*** Bug 1206107 has been marked as a duplicate of this bug. ***

The block job can be forced cancel, by adding the option "force":true, e.g.:


{ "execute": "block-job-cancel", 
      "arguments": { 
           "device": "drive-scsi0-0-0",
            "force":true
       }
}


I'm not sure if this was tried in the originally reported version of qemu or not, and perhaps the option was broken; either way, it works with the current upstream QEMU and with v2.8.0 if you pass in "force":true. 

Verified working on upstream QEMU v2.8.0 and master, here are the relevant QAPI commands and responses:

{ "execute": "qmp_capabilities" }
{"return": {}}

{
    "arguments": {
        "device": "virtio0",
        "format": "qcow2",
        "mode": "absolute-paths",
        "sync": "full",
        "on-source-error": "stop",
        "on-target-error": "stop",
        "target": "iscsi://192.168.15.180/iqn.2017-01.com.quasiquark:for.all/2"
    },
    "execute": "drive-mirror"
}

Formatting 'iscsi://192.168.15.180/iqn.2017-01.com.quasiquark:for.all/2', fmt=qcow2 size=272730423296 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
{"return": {}}
qemu-system-x86_64: iSCSI Failure: SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:LBA_OUT_OF_RANGE(0x2100)
{"timestamp": {"seconds": 1485469318, "microseconds": 327399}, "event": "BLOCK_JOB_ERROR", "data": {"device": "virtio0", "operation": "write", "action": "stop"}}

{ "execute" : "query-block-jobs" }
{"return": [{"io-status": "nospace", "device": "virtio0", "busy": false, "len": 4023386112, "offset": 9961472, "paused": true, "speed": 0, "ready": false, "type": "mirror"}]}


First without the force option:
{ "execute": "block-job-cancel", "arguments": { "device": "virtio0" } }
{"error": {"class": "GenericError", "desc": "The block job for device 'virtio0' is currently paused"}}


Now with the force option:
{ "execute": "block-job-cancel", "arguments": { "device": "virtio0", "force":true } }
{"return": {}}
{"timestamp": {"seconds": 1485470262, "microseconds": 134118}, "event": "BLOCK_JOB_CANCELLED", "data": {"device": "virtio0", "len": 4023386112, "offset": 9961472, "speed": 0, "type": "mirror"}}

{ "execute" : "query-block-jobs" }
{"return": []}



I am moving this to POST with a fixed-in-version of 2.8.0 to be safe, so that it can be retested by QE.

Verified with:
qemu-kvm-rhev-2.8.0-5.el7.x86_64
kernel-3.10.0-566.el7.x86_64

Currently, the machinism of block job is a bit different, It will not cancel the block job when it hits no enough space error, the job is simply pause and qmp will prompt errors, wait for space being extended. So this bug actually not exist now. And I have tried cancel block job with "force=true" option after it is paused, it works.

Steps and result:
1. Launch guest with:
 /usr/libexec/qemu-kvm -cpu SandyBridge  -m 4G -device virtio-scsi-pci,bus=pci.0,addr=0x5,id=scsi0 -drive file=iscsi://10.66.8.116:3260/iqn.2014-09.org.openstack:my-iscsi-volume/1,if=none,id=drive-scsi0-0-0,media=disk,cache=none,format=raw,werror=stop,rerror=stop,aio=native -qmp tcp:0:5555,server,nowait   -spice port=5939,disable-ticketing  -vga qxl -global qxl-vga.revision=3 -monitor stdio
2. Drive mirror to a small iscsi disk:
{ "execute": "drive-mirror", "arguments": { "device": "drive-scsi0-0-0", "target": "iscsi://10.66.8.116:3260/iqn.2014-09.org.openstack:my-iscsi-volume/2", "format": "raw", "mode": "existing", "sync": "full", "speed": 1000000000, "on-source-error": "stop", "on-target-error": "stop" } }
3. Cancel block job when after qmp prompt error:
1) Without option "force=true"
{ "execute": "block-job-cancel", "arguments": { "device": "drive-scsi0-0-0"} }
2) With option force=true":
{ "execute": "block-job-cancel", "arguments": { "device": "drive-scsi0-0-0", "force":true } }

Result:
After step2:
qmp prompt error, and block job is paused.
{"timestamp": {"seconds": 1489051314, "microseconds": 833099}, "event": "BLOCK_JOB_ERROR", "data": {"device": "drive-scsi0-0-0", "operation": "write", "action": "stop"}}

After step 3.1:
block job can't be cancelled:
{"error": {"class": "GenericError", "desc": "The block job for device 'drive-scsi0-0-0' is currently paused"}}

After step 3.2:
Block job is cancelled successfully:
{"timestamp": {"seconds": 1489050854, "microseconds": 825732}, "event": "BLOCK_JOB_CANCELLED", "data": {"device": "drive-scsi0-0-0", "len": 21474836480, "offset": 524288000, "speed": 1000000000, "type": "mirror"}}

In conclusion, this bug is fixed, moving to verified.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392