Bug 1320114
| Summary: | qemu prompt "main-loop: WARNING: I/O thread spun for 1000 iterations" when block mirror from format qcow2 to raw | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Qianqian Zhu <qizhu> |
| Component: | qemu-kvm-rhev | Assignee: | John Snow <jsnow> |
| Status: | CLOSED ERRATA | QA Contact: | Qianqian Zhu <qizhu> |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 7.4 | CC: | chayang, juzhang, knoel, michen, mrezanin, qizhu, virt-maint, xfu, yuhuang |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2018-04-11 00:09:32 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Hit same issue when do live commit.
Details:
1. Boot guest
# /usr/libexec/qemu-kvm -m 4G \
-drive file=rhel74.qcow2,if=none,format=qcow2,id=drive0 -device virtio-blk-pci,id=blk0,drive=drive0 \
-monitor stdio -vnc :1 \
-netdev tap,id=tap0 -device virtio-net-pci,netdev=tap0,id=net0 \
-numa node -sandbox on -qmp tcp:0:4444,server,nowait
2. Create 4 snapshots
{ "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive0", "snapshot-file": "/root/sn1", "format": "qcow2"} }
{"return": {}}
{ "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive0", "snapshot-file": "/root/sn2", "format": "qcow2"} }
{"return": {}}
{ "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive0", "snapshot-file": "/root/sn3", "format": "qcow2"} }
{"return": {}}
{ "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive0", "snapshot-file": "/root/sn4", "format": "qcow2"} }
{"return": {}}
3. Do live commit
{ "execute": "block-commit", "arguments": { "device": "drive0", "base": "/root/sn1", "top": "/root/sn3", "speed": 1000000000 } }
{"return": {}}
HMP shows the warning:
(qemu) Formatting '/root/sn1', fmt=qcow2 size=42949672960 backing_file=rhel74.qcow2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
(qemu) Formatting '/root/sn2', fmt=qcow2 size=42949672960 backing_file=/root/sn1 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
(qemu) Formatting '/root/sn3', fmt=qcow2 size=42949672960 backing_file=/root/sn2 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
(qemu) Formatting '/root/sn4', fmt=qcow2 size=42949672960 backing_file=/root/sn3 backing_fmt=qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
(qemu) main-loop: WARNING: I/O thread spun for 1000 iterations
Add qemu and kernel version to comment 2: qemu-kvm-rhev-2.9.0-5.el7 kernel-3.10.0-666.el7.x86_64 (In reply to Qianqian Zhu from comment #0) > Description of problem: > qemu prompt "main-loop: WARNING: I/O thread spun for 1000 iterations" when > block mirror from format raw to raw > > Version-Release number of selected component (if applicable): > kernel-3.10.0-365.el7.x86_64 > qemu-kvm-rhev-2.5.0-2.el7.x86_64 > > guest: > rhel7.2: kernel-3.10.0-327.el7.x86_64 > > How reproducible: > 3/3 > > Steps to Reproduce: > 1.launch guest with qcow2 format image: > qemu-kvm -cpu host -m 1024 -device > virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive > file=/home/RHEL-Server-7.2-64-virtio.qcow2,format=qcow2,if=none,id=drive- > virtio-blk0,werror=stop,rerror=stop -device > virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-disk0 -vnc :1 -monitor > stdio -netdev tap,id=hostnet0,vhost=on -device > virtio-net-pci,netdev=hostnet0,id=net0,mac=3C:D9:2B:09:AB:44,bus=pci.0, > addr=0x4 -qmp tcp:0:5555,server,nowait > 2.block mirror from qcow2 to raw: > { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", > "target": "/home/mirror1.qcow2", "format": "qcow2", "mode": > "absolute-paths", "sync": "full", "on-source-error": "stop", > "on-target-error": "stop", "granularity": 65536, "buf-size": 655360 } } (A) From the instructions given, this mirrors from qcow2 to qcow2. (B) Is the buf-size here intentional? 655360 looks like a typo. > 3.