Re: [dm-devel] [PATCH RFC] dm snapshot: shared exception store

[FUJITA Tomonori <fujita tomonori lab ntt co jp>]

On Tue, 12 Aug 2008 05:56:57 -0700
Daniel Phillips <phillips phunq net> wrote:

> Hi tomonori,
> 
> An impressive patch.

Thanks, and thanks a lot for the nice snapshot code.


>  You just want to use getblk for alloc_chunk_buffer,
> not vmalloc.

I think that it means that we cache all the chunks, both btree chunks
and the data chunks (which are passed to the upper layer such as file
systems). I think that we don't want cache the latter in dm.


> That is what the buffer cache is for, and that is why I
> emulated it in userspace.
> 
> More comments later.

Thanks.

I'll post a new patchset in a more reasonable format shortly (tomorrow
or day after tomorrow, hopefully).