Re: [PATCH 08/11] xfs: widen ondisk timestamps to deal with y2038 problem

Amir Goldstein
2020-08-18T12:54:12Z

On Tue, Aug 18, 2020 at 3:00 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Tue, Aug 18, 2020 at 1:57 AM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> >
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > Redesign the ondisk timestamps to be a simple unsigned 64-bit counter of
> > nanoseconds since 14 Dec 1901 (i.e. the minimum time in the 32-bit unix
> > time epoch). This enables us to handle dates up to 2486, which solves
> > the y2038 problem.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> ...
>
> > diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
> > index 9f036053fdb7..b354825f4e51 100644
> > --- a/fs/xfs/scrub/inode.c
> > +++ b/fs/xfs/scrub/inode.c
> > @@ -190,6 +190,11 @@ xchk_inode_flags2(
> > if ((flags2 & XFS_DIFLAG2_DAX) && (flags2 & XFS_DIFLAG2_REFLINK))
> > goto bad;
> >
> > + /* the incore bigtime iflag always follows the feature flag */
> > + if (!!xfs_sb_version_hasbigtime(&mp->m_sb) ^
> > + !!(flags2 & XFS_DIFLAG2_BIGTIME))
> > + goto bad;
> > +
>
> Seems like flags2 are not the incore iflags and that the dinode iflags
> can very well
> have no bigtime on fs with bigtime support:
>
> xchk_dinode(...
> ...
> flags2 = be64_to_cpu(dip->di_flags2);
>
> What am I missing?
>

Another question. Do we need to worry about xfs_reinit_inode()?
It seems not because incore inode should already have the correct bigtime
flag. Right? But by same logic, xfs_ifree() should already have the correct
bigtime flag as well, so we don't need to set the flag, maybe assert the flag?

Thanks,
Amir.