qemu

iscsi.c (81143B)

---

 /*
  * QEMU Block driver for iSCSI images
  *
  * Copyright (c) 2010-2011 Ronnie Sahlberg <ronniesahlberg@gmail.com>
  * Copyright (c) 2012-2017 Peter Lieven <pl@kamp.de>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 
 #include "qemu/osdep.h"
 
 #include <poll.h>
 #include <math.h>
 #include <arpa/inet.h>
 #include "sysemu/sysemu.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
 #include "qemu/bitops.h"
 #include "qemu/bitmap.h"
 #include "block/block_int.h"
 #include "block/qdict.h"
 #include "scsi/constants.h"
 #include "qemu/iov.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
 #include "qemu/uuid.h"
 #include "sysemu/replay.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-machine.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qstring.h"
 #include "crypto/secret.h"
 #include "scsi/utils.h"
 #include "trace.h"
 
 /* Conflict between scsi/utils.h and libiscsi! :( */
 #define SCSI_XFER_NONE ISCSI_XFER_NONE
 #include <iscsi/iscsi.h>
 #define inline __attribute__((gnu_inline))  /* required for libiscsi v1.9.0 */
 #include <iscsi/scsi-lowlevel.h>
 #undef inline
 #undef SCSI_XFER_NONE
 QEMU_BUILD_BUG_ON((int)SCSI_XFER_NONE != (int)ISCSI_XFER_NONE);
 
 #ifdef __linux__
 #include <scsi/sg.h>
 #endif
 
 typedef struct IscsiLun {
     struct iscsi_context *iscsi;
     AioContext *aio_context;
     int lun;
     enum scsi_inquiry_peripheral_device_type type;
     int block_size;
     uint64_t num_blocks;
     int events;
     QEMUTimer *nop_timer;
     QEMUTimer *event_timer;
     QemuMutex mutex;
     struct scsi_inquiry_logical_block_provisioning lbp;
     struct scsi_inquiry_block_limits bl;
     struct scsi_inquiry_device_designator *dd;
     unsigned char *zeroblock;
     /* The allocmap tracks which clusters (pages) on the iSCSI target are
      * allocated and which are not. In case a target returns zeros for
      * unallocated pages (iscsilun->lprz) we can directly return zeros instead
      * of reading zeros over the wire if a read request falls within an
      * unallocated block. As there are 3 possible states we need 2 bitmaps to
      * track. allocmap_valid keeps track if QEMU's information about a page is
      * valid. allocmap tracks if a page is allocated or not. In case QEMU has no
      * valid information about a page the corresponding allocmap entry should be
      * switched to unallocated as well to force a new lookup of the allocation
      * status as lookups are generally skipped if a page is suspect to be
      * allocated. If a iSCSI target is opened with cache.direct = on the
      * allocmap_valid does not exist turning all cached information invalid so
      * that a fresh lookup is made for any page even if allocmap entry returns
      * it's unallocated. */
     unsigned long *allocmap;
     unsigned long *allocmap_valid;
     long allocmap_size;
     int cluster_size;
     bool use_16_for_rw;
     bool write_protected;
     bool lbpme;
     bool lbprz;
     bool dpofua;
     bool has_write_same;
     bool request_timed_out;
 } IscsiLun;
 
 typedef struct IscsiTask {
     int status;
     int complete;
     int retries;
     int do_retry;
     struct scsi_task *task;
     Coroutine *co;
     IscsiLun *iscsilun;
     QEMUTimer retry_timer;
     int err_code;
     char *err_str;
 } IscsiTask;
 
 typedef struct IscsiAIOCB {
     BlockAIOCB common;
     QEMUBH *bh;
     IscsiLun *iscsilun;
     struct scsi_task *task;
     int status;
     int64_t sector_num;
     int nb_sectors;
     int ret;
 #ifdef __linux__
     sg_io_hdr_t *ioh;
 #endif
     bool cancelled;
 } IscsiAIOCB;
 
 /* libiscsi uses time_t so its enough to process events every second */
 #define EVENT_INTERVAL 1000
 #define NOP_INTERVAL 5000
 #define MAX_NOP_FAILURES 3
 #define ISCSI_CMD_RETRIES ARRAY_SIZE(iscsi_retry_times)
 static const unsigned iscsi_retry_times[] = {8, 32, 128, 512, 2048, 8192, 32768};
 
 /* this threshold is a trade-off knob to choose between
  * the potential additional overhead of an extra GET_LBA_STATUS request
  * vs. unnecessarily reading a lot of zero sectors over the wire.
  * If a read request is greater or equal than ISCSI_CHECKALLOC_THRES
  * sectors we check the allocation status of the area covered by the
  * request first if the allocationmap indicates that the area might be
  * unallocated. */
 #define ISCSI_CHECKALLOC_THRES 64
 
 #ifdef __linux__
 
 static void
 iscsi_bh_cb(void *p)
 {
     IscsiAIOCB *acb = p;
 
     qemu_bh_delete(acb->bh);
 
     acb->common.cb(acb->common.opaque, acb->status);
 
     if (acb->task != NULL) {
         scsi_free_scsi_task(acb->task);
         acb->task = NULL;
     }
 
     qemu_aio_unref(acb);
 }
 
 static void
 iscsi_schedule_bh(IscsiAIOCB *acb)
 {
     if (acb->bh) {
         return;
     }
     acb->bh = aio_bh_new(acb->iscsilun->aio_context, iscsi_bh_cb, acb);
     qemu_bh_schedule(acb->bh);
 }
 
 #endif
 
 static void iscsi_co_generic_bh_cb(void *opaque)
 {
     struct IscsiTask *iTask = opaque;
 
     iTask->complete = 1;
     aio_co_wake(iTask->co);
 }
 
 static void iscsi_retry_timer_expired(void *opaque)
 {
     struct IscsiTask *iTask = opaque;
     iTask->complete = 1;
     if (iTask->co) {
         aio_co_wake(iTask->co);
     }
 }
 
 static inline unsigned exp_random(double mean)
 {
     return -mean * log((double)rand() / RAND_MAX);
 }
 
 /* SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST was introduced in
  * libiscsi 1.10.0, together with other constants we need.  Use it as
  * a hint that we have to define them ourselves if needed, to keep the
  * minimum required libiscsi version at 1.9.0.  We use an ASCQ macro for
  * the test because SCSI_STATUS_* is an enum.
  *
  * To guard against future changes where SCSI_SENSE_ASCQ_* also becomes
  * an enum, check against the LIBISCSI_API_VERSION macro, which was
  * introduced in 1.11.0.  If it is present, there is no need to define
  * anything.
  */
 #if !defined(SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST) && \
     !defined(LIBISCSI_API_VERSION)
 #define SCSI_STATUS_TASK_SET_FULL                          0x28
 #define SCSI_STATUS_TIMEOUT                                0x0f000002
 #define SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST    0x2600
 #define SCSI_SENSE_ASCQ_PARAMETER_LIST_LENGTH_ERROR        0x1a00
 #endif
 
 #ifndef LIBISCSI_API_VERSION
 #define LIBISCSI_API_VERSION 20130701
 #endif
 
 static int iscsi_translate_sense(struct scsi_sense *sense)
 {
     return scsi_sense_to_errno(sense->key,
                                (sense->ascq & 0xFF00) >> 8,
                                sense->ascq & 0xFF);
 }
 
 /* Called (via iscsi_service) with QemuMutex held.  */
 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->status = status;
     iTask->do_retry = 0;
     iTask->err_code = 0;
     iTask->task = task;
 
     if (status != SCSI_STATUS_GOOD) {
         iTask->err_code = -EIO;
         if (iTask->retries++ < ISCSI_CMD_RETRIES) {
             if (status == SCSI_STATUS_BUSY ||
                 status == SCSI_STATUS_TIMEOUT ||
                 status == SCSI_STATUS_TASK_SET_FULL) {
                 unsigned retry_time =
                     exp_random(iscsi_retry_times[iTask->retries - 1]);
                 if (status == SCSI_STATUS_TIMEOUT) {
                     /* make sure the request is rescheduled AFTER the
                      * reconnect is initiated */
                     retry_time = EVENT_INTERVAL * 2;
                     iTask->iscsilun->request_timed_out = true;
                 }
                 error_report("iSCSI Busy/TaskSetFull/TimeOut"
                              " (retry #%u in %u ms): %s",
                              iTask->retries, retry_time,
                              iscsi_get_error(iscsi));
                 aio_timer_init(iTask->iscsilun->aio_context,
                                &iTask->retry_timer, QEMU_CLOCK_REALTIME,
                                SCALE_MS, iscsi_retry_timer_expired, iTask);
                 timer_mod(&iTask->retry_timer,
                           qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + retry_time);
                 iTask->do_retry = 1;
             } else if (status == SCSI_STATUS_CHECK_CONDITION) {
                 int error = iscsi_translate_sense(&task->sense);
                 if (error == EAGAIN) {
                     error_report("iSCSI CheckCondition: %s",
                                  iscsi_get_error(iscsi));
                     iTask->do_retry = 1;
                 } else {
                     iTask->err_code = -error;
                     iTask->err_str = g_strdup(iscsi_get_error(iscsi));
                 }
             }
         }
     }
 
     if (iTask->co) {
         replay_bh_schedule_oneshot_event(iTask->iscsilun->aio_context,
                                          iscsi_co_generic_bh_cb, iTask);
     } else {
         iTask->complete = 1;
     }
 }
 
 static void coroutine_fn
 iscsi_co_init_iscsitask(IscsiLun *iscsilun, struct IscsiTask *iTask)
 {
     *iTask = (struct IscsiTask) {
         .co         = qemu_coroutine_self(),
         .iscsilun   = iscsilun,
     };
 }
 
 #ifdef __linux__
 
 /* Called (via iscsi_service) with QemuMutex held. */
 static void
 iscsi_abort_task_cb(struct iscsi_context *iscsi, int status, void *command_data,
                     void *private_data)
 {
     IscsiAIOCB *acb = private_data;
 
     /* If the command callback hasn't been called yet, drop the task */
     if (!acb->bh) {
         /* Call iscsi_aio_ioctl_cb() with SCSI_STATUS_CANCELLED */
         iscsi_scsi_cancel_task(iscsi, acb->task);
     }
 
     qemu_aio_unref(acb); /* acquired in iscsi_aio_cancel() */
 }
 
 static void
 iscsi_aio_cancel(BlockAIOCB *blockacb)
 {
     IscsiAIOCB *acb = (IscsiAIOCB *)blockacb;
     IscsiLun *iscsilun = acb->iscsilun;
 
