diff mbox series

[v8,10/10] block/iscsi: add persistent reservation in/out driver

Message ID 20240709024706.4108-11-luchangqi.123@bytedance.com (mailing list archive)
State New, archived
Headers show
Series Support persistent reservation operations | expand

Commit Message

Changqi Lu July 9, 2024, 2:47 a.m. UTC 
Add persistent reservation in/out operations for iscsi driver.
The following methods are implemented: bdrv_co_pr_read_keys,
bdrv_co_pr_read_reservation, bdrv_co_pr_register, bdrv_co_pr_reserve,
bdrv_co_pr_release, bdrv_co_pr_clear and bdrv_co_pr_preempt.

Signed-off-by: Changqi Lu <luchangqi.123@bytedance.com>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
 block/iscsi.c | 425 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 425 insertions(+)

Comments

Stefan Hajnoczi July 11, 2024, 1:04 p.m. UTC | #1 
On Tue, Jul 09, 2024 at 10:47:06AM +0800, Changqi Lu wrote:
> Add persistent reservation in/out operations for iscsi driver.
> The following methods are implemented: bdrv_co_pr_read_keys,
> bdrv_co_pr_read_reservation, bdrv_co_pr_register, bdrv_co_pr_reserve,
> bdrv_co_pr_release, bdrv_co_pr_clear and bdrv_co_pr_preempt.
> 
> Signed-off-by: Changqi Lu <luchangqi.123@bytedance.com>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
>  block/iscsi.c | 425 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 425 insertions(+)
> 
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 2ff14b7472..ba51f6d016 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -96,6 +96,7 @@ typedef struct IscsiLun {
>      unsigned long *allocmap_valid;
>      long allocmap_size;
>      int cluster_size;
> +    uint8_t pr_cap;
>      bool use_16_for_rw;
>      bool write_protected;
>      bool lbpme;
> @@ -280,6 +281,10 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
>                      iTask->err_code = -error;
>                      iTask->err_str = g_strdup(iscsi_get_error(iscsi));
>                  }
> +            } else if (status == SCSI_STATUS_RESERVATION_CONFLICT) {
> +                iTask->err_code = -EBADE;
> +                error_report("iSCSI Persistent Reservation Conflict: %s",
> +                             iscsi_get_error(iscsi));
>              }
>          }
>      }
> @@ -1792,6 +1797,50 @@ static void iscsi_save_designator(IscsiLun *lun,
>      }
>  }
>  
> +/*
> + *  Ensure iscsi_open() must succeed, weather or not the target
> + *  implement SCSI_PR_IN_REPORT_CAPABILITIES.
> + */
> +static void iscsi_get_pr_cap_sync(IscsiLun *iscsilun)
> +{
> +    struct scsi_task *task = NULL;
> +    struct scsi_persistent_reserve_in_report_capabilities *rc = NULL;
> +    int retries = ISCSI_CMD_RETRIES;
> +    int xferlen = sizeof(struct scsi_persistent_reserve_in_report_capabilities);
> +
> +    do {
> +        if (task != NULL) {
> +            scsi_free_scsi_task(task);
> +            task = NULL;
> +        }
> +
> +        task = iscsi_persistent_reserve_in_sync(iscsilun->iscsi,
> +               iscsilun->lun, SCSI_PR_IN_REPORT_CAPABILITIES, xferlen);
> +        if (task != NULL && task->status == SCSI_STATUS_GOOD) {
> +                rc = scsi_datain_unmarshall(task);
> +                if (rc == NULL) {
> +                    error_report("iSCSI: Failed to unmarshall "
> +                                 "report capabilities data.");
> +                } else {
> +                    iscsilun->pr_cap =
> +                    scsi_pr_cap_to_block(rc->persistent_reservation_type_mask);
> +                    iscsilun->pr_cap |= (rc->ptpl_a) ? BLK_PR_CAP_PTPL : 0;
> +                }
> +                break;
> +        }
> +    } 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_report("iSCSI: failed to send report capabilities command.");
> +    }
> +
> +    if (task) {
> +        scsi_free_scsi_task(task);
> +    }
> +}
> +
>  static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
>                        Error **errp)
>  {
> @@ -2024,6 +2073,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
>          bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
>      }
>  
> +    iscsi_get_pr_cap_sync(iscsilun);
>  out:
>      qemu_opts_del(opts);
>      g_free(initiator_name);
> @@ -2110,6 +2160,8 @@ static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
>          bs->bl.opt_transfer = pow2floor(iscsilun->bl.opt_xfer_len *
>                                          iscsilun->block_size);
>      }
> +
> +    bs->bl.pr_cap = iscsilun->pr_cap;
>  }
>  
>  /* Note that this will not re-establish a connection with an iSCSI target - it
> @@ -2408,6 +2460,371 @@ out_unlock:
>      return r;
>  }
>  
> +static int coroutine_fn
> +iscsi_co_pr_read_keys(BlockDriverState *bs, uint32_t *generation,
> +                      uint32_t num_keys, uint64_t *keys)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    QEMUIOVector qiov;
> +    struct IscsiTask iTask;
> +    int xferlen = sizeof(struct scsi_persistent_reserve_in_read_keys) +
> +                  sizeof(uint64_t) * num_keys;
> +    g_autofree uint8_t *buf = g_malloc0(xferlen);
> +    int32_t num_collect_keys = 0;
> +    int r = 0;
> +
> +    qemu_iovec_init_buf(&qiov, buf, xferlen);
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_in_task(iscsilun->iscsi,
> +                 iscsilun->lun, SCSI_PR_IN_READ_KEYS, xferlen,
> +                 iscsi_co_generic_cb, &iTask);
> +
> +    if (iTask.task == NULL) {
> +        qemu_mutex_unlock(&iscsilun->mutex);
> +        return -ENOMEM;
> +    }
> +
> +    scsi_task_set_iov_in(iTask.task, (struct scsi_iovec *)qiov.iov, qiov.niov);
> +    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 PERSISTENT_RESERVE_IN failed: %s", iTask.err_str);
> +        r = iTask.err_code;
> +        goto out;
> +    }
> +
> +    memcpy(generation, &buf[0], 4);
> +    *generation = be32_to_cpu(*generation);
> +    memcpy(&num_collect_keys, &buf[4], 4);
> +    num_collect_keys = be32_to_cpu(num_collect_keys) / sizeof(uint64_t);
> +    if (num_collect_keys > num_keys) {
> +        r = -EINVAL;
> +        goto out;
> +    }
> +
> +    for (int i = 0; i < num_collect_keys; i++) {
> +        memcpy(&keys[i], &buf[8 + i * 8], 8);
> +        keys[i] = be64_to_cpu(keys[i]);
> +    }
> +    r = num_collect_keys;
> +
> +out:
> +    qemu_mutex_unlock(&iscsilun->mutex);
> +    g_free(iTask.err_str);
> +    g_free(buf);

