From: Josef Bacik <josef@redhat.com>
To: Mike Fedyk <mfedyk@mikefedyk.com>
Cc: Josef Bacik <josef@redhat.com>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, hch@infradead.org,
akpm@linux-foundation.org
Subject: Re: [PATCH 3/6] direct-io: do not merge logically non-contiguous requests
Date: Sat, 22 May 2010 10:02:17 -0400 [thread overview]
Message-ID: <20100522140217.GS32248@dhcp231-156.rdu.redhat.com> (raw)
In-Reply-To: <AANLkTikwPL8-WefVIMF1ldTZpWVHvS1Lbh4YB8MZ4eu0@mail.gmail.com>
On Fri, May 21, 2010 at 06:47:36PM -0700, Mike Fedyk wrote:
> On Fri, May 21, 2010 at 10:03 AM, Josef Bacik <josef@redhat.com> wrot=
e:
> > Btrfs cannot handle having logically non-contiguous requests submit=
ted. =A0For
> > example if you have
> >
> > Logical: =A0[0-4095][HOLE][8192-12287]
> > Physical: [0-4095] =A0 =A0 =A0[4096-8191]
> >
> > Normally the DIO code would put these into the same BIO's. =A0The p=
roblem is we
> > need to know exactly what offset is associated with what BIO so we =
can do our
> > checksumming and unlocking properly, so putting them in the same BI=
O doesn't
> > work. =A0So add another check where we submit the current BIO if th=
e physical
> > blocks are not contigous OR the logical blocks are not contiguous.
> >
> > Signed-off-by: Josef Bacik <josef@redhat.com>
> > ---
> >
> > V1->V2
> > -Be more verbose in the in-code comment
> >
> > =A0fs/direct-io.c | =A0 20 ++++++++++++++++++--
> > =A01 files changed, 18 insertions(+), 2 deletions(-)
> >
>=20
> Btrfs has been pretty much self-contained (working well compiled
> against 2.6.32 for example). Is there a way that this wouldn't just
> start silently breaking for people compiling the latest btrfs with
> dkms against older kernels?
Nope, you have to have these generic patches for DIO to work, so buildi=
ng btrfs
like this will stop working with earlier kernels. Thanks,
Josef
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next prev parent reply other threads:[~2010-05-22 14:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-21 17:03 [PATCH 1/6] fs: allow short direct-io reads to be completed via buffered IO Josef Bacik
2010-05-21 17:03 ` [PATCH 2/6] direct-io: add a hook for the fs to provide its own submit_bio function Josef Bacik
2010-05-21 17:03 ` [PATCH 3/6] direct-io: do not merge logically non-contiguous requests Josef Bacik
2010-05-22 1:47 ` Mike Fedyk
2010-05-22 14:02 ` Josef Bacik [this message]
2010-05-21 17:03 ` [PATCH 4/6] fs: kill blockdev_direct_IO_no_locking Josef Bacik
2010-05-21 17:03 ` [PATCH 5/6] Btrfs: add basic DIO read/write support Josef Bacik
2010-05-21 17:03 ` [PATCH 6/6] Btrfs: do aio_write instead of write Josef Bacik
2010-05-23 8:31 ` Shi Weihua
2010-05-23 23:59 ` Josef Bacik
2010-05-27 3:06 ` liubo
2010-05-27 3:13 ` liubo
2010-05-27 12:59 ` Chris Mason
2010-05-28 1:42 ` liubo
2010-05-30 9:33 ` Dmitri Nikulin
2010-06-01 13:19 ` Chris Mason
2010-06-01 23:20 ` Dmitri Nikulin
-- strict thread matches above, loose matches on Subject: below --
2010-05-19 20:24 [PATCH 1/6] fs: allow short direct-io reads to be completed via buffered IO V2 Josef Bacik
2010-05-19 20:24 ` [PATCH 3/6] direct-io: do not merge logically non-contiguous requests Josef Bacik
2010-05-21 15:21 ` Christoph Hellwig
2010-05-21 15:37 ` Josef Bacik
2010-05-21 15:35 ` Christoph Hellwig
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