Re: [PATCH 11/14] bcache: initialize bcache journal for NVDIMM meta device

[Hannes Reinecke <hare@suse.de>]

On 6/15/21 7:49 AM, Coly Li wrote:
> The nvm-pages allocator may store and index the NVDIMM pages allocated
> for bcache journal. This patch adds the initialization to store bcache
> journal space on NVDIMM pages if BCH_FEATURE_INCOMPAT_NVDIMM_META bit is
> set by bcache-tools.
> 
> If BCH_FEATURE_INCOMPAT_NVDIMM_META is set, get_nvdimm_journal_space()
> will return the linear address of NVDIMM pages for bcache journal,
> - If there is previously allocated space, find it from nvm-pages owner
>   list and return to bch_journal_init().
> - If there is no previously allocated space, require a new NVDIMM range
>   from the nvm-pages allocator, and return it to bch_journal_init().
> 
> And in bch_journal_init(), keys in sb.d[] store the corresponding linear
> address from NVDIMM into sb.d[i].ptr[0] where 'i' is the bucket index to
> iterate all journal buckets.
> 
> Later when bcache journaling code stores the journaling jset, the target
> NVDIMM linear address stored (and updated) in sb.d[i].ptr[0] can be used
> directly in memory copy from DRAM pages into 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 | 105 ++++++++++++++++++++++++++++++++++++
>  drivers/md/bcache/journal.h |   2 +-
>  drivers/md/bcache/super.c   |  16 +++---
>  3 files changed, 115 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
> index 61bd79babf7a..32599d2ff5d2 100644
> --- a/drivers/md/bcache/journal.c
> +++ b/drivers/md/bcache/journal.c
> @@ -9,6 +9,8 @@
>  #include "btree.h"
>  #include "debug.h"
>  #include "extents.h"
> +#include "nvm-pages.h"
> +#include "features.h"
>  
>  #include <trace/events/bcache.h>
>  
> @@ -982,3 +984,106 @@ int bch_journal_alloc(struct cache_set *c)
>  
>  	return 0;
>  }
> +
> +#if defined(CONFIG_BCACHE_NVM_PAGES)
> +
> +static void *find_journal_nvm_base(struct bch_nvm_pages_owner_head *owner_list,
> +				   struct cache *ca)
> +{
> +	unsigned long addr = 0;
> +	struct bch_nvm_pgalloc_recs *recs_list = owner_list->recs[0];
> +
> +	while (recs_list) {
> +		struct bch_pgalloc_rec *rec;
> +		unsigned long jnl_pgoff;
> +		int i;
> +
> +		jnl_pgoff = ((unsigned long)ca->sb.d[0]) >> PAGE_SHIFT;
> +		rec = recs_list->recs;
> +		for (i = 0; i < recs_list->used; i++) {
> +			if (rec->pgoff == jnl_pgoff)
> +				break;
> +			rec++;
> +		}
> +		if (i < recs_list->used) {
> +			addr = rec->pgoff << PAGE_SHIFT;
> +			break;
> +		}
> +		recs_list = recs_list->next;
> +	}
> +	return (void *)addr;
> +}
> +
> +static void *get_nvdimm_journal_space(struct cache *ca)
> +{
> +	struct bch_nvm_pages_owner_head *owner_list = NULL;
> +	void *ret = NULL;
> +	int order;
> +
> +	owner_list = bch_get_allocated_pages(ca->sb.set_uuid);
> +	if (owner_list) {
> +		ret = find_journal_nvm_base(owner_list, ca);
> +		if (ret)
> +			goto found;
> +	}
> +
> +	order = ilog2(ca->sb.bucket_size *
> +		      ca->sb.njournal_buckets / PAGE_SECTORS);
> +	ret = bch_nvm_alloc_pages(order, ca->sb.set_uuid);
> +	if (ret)
> +		memset(ret, 0, (1 << order) * PAGE_SIZE);
> +
> +found:
> +	return ret;
> +}
> +
> +static int __bch_journal_nvdimm_init(struct cache *ca)
