Commit 1dde716e authored by Peter Lieven's avatar Peter Lieven Committed by Paolo Bonzini
Browse files

iscsi: retry read, write, flush and unmap on unit attention check conditions 



the storage might return a check condition status for various reasons.
(e.g. bus reset, capacity change, thin-provisioning info etc.)

currently all these informative status responses lead to an I/O error
which is populated to the guest. this patch introduces a retry mechanism
to avoid this.

Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 76c48503

block/iscsi.c

+203 −88
Original line number Diff line number Diff line
@@ -60,8 +60,11 @@ typedef struct IscsiAIOCB { 
    uint8_t *buf;

    int status;

    int canceled;

    int retries;

    size_t read_size;

    size_t read_offset;

    int64_t sector_num;

    int nb_sectors;

#ifdef __linux__

    sg_io_hdr_t *ioh;

#endif
@@ -69,6 +72,7 @@ typedef struct IscsiAIOCB { 


#define NOP_INTERVAL 5000

#define MAX_NOP_FAILURES 3

#define ISCSI_CMD_RETRIES 5



static void

iscsi_bh_cb(void *p)
@@ -191,6 +195,8 @@ iscsi_process_write(void *arg) 
    iscsi_set_events(iscsilun);

}



static int

iscsi_aio_writev_acb(IscsiAIOCB *acb);



static void

iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status,
@@ -208,7 +214,19 @@ iscsi_aio_write16_cb(struct iscsi_context *iscsi, int status, 
    }



    acb->status = 0;

    if (status < 0) {

    if (status != 0) {

        if (status == SCSI_STATUS_CHECK_CONDITION

            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION

            && acb->retries-- > 0) {

            if (acb->task != NULL) {

                scsi_free_scsi_task(acb->task);

                acb->task = NULL;

            }

            if (iscsi_aio_writev_acb(acb) == 0) {

                iscsi_set_events(acb->iscsilun);

                return;

            }

        }

        error_report("Failed to write16 data to iSCSI lun. %s",

                     iscsi_get_error(iscsi));

        acb->status = -EIO;
@@ -222,15 +240,10 @@ static int64_t sector_qemu2lun(int64_t sector, IscsiLun *iscsilun) 
    return sector * BDRV_SECTOR_SIZE / iscsilun->block_size;

}



static BlockDriverAIOCB *

iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,

                 QEMUIOVector *qiov, int nb_sectors,

                 BlockDriverCompletionFunc *cb,

                 void *opaque)

static int

iscsi_aio_writev_acb(IscsiAIOCB *acb)

{

    IscsiLun *iscsilun = bs->opaque;

    struct iscsi_context *iscsi = iscsilun->iscsi;

    IscsiAIOCB *acb;

    struct iscsi_context *iscsi = acb->iscsilun->iscsi;

    size_t size;

    uint32_t num_sectors;

    uint64_t lba;
@@ -239,19 +252,13 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num, 
#endif

    int ret;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    trace_iscsi_aio_writev(iscsi, sector_num, nb_sectors, opaque, acb);



    acb->iscsilun = iscsilun;

    acb->qiov     = qiov;



    acb->canceled   = 0;

    acb->bh         = NULL;

    acb->status     = -EINPROGRESS;

    acb->buf        = NULL;



    /* this will allow us to get rid of 'buf' completely */

    size = nb_sectors * BDRV_SECTOR_SIZE;

    size = acb->nb_sectors * BDRV_SECTOR_SIZE;



#if !defined(LIBISCSI_FEATURE_IOVECTOR)

    data.size = MIN(size, acb->qiov->size);
@@ -270,48 +277,76 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num, 
    if (acb->task == NULL) {

        error_report("iSCSI: Failed to allocate task for scsi WRITE16 "

                     "command. %s", iscsi_get_error(iscsi));

        qemu_aio_release(acb);

        return NULL;

        return -1;