buf is declared g_autofree, so this explicit g_free() call causes a
double-free. There is no need to call g_free().

> +    return r;
> +}
> +
> +static int coroutine_fn
> +iscsi_co_pr_read_reservation(BlockDriverState *bs, uint32_t *generation,
> +                             uint64_t *key, BlockPrType *type)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    QEMUIOVector qiov;
> +    struct IscsiTask iTask;
> +    int xferlen = sizeof(struct scsi_persistent_reserve_in_read_reservation);
> +    g_autofree uint8_t *buf = g_malloc0(xferlen);
> +    uint8_t scope_type = 0;
> +    int32_t num_collect_keys = 0;
> +    int r = 0;
> +
> +    qemu_iovec_init_buf(&qiov, buf, xferlen);
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_in_task(iscsilun->iscsi,
> +                 iscsilun->lun, SCSI_PR_IN_READ_RESERVATION,
> +                 xferlen, iscsi_co_generic_cb, &iTask);
> +
> +    if (iTask.task == NULL) {
> +        qemu_mutex_unlock(&iscsilun->mutex);
> +        return -ENOMEM;
> +    }
> +
> +    scsi_task_set_iov_in(iTask.task, (struct scsi_iovec *)qiov.iov, qiov.niov);
> +    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 PERSISTENT_RESERVE_IN failed: %s", iTask.err_str);
> +        r = iTask.err_code;
> +        goto out;
> +    }
> +
> +    memcpy(generation, &buf[0], 4);
> +    *generation = be32_to_cpu(*generation);
> +    memcpy(key, &buf[8], 8);
> +    *key = be64_to_cpu(*key);
> +    memcpy(&scope_type, &buf[21], 1);
> +    *type = scsi_pr_type_to_block(scope_type & 0xf);
> +    memcpy(&num_collect_keys, &buf[4], 4);
> +    r = be32_to_cpu(num_collect_keys) / sizeof(uint64_t);
> +out:
> +    qemu_mutex_unlock(&iscsilun->mutex);
> +    g_free(iTask.err_str);
> +    g_free(buf);

