diff options
| author | Qu Wenruo <wqu@suse.com> | 2024-08-30 16:35:48 +0930 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2024-09-10 16:51:18 +0200 |
| commit | 77b0b98bb743f5d04d8f995ba1936e1143689d4a (patch) | |
| tree | 0aa22c2f50192c0378faf19640247b7fdb45ae03 /fs/btrfs | |
| parent | 0ae653fbec2b9fbc72c65a0c99528990bfb2136d (diff) | |
btrfs: subpage: fix the bitmap dump which can cause bitmap corruption
In commit 75258f20fb70 ("btrfs: subpage: dump extra subpage bitmaps for
debug") an internal macro GET_SUBPAGE_BITMAP() is introduced to grab the
bitmap of each attribute.
But that commit is using bitmap_cut() which will do the left shift of
the larger bitmap, causing incorrect values.
Thankfully this bitmap_cut() is only called for debug usage, and so far
it's not yet causing problem.
Fix it to use bitmap_read() to only grab the desired sub-bitmap.
Fixes: 75258f20fb70 ("btrfs: subpage: dump extra subpage bitmaps for debug")
CC: stable@vger.kernel.org # 6.6+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/subpage.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 631d96f1e905..f8795c3d2270 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -902,8 +902,14 @@ void btrfs_folio_end_all_writers(const struct btrfs_fs_info *fs_info, struct fol } #define GET_SUBPAGE_BITMAP(subpage, subpage_info, name, dst) \ - bitmap_cut(dst, subpage->bitmaps, 0, \ - subpage_info->name##_offset, subpage_info->bitmap_nr_bits) +{ \ + const int bitmap_nr_bits = subpage_info->bitmap_nr_bits; \ + \ + ASSERT(bitmap_nr_bits < BITS_PER_LONG); \ + *dst = bitmap_read(subpage->bitmaps, \ + subpage_info->name##_offset, \ + bitmap_nr_bits); \ +} void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len) |