Bug 698924

Summary: qcow2: Reads fail with backing file smaller than snapshot
Product: Red Hat Enterprise Linux 5 Reporter: juzhang <juzhang>
Component: kvmAssignee: Kevin Wolf <kwolf>
Status: CLOSED WONTFIX QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.7CC: gcosta, juzhang, kwolf, michen, mkenneth, tburke, virt-maint
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 688147 Environment:
Last Closed: 2011-06-06 14:39:49 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: 688147    
Bug Blocks: 580949    

Comment 1 Kevin Wolf 2011-05-03 15:23:54 UTC
This is a completely different problem than in RHEL 6. What happens is that qemu-img completely ignores the request to create a 128 MB image and just makes sn1.qcow2 the same size as base.qcow2 (i.e. 64 MB). The read fails because part of it is after the end of the image.

Comment 2 Glauber Costa 2011-05-16 18:27:44 UTC
Kevin,

What is the proposed solution for RHEL5, then ?

Comment 4 Kevin Wolf 2011-06-06 14:39:49 UTC
Not worth fixing/backporting the feature. You can't create backing files that are smaller than the disk in RHEL 5 and it looks as if nobody has ever tried in practice.