    }

    memset(acb->task, 0, sizeof(struct scsi_task));



    acb->task->xfer_dir = SCSI_XFER_WRITE;

    acb->task->cdb_size = 16;

    acb->task->cdb[0] = 0x8a;

    lba = sector_qemu2lun(sector_num, iscsilun);

    lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);

    *(uint32_t *)&acb->task->cdb[2]  = htonl(lba >> 32);

    *(uint32_t *)&acb->task->cdb[6]  = htonl(lba & 0xffffffff);

    num_sectors = size / iscsilun->block_size;

    num_sectors = size / acb->iscsilun->block_size;

    *(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);

    acb->task->expxferlen = size;



#if defined(LIBISCSI_FEATURE_IOVECTOR)

    ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,

    ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,

                                   iscsi_aio_write16_cb,

                                   NULL,

                                   acb);

#else

    ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,

    ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,

                                   iscsi_aio_write16_cb,

                                   &data,

                                   acb);

#endif

    if (ret != 0) {

        scsi_free_scsi_task(acb->task);

        g_free(acb->buf);

        qemu_aio_release(acb);

        return NULL;

        return -1;

    }



#if defined(LIBISCSI_FEATURE_IOVECTOR)

    scsi_task_set_iov_out(acb->task, (struct scsi_iovec*) acb->qiov->iov, acb->qiov->niov);

#endif



    iscsi_set_events(iscsilun);

    return 0;

}



static BlockDriverAIOCB *

iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,

                 QEMUIOVector *qiov, int nb_sectors,

                 BlockDriverCompletionFunc *cb,

                 void *opaque)

{

    IscsiLun *iscsilun = bs->opaque;

    IscsiAIOCB *acb;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    trace_iscsi_aio_writev(iscsilun->iscsi, sector_num, nb_sectors, opaque, acb);



    acb->iscsilun    = iscsilun;

    acb->qiov        = qiov;

    acb->nb_sectors  = nb_sectors;

    acb->sector_num  = sector_num;

    acb->retries     = ISCSI_CMD_RETRIES;



    if (iscsi_aio_writev_acb(acb) != 0) {

        if (acb->task) {

            scsi_free_scsi_task(acb->task);

        }

        qemu_aio_release(acb);

        return NULL;

    }



    iscsi_set_events(iscsilun);

    return &acb->common;

}



static int

iscsi_aio_readv_acb(IscsiAIOCB *acb);



static void

iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status,

                    void *command_data, void *opaque)
@@ -326,6 +361,18 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status, 


    acb->status = 0;

    if (status != 0) {

        if (status == SCSI_STATUS_CHECK_CONDITION

            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION

            && acb->retries-- > 0) {

            if (acb->task != NULL) {

                scsi_free_scsi_task(acb->task);

                acb->task = NULL;

            }

            if (iscsi_aio_readv_acb(acb) == 0) {

                iscsi_set_events(acb->iscsilun);

                return;

            }

        }

        error_report("Failed to read16 data from iSCSI lun. %s",

                     iscsi_get_error(iscsi));

        acb->status = -EIO;
@@ -334,35 +381,20 @@ iscsi_aio_read16_cb(struct iscsi_context *iscsi, int status, 
    iscsi_schedule_bh(acb);

}



static BlockDriverAIOCB *

iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,

                QEMUIOVector *qiov, int nb_sectors,

                BlockDriverCompletionFunc *cb,

                void *opaque)

static int

iscsi_aio_readv_acb(IscsiAIOCB *acb)

{

    IscsiLun *iscsilun = bs->opaque;

    struct iscsi_context *iscsi = iscsilun->iscsi;

    IscsiAIOCB *acb;

    size_t qemu_read_size;

    struct iscsi_context *iscsi = acb->iscsilun->iscsi;

    uint64_t lba;

    uint32_t num_sectors;

    int ret;

#if !defined(LIBISCSI_FEATURE_IOVECTOR)

    int i;

#endif

    int ret;

    uint64_t lba;

    uint32_t num_sectors;



    qemu_read_size = BDRV_SECTOR_SIZE * (size_t)nb_sectors;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    trace_iscsi_aio_readv(iscsi, sector_num, nb_sectors, opaque, acb);



    acb->iscsilun = iscsilun;

    acb->qiov     = qiov;



    acb->canceled    = 0;

    acb->bh          = NULL;

    acb->status      = -EINPROGRESS;

    acb->read_size   = qemu_read_size;

    acb->buf         = NULL;



    /* If LUN blocksize is bigger than BDRV_BLOCK_SIZE a read from QEMU
@@ -370,30 +402,29 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num, 
     * data.

