[sheepdog] [PATCH 3/4 v3] sheep : add new strage type "tree"

[Liu Yuan]

On Fri, Mar 20, 2015 at 06:39:08PM +0900, Saeki Masaki wrote:
> Current sheepdog stores whole objects in single directory like "/var/lib/sheepdog/obj"
> This mechanism is difficult to handle massive files when increasing cluster volume.
> 
> In particular, inode object having special informations about VDI,
> so it is preferable to divide.
> 
> new storage type named "tree"
> It separates the inode object and data object.
> 
> How to use ,
> specify the --store option at the time format
> dog cluster format --store tree
> 
> v2: refactor using common functions for store driver
>     use check_store_type to identify tree store_driver
> 
> v3: rename and little modify function
> 
> Signed-off-by: Masaki Saeki <saeki.masaki at po.ntts.co.jp>
> ---
>  sheep/Makefile.am         |    2 +-
>  sheep/sheep_priv.h        |   21 ++
>  sheep/store/common.c      |    5 +
>  sheep/store/md.c          |   14 +
>  sheep/store/plain_store.c |    1 +
>  sheep/store/tree_store.c  |  758 +++++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 800 insertions(+), 1 deletions(-)
>  create mode 100644 sheep/store/tree_store.c
> 
> diff --git a/sheep/Makefile.am b/sheep/Makefile.am
> index 3ddd761..9dedb03 100644
> --- a/sheep/Makefile.am
> +++ b/sheep/Makefile.am
> @@ -28,7 +28,7 @@ sheep_SOURCES		= sheep.c group.c request.c gateway.c vdi.c \
>  			  journal.c ops.c recovery.c cluster/local.c \
>  			  object_cache.c object_list_cache.c \
>  			  store/common.c store/md.c \
> -			  store/plain_store.c \
> +			  store/plain_store.c store/tree_store.c \
>  			  config.c migrate.c
>  if BUILD_HTTP
> diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
> index e58901f..3f1bf6e 100644
> --- a/sheep/sheep_priv.h
> +++ b/sheep/sheep_priv.h
> @@ -84,6 +84,11 @@ enum REQUST_STATUS {
>  	REQUEST_DROPPED
>  };
> +enum store_id {
> +	PLAIN_STORE,
> +	TREE_STORE
> +};
> +
>  struct request_iocb {
>  	uint32_t count;
>  	int efd;
> @@ -235,6 +240,7 @@ struct vdi_info {
>  struct store_driver {
>  	struct list_node list;
> +	enum store_id id;
>  	const char *name;
>  	int (*init)(void);
>  	bool (*exist)(uint64_t oid, uint8_t ec_index);
> @@ -269,6 +275,20 @@ int default_format(void);
>  int default_remove_object(uint64_t oid, uint8_t ec_index);
>  int default_get_hash(uint64_t oid, uint32_t epoch, uint8_t *sha1);
>  int default_purge_obj(void);
> +
> +int tree_init(void);
> +bool tree_exist(uint64_t oid, uint8_t ec_index);
> +int tree_create_and_write(uint64_t oid, const struct siocb *iocb);
> +int tree_write(uint64_t oid, const struct siocb *iocb);
> +int tree_read(uint64_t oid, const struct siocb *iocb);
> +int tree_link(uint64_t oid, uint32_t tgt_epoch);
> +int tree_update_epoch(uint32_t epoch);
> +int tree_cleanup(void);
> +int tree_format(void);
> +int tree_remove_object(uint64_t oid, uint8_t ec_index);
> +int tree_get_hash(uint64_t oid, uint32_t epoch, uint8_t *sha1);
> +int tree_purge_obj(void);
> +
>  int for_each_object_in_wd(int (*func)(uint64_t, const char *, uint32_t,
>  				      uint8_t, struct vnode_info *, void *),
>  			  bool, void *);
> @@ -404,6 +424,7 @@ void queue_cluster_request(struct request *req);
>  int prepare_iocb(uint64_t oid, const struct siocb *iocb, bool create);
>  int err_to_sderr(const char *path, uint64_t oid, int err);
>  int discard(int fd, uint64_t start, uint32_t end);
> +bool store_id_match(enum store_id id);
>  int update_epoch_log(uint32_t epoch, struct sd_node *nodes, size_t nr_nodes);
>  int inc_and_log_epoch(void);
> diff --git a/sheep/store/common.c b/sheep/store/common.c
> index 8959392..22a915f 100644
> --- a/sheep/store/common.c
> +++ b/sheep/store/common.c
> @@ -102,6 +102,11 @@ int discard(int fd, uint64_t start, uint32_t end)
>  	return ret;
>  }
> +bool store_id_match(enum store_id id)
> +{
> +	return (sd_store->id == id);
> +}
> +
>  int update_epoch_log(uint32_t epoch, struct sd_node *nodes, size_t nr_nodes)
>  {
>  	int ret, len, nodes_len;
> diff --git a/sheep/store/md.c b/sheep/store/md.c
> index 87ab759..09438d8 100644
> --- a/sheep/store/md.c
> +++ b/sheep/store/md.c
> @@ -212,6 +212,20 @@ static int for_each_object_in_path(const char *path,
>  		if (unlikely(!strncmp(d->d_name, ".", 1)))
>  			continue;
> +		/* recursive call for tree store driver sub directories*/
> +		if (store_id_match(TREE_STORE)) {

I just wonder, if store_id_match is necessary since we can check the store
driver by strcmp(name) as your first version. So what is motivation behind
to use store_id_match()?

Thanks,
Yuan