From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Kent Subject: Re: [announce] vfs-scale git tree update Date: Thu, 13 Jan 2011 09:48:33 +0800 Message-ID: <1294883313.2757.5.camel@perseus> References: <20110107075831.GA14915@amd> <1294763679.2435.72.camel@doink> <1294768668.2435.177.camel@doink> <1294804776.2821.4.camel@perseus> <1294807279.2821.9.camel@perseus> <1294809426.2821.20.camel@perseus> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Linus Torvalds , aelder@sgi.com, Nick Piggin , Al Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Nick Piggin Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, 2011-01-13 at 12:01 +1100, Nick Piggin wrote: > On Wed, Jan 12, 2011 at 4:17 PM, Ian Kent wrote: > > On Wed, 2011-01-12 at 12:41 +0800, Ian Kent wrote: > >> On Tue, 2011-01-11 at 20:06 -0800, Linus Torvalds wrote: > >> > On Tue, Jan 11, 2011 at 7:59 PM, Ian Kent wrote: > > >> > > Yeah, a hangover from changes done over time. > >> > > Not setting the dentry op in ->lookup() should fix this. > >> > > >> > Alex, care to test just removing the d_set_d_op() call from autofs4_lookup()? > >> > > >> > (That code is a bit scary, though - it explicitly makes it a negative > >> > dentry with a d_instantiate(dentry, NULL), and then hides the inode > >> > information away separately. Scary scary) > >> > >> Yeah, but the expire to mount races with autofs are difficult to handle > >> and this approach has worked well under heavy stress testing. It's true > >> that this would almost certainly be bad for a file system that supported > >> a full range of functionality but that's not so for autofs. > > > > I think I have to partly take this back. > > With Nick's recent vfs-scale patches this may not be OK any more since > > the dcache_lock has gone away and, at first glance, it looks like the > > added autofs4_lock spin lock doesn't provide the needed protection. > > Hm, what are the concurrencies that you need protection from? Ha, I think I'm wrong about this, after looking more closely at this I'm struggling to see why autofs4_lock is needed at all.