[linux-2.6-block.git] / include / linux / fsnotify_backend.h

/*
 * 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>

/*
 * 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_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_EXCL_UNLINK		0x04000000	/* do not send events if object is unlinked */
#define FS_ISDIR		0x40000000	/* event occurred against dir */
#define FS_IN_ONESHOT		0x80000000	/* only send event once */

#define FS_DN_RENAME		0x10000000	/* file renamed */
#define FS_DN_MULTISHOT		0x20000000	/* dnotify multishot */

/* This inode cares about things that happen to its children.  Always set for
 * dnotify and inotify. */
#define FS_EVENT_ON_CHILD	0x08000000

/* This is a list of all events that may get sent to a parernt based on fs event
 * happening to inodes inside that directory */
#define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)

#define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)

#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)

#define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
			     FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
			     FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
			     FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)

struct fsnotify_group;
struct fsnotify_event;
struct fsnotify_mark;
struct fsnotify_event_private_data;
struct fsnotify_fname;

/*
 * Each group much define these ops.  The fsnotify infrastructure will call
 * these operations for each relevant group.
 *
 * should_send_event - given a group, inode, and mask this function determines
 *		if the group is interested in this event.
 * handle_event - main call for a group to handle an fs event
 * 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,
			    struct inode *inode,
			    struct fsnotify_mark *inode_mark,
			    struct fsnotify_mark *vfsmount_mark,
			    u32 mask, void *data, int data_type,
			    const unsigned char *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);
};

/*
 * 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;
	/* inode may ONLY be dereferenced during handle_event(). */
	struct inode *inode;	/* either the inode the event happened to or its parent */
	u32 mask;		/* the type of access, bitwise OR for FS_* event types */
};

/*
 * 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 {
	/*
	 * 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.
	 */
	atomic_t refcnt;		/* things with interest in this group */

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

	/* needed to send notification to userspace */
	struct mutex notification_mutex;	/* 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;

	/* 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 */
	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 */

	/* 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 user_struct      *user;
		} inotify_data;
#endif
#ifdef CONFIG_FANOTIFY
		struct fanotify_group_private_data {
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
			/* allows a group to block waiting for a userspace response */
			spinlock_t access_lock;
			struct list_head access_list;
			wait_queue_head_t access_waitq;
			atomic_t bypass_perm;
#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
			int f_flags;
			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 */
#define FSNOTIFY_EVENT_NONE	0
#define FSNOTIFY_EVENT_PATH	1
#define FSNOTIFY_EVENT_INODE	2

/*
 * 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.
 */
struct fsnotify_mark {
	__u32 mask;			/* mask this mark is for */
	/* we hold ref for each i_list and g_list.  also one ref for each 'thing'
	 * in kernel that found and may be using this mark. */
	atomic_t refcnt;		/* active things looking at this mark */
	struct fsnotify_group *group;	/* group this mark is for */
	struct list_head g_list;	/* list of marks by group->i_fsnotify_marks
					 * Also reused for queueing mark into
					 * destroy_list when it's waiting for
					 * the end of SRCU period before it can
					 * be freed */
	spinlock_t lock;		/* protect group and inode */
	struct hlist_node obj_list;	/* list of marks for inode / vfsmount */
	struct list_head free_list;	/* tmp list used when freeing this mark */
	union {
		struct inode *inode;	/* inode this mark is associated with */
		struct vfsmount *mnt;	/* vfsmount this mark is associated with */
	};
	__u32 ignored_mask;		/* events types to ignore */
#define FSNOTIFY_MARK_FLAG_INODE		0x01
#define FSNOTIFY_MARK_FLAG_VFSMOUNT		0x02
#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED	0x04
#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x08
#define FSNOTIFY_MARK_FLAG_ALIVE		0x10
	unsigned int flags;		/* vfsmount or inode mark? */
	void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
};

#ifdef CONFIG_FSNOTIFY

/* called from the vfs helpers */

/* main fsnotify call to send events */
extern int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
		    const unsigned char *name, u32 cookie);
extern int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
extern void __fsnotify_inode_delete(struct inode *inode);
extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern u32 fsnotify_get_cookie(void);

