From: "J. Bruce Fields" <bfields@fieldses.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Howells <dhowells@redhat.com>, Zach Brown <zab@redhat.com>,
Jan Kara <jack@suse.cz>, Andy Lutomirski <luto@amacapital.net>,
"mszeredi@suse.cz" <mszeredi@suse.cz>
Subject: Re: [PATCH 05/11] vfs: add RENAME_NOREPLACE flag
Date: Wed, 15 Jan 2014 18:31:50 -0500 [thread overview]
Message-ID: <20140115233149.GA9457@fieldses.org> (raw)
In-Reply-To: <CAJfpeguPj-P3tYx8w7-Sqma0K8SSbRxEQdGhTGMs=FtVRC8QSg@mail.gmail.com>
On Wed, Jan 15, 2014 at 07:35:04PM +0100, Miklos Szeredi wrote:
> On Wed, Jan 15, 2014 at 7:19 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> > On Wed, Jan 08, 2014 at 11:10:09PM +0100, Miklos Szeredi wrote:
> >> From: Miklos Szeredi <mszeredi@suse.cz>
> >>
> >> If this flag is specified and the target of the rename exists then the
> >> rename syscall fails with EEXIST.
> >
> > Why is this useful?
> >
> > (I'm sure it is, it'd just be useful to have the reasons recorded
> > someplace.)
> >
> >> The VFS does the existence checking, so it is trivial to enable for most
> >> local filesystems. This patch only enables it in ext4.
> >>
> >> For network filesystems the VFS check is not enough as there may be a race
> >> between a remote create and the rename, so these filesystems need to handle
> >> this flag in their ->rename() implementations to ensure atomicity.
> >
> > Till that's done this should probably result in -EOPNOTSUPP on those
> > filesystems?
> >
> > I think this would need new protocol in the NFS case.
>
> Yes, it needs to be enabled on a case-by-case basis.
Oh, right, I missed all those
if (flags)
return -EOPNOTSUPP;
added with "vfs: add renameat2 syscall". Apologies.
> Only enabled for
> ext4 now, but trivial to do for most fs.
Got it, thanks!
--b.
next prev parent reply other threads:[~2014-01-15 23:31 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 22:10 [PATCH 00/11] cross rename v3 Miklos Szeredi
2014-01-08 22:10 ` [PATCH 01/11] vfs: add d_is_dir() Miklos Szeredi
2014-01-08 22:10 ` [PATCH 02/11] vfs: rename: move d_move() up Miklos Szeredi
2014-01-08 22:10 ` [PATCH 03/11] vfs: rename: use common code for dir and non-dir Miklos Szeredi
2014-01-08 22:10 ` [PATCH 04/11] vfs: add renameat2 syscall Miklos Szeredi
2014-01-14 22:11 ` Tetsuo Handa
2014-01-15 10:30 ` Miklos Szeredi
2014-01-15 13:50 ` Miklos Szeredi
2014-01-18 10:40 ` Tetsuo Handa
2014-01-08 22:10 ` [PATCH 05/11] vfs: add RENAME_NOREPLACE flag Miklos Szeredi
2014-01-15 18:19 ` J. Bruce Fields
2014-01-15 18:26 ` Andy Lutomirski
2014-01-15 23:33 ` J. Bruce Fields
2014-01-16 10:45 ` Miklos Szeredi
2014-01-15 18:35 ` Miklos Szeredi
2014-01-15 23:31 ` J. Bruce Fields [this message]
2014-01-08 22:10 ` [PATCH 06/11] security: add flags to rename hooks Miklos Szeredi
2014-01-08 22:10 ` [PATCH 07/11] vfs: add cross-rename Miklos Szeredi
2014-01-13 7:52 ` Jan Kara
2014-01-14 10:31 ` Miklos Szeredi
