX_ATTR_NODUMP);
9332
9333         generic_fillattr(inode, stat);
9334         stat->dev = BTRFS_I(inode)->root->anon_dev;
9335
9336         spin_lock(&BTRFS_I(inode)->lock);
9337         delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
9338         spin_unlock(&BTRFS_I(inode)->lock);
9339         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9340                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9341         return 0;
9342 }
9343
9344 static int btrfs_rename_exchange(struct inode *old_dir,
9345                               struct dentry *old_dentry,
9346                               struct inode *new_dir,
9347                               struct dentry *new_dentry)
9348 {
9349         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9350         struct btrfs_trans_handle *trans;
9351         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9352         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9353         struct inode *new_inode = new_dentry->d_inode;
9354         struct inode *old_inode = old_dentry->d_inode;
9355         struct timespec64 ctime = current_time(old_inode);
9356         struct dentry *parent;
9357         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9358         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
9359         u64 old_idx = 0;
9360         u64 new_idx = 0;
9361         u64 root_objectid;
9362         int ret;
9363         bool root_log_pinned = false;
9364         bool dest_log_pinned = false;
9365         struct btrfs_log_ctx ctx_root;
9366         struct btrfs_log_ctx ctx_dest;
9367         bool sync_log_root = false;
9368         bool sync_log_dest = false;
9369         bool commit_transaction = false;
9370
9371         /* we only allow rename subvolume link between subvolumes */
9372         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9373                 return -EXDEV;
9374
9375         btrfs_init_log_ctx(&ctx_root, old_inode);
9376         btrfs_init_log_ctx(&ctx_dest, new_inode);
9377
9378         /* close the race window with snapshot create/destroy ioctl */
9379         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9380                 down_read(&fs_info->subvol_sem);
9381         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9382                 down_read(&fs_info->subvol_sem);
9383
9384         /*
9385          * We want to reserve the absolute worst case amount of items.  So if
9386          * both inodes are subvols and we need to unlink them then that would
9387          * require 4 item modifications, but if they are both normal inodes it
9388          * would require 5 item modifications, so we'll assume their normal
9389          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9390          * should cover the worst case number of items we'll modify.
9391          */
9392         trans = btrfs_start_transaction(root, 12);
9393         if (IS_ERR(trans)) {
9394                 ret = PTR_ERR(trans);
9395                 goto out_notrans;
9396         }
9397
9398         /*
9399          * We need to find a free sequence number both in the source and
9400          * in the destination directory for the exchange.
9401          */
9402         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &old_idx);
9403         if (ret)
9404                 goto out_fail;
9405         ret = btrfs_set_inode_index(BTRFS_I(old_dir), &new_idx);
9406         if (ret)
9407                 goto out_fail;
9408
9409         BTRFS_I(old_inode)->dir_index = 0ULL;
9410         BTRFS_I(new_inode)->dir_index = 0ULL;
9411
9412         /* Reference for the source. */
9413         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9414                 /* force full log commit if subvolume involved. */
9415                 btrfs_set_log_full_commit(fs_info, trans);
9416         } else {
9417                 btrfs_pin_log_trans(root);
9418                 root_log_pinned = true;
9419                 ret = btrfs_insert_inode_ref(trans, dest,
9420                                              new_dentry->d_name.name,
9421                                              new_dentry->d_name.len,
9422                                              old_ino,
9423                                              btrfs_ino(BTRFS_I(new_dir)),
9424                                              old_idx);
9425                 if (ret)
9426                         goto out_fail;
9427         }
9428
9429         /* And now for the dest. */
9430         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9431                 /* force full log commit if subvolume involved. */
9432                 btrfs_set_log_full_commit(fs_info, trans);
9433         } else {
9434                 btrfs_pin_log_trans(dest);
9435                 dest_log_pinned = true;
9436                 ret = btrfs_insert_inode_ref(trans, root,
9437                                              old_dentry->d_name.name,
9438                                              old_dentry->d_name.len,
9439                                              new_ino,
9440                                              btrfs_ino(BTRFS_I(old_dir)),
9441                                              new_idx);
9442                 if (ret)
9443                         goto out_fail;
9444         }
9445
9446         /* Update inode version and ctime/mtime. */
9447         inode_inc_iversion(old_dir);
9448         inode_inc_iversion(new_dir);
9449         inode_inc_iversion(old_inode);
9450         inode_inc_iversion(new_inode);
9451         old_dir->i_ctime = old_dir->i_mtime = ctime;
9452         new_dir->i_ctime = new_dir->i_mtime = ctime;
9453         old_inode->i_ctime = ctime;
9454         new_inode->i_ctime = ctime;
9455
9456         if (old_dentry->d_parent != new_dentry->d_parent) {
9457                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9458                                 BTRFS_I(old_inode), 1);
9459                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
9460                                 BTRFS_I(new_inode), 1);
9461         }
9462
9463         /* src is a subvolume */
9464         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9465                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9466                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9467                                           old_dentry->d_name.name,
9468                                           old_dentry->d_name.len);
9469         } else { /* src is an inode */
9470                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9471                                            BTRFS_I(old_dentry->d_inode),
9472                                            old_dentry->d_name.name,
9473                                            old_dentry->d_name.len);
9474                 if (!ret)
9475                         ret = btrfs_update_inode(trans, root, old_inode);
9476         }
9477         if (ret) {
9478                 btrfs_abort_transaction(trans, ret);
9479                 goto out_fail;
9480         }
