static void coroutine_fn backup_run(void *opaque) { BackupBlockJob *job = opaque; BackupCompleteData *data; BlockDriverState *bs = job->common.bs; BlockDriverState *target = job->target; BlockdevOnError on_target_error = job->on_target_error; NotifierWithReturn before_write = { .notify = backup_before_write_notify, }; int64_t start, end; int ret = 0; QLIST_INIT(&job->inflight_reqs); qemu_co_rwlock_init(&job->flush_rwlock); start = 0; end = DIV_ROUND_UP(job->common.len / BDRV_SECTOR_SIZE, BACKUP_SECTORS_PER_CLUSTER); job->bitmap = hbitmap_alloc(end, 0); bdrv_set_enable_write_cache(target, true); bdrv_set_on_error(target, on_target_error, on_target_error); bdrv_iostatus_enable(target); bdrv_add_before_write_notifier(bs, &before_write); if (job->sync_mode == MIRROR_SYNC_MODE_NONE) { while (!block_job_is_cancelled(&job->common)) { /* Yield until the job is cancelled. We just let our before_write * notify callback service CoW requests. */ job->common.busy = false; qemu_coroutine_yield(); job->common.busy = true; } } else { /* Both FULL and TOP SYNC_MODE's require copying.. */ for (; start < end; start++) { bool error_is_read; if (block_job_is_cancelled(&job->common)) { break; } /* we need to yield so that qemu_aio_flush() returns. * (without, VM does not reboot) */ if (job->common.speed) { uint64_t delay_ns = ratelimit_calculate_delay( &job->limit, job->sectors_read); job->sectors_read = 0; block_job_sleep_ns(&job->common, QEMU_CLOCK_REALTIME, delay_ns); } else { block_job_sleep_ns(&job->common, QEMU_CLOCK_REALTIME, 0); } if (block_job_is_cancelled(&job->common)) { break; } if (job->sync_mode == MIRROR_SYNC_MODE_TOP) { int i, n; int alloced = 0; /* Check to see if these blocks are already in the * backing file. */ for (i = 0; i < BACKUP_SECTORS_PER_CLUSTER;) { /* bdrv_is_allocated() only returns true/false based * on the first set of sectors it comes across that * are are all in the same state. * For that reason we must verify each sector in the * backup cluster length. We end up copying more than * needed but at some point that is always the case. */ alloced = bdrv_is_allocated(bs, start * BACKUP_SECTORS_PER_CLUSTER + i, BACKUP_SECTORS_PER_CLUSTER - i, &n); i += n; if (alloced == 1 || n == 0) { break; } } /* If the above loop never found any sectors that are in * the topmost image, skip this backup. */ if (alloced == 0) { continue; } } /* FULL sync mode we copy the whole drive. */ ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER, BACKUP_SECTORS_PER_CLUSTER, &error_is_read); if (ret < 0) { /* Depending on error action, fail now or retry cluster */ BlockErrorAction action = backup_error_action(job, error_is_read, -ret); if (action == BLOCK_ERROR_ACTION_REPORT) { break; } else { start--; continue; } } } } notifier_with_return_remove(&before_write); /* wait until pending backup_do_cow() calls have completed */ qemu_co_rwlock_wrlock(&job->flush_rwlock); qemu_co_rwlock_unlock(&job->flush_rwlock); hbitmap_free(job->bitmap); bdrv_iostatus_disable(target); data = g_malloc(sizeof(*data)); data->ret = ret; block_job_defer_to_main_loop(&job->common, backup_complete, data); }