Esempio n. 1
0
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;
}
Esempio n. 2
0
File: iscsi.c Progetto: chonghw/pemu
static void
iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status,
                     void *command_data, void *opaque)
{
    IscsiAIOCB *acb = opaque;

    trace_iscsi_aio_write16_cb(iscsi, status, acb, acb->canceled);

    g_free(acb->buf);
    acb->buf = NULL;

    if (acb->canceled != 0) {
        return;
    }

    acb->status = 0;
    if (status != 0) {
        if (status == SCSI_STATUS_CHECK_CONDITION
            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
            && acb->retries-- > 0) {
            scsi_free_scsi_task(acb->task);
            acb->task = NULL;
            if (iscsi_aio_writev_acb(acb) == 0) {
                iscsi_set_events(acb->iscsilun);
                return;
            }
        }
        error_report("Failed to write16 data to iSCSI lun. %s",
                     iscsi_get_error(iscsi));
        acb->status = -EIO;
    }

    iscsi_schedule_bh(acb);
}
Esempio n. 3
0
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;
}
Esempio n. 4
0
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_aiocb_info, bs, cb, opaque);

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

    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;
}
Esempio n. 5
0
File: iscsi.c Progetto: 3a9LL/panda
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;
}
Esempio n. 6
0
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;
}
Esempio n. 7
0
static void
iscsi_synccache10_cb(struct iscsi_context *iscsi, int status,
                     void *command_data, void *opaque)
{
    IscsiAIOCB *acb = opaque;

    if (acb->canceled != 0) {
        return;
    }

    acb->status = 0;
    if (status != 0) {
        if (status == SCSI_STATUS_CHECK_CONDITION
            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
            && acb->retries-- > 0) {
            if (acb->task != NULL) {
                scsi_free_scsi_task(acb->task);
                acb->task = NULL;
            }
            if (iscsi_aio_flush_acb(acb) == 0) {
                iscsi_set_events(acb->iscsilun);
                return;
            }
        }
        error_report("Failed to sync10 data on iSCSI lun. %s",
                     iscsi_get_error(iscsi));
        acb->status = -EIO;
    }

    iscsi_schedule_bh(acb);
}
Esempio n. 8
0
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;
}
Esempio n. 9
0
static void
iscsi_process_write(void *arg)
{
    IscsiLun *iscsilun = arg;
    struct iscsi_context *iscsi = iscsilun->iscsi;

    iscsi_service(iscsi, POLLOUT);
    iscsi_set_events(iscsilun);
}
Esempio n. 10
0
File: iscsi.c Progetto: 3a9LL/panda
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;
}
Esempio n. 11
0
static void iscsi_nop_timed_event(void *opaque)
{
    IscsiLun *iscsilun = opaque;

    if (iscsi_get_nops_in_flight(iscsilun->iscsi) > MAX_NOP_FAILURES) {
        error_report("iSCSI: NOP timeout. Reconnecting...");
        iscsi_reconnect(iscsilun->iscsi);
    }

    if (iscsi_nop_out_async(iscsilun->iscsi, NULL, NULL, 0, NULL) != 0) {
        error_report("iSCSI: failed to sent NOP-Out. Disabling NOP messages.");
        return;
    }

    qemu_mod_timer(iscsilun->nop_timer, qemu_get_clock_ms(rt_clock) + NOP_INTERVAL);
    iscsi_set_events(iscsilun);
}
Esempio n. 12
0
static BlockDriverAIOCB *
iscsi_aio_flush(BlockDriverState *bs,
                BlockDriverCompletionFunc *cb, void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;

    IscsiAIOCB *acb;

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

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

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

    iscsi_set_events(iscsilun);

    return &acb->common;
}
Esempio n. 13
0
static BlockDriverAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
        unsigned long int req, void *buf,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = iscsilun->iscsi;
    struct iscsi_data data;
    IscsiAIOCB *acb;

    assert(req == SG_IO);

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

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

    acb->task = malloc(sizeof(struct scsi_task));
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to allocate task for scsi command. %s",
                     iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }
    memset(acb->task, 0, sizeof(struct scsi_task));

    switch (acb->ioh->dxfer_direction) {
    case SG_DXFER_TO_DEV:
        acb->task->xfer_dir = SCSI_XFER_WRITE;
        break;
    case SG_DXFER_FROM_DEV:
        acb->task->xfer_dir = SCSI_XFER_READ;
        break;
    default:
        acb->task->xfer_dir = SCSI_XFER_NONE;
        break;
    }

    acb->task->cdb_size = acb->ioh->cmd_len;
    memcpy(&acb->task->cdb[0], acb->ioh->cmdp, acb->ioh->cmd_len);
    acb->task->expxferlen = acb->ioh->dxfer_len;

