C++ qemu_aio_get函数代码示例

/* This is where we get a request from a caller to read something */
static BlockDriverAIOCB *tar_aio_readv(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVTarState *s = bs->opaque;
    SparseCache *sparse;
    int64_t sec_file = sector_num + s->file_sec;
    int64_t start = sector_num * SECTOR_SIZE;
    int64_t end = start + (nb_sectors * SECTOR_SIZE);
    int i;
    TarAIOCB *acb;

    for (i = 0; i < s->sparse_num; i++) {
        sparse = &s->sparse[i];
        if (sparse->start > end) {
            /* We expect the cache to be start increasing */
            break;
        } else if ((sparse->start < start) && (sparse->end <= start)) {
            /* sparse before our offset */
            sec_file -= (sparse->end - sparse->start) / SECTOR_SIZE;
        } else if ((sparse->start <= start) && (sparse->end >= end)) {
            /* all our sectors are sparse */
            char *buf = g_malloc0(nb_sectors * SECTOR_SIZE);

            acb = qemu_aio_get(&tar_aiocb_info, bs, cb, opaque);
            qemu_iovec_from_buf(qiov, 0, buf, nb_sectors * SECTOR_SIZE);
            g_free(buf);
            acb->bh = qemu_bh_new(tar_sparse_cb, acb);
            qemu_bh_schedule(acb->bh);

            return &acb->common;
        } else if (((sparse->start >= start) && (sparse->start < end)) ||
                   ((sparse->end >= start) && (sparse->end < end))) {
            /* we're semi-sparse (worst case) */
            /* let's go synchronous and read all sectors individually */
            char *buf = g_malloc(nb_sectors * SECTOR_SIZE);
            uint64_t offs;

            for (offs = 0; offs < (nb_sectors * SECTOR_SIZE);
                 offs += SECTOR_SIZE) {
                bdrv_pread(bs, (sector_num * SECTOR_SIZE) + offs,
                           buf + offs, SECTOR_SIZE);
            }

            qemu_iovec_from_buf(qiov, 0, buf, nb_sectors * SECTOR_SIZE);
            acb = qemu_aio_get(&tar_aiocb_info, bs, cb, opaque);
            acb->bh = qemu_bh_new(tar_sparse_cb, acb);
            qemu_bh_schedule(acb->bh);

            return &acb->common;
        }
    }

    return bdrv_aio_readv(s->hd, sec_file, qiov, nb_sectors,
                          cb, opaque);
}

static BlockDriverAIOCB *
iscsi_aio_flush(BlockDriverState *bs,
                BlockDriverCompletionFunc *cb, void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = iscsilun->iscsi;
    IscsiAIOCB *acb;

    acb = qemu_aio_get(&iscsi_aio_pool, bs, cb, opaque);

    acb->iscsilun = iscsilun;
    acb->canceled   = 0;

    acb->task = iscsi_synchronizecache10_task(iscsi, iscsilun->lun,
                                         0, 0, 0, 0,
                                         iscsi_synccache10_cb,
                                         acb);
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to send synchronizecache10 command. %s",
                     iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}

static BlockDriverAIOCB *
iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
                QEMUIOVector *qiov, int nb_sectors,
                BlockDriverCompletionFunc *cb,
                void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    IscsiAIOCB *acb;

    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
    trace_iscsi_aio_readv(iscsilun->iscsi, sector_num, nb_sectors, opaque, acb);

    acb->nb_sectors  = nb_sectors;
    acb->sector_num  = sector_num;
    acb->iscsilun    = iscsilun;
    acb->qiov        = qiov;
    acb->read_size   = BDRV_SECTOR_SIZE * (size_t)acb->nb_sectors;
    acb->retries     = ISCSI_CMD_RETRIES;

    if (iscsi_aio_readv_acb(acb) != 0) {
        if (acb->task) {
            scsi_free_scsi_task(acb->task);
        }
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);
    return &acb->common;
}

static RawAIOCB *raw_aio_setup(BlockDriverState *bs,
        int64_t sector_num, uint8_t *buf, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVRawState *s = bs->opaque;
    RawAIOCB *acb;

    if (fd_open(bs) < 0)
        return NULL;

