/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * Filesystem access notification for Linux
   *
   *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
   */
  
  #ifndef __LINUX_FSNOTIFY_BACKEND_H
  #define __LINUX_FSNOTIFY_BACKEND_H
  
  #ifdef __KERNEL__

  #include <linux/idr.h> /* inotify uses this */

  #include <linux/fs.h> /* struct inode */
  #include <linux/list.h>
  #include <linux/path.h> /* struct path */
  #include <linux/spinlock.h>
  #include <linux/types.h>

  #include <linux/atomic.h>

  #include <linux/user_namespace.h>

  #include <linux/refcount.h>

  
  /*
   * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
   * convert between them.  dnotify only needs conversion at watch creation
   * so no perf loss there.  fanotify isn't defined yet, so it can use the
   * wholes if it needs more events.
   */
  #define FS_ACCESS		0x00000001	/* File was accessed */
  #define FS_MODIFY		0x00000002	/* File was modified */
  #define FS_ATTRIB		0x00000004	/* Metadata changed */
  #define FS_CLOSE_WRITE		0x00000008	/* Writtable file was closed */
  #define FS_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
  #define FS_OPEN			0x00000020	/* File was opened */
  #define FS_MOVED_FROM		0x00000040	/* File was moved from X */
  #define FS_MOVED_TO		0x00000080	/* File was moved to Y */
  #define FS_CREATE		0x00000100	/* Subfile was created */
  #define FS_DELETE		0x00000200	/* Subfile was deleted */
  #define FS_DELETE_SELF		0x00000400	/* Self was deleted */
  #define FS_MOVE_SELF		0x00000800	/* Self was moved */

  #define FS_OPEN_EXEC		0x00001000	/* File was opened for exec */

  
  #define FS_UNMOUNT		0x00002000	/* inode on umount fs */
  #define FS_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
  #define FS_IN_IGNORED		0x00008000	/* last inotify event here */

  #define FS_OPEN_PERM		0x00010000	/* open event in an permission hook */
  #define FS_ACCESS_PERM		0x00020000	/* access event in a permissions hook */

  #define FS_OPEN_EXEC_PERM	0x00040000	/* open/exec event in a permission hook */

  #define FS_EXCL_UNLINK		0x04000000	/* do not send events if object is unlinked */

  /*
   * Set on inode mark that cares about things that happen to its children.
   * Always set for dnotify and inotify.
   * Set on inode/sb/mount marks that care about parent/name info.
   */

  #define FS_EVENT_ON_CHILD	0x08000000

  #define FS_DN_RENAME		0x10000000	/* file renamed */
  #define FS_DN_MULTISHOT		0x20000000	/* dnotify multishot */
  #define FS_ISDIR		0x40000000	/* event occurred against dir */
  #define FS_IN_ONESHOT		0x80000000	/* only send event once */

  #define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)

  /*
   * Directory entry modification events - reported only to directory
   * where entry is modified and not to a watching parent.
   * The watching parent may get an FS_ATTRIB|FS_EVENT_ON_CHILD event
   * when a directory entry inside a child subdir changes.
   */

  #define ALL_FSNOTIFY_DIRENT_EVENTS	(FS_CREATE | FS_DELETE | FS_MOVE)

  #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \
  				  FS_OPEN_EXEC_PERM)

  /*

   * This is a list of all events that may get sent to a parent that is watching
   * with flag FS_EVENT_ON_CHILD based on fs event on a child of that directory.

   */
  #define FS_EVENTS_POSS_ON_CHILD   (ALL_FSNOTIFY_PERM_EVENTS | \
  				   FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
  				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \
  				   FS_OPEN | FS_OPEN_EXEC)

  /*
   * This is a list of all events that may get sent with the parent inode as the
   * @to_tell argument of fsnotify().
   * It may include events that can be sent to an inode/sb/mount mark, but cannot
   * be sent to a parent watching children.
   */
  #define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD)

  /* Events that can be reported to backends */

  #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
  			     FS_EVENTS_POSS_ON_CHILD | \
  			     FS_DELETE_SELF | FS_MOVE_SELF | FS_DN_RENAME | \
  			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED)

