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?
> /*
> * 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....
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
