[systemd-devel] [PATCH] fstab-generator: local-fs.target waits for nofail mounts

[Vivek Goyal]

On Thu, Apr 10, 2014 at 06:38:59AM +0400, Andrey Borzenkov wrote:

[..]
> > So with nofail opion for rootfs we should have following situation.
> > 
> > - sysroot.mount
> > 	Before=initrd-root-fs.target
> > - initrd-root-fs.target
> > 	Requires=sysroot.mount
> > 	OnFailure=emergency.target
> > - initrd.target
> > 	Wants=initrd-root-fs.target
> > 	OnFailure=emergency.target
> > - dracut-pre-pivot.service
> > 	After=initrd.target sysroot.mount
> > 
> > Now let us say sysroot.mount failed activation because root device did not
> > show up. We waited for certain time interval, then time out. Now what will
> > happen to initrd-root-fs.target and initrd.target states.
> > 
> 
> Assuming initrd-root-fs.target Requires sysroot.mounts it enters Failed
> state and systemd effectively executes analog of "systemctl start
> emergency.target". What happens after that is defined entirely by what
> emergency.target pulls in. 
> 
> initrd.target in your example does not depend on sysroot.mount in any
> way so unless there are further indirect dependencies it actually
> should be reached at this point.

initrd.target Wants initrd-root-fs.target which inturn depends on
sysroot.mount. systemd automatically generates a Requires=sysroot.mount
in initrd-root-fs.target.

So if sysroot.mount fails, that should start emergency.target as
initrd-root-fs.target will fail. 

As initrd.target has Wants=initrd-root-fs.target, and
initrd-root-fs.target activation has failed. So does that mean that
initrd.target will reach the failed state too and we will try to
launch emergency.target.

What will happen to dracut-pre-pivot.service. It is supposed to run
after intird.target has reached. Now initrd.target has failed activation.
Will dracut-pre-pivot.service be activated?

Thanks
Vivek