From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from psmtp.com (na3sys010amx179.postini.com [74.125.245.179])
	by kanga.kvack.org (Postfix) with SMTP id 98D8E6B0083
	for <linux-mm@kvack.org>; Fri,  9 Mar 2012 04:51:39 -0500 (EST)
Date: Fri, 9 Mar 2012 10:51:35 +0100
From: Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 5/9] writeback: introduce the pageout work
Message-ID: <20120309095135.GC21038@quack.suse.cz>
References: <20120228160403.9c9fa4dc.akpm@linux-foundation.org>
 <20120301123640.GA30369@localhost>
 <20120301163837.GA13104@quack.suse.cz>
 <20120302044858.GA14802@localhost>
 <20120302095910.GB1744@quack.suse.cz>
 <20120302103951.GA13378@localhost>
 <20120302115700.7d970497.akpm@linux-foundation.org>
 <20120303135558.GA9869@localhost>
 <1331135301.32316.29.camel@sauron.fi.intel.com>
 <20120309073113.GA5337@localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20120309073113.GA5337@localhost>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>, Andrew Morton <akpm@linux-foundation.org>, Jan Kara <jack@suse.cz>, Greg Thelen <gthelen@google.com>, Ying Han <yinghan@google.com>, "hannes@cmpxchg.org" <hannes@cmpxchg.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan.kim@gmail.com>, Linux Memory Management List <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Adrian Hunter <adrian.hunter@intel.com>

  Hello,

On Thu 08-03-12 23:31:13, Wu Fengguang wrote:
> On Wed, Mar 07, 2012 at 05:48:21PM +0200, Artem Bityutskiy wrote:
> > On Sat, 2012-03-03 at 21:55 +0800, Fengguang Wu wrote:
> > >   13   1125  /c/linux/fs/ubifs/file.c <<do_truncation>>   <===== deadlockable
> > 
> > Sorry, but could you please explain once again how the deadlock may
> > happen?
> 
> Sorry I confused ubifs do_truncation() with the truncate_inode_pages()
> that may be called from iput().
> 
> The once suspected deadlock scheme is when the flusher thread calls
> the final iput:
> 
>         flusher thread
>           iput_final
>             <some ubifs function>
>               ubifs_budget_space
>                 shrink_liability
>                   writeback_inodes_sb
>                     writeback_inodes_sb_nr
>                       bdi_queue_work
>                       wait_for_completion  => end up waiting for the flusher itself
> 
> However I cannot find any ubifs functions to form the above loop, so
> ubifs should be safe for now.
  Yeah, me neither but I also failed to find a place where
ubifs_evict_inode() truncates inode space when deleting the inode... Artem?

									Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>