[Devel] [PATCH RH8 1/2] ploop: Track if we have delta with disable_merge

[Kirill Tkhai]

Vasily, this is for VZ7

On 16.08.2021 12:37, Kirill Tkhai wrote:
> Add a notifier after delta list change, which
> will allow to skip disable merge in next patch.
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  drivers/block/ploop/dev.c   |    7 +++++++
>  include/linux/ploop/ploop.h |   14 ++++++++++++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
> index 0a6c4111ca82..c4cb944358ee 100644
> --- a/drivers/block/ploop/dev.c
> +++ b/drivers/block/ploop/dev.c
> @@ -3519,6 +3519,7 @@ static int ploop_add_delta(struct ploop_device * plo, unsigned long arg)
>  	mutex_lock(&plo->sysfs_mutex);
>  	list_add(&delta->list, &plo->map.delta_list);
>  	mutex_unlock(&plo->sysfs_mutex);
> +	ploop_delta_list_changed(plo);
>  	set_bit(PLOOP_S_CHANGED, &plo->state);
>  
>  	/*
> @@ -3602,6 +3603,7 @@ static int ploop_replace_delta(struct ploop_device * plo, unsigned long arg)
>  
>  	ploop_map_destroy(&plo->map);
>  	list_replace_init(&old_delta->list, &delta->list);
> +	ploop_delta_list_changed(plo);
>  	clear_bit(PLOOP_S_ABORT, &plo->state);
>  
>  	spin_lock_irq(plo->queue->queue_lock);
> @@ -3892,6 +3894,7 @@ static int ploop_snapshot(struct ploop_device * plo, unsigned long arg,
>  		list_add(&delta->list, &plo->map.delta_list);
>  		clear_bit(PLOOP_MAP_IDENTICAL, &plo->map.flags);
>  		mutex_unlock(&plo->sysfs_mutex);
> +		ploop_delta_list_changed(plo);
>  	}
>  	ploop_relax(plo);
>  
> @@ -4010,6 +4013,7 @@ static int ploop_del_delta(struct ploop_device * plo, unsigned long arg)
>  	ploop_quiesce(plo);
>  	next = list_entry(delta->list.next, struct ploop_delta, list);
>  	list_del(&delta->list);
> +	ploop_delta_list_changed(plo);
>  	if (list_empty(&plo->map.delta_list))
>  		plo->cookie[0] = 0;
>  	if (level != 0)
> @@ -4111,6 +4115,7 @@ static void ploop_merge_complete(struct ploop_device * plo,
>  	plo->trans_map = NULL;
>  	plo->maintenance_type = PLOOP_MNTN_OFF;
>  	mutex_unlock(&plo->sysfs_mutex);
> +	ploop_delta_list_changed(plo);
>  	ploop_map_destroy(map);
>  	ploop_relax(plo);
>  }
> @@ -4194,6 +4199,7 @@ static int ploop_merge(struct ploop_device * plo)
>  		plo->trans_map = map;
>  		plo->maintenance_type = PLOOP_MNTN_MERGE;
>  		mutex_unlock(&plo->sysfs_mutex);
> +		ploop_delta_list_changed(plo);
>  	} else {
>  		/* Yes. All transient obstacles must be resolved
>  		 * in prepare_merge. Failed start_merge means
> @@ -4540,6 +4546,7 @@ static void destroy_deltas(struct ploop_device * plo, struct ploop_map * map)
>  		mutex_lock(&plo->sysfs_mutex);
>  		list_del(&delta->list);
>  		mutex_unlock(&plo->sysfs_mutex);
> +		ploop_delta_list_changed(plo);
>  
>  		kobject_del(&delta->kobj);
>  		kobject_put(&plo->kobj);
> diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
> index 2256eb489a97..d0f665796a42 100644
> --- a/include/linux/ploop/ploop.h
> +++ b/include/linux/ploop/ploop.h
> @@ -490,6 +490,7 @@ struct ploop_device
>  	unsigned long		locking_state; /* plo locked by userspace */
>  	unsigned int		fast_path_disabled_count;
>  	unsigned int		discard_disabled_count;
> +	bool			has_disable_merge;
>  };
>  
>  enum
> @@ -650,6 +651,19 @@ static inline struct ploop_delta * map_top_delta(struct ploop_map * map)
>  	return list_first_entry(&map->delta_list, struct ploop_delta, list);
>  }
>  
> +static inline void ploop_delta_list_changed(struct ploop_device *plo)
> +{
> +	bool has_disable_merge = false;
> +	struct ploop_delta *delta;
> +
> +	list_for_each_entry(delta, &plo->map.delta_list, list) {
> +		if (delta->io.ops->disable_merge)
> +			has_disable_merge = true;
> +	}
> +
> +	plo->has_disable_merge = has_disable_merge;
> +}
> +
>  static inline unsigned int cluster_size_in_bytes(struct ploop_device *plo)
>  {
>  	return 1 << (plo->cluster_log + 9);
> 
>