From: Al Viro <viro@ZenIV.linux.org.uk>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
". James Morris" <jmorris@namei.org>,
linux-security-module@vger.kernel.org,
linux-kernel <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
David Miller <davem@davemloft.net>
Subject: Re: deferring __fput()
Date: Mon, 25 Jun 2012 14:53:57 +0100 [thread overview]
Message-ID: <20120625135357.GV14083@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1340630396.2507.66.camel@laptop>
On Mon, Jun 25, 2012 at 03:19:56PM +0200, Peter Zijlstra wrote:
> > I'll need to reread that thread to comment on the specifics (had been too long ago; I don't
> > remember the details), but... See Linus' objections to full-async fput() circa this April
> > or March. There's a reason why this patchset uses task_work_add() whenever possible.
>
> Ok, I'll try and find that thread, so the advantage of task_work_add()
> is that you'll keep the work in the task that caused it wherever
> possible, right -- provided its actually sitll around.
>
> If we make fput() deferable in general we'll be sure to grow some 'fun'
> cases. So are we going to add a sync against unmount someplace to avoid
> these un-expected -EBUSY things?
No. We are not. And I don't care how tasty some application might be -
this way madness lies. If you have _anything_ doing async fput() (which is
perfectly possible with the current mainline), you have to live with the
fact that yes, filesystem will be busy while your mechanism, whatever it
might be, is in use.
BTW, you do realize that delayed fput() may mean delayed fs shutdown?
Think of umount -l while you have an opened file...
prev parent reply other threads:[~2012-06-25 13:54 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-22 12:44 deferring __fput() Mimi Zohar
2012-06-23 9:20 ` Al Viro
2012-06-23 19:45 ` Al Viro
2012-06-23 20:38 ` Oleg Nesterov
2012-06-23 21:01 ` Al Viro
2012-06-23 21:11 ` Al Viro
2012-06-24 4:16 ` Al Viro
2012-06-24 10:09 ` Al Viro
2012-06-24 16:54 ` Oleg Nesterov
2012-06-24 15:33 ` Oleg Nesterov
2012-06-25 6:03 ` Al Viro
2012-06-25 15:18 ` Oleg Nesterov
2012-06-27 18:37 ` [PATCH 0/4] Was: " Oleg Nesterov
2012-06-27 18:37 ` [PATCH 1/4] task_work: use the single-linked list to shrink sizeof(task_work) Oleg Nesterov
2012-06-27 18:37 ` [PATCH 2/4] task_work: don't rely on PF_EXITING Oleg Nesterov
2012-06-27 18:38 ` [PATCH 3/4] task_work: deal with task_work callbacks adding more work Oleg Nesterov
2012-06-27 18:38 ` [PATCH 4/4] task_work: kill task_work->data Oleg Nesterov
2012-06-27 19:05 ` Oleg Nesterov
2012-06-28 4:38 ` [PATCH 0/4] Was: deferring __fput() Al Viro
2012-06-28 16:22 ` Oleg Nesterov
2012-06-28 16:45 ` Oleg Nesterov
2012-06-30 6:24 ` Al Viro
2012-06-30 17:41 ` Oleg Nesterov
2012-06-29 5:30 ` Mimi Zohar
2012-06-29 8:33 ` Al Viro
2012-06-29 13:02 ` Mimi Zohar
2012-06-29 17:41 ` Al Viro
2012-06-29 21:38 ` Mimi Zohar
2012-06-29 23:56 ` Mimi Zohar
2012-06-30 5:02 ` Al Viro
2012-07-01 19:50 ` Mimi Zohar
2012-07-01 20:57 ` Al Viro
2012-07-02 1:46 ` Mimi Zohar
2012-07-02 3:43 ` Al Viro
2012-07-02 5:11 ` Al Viro
2012-07-02 11:49 ` Mimi Zohar
2012-07-02 12:02 ` Al Viro
2012-07-02 13:01 ` Mimi Zohar
2012-07-02 13:33 ` Al Viro
2012-07-02 14:50 ` Mimi Zohar
2012-08-21 13:05 ` [PATCH] task_work: add a scheduling point in task_work_run() Eric Dumazet
2012-08-21 20:37 ` Mimi Zohar
2012-08-21 21:32 ` Eric Dumazet
2012-08-22 3:13 ` Mimi Zohar
2012-08-22 5:27 ` Michael Wang
2012-08-22 5:38 ` Al Viro
2012-06-23 20:57 ` deferring __fput() Al Viro
2012-06-23 21:33 ` Al Viro
2012-06-24 15:20 ` Oleg Nesterov
2012-06-24 18:11 ` Oleg Nesterov
2012-06-25 12:03 ` Peter Zijlstra
2012-06-25 12:14 ` Al Viro
2012-06-25 13:19 ` Peter Zijlstra
2012-06-25 13:53 ` Al Viro [this message]
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