     */

    acb->read_offset = 0;

    if (iscsilun->block_size > BDRV_SECTOR_SIZE) {

        uint64_t bdrv_offset = BDRV_SECTOR_SIZE * sector_num;

    if (acb->iscsilun->block_size > BDRV_SECTOR_SIZE) {

        uint64_t bdrv_offset = BDRV_SECTOR_SIZE * acb->sector_num;



        acb->read_offset  = bdrv_offset % iscsilun->block_size;

        acb->read_offset  = bdrv_offset % acb->iscsilun->block_size;

    }



    num_sectors  = (qemu_read_size + iscsilun->block_size

    num_sectors  = (acb->read_size + acb->iscsilun->block_size

                    + acb->read_offset - 1)

                    / iscsilun->block_size;

                    / acb->iscsilun->block_size;



    acb->task = malloc(sizeof(struct scsi_task));

    if (acb->task == NULL) {

        error_report("iSCSI: Failed to allocate task for scsi READ16 "

                     "command. %s", iscsi_get_error(iscsi));

        qemu_aio_release(acb);

        return NULL;

        return -1;

    }

    memset(acb->task, 0, sizeof(struct scsi_task));



    acb->task->xfer_dir = SCSI_XFER_READ;

    lba = sector_qemu2lun(sector_num, iscsilun);

    acb->task->expxferlen = qemu_read_size;

    lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);

    acb->task->expxferlen = acb->read_size;



    switch (iscsilun->type) {

    switch (acb->iscsilun->type) {

    case TYPE_DISK:

        acb->task->cdb_size = 16;

        acb->task->cdb[0]  = 0x88;
@@ -409,14 +440,12 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num, 
        break;

    }



    ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,

    ret = iscsi_scsi_command_async(iscsi, acb->iscsilun->lun, acb->task,

                                   iscsi_aio_read16_cb,

                                   NULL,

                                   acb);

    if (ret != 0) {

        scsi_free_scsi_task(acb->task);

        qemu_aio_release(acb);

        return NULL;

        return -1;

    }



#if defined(LIBISCSI_FEATURE_IOVECTOR)
@@ -428,12 +457,42 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num, 
                acb->qiov->iov[i].iov_base);

    }

#endif

    return 0;

}



    iscsi_set_events(iscsilun);

static BlockDriverAIOCB *

iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,

                QEMUIOVector *qiov, int nb_sectors,

                BlockDriverCompletionFunc *cb,

                void *opaque)

{

    IscsiLun *iscsilun = bs->opaque;

    IscsiAIOCB *acb;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    trace_iscsi_aio_readv(iscsilun->iscsi, sector_num, nb_sectors, opaque, acb);



    acb->nb_sectors  = nb_sectors;

    acb->sector_num  = sector_num;

    acb->iscsilun    = iscsilun;

    acb->qiov        = qiov;

    acb->read_size   = BDRV_SECTOR_SIZE * (size_t)acb->nb_sectors;

    acb->retries     = ISCSI_CMD_RETRIES;



    if (iscsi_aio_readv_acb(acb) != 0) {

        if (acb->task) {

            scsi_free_scsi_task(acb->task);

        }

        qemu_aio_release(acb);

        return NULL;

    }



    iscsi_set_events(iscsilun);

    return &acb->common;

