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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D4762C433F5 for ; Mon, 7 Feb 2022 13:47:39 +0000 (UTC) Received: from localhost ([::1]:38338 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nH4Mi-0000iW-Po for qemu-devel@archiver.kernel.org; Mon, 07 Feb 2022 08:47:38 -0500 Received: from eggs.gnu.org ([209.51.188.92]:43568) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nH47G-0005UE-96 for qemu-devel@nongnu.org; Mon, 07 Feb 2022 08:31:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:44086) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nH47D-0003sP-G2 for qemu-devel@nongnu.org; Mon, 07 Feb 2022 08:31:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644240687; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=As1wxRfAjMh9G93UTiArjRqaais3VhrBpJBPQk2DEm4=; b=hCA5d7uky+BEFnUoyaeihf9sLkD59Pf6F4cDyHM6mBY1R3pch06yjejLs0EuNcne3UluA3 +085yRFKs3hpmWV+Zt2S3k1tYxmfkt743Wn/WG/cd9/4890vj9jpfkBXyCYzqWNi8A4Z0l fCYpXv4uQ/E8Shil8K/oyI1NVOXhoXQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-13-1sLBU8jeMJ68EzOtL0fsNg-1; Mon, 07 Feb 2022 08:31:26 -0500 X-MC-Unique: 1sLBU8jeMJ68EzOtL0fsNg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4D7FE814245 for ; Mon, 7 Feb 2022 13:31:25 +0000 (UTC) Received: from horse.redhat.com (unknown [10.22.9.190]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0087E1038AD4; Mon, 7 Feb 2022 13:31:24 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 834ED2237EB; Mon, 7 Feb 2022 08:31:24 -0500 (EST) Date: Mon, 7 Feb 2022 08:31:24 -0500 From: Vivek Goyal To: "Dr. David Alan Gilbert" Subject: Re: [PATCH v5 3/9] virtiofsd: Parse extended "struct fuse_init_in" Message-ID: References: <20220202193935.268777-1-vgoyal@redhat.com> <20220202193935.268777-4-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vgoyal@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=vgoyal@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, mszeredi@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Feb 03, 2022 at 06:56:58PM +0000, Dr. David Alan Gilbert wrote: > * Vivek Goyal (vgoyal@redhat.com) wrote: > > Add some code to parse extended "struct fuse_init_in". And use a local > > variable "flag" to represent 64 bit flags. This will make it easier > > to add more features without having to worry about two 32bit flags (->flags > > and ->flags2) in "fuse_struct_in". > > > > Signed-off-by: Vivek Goyal > > --- > > tools/virtiofsd/fuse_lowlevel.c | 62 +++++++++++++++++++++------------ > > 1 file changed, 40 insertions(+), 22 deletions(-) > > > > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c > > index ce29a70253..1f10dcc75b 100644 > > --- a/tools/virtiofsd/fuse_lowlevel.c > > +++ b/tools/virtiofsd/fuse_lowlevel.c > > @@ -1881,11 +1881,15 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, > > { > > size_t compat_size = offsetof(struct fuse_init_in, max_readahead); > > size_t compat2_size = offsetof(struct fuse_init_in, flags) + sizeof(uint32_t); > > + /* Fuse structure extended with minor version 36 */ > > + size_t compat3_size = offsetof(struct fuse_init_in, unused) + > > + (11 * sizeof(uint32_t)); > > Hmm that's actually quite difficult; what we have at the moment is: > > struct fuse_init_in { > uint32_t major; > uint32_t minor; > uint32_t max_readahead; > uint32_t flags; > uint32_t flags2; > uint32_t unused[11]; > }; > > so imagine someone comes along and changes that to: > > struct fuse_init_in { > uint32_t major; > uint32_t minor; > uint32_t max_readahead; > uint32_t flags; > uint32_t flags2; > uint32_t flags3; > uint32_t unused[10]; > }; > > Then this code will break (oddly!), where the old code that didn't reference the > unusued field wouldn't. Good catch. I did not think about it. > It looks like qemu defines an 'endof' macro, so I think you can do: > > size_t compat3_size = endof(struct fuse_init_in, unused); > > I think that should work as long as people nibble away at unused from > the top. Will use "endof" macro. Thanks Vivek > > Dave > > > > struct fuse_init_in *arg; > > struct fuse_init_out outarg; > > struct fuse_session *se = req->se; > > size_t bufsize = se->bufsize; > > size_t outargsize = sizeof(outarg); > > + uint64_t flags = 0; > > > > (void)nodeid; > > > > @@ -1902,11 +1906,25 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, > > fuse_reply_err(req, EINVAL); > > return; > > } > > + flags |= arg->flags; > > + } > > + > > + /* > > + * fuse_init_in was extended again with minor version 36. Just read > > + * current known size of fuse_init so that future extension and > > + * header rebase does not cause breakage. > > + */ > > + if (sizeof(*arg) > compat2_size && (arg->flags & FUSE_INIT_EXT)) { > > + if (!fuse_mbuf_iter_advance(iter, compat3_size - compat2_size)) { > > + fuse_reply_err(req, EINVAL); > > + return; > > + } > > + flags |= (uint64_t) arg->flags2 << 32; > > } > > > > fuse_log(FUSE_LOG_DEBUG, "INIT: %u.