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Re: [PATCH 1/3] metadump: contiguous metadata object need to be split

To: Dave Chinner <david@xxxxxxxxxxxxx>, xfs@xxxxxxxxxxx
Subject: Re: [PATCH 1/3] metadump: contiguous metadata object need to be split
From: Eric Sandeen <sandeen@xxxxxxxxxxx>
Date: Fri, 28 Feb 2014 11:52:20 -0600
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1393568723-982-2-git-send-email-david@xxxxxxxxxxxxx>
References: <1393568723-982-1-git-send-email-david@xxxxxxxxxxxxx> <1393568723-982-2-git-send-email-david@xxxxxxxxxxxxx>
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.3.0
On 2/28/14, 12:25 AM, Dave Chinner wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
> 
> On crc enabled filesystems with obfuscation enabled we need to be
> able to recalculate the CRCs on individual buffers.
> process_single_fsb_objects() reads a contiguous range of single
> block objects as a singel buffer, and hence we cannot correctly
> recalculate the CRCs on them.
> 
> Split the loop up into individual buffer reads, processing and
> writes rather than a single read, multiple block processing and a
> single write.
> 
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>

Looks good to me.

Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>

> ---
>  db/metadump.c | 46 ++++++++++++++++++++++++----------------------
>  1 file changed, 24 insertions(+), 22 deletions(-)
> 
> diff --git a/db/metadump.c b/db/metadump.c
> index 5baf83d..14902a7 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -1331,29 +1331,27 @@ process_single_fsb_objects(
>       int             ret = 0;
>       int             i;
>  
> -     push_cur();
> -     set_cur(&typtab[btype], XFS_FSB_TO_DADDR(mp, s), c * blkbb,
> -                     DB_RING_IGN, NULL);
> +     for (i = 0; i < c; i++) {
> +             push_cur();
> +             set_cur(&typtab[btype], XFS_FSB_TO_DADDR(mp, s), blkbb,
> +                             DB_RING_IGN, NULL);
>  
> -     if (!iocur_top->data) {
> -             xfs_agnumber_t  agno = XFS_FSB_TO_AGNO(mp, s);
> -             xfs_agblock_t   agbno = XFS_FSB_TO_AGBNO(mp, s);
> +             if (!iocur_top->data) {
> +                     xfs_agnumber_t  agno = XFS_FSB_TO_AGNO(mp, s);
> +                     xfs_agblock_t   agbno = XFS_FSB_TO_AGBNO(mp, s);
>  
> -             print_warning("cannot read %s block %u/%u (%llu)",
> -                             typtab[btype].name, agno, agbno, s);
> -             if (stop_on_read_error)
> -                     ret = -EIO;
> -             goto out_pop;
> +                     print_warning("cannot read %s block %u/%u (%llu)",
> +                                     typtab[btype].name, agno, agbno, s);
> +                     if (stop_on_read_error)
> +                             ret = -EIO;
> +                     goto out_pop;
>  
> -     }
> +             }
>  
> -     if (dont_obfuscate) {
> -             ret = write_buf(iocur_top);
> -             goto out_pop;
> -     }
> +             if (dont_obfuscate)
> +                     goto write;
>  
> -     dp = iocur_top->data;
> -     for (i = 0; i < c; i++) {
> +             dp = iocur_top->data;
>               switch (btype) {
>               case TYP_DIR2:
>                       if (o >= mp->m_dirleafblk)
> @@ -1371,13 +1369,17 @@ process_single_fsb_objects(
>               default:
>                       break;
>               }
> +
> +write:
> +             ret = write_buf(iocur_top);
> +out_pop:
> +             pop_cur();
> +             if (ret)
> +                     break;
>               o++;
> -             dp += mp->m_sb.sb_blocksize;
> +             s++;
>       }
> -     ret = write_buf(iocur_top);
>  
> -out_pop:
> -     pop_cur();
>       return ret;
>  }
>  
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> 

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