On Mon, 28 Jun 2010 09:57:38 +0200 Christoph Hellwig <hch@xxxxxx> wrote: > On Sun, Jun 27, 2010 at 09:32:07PM +0900, FUJITA Tomonori wrote: > > On Sun, 27 Jun 2010 13:07:12 +0200 > > Christoph Hellwig <hch@xxxxxx> wrote: > > > > > > How about this? > > > > > > As I tried to explain before this utterly confuses the I/O completion > > > path. With the patch applied even a simple mkfs.xfs that issues discard > > > just hangs. > > > > Wired. I just tried mkfs.xfs against scsi_debug with my block patches > > (I saw one discard command). Seemed that it worked fine. > > I've tracked it down to the call to scsi_requeue_command in scsi_end_request. > When the command is marked BLOCK_PC we'll just get it back as such in > ->prep_fn next time, but now it's reverting to the previous state. If scsi_end_request() calls scsi_requeue_command(), the command has a left over (i.e. hasn't finished all the data), right? You hit such condition with discard commands? BLOCK_PC requests don't hit this case since blk_end_request() always return false for PC. > While I see the problems with leaking ressources in that case I still > can't quite explain the hang I see. Any way to reproduce the hang without ssd drives? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
