[Devel] [PATCH 1/3] fs/fuse kio: fix loss of FUSE_FSYNC/FUSE_FLUSH reqs

[Pavel Butsykin]

pls ignore this.

On 03.12.2018 16:02, Pavel Butsykin wrote:
> Fast-Path can loss fsync/flush requests, because PCS_REQ_T_SYNC request set up
> PCS_MAP_FLUSHING flag, but never cleans it. Although initially PCS_MAP_FLUSHING
> flag was created for sync timer, so PCS_REQ_T_SYNC request should ignore
> everything related to PCS_REQ_T_SYNC flag.
> 
> This patch adds timer_sync flag in prepare_map_flush_ireq() to ignore all sync
> timer stuff on PCS_REQ_T_SYNC way.
> 
> Signed-off-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
> ---
>   fs/fuse/kio/pcs/pcs_map.c | 27 ++++++++++++++++-----------
>   1 file changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/fuse/kio/pcs/pcs_map.c b/fs/fuse/kio/pcs/pcs_map.c
> index 459645417462..4bd18c5224ab 100644
> --- a/fs/fuse/kio/pcs/pcs_map.c
> +++ b/fs/fuse/kio/pcs/pcs_map.c
> @@ -2959,20 +2959,24 @@ static void prepare_map_flush_msg(struct pcs_map_entry * m, struct pcs_int_reque
>   	msg->done = sync_done;
>   }
>   
> -static bool valid_for_flush(struct pcs_map_entry *m)
> +static bool valid_for_flush(struct pcs_map_entry *m, bool timer_sync)
>   {
> -	if (m->state & PCS_MAP_DEAD)
> -		return false;
> +	if (timer_sync) {
> +		if (m->state & PCS_MAP_DEAD)
> +			return false;
>   
> +		if (m->flags & PCS_MAP_FLUSHING)
> +			return false;
> +	}
>   	if (!(m->flags & PCS_MAP_DIRTY))
>   		return false;
> -	if (m->flags & PCS_MAP_FLUSHING)
> -		return false;
>   
>   	return true;
>   }
>   
> -static int prepare_map_flush_ireq(struct pcs_map_entry *m, struct pcs_int_request **sreqp)
> +static int prepare_map_flush_ireq(struct pcs_map_entry *m,
> +				  struct pcs_int_request **sreqp,
> +				  bool timer_sync)
>   {
>   	struct pcs_dentry_info *de;
>   	struct pcs_cs_list *cslist;
> @@ -2980,7 +2984,7 @@ static int prepare_map_flush_ireq(struct pcs_map_entry *m, struct pcs_int_reques
>   	struct pcs_msg * msg;
>   
>   	spin_lock(&m->lock);
> -	if (!valid_for_flush(m)) {
> +	if (!valid_for_flush(m, timer_sync)) {
>   		spin_unlock(&m->lock);
>   		return 0;
>   	}
> @@ -3010,7 +3014,7 @@ static int prepare_map_flush_ireq(struct pcs_map_entry *m, struct pcs_int_reques
>   	/* All resources allocated, we need to recheck maps state again */
>   	spin_lock(&m->lock);
>   	cslist_put(cslist);
> -	if (!valid_for_flush(m) || m->cs_list != cslist) {
> +	if (!valid_for_flush(m, timer_sync) || m->cs_list != cslist) {
>   		spin_unlock(&m->lock);
>   		return 0;
>   	}
> @@ -3025,7 +3029,8 @@ static int prepare_map_flush_ireq(struct pcs_map_entry *m, struct pcs_int_reques
>   	sreq->complete_cb = pcs_flushreq_complete;
>   	sreq->flushreq.msg = msg;
>   	FUSE_KTRACE(sreq->cc->fc, "timed FLUSH " MAP_FMT, MAP_ARGS(m));
> -	m->flags |= PCS_MAP_FLUSHING;
> +	if (timer_sync)
> +		m->flags |= PCS_MAP_FLUSHING;
>   	__pcs_map_get(m);
>   	spin_unlock(&m->lock);
>   	*sreqp	= sreq;
> @@ -3047,7 +3052,7 @@ static void sync_timer_work(struct work_struct *w)
>   	struct pcs_int_request * sreq = NULL;
>   	int err;
>   
> -	err = prepare_map_flush_ireq(m, &sreq);
> +	err = prepare_map_flush_ireq(m, &sreq, true);
>   	if (err) {
>   		spin_lock(&m->lock);
>   		if (!(m->state & PCS_MAP_DEAD))
> @@ -3125,7 +3130,7 @@ void map_inject_flush_req(struct pcs_int_request *ireq)
>   				break;
>   			if (!maps[i])
>   				continue;
> -			err = prepare_map_flush_ireq(maps[i], &sreq);
> +			err = prepare_map_flush_ireq(maps[i], &sreq, false);
>   			pcs_map_put(maps[i]);
>   			if (err) {
>   				pcs_set_local_error(&ireq->error, PCS_ERR_NOMEM);
>