From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757515Ab2HUMkf (ORCPT ); Tue, 21 Aug 2012 08:40:35 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:2347 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754350Ab2HUMkd (ORCPT ); Tue, 21 Aug 2012 08:40:33 -0400 Message-ID: <503381B0.7040705@parallels.com> Date: Tue, 21 Aug 2012 16:40:16 +0400 From: Pavel Emelyanov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120209 Thunderbird/10.0.1 MIME-Version: 1.0 To: "J. Bruce Fields" CC: "Aneesh Kumar K.V" , Al Viro , Cyrill Gorcunov , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , Alexey Dobriyan , Andrew Morton , James Bottomley , Matthew Helsley Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper References: <20120820183225.GB4911@fieldses.org> <20120820190606.GE27443@moon> <20120820193204.GD5779@fieldses.org> <50335261.5090504@parallels.com> <87wr0sle4v.fsf@skywalker.in.ibm.com> <503367CB.9080609@parallels.com> <20120821105424.GA7670@moon> <50336C51.60501@parallels.com> <20120821121155.GC9483@fieldses.org> <50337D87.90607@parallels.com> <20120821122908.GE9483@fieldses.org> In-Reply-To: <20120821122908.GE9483@fieldses.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>> Al, Bruce, Aneesh, >>>> >>>> What if we calculate the handle at the time we do have struct path at hands (i.e. >>>> when we create the inotify) and store it on the inotify structure purely to be >>>> shown later in proc. Would that be acceptable? >>> >>> Was it the lack of a dentry that was really the problem? I thought it >>> was just the fact that not all filesystems support filehandles. >> >> Initial problem -- we don't know what is being watched by an inotify fd. >> >> Having a dentry somewhere was the 1st attempt to solve this -- keep a path >> in inotify and show it when required. It doesn't work since holding a ref on >> path changes the behavior of watched inode (we cannot rename/unlink/remount >> it the same way as we could before patching the kernel). > > OK. So if you don't mind the fact that there are filesystems with > inotify support but not filehandle support, then I think generating a > filehandle early as you describe would work. I guess it's a little more > memory per watched inode. Great! Thanks, Bruce, we'll rework the patch accordingly :) > --b. > . > Thanks, Pavel