From: "J. Bruce Fields" <bfields@fieldses.org>
To: Guo Chao <yan@linux.vnet.ibm.com>
Cc: "J. Bruce Fields" <bfields@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH 05/13] vfs: take i_mutex on renamed file
Date: Mon, 10 Sep 2012 10:35:41 -0400 [thread overview]
Message-ID: <20120910143541.GC30136@fieldses.org> (raw)
In-Reply-To: <20120910024051.GA10405@yanx>
On Mon, Sep 10, 2012 at 10:40:51AM +0800, Guo Chao wrote:
> On Fri, Sep 07, 2012 at 05:39:01PM -0400, J. Bruce Fields wrote:
> > On Fri, Sep 07, 2012 at 10:27:05AM +0800, Guo Chao wrote:
> > > One script ...
> > >
> > > #!/bin/bash
> > > while true
> > > do
> > > mount -t sysfs nodev mnt && umount mnt
> > > done
> > >
> > >
> > >
> > > The other ...
> > >
> > > #!/bin/bash
> > > while true
> > > do
> > > mv mnt mnt2 && mv mnt2 mnt
> > > done
> > >
> > >
> > >
> > > Run them simultaneously in two consoles. When mount keeps reporting
> > > 'mount point mnt does not exist', stop them, then you will see the
> > > familiar sysfs under mnt2.
> >
> > Oh, thanks, for some reason I assumed it would be more difficult to
> > reproduce.
> >
> > I think we can do this--I don't think it even requires any care to the
> > locking order of the renamed vs the victim directory, though I can't
> > completely convince myself of that.
> >
> > Is it necessary to fix this, though? Does it cause any problems other
> > than unexpected behavior?
> >
> > --b.
> > --
>
> Hard to say whether it's a bug or what's problems of being able to rename
> mountpoint.
>
> Anyway, this patch closes this race when mountpoint is a file. Thus we get
> different behaviour when deal with files and directories. It's apparently
> not well-defined, but again, is it a problem? Not sure ... ...
OK. I'm not seeing a strong argument to change the current behavior, so
inclined to leave it alone for now.
--b.
next prev parent reply other threads:[~2012-09-10 14:35 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-05 20:55 [RFC PATCH 00/13] Implement NFSv4 delegations, take 4 J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 01/13] gfs2: Get rid of I_MUTEX_QUOTA usage J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-05 20:59 ` J. Bruce Fields
2012-09-05 20:59 ` J. Bruce Fields
2012-09-06 14:27 ` Steven Whitehouse
2012-09-06 14:27 ` Steven Whitehouse
2012-09-06 17:08 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 02/13] vfs: pull ext4's double-i_mutex-locking into common code J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-06 2:53 ` Guo Chao
2012-09-06 13:49 ` J. Bruce Fields
2012-09-06 13:49 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 03/13] vfs: don't use PARENT/CHILD lock classes for non-directories J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 04/13] vfs: rename I_MUTEX_QUOTA now that it's not used for quotas J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 05/13] vfs: take i_mutex on renamed file J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-06 3:05 ` Guo Chao
2012-09-06 3:05 ` Guo Chao
2012-09-06 17:51 ` J. Bruce Fields
2012-09-06 17:51 ` J. Bruce Fields
2012-09-07 2:27 ` Guo Chao
2012-09-07 2:27 ` Guo Chao
2012-09-07 21:39 ` J. Bruce Fields
2012-09-07 21:39 ` J. Bruce Fields
2012-09-10 2:40 ` Guo Chao
2012-09-10 2:40 ` Guo Chao
2012-09-10 5:10 ` Ram Pai
2012-09-10 5:10 ` Ram Pai
2012-09-10 6:37 ` Guo Chao
2012-09-10 6:37 ` Guo Chao
2012-09-10 7:27 ` Ram Pai
2013-02-14 2:01 ` Al Viro
2012-09-10 14:35 ` J. Bruce Fields [this message]
2012-09-05 20:55 ` [RFC PATCH 06/13] locks: introduce new FL_DELEG lock flag J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 07/13] locks: implement delegations J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 08/13] namei: minor vfs_unlink cleanup J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 09/13] locks: break delegations on unlink J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 10/13] locks: helper functions for delegation breaking J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 11/13] locks: break delegations on rename J. Bruce Fields
2012-09-05 20:55 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 12/13] locks: break delegations on link J. Bruce Fields
2012-09-05 21:02 ` J. Bruce Fields
2012-09-06 11:01 ` Jeff Layton
2012-09-06 13:33 ` J. Bruce Fields
2012-09-06 13:33 ` J. Bruce Fields
2012-09-05 20:55 ` [RFC PATCH 13/13] locks: break delegations on any attribute modification J. Bruce Fields
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120910143541.GC30136@fieldses.org \
--to=bfields@fieldses.org \
--cc=bfields@redhat.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=yan@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.