{"execute": "block-job-complete", "arguments": { "device": > "drive-virtio-blk0"} } > 4. block mirror from raw to raw: > { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", > "target": "/home/mirror2.raw", "format": "raw", "mode": "absolute-paths", > "sync": "full", "on-source-error": "stop", "on-target-error": "stop", > "granularity": 65536, "buf-size": 655360 } } > (C) Given the above, this looks like qcow2-to-raw. > Actual results: > after step 4: > (qemu) Formatting '/home/mirror2.raw', fmt=raw size=21474836480 > main-loop: WARNING: I/O thread spun for 1000 iterations > > Expected results: > no warning prompt > > Additional info: > Can't reproduce this issue if launch a raw format guest and block mirror to > raw image directly. My attempt: Step 2: (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror1.qcow2 format=qcow2 mode=absolute-paths sync=full on-source-error=stop on-target-error=stop granularity=65536 buf-size=655360 {"return": {}} (QEMU) {u'timestamp': {u'seconds': 1513629294, u'microseconds': 846094}, u'data': {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, u'offset': 1588396032}, u'event': u'BLOCK_JOB_READY'} Step 3: (QEMU) block-job-complete device=drive0 {"return": {}} (QEMU) {u'timestamp': {u'seconds': 1513629339, u'microseconds': 922111}, u'data': {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, u'offset': 1588396032}, u'event': u'BLOCK_JOB_COMPLETED'} Step 4: (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror2.raw format=raw mode=absolute-paths sync=full on-source-error=stop on-target-error=stop granularity=65536 buf-size=655360 {"return": {}} (QEMU) {u'timestamp': {u'seconds': 1513629560, u'microseconds': 408998}, u'data': {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, u'offset': 1588396032}, u'event': u'BLOCK_JOB_READY'} step 5: (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror2.raw format=raw mode=absolute-paths sync=full on-source-error=stop on-target-error=stop granularity=65536 buf-size=655360 {"return": {}} Couldn't reproduce on latest upstream; this may have been fixed there. Is this still reproducible downstream? the reproduction instructions don't match the bug title, so I am worried I am not attempting this correctly. (In reply to John Snow from comment #4) > (In reply to Qianqian Zhu from comment #0) > > Description of problem: > > qemu prompt "main-loop: WARNING: I/O thread spun for 1000 iterations" when > > block mirror from format raw to raw > > > > Version-Release number of selected component (if applicable): > > kernel-3.10.0-365.el7.x86_64 > > qemu-kvm-rhev-2.5.0-2.el7.x86_64 > > > > guest: > > rhel7.2: kernel-3.10.0-327.el7.x86_64 > > > > How reproducible: > > 3/3 > > > > Steps to Reproduce: > > 1.launch guest with qcow2 format image: > > qemu-kvm -cpu host -m 1024 -device > > virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive > > file=/home/RHEL-Server-7.2-64-virtio.qcow2,format=qcow2,if=none,id=drive- > > virtio-blk0,werror=stop,rerror=stop -device > > virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-disk0 -vnc :1 -monitor > > stdio -netdev tap,id=hostnet0,vhost=on -device > > virtio-net-pci,netdev=hostnet0,id=net0,mac=3C:D9:2B:09:AB:44,bus=pci.0, > > addr=0x4 -qmp tcp:0:5555,server,nowait > > 2.block mirror from qcow2 to raw: > > { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", > > "target": "/home/mirror1.qcow2", "format": "qcow2", "mode": > > "absolute-paths", "sync": "full", "on-source-error": "stop", > > "on-target-error": "stop", "granularity": 65536, "buf-size": 655360 } } > > (A) From the instructions given, this mirrors from qcow2 to qcow2. > (B) Is the buf-size here intentional? 655360 looks like a typo. Yes, the buf-size is intentional, it tries to be 10 times granularity. > > > 3.