From 3037f36446eb3556c14757ac468463c3902f331b Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 24 Jun 2013 17:13:17 +0200 Subject: blockdev: add DriveBackup transaction 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 Reviewed-by: Kevin Wolf Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- blockdev.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ qapi-schema.json | 40 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 88 insertions(+), 1 deletion(-) diff --git a/blockdev.c b/blockdev.c index 0cf80810f5..6200c0dc0a 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 6fe7efc65a..714108dc12 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -1622,6 +1622,43 @@ 'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str', '*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 # @@ -1630,7 +1667,8 @@ ## { 'union': 'TransactionAction', 'data': { - 'blockdev-snapshot-sync': 'BlockdevSnapshot' + 'blockdev-snapshot-sync': 'BlockdevSnapshot', + 'drive-backup': 'DriveBackup' } } ## -- cgit v1.2.1