Double-free. This line can be removed.

> +    return r;
> +}
> +
> +static int coroutine_fn
> +iscsi_co_pr_register(BlockDriverState *bs, uint64_t old_key,
> +                     uint64_t new_key, BlockPrType type,
> +                     bool ptpl, bool ignore_key)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct scsi_persistent_reserve_out_basic basic;
> +    SCSIPrOutAction action = ignore_key ? SCSI_PR_OUT_REG_AND_IGNORE_KEY :
> +                                          SCSI_PR_OUT_REGISTER;
> +    int r = 0;
> +
> +    basic.reservation_key = old_key;
> +    basic.service_action_reservation_key = new_key;
> +    basic.aptpl = ptpl ? 1 : 0;
> +
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
> +                 iscsilun->lun, action, 0, block_pr_type_to_scsi(type),
> +                 &basic, 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_reserve(BlockDriverState *bs, uint64_t key, BlockPrType type)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct scsi_persistent_reserve_out_basic basic;
> +    int r = 0;
> +
> +    basic.reservation_key = key;
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
> +                 iscsilun->lun, SCSI_PR_OUT_RESERVE, 0,
> +                 block_pr_type_to_scsi(type), &basic,
> +                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_release(BlockDriverState *bs, uint64_t key, BlockPrType type)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct scsi_persistent_reserve_out_basic basic;
> +    int r = 0;
> +
> +    basic.reservation_key = key;
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
> +                 iscsilun->lun, SCSI_PR_OUT_RELEASE, 0,
> +                 block_pr_type_to_scsi(type), &basic,
> +                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_clear(BlockDriverState *bs, uint64_t key)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct scsi_persistent_reserve_out_basic basic;
> +    int r = 0;
> +
> +    basic.reservation_key = key;
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
> +                 iscsilun->lun, SCSI_PR_OUT_CLEAR, 0, 0, &basic,
> +                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_preempt(BlockDriverState *bs, uint64_t old_key,
> +                    uint64_t new_key, BlockPrType type, bool abort)
> +{
> +    IscsiLun *iscsilun = bs->opaque;
> +    struct IscsiTask iTask;
> +    struct scsi_persistent_reserve_out_basic basic;
> +    SCSIPrOutAction action = abort ? SCSI_PR_OUT_PREEMPT_AND_ABORT :
> +                                     SCSI_PR_OUT_PREEMPT;
> +    int r = 0;
> +
> +    basic.reservation_key = old_key;
> +    basic.service_action_reservation_key = new_key;
> +
> +    iscsi_co_init_iscsitask(iscsilun, &iTask);
> +    qemu_mutex_lock(&iscsilun->mutex);
> +retry:
> +    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
> +                 iscsilun->lun, action, 0, block_pr_type_to_scsi(type),
> +                 &basic, 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.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 PERSISTENT_RESERVE_OUT failed: %s", iTask.err_str);
> +        r = iTask.err_code;
> +    }
> +
> +    qemu_mutex_unlock(&iscsilun->mutex);
> +
> +    g_free(iTask.err_str);
> +    return r;
> +}
> +
>  
>  static const char *const iscsi_strong_runtime_opts[] = {
>      "transport",
> @@ -2451,6 +2868,14 @@ static BlockDriver bdrv_iscsi = {
>      .bdrv_co_writev        = iscsi_co_writev,
>      .bdrv_co_flush_to_disk = iscsi_co_flush,
>  
> +    .bdrv_co_pr_read_keys     = iscsi_co_pr_read_keys,
> +    .bdrv_co_pr_read_reservation = iscsi_co_pr_read_reservation,
> +    .bdrv_co_pr_register      = iscsi_co_pr_register,
> +    .bdrv_co_pr_reserve       = iscsi_co_pr_reserve,
> +    .bdrv_co_pr_release       = iscsi_co_pr_release,
> +    .bdrv_co_pr_clear         = iscsi_co_pr_clear,
> +    .bdrv_co_pr_preempt       = iscsi_co_pr_preempt,
> +
>  #ifdef __linux__
>      .bdrv_aio_ioctl   = iscsi_aio_ioctl,
>  #endif
> -- 
> 2.20.1
>
Stefan Hajnoczi July 11, 2024, 1:05 p.m. UTC | #2 
On Tue, Jul 09, 2024 at 10:47:06AM +0800, Changqi Lu wrote:
> Add persistent reservation in/out operations for iscsi driver.
> The following methods are implemented: bdrv_co_pr_read_keys,
> bdrv_co_pr_read_reservation, bdrv_co_pr_register, bdrv_co_pr_reserve,
> bdrv_co_pr_release, bdrv_co_pr_clear and bdrv_co_pr_preempt.
> 
> Signed-off-by: Changqi Lu <luchangqi.123@bytedance.com>
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
> ---
>  block/iscsi.c | 425 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 425 insertions(+)

