fs: try to clone files first in vfs_copy_file_range

A clone is a perfectly fine implementation of a file copy, so most
file systems just implement the copy that way.  Instead of duplicating
this logic move it to the VFS.  Currently btrfs and XFS implement copies
the same way as clones and there is no behavior change for them, cifs
only implements clones and grow support for copy_file_range with this
patch.  NFS implements both, so this will allow copy_file_range to work
on servers that only implement CLONE and be lot more efficient on servers
that implements CLONE and COPY.

Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 0 insertions, 19 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 6e4f7f9..86ecc9b 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -909,24 +909,6 @@ out_unlock:
 	return error;
 }
 
-STATIC ssize_t
-xfs_file_copy_range(
-	struct file	*file_in,
-	loff_t		pos_in,
-	struct file	*file_out,
-	loff_t		pos_out,
-	size_t		len,
-	unsigned int	flags)
-{
-	int		error;
-
-	error = xfs_reflink_remap_range(file_in, pos_in, file_out, pos_out,
-				     len, false);
-	if (error)
-		return error;
-	return len;
-}
-
 STATIC int
 xfs_file_clone_range(
 	struct file	*file_in,
@@ -1625,7 +1607,6 @@ const struct file_operations xfs_file_operations = {
 	.fsync		= xfs_file_fsync,
 	.get_unmapped_area = thp_get_unmapped_area,
 	.fallocate	= xfs_file_fallocate,
-	.copy_file_range = xfs_file_copy_range,
 	.clone_file_range = xfs_file_clone_range,
 	.dedupe_file_range = xfs_file_dedupe_range,
 };