  
  /* Extra flags that may be reported with event or control handling of events */
  #define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \

  			     FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)

  #define ALL_FSNOTIFY_BITS   (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)

  struct fsnotify_group;
  struct fsnotify_event;

  struct fsnotify_mark;

  struct fsnotify_event_private_data;

  struct fsnotify_fname;

  struct fsnotify_iter_info;

  struct mem_cgroup;

  /*
   * Each group much define these ops.  The fsnotify infrastructure will call
   * these operations for each relevant group.
   *
   * handle_event - main call for a group to handle an fs event

   * @group:	group to notify
   * @mask:	event type and flags
   * @data:	object that event happened on
   * @data_type:	type of object for fanotify_data_XXX() accessors
   * @dir:	optional directory associated with event -
   *		if @file_name is not NULL, this is the directory that
   *		@file_name is relative to
   * @file_name:	optional file name associated with event
   * @cookie:	inotify rename cookie
   * @iter_info:	array of marks from this group that are interested in the event
   *

   * handle_inode_event - simple variant of handle_event() for groups that only
   *		have inode marks and don't have ignore mask
   * @mark:	mark to notify
   * @mask:	event type and flags
   * @inode:	inode that event happened on
   * @dir:	optional directory associated with event -
   *		if @file_name is not NULL, this is the directory that
   *		@file_name is relative to.
   * @file_name:	optional file name associated with event

   * @cookie:	inotify rename cookie

   *

   * free_group_priv - called when a group refcnt hits 0 to clean up the private union

   * freeing_mark - called when a mark is being destroyed for some reason.  The group

   *		MUST be holding a reference on each mark and that reference must be
   *		dropped in this function.  inotify uses this function to send
   *		userspace messages that marks have been removed.

   */
  struct fsnotify_ops {

  	int (*handle_event)(struct fsnotify_group *group, u32 mask,
  			    const void *data, int data_type, struct inode *dir,

  			    const struct qstr *file_name, u32 cookie,

  			    struct fsnotify_iter_info *iter_info);

  	int (*handle_inode_event)(struct fsnotify_mark *mark, u32 mask,
  			    struct inode *inode, struct inode *dir,

  			    const struct qstr *file_name, u32 cookie);

  	void (*free_group_priv)(struct fsnotify_group *group);

  	void (*freeing_mark)(struct fsnotify_mark *mark, struct fsnotify_group *group);

  	void (*free_event)(struct fsnotify_event *event);

  	/* called on final put+free to free memory */
  	void (*free_mark)(struct fsnotify_mark *mark);

  };
  
  /*
   * all of the information about the original object we want to now send to
   * a group.  If you want to carry more info from the accessing task to the
   * listener this structure is where you need to be adding fields.
   */
  struct fsnotify_event {
  	struct list_head list;

  	unsigned long objectid;	/* identifier for queue merges */

  };
  
  /*
   * A group is a "thing" that wants to receive notification about filesystem
   * events.  The mask holds the subset of event types this group cares about.
   * refcnt on a group is up to the implementor and at any moment if it goes 0
   * everything will be cleaned up.
   */
  struct fsnotify_group {

  	const struct fsnotify_ops *ops;	/* how this group handles things */

  	/*

  	 * How the refcnt is used is up to each group.  When the refcnt hits 0
  	 * fsnotify will clean up all of the resources associated with this group.
  	 * As an example, the dnotify group will always have a refcnt=1 and that
  	 * will never change.  Inotify, on the other hand, has a group per
  	 * inotify_init() and the refcnt will hit 0 only when that fd has been
  	 * closed.
  	 */

  	refcount_t refcnt;		/* things with interest in this group */

  	/* needed to send notification to userspace */

  	spinlock_t notification_lock;		/* protect the notification_list */

  	struct list_head notification_list;	/* list of event_holder this group needs to send to userspace */
  	wait_queue_head_t notification_waitq;	/* read() on the notification file blocks on this waitq */
  	unsigned int q_len;			/* events on the queue */
  	unsigned int max_events;		/* maximum events allowed on the list */

