[sheepdog] [PATCH v3 2/9] sheep: introduce ledger objects

[Liu Yuan]

On Sun, Feb 23, 2014 at 02:28:21PM +0900, Hitoshi Mitake wrote:
> This introduces ledger objects, which keeps track of the number of
> outstanding references of each generation.  Sheep decrements a
> generational reference count with a gateway request SD_OP_DECREF_OBJ,
> and reclaims objects when there is no generational reference.
> 
> Cc: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> Cc: Valerio Pachera <sirio81 at gmail.com>
> Cc: Alessandro Bolgia <alessandro at extensys.it>
> Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> ---
>  include/internal_proto.h |  2 ++
>  include/sheepdog_proto.h | 28 ++++++++++++++-
>  sheep/gateway.c          |  5 +++
>  sheep/ops.c              | 90 ++++++++++++++++++++++++++++++++++++++++++++++++
>  sheep/sheep_priv.h       |  5 +++
>  sheep/store.c            | 25 ++++++++++++++
>  6 files changed, 154 insertions(+), 1 deletion(-)
> 
> diff --git a/include/internal_proto.h b/include/internal_proto.h
> index 460264c..8582817 100644
> --- a/include/internal_proto.h
> +++ b/include/internal_proto.h
> @@ -99,6 +99,8 @@
>  #define SD_OP_SET_LOGLEVEL	0xBA
>  #define SD_OP_NFS_CREATE	0xBB
>  #define SD_OP_NFS_DELETE	0xBC
> +#define SD_OP_DECREF_OBJ     0xBD
> +#define SD_OP_DECREF_PEER    0xBE
>  
>  /* internal flags for hdr.flags, must be above 0x80 */
>  #define SD_FLAG_CMD_RECOVERY 0x0080
> diff --git a/include/sheepdog_proto.h b/include/sheepdog_proto.h
> index 39d57aa..a1db359 100644
> --- a/include/sheepdog_proto.h
> +++ b/include/sheepdog_proto.h
> @@ -92,6 +92,7 @@
>  #define VMSTATE_BIT (UINT64_C(1) << 62)
>  #define VDI_ATTR_BIT (UINT64_C(1) << 61)
>  #define VDI_BTREE_BIT (UINT64_C(1) << 60)
> +#define LEDGER_BIT (UINT64_C(1) << 59)
>  #define OLD_MAX_DATA_OBJS (1ULL << 20)
>  #define MAX_DATA_OBJS (1ULL << 32)
>  #define MAX_CHILDREN 1024U
> @@ -111,6 +112,7 @@
>  #define SD_INODE_DATA_INDEX_SIZE (sizeof(uint32_t) * SD_INODE_DATA_INDEX)
>  #define SD_INODE_HEADER_SIZE offsetof(struct sd_inode, data_vdi_id)
>  #define SD_ATTR_OBJ_SIZE (sizeof(struct sheepdog_vdi_attr))
> +#define SD_LEDGER_OBJ_SIZE (UINT64_C(1) << 22)
>  #define CURRENT_VDI_ID 0
>  
>  #define STORE_LEN 16
> @@ -164,6 +166,11 @@ struct sd_req {
>  						    /* others mean true */
>  			uint8_t		copy_policy;
>  		} vdi_state;
> +		struct {
> +			uint64_t	oid;
> +			uint32_t	generation;
> +			uint32_t	count;
> +		} ref;
>  
>  		uint32_t		__pad[8];
>  	};
> @@ -401,10 +408,16 @@ static inline bool is_vdi_btree_obj(uint64_t oid)
>  	return !!(oid & VDI_BTREE_BIT);
>  }
>  
> +static inline bool is_ledger_object(uint64_t oid)
> +{
> +	return !!(oid & LEDGER_BIT);
> +}
> +
>  static inline bool is_data_obj(uint64_t oid)
>  {
>  	return !is_vdi_obj(oid) && !is_vmstate_obj(oid) &&
> -		!is_vdi_attr_obj(oid) && !is_vdi_btree_obj(oid);
> +		!is_vdi_attr_obj(oid) && !is_vdi_btree_obj(oid) &&
> +		!is_ledger_object(oid);
>  }
>  
>  static inline size_t count_data_objs(const struct sd_inode *inode)
> @@ -423,6 +436,9 @@ static inline size_t get_objsize(uint64_t oid)
>  	if (is_vdi_btree_obj(oid))
>  		return SD_INODE_DATA_INDEX_SIZE;
>  
> +	if (is_ledger_object(oid))
> +		return SD_LEDGER_OBJ_SIZE;
> +
>  	return SD_DATA_OBJ_SIZE;
>  }
>  
> @@ -473,4 +489,14 @@ static inline __attribute__((used)) void __sd_proto_build_bug_ons(void)
>  	BUILD_BUG_ON(sizeof(struct sd_rsp) != SD_RSP_SIZE);
>  }
>  
> +static inline uint64_t ledger_oid_to_data_oid(uint64_t oid)
> +{
> +	return ~LEDGER_BIT & oid;
> +}
> +
> +static inline uint64_t data_oid_to_ledger_oid(uint64_t oid)
> +{
> +	return LEDGER_BIT | oid;
> +}
> +
>  #endif
> diff --git a/sheep/gateway.c b/sheep/gateway.c
> index f0f716a..bfd3912 100644
> --- a/sheep/gateway.c
> +++ b/sheep/gateway.c
> @@ -648,3 +648,8 @@ int gateway_remove_obj(struct request *req)
>  {
>  	return gateway_forward_request(req);
>  }
> +
> +int gateway_decref_object(struct request *req)
> +{
> +	return gateway_forward_request(req);
> +}
> diff --git a/sheep/ops.c b/sheep/ops.c
> index cc70c8c..660c021 100644
> --- a/sheep/ops.c
> +++ b/sheep/ops.c
> @@ -1037,6 +1037,83 @@ static inline int local_nfs_delete(struct request *req)
>  
>  #endif
>  
> +int peer_decref_object(struct request *req)
> +{
> +	struct sd_req *hdr = &req->rq;
> +	int ret;
> +	uint32_t epoch = hdr->epoch;
> +	uint64_t ledger_oid = hdr->ref.oid;
> +	uint64_t data_oid = ledger_oid_to_data_oid(ledger_oid);
> +	uint32_t generation = hdr->ref.generation;
> +	uint32_t count = hdr->ref.count;
> +	uint32_t *ledger = NULL, *zero = xzalloc(SD_LEDGER_OBJ_SIZE);
> +	bool exist = false, locked = false;
> +	static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

use sd_mutex please

Thanks
Yuan