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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 BFDD2C43603 for ; Fri, 20 Dec 2019 13:03:34 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 7DC592067C for ; Fri, 20 Dec 2019 13:03:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LcBhrFk3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7DC592067C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55098 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iiHwL-00062Z-N0 for qemu-devel@archiver.kernel.org; Fri, 20 Dec 2019 08:03:33 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53972) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iiHvB-00054z-IG for qemu-devel@nongnu.org; Fri, 20 Dec 2019 08:02:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iiHv6-00087e-Ct for qemu-devel@nongnu.org; Fri, 20 Dec 2019 08:02:21 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:36407 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iiHv6-00086B-6B for qemu-devel@nongnu.org; Fri, 20 Dec 2019 08:02:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576846935; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NMX8TPumHETGIvt66tVBb2cmbuaQl0z4CMrEQI60adI=; b=LcBhrFk393Z/oB1gKxt56k974SfHE5Q/Zi9TxnhRJjbprNpUN9RJ9TncS2pONoFy8KVx4Y NSyaAIRlj1vIVDH3DFBIZdLzRYHOYOQvOuvLFLbaaOjEzg85vqSJ7uPYF1kLLq79e9KGhb uhQehABS7Mu6gkLkx3ltNb5GLGVMiRM= 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-403-MLRCa-CPPkuopXUf0Jvw9Q-1; Fri, 20 Dec 2019 08:02:12 -0500 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 818D9DBE6; Fri, 20 Dec 2019 13:02:11 +0000 (UTC) Received: from dhcp-200-226.str.redhat.com (dhcp-200-226.str.redhat.com [10.33.200.226]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 13D315C28F; Fri, 20 Dec 2019 13:02:08 +0000 (UTC) Date: Fri, 20 Dec 2019 14:02:07 +0100 From: Kevin Wolf To: Markus Armbruster Subject: Re: [PATCH 02/18] fuse: Allow exporting BDSs via FUSE Message-ID: <20191220130207.GH4019@dhcp-200-226.str.redhat.com> References: <20191219143818.1646168-1-mreitz@redhat.com> <20191219143818.1646168-3-mreitz@redhat.com> <20191220102656.GD4019@dhcp-200-226.str.redhat.com> <87lfr7go0z.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87lfr7go0z.fsf@dusky.pond.sub.org> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: MLRCa-CPPkuopXUf0Jvw9Q-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 20.12.2019 um 13:49 hat Markus Armbruster geschrieben: > Kevin Wolf writes: >=20 > > Am 19.12.2019 um 15:38 hat Max Reitz geschrieben: > >> fuse-export-add allows mounting block graph nodes via FUSE on some > >> existing regular file. That file should then appears like a raw disk > >> image, and accesses to it result in accesses to the exported BDS. > >>=20 > >> Right now, we only set up the mount point and tear all mount points do= wn > >> in bdrv_close_all(). We do not implement any access functions, so > >> accessing the mount point only results in errors. This will be > >> addressed by a followup patch. > >>=20 > >> The set of exported nodes is kept in a hash table so we can later add = a > >> fuse-export-remove that allows unmounting. > >>=20 > >> Signed-off-by: Max Reitz > > > >> diff --git a/qapi/block.json b/qapi/block.json > >> index 145c268bb6..03f8d1b537 100644 > >> --- a/qapi/block.json > >> +++ b/qapi/block.json > >> @@ -317,6 +317,29 @@ > >> ## > >> { 'command': 'nbd-server-stop' } > >> =20 > >> +## > >> +# @fuse-export-add: > >> +# > >> +# Exports a block graph node on some (file) mountpoint as a raw image= . > >> +# > >> +# @node-name: Node to be exported > >> +# > >> +# @mountpoint: Path on which to export the block device via FUSE. > >> +# This must point to an existing regular file. > >> +# > >> +# @writable: Whether clients should be able to write to the block > >> +# device via the FUSE export. (default: false) > >> +# > >> +# Since: 5.0 > >> +## > >> +{ 'command': 'fuse-export-add', > >> + 'data': { > >> + 'node-name': 'str', > >> + 'mountpoint': 'str', > >> + '*writable': 'bool' > >> + }, > >> + 'if': 'defined(CONFIG_FUSE)' } > > > > Can this use a BlockExport union from the start like I'm introducing in > > the storage daemon series, together with a generic block-export-add? > > > > It also looks like node-name and writable should be part of the common > > base of BlockExport. Unfortunately this would mean that I can't use the > > same BlockExportNbd for the existing nbd-server-add command any more. I > > guess I could somehow get a shared base type for both, though. > > > > Markus, any thoughts on these QAPI interfaces? >=20 > Context? How far back should I read? Basically just the hunk quoted above and the QAPI portion of the following storage daemon patch: [RFC PATCH 08/18] qemu-storage-daemon: Add --export option Maybe the cover letter, too, if you need a more high-level introduction. Kevin