ceph: kick flushing and flush snaps before sending normal cap message

Otherwise client may send cap flush messages in wrong order.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -2119,6 +2119,7 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
 
 retry:
 	spin_lock(&ci->i_ceph_lock);
+retry_locked:
 	if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
 		spin_unlock(&ci->i_ceph_lock);
 		dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
@@ -2126,8 +2127,6 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
 	}
 	if (ci->i_dirty_caps && ci->i_auth_cap) {
 		struct ceph_cap *cap = ci->i_auth_cap;
-		int used = __ceph_caps_used(ci);
-		int want = __ceph_caps_wanted(ci);
 		int delayed;
 
 		if (!session || session != cap->session) {
@@ -2143,13 +2142,24 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
 			goto out;
 		}
 
+		if (ci->i_ceph_flags &
+		    (CEPH_I_KICK_FLUSH | CEPH_I_FLUSH_SNAPS)) {
+			if (ci->i_ceph_flags & CEPH_I_KICK_FLUSH)
+				__kick_flushing_caps(mdsc, session, ci, 0);
+			if (ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)
+				__ceph_flush_snaps(ci, session);
+			goto retry_locked;
+		}
+
 		flushing = __mark_caps_flushing(inode, session, true,
 						&flush_tid, &oldest_flush_tid);
 
 		/* __send_cap drops i_ceph_lock */
 		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, true,
-				used, want, (cap->issued | cap->implemented),
-				flushing, flush_tid, oldest_flush_tid);
+				     __ceph_caps_used(ci),
+				     __ceph_caps_wanted(ci),
+				     (cap->issued | cap->implemented),
+				     flushing, flush_tid, oldest_flush_tid);
 
 		if (delayed) {
 			spin_lock(&ci->i_ceph_lock);