vfs: combine the clone and dedupe into a single remap_file_range

Combine the clone_file_range and dedupe_file_range operations into a
single remap_file_range file operation dispatch since they're
fundamentally the same operation.  The differences between the two can
be made in the prep functions.

Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Amir Goldstein <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Dave Chinner <[email protected]>

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 7b7b845..e6d4466 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -622,3 +622,8 @@
 	alloc_file_clone(file, flags, ops) does not affect any caller's references.
 	On success you get a new struct file sharing the mount/dentry with the
 	original, on failure - ERR_PTR().
+--
+[mandatory]
+	->clone_file_range() and ->dedupe_file_range have been replaced with
+	->remap_file_range().  See Documentation/filesystems/vfs.txt for more
+	information.