ceph: simplify add_cap_releases

No functional change, aside from more useful debug output.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/mds_client.c

@@ -1069,11 +1069,14 @@ static int trim_caps(struct ceph_mds_client *mdsc,
 int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
 			  struct ceph_mds_session *session)
 {
-	struct ceph_msg *msg;
+	struct ceph_msg *msg, *partial = NULL;
 	struct ceph_mds_cap_release *head;
 	int err = -ENOMEM;
 	int extra = mdsc->client->mount_args->cap_release_safety;
+	int num;
 
+	dout("add_cap_releases %p mds%d extra %d\n", session, session->s_mds,
+	     extra);
 
 	spin_lock(&session->s_cap_lock);
 
@@ -1082,9 +1085,14 @@ int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
 				       struct ceph_msg,
 				 list_head);
 		head = msg->front.iov_base;
-		extra += CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
+		num = le32_to_cpu(head->num);
+		if (num) {
+			dout(" partial %p with (%d/%d)\n", msg, num,
+			     (int)CEPH_CAPS_PER_RELEASE);
+			extra += CEPH_CAPS_PER_RELEASE - num;
+			partial = msg;
+		}
 	}
-
 	while (session->s_num_cap_releases < session->s_nr_caps + extra) {
 		spin_unlock(&session->s_cap_lock);
 		msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
@@ -1101,19 +1109,14 @@ int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
 		session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
 	}
 
-	if (!list_empty(&session->s_cap_releases)) {
-		msg = list_first_entry(&session->s_cap_releases,
-				       struct ceph_msg,
-				       list_head);
-		head = msg->front.iov_base;
-		if (head->num) {
-			dout(" queueing non-full %p (%d)\n", msg,
-			     le32_to_cpu(head->num));
-			list_move_tail(&msg->list_head,
-				      &session->s_cap_releases_done);
-			session->s_num_cap_releases -=
-				CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
-		}
+	if (partial) {
+		head = partial->front.iov_base;
+		num = le32_to_cpu(head->num);
+		dout(" queueing partial %p with %d/%d\n", partial, num,
+		     (int)CEPH_CAPS_PER_RELEASE);
+		list_move_tail(&partial->list_head,
+			       &session->s_cap_releases_done);
+		session->s_num_cap_releases -= CEPH_CAPS_PER_RELEASE - num;
 	}
 	err = 0;
 	spin_unlock(&session->s_cap_lock);