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 <xiaw...@linux.vnet.ibm.com>
---
block/snapshot.c | 18 +++++++++++++++++
include/block/snapshot.h | 8 +++++++
qemu-nbd.c | 47 ++++++++++++++++++++++++++++++++++++++++++++-
qemu-nbd.texi | 8 ++++++-
4 files changed, 78 insertions(+), 3 deletions(-)
diff --git a/block/snapshot.c b/block/snapshot.c
index e51a7db..7cc45fa 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..f934eaa 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>
@@ -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 +439,18 @@ int main(int argc, char **argv)
errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
}
break;
+ case 'l':
+ if (strncmp(optarg, SNAPSHOT_OPT_BASE, strlen(SNAPSHOT_OPT_BASE))
+ == 0) {