Re: [PATCH 13/13] xfs: refactor dquot iteration

[Brian Foster <bfoster@redhat.com>]

On Sun, Apr 29, 2018 at 10:44:36PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Create a helper function to iterate all the dquots of a given type in
> the system, and refactor the dquot scrub to use it.  This will get more
> use in the quota repair code.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---

I get a compile warning from this patch:

fs/xfs//scrub/quota.c: In function ‘xfs_scrub_quota_item’:
fs/xfs//scrub/quota.c:115:3: warning: ‘offset’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With that fixed:

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/scrub/quota.c |   56 +++++++++++++++++++++++---------------------------
>  fs/xfs/xfs_dquot.c   |   32 +++++++++++++++++++++++++++++
>  fs/xfs/xfs_dquot.h   |    5 ++++
>  3 files changed, 63 insertions(+), 30 deletions(-)
> 
> 
> diff --git a/fs/xfs/scrub/quota.c b/fs/xfs/scrub/quota.c
> index 50415e8e5dd1..7bf102c290b7 100644
> --- a/fs/xfs/scrub/quota.c
> +++ b/fs/xfs/scrub/quota.c
> @@ -77,14 +77,20 @@ xfs_scrub_setup_quota(
>  
>  /* Quotas. */
>  
> +struct xfs_scrub_quota_info {
> +	struct xfs_scrub_context	*sc;
> +	xfs_dqid_t			last_id;
> +};
> +
>  /* Scrub the fields in an individual quota item. */
> -STATIC void
> +STATIC int
>  xfs_scrub_quota_item(
> -	struct xfs_scrub_context	*sc,
> -	uint				dqtype,
>  	struct xfs_dquot		*dq,
> -	xfs_dqid_t			id)
> +	uint				dqtype,
> +	void				*priv)
>  {
> +	struct xfs_scrub_quota_info	*sqi = priv;
> +	struct xfs_scrub_context	*sc = sqi->sc;
>  	struct xfs_mount		*mp = sc->mp;
>  	struct xfs_disk_dquot		*d = &dq->q_core;
>  	struct xfs_quotainfo		*qi = mp->m_quotainfo;
> @@ -99,17 +105,18 @@ xfs_scrub_quota_item(
>  	unsigned long long		icount;
>  	unsigned long long		rcount;
>  	xfs_ino_t			fs_icount;
> -
> -	offset = id / qi->qi_dqperchunk;
> +	xfs_dqid_t			id = be32_to_cpu(d->d_id);
>  
>  	/*
> -	 * We fed $id and DQNEXT into the xfs_qm_dqget call, which means
> -	 * that the actual dquot we got must either have the same id or
> -	 * the next higher id.
> +	 * Except for the root dquot, the actual dquot we got must either have
> +	 * the same or higher id as we saw before.
>  	 */
> -	if (id > be32_to_cpu(d->d_id))
> +	if (id && id <= sqi->last_id)
>  		xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
>  
> +	sqi->last_id = id;
> +	offset = id / qi->qi_dqperchunk;
> +
>  	/* Did we get the dquot type we wanted? */
>  	if (dqtype != (d->d_flags & XFS_DQ_ALLTYPES))
>  		xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
> @@ -183,6 +190,8 @@ xfs_scrub_quota_item(
>  		xfs_scrub_fblock_set_warning(sc, XFS_DATA_FORK, offset);
>  	if (id != 0 && rhard != 0 && rcount > rhard)
>  		xfs_scrub_fblock_set_warning(sc, XFS_DATA_FORK, offset);
> +
> +	return 0;
>  }
>  
>  /* Scrub all of a quota type's items. */
> @@ -191,13 +200,12 @@ xfs_scrub_quota(
>  	struct xfs_scrub_context	*sc)
>  {
>  	struct xfs_bmbt_irec		irec = { 0 };
> +	struct xfs_scrub_quota_info	sqi;
>  	struct xfs_mount		*mp = sc->mp;
>  	struct xfs_inode		*ip;
>  	struct xfs_quotainfo		*qi = mp->m_quotainfo;
> -	struct xfs_dquot		*dq;
>  	xfs_fileoff_t			max_dqid_off;
>  	xfs_fileoff_t			off = 0;
> -	xfs_dqid_t			id = 0;
>  	uint				dqtype;
>  	int				nimaps;
>  	int				error = 0;
> @@ -264,24 +272,12 @@ xfs_scrub_quota(
>  		goto out;
>  
>  	/* Check all the quota items. */
> -	while (id < ((xfs_dqid_t)-1ULL)) {
> -		if (xfs_scrub_should_terminate(sc, &error))
> -			break;
> -
> -		error = xfs_qm_dqget_next(mp, id, dqtype, &dq);
> -		if (error == -ENOENT)
> -			break;
> -		if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK,
> -				id * qi->qi_dqperchunk, &error))
> -			break;
> -
> -		xfs_scrub_quota_item(sc, dqtype, dq, id);
> -
> -		id = be32_to_cpu(dq->q_core.d_id) + 1;
> -		xfs_qm_dqput(dq);
> -		if (!id)
> -			break;
> -	}
> +	sqi.sc = sc;
> +	sqi.last_id = 0;
> +	error = xfs_qm_dqiterate(mp, dqtype, xfs_scrub_quota_item, &sqi);
> +	if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK,
> +			sqi.last_id * qi->qi_dqperchunk, &error))
> +		goto out;
>  
>  out:
>  	/* We set sc->ip earlier, so make sure we clear it now. */
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index 301a96d70785..6f7200f8f445 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -1213,3 +1213,35 @@ xfs_qm_exit(void)
>  	kmem_zone_destroy(xfs_qm_dqtrxzone);
>  	kmem_zone_destroy(xfs_qm_dqzone);
>  }
> +
> +/*
> + * Iterate every dquot of a particular type.  The caller must ensure that the
> + * particular quota type is active.  iter_fn can return negative error codes,
> + * or XFS_BTREE_QUERY_RANGE_ABORT to indicate that it wants to stop iterating.
> + */
> +int
> +xfs_qm_dqiterate(
> +	struct xfs_mount	*mp,
> +	uint			dqtype,
> +	xfs_qm_dqiterate_fn	iter_fn,
> +	void			*priv)
> +{
> +	struct xfs_dquot	*dq;
> +	xfs_dqid_t		id = 0;
> +	int			error;
> +
> +	do {
> +		error = xfs_qm_dqget_next(mp, id, dqtype, &dq);
> +		if (error == -ENOENT)
> +			return 0;
> +		if (error)
> +			return error;
> +
> +		error = iter_fn(dq, dqtype, priv);
> +		id = be32_to_cpu(dq->q_core.d_id);
> +		xfs_qm_dqput(dq);
> +		id++;
> +	} while (error == 0 && id != 0);
> +
> +	return error;
> +}
> diff --git a/fs/xfs/xfs_dquot.h b/fs/xfs/xfs_dquot.h
> index 6959f0135f36..417ac03b8d7b 100644
> --- a/fs/xfs/xfs_dquot.h
> +++ b/fs/xfs/xfs_dquot.h
> @@ -193,4 +193,9 @@ static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
>  	return dqp;
>  }
>  
> +typedef int (*xfs_qm_dqiterate_fn)(struct xfs_dquot *dq, uint dqtype,
> +		void *priv);
> +int xfs_qm_dqiterate(struct xfs_mount *mp, uint dqtype,
> +		xfs_qm_dqiterate_fn iter_fn, void *priv);
> +
>  #endif /* __XFS_DQUOT_H__ */
> 
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