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

[Peter Lieven <pl@kamp.de>]

On 19.07.2013 11:18, Paolo Bonzini wrote:
> 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.
It depends: I think almost all targets will support both. I would use unmap for discard and write_same for write_zeroes.

Peter
>
> Anyway, series looks fine.
Thanks. Feel free to pull it once the get_lba_status thing is upstream.

Peter