Bug 1515604 - qemu-img info: failed to get "consistent read" lock on a mirroring image
Summary: qemu-img info: failed to get "consistent read" lock on a mirroring image
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.5
Hardware: Unspecified
OS: Unspecified
low
low
Target Milestone: rc
: ---
Assignee: Kevin Wolf
QA Contact: Qianqian Zhu
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-11-21 05:52 UTC by Han Han
Modified: 2018-04-11 00:51 UTC (History)
13 users (show)

Fixed In Version: qemu-kvm-rhev-2.10.0-17.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-04-11 00:49:36 UTC


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Links
System ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2018:1104 None None None 2018-04-11 00:51:20 UTC

Description Han Han 2017-11-21 05:52:00 UTC
Description of problem:
As subject

Version-Release number of selected component (if applicable):
qemu-kvm-rhev-2.10.0-6.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
Create this bug to track an upstream issue discussion:
http://lists.nongnu.org/archive/html/qemu-discuss/2017-11/msg00045.html

# /usr/libexec/qemu-kvm -name A -machine pc,accel=kvm \
-vnc 0.0.0.0:1 \
-monitor stdio \
-qmp tcp:0:5555,server,nowait \
-serial unix:/tmp/monitor,server,nowait \
-drive file=/var/lib/libvirt/images/V.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0

QEMU 2.10.0 monitor - type 'help' for more information
(qemu) drive_mirror drive-virtio-blk0 /var/lib/libvirt/images/V.new
Formatting '/var/lib/libvirt/images/V.new', fmt=qcow2 size=10737418240 cluster_size=65536 lazy_refcounts=off refcount_bits=16

# qemu-img info /var/lib/libvirt/images/V.new -U
qemu-img: Could not open '/var/lib/libvirt/images/V.new': Failed to get "consistent read" lock
Is another process using the image?

Actual results:
As above

Expected results:
Could query image info on mirroring image by -U option.

Additional info:

Comment 2 Kevin Wolf 2017-11-21 11:25:36 UTC
Fix is on the mailing list:

[PATCH for-2.11 0/2] Fix 'qemu-img info' on mirror target
https://lists.gnu.org/archive/html/qemu-block/2017-11/msg00796.html

Comment 3 Kevin Wolf 2017-11-30 16:54:03 UTC
Turns out this fixed only raw images, but not image formats. Sent a follow-up:

[PATCH] block: Formats don't need CONSISTENT_READ with NO_IO
http://lists.gnu.org/archive/html/qemu-block/2017-11/msg01191.html

Comment 5 Miroslav Rezanina 2018-01-16 13:44:24 UTC
Fix included in qemu-kvm-rhev-2.10.0-17.el7

Comment 7 Qianqian Zhu 2018-01-17 02:39:50 UTC
Reproduced on qemu-kvm-rhev-10:2.10.0-14.el7.x86_64:

Steps:
1. Launch guest:
/usr/libexec/qemu-kvm \
-name A \
-machine pc,accel=kvm \
-monitor stdio \
-drive file=/home/kvm_autotest_root/images/rhel74-64-virtio.qcow2,format=qcow2,if=none,id=drive-virtio-blk0,werror=stop,rerror=stop  \
-device virtio-blk-pci,drive=drive-virtio-blk0,id=virtio-blk0

2. Block mirror:
(qemu) drive_mirror drive-virtio-blk0 mirror

3. # qemu-img info -U mirror

Results:
Can't get image information.
# qemu-img info -U mirror
qemu-img: Could not open 'mirror': Failed to get "consistent read" lock
Is another process using the image?

Verified on qemu-kvm-rhev-2.10.0-17.el7.x86_64:
Steps same as above. 
Results:
Get image information correctly.
# qemu-img info -U mirror
image: mirror
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 1.9G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

Moving to VERIFIED.

Comment 10 errata-xmlrpc 2018-04-11 00:49:36 UTC
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


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