On Wed, Jan 13, 2021 at 11:43:50AM +0100, Arthur Borsboom wrote: > When performing the following command in a Xen VM the call trace below is > generated. > > sudo fstrim -v / > > Xen VM host: Xen 4.14.0 > Xen Dom0: Linux 4.19.14 > Xen DomX: Linux 5.10.6 > > The code in the kernel triggering this trace is the following. > > /* In case the discard granularity isn't set by buggy device driver > */ > if (WARN_ON_ONCE(!q->limits.discard_granularity)) { > char dev_name[BDEVNAME_SIZE]; > > bdevname(bdev, dev_name); > pr_err_ratelimited("%s: Error: discard_granularity is > 0.\n", dev_name); > return -EOPNOTSUPP; > }
So it seems like the underlying storage in dom0 doesn't support discard, and hence the feature don't get setup on the frontend? Can you print the output of `xenstore-ls -fp` executed from dom0 when the guest is running? That way I could see which features the backend is exposing. Thanks, Roger.