     WITH_QEMU_LOCK_GUARD(&iscsilun->mutex) {
 
         /* If it was cancelled or completed already, our work is done here */
         if (acb->cancelled || acb->status != -EINPROGRESS) {
             return;
         }
 
         acb->cancelled = true;
 
         qemu_aio_ref(acb); /* released in iscsi_abort_task_cb() */
 
         /* send a task mgmt call to the target to cancel the task on the target */
         if (iscsi_task_mgmt_abort_task_async(iscsilun->iscsi, acb->task,
                                              iscsi_abort_task_cb, acb) < 0) {
             qemu_aio_unref(acb); /* since iscsi_abort_task_cb() won't be called */
         }
     }
 }
 
 static const AIOCBInfo iscsi_aiocb_info = {
     .aiocb_size         = sizeof(IscsiAIOCB),
     .cancel_async       = iscsi_aio_cancel,
 };
 
 #endif
 
 static void iscsi_process_read(void *arg);
 static void iscsi_process_write(void *arg);
 
 /* Called with QemuMutex held.  */
 static void
 iscsi_set_events(IscsiLun *iscsilun)
 {
     struct iscsi_context *iscsi = iscsilun->iscsi;
     int ev = iscsi_which_events(iscsi);
 
     if (ev != iscsilun->events) {
         aio_set_fd_handler(iscsilun->aio_context, iscsi_get_fd(iscsi),
                            false,
                            (ev & POLLIN) ? iscsi_process_read : NULL,
                            (ev & POLLOUT) ? iscsi_process_write : NULL,
                            NULL, NULL,
                            iscsilun);
         iscsilun->events = ev;
     }
 }
 
 static void iscsi_timed_check_events(void *opaque)
 {
     IscsiLun *iscsilun = opaque;
 
     WITH_QEMU_LOCK_GUARD(&iscsilun->mutex) {
         /* check for timed out requests */
         iscsi_service(iscsilun->iscsi, 0);
 
         if (iscsilun->request_timed_out) {
             iscsilun->request_timed_out = false;
             iscsi_reconnect(iscsilun->iscsi);
         }
 
         /*
          * newer versions of libiscsi may return zero events. Ensure we are
          * able to return to service once this situation changes.
          */
         iscsi_set_events(iscsilun);
     }
 
     timer_mod(iscsilun->event_timer,
               qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + EVENT_INTERVAL);
 }
 
 static void
 iscsi_process_read(void *arg)
 {
     IscsiLun *iscsilun = arg;
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
     qemu_mutex_lock(&iscsilun->mutex);
     iscsi_service(iscsi, POLLIN);
     iscsi_set_events(iscsilun);
     qemu_mutex_unlock(&iscsilun->mutex);
 }
 
 static void
 iscsi_process_write(void *arg)
 {
     IscsiLun *iscsilun = arg;
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
     qemu_mutex_lock(&iscsilun->mutex);
     iscsi_service(iscsi, POLLOUT);
     iscsi_set_events(iscsilun);
     qemu_mutex_unlock(&iscsilun->mutex);
 }
 
 static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun)
 {
     return sector * iscsilun->block_size / BDRV_SECTOR_SIZE;
 }
 
 static int64_t sector_qemu2lun(int64_t sector, IscsiLun *iscsilun)
 {
     return sector * BDRV_SECTOR_SIZE / iscsilun->block_size;
 }
 
 static bool is_byte_request_lun_aligned(int64_t offset, int64_t bytes,
                                         IscsiLun *iscsilun)
 {
     if (offset % iscsilun->block_size || bytes % iscsilun->block_size) {
         error_report("iSCSI misaligned request: "
                      "iscsilun->block_size %u, offset %" PRIi64
                      ", bytes %" PRIi64,
                      iscsilun->block_size, offset, bytes);
         return false;
     }
     return true;
 }
 
 static bool is_sector_request_lun_aligned(int64_t sector_num, int nb_sectors,
                                           IscsiLun *iscsilun)
 {
     assert(nb_sectors <= BDRV_REQUEST_MAX_SECTORS);
     return is_byte_request_lun_aligned(sector_num << BDRV_SECTOR_BITS,
                                        nb_sectors << BDRV_SECTOR_BITS,
                                        iscsilun);
 }
 
 static void iscsi_allocmap_free(IscsiLun *iscsilun)
 {
     g_free(iscsilun->allocmap);
     g_free(iscsilun->allocmap_valid);
     iscsilun->allocmap = NULL;
     iscsilun->allocmap_valid = NULL;
 }
 
 
 static int iscsi_allocmap_init(IscsiLun *iscsilun, int open_flags)
 {
     iscsi_allocmap_free(iscsilun);
 
     assert(iscsilun->cluster_size);
     iscsilun->allocmap_size =
         DIV_ROUND_UP(iscsilun->num_blocks * iscsilun->block_size,
                      iscsilun->cluster_size);
 
     iscsilun->allocmap = bitmap_try_new(iscsilun->allocmap_size);
     if (!iscsilun->allocmap) {
         return -ENOMEM;
     }
 
     if (open_flags & BDRV_O_NOCACHE) {
         /* when cache.direct = on all allocmap entries are
          * treated as invalid to force a relookup of the block
          * status on every read request */
         return 0;
     }
 
     iscsilun->allocmap_valid = bitmap_try_new(iscsilun->allocmap_size);
     if (!iscsilun->allocmap_valid) {
         /* if we are under memory pressure free the allocmap as well */
         iscsi_allocmap_free(iscsilun);
         return -ENOMEM;
     }
 
     return 0;
 }
 
 static void
 iscsi_allocmap_update(IscsiLun *iscsilun, int64_t offset,
                       int64_t bytes, bool allocated, bool valid)
 {
     int64_t cl_num_expanded, nb_cls_expanded, cl_num_shrunk, nb_cls_shrunk;
 
     if (iscsilun->allocmap == NULL) {
         return;
     }
     /* expand to entirely contain all affected clusters */
     assert(iscsilun->cluster_size);
     cl_num_expanded = offset / iscsilun->cluster_size;
     nb_cls_expanded = DIV_ROUND_UP(offset + bytes,
                                    iscsilun->cluster_size) - cl_num_expanded;
     /* shrink to touch only completely contained clusters */
     cl_num_shrunk = DIV_ROUND_UP(offset, iscsilun->cluster_size);
     nb_cls_shrunk = (offset + bytes) / iscsilun->cluster_size - cl_num_shrunk;
     if (allocated) {
         bitmap_set(iscsilun->allocmap, cl_num_expanded, nb_cls_expanded);
     } else {
         if (nb_cls_shrunk > 0) {
             bitmap_clear(iscsilun->allocmap, cl_num_shrunk, nb_cls_shrunk);
         }
     }
 
     if (iscsilun->allocmap_valid == NULL) {
         return;
     }
     if (valid) {
         if (nb_cls_shrunk > 0) {
             bitmap_set(iscsilun->allocmap_valid, cl_num_shrunk, nb_cls_shrunk);
         }
     } else {
         bitmap_clear(iscsilun->allocmap_valid, cl_num_expanded,
                      nb_cls_expanded);
     }
 }
 
 static void
 iscsi_allocmap_set_allocated(IscsiLun *iscsilun, int64_t offset,
                              int64_t bytes)
 {
     iscsi_allocmap_update(iscsilun, offset, bytes, true, true);
 }
 
 static void
 iscsi_allocmap_set_unallocated(IscsiLun *iscsilun, int64_t offset,
                                int64_t bytes)
 {
     /* Note: if cache.direct=on the fifth argument to iscsi_allocmap_update
      * is ignored, so this will in effect be an iscsi_allocmap_set_invalid.
      */
     iscsi_allocmap_update(iscsilun, offset, bytes, false, true);
 }
 
 static void iscsi_allocmap_set_invalid(IscsiLun *iscsilun, int64_t offset,
                                        int64_t bytes)
 {
     iscsi_allocmap_update(iscsilun, offset, bytes, false, false);
 }
 
 static void iscsi_allocmap_invalidate(IscsiLun *iscsilun)
 {
     if (iscsilun->allocmap) {
         bitmap_zero(iscsilun->allocmap, iscsilun->allocmap_size);
     }
     if (iscsilun->allocmap_valid) {
         bitmap_zero(iscsilun->allocmap_valid, iscsilun->allocmap_size);
     }
 }
 
 static inline bool
 iscsi_allocmap_is_allocated(IscsiLun *iscsilun, int64_t offset,
                             int64_t bytes)
 {
     unsigned long size;
     if (iscsilun->allocmap == NULL) {
         return true;
     }
     assert(iscsilun->cluster_size);
     size = DIV_ROUND_UP(offset + bytes, iscsilun->cluster_size);
     return !(find_next_bit(iscsilun->allocmap, size,
                            offset / iscsilun->cluster_size) == size);
 }
 
 static inline bool iscsi_allocmap_is_valid(IscsiLun *iscsilun,
                                            int64_t offset, int64_t bytes)
 {
     unsigned long size;
     if (iscsilun->allocmap_valid == NULL) {
         return false;
     }
     assert(iscsilun->cluster_size);
     size = DIV_ROUND_UP(offset + bytes, iscsilun->cluster_size);
     return (find_next_zero_bit(iscsilun->allocmap_valid, size,
                                offset / iscsilun->cluster_size) == size);
 }
 
 static void coroutine_fn iscsi_co_wait_for_task(IscsiTask *iTask,
                                                 IscsiLun *iscsilun)
 {
     while (!iTask->complete) {
         iscsi_set_events(iscsilun);
         qemu_mutex_unlock(&iscsilun->mutex);
         qemu_coroutine_yield();
         qemu_mutex_lock(&iscsilun->mutex);
     }
 }
 
 static int coroutine_fn
 iscsi_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
                 QEMUIOVector *iov, int flags)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     uint64_t lba;
     uint32_t num_sectors;
     bool fua = flags & BDRV_REQ_FUA;
     int r = 0;
 
     if (fua) {
         assert(iscsilun->dpofua);
     }
     if (!is_sector_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
         return -EINVAL;
     }
 
     if (bs->bl.max_transfer) {
         assert(nb_sectors << BDRV_SECTOR_BITS <= bs->bl.max_transfer);
     }
 
     lba = sector_qemu2lun(sector_num, iscsilun);
     num_sectors = sector_qemu2lun(nb_sectors, iscsilun);
     iscsi_co_init_iscsitask(iscsilun, &iTask);
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
     if (iscsilun->use_16_for_rw) {
 #if LIBISCSI_API_VERSION >= (20160603)
         iTask.task = iscsi_write16_iov_task(iscsilun->iscsi, iscsilun->lun, lba,
                                             NULL, num_sectors * iscsilun->block_size,
                                             iscsilun->block_size, 0, 0, fua, 0, 0,
                                             iscsi_co_generic_cb, &iTask,
                                             (struct scsi_iovec *)iov->iov, iov->niov);
     } else {
         iTask.task = iscsi_write10_iov_task(iscsilun->iscsi, iscsilun->lun, lba,
                                             NULL, num_sectors * iscsilun->block_size,
                                             iscsilun->block_size, 0, 0, fua, 0, 0,
                                             iscsi_co_generic_cb, &iTask,
                                             (struct scsi_iovec *)iov->iov, iov->niov);
     }
 #else
         iTask.task = iscsi_write16_task(iscsilun->iscsi, iscsilun->lun, lba,
                                         NULL, num_sectors * iscsilun->block_size,
                                         iscsilun->block_size, 0, 0, fua, 0, 0,
                                         iscsi_co_generic_cb, &iTask);
     } else {
         iTask.task = iscsi_write10_task(iscsilun->iscsi, iscsilun->lun, lba,
                                         NULL, num_sectors * iscsilun->block_size,
                                         iscsilun->block_size, 0, 0, fua, 0, 0,
                                         iscsi_co_generic_cb, &iTask);
     }
 #endif
     if (iTask.task == NULL) {
         qemu_mutex_unlock(&iscsilun->mutex);
         return -ENOMEM;
     }
 #if LIBISCSI_API_VERSION < (20160603)
     scsi_task_set_iov_out(iTask.task, (struct scsi_iovec *) iov->iov,
                           iov->niov);
 #endif
     iscsi_co_wait_for_task(&iTask, iscsilun);
 
