[SMB3] Display persistenthandles in /proc/mounts for SMB3 shares if enabled

Signed-off-by: Steve French <steve.french@primarydata.com>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>

fs/cifs/cifsfs.c

@@ -454,6 +454,8 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
 		seq_puts(s, ",nocase");
 	if (tcon->retry)
 		seq_puts(s, ",hard");
+	if (tcon->use_persistent)
+		seq_puts(s, ",persistenthandles");
 	if (tcon->unix_ext)
 		seq_puts(s, ",unix");
 	else