[Cluster-devel] [GFS2 PATCH] GFS2: Issue discards in 512b sectors

[Steven Whitehouse]

Hi,

On Fri, 2013-03-22 at 10:07 -0400, Bob Peterson wrote:
> Hi,
> 
> This patch changes GFS2's discard issuing code so that it calls
> function sb_issue_discard rather than blkdev_issue_discard. The
> code was calling blkdev_issue_discard and specifying the correct
> sector offset and sector size, but blkdev_issue_discard expects
> these values to be in terms of 512 byte sectors, even if the native
> sector size for the device is different. Calling sb_issue_discard
> with the BLOCK size instead ensures the correct block-to-512b-sector
> translation. I verified that "minlen" is specified in blocks, so
> comparing it to a number of blocks is correct.
> 

Now in the -nmw git tree. Thanks,

Steve.


> Regards,
> 
> Bob Peterson
> Red Hat File Systems
> 
> Signed-off-by: Bob Peterson <rpeterso at redhat.com> 
> ---
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index dddeb0f..0c5a575 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -1181,12 +1181,9 @@ int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
>  			     const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed)
>  {
>  	struct super_block *sb = sdp->sd_vfs;
> -	struct block_device *bdev = sb->s_bdev;
> -	const unsigned int sects_per_blk = sdp->sd_sb.sb_bsize /
> -					   bdev_logical_block_size(sb->s_bdev);
>  	u64 blk;
>  	sector_t start = 0;
> -	sector_t nr_sects = 0;
> +	sector_t nr_blks = 0;
>  	int rv;
>  	unsigned int x;
>  	u32 trimmed = 0;
> @@ -1206,35 +1203,34 @@ int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
>  		if (diff == 0)
>  			continue;
>  		blk = offset + ((bi->bi_start + x) * GFS2_NBBY);
> -		blk *= sects_per_blk; /* convert to sectors */
>  		while(diff) {
>  			if (diff & 1) {
> -				if (nr_sects == 0)
> +				if (nr_blks == 0)
>  					goto start_new_extent;
> -				if ((start + nr_sects) != blk) {
> -					if (nr_sects >= minlen) {
> -						rv = blkdev_issue_discard(bdev,
> -							start, nr_sects,
> +				if ((start + nr_blks) != blk) {
> +					if (nr_blks >= minlen) {
> +						rv = sb_issue_discard(sb,
> +							start, nr_blks,
>  							GFP_NOFS, 0);
>  						if (rv)
>  							goto fail;
> -						trimmed += nr_sects;
> +						trimmed += nr_blks;
>  					}
> -					nr_sects = 0;
> +					nr_blks = 0;
>  start_new_extent:
>  					start = blk;
>  				}
> -				nr_sects += sects_per_blk;
> +				nr_blks++;
>  			}
>  			diff >>= 2;
> -			blk += sects_per_blk;
> +			blk++;
>  		}
>  	}
> -	if (nr_sects >= minlen) {
> -		rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS, 0);
> +	if (nr_blks >= minlen) {
> +		rv = sb_issue_discard(sb, start, nr_blks, GFP_NOFS, 0);
>  		if (rv)
>  			goto fail;
> -		trimmed += nr_sects;
> +		trimmed += nr_blks;
>  	}
>  	if (ptrimmed)
>  		*ptrimmed = trimmed;
>