From: Daniel Phillips <phillips@phunq.net>
To: Christoph Hellwig <hch@lst.de>
Cc: McPacino <mcpacino@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
dm-devel@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Nick Piggin <npiggin@kernel.dk>
Subject: Re: introduce dm-snap-mv
Date: Fri, 8 Oct 2010 06:22:57 -0700 [thread overview]
Message-ID: <201010080622.58095.phillips@phunq.net> (raw)
In-Reply-To: <20101008092427.GA5426@lst.de>
On Friday 08 October 2010, Christoph Hellwig wrote:
> On Fri, Oct 08, 2010 at 05:14:27PM +0800, McPacino wrote:
> > Hi Christoph,
> >
> > I have to take care the cache problem If using the bio directly.
> > BHs can be released by kernel when necessary.
> >
> > Is there any existing code using bio to read/write metadata
> > blocks? How do they handle the timing freeing bios? I really
> > wish to learn something form it.
>
> If you actually need caching just use the pagecache, e.g.
> read_mapping_page to read in your data. That completely abstracts
> away the underlying block size.
And that will automatically give him the PAGE_CACHE_SIZE objects he
wants. I still don't understand why his model cannot be generalized
to arbitrary block size specifiable at create time.
Regards,
Daniel
next prev parent reply other threads:[~2010-10-08 13:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-06 8:31 introduce dm-snap-mv Cong Meng
2010-10-07 21:31 ` Daniel Phillips
2010-10-08 8:22 ` Christoph Hellwig
2010-10-08 9:14 ` McPacino
2010-10-08 9:24 ` Christoph Hellwig
2010-10-08 9:28 ` McPacino
2010-10-08 13:22 ` Daniel Phillips [this message]
2010-10-13 16:45 ` McPacino
2010-10-08 9:01 ` McPacino
2010-10-19 19:58 ` [dm-devel] " Mikulas Patocka
2010-11-06 3:24 ` Daniel Phillips
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