Re: [Qemu-devel] [PATCHv5 3/3] iscsi: add .bdrv_co_discard

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/07/2013 09:19, Peter Lieven ha scritto:
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  block/iscsi.c |  156 +++++++++++++++++++++++++++------------------------------
>  1 file changed, 73 insertions(+), 83 deletions(-)
> 
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 19afd6c..cb44fb1 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -85,6 +85,7 @@ typedef struct IscsiAIOCB {
>  #define NOP_INTERVAL 5000
>  #define MAX_NOP_FAILURES 3
>  #define ISCSI_CMD_RETRIES 5
> +#define ISCSI_MAX_UNMAP 131072
>  
>  static void
>  iscsi_bh_cb(void *p)
> @@ -622,88 +623,6 @@ iscsi_aio_flush(BlockDriverState *bs,
>      return &acb->common;
>  }
>  
> -static int iscsi_aio_discard_acb(IscsiAIOCB *acb);
> -
> -static void
> -iscsi_unmap_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) {
> -            scsi_free_scsi_task(acb->task);
> -            acb->task = NULL;
> -            if (iscsi_aio_discard_acb(acb) == 0) {
> -                iscsi_set_events(acb->iscsilun);
> -                return;
> -            }
> -        }
> -        error_report("Failed to unmap data on iSCSI lun. %s",
> -                     iscsi_get_error(iscsi));
> -        acb->status = -EIO;
> -    }
> -
> -    iscsi_schedule_bh(acb);
> -}
> -
> -static int iscsi_aio_discard_acb(IscsiAIOCB *acb) {
> -    struct iscsi_context *iscsi = acb->iscsilun->iscsi;
> -    struct unmap_list list[1];
> -
> -    acb->canceled   = 0;
> -    acb->bh         = NULL;
> -    acb->status     = -EINPROGRESS;
> -    acb->buf        = NULL;
> -
> -    list[0].lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);
> -    list[0].num = acb->nb_sectors * BDRV_SECTOR_SIZE / acb->iscsilun->block_size;
> -
> -    acb->task = iscsi_unmap_task(iscsi, acb->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));
> -        return -1;
> -    }
> -
> -    return 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) {
> -        qemu_aio_release(acb);
> -        return NULL;
> -    }
> -
> -    iscsi_set_events(iscsilun);
> -
> -    return &acb->common;
> -}
> -
>  #ifdef __linux__
>  static void
>  iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
> @@ -985,6 +904,77 @@ out:
>      return ret;
>  }
>  
> +static int
> +coroutine_fn iscsi_co_discard(BlockDriverState *bs, int64_t sector_num,
> +                                   int nb_sectors)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct unmap_list list;
> +    uint32_t nb_blocks;
> +    uint32_t max_unmap;
> +
> +    if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
> +        return -EINVAL;
> +    }
> +
> +    if (!iscsilun->lbp.lbpu) {
> +        /* UNMAP is not supported by the target */
> +        return 0;
> +    }

I guess you'll later add support for lbpws.

Anyway, series looks fine.

Paolo

> +    list.lba = sector_qemu2lun(sector_num, iscsilun);
> +    nb_blocks = sector_qemu2lun(nb_sectors, iscsilun);
> +
> +    max_unmap = iscsilun->bl.max_unmap;
> +    if (max_unmap == 0xffffffff) {
> +        max_unmap = ISCSI_MAX_UNMAP;
> +    }
> +
> +    while (nb_blocks > 0) {
> +        iscsi_co_init_iscsitask(iscsilun, &iTask);
> +        list.num = nb_blocks;
> +        if (list.num > max_unmap) {
> +            list.num = max_unmap;
> +        }
> +retry:
> +        if (iscsi_unmap_task(iscsilun->iscsi, iscsilun->lun, 0, 0, &list, 1,
> +                         iscsi_co_generic_cb, &iTask) == NULL) {
> +            return -EIO;
> +        }
> +
> +        while (!iTask.complete) {
> +            iscsi_set_events(iscsilun);
> +            qemu_coroutine_yield();
> +        }
> +
> +        if (iTask.task != NULL) {
> +            scsi_free_scsi_task(iTask.task);
> +            iTask.task = NULL;
> +        }
> +
> +        if (iTask.do_retry) {
> +            goto retry;
> +        }
> +
> +        if (iTask.status == SCSI_STATUS_CHECK_CONDITION) {
> +            /* the target might fail with a check condition if it
> +               is not happy with the alignment of the UNMAP request
> +               we silently fail in this case */
> +            return 0;
> +        }
> +
> +        if (iTask.status != SCSI_STATUS_GOOD) {
> +            return -EIO;
> +        }
> +
> +        list.lba += list.num;
> +        nb_blocks -= list.num;
> +    }
> +
> +    return 0;
> +}
> +
>  static int parse_chap(struct iscsi_context *iscsi, const char *target)
>  {
>      QemuOptsList *list;
> @@ -1527,12 +1517,12 @@ static BlockDriver bdrv_iscsi = {
>      .bdrv_truncate   = iscsi_truncate,
>  
>      .bdrv_co_get_block_status = iscsi_co_get_block_status,
> +    .bdrv_co_discard      = iscsi_co_discard,
>  
>      .bdrv_aio_readv  = iscsi_aio_readv,
>      .bdrv_aio_writev = iscsi_aio_writev,
>      .bdrv_aio_flush  = iscsi_aio_flush,
>  
> -    .bdrv_aio_discard = iscsi_aio_discard,
>      .bdrv_has_zero_init = iscsi_has_zero_init,
>  
>  #ifdef __linux__
>