[Cluster-devel] [GFS2 PATCH 1/4] gfs2: check quota for blocks we're about to allocate

[Andrew Price <anprice@redhat.com>]

Hi Abhi,

On 12/02/15 16:54, Abhi Das wrote:
> This patch allows gfs2_quota_check() to take an extra argument
> called 'exp_change'. Prior to any allocation, gfs2_quota_check()
> or gfs2_quota_lock_check() is called with exp_change containing
> the number of blocks we expect to allocate in this operation.
> gfs2_quota_check() will add this number to the current usage and
> check the sum against the quota warns and limits and fail the
> operation if necessary.
>
<snip>
> -int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid)
> +int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid, s64 exp_change)
>   {
>   	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
>   	struct gfs2_quota_data *qd;
> @@ -1116,7 +1116,7 @@ int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid)
>
>   		value = (s64)be64_to_cpu(qd->qd_qb.qb_value);
>   		spin_lock(&qd_lock);
> -		value += qd->qd_change;
> +		value += qd->qd_change + exp_change;

So I guess I don't understand why we need both qd_change and exp_change 
now. What sets qd_change, and why can't it be accurate (i.e. equal to 
exp_change) when we need it to be?

Andy