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
         iTask.task = NULL;
     }
 
     if (iTask.do_retry) {
         iTask.complete = 0;
         goto retry;
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
         iscsi_allocmap_set_invalid(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                    nb_sectors * BDRV_SECTOR_SIZE);
         error_report("iSCSI WRITE10/16 failed at lba %" PRIu64 ": %s", lba,
                      iTask.err_str);
         r = iTask.err_code;
         goto out_unlock;
     }
 
     iscsi_allocmap_set_allocated(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                  nb_sectors * BDRV_SECTOR_SIZE);
 
 out_unlock:
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
     return r;
 }
 
 
 
 static int coroutine_fn iscsi_co_block_status(BlockDriverState *bs,
                                               bool want_zero, int64_t offset,
                                               int64_t bytes, int64_t *pnum,
                                               int64_t *map,
                                               BlockDriverState **file)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct scsi_get_lba_status *lbas = NULL;
     struct scsi_lba_status_descriptor *lbasd = NULL;
     struct IscsiTask iTask;
     uint64_t lba, max_bytes;
     int ret;
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
 
     assert(QEMU_IS_ALIGNED(offset | bytes, iscsilun->block_size));
 
     /* default to all sectors allocated */
     ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
     if (map) {
         *map = offset;
     }
     *pnum = bytes;
 
     /* LUN does not support logical block provisioning */
     if (!iscsilun->lbpme) {
         goto out;
     }
 
     lba = offset / iscsilun->block_size;
     max_bytes = (iscsilun->num_blocks - lba) * iscsilun->block_size;
 
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
     if (iscsi_get_lba_status_task(iscsilun->iscsi, iscsilun->lun,
                                   lba, 8 + 16, iscsi_co_generic_cb,
                                   &iTask) == NULL) {
         ret = -ENOMEM;
         goto out_unlock;
     }
     iscsi_co_wait_for_task(&iTask, iscsilun);
 
     if (iTask.do_retry) {
         if (iTask.task != NULL) {
             scsi_free_scsi_task(iTask.task);
             iTask.task = NULL;
         }
         iTask.complete = 0;
         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 compatibility */
         error_report("iSCSI GET_LBA_STATUS failed at lba %" PRIu64 ": %s",
                      lba, iTask.err_str);
         goto out_unlock;
     }
 
     lbas = scsi_datain_unmarshall(iTask.task);
     if (lbas == NULL || lbas->num_descriptors == 0) {
         ret = -EIO;
         goto out_unlock;
     }
 
     lbasd = &lbas->descriptors[0];
 
     if (lba != lbasd->lba) {
         ret = -EIO;
         goto out_unlock;
     }
 
     *pnum = MIN((int64_t) lbasd->num_blocks * iscsilun->block_size, max_bytes);
 
     if (lbasd->provisioning == SCSI_PROVISIONING_TYPE_DEALLOCATED ||
         lbasd->provisioning == SCSI_PROVISIONING_TYPE_ANCHORED) {
         ret &= ~BDRV_BLOCK_DATA;
         if (iscsilun->lbprz) {
             ret |= BDRV_BLOCK_ZERO;
         }
     }
 
     if (ret & BDRV_BLOCK_ZERO) {
         iscsi_allocmap_set_unallocated(iscsilun, offset, *pnum);
     } else {
         iscsi_allocmap_set_allocated(iscsilun, offset, *pnum);
     }
 
 out_unlock:
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
 out:
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
     }
     if (ret > 0 && ret & BDRV_BLOCK_OFFSET_VALID && file) {
         *file = bs;
     }
     return ret;
 }
 
 static int coroutine_fn iscsi_co_readv(BlockDriverState *bs,
                                        int64_t sector_num, int nb_sectors,
                                        QEMUIOVector *iov)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     uint64_t lba;
     uint32_t num_sectors;
     int r = 0;
 
     if (!is_sector_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
         return -EINVAL;
     }
 
     if (bs->bl.max_transfer) {
         assert(nb_sectors << BDRV_SECTOR_BITS <= bs->bl.max_transfer);
     }
 
     /* if cache.direct is off and we have a valid entry in our allocation map
      * we can skip checking the block status and directly return zeroes if
      * the request falls within an unallocated area */
     if (iscsi_allocmap_is_valid(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                 nb_sectors * BDRV_SECTOR_SIZE) &&
         !iscsi_allocmap_is_allocated(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                      nb_sectors * BDRV_SECTOR_SIZE)) {
             qemu_iovec_memset(iov, 0, 0x00, iov->size);
             return 0;
     }
 
     if (nb_sectors >= ISCSI_CHECKALLOC_THRES &&
         !iscsi_allocmap_is_valid(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                  nb_sectors * BDRV_SECTOR_SIZE) &&
         !iscsi_allocmap_is_allocated(iscsilun, sector_num * BDRV_SECTOR_SIZE,
                                      nb_sectors * BDRV_SECTOR_SIZE)) {
         int64_t pnum;
         /* check the block status from the beginning of the cluster
          * containing the start sector */
         int64_t head;
         int ret;
 
         assert(iscsilun->cluster_size);
         head = (sector_num * BDRV_SECTOR_SIZE) % iscsilun->cluster_size;
         ret = iscsi_co_block_status(bs, true,
                                     sector_num * BDRV_SECTOR_SIZE - head,
                                     BDRV_REQUEST_MAX_BYTES, &pnum, NULL, NULL);
         if (ret < 0) {
             return ret;
         }
         /* if the whole request falls into an unallocated area we can avoid
          * reading and directly return zeroes instead */
         if (ret & BDRV_BLOCK_ZERO &&
             pnum >= nb_sectors * BDRV_SECTOR_SIZE + head) {
             qemu_iovec_memset(iov, 0, 0x00, iov->size);
             return 0;
         }
     }
 
     lba = sector_qemu2lun(sector_num, iscsilun);
     num_sectors = sector_qemu2lun(nb_sectors, iscsilun);
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
     if (iscsilun->use_16_for_rw) {
 #if LIBISCSI_API_VERSION >= (20160603)
         iTask.task = iscsi_read16_iov_task(iscsilun->iscsi, iscsilun->lun, lba,
                                            num_sectors * iscsilun->block_size,
                                            iscsilun->block_size, 0, 0, 0, 0, 0,
                                            iscsi_co_generic_cb, &iTask,
                                            (struct scsi_iovec *)iov->iov, iov->niov);
     } else {
         iTask.task = iscsi_read10_iov_task(iscsilun->iscsi, iscsilun->lun, lba,
                                            num_sectors * iscsilun->block_size,
                                            iscsilun->block_size,
                                            0, 0, 0, 0, 0,
                                            iscsi_co_generic_cb, &iTask,
                                            (struct scsi_iovec *)iov->iov, iov->niov);
     }
 #else
         iTask.task = iscsi_read16_task(iscsilun->iscsi, iscsilun->lun, lba,
                                        num_sectors * iscsilun->block_size,
                                        iscsilun->block_size, 0, 0, 0, 0, 0,
                                        iscsi_co_generic_cb, &iTask);
     } else {
         iTask.task = iscsi_read10_task(iscsilun->iscsi, iscsilun->lun, lba,
                                        num_sectors * iscsilun->block_size,
                                        iscsilun->block_size,
                                        0, 0, 0, 0, 0,
                                        iscsi_co_generic_cb, &iTask);
     }
 #endif
     if (iTask.task == NULL) {
         qemu_mutex_unlock(&iscsilun->mutex);
         return -ENOMEM;
     }
 #if LIBISCSI_API_VERSION < (20160603)
     scsi_task_set_iov_in(iTask.task, (struct scsi_iovec *) iov->iov, iov->niov);
 #endif
 
     iscsi_co_wait_for_task(&iTask, iscsilun);
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
         iTask.task = NULL;
     }
 
     if (iTask.do_retry) {
         iTask.complete = 0;
         goto retry;
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
         error_report("iSCSI READ10/16 failed at lba %" PRIu64 ": %s",
                      lba, iTask.err_str);
         r = iTask.err_code;
     }
 
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
     return r;
 }
 
 static int coroutine_fn iscsi_co_flush(BlockDriverState *bs)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     int r = 0;
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
     if (iscsi_synchronizecache10_task(iscsilun->iscsi, iscsilun->lun, 0, 0, 0,
                                       0, iscsi_co_generic_cb, &iTask) == NULL) {
         qemu_mutex_unlock(&iscsilun->mutex);
         return -ENOMEM;
     }
 
     iscsi_co_wait_for_task(&iTask, iscsilun);
 
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
         iTask.task = NULL;
     }
 
     if (iTask.do_retry) {
         iTask.complete = 0;
         goto retry;
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
         error_report("iSCSI SYNCHRONIZECACHE10 failed: %s", iTask.err_str);
         r = iTask.err_code;
     }
 
