static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) { BlockDriverState *source = s->common.bs; int nb_sectors, sectors_per_chunk, nb_chunks; int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; uint64_t delay_ns = 0; MirrorOp *op; int pnum; int64_t ret; s->sector_num = hbitmap_iter_next(&s->hbi); if (s->sector_num < 0) { bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); s->sector_num = hbitmap_iter_next(&s->hbi); trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); assert(s->sector_num >= 0); } hbitmap_next_sector = s->sector_num; sector_num = s->sector_num; sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; end = s->bdev_length / BDRV_SECTOR_SIZE; /* Extend the QEMUIOVector to include all adjacent blocks that will * be copied in this operation. * * We have to do this if we have no backing file yet in the destination, * and the cluster size is very large. Then we need to do COW ourselves. * The first time a cluster is copied, copy it entirely. Note that, * because both the granularity and the cluster size are powers of two, * the number of sectors to copy cannot exceed one cluster. * * We also want to extend the QEMUIOVector to include more adjacent * dirty blocks if possible, to limit the number of I/O operations and * run efficiently even with a small granularity. */ nb_chunks = 0; nb_sectors = 0; next_sector = sector_num; next_chunk = sector_num / sectors_per_chunk; /* Wait for I/O to this cluster (from a previous iteration) to be done. */ while (test_bit(next_chunk, s->in_flight_bitmap)) { trace_mirror_yield_in_flight(s, sector_num, s->in_flight); s->waiting_for_io = true; qemu_coroutine_yield(); s->waiting_for_io = false; } do { int added_sectors, added_chunks; if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) || test_bit(next_chunk, s->in_flight_bitmap)) { assert(nb_sectors > 0); break; } added_sectors = sectors_per_chunk; if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) { bdrv_round_to_clusters(s->target, next_sector, added_sectors, &next_sector, &added_sectors); /* On the first iteration, the rounding may make us copy * sectors before the first dirty one. */ if (next_sector < sector_num) { assert(nb_sectors == 0); sector_num = next_sector; next_chunk = next_sector / sectors_per_chunk; } } added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors)); added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk; /* When doing COW, it may happen that there is not enough space for * a full cluster. Wait if that is the case. */ while (nb_chunks == 0 && s->buf_free_count < added_chunks) { trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight); s->waiting_for_io = true; qemu_coroutine_yield(); s->waiting_for_io = false; } if (s->buf_free_count < nb_chunks + added_chunks) { trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); break; } if (IOV_MAX < nb_chunks + added_chunks) { trace_mirror_break_iov_max(s, nb_chunks, added_chunks); break; } /* We have enough free space to copy these sectors. */ bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); nb_sectors += added_sectors; nb_chunks += added_chunks; next_sector += added_sectors; next_chunk += added_chunks; if (!s->synced && s->common.speed) { delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); } } while (delay_ns == 0 && next_sector < end); /* Allocate a MirrorOp that is used as an AIO callback. */ op = g_new(MirrorOp, 1); op->s = s; op->sector_num = sector_num; op->nb_sectors = nb_sectors; /* Now make a QEMUIOVector taking enough granularity-sized chunks * from s->buf_free. */ qemu_iovec_init(&op->qiov, nb_chunks); next_sector = sector_num; while (nb_chunks-- > 0) { MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size; QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); s->buf_free_count--; qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); /* Advance the HBitmapIter in parallel, so that we do not examine * the same sector twice. */ if (next_sector > hbitmap_next_sector && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { hbitmap_next_sector = hbitmap_iter_next(&s->hbi); } next_sector += sectors_per_chunk; } bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors); /* Copy the dirty cluster. */ s->in_flight++; s->sectors_in_flight += nb_sectors; trace_mirror_one_iteration(s, sector_num, nb_sectors); ret = bdrv_get_block_status_above(source, NULL, sector_num, nb_sectors, &pnum); if (ret < 0 || pnum < nb_sectors || (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, mirror_read_complete, op); } else if (ret & BDRV_BLOCK_ZERO) { bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, s->unmap ? BDRV_REQ_MAY_UNMAP : 0, mirror_write_complete, op); } else { assert(!(ret & BDRV_BLOCK_DATA)); bdrv_aio_discard(s->target, sector_num, op->nb_sectors, mirror_write_complete, op); } return delay_ns; }
