public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: viro@parcelfarce.linux.theplanet.co.uk
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
	Thomas Moestl <moestl@ibr.cs.tu-bs.de>,
	linux-kernel@vger.kernel.org
Subject: Re: umount() and NFS races in 2.4.26
Date: Sun, 11 Jul 2004 01:32:40 +0100	[thread overview]
Message-ID: <20040711003240.GS12308@parcelfarce.linux.theplanet.co.uk> (raw)
In-Reply-To: <1089495528.5406.10.camel@lade.trondhjem.org>

On Sat, Jul 10, 2004 at 04:38:48PM -0500, Trond Myklebust wrote:
 
> Known problem, but a fix is not trivial since the unlink() procedure
> does not take a nameidata structure argument (which would be needed in
> order to figure out which vfs_mount struct to mntget()).

Why the hell would you need a vfsmount for that?  You want to duplicate
an active reference to superblock and you want it to be dropped later.
Which means atomic_inc(&sb->s_active) and kill_super(sb) resp.

NFS itself has a right to do that - we know that caller of ->unlink()
is holding a reference to vfsmount, so there's an active reference
that won't go away until nfs_unlink() is finished.

Filesystem code can hold active references to superblocks of given type,
provided that it takes care to drop them eventually on its own...

  reply	other threads:[~2004-07-11  0:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-08 18:07 umount() and NFS races in 2.4.26 Thomas Moestl
2004-07-09 14:32 ` Marcelo Tosatti
2004-07-10 21:38   ` Trond Myklebust
2004-07-11  0:32     ` viro [this message]
2004-07-10  6:57 ` raven
2004-07-10 15:25   ` [autofs] " Greg Banks
2004-07-10 18:25     ` Thomas Moestl
2004-07-10 18:19   ` Thomas Moestl
2004-07-10 19:25     ` raven
2004-07-10 19:50       ` Thomas Moestl
2004-07-11 10:16     ` raven
  -- strict thread matches above, loose matches on Subject: below --
2004-07-09 15:00 James Pearson

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=20040711003240.GS12308@parcelfarce.linux.theplanet.co.uk \
    --to=viro@parcelfarce.linux.theplanet.co.uk \
    --cc=linux-kernel@vger.kernel.org \
    --cc=marcelo.tosatti@cyclades.com \
    --cc=moestl@ibr.cs.tu-bs.de \
    --cc=trond.myklebust@fys.uio.no \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox