From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org,
Liu Yiding <liuyd.fnst@cn.fujitsu.com>,
kernel test robot <rong.a.chen@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] block: fix .bi_size overflow
Date: Mon, 1 Jul 2019 14:46:30 +0800 [thread overview]
Message-ID: <20190701064628.GC16809@ming.t460p> (raw)
In-Reply-To: <20190701063613.GA20733@lst.de>
On Mon, Jul 01, 2019 at 08:36:13AM +0200, Christoph Hellwig wrote:
> On Mon, Jul 01, 2019 at 12:16:44PM +0800, Ming Lei wrote:
> > 'bio->bi_iter.bi_size' is 'unsigned int', which at most hold 4G - 1
> > bytes.
> >
> > Before 07173c3ec276 ("block: enable multipage bvecs"), one bio can
> > include very limited pages, and usually at most 256, so the fs bio
> > size won't be bigger than 1M bytes most of times.
> >
> > Since we support multi-page bvec, in theory one fs bio really can
> > be added > 1M pages, especially in case of hugepage, or big writeback
> > in case of huge dirty pages. Then there is chance in which .bi_size
> > is overflowed.
> >
> > Fixes this issue by adding bio_will_full() which checks if the added
> > segment may overflow .bi_size.
>
> Can you please just add the argument to bio_full? bio_will_full sounds
> rather odd.
OK.
>
> Maybe also add a kerneldoc comment to the new bio_full to explain
> it. Otherwise this looks fine to me.
Fine.
Thanks,
Ming
prev parent reply other threads:[~2019-07-01 6:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-01 4:16 [PATCH] block: fix .bi_size overflow Ming Lei
2019-07-01 6:36 ` Christoph Hellwig
2019-07-01 6:46 ` Ming Lei [this message]
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