[Cluster-devel] [GFS2 Patch] GFS2: speed up delete/unlink performance for large files

[Steven Whitehouse]

Hi,

Now in the -nmw git tree. Many thanks for this - it looks really good
and will make a big difference to deallocation performance,

Steve.

On Thu, 2011-09-15 at 09:59 -0400, Bob Peterson wrote:
> Hi,
> 
> This patch improves the performance of delete/unlink
> operations in a GFS2 file system where the files are large
> by adding a layer of metadata read-ahead for indirect blocks.
> Mileage will vary, but on my system, deleting an 8.6G file
> dropped from 22 seconds to about 4.5 seconds.
> 
> Regards,
> 
> Bob Peterson
> Red Hat File Systems
> 
> Signed-off-by: Bob Peterson <rpeterso at redhat.com> 
> --
>  fs/gfs2/bmap.c |   26 +++++++++++++++++++++++---
>  1 files changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
> index 7878c47..7efa38c 100644
> --- a/fs/gfs2/bmap.c
> +++ b/fs/gfs2/bmap.c
> @@ -691,7 +691,7 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
>  {
>  	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
>  	struct buffer_head *bh = NULL;
> -	__be64 *top, *bottom;
> +	__be64 *top, *bottom, *t2;
>  	u64 bn;
>  	int error;
>  	int mh_size = sizeof(struct gfs2_meta_header);
> @@ -719,7 +719,27 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
>  	if (error)
>  		goto out;
>  
> -	if (height < ip->i_height - 1)
> +	if (height < ip->i_height - 1) {
> +		struct buffer_head *rabh;
> +
> +		for (t2 = top; t2 < bottom; t2++, first = 0) {
> +			if (!*t2)
> +				continue;
> +
> +			bn = be64_to_cpu(*t2);
> +			rabh = gfs2_getbuf(ip->i_gl, bn, CREATE);
> +			if (trylock_buffer(rabh)) {
> +				if (buffer_uptodate(rabh)) {
> +					unlock_buffer(rabh);
> +					brelse(rabh);
> +					continue;
> +				}
> +				rabh->b_end_io = end_buffer_read_sync;
> +				submit_bh(READA | REQ_META, rabh);
> +				continue;
> +			}
> +			brelse(rabh);
> +		}
>  		for (; top < bottom; top++, first = 0) {
>  			if (!*top)
>  				continue;
> @@ -731,7 +751,7 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
>  			if (error)
>  				break;
>  		}
> -
> +	}
>  out:
>  	brelse(bh);
>  	return error;
>