  	/*
  	 * Valid fsnotify group priorities.  Events are send in order from highest
  	 * priority to lowest priority.  We default to the lowest priority.
  	 */
  	#define FS_PRIO_0	0 /* normal notifiers, no permissions */
  	#define FS_PRIO_1	1 /* fanotify content based access control */
  	#define FS_PRIO_2	2 /* fanotify pre-content access */
  	unsigned int priority;

  	bool shutdown;		/* group is being shut down, don't queue more events */

  	/* stores all fastpath marks assoc with this group so they can be cleaned on unregister */

  	struct mutex mark_mutex;	/* protect marks_list */

  	atomic_t num_marks;		/* 1 for each mark and 1 for not being

  					 * past the point of no return when freeing
  					 * a group */

  	atomic_t user_waits;		/* Number of tasks waiting for user
  					 * response */

  	struct list_head marks_list;	/* all inode marks for this group */

  	struct fasync_struct *fsn_fa;    /* async notification */

  	struct fsnotify_event *overflow_event;	/* Event we queue when the

  						 * notification list is too
  						 * full */

  
  	struct mem_cgroup *memcg;	/* memcg to charge allocations */

  	/* groups can define private fields here or use the void *private */
  	union {
  		void *private;

  #ifdef CONFIG_INOTIFY_USER
  		struct inotify_group_private_data {
  			spinlock_t	idr_lock;
  			struct idr      idr;

  			struct ucounts *ucounts;

  		} inotify_data;
  #endif

  #ifdef CONFIG_FANOTIFY

  		struct fanotify_group_private_data {
  			/* allows a group to block waiting for a userspace response */

  			struct list_head access_list;
  			wait_queue_head_t access_waitq;

  			int flags;           /* flags from fanotify_init() */
  			int f_flags; /* event_f_flags from fanotify_init() */

  			unsigned int max_marks;

  			struct user_struct *user;

  		} fanotify_data;

  #endif /* CONFIG_FANOTIFY */

  	};
  };

  /* When calling fsnotify tell it if the data is a path or inode */
  enum fsnotify_data_type {
  	FSNOTIFY_EVENT_NONE,
  	FSNOTIFY_EVENT_PATH,
  	FSNOTIFY_EVENT_INODE,
  };

  static inline struct inode *fsnotify_data_inode(const void *data, int data_type)

  {
  	switch (data_type) {
  	case FSNOTIFY_EVENT_INODE:

  		return (struct inode *)data;

  	case FSNOTIFY_EVENT_PATH:
  		return d_inode(((const struct path *)data)->dentry);
  	default:
  		return NULL;
  	}
  }
  
  static inline const struct path *fsnotify_data_path(const void *data,
  						    int data_type)
  {
  	switch (data_type) {
  	case FSNOTIFY_EVENT_PATH:
  		return data;
  	default:
  		return NULL;
  	}
  }

  enum fsnotify_obj_type {
  	FSNOTIFY_OBJ_TYPE_INODE,

  	FSNOTIFY_OBJ_TYPE_PARENT,

  	FSNOTIFY_OBJ_TYPE_VFSMOUNT,

  	FSNOTIFY_OBJ_TYPE_SB,

  	FSNOTIFY_OBJ_TYPE_COUNT,
  	FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT
  };
  
  #define FSNOTIFY_OBJ_TYPE_INODE_FL	(1U << FSNOTIFY_OBJ_TYPE_INODE)

  #define FSNOTIFY_OBJ_TYPE_PARENT_FL	(1U << FSNOTIFY_OBJ_TYPE_PARENT)

  #define FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL	(1U << FSNOTIFY_OBJ_TYPE_VFSMOUNT)

  #define FSNOTIFY_OBJ_TYPE_SB_FL		(1U << FSNOTIFY_OBJ_TYPE_SB)

