ubifs: Reject unsupported ioctl flags explicitly

Reject unsupported ioctl flags explicitly, so the following command
on a regular ubifs file will fail:
	chattr +d ubifs_file

And xfstests generic/424 will pass.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/ioctl.c

@@ -28,6 +28,11 @@
 #include <linux/mount.h>
 #include "ubifs.h"
 
+/* Need to be kept consistent with checked flags in ioctl2ubifs() */
+#define UBIFS_SUPPORTED_IOCTL_FLAGS \
+	(FS_COMPR_FL | FS_SYNC_FL | FS_APPEND_FL | \
+	 FS_IMMUTABLE_FL | FS_DIRSYNC_FL)
+
 /**
  * ubifs_set_inode_flags - set VFS inode flags.
  * @inode: VFS inode to set flags for
@@ -169,6 +174,9 @@ long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		if (get_user(flags, (int __user *) arg))
 			return -EFAULT;
 
+		if (flags & ~UBIFS_SUPPORTED_IOCTL_FLAGS)
+			return -EOPNOTSUPP;
+
 		if (!S_ISDIR(inode->i_mode))
 			flags &= ~FS_DIRSYNC_FL;