Re: [PATCH 09/11] xfs: widen ondisk quota expiration timestamps to handle y2038+

[Allison Collins <allison.henderson@oracle.com>]

On 8/26/20 3:05 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Enable the bigtime feature for quota timers.  We decrease the accuracy
> of the timers to ~4s in exchange for being able to set timers up to the
> bigtime maximum.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
ok, looks ok to me
Reviewed-by: Allison Collins <allison.henderson@oracle.com>

> ---
>   fs/xfs/libxfs/xfs_dquot_buf.c  |   21 +++++++++++++++--
>   fs/xfs/libxfs/xfs_format.h     |   50 +++++++++++++++++++++++++++++++++++++++-
>   fs/xfs/libxfs/xfs_quota_defs.h |    3 ++
>   fs/xfs/xfs_dquot.c             |   10 ++++++++
>   fs/xfs/xfs_ondisk.h            |    5 ++++
>   fs/xfs/xfs_qm.c                |   13 +++++++++-
>   fs/xfs/xfs_trans_dquot.c       |    6 +++++
>   7 files changed, 102 insertions(+), 6 deletions(-)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_dquot_buf.c b/fs/xfs/libxfs/xfs_dquot_buf.c
> index cf85bad8a894..6766417d5ba4 100644
> --- a/fs/xfs/libxfs/xfs_dquot_buf.c
> +++ b/fs/xfs/libxfs/xfs_dquot_buf.c
> @@ -69,6 +69,13 @@ xfs_dquot_verify(
>   	    ddq_type != XFS_DQTYPE_GROUP)
>   		return __this_address;
>   
> +	if ((ddq->d_type & XFS_DQTYPE_BIGTIME) &&
> +	    !xfs_sb_version_hasbigtime(&mp->m_sb))
> +		return __this_address;
> +
> +	if ((ddq->d_type & XFS_DQTYPE_BIGTIME) && !ddq->d_id)
> +		return __this_address;
> +
>   	if (id != -1 && id != be32_to_cpu(ddq->d_id))
>   		return __this_address;
>   
> @@ -295,7 +302,12 @@ xfs_dquot_from_disk_ts(
>   	struct xfs_disk_dquot	*ddq,
>   	__be32			dtimer)
>   {
> -	return be32_to_cpu(dtimer);
> +	uint32_t		t = be32_to_cpu(dtimer);
> +
> +	if (t != 0 && (ddq->d_type & XFS_DQTYPE_BIGTIME))
> +		return xfs_dq_bigtime_to_unix(t);
> +
> +	return t;
>   }
>   
>   /* Convert an incore timer value into an on-disk timer value. */
> @@ -304,5 +316,10 @@ xfs_dquot_to_disk_ts(
>   	struct xfs_dquot	*dqp,
>   	time64_t		timer)
>   {
> -	return cpu_to_be32(timer);
> +	uint32_t		t = timer;
> +
> +	if (timer != 0 && (dqp->q_type & XFS_DQTYPE_BIGTIME))
> +		t = xfs_dq_unix_to_bigtime(timer);
> +
> +	return cpu_to_be32(t);
>   }
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index 972c740aaf7b..9cf84b57e2ce 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -1257,13 +1257,15 @@ static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
>   #define XFS_DQTYPE_USER		0x01		/* user dquot record */
>   #define XFS_DQTYPE_PROJ		0x02		/* project dquot record */
>   #define XFS_DQTYPE_GROUP	0x04		/* group dquot record */
> +#define XFS_DQTYPE_BIGTIME	0x08		/* large expiry timestamps */
>   
>   /* bitmask to determine if this is a user/group/project dquot */
>   #define XFS_DQTYPE_REC_MASK	(XFS_DQTYPE_USER | \
>   				 XFS_DQTYPE_PROJ | \
>   				 XFS_DQTYPE_GROUP)
>   
> -#define XFS_DQTYPE_ANY		(XFS_DQTYPE_REC_MASK)
> +#define XFS_DQTYPE_ANY		(XFS_DQTYPE_REC_MASK | \
> +				 XFS_DQTYPE_BIGTIME)
>   
>   /*
>    * XFS Quota Timers
> @@ -1276,6 +1278,10 @@ static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
>    * ondisk min and max defined here can be used directly to constrain the incore
>    * quota expiration timestamps on a Unix system.
