mtd/fs/jffs2 nodemgmt.c,1.115,1.116

[Thomas Gleixner]

Hi Estelle,

On Tue, 2005-01-25 at 11:13 +0100, Estelle HAMMACHE wrote:
> Thomas Gleixner wrote:
> > 
> > > - avoid filing blocks on the clean list when they have wasted
> > > space
> > 
> > That's plain wrong.
> > 
> > Wasted space was introduced to prevent endless garbage collection.
> > Wasted space is unreclaimable, because it is less than the minimum node
> > size. It's totally correct to file those blocks on the clean list,
> > because GC _cannot_ reclaim the wasted space.
> 
> Well without this patch I got blocks on the clean list with huge
> wasted space, more than the ISDIRTY calculation, when a write that
> fills exactly the space left in nextblock also obsoletes nodes
> in nextblock (not sure about the exact case it was some time ago).
> In jffs2_mark_node_obsolete, if the node belongs to nextblock, the
> space is always added to wasted_space - not dirty_space. So I don't
> understand whether wasted_space is not what you claim, or it is
> not well implemented.

Things have changed over time, so I'm not sure whether the wasted ->
dirty accounting is still correct all over the place. It was once :)

> I'm afraid my comment in the log was quite misleading: 
> this patch merely prevents filing the block to the clean
> list in jffs2_add_physical_node_ref. As the comment in that
> function says, the block will be filed to the correct list later 
> and with proper ISDIRTY check (or am I missing something ?).

Sorry, I misunderstood the comment. 

Filing the block in jffs2_add_physical_node_ref to the clean list if
appropriate is an optimization. Your check in fact disables the
optimization path as almost all blocks have wasted space. 

Please check !ISDIRTY(jeb->wasted_size) instead of !jeb->wasted_size.

> Lastly, I did submit this patch beforehand to the list, even if it was
> in a thread on NAND failure. I would have expected you to have
> an interest in that thread anyway.

I can not follow 100% of the mail threads all the time.

> (please excuse me if I sound grumpy. Your comments are a bit
> of a cold shower on my newbie enthusiasm. 

I did not intend to slow down your enthusiasm. :)

> If the patch is really a problem I will reverse it tonight.)

Fixing it is ok (see above). 

The coding style violations which dwmw2 pointed out need to be fixed
too.

tglx