On Tue, 28 May 2024 at 13:23, Alexander Larsson <alexl@xxxxxxxxxx> wrote: > > > > On Tue, May 28, 2024 at 1:34 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >> >> On Tue, 28 May 2024 at 12:55, Eric Curtin <ecurtin@xxxxxxxxxx> wrote: >> > >> > On Tue, 28 May 2024 at 11:34, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >> > > >> > > On Tue, 28 May 2024 at 11:03, Eric Curtin <ecurtin@xxxxxxxxxx> wrote: >> > > > >> > > > In some deployments, an empty lowerdir is not considered an error. >> > > >> > > I don't think this can be triggered in upstream kernel and can be >> > > removed completely. >> > >> > True... Just switched to Fedora Rawhide and instead we just see this one: >> > >> > pr_err("cannot append lower layer"); >> > >> > > >> > > Or do you have a reproducer? >> > >> > Run one of these vms: >> > >> > https://github.com/osbuild/bootc-image-builder >> >> Apparently it is using the legacy lowerdir append mode >> "lowerdir=:foo". This works only on 6.5. >> >> In 6.6 and later the same can be achieved with "lowerdir+=foo". >> >> It's strange that there are not side effects other then the error message. > > > The code tries to use the new mode, but then falls back on ENOSYS: > > https://github.com/containers/composefs/blob/main/libcomposefs/lcfs-mount.c#L431 > > So, I guess with a more recent kernel it will not print the warning. > > -- > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > Alexander Larsson Red Hat, Inc > alexl@xxxxxxxxxx alexander.larsson@xxxxxxxxx I realized I never posted the version of the kernel producing this error message: pr_err("cannot append lower layer"); So just for clarity in general, that was this one: Linux fedora 6.9.0-64.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Mon May 13 11:58:46 UTC 2024 x86_64 GNU/Linux Is mise le meas/Regards, Eric Curtin