ceph: fix null pointer dereference in send_mds_reconnect()
sb->s_root can be null when umounting
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index fd5585b..0a2eb32 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2892,7 +2892,8 @@
spin_unlock(&session->s_cap_lock);
/* trim unused caps to reduce MDS's cache rejoin time */
- shrink_dcache_parent(mdsc->fsc->sb->s_root);
+ if (mdsc->fsc->sb->s_root)
+ shrink_dcache_parent(mdsc->fsc->sb->s_root);
ceph_con_close(&session->s_con);
ceph_con_open(&session->s_con,