From patchwork Wed Dec 4 09:10:55 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wayne Xia X-Patchwork-Id: 296453 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 04ADE2C00B6 for ; Wed, 4 Dec 2013 20:10:18 +1100 (EST) Received: from localhost ([::1]:47093 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vo8TH-000867-EH for incoming@patchwork.ozlabs.org; Wed, 04 Dec 2013 04:10:15 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36327) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vo8Sc-00084s-Vp for qemu-devel@nongnu.org; Wed, 04 Dec 2013 04:09:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vo8SU-0001sc-6z for qemu-devel@nongnu.org; Wed, 04 Dec 2013 04:09:34 -0500 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:43748) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vo8ST-0001sC-Ex for qemu-devel@nongnu.org; Wed, 04 Dec 2013 04:09:26 -0500 Received: from /spool/local by e28smtp06.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 4 Dec 2013 14:39:20 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 0DC071258054 for ; Wed, 4 Dec 2013 14:40:24 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rB499Fsq49741868 for ; Wed, 4 Dec 2013 14:39:15 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rB499JBb017195 for ; Wed, 4 Dec 2013 14:39:19 +0530 Received: from RH64wenchao ([9.181.129.59]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id rB499Eul016935; Wed, 4 Dec 2013 14:39:18 +0530 From: Wenchao Xia To: qemu-devel@nongnu.org Date: Wed, 4 Dec 2013 17:10:55 +0800 Message-Id: <1386148259-10962-3-git-send-email-xiawenc@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1386148259-10962-1-git-send-email-xiawenc@linux.vnet.ibm.com> References: <1386148259-10962-1-git-send-email-xiawenc@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13120409-9574-0000-0000-00000AE04D8D X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 122.248.162.6 Cc: kwolf@redhat.com, jcody@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, Wenchao Xia Subject: [Qemu-devel] [PATCH V7 2/6] qemu-nbd: support internal snapshot export X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Now it is possible to directly export an internal snapshot, which can be used to probe the snapshot's contents without qemu-img convert. Signed-off-by: Wenchao Xia --- block/snapshot.c | 18 ++++++++++++++++++ include/block/snapshot.h | 8 ++++++++ qemu-nbd.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-- qemu-nbd.texi | 8 +++++++- 4 files changed, 77 insertions(+), 3 deletions(-) diff --git a/block/snapshot.c b/block/snapshot.c index 565222e..9047f8d 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -25,6 +25,24 @@ #include "block/snapshot.h" #include "block/block_int.h" +QemuOptsList internal_snapshot_opts = { + .name = "snapshot", + .head = QTAILQ_HEAD_INITIALIZER(internal_snapshot_opts.head), + .desc = { + { + .name = SNAPSHOT_OPT_ID, + .type = QEMU_OPT_STRING, + .help = "snapshot id" + },{ + .name = SNAPSHOT_OPT_NAME, + .type = QEMU_OPT_STRING, + .help = "snapshot name" + },{ + /* end of list */ + } + }, +}; + int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info, const char *name) { diff --git a/include/block/snapshot.h b/include/block/snapshot.h index d05bea7..770d9bb 100644 --- a/include/block/snapshot.h +++ b/include/block/snapshot.h @@ -27,6 +27,14 @@ #include "qemu-common.h" #include "qapi/error.h" +#include "qemu/option.h" + + +#define SNAPSHOT_OPT_BASE "snapshot." +#define SNAPSHOT_OPT_ID "snapshot.id" +#define SNAPSHOT_OPT_NAME "snapshot.name" + +extern QemuOptsList internal_snapshot_opts; typedef