9481
9482         /* dest is a subvolume */
9483         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9484                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9485                 ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9486                                           new_dentry->d_name.name,
9487                                           new_dentry->d_name.len);
9488         } else { /* dest is an inode */
9489                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9490                                            BTRFS_I(new_dentry->d_inode),
9491                                            new_dentry->d_name.name,
9492                                            new_dentry->d_name.len);
9493                 if (!ret)
9494                         ret = btrfs_update_inode(trans, dest, new_inode);
9495         }
9496         if (ret) {
9497                 btrfs_abort_transaction(trans, ret);
9498                 goto out_fail;
9499         }
9500
9501         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9502                              new_dentry->d_name.name,
9503                              new_dentry->d_name.len, 0, old_idx);
9504         if (ret) {
9505                 btrfs_abort_transaction(trans, ret);
9506                 goto out_fail;
9507         }
9508
9509         ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
9510                              old_dentry->d_name.name,
9511                              old_dentry->d_name.len, 0, new_idx);
9512         if (ret) {
9513                 btrfs_abort_transaction(trans, ret);
9514                 goto out_fail;
9515         }
9516
9517         if (old_inode->i_nlink == 1)
9518                 BTRFS_I(old_inode)->dir_index = old_idx;
9519         if (new_inode->i_nlink == 1)
9520                 BTRFS_I(new_inode)->dir_index = new_idx;
9521
9522         if (root_log_pinned) {
9523                 parent = new_dentry->d_parent;
9524                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9525                                          BTRFS_I(old_dir), parent,
9526                                          false, &ctx_root);
9527                 if (ret == BTRFS_NEED_LOG_SYNC)
9528                         sync_log_root = true;
9529                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9530                         commit_transaction = true;
9531                 ret = 0;
9532                 btrfs_end_log_trans(root);
9533                 root_log_pinned = false;
9534         }
9535         if (dest_log_pinned) {
9536                 if (!commit_transaction) {
9537                         parent = old_dentry->d_parent;
9538                         ret = btrfs_log_new_name(trans, BTRFS_I(new_inode),
9539                                                  BTRFS_I(new_dir), parent,
9540                                                  false, &ctx_dest);
9541                         if (ret == BTRFS_NEED_LOG_SYNC)
9542                                 sync_log_dest = true;
9543                         else if (ret == BTRFS_NEED_TRANS_COMMIT)
9544                                 commit_transaction = true;
9545                         ret = 0;
9546                 }
9547                 btrfs_end_log_trans(dest);
9548                 dest_log_pinned = false;
9549         }
9550 out_fail:
9551         /*
9552          * If we have pinned a log and an error happened, we unpin tasks
9553          * trying to sync the log and force them to fallback to a transaction
9554          * commit if the log currently contains any of the inodes involved in
9555          * this rename operation (to ensure we do not persist a log with an
9556          * inconsistent state for any of these inodes or leading to any
9557          * inconsistencies when replayed). If the transaction was aborted, the
9558          * abortion reason is propagated to userspace when attempting to commit
9559          * the transaction. If the log does not contain any of these inodes, we
9560          * allow the tasks to sync it.
9561          */
9562         if (ret && (root_log_pinned || dest_log_pinned)) {
9563                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9564                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9565                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9566                     (new_inode &&
9567                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9568                         btrfs_set_log_full_commit(fs_info, trans);
9569
9570                 if (root_log_pinned) {
9571                         btrfs_end_log_trans(root);
9572                         root_log_pinned = false;
9573                 }
9574                 if (dest_log_pinned) {
9575                         btrfs_end_log_trans(dest);
9576                         dest_log_pinned = false;
9577                 }
9578         }
9579         if (!ret && sync_log_root && !commit_transaction) {
9580                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root,
9581                                      &ctx_root);
9582                 if (ret)
9583                         commit_transaction = true;
9584         }
9585         if (!ret && sync_log_dest && !commit_transaction) {
9586                 ret = btrfs_sync_log(trans, BTRFS_I(new_inode)->root,
9587                                      &ctx_dest);
9588                 if (ret)
9589                         commit_transaction = true;
9590         }
9591         if (commit_transaction) {
9592                 ret = btrfs_commit_transaction(trans);
9593         } else {
9594                 int ret2;
9595
9596                 ret2 = btrfs_end_transaction(trans);
9597                 ret = ret ? ret : ret2;
9598         }
9599 out_notrans:
9600         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9601                 up_read(&fs_info->subvol_sem);
9602         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9603                 up_read(&fs_info->subvol_sem);
9604
9605         return ret;
9606 }
9607
9608 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9609                                      struct btrfs_root *root,
9610                                      struct inode *dir,
9611                                      struct dentry *dentry)
9612 {
9613         int ret;
9614         struct inode *inode;
9615         u64 objectid;
9616         u64 index;
9617
9618         ret = btrfs_find_free_ino(root, &objectid);
9619         if (ret)
9620                 return ret;
9621
9622         inode = btrfs_new_inode(trans, root, dir,
9623                                 dentry->d_name.name,
9624                                 dentry->d_name.len,
9625                                 btrfs_ino(BTRFS_I(dir)),
9626                                 objectid,
9627                                 S_IFCHR | WHITEOUT_MODE,
9628                                 &index);
9629
9630         if (IS_ERR(inode)) {
9631                 ret = PTR_ERR(inode);
9632                 return ret;
