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Re: [Qemu-devel] [PATCH V2 2/4] qemu-nbd: support internal snapshot expo
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH V2 2/4] qemu-nbd: support internal snapshot export |
Date: |
Mon, 23 Sep 2013 12:25:57 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 |
Il 22/09/2013 11:39, Wenchao Xia ha scritto:
> 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 <address@hidden>
> ---
> qemu-nbd.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 53 insertions(+), 1 deletions(-)
>
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index c26c98e..e450d04 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 <stdarg.h>
> #include <stdio.h>
> @@ -304,6 +305,23 @@ static void nbd_accept(void *opaque)
> }
> }
>
> +#define SNAPSHOT_OPT_ID "id"
> +#define SNAPSHOT_OPT_NAME "name"
> +
> +static QEMUOptionParameter snapshot_options[] = {
> + {
> + .name = SNAPSHOT_OPT_ID,
> + .type = OPT_STRING,
> + .help = "snapshot id"
> + },
> + {
> + .name = SNAPSHOT_OPT_NAME,
> + .type = OPT_STRING,
> + .help = "snapshot name"
> + },
> + { NULL }
> +};
I think whatever mechanism you use here to pick a snapshot id or name
should be implemented in qemu-img too.
Also, I think QEMUOptionParameter is being phased out.
> int main(int argc, char **argv)
> {
> BlockDriverState *bs;
> @@ -315,7 +333,10 @@ 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";
> + QEMUOptionParameter *sn_param = NULL;
> + const QEMUOptionParameter *sn_param_id, *sn_param_name;
> + const char *sn_id = NULL, *sn_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 +349,7 @@ int main(int argc, char **argv)
> { "connect", 1, NULL, 'c' },
> { "disconnect", 0, NULL, 'd' },
> { "snapshot", 0, NULL, 's' },
> + { "snapshot-load", 1, NULL, 'l' },
Please call this option "load-snapshot".
Paolo
> { "nocache", 0, NULL, 'n' },
> { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
> #ifdef CONFIG_LINUX_AIO
> @@ -428,6 +450,14 @@ int main(int argc, char **argv)
> errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
> }
> break;
> + case 'l':
> + sn_param = parse_option_parameters(optarg,
> + snapshot_options, sn_param);
> + if (!sn_param) {
> + errx(EXIT_FAILURE,
> + "Invalid snapshot-load options '%s'", optarg);
> + }
> + /* fall through */
> case 'r':
> nbdflags |= NBD_FLAG_READ_ONLY;
> flags &= ~BDRV_O_RDWR;
> @@ -581,6 +611,24 @@ int main(int argc, char **argv)
> error_get_pretty(local_err));
> }
>
> + if (sn_param) {
> + sn_param_id = get_option_parameter(sn_param, SNAPSHOT_OPT_ID);
> + sn_param_name = get_option_parameter(sn_param, SNAPSHOT_OPT_NAME);
> + if (sn_param_id) {
> + sn_id = sn_param_id->value.s;
> + }
> + if (sn_param_name) {
> + sn_name = sn_param_name->value.s;
> + }
> + ret = bdrv_snapshot_load_tmp(bs, sn_id, sn_name, &local_err);
> + if (ret < 0) {
> + errno = -ret;
> + err(EXIT_FAILURE,
> + "Failed to load snapshot, reason:\n%s",
> + error_get_pretty(local_err));
> + }
> + }
> +
> fd_size = bdrv_getlength(bs);
>
> if (partition != -1) {
> @@ -641,6 +689,10 @@ int main(int argc, char **argv)
> unlink(sockpath);
> }
>
> + if (sn_param) {
> + free_option_parameters(sn_param);
> + }
> +
> if (device) {
> void *ret;
> pthread_join(client_thread, &ret);
>