Bug 1029308

Summary:	misleading error message inside the guest when trying to format a read-only disk
Product:	Red Hat Enterprise Linux 7	Reporter:	Sibiao Luo <sluo>
Component:	qemu-kvm	Assignee:	Fam Zheng <famz>
Status:	CLOSED NOTABUG	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	low	Docs Contact:
Priority:	low
Version:	7.0	CC:	acathrow, chayang, famz, hhuang, juzhang, michen, pbonzini, qzhang, sluo, virt-bugs, virt-maint, xfu
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-12-23 08:06:22 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:

Description Sibiao Luo 2013-11-12 06:39:13 UTC

Description of problem:
Boot guest with a VMDK format disk which specified read-only, and then format it in guest with a wrong authority permitted message.
BTW, if use rhel6.5 guest in rhel7.0 host to test which did not meet such issue.

Version-Release number of selected component (if applicable):
host info:
3.10.0-48.el7.x86_64
qemu-kvm-1.5.3-19.el7.x86_64
guest info:
3.10.0-48.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.boot guest with a VMDK format disk which specified read-only.
e.g:...-drive file=/home/RHEL-7.0-20131030.1-Server-x86_64.vmdk,if=none,id=drive-data-disk,format=vmdk,cache=none,werror=stop,rerror=stop,readonly=on -device virtio-blk-pci,bus=pci.0,addr=0x7,drive=drive-data-disk,id=data-disk
2.format it in guest.
# mkfs.ext4 /dev/vda

Actual results:
after step 2, the VMDK disk(/dev/vda) has a wrong authority permitted message.
# mkfs.ext4 /dev/vda
mke2fs 1.42.8 (20-Jun-2013)
/dev/vda is apparently in use by the system; will not make a filesystem here!

Expected results:
It should prompt a warning message(Operation not permitted), like:
# mkfs.ext4 /dev/vda
/dev/vda: Operation not permitted while setting up superblock

Additional info:

Comment 1 Sibiao Luo 2013-11-12 06:52:34 UTC

My RHEL-7.0-20131030.1-Server-x86_64.vmdk was installed by VMware-Workstation-9.0.0-812388.x86_64.

# qemu-img info /home/RHEL-7.0-20131030.1-Server-x86_64.vmdk
image: /home/RHEL-7.0-20131030.1-Server-x86_64.vmdk
file format: vmdk
virtual size: 10G (10737418240 bytes)
disk size: 932M
Format specific information:
    cid: 1535971103
    parent cid: 4294967295
    create type: monolithicSparse
    extents:
        [0]:
            virtual size: 10737418240
            filename: /home/RHEL-7.0-20131030.1-Server-x86_64.vmdk
            cluster size: 65536
            format: 

Best Regards,
sluo

Comment 2 Ademar Reis 2013-12-18 10:41:19 UTC

The error message should be the same no matter which image format you use. Can you try formating a qcow2 image attached as read-only as well?

Comment 3 Paolo Bonzini 2013-12-18 12:10:14 UTC

> # mkfs.ext4 /dev/vda
> mke2fs 1.42.8 (20-Jun-2013)
> /dev/vda is apparently in use by the system; will not make a filesystem here!

This typically means that the device is partitioned (so you wanted /dev/vda1) or mounted already somewhere.

Try booting into a new VM where the disk is writable, "dd if=/dev/zero of=/dev/vda bs=10M count=1", then retry this testcase.

Comment 5 Sibiao Luo 2013-12-23 07:07:13 UTC

(In reply to Paolo Bonzini from comment #3)
> > # mkfs.ext4 /dev/vda
> > mke2fs 1.42.8 (20-Jun-2013)
> > /dev/vda is apparently in use by the system; will not make a filesystem here!
> 
> This typically means that the device is partitioned (so you wanted
> /dev/vda1) or mounted already somewhere.
Yes, I also agree with you, as my RHEL-7.0-20131030.1-Server-x86_64.vmdk has file system which install rhel7.0 guest in it.
> Try booting into a new VM where the disk is writable, "dd if=/dev/zero
> of=/dev/vda bs=10M count=1", then retry this testcase.
this have no such issue that prompt operation not permitted. Even there is no need to dd, just create a new qcow2/raw image with the same testing which has not meet such issue.
e.g:...-drive file=/home/my-data-disk.qcow2,if=none,id=drive-data-disk,format=qcow2,cache=none,werror=stop,rerror=stop,readonly=on -device virtio-blk-pci,bus=pci.0,addr=0x7,drive=drive-data-disk,id=data-disk
guest]# mkfs.ext4 /dev/vda
mke2fs 1.42.8 (20-Jun-2013)
/dev/vda: Operation not permitted while setting up superblock

Best Regards,
sluo