[PATCH] ceph: trim unused inodes before reconnecting to recovering MDS

[Yan, Zheng]

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 <***@redhat.com>
---
fs/ceph/mds_client.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index bad07c0..f751fea 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);