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_dcache_flags(struct dentry *dentry)
{
	struct dentry *parent;

	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.
	 */
	parent = dentry->d_parent;
	if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
		dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
	else
		dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
}

/*
 * fsnotify_d_instantiate - instantiate a dentry for inode
 */
static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
{
	if (!inode)
		return;

	spin_lock(&dentry->d_lock);
	__fsnotify_update_dcache_flags(dentry);
	spin_unlock(&dentry->d_lock);
}

/* 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);
/* 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 *));
/* Remove passed event from groups notification queue */
extern void fsnotify_remove_event(struct fsnotify_group *group, struct fsnotify_event *event);
/* 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);

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

/* run all marks associated with a vfsmount and update mnt->mnt_fsnotify_mask */
extern void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt);
/* run all marks associated with an inode and update inode->i_fsnotify_mask */
extern void fsnotify_recalc_inode_mask(struct inode *inode);
extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(struct fsnotify_mark *mark));
/* find (and take a reference) to a mark associated with group and inode */
extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode);
/* find (and take a reference) to a mark associated with group and vfsmount */
extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt);
/* copy the values from old into new */
extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old);
/* set the ignored_mask of a mark */
extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask);
/* set the mask of a mark (might pin the object into memory */
extern void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask);
/* attach the mark to both the group and the inode */
extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group,
			     struct inode *inode, struct vfsmount *mnt, int allow_dups);
extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct fsnotify_group *group,
				    struct inode *inode, struct vfsmount *mnt, int allow_dups);
/* 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);
extern void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark,
					 struct fsnotify_group *group);
/* run all the marks in a group, and clear all of the vfsmount marks */
extern void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group);
/* run all the marks in a group, and clear all of the inode marks */
extern void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group);
/* run all the marks in a group, and clear all of the marks where mark->flags & flags is true*/
extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags);
/* run all the marks in a group, and flag them to be freed */
extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group);
extern void fsnotify_get_mark(struct fsnotify_mark *mark);
extern void fsnotify_put_mark(struct fsnotify_mark *mark);
extern void fsnotify_unmount_inodes(struct list_head *list);

/* put here because inotify does some weird stuff when destroying watches */
extern void fsnotify_init_event(struct fsnotify_event *event,
				struct inode *to_tell, u32 mask);

#else

static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
			   const unsigned char *name, u32 cookie)
{
	return 0;
}

static inline int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
{
	return 0;
}

