Linux内核中从inode结构得到文件路径名

struct file_operations {
	struct module *owner;
	loff_t (*llseek) (struct file *, loff_t, int);
	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
	ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
	ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
	int (*readdir) (struct file *, void *, filldir_t);
	unsigned int (*poll) (struct file *, struct poll_table_struct *);
	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
	int (*mmap) (struct file *, struct vm_area_struct *);
	int (*open) (struct inode *, struct file *);
	int (*flush) (struct file *, fl_owner_t id);
	int (*release) (struct inode *, struct file *);
	int (*fsync) (struct file *, loff_t, loff_t, int datasync);
	int (*aio_fsync) (struct kiocb *, int datasync);
	int (*fasync) (int, struct file *, int);
	int (*lock) (struct file *, int, struct file_lock *);
	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
	int (*check_flags)(int);
	int (*flock) (struct file *, int, struct file_lock *);
	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
	int (*setlease)(struct file *, long, struct file_lock **);
	long (*fallocate)(struct file *file, int mode, loff_t offset,
			  loff_t len);
};

struct files_struct {
  /*
   * read mostly part
   */
	atomic_t count;
	struct fdtable __rcu *fdt;
	struct fdtable fdtab;
  /*
   * written part on a separate cache line in SMP
   */
	spinlock_t file_lock ____cacheline_aligned_in_smp;
	int next_fd;
	struct embedded_fd_set close_on_exec_init;
	struct embedded_fd_set open_fds_init;
	struct file __rcu * fd_array[NR_OPEN_DEFAULT];
};

struct dentry {
	/* RCU lookup touched fields */
	unsigned int d_flags;		/* protected by d_lock */
	seqcount_t d_seq;		/* per dentry seqlock */
	struct hlist_bl_node d_hash;	/* lookup hash list */
	struct dentry *d_parent;	/* parent directory */
	struct qstr d_name;
	struct inode *d_inode;		/* Where the name belongs to - NULL is
					 * negative */
	unsigned char d_iname[DNAME_INLINE_LEN];	/* small names */

	/* Ref lookup also touches following */
	unsigned int d_count;		/* protected by d_lock */
	spinlock_t d_lock;		/* per dentry lock */
	const struct dentry_operations *d_op;
	struct super_block *d_sb;	/* The root of the dentry tree */
	unsigned long d_time;		/* used by d_revalidate */
	void *d_fsdata;			/* fs-specific data */

	struct list_head d_lru;		/* LRU list */
	/*
	 * d_child and d_rcu can share memory
	 */
	union {
		struct list_head d_child;	/* child of parent list */
	 	struct rcu_head d_rcu;
	} d_u;
	struct list_head d_subdirs;	/* our children */
	struct list_head d_alias;	/* inode alias list */
};

char *getfullpath(struct inode *inod,char* buffer,int len)
{
	struct list_head* plist = NULL;
	struct dentry* tmp = NULL;
	struct dentry* dent = NULL;
	struct dentry* parent = NULL;
	char* name = NULL;
	char* pbuf = buffer + PATH_MAX - 1;
	struct inode* pinode = inod;
	int length = 0;

	buffer[PATH_MAX - 1] = '\0';
	if(pinode == NULL)
		return NULL;
	list_for_each(plist,&pinode->i_dentry)
	{
		tmp = list_entry(plist,struct dentry,d_alias);
		if(tmp->d_inode == pinode)
		{
			dent = tmp;
			break;
		}
	}
	if(dent == NULL)
	{
		return NULL;
	}
	name = (char*)(dent->d_name.name);
	name = name + strlen(name) - 4;
	if(!strcmp(name,".img"))
	{
	    while(pinode && pinode ->i_ino != 2 && pinode->i_ino != 1)
		{
			if(dent == NULL)
				break;
			name = (char*)(dent->d_name.name);
			if(!name)
				break;
			pbuf = pbuf - strlen(name) - 1;
			*pbuf = '/';
			memcpy(pbuf+1,name,strlen(name));
			length += strlen(name) + 1;
			if((parent = dent->d_parent))
			{
				dent = parent;
				pinode = dent->d_inode;
			}
		}
		printk(KERN_INFO "the fullname is :%s \n",pbuf);
	}
	return pbuf;
}