struct QEMUSnapshotInfo { char id_str[128]; /* unique snapshot id */ diff --git a/qemu-nbd.c b/qemu-nbd.c index c26c98e..fe6053c 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -20,6 +20,7 @@ #include "block/block.h" #include "block/nbd.h" #include "qemu/main-loop.h" +#include "block/snapshot.h" #include #include @@ -79,7 +80,14 @@ static void usage(const char *name) "\n" "Block device options:\n" " -r, --read-only export read-only\n" -" -s, --snapshot use snapshot file\n" +" -s, --snapshot use FILE as an external snapshot, create a temporary\n" +" file with backing_file=FILE, redirect the write to\n" +" the temporary one\n" +" -l, --load-snapshot=SNAPSHOT_PARAM\n" +" load an internal snapshot inside FILE and export it\n" +" as an read-only device, SNAPSHOT_PARAM format is\n" +" 'snapshot.id=[ID],snapshot.name=[NAME]', or\n" +" '[ID_OR_NAME]'\n" " -n, --nocache disable host cache\n" " --cache=MODE set cache mode (none, writeback, ...)\n" #ifdef CONFIG_LINUX_AIO @@ -315,7 +323,9 @@ int main(int argc, char **argv) char *device = NULL; int port = NBD_DEFAULT_PORT; off_t fd_size; - const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:t"; + QemuOpts *sn_opts = NULL; + const char *sn_id_or_name = NULL; + const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:"; struct option lopt[] = { { "help", 0, NULL, 'h' }, { "version", 0, NULL, 'V' }, @@ -328,6 +338,7 @@ int main(int argc, char **argv) { "connect", 1, NULL, 'c' }, { "disconnect", 0, NULL, 'd' }, { "snapshot", 0, NULL, 's' }, + { "load-snapshot", 1, NULL, 'l' }, { "nocache", 0, NULL, 'n' }, { "cache", 1, NULL, QEMU_NBD_OPT_CACHE }, #ifdef CONFIG_LINUX_AIO @@ -428,6 +439,17 @@ int main(int argc, char **argv) errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg); } break; + case 'l': + if (strstart(optarg, SNAPSHOT_OPT_BASE, NULL)) { + sn_opts = qemu_opts_parse(&internal_snapshot_opts, optarg, 0); + if (!sn_opts) { + errx(EXIT_FAILURE, "Failed in parsing snapshot param `%s'", + optarg); + } + } else { + sn_id_or_name = optarg; + } + /* fall through */ case 'r': nbdflags |= NBD_FLAG_READ_ONLY; flags &= ~BDRV_O_RDWR; @@ -581,6 +603,22 @@ int main(int argc, char **argv) error_get_pretty(local_err)); } + if (sn_opts) { + ret = bdrv_snapshot_load_tmp(bs, + qemu_opt_get(sn_opts, SNAPSHOT_OPT_ID), + qemu_opt_get(sn_opts, SNAPSHOT_OPT_NAME), + &local_err); + } else if (sn_id_or_name) { + ret = bdrv_snapshot_load_tmp_by_id_or_name(bs, sn_id_or_name, + &local_err); + } + if (ret < 0) { + errno = -ret; + err(EXIT_FAILURE, + "Failed to load snapshot: %s", + error_get_pretty(local_err)); + } + fd_size = bdrv_getlength(bs); if (partition != -1) { @@ -641,6 +679,10 @@ int main(int argc, char **argv) unlink(sockpath); } + if (sn_opts) { + qemu_opts_del(sn_opts); + } + if (device) { void *ret; pthread_join(client_thread, &ret); diff --git a/qemu-nbd.texi b/qemu-nbd.texi index 6055ec6..5b55f76 100644 --- a/qemu-nbd.texi +++ b/qemu-nbd.texi @@ -27,7 +27,13 @@ Export QEMU disk image using NBD protocol. @item -P, --partition=@var{num} only expose partition @var{num} @item -s, --snapshot - use snapshot file + use @var{filename} as an external snapshot, create a temporary + file with backing_file=@var{filename}, redirect the write to + the temporary one +@item -l, --load-snapshot=@var{snapshot_param} + load an internal snapshot inside @var{filename} and export it + as an read-only device, @var{snapshot_param} format is + 'snapshot.id=[ID],snapshot.name=[NAME]' or '[ID_OR_NAME]' @item -n, --nocache @itemx --cache=@var{cache} set cache mode to be used with the file. See the documentation of