diff options
| -rw-r--r-- | fs/btrfs/inode.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 78139efe41f..d8393ddc72a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -743,8 +743,22 @@ static noinline int cow_file_range(struct inode *inode, em = search_extent_mapping(&BTRFS_I(inode)->extent_tree, start, num_bytes); if (em) { - alloc_hint = em->block_start; - free_extent_map(em); + /* + * if block start isn't an actual block number then find the + * first block in this inode and use that as a hint. If that + * block is also bogus then just don't worry about it. + */ + if (em->block_start >= EXTENT_MAP_LAST_BYTE) { + free_extent_map(em); + em = search_extent_mapping(em_tree, 0, 0); + if (em && em->block_start < EXTENT_MAP_LAST_BYTE) + alloc_hint = em->block_start; + if (em) + free_extent_map(em); + } else { + alloc_hint = em->block_start; + free_extent_map(em); + } } read_unlock(&BTRFS_I(inode)->extent_tree.lock); btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0); |