>    *
> + * When bigtime is enabled, we trade two bits of precision to expand the
> + * expiration timeout range to match that of big inode timestamps.  The min and
> + * max recorded here are the on-disk limits, not a Unix timestamp.
> + *
>    * The grace period for each quota type is stored in the root dquot (id = 0)
>    * and is applied to a non-root dquot when it exceeds the soft or hard limits.
>    * The length of quota grace periods are unsigned 32-bit quantities measured in
> @@ -1294,6 +1300,48 @@ static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
>    */
>   #define XFS_DQ_LEGACY_EXPIRY_MAX	((int64_t)U32_MAX)
>   
> +/*
> + * Smallest possible ondisk quota expiration value with bigtime timestamps.
> + * This corresponds (after conversion to a Unix timestamp) with the incore
> + * expiration of Jan  1 00:00:04 UTC 1970.
> + */
> +#define XFS_DQ_BIGTIME_EXPIRY_MIN	(XFS_DQ_LEGACY_EXPIRY_MIN)
> +
> +/*
> + * Largest supported ondisk quota expiration value with bigtime timestamps.
> + * This corresponds (after conversion to a Unix timestamp) with an incore
> + * expiration of Jul  2 20:20:24 UTC 2486.
> + *
> + * The ondisk field supports values up to -1U, which corresponds to an incore
> + * expiration in 2514.  This is beyond the maximum the bigtime inode timestamp,
> + * so we cap the maximum bigtime quota expiration to the max inode timestamp.
> + */
> +#define XFS_DQ_BIGTIME_EXPIRY_MAX	((int64_t)4074815106U)
> +
> +/*
> + * The following conversion factors assist in converting a quota expiration
> + * timestamp between the incore and ondisk formats.
> + */
> +#define XFS_DQ_BIGTIME_SHIFT	(2)
> +#define XFS_DQ_BIGTIME_SLACK	((int64_t)(1ULL << XFS_DQ_BIGTIME_SHIFT) - 1)
> +
> +/* Convert an incore quota expiration timestamp to an ondisk bigtime value. */
> +static inline uint32_t xfs_dq_unix_to_bigtime(time64_t unix_seconds)
> +{
> +	/*
> +	 * Round the expiration timestamp up to the nearest bigtime timestamp
> +	 * that we can store, to give users the most time to fix problems.
> +	 */
> +	return ((uint64_t)unix_seconds + XFS_DQ_BIGTIME_SLACK) >>
> +			XFS_DQ_BIGTIME_SHIFT;
> +}
> +
> +/* Convert an ondisk bigtime quota expiration value to an incore timestamp. */
> +static inline time64_t xfs_dq_bigtime_to_unix(uint32_t ondisk_seconds)
> +{
> +	return (time64_t)ondisk_seconds << XFS_DQ_BIGTIME_SHIFT;
> +}
> +
>   /*
>    * Default quota grace periods, ranging from zero (use the compiled defaults)
>    * to ~136 years.  These are applied to a non-root dquot that has exceeded
> diff --git a/fs/xfs/libxfs/xfs_quota_defs.h b/fs/xfs/libxfs/xfs_quota_defs.h
> index 9a99910d857e..0f0af4e35032 100644
> --- a/fs/xfs/libxfs/xfs_quota_defs.h
> +++ b/fs/xfs/libxfs/xfs_quota_defs.h
> @@ -23,7 +23,8 @@ typedef uint8_t		xfs_dqtype_t;
>   #define XFS_DQTYPE_STRINGS \
>   	{ XFS_DQTYPE_USER,	"USER" }, \
>   	{ XFS_DQTYPE_PROJ,	"PROJ" }, \
> -	{ XFS_DQTYPE_GROUP,	"GROUP" }
> +	{ XFS_DQTYPE_GROUP,	"GROUP" }, \
> +	{ XFS_DQTYPE_BIGTIME,	"BIGTIME" }
>   
>   /*
>    * flags for q_flags field in the dquot.
