struct  sd_vdi_req {

uint8_t     proto_ver;

uint8_t     opcode;

uint16_t    flags;

uint32_t    epoch;

uint32_t        id;

uint32_t        data_length;

uint64_t    vdi_size; //vdi的大小

uint32_t        base_vdi_id;

uint32_t    copies;

uint32_t        snapid;

uint32_t        pad[3];

};

struct  sd_vdi_rsp {

uint8_t     proto_ver;

uint8_t     opcode;

uint16_t    flags;

uint32_t    epoch;

uint32_t        id;

uint32_t        data_length;

uint32_t        result;

uint32_t        rsvd;

uint32_t        vdi_id;

uint32_t        pad[5];

};

对vdi进行有关操作的请求和响应

struct  sd_so_req {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t   flags;

uint32_t   epoch;

uint32_t        id;

uint32_t        data_length;

uint64_t   oid;

uint64_t   ctime;

uint32_t   copies;

uint32_t   tag;

uint32_t   opcode_specific[2];

};

struct  sd_so_rsp {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t   flags;

uint32_t   epoch;

uint32_t        id;

uint32_t        data_length;

uint32_t        result;

uint32_t   copies;

uint64_t   ctime;

uint64_t   oid;

uint32_t   opcode_specific[2];

};

这对请求和响应的数据结构，对应的opcode为SD_OP_MAKE_FS，对整个集群进行format，并提供copies参数，指定默认的副本的个数；

struct  sd_list_req {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t      flags;

uint32_t      epoch;

uint32_t     id;

uint32_t     data_length;

uint64_t     start; //start_hval

uint64_t     end; //end_hval

uint32_t     tgt_epoch; //epoch参数

uint32_t     pad[3];

};

struct  sd_list_rsp {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t   flags;

uint32_t   epoch;

uint32_t        id;

uint32_t        data_length;

uint32_t        result;

uint32_t        rsvd;

uint64_t        next;

uint32_t        pad[4];

};

主要用于SD_OP_GET_OBJ_LIST操作，获得对应区间上node节点上的object list

struct  sd_node_req {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t      flags;

uint32_t      epoch;

uint32_t     id;

uint32_t     data_length;

uint32_t      request_ver;

uint32_t      pad[7];

};

struct  sd_node_rsp {

uint8_t              proto_ver;

uint8_t              opcode;

uint16_t      flags;

uint32_t      epoch;

uint32_t        id;

uint32_t        data_length;

uint32_t        result;

uint32_t       nr_nodes;

uint32_t       local_idx;

uint32_t       master_idx;

uint64_t       store_size;

uint64_t       store_free;

};

针对SD_OP_STAT_SHEEP和SD_OP_GET_NODE_LIST操作，获得node 详细信息，包括store_size store_free等，或者是获得node list.

struct  sheepdog_inode {

char name[SD_MAX_VDI_LEN];  //vdi的名字

char tag[SD_MAX_VDI_TAG_LEN]; //tag

uint64_t ctime; // create time

uint64_t snap_ctime; //snapshot time

uint64_t vm_clock_nsec;

uint64_t vdi_size; //vdi size

uint64_t vm_state_size;

uint16_t copy_policy;

uint8_t  nr_copies; //副本的个数

uint8_t  block_size_shift; //data object size

uint32_t snap_id; //snapshot of this vdi

uint32_t vdi_id; //vdi id

uint32_t parent_vdi_id;

uint32_t child_vdi_id[MAX_CHILDREN];

uint32_t data_vdi_id[MAX_DATA_OBJS]; //data object id array

};

sheepdog_inode相当于sheep中存储一个镜像文件，都会存在这个结构与之对应，该结构中保存了数据object的id数组，相当与镜像文件的元数据，同时该结构会持久化保存到vid object中；

enum  conn_state {

C_IO_HEADER = 0,

C_IO_DATA_INIT,

C_IO_DATA,

C_IO_END,

C_IO_CLOSED,

};

struct  connection {

int fd;   //sockfd

enum conn_state  c_rx_state; //当前receive状态

int rx_length;

void *rx_buf;

struct sd_req  rx_hdr;

enum conn_state  c_tx_state; //当前transfer状态

int tx_length;

void *tx_buf;

struct sd_rsp  tx_hdr;

};

struct connection结构存储socket连接的状态信息

struct  client_info {

struct connection conn;  //conn state

struct request *rx_req;  //current rx_req

struct request *tx_req;  //current tx_req

struct list_head  reqs;  //client 已经收到的request

struct list_head done_reqs; //已经处理完的request，待发送response

int  refcnt;  //引用计数，request 的个数

};

作为client保存信息，其中conn保存连接状态，reqs代表已经收到的request，done_reqs代表待发送响应的request.

enum cpg_event_type {

CPG_EVENT_CONCHG,

CPG_EVENT_DELIVER,

CPG_EVENT_REQUEST,

};

struct cpg_event {

enum cpg_event_type ctype;

struct list_head cpg_event_list;

unsigned int skip;

};

typedef void (*req_end_t) (struct request *);

struct  request {

struct cpg_event cev;

struct sd_req rq;

struct sd_rsp rp;

void *data;

struct client_info *ci;

struct list_head  r_siblings;  //client_info->reqs

struct list_head  r_wlist;    //client_info->done_reqs

struct list_head  pending_list; //sys->pending_list

uint64_t local_oid[2];

struct sheepdog_node_list_entry  entry[SD_MAX_NODES];

int  nr_nodes;

int  check_consistency;

req_end_t  done;

struct work  work;

};

Server端 请求的详细信息

struct cluster_info {

cpg_handle_t handle;

/* set after finishing the JOIN procedure */

int join_finished;

uint32_t this_nodeid;

uint32_t this_pid;

struct sheepdog_node_list_entry  this_node;

uint32_t epoch;

uint32_t status;

/*

* we add a node to cpg_node_list in confchg then move it to

* sd_node_list when the node joins sheepdog.

*/

struct list_head  cpg_node_list;

struct list_head  sd_node_list;

struct list_head  pending_list;   //未收到响应的request

DECLARE_BITMAP(vdi_inuse, SD_NR_VDIS);

struct list_head  outstanding_req_list;

struct list_head  req_wait_for_obj_list;

struct list_head  consistent_obj_list;

uint32_t  nr_sobjs;  //副本个数

struct list_head  cpg_event_siblings;

struct cpg_event  *cur_cevent;

unsigned long  cpg_event_work_flags;

int  nr_outstanding_io;

int  nr_outstanding_reqs;

uint32_t  recovered_epoch;

};

extern struct cluster_info *sys;

整个集群的信息