From patchwork Tue Sep 1 20:40:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 11749457 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 E3C5613B1 for ; Tue, 1 Sep 2020 20:41:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC78D207D3 for ; Tue, 1 Sep 2020 20:41:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LxajRk1A" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbgIAUle (ORCPT ); Tue, 1 Sep 2020 16:41:34 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:56492 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726091AbgIAUle (ORCPT ); Tue, 1 Sep 2020 16:41:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598992893; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TbD6iyPHh1QOxOewfASpUhAaecUK7MkCtFkbWC3ePDU=; b=LxajRk1AUZBlKIDz8gfnkFAJuOH76tOkapLBo8T4pFCmMQqQ2iq8zKv1k5AHPXo1b4FJXq qYoOx729VpPwDTnS8qG0xHhS2IYrr3pkeSotIpSncrOArXOsIGabNWKNdBaMfl6EChSJev tWZxFAgey4cA8ib2DP1up+45viDDfD0= 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-238-G6clpIqMM1Gr6jwbsBQ91A-1; Tue, 01 Sep 2020 16:41:04 -0400 X-MC-Unique: G6clpIqMM1Gr6jwbsBQ91A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 89A00802B66; Tue, 1 Sep 2020 20:41:02 +0000 (UTC) Received: from horse.redhat.com (ovpn-116-208.rdu2.redhat.com [10.10.116.208]) by smtp.corp.redhat.com (Postfix) with ESMTP id B5E475C1C4; Tue, 1 Sep 2020 20:40:55 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 46F862255D9; Tue, 1 Sep 2020 16:40:55 -0400 (EDT) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, miklos@szeredi.hu Cc: vgoyal@redhat.com, stefanha@redhat.com, dgilbert@redhat.com Subject: [PATCH 2/2] fuse: Enable SB_NOSEC if filesystem is not shared Date: Tue, 1 Sep 2020 16:40:45 -0400 Message-Id: <20200901204045.1250822-3-vgoyal@redhat.com> In-Reply-To: <20200901204045.1250822-1-vgoyal@redhat.com> References: <20200901204045.1250822-1-vgoyal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org We don't enable SB_NOSEC on fuse filesystems thinking filesystem is shared and files attrs setuid/setgid/capabilities can change without fuse knowing about it. This means on every WRITE, file_remove_privs(), is called and that calls into fuse server to figure out if security.capability xattr has been set on file. Most of the time this is a performance hog, specially for small writes done at high frequency. Enable SB_NOSEC if fuse filesystem sets flag FS_NONSHARED_FS. This means, do not expect file attrs/xattrs to change without the knowledge of fuse. In this case it should be possible to enable SB_NOSEC. For the case of shared filesystems, we will have to come up with a different mechanism to enable SB_NOSEC. I guess it will depend on invalidation mechanisms implemented by filesystem and cache coherency guarantees. I do clear inode S_NOSEC flag whenever file attrs are being refreshed. So this still honors attr timeout protocol. Signed-off-by: Vivek Goyal --- fs/fuse/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 088faa3e352c..2da13fe25417 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -187,6 +187,9 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, inode->i_mode &= ~S_ISVTX; fi->orig_ino = attr->ino; + + /* Clear S_NOSEC whenever cached attrs are being refreshed */ + inode->i_flags &= ~S_NOSEC; } void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, @@ -967,6 +970,9 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args, } if (arg->flags & FUSE_NONSHARED_FS) { fc->nonshared_fs = 1; + down_write(&fc->sb->s_umount); + fc->sb->s_flags |= SB_NOSEC; + up_write(&fc->sb->s_umount); } } else { ra_pages = fc->max_read / PAGE_SIZE;