On Mon, Aug 24, 2020 at 09:54:29AM +1000, Dave Chinner wrote:
> On Thu, Aug 20, 2020 at 07:11:34PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >
> > Formally define the inode timestamp ranges that existing filesystems
> > support, and switch the vfs timetamp ranges to use it.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > ---
> > fs/xfs/libxfs/xfs_format.h | 19 +++++++++++++++++++
> > fs/xfs/xfs_ondisk.h | 12 ++++++++++++
> > fs/xfs/xfs_super.c | 5 +++--
> > 3 files changed, 34 insertions(+), 2 deletions(-)
> >
> >
> > diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> > index be86fa1a5556..b1b8a5c05cea 100644
> > --- a/fs/xfs/libxfs/xfs_format.h
> > +++ b/fs/xfs/libxfs/xfs_format.h
> > @@ -849,11 +849,30 @@ struct xfs_agfl {
> > ASSERT(xfs_daddr_to_agno(mp, d) == \
> > xfs_daddr_to_agno(mp, (d) + (len) - 1)))
> >
> > +/*
> > + * XFS Timestamps
> > + * ==============
> > + *
> > + * Inode timestamps consist of signed 32-bit counters for seconds and
> > + * nanoseconds; time zero is the Unix epoch, Jan 1 00:00:00 UTC 1970.
> > + */
> > typedef struct xfs_timestamp {
> > __be32 t_sec; /* timestamp seconds */
> > __be32 t_nsec; /* timestamp nanoseconds */
> > } xfs_timestamp_t;
> >
> > +/*
> > + * Smallest possible timestamp with traditional timestamps, which is
> > + * Dec 13 20:45:52 UTC 1901.
> > + */
> > +#define XFS_INO_TIME_MIN ((int64_t)S32_MIN)
> > +
> > +/*
> > + * Largest possible timestamp with traditional timestamps, which is
> > + * Jan 19 03:14:07 UTC 2038.
> > + */
> > +#define XFS_INO_TIME_MAX ((int64_t)S32_MAX)
>
> These are based on the Unix epoch. Can we call them something like
> XFS_INO_UNIX_TIME_{MIN,MAX} to indicate what epoch they reference?
I'll update the comment and name to make it clear that this is the Unix
epoch we're talking about.
> > /*
> > * On-disk inode structure.
> > *
> > diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> > index acb9b737fe6b..48a64fa49f91 100644
> > --- a/fs/xfs/xfs_ondisk.h
> > +++ b/fs/xfs/xfs_ondisk.h
> > @@ -15,6 +15,18 @@
> > "XFS: offsetof(" #structname ", " #member ") is wrong, " \
> > "expected " #off)
> >
> > +#define XFS_CHECK_VALUE(value, expected) \
> > + BUILD_BUG_ON_MSG((value) != (expected), \
> > + "XFS: value of " #value " is wrong, expected " #expected)
> > +
> > +static inline void __init
> > +xfs_check_limits(void)
> > +{
> > + /* make sure timestamp limits are correct */
> > + XFS_CHECK_VALUE(XFS_INO_TIME_MIN, -2147483648LL);
> > + XFS_CHECK_VALUE(XFS_INO_TIME_MAX, 2147483647LL);
> > +}
>
> Not sure this really gains us anything? All it does is check that
> S32_MIN/S32_MAX haven't changed value....
Will remove.
--D
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
