btrfs: subpage: fix the bitmap dump which can cause bitmap corruption

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[ Upstream commit 77b0b98bb7 ]

In commit 75258f20fb ("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: 75258f20fb ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Qu Wenruo 2024-08-30 16:35:48 +09:30 • committed by Greg Kroah-Hartman

parent 459b724c3c

commit 0131bf19a1

1 changed files with 8 additions and 2 deletions

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fs/btrfs/subpage.c

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