On Sun, 7 Dec 2008 22:41:19 -0500 (EST) Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > I released new patches for shared snapshots. The functionality is the same > as in previous releases, but the two snapshot exception stores, one > created by Fujita Tomonori and one by me, are consolidated and common code > is shared. > > The patches are at: > http://people.redhat.com/mpatocka/patches/kernel/new-snapshots/ Thanks, As I said before, I have no preference about how to integrate new snapshot implementations into the existing code. I'm happy to follow the maintainer, Alasdair? > The patches don't alter existing snapshot implementation, they contain > just new files (they alter only Kconfig and Makefile to make the new files > compilable). > > The new architecture is as follows: > > The module dm-multisnapshot.ko contains common code for both exception > stores. It has basically processing and queuing IOs and attaching > snapshots and interfacing with device mapper. I've not closely looked at your dm-multisnapshot but after a quick look, I'm not sure about the number of exception I/Os (except for metadata I/Os) with an origin write. For example, I create five snapshots and remove the 1 and 3 snapshots (*1). Now I have 0, 2, 4 snapshots. Then when I update the origin, how many exception I/Os dm-multisnapshot needs to perform? (*1) I know dm-multisnapshot doesn't support deleting a snapshot for now, but I expect that it will support it in the future. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