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

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

static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
{}

static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
{}

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

static inline void fsnotify_unmount_inodes(struct list_head *list)
{}

#endif	/* CONFIG_FSNOTIFY */

#endif	/* __KERNEL __ */

#endif	/* __LINUX_FSNOTIFY_BACKEND_H */
Commit	Line	Data
90586523 EP	1	/*
	2	* Filesystem access notification for Linux
	3	*
	4	* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
	5	*/
	6
	7	#ifndef __LINUX_FSNOTIFY_BACKEND_H
	8	#define __LINUX_FSNOTIFY_BACKEND_H
	9
	10	#ifdef __KERNEL__
	11
63c882a0	12	#include <linux/idr.h> /* inotify uses this */
90586523 EP	13	#include <linux/fs.h> /* struct inode */
	14	#include <linux/list.h>
	15	#include <linux/path.h> /* struct path */
	16	#include <linux/spinlock.h>
	17	#include <linux/types.h>
60063497	18	#include <linux/atomic.h>
90586523 EP	19
	20	/*
	21	* IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
	22	* convert between them. dnotify only needs conversion at watch creation
	23	* so no perf loss there. fanotify isn't defined yet, so it can use the
	24	* wholes if it needs more events.
	25	*/
	26	#define FS_ACCESS 0x00000001 /* File was accessed */
	27	#define FS_MODIFY 0x00000002 /* File was modified */
	28	#define FS_ATTRIB 0x00000004 /* Metadata changed */
	29	#define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
	30	#define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
	31	#define FS_OPEN 0x00000020 /* File was opened */
	32	#define FS_MOVED_FROM 0x00000040 /* File was moved from X */
	33	#define FS_MOVED_TO 0x00000080 /* File was moved to Y */
	34	#define FS_CREATE 0x00000100 /* Subfile was created */
	35	#define FS_DELETE 0x00000200 /* Subfile was deleted */
	36	#define FS_DELETE_SELF 0x00000400 /* Self was deleted */
	37	#define FS_MOVE_SELF 0x00000800 /* Self was moved */
	38
	39	#define FS_UNMOUNT 0x00002000 /* inode on umount fs */
	40	#define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
	41	#define FS_IN_IGNORED 0x00008000 /* last inotify event here */
	42
c4ec54b4 EP	43	#define FS_OPEN_PERM 0x00010000 /* open event in an permission hook */
	44	#define FS_ACCESS_PERM 0x00020000 /* access event in a permissions hook */
	45
8c1934c8	46	#define FS_EXCL_UNLINK 0x04000000 /* do not send events if object is unlinked */
b29866aa	47	#define FS_ISDIR 0x40000000 /* event occurred against dir */
90586523 EP	48	#define FS_IN_ONESHOT 0x80000000 /* only send event once */
	49
	50	#define FS_DN_RENAME 0x10000000 /* file renamed */
	51	#define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */
	52
c28f7e56 EP	53	/* This inode cares about things that happen to its children. Always set for
	54	* dnotify and inotify. */
	55	#define FS_EVENT_ON_CHILD 0x08000000
	56
	57	/* This is a list of all events that may get sent to a parernt based on fs event
	58	* happening to inodes inside that directory */
	59	#define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS \| FS_MODIFY \| FS_ATTRIB \|\
	60	FS_CLOSE_WRITE \| FS_CLOSE_NOWRITE \| FS_OPEN \|\
	61	FS_MOVED_FROM \| FS_MOVED_TO \| FS_CREATE \|\
a4f9a9a6	62	FS_DELETE \| FS_OPEN_PERM \| FS_ACCESS_PERM)
c28f7e56	63
e9fd702a EP	64	#define FS_MOVE (FS_MOVED_FROM \| FS_MOVED_TO)
e9fd702a EP	65
ff8bcbd0 EP	66	#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM \| FS_ACCESS_PERM)
ff8bcbd0 EP	67
20dee624 EP	68	#define ALL_FSNOTIFY_EVENTS (FS_ACCESS \| FS_MODIFY \| FS_ATTRIB \| \
	69	FS_CLOSE_WRITE \| FS_CLOSE_NOWRITE \| FS_OPEN \| \
	70	FS_MOVED_FROM \| FS_MOVED_TO \| FS_CREATE \| \
	71	FS_DELETE \| FS_DELETE_SELF \| FS_MOVE_SELF \| \
	72	FS_UNMOUNT \| FS_Q_OVERFLOW \| FS_IN_IGNORED \| \
	73	FS_OPEN_PERM \| FS_ACCESS_PERM \| FS_EXCL_UNLINK \| \
b29866aa	74	FS_ISDIR \| FS_IN_ONESHOT \| FS_DN_RENAME \| \
20dee624 EP	75	FS_DN_MULTISHOT \| FS_EVENT_ON_CHILD)
20dee624 EP	76
90586523 EP	77	struct fsnotify_group;
90586523 EP	78	struct fsnotify_event;
e61ce867	79	struct fsnotify_mark;
