Exemplo n.º 1
0
static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
    BlockDriverState *source = s->source;
    int64_t offset, first_chunk;
    uint64_t delay_ns = 0;
    /* At least the first dirty chunk is mirrored in one iteration. */
    int nb_chunks = 1;
    bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
    int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);

    bdrv_dirty_bitmap_lock(s->dirty_bitmap);
    offset = bdrv_dirty_iter_next(s->dbi);
    if (offset < 0) {
        bdrv_set_dirty_iter(s->dbi, 0);
        offset = bdrv_dirty_iter_next(s->dbi);
        trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
        assert(offset >= 0);
    }
    bdrv_dirty_bitmap_unlock(s->dirty_bitmap);

    first_chunk = offset / s->granularity;
    while (test_bit(first_chunk, s->in_flight_bitmap)) {
        trace_mirror_yield_in_flight(s, offset, s->in_flight);
        mirror_wait_for_io(s);
    }

    block_job_pause_point(&s->common);

    /* Find the number of consective dirty chunks following the first dirty
     * one, and wait for in flight requests in them. */
    bdrv_dirty_bitmap_lock(s->dirty_bitmap);
    while (nb_chunks * s->granularity < s->buf_size) {
        int64_t next_dirty;
        int64_t next_offset = offset + nb_chunks * s->granularity;
        int64_t next_chunk = next_offset / s->granularity;
        if (next_offset >= s->bdev_length ||
            !bdrv_get_dirty_locked(source, s->dirty_bitmap, next_offset)) {
            break;
        }
        if (test_bit(next_chunk, s->in_flight_bitmap)) {
            break;
        }

        next_dirty = bdrv_dirty_iter_next(s->dbi);
        if (next_dirty > next_offset || next_dirty < 0) {
            /* The bitmap iterator's cache is stale, refresh it */
            bdrv_set_dirty_iter(s->dbi, next_offset);
            next_dirty = bdrv_dirty_iter_next(s->dbi);
        }
        assert(next_dirty == next_offset);
        nb_chunks++;
    }

    /* Clear dirty bits before querying the block status, because
     * calling bdrv_block_status_above could yield - if some blocks are
     * marked dirty in this window, we need to know.
     */
    bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
                                   nb_chunks * s->granularity);
    bdrv_dirty_bitmap_unlock(s->dirty_bitmap);

    bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
    while (nb_chunks > 0 && offset < s->bdev_length) {
        int ret;
        int64_t io_bytes;
        int64_t io_bytes_acct;
        enum MirrorMethod {
            MIRROR_METHOD_COPY,
            MIRROR_METHOD_ZERO,
            MIRROR_METHOD_DISCARD
        } mirror_method = MIRROR_METHOD_COPY;

        assert(!(offset % s->granularity));
        ret = bdrv_block_status_above(source, NULL, offset,
                                      nb_chunks * s->granularity,
                                      &io_bytes, NULL, NULL);
        if (ret < 0) {
            io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes);
        } else if (ret & BDRV_BLOCK_DATA) {
            io_bytes = MIN(io_bytes, max_io_bytes);
        }

        io_bytes -= io_bytes % s->granularity;
        if (io_bytes < s->granularity) {
            io_bytes = s->granularity;
        } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) {
            int64_t target_offset;
            int64_t target_bytes;
            bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes,
                                   &target_offset, &target_bytes);
            if (target_offset == offset &&
                target_bytes == io_bytes) {
                mirror_method = ret & BDRV_BLOCK_ZERO ?
                                    MIRROR_METHOD_ZERO :
                                    MIRROR_METHOD_DISCARD;
            }
        }

        while (s->in_flight >= MAX_IN_FLIGHT) {
            trace_mirror_yield_in_flight(s, offset, s->in_flight);
            mirror_wait_for_io(s);
        }

