From: Brian Foster <bfoster@redhat.com>
To: Jan Kara <jack@suse.cz>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH v2] xfs: Fix rounding in xfs_alloc_fix_len()
Date: Wed, 4 Jun 2014 14:44:40 -0400 [thread overview]
Message-ID: <20140604184440.GC55624@bfoster.bfoster> (raw)
In-Reply-To: <1401900833-25485-1-git-send-email-jack@suse.cz>
On Wed, Jun 04, 2014 at 06:53:53PM +0200, Jan Kara wrote:
> Rounding in xfs_alloc_fix_len() is wrong. As the comment states, the
> result should be a number of a form (k*prod+mod) however due to sign
> mistake the result is different. As a result allocations on raid arrays
> could be misaligned in some cases.
>
> This also seems to fix occasional assertion failure:
> XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0)
> in xfs_alloc_ag_vextent_size().
>
> Also add an assertion that the result of xfs_alloc_fix_len() is of
> expected form.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
Looks good to me. Thanks Jan.
Reviewed-by: Brian Foster <bfoster@redhat.com>
> fs/xfs/xfs_alloc.c | 18 ++++++++----------
> 1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
> index c1cf6a336a72..1351a24d3cdc 100644
> --- a/fs/xfs/xfs_alloc.c
> +++ b/fs/xfs/xfs_alloc.c
> @@ -257,16 +257,14 @@ xfs_alloc_fix_len(
> k = rlen % args->prod;
> if (k == args->mod)
> return;
> - if (k > args->mod) {
> - if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen)
> - return;
> - } else {
> - if ((int)(rlen = rlen - args->prod - (args->mod - k)) <
> - (int)args->minlen)
> - return;
> - }
> - ASSERT(rlen >= args->minlen);
> - ASSERT(rlen <= args->maxlen);
> + if (k > args->mod)
> + rlen = rlen - (k - args->mod);
> + else
> + rlen = rlen - args->prod + (args->mod - k);
> + if ((int)rlen < (int)args->minlen)
> + return;
> + ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
> + ASSERT(rlen % args->prod == args->mod);
> args->len = rlen;
> }
>
> --
> 1.8.1.4
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
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next prev parent reply other threads:[~2014-06-04 18:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-04 16:53 [PATCH v2] xfs: Fix rounding in xfs_alloc_fix_len() Jan Kara
2014-06-04 18:44 ` Brian Foster [this message]
2014-06-13 15:02 ` Jan Kara
2014-06-13 23:56 ` Dave Chinner
2014-06-16 9:00 ` Jan Kara
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