This patch adds a transactional version of the drive-backup QMP command.
It allows atomic snapshots of multiple drives along with automatic
cleanup if there is a failure to start one of the backup jobs.
Note that QMP events are emitted for block job completion/cancellation
and the block job will be listed by query-block-jobs.
@DriveBackup
@device: the name of the device whose writes should be mirrored.
@target: the target of the new image. If the file exists, or if it
is a device, the existing file/device will be used as the new
destination. If it does not exist, a new file will be created.
@format: #optional the format of the new destination, default is to
probe if @mode is 'existing', else the format of the source
@mode: #optional whether and how QEMU should create a new image, default is
'absolute-paths'.
@speed: #optional the maximum speed, in bytes per second
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
blockdev.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
qapi-schema.json | 26 +++++++++++++++++++++++++-
2 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index b6109da..c386bb6 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -926,6 +926,53 @@ static void external_snapshot_abort(BlkTransactionState
*common)
}
}
+typedef struct DriveBackupState {
+ BlkTransactionState common;
+ BlockDriverState *bs;
+ BlockJob *job;
+} DriveBackupState;
+
+static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
+{
+ DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+ DriveBackup *backup;
+ Error *local_err = NULL;
+
+ assert(common->action->kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
+ backup = common->action->drive_backup;
+
+ qmp_drive_backup(backup->device, backup->target,
+ backup->has_format, backup->format,
+ backup->has_mode, backup->mode,
+ backup->has_speed, backup->speed,
+ &local_err);
+ if (error_is_set(&local_err)) {
+ error_propagate(errp, local_err);
+ state->bs = NULL;
+ state->job = NULL;
+ return;
+ }
+
+ state->bs = bdrv_find(backup->device);
+ state->job = state->bs->job;
+}
+
+static void drive_backup_commit(BlkTransactionState *common)
+{
+ /* Block job has started, nothing to do here */
+}
+
+static void drive_backup_abort(BlkTransactionState *common)
+{
+ DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+ BlockDriverState *bs = state->bs;
+
+ /* Only cancel if it's the job we started */
+ if (bs && bs->job && bs->job == state->job) {
+ block_job_cancel_sync(bs->job);
+ }
+}
+
static const BdrvActionOps actions[] = {
[TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC] = {
.instance_size = sizeof(ExternalSnapshotState),
@@ -933,6 +980,12 @@ static const BdrvActionOps actions[] = {
.commit = external_snapshot_commit,
.abort = external_snapshot_abort,
},
+ [TRANSACTION_ACTION_KIND_DRIVE_BACKUP] = {
+ .instance_size = sizeof(DriveBackupState),
+ .prepare = drive_backup_prepare,
+ .commit = drive_backup_commit,
+ .abort = drive_backup_abort,
+ },
};
/*
diff --git a/qapi-schema.json b/qapi-schema.json
index e716522..114ae50 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1609,6 +1609,29 @@
'*mode': 'NewImageMode' } }
##
+# @DriveBackup
+#
+# @device: the name of the device whose writes should be mirrored.
+#
+# @target: the target of the new image. If the file exists, or if it
+# is a device, the existing file/device will be used as the new
+# destination. If it does not exist, a new file will be created.
+#
+# @format: #optional the format of the new destination, default is to
+# probe if @mode is 'existing', else the format of the source
+#
+# @mode: #optional whether and how QEMU should create a new image, default is
+# 'absolute-paths'.
+#
+# @speed: #optional the maximum speed, in bytes per second
+#
+# Since: 1.6
+##
+{ 'type': 'DriveBackup',
+ 'data': { 'device': 'str', 'target': 'str', '*format': 'str',
+ '*mode': 'NewImageMode', '*speed': 'int' } }
+
+##
# @TransactionAction
#
# A discriminated record of operations that can be performed with
@@ -1616,7 +1639,8 @@
##
{ 'union': 'TransactionAction',
'data': {
- 'blockdev-snapshot-sync': 'BlockdevSnapshot'
+ 'blockdev-snapshot-sync': 'BlockdevSnapshot',
+ 'drive-backup': 'DriveBackup'
} }
##
--
1.8.1.4