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
     return r;
 }
 
 #ifdef __linux__
 /* Called (via iscsi_service) with QemuMutex held.  */
 static void
 iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
                      void *command_data, void *opaque)
 {
     IscsiAIOCB *acb = opaque;
 
     if (status == SCSI_STATUS_CANCELLED) {
         if (!acb->bh) {
             acb->status = -ECANCELED;
             iscsi_schedule_bh(acb);
         }
         return;
     }
 
     acb->status = 0;
     if (status < 0) {
         error_report("Failed to ioctl(SG_IO) to iSCSI lun. %s",
                      iscsi_get_error(iscsi));
         acb->status = -iscsi_translate_sense(&acb->task->sense);
     }
 
     acb->ioh->driver_status = 0;
     acb->ioh->host_status   = 0;
     acb->ioh->resid         = 0;
     acb->ioh->status        = status;
 
 #define SG_ERR_DRIVER_SENSE    0x08
 
     if (status == SCSI_STATUS_CHECK_CONDITION && acb->task->datain.size >= 2) {
         int ss;
 
         acb->ioh->driver_status |= SG_ERR_DRIVER_SENSE;
 
         acb->ioh->sb_len_wr = acb->task->datain.size - 2;
         ss = MIN(acb->ioh->mx_sb_len, acb->ioh->sb_len_wr);
         memcpy(acb->ioh->sbp, &acb->task->datain.data[2], ss);
     }
 
     iscsi_schedule_bh(acb);
 }
 
 static void iscsi_ioctl_bh_completion(void *opaque)
 {
     IscsiAIOCB *acb = opaque;
 
     qemu_bh_delete(acb->bh);
     acb->common.cb(acb->common.opaque, acb->ret);
     qemu_aio_unref(acb);
 }
 
 static void iscsi_ioctl_handle_emulated(IscsiAIOCB *acb, int req, void *buf)
 {
     BlockDriverState *bs = acb->common.bs;
     IscsiLun *iscsilun = bs->opaque;
     int ret = 0;
 
     switch (req) {
     case SG_GET_VERSION_NUM:
         *(int *)buf = 30000;
         break;
     case SG_GET_SCSI_ID:
         ((struct sg_scsi_id *)buf)->scsi_type = iscsilun->type;
         break;
     default:
         ret = -EINVAL;
     }
     assert(!acb->bh);
     acb->bh = aio_bh_new(bdrv_get_aio_context(bs),
                          iscsi_ioctl_bh_completion, acb);
     acb->ret = ret;
     qemu_bh_schedule(acb->bh);
 }
 
 static BlockAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
         unsigned long int req, void *buf,
         BlockCompletionFunc *cb, void *opaque)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct iscsi_context *iscsi = iscsilun->iscsi;
     struct iscsi_data data;
     IscsiAIOCB *acb;
 
     acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
 
     acb->iscsilun = iscsilun;
     acb->bh          = NULL;
     acb->status      = -EINPROGRESS;
     acb->ioh         = buf;
     acb->cancelled   = false;
 
     if (req != SG_IO) {
         iscsi_ioctl_handle_emulated(acb, req, buf);
         return &acb->common;
     }
 
     if (acb->ioh->cmd_len > SCSI_CDB_MAX_SIZE) {
         error_report("iSCSI: ioctl error CDB exceeds max size (%d > %d)",
                      acb->ioh->cmd_len, SCSI_CDB_MAX_SIZE);
         qemu_aio_unref(acb);
         return NULL;
     }
 
     acb->task = malloc(sizeof(struct scsi_task));
     if (acb->task == NULL) {
         error_report("iSCSI: Failed to allocate task for scsi command. %s",
                      iscsi_get_error(iscsi));
         qemu_aio_unref(acb);
         return NULL;
     }
     memset(acb->task, 0, sizeof(struct scsi_task));
 
     switch (acb->ioh->dxfer_direction) {
     case SG_DXFER_TO_DEV:
         acb->task->xfer_dir = SCSI_XFER_WRITE;
         break;
     case SG_DXFER_FROM_DEV:
         acb->task->xfer_dir = SCSI_XFER_READ;
         break;
     default:
         acb->task->xfer_dir = SCSI_XFER_NONE;
         break;
     }
 
     acb->task->cdb_size = acb->ioh->cmd_len;
     memcpy(&acb->task->cdb[0], acb->ioh->cmdp, acb->ioh->cmd_len);
     acb->task->expxferlen = acb->ioh->dxfer_len;
 
     data.size = 0;
     qemu_mutex_lock(&iscsilun->mutex);
     if (acb->task->xfer_dir == SCSI_XFER_WRITE) {
         if (acb->ioh->iovec_count == 0) {
             data.data = acb->ioh->dxferp;
             data.size = acb->ioh->dxfer_len;
         } else {
             scsi_task_set_iov_out(acb->task,
                                  (struct scsi_iovec *) acb->ioh->dxferp,
                                  acb->ioh->iovec_count);
         }
     }
 
     if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
                                  iscsi_aio_ioctl_cb,
                                  (data.size > 0) ? &data : NULL,
                                  acb) != 0) {
         qemu_mutex_unlock(&iscsilun->mutex);
         scsi_free_scsi_task(acb->task);
         qemu_aio_unref(acb);
         return NULL;
     }
 
     /* tell libiscsi to read straight into the buffer we got from ioctl */
     if (acb->task->xfer_dir == SCSI_XFER_READ) {
         if (acb->ioh->iovec_count == 0) {
             scsi_task_add_data_in_buffer(acb->task,
                                          acb->ioh->dxfer_len,
                                          acb->ioh->dxferp);
         } else {
             scsi_task_set_iov_in(acb->task,
                                  (struct scsi_iovec *) acb->ioh->dxferp,
                                  acb->ioh->iovec_count);
         }
     }
 
     iscsi_set_events(iscsilun);
     qemu_mutex_unlock(&iscsilun->mutex);
 
     return &acb->common;
 }
 
 #endif
 
 static int64_t
 iscsi_getlength(BlockDriverState *bs)
 {
     IscsiLun *iscsilun = bs->opaque;
     int64_t len;
 
     len  = iscsilun->num_blocks;
     len *= iscsilun->block_size;
 
     return len;
 }
 
 static int
 coroutine_fn iscsi_co_pdiscard(BlockDriverState *bs, int64_t offset,
                                int64_t bytes)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     struct unmap_list list;
     int r = 0;
 
     if (!is_byte_request_lun_aligned(offset, bytes, iscsilun)) {
         return -ENOTSUP;
     }
 
     if (!iscsilun->lbp.lbpu) {
         /* UNMAP is not supported by the target */
         return 0;
     }
 
     /*
      * We don't want to overflow list.num which is uint32_t.
      * We rely on our max_pdiscard.
      */
     assert(bytes / iscsilun->block_size <= UINT32_MAX);
 
     list.lba = offset / iscsilun->block_size;
     list.num = bytes / iscsilun->block_size;
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
     qemu_mutex_lock(&iscsilun->mutex);
 retry:
     if (iscsi_unmap_task(iscsilun->iscsi, iscsilun->lun, 0, 0, &list, 1,
                          iscsi_co_generic_cb, &iTask) == NULL) {
         r = -ENOMEM;
         goto out_unlock;
     }
 
     iscsi_co_wait_for_task(&iTask, iscsilun);
 
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
         iTask.task = NULL;
     }
 
     if (iTask.do_retry) {
         iTask.complete = 0;
         goto retry;
     }
 
     iscsi_allocmap_set_invalid(iscsilun, offset, bytes);
 
     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 */
         goto out_unlock;
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
         error_report("iSCSI UNMAP failed at lba %" PRIu64 ": %s",
                      list.lba, iTask.err_str);
         r = iTask.err_code;
         goto out_unlock;
     }
 
 out_unlock:
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
     return r;
 }
 
 static int
 coroutine_fn iscsi_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
                                     int64_t bytes, BdrvRequestFlags flags)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct IscsiTask iTask;
     uint64_t lba;
     uint64_t nb_blocks;
     bool use_16_for_ws = iscsilun->use_16_for_rw;
     int r = 0;
 
     if (!is_byte_request_lun_aligned(offset, bytes, iscsilun)) {
         return -ENOTSUP;
     }
 
     if (flags & BDRV_REQ_MAY_UNMAP) {
         if (!use_16_for_ws && !iscsilun->lbp.lbpws10) {
             /* WRITESAME10 with UNMAP is unsupported try WRITESAME16 */
             use_16_for_ws = true;
         }
         if (use_16_for_ws && !iscsilun->lbp.lbpws) {
             /* WRITESAME16 with UNMAP is not supported by the target,
              * fall back and try WRITESAME10/16 without UNMAP */
             flags &= ~BDRV_REQ_MAY_UNMAP;
             use_16_for_ws = iscsilun->use_16_for_rw;
         }
     }
 
     if (!(flags & BDRV_REQ_MAY_UNMAP) && !iscsilun->has_write_same) {
         /* WRITESAME without UNMAP is not supported by the target */
         return -ENOTSUP;
     }
 
     lba = offset / iscsilun->block_size;
     nb_blocks = bytes / iscsilun->block_size;
 
     if (iscsilun->zeroblock == NULL) {
         iscsilun->zeroblock = g_try_malloc0(iscsilun->block_size);
         if (iscsilun->zeroblock == NULL) {
             return -ENOMEM;
         }
     }
 
     qemu_mutex_lock(&iscsilun->mutex);
     iscsi_co_init_iscsitask(iscsilun, &iTask);
 retry:
     if (use_16_for_ws) {
         /*
          * iscsi_writesame16_task num_blocks argument is uint32_t. We rely here
          * on our max_pwrite_zeroes limit.
          */
         assert(nb_blocks <= UINT32_MAX);
         iTask.task = iscsi_writesame16_task(iscsilun->iscsi, iscsilun->lun, lba,
                                             iscsilun->zeroblock, iscsilun->block_size,
                                             nb_blocks, 0, !!(flags & BDRV_REQ_MAY_UNMAP),
                                             0, 0, iscsi_co_generic_cb, &iTask);
     } else {
         /*
          * iscsi_writesame10_task num_blocks argument is uint16_t. We rely here
          * on our max_pwrite_zeroes limit.
          */
         assert(nb_blocks <= UINT16_MAX);
         iTask.task = iscsi_writesame10_task(iscsilun->iscsi, iscsilun->lun, lba,
                                             iscsilun->zeroblock, iscsilun->block_size,
                                             nb_blocks, 0, !!(flags & BDRV_REQ_MAY_UNMAP),
                                             0, 0, iscsi_co_generic_cb, &iTask);
     }
     if (iTask.task == NULL) {
         qemu_mutex_unlock(&iscsilun->mutex);
         return -ENOMEM;
     }
 
     iscsi_co_wait_for_task(&iTask, iscsilun);
 
