From: Xiubo Li <xiubli@redhat.com>
Date: Thu, 26 May 2022 13:21:31 +0800
Subject: ceph: add session already open notify support
Git-commit: 300e42a2e79e2270a00dbf9e4ddd4b101dd75a03
Patch-mainline: v6.0-rc1
References: jsc#SES-1880

If the connection was accidently closed due to the socket issue or
something else the clients will try to open the opened sessions, the
MDSes will send the session open reply one more time if the clients
support the notify feature.

When the clients retry to open the sessions the s_seq will be 0 as
default, we need to update it anyway.

Link: https://tracker.ceph.com/issues/53911
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/mds_client.c | 25 ++++++++++++++++++++-----
 fs/ceph/mds_client.h |  5 ++++-
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index f6da80d110dc..9cfa7b775fdb 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3540,11 +3540,26 @@ static void handle_session(struct ceph_mds_session *session,
 	case CEPH_SESSION_OPEN:
 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
 			pr_info("mds%d reconnect success\n", session->s_mds);
-		session->s_state = CEPH_MDS_SESSION_OPEN;
-		session->s_features = features;
-		renewed_caps(mdsc, session, 0);
-		if (test_bit(CEPHFS_FEATURE_METRIC_COLLECT, &session->s_features))
-			metric_schedule_delayed(&mdsc->metric);
+
+		if (session->s_state == CEPH_MDS_SESSION_OPEN) {
+			pr_notice("mds%d is already opened\n", session->s_mds);
+		} else {
+			session->s_state = CEPH_MDS_SESSION_OPEN;
+			session->s_features = features;
+			renewed_caps(mdsc, session, 0);
+			if (test_bit(CEPHFS_FEATURE_METRIC_COLLECT,
+				     &session->s_features))
+				metric_schedule_delayed(&mdsc->metric);
+		}
+
+		/*
+		 * The connection maybe broken and the session in client
+		 * side has been reinitialized, need to update the seq
+		 * anyway.
+		 */
+		if (!session->s_seq && seq)
+			session->s_seq = seq;
+
 		wake = 1;
 		if (mdsc->stopping)
 			__close_session(mdsc, session);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index d8ec2ac93da3..256e3eada6c1 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -29,8 +29,10 @@ enum ceph_feature_type {
 	CEPHFS_FEATURE_MULTI_RECONNECT,
 	CEPHFS_FEATURE_DELEG_INO,
 	CEPHFS_FEATURE_METRIC_COLLECT,
+	CEPHFS_FEATURE_ALTERNATE_NAME,
+	CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
 
-	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_METRIC_COLLECT,
+	CEPHFS_FEATURE_MAX = CEPHFS_FEATURE_NOTIFY_SESSION_STATE,
 };
 
 #define CEPHFS_FEATURES_CLIENT_SUPPORTED {	\
@@ -41,6 +43,7 @@ enum ceph_feature_type {
 	CEPHFS_FEATURE_MULTI_RECONNECT,		\
 	CEPHFS_FEATURE_DELEG_INO,		\
 	CEPHFS_FEATURE_METRIC_COLLECT,		\
+	CEPHFS_FEATURE_NOTIFY_SESSION_STATE,	\
 }
 
 /*