> +{
> +	int i, ret = 0;
> +	void *journal_nvm_base = NULL;
> +
> +	journal_nvm_base = get_nvdimm_journal_space(ca);
> +	if (!journal_nvm_base) {
> +		pr_err("Failed to get journal space from nvdimm\n");
> +		ret = -1;
> +		goto out;
> +	}
> +
> +	/* Iniialized and reloaded from on-disk super block already */
> +	if (ca->sb.d[0] != 0)
> +		goto out;
> +
> +	for (i = 0; i < ca->sb.keys; i++)
> +		ca->sb.d[i] =
> +			(u64)(journal_nvm_base + (ca->sb.bucket_size * i));
> +
> +out:
> +	return ret;
> +}
> +
> +#else /* CONFIG_BCACHE_NVM_PAGES */
> +
> +static int __bch_journal_nvdimm_init(struct cache *ca)
> +{
> +	return -1;
> +}
> +
> +#endif /* CONFIG_BCACHE_NVM_PAGES */
> +
> +int bch_journal_init(struct cache_set *c)
> +{
> +	int i, ret = 0;
> +	struct cache *ca = c->cache;
> +
> +	ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
> +				2, SB_JOURNAL_BUCKETS);
> +
> +	if (!bch_has_feature_nvdimm_meta(&ca->sb)) {
> +		for (i = 0; i < ca->sb.keys; i++)
> +			ca->sb.d[i] = ca->sb.first_bucket + i;
> +	} else {
> +		ret = __bch_journal_nvdimm_init(ca);
> +	}
> +
> +	return ret;
> +}
> diff --git a/drivers/md/bcache/journal.h b/drivers/md/bcache/journal.h
> index f2ea34d5f431..e3a7fa5a8fda 100644
> --- a/drivers/md/bcache/journal.h
> +++ b/drivers/md/bcache/journal.h
> @@ -179,7 +179,7 @@ void bch_journal_mark(struct cache_set *c, struct list_head *list);
>  void bch_journal_meta(struct cache_set *c, struct closure *cl);
>  int bch_journal_read(struct cache_set *c, struct list_head *list);
>  int bch_journal_replay(struct cache_set *c, struct list_head *list);
> -
> +int bch_journal_init(struct cache_set *c);
>  void bch_journal_free(struct cache_set *c);
>  int bch_journal_alloc(struct cache_set *c);
>  
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index ce22aefb1352..cce0f6bf0944 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -147,10 +147,15 @@ static const char *read_super_common(struct cache_sb *sb,  struct block_device *
>  		goto err;
>  
>  	err = "Journal buckets not sequential";
> +#if defined(CONFIG_BCACHE_NVM_PAGES)
> +	if (!bch_has_feature_nvdimm_meta(sb)) {
> +#endif
>  	for (i = 0; i < sb->keys; i++)
>  		if (sb->d[i] != sb->first_bucket + i)
>  			goto err;
> -
> +#ifdef CONFIG_BCACHE_NVM_PAGES
> +	} /* bch_has_feature_nvdimm_meta */
> +#endif
>  	err = "Too many journal buckets";
>  	if (sb->first_bucket + sb->keys > sb->nbuckets)
>  		goto err;

Extremely awkward.
Make 'bch_has_feature_nvdimm_meta()' generally available, and have it
return 'false' if the config feature isn't enabled.

> @@ -2072,14 +2077,11 @@ static int run_cache_set(struct cache_set *c)
>  		if (bch_journal_replay(c, &journal))
>  			goto err;
>  	} else {
> -		unsigned int j;
> -
>  		pr_notice("invalidating existing data\n");
> -		ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
> -					2, SB_JOURNAL_BUCKETS);
>  
> -		for (j = 0; j < ca->sb.keys; j++)
> -			ca->sb.d[j] = ca->sb.first_bucket + j;
> +		err = "error initializing journal";
> +		if (bch_journal_init(c))
> +			goto err;
>  
>  		bch_initial_gc_finish(c);
>  
> 
Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer