incomplete erase of btrfs with wipefs

incomplete erase of btrfs with wipefs

[Chris Murphy]

Hi,

I'm not completely sure if this is a wipefs bug, or a btrfs(-progs) bug. The gist is that after using wipefs on a btrfs formatted partition, then reformatted as ext4, mount sees it as ext4, parted sees it as ext4, but I btrfs fi show sees it as a member device of a btrfs volume. I have filed a bug against util-linux, but perhaps this is a btrfs-progs over confidence in what it thinks is a valid volume. I have included in the bug report the first 5MB of the device.

https://bugzilla.redhat.com/show_bug.cgi?id=889888


Chris Murphy

Re: incomplete erase of btrfs with wipefs

[Goffredo Baroncelli]

Hi, Chrism

On 12/23/2012 10:11 PM, Chris Murphy wrote:
> Hi,
> 
> I'm not completely sure if this is a wipefs bug, or a btrfs(-progs)
> bug. The gist is that after using wipefs on a btrfs formatted
> partition, then reformatted as ext4, mount sees it as ext4, parted
> sees it as ext4, but I btrfs fi show sees it as a member device of a
> btrfs volume. I have filed a bug against util-linux, but perhaps this
> is a btrfs-progs over confidence in what it thinks is a valid volume.
> I have included in the bug report the first 5MB of the device.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=889888

I cannot reproduce this behaviour [1]. However I have to point out that
this [2][3] patch solved a problem like you reported.

Which version of btrfs-progs do you have ? It seems that F18 (beta)
already has the latest btrfs-progs suite..

BR
G.Baroncelli


[1]

ghigo@venice:~$ /sbin/mkfs.btrfs /dev/sdi1 -L test

WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL
WARNING! - see http://btrfs.wiki.kernel.org before using

fs created label test on /dev/sdi1
	nodesize 4096 leafsize 4096 sectorsize 4096 size 7.45GB
Btrfs Btrfs v0.19
ghigo@venice:~$ btrfs fi show /dev/sdi1
[...]
Label: 'test'  uuid: 64df10e0-7131-449d-84ec-a5babdd6199e
	Total devices 1 FS bytes used 28.00KB
	devid    1 size 7.45GB used 799.25MB path /dev/sdi1

Btrfs v0.19-101-g3891d2d
ghigo@venice:~$ /sbin/wipefs /dev/sdi1
offset               type
----------------------------------------------------------------
0x10040              btrfs   [filesystem]
                     LABEL: test
                     UUID:  64df10e0-7131-449d-84ec-a5babdd6199e

ghigo@venice:~$ /sbin/wipefs /dev/sdi1 -o 0x10040
8 bytes were erased at offset 0x10040 (btrfs)
they were: 5f 42 48 52 66 53 5f 4d
ghigo@venice:~$ btrfs fi show /dev/sdi1
Btrfs v0.19-101-g3891d2d
ghigo@venice:~$ /sbin/blkid | grep sdi1
ghigo@venice:~$ /sbin/wipefs /dev/sdi1


[2]
http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-progs.git;a=commitdiff;h=6eba9002956ac40db87d42fb653a0524dc568810;hp=bc130ecd0260e4ee6ffe07ae43fc90db281a4daa

[3] http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg18649.html

> 
> 
> Chris Murphy
> 
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Re: incomplete erase of btrfs with wipefs

[Chris Murphy]

On Dec 24, 2012, at 10:52 AM, Goffredo Baroncelli <kreijack@gmail.com> wrote:

> Hi, Chrism
> 
> On 12/23/2012 10:11 PM, Chris Murphy wrote:
>> Hi,
>> 
>> I'm not completely sure if this is a wipefs bug, or a btrfs(-progs)
>> bug. The gist is that after using wipefs on a btrfs formatted
>> partition, then reformatted as ext4, mount sees it as ext4, parted
>> sees it as ext4, but I btrfs fi show sees it as a member device of a
>> btrfs volume. I have filed a bug against util-linux, but perhaps this
>> is a btrfs-progs over confidence in what it thinks is a valid volume.
>> I have included in the bug report the first 5MB of the device.
>> 
>> https://bugzilla.redhat.com/show_bug.cgi?id=889888
> 
> I cannot reproduce this behaviour [1]. However I have to point out that
> this [2][3] patch solved a problem like you reported.
> 
> Which version of btrfs-progs do you have ? It seems that F18 (beta)
> already has the latest btrfs-progs suite..

This happens with the current F18 test candidates, which have btrfs-progs-0.20.rc1.20121017git91d9eec-1.fc18


Chris Murphy