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[Qemu-devel] [PATCH v6 09/12] blockdev: add DriveBackup transaction
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v6 09/12] blockdev: add DriveBackup transaction |
Date: |
Mon, 24 Jun 2013 17:13:17 +0200 |
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.
@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
@on-source-error: #optional the action to take on an error on the source,
default 'report'. 'stop' and 'enospc' can only be used
if the block device supports io-status (see BlockInfo).
@on-target-error: #optional the action to take on an error on the target,
default 'report' (no limitations, since this applies to
a different block device than @device).
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Kevin Wolf <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
blockdev.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
qapi-schema.json | 40 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 88 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 8dc6f2e..8caeac4 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -919,6 +919,50 @@ 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,
+ backup->has_on_source_error, backup->on_source_error,
+ backup->has_on_target_error, backup->on_target_error,
+ &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_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),
@@ -926,6 +970,11 @@ 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,
+ .abort = drive_backup_abort,
+ },
};
/*
diff --git a/qapi-schema.json b/qapi-schema.json
index 8dc9471..f3f6ff6 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1615,6 +1615,43 @@
'*mode': 'NewImageMode' } }
##
+# @DriveBackup
+#
+# @device: the name of the device which should be copied.
+#
+# @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
+#
+# @on-source-error: #optional the action to take on an error on the source,
+# default 'report'. 'stop' and 'enospc' can only be used
+# if the block device supports io-status (see BlockInfo).
+#
+# @on-target-error: #optional the action to take on an error on the target,
+# default 'report' (no limitations, since this applies to
+# a different block device than @device).
+#
+# Note that @on-source-error and @on-target-error only affect background I/O.
+# If an error occurs during a guest write request, the device's rerror/werror
+# actions will be used.
+#
+# Since: 1.6
+##
+{ 'type': 'DriveBackup',
+ 'data': { 'device': 'str', 'target': 'str', '*format': 'str',
+ '*mode': 'NewImageMode', '*speed': 'int',
+ '*on-source-error': 'BlockdevOnError',
+ '*on-target-error': 'BlockdevOnError' } }
+
+##
# @TransactionAction
#
# A discriminated record of operations that can be performed with
@@ -1622,7 +1659,8 @@
##
{ 'union': 'TransactionAction',
'data': {
- 'blockdev-snapshot-sync': 'BlockdevSnapshot'
+ 'blockdev-snapshot-sync': 'BlockdevSnapshot',
+ 'drive-backup': 'DriveBackup'
} }
##
--
1.8.1.4
- [Qemu-devel] [PATCH v6 00/12] block: drive-backup live backup command, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 01/12] notify: add NotiferWithReturn so notifier list can abort, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 09/12] blockdev: add DriveBackup transaction,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v6 08/12] blockdev: allow BdrvActionOps->commit() to be NULL, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 03/12] block: add basic backup support to block driver, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 10/12] blockdev: add Abort transaction, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 11/12] qemu-iotests: extract wait_until_completed() into iotests.py, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 05/12] blockdev: use bdrv_getlength() in qmp_drive_mirror(), Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 02/12] block: add bdrv_add_before_write_notifier(), Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 04/12] blockdev: drop redundant proto_drv check, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 06/12] block: add drive-backup QMP command, Stefan Hajnoczi, 2013/06/24
- [Qemu-devel] [PATCH v6 07/12] blockdev: rename BlkTransactionStates to singular, Stefan Hajnoczi, 2013/06/24