[dm-devel] ios and sectors should be incremented on completion

[Akira Hayakawa]

Thanks for information Junichi,

> Do you have a problem with the current behavior other than the document?
No. I and my colleagues just wondered why.

> AFAIR, dm increments ios/sectors at submission because md did.
> And other bio-based drivers such as drbd and nvme seem to have followed
> the precedence.
> 
> While md has a reason to do so (some md personalities just remaps bios
> and doesn't track completion), dm should be able to collect stat
> in dec_pending as it always clones.
Very interesting historical background.
Maybe bache, too.

> So, I think it's ok to move ios/sectors counting to end_io_acct().
> It might make tools like iostat happier.
> You might want to fix other bio-based drivers as well.
I want to hear comments from DM maintainers on this issue.

- Akira