From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDA98C43613 for ; Fri, 21 Jun 2019 13:28:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEE7B208C3 for ; Fri, 21 Jun 2019 13:28:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=brauner.io header.i=@brauner.io header.b="ePuxoeeN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726145AbfFUN2o (ORCPT ); Fri, 21 Jun 2019 09:28:44 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:35951 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726121AbfFUN2o (ORCPT ); Fri, 21 Jun 2019 09:28:44 -0400 Received: by mail-wr1-f68.google.com with SMTP id n4so5402542wrs.3 for ; Fri, 21 Jun 2019 06:28:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=brauner.io; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=9EMsrpo1moUaH2rHK1LlYi+tUBFSGMr7JAdJB+mRI/g=; b=ePuxoeeNHfTWihZvcOuCDGTjMSQJR2s8+iO36eDnxzA2613uotv2mmvRre4mAoyBTH tpHZUMHF+W/Gl6aVgY2WlMgOi4JGt/7LoReSbjccE3cOlvYGjvQlqV1PSwbqPLsXYiwc Qbty5/DAl6yAmIPjDjKlqz9wHu5liUE2Ezb+Aq99lkDjiz3zaJkziT+iqQ/GDj5N8rzx mlbBbYGt0+pd4MFtLT8gN0NsbWg7B1X3DTL3RWXaHw29eyXy4tbP89E8WacQIkQHmrkC jU3BInZsYTLHfOgK8SwzIPX+iC+yGTzWH01ZETolkrtW4q/J59eqLmHjKW2zLeZZ021t J2uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=9EMsrpo1moUaH2rHK1LlYi+tUBFSGMr7JAdJB+mRI/g=; b=amNG5pWrIgte5FuRFzWs2aiP7AhMFAkJAVvanMdmQmrd3Ub3K49WgQq1oXWCVGJjdO yu3puT9UNObQC+2sG/XoB6+q9FU2E2F4W4kkbrWpKm3PSseGxU1gouWkKjuIIWR867lN MNcjGB70a/YVx2TL3hhFHGqG/qdsvo+H1vX34Rnu2xzQEWxIvqNDw5P6trQJAFZedjmH a1tZNm69JhijsDXP++6X4jc5DWiTHhvDKG3hMkL2K60pYygJ75945v6scg73JZwqpNQv iZKPnbNfpevxRi3VD+6Bn2xNIm6kvyxotwXE6xwbMZpBmYFBcPRlehmlHMvOkh2gVWZv iUDA== X-Gm-Message-State: APjAAAXFNHRwRiSnXTaEhUujzAwEWaevNiYGtgp4FhHgNTnW1XHFzeQG yqO20g9nqoSfBqCARTkatpdABw== X-Google-Smtp-Source: APXvYqz7/r+j2/bz2zXC4bWeBw0/AOUH64ui71bNQocHtMgX5fBuIDo4/VDUKh7gVgVmUFvnOKbPGA== X-Received: by 2002:adf:eacd:: with SMTP id o13mr24607835wrn.91.1561123722303; Fri, 21 Jun 2019 06:28:42 -0700 (PDT) Received: from brauner.io ([212.91.227.56]) by smtp.gmail.com with ESMTPSA id v15sm2867708wrt.25.2019.06.21.06.28.41 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 21 Jun 2019 06:28:41 -0700 (PDT) Date: Fri, 21 Jun 2019 15:28:40 +0200 From: Christian Brauner To: David Howells Cc: viro@zeniv.linux.org.uk, raven@themaw.net, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com Subject: Re: [PATCH 02/25] vfs: Allow fsinfo() to query what's in an fs_context [ver #13] Message-ID: <20190621132839.6ggsppexqfp5htpw@brauner.io> References: <20190621094757.zijugn6cfulmchnf@brauner.io> <155905626142.1662.18430571708534506785.stgit@warthog.procyon.org.uk> <155905627927.1662.13276277442207649583.stgit@warthog.procyon.org.uk> <21652.1561122763@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 21, 2019 at 03:16:04PM +0200, Christian Brauner wrote: > On June 21, 2019 3:12:43 PM GMT+02:00, David Howells wrote: > >Christian Brauner wrote: > > > >> > static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_kparams > >*params) > >> > { > >> > struct fd f = fdget_raw(fd); > >> > >> You're using fdget_raw() which means you want to allow O_PATH fds but > >> below you're checking whether the f_ops correspond to > >> fscontext_fops. If it's an O_PATH > > > >It can't be. The only way to get an fs_context fd is from fsopen() or > >fspick() - neither of which allow O_PATH to be specified. > > > >If you tried to go through /proc/pid/fd with open(O_PATH), I think > >you'd get > >the symlink, not the target. > > Then you should use fdget(), no? :) That is unless you want fsinfo() to be useable on any fd and just fds that are returned from the new mount-api syscalls. Maybe that wasn't clear from my first mail. Is the information returned for: int fd = fsopen()/fspick(); fsinfo(fd); int ofd = open("/", O_PATH); fsinfo(ofd, ...); the same if they refer to the same mount or would they differ? Christian