Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759437Ab2FGByO (ORCPT ); Wed, 6 Jun 2012 21:54:14 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:36754 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756870Ab2FGByM (ORCPT ); Wed, 6 Jun 2012 21:54:12 -0400 Date: Thu, 7 Jun 2012 02:54:10 +0100 From: Al Viro To: Linus Torvalds Cc: Dave Jones , Linux Kernel , Miklos Szeredi , Jan Kara , Peter Zijlstra Subject: Re: processes hung after sys_renameat, and 'missing' processes Message-ID: <20120607015410.GG30000@ZenIV.linux.org.uk> References: <20120606230040.GA18089@redhat.com> <20120606235403.GC30000@ZenIV.linux.org.uk> <20120607002914.GB22223@redhat.com> <20120607011915.GA17566@redhat.com> <20120607012900.GE30000@ZenIV.linux.org.uk> <20120607013149.GF30000@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1067 Lines: 24 On Wed, Jun 06, 2012 at 06:45:35PM -0700, Linus Torvalds wrote: > On Wed, Jun 6, 2012 at 6:31 PM, Al Viro wrote: > > > > And you want to check i_mutex on old parent, not the file being moved > > itself. ?IOW, the second one should be > > > > if (dentry->d_parent != dentry) > > ? ? ? ?WARN_ON_ONCE(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); > > Do you even need the "dentry->d_parent != dentry" test? When do we > even rename root dentries? Root of the filesystem - never; root of disconnected subtree - sure, that's how they become connected to the tree. See d_materialize_unique(), for example... BTW, I really need more coffee - those checks belong in __d_move(), not d_move(); aforementioned d_materialize_unique() doesn't use d_move(), it calls __d_move() directly. Sorry. -- 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/