Bug 888008

Summary:	RFE: qemu-img should be able to report the amount of space used by a qcow2 image stored on a block device
Product:	Red Hat Enterprise Linux 6	Reporter:	Federico Simoncelli <fsimonce>
Component:	qemu-kvm	Assignee:	Kevin Wolf <kwolf>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	urgent	Docs Contact:
Priority:	unspecified
Version:	6.4	CC:	abaron, acathrow, areis, bsarathy, cpelland, italkohe, juzhang, kwolf, lnovich, mkenneth, mrezanin, pablo.iranzo, qzhang, sluo, tlavigne, virt-maint
Target Milestone:	rc	Keywords:	FutureFeature
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu-kvm-0.12.1.2-2.361.el6	Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:
Clones:	977089 (view as bug list)		Environment:
Last Closed:	2013-11-21 05:59:26 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:
Bug Depends On:
Bug Blocks:	647386, 887909, 896690, 977089, 1083310, 1196199

Description Federico Simoncelli 2012-12-17 20:02:25 UTC

Description of problem:
qemu-img should be able to report the amount of space used by a qcow2 image on a block device.

Version-Release number of selected component (if applicable):
qemu-img-0.12.1.2-2.295.el6_3.4.x86_64

Steps to Reproduce:
# vgcreate testvg01 /dev/mapper/1IET_00010001
# lvcreate -n lvtest01 -L 1G testvg01

# qemu-img create -f qcow2 /dev/testvg01/lvtest01 20G
Formatting '/dev/testvg01/lvtest01', fmt=qcow2 size=21474836480 encryption=off cluster_size=65536 

# qemu-img info /dev/testvg01/lvtest01
image: /dev/testvg01/lvtest01
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 65536

Actual results:
There is no command reporting how much space of /dev/testvg01/lvtest01 is in use by the qcow2 image.

Expected results:
qemu-img should provide a way to report the amount of space used.

Additional info:
A patch has been proposed upstream:

http://lists.gnu.org/archive/html/qemu-devel/2012-12/msg01153.html

which provides such functionality through the "check" command:

# qemu-img check /dev/testvg01/lvtest01
No errors were found on the image.
Highest offset in use: 262144

Comment 2 RHEL Program Management 2012-12-21 06:47:19 UTC

This request was not resolved in time for the current release.
Red Hat invites you to ask your support representative to
propose this request, if still desired, for consideration in
the next release of Red Hat Enterprise Linux.

Comment 22 Sibiao Luo 2013-07-01 08:59:57 UTC

Discuss with kwolf in IRC that 'Highest offset in use' has been renamed to 'Image end offset' during patch review. And i did not reproduce this issue with qemu-kvm-360 and qemu-kvm-355, both of them were ok. kwolf said that he git checkout qemu-kvm-0.12.1.2-2.360.el6.

Verify this issue on qemu-kvm-0.12.1.2-2.376.el6.x86_64.
host info:
# uname -r && rpm -q qemu-kvm
2.6.32-392.el6.x86_64
qemu-kvm-0.12.1.2-2.376.el6.x86_64

Steps and results:
1.create a lvm.
# pvcreate /dev/sdb
  Physical volume "/dev/sdb" successfully created
# vgcreate vg-90.100-sluo /dev/sdb
  Volume group "vg-90.100-sluo" successfully created
# lvcreate -L 20G -n lv-90-100-sluo /dev/vg-90.100-sluo
  Logical volume "lv-90-100-sluo" created
2.create qcow2 to the lvm.
# qemu-img create -f qcow2 /dev/vg-90.100-sluo/lv-90-100-sluo 20G
Formatting '/dev/vg-90.100-sluo/lv-90-100-sluo', fmt=qcow2 size=21474836480 encryption=off cluster_size=65536 lazy_refcounts=off 
3.check the image info.
# qemu-img info /dev/vg-90.100-sluo/lv-90-100-sluo
image: /dev/vg-90.100-sluo/lv-90-100-sluo
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 0
cluster_size: 65536

# qemu-img check /dev/vg-90.100-sluo/lv-90-100-sluo
No errors were found on the image.
Image end offset: 262144

4.check if it's there with --output=json
# qemu-img check /dev/vg-90.100-sluo/lv-90-100-sluo --output=json
{
    "image-end-offset": 262144, 
    "total-clusters": 327680, 
    "check-errors": 0, 
    "filename": "/dev/vg-90.100-sluo/lv-90-100-sluo", 
    "format": "qcow2"
}

Base on above, this issue has been fixed correctly, set verified status. please correct me if any mistake.

Best Regards,
sluo

Comment 24 errata-xmlrpc 2013-11-21 05:59:26 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.

http://rhn.redhat.com/errata/RHSA-2013-1553.html