VFS之文件系统描述

 Linux内核对文件系统类型抽象后的数据结构，每个文件系统都有此类型的一个实例，并且具体

文件系统需要静态定义此类型的对象，然后通过register_filesystem相关接口向系统注册。

或者调用unregister_filesystem()注销。

struct file_system_type { const char *name; int fs_flags;#define FS_REQUIRES_DEV  1 #define FS_BINARY_MOUNTDATA 2#define FS_HAS_SUBTYPE  4#define FS_USERNS_MOUNT  8 /* Can be mounted by userns root */#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */ struct dentry *(*mount) (struct file_system_type *, int,         const char *, void *); void (*kill_sb) (struct super_block *); struct module *owner; struct file_system_type * next; struct hlist_head fs_supers;
 struct lock_class_key s_lock_key; struct lock_class_key s_umount_key; struct lock_class_key s_vfs_rename_key; struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
 struct lock_class_key i_lock_key; struct lock_class_key i_mutex_key; struct lock_class_key i_mutex_dir_key;};