9633         }
9634
9635         inode->i_op = &btrfs_special_inode_operations;
9636         init_special_inode(inode, inode->i_mode,
9637                 WHITEOUT_DEV);
9638
9639         ret = btrfs_init_inode_security(trans, inode, dir,
9640                                 &dentry->d_name);
9641         if (ret)
9642                 goto out;
9643
9644         ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9645                                 BTRFS_I(inode), 0, index);
9646         if (ret)
9647                 goto out;
9648
9649         ret = btrfs_update_inode(trans, root, inode);
9650 out:
9651         unlock_new_inode(inode);
9652         if (ret)
9653                 inode_dec_link_count(inode);
9654         iput(inode);
9655
9656         return ret;
9657 }
9658
9659 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9660                            struct inode *new_dir, struct dentry *new_dentry,
9661                            unsigned int flags)
9662 {
9663         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9664         struct btrfs_trans_handle *trans;
9665         unsigned int trans_num_items;
9666         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9667         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9668         struct inode *new_inode = d_inode(new_dentry);
9669         struct inode *old_inode = d_inode(old_dentry);
9670         u64 index = 0;
9671         u64 root_objectid;
9672         int ret;
9673         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9674         bool log_pinned = false;
9675         struct btrfs_log_ctx ctx;
9676         bool sync_log = false;
9677         bool commit_transaction = false;
9678
9679         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9680                 return -EPERM;
9681
9682         /* we only allow rename subvolume link between subvolumes */
9683         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9684                 return -EXDEV;
9685
9686         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9687             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9688                 return -ENOTEMPTY;
9689
9690         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9691             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9692                 return -ENOTEMPTY;
9693
9694
9695         /* check for collisions, even if the  name isn't there */
9696         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9697                              new_dentry->d_name.name,
9698                              new_dentry->d_name.len);
9699
9700         if (ret) {
9701                 if (ret == -EEXIST) {
9702                         /* we shouldn't get
9703                          * eexist without a new_inode */
9704                         if (WARN_ON(!new_inode)) {
9705                                 return ret;
9706                         }
9707                 } else {
9708                         /* maybe -EOVERFLOW */
9709                         return ret;
9710                 }
9711         }
9712         ret = 0;
9713
9714         /*
9715          * we're using rename to replace one file with another.  Start IO on it
9716          * now so  we don't add too much work to the end of the transaction
9717          */
9718         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9719                 filemap_flush(old_inode->i_mapping);
9720
9721         /* close the racy window with snapshot create/destroy ioctl */
9722         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9723                 down_read(&fs_info->subvol_sem);
9724         /*
9725          * We want to reserve the absolute worst case amount of items.  So if
9726          * both inodes are subvols and we need to unlink them then that would
9727          * require 4 item modifications, but if they are both normal inodes it
9728          * would require 5 item modifications, so we'll assume they are normal
9729          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9730          * should cover the worst case number of items we'll modify.
9731          * If our rename has the whiteout flag, we need more 5 units for the
9732          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9733          * when selinux is enabled).
9734          */
9735         trans_num_items = 11;
9736         if (flags & RENAME_WHITEOUT)
9737                 trans_num_items += 5;
9738         trans = btrfs_start_transaction(root, trans_num_items);
9739         if (IS_ERR(trans)) {
9740                 ret = PTR_ERR(trans);
9741                 goto out_notrans;
9742         }
9743
9744         if (dest != root)
9745                 btrfs_record_root_in_trans(trans, dest);
9746
9747         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &index);
9748         if (ret)
9749                 goto out_fail;
9750
9751         BTRFS_I(old_inode)->dir_index = 0ULL;
9752         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9753                 /* force full log commit if subvolume involved. */
9754                 btrfs_set_log_full_commit(fs_info, trans);
9755         } else {
9756                 btrfs_pin_log_trans(root);
9757                 log_pinned = true;
9758                 ret = btrfs_insert_inode_ref(trans, dest,
9759                                              new_dentry->d_name.name,
9760                                              new_dentry->d_name.len,
9761                                              old_ino,
9762                                              btrfs_ino(BTRFS_I(new_dir)), index);
9763                 if (ret)
9764                         goto out_fail;
9765         }
9766
9767         inode_inc_iversion(old_dir);
9768         inode_inc_iversion(new_dir);
9769         inode_inc_iversion(old_inode);
9770         old_dir->i_ctime = old_dir->i_mtime =
9771         new_dir->i_ctime = new_dir->i_mtime =
9772         old_inode->i_ctime = current_time(old_dir);
9773
9774         if (old_dentry->d_parent != new_dentry->d_parent)
9775                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9776                                 BTRFS_I(old_inode), 1);
9777
9778         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9779                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9780                 ret = btrfs_unlink_subvol(trans, old_dir, root_objectid,
9781                                         old_dentry->d_name.name,
9782                                         old_dentry->d_name.len);
9783         } else {
9784                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9785                                         BTRFS_I(d_inode(old_dentry)),
9786                                         old_dentry->d_name.name,
9787                                         old_dentry->d_name.len);
9788                 if (!ret)
9789                         ret = btrfs_update_inode(trans, root, old_inode);
9790         }
9791         if (ret) {
9792                 btrfs_abort_transaction(trans, ret);
9793                 goto out_fail;
