From: Xiubo Li <xiubli@redhat.com>
Date: Tue, 25 Jul 2023 12:03:59 +0800
Subject: ceph: defer stopping mdsc delayed_work
Git-commit: e7e607bd00481745550389a29ecabe33e13d67cf
Patch-mainline: v6.5-rc5
References: bsc#1214392

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>
Acked-by: Luís Henriques <lhenriques@suse.de>

---
 fs/ceph/mds_client.c |    4 ++--
 fs/ceph/mds_client.h |    5 +++++
 fs/ceph/super.c      |   10 ++++++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4547,7 +4547,7 @@ static void delayed_work(struct work_str
 
 	dout("mdsc delayed_work\n");
 
-	if (mdsc->stopping)
+	if (mdsc->stopping >= CEPH_MDSC_STOPPING_FLUSHED)
 		return;
 
 	mutex_lock(&mdsc->mutex);
@@ -4713,7 +4713,7 @@ static void wait_requests(struct ceph_md
 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
 {
 	dout("pre_umount\n");
-	mdsc->stopping = 1;
+	mdsc->stopping = CEPH_MDSC_STOPPING_BEGIN;
 
 	lock_unlock_sessions(mdsc);
 	ceph_flush_dirty_caps(mdsc);
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -370,6 +370,11 @@ struct cap_wait {
 	int			want;
 };
 
+enum {
+       CEPH_MDSC_STOPPING_BEGIN = 1,
+       CEPH_MDSC_STOPPING_FLUSHED = 2,
+};
+
 /*
  * mds client state
  */
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -1227,6 +1227,16 @@ static void ceph_kill_sb(struct super_bl
 	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;