ceph: fix __choose_mds() for LSSNAP request

previous commit 5d37ca14 "ceph: send LSSNAP request to auth mds
of directory inode" is buggy. It makes __choose_mds() choose mds
base on hash of '.snap' dentry.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 84edfc60d87a..f23c820daaed 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -734,12 +734,13 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
                         inode = req->r_inode;
                         ihold(inode);
                 } else {
-                        /* req->r_dentry is non-null for LSSNAP request.
-                         * fall-thru */
-                        WARN_ON_ONCE(!req->r_dentry);
+                        /* req->r_dentry is non-null for LSSNAP request */
+                        rcu_read_lock();
+                        inode = get_nonsnap_parent(req->r_dentry);
+                        rcu_read_unlock();
+                        dout("__choose_mds using snapdir's parent %p\n", inode);
                 }
-        }
-        if (!inode && req->r_dentry) {
+        } else if (req->r_dentry) {
                 /* ignore race with rename; old or new d_parent is okay */
                 struct dentry *parent;
                 struct inode *dir;