1000428 – virt-format uses wrong partition type for vfat filesystems

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Bug 1000428 - virt-format uses wrong partition type for vfat filesystems

Summary: virt-format uses wrong partition type for vfat filesystems

Keywords:
Status:	CLOSED CURRENTRELEASE
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	libguestfs
Sub Component:
Version:	7.0
Hardware:	Unspecified
OS:	Unspecified
Priority:	unspecified
Severity:	unspecified
Target Milestone:	rc
Target Release:	---
Assignee:	Richard W.M. Jones
QA Contact:	Virtualization Bugs
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2013-08-23 12:39 UTC by Gerd Hoffmann
Modified:	2014-06-18 02:01 UTC (History)
CC List:	4 users (show)
Fixed In Version:	libguestfs-1.22.6-5.el7
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2014-06-13 12:48:50 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Description Gerd Hoffmann 2013-08-23 12:39:48 UTC

Description of problem:
$subject

Version-Release number of selected component (if applicable):
libguestfs-tools-c-1.22.5-3.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. qemu-img create -f qcow2 "$file" "$size"
2. virt-format --add "$file" --format=qcow2 --partition=mbr --filesystem=vfat
3. attach image as usb disk to windows guest

Actual results:
usbstick doesn't show up in Windows Explorer

Expected results:
usbstick can be used without much fuss

Additional info:
The partition is created with type 0x83 (Linux).
When partitioning the stick using windows it will pick 0x0b (W95 FAT32),
virt-format should to the same.

While being at it: Having a --label=<text> cmd line switch (to specify a volume label for the filesystem) would be great too.  Wanna have a separate RFE bug for this?

Comment 1 Richard W.M. Jones 2013-08-23 12:52:23 UTC

Doh.  We fixed the same problem in virt-make-fs too ...

(In reply to Gerd Hoffmann from comment #0)
> While being at it: Having a --label=<text> cmd line switch (to specify a
> volume label for the filesystem) would be great too.  Wanna have a separate
> RFE bug for this?

Don't worry, I'll fix them both.

Comment 3 Richard W.M. Jones 2013-08-29 11:23:29 UTC

Fixed upstream in the following commits:

https://github.com/libguestfs/libguestfs/commit/d432ab2b5a965110bab542bfd397785eee9753dd
https://github.com/libguestfs/libguestfs/commit/c46e41cb3c41f6283e0350cac6ef0b9178ed3941
https://github.com/libguestfs/libguestfs/commit/e17cd73fb7e3d7ce5e28f51c8451033f48a39153
https://github.com/libguestfs/libguestfs/commit/a75ca610b80614253f8a9d9828a97dc61d919b8a

Comment 4 Lingfei Kong 2013-10-10 06:53:40 UTC

Can reproduce with libguestfs-tools-c-1.22.5-3.el7.x86_64

Steps to reproduce:
1. qemu-img create -f qcow2 test.img 100M
2. virt-format --add test.img --format=qcow2 --partition=mbr --filesystem=vfat
3. attach image as usb disk to windows guest

Result:
usbstick doesn't show up in Windows Explorer

Comment 5 Richard W.M. Jones 2013-10-10 07:50:34 UTC

(In reply to Lingfei Kong from comment #4)
> Can reproduce with libguestfs-tools-c-1.22.5-3.el7.x86_64
> 
> Steps to reproduce:
> 1. qemu-img create -f qcow2 test.img 100M
> 2. virt-format --add test.img --format=qcow2 --partition=mbr
> --filesystem=vfat
> 3. attach image as usb disk to windows guest

When attaching the image, did you ensure the format is set
to qcow2?  If you set it to raw then Windows would just see
a qcow2 header, everything would be completely broken.

> Result:
> usbstick doesn't show up in Windows Explorer

Can you run:

virt-filesystems -a test.img --all --long -h

The output should show that the MBR byte is set to 0b.
For examples see:
https://github.com/libguestfs/libguestfs/commit/d432ab2b5a965110bab542bfd397785eee9753dd

Comment 6 Lingfei Kong 2013-10-11 03:11:25 UTC

(In reply to Richard W.M. Jones from comment #5)

> When attaching the image, did you ensure the format is set
> to qcow2?  If you set it to raw then Windows would just see
> a qcow2 header, everything would be completely broken.

Yes, I specified the format as qcow2 in the steps showed in commnet #4, here is the command I used to attach the image file:
/usr/libexec/qemu-kvm -m 1024 -name "VM" -drive file=/root/win.img -usbdevice disk:format=qcow2:/test.img

> Can you run:
> 
> virt-filesystems -a test.img --all --long -h
> 
> The output should show that the MBR byte is set to 0b.

I checked the image file(showed in comment #4, it is created with command: virt-format --add test.img --format=qcow2 --partition=mbr --filesystem=vfat
) with virt-filesystems  tool, the following is the output:
[host]#virt-filesystems -a test.img --all --long -h
Name       Type        VFS   Label  MBR  Size  Parent
/dev/sda1  filesystem  vfat  -      -    100M  -
/dev/sda1  partition   -     -      83   100M  /dev/sda
/dev/sda   device      -     -      -    100M  -

It shows the MBR byte is 83 not 0b.

Comment 7 Richard W.M. Jones 2013-10-11 11:14:26 UTC

I'm just reading back more closely.  It looks like you have
correctly reproduced the original problem with 1.22.5.

The bug should be fixed in libguestfs >= 1.22.6-5.el7.

Comment 9 Lingfei Kong 2013-12-06 08:25:04 UTC

Verified it with libguestfs-1.22.6-15.el7

Steps to verify: 
1. #qemu-img create -f qcow2 test.img 100M

2. #virt-format --add test.img --format=qcow2 --partition=mbr --filesystem=vfat

3. attach image as usb disk to windows guest
#/usr/libexec/qemu-kvm -m 1024 -name "VM" -drive file=/var/lib/libvirt/images/vm1.img -usbdevice disk:format=qcow2:/root/lkong/test.img -vnc :0

4.
 # virt-filesystems -a test.img --all --long -h
Name       Type        VFS   Label  MBR  Size  Parent
/dev/sda1  filesystem  vfat  -      -    100M  -
/dev/sda1  partition   -     -      0b   100M  /dev/sda
/dev/sda   device      -     -      -    100M  -


Result:
1. usbstick shows up in Windows Explorer.
2. It shows the MBR byte is 0b in step 4. 

So, this bug is fixed.

Comment 10 Ludek Smid 2014-06-13 12:48:50 UTC

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.

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