Re: [Yaffs] power cycle during rm

Hi All

I'm looking at fixing the root problem, but for now you can modify the line
maxCopies = (wholeBlock) ? dev->nChunksPerBlock : 10;
to
maxCopies = (1 || wholeBlock) ? dev->nChunksPerBlock : 10;

That will force a whole block gc.

I would not force agressive gc as that causes more impact.

-- CHarles



On Monday 08 June 2009 15:05:05 Rong Shen wrote:
> On Sun, Jun 7, 2009 at 8:50 PM, Babrian Viktor<v@renyi.hu> wrote:
> > Hi again,
> >
> > my last questions:
> > - Is it OK to use aggressive garbage collection only? It cleanly solves
> > the issue for me. (my understanding is that it might be slower but it
> > won't do any harm)
> > - is it possible that the root cause of the problem is in some
> > underlaying layer (e.g. nand driver?) Under what circumstances can it
> > happen that the
>
> It looks more like a yaffs2 bug as you have pointed out. softDeletions
> shouldn't be subtracted from nFreeChunks if the block is not fully
> claimed.
>
> > softDeletions of a block gets to the maximum value? Can an interrupted
> > erase
>
> Maximum values, i.e. number of chunks (pages) per block gets maximum,
> in your case 64, when all chunks are soft deleted.
>
> > cause this? And whose responsibility is it to ensure that this does not
>
> hmmm...
>
> > happen? Is it a yaffs issue or nand flash driver issue?
> >
> > Thanks,
> > Viktor Babrian
>
> Rong
>
> > On Fri, 29 May 2009, Babrian Viktor wrote:
> >> Date: Fri, 29 May 2009 16:25:28 +0200 (CEST)
> >> From: Babrian Viktor <v@renyi.hu>
> >> To: yaffs@lists.aleph1.co.uk
> >> Subject: Re: [Yaffs] power cycle during rm
> >>
> >> Hi,
> >>
> >> the reason why yaffs_GarbageCollectBlock() performs the row:
> >> dev->nFreeChunks -= bi->softDeletions;
> >> 7 times for each block is that yaffs_GarbageCollectBlock() is called
> >> with wholeBlock = 0 and therefore it deals with only 10 chunks of the
> >> block every time it is called (maxCopies = (wholeBlock) ?
> >> dev->nChunksPerBlock : 10). WHen deleting the last chunk of the block,
> >> the block is marked dirty and it gets out from the 'collecting' state
> >> and from that point
> >> yaffs_GarbageCollectBlock() is not called anymore with that given
> >> blocknumber. There are 64 chunks in each block and 64/10 gives 7.
> >> Now something is obviously wrong here.
> >> There are several solutions I see but I do not know the sideeffects of.
> >> Calling yaffs_GarbageCollectBlock() with wholeBlock = 1 only seems to
> >> solve the situation but there must be better solution than that.
> >> Performing the subtraction of bi->softDeletions only at the end of the
> >> function (when the block is not in collecting state) could also work but
> >> it is unclear to me if it leads to unconsistency or anything. I also do
> >> not know why the softDeletions of the given block is 64 - does that seem
> >> correct anyway?
> >>
> >> Please at least confirm whether this hack is OK - I need to make file
> >> operations as reliable as possible. Any other solutions are welcome of
> >> course.
> >>
> >> Thanks in advance,
> >> Viktor Babrian
> >>
> >>
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