ceph: add ceph_get_cap_for_mds function.

Signed-off-by: NGreg Farnum <gregf@hq.newdream.net>
Signed-off-by: NSage Weil <sage@newdream.net>

fs/ceph/caps.c

@@ -327,6 +327,16 @@ static struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
 	return NULL;
 }
 
+struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci, int mds)
+{
+	struct ceph_cap *cap;
+
+	spin_lock(&ci->vfs_inode.i_lock);
+	cap = __get_cap_for_mds(ci, mds);
+	spin_unlock(&ci->vfs_inode.i_lock);
+	return cap;
+}
+
 /*
  * Return id of any MDS with a cap, preferably FILE_WR|BUFFER|EXCL, else -1.
  */

fs/ceph/super.h

@@ -816,6 +816,8 @@ extern int ceph_write_inode(struct inode *inode, struct writeback_control *wbc);
 extern int ceph_fsync(struct file *file, int datasync);
 extern void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
 				    struct ceph_mds_session *session);
+extern struct ceph_cap *ceph_get_cap_for_mds(struct ceph_inode_info *ci,
+					     int mds);
 extern int ceph_get_cap_mds(struct inode *inode);
 extern void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps);
 extern void ceph_put_cap_refs(struct ceph_inode_info *ci, int had);