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Description of problem:
The RHEL 7 qemu implements a newer version of the qcow2 image file format,
which enables new features, but cannot be read by older qemu versions. For new
images, the version can be specified using the 'qemu-img create -o
compat=(0.10|1.1)' option. Bug 1026739 requests to make compat=1.1 the default
for new images.
Upstream qemu allows to upgrade existing images to make use of the new features
and downgrade images to make them usable with older qemu versions (such as the
one of RHEL 6).
This does not work in RHEL 7.
Version-Release number of selected component (if applicable):
qemu-kvm-1.5.3-19.el7
How reproducible:
100%
Steps to Reproduce:
A.1 qemu-img create -f qcow2 -o compat=0.10 /tmp/test.qcow2 1G
A.2 qemu-img amend -f qcow2 -o compat=1.1 /tmp/test.qcow2
A.3 qemu-img info /tmp/test.qcow2
B.1 qemu-img create -f qcow2 -o compat=1.1 /tmp/test.qcow2 1G
B.2 qemu-img amend -f qcow2 -o compat=0.10 /tmp/test.qcow2
B.3 qemu-img info /tmp/test.qcow2
Actual results:
Step 2 in each case prints the qemu-img help message.
Expected results:
All commands succeed. In A.3, "compat: 1.1" is printed. In B.3, "compat: 0.10"
is printed.
Comment 1Miroslav Rezanina
2014-01-09 09:41:41 UTC
Reproduced this bug with qemu-kvm-1.5.3-19.el7.x86_64 & qemu-img-1.5.3-19.el7.x86_64
Steps:
A.
1.#qemu-img create -f qcow2 -o compat=0.10 /tmp/test.qcow2 1G
2.check help of qemu-img
# qemu-img --help |grep amend
#
* there's no help infos about amend
3.#qemu-img amend -f qcow2 -o compat=1.1 /tmp/test.qcow2
* this command can not be executed, just output the help infos of qemu-img
B.
1.# qemu-img create -f qcow2 -o compat=1.1 /tmp/test.qcow2 1G
2.# qemu-img amend -f qcow2 -o compat=0.10 /tmp/test.qcow2
* this command can not be executed, just output the help infos of qemu-img
So this bug is reproduced by qemu-kvm-1.5.3-19.el7.x86_64 & qemu-img-1.5.3-19.el7.x86_64
Verify this bug with qemu-kvm-1.5.3-37.el7.x86_64 & qemu-img-1.5.3-37.el7.x86_64
Steps:
A.
1.# qemu-img create -f qcow2 -o compat=0.10 /tmp/test.qcow2 1G
Formatting '/tmp/test.qcow2', fmt=qcow2 size=1073741824 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off
2.check help of qemu-img
# qemu-img --help |grep amend
amend [-q] [-f fmt] -o options filename
3.# qemu-img amend -f qcow2 -o compat=1.1 /tmp/test.qcow2
* command can be finished successfully
4.# qemu-img info /tmp/test.qcow2
image: /tmp/test.qcow2
file format: qcow2
virtual size: 1.0G (1073741824 bytes)
disk size: 196K
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: false
So the compat is successfully upgrated to 1.1
B
1.# qemu-img create -f qcow2 -o compat=1.1 /tmp/test.qcow2 1G
Formatting '/tmp/test.qcow2', fmt=qcow2 size=1073741824 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off
2.# qemu-img amend -f qcow2 -o compat=0.10 /tmp/test.qcow2
3.# qemu-img info /tmp/test.qcow2
image: /tmp/test.qcow2
file format: qcow2
virtual size: 1.0G (1073741824 bytes)
disk size: 196K
cluster_size: 65536
Format specific information:
compat: 0.10
So the compat is successfully downgrade to 0.10
So according to above, this bug has been fixed.
This request was resolved in Red Hat Enterprise Linux 7.0.
Contact your manager or support representative in case you have further questions about the request.