On Tue, Apr 15, 2014 at 06:34:38PM +0100, Filipe David Manana wrote: > On Tue, Apr 15, 2014 at 6:28 PM, Mark Fasheh <mfasheh@xxxxxxx> wrote: > > On Tue, Apr 15, 2014 at 05:40:18PM +0100, Filipe David Borba Manana wrote: > >> This increases the send stream version from version 1 to version 2, adding > >> 2 new commands: > >> > >> 1) total data size - used to tell the receiver how much file data the stream > >> will add or update; > >> > >> 2) fallocate - used to pre-allocate space for files and to punch holes in files. > >> > >> This is preparation work for subsequent changes that implement the new features > >> (computing total data size and use fallocate for better performance). > > > > Are these changes compatible with software using the old stream version? We > > have snapshotting tools that are using send/recieve and it would be bad to > > change the ABI in incompatible ways underneath them. > > --Mark > > New versions of btrfs-progs (send stream v2 support) will still be > able to read and process v1 streams. Older btrfs-progs (v1 only) won't > be able to process the new commands. > Does this answers your question Mark? Yes it does thanks. Unfortunately though this is unacceptable behavior - kernel upgrades are not supposed to break existing userspace interfaces. In particular what will happen here is that the user will grab a new kernel and then find out that their fancy snapshotting software won't work any more. --Mark -- Mark Fasheh -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