        if (s->ret < 0) {
            return 0;
        }

        io_bytes = mirror_clip_bytes(s, offset, io_bytes);
        switch (mirror_method) {
        case MIRROR_METHOD_COPY:
            io_bytes = io_bytes_acct = mirror_do_read(s, offset, io_bytes);
            break;
        case MIRROR_METHOD_ZERO:
        case MIRROR_METHOD_DISCARD:
            mirror_do_zero_or_discard(s, offset, io_bytes,
                                      mirror_method == MIRROR_METHOD_DISCARD);
            if (write_zeroes_ok) {
                io_bytes_acct = 0;
            } else {
                io_bytes_acct = io_bytes;
            }
            break;
        default:
            abort();
        }
        assert(io_bytes);
        offset += io_bytes;
        nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity);
        delay_ns = block_job_ratelimit_get_delay(&s->common, io_bytes_acct);
    }
    return delay_ns;
}
Exemplo n.º 2
0
static void coroutine_fn mirror_run(void *opaque)
{
    MirrorBlockJob *s = opaque;
    MirrorExitData *data;
    BlockDriverState *bs = s->source;
    BlockDriverState *target_bs = blk_bs(s->target);
    bool need_drain = true;
    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;

    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;
    }

    /* Active commit must resize the base image if its size differs from the
     * active layer. */
    if (s->base == blk_bs(s->target)) {
        int64_t base_length;

        base_length = blk_getlength(s->target);
        if (base_length < 0) {
            ret = base_length;
            goto immediate_exit;
        }

        if (s->bdev_length > base_length) {
            ret = blk_truncate(s->target, s->bdev_length, PREALLOC_MODE_OFF,
                               NULL);
            if (ret < 0) {
                goto immediate_exit;
            }
        }
    }

    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) {
        s->target_cluster_size = bdi.cluster_size;
    } else {
        s->target_cluster_size = BDRV_SECTOR_SIZE;
    }
    if (backing_filename[0] && !target_bs->backing &&
        s->granularity < s->target_cluster_size) {
        s->buf_size = MAX(s->buf_size, s->target_cluster_size);
        s->cow_bitmap = bitmap_new(length);
    }
    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);
    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);
        /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
         * the number of bytes currently being processed; together those are
         * the current remaining operation length */
        block_job_progress_set_remaining(&s->common, s->bytes_in_flight + cnt);

        /* 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 BLKOCK_JOB_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 < BLOCK_JOB_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, cnt, s->buf_free_count, s->in_flight);
                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);
            if (!s->synced) {
                if (mirror_flush(s) < 0) {
                    /* Go check s->ret.  */
                    continue;
                }
                /* 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.
                 */
                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, so pause it now.  Before deciding
             * whether to switch to target check one last time if I/O has
             * come in the meanwhile, and if not flush the data to disk.
             */
            trace_mirror_before_drain(s, cnt);

            bdrv_drained_begin(bs);
            cnt = bdrv_get_dirty_count(s->dirty_bitmap);
            if (cnt > 0 || mirror_flush(s) < 0) {
                bdrv_drained_end(bs);
                continue;
            }

            /* The two disks are in sync.  Exit and report successful
             * completion.
             */
            assert(QLIST_EMPTY(&bs->tracked_requests));
            s->common.cancelled = false;
            need_drain = false;
            break;
        }

        ret = 0;

        if (s->synced && !should_complete) {
            delay_ns = (s->in_flight == 0 &&
                        cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0);
        }
        trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
        block_job_sleep_ns(&s->common, delay_ns);
        if (block_job_is_cancelled(&s->common) &&
            (!s->synced || s->common.force))
        {
            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->common.force || !s->synced) &&
               block_job_is_cancelled(&s->common)));
        assert(need_drain);
        mirror_wait_for_all_io(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);

    data = g_malloc(sizeof(*data));
    data->ret = ret;

    if (need_drain) {
        bdrv_drained_begin(bs);
    }
    block_job_defer_to_main_loop(&s->common, mirror_exit, data);
}
Exemplo n.º 3
0
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;
}
Exemplo n.º 4
0
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);
}
Exemplo n.º 5
0
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);
}
Exemplo n.º 6
0
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);
}
Exemplo n.º 7
0
Arquivo: qapi.c Projeto: B-Rich/qemu
/* @p_info will be set only on success. */
void bdrv_query_info(BlockDriverState *bs,
                     BlockInfo **p_info,
                     Error **errp)
{
    BlockInfo *info = g_malloc0(sizeof(*info));
    BlockDriverState *bs0;
    ImageInfo **p_image_info;
    Error *local_err = NULL;
    info->device = g_strdup(bs->device_name);
    info->type = g_strdup("unknown");
    info->locked = bdrv_dev_is_medium_locked(bs);
    info->removable = bdrv_dev_has_removable_media(bs);

