Re: [PATCH 02/18] lightnvm: pblk: warn when there are opened chunks

["Matias Bjørling" <mb@lightnvm.io>]

On 3/14/19 9:04 AM, Igor Konopko wrote:
> In case of factory pblk init, we might have a situation when there are
> some opened chunks. Based on OCSSD spec we are not allowed to transform
> chunks from the open state directly to the free state, so such a reset
> can lead to IO error (even that most of the controller will allow for
> for such a operation anyway), so we would like to warn users about such
> a situation at least.
> 
> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
> ---
>   drivers/lightnvm/pblk-init.c | 23 ++++++++++++++++-------
>   1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index 1e227a0..b7845f6 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -712,7 +712,7 @@ static int pblk_set_provision(struct pblk *pblk, int nr_free_chks)
>   }
>   
>   static int pblk_setup_line_meta_chk(struct pblk *pblk, struct pblk_line *line,
> -				   struct nvm_chk_meta *meta)
> +				   struct nvm_chk_meta *meta, int *opened)
>   {
>   	struct nvm_tgt_dev *dev = pblk->dev;
>   	struct nvm_geo *geo = &dev->geo;
> @@ -748,6 +748,9 @@ static int pblk_setup_line_meta_chk(struct pblk *pblk, struct pblk_line *line,
>   			continue;
>   		}
>   
> +		if (chunk->state & NVM_CHK_ST_OPEN)
> +			(*opened)++;
> +
>   		if (!(chunk->state & NVM_CHK_ST_OFFLINE))
>   			continue;
>   
> @@ -759,7 +762,7 @@ static int pblk_setup_line_meta_chk(struct pblk *pblk, struct pblk_line *line,
>   }
>   
>   static long pblk_setup_line_meta(struct pblk *pblk, struct pblk_line *line,
> -				 void *chunk_meta, int line_id)
> +				 void *chunk_meta, int line_id, int *opened)
>   {
>   	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>   	struct pblk_line_meta *lm = &pblk->lm;
> @@ -773,7 +776,7 @@ static long pblk_setup_line_meta(struct pblk *pblk, struct pblk_line *line,
>   	line->vsc = &l_mg->vsc_list[line_id];
>   	spin_lock_init(&line->lock);
>   
> -	nr_bad_chks = pblk_setup_line_meta_chk(pblk, line, chunk_meta);
> +	nr_bad_chks = pblk_setup_line_meta_chk(pblk, line, chunk_meta, opened);
>   
>   	chk_in_line = lm->blk_per_line - nr_bad_chks;
>   	if (nr_bad_chks < 0 || nr_bad_chks > lm->blk_per_line ||
> @@ -1019,12 +1022,12 @@ static int pblk_line_meta_init(struct pblk *pblk)
>   	return 0;
>   }
>   
> -static int pblk_lines_init(struct pblk *pblk)
> +static int pblk_lines_init(struct pblk *pblk, bool factory)
>   {
>   	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>   	struct pblk_line *line;
>   	void *chunk_meta;
> -	int nr_free_chks = 0;
> +	int nr_free_chks = 0, nr_opened_chks = 0;
>   	int i, ret;
>   
>   	ret = pblk_line_meta_init(pblk);
> @@ -1059,7 +1062,8 @@ static int pblk_lines_init(struct pblk *pblk)
>   		if (ret)
>   			goto fail_free_lines;
>   
> -		nr_free_chks += pblk_setup_line_meta(pblk, line, chunk_meta, i);
> +		nr_free_chks += pblk_setup_line_meta(pblk, line, chunk_meta, i,
> +							&nr_opened_chks);
>   
>   		trace_pblk_line_state(pblk_disk_name(pblk), line->id,
>   								line->state);
> @@ -1071,6 +1075,11 @@ static int pblk_lines_init(struct pblk *pblk)
>   		goto fail_free_lines;
>   	}
>   
> +	if (factory && nr_opened_chks) {
> +		pblk_warn(pblk, "%d opened chunks during factory creation\n",
> +				nr_opened_chks);
> +	}
> +
>   	ret = pblk_set_provision(pblk, nr_free_chks);
>   	if (ret)
>   		goto fail_free_lines;
> @@ -1235,7 +1244,7 @@ static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
>   		goto fail;
>   	}
>   
> -	ret = pblk_lines_init(pblk);
> +	ret = pblk_lines_init(pblk, flags & NVM_TARGET_FACTORY);
>   	if (ret) {
>   		pblk_err(pblk, "could not initialize lines\n");
>   		goto fail_free_core;
> 

I've going both ways on this one. I think I rather just do an ECN of the 
spec to say that this always have been allowed, and then add a feature 
bit for those that like the reset protection.