     if (iTask.status == SCSI_STATUS_CHECK_CONDITION &&
         iTask.task->sense.key == SCSI_SENSE_ILLEGAL_REQUEST &&
         (iTask.task->sense.ascq == SCSI_SENSE_ASCQ_INVALID_OPERATION_CODE ||
          iTask.task->sense.ascq == SCSI_SENSE_ASCQ_INVALID_FIELD_IN_CDB)) {
         /* WRITE SAME is not supported by the target */
         iscsilun->has_write_same = false;
         scsi_free_scsi_task(iTask.task);
         r = -ENOTSUP;
         goto out_unlock;
     }
 
     if (iTask.task != NULL) {
         scsi_free_scsi_task(iTask.task);
         iTask.task = NULL;
     }
 
     if (iTask.do_retry) {
         iTask.complete = 0;
         goto retry;
     }
 
     if (iTask.status != SCSI_STATUS_GOOD) {
         iscsi_allocmap_set_invalid(iscsilun, offset, bytes);
         error_report("iSCSI WRITESAME10/16 failed at lba %" PRIu64 ": %s",
                      lba, iTask.err_str);
         r = iTask.err_code;
         goto out_unlock;
     }
 
     if (flags & BDRV_REQ_MAY_UNMAP) {
         iscsi_allocmap_set_invalid(iscsilun, offset, bytes);
     } else {
         iscsi_allocmap_set_allocated(iscsilun, offset, bytes);
     }
 
 out_unlock:
     qemu_mutex_unlock(&iscsilun->mutex);
     g_free(iTask.err_str);
     return r;
 }
 
 static void apply_chap(struct iscsi_context *iscsi, QemuOpts *opts,
                        Error **errp)
 {
     const char *user = NULL;
     const char *password = NULL;
     const char *secretid;
     char *secret = NULL;
 
     user = qemu_opt_get(opts, "user");
     if (!user) {
         return;
     }
 
     secretid = qemu_opt_get(opts, "password-secret");
     password = qemu_opt_get(opts, "password");
     if (secretid && password) {
         error_setg(errp, "'password' and 'password-secret' properties are "
                    "mutually exclusive");
         return;
     }
     if (secretid) {
         secret = qcrypto_secret_lookup_as_utf8(secretid, errp);
         if (!secret) {
             return;
         }
         password = secret;
     } else if (!password) {
         error_setg(errp, "CHAP username specified but no password was given");
         return;
     }
 
     if (iscsi_set_initiator_username_pwd(iscsi, user, password)) {
         error_setg(errp, "Failed to set initiator username and password");
     }
 
     g_free(secret);
 }
 
 static void apply_header_digest(struct iscsi_context *iscsi, QemuOpts *opts,
                                 Error **errp)
 {
     const char *digest = NULL;
 
     digest = qemu_opt_get(opts, "header-digest");
     if (!digest) {
         iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE_CRC32C);
     } else if (!strcmp(digest, "crc32c")) {
         iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_CRC32C);
     } else if (!strcmp(digest, "none")) {
         iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE);
     } else if (!strcmp(digest, "crc32c-none")) {
         iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_CRC32C_NONE);
     } else if (!strcmp(digest, "none-crc32c")) {
         iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE_CRC32C);
     } else {
         error_setg(errp, "Invalid header-digest setting : %s", digest);
     }
 }
 
 static char *get_initiator_name(QemuOpts *opts)
 {
     const char *name;
     char *iscsi_name;
     UuidInfo *uuid_info;
 
     name = qemu_opt_get(opts, "initiator-name");
     if (name) {
         return g_strdup(name);
     }
 
     uuid_info = qmp_query_uuid(NULL);
     if (strcmp(uuid_info->UUID, UUID_NONE) == 0) {
         name = qemu_get_vm_name();
     } else {
         name = uuid_info->UUID;
     }
     iscsi_name = g_strdup_printf("iqn.2008-11.org.linux-kvm%s%s",
                                  name ? ":" : "", name ? name : "");
     qapi_free_UuidInfo(uuid_info);
     return iscsi_name;
 }
 
 static void iscsi_nop_timed_event(void *opaque)
 {
     IscsiLun *iscsilun = opaque;
 
     QEMU_LOCK_GUARD(&iscsilun->mutex);
     if (iscsi_get_nops_in_flight(iscsilun->iscsi) >= MAX_NOP_FAILURES) {
         error_report("iSCSI: NOP timeout. Reconnecting...");
         iscsilun->request_timed_out = true;
     } else if (iscsi_nop_out_async(iscsilun->iscsi, NULL, NULL, 0, NULL) != 0) {
         error_report("iSCSI: failed to sent NOP-Out. Disabling NOP messages.");
         return;
     }
 
     timer_mod(iscsilun->nop_timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + NOP_INTERVAL);
     iscsi_set_events(iscsilun);
 }
 
 static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
 {
     struct scsi_task *task = NULL;
     struct scsi_readcapacity10 *rc10 = NULL;
     struct scsi_readcapacity16 *rc16 = NULL;
     int retries = ISCSI_CMD_RETRIES; 
 
     do {
         if (task != NULL) {
             scsi_free_scsi_task(task);
             task = NULL;
         }
 
         switch (iscsilun->type) {
         case TYPE_DISK:
             task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
             if (task != NULL && task->status == SCSI_STATUS_GOOD) {
                 rc16 = scsi_datain_unmarshall(task);
                 if (rc16 == NULL) {
                     error_setg(errp, "iSCSI: Failed to unmarshall readcapacity16 data.");
                 } else {
                     iscsilun->block_size = rc16->block_length;
                     iscsilun->num_blocks = rc16->returned_lba + 1;
                     iscsilun->lbpme = !!rc16->lbpme;
                     iscsilun->lbprz = !!rc16->lbprz;
                     iscsilun->use_16_for_rw = (rc16->returned_lba > 0xffffffff);
                 }
                 break;
             }
             if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
                 && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) {
                 break;
             }
             /* Fall through and try READ CAPACITY(10) instead.  */
         case TYPE_ROM:
             task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);
             if (task != NULL && task->status == SCSI_STATUS_GOOD) {
                 rc10 = scsi_datain_unmarshall(task);
                 if (rc10 == NULL) {
                     error_setg(errp, "iSCSI: Failed to unmarshall readcapacity10 data.");
                 } else {
                     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:
             return;
         }
     } while (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
              && task->sense.key == SCSI_SENSE_UNIT_ATTENTION
              && retries-- > 0);
 
     if (task == NULL || task->status != SCSI_STATUS_GOOD) {
         error_setg(errp, "iSCSI: failed to send readcapacity10/16 command");
     } else if (!iscsilun->block_size ||
                iscsilun->block_size % BDRV_SECTOR_SIZE) {
         error_setg(errp, "iSCSI: the target returned an invalid "
                    "block size of %d.", iscsilun->block_size);
     }
     if (task) {
         scsi_free_scsi_task(task);
     }
 }
 
 static struct scsi_task *iscsi_do_inquiry(struct iscsi_context *iscsi, int lun,
                                           int evpd, int pc, void **inq, Error **errp)
 {
     int full_size;
     struct scsi_task *task = NULL;
     task = iscsi_inquiry_sync(iscsi, lun, evpd, pc, 64);
     if (task == NULL || task->status != SCSI_STATUS_GOOD) {
         goto fail;
     }
     full_size = scsi_datain_getfullsize(task);
     if (full_size > task->datain.size) {
         scsi_free_scsi_task(task);
 
         /* we need more data for the full list */
         task = iscsi_inquiry_sync(iscsi, lun, evpd, pc, full_size);
         if (task == NULL || task->status != SCSI_STATUS_GOOD) {
             goto fail;
         }
     }
 
     *inq = scsi_datain_unmarshall(task);
     if (*inq == NULL) {
         error_setg(errp, "iSCSI: failed to unmarshall inquiry datain blob");
         goto fail_with_err;
     }
 
     return task;
 
 fail:
     error_setg(errp, "iSCSI: Inquiry command failed : %s",
                iscsi_get_error(iscsi));
 fail_with_err:
     if (task != NULL) {
         scsi_free_scsi_task(task);
     }
     return NULL;
 }
 
 static void iscsi_detach_aio_context(BlockDriverState *bs)
 {
     IscsiLun *iscsilun = bs->opaque;
 
     aio_set_fd_handler(iscsilun->aio_context, iscsi_get_fd(iscsilun->iscsi),
                        false, NULL, NULL, NULL, NULL, NULL);
     iscsilun->events = 0;
 
     if (iscsilun->nop_timer) {
         timer_free(iscsilun->nop_timer);
         iscsilun->nop_timer = NULL;
     }
     if (iscsilun->event_timer) {
         timer_free(iscsilun->event_timer);
         iscsilun->event_timer = NULL;
     }
 }
 
 static void iscsi_attach_aio_context(BlockDriverState *bs,
                                      AioContext *new_context)
 {
     IscsiLun *iscsilun = bs->opaque;
 
     iscsilun->aio_context = new_context;
     iscsi_set_events(iscsilun);
 
     /* Set up a timer for sending out iSCSI NOPs */
     iscsilun->nop_timer = aio_timer_new(iscsilun->aio_context,
                                         QEMU_CLOCK_REALTIME, SCALE_MS,
                                         iscsi_nop_timed_event, iscsilun);
     timer_mod(iscsilun->nop_timer,
               qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + NOP_INTERVAL);
 
