ceph: release cap on import if we don't have the inode

If we get an IMPORT that give us a cap, but we don't have the inode, queue
a release (and try to send it immediately) so that the MDS doesn't get
stuck waiting for us.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/caps.c

@@ -981,19 +981,10 @@ static int send_cap_msg(struct ceph_mds_session *session,
 	return 0;
 }
 
-/*
- * Queue cap releases when an inode is dropped from our cache.  Since
- * inode is about to be destroyed, there is no need for i_lock.
- */
-void ceph_queue_caps_release(struct inode *inode)
+static void __queue_cap_release(struct ceph_mds_session *session,
+				u64 ino, u64 cap_id, u32 migrate_seq,
+				u32 issue_seq)
 {
-	struct ceph_inode_info *ci = ceph_inode(inode);
-	struct rb_node *p;
-
-	p = rb_first(&ci->i_caps);
-	while (p) {
-		struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
-		struct ceph_mds_session *session = cap->session;
 	struct ceph_msg *msg;
 	struct ceph_mds_cap_release *head;
 	struct ceph_mds_cap_item *item;
@@ -1003,25 +994,24 @@ void ceph_queue_caps_release(struct inode *inode)
 	msg = list_first_entry(&session->s_cap_releases,
 			       struct ceph_msg, list_head);
 
-		dout(" adding %p release to mds%d msg %p (%d left)\n",
-		     inode, session->s_mds, msg, session->s_num_cap_releases);
+	dout(" adding %llx release to mds%d msg %p (%d left)\n",
+	     ino, session->s_mds, msg, session->s_num_cap_releases);
 
 	BUG_ON(msg->front.iov_len + sizeof(*item) > PAGE_CACHE_SIZE);
 	head = msg->front.iov_base;
 	head->num = cpu_to_le32(le32_to_cpu(head->num) + 1);
 	item = msg->front.iov_base + msg->front.iov_len;
-		item->ino = cpu_to_le64(ceph_ino(inode));
-		item->cap_id = cpu_to_le64(cap->cap_id);
-		item->migrate_seq = cpu_to_le32(cap->mseq);
-		item->seq = cpu_to_le32(cap->issue_seq);
+	item->ino = cpu_to_le64(ino);
+	item->cap_id = cpu_to_le64(cap_id);
+	item->migrate_seq = cpu_to_le32(migrate_seq);
+	item->seq = cpu_to_le32(issue_seq);
 
 	session->s_num_cap_releases--;
 
 	msg->front.iov_len += sizeof(*item);
 	if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
 		dout(" release msg %p full\n", msg);
-			list_move_tail(&msg->list_head,
-				       &session->s_cap_releases_done);
+		list_move_tail(&msg->list_head, &session->s_cap_releases_done);
 	} else {
 		dout(" release msg %p at %d/%d (%d)\n", msg,
 		     (int)le32_to_cpu(head->num),
@@ -1029,6 +1019,24 @@ void ceph_queue_caps_release(struct inode *inode)
 		     (int)msg->front.iov_len);
 	}
 	spin_unlock(&session->s_cap_lock);
+}
+
+/*
+ * Queue cap releases when an inode is dropped from our cache.  Since
+ * inode is about to be destroyed, there is no need for i_lock.
+ */
+void ceph_queue_caps_release(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct rb_node *p;
+
+	p = rb_first(&ci->i_caps);
+	while (p) {
+		struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
+		struct ceph_mds_session *session = cap->session;
+
+		__queue_cap_release(session, ceph_ino(inode), cap->cap_id,
+				    cap->mseq, cap->issue_seq);
 		p = rb_next(p);
 		__ceph_remove_cap(cap);
 	}
@@ -2655,7 +2663,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 	struct ceph_mds_caps *h;
 	int mds = session->s_mds;
 	int op;
-	u32 seq;
+	u32 seq, mseq;
 	struct ceph_vino vino;
 	u64 cap_id;
 	u64 size, max_size;
@@ -2675,6 +2683,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 	vino.snap = CEPH_NOSNAP;
 	cap_id = le64_to_cpu(h->cap_id);
 	seq = le32_to_cpu(h->seq);
+	mseq = le32_to_cpu(h->migrate_seq);
 	size = le64_to_cpu(h->size);
 	max_size = le64_to_cpu(h->max_size);
 
@@ -2689,6 +2698,17 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 	     vino.snap, inode);
 	if (!inode) {
 		dout(" i don't have ino %llx\n", vino.ino);
+
+		if (op == CEPH_CAP_OP_IMPORT)
+			__queue_cap_release(session, vino.ino, cap_id,
+					    mseq, seq);
+
+		/*
+		 * send any full release message to try to move things
+		 * along for the mds (who clearly thinks we still have this
+		 * cap).
+		 */
+		ceph_send_cap_releases(mdsc, session);
 		goto done;
 	}
 

fs/ceph/mds_client.c

@@ -1176,7 +1176,7 @@ static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
 /*
  * called under s_mutex
  */
-static void send_cap_releases(struct ceph_mds_client *mdsc,
+void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
 			    struct ceph_mds_session *session)
 {
 	struct ceph_msg *msg;
@@ -2693,7 +2693,7 @@ static void delayed_work(struct work_struct *work)
 		add_cap_releases(mdsc, s, -1);
 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
 		    s->s_state == CEPH_MDS_SESSION_HUNG)
-			send_cap_releases(mdsc, s);
+			ceph_send_cap_releases(mdsc, s);
 		mutex_unlock(&s->s_mutex);
 		ceph_put_mds_session(s);
 

fs/ceph/mds_client.h

@@ -322,6 +322,9 @@ static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
 	kref_put(&req->r_kref, ceph_mdsc_release_request);
 }
 
+extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session);
+
 extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);
 
 extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,