From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Kent Subject: Re: [PATCH] autofs4 - detect invalid direct mount requests Date: Fri, 20 Jun 2008 21:12:12 +0800 Message-ID: <1213967533.2971.98.camel@raven.themaw.net> References: <20080620051301.9988.94307.stgit@raven.themaw.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Kernel Mailing List , autofs mailing list , linux-fsdevel To: Jeff Moyer Return-path: Received: from out3.smtp.messagingengine.com ([66.111.4.27]:38124 "EHLO out3.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753016AbYFTNNI (ORCPT ); Fri, 20 Jun 2008 09:13:08 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 2008-06-20 at 09:00 -0400, Jeff Moyer wrote: > Ian Kent writes: > > > autofs v5 dierct and offset mounts within an autofs filesystem are > > triggered by existing autofs triger mounts so the mount point dentry > > must be positive. If the mount point dentry is negative then the > > trigger doesn't exist so we can return fail immediately. > > What are the conditions that lead us here in that case? v5 doesn't need to get those dir/otherdir messages that we can't avoid for v4. Basically, attempts to access a non-existent directory in multi-mount tree leads to a negative dentry being sent to the wait queue, but v5 direct and offset mounts must always have an existing (non-negative dentry) directory upon which to mount. This is only relevant for multi-mounts that don't have an explicit multi-mount root so that the lookups occur within the autofs file system. Sorry, I still can't think of a way to avoid this for v4. Ian