Bug 1006963 - Buffer I/O error and end_request I/O error when hot-unplugging disks
Summary: Buffer I/O error and end_request I/O error when hot-unplugging disks
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: qemu
Version: 20
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Fedora Virtualization Maintainers
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2013-09-11 15:12 UTC by Lukáš Doktor
Modified: 2015-06-29 12:21 UTC (History)
9 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-06-29 12:21:59 UTC
Type: Bug


Attachments (Terms of Use)
Dmesg output of the simple reproducer with 2 disks and ~100 dd commands (164.78 KB, text/plain)
2013-09-11 15:12 UTC, Lukáš Doktor
no flags Details

Description Lukáš Doktor 2013-09-11 15:12:47 UTC
Created attachment 796440 [details]
Dmesg output of the simple reproducer with 2 disks and ~100 dd commands

Description of problem:
Hi guys, while developing a hotplug disk test I discovered many errors in dmesg:
[  521.035762] end_request: I/O error, dev vde, sector 16
[  521.036746] quiet_error: 104 callbacks suppressed
[  521.036746] Buffer I/O error on device vde, logical block 2

Well I expect some failures since I'm writing into/from device, which is being removed. The question is, whether all these messages can be just dropped or whether they signalize some odd behavior.


Version-Release number of selected component (if applicable):
Host (F19)
qemu-kvm-1.4.2-7.fc19.x86_64
Guest (F19)
kernel-3.9.5-301.fc19.x86_64

How reproducible:
Every few seconds

Steps to Reproduce (Human readable):
1. execute qemu
2. in qemu start writing into the last vd* disk (except vda*)
3. start hotplugging and unplugging disks (I started with one disk, but it's quicker to reproduce it with 2 disks).

Steps to Reproduce (commands):
1. [host terminal 1] qemu-kvm -drive if=none,file=f19-64.qcow2,id=aaa -device virtio-blk-pci,drive=aaa -chardev socket,id=hmp1,path=/tmp/hmp1,server,nowait -mon chardev=hmp1,mode=readline -smp 4
2. [guest terminal] touch /tmp/stress ; while [ -f /tmp/stress ]; do dd if=/dev/urandom of=`ls /dev/vd* | egrep -e '^/dev/vda[0-9]*$' | tail -n 1` oflag=direct conv=nocreat; done
3. ^^ the above couple of times
4. [host terminal 2] while :; do echo -e "drive_add auto id=drive_disk,if=none,file=/tmp/disk.qcow2\ndevice_add virtio-blk-pci,id=disk,drive=drive_disk\ndrive_add auto id=drive_disk2,if=none,file=/tmp/disk2.qcow2\ndevice_add virtio-blk-pci,id=disk2,drive=drive_disk2" | sudo socat /tmp/hmp1 - ; sleep 1 ; echo -e "device_del disk\ndrive_del drive_disk" | sudo socat /tmp/hmp1 - ; qemu-img check /tmp/disk.qcow2 || break ; echo -e "device_del disk2\ndrive_del drive_disk2" | sudo socat /tmp/hmp1 - ; qemu-img check /tmp/disk2.qcow2 || break; sleep  1 ; done

Actual results:
It seems to work, only dmesg reports messages about end_requests ...

Expected results:
Honestly I don't know. If the messages makes sense than it works fine. Otherwise there are messages which makes me suspicious.

Additional info:
This is just simple reproducer. The test do this with multiple disks and with >20 disks I occasionally got "Leaked clusters" while verifying the image directly after unplug. Than I put 3s sleep after the unplug (of all disks) and this problem disappeared.

Comment 1 Fedora End Of Life 2015-01-09 19:48:19 UTC
This message is a notice that Fedora 19 is now at end of life. Fedora 
has stopped maintaining and issuing updates for Fedora 19. It is 
Fedora's policy to close all bug reports from releases that are no 
longer maintained. Approximately 4 (four) weeks from now this bug will
be closed as EOL if it remains open with a Fedora 'version' of '19'.

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Comment 2 Lukáš Doktor 2015-01-21 16:11:16 UTC
Retested on:

host: kernel-3.17.2-200.fc20.x86_64
qemu: upstream tag v2.2.0-rc5
guest: kernel-3.17.8-200.fc20

with the same results:
2015-01-21 16:38:24: [   36.182855] Buffer I/O error on device vds, logical block 122
2015-01-21 16:38:24: [   36.206852] Buffer I/O error on device vds, logical block 122
2015-01-21 16:38:24: [   36.211361] Buffer I/O error on device vds, logical block 64
2015-01-21 16:38:24: [   36.253743] Buffer I/O error on device vds, logical block 64
2015-01-21 16:38:24: [   36.258549] Buffer I/O error on device vds, logical block 16384
2015-01-21 16:38:24: [   36.261136] Buffer I/O error on device vds, logical block 16384
2015-01-21 16:38:24: [   36.268162] Buffer I/O error on device vds, logical block 512
...

Comment 3 Fedora End Of Life 2015-05-29 09:23:29 UTC
This message is a reminder that Fedora 20 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 20. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '20'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 20 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 4 Fedora End Of Life 2015-06-29 12:21:59 UTC
Fedora 20 changed to end-of-life (EOL) status on 2015-06-23. Fedora 20 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
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bug.

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