     /* Set up a timer for periodic calls to iscsi_set_events and to
      * scan for command timeout */
     iscsilun->event_timer = aio_timer_new(iscsilun->aio_context,
                                           QEMU_CLOCK_REALTIME, SCALE_MS,
                                           iscsi_timed_check_events, iscsilun);
     timer_mod(iscsilun->event_timer,
               qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + EVENT_INTERVAL);
 }
 
 static void iscsi_modesense_sync(IscsiLun *iscsilun)
 {
     struct scsi_task *task;
     struct scsi_mode_sense *ms = NULL;
     iscsilun->write_protected = false;
     iscsilun->dpofua = false;
 
     task = iscsi_modesense6_sync(iscsilun->iscsi, iscsilun->lun,
                                  1, SCSI_MODESENSE_PC_CURRENT,
                                  0x3F, 0, 255);
     if (task == NULL) {
         error_report("iSCSI: Failed to send MODE_SENSE(6) command: %s",
                      iscsi_get_error(iscsilun->iscsi));
         goto out;
     }
 
     if (task->status != SCSI_STATUS_GOOD) {
         error_report("iSCSI: Failed MODE_SENSE(6), LUN assumed writable");
         goto out;
     }
     ms = scsi_datain_unmarshall(task);
     if (!ms) {
         error_report("iSCSI: Failed to unmarshall MODE_SENSE(6) data: %s",
                      iscsi_get_error(iscsilun->iscsi));
         goto out;
     }
     iscsilun->write_protected = ms->device_specific_parameter & 0x80;
     iscsilun->dpofua          = ms->device_specific_parameter & 0x10;
 
 out:
     if (task) {
         scsi_free_scsi_task(task);
     }
 }
 
 static void iscsi_parse_iscsi_option(const char *target, QDict *options)
 {
     QemuOptsList *list;
     QemuOpts *opts;
     const char *user, *password, *password_secret, *initiator_name,
                *header_digest, *timeout;
 
     list = qemu_find_opts("iscsi");
     if (!list) {
         return;
     }
 
     opts = qemu_opts_find(list, target);
     if (opts == NULL) {
         opts = QTAILQ_FIRST(&list->head);
         if (!opts) {
             return;
         }
     }
 
     user = qemu_opt_get(opts, "user");
     if (user) {
         qdict_set_default_str(options, "user", user);
     }
 
     password = qemu_opt_get(opts, "password");
     if (password) {
         qdict_set_default_str(options, "password", password);
     }
 
     password_secret = qemu_opt_get(opts, "password-secret");
     if (password_secret) {
         qdict_set_default_str(options, "password-secret", password_secret);
     }
 
     initiator_name = qemu_opt_get(opts, "initiator-name");
     if (initiator_name) {
         qdict_set_default_str(options, "initiator-name", initiator_name);
     }
 
     header_digest = qemu_opt_get(opts, "header-digest");
     if (header_digest) {
         /* -iscsi takes upper case values, but QAPI only supports lower case
          * enum constant names, so we have to convert here. */
         char *qapi_value = g_ascii_strdown(header_digest, -1);
         qdict_set_default_str(options, "header-digest", qapi_value);
         g_free(qapi_value);
     }
 
     timeout = qemu_opt_get(opts, "timeout");
     if (timeout) {
         qdict_set_default_str(options, "timeout", timeout);
     }
 }
 
 /*
  * We support iscsi url's on the form
  * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
  */
 static void iscsi_parse_filename(const char *filename, QDict *options,
                                  Error **errp)
 {
     struct iscsi_url *iscsi_url;
     const char *transport_name;
     char *lun_str;
 
     iscsi_url = iscsi_parse_full_url(NULL, filename);
     if (iscsi_url == NULL) {
         error_setg(errp, "Failed to parse URL : %s", filename);
         return;
     }
 
 #if LIBISCSI_API_VERSION >= (20160603)
     switch (iscsi_url->transport) {
     case TCP_TRANSPORT:
         transport_name = "tcp";
         break;
     case ISER_TRANSPORT:
         transport_name = "iser";
         break;
     default:
         error_setg(errp, "Unknown transport type (%d)",
                    iscsi_url->transport);
         return;
     }
 #else
     transport_name = "tcp";
 #endif
 
     qdict_set_default_str(options, "transport", transport_name);
     qdict_set_default_str(options, "portal", iscsi_url->portal);
     qdict_set_default_str(options, "target", iscsi_url->target);
 
     lun_str = g_strdup_printf("%d", iscsi_url->lun);
     qdict_set_default_str(options, "lun", lun_str);
     g_free(lun_str);
 
     /* User/password from -iscsi take precedence over those from the URL */
     iscsi_parse_iscsi_option(iscsi_url->target, options);
 
     if (iscsi_url->user[0] != '\0') {
         qdict_set_default_str(options, "user", iscsi_url->user);
         qdict_set_default_str(options, "password", iscsi_url->passwd);
     }
 
     iscsi_destroy_url(iscsi_url);
 }
 
 static QemuOptsList runtime_opts = {
     .name = "iscsi",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
     .desc = {
         {
             .name = "transport",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "portal",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "target",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "user",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "password",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "password-secret",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "lun",
             .type = QEMU_OPT_NUMBER,
         },
         {
             .name = "initiator-name",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "header-digest",
             .type = QEMU_OPT_STRING,
         },
         {
             .name = "timeout",
             .type = QEMU_OPT_NUMBER,
         },
         { /* end of list */ }
     },
 };
 
 static void iscsi_save_designator(IscsiLun *lun,
                                   struct scsi_inquiry_device_identification *inq_di)
 {
     struct scsi_inquiry_device_designator *desig, *copy = NULL;
 
     for (desig = inq_di->designators; desig; desig = desig->next) {
         if (desig->association ||
             desig->designator_type > SCSI_DESIGNATOR_TYPE_NAA) {
             continue;
         }
         /* NAA works better than T10 vendor ID based designator. */
         if (!copy || copy->designator_type < desig->designator_type) {
             copy = desig;
         }
     }
     if (copy) {
         lun->dd = g_new(struct scsi_inquiry_device_designator, 1);
         *lun->dd = *copy;
         lun->dd->next = NULL;
         lun->dd->designator = g_malloc(copy->designator_length);
         memcpy(lun->dd->designator, copy->designator, copy->designator_length);
     }
 }
 
 static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
                       Error **errp)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct iscsi_context *iscsi = NULL;
     struct scsi_task *task = NULL;
     struct scsi_inquiry_standard *inq = NULL;
     struct scsi_inquiry_supported_pages *inq_vpd;
     char *initiator_name = NULL;
     QemuOpts *opts;
     Error *local_err = NULL;
     const char *transport_name, *portal, *target;
 #if LIBISCSI_API_VERSION >= (20160603)
     enum iscsi_transport_type transport;
 #endif
     int i, ret = 0, timeout = 0, lun;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
         ret = -EINVAL;
         goto out;
     }
 
     transport_name = qemu_opt_get(opts, "transport");
     portal = qemu_opt_get(opts, "portal");
     target = qemu_opt_get(opts, "target");
     lun = qemu_opt_get_number(opts, "lun", 0);
 
     if (!transport_name || !portal || !target) {
         error_setg(errp, "Need all of transport, portal and target options");
         ret = -EINVAL;
         goto out;
     }
 
     if (!strcmp(transport_name, "tcp")) {
 #if LIBISCSI_API_VERSION >= (20160603)
         transport = TCP_TRANSPORT;
     } else if (!strcmp(transport_name, "iser")) {
         transport = ISER_TRANSPORT;
 #else
         /* TCP is what older libiscsi versions always use */
 #endif
     } else {
         error_setg(errp, "Unknown transport: %s", transport_name);
         ret = -EINVAL;
         goto out;
     }
 
     memset(iscsilun, 0, sizeof(IscsiLun));
 
     initiator_name = get_initiator_name(opts);
 
     iscsi = iscsi_create_context(initiator_name);
     if (iscsi == NULL) {
         error_setg(errp, "iSCSI: Failed to create iSCSI context.");
         ret = -ENOMEM;
         goto out;
     }
 #if LIBISCSI_API_VERSION >= (20160603)
     if (iscsi_init_transport(iscsi, transport)) {
         error_setg(errp, ("Error initializing transport."));
         ret = -EINVAL;
         goto out;
     }
 #endif
     if (iscsi_set_targetname(iscsi, target)) {
         error_setg(errp, "iSCSI: Failed to set target name.");
         ret = -EINVAL;
         goto out;
     }
 
     /* check if we got CHAP username/password via the options */
     apply_chap(iscsi, opts, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
         goto out;
     }
 
     if (iscsi_set_session_type(iscsi, ISCSI_SESSION_NORMAL) != 0) {
         error_setg(errp, "iSCSI: Failed to set session type to normal.");
         ret = -EINVAL;
         goto out;
     }
 
     /* check if we got HEADER_DIGEST via the options */
     apply_header_digest(iscsi, opts, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
         goto out;
     }
 
     /* timeout handling is broken in libiscsi before 1.15.0 */
     timeout = qemu_opt_get_number(opts, "timeout", 0);
 #if LIBISCSI_API_VERSION >= 20150621
     iscsi_set_timeout(iscsi, timeout);
 #else
     if (timeout) {
         warn_report("iSCSI: ignoring timeout value for libiscsi <1.15.0");
     }
 #endif
 
     if (iscsi_full_connect_sync(iscsi, portal, lun) != 0) {
         error_setg(errp, "iSCSI: Failed to connect to LUN : %s",
             iscsi_get_error(iscsi));
         ret = -EINVAL;
         goto out;
     }
 
     iscsilun->iscsi = iscsi;
     iscsilun->aio_context = bdrv_get_aio_context(bs);
     iscsilun->lun = lun;
     iscsilun->has_write_same = true;
 
     task = iscsi_do_inquiry(iscsilun->iscsi, iscsilun->lun, 0, 0,
                             (void **) &inq, errp);
     if (task == NULL) {
         ret = -EINVAL;
         goto out;
     }
     iscsilun->type = inq->periperal_device_type;
     scsi_free_scsi_task(task);
     task = NULL;
 
     iscsi_modesense_sync(iscsilun);
     if (iscsilun->dpofua) {
         bs->supported_write_flags = BDRV_REQ_FUA;
     }
 
     /* Check the write protect flag of the LUN if we want to write */
     if (iscsilun->type == TYPE_DISK && (flags & BDRV_O_RDWR) &&
         iscsilun->write_protected) {
         ret = bdrv_apply_auto_read_only(bs, "LUN is write protected", errp);
         if (ret < 0) {
             goto out;
         }
         flags &= ~BDRV_O_RDWR;
     }
 
     iscsi_readcapacity_sync(iscsilun, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
         goto out;
     }
     bs->total_sectors = sector_lun2qemu(iscsilun->num_blocks, iscsilun);
 
