Re: [PATCH 13/14] bcache: read jset from NVDIMM pages for journal replay

[Coly Li <colyli@suse.de>]

On 6/22/21 7:04 PM, Hannes Reinecke wrote:
> On 6/15/21 7:49 AM, Coly Li wrote:
>> This patch implements two methods to read jset from media for journal
>> replay,
>> - __jnl_rd_bkt() for block device
>>   This is the legacy method to read jset via block device interface.
>> - __jnl_rd_nvm_bkt() for NVDIMM
>>   This is the method to read jset from NVDIMM memory interface, a.k.a
>>   memcopy() from NVDIMM pages to DRAM pages.
>>
>> If BCH_FEATURE_INCOMPAT_NVDIMM_META is set in incompat feature set,
>> during running cache set, journal_read_bucket() will read the journal
>> content from NVDIMM by __jnl_rd_nvm_bkt(). The linear addresses of
>> NVDIMM pages to read jset are stored in sb.d[SB_JOURNAL_BUCKETS], which
>> were initialized and maintained in previous runs of the cache set.
>>
>> A thing should be noticed is, when bch_journal_read() is called, the
>> linear address of NVDIMM pages is not loaded and initialized yet, it
>> is necessary to call __bch_journal_nvdimm_init() before reading the jset
>> from NVDIMM pages.
>>
>> Signed-off-by: Coly Li <colyli@suse.de>
>> Cc: Jianpeng Ma <jianpeng.ma@intel.com>
>> Cc: Qiaowei Ren <qiaowei.ren@intel.com>
>> ---
>>  drivers/md/bcache/journal.c | 93 +++++++++++++++++++++++++++----------
>>  1 file changed, 69 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
>> index 03ecedf813b0..23e5ccf125df 100644
>> --- a/drivers/md/bcache/journal.c
>> +++ b/drivers/md/bcache/journal.c
>> @@ -34,60 +34,96 @@ static void journal_read_endio(struct bio *bio)
>>  	closure_put(cl);
>>  }
>>  
>> +static struct jset *__jnl_rd_bkt(struct cache *ca, unsigned int bkt_idx,
>> +				    unsigned int len, unsigned int offset,
>> +				    struct closure *cl)
>> +{
>> +	sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bkt_idx]);
>> +	struct bio *bio = &ca->journal.bio;
>> +	struct jset *data = ca->set->journal.w[0].data;
>> +
>> +	bio_reset(bio);
>> +	bio->bi_iter.bi_sector	= bucket + offset;
>> +	bio_set_dev(bio, ca->bdev);
>> +	bio->bi_iter.bi_size	= len << 9;
>> +	bio->bi_end_io	= journal_read_endio;
>> +	bio->bi_private = cl;
>> +	bio_set_op_attrs(bio, REQ_OP_READ, 0);
>> +	bch_bio_map(bio, data);
>> +
>> +	closure_bio_submit(ca->set, bio, cl);
>> +	closure_sync(cl);
>> +
>> +	/* Indeed journal.w[0].data */
>> +	return data;
>> +}
>> +
>> +#if defined(CONFIG_BCACHE_NVM_PAGES)
>> +
>> +static struct jset *__jnl_rd_nvm_bkt(struct cache *ca, unsigned int bkt_idx,
>> +				     unsigned int len, unsigned int offset)
>> +{
>> +	void *jset_addr = (void *)ca->sb.d[bkt_idx] + (offset << 9);
>> +	struct jset *data = ca->set->journal.w[0].data;
>> +
>> +	memcpy(data, jset_addr, len << 9);
>> +
>> +	/* Indeed journal.w[0].data */
>> +	return data;
>> +}
>> +
>> +#else /* CONFIG_BCACHE_NVM_PAGES */
>> +
>> +static struct jset *__jnl_rd_nvm_bkt(struct cache *ca, unsigned int bkt_idx,
>> +				     unsigned int len, unsigned int offset)
>> +{
>> +	return NULL;
>> +}
>> +
>> +#endif /* CONFIG_BCACHE_NVM_PAGES */
>> +
>>  static int journal_read_bucket(struct cache *ca, struct list_head *list,
>> -			       unsigned int bucket_index)
>> +			       unsigned int bucket_idx)
> This renaming is pointless.

Copied, will revert this in next post.

Thanks for your review.

Coly Li