[Cluster-devel] [PATCH] libgfs2: Return the rgrp count in lgfs2_rgrps_plan()

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> lgfs2_rgrps_plan() previously returned one of the rgrp sizes
> specifically so that gfs2_grow could check it. This check was also done
> inside the function so the return value would always be 0 when the rgrp
> size was too small anyway (really this means that there's not enough
> space in which to place sensibly sized rgrps). As returning 0 is
> sufficient to pass back the same information, we can return the resource
> group count from lgfs2_rgrps_plan() instead, as that is a more useful
> value in general.
> 
> Signed-off-by: Andrew Price <anprice@redhat.com>
> ---
>  gfs2/libgfs2/rgrp.c   | 7 +++----
>  gfs2/mkfs/main_grow.c | 8 +++-----
>  2 files changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/gfs2/libgfs2/rgrp.c b/gfs2/libgfs2/rgrp.c
> index cf4385a..b14d210 100644
> --- a/gfs2/libgfs2/rgrp.c
> +++ b/gfs2/libgfs2/rgrp.c
> @@ -302,8 +302,8 @@ uint32_t lgfs2_rgrp_align_len(const lgfs2_rgrps_t rgs,
> uint32_t len)
>   * rgs: The resource groups descriptor
>   * space: The number of remaining blocks to be allocated
>   * tgtsize: The target resource group size in blocks
> - * Returns the larger of the calculated resource group sizes, in blocks, or
> 0
> - * if the smaller would be less than GFS2_MIN_RGSIZE.
> + * Returns the number of resource groups planned to fit in the given space,
> or
> + * 0 if the smallest resource group would be smaller than GFS2_MIN_RGSIZE.
>   */
>  uint32_t lgfs2_rgrps_plan(const lgfs2_rgrps_t rgs, uint64_t space, uint32_t
>  tgtsize)
>  {
> @@ -352,11 +352,10 @@ uint32_t lgfs2_rgrps_plan(const lgfs2_rgrps_t rgs,
> uint64_t space, uint32_t tgts
>  	/* Once we've reached this point,
>  	   (plan[0].num * plan[0].len) + (plan[1].num * plan[1].len)
>  	   will be less than one adjustment smaller than 'space'.  */
> -
>  	if (rgs->plan[0].len < minlen)
>  		return 0;
>  
> -	return rgs->plan[0].len;
> +	return rgs->plan[0].num + rgs->plan[1].num;

Hi Andy,

Does this all work with a tiny file system that only has one resource group?
I remember trying to code similar things and Abhi kept having to fix it
because of problems with single-rgrp file systems. Bear in mind, I haven't
looked at the rest of this function in detail, so I'm speaking somewhat out
of ignorance.

Regards,

Bob Peterson
Red Hat File Systems