     /* We don't have any emulation for devices other than disks and CD-ROMs, so
      * this must be sg ioctl compatible. We force it to be sg, otherwise qemu
      * will try to read from the device to guess the image format.
      */
     if (iscsilun->type != TYPE_DISK && iscsilun->type != TYPE_ROM) {
         bs->sg = true;
     }
 
     task = iscsi_do_inquiry(iscsilun->iscsi, iscsilun->lun, 1,
                             SCSI_INQUIRY_PAGECODE_SUPPORTED_VPD_PAGES,
                             (void **) &inq_vpd, errp);
     if (task == NULL) {
         ret = -EINVAL;
         goto out;
     }
     for (i = 0; i < inq_vpd->num_pages; i++) {
         struct scsi_task *inq_task;
         struct scsi_inquiry_logical_block_provisioning *inq_lbp;
         struct scsi_inquiry_block_limits *inq_bl;
         struct scsi_inquiry_device_identification *inq_di;
         switch (inq_vpd->pages[i]) {
         case SCSI_INQUIRY_PAGECODE_LOGICAL_BLOCK_PROVISIONING:
             inq_task = iscsi_do_inquiry(iscsilun->iscsi, iscsilun->lun, 1,
                                         SCSI_INQUIRY_PAGECODE_LOGICAL_BLOCK_PROVISIONING,
                                         (void **) &inq_lbp, errp);
             if (inq_task == NULL) {
                 ret = -EINVAL;
                 goto out;
             }
             memcpy(&iscsilun->lbp, inq_lbp,
                    sizeof(struct scsi_inquiry_logical_block_provisioning));
             scsi_free_scsi_task(inq_task);
             break;
         case SCSI_INQUIRY_PAGECODE_BLOCK_LIMITS:
             inq_task = iscsi_do_inquiry(iscsilun->iscsi, iscsilun->lun, 1,
                                     SCSI_INQUIRY_PAGECODE_BLOCK_LIMITS,
                                     (void **) &inq_bl, errp);
             if (inq_task == NULL) {
                 ret = -EINVAL;
                 goto out;
             }
             memcpy(&iscsilun->bl, inq_bl,
                    sizeof(struct scsi_inquiry_block_limits));
             scsi_free_scsi_task(inq_task);
             break;
         case SCSI_INQUIRY_PAGECODE_DEVICE_IDENTIFICATION:
             inq_task = iscsi_do_inquiry(iscsilun->iscsi, iscsilun->lun, 1,
                                     SCSI_INQUIRY_PAGECODE_DEVICE_IDENTIFICATION,
                                     (void **) &inq_di, errp);
             if (inq_task == NULL) {
                 ret = -EINVAL;
                 goto out;
             }
             iscsi_save_designator(iscsilun, inq_di);
             scsi_free_scsi_task(inq_task);
             break;
         default:
             break;
         }
     }
     scsi_free_scsi_task(task);
     task = NULL;
 
     qemu_mutex_init(&iscsilun->mutex);
     iscsi_attach_aio_context(bs, iscsilun->aio_context);
 
     /* Guess the internal cluster (page) size of the iscsi target by the means
      * of opt_unmap_gran. Transfer the unmap granularity only if it has a
      * reasonable size */
     if (iscsilun->bl.opt_unmap_gran * iscsilun->block_size >= 4 * 1024 &&
         iscsilun->bl.opt_unmap_gran * iscsilun->block_size <= 16 * 1024 * 1024) {
         iscsilun->cluster_size = iscsilun->bl.opt_unmap_gran *
             iscsilun->block_size;
         if (iscsilun->lbprz) {
             ret = iscsi_allocmap_init(iscsilun, flags);
         }
     }
 
     if (iscsilun->lbprz && iscsilun->lbp.lbpws) {
         bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
     }
 
 out:
     qemu_opts_del(opts);
     g_free(initiator_name);
     if (task != NULL) {
         scsi_free_scsi_task(task);
     }
 
     if (ret) {
         if (iscsi != NULL) {
             if (iscsi_is_logged_in(iscsi)) {
                 iscsi_logout_sync(iscsi);
             }
             iscsi_destroy_context(iscsi);
         }
         memset(iscsilun, 0, sizeof(IscsiLun));
     }
 
     return ret;
 }
 
 static void iscsi_close(BlockDriverState *bs)
 {
     IscsiLun *iscsilun = bs->opaque;
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
     iscsi_detach_aio_context(bs);
     if (iscsi_is_logged_in(iscsi)) {
         iscsi_logout_sync(iscsi);
     }
     iscsi_destroy_context(iscsi);
     if (iscsilun->dd) {
         g_free(iscsilun->dd->designator);
         g_free(iscsilun->dd);
     }
     g_free(iscsilun->zeroblock);
     iscsi_allocmap_free(iscsilun);
     qemu_mutex_destroy(&iscsilun->mutex);
     memset(iscsilun, 0, sizeof(IscsiLun));
 }
 
 static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
 {
     /* We don't actually refresh here, but just return data queried in
      * iscsi_open(): iscsi targets don't change their limits. */
 
     IscsiLun *iscsilun = bs->opaque;
     uint64_t max_xfer_len = iscsilun->use_16_for_rw ? 0xffffffff : 0xffff;
     unsigned int block_size = MAX(BDRV_SECTOR_SIZE, iscsilun->block_size);
 
     assert(iscsilun->block_size >= BDRV_SECTOR_SIZE || bdrv_is_sg(bs));
 
     bs->bl.request_alignment = block_size;
 
     if (iscsilun->bl.max_xfer_len) {
         max_xfer_len = MIN(max_xfer_len, iscsilun->bl.max_xfer_len);
     }
 
     if (max_xfer_len * block_size < INT_MAX) {
         bs->bl.max_transfer = max_xfer_len * iscsilun->block_size;
     }
 
     if (iscsilun->lbp.lbpu) {
         bs->bl.max_pdiscard =
             MIN_NON_ZERO(iscsilun->bl.max_unmap * iscsilun->block_size,
                          (uint64_t)UINT32_MAX * iscsilun->block_size);
         bs->bl.pdiscard_alignment =
             iscsilun->bl.opt_unmap_gran * iscsilun->block_size;
     } else {
         bs->bl.pdiscard_alignment = iscsilun->block_size;
     }
 
     bs->bl.max_pwrite_zeroes =
         MIN_NON_ZERO(iscsilun->bl.max_ws_len * iscsilun->block_size,
                      max_xfer_len * iscsilun->block_size);
 
     if (iscsilun->lbp.lbpws) {
         bs->bl.pwrite_zeroes_alignment =
             iscsilun->bl.opt_unmap_gran * iscsilun->block_size;
     } else {
         bs->bl.pwrite_zeroes_alignment = iscsilun->block_size;
     }
     if (iscsilun->bl.opt_xfer_len &&
         iscsilun->bl.opt_xfer_len < INT_MAX / block_size) {
         bs->bl.opt_transfer = pow2floor(iscsilun->bl.opt_xfer_len *
                                         iscsilun->block_size);
     }
 }
 
 /* Note that this will not re-establish a connection with an iSCSI target - it
  * is effectively a NOP.  */
 static int iscsi_reopen_prepare(BDRVReopenState *state,
                                 BlockReopenQueue *queue, Error **errp)
 {
     IscsiLun *iscsilun = state->bs->opaque;
 
     if (state->flags & BDRV_O_RDWR && iscsilun->write_protected) {
         error_setg(errp, "Cannot open a write protected LUN as read-write");
         return -EACCES;
     }
     return 0;
 }
 
 static void iscsi_reopen_commit(BDRVReopenState *reopen_state)
 {
     IscsiLun *iscsilun = reopen_state->bs->opaque;
 
     /* the cache.direct status might have changed */
     if (iscsilun->allocmap != NULL) {
         iscsi_allocmap_init(iscsilun, reopen_state->flags);
     }
 }
 
 static int coroutine_fn iscsi_co_truncate(BlockDriverState *bs, int64_t offset,
                                           bool exact, PreallocMode prealloc,
                                           BdrvRequestFlags flags, Error **errp)
 {
     IscsiLun *iscsilun = bs->opaque;
     int64_t cur_length;
     Error *local_err = NULL;
 
     if (prealloc != PREALLOC_MODE_OFF) {
         error_setg(errp, "Unsupported preallocation mode '%s'",
                    PreallocMode_str(prealloc));
         return -ENOTSUP;
     }
 
     if (iscsilun->type != TYPE_DISK) {
         error_setg(errp, "Cannot resize non-disk iSCSI devices");
         return -ENOTSUP;
     }
 
     iscsi_readcapacity_sync(iscsilun, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         return -EIO;
     }
 
     cur_length = iscsi_getlength(bs);
     if (offset != cur_length && exact) {
         error_setg(errp, "Cannot resize iSCSI devices");
         return -ENOTSUP;
     } else if (offset > cur_length) {
         error_setg(errp, "Cannot grow iSCSI devices");
         return -EINVAL;
     }
 
     if (iscsilun->allocmap != NULL) {
         iscsi_allocmap_init(iscsilun, bs->open_flags);
     }
 
     return 0;
 }
 
 static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     IscsiLun *iscsilun = bs->opaque;
     bdi->cluster_size = iscsilun->cluster_size;
     return 0;
 }
 
 static void coroutine_fn iscsi_co_invalidate_cache(BlockDriverState *bs,
                                                    Error **errp)
 {
     IscsiLun *iscsilun = bs->opaque;
     iscsi_allocmap_invalidate(iscsilun);
 }
 
 static int coroutine_fn iscsi_co_copy_range_from(BlockDriverState *bs,
                                                  BdrvChild *src,
                                                  int64_t src_offset,
                                                  BdrvChild *dst,
                                                  int64_t dst_offset,
                                                  int64_t bytes,
                                                  BdrvRequestFlags read_flags,
                                                  BdrvRequestFlags write_flags)
 {
     return bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes,
                                  read_flags, write_flags);
 }
 
 static struct scsi_task *iscsi_xcopy_task(int param_len)
 {
     struct scsi_task *task;
 
     task = g_new0(struct scsi_task, 1);
 
     task->cdb[0]     = EXTENDED_COPY;
     task->cdb[10]    = (param_len >> 24) & 0xFF;
     task->cdb[11]    = (param_len >> 16) & 0xFF;
     task->cdb[12]    = (param_len >> 8) & 0xFF;
     task->cdb[13]    = param_len & 0xFF;
     task->cdb_size   = 16;
     task->xfer_dir   = SCSI_XFER_WRITE;
     task->expxferlen = param_len;
 
     return task;
 }
 
 static void iscsi_populate_target_desc(unsigned char *desc, IscsiLun *lun)
 {
     struct scsi_inquiry_device_designator *dd = lun->dd;
 
     memset(desc, 0, 32);
     desc[0] = 0xE4; /* IDENT_DESCR_TGT_DESCR */
     desc[4] = dd->code_set;
     desc[5] = (dd->designator_type & 0xF)
         | ((dd->association & 3) << 4);
     desc[7] = dd->designator_length;
     memcpy(desc + 8, dd->designator, MIN(dd->designator_length, 20));
 
     desc[28] = 0;
     desc[29] = (lun->block_size >> 16) & 0xFF;
     desc[30] = (lun->block_size >> 8) & 0xFF;
     desc[31] = lun->block_size & 0xFF;
 }
 
 static void iscsi_xcopy_desc_hdr(uint8_t *hdr, int dc, int cat, int src_index,
                                  int dst_index)
 {
     hdr[0] = 0x02; /* BLK_TO_BLK_SEG_DESCR */
     hdr[1] = ((dc << 1) | cat) & 0xFF;
     hdr[2] = (XCOPY_BLK2BLK_SEG_DESC_SIZE >> 8) & 0xFF;
     /* don't account for the first 4 bytes in descriptor header*/
     hdr[3] = (XCOPY_BLK2BLK_SEG_DESC_SIZE - 4 /* SEG_DESC_SRC_INDEX_OFFSET */) & 0xFF;
     hdr[4] = (src_index >> 8) & 0xFF;
     hdr[5] = src_index & 0xFF;
     hdr[6] = (dst_index >> 8) & 0xFF;
     hdr[7] = dst_index & 0xFF;
 }
 
 static void iscsi_xcopy_populate_desc(uint8_t *desc, int dc, int cat,
                                       int src_index, int dst_index, int num_blks,
                                       uint64_t src_lba, uint64_t dst_lba)
 {
     iscsi_xcopy_desc_hdr(desc, dc, cat, src_index, dst_index);
 