    data.size = 0;
    if (acb->task->xfer_dir == SCSI_XFER_WRITE) {
        if (acb->ioh->iovec_count == 0) {
            data.data = acb->ioh->dxferp;
            data.size = acb->ioh->dxfer_len;
        } else {
#if defined(LIBISCSI_FEATURE_IOVECTOR)
            scsi_task_set_iov_out(acb->task,
                                 (struct scsi_iovec *) acb->ioh->dxferp,
                                 acb->ioh->iovec_count);
#else
            struct iovec *iov = (struct iovec *)acb->ioh->dxferp;

            acb->buf = g_malloc(acb->ioh->dxfer_len);
            data.data = acb->buf;
            data.size = iov_to_buf(iov, acb->ioh->iovec_count, 0,
                                   acb->buf, acb->ioh->dxfer_len);
#endif
        }
    }

    if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
                                 iscsi_aio_ioctl_cb,
                                 (data.size > 0) ? &data : NULL,
                                 acb) != 0) {
        scsi_free_scsi_task(acb->task);
        qemu_aio_release(acb);
        return NULL;
    }

    /* tell libiscsi to read straight into the buffer we got from ioctl */
    if (acb->task->xfer_dir == SCSI_XFER_READ) {
        if (acb->ioh->iovec_count == 0) {
            scsi_task_add_data_in_buffer(acb->task,
                                         acb->ioh->dxfer_len,
                                         acb->ioh->dxferp);
        } else {
#if defined(LIBISCSI_FEATURE_IOVECTOR)
            scsi_task_set_iov_in(acb->task,
                                 (struct scsi_iovec *) acb->ioh->dxferp,
                                 acb->ioh->iovec_count);
#else
            int i;
            for (i = 0; i < acb->ioh->iovec_count; i++) {
                struct iovec *iov = (struct iovec *)acb->ioh->dxferp;

                scsi_task_add_data_in_buffer(acb->task,
                    iov[i].iov_len,
                    iov[i].iov_base);
            }
#endif
        }
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}
Esempio n. 14
0
File: iscsi.c Progetto: breuerr/qemu
/*
 * We support iscsi url's on the form
 * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
 */
static int iscsi_open(BlockDriverState *bs, const char *filename, int flags)
{
    IscsiLun *iscsilun = bs->opaque;
    struct iscsi_context *iscsi = NULL;
    struct iscsi_url *iscsi_url = NULL;
    struct IscsiTask task;
    char *initiator_name = NULL;
    int ret;

    if ((BDRV_SECTOR_SIZE % 512) != 0) {
        error_report("iSCSI: Invalid BDRV_SECTOR_SIZE. "
                     "BDRV_SECTOR_SIZE(%lld) is not a multiple "
                     "of 512", BDRV_SECTOR_SIZE);
        return -EINVAL;
    }

    iscsi_url = iscsi_parse_full_url(iscsi, filename);
    if (iscsi_url == NULL) {
        error_report("Failed to parse URL : %s %s", filename,
                     iscsi_get_error(iscsi));
        ret = -EINVAL;
        goto failed;
    }

    memset(iscsilun, 0, sizeof(IscsiLun));

    initiator_name = parse_initiator_name(iscsi_url->target);

    iscsi = iscsi_create_context(initiator_name);
    if (iscsi == NULL) {
        error_report("iSCSI: Failed to create iSCSI context.");
        ret = -ENOMEM;
        goto failed;
    }

    if (iscsi_set_targetname(iscsi, iscsi_url->target)) {
        error_report("iSCSI: Failed to set target name.");
        ret = -EINVAL;
        goto failed;
    }

    if (iscsi_url->user != NULL) {
        ret = iscsi_set_initiator_username_pwd(iscsi, iscsi_url->user,
                                              iscsi_url->passwd);
        if (ret != 0) {
            error_report("Failed to set initiator username and password");
            ret = -EINVAL;
            goto failed;
        }
    }

    /* check if we got CHAP username/password via the options */
    if (parse_chap(iscsi, iscsi_url->target) != 0) {
        error_report("iSCSI: Failed to set CHAP user/password");
        ret = -EINVAL;
        goto failed;
    }

    if (iscsi_set_session_type(iscsi, ISCSI_SESSION_NORMAL) != 0) {
        error_report("iSCSI: Failed to set session type to normal.");
        ret = -EINVAL;
        goto failed;
    }

    iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE_CRC32C);

