Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262044AbVBPPfq (ORCPT ); Wed, 16 Feb 2005 10:35:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262045AbVBPPfp (ORCPT ); Wed, 16 Feb 2005 10:35:45 -0500 Received: from wombat.indigo.net.au ([202.0.185.19]:16140 "EHLO wombat.indigo.net.au") by vger.kernel.org with ESMTP id S262044AbVBPPff (ORCPT ); Wed, 16 Feb 2005 10:35:35 -0500 Date: Wed, 16 Feb 2005 23:20:21 +0800 (WST) From: raven@themaw.net To: Jan Blunck cc: viro@parcelfarce.linux.theplanet.co.uk, Linux-Kernel Mailing List , Andrew Morton , Martin Schwidefsky Subject: Re: [PATCH] dcache d_drop() bug fix / __d_drop() use fix In-Reply-To: <421355A4.6000305@tu-harburg.de> Message-ID: References: <421355A4.6000305@tu-harburg.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam, SpamAssassin (score=-101.1, required 8, EMAIL_ATTRIBUTION, IN_REP_TO, NO_REAL_NAME, PATCH_UNIFIED_DIFF, QUOTED_EMAIL_TEXT, RCVD_IN_ORBS, RCVD_IN_OSIRUSOFT_COM, REFERENCES, REPLY_WITH_QUOTES, USER_AGENT_PINE, USER_IN_WHITELIST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1370 Lines: 41 On Wed, 16 Feb 2005, Jan Blunck wrote: > This is a re-submission of the patch I sent about a month ago. > > While working on my code I realized that d_drop() might race against > __d_lookup(). __d_drop() (which is called by d_drop() after acquiring the > dcache_lock) is accessing dentry->d_flags to set the DCACHE_UNHASHED flag. > This shouldn't be done without holding dentry->d_lock, like stated in > dcache.h: > > struct dentry { > ... > unsigned int d_flags; /* protected by d_lock */ > ... > }; > > Therefore d_drop() must acquire the dentry->d_lock. Likewise every use of > __d_drop() must acquire that lock. > > This patch fixes d_drop() and every grep'able __d_drop() use. This patch is > against today's http://linux.bkbits.net/linux-2.5. > For my part, in autofs4, I would prefer: --- linux-2.6.9/fs/autofs4/root.c.d_lock 2005-02-16 23:15:18.000000000 +0800 +++ linux-2.6.9/fs/autofs4/root.c 2005-02-16 23:15:35.000000000 +0800 @@ -621,7 +621,7 @@ spin_unlock(&dcache_lock); return -ENOTEMPTY; } - __d_drop(dentry); + d_drop(dentry); spin_unlock(&dcache_lock); dput(ino->dentry); - 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/