ceph: split large reconnect into multiple messages

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -2393,6 +2393,12 @@ void ceph_early_kick_flushing_caps(struct ceph_mds_client *mdsc,
 		if ((cap->issued & ci->i_flushing_caps) !=
 		    ci->i_flushing_caps) {
 			ci->i_ceph_flags &= ~CEPH_I_KICK_FLUSH;
+			/* encode_caps_cb() also will reset these sequence
+			 * numbers. make sure sequence numbers in cap flush
+			 * message match later reconnect message */
+			cap->seq = 0;
+			cap->issue_seq = 0;
+			cap->mseq = 0;
 			__kick_flushing_caps(mdsc, session, ci,
 					     oldest_flush_tid);
 		} else {

fs/ceph/mds_client.h

@@ -21,11 +21,13 @@
 #define CEPHFS_FEATURE_REPLY_ENCODING	9
 #define CEPHFS_FEATURE_RECLAIM_CLIENT	10
 #define CEPHFS_FEATURE_LAZY_CAP_WANTED	11
+#define CEPHFS_FEATURE_MULTI_RECONNECT  12
 
 #define CEPHFS_FEATURES_CLIENT_SUPPORTED { 	\
 	0, 1, 2, 3, 4, 5, 6, 7,			\
 	CEPHFS_FEATURE_MIMIC,			\
 	CEPHFS_FEATURE_LAZY_CAP_WANTED,		\
+	CEPHFS_FEATURE_MULTI_RECONNECT,		\
 }
 #define CEPHFS_FEATURES_CLIENT_REQUIRED {}
 
@@ -342,6 +344,7 @@ struct ceph_mds_client {
 	struct rw_semaphore     snap_rwsem;
 	struct rb_root          snap_realms;
 	struct list_head        snap_empty;
+	int			num_snap_realms;
 	spinlock_t              snap_empty_lock;  /* protect snap_empty */
 
 	u64                    last_tid;      /* most recent mds request */

fs/ceph/snap.c

@@ -124,6 +124,8 @@ static struct ceph_snap_realm *ceph_create_snap_realm(
 	INIT_LIST_HEAD(&realm->inodes_with_caps);
 	spin_lock_init(&realm->inodes_with_caps_lock);
 	__insert_snap_realm(&mdsc->snap_realms, realm);
+	mdsc->num_snap_realms++;
+
 	dout("create_snap_realm %llx %p\n", realm->ino, realm);
 	return realm;
 }
@@ -175,6 +177,7 @@ static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
 	dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
 
 	rb_erase(&realm->node, &mdsc->snap_realms);
+	mdsc->num_snap_realms--;
 
 	if (realm->parent) {
 		list_del_init(&realm->child_item);