Re: [PATCH v3 0/8] Nvram-to-pstore

[Aruna Balakrishnaiah]

On Wednesday 05 June 2013 03:13 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2013-06-05 at 14:30 +0530, Aruna Balakrishnaiah wrote:
> > Hi Ben,
> >
> > On Saturday 01 June 2013 10:55 AM, Benjamin Herrenschmidt wrote:
> > > Another question...
> > >
> > > Should the core pstore fail to unlink partitions that don't have
> > > an ->erase callback ? IE. Why would you let anyone erase the OFW
> > > common partition for example ? That means that userspace tools
> > > can no longer manipulate it but we certainly don't want to remove
> > > it from the nvram itself.
> > Since I do not have a callback for erase in nvram, pstore
> > simply unlinks the file and will not delete the partition.
> Right. My point is that it should probably refuse to unlink the file
> too. What's the point in letting the user remove the file, potentially
> making tools not working anymore, without any way to bring it back other
> than a reboot ?
>
> unlink makes sense if it also removes the partition. If it doesn't it
> should just fail.

Right, makes sense. Will create a patch to fix it in pstore.

> > > That leads to a deeper concern. Looking at how efi-pstore works,
> > > it looks like they create a file for each var.
> > >
> > > This looks like something valuable we could do for something like
> > > the common partition since typically it's made of name,value pairs.
> > >
> > > However, pstore is a flat space, while we have patitions which
> > > themselves can be organized in name,value pairs (some at least)
> > >
> > > I wonder if it's time to introduce pstore directories... Or do
> > > we stick to our special tools to interpret/change the name,value
> > > pairs ?
> > Since pstore infrastructure creates the file in read-only mode
> > creating files for name, value pairs will not be useful to us.
> > So for now, we need to stick to our tools to interpret/change
> > the name,value pairs.
> >
> > And also, pstore filenames are controlled by pstore infrastructure
> > so that would need quite some changes in the pstore infrastructure.
> >
> > I think for now it would be better to dump the contents of common
> > partition as it is.
> Ok.
>
> > > Also do we want to add an ability to resize partitions ? Possibly
> > > based on how much is written to them ?
> > Yes it will be good to that.
> >
> > If your fine with patchset apart from the filenames of-config and common
> > partitions. I will post the next version of it with powerpc prefix.
> Yes, I'm ok with it.
>
> Cheers,
> Ben.
>
> > > Cheers,
> > > Ben.
> > >
> > >
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