From nobody Wed Nov 19 00:12:05 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1613563266124579.8496010317757; Wed, 17 Feb 2021 04:01:06 -0800 (PST) Received: from localhost ([::1]:50676 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lCLVI-0003CG-Gb for importer@patchew.org; Wed, 17 Feb 2021 07:00:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:48858) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lCLU0-0002Ll-GL for qemu-devel@nongnu.org; Wed, 17 Feb 2021 06:59:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:48011) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lCLTx-0002lk-Mi for qemu-devel@nongnu.org; Wed, 17 Feb 2021 06:59:03 -0500 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-415-ruAUQjTRMruOybgliv23kw-1; Wed, 17 Feb 2021 06:58:47 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C1FC1AFA80; Wed, 17 Feb 2021 11:58:46 +0000 (UTC) Received: from localhost (ovpn-114-112.ams2.redhat.com [10.36.114.112]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3534819D6C; Wed, 17 Feb 2021 11:58:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613563139; 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; bh=09plxGU+Bsvnk34ZEop/wZlOiub8bmqVmqpQ6t17O4Y=; b=UUwdioV24p3j/J8OIvtsdD6TE4zeCMITcxarSwOjlI3NFDdu1x2euhPWOweQE491aE7RFH dWs1vgRgIOue7v9JwOyjjvhJUsDOqrpbkW6VQDxECqcDcLzy1T3NZ5F42etwhevr7xy8X1 8Ls980FnBYxk9gI60aAxxWygN9SOs6k= X-MC-Unique: ruAUQjTRMruOybgliv23kw-1 From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH] qsd: Document FUSE exports Date: Wed, 17 Feb 2021 12:58:44 +0100 Message-Id: <20210217115844.62661-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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 , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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 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-d= aemon.rst index f63627eaf6..f5a906f6fc 100644 --- a/docs/tools/qemu-storage-daemon.rst +++ b/docs/tools/qemu-storage-daemon.rst @@ -74,6 +74,7 @@ Standard options: .. option:: --export [type=3D]nbd,id=3D,node-name=3D[,name= =3D][,writable=3Don|off][,bitmap=3D] --export [type=3D]vhost-user-blk,id=3D,node-name=3D,addr.= type=3Dunix,addr.path=3D[,writable=3Don|off][,logical-block-si= ze=3D][,num-queues=3D] --export [type=3D]vhost-user-blk,id=3D,node-name=3D,addr.= type=3Dfd,addr.str=3D[,writable=3Don|off][,logical-block-size=3D][,num-queues=3D] + --export [type=3D]fuse,id=3D,node-name=3D,mountpoint=3D[,growable=3Don|off][,writable=3Don|off] =20 is a block export definition. ``node-name`` is the block node that shoul= d be exported. ``writable`` determines whether or not the export allows write @@ -91,6 +92,16 @@ 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). =20 + The ``fuse`` export type takes a mount point, which must be a regular fi= le, + 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 ac= tive + (very much like mounting a filesystem on a directory does not change wha= t the + directory contains, it only shows a different content while the filesyst= em is + mounted). Consequently, applications that have opened the given file bef= ore + 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 =20 is a QMP monitor definition. See the :manpage:`qemu(1)` manual page for @@ -142,6 +153,14 @@ domain socket ``vhost-user-blk.sock``:: --blockdev driver=3Dqcow2,node-name=3Dqcow2,file=3Dfile \ --export type=3Dvhost-user-blk,id=3Dexport,addr.type=3Dunix,addr.pat= h=3Dvhost-user-blk.sock,node-name=3Dqcow2 =20 +Export a qcow2 image file ``disk.qcow2`` via FUSE on itself, so the disk i= mage +file will then appear as a raw image:: + + $ qemu-storage-daemon \ + --blockdev driver=3Dfile,node-name=3Dfile,filename=3Ddisk.qcow2 \ + --blockdev driver=3Dqcow2,node-name=3Dqcow2,file=3Dfile \ + --export type=3Dfuse,id=3Dexport,node-name=3Dqcow2,mountpoint=3Ddisk= .qcow2,writable=3Don + See also -------- =20 diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-sto= rage-daemon.c index 9021a46b3a..bdf8877995 100644 --- a/storage-daemon/qemu-storage-daemon.c +++ b/storage-daemon/qemu-storage-daemon.c @@ -97,6 +97,10 @@ static void help(void) " export the specified block node over NBD\n" " (requires --nbd-server)\n" "\n" +" --export [type=3D]fuse,id=3D,node-name=3D,mountpoint=3D<= file>\n" +" [,growable=3Don|off][,writable=3Don|off]\n" +" export the specified block node over FUSE\n" +"\n" " --monitor [chardev=3D]name[,mode=3Dcontrol][,pretty[=3Don|off]]\n" " configure a QMP monitor\n" "\n" --=20 2.29.2