[oe] udev auto-mount not doing fsck

[Brian Hutchinson]

On Thu, Apr 10, 2014 at 2:00 PM, Brian Hutchinson <b.hutchman at gmail.com>wrote:

> On Thu, Apr 10, 2014 at 12:56 PM, Denys Dmytriyenko <denis at denix.org>wrote:
>
>> Brian,
>>
>> Be careful, with your eUSB storage device cold-plugged (available on boot)
>> you may run into a race condition, if you initially mount your rootfs in
>> read-only mode and then re-mount in read-write mode during boot. One of
>> the
>> proposed solutions:
>>
>> http://thread.gmane.org/gmane.comp.handhelds.openembedded.core/50124
>>
>> --
>> Denys
>> --
>> _______________________________________________
>> Openembedded-devel mailing list
>> Openembedded-devel at lists.openembedded.org
>> http://lists.openembedded.org/mailman/listinfo/openembedded-devel
>>
>
> At the moment the rootfs is rw in NOR.  In the future I plan for it to be
> squashfs (ro) with a union overlay that is rw ubifs for persistent stuff.
> This is to help protect the rootfs from getting corrupted or accidentally
> hosed up during an update etc.
>
> So I could see where the race condition you mentioned could happen maybe
> in that case but I'm not quite following (yet) how it could happen
> currently in rw mode.  I guess you're saying there is a point where the
> rootfs could be ro and so the udev rule has no mount point to hang the eUSB
> on ... If I'm picking up what you're laying down ('if' being the key word
> :) )
>
> This eUSB is intended to stay on the board at all times and not be hot
> plugged ... but it is socketed (but board is buried in an enclosure) so it
> could be replaced if needed by a technician.
>
> I'll study that patch you mentioned more when I get some time (in SCRUM
> meeting at the time ... joy).
>
> Regards,
>
> Brian
>
>
Hi Denys,

OK, I see what you are talking about now.  In my /etc/fstab I do have sixth
column of root set to 1 so if I'm understanding things right
/etc/rcS.d/S10checkroot.sh could be off checking root mounted ro while udev
sees my eUSB and is in the process of doing RUN mount.sh and trying to
mount /media/sda1 (in my case) before rootfs is remounted back rw.

Ah, I also see that /forcefsck only checks root ... for some reason I was
thinking it would cause fsck to look at fstab and scan all filesystems in
order of sixth column but that doesn't appear to be the case ... so that
answers one of my questions.

I still don't know why my eUSB wasn't checked when I stubbed out udev
automount script and instead added it to fstab with a 2 in the sixth column
... I thought that should of worked but it didn't.  It did in fact mount my
eUSB but it did not check it.  The answer to that too is probably in one of
these rcS scripts that I just haven't seen yet.

So the patch you mentioned is making more sense now.

Let me know if I'm tracking now or still off in the weeds.

Regards,

Brian