9794         }
9795
9796         if (new_inode) {
9797                 inode_inc_iversion(new_inode);
9798                 new_inode->i_ctime = current_time(new_inode);
9799                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9800                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9801                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9802                         ret = btrfs_unlink_subvol(trans, new_dir, root_objectid,
9803                                                 new_dentry->d_name.name,
9804                                                 new_dentry->d_name.len);
9805                         BUG_ON(new_inode->i_nlink == 0);
9806                 } else {
9807                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9808                                                  BTRFS_I(d_inode(new_dentry)),
9809                                                  new_dentry->d_name.name,
9810                                                  new_dentry->d_name.len);
9811                 }
9812                 if (!ret && new_inode->i_nlink == 0)
9813                         ret = btrfs_orphan_add(trans,
9814                                         BTRFS_I(d_inode(new_dentry)));
9815                 if (ret) {
9816                         btrfs_abort_transaction(trans, ret);
9817                         goto out_fail;
9818                 }
9819         }
9820
9821         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9822                              new_dentry->d_name.name,
9823                              new_dentry->d_name.len, 0, index);
9824         if (ret) {
9825                 btrfs_abort_transaction(trans, ret);
9826                 goto out_fail;
9827         }
9828
9829         if (old_inode->i_nlink == 1)
9830                 BTRFS_I(old_inode)->dir_index = index;
9831
9832         if (log_pinned) {
9833                 struct dentry *parent = new_dentry->d_parent;
9834
9835                 btrfs_init_log_ctx(&ctx, old_inode);
9836                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9837                                          BTRFS_I(old_dir), parent,
9838                                          false, &ctx);
9839                 if (ret == BTRFS_NEED_LOG_SYNC)
9840                         sync_log = true;
9841                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9842                         commit_transaction = true;
9843                 ret = 0;
9844                 btrfs_end_log_trans(root);
9845                 log_pinned = false;
9846         }
9847
9848         if (flags & RENAME_WHITEOUT) {
9849                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9850                                                 old_dentry);
9851
9852                 if (ret) {
9853                         btrfs_abort_transaction(trans, ret);
9854                         goto out_fail;
9855                 }
9856         }
9857 out_fail:
9858         /*
9859          * If we have pinned the log and an error happened, we unpin tasks
9860          * trying to sync the log and force them to fallback to a transaction
9861          * commit if the log currently contains any of the inodes involved in
9862          * this rename operation (to ensure we do not persist a log with an
9863          * inconsistent state for any of these inodes or leading to any
9864          * inconsistencies when replayed). If the transaction was aborted, the
9865          * abortion reason is propagated to userspace when attempting to commit
9866          * the transaction. If the log does not contain any of these inodes, we
9867          * allow the tasks to sync it.
9868          */
9869         if (ret && log_pinned) {
9870                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9871                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9872                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9873                     (new_inode &&
9874                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9875                         btrfs_set_log_full_commit(fs_info, trans);
9876
9877                 btrfs_end_log_trans(root);
9878                 log_pinned = false;
9879         }
9880         if (!ret && sync_log) {
9881                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx);
9882                 if (ret)
9883                         commit_transaction = true;
9884         }
9885         if (commit_transaction) {
9886                 ret = btrfs_commit_transaction(trans);
9887         } else {
9888                 int ret2;
9889
9890                 ret2 = btrfs_end_transaction(trans);
9891                 ret = ret ? ret : ret2;
9892         }
9893 out_notrans:
9894         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9895                 up_read(&fs_info->subvol_sem);
9896
9897         return ret;
9898 }
9899
9900 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9901                          struct inode *new_dir, struct dentry *new_dentry,
9902                          unsigned int flags)
9903 {
9904         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9905                 return -EINVAL;
9906
9907         if (flags & RENAME_EXCHANGE)
9908                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9909                                           new_dentry);
9910
9911         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9912 }
9913
9914 struct btrfs_delalloc_work {
9915         struct inode *inode;
9916         struct completion completion;
9917         struct list_head list;
9918         struct btrfs_work work;
9919 };
9920
9921 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9922 {
9923         struct btrfs_delalloc_work *delalloc_work;
9924         struct inode *inode;
9925
9926         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9927                                      work);
9928         inode = delalloc_work->inode;
9929         filemap_flush(inode->i_mapping);
9930         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9931                                 &BTRFS_I(inode)->runtime_flags))
9932                 filemap_flush(inode->i_mapping);
9933
9934         iput(inode);
9935         complete(&delalloc_work->completion);
9936 }
9937
9938 static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode)
9939 {
9940         struct btrfs_delalloc_work *work;
9941
9942         work = kmalloc(sizeof(*work), GFP_NOFS);
9943         if (!work)
9944                 return NULL;
9945
9946         init_completion(&work->completion);
9947         INIT_LIST_HEAD(&work->list);
9948         work->inode = inode;
9949         WARN_ON_ONCE(!inode);
9950         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9951                         btrfs_run_delalloc_work, NULL, NULL);
9952
9953         return work;
9954 }
9955
9956 /*
9957  * some fairly slow code that needs optimization. This walks the list
9958  * of all the inodes with pending delalloc and forces them to disk.