    acb = qemu_aio_get(bs, cb, opaque);
    if (!acb)
        return NULL;
    acb->aiocb.aio_fildes = s->fd;
    acb->aiocb.ev_signo = SIGUSR2;
    acb->aiocb.aio_buf = buf;
    if (nb_sectors < 0)
        acb->aiocb.aio_nbytes = -nb_sectors;
    else
        acb->aiocb.aio_nbytes = nb_sectors * 512;
    acb->aiocb.aio_offset = sector_num * 512;
    acb->next = posix_aio_state->first_aio;
    posix_aio_state->first_aio = acb;
    return acb;
}

static BlockDriverAIOCB *qemu_gluster_aio_discard(BlockDriverState *bs,
        int64_t sector_num, int nb_sectors, BlockDriverCompletionFunc *cb,
        void *opaque)
{
    int ret;
    GlusterAIOCB *acb;
    BDRVGlusterState *s = bs->opaque;
    size_t size;
    off_t offset;

    offset = sector_num * BDRV_SECTOR_SIZE;
    size = nb_sectors * BDRV_SECTOR_SIZE;

    acb = qemu_aio_get(&gluster_aiocb_info, bs, cb, opaque);
    acb->size = 0;
    acb->ret = 0;
    acb->finished = NULL;

    ret = glfs_discard_async(s->fd, offset, size, &gluster_finish_aiocb, acb);
    if (ret < 0) {
        goto out;
    }
    return &acb->common;

out:
    qemu_aio_release(acb);
    return NULL;
}

static RawAIOCB *raw_aio_setup(BlockDriverState *bs, int64_t sector_num,
        QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVRawState *s = bs->opaque;
    RawAIOCB *acb;

    if (fd_open(bs) < 0)
        return NULL;

    acb = qemu_aio_get(&raw_aio_pool, bs, cb, opaque);
    if (!acb)
        return NULL;
    acb->aiocb.aio_fildes = s->fd;
    acb->aiocb.ev_signo = SIGUSR2;
    acb->aiocb.aio_iov = qiov->iov;
    acb->aiocb.aio_niov = qiov->niov;
    acb->aiocb.aio_nbytes = nb_sectors * 512;
    acb->aiocb.aio_offset = sector_num * 512;
    acb->aiocb.aio_flags = 0;

    /*
     * If O_DIRECT is used the buffer needs to be aligned on a sector
     * boundary. Tell the low level code to ensure that in case it's
     * not done yet.
     */
    if (s->aligned_buf)
        acb->aiocb.aio_flags |= QEMU_AIO_SECTOR_ALIGNED;

    acb->next = posix_aio_state->first_aio;
    posix_aio_state->first_aio = acb;
    return acb;
}

static BlockDriverAIOCB *
iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
                QEMUIOVector *qiov, int nb_sectors,
                BlockDriverCompletionFunc *cb,
                void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    IscsiAIOCB *acb;

    if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
        return NULL;
    }

    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
    trace_iscsi_aio_readv(iscsilun->iscsi, sector_num, nb_sectors, opaque, acb);

    acb->nb_sectors  = nb_sectors;
    acb->sector_num  = sector_num;
    acb->iscsilun    = iscsilun;
    acb->qiov        = qiov;
    acb->retries     = ISCSI_CMD_RETRIES;

    if (iscsi_aio_readv_acb(acb) != 0) {
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);
    return &acb->common;
}

static BlockDriverAIOCB *
iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
                QEMUIOVector *qiov, int nb_sectors,
                BlockDriverCompletionFunc *cb,
                void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = iscsilun->iscsi;
    IscsiAIOCB *acb;
    size_t qemu_read_size, lun_read_size;
    int i;

    qemu_read_size = BDRV_SECTOR_SIZE * (size_t)nb_sectors;

    acb = qemu_aio_get(&iscsi_aio_pool, bs, cb, opaque);
    trace_iscsi_aio_readv(iscsi, sector_num, nb_sectors, opaque, acb);

    acb->iscsilun = iscsilun;
    acb->qiov     = qiov;

    acb->canceled    = 0;
    acb->read_size   = qemu_read_size;
    acb->buf         = NULL;

