From: Darrick J. Wong <djwong@kernel.org>
Date: Fri, 15 Aug 2025 16:25:58 +0000 (-0700)
Subject: libext2fs: relock CACHE_MTX after calling ->write_error
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;p=thirdparty%2Fe2fsprogs.git

libext2fs: relock CACHE_MTX after calling ->write_error

In the UNIX I/O manager, we drop CACHE_MTX before calling the
->write_error handler in case it decides to retry the failed write.
Therefore, we must retake the lock after it returns, to ensure
consistent lock state when flush_cached_blocks returns.

Cc: <linux-ext4@vger.kernel.org> # v1.46.6
Fixes: 0e0c7537eb5fdc ("libext2fs: unix_io: fix_potential error path deadlock in flush_cached_blocks()")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---

diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index 1af246da..cb408f51 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -734,6 +734,7 @@ retry:
 					retval2);
 				if (err_buf)
 					ext2fs_free_mem(&err_buf);
+				mutex_lock(data, CACHE_MTX);
 				goto retry;
 			} else
 				cache->write_err = 0;