From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from relay.parallels.com ([195.214.232.42]:46097 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787Ab2LKO61 convert rfc822-to-8bit (ORCPT ); Tue, 11 Dec 2012 09:58:27 -0500 Message-ID: <50C749E0.4040107@parallels.com> Date: Tue, 11 Dec 2012 18:57:36 +0400 From: Stanislav Kinsbursky MIME-Version: 1.0 To: Al Viro CC: "J. Bruce Fields" , , , Subject: Re: [PATCH 2/6] nfsd: swap fs root in NFSd kthreads References: <20121206153204.30693.11408.stgit@localhost.localdomain> <20121206153447.30693.54128.stgit@localhost.localdomain> <20121210202842.GB17350@fieldses.org> <50C73C60.8060405@parallels.com> <20121211145443.GH4939@ZenIV.linux.org.uk> In-Reply-To: <20121211145443.GH4939@ZenIV.linux.org.uk> Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: 11.12.2012 18:54, Al Viro пишет: > On Tue, Dec 11, 2012 at 06:00:00PM +0400, Stanislav Kinsbursky wrote: >> 11.12.2012 00:28, J. Bruce Fields ??????????: >>> On Thu, Dec 06, 2012 at 06:34:47PM +0300, Stanislav Kinsbursky wrote: >>>> NFSd does lookup. Lookup is done starting from current->fs->root. >>>> NFSd is a kthread, cloned by kthreadd, and thus have global (but luckely >>>> unshared) root. >>>> So we have to swap root to those, which process, started NFSd, has. Because >>>> that process can be in a container with it's own root. >>> >>> This doesn't sound right to me. >>> >>> Which lookups exactly do you see being done relative to >>> current->fs->root ? >>> >> >> Ok, you are right. I was mistaken here. >> This is not a exactly lookup, but d_path() problem in svc_export_request(). >> I.e. without root swapping, d_path() will give not local export path (like "/export") >> but something like this "/root/containers_root/export". > > Now, *that* is a different story (and makes some sense). Take a look > at __d_path(), please. You don't need to set ->fs->root to get d_path() > equivalent relative to given point. > Thanks, Al. But __d_path() is not exported and this code is called from NFSd module. Is it suitable for you to export __d_path()? -- Best regards, Stanislav Kinsbursky