text: #ifndef _LINUX_FS_NOTIFY_H
  #define _LINUX_FS_NOTIFY_H
  
  /*
   * include/linux/fsnotify.h - generic hooks for filesystem notification, to
   * reduce in-source duplication from both dnotify and inotify.
   *
   * We don't compile any of this away in some complicated menagerie of ifdefs.
   * Instead, we rely on the code inside to optimize away as needed.
   *
   * (C) Copyright 2005 Robert Love
   */
  
  #include <linux/fsnotify_backend.h>
  #include <linux/audit.h>
  #include <linux/slab.h>
  #include <linux/bug.h>
  
  /* Notify this dentry's parent about a child's events. */
  static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
  {
  	if (!dentry)
  		dentry = path->dentry;
  
  	return __fsnotify_parent(path, dentry, mask);
  }
  
  /* simple call site for access decisions */
  static inline int fsnotify_perm(struct file *file, int mask)
  {
  	struct path *path = &file->f_path;
  	/*
  	 * Do not use file_inode() here or anywhere in this file to get the
  	 * inode.  That would break *notity on overlayfs.
  	 */
  	struct inode *inode = path->dentry->d_inode;
  	__u32 fsnotify_mask = 0;
  	int ret;
  
  	if (file->f_mode & FMODE_NONOTIFY)
  		return 0;
  	if (!(mask & (MAY_READ | MAY_OPEN)))
  		return 0;
  	if (mask & MAY_OPEN)
  		fsnotify_mask = FS_OPEN_PERM;
  	else if (mask & MAY_READ)
  		fsnotify_mask = FS_ACCESS_PERM;
  	else
  		BUG();
  
  	ret = fsnotify_parent(path, NULL, fsnotify_mask);
  	if (ret)
  		return ret;
  
  	return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  }
  
  /*
   * fsnotify_link_count - inode's link count changed
   */
  static inline void fsnotify_link_count(struct inode *inode)
  {
  	fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  }
  
  /*
   * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
   */
  static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
  				 const unsigned char *old_name,
  				 int isdir, struct inode *target, struct dentry *moved)
  {
  	struct inode *source = moved->d_inode;
  	u32 fs_cookie = fsnotify_get_cookie();
  	__u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
  	__u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
  	const unsigned char *new_name = moved->d_name.name;
  
  	if (old_dir == new_dir)
  		old_dir_mask |= FS_DN_RENAME;
  
  	if (isdir) {
  		old_dir_mask |= FS_ISDIR;
  		new_dir_mask |= FS_ISDIR;
  	}
  
  	fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
  		 fs_cookie);
  	fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
  		 fs_cookie);
  
  	if (target)
  		fsnotify_link_count(target);
  
  	if (source)
  		fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  	audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
  }
  
  /*
   * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
   */
  static inline void fsnotify_inode_delete(struct inode *inode)
  {
  	__fsnotify_inode_delete(inode);
  }
  
  /*
   * fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
   */
  static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
  {
  	__fsnotify_vfsmount_delete(mnt);
  }
  
  /*
   * fsnotify_nameremove - a filename was removed from a directory
   */
  static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
  {
  	__u32 mask = FS_DELETE;
  
  	if (isdir)
  		mask |= FS_ISDIR;
  
  	fsnotify_parent(NULL, dentry, mask);
  }
  
  /*
   * fsnotify_inoderemove - an inode is going away
   */
  static inline void fsnotify_inoderemove(struct inode *inode)
  {
  	fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  	__fsnotify_inode_delete(inode);
  }
  
  /*
   * fsnotify_create - 'name' was linked in
   */
  static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
  {
  	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
  
  	fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
  }
  
  /*
   * fsnotify_link - new hardlink in 'inode' directory
   * Note: We have to pass also the linked inode ptr as some filesystems leave
   *   new_dentry->d_inode NULL and instantiate inode pointer later
   */
  static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
  {
  	fsnotify_link_count(inode);
  	audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
  
  	fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
  }
  
  /*
   * fsnotify_mkdir - directory 'name' was created
   */
  static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
  {
  	__u32 mask = (FS_CREATE | FS_ISDIR);
  	struct inode *d_inode = dentry->d_inode;
  
