[Devel] [RFC PATCH vz9 v6 23/62] dm-ploop: make new allocations immediately visible in BAT

[Andrey Zhadchenko]

On 12/5/24 22:55, Alexander Atanasov wrote:
> From: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> 
> We are planning to delay metadata writeback, so we want to
> immediately apply metadata changes to BAT page.
> Make all request that trigger PIWB_TYPE_RELOC apply metadata

Actually should be PIWB_TYPE_ALLOC - my bad :)

> changes immediately.
> 
> https://virtuozzo.atlassian.net/browse/VSTOR-91817
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> ---
>   drivers/md/dm-ploop-map.c | 22 ++++++++++++++--------
>   1 file changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
> index de885049e3f9..eb01eab18019 100644
> --- a/drivers/md/dm-ploop-map.c
> +++ b/drivers/md/dm-ploop-map.c
> @@ -776,6 +776,10 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
>   
>   	dst_clu = piwb->kmpage;
>   
> +	write_lock_irqsave(&md->lock, flags);
> +	if (piwb->type == PIWB_TYPE_ALLOC)
> +		goto skip_apply;
> +
>   	for (; i < last; i++) {
>   		if (piwb->type == PIWB_TYPE_DISCARD) {
>   			ploop_piwb_discard_completed(ploop, success, i + off, dst_clu[i]);
> @@ -785,12 +789,6 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
>   		if (!dst_clu[i])
>   			continue;
>   
> -		if (ploop_cluster_is_in_top_delta(ploop, i + off)
> -						&& piwb->type == PIWB_TYPE_ALLOC) {
> -			WARN_ON(bat_entries[i] != dst_clu[i]);
> -			continue;
> -		}
> -
>   		if (success) {
>   			bat_entries[i] = READ_ONCE(dst_clu[i]);
>   			WRITE_ONCE(md->bat_levels[i], ploop_top_level(ploop));
> @@ -798,11 +796,10 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
>   			ploop_hole_set_bit(i + off, ploop);
>   		}
>   	}
> +skip_apply:
>   
>   	WARN_ON_ONCE(!test_bit(MD_WRITEBACK, &md->status));
>   	clear_bit(MD_WRITEBACK, &md->status);
> -	/* protect piwb */
> -	write_lock_irqsave(&md->lock, flags);
>   	md->piwb = NULL;
>   	write_unlock_irqrestore(&md->lock, flags);
>   
> @@ -1120,6 +1117,8 @@ static int ploop_alloc_cluster(struct ploop *ploop, struct ploop_index_wb *piwb,
>   
>   	to = piwb->kmpage;
>   	WRITE_ONCE(to[clu], *dst_clu);
> +	to = piwb->md->kmpage;
> +	WRITE_ONCE(to[clu], *dst_clu);
>   out:
>   	return ret;
>   }
> @@ -1378,6 +1377,7 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
>   	u32 page_id, clu = cow_pio->clu;
>   	struct ploop_index_wb *piwb;
>   	struct md_page *md;
> +	unsigned long flags;
>   	map_index_t *to;
>   
>   	WARN_ON_ONCE(cow->aux_pio->queue_list_id != PLOOP_LIST_COW);
> @@ -1402,6 +1402,12 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
>   	WARN_ON(to[clu]);
>   	WRITE_ONCE(to[clu], cow->dst_clu);
>   
> +	write_lock_irqsave(&md->lock, flags);
> +	to = md->kmpage;
> +	WRITE_ONCE(to[clu], cow->dst_clu);
> +	WRITE_ONCE(md->bat_levels[clu], ploop_top_level(ploop));
> +	write_unlock_irqrestore(&md->lock, flags);
> +
>   	/* Prevent double clearing of holes_bitmap bit on complete_cow() */
>   	cow->dst_clu = BAT_ENTRY_NONE;
>   	spin_lock_irq(&ploop->deferred_lock);