Re: [PATCH v2 2/2] xfs: fold xfs_create_tmpfile() into xfs_create()

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

> -     struct xfs_trans_res    tres;
> +     struct xfs_trans_res    *tres;
>       uint                    resblks;
>  
>       trace_xfs_create(dp, name);
> @@ -1181,14 +1181,21 @@ xfs_create(
>       if (is_dir) {
>               rdev = 0;
>               resblks = XFS_MKDIR_SPACE_RES(mp, name->len);
> -             tres.tr_logres = M_RES(mp)->tr_mkdir.tr_logres;
> -             tres.tr_logcount = XFS_MKDIR_LOG_COUNT;
> +             tres = &M_RES(mp)->tr_mkdir;

The (nice) reservation cleanup should be a patch of it's own. 

> +     } else {
> +             /*
> +              * If we don't have a name, we're in the ->tmpfile() path. We
> +              * have a unique transaction here since we modify the unlinked
> +              * list rather than create a directory entry.
> +              */

How is that transaction more "uniqueue" than the others?  Seems like
this comment generally doesn't add a whole lot of value.

> +     if (name) {
> +             xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
> +             unlock_dp_on_error = true;
> +
> +             error = xfs_dir_canenter(tp, dp, name, resblks);
> +             if (error)
> +                     goto out_trans_cancel;
> +     }

So we get another special case in this function.  Can't say I like that
too much, on the other hand I don't really like the duplicate code
either.  So I'm not excited about this, but also not strongly against it.