[PATCH 24/26] xfs: drop dquot flush lock when we can't find a buffer to flush

[Eduard Zateev <hackerowskiy@gmail.com>]

From: "Darrick J. Wong" <djwong@kernel.org>

LOLLM noticed that xfs_qm_flush_one fails to drop the dquot flush lock
if it can't grab the buffer associated with the dquot.  Since there's no
buffer, nobody else is going to drop the dqflock, so we need to do it
ourselves.

Cc: stable@vger.kernel.org # v6.13
Fixes: ca378189fdfa89 ("xfs: convert quotacheck to attach dquot buffers")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Assisted-by: LOLLM # finding obvious bugs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---
 fs/xfs/xfs_qm.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 99a82107b8e6..54d00d543b51 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1432,16 +1432,22 @@ xfs_qm_flush_one(
 
 	error = xfs_dquot_use_attached_buf(dqp, &bp);
 	if (error)
-		goto out_unlock;
+		goto out_dqflock;
 	if (!bp) {
 		error = -EFSCORRUPTED;
-		goto out_unlock;
+		goto out_dqflock;
 	}
 
 	error = xfs_qm_dqflush(dqp, bp);
 	if (!error)
 		xfs_buf_delwri_queue(bp, buffer_list);
 	xfs_buf_relse(bp);
+	mutex_unlock(&dqp->q_qlock);
+	xfs_qm_dqrele(dqp);
+	return error;
+
+out_dqflock:
+	xfs_dqfunlock(dqp);
 out_unlock:
 	mutex_unlock(&dqp->q_qlock);
 	xfs_qm_dqrele(dqp);
-- 
2.55.0