  #define FSNOTIFY_OBJ_ALL_TYPES_MASK	((1U << FSNOTIFY_OBJ_TYPE_COUNT) - 1)

  static inline bool fsnotify_valid_obj_type(unsigned int type)
  {
  	return (type < FSNOTIFY_OBJ_TYPE_COUNT);
  }

  struct fsnotify_iter_info {

  	struct fsnotify_mark *marks[FSNOTIFY_OBJ_TYPE_COUNT];

  	unsigned int report_mask;
  	int srcu_idx;
  };

  static inline bool fsnotify_iter_should_report_type(
  		struct fsnotify_iter_info *iter_info, int type)
  {
  	return (iter_info->report_mask & (1U << type));
  }
  
  static inline void fsnotify_iter_set_report_type(
  		struct fsnotify_iter_info *iter_info, int type)
  {
  	iter_info->report_mask |= (1U << type);
  }
  
  static inline void fsnotify_iter_set_report_type_mark(
  		struct fsnotify_iter_info *iter_info, int type,
  		struct fsnotify_mark *mark)
  {
  	iter_info->marks[type] = mark;
  	iter_info->report_mask |= (1U << type);
  }

  #define FSNOTIFY_ITER_FUNCS(name, NAME) \
  static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \
  		struct fsnotify_iter_info *iter_info) \
  { \
  	return (iter_info->report_mask & FSNOTIFY_OBJ_TYPE_##NAME##_FL) ? \

  		iter_info->marks[FSNOTIFY_OBJ_TYPE_##NAME] : NULL; \

  }
  
  FSNOTIFY_ITER_FUNCS(inode, INODE)

  FSNOTIFY_ITER_FUNCS(parent, PARENT)

  FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)

  FSNOTIFY_ITER_FUNCS(sb, SB)

  #define fsnotify_foreach_obj_type(type) \
  	for (type = 0; type < FSNOTIFY_OBJ_TYPE_COUNT; type++)

  /*

   * fsnotify_connp_t is what we embed in objects which connector can be attached
   * to. fsnotify_connp_t * is how we refer from connector back to object.
   */
  struct fsnotify_mark_connector;
  typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
  
  /*

   * Inode/vfsmount/sb point to this structure which tracks all marks attached to
   * the inode/vfsmount/sb. The reference to inode/vfsmount/sb is held by this

   * structure. We destroy this structure when there are no more marks attached
   * to it. The structure is protected by fsnotify_mark_srcu.

   */
  struct fsnotify_mark_connector {

  	spinlock_t lock;

  	unsigned short type;	/* Type of object [lock] */
  #define FSNOTIFY_CONN_FLAG_HAS_FSID	0x01
  	unsigned short flags;	/* flags [lock] */

  	__kernel_fsid_t fsid;	/* fsid of filesystem containing object */

  	union {
  		/* Object pointer [lock] */
  		fsnotify_connp_t *obj;

  		/* Used listing heads to free after srcu period expires */
  		struct fsnotify_mark_connector *destroy_next;
  	};

  	struct hlist_head list;

  };
  
  /*

   * A mark is simply an object attached to an in core inode which allows an

   * fsnotify listener to indicate they are either no longer interested in events
   * of a type matching mask or only interested in those events.
   *

   * These are flushed when an inode is evicted from core and may be flushed
   * when the inode is modified (as seen by fsnotify_access).  Some fsnotify
   * users (such as dnotify) will flush these when the open fd is closed and not
   * at inode eviction or modification.
   *
   * Text in brackets is showing the lock(s) protecting modifications of a
   * particular entry. obj_lock means either inode->i_lock or
   * mnt->mnt_root->d_lock depending on the mark type.

   */

  struct fsnotify_mark {

  	/* Mask this mark is for [mark->lock, group->mark_mutex] */
  	__u32 mask;
  	/* We hold one for presence in g_list. Also one ref for each 'thing'

  	 * in kernel that found and may be using this mark. */

  	refcount_t refcnt;

  	/* Group this mark is for. Set on mark creation, stable until last ref
  	 * is dropped */
  	struct fsnotify_group *group;

  	/* List of marks by group->marks_list. Also reused for queueing

  	 * mark into destroy_list when it's waiting for the end of SRCU period
  	 * before it can be freed. [group->mark_mutex] */

  	struct list_head g_list;

  	/* Protects inode / mnt pointers, flags, masks */
  	spinlock_t lock;

