On Wed, Sep 01 2010 at 1:07pm -0400, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Wed, Sep 01 2010 at 11:35am -0400, > Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > > > On Wed, 1 Sep 2010, Mike Snitzer wrote: > > > > > > Mikulas, > > > > > > Current bio-based barrier support also defers IO if a flush is in > > > progress. See _dm_request: > > > > I know. But it doesn't hurt with flush/fua requests. It just lowers > > performance (it defers i/os when it doesn't have to) but doesn't damage > > data. > > > > So I think that we can let it be this way until flush/fua patch is > > finalized. > > Neither Tejun nor I see the point in waiting when we have a window of > time to address the issues now. We want DM to realize the benefit > associated with the kernel-wide FLUSH+FUA conversion too. But we can meet in the middle. I've reordered the DM FLUSH+FUA patches so that the more intrusive bio-based relaxed ordering patch is at the very end. My hope was that the request-based deadlock I'm seeing would disappear if that relaxed ordering patch wasn't applied. Unfortunately, I still see the hang. Anyway, I've made the patches available here: http://people.redhat.com/msnitzer/patches/flush-fua/ -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
