Re: [PATCH 7/9] lightnvm: pblk: add l2p crc debug printouts

["Javier González" <jg@lightnvm.io>]

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> On 3 Oct 2017, at 12.05, Hans Holmberg <hans.ml.holmberg@owltronix.com> wrote:
> 
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> Print the CRC of the logical-to-physical mapping during exit and
> after recovering the L2P table to facilitate detection of meta
> data corruption/recovery issues.
> 
> The CRC printed after recovery should match the CRC printed during
> the previous exit - if it doesn't this indicates that either the meta
> data written to the disk is corrupt or recovery failed.
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
> drivers/lightnvm/pblk-init.c | 39 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 34 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index fb41182..c452478 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -76,6 +76,28 @@ static blk_qc_t pblk_make_rq(struct request_queue *q, struct bio *bio)
> 	return BLK_QC_T_NONE;
> }
> 
> +static size_t pblk_trans_map_size(struct pblk *pblk)
> +{
> +	int entry_size = 8;
> +
> +	if (pblk->ppaf_bitsize < 32)
> +		entry_size = 4;
> +
> +	return entry_size * pblk->rl.nr_secs;
> +}
> +
> +#ifdef CONFIG_NVM_DEBUG
> +static u32 pblk_l2p_crc(struct pblk *pblk)
> +{
> +	size_t map_size;
> +	u32 crc = ~(u32)0;
> +
> +	map_size = pblk_trans_map_size(pblk);
> +	crc = crc32_le(crc, pblk->trans_map, map_size);
> +	return crc;
> +}
> +#endif
> +
> static void pblk_l2p_free(struct pblk *pblk)
> {
> 	vfree(pblk->trans_map);
> @@ -85,12 +107,10 @@ static int pblk_l2p_init(struct pblk *pblk)
> {
> 	sector_t i;
> 	struct ppa_addr ppa;
> -	int entry_size = 8;
> -
> -	if (pblk->ppaf_bitsize < 32)
> -		entry_size = 4;
> +	size_t map_size;
> 
> -	pblk->trans_map = vmalloc(entry_size * pblk->rl.nr_secs);
> +	map_size = pblk_trans_map_size(pblk);
> +	pblk->trans_map = vmalloc(map_size);
> 	if (!pblk->trans_map)
> 		return -ENOMEM;
> 
> @@ -508,6 +528,10 @@ static int pblk_lines_configure(struct pblk *pblk, int flags)
> 		}
> 	}
> 
> +#ifdef CONFIG_NVM_DEBUG
> +	pr_info("pblk init: L2P CRC: %x\n", pblk_l2p_crc(pblk));
> +#endif
> +
> 	/* Free full lines directly as GC has not been started yet */
> 	pblk_gc_free_full_lines(pblk);
> 
> @@ -898,6 +922,11 @@ static void pblk_exit(void *private)
> 	down_write(&pblk_lock);
> 	pblk_gc_exit(pblk);
> 	pblk_tear_down(pblk);
> +
> +#ifdef CONFIG_NVM_DEBUG
> +	pr_info("pblk exit: L2P CRC: %x\n", pblk_l2p_crc(pblk));
> +#endif
> +
> 	pblk_free(pblk);
> 	up_write(&pblk_lock);
> }
> --
> 2.7.4

LGTM.

Reviewed-by: Javier González <javier@cnexlabs.com>

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