static void coroutine_fn mirror_run(void *opaque) { MirrorBlockJob *s = opaque; MirrorExitData *data; BlockDriverState *bs = blk_bs(s->common.blk); BlockDriverState *target_bs = blk_bs(s->target); int64_t length; BlockDriverInfo bdi; char backing_filename[2]; /* we only need 2 characters because we are only checking for a NULL string */ int ret = 0; int target_cluster_size = BDRV_SECTOR_SIZE; if (block_job_is_cancelled(&s->common)) { goto immediate_exit; } s->bdev_length = bdrv_getlength(bs); if (s->bdev_length < 0) { ret = s->bdev_length; goto immediate_exit; } else if (s->bdev_length == 0) { /* Report BLOCK_JOB_READY and wait for complete. */ block_job_event_ready(&s->common); s->synced = true; while (!block_job_is_cancelled(&s->common) && !s->should_complete) { block_job_yield(&s->common); } s->common.cancelled = false; goto immediate_exit; } length = DIV_ROUND_UP(s->bdev_length, s->granularity); s->in_flight_bitmap = bitmap_new(length); /* If we have no backing file yet in the destination, we cannot let * the destination do COW. Instead, we copy sectors around the * dirty data if needed. We need a bitmap to do that. */ bdrv_get_backing_filename(target_bs, backing_filename, sizeof(backing_filename)); if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) { target_cluster_size = bdi.cluster_size; } if (backing_filename[0] && !target_bs->backing && s->granularity < target_cluster_size) { s->buf_size = MAX(s->buf_size, target_cluster_size); s->cow_bitmap = bitmap_new(length); } s->target_cluster_sectors = target_cluster_size >> BDRV_SECTOR_BITS; s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov); s->buf = qemu_try_blockalign(bs, s->buf_size); if (s->buf == NULL) { ret = -ENOMEM; goto immediate_exit; } mirror_free_init(s); s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); if (!s->is_none_mode) { ret = mirror_dirty_init(s); if (ret < 0 || block_job_is_cancelled(&s->common)) { goto immediate_exit; } } assert(!s->dbi); s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0); for (;;) { uint64_t delay_ns = 0; int64_t cnt, delta; bool should_complete; if (s->ret < 0) { ret = s->ret; goto immediate_exit; } block_job_pause_point(&s->common); cnt = bdrv_get_dirty_count(s->dirty_bitmap); /* s->common.offset contains the number of bytes already processed so * far, cnt is the number of dirty sectors remaining and * s->sectors_in_flight is the number of sectors currently being * processed; together those are the current total operation length */ s->common.len = s->common.offset + (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; /* Note that even when no rate limit is applied we need to yield * periodically with no pending I/O so that bdrv_drain_all() returns. * We do so every SLICE_TIME nanoseconds, or when there is an error, * or when the source is clean, whichever comes first. */ delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns; if (delta < SLICE_TIME && s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 || (cnt == 0 && s->in_flight > 0)) { trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); mirror_wait_for_io(s); continue; } else if (cnt != 0) { delay_ns = mirror_iteration(s); } } should_complete = false; if (s->in_flight == 0 && cnt == 0) { trace_mirror_before_flush(s); ret = blk_flush(s->target); if (ret < 0) { if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) { goto immediate_exit; } } else { /* We're out of the streaming phase. From now on, if the job * is cancelled we will actually complete all pending I/O and * report completion. This way, block-job-cancel will leave * the target in a consistent state. */ if (!s->synced) { block_job_event_ready(&s->common); s->synced = true; } should_complete = s->should_complete || block_job_is_cancelled(&s->common); cnt = bdrv_get_dirty_count(s->dirty_bitmap); } } if (cnt == 0 && should_complete) { /* The dirty bitmap is not updated while operations are pending. * If we're about to exit, wait for pending operations before * calling bdrv_get_dirty_count(bs), or we may exit while the * source has dirty data to copy! * * Note that I/O can be submitted by the guest while * mirror_populate runs. */ trace_mirror_before_drain(s, cnt); bdrv_co_drain(bs); cnt = bdrv_get_dirty_count(s->dirty_bitmap); } ret = 0; trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); if (!s->synced) { block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); if (block_job_is_cancelled(&s->common)) { break; } } else if (!should_complete) { delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); } else if (cnt == 0) { /* The two disks are in sync. Exit and report successful * completion. */ assert(QLIST_EMPTY(&bs->tracked_requests)); s->common.cancelled = false; break; } s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); } immediate_exit: if (s->in_flight > 0) { /* We get here only if something went wrong. Either the job failed, * or it was cancelled prematurely so that we do not guarantee that * the target is a copy of the source. */ assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); mirror_drain(s); } assert(s->in_flight == 0); qemu_vfree(s->buf); g_free(s->cow_bitmap); g_free(s->in_flight_bitmap); bdrv_dirty_iter_free(s->dbi); bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); data = g_malloc(sizeof(*data)); data->ret = ret; /* Before we switch to target in mirror_exit, make sure data doesn't * change. */ bdrv_drained_begin(bs); block_job_defer_to_main_loop(&s->common, mirror_exit, data); }