9959  */
9960 static int start_delalloc_inodes(struct btrfs_root *root, int nr)
9961 {
9962         struct btrfs_inode *binode;
9963         struct inode *inode;
9964         struct btrfs_delalloc_work *work, *next;
9965         struct list_head works;
9966         struct list_head splice;
9967         int ret = 0;
9968
9969         INIT_LIST_HEAD(&works);
9970         INIT_LIST_HEAD(&splice);
9971
9972         mutex_lock(&root->delalloc_mutex);
9973         spin_lock(&root->delalloc_lock);
9974         list_splice_init(&root->delalloc_inodes, &splice);
9975         while (!list_empty(&splice)) {
9976                 binode = list_entry(splice.next, struct btrfs_inode,
9977                                     delalloc_inodes);
9978
9979                 list_move_tail(&binode->delalloc_inodes,
9980                                &root->delalloc_inodes);
9981                 inode = igrab(&binode->vfs_inode);
9982                 if (!inode) {
9983                         cond_resched_lock(&root->delalloc_lock);
9984                         continue;
9985                 }
9986                 spin_unlock(&root->delalloc_lock);
9987
9988                 work = btrfs_alloc_delalloc_work(inode);
9989                 if (!work) {
9990                         iput(inode);
9991                         ret = -ENOMEM;
9992                         goto out;
9993                 }
9994                 list_add_tail(&work->list, &works);
9995                 btrfs_queue_work(root->fs_info->flush_workers,
9996                                  &work->work);
9997                 ret++;
9998                 if (nr != -1 && ret >= nr)
9999                         goto out;
10000                 cond_resched();
10001                 spin_lock(&root->delalloc_lock);
10002         }
10003         spin_unlock(&root->delalloc_lock);
10004
10005 out:
10006         list_for_each_entry_safe(work, next, &works, list) {
10007                 list_del_init(&work->list);
10008                 wait_for_completion(&work->completion);
10009                 kfree(work);
10010         }
10011
10012         if (!list_empty(&splice)) {
10013                 spin_lock(&root->delalloc_lock);
10014                 list_splice_tail(&splice, &root->delalloc_inodes);
10015                 spin_unlock(&root->delalloc_lock);
10016         }
10017         mutex_unlock(&root->delalloc_mutex);
10018         return ret;
10019 }
10020
10021 int btrfs_start_delalloc_inodes(struct btrfs_root *root)
10022 {
10023         struct btrfs_fs_info *fs_info = root->fs_info;
10024         int ret;
10025
10026         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10027                 return -EROFS;
10028
10029         ret = start_delalloc_inodes(root, -1);
10030         if (ret > 0)
10031                 ret = 0;
10032         return ret;
10033 }
10034
10035 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int nr)
10036 {
10037         struct btrfs_root *root;
10038         struct list_head splice;
10039         int ret;
10040
10041         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10042                 return -EROFS;
10043
10044         INIT_LIST_HEAD(&splice);
10045
10046         mutex_lock(&fs_info->delalloc_root_mutex);
10047         spin_lock(&fs_info->delalloc_root_lock);
10048         list_splice_init(&fs_info->delalloc_roots, &splice);
10049         while (!list_empty(&splice) && nr) {
10050                 root = list_first_entry(&splice, struct btrfs_root,
10051                                         delalloc_root);
10052                 root = btrfs_grab_fs_root(root);
10053                 BUG_ON(!root);
10054                 list_move_tail(&root->delalloc_root,
10055                                &fs_info->delalloc_roots);
10056                 spin_unlock(&fs_info->delalloc_root_lock);
10057
10058                 ret = start_delalloc_inodes(root, nr);
10059                 btrfs_put_fs_root(root);
10060                 if (ret < 0)
10061                         goto out;
10062
10063                 if (nr != -1) {
10064                         nr -= ret;
10065                         WARN_ON(nr < 0);
10066                 }
10067                 spin_lock(&fs_info->delalloc_root_lock);
10068         }
10069         spin_unlock(&fs_info->delalloc_root_lock);
10070
10071         ret = 0;
10072 out:
10073         if (!list_empty(&splice)) {
10074                 spin_lock(&fs_info->delalloc_root_lock);
10075                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10076                 spin_unlock(&fs_info->delalloc_root_lock);
10077         }
10078         mutex_unlock(&fs_info->delalloc_root_mutex);
10079         return ret;
10080 }
10081
10082 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10083                          const char *symname)
10084 {
10085         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10086         struct btrfs_trans_handle *trans;
10087         struct btrfs_root *root = BTRFS_I(dir)->root;
10088         struct btrfs_path *path;
10089         struct btrfs_key key;
10090         struct inode *inode = NULL;
10091         int err;
10092         u64 objectid;
10093         u64 index = 0;
10094         int name_len;
10095         int datasize;
10096         unsigned long ptr;
10097         struct btrfs_file_extent_item *ei;
10098         struct extent_buffer *leaf;
10099
10100         name_len = strlen(symname);
10101         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
10102                 return -ENAMETOOLONG;
10103
10104         /*
10105          * 2 items for inode item and ref
10106          * 2 items for dir items
10107          * 1 item for updating parent inode item
10108          * 1 item for the inline extent item
10109          * 1 item for xattr if selinux is on
10110          */
10111         trans = btrfs_start_transaction(root, 7);
10112         if (IS_ERR(trans))
10113                 return PTR_ERR(trans);
10114
10115         err = btrfs_find_free_ino(root, &objectid);
10116         if (err)
10117                 goto out_unlock;
10118
10119         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10120                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
10121                                 objectid, S_IFLNK|S_IRWXUGO, &index);
10122         if (IS_ERR(inode)) {
10123                 err = PTR_ERR(inode);
10124                 inode = NULL;
10125                 goto out_unlock;
10126         }
10127
10128         /*
10129         * If the active LSM wants to access the inode during
10130         * d_instantiate it needs these. Smack checks to see
10131         * if the filesystem supports xattrs by looking at the
10132         * ops vector.