}



static int

iscsi_aio_flush_acb(IscsiAIOCB *acb);



static void

iscsi_synccache10_cb(struct iscsi_context *iscsi, int status,
@@ -446,7 +505,19 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int status, 
    }



    acb->status = 0;

    if (status < 0) {

    if (status != 0) {

        if (status == SCSI_STATUS_CHECK_CONDITION

            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION

            && acb->retries-- > 0) {

            if (acb->task != NULL) {

                scsi_free_scsi_task(acb->task);

                acb->task = NULL;

            }

            if (iscsi_aio_flush_acb(acb) == 0) {

                iscsi_set_events(acb->iscsilun);

                return;

            }

        }

        error_report("Failed to sync10 data on iSCSI lun. %s",

                     iscsi_get_error(iscsi));

        acb->status = -EIO;
@@ -455,29 +526,43 @@ iscsi_synccache10_cb(struct iscsi_context *iscsi, int status, 
    iscsi_schedule_bh(acb);

}



static BlockDriverAIOCB *

iscsi_aio_flush(BlockDriverState *bs,

                BlockDriverCompletionFunc *cb, void *opaque)

static int

iscsi_aio_flush_acb(IscsiAIOCB *acb)

{

    IscsiLun *iscsilun = bs->opaque;

    struct iscsi_context *iscsi = iscsilun->iscsi;

    IscsiAIOCB *acb;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);

    struct iscsi_context *iscsi = acb->iscsilun->iscsi;



    acb->iscsilun = iscsilun;

    acb->canceled   = 0;

    acb->bh         = NULL;

    acb->status     = -EINPROGRESS;

    acb->buf        = NULL;



    acb->task = iscsi_synchronizecache10_task(iscsi, iscsilun->lun,

    acb->task = iscsi_synchronizecache10_task(iscsi, acb->iscsilun->lun,

                                         0, 0, 0, 0,

                                         iscsi_synccache10_cb,

                                         acb);

    if (acb->task == NULL) {

        error_report("iSCSI: Failed to send synchronizecache10 command. %s",

                     iscsi_get_error(iscsi));

        return -1;

    }



    return 0;

}



static BlockDriverAIOCB *

iscsi_aio_flush(BlockDriverState *bs,

                BlockDriverCompletionFunc *cb, void *opaque)

{

    IscsiLun *iscsilun = bs->opaque;



    IscsiAIOCB *acb;



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);



    acb->iscsilun    = iscsilun;

    acb->retries     = ISCSI_CMD_RETRIES;



    if (iscsi_aio_flush_acb(acb) != 0) {

        qemu_aio_release(acb);

        return NULL;

    }
@@ -487,6 +572,8 @@ 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)
@@ -498,7 +585,19 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status, 
    }



    acb->status = 0;

    if (status < 0) {

    if (status != 0) {

        if (status == SCSI_STATUS_CHECK_CONDITION

            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION

            && acb->retries-- > 0) {

            if (acb->task != NULL) {

                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;
@@ -507,34 +606,50 @@ iscsi_unmap_cb(struct iscsi_context *iscsi, int status, 
    iscsi_schedule_bh(acb);

}



static BlockDriverAIOCB *

iscsi_aio_discard(BlockDriverState *bs,

                  int64_t sector_num, int nb_sectors,

                  BlockDriverCompletionFunc *cb, void *opaque)

{

    IscsiLun *iscsilun = bs->opaque;

    struct iscsi_context *iscsi = iscsilun->iscsi;

    IscsiAIOCB *acb;

static int iscsi_aio_discard_acb(IscsiAIOCB *acb) {

    struct iscsi_context *iscsi = acb->iscsilun->iscsi;

    struct unmap_list list[1];



    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);



    acb->iscsilun = iscsilun;

    acb->canceled   = 0;

    acb->bh         = NULL;

    acb->status     = -EINPROGRESS;

    acb->buf        = NULL;



    list[0].lba = sector_qemu2lun(sector_num, iscsilun);

    list[0].num = nb_sectors * BDRV_SECTOR_SIZE / iscsilun->block_size;

    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, iscsilun->lun,

    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) {

        if (acb->task) {

            scsi_free_scsi_task(acb->task);

        }

        qemu_aio_release(acb);

        return NULL;

    }