Re: [PATCH v21 13/13] xfs: Add helper function xfs_attr_leaf_addname

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Jul 07, 2021 at 03:21:11PM -0700, Allison Henderson wrote:
> This patch adds a helper function xfs_attr_leaf_addname.  While this
> does help to break down xfs_attr_set_iter, it does also hoist out some
> of the state management.  This patch has been moved to the end of the
> clean up series for further discussion.
> 
> Suggested-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 107 ++++++++++++++++++++++++++---------------------
>  fs/xfs/xfs_trace.h       |   1 +
>  2 files changed, 60 insertions(+), 48 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index cb7e689..80486b4 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -284,6 +284,64 @@ xfs_attr_sf_addname(
>  	return -EAGAIN;
>  }
>  
> +STATIC int
> +xfs_attr_leaf_addname(
> +	struct xfs_attr_item	*attr)
> +{
> +	struct xfs_da_args	*args = attr->xattri_da_args;
> +	struct xfs_buf		*leaf_bp = attr->xattri_leaf_bp;
> +	struct xfs_inode	*dp = args->dp;
> +	int			error;
> +
> +	if (xfs_attr_is_leaf(dp)) {
> +		error = xfs_attr_leaf_try_add(args, leaf_bp);
> +		if (error == -ENOSPC) {
> +			error = xfs_attr3_leaf_to_node(args);
> +			if (error)
> +				return error;
> +
> +			/*
> +			 * Finish any deferred work items and roll the
> +			 * transaction once more.  The goal here is to call
> +			 * node_addname with the inode and transaction in the
> +			 * same state (inode locked and joined, transaction
> +			 * clean) no matter how we got to this step.
> +			 *
> +			 * At this point, we are still in XFS_DAS_UNINIT, but
> +			 * when we come back, we'll be a node, so we'll fall
> +			 * down into the node handling code below
> +			 */
> +			trace_xfs_attr_set_iter_return(
> +				attr->xattri_dela_state, args->dp);
> +			return -EAGAIN;
> +		} else if (error) {

Silly nit: No need for else if, regular if works fine here.

Oh, hm, this is just a hoist patch, and we're not supposed to
hoist-and-mutate.  But this is a small change, so fmeh rules.

With that tidied,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> +			return error;
> +		}
> +
> +		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
> +	} else {
> +		error = xfs_attr_node_addname_find_attr(attr);
> +		if (error)
> +			return error;
> +
> +		error = xfs_attr_node_addname(attr);
> +		if (error)
> +			return error;
> +
> +		/*
> +		 * If addname was successful, and we dont need to alloc or
> +		 * remove anymore blks, we're done.
> +		 */
> +		if (!args->rmtblkno && !args->rmtblkno2)
> +			return error;
> +
> +		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
> +	}
> +
> +	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
> +	return -EAGAIN;
> +}
> +
>  /*
>   * Set the attribute specified in @args.
>   * This routine is meant to function as a delayed operation, and may return
> @@ -319,55 +377,8 @@ xfs_attr_set_iter(
>  			*leaf_bp = NULL;
>  		}
>  
> -		if (xfs_attr_is_leaf(dp)) {
> -			error = xfs_attr_leaf_try_add(args, *leaf_bp);
> -			if (error == -ENOSPC) {
> -				error = xfs_attr3_leaf_to_node(args);
> -				if (error)
> -					return error;
> -
> -				/*
> -				 * Finish any deferred work items and roll the
> -				 * transaction once more.  The goal here is to
> -				 * call node_addname with the inode and
> -				 * transaction in the same state (inode locked
> -				 * and joined, transaction clean) no matter how
> -				 * we got to this step.
> -				 *
> -				 * At this point, we are still in
> -				 * XFS_DAS_UNINIT, but when we come back, we'll
> -				 * be a node, so we'll fall down into the node
> -				 * handling code below
> -				 */
> -				trace_xfs_attr_set_iter_return(
> -					attr->xattri_dela_state, args->dp);
> -				return -EAGAIN;
> -			} else if (error) {
> -				return error;
> -			}
> -
> -			attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
> -		} else {
> -			error = xfs_attr_node_addname_find_attr(attr);
> -			if (error)
> -				return error;
> +		return xfs_attr_leaf_addname(attr);
>  
> -			error = xfs_attr_node_addname(attr);
> -			if (error)
> -				return error;
> -
> -			/*
> -			 * If addname was successful, and we dont need to alloc
> -			 * or remove anymore blks, we're done.
> -			 */
> -			if (!args->rmtblkno && !args->rmtblkno2)
> -				return error;
> -
> -			attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
> -		}
> -		trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
> -					       args->dp);
> -		return -EAGAIN;
>  	case XFS_DAS_FOUND_LBLK:
>  		/*
>  		 * If there was an out-of-line value, allocate the blocks we
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index f9840dd..cf8bd3a 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4008,6 +4008,7 @@ DEFINE_EVENT(xfs_das_state_class, name, \
>  	TP_ARGS(das, ip))
>  DEFINE_DAS_STATE_EVENT(xfs_attr_sf_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
> +DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_node_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_remove_iter_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);
> -- 
> 2.7.4
>