From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Subject: Re: [RFC][PATCH] Add a dentry op to handle automounting rather than abusing follow_link Date: Thu, 22 Jul 2010 16:33:13 +0100 Message-ID: <20204.1279812793@redhat.com> References: <20100722145738.GA5752@amd> <20100722041554.GB3446@amd> <27282.1279058150@redhat.com> <30811.1279802187@redhat.com> Cc: dhowells@redhat.com, viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Nick Piggin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:13713 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754762Ab0GVPdV (ORCPT ); Thu, 22 Jul 2010 11:33:21 -0400 In-Reply-To: <20100722145738.GA5752@amd> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Nick Piggin wrote: > I think you have it the wrong way around. If you wanted to call the > automount code, you would have incremented d_mounted. Why? d_mounted indicates how many things are mounted on a dentry, doesn't it? Before the automounter is invoked there isn't anything mounted there. > Those that don't care wouldn't set ->follow_mount though. Following a mount > is a fairly heavy operation already, it does take a global lock (before vfs > scalability patches, anyway). I wonder if we could do it with a lock on vfsmount instead and use mnt_mounts to find it. > I like the flexibility of doing one's own ->follow_mount, although Al might > object to allowing filesystems to follow mounts in ways that are not > published to the core namespace structures. But why would you want to delegate mountpoint traversal to the filesystem? David