e4aff117	80	struct fsnotify_event_private_data;
7053aee2	81	struct fsnotify_fname;
90586523 EP	82
	83	/*
	84	* Each group much define these ops. The fsnotify infrastructure will call
	85	* these operations for each relevant group.
	86	*
3be25f49 EP	87	* should_send_event - given a group, inode, and mask this function determines
3be25f49 EP	88	* if the group is interested in this event.
90586523 EP	89	* handle_event - main call for a group to handle an fs event
90586523 EP	90	* free_group_priv - called when a group refcnt hits 0 to clean up the private union
6960b0d9 LS	91	* freeing_mark - called when a mark is being destroyed for some reason. The group
	92	* MUST be holding a reference on each mark and that reference must be
	93	* dropped in this function. inotify uses this function to send
	94	* userspace messages that marks have been removed.
90586523 EP	95	*/
90586523 EP	96	struct fsnotify_ops {
ce8f76fb	97	int (handle_event)(struct fsnotify_group group,
7053aee2	98	struct inode *inode,
ce8f76fb EP	99	struct fsnotify_mark *inode_mark,
ce8f76fb EP	100	struct fsnotify_mark *vfsmount_mark,
7053aee2	101	u32 mask, void *data, int data_type,
45a22f4c	102	const unsigned char *file_name, u32 cookie);
90586523	103	void (free_group_priv)(struct fsnotify_group group);
841bdc10	104	void (freeing_mark)(struct fsnotify_mark mark, struct fsnotify_group *group);
7053aee2 JK	105	void (free_event)(struct fsnotify_event event);
	106	};
	107
	108	/*
	109	* all of the information about the original object we want to now send to
	110	* a group. If you want to carry more info from the accessing task to the
	111	* listener this structure is where you need to be adding fields.
	112	*/
	113	struct fsnotify_event {
	114	struct list_head list;
	115	/* inode may ONLY be dereferenced during handle_event(). */
	116	struct inode inode; / either the inode the event happened to or its parent */
	117	u32 mask; /* the type of access, bitwise OR for FS_* event types */
90586523 EP	118	};
	119
	120	/*
	121	* A group is a "thing" that wants to receive notification about filesystem
	122	* events. The mask holds the subset of event types this group cares about.
	123	* refcnt on a group is up to the implementor and at any moment if it goes 0
	124	* everything will be cleaned up.
	125	*/
	126	struct fsnotify_group {
90586523 EP	127	/*
	128	* How the refcnt is used is up to each group. When the refcnt hits 0
	129	* fsnotify will clean up all of the resources associated with this group.
	130	* As an example, the dnotify group will always have a refcnt=1 and that
	131	* will never change. Inotify, on the other hand, has a group per
	132	* inotify_init() and the refcnt will hit 0 only when that fd has been
	133	* closed.
	134	*/
	135	atomic_t refcnt; /* things with interest in this group */
90586523 EP	136
	137	const struct fsnotify_ops ops; / how this group handles things */
	138
a2d8bc6c EP	139	/* needed to send notification to userspace */
	140	struct mutex notification_mutex; /* protect the notification_list */
	141	struct list_head notification_list; /* list of event_holder this group needs to send to userspace */
	142	wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */
	143	unsigned int q_len; /* events on the queue */
	144	unsigned int max_events; /* maximum events allowed on the list */
6ad2d4e3 EP	145	/*
	146	* Valid fsnotify group priorities. Events are send in order from highest
	147	* priority to lowest priority. We default to the lowest priority.
	148	*/
	149	#define FS_PRIO_0 0 /* normal notifiers, no permissions */
	150	#define FS_PRIO_1 1 /* fanotify content based access control */
	151	#define FS_PRIO_2 2 /* fanotify pre-content access */
	152	unsigned int priority;
a2d8bc6c	153
e61ce867	154	/* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
986ab098	155	struct mutex mark_mutex; /* protect marks_list */
841bdc10	156	atomic_t num_marks; /* 1 for each mark and 1 for not being
3be25f49 EP	157	* past the point of no return when freeing
3be25f49 EP	158	* a group */
e61ce867	159	struct list_head marks_list; /* all inode marks for this group */
