Bug 698924 – qcow2: Reads fail with backing file smaller than snapshot

Bug 698924 - qcow2: Reads fail with backing file smaller than snapshot

Summary:	qcow2: Reads fail with backing file smaller than snapshot

Status:	CLOSED WONTFIX

Aliases:	None

Product:	Red Hat Enterprise Linux 5
Classification:	Red Hat
Component:	kvm (Show other bugs)
Sub Component:
Version:	5.7
Hardware:	Unspecified Unspecified

Priority	medium Severity medium
Target Milestone:	rc
Target Release:	---
Assigned To:	Kevin Wolf
QA Contact:	Virtualization Bugs
Docs Contact:

URL:
Whiteboard:
Keywords:

Depends On:	688147
Blocks:	Rhel5KvmTier1
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Reported:	2011-04-22 06:02 EDT by juzhang
Modified:	2013-01-09 18:49 EST (History)
CC List:	7 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:	688147
Environment:
Last Closed:	2011-06-06 10:39:49 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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Comment 1 Kevin Wolf 2011-05-03 11:23:54 EDT

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 14:27:44 EDT

Kevin,

What is the proposed solution for RHEL5, then ?

Comment 4 Kevin Wolf 2011-06-06 10:39:49 EDT

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.

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