ceph: trim unused inodes before reconnecting to recovering MDS

So the recovering MDS does not need to fetch these ununsed inodes during
cache rejoin. This may reduce MDS recovery time.

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 13 insertions, 10 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index bad07c09f91e..f751fea416e5 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2695,16 +2695,6 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
         session->s_state = CEPH_MDS_SESSION_RECONNECTING;
         session->s_seq = 0;
 
-        ceph_con_close(&session->s_con);
-        ceph_con_open(&session->s_con,
-                      CEPH_ENTITY_TYPE_MDS, mds,
-                      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
-
-        /* replay unsafe requests */
-        replay_unsafe_requests(mdsc, session);
-
-        down_read(&mdsc->snap_rwsem);
-
         dout("session %p state %s\n", session,
              session_state_name(session->s_state));
 
@@ -2723,6 +2713,19 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
         discard_cap_releases(mdsc, session);
         spin_unlock(&session->s_cap_lock);
 
+        /* trim unused caps to reduce MDS's cache rejoin time */
+        shrink_dcache_parent(mdsc->fsc->sb->s_root);
+
+        ceph_con_close(&session->s_con);
+        ceph_con_open(&session->s_con,
+                      CEPH_ENTITY_TYPE_MDS, mds,
+                      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
+
+        /* replay unsafe requests */
+        replay_unsafe_requests(mdsc, session);
+
+        down_read(&mdsc->snap_rwsem);
+
         /* traverse this session's caps */
         s_nr_caps = session->s_nr_caps;
         err = ceph_pagelist_encode_32(pagelist, s_nr_caps);