On Wed, Oct 28 2009, Mike Snitzer wrote: > On Wed, Oct 28 2009 at 4:19pm -0400, > Andrew Patterson <andrew.patterson@xxxxxx> wrote: > > > On Thu, 2009-08-06 at 21:50 -0400, Mikulas Patocka wrote: > > > On Thu, 6 Aug 2009, Alasdair G Kergon wrote: > > > > > > > On Thu, Aug 06, 2009 at 12:14:17PM +0100, Mark McLoughlin wrote: > > > > > We should error all barriers, even empty barriers, on devices like > > > > > virtio_blk which don't support them. > > > > > > > > Have you considered whether or not virtio_blk actually needs to > > > > support empty barriers? > > > > > > > > Alasdair > > > > > > This is only for request-based drivers, where it is the responsibility of > > > blk-core to translate barriers. I think the empty barrier request anyway > > > in blk_do_ordered, but with an error message. So the patch changes it to > > > discard it early and queitly. It seems ok. > > > > > > Mikulas > > > -- > > > > This patch seems to have been dropped. I can reproduce the error using > > the following: > > > > 1. Create an LVM logical volume on top of a cciss device (note that > > the cciss driver does not support barriers) > > 2. Create an ext3 file system on top of the logical volume > > 3. Mount the file-system using -obarrier=1 > > 4. Copy some files onto the file-system > > 5. Run sync (dm_flush is called) > > > > If I apply the patch (with some munging), the > > > > "end_request: I/O error, dev cciss/cXdY, sector 0" > > > > messages go away. > > > > This is not strictly a regression, given that the problem was introduced > > in 2.6.31, but I think it should still be fixed for 2.6.32. > > It was resubmitted last Friday: > http://lkml.org/lkml/2009/10/23/196 > > And is queued in Jens' 'for-linus' branch (meaning it should get > upstream in time for 2.6.32), see: > http://git.kernel.org/?p=linux/kernel/git/axboe/linux-2.6-block.git;a=commit;h=6cafb12dc85a5bdc722791cc5070968413264909 I sent out a pull request yesterday, but it isn't in yet. Any day now... -- Jens Axboe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