  	/* List of marks for inode / vfsmount [connector->lock, mark ref] */

  	struct hlist_node obj_list;

  	/* Head of list of marks for an object [mark ref] */

  	struct fsnotify_mark_connector *connector;

  	/* Events types to ignore [mark->lock, group->mark_mutex] */
  	__u32 ignored_mask;

  #define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x01
  #define FSNOTIFY_MARK_FLAG_ALIVE		0x02
  #define FSNOTIFY_MARK_FLAG_ATTACHED		0x04

  	unsigned int flags;		/* flags [mark->lock] */

  };

  #ifdef CONFIG_FSNOTIFY
  
  /* called from the vfs helpers */
  
  /* main fsnotify call to send events */

  extern int fsnotify(__u32 mask, const void *data, int data_type,
  		    struct inode *dir, const struct qstr *name,
  		    struct inode *inode, u32 cookie);

  extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,

  			   int data_type);

  extern void __fsnotify_inode_delete(struct inode *inode);

  extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);

  extern void fsnotify_sb_delete(struct super_block *sb);

  extern u32 fsnotify_get_cookie(void);

  static inline __u32 fsnotify_parent_needed_mask(__u32 mask)
  {
  	/* FS_EVENT_ON_CHILD is set on marks that want parent/name info */
  	if (!(mask & FS_EVENT_ON_CHILD))
  		return 0;
  	/*
  	 * This object might be watched by a mark that cares about parent/name
  	 * info, does it care about the specific set of events that can be
  	 * reported with parent/name info?
  	 */
  	return mask & FS_EVENTS_POSS_TO_PARENT;
  }

  static inline int fsnotify_inode_watches_children(struct inode *inode)
  {
  	/* FS_EVENT_ON_CHILD is set if the inode may care */
  	if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
  		return 0;
  	/* this inode might care about child events, does it care about the
  	 * specific set of events that can happen on a child? */
  	return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
  }
  
  /*
   * Update the dentry with a flag indicating the interest of its parent to receive
   * filesystem events when those events happens to this dentry->d_inode.
   */

  static inline void fsnotify_update_flags(struct dentry *dentry)

  {

  	assert_spin_locked(&dentry->d_lock);

  	/*
  	 * Serialisation of setting PARENT_WATCHED on the dentries is provided
  	 * by d_lock. If inotify_inode_watched changes after we have taken
  	 * d_lock, the following __fsnotify_update_child_dentry_flags call will
  	 * find our entry, so it will spin until we complete here, and update
  	 * us with the new state.
  	 */

  	if (fsnotify_inode_watches_children(dentry->d_parent->d_inode))

  		dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
  	else
  		dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
  }

  /* called from fsnotify listeners, such as fanotify or dnotify */

  /* create a new group */

  extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops);

  /* get reference to a group */
  extern void fsnotify_get_group(struct fsnotify_group *group);

  /* drop reference on a group from fsnotify_alloc_group */

  extern void fsnotify_put_group(struct fsnotify_group *group);

  /* group destruction begins, stop queuing new events */
  extern void fsnotify_group_stop_queueing(struct fsnotify_group *group);

  /* destroy group */
  extern void fsnotify_destroy_group(struct fsnotify_group *group);

  /* fasync handler function */
  extern int fsnotify_fasync(int fd, struct file *file, int on);

  /* Free event from memory */
  extern void fsnotify_destroy_event(struct fsnotify_group *group,
  				   struct fsnotify_event *event);

  /* attach the event to the group notification queue */

  extern int fsnotify_add_event(struct fsnotify_group *group,
  			      struct fsnotify_event *event,
  			      int (*merge)(struct list_head *,
  					   struct fsnotify_event *));

  /* Queue overflow event to a notification group */
  static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
  {
  	fsnotify_add_event(group, group->overflow_event, NULL);
  }

  /* true if the group notification queue is empty */
  extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
  /* return, but do not dequeue the first event on the notification queue */

  extern struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group);

  /* return AND dequeue the first event on the notification queue */

  extern struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group);

  /* Remove event queued in the notification list */
  extern void fsnotify_remove_queued_event(struct fsnotify_group *group,
  					 struct fsnotify_event *event);