3be25f49	160
7053aee2 JK	161	struct fasync_struct fsn_fa; / async notification */
7053aee2 JK	162
ff57cd58	163	struct fsnotify_event overflow_event; / Event we queue when the
7053aee2 JK	164	* notification list is too
7053aee2 JK	165	* full */
0a6b6bd5	166
90586523 EP	167	/* groups can define private fields here or use the void private /
	168	union {
	169	void *private;
63c882a0 EP	170	#ifdef CONFIG_INOTIFY_USER
	171	struct inotify_group_private_data {
	172	spinlock_t idr_lock;
	173	struct idr idr;
63c882a0 EP	174	struct user_struct *user;
63c882a0 EP	175	} inotify_data;
9e66e423	176	#endif
80af2588	177	#ifdef CONFIG_FANOTIFY
9e66e423	178	struct fanotify_group_private_data {
80af2588	179	#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
9e66e423	180	/* allows a group to block waiting for a userspace response */
9573f793	181	spinlock_t access_lock;
9e66e423 EP	182	struct list_head access_list;
9e66e423 EP	183	wait_queue_head_t access_waitq;
09e5f14e	184	atomic_t bypass_perm;
80af2588 EP	185	#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
80af2588 EP	186	int f_flags;
e7099d8a	187	unsigned int max_marks;
4afeff85	188	struct user_struct *user;
9e66e423	189	} fanotify_data;
80af2588	190	#endif /* CONFIG_FANOTIFY */
90586523 EP	191	};
	192	};
	193
90586523 EP	194	/* when calling fsnotify tell it if the data is a path or inode */
90586523 EP	195	#define FSNOTIFY_EVENT_NONE 0
2069601b	196	#define FSNOTIFY_EVENT_PATH 1
90586523	197	#define FSNOTIFY_EVENT_INODE 2
90586523	198
3be25f49	199	/*
841bdc10	200	* a mark is simply an object attached to an in core inode which allows an
3be25f49 EP	201	* fsnotify listener to indicate they are either no longer interested in events
	202	* of a type matching mask or only interested in those events.
	203	*
	204	* these are flushed when an inode is evicted from core and may be flushed
	205	* when the inode is modified (as seen by fsnotify_access). Some fsnotify users
	206	* (such as dnotify) will flush these when the open fd is closed and not at
	207	* inode eviction or modification.
	208	*/
e61ce867	209	struct fsnotify_mark {
841bdc10	210	__u32 mask; /* mask this mark is for */
3be25f49 EP	211	/* we hold ref for each i_list and g_list. also one ref for each 'thing'
	212	* in kernel that found and may be using this mark. */
	213	atomic_t refcnt; /* active things looking at this mark */
841bdc10	214	struct fsnotify_group group; / group this mark is for */
37d469e7 JK	215	struct list_head g_list; /* list of marks by group->i_fsnotify_marks
	216	* Also reused for queueing mark into
	217	* destroy_list when it's waiting for
	218	* the end of SRCU period before it can
	219	* be freed */
2823e04d	220	spinlock_t lock; /* protect group and inode */
0809ab69 JK	221	struct hlist_node obj_list; /* list of marks for inode / vfsmount */
0809ab69 JK	222	struct list_head free_list; /* tmp list used when freeing this mark */
2823e04d	223	union {
0809ab69 JK	224	struct inode inode; / inode this mark is associated with */
0809ab69 JK	225	struct vfsmount mnt; / vfsmount this mark is associated with */
2823e04d	226	};
d8c0fca6	227	__u32 ignored_mask; /* events types to ignore */
90b1e7a5 EP	228	#define FSNOTIFY_MARK_FLAG_INODE 0x01
	229	#define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02
	230	#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04
c908370f	231	#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08
700307a2	232	#define FSNOTIFY_MARK_FLAG_ALIVE 0x10
098cf2fc	233	unsigned int flags; /* vfsmount or inode mark? */
841bdc10	234	void (free_mark)(struct fsnotify_mark mark); /* called on final put+free */
3be25f49 EP	235	};
3be25f49 EP	236
90586523 EP	237	#ifdef CONFIG_FSNOTIFY
	238
	239	/* called from the vfs helpers */
	240
	241	/* main fsnotify call to send events */
c4ec54b4 EP	242	extern int fsnotify(struct inode to_tell, __u32 mask, void data, int data_is,
c4ec54b4 EP	243	const unsigned char *name, u32 cookie);
52420392	244	extern int __fsnotify_parent(struct path path, struct dentry dentry, __u32 mask);
