Re: [PATCH v15 07/22] xfs: Add helper xfs_attr_node_addname_find_attr

[Brian Foster <bfoster@redhat.com>]

On Thu, Feb 18, 2021 at 09:53:33AM -0700, Allison Henderson wrote:
> This patch separates the first half of xfs_attr_node_addname into a
> helper function xfs_attr_node_addname_find_attr.  It also replaces the
> restart goto with with an EAGAIN return code driven by a loop in the
> calling function.  This looks odd now, but will clean up nicly once we
> introduce the state machine.  It will also enable hoisting the last
> state out of xfs_attr_node_addname with out having to plumb in a "done"
> parameter to know if we need to move to the next state or not.
> 
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 80 ++++++++++++++++++++++++++++++------------------
>  1 file changed, 51 insertions(+), 29 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index bee8d3fb..4333b61 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
...
> @@ -941,6 +931,38 @@ xfs_attr_node_addname(
>  		args->rmtvaluelen = 0;
>  	}
>  
> +	return 0;
> +out:

Nit: can we call this label 'error' since it appears to be used when we
want to return the current retval as an operational error?

> +	if (*state)
> +		xfs_da_state_free(*state);
> +	return retval;
> +}
> +
> +/*
> + * Add a name to a Btree-format attribute list.
> + *
> + * This will involve walking down the Btree, and may involve splitting
> + * leaf nodes and even splitting intermediate nodes up to and including
> + * the root node (a special case of an intermediate node).
> + *
> + * "Remote" attribute values confuse the issue and atomic rename operations
> + * add a whole extra layer of confusion on top of that.
> + */
> +STATIC int
> +xfs_attr_node_addname(
> +	struct xfs_da_args	*args,
> +	struct xfs_da_state	*state)
> +{
> +	struct xfs_da_state_blk	*blk;
> +	struct xfs_inode	*dp;
> +	int			retval, error;
> +
> +	trace_xfs_attr_node_addname(args);

This moves the tracepoint into the looping sequence whereas previously
it would only execute once. I don't see a clean way to fix that with the
breakdown as of this patch, and it's not a huge deal, but it would be
nice to fix that before the end of the series if we haven't already.
Otherwise LGTM:

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

> +
> +	dp = args->dp;
> +	blk = &state->path.blk[state->path.active-1];
> +	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> +
>  	retval = xfs_attr3_leaf_add(blk->bp, state->args);
>  	if (retval == -ENOSPC) {
>  		if (state->path.active == 1) {
> @@ -966,7 +988,7 @@ xfs_attr_node_addname(
>  			if (error)
>  				goto out;
>  
> -			goto restart;
> +			return -EAGAIN;
>  		}
>  
>  		/*
> -- 
> 2.7.4
>