qmp: convert blockdev-snapshot-sync to a wrapper around transactions
Simplify the blockdev-snapshot-sync code and gain failsafe operation
by turning it into a wrapper around the new transaction command. A new
option is also added matching "mode".
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/blockdev.c b/blockdev.c
index 0a6edc3..1a500b8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -649,72 +649,33 @@
}
}
+static void blockdev_do_action(int kind, void *data, Error **errp)
+{
+ BlockdevAction action;
+ BlockdevActionList list;
+
+ action.kind = kind;
+ action.data = data;
+ list.value = &action;
+ list.next = NULL;
+ qmp_transaction(&list, errp);
+}
+
void qmp_blockdev_snapshot_sync(const char *device, const char *snapshot_file,
bool has_format, const char *format,
+ bool has_mode, enum NewImageMode mode,
Error **errp)
{
- BlockDriverState *bs;
- BlockDriver *drv, *old_drv, *proto_drv;
- int ret = 0;
- int flags;
- char old_filename[1024];
-
- bs = bdrv_find(device);
- if (!bs) {
- error_set(errp, QERR_DEVICE_NOT_FOUND, device);
- return;
- }
- if (bdrv_in_use(bs)) {
- error_set(errp, QERR_DEVICE_IN_USE, device);
- return;
- }
-
- pstrcpy(old_filename, sizeof(old_filename), bs->filename);
-
- old_drv = bs->drv;
- flags = bs->open_flags;
-
- if (!has_format) {
- format = "qcow2";
- }
-
- drv = bdrv_find_format(format);
- if (!drv) {
- error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
- return;
- }
-
- proto_drv = bdrv_find_protocol(snapshot_file);
- if (!proto_drv) {
- error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
- return;
- }
-
- ret = bdrv_img_create(snapshot_file, format, bs->filename,
- bs->drv->format_name, NULL, -1, flags);
- if (ret) {
- error_set(errp, QERR_UNDEFINED_ERROR);
- return;
- }
-
- bdrv_drain_all();
- bdrv_flush(bs);
-
- bdrv_close(bs);
- ret = bdrv_open(bs, snapshot_file, flags, drv);
- /*
- * If reopening the image file we just created fails, fall back
- * and try to re-open the original image. If that fails too, we
- * are in serious trouble.
- */
- if (ret != 0) {
- ret = bdrv_open(bs, old_filename, flags, old_drv);
- if (ret != 0) {
- error_set(errp, QERR_OPEN_FILE_FAILED, old_filename);
- } else {
- error_set(errp, QERR_OPEN_FILE_FAILED, snapshot_file);
- }
- }
+ BlockdevSnapshot snapshot = {
+ .device = (char *) device,
+ .snapshot_file = (char *) snapshot_file,
+ .has_format = has_format,
+ .format = (char *) format,
+ .has_mode = has_mode,
+ .mode = mode,
+ };
+ blockdev_do_action(BLOCKDEV_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC, &snapshot,
+ errp);
}
diff --git a/hmp-commands.hx b/hmp-commands.hx
index ed88877..6980214 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -882,14 +882,17 @@
{
.name = "snapshot_blkdev",
- .args_type = "device:B,snapshot-file:s?,format:s?",
- .params = "device [new-image-file] [format]",
+ .args_type = "reuse:-n,device:B,snapshot-file:s?,format:s?",
+ .params = "[-n] device [new-image-file] [format]",
.help = "initiates a live snapshot\n\t\t\t"
"of device. If a new image file is specified, the\n\t\t\t"
"new image file will become the new root image.\n\t\t\t"
"If format is specified, the snapshot file will\n\t\t\t"
"be created in that format. Otherwise the\n\t\t\t"
- "snapshot will be internal! (currently unsupported)",
+ "snapshot will be internal! (currently unsupported).\n\t\t\t"
+ "The default format is qcow2. The -n flag requests QEMU\n\t\t\t"
+ "to reuse the image found in new-image-file, instead of\n\t\t\t"
+ "recreating it from scratch.",
.mhandler.cmd = hmp_snapshot_blkdev,
},
diff --git a/hmp.c b/hmp.c
index 3a54455..290c43d 100644
--- a/hmp.c
+++ b/hmp.c
@@ -692,6 +692,8 @@
const char *device = qdict_get_str(qdict, "device");
const char *filename = qdict_get_try_str(qdict, "snapshot-file");
const char *format = qdict_get_try_str(qdict, "format");
+ int reuse = qdict_get_try_bool(qdict, "reuse", 0);
+ enum NewImageMode mode;
Error *errp = NULL;
if (!filename) {
@@ -702,7 +704,9 @@
return;
}
- qmp_blockdev_snapshot_sync(device, filename, !!format, format, &errp);
+ mode = reuse ? NEW_IMAGE_MODE_EXISTING : NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+ qmp_blockdev_snapshot_sync(device, filename, !!format, format,
+ true, mode, &errp);
hmp_handle_error(mon, &errp);
}
diff --git a/qapi-schema.json b/qapi-schema.json
index 0882f43..4df6b8f 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1141,6 +1141,9 @@
# @snapshot-file: the target of the new image. A new file will be created.
#
# @format: #optional the format of the snapshot image, default is 'qcow2'.
+#
+# @mode: #optional whether and how QEMU should create a new image, default is
+# 'absolute-paths'.
##
{ 'type': 'BlockdevSnapshot',
'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str',
@@ -1197,21 +1200,19 @@
#
# @format: #optional the format of the snapshot image, default is 'qcow2'.
#
+# @mode: #optional whether and how QEMU should create a new image, default is
+# 'absolute-paths'.
+#
# Returns: nothing on success
# If @device is not a valid block device, DeviceNotFound
# If @snapshot-file can't be opened, OpenFileFailed
# If @format is invalid, InvalidBlockFormat
#
-# Notes: One of the last steps taken by this command is to close the current
-# image being used by @device and open the @snapshot-file one. If that
-# fails, the command will try to reopen the original image file. If
-# that also fails OpenFileFailed will be returned and the guest may get
-# unexpected errors.
-#
# Since 0.14.0
##
{ 'command': 'blockdev-snapshot-sync',
- 'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str' } }
+ 'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str',
+ '*mode': 'NewImageMode'} }
##
# @human-monitor-command:
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 7c03b62..dfe8a5b 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -760,6 +760,8 @@
- "device": device name to snapshot (json-string)
- "snapshot-file": name of new image file (json-string)
+- "mode": whether and how QEMU should create the snapshot file
+ (NewImageMode, optional, default "absolute-paths")
- "format": format of new image (json-string, optional)
Example:
