On Mon, Jun 01, 2020 at 05:06:36PM -0500, Eric Sandeen wrote:
> On 6/1/20 4:21 PM, Dave Chinner wrote:
> > The user was not responsible for this mess (combination of missing
> > validation in XFS code and bad storage firmware providing garbage)
> > so we should not put them on the hook for fixing it. We can do it
> > easily and without needing user intervention and so that's what we
> > should do.
>
> FWIW, I have a working xfs_repair that fixes bad geometry as well,
> I ... guess that's probably still useful?
Yes, repair should definitely be proactive on this.
> It was doing similar things to what you suggested, though I wasn't
> rounding swidth up, I was setting it equal to sunit. *shrug* rounding
> up is maybe better; the problematic devices usually have width < unit
> so rounding up will be the same as setting equal :)
Yup, that's exactly why I suggested rounding up :)
> phase1()
>
> + /*
> + * Now see if there's a problem with the stripe width; if it's bad,
> + * we just set it equal to the stripe unit as a harmless alternative.
> + */
> + if (xfs_sb_version_hasdalign(sb)) {
> + if ((sb->sb_unit && !sb->sb_width) ||
> + (sb->sb_width && sb->sb_unit && sb->sb_width % sb->sb_unit)) {
> + sb->sb_width = sb->sb_unit;
> + primary_sb_modified = 1;
> + geometry_modified = 1;
> + do_warn(
> +_("superblock has a bad stripe width, resetting to %d\n"),
> + sb->sb_width);
> + }
> + }
>
> I also had to more or less ignore bad swidths throughout repair (and in
> xfs_validate_sb_common IIRC) to be able to get this far. If repair thinks
> a superblock is bad, it goes looking for otheres to replace it and if the
> bad geometry came from the device, they are all equally "bad..."
Yeah. Which leads me to ask: should the kernel be updating the
secondary superblocks when it finds bad geometry in the primary, or
overwrites the geometry with user supplied info?
(I have a vague recollection of being asked something about this on
IRC and me muttering something about CXFS only trashing the primary
superblock...)
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
