ext2文件系统源代码之ext2.h

今天，我们看一下ext2文件系统源代码里面的ext2.h文件，这是一个头文件，里边都是一些函数的声明和一些结构体的定义，很多引用ext2的函数的地方都需要包含这个头文件，所以这个头文件用处是很广泛的，但是这个文件很简单，并且还很短，这就让我们理解变得很轻松了。

#include <linux/fs.h>#include <linux/ext2_fs.h>/*ext2挂载选项结构体*/struct ext2_mount_options {/*挂载选项位图*/unsigned long s_mount_opt;/*保存用户id和保存组id*/uid_t s_resuid;gid_t s_resgid;};/*在内存里的ext2文件系统的inode信息数据*/struct ext2_inode_info {__le32i_data[15];__u32i_flags;__u32i_faddr;__u8i_frag_no;__u8i_frag_size;__u16i_state;__u32i_file_acl;__u32i_dir_acl;__u32i_dtime;/*i_block_group是这个文件的inode所在的块组号码，ext2文件系统分配block的时候尽量使得block和他的inode在一个块组，分配inode的时候尽量使得inode和它的父目录的inode在一个块组 */__u32i_block_group;/*i_next_alloc_block记录最近分配的块的逻辑编号，这个名字取得不是很好 */__u32i_next_alloc_block;/*i_next_alloc_goal记录最近分配的块的物理编号，这个变量给了我们下一次分配的优先位置*/__u32i_next_alloc_goal;__u32i_prealloc_block;__u32i_prealloc_count;__u32i_dir_start_lookup;/*配置了CONFIG_EXT2_FS_XATTR宏才会有的属性操作的信号量*/#ifdef CONFIG_EXT2_FS_XATTRstruct rw_semaphore xattr_sem;#endif/*配置了CONFIG_EXT2_FS_POSIX_ACL宏才会有的属性操作的acl操作结构体，之前讲过的哦*/#ifdef CONFIG_EXT2_FS_POSIX_ACLstruct posix_acl*i_acl;struct posix_acl*i_default_acl;#endifrwlock_t i_meta_lock;/*我们一般用到的inode结构体就是这个*/struct inodevfs_inode;};/*ext2的标记位，这个标识ext2刚刚建立*/#define EXT2_STATE_NEW0x00000001 /* inode is newly created *//*从inode结构体获得ext2_inode_info的函数，直接通过container_of宏，上边我们刚讲过，vfs_inode就是此处的inode*/static inline struct ext2_inode_info *EXT2_I(struct inode *inode){return container_of(inode, struct ext2_inode_info, vfs_inode);}/* balloc.c的函数声明，我们都讲过的哦 */extern int ext2_bg_has_super(struct super_block *sb, int group);extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);extern int ext2_new_block (struct inode *, unsigned long,   __u32 *, __u32 *, int *);extern void ext2_free_blocks (struct inode *, unsigned long,      unsigned long);extern unsigned long ext2_count_free_blocks (struct super_block *);extern unsigned long ext2_count_dirs (struct super_block *);extern void ext2_check_blocks_bitmap (struct super_block *);extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,    unsigned int block_group,    struct buffer_head ** bh);/* dir.c的函数声明，我们都讲过的哦 */extern int ext2_add_link (struct dentry *, struct inode *);extern ino_t ext2_inode_by_name(struct inode *, struct dentry *);extern int ext2_make_empty(struct inode *, struct inode *);extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct dentry *, struct page **);extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);extern int ext2_empty_dir (struct inode *);extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *);/* fsync.c 的函数声明*/extern int ext2_sync_file (struct file *, struct dentry *, int);/* ialloc.c的函数声明 */extern struct inode * ext2_new_inode (struct inode *, int);extern void ext2_free_inode (struct inode *);extern unsigned long ext2_count_free_inodes (struct super_block *);extern void ext2_check_inodes_bitmap (struct super_block *);extern unsigned long ext2_count_free (struct buffer_head *, unsigned);/* inode.c的函数声明 */extern void ext2_read_inode (struct inode *);extern int ext2_write_inode (struct inode *, int);extern void ext2_put_inode (struct inode *);extern void ext2_delete_inode (struct inode *);extern int ext2_sync_inode (struct inode *);extern void ext2_discard_prealloc (struct inode *);extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);extern void ext2_truncate (struct inode *);extern int ext2_setattr (struct dentry *, struct iattr *);extern void ext2_set_inode_flags(struct inode *inode);extern void ext2_get_inode_flags(struct ext2_inode_info *);/* ioctl.c的函数声明 */extern int ext2_ioctl (struct inode *, struct file *, unsigned int,       unsigned long);extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);/* namei.c的函数声明 */struct dentry *ext2_get_parent(struct dentry *child);/* super.c的函数声明 */extern void ext2_error (struct super_block *, const char *, const char *, ...)__attribute__ ((format (printf, 3, 4)));extern void ext2_warning (struct super_block *, const char *, const char *, ...)__attribute__ ((format (printf, 3, 4)));extern void ext2_update_dynamic_rev (struct super_block *sb);extern void ext2_write_super (struct super_block *);/* * Inodes和files结构体的函数操作结构体集合 *//* dir.c文件里的*/extern const struct file_operations ext2_dir_operations;/* file.c文件里的 */extern const struct inode_operations ext2_file_inode_operations;extern const struct file_operations ext2_file_operations;extern const struct file_operations ext2_xip_file_operations;/* inode.c文件里的 */extern const struct address_space_operations ext2_aops;extern const struct address_space_operations ext2_aops_xip;extern const struct address_space_operations ext2_nobh_aops;/* namei.c文件里的 */extern const struct inode_operations ext2_dir_inode_operations;extern const struct inode_operations ext2_special_inode_operations;/* symlink.c文件里的 */extern const struct inode_operations ext2_fast_symlink_inode_operations;extern const struct inode_operations ext2_symlink_inode_operations;