On Fri, Aug 09, 2019 at 04:26:10PM -0500, Mike Christie wrote: > This fixes a regression added in 4.9 with commit: > > commit 0eadf37afc2500e1162c9040ec26a705b9af8d47 > Author: Josef Bacik <jbacik@xxxxxx> > Date: Thu Sep 8 12:33:40 2016 -0700 > > nbd: allow block mq to deal with timeouts > > where before the patch userspace would set the timeout to 0 to disable > it. With the above patch, a zero timeout tells the block layer to use > the default value of 30 seconds. For setups where commands can take a > long time or experience transient issues like network disruptions this > then results in IO errors being sent to the application. > > To fix this, the patch still uses the common block layer timeout > framework, but if zero is set, nbd just logs a message and then resets > the timer when it expires. > > Josef, > > I did not cc stable, but I think we want to port the patches to some > releases. We originally hit this with users using the longterm kernels > with ceph. The patch does not apply anywhere cleanly with older ones > like 4.9, so I was not sure how we wanted to handle it. > I assume you tested this? IIRC there was a problem where 0 really meant 0 and commands would insta-timeout. But my memory is foggy here, so I'm not sure if it was setting the tag_set timeout to 0 that made things go wrong, or what. Or I could be making it all up, who knows. There's a blktest that just runs fio on a normal device with no timeouts or anything, that's where I would see the problem since it was a little racy. Basically have the timeout set to 0 and put load on the disk and eventually you'd start seeing timeouts. If that all goes fine then you can add Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Thanks, Josef
