Christoph Hellwig [off-list ref] writes:

I myself

Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

to [5/7] fat part though,

That being said, I really detest adding weird query modes to random
syscalls.  We should expose capabilities through the interface that
was designed for such things: (f)pathconf, as there are a lot more
important parameters we currently fail to expose to userspace to
start with.

This is true. For example, max link count. And it might be able to use
for fs's bug/issue detection too (in past, userland has to add
workaround for all cases, because noway to detect the buggy or not).

Thanks.
-- 
OGAWA Hirofumi [off-list ref]