Re: [Qemu-devel] [PULL 08/11] iscsi: add .bdrv_get_block_status

[Stefan Weil <sw@weilnetz.de>]

Am 12.09.2013 13:17, schrieb Paolo Bonzini:
> From: Peter Lieven <pl@kamp.de>
>
> this patch adds a coroutine for .bdrv_co_block_status as well as
> a generic framework that can be used to build coroutines in block/iscsi.
>
> Signed-off-by: Peter Lieven <pl@kamp.de>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  block/iscsi.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 136 insertions(+)
>
> diff --git a/block/iscsi.c b/block/iscsi.c
> index bfd659a..c377d21 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -58,6 +58,15 @@ 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;
> @@ -111,6 +120,41 @@ 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,
> @@ -848,6 +892,96 @@ iscsi_getlength(BlockDriverState *bs)
>      return len;
>  }
>  
> +static int64_t coroutine_fn iscsi_co_get_block_status(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;
> +    int64_t ret;
> +
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +
> +    if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
> +        ret = -EINVAL;
> +        goto out;
> +    }
> +
> +    /* default to all sectors allocated */
> +    ret = BDRV_BLOCK_DATA;
> +    ret |= (sector_num << BDRV_SECTOR_BITS) | BDRV_BLOCK_OFFSET_VALID;
> +    *pnum = nb_sectors;
> +
> +    /* LUN does not support logical block provisioning */
> +    if (iscsilun->lbpme == 0) {
> +        goto out;
> +    }
> +
> +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 = -EIO;
> +        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 = -EIO;
> +        goto out;
> +    }
> +
> +    lbasd = &lbas->descriptors[0];
> +
> +    if (sector_qemu2lun(sector_num, iscsilun) != lbasd->lba) {
> +        ret = -EIO;
> +        goto out;
> +    }
> +
> +    *pnum = sector_lun2qemu(lbasd->num_blocks, iscsilun);
> +    if (*pnum > nb_sectors) {
> +        *pnum = nb_sectors;
> +    }
> +
> +    if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
> +        lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
> +        ret &= ~BDRV_BLOCK_DATA;
> +        if (iscsilun->lbprz) {
> +            ret |= BDRV_BLOCK_ZERO;
> +        }
> +    }
> +
> +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;
> @@ -1398,6 +1532,8 @@ static BlockDriver bdrv_iscsi = {
>      .bdrv_getlength  = iscsi_getlength,
>      .bdrv_truncate   = iscsi_truncate,
>  
> +    .bdrv_co_get_block_status = iscsi_co_get_block_status,
> +
>      .bdrv_aio_readv  = iscsi_aio_readv,
>      .bdrv_aio_writev = iscsi_aio_writev,
>      .bdrv_aio_flush  = iscsi_aio_flush,


Latest QEMU git is broken on Debian wheezy:

block/iscsi.c: In function ‘iscsi_co_get_block_status’:
block/iscsi.c:842:5: error: implicit declaration of function
‘iscsi_get_lba_status_task’ [-Werror=implicit-function-declaration]
block/iscsi.c:842:5: error: nested extern declaration of
‘iscsi_get_lba_status_task’ [-Werror=nested-externs]
block/iscsi.c:845:43: error: comparison between pointer and integer
[-Werror]
block/iscsi.c:877:18: error: dereferencing pointer to incomplete type
block/iscsi.c:879:55: error: dereferencing pointer to incomplete type
block/iscsi.c:884:34: error: dereferencing pointer to incomplete type
block/iscsi.c:889:14: error: dereferencing pointer to incomplete type
block/iscsi.c:889:32: error: ‘SCSI_PROVISIONING_TYPE_DEALLOCATED’
undeclared (first use in this function)
block/iscsi.c:889:32: note: each undeclared identifier is reported only
once for each function it appears in
block/iscsi.c:890:14: error: dereferencing pointer to incomplete type
block/iscsi.c:890:32: error: ‘SCSI_PROVISIONING_TYPE_ANCHORED’
undeclared (first use in this function)
cc1: all warnings being treated as errors

Debian includes libiscsi-dev 1.4.0 without a libiscsi.pk, so it uses a
compile test
which thinks that libiscsi is good enough.

Did the latest changes raise the requirements for libscsi?

Regards,
Stefan