On Wed, May 04, 2016 at 11:20:38AM -0400, Mike Snitzer wrote: > > > Commit 38f25255330 ("block: add __blkdev_issue_discard") incorrectly > > > disallowed the return of -EOPNOTSUPP if the device didn't support > > > discard (or secure discard). > > > > I assume dm relied in this? The different handling of early vs > > late -EOPNOTSUPP is the old code is rather odd, so when restoring > > it I'd rather have a comment explaining why the different handling > > is needed. > > It isn't needed by DM. The device-mapper-test-suite's thinp discard > tests did catch the change in behaviour but that is besides the point. > > Why do you feel it makes sense to mask the fact that discards issued to > a device that doesn't support them is unsupported? Especially when it > is established behavior of the blkdev_issue_discard() interface to do > so. > > I see no point in breaking established behaviour. If you do then please > explain. Let's take a step back and define at what point ENOTSUPP should be ignored, and until when it should not. Once we have a good answer to that question I'd be happy with updating the kernel. Are you / dm fine with always returning ENOTSUPP? -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html