static void coroutine_fn mirror_iteration(MirrorBlockJob *s) { BlockDriverState *source = s->common.bs; int nb_sectors, sectors_per_chunk, nb_chunks; int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; MirrorOp *op; s->sector_num = hbitmap_iter_next(&s->hbi); if (s->sector_num < 0) { bdrv_dirty_iter_init(source, &s->hbi); s->sector_num = hbitmap_iter_next(&s->hbi); trace_mirror_restart_iter(s, bdrv_get_dirty_count(source)); assert(s->sector_num >= 0); } hbitmap_next_sector = s->sector_num; sector_num = s->sector_num; sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; end = s->common.len >> BDRV_SECTOR_BITS; /* Extend the QEMUIOVector to include all adjacent blocks that will * be copied in this operation. * * We have to do this if we have no backing file yet in the destination, * and the cluster size is very large. Then we need to do COW ourselves. * The first time a cluster is copied, copy it entirely. Note that, * because both the granularity and the cluster size are powers of two, * the number of sectors to copy cannot exceed one cluster. * * We also want to extend the QEMUIOVector to include more adjacent * dirty blocks if possible, to limit the number of I/O operations and * run efficiently even with a small granularity. */ nb_chunks = 0; nb_sectors = 0; next_sector = sector_num; next_chunk = sector_num / sectors_per_chunk; /* Wait for I/O to this cluster (from a previous iteration) to be done. */ while (test_bit(next_chunk, s->in_flight_bitmap)) { trace_mirror_yield_in_flight(s, sector_num, s->in_flight); qemu_coroutine_yield(); } do { int added_sectors, added_chunks; if (!bdrv_get_dirty(source, next_sector) || test_bit(next_chunk, s->in_flight_bitmap)) { assert(nb_sectors > 0); break; } added_sectors = sectors_per_chunk; if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) { bdrv_round_to_clusters(s->target, next_sector, added_sectors, &next_sector, &added_sectors); /* On the first iteration, the rounding may make us copy * sectors before the first dirty one. */ if (next_sector < sector_num) { assert(nb_sectors == 0); sector_num = next_sector; next_chunk = next_sector / sectors_per_chunk; } } added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors)); added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk; /* When doing COW, it may happen that there is not enough space for * a full cluster. Wait if that is the case. */ while (nb_chunks == 0 && s->buf_free_count < added_chunks) { trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight); qemu_coroutine_yield(); } if (s->buf_free_count < nb_chunks + added_chunks) { trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); break; } /* We have enough free space to copy these sectors. */ bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); nb_sectors += added_sectors; nb_chunks += added_chunks; next_sector += added_sectors; next_chunk += added_chunks; } while (next_sector < end); /* Allocate a MirrorOp that is used as an AIO callback. */ op = g_slice_new(MirrorOp); op->s = s; op->sector_num = sector_num; op->nb_sectors = nb_sectors; /* Now make a QEMUIOVector taking enough granularity-sized chunks * from s->buf_free. */ qemu_iovec_init(&op->qiov, nb_chunks); next_sector = sector_num; while (nb_chunks-- > 0) { MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); s->buf_free_count--; qemu_iovec_add(&op->qiov, buf, s->granularity); /* Advance the HBitmapIter in parallel, so that we do not examine * the same sector twice. */ if (next_sector > hbitmap_next_sector && bdrv_get_dirty(source, next_sector)) { hbitmap_next_sector = hbitmap_iter_next(&s->hbi); } next_sector += sectors_per_chunk; } bdrv_reset_dirty(source, sector_num, nb_sectors); /* Copy the dirty cluster. */ s->in_flight++; trace_mirror_one_iteration(s, sector_num, nb_sectors); bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, mirror_read_complete, op); }
static void coroutine_fn mirror_run(void *opaque) { MirrorBlockJob *s = opaque; BlockDriverState *bs = s->common.bs; int64_t sector_num, end, sectors_per_chunk, length; uint64_t last_pause_ns; BlockDriverInfo bdi; char backing_filename[1024]; int ret = 0; int n; if (block_job_is_cancelled(&s->common)) { goto immediate_exit; } s->common.len = bdrv_getlength(bs); if (s->common.len <= 0) { block_job_completed(&s->common, s->common.len); return; } length = (bdrv_getlength(bs) + s->granularity - 1) / 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(s->target, backing_filename, sizeof(backing_filename)); if (backing_filename[0] && !s->target->backing_hd) { bdrv_get_info(s->target, &bdi); if (s->granularity < bdi.cluster_size) { s->buf_size = MAX(s->buf_size, bdi.cluster_size); s->cow_bitmap = bitmap_new(length); } } end = s->common.len >> BDRV_SECTOR_BITS; s->buf = qemu_blockalign(bs, s->buf_size); sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; mirror_free_init(s); if (s->mode != MIRROR_SYNC_MODE_NONE) { /* First part, loop on the sectors and initialize the dirty bitmap. */ BlockDriverState *base; base = s->mode == MIRROR_SYNC_MODE_FULL ? NULL : bs->backing_hd; for (sector_num = 0; sector_num < end; ) { int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1; ret = bdrv_is_allocated_above(bs, base, sector_num, next - sector_num, &n); if (ret < 0) { goto immediate_exit; } assert(n > 0); if (ret == 1) { bdrv_set_dirty(bs, sector_num, n); sector_num = next; } else { sector_num += n; } } } bdrv_dirty_iter_init(bs, &s->hbi); last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); for (;;) { uint64_t delay_ns; int64_t cnt; bool should_complete; if (s->ret < 0) { ret = s->ret; goto immediate_exit; } cnt = bdrv_get_dirty_count(bs); /* Note that even when no rate limit is applied we need to yield * periodically with no pending I/O so that qemu_aio_flush() returns. * We do so every SLICE_TIME nanoseconds, or when there is an error, * or when the source is clean, whichever comes first. */ if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < 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); qemu_coroutine_yield(); continue; } else if (cnt != 0) { mirror_iteration(s); continue; } } should_complete = false; if (s->in_flight == 0 && cnt == 0) { trace_mirror_before_flush(s); ret = bdrv_flush(s->target); if (ret < 0) { if (mirror_error_action(s, false, -ret) == BDRV_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. */ s->common.offset = end * BDRV_SECTOR_SIZE; if (!s->synced) { block_job_ready(&s->common); s->synced = true; } should_complete = s->should_complete || block_job_is_cancelled(&s->common); cnt = bdrv_get_dirty_count(bs); } } 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_drain_all(); cnt = bdrv_get_dirty_count(bs); } ret = 0; trace_mirror_before_sleep(s, cnt, s->synced); if (!s->synced) { /* Publish progress */ s->common.offset = (end - cnt) * BDRV_SECTOR_SIZE; if (s->common.speed) { delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk); } else { delay_ns = 0; } 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; } 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_set_dirty_tracking(bs, 0); bdrv_iostatus_disable(s->target); if (s->should_complete && ret == 0) { if (bdrv_get_flags(s->target) != bdrv_get_flags(s->common.bs)) { bdrv_reopen(s->target, bdrv_get_flags(s->common.bs), NULL); } bdrv_swap(s->target, s->common.bs); } bdrv_close(s->target); bdrv_unref(s->target); block_job_completed(&s->common, ret); }
static void coroutine_fn mirror_run(void *opaque) { MirrorBlockJob *s = opaque; MirrorExitData *data; BlockDriverState *bs = s->common.bs; int64_t sector_num, end, sectors_per_chunk, length; uint64_t last_pause_ns; BlockDriverInfo bdi; char backing_filename[2]; /* we only need 2 characters because we are only checking for a NULL string */ int ret = 0; int n; 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(s->target, backing_filename, sizeof(backing_filename)); if (backing_filename[0] && !s->target->backing_hd) { ret = bdrv_get_info(s->target, &bdi); if (ret < 0) { goto immediate_exit; } if (s->granularity < bdi.cluster_size) { s->buf_size = MAX(s->buf_size, bdi.cluster_size); s->cow_bitmap = bitmap_new(length); } } end = s->bdev_length / BDRV_SECTOR_SIZE; s->buf = qemu_try_blockalign(bs, s->buf_size); if (s->buf == NULL) { ret = -ENOMEM; goto immediate_exit; } sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; mirror_free_init(s); if (!s->is_none_mode) { /* First part, loop on the sectors and initialize the dirty bitmap. */ BlockDriverState *base = s->base; for (sector_num = 0; sector_num < end; ) { int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1; ret = bdrv_is_allocated_above(bs, base, sector_num, next - sector_num, &n); if (ret < 0) { goto immediate_exit; } assert(n > 0); if (ret == 1) { bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); sector_num = next; } else { sector_num += n; } } } bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); for (;;) { uint64_t delay_ns = 0; int64_t cnt; bool should_complete; if (s->ret < 0) { ret = s->ret; goto immediate_exit; } 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. */ if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < 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); qemu_coroutine_yield(); 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 = bdrv_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_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; } 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_release_dirty_bitmap(bs, s->dirty_bitmap); bdrv_iostatus_disable(s->target); data = g_malloc(sizeof(*data)); data->ret = ret; block_job_defer_to_main_loop(&s->common, mirror_exit, data); }