Re: [PATCH 09/24] xfs: use direct calls for dquot IO completion

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, May 22, 2020 at 01:50:14PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Similar to inodes, we can call the dquot IO completion functions
> directly from the buffer completion code, removing another user of
> log item callbacks for IO completion processing.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks pretty straightforward.  I bet li_cb goes away soon?

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_buf_item.c | 18 +++++++++++++++++-
>  fs/xfs/xfs_dquot.c    | 27 +++++++++++++++++++++++----
>  fs/xfs/xfs_dquot.h    |  1 +
>  3 files changed, 41 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
> index e376f778bf57c..57e5d37f6852e 100644
> --- a/fs/xfs/xfs_buf_item.c
> +++ b/fs/xfs/xfs_buf_item.c
> @@ -15,6 +15,9 @@
>  #include "xfs_buf_item.h"
>  #include "xfs_inode.h"
>  #include "xfs_inode_item.h"
> +#include "xfs_quota.h"
> +#include "xfs_dquot_item.h"
> +#include "xfs_dquot.h"
>  #include "xfs_trans_priv.h"
>  #include "xfs_trace.h"
>  #include "xfs_log.h"
> @@ -1209,7 +1212,20 @@ void
>  xfs_buf_dquot_iodone(
>  	struct xfs_buf		*bp)
>  {
> -	xfs_buf_run_callbacks(bp);
> +	struct xfs_buf_log_item *blip = bp->b_log_item;
> +	struct xfs_log_item	*lip;
> +
> +	if (xfs_buf_had_callback_errors(bp))
> +		return;
> +
> +	/* a newly allocated dquot buffer might have a log item attached */
> +	if (blip) {
> +		lip = &blip->bli_item;
> +		lip->li_cb(bp, lip);
> +		bp->b_log_item = NULL;
> +	}
> +
> +	xfs_dquot_done(bp);
>  	xfs_buf_ioend_finish(bp);
>  }
>  
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index 25592b701db40..1d7f34a9bc989 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -1043,9 +1043,8 @@ xfs_qm_dqrele(
>   * from the AIL if it has not been re-logged, and unlocking the dquot's
>   * flush lock. This behavior is very similar to that of inodes..
>   */
> -STATIC void
> +static void
>  xfs_qm_dqflush_done(
> -	struct xfs_buf		*bp,
>  	struct xfs_log_item	*lip)
>  {
>  	struct xfs_dq_logitem	*qip = (struct xfs_dq_logitem *)lip;
> @@ -1086,6 +1085,27 @@ xfs_qm_dqflush_done(
>  	xfs_dqfunlock(dqp);
>  }
>  
> +void
> +xfs_dquot_done(
> +	struct xfs_buf		*bp)
> +{
> +	struct xfs_log_item	*lip;
> +
> +	while (!list_empty(&bp->b_li_list)) {
> +		lip = list_first_entry(&bp->b_li_list, struct xfs_log_item,
> +				       li_bio_list);
> +
> +		/*
> +		 * Remove the item from the list, so we don't have any
> +		 * confusion if the item is added to another buf.
> +		 * Don't touch the log item after calling its
> +		 * callback, because it could have freed itself.
> +		 */
> +		list_del_init(&lip->li_bio_list);
> +		xfs_qm_dqflush_done(lip);
> +	}
> +}
> +
>  /*
>   * Write a modified dquot to disk.
>   * The dquot must be locked and the flush lock too taken by caller.
> @@ -1175,8 +1195,7 @@ xfs_qm_dqflush(
>  	 * AIL and release the flush lock once the dquot is synced to disk.
>  	 */
>  	bp->b_flags |= _XBF_DQUOTS;
> -	xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
> -				  &dqp->q_logitem.qli_item);
> +	xfs_buf_attach_iodone(bp, NULL, &dqp->q_logitem.qli_item);
>  
>  	/*
>  	 * If the buffer is pinned then push on the log so we won't
> diff --git a/fs/xfs/xfs_dquot.h b/fs/xfs/xfs_dquot.h
> index fe3e46df604b4..f1924288986d3 100644
> --- a/fs/xfs/xfs_dquot.h
> +++ b/fs/xfs/xfs_dquot.h
> @@ -174,6 +174,7 @@ void		xfs_qm_dqput(struct xfs_dquot *dqp);
>  void		xfs_dqlock2(struct xfs_dquot *, struct xfs_dquot *);
>  
>  void		xfs_dquot_set_prealloc_limits(struct xfs_dquot *);
> +void		xfs_dquot_done(struct xfs_buf *);
>  
>  static inline struct xfs_dquot *xfs_qm_dqhold(struct xfs_dquot *dqp)
>  {
> -- 
> 2.26.2.761.g0e0b3e54be
>