    if (bdrv_dev_has_removable_media(bs)) {
        info->has_tray_open = true;
        info->tray_open = bdrv_dev_is_tray_open(bs);
    }

    if (bdrv_iostatus_is_enabled(bs)) {
        info->has_io_status = true;
        info->io_status = bs->iostatus;
    }

    if (bs->dirty_bitmap) {
        info->has_dirty = true;
        info->dirty = g_malloc0(sizeof(*info->dirty));
        info->dirty->count = bdrv_get_dirty_count(bs) * BDRV_SECTOR_SIZE;
        info->dirty->granularity =
         ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bs->dirty_bitmap));
    }

    if (bs->drv) {
        info->has_inserted = true;
        info->inserted = g_malloc0(sizeof(*info->inserted));
        info->inserted->file = g_strdup(bs->filename);
        info->inserted->ro = bs->read_only;
        info->inserted->drv = g_strdup(bs->drv->format_name);
        info->inserted->encrypted = bs->encrypted;
        info->inserted->encryption_key_missing = bdrv_key_required(bs);

        if (bs->backing_file[0]) {
            info->inserted->has_backing_file = true;
            info->inserted->backing_file = g_strdup(bs->backing_file);
        }

        info->inserted->backing_file_depth = bdrv_get_backing_file_depth(bs);

        if (bs->io_limits_enabled) {
            ThrottleConfig cfg;
            throttle_get_config(&bs->throttle_state, &cfg);
            info->inserted->bps     = cfg.buckets[THROTTLE_BPS_TOTAL].avg;
            info->inserted->bps_rd  = cfg.buckets[THROTTLE_BPS_READ].avg;
            info->inserted->bps_wr  = cfg.buckets[THROTTLE_BPS_WRITE].avg;

            info->inserted->iops    = cfg.buckets[THROTTLE_OPS_TOTAL].avg;
            info->inserted->iops_rd = cfg.buckets[THROTTLE_OPS_READ].avg;
            info->inserted->iops_wr = cfg.buckets[THROTTLE_OPS_WRITE].avg;

            info->inserted->has_bps_max     =
                cfg.buckets[THROTTLE_BPS_TOTAL].max;
            info->inserted->bps_max         =
                cfg.buckets[THROTTLE_BPS_TOTAL].max;
            info->inserted->has_bps_rd_max  =
                cfg.buckets[THROTTLE_BPS_READ].max;
            info->inserted->bps_rd_max      =
                cfg.buckets[THROTTLE_BPS_READ].max;
            info->inserted->has_bps_wr_max  =
                cfg.buckets[THROTTLE_BPS_WRITE].max;
            info->inserted->bps_wr_max      =
                cfg.buckets[THROTTLE_BPS_WRITE].max;

            info->inserted->has_iops_max    =
                cfg.buckets[THROTTLE_OPS_TOTAL].max;
            info->inserted->iops_max        =
                cfg.buckets[THROTTLE_OPS_TOTAL].max;
            info->inserted->has_iops_rd_max =
                cfg.buckets[THROTTLE_OPS_READ].max;
            info->inserted->iops_rd_max     =
                cfg.buckets[THROTTLE_OPS_READ].max;
            info->inserted->has_iops_wr_max =
                cfg.buckets[THROTTLE_OPS_WRITE].max;
            info->inserted->iops_wr_max     =
                cfg.buckets[THROTTLE_OPS_WRITE].max;

            info->inserted->has_iops_size = cfg.op_size;
            info->inserted->iops_size = cfg.op_size;
        }

        bs0 = bs;
        p_image_info = &info->inserted->image;
        while (1) {
            bdrv_query_image_info(bs0, p_image_info, &local_err);
            if (error_is_set(&local_err)) {
                error_propagate(errp, local_err);
                goto err;
            }
            if (bs0->drv && bs0->backing_hd) {
                bs0 = bs0->backing_hd;
                (*p_image_info)->has_backing_image = true;
                p_image_info = &((*p_image_info)->backing_image);
            } else {
                break;
            }
        }
    }

    *p_info = info;
    return;

 err:
    qapi_free_BlockInfo(info);
}