10133         */
10134         inode->i_fop = &btrfs_file_operations;
10135         inode->i_op = &btrfs_file_inode_operations;
10136         inode->i_mapping->a_ops = &btrfs_aops;
10137         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10138
10139         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10140         if (err)
10141                 goto out_unlock;
10142
10143         path = btrfs_alloc_path();
10144         if (!path) {
10145                 err = -ENOMEM;
10146                 goto out_unlock;
10147         }
10148         key.objectid = btrfs_ino(BTRFS_I(inode));
10149         key.offset = 0;
10150         key.type = BTRFS_EXTENT_DATA_KEY;
10151         datasize = btrfs_file_extent_calc_inline_size(name_len);
10152         err = btrfs_insert_empty_item(trans, root, path, &key,
10153                                       datasize);
10154         if (err) {
10155                 btrfs_free_path(path);
10156                 goto out_unlock;
10157         }
10158         leaf = path->nodes[0];
10159         ei = btrfs_item_ptr(leaf, path->slots[0],
10160                             struct btrfs_file_extent_item);
10161         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10162         btrfs_set_file_extent_type(leaf, ei,
10163                                    BTRFS_FILE_EXTENT_INLINE);
10164         btrfs_set_file_extent_encryption(leaf, ei, 0);
10165         btrfs_set_file_extent_compression(leaf, ei, 0);
10166         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10167         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10168
10169         ptr = btrfs_file_extent_inline_start(ei);
10170         write_extent_buffer(leaf, symname, ptr, name_len);
10171         btrfs_mark_buffer_dirty(leaf);
10172         btrfs_free_path(path);
10173
10174         inode->i_op = &btrfs_symlink_inode_operations;
10175         inode_nohighmem(inode);
10176         inode->i_mapping->a_ops = &btrfs_aops;
10177         inode_set_bytes(inode, name_len);
10178         btrfs_i_size_write(BTRFS_I(inode), name_len);
10179         err = btrfs_update_inode(trans, root, inode);
10180         /*
10181          * Last step, add directory indexes for our symlink inode. This is the
10182          * last step to avoid extra cleanup of these indexes if an error happens
10183          * elsewhere above.
10184          */
10185         if (!err)
10186                 err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
10187                                 BTRFS_I(inode), 0, index);
10188         if (err)
10189                 goto out_unlock;
10190
10191         d_instantiate_new(dentry, inode);
10192
10193 out_unlock:
10194         btrfs_end_transaction(trans);
10195         if (err && inode) {
10196                 inode_dec_link_count(inode);
10197                 discard_new_inode(inode);
10198         }
10199         btrfs_btree_balance_dirty(fs_info);
10200         return err;
10201 }
10202
10203 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10204                                        u64 start, u64 num_bytes, u64 min_size,
10205                                        loff_t actual_len, u64 *alloc_hint,
10206                                        struct btrfs_trans_handle *trans)
10207 {
10208         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
10209         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10210         struct extent_map *em;
10211         struct btrfs_root *root = BTRFS_I(inode)->root;
10212         struct btrfs_key ins;
10213         u64 cur_offset = start;
10214         u64 i_size;
10215         u64 cur_bytes;
10216         u64 last_alloc = (u64)-1;
10217         int ret = 0;
10218         bool own_trans = true;
10219         u64 end = start + num_bytes - 1;
10220
10221         if (trans)
10222                 own_trans = false;
10223         while (num_bytes > 0) {
10224                 if (own_trans) {
10225                         trans = btrfs_start_transaction(root, 3);
10226                         if (IS_ERR(trans)) {
10227                                 ret = PTR_ERR(trans);
10228                                 break;
10229                         }
10230                 }
10231
10232                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10233                 cur_bytes = max(cur_bytes, min_size);
10234                 /*
10235                  * If we are severely fragmented we could end up with really
10236                  * small allocations, so if the allocator is returning small
10237                  * chunks lets make its job easier by only searching for those
10238                  * sized chunks.
