From patchwork Tue Mar 30 12:39:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 12172467 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 11179C433C1 for ; Tue, 30 Mar 2021 12:49:21 +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 91A3E61957 for ; Tue, 30 Mar 2021 12:49:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91A3E61957 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]:59220 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRDo7-0007dJ-LJ for qemu-devel@archiver.kernel.org; Tue, 30 Mar 2021 08:49:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58348) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRDfd-000147-14 for qemu-devel@nongnu.org; Tue, 30 Mar 2021 08:40:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:41019) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRDfS-0003QL-4F for qemu-devel@nongnu.org; Tue, 30 Mar 2021 08:40:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617108019; 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=BcV7OFirmTsF/6Vx4L9qORemtTd4108boUdPewlJ840=; b=YY55cID8R2/up8Fk/5VTWClUcMUF7DMjd/Dy25JccsAd1uPvF1Csx96W4ldG/um5NoGvg6 6+wsx9fXhmyckb40hLqfyWyko7LK3eucxzy0tyivPzy3mY5qSF87Tz/Os6lRLlzvZ96/az QDUqw/cpgc+kXLt5GkzHet1PETpKQqQ= 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-346-HEDJC3NRNueQFDhhwveYdg-1; Tue, 30 Mar 2021 08:40:15 -0400 X-MC-Unique: HEDJC3NRNueQFDhhwveYdg-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id D5499DF8A9; Tue, 30 Mar 2021 12:40:14 +0000 (UTC) Received: from localhost (ovpn-113-220.ams2.redhat.com [10.36.113.220]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 799E12AC85; Tue, 30 Mar 2021 12:40:14 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 7/9] qsd: Document FUSE exports Date: Tue, 30 Mar 2021 14:39:55 +0200 Message-Id: <20210330123957.826170-8-mreitz@redhat.com> In-Reply-To: <20210330123957.826170-1-mreitz@redhat.com> References: <20210330123957.826170-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=mreitz@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, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Implementing FUSE exports required no changes to the storage daemon, so we forgot to document them there. Considering that both NBD and vhost-user-blk exports are documented in its man page (and NBD exports in its --help text), we should probably do the same for FUSE. Signed-off-by: Max Reitz Message-Id: <20210217115844.62661-1-mreitz@redhat.com> Reviewed-by: Eric Blake --- docs/tools/qemu-storage-daemon.rst | 19 +++++++++++++++++++ storage-daemon/qemu-storage-daemon.c | 4 ++++ 2 files changed, 23 insertions(+) diff --git a/docs/tools/qemu-storage-daemon.rst b/docs/tools/qemu-storage-daemon.rst index 086493ebb3..3ec4bdd914 100644 --- a/docs/tools/qemu-storage-daemon.rst +++ b/docs/tools/qemu-storage-daemon.rst @@ -74,6 +74,7 @@ Standard options: .. option:: --export [type=]nbd,id=,node-name=[,name=][,writable=on|off][,bitmap=] --export [type=]vhost-user-blk,id=,node-name=,addr.type=unix,addr.path=[,writable=on|off][,logical-block-size=][,num-queues=] --export [type=]vhost-user-blk,id=,node-name=,addr.type=fd,addr.str=[,writable=on|off][,logical-block-size=][,num-queues=] + --export [type=]fuse,id=,node-name=,mountpoint=[,growable=on|off][,writable=on|off] is a block export definition. ``node-name`` is the block node that should be exported. ``writable`` determines whether or not the export allows write @@ -92,6 +93,16 @@ Standard options: ``logical-block-size`` sets the logical block size in bytes (the default is 512). ``num-queues`` sets the number of virtqueues (the default is 1). + The ``fuse`` export type takes a mount point, which must be a regular file, + on which to export the given block node. That file will not be changed, it + will just appear to have the block node's content while the export is active + (very much like mounting a filesystem on a directory does not change what the + directory contains, it only shows a different content while the filesystem is + mounted). Consequently, applications that have opened the given file before + the export became active will continue to see its original content. If + ``growable`` is set, writes after the end of the exported file will grow the + block node to fit. + .. option:: --monitor MONITORDEF is a QMP monitor definition. See the :manpage:`qemu(1)` manual page for @@ -196,6 +207,14 @@ domain socket ``vhost-user-blk.sock``:: --blockdev driver=qcow2,node-name=qcow2,file=file \ --export type=vhost-user-blk,id=export,addr.type=unix,addr.path=vhost-user-blk.sock,node-name=qcow2 +Export a qcow2 image file ``disk.qcow2`` via FUSE on itself, so the disk image +file will then appear as a raw image:: + + $ qemu-storage-daemon \ + --blockdev driver=file,node-name=file,filename=disk.qcow2 \ + --blockdev driver=qcow2,node-name=qcow2,file=file \ + --export type=fuse,id=export,node-name=qcow2,mountpoint=disk.qcow2,writable=on + See also -------- diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-storage-daemon.c index 72900dc2ec..fc8b150629 100644 --- a/storage-daemon/qemu-storage-daemon.c +++ b/storage-daemon/qemu-storage-daemon.c @@ -98,6 +98,10 @@ static void help(void) " export the specified block node over NBD\n" " (requires --nbd-server)\n" "\n" +" --export [type=]fuse,id=,node-name=,mountpoint=\n" +" [,growable=on|off][,writable=on|off]\n" +" export the specified block node over FUSE\n" +"\n" " --monitor [chardev=]name[,mode=control][,pretty[=on|off]]\n" " configure a QMP monitor\n" "\n"