Re: [PATCH] fat: ignore .. subdir and always add a link to dirs

[OGAWA Hirofumi]

Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxx> writes:

> On Fri, Feb 23, 2024 at 10:52:12AM +0900, OGAWA Hirofumi wrote:
>> Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxx> writes:
>> 
>> > The tools used for creating images for the Lego Mindstrom EV3 are not
>> > adding '.' and '..' entry in the 'Projects' directory.
>> >
>> > Without this fix, the kernel can not fill the inode structure for
>> > 'Projects' directory.
>> >
>> > See https://github.com/microsoft/pxt-ev3/issues/980
>> > And https://github.com/microsoft/uf2-linux/issues/6
>> >
>> > When counting the number of subdirs, ignore .. subdir and add one when
>> > setting the initial link count for directories. This way, when .. is
>> > present, it is still accounted for, and when neither . or .. are present, a
>> > single link is still done, as it should, since this link would be the one
>> > from the parent directory.
>> >
>> > With this fix applied, we can mount an image with such empty directories,
>> > access them, create subdirectories and remove them.
>> 
>> This looks like the bug of those tools, isn't it?
>> 
>> Thanks.
>> -- 
>> OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
>
> Which they refused to fix, arguing that there are already filesystems out there
> in the world like that. Also, there is argument that this works on Windows,
> though I haven't been able to test this.
>
> https://github.com/microsoft/pxt-ev3/issues/980
> https://github.com/microsoft/uf2-linux/issues/6

OK.

If you want to add the workaround for this, it must emulate the correct
format. I.e. sane link count even if without "."/"..". And furthermore
it works for any operations.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>