     /* The caller should verify the request size */
     assert(num_blks < 65536);
     desc[10] = (num_blks >> 8) & 0xFF;
     desc[11] = num_blks & 0xFF;
     desc[12] = (src_lba >> 56) & 0xFF;
     desc[13] = (src_lba >> 48) & 0xFF;
     desc[14] = (src_lba >> 40) & 0xFF;
     desc[15] = (src_lba >> 32) & 0xFF;
     desc[16] = (src_lba >> 24) & 0xFF;
     desc[17] = (src_lba >> 16) & 0xFF;
     desc[18] = (src_lba >> 8) & 0xFF;
     desc[19] = src_lba & 0xFF;
     desc[20] = (dst_lba >> 56) & 0xFF;
     desc[21] = (dst_lba >> 48) & 0xFF;
     desc[22] = (dst_lba >> 40) & 0xFF;
     desc[23] = (dst_lba >> 32) & 0xFF;
     desc[24] = (dst_lba >> 24) & 0xFF;
     desc[25] = (dst_lba >> 16) & 0xFF;
     desc[26] = (dst_lba >> 8) & 0xFF;
     desc[27] = dst_lba & 0xFF;
 }
 
 static void iscsi_xcopy_populate_header(unsigned char *buf, int list_id, int str,
                                         int list_id_usage, int prio,
                                         int tgt_desc_len,
                                         int seg_desc_len, int inline_data_len)
 {
     buf[0] = list_id;
     buf[1] = ((str & 1) << 5) | ((list_id_usage & 3) << 3) | (prio & 7);
     buf[2] = (tgt_desc_len >> 8) & 0xFF;
     buf[3] = tgt_desc_len & 0xFF;
     buf[8] = (seg_desc_len >> 24) & 0xFF;
     buf[9] = (seg_desc_len >> 16) & 0xFF;
     buf[10] = (seg_desc_len >> 8) & 0xFF;
     buf[11] = seg_desc_len & 0xFF;
     buf[12] = (inline_data_len >> 24) & 0xFF;
     buf[13] = (inline_data_len >> 16) & 0xFF;
     buf[14] = (inline_data_len >> 8) & 0xFF;
     buf[15] = inline_data_len & 0xFF;
 }
 
 static void iscsi_xcopy_data(struct iscsi_data *data,
                              IscsiLun *src, int64_t src_lba,
                              IscsiLun *dst, int64_t dst_lba,
                              uint16_t num_blocks)
 {
     uint8_t *buf;
     const int src_offset = XCOPY_DESC_OFFSET;
     const int dst_offset = XCOPY_DESC_OFFSET + IDENT_DESCR_TGT_DESCR_SIZE;
     const int seg_offset = dst_offset + IDENT_DESCR_TGT_DESCR_SIZE;
 
     data->size = XCOPY_DESC_OFFSET +
                  IDENT_DESCR_TGT_DESCR_SIZE * 2 +
                  XCOPY_BLK2BLK_SEG_DESC_SIZE;
     data->data = g_malloc0(data->size);
     buf = data->data;
 
     /* Initialise the parameter list header */
     iscsi_xcopy_populate_header(buf, 1, 0, 2 /* LIST_ID_USAGE_DISCARD */,
                                 0, 2 * IDENT_DESCR_TGT_DESCR_SIZE,
                                 XCOPY_BLK2BLK_SEG_DESC_SIZE,
                                 0);
 
     /* Initialise CSCD list with one src + one dst descriptor */
     iscsi_populate_target_desc(&buf[src_offset], src);
     iscsi_populate_target_desc(&buf[dst_offset], dst);
 
     /* Initialise one segment descriptor */
     iscsi_xcopy_populate_desc(&buf[seg_offset], 0, 0, 0, 1, num_blocks,
                               src_lba, dst_lba);
 }
 
 static int coroutine_fn iscsi_co_copy_range_to(BlockDriverState *bs,
                                                BdrvChild *src,
                                                int64_t src_offset,
                                                BdrvChild *dst,
                                                int64_t dst_offset,
                                                int64_t bytes,
                                                BdrvRequestFlags read_flags,
                                                BdrvRequestFlags write_flags)
 {
     IscsiLun *dst_lun = dst->bs->opaque;
     IscsiLun *src_lun;
     struct IscsiTask iscsi_task;
     struct iscsi_data data;
     int r = 0;
     int block_size;
 
     if (src->bs->drv->bdrv_co_copy_range_to != iscsi_co_copy_range_to) {
         return -ENOTSUP;
     }
     src_lun = src->bs->opaque;
 
     if (!src_lun->dd || !dst_lun->dd) {
         return -ENOTSUP;
     }
     if (!is_byte_request_lun_aligned(dst_offset, bytes, dst_lun)) {
         return -ENOTSUP;
     }
     if (!is_byte_request_lun_aligned(src_offset, bytes, src_lun)) {
         return -ENOTSUP;
     }
     if (dst_lun->block_size != src_lun->block_size ||
         !dst_lun->block_size) {
         return -ENOTSUP;
     }
 
     block_size = dst_lun->block_size;
     if (bytes / block_size > 65535) {
         return -ENOTSUP;
     }
 
     iscsi_xcopy_data(&data,
                      src_lun, src_offset / block_size,
                      dst_lun, dst_offset / block_size,
                      bytes / block_size);
 
     iscsi_co_init_iscsitask(dst_lun, &iscsi_task);
 
     qemu_mutex_lock(&dst_lun->mutex);
     iscsi_task.task = iscsi_xcopy_task(data.size);
 retry:
     if (iscsi_scsi_command_async(dst_lun->iscsi, dst_lun->lun,
                                  iscsi_task.task, iscsi_co_generic_cb,
                                  &data,
                                  &iscsi_task) != 0) {
         r = -EIO;
         goto out_unlock;
     }
 
     iscsi_co_wait_for_task(&iscsi_task, dst_lun);
 
     if (iscsi_task.do_retry) {
         iscsi_task.complete = 0;
         goto retry;
     }
 
     if (iscsi_task.status != SCSI_STATUS_GOOD) {
         r = iscsi_task.err_code;
         goto out_unlock;
     }
 
 out_unlock:
 
     trace_iscsi_xcopy(src_lun, src_offset, dst_lun, dst_offset, bytes, r);
     g_free(iscsi_task.task);
     qemu_mutex_unlock(&dst_lun->mutex);
     g_free(iscsi_task.err_str);
     return r;
 }
 
 
 static const char *const iscsi_strong_runtime_opts[] = {
     "transport",
     "portal",
     "target",
     "user",
     "password",
     "password-secret",
     "lun",
     "initiator-name",
     "header-digest",
 
     NULL
 };
 
 static BlockDriver bdrv_iscsi = {
     .format_name     = "iscsi",
     .protocol_name   = "iscsi",
 
     .instance_size          = sizeof(IscsiLun),
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
     .bdrv_co_create_opts    = bdrv_co_create_opts_simple,
     .create_opts            = &bdrv_create_opts_simple,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache = iscsi_co_invalidate_cache,
 
     .bdrv_getlength  = iscsi_getlength,
     .bdrv_get_info   = iscsi_get_info,
     .bdrv_co_truncate    = iscsi_co_truncate,
     .bdrv_refresh_limits = iscsi_refresh_limits,
 
     .bdrv_co_block_status  = iscsi_co_block_status,
     .bdrv_co_pdiscard      = iscsi_co_pdiscard,
     .bdrv_co_copy_range_from = iscsi_co_copy_range_from,
     .bdrv_co_copy_range_to  = iscsi_co_copy_range_to,
     .bdrv_co_pwrite_zeroes = iscsi_co_pwrite_zeroes,
     .bdrv_co_readv         = iscsi_co_readv,
     .bdrv_co_writev        = iscsi_co_writev,
     .bdrv_co_flush_to_disk = iscsi_co_flush,
 
 #ifdef __linux__
     .bdrv_aio_ioctl   = iscsi_aio_ioctl,
 #endif
 
     .bdrv_detach_aio_context = iscsi_detach_aio_context,
     .bdrv_attach_aio_context = iscsi_attach_aio_context,
 
     .strong_runtime_opts = iscsi_strong_runtime_opts,
 };
 
 #if LIBISCSI_API_VERSION >= (20160603)
 static BlockDriver bdrv_iser = {
     .format_name     = "iser",
     .protocol_name   = "iser",
 
     .instance_size          = sizeof(IscsiLun),
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
     .bdrv_co_create_opts    = bdrv_co_create_opts_simple,
     .create_opts            = &bdrv_create_opts_simple,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache  = iscsi_co_invalidate_cache,
 
     .bdrv_getlength  = iscsi_getlength,
     .bdrv_get_info   = iscsi_get_info,
     .bdrv_co_truncate    = iscsi_co_truncate,
     .bdrv_refresh_limits = iscsi_refresh_limits,
 
     .bdrv_co_block_status  = iscsi_co_block_status,
     .bdrv_co_pdiscard      = iscsi_co_pdiscard,
     .bdrv_co_copy_range_from = iscsi_co_copy_range_from,
     .bdrv_co_copy_range_to  = iscsi_co_copy_range_to,
     .bdrv_co_pwrite_zeroes = iscsi_co_pwrite_zeroes,
     .bdrv_co_readv         = iscsi_co_readv,
     .bdrv_co_writev        = iscsi_co_writev,
     .bdrv_co_flush_to_disk = iscsi_co_flush,
 
 #ifdef __linux__
     .bdrv_aio_ioctl   = iscsi_aio_ioctl,
 #endif
 
     .bdrv_detach_aio_context = iscsi_detach_aio_context,
     .bdrv_attach_aio_context = iscsi_attach_aio_context,
 
     .strong_runtime_opts = iscsi_strong_runtime_opts,
 };
 #endif
 
 static void iscsi_block_init(void)
 {
     bdrv_register(&bdrv_iscsi);
 #if LIBISCSI_API_VERSION >= (20160603)
     bdrv_register(&bdrv_iser);
 #endif
 }
 
 block_init(iscsi_block_init);