From patchwork Fri Jun 4 16:11:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kurz X-Patchwork-Id: 12300059 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C4E14C47083 for ; Fri, 4 Jun 2021 16:12:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2920613FF for ; Fri, 4 Jun 2021 16:12:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231396AbhFDQOJ convert rfc822-to-8bit (ORCPT ); Fri, 4 Jun 2021 12:14:09 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:24286 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231289AbhFDQOI (ORCPT ); Fri, 4 Jun 2021 12:14:08 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-564-t0Dzju7TPcSRjZqzmv1G4Q-1; Fri, 04 Jun 2021 12:12:18 -0400 X-MC-Unique: t0Dzju7TPcSRjZqzmv1G4Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4E0011007B1A; Fri, 4 Jun 2021 16:12:17 +0000 (UTC) Received: from bahia.lan (ovpn-112-232.ams2.redhat.com [10.36.112.232]) by smtp.corp.redhat.com (Postfix) with ESMTP id B7DAF648A1; Fri, 4 Jun 2021 16:12:15 +0000 (UTC) From: Greg Kurz To: Miklos Szeredi Cc: linux-kernel@vger.kernel.org, Max Reitz , linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, Vivek Goyal , Greg Kurz Subject: [PATCH v2 4/7] fuse: Add dedicated filesystem context ops for submounts Date: Fri, 4 Jun 2021 18:11:53 +0200 Message-Id: <20210604161156.408496-5-groug@kaod.org> In-Reply-To: <20210604161156.408496-1-groug@kaod.org> References: <20210604161156.408496-1-groug@kaod.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=groug@kaod.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kaod.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The creation of a submount is open-coded in fuse_dentry_automount(). This brings a lot of complexity and we recently had to fix bugs because we weren't setting SB_BORN or because we were unlocking sb->s_umount before sb was fully configured. Most of these could have been avoided by using the mount API instead of open-coding. Basically, this means coming up with a proper ->get_tree() implementation for submounts and call vfs_get_tree(), or better fc_mount(). The creation of the superblock for submounts is quite different from the root mount. Especially, it doesn't require to allocate a FUSE filesystem context, nor to parse parameters. Introduce a dedicated context ops for submounts to make this clear. This is just a placeholder for now, fuse_get_tree_submount() will be populated in a subsequent patch. Only visible change is that we stop allocating/freeing a useless FUSE filesystem context with submounts. Signed-off-by: Greg Kurz Reviewed-by: Max Reitz --- fs/fuse/fuse_i.h | 5 +++++ fs/fuse/inode.c | 16 ++++++++++++++++ fs/fuse/virtio_fs.c | 3 +++ 3 files changed, 24 insertions(+) diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 7e463e220053..862ad317bc89 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -1097,6 +1097,11 @@ int fuse_fill_super_submount(struct super_block *sb, */ bool fuse_mount_remove(struct fuse_mount *fm); +/* + * Setup context ops for submounts + */ +int fuse_init_fs_context_submount(struct fs_context *fsc); + /* * Shut down the connection (possibly sending DESTROY request). */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 393e36b74dc4..fa96a3762ea2 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1313,6 +1313,22 @@ int fuse_fill_super_submount(struct super_block *sb, return 0; } +static int fuse_get_tree_submount(struct fs_context *fsc) +{ + return 0; +} + +static const struct fs_context_operations fuse_context_submount_ops = { + .get_tree = fuse_get_tree_submount, +}; + +int fuse_init_fs_context_submount(struct fs_context *fsc) +{ + fsc->ops = &fuse_context_submount_ops; + return 0; +} +EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); + int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) { struct fuse_dev *fud = NULL; diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index bcb8a02e2d8b..e68467cc765c 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -1496,6 +1496,9 @@ static int virtio_fs_init_fs_context(struct fs_context *fsc) { struct fuse_fs_context *ctx; + if (fsc->purpose == FS_CONTEXT_FOR_SUBMOUNT) + return fuse_init_fs_context_submount(fsc); + ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); if (!ctx) return -ENOMEM;