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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 8F718C43381 for ; Thu, 21 Mar 2019 11:47:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67CCB218FD for ; Thu, 21 Mar 2019 11:47:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728166AbfCULrp (ORCPT ); Thu, 21 Mar 2019 07:47:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53260 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727829AbfCULrp (ORCPT ); Thu, 21 Mar 2019 07:47:45 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 320CD8123A; Thu, 21 Mar 2019 11:47:45 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-98.rdu2.redhat.com [10.10.121.98]) by smtp.corp.redhat.com (Postfix) with ESMTP id 567D860C14; Thu, 21 Mar 2019 11:47:44 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 1/8] vfs: Add a single-or-reconfig keying to vfs_get_super() From: David Howells To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com Date: Thu, 21 Mar 2019 11:47:43 +0000 Message-ID: <155316886354.29437.8797952998692804823.stgit@warthog.procyon.org.uk> In-Reply-To: <155316885201.29437.3428987891437242750.stgit@warthog.procyon.org.uk> References: <155316885201.29437.3428987891437242750.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 21 Mar 2019 11:47:45 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add an additional keying mode to vfs_get_super() to indicate that only a single superblock should exist in the system, and that, if it does, further mounts should invoke reconfiguration upon it. This allows mount_single() to be replaced. Signed-off-by: David Howells --- fs/super.c | 18 +++++++++++++----- include/linux/fs_context.h | 1 + 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/fs/super.c b/fs/super.c index 6d8dbf309241..fa1d697b73bb 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1175,9 +1175,11 @@ int vfs_get_super(struct fs_context *fc, { int (*test)(struct super_block *, struct fs_context *); struct super_block *sb; + int err; switch (keying) { case vfs_get_single_super: + case vfs_get_single_reconf_super: test = test_single_super; break; case vfs_get_keyed_super: @@ -1195,18 +1197,24 @@ int vfs_get_super(struct fs_context *fc, return PTR_ERR(sb); if (!sb->s_root) { - int err = fill_super(sb, fc); - if (err) { - deactivate_locked_super(sb); - return err; - } + err = fill_super(sb, fc); + if (err) + goto error; sb->s_flags |= SB_ACTIVE; + } else if (keying == vfs_get_single_reconf_super) { + err = reconfigure_super(fc); + if (err < 0) + goto error; } BUG_ON(fc->root); fc->root = dget(sb->s_root); return 0; + +error: + deactivate_locked_super(sb); + return err; } EXPORT_SYMBOL(vfs_get_super); diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h index 8233c873af73..f1ed5ea0a041 100644 --- a/include/linux/fs_context.h +++ b/include/linux/fs_context.h @@ -136,6 +136,7 @@ extern int vfs_init_pseudo_fs_context(struct fs_context *fc, */ enum vfs_get_super_keying { vfs_get_single_super, /* Only one such superblock may exist */ + vfs_get_single_reconf_super, /* As above, but reconfigure if it exists */ vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */ vfs_get_independent_super, /* Multiple independent superblocks may exist */ };