Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760853AbYCZAot (ORCPT ); Tue, 25 Mar 2008 20:44:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757615AbYCZAol (ORCPT ); Tue, 25 Mar 2008 20:44:41 -0400 Received: from smtp.ustc.edu.cn ([202.38.64.16]:48144 "HELO ustc.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1757407AbYCZAol (ORCPT ); Tue, 25 Mar 2008 20:44:41 -0400 Message-ID: <406492300.07067@ustc.edu.cn> X-EYOUMAIL-SMTPAUTH: wfg@mail.ustc.edu.cn Date: Wed, 26 Mar 2008 08:44:36 +0800 From: Fengguang Wu To: Jan Kara Cc: Andrew Morton , David Chinner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] vfs: Fix lock inversion in drop_pagecache_sb() References: <20080325181227.GE5125@duck.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080325181227.GE5125@duck.suse.cz> X-GPG-Fingerprint: 53D2 DDCE AB5C 8DC6 188B 1CB1 F766 DA34 8D8B 1C6D User-Agent: Mutt/1.5.17 (2007-11-01) Message-Id: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1825 Lines: 58 On Tue, Mar 25, 2008 at 07:12:27PM +0100, Jan Kara wrote: > Fix longstanding lock inversion in drop_pagecache_sb by dropping inode_lock > before calling __invalidate_mapping_pages(). We just have to make sure > inode won't go away from under us by keeping reference to it and putting > the reference only after we have safely resumed the scan of the inode > list. A bit tricky but not too bad... Reviewed-by: Fengguang Wu It's a handy trick to iterate through the list_head :-) I have practiced this in my filecache code, and it works nice. Fengguang > Signed-off-by: Jan Kara > CC: Fengguang Wu > CC: David Chinner > > --- > fs/drop_caches.c | 8 +++++++- > 1 files changed, 7 insertions(+), 1 deletions(-) > > diff --git a/fs/drop_caches.c b/fs/drop_caches.c > index 59375ef..f5aae26 100644 > --- a/fs/drop_caches.c > +++ b/fs/drop_caches.c > @@ -14,15 +14,21 @@ int sysctl_drop_caches; > > static void drop_pagecache_sb(struct super_block *sb) > { > - struct inode *inode; > + struct inode *inode, *toput_inode = NULL; > > spin_lock(&inode_lock); > list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { > if (inode->i_state & (I_FREEING|I_WILL_FREE)) > continue; > + __iget(inode); > + spin_unlock(&inode_lock); > __invalidate_mapping_pages(inode->i_mapping, 0, -1, true); > + iput(toput_inode); > + toput_inode = inode; > + spin_lock(&inode_lock); > } > spin_unlock(&inode_lock); > + iput(toput_inode); > } > > void drop_pagecache(void) > -- > 1.5.2.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/