ceph: have __mark_caps_flushing return flush_tid

Currently, this function returns ci->i_dirty_caps, but the callers have
to check that that isn't 0 before calling this function. Have the
callers grab that value directly out of the inode, and have
__mark_caps_flushing return the flush_tid instead.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -1722,11 +1722,11 @@ static bool __finish_cap_flush(struct ceph_mds_client *mdsc,
  * Add dirty inode to the flushing list.  Assigned a seq number so we
  * can wait for caps to flush without starving.
  *
- * Called under i_ceph_lock.
+ * Called under i_ceph_lock. Returns the flush tid.
  */
-static int __mark_caps_flushing(struct inode *inode,
+static u64 __mark_caps_flushing(struct inode *inode,
 				struct ceph_mds_session *session, bool wake,
-				u64 *flush_tid, u64 *oldest_flush_tid)
+				u64 *oldest_flush_tid)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
 	struct ceph_inode_info *ci = ceph_inode(inode);
@@ -1765,8 +1765,7 @@ static int __mark_caps_flushing(struct inode *inode,
 
 	list_add_tail(&cf->i_list, &ci->i_cap_flush_list);
 
-	*flush_tid = cf->tid;
-	return flushing;
+	return cf->tid;
 }
 
 /*
@@ -2056,8 +2055,8 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
 		}
 
 		if (cap == ci->i_auth_cap && ci->i_dirty_caps) {
-			flushing = __mark_caps_flushing(inode, session, false,
-							&flush_tid,
+			flushing = ci->i_dirty_caps;
+			flush_tid = __mark_caps_flushing(inode, session, false,
 							 &oldest_flush_tid);
 		} else {
 			flushing = 0;
@@ -2137,8 +2136,9 @@ static int try_flush_caps(struct inode *inode, u64 *ptid)
 			goto retry_locked;
 		}
 
-		flushing = __mark_caps_flushing(inode, session, true,
-						&flush_tid, &oldest_flush_tid);
+		flushing = ci->i_dirty_caps;
+		flush_tid = __mark_caps_flushing(inode, session, true,
+						 &oldest_flush_tid);
 
 		/* __send_cap drops i_ceph_lock */
 		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,