Re: UBIFS in-place vs out-of-place GC

[Artem Bityutskiy <dedekind1@gmail.com>]

Hi,

On Wed, 2010-09-01 at 09:08 -0700, Russ Dill wrote:
> I'm doing a bit of research on UBIFS and something I read from a few
> sources has me confused regarding garbage collection:
> 
> http://osl.sed.hu/~havasi/ubifs/#gc

You should contact Szeged guys and ask them to remove obsolete
information.

For much more up-to-date information, see
http://linux-mtd.infradead.org/doc/ubifs.html#L_documentation

> Looking at the source, I can find the code that does the out of place
> updates, but I can't find any references to in place updates or
> displacement tables. What gives?

We do not have displacement tables, that was some old idea which we
never implemented.

We do not have in-place GC in UBIFS. But we have so-called "in-the-gaps"
method which we use during commit to write the FS index when we do not
have extra empty LEBs. In the code it corresponds to the
'layout_in_gaps()' function.

-- 
Best Regards,
Artem Bityutskiy (Битюцкий Артём)