Re: [RFC] fsblock

[Nick Piggin <npiggin@suse.de>]

Just clarify a few things. Don't you hate rereading a long work you
wrote? (oh, you're supposed to do that *before* you press send?).

On Sun, Jun 24, 2007 at 03:45:28AM +0200, Nick Piggin wrote:
> 
> I'm announcing "fsblock" now because it is quite intrusive and so I'd
> like to get some thoughts about significantly changing this core part
> of the kernel.
> 
> fsblock is a rewrite of the "buffer layer" (ding dong the witch is
> dead), which I have been working on, on and off and is now at the stage
> where some of the basics are working-ish. This email is going to be
> long...
> 
> Firstly, what is the buffer layer?  The buffer layer isn't really a
> buffer layer as in the buffer cache of unix: the block device cache
> is unified with the pagecache (in terms of the pagecache, a blkdev
> file is just like any other, but with a 1:1 mapping between offset
> and block).

I mean, in Linux, the block device cache is unified. UNIX I believe
did all its caching in a buffer cache, below the filesystem.

 
> - Large block support. I can mount and run an 8K block size minix3 fs on
>   my 4K page system and it didn't require anything special in the fs. We

Oh, and I don't have a Linux mkfs that makes minixv3 filesystems.
I had an image kindly made for me because I don't use minix. If
you want to test large block support, I won't email it to you though:
you can just convert ext2 or ext3 to fsblock ;)