10239                  */
10240                 cur_bytes = min(cur_bytes, last_alloc);
10241                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
10242                                 min_size, 0, *alloc_hint, &ins, 1, 0);
10243                 if (ret) {
10244                         if (own_trans)
10245                                 btrfs_end_transaction(trans);
10246                         break;
10247                 }
10248                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
10249
10250                 last_alloc = ins.offset;
10251                 ret = insert_reserved_file_extent(trans, inode,
10252                                                   cur_offset, ins.objectid,
10253                                                   ins.offset, ins.offset,
10254                                                   ins.offset, 0, 0, 0,
10255                                                   BTRFS_FILE_EXTENT_PREALLOC);
10256                 if (ret) {
10257                         btrfs_free_reserved_extent(fs_info, ins.objectid,
10258                                                    ins.offset, 0);
10259                         btrfs_abort_transaction(trans, ret);
10260                         if (own_trans)
10261                                 btrfs_end_transaction(trans);
10262                         break;
10263                 }
10264
10265                 btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10266                                         cur_offset + ins.offset -1, 0);
10267
10268                 em = alloc_extent_map();
10269                 if (!em) {
10270                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10271                                 &BTRFS_I(inode)->runtime_flags);
10272                         goto next;
10273                 }
10274
10275                 em->start = cur_offset;
10276                 em->orig_start = cur_offset;
10277                 em->len = ins.offset;
10278                 em->block_start = ins.objectid;
10279                 em->block_len = ins.offset;
10280                 em->orig_block_len = ins.offset;
10281                 em->ram_bytes = ins.offset;
10282                 em->bdev = fs_info->fs_devices->latest_bdev;
10283                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10284                 em->generation = trans->transid;
10285
10286                 while (1) {
10287                         write_lock(&em_tree->lock);
10288                         ret = add_extent_mapping(em_tree, em, 1);
10289                         write_unlock(&em_tree->lock);
10290                         if (ret != -EEXIST)
10291                                 break;
10292                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
10293                                                 cur_offset + ins.offset - 1,
10294                                                 0);
10295                 }
10296                 free_extent_map(em);
10297 next:
10298                 num_bytes -= ins.offset;
10299                 cur_offset += ins.offset;
10300                 *alloc_hint = ins.objectid + ins.offset;
10301
10302                 inode_inc_iversion(inode);
10303                 inode->i_ctime = current_time(inode);
10304                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10305                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10306                     (actual_len > inode->i_size) &&
10307                     (cur_offset > inode->i_size)) {
10308                         if (cur_offset > actual_len)
10309                                 i_size = actual_len;
10310                         else
10311                                 i_size = cur_offset;
10312                         i_size_write(inode, i_size);
10313                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10314                 }
10315
10316                 ret = btrfs_update_inode(trans, root, inode);
10317
10318                 if (ret) {
10319                         btrfs_abort_transaction(trans, ret);
10320                         if (own_trans)
10321                                 btrfs_end_transaction(trans);
10322                         break;
10323                 }
10324
10325                 if (own_trans)
10326                         btrfs_end_transaction(trans);
10327         }
10328         if (cur_offset < end)
10329                 btrfs_free_reserved_data_space(inode, NULL, cur_offset,
10330                         end - cur_offset + 1);
10331         return ret;
10332 }
10333
10334 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10335                               u64 start, u64 num_bytes, u64 min_size,
10336                               loff_t actual_len, u64 *alloc_hint)
10337 {
10338         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10339                                            min_size, actual_len, alloc_hint,
10340                                            NULL);
10341 }
10342
10343 int btrfs_prealloc_file_range_trans(struct inode *inode,
10344                                     struct btrfs_trans_handle *trans, int mode,
10345                                     u64 start, u64 num_bytes, u64 min_size,
10346                                     loff_t actual_len, u64 *alloc_hint)
10347 {
10348         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10349                                            min_size, actual_len, alloc_hint, trans);
10350 }
10351
10352 static int btrfs_set_page_dirty(struct page *page)
10353 {
10354         return __set_page_dirty_nobuffers(page);
10355 }
10356
10357 static int btrfs_permission(struct inode *inode, int mask)
10358 {
10359         struct btrfs_root *root = BTRFS_I(inode)->root;
10360         umode_t mode = inode->i_mode;
10361
10362         if (mask & MAY_WRITE &&
10363             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10364                 if (btrfs_root_readonly(root))
10365                         return -EROFS;
10366                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10367                         return -EACCES;
10368         }
10369         return generic_permission(inode, mask);
10370 }
10371
10372 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10373 {
10374         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
10375         struct btrfs_trans_handle *trans;
10376         struct btrfs_root *root = BTRFS_I(dir)->root;
10377         struct inode *inode = NULL;
10378         u64 objectid;
10379         u64 index;
10380         int ret = 0;
10381
10382         /*
10383          * 5 units required for adding orphan entry
10384          */
10385         trans = btrfs_start_transaction(root, 5);
10386         if (IS_ERR(trans))
10387                 return PTR_ERR(trans);
10388
10389         ret = btrfs_find_free_ino(root, &objectid);
10390         if (ret)
10391                 goto out;
10392
10393         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10394                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
10395         if (IS_ERR(inode)) {
10396                 ret = PTR_ERR(inode);
10397                 inode = NULL;
10398                 goto out;
10399         }
10400
10401         inode->i_fop = &btrfs_file_operations;
10402         inode->i_op = &btrfs_file_inode_operations;
10403
10404         inode->i_mapping->a_ops = &btrfs_aops;
