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kernel/linux-imx6_3.14.28/include/linux/namei.h 3.36 KB
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  #ifndef _LINUX_NAMEI_H
  #define _LINUX_NAMEI_H
  
  #include <linux/dcache.h>
  #include <linux/errno.h>
  #include <linux/linkage.h>
  #include <linux/path.h>
  
  struct vfsmount;
  
  enum { MAX_NESTED_LINKS = 8 };
  
  struct nameidata {
  	struct path	path;
  	struct qstr	last;
  	struct path	root;
  	struct inode	*inode; /* path.dentry.d_inode */
  	unsigned int	flags;
  	unsigned	seq, m_seq;
  	int		last_type;
  	unsigned	depth;
  	char *saved_names[MAX_NESTED_LINKS + 1];
  };
  
  /*
   * Type of the last component on LOOKUP_PARENT
   */
  enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
  
  /*
   * The bitmask for a lookup event:
   *  - follow links at the end
   *  - require a directory
   *  - ending slashes ok even for nonexistent files
   *  - internal "there are more path components" flag
   *  - dentry cache is untrusted; force a real lookup
   *  - suppress terminal automount
   */
  #define LOOKUP_FOLLOW		0x0001
  #define LOOKUP_DIRECTORY	0x0002
  #define LOOKUP_AUTOMOUNT	0x0004
  
  #define LOOKUP_PARENT		0x0010
  #define LOOKUP_REVAL		0x0020
  #define LOOKUP_RCU		0x0040
  
  /*
   * Intent data
   */
  #define LOOKUP_OPEN		0x0100
  #define LOOKUP_CREATE		0x0200
  #define LOOKUP_EXCL		0x0400
  #define LOOKUP_RENAME_TARGET	0x0800
  
  #define LOOKUP_JUMPED		0x1000
  #define LOOKUP_ROOT		0x2000
  #define LOOKUP_EMPTY		0x4000
  
  extern int user_path_at(int, const char __user *, unsigned, struct path *);
  extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
  
  #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
  #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
  #define user_path_dir(name, path) \
  	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
  
  extern int kern_path(const char *, unsigned, struct path *);
  
  extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
  extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
  extern void done_path_create(struct path *, struct dentry *);
  extern struct dentry *kern_path_locked(const char *, struct path *);
  extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
  
  extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
  
  extern int follow_down_one(struct path *);
  extern int follow_down(struct path *);
  extern int follow_up(struct path *);
  
  extern struct dentry *lock_rename(struct dentry *, struct dentry *);
  extern void unlock_rename(struct dentry *, struct dentry *);
  
  extern void nd_jump_link(struct nameidata *nd, struct path *path);
  
  static inline void nd_set_link(struct nameidata *nd, char *path)
  {
  	nd->saved_names[nd->depth] = path;
  }
  
  static inline char *nd_get_link(struct nameidata *nd)
  {
  	return nd->saved_names[nd->depth];
  }
  
  static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
  {
  	((char *) name)[min(len, maxlen)] = '\0';
  }
  
  /**
   * retry_estale - determine whether the caller should retry an operation
   * @error: the error that would currently be returned
   * @flags: flags being used for next lookup attempt
   *
   * Check to see if the error code was -ESTALE, and then determine whether
   * to retry the call based on whether "flags" already has LOOKUP_REVAL set.
   *
   * Returns true if the caller should try the operation again.
   */
  static inline bool
  retry_estale(const long error, const unsigned int flags)
  {
  	return error == -ESTALE && !(flags & LOOKUP_REVAL);
  }
  
  #endif /* _LINUX_NAMEI_H */