xfs: don't cap maximum dedupe request length

After various discussions on linux-fsdevel, it has been decided that it
is not necessary to cap the length of a dedupe request, and that
correctly-written userspace client programs will be able to absorb the
change.  Therefore, remove the length clamping behavior.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_file.c

@@ -939,7 +939,6 @@ xfs_file_clone_range(
 				     len, false);
 }
 
-#define XFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
 STATIC ssize_t
 xfs_file_dedupe_range(
 	struct file	*src_file,
@@ -950,14 +949,6 @@ xfs_file_dedupe_range(
 {
 	int		error;
 
-	/*
-	 * Limit the total length we will dedupe for each operation.
-	 * This is intended to bound the total time spent in this
-	 * ioctl to something sane.
-	 */
-	if (len > XFS_MAX_DEDUPE_LEN)
-		len = XFS_MAX_DEDUPE_LEN;
-
 	error = xfs_reflink_remap_range(src_file, loff, dst_file, dst_loff,
 				     len, true);
 	if (error)