3be25f49	245	extern void __fsnotify_inode_delete(struct inode *inode);
ca9c726e	246	extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
47882c6f	247	extern u32 fsnotify_get_cookie(void);
90586523	248
c28f7e56 EP	249	static inline int fsnotify_inode_watches_children(struct inode *inode)
	250	{
	251	/* FS_EVENT_ON_CHILD is set if the inode may care */
	252	if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
	253	return 0;
	254	/* this inode might care about child events, does it care about the
	255	* specific set of events that can happen on a child? */
	256	return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
	257	}
	258
	259	/*
	260	* Update the dentry with a flag indicating the interest of its parent to receive
	261	* filesystem events when those events happens to this dentry->d_inode.
	262	*/
	263	static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
	264	{
	265	struct dentry *parent;
	266
c28f7e56 EP	267	assert_spin_locked(&dentry->d_lock);
c28f7e56 EP	268
b5c84bf6 NP	269	/*
	270	* Serialisation of setting PARENT_WATCHED on the dentries is provided
	271	* by d_lock. If inotify_inode_watched changes after we have taken
	272	* d_lock, the following __fsnotify_update_child_dentry_flags call will
	273	* find our entry, so it will spin until we complete here, and update
	274	* us with the new state.
	275	*/
c28f7e56	276	parent = dentry->d_parent;
e6ce3066	277	if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
c28f7e56 EP	278	dentry->d_flags \|= DCACHE_FSNOTIFY_PARENT_WATCHED;
	279	else
	280	dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
	281	}
	282
	283	/*
	284	* fsnotify_d_instantiate - instantiate a dentry for inode
c28f7e56 EP	285	*/
	286	static inline void __fsnotify_d_instantiate(struct dentry dentry, struct inode inode)
	287	{
	288	if (!inode)
	289	return;
	290
c28f7e56 EP	291	spin_lock(&dentry->d_lock);
	292	__fsnotify_update_dcache_flags(dentry);
	293	spin_unlock(&dentry->d_lock);
	294	}
90586523 EP	295
	296	/* called from fsnotify listeners, such as fanotify or dnotify */
	297
98612952	298	/* create a new group */
0d2e2a1d	299	extern struct fsnotify_group fsnotify_alloc_group(const struct fsnotify_ops ops);
98612952 LS	300	/* get reference to a group */
98612952 LS	301	extern void fsnotify_get_group(struct fsnotify_group *group);
ffab8340	302	/* drop reference on a group from fsnotify_alloc_group */
90586523	303	extern void fsnotify_put_group(struct fsnotify_group *group);
d8153d4d LS	304	/* destroy group */
d8153d4d LS	305	extern void fsnotify_destroy_group(struct fsnotify_group *group);
0a6b6bd5 EP	306	/* fasync handler function */
0a6b6bd5 EP	307	extern int fsnotify_fasync(int fd, struct file *file, int on);
7053aee2 JK	308	/* Free event from memory */
	309	extern void fsnotify_destroy_event(struct fsnotify_group *group,
	310	struct fsnotify_event *event);
a2d8bc6c	311	/* attach the event to the group notification queue */
8ba8fa91 JK	312	extern int fsnotify_add_event(struct fsnotify_group *group,
	313	struct fsnotify_event *event,
	314	int (merge)(struct list_head ,
	315	struct fsnotify_event *));
5838d444 JK	316	/* Remove passed event from groups notification queue */
5838d444 JK	317	extern void fsnotify_remove_event(struct fsnotify_group group, struct fsnotify_event event);
a2d8bc6c EP	318	/* true if the group notification queue is empty */
	319	extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
	320	/* return, but do not dequeue the first event on the notification queue */
8ba8fa91	321	extern struct fsnotify_event fsnotify_peek_first_event(struct fsnotify_group group);
e4aff117	322	/* return AND dequeue the first event on the notification queue */
8ba8fa91	323	extern struct fsnotify_event fsnotify_remove_first_event(struct fsnotify_group group);
a2d8bc6c	324
3be25f49 EP	325	/* functions used to manipulate the marks attached to inodes */
3be25f49 EP	326
0d48b7f0 EP	327	/* run all marks associated with a vfsmount and update mnt->mnt_fsnotify_mask */
0d48b7f0 EP	328	extern void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt);
