Re: [PATCH 06/18] lightnvm: pblk: recover only written metadata

[Igor Konopko <igor.j.konopko@intel.com>]

On 17.03.2019 00:46, Javier González wrote:
>> On 14 Mar 2019, at 09.04, Igor Konopko <igor.j.konopko@intel.com> wrote:
>>
>> This patch ensures that smeta/emeta was written properly before even
>> trying to read it based on chunk table state and write pointer.
>>
>> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
>> ---
>> drivers/lightnvm/pblk-recovery.c | 43 ++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 41 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
>> index 688fdeb..ba1691d 100644
>> --- a/drivers/lightnvm/pblk-recovery.c
>> +++ b/drivers/lightnvm/pblk-recovery.c
>> @@ -653,8 +653,42 @@ static int pblk_line_was_written(struct pblk_line *line,
>> 	bppa = pblk->luns[smeta_blk].bppa;
>> 	chunk = &line->chks[pblk_ppa_to_pos(geo, bppa)];
>>
>> -	if (chunk->state & NVM_CHK_ST_FREE)
>> -		return 0;
>> +	if (chunk->state & NVM_CHK_ST_CLOSED ||
>> +	    (chunk->state & NVM_CHK_ST_OPEN
>> +	     && chunk->wp >= lm->smeta_sec))
>> +		return 1;
>> +
>> +	return 0;
>> +}
>> +
>> +static int pblk_line_was_emeta_written(struct pblk_line *line,
>> +				       struct pblk *pblk)
>> +{
>> +
>> +	struct pblk_line_meta *lm = &pblk->lm;
>> +	struct nvm_tgt_dev *dev = pblk->dev;
>> +	struct nvm_geo *geo = &dev->geo;
>> +	struct nvm_chk_meta *chunk;
>> +	struct ppa_addr ppa;
>> +	int i, pos;
>> +	int min = pblk->min_write_pgs;
>> +	u64 paddr = line->emeta_ssec;
>> +
>> +	for (i = 0; i < lm->emeta_sec[0]; i++, paddr++) {
>> +		ppa = addr_to_gen_ppa(pblk, paddr, line->id);
>> +		pos = pblk_ppa_to_pos(geo, ppa);
>> +		while (test_bit(pos, line->blk_bitmap)) {
>> +			paddr += min;
>> +			ppa = addr_to_gen_ppa(pblk, paddr, line->id);
>> +			pos = pblk_ppa_to_pos(geo, ppa);
>> +		}
>> +		chunk = &line->chks[pos];
>> +
>> +		if (!(chunk->state & NVM_CHK_ST_CLOSED ||
>> +		    (chunk->state & NVM_CHK_ST_OPEN
>> +		     && chunk->wp > ppa.m.sec)))
>> +			return 0;
>> +	}
>>
>> 	return 1;
>> }
>> @@ -788,6 +822,11 @@ struct pblk_line *pblk_recov_l2p(struct pblk *pblk)
>> 			goto next;
>> 		}
>>
>> +		if (!pblk_line_was_emeta_written(line, pblk)) {
>> +			pblk_recov_l2p_from_oob(pblk, line);
>> +			goto next;
>> +		}
>> +
>> 		if (pblk_line_emeta_read(pblk, line, line->emeta->buf)) {
>> 			pblk_recov_l2p_from_oob(pblk, line);
>> 			goto next;
>> --
>> 2.9.5
> 
>   I would like to avoid iterating on all chunks again an again to check
>   for different things at boot time. What do you think having this as
>   something like PBLK_LINESTATE_OPEN_INVALID or
>   PBLK_LINESTATE_OPEN_NONRECOV, which you populate when collecting the
>   chunk information? Then this becomes a simple check as opposed to the
>   extra chunk iteration?
> 

Ok, will work on sth different.

> On the check itself: Is this done for completeness or have you hit a
> case that is not covered by the smeta/emeta CRC protection?
> 

So generally my goal here was to avoid reading blank sectors if not needed.

>