Commit cb1b83e7 authored by Peter Lieven's avatar Peter Lieven Committed by Paolo Bonzini
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iscsi: add iscsi_truncate support 



this patch adds iscsi_truncate which effectively allows for
online resizing of iscsi volumes. for this to work you have
to resize the volume on your storage and then call
block_resize command in qemu which will issue a
readcapacity16 to update the capacity.

v4:
  - factor out complete readcapacity logic into a separate function
  - handle capacity change check condition in readcapacity function
    (this happens if the block_resize cmd is the first iscsi task
    executed after a resize on the storage)

v3:
  - remove switch statement in iscsi_open
  - create separate patch for brdv_drain_all() in bdrv_truncate()

v2:
  - add a general bdrv_drain_all() before bdrv_truncate() to avoid
    in-flight AIOs while the device is truncated
  - since no AIOs are in flight we can use a sync libiscsi call
    to re-read the capacity
  - factor out the readcapacity16 logic as it is redundant
    to iscsi_open() and iscsi_truncate().

Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
[allow any type of unit attention check condition in iscsi_readcapacity_sync(),
 as in Message-ID: <51263A2A.6070304@dlhnet.de> - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1dde716e

block/iscsi.c

+88 −47
Original line number Diff line number Diff line
@@ -938,6 +938,71 @@ static void iscsi_nop_timed_event(void *opaque) 
}

#endif



static int iscsi_readcapacity_sync(IscsiLun *iscsilun)

{

    struct scsi_task *task = NULL;

    struct scsi_readcapacity10 *rc10 = NULL;

    struct scsi_readcapacity16 *rc16 = NULL;

    int ret = 0;

    int retries = ISCSI_CMD_RETRIES; 



try_again:

    switch (iscsilun->type) {

    case TYPE_DISK:

        task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);

        if (task == NULL || task->status != SCSI_STATUS_GOOD) {

            if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION

                    && task->sense.key == SCSI_SENSE_UNIT_ATTENTION

                    && retries-- > 0) {

                scsi_free_scsi_task(task);

                goto try_again;

            }

            error_report("iSCSI: failed to send readcapacity16 command.");

            ret = -EINVAL;

            goto out;

        }

        rc16 = scsi_datain_unmarshall(task);

        if (rc16 == NULL) {

            error_report("iSCSI: Failed to unmarshall readcapacity16 data.");

            ret = -EINVAL;

            goto out;

        }

        iscsilun->block_size = rc16->block_length;

        iscsilun->num_blocks = rc16->returned_lba + 1;

        break;

    case TYPE_ROM:

        task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);

        if (task == NULL || task->status != SCSI_STATUS_GOOD) {

            error_report("iSCSI: failed to send readcapacity10 command.");

            ret = -EINVAL;

            goto out;

        }

        rc10 = scsi_datain_unmarshall(task);

        if (rc10 == NULL) {

            error_report("iSCSI: Failed to unmarshall readcapacity10 data.");

            ret = -EINVAL;

            goto out;

        }

        iscsilun->block_size = rc10->block_size;

        if (rc10->lba == 0) {

            /* blank disk loaded */

            iscsilun->num_blocks = 0;

        } else {

            iscsilun->num_blocks = rc10->lba + 1;

        }

        break;

    default:

        break;

    }



out:

    if (task) {

        scsi_free_scsi_task(task);

    }



    return ret;

}



/*

 * We support iscsi url's on the form

 * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
@@ -949,8 +1014,6 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) 
    struct iscsi_url *iscsi_url = NULL;

    struct scsi_task *task = NULL;

    struct scsi_inquiry_standard *inq = NULL;

    struct scsi_readcapacity10 *rc10 = NULL;

    struct scsi_readcapacity16 *rc16 = NULL;

    char *initiator_name = NULL;

    int ret;
@@ -1040,50 +1103,9 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) 


    iscsilun->type = inq->periperal_device_type;



    scsi_free_scsi_task(task);



    switch (iscsilun->type) {

    case TYPE_DISK:

        task = iscsi_readcapacity16_sync(iscsi, iscsilun->lun);

        if (task == NULL || task->status != SCSI_STATUS_GOOD) {

            error_report("iSCSI: failed to send readcapacity16 command.");

            ret = -EINVAL;

    if ((ret = iscsi_readcapacity_sync(iscsilun)) != 0) {

        goto out;

    }

        rc16 = scsi_datain_unmarshall(task);

        if (rc16 == NULL) {

            error_report("iSCSI: Failed to unmarshall readcapacity16 data.");

            ret = -EINVAL;

            goto out;

        }

        iscsilun->block_size = rc16->block_length;

        iscsilun->num_blocks = rc16->returned_lba + 1;

        break;

    case TYPE_ROM:

        task = iscsi_readcapacity10_sync(iscsi, iscsilun->lun, 0, 0);

        if (task == NULL || task->status != SCSI_STATUS_GOOD) {

            error_report("iSCSI: failed to send readcapacity10 command.");

            ret = -EINVAL;

            goto out;

        }

        rc10 = scsi_datain_unmarshall(task);

        if (rc10 == NULL) {

            error_report("iSCSI: Failed to unmarshall readcapacity10 data.");

            ret = -EINVAL;

            goto out;

        }

        iscsilun->block_size = rc10->block_size;

        if (rc10->lba == 0) {

            /* blank disk loaded */

            iscsilun->num_blocks = 0;

        } else {

            iscsilun->num_blocks = rc10->lba + 1;

        }

        break;

    default:

        break;

    }



    bs->total_sectors    = iscsilun->num_blocks *

                           iscsilun->block_size / BDRV_SECTOR_SIZE ;
@@ -1096,8 +1118,6 @@ static int iscsi_open(BlockDriverState *bs, const char *filename, int flags) 
        bs->sg = 1;

    }



    ret = 0;



#if defined(LIBISCSI_FEATURE_NOP_COUNTER)

    /* Set up a timer for sending out iSCSI NOPs */

    iscsilun->nop_timer = qemu_new_timer_ms(rt_clock, iscsi_nop_timed_event, iscsilun);
@@ -1138,6 +1158,26 @@ static void iscsi_close(BlockDriverState *bs) 
    memset(iscsilun, 0, sizeof(IscsiLun));

}



static int iscsi_truncate(BlockDriverState *bs, int64_t offset)

{

    IscsiLun *iscsilun = bs->opaque;

    int ret = 0;



    if (iscsilun->type != TYPE_DISK) {

        return -ENOTSUP;

    }



    if ((ret = iscsi_readcapacity_sync(iscsilun)) != 0) {

        return ret;

    }



    if (offset > iscsi_getlength(bs)) {

        return -EINVAL;

    }



    return 0;

}



static int iscsi_has_zero_init(BlockDriverState *bs)

{

    return 0;
@@ -1208,6 +1248,7 @@ static BlockDriver bdrv_iscsi = { 
    .create_options  = iscsi_create_options,



    .bdrv_getlength  = iscsi_getlength,

    .bdrv_truncate   = iscsi_truncate,



    .bdrv_aio_readv  = iscsi_aio_readv,

    .bdrv_aio_writev = iscsi_aio_writev,