    /* If LUN blocksize is bigger than BDRV_BLOCK_SIZE a read from QEMU
     * may be misaligned to the LUN, so we may need to read some extra
     * data.
     */
    acb->read_offset = 0;
    if (iscsilun->block_size > BDRV_SECTOR_SIZE) {
        uint64_t bdrv_offset = BDRV_SECTOR_SIZE * sector_num;

        acb->read_offset  = bdrv_offset % iscsilun->block_size;
    }

    lun_read_size  = (qemu_read_size + iscsilun->block_size
                     + acb->read_offset - 1)
                     / iscsilun->block_size * iscsilun->block_size;
    acb->task = iscsi_read10_task(iscsi, iscsilun->lun,
                             sector_qemu2lun(sector_num, iscsilun),
                             lun_read_size, iscsilun->block_size,
                             0, 0, 0, 0, 0,
                             iscsi_aio_read10_cb, acb);
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to send read10 command. %s",
                     iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }

    for (i = 0; i < acb->qiov->niov; i++) {
        scsi_task_add_data_in_buffer(acb->task,
                acb->qiov->iov[i].iov_len,
                acb->qiov->iov[i].iov_base);
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}

static BlockDriverAIOCB *
iscsi_aio_discard(BlockDriverState *bs,
                  int64_t sector_num, int nb_sectors,
                  BlockDriverCompletionFunc *cb, void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    IscsiAIOCB *acb;

    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    acb->iscsilun    = iscsilun;
    acb->nb_sectors  = nb_sectors;
    acb->sector_num  = sector_num;
    acb->retries     = ISCSI_CMD_RETRIES;

    if (iscsi_aio_discard_acb(acb) != 0) {
        if (acb->task) {
            scsi_free_scsi_task(acb->task);
        }
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}

static BlockDriverAIOCB *
iscsi_aio_discard(BlockDriverState *bs,
                  int64_t sector_num, int nb_sectors,
                  BlockDriverCompletionFunc *cb, void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = iscsilun->iscsi;
    IscsiAIOCB *acb;
    struct unmap_list list[1];

    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    acb->iscsilun = iscsilun;
    acb->canceled   = 0;
    acb->bh         = NULL;
    acb->status     = -EINPROGRESS;

    list[0].lba = sector_qemu2lun(sector_num, iscsilun);
    list[0].num = nb_sectors * BDRV_SECTOR_SIZE / iscsilun->block_size;

    acb->task = iscsi_unmap_task(iscsi, iscsilun->lun,
                                 0, 0, &list[0], 1,
                                 iscsi_unmap_cb,
                                 acb);
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to send unmap command. %s",
                     iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}

static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    BDRVCURLState *s = bs->opaque;
    CURLAIOCB *acb;
    size_t start = sector_num * SECTOR_SIZE;
    size_t end;
    CURLState *state;

    acb = qemu_aio_get(&curl_aio_pool, bs, cb, opaque);
    if (!acb)
        return NULL;

    acb->qiov = qiov;

    // In case we have the requested data already (e.g. read-ahead),
    // we can just call the callback and be done.

    switch (curl_find_buf(s, start, nb_sectors * SECTOR_SIZE, acb)) {
        case FIND_RET_OK:
            qemu_aio_release(acb);
            // fall through
        case FIND_RET_WAIT:
            return &acb->common;
        default:
            break;
    }

    // No cache found, so let's start a new request

    state = curl_init_state(s);
    if (!state)
        return NULL;

    acb->start = 0;
    acb->end = (nb_sectors * SECTOR_SIZE);

    state->buf_off = 0;
    if (state->orig_buf)
        g_free(state->orig_buf);
    state->buf_start = start;
    state->buf_len = acb->end + s->readahead_size;
    end = MIN(start + state->buf_len, s->len) - 1;
    state->orig_buf = g_malloc(state->buf_len);
    state->acb[0] = acb;

    snprintf(state->range, 127, "%zd-%zd", start, end);
    DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
            (nb_sectors * SECTOR_SIZE), start, state->range);
    curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);

    curl_multi_add_handle(s->multi, state->curl);
    curl_multi_do(s);

    return &acb->common;
}

BlockDriverAIOCB *win32_aio_submit(BlockDriverState *bs,
        QEMUWin32AIOState *aio, HANDLE hfile,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque, int type)
{
    struct QEMUWin32AIOCB *waiocb;
    uint64_t offset = sector_num * 512;
    DWORD rc;

    waiocb = qemu_aio_get(&win32_aiocb_info, bs, cb, opaque);
    waiocb->nbytes = nb_sectors * 512;
    waiocb->qiov = qiov;
    waiocb->is_read = (type == QEMU_AIO_READ);