  	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
  
  	fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
  }
  
  /*
   * fsnotify_access - file was read
   */
  static inline void fsnotify_access(struct file *file)
  {
  	struct path *path = &file->f_path;
  	struct inode *inode = path->dentry->d_inode;
  	__u32 mask = FS_ACCESS;
  
  	if (S_ISDIR(inode->i_mode))
  		mask |= FS_ISDIR;
  
  	if (!(file->f_mode & FMODE_NONOTIFY)) {
  		fsnotify_parent(path, NULL, mask);
  		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  	}
  }
  
  /*
   * fsnotify_modify - file was modified
   */
  static inline void fsnotify_modify(struct file *file)
  {
  	struct path *path = &file->f_path;
  	struct inode *inode = path->dentry->d_inode;
  	__u32 mask = FS_MODIFY;
  
  	if (S_ISDIR(inode->i_mode))
  		mask |= FS_ISDIR;
  
  	if (!(file->f_mode & FMODE_NONOTIFY)) {
  		fsnotify_parent(path, NULL, mask);
  		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  	}
  }
  
  /*
   * fsnotify_open - file was opened
   */
  static inline void fsnotify_open(struct file *file)
  {
  	struct path *path = &file->f_path;
  	struct path lower_path;
  	struct inode *inode = path->dentry->d_inode;
  
  	__u32 mask = FS_OPEN;
  
  	if (S_ISDIR(inode->i_mode))
  		mask |= FS_ISDIR;
  
  	if (path->dentry->d_op && path->dentry->d_op->d_canonical_path) {
  		path->dentry->d_op->d_canonical_path(path, &lower_path);
  		fsnotify_parent(&lower_path, NULL, mask);
  		fsnotify(lower_path.dentry->d_inode, mask, &lower_path,
  						FSNOTIFY_EVENT_PATH, NULL, 0);
  		path_put(&lower_path);
  	}
  	fsnotify_parent(path, NULL, mask);
  	fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  }
  
  /*
   * fsnotify_close - file was closed
   */
  static inline void fsnotify_close(struct file *file)
  {
  	struct path *path = &file->f_path;
  	struct inode *inode = path->dentry->d_inode;
  	fmode_t mode = file->f_mode;
  	__u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
  
  	if (S_ISDIR(inode->i_mode))
  		mask |= FS_ISDIR;
  
  	if (!(file->f_mode & FMODE_NONOTIFY)) {
  		fsnotify_parent(path, NULL, mask);
  		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
  	}
  }
  
  /*
   * fsnotify_xattr - extended attributes were changed
   */
  static inline void fsnotify_xattr(struct dentry *dentry)
  {
  	struct inode *inode = dentry->d_inode;
  	__u32 mask = FS_ATTRIB;
  
  	if (S_ISDIR(inode->i_mode))
  		mask |= FS_ISDIR;
  
  	fsnotify_parent(NULL, dentry, mask);
  	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  }
  
  /*
   * fsnotify_change - notify_change event.  file was modified and/or metadata
   * was changed.
   */
  static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
  {
  	struct inode *inode = dentry->d_inode;
  	__u32 mask = 0;
  
  	if (ia_valid & ATTR_UID)
  		mask |= FS_ATTRIB;
  	if (ia_valid & ATTR_GID)
  		mask |= FS_ATTRIB;
  	if (ia_valid & ATTR_SIZE)
  		mask |= FS_MODIFY;
  
  	/* both times implies a utime(s) call */
  	if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
  		mask |= FS_ATTRIB;
  	else if (ia_valid & ATTR_ATIME)
  		mask |= FS_ACCESS;
  	else if (ia_valid & ATTR_MTIME)
  		mask |= FS_MODIFY;
  
  	if (ia_valid & ATTR_MODE)
  		mask |= FS_ATTRIB;
  
  	if (mask) {
  		if (S_ISDIR(inode->i_mode))
  			mask |= FS_ISDIR;
  
  		fsnotify_parent(NULL, dentry, mask);
  		fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
  	}
  }
  
  #endif	/* _LINUX_FS_NOTIFY_H */
  