Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758514AbYCYSMh (ORCPT ); Tue, 25 Mar 2008 14:12:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753211AbYCYSM3 (ORCPT ); Tue, 25 Mar 2008 14:12:29 -0400 Received: from styx.suse.cz ([82.119.242.94]:48566 "EHLO mail.suse.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752846AbYCYSM3 (ORCPT ); Tue, 25 Mar 2008 14:12:29 -0400 Date: Tue, 25 Mar 2008 19:12:27 +0100 From: Jan Kara To: Andrew Morton Cc: David Chinner , Fengguang Wu , linux-kernel@vger.kernel.org Subject: [PATCH] vfs: Fix lock inversion in drop_pagecache_sb() Message-ID: <20080325181227.GE5125@duck.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1499 Lines: 49 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... 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/