Date: Mon, 13 Aug 2012 14:46:54 -0700
From: Kent Overstreet <koverstreet@google.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
        dm-devel@redhat.com, axboe@kernel.dk, agk@redhat.com, neilb@suse.de,
        drbd-dev@lists.linbit.com, vgoyal@redhat.com, mpatocka@redhat.com,
        sage@newdream.net, yehuda@hq.newdream.net
Subject: Re: [PATCH v5 12/12] block: Only clone bio vecs that are in use
Message-ID: <20120813214654.GD9541@google.com>
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On Thu, Aug 09, 2012 at 10:37:00AM -0700, Tejun Heo wrote:
> Hello,
> 
> On Mon, Aug 06, 2012 at 03:08:41PM -0700, Kent Overstreet wrote:
> > bcache creates large bios internally, and then splits them according to
> > the device requirements before it sends them down. If a lower level
> > device tries to clone the bio, and the original bio had more than
> > BIO_MAX_PAGES, the clone will fail unecessarily.
> > 
> > We can fix this by only cloning the bio vecs that are actually in use.
> 
> How was this tested?

This code has been in the bcache tree for months, and I added it to fix
a real bug (think I saw it with bcache on top of dm) - and since then
it's been tested in probably just about all the relevant configurations,
certainly both dm and md.
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