Re: [PATCH v2 7/7] btrfs-progs: Doc/mkfs: Add extra condition for rootdir option

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2017年09月15日 23:48, David Sterba wrote:
> On Fri, Sep 15, 2017 at 09:24:19PM +0800, Qu Wenruo wrote:
>>> I'm going to review & merge this series to devel. Tests and
>>> documentation should be updated to make the usecase clear.
>>
>> I'm happy to address any comment, both code and doc/test.
> 
> For the tests I'd like to see:
> 
> * with file target, try non-existent file, zero-length file, too-small
>    file and large-enough

No problem.

But it would be better to define the expected behavior first.
I'll show the behavior difference below to see if you're OK with it.

For non-existent file:
New: Fail, no such file at the very beginning
Old: Create new one

Zero-length:
New: Fail, too small file at the very beginning
Old: Expand file and continue mkfs

Too-small:
New: Fail, showing -28 errno half way
Old: Same as zero length.

Large-enough:
New: Success, without shrink
Old: Success, shrink

> 
> * for block device target, I think loop device would do, too-small and
>    large-enough

Same as above too-small and large-enough case.

> 
> * after the test, verify that the files have same size and contents

I'll reuse convert facilities to do that.

And I'll add one extra test case:
No enough privilege to read some file in the directory:
New: Fail gracefully
Old: Fail with BUG_ON.

If you're OK with the behavior difference, I'll create new test cases 
for mkfs --rootdir.

Thanks,
Qu