[Devel] [RH7 PATCH 1/6] ploop: generalize post_submit stage

[Maxim Patlasov]

On 06/23/2016 10:25 AM, Dmitry Monakhov wrote:
> Currently post_submit() used only for convert_unwritten_extents.
> But post_submit() is good transition point where all submitted
> data was completed by lower layer, and new state about to be processed.
> Iyt is ideal point where we can perform transition actions
> For example:
>   io_direct: Convert unwritten extents
>   io_direct: issue empty barrier bio in order to simulate postflush
>   io_direct,io_kaio: queue to fsync queue
>   Etc.
>
> This patch does not change anything, but prepare post_submit for
> more logic which will be added later.

If we decide to have DEL_FLUSH, I'm OK with this approach. Maybe with 
some renaming:

s/PLOOP_REQ_DEL_FLUSH/PLOOP_REQ_FLUSH_DELAYED
s/PLOOP_REQ_DEL_CONV/PLOOP_REQ_CONV_DELAYED
s/post_submit/pre_process
s/PLOOP_REQ_POST_SUBMIT/PLOOP_REQ_PRE_PROCESS

>
> Signed-off-by: Dmitry Monakhov <dmonakhov at openvz.org>
> ---
>   drivers/block/ploop/dev.c       | 10 ++++++----
>   drivers/block/ploop/io_direct.c | 15 ++++++++++++---
>   include/linux/ploop/ploop.h     | 12 +++++++++++-
>   3 files changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
> index e405232..e8b0304 100644
> --- a/drivers/block/ploop/dev.c
> +++ b/drivers/block/ploop/dev.c
> @@ -2351,10 +2351,12 @@ static void ploop_req_state_process(struct ploop_request * preq)
>   		preq->prealloc_size = 0; /* only for sanity */
>   	}
>   
> -	if (test_bit(PLOOP_REQ_POST_SUBMIT, &preq->state)) {
> -		preq->eng_io->ops->post_submit(preq->eng_io, preq);
> -		clear_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
> +	if (test_and_clear_bit(PLOOP_REQ_POST_SUBMIT, &preq->state)) {
> +		struct ploop_io *io = preq->eng_io;
> +
>   		preq->eng_io = NULL;
> +		if (preq->eng_io->ops->post_submit(io, preq))
> +			goto out;
>   	}
>   
>   restart:
> @@ -2633,7 +2635,7 @@ restart:
>   	default:
>   		BUG();
>   	}
> -
> +out:
>   	if (release_ioc) {
>   		struct io_context * ioc = current->io_context;
>   		current->io_context = saved_ioc;
> diff --git a/drivers/block/ploop/io_direct.c b/drivers/block/ploop/io_direct.c
> index f1812fe..ec905b4 100644
> --- a/drivers/block/ploop/io_direct.c
> +++ b/drivers/block/ploop/io_direct.c
> @@ -416,8 +416,8 @@ try_again:
>   		}
>   
>   		preq->iblock = iblk;
> -		preq->eng_io = io;
> -		set_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
> +		set_bit(PLOOP_REQ_DEL_CONV, &preq->state);
> +		ploop_add_post_submit(io, preq);
>   		dio_submit_pad(io, preq, sbl, size, em);
>   		err = 0;
>   		goto end_write;
> @@ -501,7 +501,7 @@ end_write:
>   }
>   
>   static void
> -dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
> +dio_convert_extent(struct ploop_io *io, struct ploop_request * preq)
>   {
>   	struct ploop_device *plo = preq->plo;
>   	sector_t sec = (sector_t)preq->iblock << preq->plo->cluster_log;
> @@ -540,6 +540,15 @@ dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
>   	}
>   }
>   
> +static int
> +dio_post_submit(struct ploop_io *io, struct ploop_request * preq)
> +{
> +	if (test_and_clear_bit(PLOOP_REQ_DEL_CONV, &preq->state))
> +		dio_convert_extent(io, preq);
> +
> +	return 0;
> +}
> +
>   /* Submit the whole cluster. If preq contains only partial data
>    * within the cluster, pad the rest of cluster with zeros.
>    */
> diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
> index 0fba25e..4c52a40 100644
> --- a/include/linux/ploop/ploop.h
> +++ b/include/linux/ploop/ploop.h
> @@ -148,7 +148,7 @@ struct ploop_io_ops
>   			  struct bio_list *sbl, iblock_t iblk, unsigned int size);
>   	void	(*submit_alloc)(struct ploop_io *, struct ploop_request *,
>   				struct bio_list *sbl, unsigned int size);
> -	void	(*post_submit)(struct ploop_io *, struct ploop_request *);
> +	int (*post_submit)(struct ploop_io *, struct ploop_request *);
>   
>   	int	(*disable_merge)(struct ploop_io * io, sector_t isector, unsigned int len);
>   	int	(*fastmap)(struct ploop_io * io, struct bio *orig_bio,
> @@ -471,6 +471,7 @@ enum
>   	PLOOP_REQ_POST_SUBMIT, /* preq needs post_submit processing */
>   	PLOOP_REQ_PUSH_BACKUP, /* preq was ACKed by userspace push_backup */
>   	PLOOP_REQ_ALLOW_READS, /* READs are allowed for given req_cluster */
> +	PLOOP_REQ_DEL_CONV,    /* post_submit: conversion required */
>   	PLOOP_REQ_FSYNC_DONE,  /* fsync_thread() performed f_op->fsync() */
>   };
>   
> @@ -479,6 +480,8 @@ enum
>   #define PLOOP_REQ_RELOC_S_FL (1 << PLOOP_REQ_RELOC_S)
>   #define PLOOP_REQ_DISCARD_FL (1 << PLOOP_REQ_DISCARD)
>   #define PLOOP_REQ_ZERO_FL (1 << PLOOP_REQ_ZERO)
> +#define PLOOP_REQ_POST_SUBMIT_FL (1 << PLOOP_REQ_POST_SUBMIT)
> +#define PLOOP_REQ_DEL_CONV_FL (1 << PLOOP_REQ_DEL_CONV)
>   
>   enum
>   {
> @@ -767,6 +770,13 @@ static inline void ploop_entry_qlen_dec(struct ploop_request * preq)
>   		preq->plo->read_sync_reqs--;
>   	}
>   }
> +static inline
> +void ploop_add_post_submit(struct ploop_io *io, struct ploop_request * preq)
> +{
> +	BUG_ON(preq->eng_io && preq->eng_io != io);
> +	preq->eng_io = io;
> +	set_bit(PLOOP_REQ_POST_SUBMIT, &preq->state);
> +}
>   
>   static inline int ploop_map_log(struct ploop_device *plo)
>   {