Re: [Yaffs] power cycle during rm

On Tuesday 09 June 2009 11:11:54 Charles Manning wrote:
> 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.

or even simpler... Set
wholeBlock = 1;
near the top of yaffs_GarbageCollectBlock();

>
> 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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