From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: Re: Q: NFSD readdir in linux-2.6.28 Date: Fri, 17 Apr 2009 23:55:46 +0100 Message-ID: <1240008946.21423.18.camel@macbook.infradead.org> References: <8036.1237474444@jrobl> <1237475837.16359.106.camel@macbook.infradead.org> <8913.1237476890@jrobl> <1239960739.3428.33.camel@macbook.infradead.org> <20090417193233.GM26366@ZenIV.linux.org.uk> <1240006620.19059.41.camel@macbook.infradead.org> <20090417224350.GN26366@ZenIV.linux.org.uk> <20090417225306.GO26366@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: hooanon05@yahoo.co.jp, hch@infradead.org, "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" To: Al Viro Return-path: Received: from casper.infradead.org ([85.118.1.10]:39507 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759487AbZDQWzw (ORCPT ); Fri, 17 Apr 2009 18:55:52 -0400 In-Reply-To: <20090417225306.GO26366@ZenIV.linux.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 2009-04-17 at 23:53 +0100, Al Viro wrote: > On Fri, Apr 17, 2009 at 11:43:50PM +0100, Al Viro wrote: > > On Fri, Apr 17, 2009 at 11:17:00PM +0100, David Woodhouse wrote: > > > It sounds like the better answer is to just make sure i_mutex is held > > > when nfsd_buffered_readdir() calls back into the provided filldir > > > function (we could do it in the various filldir functions themselves, > > > _if_ they call lookup_one_len(), but I think I prefer it this way -- > > > it's simpler). Patch below for comment. > > > > Umm... I can live with that, assuming that we don't have callbacks > > that take i_mutex themselves. AFAICS, everything we call there is > > either obviously not touching i_mutex or is already called while we > > hold i_mutex elsewhere, but I'd appreciate if somebody actually > > tested that sucker for different versions of protocol... > > BTW, why mess with taking i_mutex inside the inner loop and not > immediately around it? Just to avoid making spaghetti of the bail-out cases, really. I did consider it (it wouldn't be _that_ bad), but figured that it wasn't such a bad thing if we don't hog the lock. -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation