On Sat, May 28, 2016 at 10:27:55AM +0100, Sitsofe Wheeler wrote: > On Sat, May 28, 2016 at 08:55:43AM +0000, Sitsofe Wheeler wrote: > > On Thu, May 26, 2016 at 11:08:14AM -0700, Shaohua Li wrote: > > > blkdev_issue_zeroout try discard/writesame first, if they fail, zeroout > > > fallback to regular write. The problem is discard/writesame doesn't > > > return error for -EOPNOTSUPP, then zeroout can't do fallback and leave > > > disk data not changed. zeroout should have guaranteed zero-fill > > > behavior. > > > > It sounds like at least this patch should go in so BLKZEROOUT can always > > fall back (since those zeros are essential) but it would still be nice > > to see the disabling of write same being copied up to md device's > > write_same_max_bytes so everyone knows not to try using it in the future > > but perhaps someone will say "what if I re-enable it on the device > > below?" etc. > > I've tested Shaohua's original patch on top of Linus' tree and even > without the suggested changes (above and below) it at least resolves the > success being returned but data not being zeroed (with both PVSCSI and > scsi_debug underlying devices) issue so: > > Tested-by: Sitsofe Wheeler <sitsofe@xxxxxxxxx> Jens, any chance you could merge this one? I'll fix the MD part later and make sure write_same_max_bytes sets to 0 after IO failure. Thanks, Shaohua -- 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