10405         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10406
10407         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10408         if (ret)
10409                 goto out;
10410
10411         ret = btrfs_update_inode(trans, root, inode);
10412         if (ret)
10413                 goto out;
10414         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10415         if (ret)
10416                 goto out;
10417
10418         /*
10419          * We set number of links to 0 in btrfs_new_inode(), and here we set
10420          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10421          * through:
10422          *
10423          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10424          */
10425         set_nlink(inode, 1);
10426         d_tmpfile(dentry, inode);
10427         unlock_new_inode(inode);
10428         mark_inode_dirty(inode);
10429 out:
10430         btrfs_end_transaction(trans);
10431         if (ret && inode)
10432                 discard_new_inode(inode);
10433         btrfs_btree_balance_dirty(fs_info);
10434         return ret;
10435 }
10436
10437 __attribute__((const))
10438 static int btrfs_readpage_io_failed_hook(struct page *page, int failed_mirror)
10439 {
10440         return -EAGAIN;
10441 }
10442
10443 static void btrfs_check_extent_io_range(void *private_data, const char *caller,
10444                                         u64 start, u64 end)
10445 {
10446         struct inode *inode = private_data;
10447         u64 isize;
10448
10449         isize = i_size_read(inode);
10450         if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
10451                 btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
10452                     "%s: ino %llu isize %llu odd range [%llu,%llu]",
10453                         caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
10454         }
10455 }
10456
10457 void btrfs_set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
10458 {
10459         struct inode *inode = tree->private_data;
10460         unsigned long index = start >> PAGE_SHIFT;
10461         unsigned long end_index = end >> PAGE_SHIFT;
10462         struct page *page;
10463
10464         while (index <= end_index) {
10465                 page = find_get_page(inode->i_mapping, index);
10466                 ASSERT(page); /* Pages should be in the extent_io_tree */
10467                 set_page_writeback(page);
10468                 put_page(page);
10469                 index++;
10470         }
10471 }
10472
10473 static const struct inode_operations btrfs_dir_inode_operations = {
10474         .getattr        = btrfs_getattr,
10475         .lookup         = btrfs_lookup,
10476         .create         = btrfs_create,
10477         .unlink         = btrfs_unlink,
10478         .link           = btrfs_link,
10479         .mkdir          = btrfs_mkdir,
10480         .rmdir          = btrfs_rmdir,
10481         .rename         = btrfs_rename2,
10482         .symlink        = btrfs_symlink,
10483         .setattr        = btrfs_setattr,
10484         .mknod          = btrfs_mknod,
10485         .listxattr      = btrfs_listxattr,
10486         .permission     = btrfs_permission,
10487         .get_acl        = btrfs_get_acl,
10488         .set_acl        = btrfs_set_acl,
10489         .update_time    = btrfs_update_time,
10490         .tmpfile        = btrfs_tmpfile,
10491 };
10492 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10493         .lookup         = btrfs_lookup,
10494         .permission     = btrfs_permission,
10495         .update_time    = btrfs_update_time,
10496 };
10497
10498 static const struct file_operations btrfs_dir_file_operations = {
10499         .llseek         = generic_file_llseek,
10500         .read           = generic_read_dir,
10501         .iterate_shared = btrfs_real_readdir,
10502         .open           = btrfs_opendir,
10503         .unlocked_ioctl = btrfs_ioctl,
10504 #ifdef CONFIG_COMPAT
10505         .compat_ioctl   = btrfs_compat_ioctl,
10506 #endif
10507         .release        = btrfs_release_file,
10508         .fsync          = btrfs_sync_file,
10509 };
10510
10511 static const struct extent_io_ops btrfs_extent_io_ops = {
10512         /* mandatory callbacks */
10513         .submit_bio_hook = btrfs_submit_bio_hook,
10514         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10515         .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
10516
10517         /* optional callbacks */
10518         .fill_delalloc = run_delalloc_range,
10519         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10520         .writepage_start_hook = btrfs_writepage_start_hook,
10521         .set_bit_hook = btrfs_set_bit_hook,
10522         .clear_bit_hook = btrfs_clear_bit_hook,
10523         .merge_extent_hook = btrfs_merge_extent_hook,
10524         .split_extent_hook = btrfs_split_extent_hook,
10525         .check_extent_io_range = btrfs_check_extent_io_range,
10526 };
10527
10528 /*
10529  * btrfs doesn't support the bmap operation because swapfiles
10530  * use bmap to make a mapping of extents in the file.  They assume
10531  * these extents won't change over the life of the file and they
10532  * use the bmap result to do IO directly to the drive.
10533  *
10534  * the btrfs bmap call would return logical addresses that aren't
10535  * suitable for IO and they also will change frequently as COW
10536  * operations happen.  So, swapfile + btrfs == corruption.
10537  *
10538  * For now we're avoiding this by dropping bmap.
10539  */
10540 static const struct address_space_operations btrfs_aops = {
10541         .readpage       = btrfs_readpage,
10542         .writepage      = btrfs_writepage,
10543         .writepages     = btrfs_writepages,
10544         .readpages      = btrfs_readpages,
10545         .direct_IO      = btrfs_direct_IO,
10546         .invalidatepage = btrfs_invalidatepage,
10547         .releasepage    = btrfs_releasepage,
10548         .set_page_dirty = btrfs_set_page_dirty,
10549         .error_remove_page = generic_error_remove_page,
10550 };
10551
10552 static const struct inode_operations btrfs_file_inode_operations = {
10553         .getattr        = btrfs_getattr,
10554         .setattr        = btrfs_setattr,
10555         .listxattr      = btrfs_listxattr,
10556         .permission     = btrfs_permission,
10557         .fiemap         = btrfs_fiemap,
10558         .get_acl        = btrfs_get_acl,
10559         .set_acl        = btrfs_set_acl,
10560         .update_time    = btrfs_update_time,
10561 };
10562 static const struct inode_operations btrfs_special_inode_operations = {
10563         .getattr        = btrfs_getattr,
10564         .setattr        = btrfs_setattr,
10565         .permission     = btrfs_permission,
10566         .listxattr      = btrfs_listxattr,
10567         .get_acl        = btrfs_get_acl,
10568         .set_acl        = btrfs_set_acl,
10569         .update_time    = btrfs_update_time,
10570 };
10571 static const struct inode_operations btrfs_symlink_inode_operations = {
10572         .get_link       = page_get_link,
10573         .getattr        = btrfs_getattr,
10574         .setattr        = btrfs_setattr,
10575         .permission     = btrfs_permission,
10576         .listxattr      = btrfs_listxattr,
10577         .update_time    = btrfs_update_time,
10578 };
10579
10580 const struct dentry_operations btrfs_dentry_operations = {
10581         .d_delete       = btrfs_dentry_delete,
10582 };