2014-01-14 12:47 ` Jan Kara
2014-01-08 22:10 ` [PATCH 08/11] ext4: rename: create ext4_renament structure for local vars Miklos Szeredi
2014-01-08 22:10 ` [PATCH 09/11] ext4: rename: move EMLINK check up Miklos Szeredi
2014-01-08 22:10 ` [PATCH 10/11] ext4: rename: split out helper functions Miklos Szeredi
2014-01-08 22:10 ` [PATCH 11/11] ext4: add cross rename support Miklos Szeredi
2014-01-13 12:25 ` Jan Kara
2014-01-14 10:35 ` Miklos Szeredi
2014-01-15 18:23 ` J. Bruce Fields
2014-01-15 18:31 ` Miklos Szeredi
2014-01-16 10:54 ` Miklos Szeredi
2014-01-16 14:48 ` J. Bruce Fields
2014-01-17 10:53 ` Michael Kerrisk (man-pages)
2014-01-17 14:41 ` Miklos Szeredi
2014-04-19 9:08 ` Michael Kerrisk (man-pages)
2014-04-19 12:08 ` Tetsuo Handa
2014-04-23 14:24 ` Miklos Szeredi
2014-04-24 11:20 ` [PATCH (for 3.15) 0/5] Fix cross rename race window for LSM Tetsuo Handa
2014-04-24 11:22 ` [PATCH (for 3.15) 1/5] LSM: Pass the rename flags to each LSM module Tetsuo Handa
2014-04-25 20:49 ` Casey Schaufler
2014-04-24 11:23 ` [PATCH (for 3.15) 2/5] SELinux: Handle the rename flags Tetsuo Handa
2014-04-24 11:24 ` [PATCH (for 3.15) 3/5] AppArmor: " Tetsuo Handa
2014-04-24 11:25 ` [PATCH (for 3.15) 4/5] TOMOYO: " Tetsuo Handa
2014-04-24 11:26 ` [PATCH (for 3.15) 5/5] LSM: Remove duplicated rename handling Tetsuo Handa
2014-05-01 11:58 ` [PATCH (for 3.15) 0/5] Fix cross rename race window for LSM Tetsuo Handa
2014-05-05 5:49 ` Tetsuo Handa
2014-05-11 15:53 ` Tetsuo Handa
2014-05-12 13:21 ` [PATCH (for 3.15) 0/5] Fix cross rename regressions " Tetsuo Handa
2014-05-12 13:22 ` [PATCH (for 3.15) 1/5] LSM: Pass the rename flags to each LSM module Tetsuo Handa
2014-05-19 12:19 ` John Johansen
2014-05-12 13:23 ` [PATCH (for 3.15) 2/5] SELinux: Handle the rename flags Tetsuo Handa
2014-05-12 13:24 ` [PATCH (for 3.15) 3/5] AppArmor: " Tetsuo Handa
2014-05-19 12:28 ` John Johansen
2014-05-12 13:25 ` [PATCH (for 3.15) 4/5] TOMOYO: " Tetsuo Handa
2014-05-12 13:25 ` [PATCH (for 3.15) 5/5] LSM: Remove duplicated rename handling Tetsuo Handa
2014-05-19 12:34 ` John Johansen
2014-04-23 14:21 ` [PATCH 11/11] ext4: add cross rename support Miklos Szeredi
2014-04-23 19:01 ` Michael Kerrisk (man-pages)
2014-01-17 22:08 ` J. Bruce Fields
2014-01-18 6:49 ` Miklos Szeredi
2014-01-18 16:27 ` J. Bruce Fields
2014-01-20 11:39 ` Miklos Szeredi
2014-01-20 11:50 ` Michael Kerrisk (man-pages)
2014-01-13 12:46 ` [PATCH 00/11] cross rename v3 Tetsuo Handa
2014-01-13 17:08 ` Miklos Szeredi
2014-01-13 22:03 ` Tetsuo Handa
2014-01-14 9:58 ` Miklos Szeredi
2014-01-14 13:03 ` Tetsuo Handa
2014-01-14 20:10 ` John Johansen
2014-01-14 20:53 ` Tetsuo Handa
2014-01-15 10:10 ` Miklos Szeredi
-- strict thread matches above, loose matches on Subject: below --
2013-11-20 13:01 [PATCH 00/11] cross rename v2 Miklos Szeredi
2013-11-20 13:01 ` [PATCH 05/11] vfs: add RENAME_NOREPLACE flag Miklos Szeredi
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