Aside from the g_free() issue I commented on:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff mbox series

Patch

diff --git a/block/iscsi.c b/block/iscsi.c
index 2ff14b7472..ba51f6d016 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -96,6 +96,7 @@  typedef struct IscsiLun {
     unsigned long *allocmap_valid;
     long allocmap_size;
     int cluster_size;
+    uint8_t pr_cap;
     bool use_16_for_rw;
     bool write_protected;
     bool lbpme;
@@ -280,6 +281,10 @@  iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
                     iTask->err_code = -error;
                     iTask->err_str = g_strdup(iscsi_get_error(iscsi));
                 }
+            } else if (status == SCSI_STATUS_RESERVATION_CONFLICT) {
+                iTask->err_code = -EBADE;
+                error_report("iSCSI Persistent Reservation Conflict: %s",
+                             iscsi_get_error(iscsi));
             }
         }
     }
@@ -1792,6 +1797,50 @@  static void iscsi_save_designator(IscsiLun *lun,
     }
 }
 
+/*
+ *  Ensure iscsi_open() must succeed, weather or not the target
+ *  implement SCSI_PR_IN_REPORT_CAPABILITIES.
+ */
+static void iscsi_get_pr_cap_sync(IscsiLun *iscsilun)
+{
+    struct scsi_task *task = NULL;
+    struct scsi_persistent_reserve_in_report_capabilities *rc = NULL;
+    int retries = ISCSI_CMD_RETRIES;
+    int xferlen = sizeof(struct scsi_persistent_reserve_in_report_capabilities);
+
+    do {
+        if (task != NULL) {
+            scsi_free_scsi_task(task);
+            task = NULL;
+        }
+
+        task = iscsi_persistent_reserve_in_sync(iscsilun->iscsi,
+               iscsilun->lun, SCSI_PR_IN_REPORT_CAPABILITIES, xferlen);
+        if (task != NULL && task->status == SCSI_STATUS_GOOD) {
+                rc = scsi_datain_unmarshall(task);
+                if (rc == NULL) {
+                    error_report("iSCSI: Failed to unmarshall "
+                                 "report capabilities data.");
+                } else {
+                    iscsilun->pr_cap =
+                    scsi_pr_cap_to_block(rc->persistent_reservation_type_mask);
+                    iscsilun->pr_cap |= (rc->ptpl_a) ? BLK_PR_CAP_PTPL : 0;
+                }
+                break;
+        }
+    } 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_report("iSCSI: failed to send report capabilities command.");
+    }
+
+    if (task) {
+        scsi_free_scsi_task(task);
+    }
+}
+
 static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
                       Error **errp)
 {
@@ -2024,6 +2073,7 @@  static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
         bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
     }
 
+    iscsi_get_pr_cap_sync(iscsilun);
 out:
     qemu_opts_del(opts);
     g_free(initiator_name);
@@ -2110,6 +2160,8 @@  static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
         bs->bl.opt_transfer = pow2floor(iscsilun->bl.opt_xfer_len *
                                         iscsilun->block_size);
     }
+
+    bs->bl.pr_cap = iscsilun->pr_cap;
 }
 
