From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [PATCH] autofs4 - use lookup access intent to support recursive bind mounts Date: Mon, 28 Apr 2008 08:05:14 +0100 Message-ID: <20080428070514.GC5882@ZenIV.linux.org.uk> References: <20080428062213.GB5882@ZenIV.linux.org.uk> <1209364705.3243.1.camel@raven.themaw.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , Kernel Mailing List , autofs mailing list , linux-fsdevel To: Ian Kent Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:46514 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763844AbYD1HFR (ORCPT ); Mon, 28 Apr 2008 03:05:17 -0400 Content-Disposition: inline In-Reply-To: <1209364705.3243.1.camel@raven.themaw.net> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, Apr 28, 2008 at 02:38:25PM +0800, Ian Kent wrote: > > On Mon, 2008-04-28 at 07:22 +0100, Al Viro wrote: > > On Mon, Apr 28, 2008 at 02:14:54PM +0800, Ian Kent wrote: > > > > > > Hi Andrew, > > > > > > For autofs maps that recursively reference other map entries in their > > > mount point path we need to ensure that these mounts are performed > > > prior to the current mount request being done. We've used the access > > > system call, made just prior to performing the mount, to make this > > > happen. In the case of bind mounts, however, the lookup flags in > > > the path walk don't trigger a mount. To do this we need to also > > > trigger a mount when we see the LOOKUP_ACCESS flag. > > > > That's too fscking bad, since ->lookup() is about to lose access to > > nameidata *and* flags for anything but the last step. IOW, we'll need > > cleaner solution... > > Spell it out for me please! ->lookup() and friends are going to stop getting struct nameidata *. ->follow_link() obviously will keep it; ->d_revalidate() should lose the sucker, but we might have to split it in two methods (which is probably what'll be needed in your case). At the same time struct open_intent is going to die, BTW, but that won't matter for autofs, AFAICT.