[LTP] [RFC PATCH 1/2] tst_acquire_device: clear first sectors of LTP_DEV

[Stanislav Kholmanskikh]

Hi!

On 02/22/2016 01:34 PM, Cyril Hrubis wrote:
> Hi!
>> As we see in [1] ZAP_BOOTBLOCK is defined on all archs except SPARC.
>> I could not find the exact reason why it's so, but tend to think
>> that it was implemented to let ext{2,3,4} be created on the first
>> partition of a Sun disk label. The thing is that with Sun disk labels
>> it's absolutely fine to have the first partition starting at sector 0,
>> which is used by the disk label itself:
>>
>> ~# fdisk -lu /dev/vdiska
>>
>> Disk /dev/vdiska (Sun disk label): 255 heads, 63 sectors, 3916 cylinders
>> Units = sectors of 1 * 512 bytes
>>
>>        Device Flag    Start       End    Blocks   Id  System
>> /dev/vdiska1             0   2104515   1052257+   1  Boot
>> /dev/vdiska2       2104515  62910540  30403012+  83  Linux native
>> /dev/vdiska3             0  62910540  31455270    5  Whole disk
>>
>> If mkfs.ext{2,3,4} overwrote the first two sectors, then
>> 'mkfs.ext{2,3,4} /dev/vdiska1' would destroy the disk label.
>>
>> Clearing the first 512k of LTP_DEV solves this issue. I don't expect
>> it to make a noticeable impact on test execution time. 512k is fine
>> to cover superblocks of all file systems supported by libblkid [2].
>> Just in case.
>
> Sounds reasonable to me. I guess that we can remove the special cases
> for the force flag once this is applied as well.
>

I committed the series. Thank you.

Regarding the force flag. Yes, we no longer need it now.

I tried to execute mount* test cases with ext2/ext3/xfs/btrfs file 
systems with the attached patch and they all passed.

So am I proceeding with a more formal patch?
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