  /* functions used to manipulate the marks attached to inodes */

  /* Get mask of events for a list of marks */
  extern __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn);

  /* Calculate mask of events for a list of marks */
  extern void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);

  extern void fsnotify_init_mark(struct fsnotify_mark *mark,

  			       struct fsnotify_group *group);

  /* Find mark belonging to given group in the list of marks */

  extern struct fsnotify_mark *fsnotify_find_mark(fsnotify_connp_t *connp,
  						struct fsnotify_group *group);

  /* Get cached fsid of filesystem containing object */
  extern int fsnotify_get_conn_fsid(const struct fsnotify_mark_connector *conn,
  				  __kernel_fsid_t *fsid);

  /* attach the mark to the object */
  extern int fsnotify_add_mark(struct fsnotify_mark *mark,
  			     fsnotify_connp_t *connp, unsigned int type,

  			     int allow_dups, __kernel_fsid_t *fsid);

  extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,

  				    fsnotify_connp_t *connp,
  				    unsigned int type, int allow_dups,
  				    __kernel_fsid_t *fsid);

  /* attach the mark to the inode */
  static inline int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
  					  struct inode *inode,
  					  int allow_dups)
  {

  	return fsnotify_add_mark(mark, &inode->i_fsnotify_marks,

  				 FSNOTIFY_OBJ_TYPE_INODE, allow_dups, NULL);

  }
  static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark,
  						 struct inode *inode,
  						 int allow_dups)
  {

  	return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks,

  					FSNOTIFY_OBJ_TYPE_INODE, allow_dups,
  					NULL);

  }

  /* given a group and a mark, flag mark to be freed when all references are dropped */
  extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
  				  struct fsnotify_group *group);

  /* detach mark from inode / mount list, group list, drop inode reference */
  extern void fsnotify_detach_mark(struct fsnotify_mark *mark);
  /* free mark */
  extern void fsnotify_free_mark(struct fsnotify_mark *mark);

  /* Wait until all marks queued for destruction are destroyed */
  extern void fsnotify_wait_marks_destroyed(void);

  /* run all the marks in a group, and clear all of the marks attached to given object type */

  extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group, unsigned int type);

  /* run all the marks in a group, and clear all of the vfsmount marks */
  static inline void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
  {

  	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL);

  }
  /* run all the marks in a group, and clear all of the inode marks */
  static inline void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
  {

  	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_INODE_FL);

  }

  /* run all the marks in a group, and clear all of the sn marks */
  static inline void fsnotify_clear_sb_marks_by_group(struct fsnotify_group *group)
  {
  	fsnotify_clear_marks_by_group(group, FSNOTIFY_OBJ_TYPE_SB_FL);
  }

  extern void fsnotify_get_mark(struct fsnotify_mark *mark);
  extern void fsnotify_put_mark(struct fsnotify_mark *mark);

  extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
  extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);

  static inline void fsnotify_init_event(struct fsnotify_event *event,

  				       unsigned long objectid)

  {
  	INIT_LIST_HEAD(&event->list);

  	event->objectid = objectid;

  }

  #else

  static inline int fsnotify(__u32 mask, const void *data, int data_type,
  			   struct inode *dir, const struct qstr *name,
  			   struct inode *inode, u32 cookie)

  {
  	return 0;
  }

  static inline int __fsnotify_parent(struct dentry *dentry, __u32 mask,

  				  const void *data, int data_type)

  {
  	return 0;
  }

  static inline void __fsnotify_inode_delete(struct inode *inode)
  {}

  static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
  {}

  static inline void fsnotify_sb_delete(struct super_block *sb)
  {}

  static inline void fsnotify_update_flags(struct dentry *dentry)

  {}

  static inline u32 fsnotify_get_cookie(void)
  {
  	return 0;
  }

  static inline void fsnotify_unmount_inodes(struct super_block *sb)

  {}

  #endif	/* CONFIG_FSNOTIFY */
  
  #endif	/* __KERNEL __ */
  
  #endif	/* __LINUX_FSNOTIFY_BACKEND_H */