Bug 806300

Summary: info block shows backing file still exists after stream the entire chain
Product: Red Hat Enterprise Linux 6 Reporter: Shaolong Hu <shu>
Component: qemu-kvmAssignee: Marcelo Tosatti <mtosatti>
Status: CLOSED DUPLICATE QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 6.3CC: acathrow, bsarathy, jcody, juzhang, kwolf, michen, mkenneth, tburke, virt-maint
Target Milestone: rcKeywords: Reopened
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-03-26 13:01:28 UTC Type: ---
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: 806280    

Description Shaolong Hu 2012-03-23 11:58:27 UTC
Description of problem:
------------------------
after stream the entire chain, backing file still exists in info block output.


Version-Release number of selected component (if applicable):
--------------------------------------------------------------
qemu-kvm-0.12.1.2-2.262.el6rhev.x86_64


How reproducible:
-----------------
100%


Steps to Reproduce:
--------------------
1.(qemu) info block
drive-virtio-disk0: removable=0 io-status=ok file=/root/RHEL-Server-6.3-64-virtio.qcow2 ro=0 drv=qcow2 encrypted=0

2.(qemu) snapshot_blkdev drive-virtio-disk0 /root/sn1 qcow2
Formatting '/root/sn1', fmt=qcow2 size=21474836480 backing_file='/root/RHEL-Server-6.3-64-virtio.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 
(qemu) info block
drive-virtio-disk0: removable=0 io-status=ok file=/root/sn1 backing_file=/root/RHEL-Server-6.3-64-virtio.qcow2 ro=0 drv=qcow2 encrypted=0

3.(qemu) block_stream drive-virtio-disk0 

4.(qemu) info block-jobs 
No active jobs
(qemu) info block
drive-virtio-disk0: removable=0 io-status=ok file=/root/sn1 backing_file=/root/RHEL-Server-6.3-64-virtio.qcow2 ro=0 drv=qcow2 encrypted=0

5. quit qemu-kvm.

6.[root@shu ~]# qemu-img info sn1
image: sn1
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 20G
cluster_size: 65536


Expected results:
------------------
After block stream finishes, set backing file as null.

Comment 2 Dor Laor 2012-03-25 10:26:29 UTC
IIUC it creates another qcow2 file on top of the existing one so that's the expected behavior. Marcelo can verify it

Comment 3 Kevin Wolf 2012-03-26 09:19:16 UTC
This is a valid bug report.

bdrv_change_backing_file() was not designed to work from the system emulator and change the BlockDriverState accordingly. It needs to be extended to update bs.

Comment 4 Marcelo Tosatti 2012-03-26 13:00:31 UTC
The fix for BZ #801449 adjusts bs->backing_file correctly. Marking it as a duplicate of that bug.

Comment 5 Marcelo Tosatti 2012-03-26 13:01:28 UTC

*** This bug has been marked as a duplicate of bug 801449 ***