[Cluster-devel] [GFS2 PATCH 3/3] gfs2: allow fallocate to max out quotas/fs efficiently

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

On 16/02/15 17:59, Abhi Das wrote:
> We can quickly get an estimate of how many more blocks are
> available for allocation restricted by quota and fs size
> respectively using the ap->allowed field in the gfs2_alloc_parms
> structure. gfs2_quota_check() and gfs2_inplace_reserve() provide
> these values.
>
> By re-trying to allocate what's available instead of guessing, we
> can max out quotas or the filesystem efficiently.
>
> Bear in mind that this applies only when the requested fallocate
> operation would otherwise error out with -EDQUOT or -ENOSPC without
> utilizing all the blocks that might still be available.
>
> Signed-off-by: Abhi Das <adas@redhat.com>
> ---
>   fs/gfs2/file.c | 18 +++++++++++-------
>   1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index 2ea420a..57129fa 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -829,20 +829,24 @@ static long __gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t
>   			continue;
>   		}
>   		ap.target = bytes >> sdp->sd_sb.sb_bsize_shift;
> +	quota_retry:
>   		error = gfs2_quota_lock_check(ip, &ap);
> -		if (error)
> +		if (error) {
> +			if (error == -EDQUOT && ap.allowed) {
> +				bytes = ap.allowed << sdp->sd_sb.sb_bsize_shift;
> +				ap.target = ap.allowed;
> +				goto quota_retry;
> +			}
>   			return error;
Do you really need to loop here if -EDQUOT is returned and ap.allowed is 
set? Why not just continue after having updated the target value?

Otherwise I think these patches look good,

Steve.

> -retry:
> +		}
> +	retry:
>   		gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
>   
>   		ap.target = data_blocks + ind_blocks;
>   		error = gfs2_inplace_reserve(ip, &ap);
>   		if (error) {
> -			if (error == -ENOSPC && bytes > sdp->sd_sb.sb_bsize) {
> -				bytes >>= 1;
> -				bytes &= bsize_mask;
> -				if (bytes == 0)
> -					bytes = sdp->sd_sb.sb_bsize;
> +			if (error == -ENOSPC && ap.allowed) {
> +				bytes = ap.allowed << sdp->sd_sb.sb_bsize_shift;
>   				goto retry;
>   			}
>   			goto out_qunlock;