[sheepdog] [PATCH v1 1/2] sheep: fix coredump of sheep daemon in disk mode

[Hitoshi Mitake]

At Wed, 11 Jun 2014 17:14:10 +0800,
Robin Dong wrote:
> 
> From: Robin Dong <sanbai at taobao.com>
> 
> In disk mode, we calculate number of md vnode by using "nr = disk_space / WEIGHT_MIN",
> when disk_space is smaller than WEIGHT_MIN (4G currently), the 'nr' will be zero.
> 
> Imaging a sheep daemon who has two data paths. One data path has 8GB space, but
> another data path has only 1GB space. The nr_disk is 2 and all the vnode in md.vroot
> is for the 8GB data path. Then the larger data path get a disk fail and be removed
> from md hashing ring, now the md.vroot has no vnode but nr_disk is 1. When the code
> routine comes to md_get_object_dir_nolock(), it will call oid_to_vdisk() and get NULL
> result which will make sheep daemon coredump.
> To fix this problem, we should calculate number of vnode by DIV_ROUND_UP in disk mode.
> 
> Signed-off-by: Robin Dong <sanbai at taobao.com>
> ---
>  include/sheep.h | 2 +-
>  sheep/md.c      | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)

This series looks good to me.
Reviewed-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>

Thanks,
Hitoshi

> 
> diff --git a/include/sheep.h b/include/sheep.h
> index 785883e..e062372 100644
> --- a/include/sheep.h
> +++ b/include/sheep.h
> @@ -216,7 +216,7 @@ node_disk_to_vnodes(const struct sd_node *n, struct rb_root *vroot)
>  		if (!n->disks[j].disk_id)
>  			continue;
>  		hval = fnv_64a_64(node_hval, n->disks[j].disk_id);
> -		disk_vnodes = n->disks[j].disk_space / WEIGHT_MIN;
> +		disk_vnodes = DIV_ROUND_UP(n->disks[j].disk_space, WEIGHT_MIN);
>  		total += disk_vnodes;
>  		for (int k = 0; k < disk_vnodes; k++) {
>  			hval = sd_hash_next(hval);
> diff --git a/sheep/md.c b/sheep/md.c
> index b95e032..7d45213 100644
> --- a/sheep/md.c
> +++ b/sheep/md.c
> @@ -77,7 +77,7 @@ static void create_vdisks(const struct disk *disk)
>  	if (is_cluster_diskmode(&sys->cinfo)) {
>  		node_hval = sd_hash(&n->nid, offsetof(typeof(n->nid), io_addr));
>  		hval = fnv_64a_64(node_hval, hval);
> -		nr = disk->space / WEIGHT_MIN;
> +		nr = DIV_ROUND_UP(disk->space, WEIGHT_MIN);
>  		if (0 == n->nid.port)
>  			return;
>  	} else
> @@ -110,7 +110,7 @@ static void remove_vdisks(const struct disk *disk)
>  	if (is_cluster_diskmode(&sys->cinfo)) {
>  		node_hval = sd_hash(&n->nid, offsetof(typeof(n->nid), io_addr));
>  		hval = fnv_64a_64(node_hval, hval);
> -		nr = disk->space / WEIGHT_MIN;
> +		nr = DIV_ROUND_UP(disk->space, WEIGHT_MIN);
>  	} else
>  		nr = vdisk_number(disk);
>  
> -- 
> 1.7.12.4
> 
> -- 
> sheepdog mailing list
> sheepdog at lists.wpkg.org
> http://lists.wpkg.org/mailman/listinfo/sheepdog