    /* check if we got HEADER_DIGEST via the options */
    parse_header_digest(iscsi, iscsi_url->target);

    task.iscsilun = iscsilun;
    task.status = 0;
    task.complete = 0;
    task.bs = bs;

    iscsilun->iscsi = iscsi;
    iscsilun->lun   = iscsi_url->lun;

    if (iscsi_full_connect_async(iscsi, iscsi_url->portal, iscsi_url->lun,
                                 iscsi_connect_cb, &task)
        != 0) {
        error_report("iSCSI: Failed to start async connect.");
        ret = -EINVAL;
        goto failed;
    }

    while (!task.complete) {
        iscsi_set_events(iscsilun);
        qemu_aio_wait();
    }
    if (task.status != 0) {
        error_report("iSCSI: Failed to connect to LUN : %s",
                     iscsi_get_error(iscsi));
        ret = -EINVAL;
        goto failed;
    }

    if (iscsi_url != NULL) {
        iscsi_destroy_url(iscsi_url);
    }
    return 0;

failed:
    if (initiator_name != NULL) {
        g_free(initiator_name);
    }
    if (iscsi_url != NULL) {
        iscsi_destroy_url(iscsi_url);
    }
    if (iscsi != NULL) {
        iscsi_destroy_context(iscsi);
    }
    memset(iscsilun, 0, sizeof(IscsiLun));
    return ret;
}
Esempio n. 15
0
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;
    int i;
    uint64_t lba;
    uint32_t num_sectors;

    qemu_read_size = BDRV_SECTOR_SIZE * (size_t)nb_sectors;

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

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

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

    num_sectors  = (qemu_read_size + iscsilun->block_size
                    + acb->read_offset - 1)
                    / iscsilun->block_size;

    acb->task = malloc(sizeof(struct scsi_task));
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to allocate task for scsi READ16 "
                     "command. %s", iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }
    memset(acb->task, 0, sizeof(struct scsi_task));

    acb->task->xfer_dir = SCSI_XFER_READ;
    lba = sector_qemu2lun(sector_num, iscsilun);
    acb->task->expxferlen = qemu_read_size;

    switch (iscsilun->type) {
    case TYPE_DISK:
        acb->task->cdb_size = 16;
        acb->task->cdb[0]  = 0x88;
        *(uint32_t *)&acb->task->cdb[2]  = htonl(lba >> 32);
        *(uint32_t *)&acb->task->cdb[6]  = htonl(lba & 0xffffffff);
        *(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);
        break;
    default:
        acb->task->cdb_size = 10;
        acb->task->cdb[0]  = 0x28;
        *(uint32_t *)&acb->task->cdb[2] = htonl(lba);
        *(uint16_t *)&acb->task->cdb[7] = htons(num_sectors);
        break;
    }

    if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
                                 iscsi_aio_read16_cb,
                                 NULL,
                                 acb) != 0) {
        scsi_free_scsi_task(acb->task);
        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;
}
Esempio n. 16
0
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;
    uint32_t num_sectors;
    uint64_t lba;
    struct iscsi_data data;

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

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

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

    /* XXX we should pass the iovec to write16 to avoid the extra copy */
    /* this will allow us to get rid of 'buf' completely */
    size = nb_sectors * BDRV_SECTOR_SIZE;
    data.size = MIN(size, acb->qiov->size);

    /* if the iovec only contains one buffer we can pass it directly */
    if (acb->qiov->niov == 1) {
        acb->buf = NULL;
        data.data = acb->qiov->iov[0].iov_base;
    } else {
        acb->buf = g_malloc(data.size);
        qemu_iovec_to_buf(acb->qiov, 0, acb->buf, data.size);
        data.data = acb->buf;
    }

    acb->task = malloc(sizeof(struct scsi_task));
    if (acb->task == NULL) {
        error_report("iSCSI: Failed to allocate task for scsi WRITE16 "
                     "command. %s", iscsi_get_error(iscsi));
        qemu_aio_release(acb);
        return NULL;
    }
    memset(acb->task, 0, sizeof(struct scsi_task));

    acb->task->xfer_dir = SCSI_XFER_WRITE;
    acb->task->cdb_size = 16;
    acb->task->cdb[0] = 0x8a;
    lba = sector_qemu2lun(sector_num, iscsilun);
    *(uint32_t *)&acb->task->cdb[2]  = htonl(lba >> 32);
    *(uint32_t *)&acb->task->cdb[6]  = htonl(lba & 0xffffffff);
    num_sectors = size / iscsilun->block_size;
    *(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);
    acb->task->expxferlen = size;

    if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
                                 iscsi_aio_write16_cb,
                                 &data,
                                 acb) != 0) {
        scsi_free_scsi_task(acb->task);
        g_free(acb->buf);
        qemu_aio_release(acb);
        return NULL;
    }

    iscsi_set_events(iscsilun);

    return &acb->common;
}