diff options
Diffstat (limited to 'fs/btrfs/direct-io.c')
| -rw-r--r-- | fs/btrfs/direct-io.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/btrfs/direct-io.c b/fs/btrfs/direct-io.c index 8567af46e16f..a374ce7a1813 100644 --- a/fs/btrfs/direct-io.c +++ b/fs/btrfs/direct-io.c @@ -248,7 +248,8 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, len = min(len, em->len - (start - em->start)); block_start = extent_map_block_start(em) + (start - em->start); - if (can_nocow_extent(inode, start, &len, &file_extent, false) == 1) { + if (can_nocow_extent(BTRFS_I(inode), start, &len, &file_extent, + false) == 1) { bg = btrfs_inc_nocow_writers(fs_info, block_start); if (bg) can_nocow = true; @@ -855,6 +856,22 @@ relock: btrfs_inode_unlock(BTRFS_I(inode), ilock_flags); goto buffered; } + /* + * We can't control the folios being passed in, applications can write + * to them while a direct IO write is in progress. This means the + * content might change after we calculated the data checksum. + * Therefore we can end up storing a checksum that doesn't match the + * persisted data. + * + * To be extra safe and avoid false data checksum mismatch, if the + * inode requires data checksum, just fallback to buffered IO. + * For buffered IO we have full control of page cache and can ensure + * no one is modifying the content during writeback. + */ + if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { + btrfs_inode_unlock(BTRFS_I(inode), ilock_flags); + goto buffered; + } /* * The iov_iter can be mapped to the same file range we are writing to. |