Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757114AbZDRDMW (ORCPT ); Fri, 17 Apr 2009 23:12:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753614AbZDRDMM (ORCPT ); Fri, 17 Apr 2009 23:12:12 -0400 Received: from mtoichi11.ns.itscom.net ([219.110.2.181]:65010 "EHLO mtoichi11.ns.itscom.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753427AbZDRDMM (ORCPT ); Fri, 17 Apr 2009 23:12:12 -0400 From: hooanon05@yahoo.co.jp Subject: Re: [PATCH] Fix i_mutex handling in nfsd readdir. To: David Woodhouse Cc: Al Viro , bfields@citi.umich.edu, hch@infradead.org, "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" In-Reply-To: <1240013753.21423.86.camel@macbook.infradead.org> References: <8036.1237474444@jrobl> <1237475837.16359.106.camel@macbook.infradead.org> <8913.1237476890@jrobl> <1239960739.3428.33.camel@macbook.infradead.org> <20090417193233.GM26366@ZenIV.linux.org.uk> <1240006620.19059.41.camel@macbook.infradead.org> <20090417224350.GN26366@ZenIV.linux.org.uk> <20090417225306.GO26366@ZenIV.linux.org.uk> <1240013753.21423.86.camel@macbook.infradead.org> Date: Sat, 18 Apr 2009 12:11:54 +0900 Message-ID: <905.1240024314@jrobl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1001 Lines: 28 David Woodhouse: > This patch fixes it by locking the directory's i_mutex again before > calling the filldir functions. The original deadlocks which commit > 14f7dd63 was designed to avoid are still avoided, because they were due > to fs-internal locking, not i_mutex. ::: > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -1248,6 +1248,8 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) > int err; > struct qstr this; > > + WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); > + > err = __lookup_one_len(name, &this, base, len); I'd suggest this checking is done only when CONFIG_DEBUG_KERNEL (or something) is enabled. Because unconditional checking costs high for the well-reviewed lookup code. J. R. Okajima -- 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/