 /* Note that this will not re-establish a connection with an iSCSI target - it
@@ -2408,6 +2460,371 @@  out_unlock:
     return r;
 }
 
+static int coroutine_fn
+iscsi_co_pr_read_keys(BlockDriverState *bs, uint32_t *generation,
+                      uint32_t num_keys, uint64_t *keys)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    QEMUIOVector qiov;
+    struct IscsiTask iTask;
+    int xferlen = sizeof(struct scsi_persistent_reserve_in_read_keys) +
+                  sizeof(uint64_t) * num_keys;
+    g_autofree uint8_t *buf = g_malloc0(xferlen);
+    int32_t num_collect_keys = 0;
+    int r = 0;
+
+    qemu_iovec_init_buf(&qiov, buf, xferlen);
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_in_task(iscsilun->iscsi,
+                 iscsilun->lun, SCSI_PR_IN_READ_KEYS, xferlen,
+                 iscsi_co_generic_cb, &iTask);
+
+    if (iTask.task == NULL) {
+        qemu_mutex_unlock(&iscsilun->mutex);
+        return -ENOMEM;
+    }
+
+    scsi_task_set_iov_in(iTask.task, (struct scsi_iovec *)qiov.iov, qiov.niov);
+    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 PERSISTENT_RESERVE_IN failed: %s", iTask.err_str);
+        r = iTask.err_code;
+        goto out;
+    }
+
+    memcpy(generation, &buf[0], 4);
+    *generation = be32_to_cpu(*generation);
+    memcpy(&num_collect_keys, &buf[4], 4);
+    num_collect_keys = be32_to_cpu(num_collect_keys) / sizeof(uint64_t);
+    if (num_collect_keys > num_keys) {
+        r = -EINVAL;
+        goto out;
+    }
+
+    for (int i = 0; i < num_collect_keys; i++) {
+        memcpy(&keys[i], &buf[8 + i * 8], 8);
+        keys[i] = be64_to_cpu(keys[i]);
+    }
+    r = num_collect_keys;
+
+out:
+    qemu_mutex_unlock(&iscsilun->mutex);
+    g_free(iTask.err_str);
+    g_free(buf);
+    return r;
+}
+
+static int coroutine_fn
+iscsi_co_pr_read_reservation(BlockDriverState *bs, uint32_t *generation,
+                             uint64_t *key, BlockPrType *type)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    QEMUIOVector qiov;
+    struct IscsiTask iTask;
+    int xferlen = sizeof(struct scsi_persistent_reserve_in_read_reservation);
+    g_autofree uint8_t *buf = g_malloc0(xferlen);
+    uint8_t scope_type = 0;
+    int32_t num_collect_keys = 0;
+    int r = 0;
+
+    qemu_iovec_init_buf(&qiov, buf, xferlen);
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_in_task(iscsilun->iscsi,
+                 iscsilun->lun, SCSI_PR_IN_READ_RESERVATION,
+                 xferlen, iscsi_co_generic_cb, &iTask);
+
+    if (iTask.task == NULL) {
+        qemu_mutex_unlock(&iscsilun->mutex);
+        return -ENOMEM;
+    }
+
+    scsi_task_set_iov_in(iTask.task, (struct scsi_iovec *)qiov.iov, qiov.niov);
+    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 PERSISTENT_RESERVE_IN failed: %s", iTask.err_str);
+        r = iTask.err_code;
+        goto out;
+    }
+
+    memcpy(generation, &buf[0], 4);
+    *generation = be32_to_cpu(*generation);
+    memcpy(key, &buf[8], 8);
+    *key = be64_to_cpu(*key);
+    memcpy(&scope_type, &buf[21], 1);
+    *type = scsi_pr_type_to_block(scope_type & 0xf);
+    memcpy(&num_collect_keys, &buf[4], 4);
+    r = be32_to_cpu(num_collect_keys) / sizeof(uint64_t);
+out:
+    qemu_mutex_unlock(&iscsilun->mutex);
+    g_free(iTask.err_str);
+    g_free(buf);
+    return r;
+}
+
+static int coroutine_fn
+iscsi_co_pr_register(BlockDriverState *bs, uint64_t old_key,
+                     uint64_t new_key, BlockPrType type,
+                     bool ptpl, bool ignore_key)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    struct IscsiTask iTask;
+    struct scsi_persistent_reserve_out_basic basic;
+    SCSIPrOutAction action = ignore_key ? SCSI_PR_OUT_REG_AND_IGNORE_KEY :
