On Thu, Jul 08 2010 at 11:52am -0400, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > > > On Thu, 8 Jul 2010, Mike Snitzer wrote: > > Doesn't store_barrier_error just record the result of the first empty > > barrier (not the -EOPNOTSUPP result of the unsupported discard)? > > > > I'm missing how this change helps avoid the 2nd barrier for the > > -EOPNOTSUPP discard case. > > > > ... And my testing shows that it doesn't. > > > > Mike > > Thanks for testing it. The errors of all the operations are accumulated in > in md->barrier_error in dec_pending. > > The problem was that it was ignoring -EOPNOTSUPP (assuming to ignore not > supported empty barriers), but this condition unexpectedly ignored > EOPNOTSUPP from the discard as well. > > Please test with this patch. > > Also, apply the patch to RHEL, because it is a bugfix (don't ignore > discard errors). > > Mikulas > > --- > > dm barrier: A better test for -EOPNOTSUPP. > > -EOPNOTSUPP could be generated only by empty barriers and we ignored that > error, assuming that device not supporting cache flushes has cache always > consistent. > > With addition of discard barriers, this -EOPNOTSUPP could be generated by > discards as well, and we can't ignore it. > > This patch refines the test for -EOPNOTSUPP, ignoring it only for empty > barrier requests. > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Works great, thanks. Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx> -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