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index 59c03e973741..3f9e11c3df1e 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -223,6 +223,8 @@ xfs_qm_init_dquot_blk(
>   		d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
>   		d->dd_diskdq.d_id = cpu_to_be32(curid);
>   		d->dd_diskdq.d_type = type;
> +		if (curid > 0 && xfs_sb_version_hasbigtime(&mp->m_sb))
> +			d->dd_diskdq.d_type |= XFS_DQTYPE_BIGTIME;
>   		if (xfs_sb_version_hascrc(&mp->m_sb)) {
>   			uuid_copy(&d->dd_uuid, &mp->m_sb.sb_meta_uuid);
>   			xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
> @@ -1167,6 +1169,14 @@ xfs_qm_dqflush_check(
>   	    !dqp->q_rtb.timer)
>   		return __this_address;
>   
> +	/* bigtime flag should never be set on root dquots */
> +	if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
> +		if (!xfs_sb_version_hasbigtime(&dqp->q_mount->m_sb))
> +			return __this_address;
> +		if (dqp->q_id == 0)
> +			return __this_address;
> +	}
> +
>   	return NULL;
>   }
>   
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index 52db8743def1..a13686ce0626 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -165,6 +165,11 @@ xfs_check_ondisk_structs(void)
>   			XFS_LEGACY_TIME_MIN);
>   	XFS_CHECK_VALUE(XFS_BIGTIME_TIME_MAX - XFS_BIGTIME_EPOCH_OFFSET,
>   			16299260424LL);
> +
> +	/* Do the same with the incore quota expiration range. */
> +	XFS_CHECK_VALUE(XFS_DQ_BIGTIME_EXPIRY_MIN << XFS_DQ_BIGTIME_SHIFT, 4);
> +	XFS_CHECK_VALUE(XFS_DQ_BIGTIME_EXPIRY_MAX << XFS_DQ_BIGTIME_SHIFT,
> +			16299260424LL);
>   }
>   
>   #endif /* __XFS_ONDISK_H */
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index b83a12ecfc35..259588a4227d 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -661,8 +661,15 @@ xfs_qm_init_quotainfo(
>   	/* Precalc some constants */
>   	qinf->qi_dqchunklen = XFS_FSB_TO_BB(mp, XFS_DQUOT_CLUSTER_SIZE_FSB);
>   	qinf->qi_dqperchunk = xfs_calc_dquots_per_chunk(qinf->qi_dqchunklen);
> -	qinf->qi_expiry_min = XFS_DQ_LEGACY_EXPIRY_MIN;
> -	qinf->qi_expiry_max = XFS_DQ_LEGACY_EXPIRY_MAX;
> +	if (xfs_sb_version_hasbigtime(&mp->m_sb)) {
> +		qinf->qi_expiry_min =
> +			xfs_dq_bigtime_to_unix(XFS_DQ_BIGTIME_EXPIRY_MIN);
> +		qinf->qi_expiry_max =
> +			xfs_dq_bigtime_to_unix(XFS_DQ_BIGTIME_EXPIRY_MAX);
> +	} else {
> +		qinf->qi_expiry_min = XFS_DQ_LEGACY_EXPIRY_MIN;
> +		qinf->qi_expiry_max = XFS_DQ_LEGACY_EXPIRY_MAX;
> +	}
>   
>   	mp->m_qflags |= (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_CHKD);
>   
> @@ -881,6 +888,8 @@ xfs_qm_reset_dqcounts(
>   			ddq->d_bwarns = 0;
>   			ddq->d_iwarns = 0;
>   			ddq->d_rtbwarns = 0;
> +			if (xfs_sb_version_hasbigtime(&mp->m_sb))
> +				ddq->d_type |= XFS_DQTYPE_BIGTIME;
>   		}
>   
>   		if (xfs_sb_version_hascrc(&mp->m_sb)) {
> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
> index c6ba7ef18e06..133fc6fc3edd 100644
> --- a/fs/xfs/xfs_trans_dquot.c
> +++ b/fs/xfs/xfs_trans_dquot.c
> @@ -55,6 +55,12 @@ xfs_trans_log_dquot(
>   {
>   	ASSERT(XFS_DQ_IS_LOCKED(dqp));
>   
> +	/* Upgrade the dquot to bigtime format if possible. */
> +	if (dqp->q_id != 0 &&
> +	    xfs_sb_version_hasbigtime(&tp->t_mountp->m_sb) &&
> +	    !(dqp->q_type & XFS_DQTYPE_BIGTIME))
> +		dqp->q_type |= XFS_DQTYPE_BIGTIME;
> +
>   	tp->t_flags |= XFS_TRANS_DIRTY;
>   	set_bit(XFS_LI_DIRTY, &dqp->q_logitem.qli_item.li_flags);
>   }
>