+                                          SCSI_PR_OUT_REGISTER;
+    int r = 0;
+
+    basic.reservation_key = old_key;
+    basic.service_action_reservation_key = new_key;
+    basic.aptpl = ptpl ? 1 : 0;
+
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
+                 iscsilun->lun, action, 0, block_pr_type_to_scsi(type),
+                 &basic, 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_reserve(BlockDriverState *bs, uint64_t key, BlockPrType type)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    struct IscsiTask iTask;
+    struct scsi_persistent_reserve_out_basic basic;
+    int r = 0;
+
+    basic.reservation_key = key;
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
+                 iscsilun->lun, SCSI_PR_OUT_RESERVE, 0,
+                 block_pr_type_to_scsi(type), &basic,
+                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_release(BlockDriverState *bs, uint64_t key, BlockPrType type)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    struct IscsiTask iTask;
+    struct scsi_persistent_reserve_out_basic basic;
+    int r = 0;
+
+    basic.reservation_key = key;
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
+                 iscsilun->lun, SCSI_PR_OUT_RELEASE, 0,
+                 block_pr_type_to_scsi(type), &basic,
+                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_clear(BlockDriverState *bs, uint64_t key)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    struct IscsiTask iTask;
+    struct scsi_persistent_reserve_out_basic basic;
+    int r = 0;
+
+    basic.reservation_key = key;
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
+                 iscsilun->lun, SCSI_PR_OUT_CLEAR, 0, 0, &basic,
+                 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.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 PERSISTENT_RESERVE_OUT failed: %s", 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_pr_preempt(BlockDriverState *bs, uint64_t old_key,
+                    uint64_t new_key, BlockPrType type, bool abort)
+{
+    IscsiLun *iscsilun = bs->opaque;
+    struct IscsiTask iTask;
+    struct scsi_persistent_reserve_out_basic basic;
+    SCSIPrOutAction action = abort ? SCSI_PR_OUT_PREEMPT_AND_ABORT :
+                                     SCSI_PR_OUT_PREEMPT;
+    int r = 0;
+
+    basic.reservation_key = old_key;
+    basic.service_action_reservation_key = new_key;
+
+    iscsi_co_init_iscsitask(iscsilun, &iTask);
+    qemu_mutex_lock(&iscsilun->mutex);
+retry:
+    iTask.task = iscsi_persistent_reserve_out_task(iscsilun->iscsi,
+                 iscsilun->lun, action, 0, block_pr_type_to_scsi(type),
+                 &basic, 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.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 PERSISTENT_RESERVE_OUT failed: %s", iTask.err_str);
+        r = iTask.err_code;
+    }
+
+    qemu_mutex_unlock(&iscsilun->mutex);
+
+    g_free(iTask.err_str);
+    return r;
+}
+
 
 static const char *const iscsi_strong_runtime_opts[] = {
     "transport",
@@ -2451,6 +2868,14 @@  static BlockDriver bdrv_iscsi = {
     .bdrv_co_writev        = iscsi_co_writev,
     .bdrv_co_flush_to_disk = iscsi_co_flush,
 
+    .bdrv_co_pr_read_keys     = iscsi_co_pr_read_keys,
+    .bdrv_co_pr_read_reservation = iscsi_co_pr_read_reservation,
+    .bdrv_co_pr_register      = iscsi_co_pr_register,
+    .bdrv_co_pr_reserve       = iscsi_co_pr_reserve,
+    .bdrv_co_pr_release       = iscsi_co_pr_release,
+    .bdrv_co_pr_clear         = iscsi_co_pr_clear,
+    .bdrv_co_pr_preempt       = iscsi_co_pr_preempt,
+
 #ifdef __linux__
     .bdrv_aio_ioctl   = iscsi_aio_ioctl,
 #endif