udf: add llseek method

UDF currently doesn't set a llseek method for regular files, which
means it will fall back to default_llseek.  This means no one can seek
beyond 2 Gigabytes on udf, and that there's not protection vs
the i_size updates from writers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/file.c

@@ -211,6 +211,7 @@ const struct file_operations udf_file_operations = {
 	.release		= udf_release_file,
 	.fsync			= udf_fsync_file,
 	.splice_read		= generic_file_splice_read,
+	.llseek			= generic_file_llseek,
 };
 
 const struct inode_operations udf_file_inode_operations = {