From: Les Mikesell <lesmikesell@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] fsync() and LVM
Date: Tue, 17 Mar 2009 13:17:02 -0500 [thread overview]
Message-ID: <49BFE91E.4030600@gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0903171243310.28733@bmsred.bmsi.com>
Stuart D. Gathman wrote:
> On Tue, 17 Mar 2009, Marco Colombo wrote:
>
>> It seems to me that in my setup, disabling the caches on the disks does
>> bring data to the platters, and that noone is "lying" about fsync.
>>
>> Now I'm _really_ confused.
>
> That's been my claim all along - that the broken fsync only affects
> on disk cache. LVM itself does not reorder writes in any way - it just
> fails to pass along the write barrier. fsync() does *start* writing
> the dirty buffers (implemented in the fs code). It just doesn't
> wait for the writes to finish getting to the platters. Apparently,
> it does wait for the write to get to the drive (but I'm not certain).
Given that fsync() is supposed to return the status of the completion of
the physical write, that sounds broken to me. Do the LVM's in question
here have more than one underlying device, and does it matter?
--
Les Mikesell
lesmikesell@gmail.com
next prev parent reply other threads:[~2009-03-17 18:17 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-13 17:46 [linux-lvm] fsync() and LVM Marco Colombo
2009-03-13 20:08 ` Stuart D. Gathman
2009-03-13 20:29 ` Ben Chobot
2009-03-13 20:38 ` Alasdair G Kergon
2009-03-14 3:16 ` Marco Colombo
2009-03-14 9:07 ` Dietmar Maurer
2009-03-14 14:31 ` Stuart D. Gathman
2009-03-15 0:51 ` Marco Colombo
2009-03-16 11:02 ` Charles Marcus
2009-03-16 11:05 ` Martin Schröder
2009-03-16 11:18 ` Charles Marcus
2009-03-16 11:25 ` Dietmar Maurer
2009-03-16 14:36 ` Marco Colombo
2009-03-16 17:13 ` Stuart D. Gathman
2009-03-16 17:17 ` Stuart D. Gathman
2009-03-16 18:50 ` Les Mikesell
2009-03-16 19:36 ` Greg Freemyer
2009-03-16 19:55 ` [linux-lvm] liblvm status question ben scott
2009-03-16 20:58 ` Greg Freemyer
2009-03-17 10:38 ` Bryn M. Reeves
2009-03-17 18:42 ` ben scott
2009-03-17 20:52 ` Greg Freemyer
2009-03-16 20:28 ` [linux-lvm] fsync() and LVM Les Mikesell
2009-03-16 20:54 ` Greg Freemyer
2009-03-16 21:17 ` Les Mikesell
2009-03-16 21:36 ` Greg Freemyer
2009-03-16 21:53 ` Les Mikesell
2009-03-16 22:51 ` Joshua D. Drake
2009-03-17 15:33 ` Joshua D. Drake
2009-03-19 9:20 ` Tim Post
2009-03-16 21:57 ` Allen, Jack
2009-03-17 16:00 ` Marco Colombo
2009-03-17 17:40 ` Stuart D. Gathman
2009-03-17 18:17 ` Les Mikesell [this message]
2009-03-18 0:37 ` Marco Colombo
2009-03-15 8:51 ` Dietmar Maurer
2009-03-15 23:31 ` Marco Colombo
2009-03-17 18:12 ` Les Mikesell
2009-03-17 18:19 ` Dietmar Maurer
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