From patchwork Tue Jul 21 16:27:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11676109 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6423813B6 for ; Tue, 21 Jul 2020 16:30:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C24420771 for ; Tue, 21 Jul 2020 16:30:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Mdh/cnjx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730508AbgGUQad (ORCPT ); Tue, 21 Jul 2020 12:30:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728956AbgGUQ2Y (ORCPT ); Tue, 21 Jul 2020 12:28:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FB6CC0619DA; Tue, 21 Jul 2020 09:28:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=CAvAtIIkzm3fHK0HKBHFJbCbWuSjjmsX8Z35+03m94I=; b=Mdh/cnjxeP+90d07hvT42e5OTb SJehNGJ6lRo0gUibMHZui+5L4KxWRhiKXXeDSyxnxjvjtgJufGqVpmwF0hNJKJok0txYSSY5zeSja BzPgZVL5goWPwRRBMneQx+hrpJ+CCcnOxv0/sXtzo7mQ5uqYsMVenTzEgVjOTPJtj1yKQvsE9nPh0 ok9L2Qtf4ECGPe/KQwS+jHFFMPx/Ni6A4bg+7mflmvmRE4yotLpgKiQqgFviHL/Pmz8VoD7WnMMKm wFimCYe9PpiuQvCJmkTRLeNFihucuLCpP4RYde/WBuuDoJOa5C0BAcnHewgqtYVPDSxrIcBiR/fOH 1nRQArcw==; Received: from [2001:4bb8:18c:2acc:5b1c:6483:bd6d:e406] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jxv7s-0007Qw-FT; Tue, 21 Jul 2020 16:28:21 +0000 From: Christoph Hellwig To: Al Viro , Linus Torvalds Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH 01/24] fs: refactor do_mount Date: Tue, 21 Jul 2020 18:27:55 +0200 Message-Id: <20200721162818.197315-2-hch@lst.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200721162818.197315-1-hch@lst.de> References: <20200721162818.197315-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Factor out a path_mount helper that takes a struct path * instead of the actual file name. This will allow to convert the init and devtmpfs code to properly mount based on a kernel pointer instead of relying on the implicit set_fs(KERNEL_DS) during early init. Signed-off-by: Christoph Hellwig --- fs/namespace.c | 67 ++++++++++++++++++++++++++------------------------ 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index f30ed401cc6d7a..6f8234f74bed90 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3115,12 +3115,11 @@ char *copy_mount_string(const void __user *data) * Therefore, if this magic number is present, it carries no information * and must be discarded. */ -long do_mount(const char *dev_name, const char __user *dir_name, +static int path_mount(const char *dev_name, struct path *path, const char *type_page, unsigned long flags, void *data_page) { - struct path path; unsigned int mnt_flags = 0, sb_flags; - int retval = 0; + int ret; /* Discard magic */ if ((flags & MS_MGC_MSK) == MS_MGC_VAL) @@ -3133,19 +3132,13 @@ long do_mount(const char *dev_name, const char __user *dir_name, if (flags & MS_NOUSER) return -EINVAL; - /* ... and get the mountpoint */ - retval = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path); - if (retval) - return retval; - - retval = security_sb_mount(dev_name, &path, - type_page, flags, data_page); - if (!retval && !may_mount()) - retval = -EPERM; - if (!retval && (flags & SB_MANDLOCK) && !may_mandlock()) - retval = -EPERM; - if (retval) - goto dput_out; + ret = security_sb_mount(dev_name, path, type_page, flags, data_page); + if (ret) + return ret; + if (!may_mount()) + return -EPERM; + if ((flags & SB_MANDLOCK) && !may_mandlock()) + return -EPERM; /* Default to relatime unless overriden */ if (!(flags & MS_NOATIME)) @@ -3172,7 +3165,7 @@ long do_mount(const char *dev_name, const char __user *dir_name, ((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME | MS_STRICTATIME)) == 0)) { mnt_flags &= ~MNT_ATIME_MASK; - mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK; + mnt_flags |= path->mnt->mnt_flags & MNT_ATIME_MASK; } sb_flags = flags & (SB_RDONLY | @@ -3185,22 +3178,32 @@ long do_mount(const char *dev_name, const char __user *dir_name, SB_I_VERSION); if ((flags & (MS_REMOUNT | MS_BIND)) == (MS_REMOUNT | MS_BIND)) - retval = do_reconfigure_mnt(&path, mnt_flags); - else if (flags & MS_REMOUNT) - retval = do_remount(&path, flags, sb_flags, mnt_flags, - data_page); - else if (flags & MS_BIND) - retval = do_loopback(&path, dev_name, flags & MS_REC); - else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) - retval = do_change_type(&path, flags); - else if (flags & MS_MOVE) - retval = do_move_mount_old(&path, dev_name); - else - retval = do_new_mount(&path, type_page, sb_flags, mnt_flags, - dev_name, data_page); -dput_out: + return do_reconfigure_mnt(path, mnt_flags); + if (flags & MS_REMOUNT) + return do_remount(path, flags, sb_flags, mnt_flags, data_page); + if (flags & MS_BIND) + return do_loopback(path, dev_name, flags & MS_REC); + if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) + return do_change_type(path, flags); + if (flags & MS_MOVE) + return do_move_mount_old(path, dev_name); + + return do_new_mount(path, type_page, sb_flags, mnt_flags, dev_name, + data_page); +} + +long do_mount(const char *dev_name, const char __user *dir_name, + const char *type_page, unsigned long flags, void *data_page) +{ + struct path path; + int ret; + + ret = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path); + if (ret) + return ret; + ret = path_mount(dev_name, &path, type_page, flags, data_page); path_put(&path); - return retval; + return ret; } static struct ucounts *inc_mnt_namespaces(struct user_namespace *ns)