Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756438Ab3CaIZx (ORCPT ); Sun, 31 Mar 2013 04:25:53 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:37102 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755309Ab3CaIZu (ORCPT ); Sun, 31 Mar 2013 04:25:50 -0400 Date: Sun, 31 Mar 2013 10:25:48 +0200 From: Pavel Machek To: AEDilger Gmail Cc: Andreas Dilger , =?iso-8859-1?Q?J=F6rn?= Engel , Andy Lutomirski , Zach Brown , "Myklebust, Trond" , Paolo Bonzini , Ric Wheeler , Linux FS Devel , "linux-kernel@vger.kernel.org" , "Chris L. Mason" , Christoph Hellwig , Alexander Viro , "Martin K. Petersen" , Hannes Reinecke , Joel Becker Subject: Re: New copyfile system call - discuss before LSF? Message-ID: <20130331082548.GA15385@amd.pavel.ucw.cz> References: <512635D2.4090207@redhat.com> <51267CEB.8070805@redhat.com> <4FA345DA4F4AE44899BD2B03EEEC2FA9235DAA99@SACEXCMBX04-PRD.hq.netapp.com> <20130221222449.GY22221@lenny.home.zabbo.net> <512BD44C.40907@amacapital.net> <20130226210232.GA19510@logfs.org> <20130330194933.GB1005@amd.pavel.ucw.cz> <08D26E22-3856-43A4-8835-48C86CC5F71C@dilger.ca> <20130330214509.GB4322@amd.pavel.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1745 Lines: 38 Hi! On Sat 2013-03-30 22:38:35, AEDilger Gmail wrote: > On 2013-03-30, at 14:45, Pavel Machek wrote: > > On Sat 2013-03-30 13:08:39, 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. > > > > Hmm. open_deleted_file() will still need to get a directory... so it > > will still need a path. Perhaps open("/foo/bar/mnt", O_DELETED) would > > be acceptable interface? > > Yes, that would be reasonable, and/or possibly openat(fd, NULL, AT_FDCWD|AT_UNLINKED)? openat() is better interface for this, I'd say. BTW... I don't think this has to be done at the same time as splice() [or how it ends up being called] changes... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/