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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_NEOMUTT autolearn=unavailable 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 64F88C4646B for ; Fri, 21 Jun 2019 09:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3DFD121537 for ; Fri, 21 Jun 2019 09:48:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=brauner.io header.i=@brauner.io header.b="GV35dJjs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726846AbfFUJsD (ORCPT ); Fri, 21 Jun 2019 05:48:03 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:33928 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726309AbfFUJsC (ORCPT ); Fri, 21 Jun 2019 05:48:02 -0400 Received: by mail-wr1-f67.google.com with SMTP id k11so5950999wrl.1 for ; Fri, 21 Jun 2019 02:48:00 -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=3sR1fsmOSmMKPt8ApFzplMSFtr7yaH3nHZVGcmffx0Q=; b=GV35dJjszA2zyHawIt2qliimXzvnUf0QFh4LXG6Qrac1iPxZRxa0EV3PU1oiQ3rqgI w2dWQImPU9+JzAZD4UHzer/YglnG9xfKpla/T1B1o3XfW6P++B4wKJzaBkKBpyDIpaxp fOzqNdhAXv1JUkvFNBoXaEIcNVqoz9UGPppTawtHbf+ElY2DsjcTpUutsbyyv5HjJiDs sa023duB/cjPXzrkXUROEYjvu0yhO6SRf6I3fDpLNculp9vqjPgQ/yWWGFW4LU9gYOjK X0c6PHgiC1AOvAcu8hn5SrY2wHe3+MnG3/DQ1W6owW76RuaKyWXi8d0RJHNHYpnylfJN cJBw== 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=3sR1fsmOSmMKPt8ApFzplMSFtr7yaH3nHZVGcmffx0Q=; b=ceAnvmZy04CRXiowOYg4SQTcqf2jcg/0iyN7395Rvl3Gpnxnd+5I2XVvYEqGNSo/bX 3BN+ddXG9xEcKzUrsxo1DSTurHgqADd0bsT7YK/4wNG4QUrXvZ0KCX5lzOO5fg8ZBxtg LFLUML4644/TPB9bBFFH4drFFMb5VS93aQAM3m2u3Uos8u3Y2Hvpdne/8ZN68drkaKge Z27zz/P2TXEnebvLN8uUeDEOUMbi5Der4PobpgQf10FuT0/Nl/HiWhM/XRAeJ0JtCQhn Mal9QtvI/cGzu+x2nU+7iLEHNi+8daolLfe0EanSF3pAUooKWwLlWYp3dADIuCWKGsoh MpcQ== X-Gm-Message-State: APjAAAUi7rFpnyrk5yMzmbCdcxBAwUuOPnRIB0DGMhmkkHnVpeWwl5TN XaAxQscepJjJYHjQP6HjaebN5Q== X-Google-Smtp-Source: APXvYqwCnu1hdf21Y7luHVjdpSkHECqDwwuknTo9xsscjgheBeySu0sil9T4YyQsIlO/8EnrX+BBiw== X-Received: by 2002:a5d:62c9:: with SMTP id o9mr60848301wrv.186.1561110480029; Fri, 21 Jun 2019 02:48:00 -0700 (PDT) Received: from brauner.io ([212.91.227.56]) by smtp.gmail.com with ESMTPSA id 66sm1941602wma.11.2019.06.21.02.47.59 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 21 Jun 2019 02:47:59 -0700 (PDT) Date: Fri, 21 Jun 2019 11:47:58 +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: <20190621094757.zijugn6cfulmchnf@brauner.io> References: <155905626142.1662.18430571708534506785.stgit@warthog.procyon.org.uk> <155905627927.1662.13276277442207649583.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <155905627927.1662.13276277442207649583.stgit@warthog.procyon.org.uk> User-Agent: NeoMutt/20180716 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, May 28, 2019 at 04:11:19PM +0100, David Howells wrote: > Allow fsinfo() to be used to query the filesystem attached to an fs_context > once a superblock has been created or if it comes from fspick(). > > This is done with something like: > > fd = fsopen("ext4", 0); > ... > fsconfig(fd, fsconfig_cmd_create, ...); > fsinfo(fd, NULL, ...); > > Signed-off-by: David Howells > --- > > fs/fsinfo.c | 30 +++++++++++++++++++++++++++++- > fs/statfs.c | 2 +- > 2 files changed, 30 insertions(+), 2 deletions(-) > > diff --git a/fs/fsinfo.c b/fs/fsinfo.c > index f9a63410e9a2..14db881dd02d 100644 > --- a/fs/fsinfo.c > +++ b/fs/fsinfo.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include > #include "internal.h" > > @@ -315,13 +316,40 @@ static int vfs_fsinfo_path(int dfd, const char __user *filename, > return ret; > } > > +static int vfs_fsinfo_fscontext(struct fs_context *fc, > + struct fsinfo_kparams *params) > +{ > + int ret; > + > + if (fc->ops == &legacy_fs_context_ops) > + return -EOPNOTSUPP; > + > + ret = mutex_lock_interruptible(&fc->uapi_mutex); > + if (ret < 0) > + return ret; > + > + ret = -EIO; > + if (fc->root) { > + struct path path = { .dentry = fc->root }; > + > + ret = vfs_fsinfo(&path, params); > + } > + > + mutex_unlock(&fc->uapi_mutex); > + return ret; > +} > + > 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 f_ops will be set to empty_fops so you'll always end up in the vfs_fsinfo branch. Is that your intention? That means the new mount api doesn't support fsinfo() without using a non-O_PATH fd, right? Why the fallback then? Christian > int ret = -EBADF; > > if (f.file) { > - ret = vfs_fsinfo(&f.file->f_path, params); > + if (f.file->f_op == &fscontext_fops) > + ret = vfs_fsinfo_fscontext(f.file->private_data, > + params); > + else > + ret = vfs_fsinfo(&f.file->f_path, params); > fdput(f); > } > return ret; > diff --git a/fs/statfs.c b/fs/statfs.c > index eea7af6f2f22..b9b63d9f4f24 100644 > --- a/fs/statfs.c > +++ b/fs/statfs.c > @@ -86,7 +86,7 @@ int vfs_statfs(const struct path *path, struct kstatfs *buf) > int error; > > error = statfs_by_dentry(path->dentry, buf); > - if (!error) > + if (!error && path->mnt) > buf->f_flags = calculate_f_flags(path->mnt); > return error; > } >