ceph: update wanted caps after resuming stale session

mds contains an optimization, it does not re-issue stale caps if
client does not want any cap.

A special case of the optimization is that client wants some caps,
but skipped updating 'wanted'. For this case, client needs to update
'wanted' when stale session get renewed.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -657,6 +657,9 @@ void ceph_add_cap(struct inode *inode,
 		session->s_nr_caps++;
 		spin_unlock(&session->s_cap_lock);
 	} else {
+		if (cap->cap_gen < session->s_cap_gen)
+			cap->issued = cap->implemented = CEPH_CAP_PIN;
+
 		/*
 		 * auth mds of the inode changed. we received the cap export
 		 * message, but still haven't received the cap import message.
@@ -3065,21 +3068,6 @@ static void handle_cap_grant(struct inode *inode,
 		inode->i_size);
 
 
-	/*
-	 * auth mds of the inode changed. we received the cap export message,
-	 * but still haven't received the cap import message. handle_cap_export
-	 * updated the new auth MDS' cap.
-	 *
-	 * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing a message
-	 * that was sent before the cap import message. So don't remove caps.
-	 */
-	if (ceph_seq_cmp(seq, cap->seq) <= 0) {
-		WARN_ON(cap != ci->i_auth_cap);
-		WARN_ON(cap->cap_id != le64_to_cpu(grant->cap_id));
-		seq = cap->seq;
-		newcaps |= cap->issued;
-	}
-
 	/*
 	 * If CACHE is being revoked, and we have no dirty buffers,
 	 * try to invalidate (once).  (If there are dirty buffers, we
@@ -3099,6 +3087,24 @@ static void handle_cap_grant(struct inode *inode,
 		}
 	}
 
+	if (was_stale)
+		cap->issued = cap->implemented = CEPH_CAP_PIN;
+
+	/*
+	 * auth mds of the inode changed. we received the cap export message,
+	 * but still haven't received the cap import message. handle_cap_export
+	 * updated the new auth MDS' cap.
+	 *
+	 * "ceph_seq_cmp(seq, cap->seq) <= 0" means we are processing a message
+	 * that was sent before the cap import message. So don't remove caps.
+	 */
+	if (ceph_seq_cmp(seq, cap->seq) <= 0) {
+		WARN_ON(cap != ci->i_auth_cap);
+		WARN_ON(cap->cap_id != le64_to_cpu(grant->cap_id));
+		seq = cap->seq;
+		newcaps |= cap->issued;
+	}
+
 	/* side effects now are allowed */
 	cap->cap_gen = session->s_cap_gen;
 	cap->seq = seq;
@@ -3549,9 +3555,9 @@ static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
 		goto out_unlock;
 
 	if (target < 0) {
-		__ceph_remove_cap(cap, false);
-		if (!ci->i_auth_cap)
+		if (cap->mds_wanted | cap->issued)
 			ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
+		__ceph_remove_cap(cap, false);
 		goto out_unlock;
 	}
 

fs/ceph/mds_client.c

@@ -1232,13 +1232,13 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 	dout("removing cap %p, ci is %p, inode is %p\n",
 	     cap, ci, &ci->vfs_inode);
 	spin_lock(&ci->i_ceph_lock);
+	if (cap->mds_wanted | cap->issued)
+		ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
 	__ceph_remove_cap(cap, false);
 	if (!ci->i_auth_cap) {
 		struct ceph_cap_flush *cf;
 		struct ceph_mds_client *mdsc = fsc->mdsc;
 
-		ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
-
 		if (ci->i_wrbuffer_ref > 0 &&
 		    READ_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
 			invalidate = true;
@@ -1355,6 +1355,12 @@ static void remove_session_caps(struct ceph_mds_session *session)
 	dispose_cap_releases(session->s_mdsc, &dispose);
 }
 
+enum {
+	RECONNECT,
+	RENEWCAPS,
+	FORCE_RO,
+};
+
 /*
  * wake up any threads waiting on this session's caps.  if the cap is
  * old (didn't get renewed on the client reconnect), remove it now.
@@ -1365,23 +1371,34 @@ static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
 			      void *arg)
 {
 	struct ceph_inode_info *ci = ceph_inode(inode);
+	unsigned long ev = (unsigned long)arg;
 
-	if (arg) {
+	if (ev == RECONNECT) {
 		spin_lock(&ci->i_ceph_lock);
 		ci->i_wanted_max_size = 0;
 		ci->i_requested_max_size = 0;
 		spin_unlock(&ci->i_ceph_lock);
+	} else if (ev == RENEWCAPS) {
+		if (cap->cap_gen < cap->session->s_cap_gen) {
+			/* mds did not re-issue stale cap */
+			spin_lock(&ci->i_ceph_lock);
+			cap->issued = cap->implemented = CEPH_CAP_PIN;
+			/* make sure mds knows what we want */
+			if (__ceph_caps_file_wanted(ci) & ~cap->mds_wanted)
+				ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
+			spin_unlock(&ci->i_ceph_lock);
+		}
+	} else if (ev == FORCE_RO) {
 	}
 	wake_up_all(&ci->i_cap_wq);
 	return 0;
 }
 
-static void wake_up_session_caps(struct ceph_mds_session *session,
-				 int reconnect)
+static void wake_up_session_caps(struct ceph_mds_session *session, int ev)
 {
 	dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
 	iterate_session_caps(session, wake_up_session_cb,
-			     (void *)(unsigned long)reconnect);
+			     (void *)(unsigned long)ev);
 }
 
 /*
@@ -1466,7 +1483,7 @@ static void renewed_caps(struct ceph_mds_client *mdsc,
 	spin_unlock(&session->s_cap_lock);
 
 	if (wake)
-		wake_up_session_caps(session, 0);
+		wake_up_session_caps(session, RENEWCAPS);
 }
 
 /*
@@ -2847,7 +2864,7 @@ static void handle_session(struct ceph_mds_session *session,
 		spin_lock(&session->s_cap_lock);
 		session->s_readonly = true;
 		spin_unlock(&session->s_cap_lock);
-		wake_up_session_caps(session, 0);
+		wake_up_session_caps(session, FORCE_RO);
 		break;
 
 	case CEPH_SESSION_REJECT:
@@ -3339,7 +3356,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 				pr_info("mds%d recovery completed\n", s->s_mds);
 			kick_requests(mdsc, i);
 			ceph_kick_flushing_caps(mdsc, s);
-			wake_up_session_caps(s, 1);
+			wake_up_session_caps(s, RECONNECT);
 		}
 	}
 

fs/ceph/mds_client.h

@@ -18,13 +18,15 @@
 
 /* The first 8 bits are reserved for old ceph releases */
 #define CEPHFS_FEATURE_MIMIC		8
+#define CEPHFS_FEATURE_REPLY_ENCODING	9
+#define CEPHFS_FEATURE_RECLAIM_CLIENT	10
+#define CEPHFS_FEATURE_LAZY_CAP_WANTED	11
 
-#define CEPHFS_FEATURES_ALL {           \
+#define CEPHFS_FEATURES_CLIENT_SUPPORTED { 	\
 	0, 1, 2, 3, 4, 5, 6, 7,			\
 	CEPHFS_FEATURE_MIMIC,			\
+	CEPHFS_FEATURE_LAZY_CAP_WANTED,		\
 }
-
-#define CEPHFS_FEATURES_CLIENT_SUPPORTED CEPHFS_FEATURES_ALL
 #define CEPHFS_FEATURES_CLIENT_REQUIRED {}