Re: [PATCH 1/9] metadump: clean up btree block region zeroing

Brian Foster
2016-01-04T19:11:55Z

On Tue, Dec 22, 2015 at 08:37:01AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Abstract out all the common operations in the btree block zeroing
> so that we only have one copy of offset/len calculations and don't
> require lots of casts for the pointer arithmetic.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

> db/metadump.c | 61 +++++++++++++++++++++++------------------------------------
> 1 file changed, 24 insertions(+), 37 deletions(-)
>
> diff --git a/db/metadump.c b/db/metadump.c
> index 8455fdd..a185da5 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -258,8 +258,8 @@ zero_btree_node(
> xfs_inobt_key_t *ikp;
> xfs_alloc_ptr_t *app;
> xfs_alloc_key_t *akp;
> - void *zp1, *zp2;
> - int zlen1, zlen2;
> + char *zp1, *zp2;
> + char *key_end;
>
> nrecs = be16_to_cpu(block->bb_numrecs);
>
> @@ -268,43 +268,36 @@ zero_btree_node(
> case TYP_BMAPBTD:
> bkp = XFS_BMBT_KEY_ADDR(mp, block, 1);
> bpp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
> - zp1 = &bkp[nrecs];
> - zlen1 = (char *)&bpp[0] - (char *)&bkp[nrecs];
> - zp2 = &bpp[nrecs];
> - zlen2 = (char *)block + mp->m_sb.sb_blocksize -
> - (char *)&bpp[nrecs];
> + zp1 = (char *)&bkp[nrecs];
> + zp2 = (char *)&bpp[nrecs];
> + key_end = (char *)bpp;
> break;
> case TYP_INOBT:
> case TYP_FINOBT:
> ikp = XFS_INOBT_KEY_ADDR(mp, block, 1);
> ipp = XFS_INOBT_PTR_ADDR(mp, block, 1, mp->m_inobt_mxr[1]);
> - zp1 = &ikp[nrecs];
> - zlen1 = (char *)&ipp[0] - (char *)&ikp[nrecs];
> - zp2 = &ipp[nrecs];
> - zlen2 = (char *)block + mp->m_sb.sb_blocksize -
> - (char *)&ipp[nrecs];
> + zp1 = (char *)&ikp[nrecs];
> + zp2 = (char *)&ipp[nrecs];
> + key_end = (char *)ipp;
> break;
> case TYP_BNOBT:
> case TYP_CNTBT:
> akp = XFS_ALLOC_KEY_ADDR(mp, block, 1);
> app = XFS_ALLOC_PTR_ADDR(mp, block, 1, mp->m_alloc_mxr[1]);
> - zp1 = &akp[nrecs];
> - zlen1 = (char *)&app[0] - (char *)&akp[nrecs];
> - zp2 = &app[nrecs];
> - zlen2 = (char *)block + mp->m_sb.sb_blocksize -
> - (char *)&app[nrecs];
> + zp1 = (char *)&akp[nrecs];
> + zp2 = (char *)&app[nrecs];
> + key_end = (char *)app;
> break;
> default:
> - zp1 = NULL;
> - break;
> + return;
> }
>
> - if (zp1 && zp2) {
> - /* Zero from end of keys to beginning of pointers */
> - memset(zp1, 0, zlen1);
> - /* Zero from end of pointers to end of block */
> - memset(zp2, 0, zlen2);
> - }
> +
> + /* Zero from end of keys to beginning of pointers */
> + memset(zp1, 0, key_end - zp1);
> +
> + /* Zero from end of pointers to end of block */
> + memset(zp2, 0, (char *)block + mp->m_sb.sb_blocksize - zp2);
> }
>
> static void
> @@ -316,8 +309,7 @@ zero_btree_leaf(
> struct xfs_bmbt_rec *brp;
> struct xfs_inobt_rec *irp;
> struct xfs_alloc_rec *arp;
> - void *zp;
> - int zlen;
> + char *zp;
>
> nrecs = be16_to_cpu(block->bb_numrecs);
>
> @@ -325,29 +317,24 @@ zero_btree_leaf(
> case TYP_BMAPBTA:
> case TYP_BMAPBTD:
> brp = XFS_BMBT_REC_ADDR(mp, block, 1);
> - zp = &brp[nrecs];
> - zlen = (char *)block + mp->m_sb.sb_blocksize - (char *)&brp[nrecs];
> + zp = (char *)&brp[nrecs];
> break;
> case TYP_INOBT:
> case TYP_FINOBT:
> irp = XFS_INOBT_REC_ADDR(mp, block, 1);
> - zp = &irp[nrecs];
> - zlen = (char *)block + mp->m_sb.sb_blocksize - (char *)&irp[nrecs];
> + zp = (char *)&irp[nrecs];
> break;
> case TYP_BNOBT:
> case TYP_CNTBT:
> arp = XFS_ALLOC_REC_ADDR(mp, block, 1);
> - zp = &arp[nrecs];
> - zlen = (char *)block + mp->m_sb.sb_blocksize - (char *)&arp[nrecs];
> + zp = (char *)&arp[nrecs];
> break;
> default:
> - zp = NULL;
> - break;
> + return;
> }
>
> /* Zero from end of records to end of block */
> - if (zp && zlen < mp->m_sb.sb_blocksize)
> - memset(zp, 0, zlen);
> + memset(zp, 0, (char *)block + mp->m_sb.sb_blocksize - zp);
> }
>
> static void
> --
> 2.5.0
>
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