Re: [RFC PATCH v5 06/10] ovl: implement overlayfs' ->write_inode operation

[Miklos Szeredi]

On Thu, 7 Oct 2021 at 15:10, Chengguang Xu <cgxu519@xxxxxxxxxxxx> wrote:
>  > However that wasn't what I was asking about.  AFAICS ->write_inode()
>  > won't start write back for dirty pages.   Maybe I'm missing something,
>  > but there it looks as if nothing will actually trigger writeback for
>  > dirty pages in upper inode.
>  >
>
> Actually, page writeback on upper inode will be triggered by overlayfs ->writepages and
> overlayfs' ->writepages will be called by vfs writeback function (i.e writeback_sb_inodes).

Right.

But wouldn't it be simpler to do this from ->write_inode()?

I.e. call write_inode_now() as suggested by Jan.

Also could just call mark_inode_dirty() on the overlay inode
regardless of the dirty flags on the upper inode since it shouldn't
matter and results in simpler logic.

Thanks,
Miklos


>
> Thanks,
> Chengguang
>
>
>