Re: JFFS2 mount time

Gareth Bult (Encryptec)
2004-12-17T15:33:04Z

Hi,

On Fri, 2004-12-17 at 06:54 -0600, Josh Boyer wrote:

> Hm, ok. An alternative to using the system buffer would be to make
> JFFS[23] use a write buffer for those devices.

Forgive my ignorance .. but what's the difference between using a write
buffer and using the system buffer ?

>From my pov, the system buffer is there, already 100% reliable and
somewhat larger than any [potential] write buffer ???

(Given the system buffer uses the underlying block devices read / write
routines and the block device emulator will typically sit on a block
device such as a hard drive or USB flash key .. [?])

> It's already done on
> NAND which has some special handling. The support for ECC'd NOR
> probably matches more closely what you'd want to do. Take a look at
> wbuf.c.

Mmm, after looking at wbuf.c I'm none the wiser as to what it does or
how it relates ..

> Well, if it's better than the original we can always take yours and
> replace what's there. Send it on, performance gains are always
> welcome. I'm sure there are others interested in what you've done that
> will review the code.

I think once I get this FL release out the way I'll have a a more
in-depth look at JFFS*. It seems to be written almost exclusively for
MTD devices .. which is great .. for MTD devices .. but for block
devices and flash (USB for example) presented through a standard
interface (SCSI for example) it seems there is scope for a much
"thinner" filesystem generic devices with a subset of JFFS's feature
set.

Gareth.