From: Mingming <cmm@us.ibm.com>
To: Eric Sandeen <sandeen@redhat.com>
Cc: Curt Wohlgemuth <curtw@google.com>,
ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH RFC] Insure direct IO writes do not use the page cache
Date: Wed, 29 Jul 2009 15:17:05 -0700 [thread overview]
Message-ID: <1248905825.4035.142.camel@mingming-laptop> (raw)
In-Reply-To: <4A70A77B.6080006@redhat.com>
On Wed, 2009-07-29 at 14:48 -0500, Eric Sandeen wrote:
> Eric Sandeen wrote:
> ...
>
> > Also, IIRC xfs does the conversion to written (vs. unwritten) extents in
> > an IO completion handler, just FWIW.
>
> After talking w/ Jeff Moyer, realized that w/o using the io completion,
> there's a race with AIO.
>
> Userspace will get notified that the write is done before the extents
> get flipped to initialized ....
Yes, for the AIO case, the DIO submit the IO and returns without waiting
for IO to complete. If we do conversion in ext4_direct_IO, then we could
convert the extents before the real IO hit to disk. Could cause stale
data exposed if crash before the data written to disk.
>
> -Eric
> --
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next prev parent reply other threads:[~2009-07-29 22:17 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-29 0:28 [PATCH RFC] Insure direct IO writes do not use the page cache Curt Wohlgemuth
2009-07-29 16:10 ` Curt Wohlgemuth
2009-07-29 17:18 ` Eric Sandeen
2009-07-29 17:41 ` Eric Sandeen
2009-07-29 19:48 ` Eric Sandeen
2009-07-29 22:17 ` Mingming [this message]
2009-07-29 17:47 ` Mingming
2009-07-29 18:10 ` Theodore Tso
2009-07-30 18:30 ` Jan Kara
2009-07-30 18:39 ` Eric Sandeen
2009-07-30 18:44 ` Jan Kara
2009-07-30 19:16 ` Eric Sandeen
2009-07-30 20:33 ` Theodore Tso
2009-07-31 16:10 ` Curt Wohlgemuth
2009-08-01 6:56 ` [PATCH RFC] ext4 direct IO for holes, fallocate Mingming
2009-08-03 16:47 ` Aneesh Kumar K.V
2009-08-03 23:40 ` Mingming
2009-07-31 17:58 ` [PATCH RFC] Insure direct IO writes do not use the page cache Mingming
2009-07-31 18:03 ` Michael Rubin
2009-07-31 18:03 ` Michael Rubin
2009-08-03 9:36 ` Jan Kara
2009-07-30 11:06 ` Aneesh Kumar K.V
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