ceph: add column 'mds' to show caps in more user friendly

In multi-mds, the 'caps' debugfs file will have duplicate ino,
add the 'mds' column to indicate which mds session the cap belongs to.
Signed-off-by: Yanhu Cao <gmayyyha@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/debugfs.c

@@ -202,7 +202,8 @@ static int caps_show_cb(struct inode *inode, struct ceph_cap *cap, void *p)
 {
 	struct seq_file *s = p;
 
-	seq_printf(s, "0x%-17llx%-17s%-17s\n", ceph_ino(inode),
+	seq_printf(s, "0x%-17llx%-3d%-17s%-17s\n", ceph_ino(inode),
+		   cap->session->s_mds,
 		   ceph_cap_string(cap->issued),
 		   ceph_cap_string(cap->implemented));
 	return 0;
@@ -222,8 +223,8 @@ static int caps_show(struct seq_file *s, void *p)
 		   "reserved\t%d\n"
 		   "min\t\t%d\n\n",
 		   total, avail, used, reserved, min);
-	seq_printf(s, "ino                issued           implemented\n");
-	seq_printf(s, "-----------------------------------------------\n");
+	seq_printf(s, "ino              mds  issued           implemented\n");
+	seq_printf(s, "--------------------------------------------------\n");
 
 	mutex_lock(&mdsc->mutex);
 	for (i = 0; i < mdsc->max_sessions; i++) {