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 1af246d..cb408f5 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -734,6 +734,7 @@
retval2);
if (err_buf)
ext2fs_free_mem(&err_buf);
+ mutex_lock(data, CACHE_MTX);
goto retry;
} else
cache->write_err = 0;
