Re: [Qemu-devel] [PATCHv4 2/2] iscsi: add .bdrv_co_is_allocated

[Paolo Bonzini <pbonzini@redhat.com>]

Il 18/07/2013 10:19, Peter Lieven ha scritto:
> this patch adds a coroutine for .bdrv_co_is_allocated as well as
> a generic framework that can be used to build coroutines in block/iscsi.

This conflicts with my bdrv_get_block_status patches.

Paolo

> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  block/iscsi.c |  130 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 130 insertions(+)
> 
> diff --git a/block/iscsi.c b/block/iscsi.c
> index ab42f1e..56dedff 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -55,6 +55,15 @@ typedef struct IscsiLun {
>      struct scsi_inquiry_block_limits bl;
>  } IscsiLun;
>  
> +typedef struct IscsiTask {
> +    int status;
> +    int complete;
> +    int retries;
> +    int do_retry;
> +    struct scsi_task *task;
> +    Coroutine *co;
> +} IscsiTask;
> +
>  typedef struct IscsiAIOCB {
>      BlockDriverAIOCB common;
>      QEMUIOVector *qiov;
> @@ -110,6 +119,41 @@ iscsi_schedule_bh(IscsiAIOCB *acb)
>      qemu_bh_schedule(acb->bh);
>  }
>  
> +static void
> +iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
> +                        void *command_data, void *opaque)
> +{
> +    struct IscsiTask *iTask = opaque;
> +    struct scsi_task *task = command_data;
> +
> +    iTask->complete = 1;
> +    iTask->status = status;
> +    iTask->do_retry = 0;
> +    iTask->task = task;
> +
> +    if (iTask->retries-- > 0 && status == SCSI_STATUS_CHECK_CONDITION
> +        && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) {
> +        iTask->do_retry = 1;
> +        goto out;
> +    }
> +
> +    if (status != SCSI_STATUS_GOOD) {
> +        error_report("iSCSI: Failure. %s", iscsi_get_error(iscsi));
> +    }
> +
> +out:
> +    if (iTask->co) {
> +        qemu_coroutine_enter(iTask->co, NULL);
> +    }
> +}
> +
> +static void iscsi_co_init_iscsitask(IscsiLun *iscsilun, struct IscsiTask *iTask)
> +{
> +    *iTask = (struct IscsiTask) {
> +        .co         = qemu_coroutine_self(),
> +        .retries    = ISCSI_CMD_RETRIES,
> +    };
> +}
>  
>  static void
>  iscsi_abort_task_cb(struct iscsi_context *iscsi, int status, void *command_data,
> @@ -804,6 +848,90 @@ iscsi_getlength(BlockDriverState *bs)
>      return len;
>  }
>  
> +static int coroutine_fn iscsi_co_is_allocated(BlockDriverState *bs,
> +                                              int64_t sector_num,
> +                                              int nb_sectors, int *pnum)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct scsi_get_lba_status *lbas = NULL;
> +    struct scsi_lba_status_descriptor *lbasd = NULL;
> +    struct IscsiTask iTask;
> +    int ret;
> +
> +    /* default to all sectors allocated */
> +    ret = 1;
> +    *pnum = nb_sectors;
> +
> +    /* LUN does not support logical block provisioning */
> +    if (iscsilun->lbpme == 0) {
> +        goto out;
> +    }
> +
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +
> +retry:
> +    if (iscsi_get_lba_status_task(iscsilun->iscsi, iscsilun->lun,
> +                                  sector_qemu2lun(sector_num, iscsilun),
> +                                  8 + 16, iscsi_co_generic_cb,
> +                                  &iTask) == NULL) {
> +        ret = 0;
> +        *pnum = 0;
> +        goto out;
> +    }
> +
> +    while (!iTask.complete) {
> +        iscsi_set_events(iscsilun);
> +        qemu_coroutine_yield();
> +    }
> +
> +    if (iTask.do_retry) {
> +        if (iTask.task != NULL) {
> +            scsi_free_scsi_task(iTask.task);
> +            iTask.task = NULL;
> +        }
> +        goto retry;
> +    }
> +
> +    if (iTask.status != SCSI_STATUS_GOOD) {
> +        /* in case the get_lba_status_callout fails (i.e.
> +         * because the device is busy or the cmd is not
> +         * supported) we pretend all blocks are allocated
> +         * for backwards compatiblity */
> +        goto out;
> +    }
> +
> +    lbas = scsi_datain_unmarshall(iTask.task);
> +    if (lbas == NULL) {
> +        ret = 0;
> +        *pnum = 0;
> +        goto out;
> +    }
> +
> +    lbasd = &lbas->descriptors[0];
> +
> +    if (sector_qemu2lun(sector_num, iscsilun) != lbasd->lba) {
> +        ret = 0;
> +        *pnum = 0;
> +        goto out;
> +    }
> +
> +    *pnum = lbasd->num_blocks * (iscsilun->block_size / BDRV_SECTOR_SIZE);
> +    if (*pnum > nb_sectors) {
> +        *pnum = nb_sectors;
> +    }
> +
> +    if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
> +        lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
> +        ret = 0;
> +    }
> +
> +out:
> +    if (iTask.task != NULL) {
> +        scsi_free_scsi_task(iTask.task);
> +    }
> +    return ret;
> +}
> +
>  static int parse_chap(struct iscsi_context *iscsi, const char *target)
>  {
>      QemuOptsList *list;
> @@ -1345,6 +1473,8 @@ static BlockDriver bdrv_iscsi = {
>      .bdrv_getlength  = iscsi_getlength,
>      .bdrv_truncate   = iscsi_truncate,
>  
> +    .bdrv_co_is_allocated = iscsi_co_is_allocated,
> +
>      .bdrv_aio_readv  = iscsi_aio_readv,
>      .bdrv_aio_writev = iscsi_aio_writev,
>      .bdrv_aio_flush  = iscsi_aio_flush,
>