Re: [PATCH v2] xfs: introduce xfs_validate_stripe_geometry()

Gao Xiang
2020-10-13T14:11:56Z

On Tue, Oct 13, 2020 at 10:07:26AM -0400, Brian Foster wrote:
> On Tue, Oct 13, 2020 at 09:55:37PM +0800, Gao Xiang wrote:
> > Hi Brian,
> >
> > On Tue, Oct 13, 2020 at 09:44:11AM -0400, Brian Foster wrote:
> > > On Tue, Oct 13, 2020 at 11:48:53AM +0800, Gao Xiang wrote:
> > > > Introduce a common helper to consolidate stripe validation process.
> > > > Also make kernel code xfs_validate_sb_common() use it first.
> > > >
> > > > Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> > > > ---
> > > > v1: https://lore.kernel.org/r/20201009050546.32174-1-hsiangkao@redhat.com
> > > >
> > > > changes since v1:
> > > > - rename the helper to xfs_validate_stripe_geometry() (Brian);
> > > > - drop a new added trailing newline in xfs_sb.c (Brian);
> > > > - add a "bool silent" argument to avoid too many error messages (Brian).
> > > >
> > > > fs/xfs/libxfs/xfs_sb.c | 70 +++++++++++++++++++++++++++++++++++-------
> > > > fs/xfs/libxfs/xfs_sb.h | 3 ++
> > > > 2 files changed, 62 insertions(+), 11 deletions(-)
> > > >
> > > > diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> > > > index 5aeafa59ed27..9178715ded45 100644
> > > > --- a/fs/xfs/libxfs/xfs_sb.c
> > > > +++ b/fs/xfs/libxfs/xfs_sb.c
> > > > @@ -360,21 +360,18 @@ xfs_validate_sb_common(
> > > > }
> > > > }
> > > >
> > > > - if (sbp->sb_unit) {
> > > > - if (!xfs_sb_version_hasdalign(sbp) ||
> > > > - sbp->sb_unit > sbp->sb_width ||
> > > > - (sbp->sb_width % sbp->sb_unit) != 0) {
> > > > - xfs_notice(mp, "SB stripe unit sanity check failed");
> > > > - return -EFSCORRUPTED;
> > > > - }
> > > > - } else if (xfs_sb_version_hasdalign(sbp)) {
> > > > + /*
> > > > + * Either (sb_unit and !hasdalign) or (!sb_unit and hasdalign)
> > > > + * would imply the image is corrupted.
> > > > + */
> > > > + if (!sbp->sb_unit ^ !xfs_sb_version_hasdalign(sbp)) {
> > >
> > > This can be simplified to drop the negations (!), right?
> >
> > Thanks for the suggestion.
> >
> > yet nope, honestly I don't think so, the reason is that sbp->sb_unit is
> > an integer here rather than a boolean, so negations cannot be
> > simplified and I think it's simpliest now... (some boolean algebra...)
> >
>
> Oh, right. So you'd actually need something like (!!sunit ^ hasdalign())
> to avoid the bit operation.

Agree, that expression looks better <nod>
I will switch to it then. Thanks!

Thanks,
Gao Xiang

>
> Brian