3be25f49 EP	329	/* run all marks associated with an inode and update inode->i_fsnotify_mask */
3be25f49 EP	330	extern void fsnotify_recalc_inode_mask(struct inode *inode);
841bdc10	331	extern void fsnotify_init_mark(struct fsnotify_mark mark, void (free_mark)(struct fsnotify_mark *mark));
3be25f49	332	/* find (and take a reference) to a mark associated with group and inode */
5444e298	333	extern struct fsnotify_mark fsnotify_find_inode_mark(struct fsnotify_group group, struct inode *inode);
1c529063 EP	334	/* find (and take a reference) to a mark associated with group and vfsmount */
1c529063 EP	335	extern struct fsnotify_mark fsnotify_find_vfsmount_mark(struct fsnotify_group group, struct vfsmount *mnt);
9e1c7432	336	/* copy the values from old into new */
e61ce867	337	extern void fsnotify_duplicate_mark(struct fsnotify_mark new, struct fsnotify_mark old);
33af5e32 EP	338	/* set the ignored_mask of a mark */
33af5e32 EP	339	extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask);
90b1e7a5 EP	340	/* set the mask of a mark (might pin the object into memory */
90b1e7a5 EP	341	extern void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask);
3be25f49	342	/* attach the mark to both the group and the inode */
5444e298 EP	343	extern int fsnotify_add_mark(struct fsnotify_mark mark, struct fsnotify_group group,
5444e298 EP	344	struct inode inode, struct vfsmount mnt, int allow_dups);
d5a335b8 LS	345	extern int fsnotify_add_mark_locked(struct fsnotify_mark mark, struct fsnotify_group group,
d5a335b8 LS	346	struct inode inode, struct vfsmount mnt, int allow_dups);
e2a29943 LS	347	/* given a group and a mark, flag mark to be freed when all references are dropped */
	348	extern void fsnotify_destroy_mark(struct fsnotify_mark *mark,
	349	struct fsnotify_group *group);
d5a335b8 LS	350	extern void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark,
d5a335b8 LS	351	struct fsnotify_group *group);
4d92604c EP	352	/* run all the marks in a group, and clear all of the vfsmount marks */
	353	extern void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group);
	354	/* run all the marks in a group, and clear all of the inode marks */
	355	extern void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group);
	356	/* run all the marks in a group, and clear all of the marks where mark->flags & flags is true*/
	357	extern void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags);
3be25f49 EP	358	/* run all the marks in a group, and flag them to be freed */
3be25f49 EP	359	extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group);
841bdc10 EP	360	extern void fsnotify_get_mark(struct fsnotify_mark *mark);
841bdc10 EP	361	extern void fsnotify_put_mark(struct fsnotify_mark *mark);
164bc619	362	extern void fsnotify_unmount_inodes(struct list_head *list);
3be25f49	363
90586523	364	/* put here because inotify does some weird stuff when destroying watches */
7053aee2 JK	365	extern void fsnotify_init_event(struct fsnotify_event *event,
7053aee2 JK	366	struct inode *to_tell, u32 mask);
b4e4e140	367
90586523 EP	368	#else
90586523 EP	369
c4ec54b4 EP	370	static inline int fsnotify(struct inode to_tell, __u32 mask, void data, int data_is,
	371	const unsigned char *name, u32 cookie)
	372	{
	373	return 0;
	374	}
3be25f49	375
52420392 EP	376	static inline int __fsnotify_parent(struct path path, struct dentry dentry, __u32 mask)
	377	{
	378	return 0;
	379	}
c28f7e56	380
3be25f49 EP	381	static inline void __fsnotify_inode_delete(struct inode *inode)
	382	{}
	383
ca9c726e AG	384	static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
	385	{}
	386
c28f7e56 EP	387	static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
	388	{}
	389
	390	static inline void __fsnotify_d_instantiate(struct dentry dentry, struct inode inode)
	391	{}
	392
47882c6f EP	393	static inline u32 fsnotify_get_cookie(void)
	394	{
	395	return 0;
	396	}
	397
164bc619 EP	398	static inline void fsnotify_unmount_inodes(struct list_head *list)
	399	{}
	400
90586523 EP	401	#endif /* CONFIG_FSNOTIFY */
	402
	403	#endif /* __KERNEL __ */
	404
	405	#endif /* __LINUX_FSNOTIFY_BACKEND_H */