Re: [PATCH v27 02/15] xfs: don't commit the first deferred transaction without intents

[Chandan Babu R <chandan.babu@oracle.com>]

On 16 Feb 2022 at 07:07, Allison Henderson wrote:
> If the first operation in a string of defer ops has no intents,
> then there is no reason to commit it before running the first call
> to xfs_defer_finish_one(). This allows the defer ops to be used
> effectively for non-intent based operations without requiring an
> unnecessary extra transaction commit when first called.
>
> This fixes a regression in per-attribute modification transaction
> count when delayed attributes are not being used.
>

Looks good to me.

Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>

> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_defer.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
> index 6dac8d6b8c21..26680e9f50f5 100644
> --- a/fs/xfs/libxfs/xfs_defer.c
> +++ b/fs/xfs/libxfs/xfs_defer.c
> @@ -510,9 +510,16 @@ xfs_defer_finish_noroll(
>  		xfs_defer_create_intents(*tp);
>  		list_splice_init(&(*tp)->t_dfops, &dop_pending);
>  
> -		error = xfs_defer_trans_roll(tp);
> -		if (error)
> -			goto out_shutdown;
> +		/*
> +		 * We must ensure the transaction is clean before we try to finish
> +		 * deferred work by committing logged intent items and anything
> +		 * else that dirtied the transaction.
> +		 */
> +		if ((*tp)->t_flags & XFS_TRANS_DIRTY) {
> +			error = xfs_defer_trans_roll(tp);
> +			if (error)
> +				goto out_shutdown;
> +		}
>  
>  		/* Possibly relog intent items to keep the log moving. */
>  		error = xfs_defer_relog(tp, &dop_pending);


-- 
chandan