From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [WTF] ... is going on with current->fs->{root,mnt} accesses in pohmelfs Date: Wed, 10 Feb 2010 16:30:07 +0300 Message-ID: <20100210133007.GA17744@ioremap.net> References: <20100210100428.GL30031@ZenIV.linux.org.uk> <20100210101246.GA3509@ioremap.net> <20100210102422.GM30031@ZenIV.linux.org.uk> <20100210104515.GA6207@ioremap.net> <20100210110011.GN30031@ZenIV.linux.org.uk> <20100210111115.GA8376@ioremap.net> <20100210115938.GO30031@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Al Viro Return-path: Content-Disposition: inline In-Reply-To: <20100210115938.GO30031@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Feb 10, 2010 at 11:59:39AM +0000, Al Viro (viro@ZenIV.linux.org.uk) wrote: > > Let me guess... Mmmm, it was in the yesterday newspaper, I remember. > > Maybe when we chroot somewhere. I meant not mounted fs root, but > > thread's root. > > Why would a filesystem give a damn about the chroot of syscall originator > in the first place? That's the point - it is not needed. > > > Why not use the dentries you've been given by VFS? > > > > At writeback we do not have parents, so must find a path somehow. > > Most of the places do have those just fine and unlike the writeback, > rename et.al. really care which pathname is being dealt with... POHMELFS uses writeback cache also for metadata, so effectively most of such operations are also postponed. Later I turned that off though. > BTW, what prevents writeback vs. rename races? There are proper locks for such operations. -- Evgeniy Polyakov