{"execute": "block-job-complete", "arguments": { "device": > > "drive-virtio-blk0"} } > > > 4. block mirror from raw to raw: > > { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", > > "target": "/home/mirror2.raw", "format": "raw", "mode": "absolute-paths", > > "sync": "full", "on-source-error": "stop", "on-target-error": "stop", > > "granularity": 65536, "buf-size": 655360 } } > > > > (C) Given the above, this looks like qcow2-to-raw. That's right, it should be qcow2 to raw, I wrongly described in the title, sorry for that. > > > Actual results: > > after step 4: > > (qemu) Formatting '/home/mirror2.raw', fmt=raw size=21474836480 > > main-loop: WARNING: I/O thread spun for 1000 iterations > > > > Expected results: > > no warning prompt > > > > Additional info: > > Can't reproduce this issue if launch a raw format guest and block mirror to > > raw image directly. > > > > My attempt: > > Step 2: > > (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror1.qcow2 > format=qcow2 mode=absolute-paths sync=full on-source-error=stop > on-target-error=stop granularity=65536 buf-size=655360 > {"return": {}} > > (QEMU) > {u'timestamp': {u'seconds': 1513629294, u'microseconds': 846094}, u'data': > {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, > u'offset': 1588396032}, u'event': u'BLOCK_JOB_READY'} > > Step 3: > > (QEMU) block-job-complete device=drive0 > {"return": {}} > > (QEMU) > {u'timestamp': {u'seconds': 1513629339, u'microseconds': 922111}, u'data': > {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, > u'offset': 1588396032}, u'event': u'BLOCK_JOB_COMPLETED'} > > Step 4: > > (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror2.raw > format=raw mode=absolute-paths sync=full on-source-error=stop > on-target-error=stop granularity=65536 buf-size=655360 > {"return": {}} > > (QEMU) > {u'timestamp': {u'seconds': 1513629560, u'microseconds': 408998}, u'data': > {u'device': u'drive0', u'type': u'mirror', u'speed': 0, u'len': 1588396032, > u'offset': 1588396032}, u'event': u'BLOCK_JOB_READY'} > > > step 5: > > (QEMU) drive-mirror device=drive0 target=/media/ext/img/mirror2.raw > format=raw mode=absolute-paths sync=full on-source-error=stop > on-target-error=stop granularity=65536 buf-size=655360 > {"return": {}} > > > > > Couldn't reproduce on latest upstream; this may have been fixed there. Is > this still reproducible downstream? the reproduction instructions don't > match the bug title, so I am worried I am not attempting this correctly. I have tested this scenario with qemu-kvm-rhev-2.10.0-12.el7.x86_64, the issue does not exist anymore. I think it is already fixed in latest qemu. Excellent, thank you for verifying. Marking this as MODIFIED, I'm not 100% sure what the correct end-state ought to be. (CLOSED CURRENTRELEASE?) 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-2018:1104 |
Description of problem: qemu prompt "main-loop: WARNING: I/O thread spun for 1000 iterations" when block mirror from format raw to raw Version-Release number of selected component (if applicable): kernel-3.10.0-365.el7.x86_64 qemu-kvm-rhev-2.5.0-2.el7.x86_64 guest: rhel7.2: kernel-3.10.0-327.el7.x86_64 How reproducible: 3/3 Steps to Reproduce: 1.launch guest with qcow2 format image: qemu-kvm -cpu host -m 1024 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive file=/home/RHEL-Server-7.2-64-virtio.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop -device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-disk0 -vnc :1 -monitor stdio -netdev tap,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=3C:D9:2B:09:AB:44,bus=pci.0,addr=0x4 -qmp tcp:0:5555,server,nowait 2.block mirror from qcow2 to raw: { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", "target": "/home/mirror1.qcow2", "format": "qcow2", "mode": "absolute-paths", "sync": "full", "on-source-error": "stop", "on-target-error": "stop", "granularity": 65536, "buf-size": 655360 } } 3.{"execute": "block-job-complete", "arguments": { "device": "drive-virtio-blk0"} } 4. block mirror from raw to raw: { "execute": "drive-mirror", "arguments": { "device": "drive-virtio-blk0", "target": "/home/mirror2.raw", "format": "raw", "mode": "absolute-paths", "sync": "full", "on-source-error": "stop", "on-target-error": "stop", "granularity": 65536, "buf-size": 655360 } } Actual results: after step 4: (qemu) Formatting '/home/mirror2.raw', fmt=raw size=21474836480 main-loop: WARNING: I/O thread spun for 1000 iterations Expected results: no warning prompt Additional info: Can't reproduce this issue if launch a raw format guest and block mirror to raw image directly.