From: "Pádraig Brady" <P@draigBrady.com>
To: Andreas Dilger <adilger@dilger.ca>
Cc: "Pavel Machek" <pavel@ucw.cz>, "Jörn Engel" <joern@logfs.org>,
"Andy Lutomirski" <luto@amacapital.net>,
"Zach Brown" <zab@redhat.com>,
"Myklebust, Trond" <Trond.Myklebust@netapp.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Ric Wheeler" <rwheeler@redhat.com>,
"Linux FS Devel" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Chris L. Mason" <clmason@fusionio.com>,
"Christoph Hellwig" <hch@infradead.org>,
"Alexander Viro" <aviro@redhat.com>,
"Martin K. Petersen" <mkp@mkp.net>,
"Hannes Reinecke" <hare@suse.de>,
"Joel Becker" <jlbec@evilplan.org>
Subject: Re: New copyfile system call - discuss before LSF?
Date: Sun, 31 Mar 2013 12:48:36 +0100 [thread overview]
Message-ID: <51582294.1000806@draigBrady.com> (raw)
In-Reply-To: <08D26E22-3856-43A4-8835-48C86CC5F71C@dilger.ca>
On 03/30/2013 08:08 PM, Andreas Dilger wrote:
> On 2013-03-30, at 12:49 PM, Pavel Machek wrote:
>> Hmm, really? AFAICT it would be simple to provide an
>> open_deleted_file("directory") syscall. You'd open_deleted_file(),
>> copy source file into it, then fsync(), then link it into filesystem.
>>
>> That should have atomicity properties reflected.
>
> Actually, the open_deleted_file() syscall is quite useful for many
> different things all by itself. Lots of applications need to create
> temporary files that are unlinked at application failure (without a
> race if app crashes after creating the file, but before unlinking).
> It also avoids exposing temporary files into the namespace if other
> applications are accessing the directory.
>
> We've added a library routine that does this for Lustre in a hackish
> way (magical filename created in target directory) for being able to
> migrate files between data servers, HSM, defragmentation, rsync, etc.
>
> Cheers, Andreas
This reminds me of the flink() discussion:
http://marc.info/?l=linux-kernel&m=104965452917349
Also kinda related is the exchangedata() OSX system call to
"atomically exchange data between two files"
thanks,
Pádraig.
next prev parent reply other threads:[~2013-03-31 11:48 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-21 11:37 New copyfile system call - discuss before LSF? Ric Wheeler
2013-02-21 13:37 ` Hannes Reinecke
2013-02-21 13:51 ` Myklebust, Trond
2013-02-21 14:57 ` Ric Wheeler
2013-02-21 16:36 ` Andreas Dilger
2013-02-21 20:00 ` Paolo Bonzini
2013-02-21 20:50 ` Myklebust, Trond
2013-02-21 22:24 ` Zach Brown
2013-02-22 1:29 ` Myklebust, Trond
2013-02-23 0:32 ` Eric Wong
2013-03-30 19:45 ` Pavel Machek
2013-03-31 21:23 ` Eric Wong
2013-02-22 9:47 ` Paolo Bonzini
2013-02-22 9:52 ` Ric Wheeler
2013-02-22 18:22 ` Zach Brown
2013-02-22 22:48 ` Myklebust, Trond
2013-02-25 21:14 ` Andy Lutomirski
2013-02-25 21:49 ` Ric Wheeler
2013-02-25 21:59 ` Myklebust, Trond
2013-02-25 22:16 ` Andy Lutomirski
2013-02-25 23:28 ` Myklebust, Trond
2013-02-25 23:35 ` Andy Lutomirski
2013-02-25 23:45 ` Myklebust, Trond
2013-02-26 0:03 ` Zach Brown
2013-03-11 9:31 ` Joel Becker
2013-02-26 21:02 ` Jörn Engel
2013-02-26 22:35 ` Andy Lutomirski
2013-03-30 19:49 ` Pavel Machek
2013-03-30 20:08 ` Andreas Dilger
2013-03-30 21:45 ` Pavel Machek
2013-03-30 21:57 ` Myklebust, Trond
2013-03-30 23:21 ` Ric Wheeler
2013-03-31 2:53 ` Andreas Dilger
2013-03-31 3:52 ` Myklebust, Trond
2013-03-31 4:18 ` Andy Lutomirski
2013-03-31 4:36 ` Myklebust, Trond
2013-03-31 4:45 ` Myklebust, Trond
2013-04-01 15:49 ` J. Bruce Fields
2013-03-31 7:36 ` Pavel Machek
2013-03-31 18:27 ` Myklebust, Trond
2013-03-31 18:32 ` openat(..., AT_UNLINKED) was " Pavel Machek
2013-03-31 18:44 ` Myklebust, Trond
2013-03-31 22:50 ` Pavel Machek
2013-03-31 23:14 ` Ric Wheeler
2013-03-31 23:18 ` Pavel Machek
2013-03-31 23:28 ` Ric Wheeler
2013-03-31 23:41 ` Pavel Machek
2013-03-31 5:38 ` AEDilger Gmail
2013-03-31 8:25 ` Pavel Machek
2013-03-31 11:48 ` Pádraig Brady [this message]
2013-03-30 22:40 ` Andy Lutomirski
2013-02-21 22:05 ` Ric Wheeler
2013-02-21 22:13 ` Myklebust, Trond
2013-02-22 8:47 ` Ric Wheeler
2013-02-21 18:29 ` Jeremy Allison
2013-02-22 0:29 ` Eric Wong
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