%u\n", arg->major, arg->minor); > > if (arg->major == 7 && arg->minor >= 6) { > > - fuse_log(FUSE_LOG_DEBUG, "flags=0x%08x\n", arg->flags); > > + fuse_log(FUSE_LOG_DEBUG, "flags=0x%016llx\n", flags); > > fuse_log(FUSE_LOG_DEBUG, "max_readahead=0x%08x\n", arg->max_readahead); > > } > > se->conn.proto_major = arg->major; > > @@ -1934,68 +1952,68 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, > > if (arg->max_readahead < se->conn.max_readahead) { > > se->conn.max_readahead = arg->max_readahead; > > } > > - if (arg->flags & FUSE_ASYNC_READ) { > > + if (flags & FUSE_ASYNC_READ) { > > se->conn.capable |= FUSE_CAP_ASYNC_READ; > > } > > - if (arg->flags & FUSE_POSIX_LOCKS) { > > + if (flags & FUSE_POSIX_LOCKS) { > > se->conn.capable |= FUSE_CAP_POSIX_LOCKS; > > } > > - if (arg->flags & FUSE_ATOMIC_O_TRUNC) { > > + if (flags & FUSE_ATOMIC_O_TRUNC) { > > se->conn.capable |= FUSE_CAP_ATOMIC_O_TRUNC; > > } > > - if (arg->flags & FUSE_EXPORT_SUPPORT) { > > + if (flags & FUSE_EXPORT_SUPPORT) { > > se->conn.capable |= FUSE_CAP_EXPORT_SUPPORT; > > } > > - if (arg->flags & FUSE_DONT_MASK) { > > + if (flags & FUSE_DONT_MASK) { > > se->conn.capable |= FUSE_CAP_DONT_MASK; > > } > > - if (arg->flags & FUSE_FLOCK_LOCKS) { > > + if (flags & FUSE_FLOCK_LOCKS) { > > se->conn.capable |= FUSE_CAP_FLOCK_LOCKS; > > } > > - if (arg->flags & FUSE_AUTO_INVAL_DATA) { > > + if (flags & FUSE_AUTO_INVAL_DATA) { > > se->conn.capable |= FUSE_CAP_AUTO_INVAL_DATA; > > } > > - if (arg->flags & FUSE_DO_READDIRPLUS) { > > + if (flags & FUSE_DO_READDIRPLUS) { > > se->conn.capable |= FUSE_CAP_READDIRPLUS; > > } > > - if (arg->flags & FUSE_READDIRPLUS_AUTO) { > > + if (flags & FUSE_READDIRPLUS_AUTO) { > > se->conn.capable |= FUSE_CAP_READDIRPLUS_AUTO; > > } > > - if (arg->flags & FUSE_ASYNC_DIO) { > > + if (flags & FUSE_ASYNC_DIO) { > > se->conn.capable |= FUSE_CAP_ASYNC_DIO; > > } > > - if (arg->flags & FUSE_WRITEBACK_CACHE) { > > + if (flags & FUSE_WRITEBACK_CACHE) { > > se->conn.capable |= FUSE_CAP_WRITEBACK_CACHE; > > } > > - if (arg->flags & FUSE_NO_OPEN_SUPPORT) { > > + if (flags & FUSE_NO_OPEN_SUPPORT) { > > se->conn.capable |= FUSE_CAP_NO_OPEN_SUPPORT; > > } > > - if (arg->flags & FUSE_PARALLEL_DIROPS) { > > + if (flags & FUSE_PARALLEL_DIROPS) { > > se->conn.capable |= FUSE_CAP_PARALLEL_DIROPS; > > } > > - if (arg->flags & FUSE_POSIX_ACL) { > > + if (flags & FUSE_POSIX_ACL) { > > se->conn.capable |= FUSE_CAP_POSIX_ACL; > > } > > - if (arg->flags & FUSE_HANDLE_KILLPRIV) { > > + if (flags & FUSE_HANDLE_KILLPRIV) { > > se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV; > > } > > - if (arg->flags & FUSE_NO_OPENDIR_SUPPORT) { > > + if (flags & FUSE_NO_OPENDIR_SUPPORT) { > > se->conn.capable |= FUSE_CAP_NO_OPENDIR_SUPPORT; > > } > > - if (!(arg->flags & FUSE_MAX_PAGES)) { > > + if (!(flags & FUSE_MAX_PAGES)) { > > size_t max_bufsize = FUSE_DEFAULT_MAX_PAGES_PER_REQ * getpagesize() + > > FUSE_BUFFER_HEADER_SIZE; > > if (bufsize > max_bufsize) { > > bufsize = max_bufsize; > > } > > } > > - if (arg->flags & FUSE_SUBMOUNTS) { > > + if (flags & FUSE_SUBMOUNTS) { > > se->conn.capable |= FUSE_CAP_SUBMOUNTS; > > } > > - if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) { > > + if (flags & FUSE_HANDLE_KILLPRIV_V2) { > > se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV_V2; > > } > > - if (arg->flags & FUSE_SETXATTR_EXT) { > > + if (flags & FUSE_SETXATTR_EXT) { > > se->conn.capable |= FUSE_CAP_SETXATTR_EXT; > > } > > #ifdef HAVE_SPLICE > > @@ -2063,7 +2081,7 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, > > if (se->conn.max_write < bufsize - FUSE_BUFFER_HEADER_SIZE) { > > se->bufsize = se->conn.max_write + FUSE_BUFFER_HEADER_SIZE; > > } > > - if (arg->flags & FUSE_MAX_PAGES) { > > + if (flags & FUSE_MAX_PAGES) { > > outarg.flags |= FUSE_MAX_PAGES; > > outarg.max_pages = (se->conn.max_write - 1) / getpagesize() + 1; > > } > > -- > > 2.34.1 > > > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >