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Commit 91e4c459 authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Greg Kroah-Hartman
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nilfs2: prevent kernel bug at submit_bh_wbc() 

[ Upstream commit 269cdf353b5bdd15f1a079671b0f889113865f20 ]

Fix a bug where nilfs_get_block() returns a successful status when
searching and inserting the specified block both fail inconsistently.  If
this inconsistent behavior is not due to a previously fixed bug, then an
unexpected race is occurring, so return a temporary error -EAGAIN instead.

This prevents callers such as __block_write_begin_int() from requesting a
read into a buffer that is not mapped, which would cause the BUG_ON check
for the BH_Mapped flag in submit_bh_wbc() to fail.

Link: https://lkml.kernel.org/r/20240313105827.5296-3-konishi.ryusuke@gmail.com


Fixes: 1f5abe7e ("nilfs2: replace BUG_ON and BUG calls triggerable from ioctl")
Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5c8f85e9

fs/nilfs2/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ int nilfs_get_block(struct inode *inode, sector_t blkoff, 
					   "%s (ino=%lu): a race condition while inserting a data block at offset=%llu",

					   __func__, inode->i_ino,

					   (unsigned long long)blkoff);

				err = 0;

				err = -EAGAIN;

			}

			nilfs_transaction_abort(inode->i_sb);

			goto out;