From: Dominique Martinet <dominique.marti...@atmark-techno.com>
btrfs_file_read main 'aligned read' loop would limit the last read to
the aligned end even if the data is present in the extent: there is no
reason not to read the data that we know will be presented correctly.
If that somehow fails cur only advances up to the aligned_end anyway and
the file tail is read through the old code unchanged; this could be
required if e.g. the end data is inlined.
Signed-off-by: Dominique Martinet <dominique.marti...@atmark-techno.com>
---
fs/btrfs/inode.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3d6e39e6544d..efffec0f2e68 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -663,7 +663,8 @@ int btrfs_file_read(struct btrfs_root *root, u64 ino, u64
file_offset, u64 len,
struct btrfs_path path;
struct btrfs_key key;
u64 aligned_start = round_down(file_offset, fs_info->sectorsize);
- u64 aligned_end = round_down(file_offset + len, fs_info->sectorsize);
+ u64 end = file_offset + len;
+ u64 aligned_end = round_down(end, fs_info->sectorsize);
u64 next_offset;
u64 cur = aligned_start;
int ret = 0;
@@ -743,26 +744,26 @@ int btrfs_file_read(struct btrfs_root *root, u64 ino, u64
file_offset, u64 len,
extent_num_bytes = btrfs_file_extent_num_bytes(path.nodes[0],
fi);
ret = btrfs_read_extent_reg(&path, fi, cur,
- min(extent_num_bytes, aligned_end - cur),
+ min(extent_num_bytes, end - cur),
dest + cur - file_offset);
if (ret < 0)
goto out;
- cur += min(extent_num_bytes, aligned_end - cur);
+ cur += min(extent_num_bytes, end - cur);
}
/* Read the tailing unaligned part*/
- if (file_offset + len != aligned_end) {
+ if (file_offset + len != cur) {
btrfs_release_path(&path);
- ret = lookup_data_extent(root, &path, ino, aligned_end,
+ ret = lookup_data_extent(root, &path, ino, cur,
&next_offset);
/* <0 is error, >0 means no extent */
if (ret)
goto out;
fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
struct btrfs_file_extent_item);
- ret = read_and_truncate_page(&path, fi, aligned_end,
- file_offset + len - aligned_end,
- dest + aligned_end - file_offset);
+ ret = read_and_truncate_page(&path, fi, cur,
+ file_offset + len - cur,
+ dest + cur - file_offset);
}
out:
btrfs_release_path(&path);
--
2.39.2
