block: Add blockdev-backup to transaction

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1418899027-8445-4-git-send-email-famz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

blockdev.c

@@ -1559,6 +1559,79 @@ static void drive_backup_clean(BlkTransactionState *common)
     }
 }
 
+typedef struct BlockdevBackupState {
+    BlkTransactionState common;
+    BlockDriverState *bs;
+    BlockJob *job;
+    AioContext *aio_context;
+} BlockdevBackupState;
+
+static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
+    BlockdevBackup *backup;
+    BlockDriverState *bs, *target;
+    Error *local_err = NULL;
+
+    assert(common->action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
+    backup = common->action->blockdev_backup;
+
+    bs = bdrv_find(backup->device);
+    if (!bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, backup->device);
+        return;
+    }
+
+    target = bdrv_find(backup->target);
+    if (!target) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, backup->target);
+        return;
+    }
+
+    /* AioContext is released in .clean() */
+    state->aio_context = bdrv_get_aio_context(bs);
+    if (state->aio_context != bdrv_get_aio_context(target)) {
+        state->aio_context = NULL;
+        error_setg(errp, "Backup between two IO threads is not implemented");
+        return;
+    }
+    aio_context_acquire(state->aio_context);
+
+    qmp_blockdev_backup(backup->device, backup->target,
+                        backup->sync,
+                        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 (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    state->bs = bs;
+    state->job = state->bs->job;
+}
+
+static void blockdev_backup_abort(BlkTransactionState *common)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, 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 void blockdev_backup_clean(BlkTransactionState *common)
+{
+    BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
+
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
+}
+
 static void abort_prepare(BlkTransactionState *common, Error **errp)
 {
     error_setg(errp, "Transaction aborted using Abort action");
@@ -1582,6 +1655,12 @@ static const BdrvActionOps actions[] = {
         .abort = drive_backup_abort,
         .clean = drive_backup_clean,
     },
+    [TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP] = {
+        .instance_size = sizeof(BlockdevBackupState),
+        .prepare = blockdev_backup_prepare,
+        .abort = blockdev_backup_abort,
+        .clean = blockdev_backup_clean,
+    },
     [TRANSACTION_ACTION_KIND_ABORT] = {
         .instance_size = sizeof(BlkTransactionState),
         .prepare = abort_prepare,

qapi-schema.json

@@ -1260,11 +1260,13 @@
 # drive-backup since 1.6
 # abort since 1.6
 # blockdev-snapshot-internal-sync since 1.7
+# blockdev-backup since 2.3
 ##
 { 'union': 'TransactionAction',
   'data': {
        'blockdev-snapshot-sync': 'BlockdevSnapshot',
        'drive-backup': 'DriveBackup',
+       'blockdev-backup': 'BlockdevBackup',
        'abort': 'Abort',
        'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal'
    } }