ceph: defer stopping mdsc delayed_work

Flushing the dirty buffer may take a long time if the cluster is
overloaded or if there is network issue. So we should ping the
MDSs periodically to keep alive, else the MDS will blocklist
the kclient.

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/61843
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 66048a8..5fb367b 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4764,7 +4764,7 @@ static void delayed_work(struct work_struct *work)
 
        dout("mdsc delayed_work\n");
 
-       if (mdsc->stopping)
+       if (mdsc->stopping >= CEPH_MDSC_STOPPING_FLUSHED)
                return;
 
        mutex_lock(&mdsc->mutex);
@@ -4943,7 +4943,7 @@ void send_flush_mdlog(struct ceph_mds_session *s)
 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
 {
        dout("pre_umount\n");
-       mdsc->stopping = 1;
+       mdsc->stopping = CEPH_MDSC_STOPPING_BEGIN;
 
        ceph_mdsc_iterate_sessions(mdsc, send_flush_mdlog, true);
        ceph_mdsc_iterate_sessions(mdsc, lock_unlock_session, false);

diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 724307f..86d2965 100644 (file)
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -380,6 +380,11 @@ struct cap_wait {
        int                     want;
 };
 
+enum {
+       CEPH_MDSC_STOPPING_BEGIN = 1,
+       CEPH_MDSC_STOPPING_FLUSHED = 2,
+};
+
 /*
  * mds client state
  */

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 3fc48b4..a5f5201 100644 (file)
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -1374,6 +1374,16 @@ static void ceph_kill_sb(struct super_block *s)
        ceph_mdsc_pre_umount(fsc->mdsc);
        flush_fs_workqueues(fsc);
 
+       /*
+        * Though the kill_anon_super() will finally trigger the
+        * sync_filesystem() anyway, we still need to do it here
+        * and then bump the stage of shutdown to stop the work
+        * queue as earlier as possible.
+        */
+       sync_filesystem(s);
+
+       fsc->mdsc->stopping = CEPH_MDSC_STOPPING_FLUSHED;
+
        kill_anon_super(s);
 
        fsc->client->extra_mon_dispatch = NULL;