ceph: fix double unlock in handle_cap_export()

[ Upstream commit 4d8e28ff3106b093d98bfd2eceb9b430c70a8758 ]

If the ceph_mdsc_open_export_target_session() return fails, it will
do a "goto retry", but the session mutex has already been unlocked.
Re-lock the mutex in that case to ensure that we don't unlock it
twice.

Signed-off-by: Wu Bo <wubo40@huawei.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index efdf81ea3b5f8c617fa8132fb9dc63aa5dc10e9c..3d0497421e62bb8c06c491a33bf7a995d0182524 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3293,6 +3293,7 @@ static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
                WARN_ON(1);
                tsession = NULL;
                target = -1;
+               mutex_lock(&session->s_mutex);
        }
        goto retry;