Re: [Yaffs] Disadvantage of using yaffs checkpointing?

Hi Charles,

We have some NAND currently running a old YAFFS driver (with
YAFFS_CHECKPOINT_VERSION 4), and we would like to upgrade to the latest
(with YAFFS_CHECKPOINT_VERSION 7). Will there be any compatible problem and
is there any procedure needs to be taken?

thanks,
Peter
On Tue, May 22, 2012 at 11:36 AM, peterlingoal <peterlingoal@gmail.com>wrote:

> Thanks Charles, the patch works.
>
>
> On Tue, May 22, 2012 at 7:25 AM, Charles Manning <manningc2@actrix.gen.nz>wrote:
>
>> On Tuesday 22 May 2012 10:12:35 Charles Manning wrote:
>> > On Tuesday 22 May 2012 00:31:25 peterlingoal wrote:
>> > > Hi Charles:
>> > >
>> > > following is a proposed patch that check for block state after
>> > > discovering a check point block, and continues search if the block
>> state
>> > > is DEAD: From b08b8c5fc21c2820f66454968be3a5115477fc96 Mon Sep 17
>> > > 00:00:00 2001 From: Peter Lin <peter.lin@gdc-tech.com>
>> > > Date: Mon, 21 May 2012 20:25:55 +0800
>> > > Subject: [PATCH] yaffs: ignore checkpt if it is in bad block
>> > >
>> > > ---
>> > > yaffs_checkptrw.c | 11 +++++++++++
>> > > 1 files changed, 11 insertions(+), 0 deletions(-)
>> > >
>> > > diff --git a/yaffs_checkptrw.c b/yaffs_checkptrw.c
>> > > index 997a618..0d63e74 100644
>> > > --- a/yaffs_checkptrw.c
>> > > +++ b/yaffs_checkptrw.c
>> > > @@ -13,6 +13,8 @@
>> > >
>> > > #include "yaffs_checkptrw.h"
>> > > #include "yaffs_getblockinfo.h"
>> > > +#include "yaffs_nand.h"
>> > > +#include "yaffs_guts.h"
>> > >
>> > > static int yaffs2_checkpt_space_ok(struct yaffs_dev *dev)
>> > > {
>> > > @@ -117,6 +119,15 @@ static void yaffs2_checkpt_find_block(struct
>> > > yaffs_dev *dev)
>> > > tags.ecc_result);
>> > >
>> > > if (tags.seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA) {
>> > > + enum yaffs_block_state state = 0;
>> > > + u32 seq_number = 0;
>> > > + yaffs_query_init_block_state(dev, i, &state, &seq_number);
>> > > + if( YAFFS_BLOCK_STATE_DEAD == state )
>> > > + {
>> > > + yaffs_trace(YAFFS_TRACE_CHECKPOINT,
>> > > + "ignore bad checkpt block %d", i);
>> > > + continue;
>> > > + }
>> >
>> > This approach won't always work
>> > yaffs_querey_init_block_state() applies a block offset which is not set
>> up
>> > properly yet. Instead you need to use the raw functions during
>> checkpoint
>> > reading:
>> >

>> > +                       dev->param.query_block_fn(dev, i, &state, &seq);
>> > +                       if (state == YAFFS_BLOCK_STATE_DEAD)
>> > +                               continue;

>> >
>> > > /* Right kind of block */
>> > > dev->checkpt_next_block = tags.obj_id;
>> > > dev->checkpt_cur_block = i;
>> >
>> > I have a fix for this that should be pushed to yaffs2 git today.
>>
>> Pushed.
>>
>>
>> http://yaffs.net/gitweb?p=yaffs2.git;a=commitdiff;h=d9cae0a277c62c660e4802d3b8745500583273da
>>
>> >
>> > I am also adding a further check to the checkpointing.
>> >
>> > Currently the checkpoint data has various checks in it, but none that
>> > checks for dropped or stale data during the reading. Each checkpoint
>> record
>> > is framed and there is a checksum at the end which do provide a level of
>> > checking.
>> >
>> > I have written some code, now under test, which does further checks on a
>> > chunk-by-chunk basis. This should be checked in today.
>> >
>>
>> This has also been pushed.
>>
>>
>> -- CHarles
>>
>>
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>
>