ceph: record updated mon_addr on remount

Note that the new monitors are just shown in /proc/mounts.
Ceph does not (re)connect to new monitors yet.

[ jlayton: s/printk\(KERN_NOTICE/pr_notice(/
	   s/strcmp/strcmp_null/ ]

Signed-off-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Author: vshankar

fs/ceph/super.c

@@ -1277,6 +1277,13 @@ static int ceph_reconfigure_fc(struct fs_context *fc)
 	else
 		ceph_clear_mount_opt(fsc, ASYNC_DIROPS);
 
+	if (strcmp_null(fsc->mount_options->mon_addr, fsopt->mon_addr)) {
+		kfree(fsc->mount_options->mon_addr);
+		fsc->mount_options->mon_addr = fsopt->mon_addr;
+		fsopt->mon_addr = NULL;
+		pr_notice("ceph: monitor addresses recorded, but not used for reconnection");
+	}
+
 	sync_filesystem(fc->root->d_sb);
 	return 0;
 }