From: Phillip Susi <psusi@cfl.rr.com>
To: Chris Mason <chris.mason@oracle.com>
Cc: Olaf van der Spek <olafvdspek@gmail.com>,
linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Atomic file data replace API
Date: Fri, 07 Jan 2011 20:11:04 -0500 [thread overview]
Message-ID: <4D27B9A8.3020804@cfl.rr.com> (raw)
In-Reply-To: <1294412141-sup-1734@think>
On 01/07/2011 09:58 AM, Chris Mason wrote:
> Yes and no. We have a best effort mechanism where we try to guess that
> since you've done this truncate and the write that you want the writes
> to show up quickly. But its a guess.
It is a pretty good guess, and one that the NT kernel has been making
for 15 years or so. I've been following this issue for some time and I
still don't understand why Ted is so hostile to this and can't make it
work right on ext4. When you get a rename() you just need to check if
there are outstanding journal transactions and/or dirty cache pages, and
hang the rename() transaction on the end of those. That way if the
system crashes after the new file has fully hit the disk, the old file
is gone and you only have the new one, but if it crashes before, you
still have the old one in place.
Both the writes and the rename can be delayed in the cache to an
arbitrary point in the future; what matters is that their order is
preserved.
prev parent reply other threads:[~2011-01-08 1:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-06 20:01 Atomic file data replace API Olaf van der Spek
2011-01-07 13:55 ` Mike Fleetwood
2011-01-07 14:01 ` Olaf van der Spek
2011-01-07 14:10 ` Olaf van der Spek
2011-01-07 14:58 ` Chris Mason
2011-01-07 15:01 ` Olaf van der Spek
2011-01-07 15:05 ` Chris Mason
2011-01-07 15:08 ` Olaf van der Spek
2011-01-07 15:13 ` Chris Mason
2011-01-07 15:17 ` Olaf van der Spek
2011-01-07 16:12 ` Chris Mason
2011-01-07 16:19 ` Olaf van der Spek
2011-01-07 16:26 ` Hubert Kario
2011-01-07 19:29 ` Chris Mason
2011-01-08 14:40 ` Olaf van der Spek
2011-01-26 18:30 ` Olaf van der Spek
2011-01-26 19:30 ` Chris Mason
2011-01-26 21:56 ` Olaf van der Spek
2011-01-07 16:32 ` Massimo Maggi
2011-01-07 16:34 ` Olaf van der Spek
2011-01-07 19:29 ` Thomas Bellman
2011-01-08 14:36 ` Olaf van der Spek
2011-01-08 21:43 ` Thomas Bellman
2011-01-09 15:16 ` Olaf van der Spek
2011-01-09 18:56 ` Thomas Bellman
2011-01-09 19:06 ` Olaf van der Spek
2011-01-09 20:13 ` Phillip Susi
2011-01-08 1:11 ` Phillip Susi [this message]
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