Bug 1259229

*** Bug 1249883 has been marked as a duplicate of this bug. ***

Fix included in qemu-kvm-rhev-2.3.0-23.el7

Summary: When I tested with qemu-kvm-rhev-2.3.0-21.el7.x86_64, the qemu is responsive, qmp monitor works well, just guest hang. Then I also tried lower version, qemu-kvm-rhev-2.3.0-12.el7.x86_64, and this bug is reproduced.
I verified this bug with qemu-kvm-rhev-2.3.0-23.el7, the results below can prove that this bug has been fixed well.


Reproduced:
1 guest hang, qemu works well
Host:
Kernel:3.10.0-315.el7.x86_64
qemu-kvm-rhev:qemu-kvm-rhev-2.3.0-21.el7.x86_64

Steps:
1.1 boot guest
/usr/libexec/qemu-kvm -name rhel6.7z -machine pc-i440fx-rhel7.2.0,accel=kvm \
-cpu SandyBridge -m 4G,slots=256,maxmem=40G -numa node \
-smp 4,sockets=2,cores=2,threads=1 \
-uuid 82b1a01e-5f6c-4f5f-8d27-3855a74e6b61 \
-netdev tap,id=hostnet0 \
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=12:54:00:5c:88:61 \
-device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vgamem_mb=16 \
-vnc 0.0.0.0:1 \
-monitor stdio \
-qmp tcp:0:5555,server,nowait \
-serial unix:/tmp/monitor,server,nowait \
-drive file=/mnt/disk4/rhel6.7_virtio.raw,format=raw,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0 \

1.2 do drive-mirror, guest hang.
QEMU 2.3.0 monitor - type 'help' for more information
(qemu) drive_mirror drive-virtio-blk0 /mnt/disk4/mirror.raw
Formatting '/mnt/disk4/mirror.raw', fmt=raw size=21474836480
(qemu) 
(qemu) 
(qemu) 
(qemu) 
(qemu) info status
VM status: running
(qemu) 
(qemu) 
(qemu) 
(qemu) info status
VM status: running
(qemu)

1.3 query mirror job, no data is written to the target image.
{ "execute" : "query-block-jobs", "arguments" : {} }
{"return": []}
{ "execute" : "query-block-jobs", "arguments" : {} }
{"return": [{"io-status": "ok", "device": "drive-virtio-blk0", "busy": false, "len": 0, "offset": 0, "paused": false, "speed": 0, "ready": false, "type": "mirror"}]}
{ "execute" : "query-block-jobs", "arguments" : {} }
{"return": [{"io-status": "ok", "device": "drive-virtio-blk0", "busy": false, "len": 0, "offset": 0, "paused": false, "speed": 0, "ready": false, "type": "mirror"}]}


2 guest hang, qemu hang
Host:
Kernel:3.10.0-315.el7.x86_64
qemu-kvm-rhev:qemu-kvm-rhev-2.3.0-12.el7.x86_64

Steps:
2.1 boot guest
Same command with step 1.1 

2.2 do drive-mirror, qemu hang. And guest hang.
(qemu) drive_mirror drive-virtio-blk0 /mnt/disk4/mirror.raw
Formatting '/mnt/disk4/mirror.raw', fmt=raw size=21474836480

2.3 query mirror job, qmp not return, qmp monitor hang.
{ "execute" : "query-block-jobs", "arguments" : {} }



Verified:
Host:
Kernel:3.10.0-315.el7.x86_64
qemu-kvm-rhev:qemu-kvm-rhev-2.3.0-23.el7.x86_64

Prerequisites: 
raw image file on ext4.

Steps:
1. boot guest
# /usr/libexec/qemu-kvm -name rhel6.7z -machine pc-i440fx-rhel7.2.0,accel=kvm \
-cpu SandyBridge -m 4G,slots=256,maxmem=40G -numa node \
-smp 4,sockets=2,cores=2,threads=1 \
-uuid 82b1a01e-5f6c-4f5f-8d27-3855a74e6b61 \
-netdev tap,id=hostnet0 \
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=12:54:00:5c:88:61 \
-device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vgamem_mb=16 \
-vnc 0.0.0.0:1 \
-monitor stdio \
-qmp tcp:0:5555,server,nowait \
-serial unix:/tmp/monitor,server,nowait \
-drive file=/mnt/disk4/rhel6.7_virtio.raw,format=raw,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0 \

2. drive-mirror
(1) drive-mirror in qemu monitor, and query mirror job
(qemu) drive_mirror drive-virtio-blk0 /mnt/disk4/mirror.raw
Formatting '/mnt/disk4/mirror.raw', fmt=raw size=21474836480

{ "execute" : "query-block-jobs", "arguments" : {} }
{"return": [{"io-status": "ok", "device": "drive-virtio-blk0", "busy": true, "len": 21474967552, "offset": 11681136640, "paused": false, "speed": 0, "ready": false, "type": "mirror"}]}

{"timestamp": {"seconds": 1442368656, "microseconds": 681306}, "event": "BLOCK_JOB_READY", "data": {"device": "drive-virtio-blk0", "len": 21475360768, "offset": 21475360768, "speed": 0, "type": "mirror"}}

(2)reopen 
{"execute": "block-job-complete", "arguments": { "device": "drive-virtio-blk0"} }
{"return": {}}
{"timestamp": {"seconds": 1442368751, "microseconds": 886669}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "drive-virtio-blk0", "len": 21477588992, "offset": 21477588992, "speed": 0, "type": "mirror"}}

(qemu) info block
drive-virtio-blk0: /mnt/disk4/mirror.raw (raw)
    Cache mode:       writeback
...

3. qemu and guest both work well. After reboot guest sever times, they still work well.


I also tried xfs, it works well. So this bug is fixed.

*** Bug 1263046 has been marked as a duplicate of this bug. ***

According to comment6, set this issue as 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://rhn.redhat.com/errata/RHBA-2015-2546.html