    if (qiov->niov > 1) {
        waiocb->buf = qemu_try_blockalign(bs, qiov->size);
        if (waiocb->buf == NULL) {
            goto out;
        }
        if (type & QEMU_AIO_WRITE) {
            iov_to_buf(qiov->iov, qiov->niov, 0, waiocb->buf, qiov->size);
        }
        waiocb->is_linear = false;
    } else {
        waiocb->buf = qiov->iov[0].iov_base;
        waiocb->is_linear = true;
    }

    memset(&waiocb->ov, 0, sizeof(waiocb->ov));
    waiocb->ov.Offset = (DWORD)offset;
    waiocb->ov.OffsetHigh = (DWORD)(offset >> 32);
    waiocb->ov.hEvent = event_notifier_get_handle(&aio->e);

    aio->count++;

    if (type & QEMU_AIO_READ) {
        rc = ReadFile(hfile, waiocb->buf, waiocb->nbytes, NULL, &waiocb->ov);
    } else {
        rc = WriteFile(hfile, waiocb->buf, waiocb->nbytes, NULL, &waiocb->ov);
    }
    if(rc == 0 && GetLastError() != ERROR_IO_PENDING) {
        goto out_dec_count;
    }
    return &waiocb->common;

out_dec_count:
    aio->count--;
out:
    qemu_aio_release(waiocb);
    return NULL;
}

static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    CURLAIOCB *acb;

    acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);

    acb->qiov = qiov;
    acb->sector_num = sector_num;
    acb->nb_sectors = nb_sectors;

    acb->bh = qemu_bh_new(curl_readv_bh_cb, acb);
    qemu_bh_schedule(acb->bh);
    return &acb->common;
}

static BlockDriverAIOCB *
iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
                 QEMUIOVector *qiov, int nb_sectors,
                 BlockDriverCompletionFunc *cb,
                 void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = iscsilun->iscsi;
    IscsiAIOCB *acb;
    size_t size;
    int fua = 0;

    /* set FUA on writes when cache mode is write through */
    if (!(bs->open_flags & BDRV_O_CACHE_WB)) {
        fua = 1;
    }

    acb = qemu_aio_get(&iscsi_aio_pool, bs, cb, opaque);
    trace_iscsi_aio_writev(iscsi, sector_num, nb_sectors, opaque, acb);

    acb->iscsilun = iscsilun;
    acb->qiov     = qiov;

    acb->canceled   = 0;

    /* XXX we should pass the iovec to write10 to avoid the extra copy */
    /* this will allow us to get rid of 'buf' completely */
    size = nb_sectors * BDRV_SECTOR_SIZE;
    acb->buf = g_malloc(size);
    qemu_iovec_to_buffer(acb->qiov, acb->buf);
    acb->task = iscsi_write10_task(iscsi, iscsilun->lun,
                              sector_qemu2lun(sector_num, iscsilun),
                              acb->buf, size, iscsilun->block_size,
                              0, 0, fua, 0, 0,
                              iscsi_aio_write10_cb, acb);
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to send write10 command. %s",
                     iscsi_get_error(iscsi));
        g_free(acb->buf);
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}

BlockAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockCompletionFunc *cb, void *opaque, int type)
{
    struct qemu_laio_state *s = aio_ctx;
    struct qemu_laiocb *laiocb;
    struct iocb *iocbs;
    off_t offset = sector_num * 512;

    laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
    laiocb->nbytes = nb_sectors * 512;
    laiocb->ctx = s;
    laiocb->ret = -EINPROGRESS;
    laiocb->is_read = (type == QEMU_AIO_READ);
    laiocb->qiov = qiov;

    iocbs = &laiocb->iocb;

    switch (type) {
    case QEMU_AIO_WRITE:
        io_prep_pwritev(iocbs, fd, qiov->iov, qiov->niov, offset);
	break;
    case QEMU_AIO_READ:
        io_prep_preadv(iocbs, fd, qiov->iov, qiov->niov, offset);
	break;
    /* Currently Linux kernel does not support other operations */
    default:
        fprintf(stderr, "%s: invalid AIO request type 0x%x.\n",
                        __func__, type);
        goto out_free_aiocb;
    }
    io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e));

    if (!s->io_q.plugged) {
        if (io_submit(s->ctx, 1, &iocbs) < 0) {
            goto out_free_aiocb;
        }
    } else {
        ioq_enqueue(s, iocbs);
    }
    return &laiocb->common;

out_free_aiocb:
    qemu_aio_unref(laiocb);
    return NULL;
}