Some information about direct-io support on ubifs

[Zhihao Cheng]

在 2024/11/11 17:37, Michael Nazzareno Trimarchi 写道:
> Hi all
> 
> I would like to have some information on how to implement direct-io
> support in ubifs. I have tried to mount squashfs image as file in
> ubifs using loopback and direct-io but it seems that loop can not
> handle when this is on top of ubifs. From what I understand from the
> code it seems that the requirement is that the direct-io is
> implemented in the filesystem where the file is stored. I have
> simulated using nand sim. The idea is to reduce the buffering. I'm
> open to have other suggestions regarding this too.
> 
> Michael
> .
> 
Hi Michael,
There is a discussion(9 years ago) about ubifs dio[1], of course we 
cannot implement it as a fake interface now.
Before talking about adding dio support for UBIFS, let me know some 
background information. What's the purpose of using dio for opening 
squashfs image file? What's the goal of reducing buffer you mentioned 
above, Better performance? Less memory usage?


[1] 
https://lore.kernel.org/lkml/1440016553-26481-2-git-send-email-richard@nod.at/