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From: jim owens <jowens@hp.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: Chris Mason <chris.mason@oracle.com>, linux-fsdevel@vger.kernel.org
Subject: Re: btrfs O_DIRECT was [rfc] fsync_range?
Date: Wed, 21 Jan 2009 18:08:42 -0500	[thread overview]
Message-ID: <4977AAFA.7050503@hp.com> (raw)
In-Reply-To: <20090121215921.GG16133@shareable.org>

Jamie Lokier wrote:
> 
> Writing in place or new-place on a *non-shared* (i.e. non-snapshotted)
> file is the choice which is useful.  It's a filesystem implementation
> detail, not a semantic difference.  I'm suggesting writing in place
> may do no harm and be more like the expected behaviour with programs
> that use O_DIRECT, which are usually databases.
> 
> How about a btrfs mount option?
> in_place_write=never/always/direct_only.  (Default direct_only).

The harm is creating a special guarantee for just one case
of "don't move my data" based on a transient file open mode.

What about defragmenting or moving the extent to another
device for performance or for (failing) device removal?

We are on a slippery slope for presumed expectations.

jim

  reply	other threads:[~2009-01-21 23:08 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-20 16:47 [rfc] fsync_range? Nick Piggin
2009-01-20 18:31 ` Jamie Lokier
2009-01-20 21:25   ` Bryan Henderson
2009-01-20 22:42     ` Jamie Lokier
2009-01-21 19:43       ` Bryan Henderson
2009-01-21 21:08         ` Jamie Lokier
2009-01-21 22:44           ` Bryan Henderson
2009-01-21 23:31             ` Jamie Lokier
2009-01-21  1:36     ` Nick Piggin
2009-01-21 19:58       ` Bryan Henderson
2009-01-21 20:53         ` Jamie Lokier
2009-01-21 22:14           ` Bryan Henderson
2009-01-21 22:30             ` Jamie Lokier
2009-01-22  1:52               ` Bryan Henderson
2009-01-22  3:41                 ` Jamie Lokier
2009-01-21  1:29   ` Nick Piggin
2009-01-21  3:15     ` Jamie Lokier
2009-01-21  3:48       ` Nick Piggin
2009-01-21  5:24         ` Jamie Lokier
2009-01-21  6:16           ` Nick Piggin
2009-01-21 11:18             ` Jamie Lokier
2009-01-21 11:41               ` Nick Piggin
2009-01-21 12:09                 ` Jamie Lokier
2009-01-21  4:16       ` Nick Piggin
2009-01-21  4:59         ` Jamie Lokier
2009-01-21  6:23           ` Nick Piggin
2009-01-21 12:02             ` Jamie Lokier
2009-01-21 12:13             ` Theodore Tso
2009-01-21 12:37               ` Jamie Lokier
2009-01-21 14:12                 ` Theodore Tso
2009-01-21 14:35                   ` Chris Mason
2009-01-21 15:58                     ` Eric Sandeen
2009-01-21 20:41                     ` Jamie Lokier
2009-01-21 21:23                       ` jim owens
2009-01-21 21:59                         ` Jamie Lokier
2009-01-21 23:08                           ` jim owens [this message]
2009-01-22  0:06                             ` btrfs O_DIRECT was " Jamie Lokier
2009-01-22 13:50                               ` jim owens
2009-01-22 21:18                   ` Florian Weimer
2009-01-22 21:23                     ` Florian Weimer
2009-01-21  3:25     ` Jamie Lokier
2009-01-21  3:52       ` Nick Piggin

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