Re: [PATCH 02/14] repair: reduce byte swap operations in scanfunc_allocbt

Eric Sandeen
2009-10-12T17:16:49Z

Christoph Hellwig wrote:

> Store native endian version of the extent startblock and length in
> local variables instead of converting them over and over again.
>
>
> Signed-off-by: Barry Naujok <bnaujok@sgi.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

I bet there's a lot more places where this could be done too :)

Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
> Index: xfsprogs-dev/repair/scan.c
> ===================================================================
> --- xfsprogs-dev.orig/repair/scan.c 2009-08-21 18:48:01.000000000 +0000
> +++ xfsprogs-dev/repair/scan.c 2009-08-21 18:54:29.000000000 +0000
> @@ -449,7 +449,6 @@ scanfunc_allocbt(
> __uint32_t magic)
> {
> const char *name;
> - xfs_agblock_t b, e;
> int i;
> xfs_alloc_ptr_t *pp;
> xfs_alloc_rec_t *rp;
> @@ -509,20 +508,21 @@ _("%s freespace btree block claimed (sta
>
> rp = XFS_ALLOC_REC_ADDR(mp, block, 1);
> for (i = 0; i < numrecs; i++) {
> - if (be32_to_cpu(rp[i].ar_blockcount) == 0 ||
> - be32_to_cpu(rp[i].ar_startblock) == 0 ||
> - !verify_agbno(mp, agno,
> - be32_to_cpu(rp[i].ar_startblock)) ||
> - be32_to_cpu(rp[i].ar_blockcount) >
> - MAXEXTLEN)
> - continue;
> + xfs_agblock_t b, end;
> + xfs_extlen_t len;
> +
> + b = be32_to_cpu(rp[i].ar_startblock);
> + len = be32_to_cpu(rp[i].ar_blockcount);
> + end = b + len;
>
> - e = be32_to_cpu(rp[i].ar_startblock) +
> - be32_to_cpu(rp[i].ar_blockcount);
> - if (!verify_agbno(mp, agno, e - 1))
> + if (b == 0 || !verify_agbno(mp, agno, b))
> + continue;
> + if (len == 0 || len > MAXEXTLEN)
> continue;
> - for (b = be32_to_cpu(rp[i].ar_startblock);
> - b < e; b++) {
> + if (!verify_agbno(mp, agno, end - 1))
> + continue;
> +
> + for ( ; b < end; b++) {
> state = get_agbno_state(mp, agno, b);
> switch (state) {
> case XR_E_UNKNOWN:
> @@ -579,6 +579,8 @@ _("%s freespace btree block claimed (sta
> }
>
> for (i = 0; i < numrecs; i++) {
> + xfs_agblock_t bno = be32_to_cpu(pp[i]);
> +
> /*
> * XXX - put sibling detection right here.
> * we know our sibling chain is good. So as we go,
> @@ -588,11 +590,11 @@ _("%s freespace btree block claimed (sta
> * pointer mismatch, try and extract as much data
> * as possible.
> */
> - if (be32_to_cpu(pp[i]) != 0 && verify_agbno(mp, agno,
> - be32_to_cpu(pp[i])))
> - scan_sbtree(be32_to_cpu(pp[i]), level, agno, suspect,
> + if (bno != 0 && verify_agbno(mp, agno, bno)) {
> + scan_sbtree(bno, level, agno, suspect,
> (magic == XFS_ABTB_MAGIC) ?
> scanfunc_bno : scanfunc_cnt, 0);
> + }
> }
> }
>
>
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