Push BKL down into ->remount_fs()

[xfs, btrfs, capifs, shmem don't need BKL, exempt]

Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 04802cc..6832135 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -568,6 +568,7 @@
 	if (!udf_parse_options(options, &uopt, true))
 		return -EINVAL;
 
+	lock_kernel();
 	sbi->s_flags = uopt.flags;
 	sbi->s_uid   = uopt.uid;
 	sbi->s_gid   = uopt.gid;
@@ -581,13 +582,16 @@
 			*flags |= MS_RDONLY;
 	}
 
-	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
+		unlock_kernel();
 		return 0;
+	}
 	if (*flags & MS_RDONLY)
 		udf_close_lvid(sb);
 	else
 		udf_open_lvid(sb);
 
+	unlock_kernel();
 	return 0;
 }