UBIFS分析二重要结构体.docVIP

UBIFS中的重要的结构体 用leeming的话来说，一个大的工程中，最最核心的往往是数据结构体的定义。所以看代码不急着看c文件，而是主要看document和h文件，来理解设计者的思路，这样才能走对路。 1. struct ubi_device UBI中对于一个UBI设备的抽象是以struct ubi_device来定义，其中包括了该UBI设备的各种信息。 struct ubi_device { struct cdev cdev; struct device dev; int ubi_num;//UBI设备的标号，在ubiattach用户程序时以-d选项来输入 char ubi_name[sizeof(UBI_NAME_STR)+5];//ubi设备的名称 int vol_count;//在该UBI设备中有多少个volume struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT]; spinlock_t volumes_lock; int ref_count; int image_seq; int rsvd_pebs;//保留的LEB数目 int avail_pebs;//可用的LEB数目 int beb_rsvd_pebs;//为坏块处理而保留的LEB数目 int beb_rsvd_level;//为坏块处理而保留的LEB的正常数目 int autoresize_vol_id; int vtbl_slots; int vtbl_size;//volume表的大小（bytes） struct ubi_vtbl_record *vtbl;//内存中volume表的拷贝 struct mutex device_mutex; int max_ec;//最大的erase counter /* Note, mean_ec is not updated run-time - should be fixed */ int mean_ec;//平均erase counter /* EBA sub-systems stuff */ unsigned long long global_sqnum; spinlock_t ltree_lock; struct rb_root ltree; struct mutex alc_mutex; /* Wear-leveling sub-systems stuff */ struct rb_root used;//一个红黑树，其中是已用的blcok struct rb_root erroneous;// RB-tree of erroneous used physical eraseblocks struct rb_root free;//红黑树的根，其中是没有用到的block struct rb_root scrub;//需要擦除的blcok struct list_head pq[UBI_PROT_QUEUE_LEN]; int pq_head; spinlock_t wl_lock; struct mutex move_mutex; struct rw_semaphore work_sem; int wl_scheduled; struct ubi_wl_entry **lookuptbl;// a table to quickly find a struct ubi_wl_entry object for any physical eraseblock,，一个struct ubi_wl_entry类型的数组，以pnum为下标，记录该UBI设备的每一个block struct ubi_wl_entry *move_from;// physical eraseblock from where the data is being moved struct ubi_wl_entry *move_to;// physical eraseblock where the data is being moved to int move_to_put;//标志位，用于标志目的LEB是否被put struct list_head works;// list of pending works int works_count;// count of pending works struct task_struct *bgt_thread;//UBI的后台进程 int thread_enabled; char bgt_name[sizeof(UBI_BGT_NAM