I just verified that cp --reflink (which for cifs.ko smb3 mounts invokes the DUPLICATE_EXTENTS SMB3 fcntl) works to current Windows Server 2016 (TP5) as long as the target share is on an REFS partition (not NTFS). Very cool - even faster than CopyChunk for server side copy. -- Thanks, Steve -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html