Hi Here I announce my new barrier support patches: http://people.redhat.com/mpatocka/patches/kernel/barriers/ They are for plain 2.6.28, if you applied Andi Kleen's partial-barrier patch, you need to revert it. My implementation work by offloading all the requests (both barrier and non-barrier ones) to a thread if the barrier is seen. The thread makes sure that it will flush all active requests before and after a barrier. When the thread finishes work, processing is switched back to dm_request. TODO: - doesn't support DM_ENDIO_REQUEUE, non-barrier DM_ENDIO_REQUEUE requests may be incorrectly reordered around a barrier, barrier DM_ENDIO_REQUEUE requests are aborted with an error. Needs redesign of DM_ENDIO_REQUEUE. - flushing hw disk cache in targets (especially snapshots and raid1) - on multipath it flushes hw cache on both paths, which is wrong (if one path has failed) - parallel flushing of hw caches on linear devices for better performance, currently they're being flushed sequentially Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
