Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 865 insertions, 0 deletions

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
new file mode 100644
index 000000000..c0892d75c
--- /dev/null
+++ b/include/linux/fsnotify_backend.h
@@ -0,0 +1,865 @@
+/* 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>
+#include <linux/mempool.h>
+#include <linux/sched/mm.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_ERROR		0x00008000	/* Filesystem Error (fanotify) */
+
+/*
+ * FS_IN_IGNORED overloads FS_ERROR.  It is only used internally by inotify
+ * which does not support FS_ERROR.
+ */
+#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 */
+
+/*
+ * 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_RENAME		0x10000000	/* File was renamed */
+#define FS_DN_MULTISHOT		0x20000000	/* dnotify multishot */
+#define FS_ISDIR		0x40000000	/* event occurred against dir */
+
+#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 | FS_RENAME)
+
+#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_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
+			     FS_ERROR)
+
+/* Extra flags that may be reported with event or control handling of events */
+#define ALL_FSNOTIFY_FLAGS  (FS_ISDIR | FS_EVENT_ON_CHILD | FS_DN_MULTISHOT)
+
+#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.
+ *		Either @inode or @dir must be non-NULL.
+ * @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_group *group, 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;
+};
+
+/*
+ * 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 */
+
+#define FSNOTIFY_GROUP_USER	0x01 /* user allocated group */
+#define FSNOTIFY_GROUP_DUPS	0x02 /* allow multiple marks per object */
+#define FSNOTIFY_GROUP_NOFS	0x04 /* group lock is not direct reclaim safe */
+	int flags;
+	unsigned int owner_flags;	/* stored flags of mark_mutex owner */
+
+	/* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
+	struct mutex mark_mutex;	/* protect marks_list */
+	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 {
+			/* Hash table of events for merge */
+			struct hlist_head *merge_hash;
+			/* 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() */
+			struct ucounts *ucounts;
+			mempool_t error_events_pool;
+		} fanotify_data;
+#endif /* CONFIG_FANOTIFY */
+	};
+};
+
+/*
+ * These helpers are used to prevent deadlock when reclaiming inodes with
+ * evictable marks of the same group that is allocating a new mark.
+ */
+static inline void fsnotify_group_lock(struct fsnotify_group *group)
+{
+	mutex_lock(&group->mark_mutex);
+	if (group->flags & FSNOTIFY_GROUP_NOFS)
+		group->owner_flags = memalloc_nofs_save();
+}
+
+static inline void fsnotify_group_unlock(struct fsnotify_group *group)
+{
+	if (group->flags & FSNOTIFY_GROUP_NOFS)
+		memalloc_nofs_restore(group->owner_flags);
+	mutex_unlock(&group->mark_mutex);
+}
+
+static inline void fsnotify_group_assert_locked(struct fsnotify_group *group)
+{
+	WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
+	if (group->flags & FSNOTIFY_GROUP_NOFS)
+		WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
+}
+
+/* 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,
+	FSNOTIFY_EVENT_DENTRY,
+	FSNOTIFY_EVENT_ERROR,
+};
+
+struct fs_error_report {
+	int error;
+	struct inode *inode;
+	struct super_block *sb;
+};
+
+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_DENTRY:
+		return d_inode(data);
+	case FSNOTIFY_EVENT_PATH:
+		return d_inode(((const struct path *)data)->dentry);
+	case FSNOTIFY_EVENT_ERROR:
+		return ((struct fs_error_report *)data)->inode;
+	default:
+		return NULL;
+	}
+}
+
+static inline struct dentry *fsnotify_data_dentry(const void *data, int data_type)
+{
+	switch (data_type) {
+	case FSNOTIFY_EVENT_DENTRY:
+		/* Non const is needed for dget() */
+		return (struct dentry *)data;
+	case FSNOTIFY_EVENT_PATH:
+		return ((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;
+	}
+}
+
+static inline struct super_block *fsnotify_data_sb(const void *data,
+						   int data_type)
+{
+	switch (data_type) {
+	case FSNOTIFY_EVENT_INODE:
+		return ((struct inode *)data)->i_sb;
+	case FSNOTIFY_EVENT_DENTRY:
+		return ((struct dentry *)data)->d_sb;
+	case FSNOTIFY_EVENT_PATH:
+		return ((const struct path *)data)->dentry->d_sb;
+	case FSNOTIFY_EVENT_ERROR:
+		return ((struct fs_error_report *) data)->sb;
+	default:
+		return NULL;
+	}
+}
+
+static inline struct fs_error_report *fsnotify_data_error_report(
+							const void *data,
+							int data_type)
+{
+	switch (data_type) {
+	case FSNOTIFY_EVENT_ERROR:
+		return (struct fs_error_report *) data;
+	default:
+		return NULL;
+	}
+}
+
+/*
+ * Index to merged marks iterator array that correlates to a type of watch.
+ * The type of watched object can be deduced from the iterator type, but not
+ * the other way around, because an event can match different watched objects
+ * of the same object type.
+ * For example, both parent and child are watching an object of type inode.
+ */
+enum fsnotify_iter_type {
+	FSNOTIFY_ITER_TYPE_INODE,
+	FSNOTIFY_ITER_TYPE_VFSMOUNT,
+	FSNOTIFY_ITER_TYPE_SB,
+	FSNOTIFY_ITER_TYPE_PARENT,
+	FSNOTIFY_ITER_TYPE_INODE2,
+	FSNOTIFY_ITER_TYPE_COUNT
+};
+
+/* The type of object that a mark is attached to */
+enum fsnotify_obj_type {
+	FSNOTIFY_OBJ_TYPE_ANY = -1,
+	FSNOTIFY_OBJ_TYPE_INODE,
+	FSNOTIFY_OBJ_TYPE_VFSMOUNT,
+	FSNOTIFY_OBJ_TYPE_SB,
+	FSNOTIFY_OBJ_TYPE_COUNT,
+	FSNOTIFY_OBJ_TYPE_DETACHED = FSNOTIFY_OBJ_TYPE_COUNT
+};
+
+static inline bool fsnotify_valid_obj_type(unsigned int obj_type)
+{
+	return (obj_type < FSNOTIFY_OBJ_TYPE_COUNT);
+}
+
+struct fsnotify_iter_info {
+	struct fsnotify_mark *marks[FSNOTIFY_ITER_TYPE_COUNT];
+	struct fsnotify_group *current_group;
+	unsigned int report_mask;
+	int srcu_idx;
+};
+
+static inline bool fsnotify_iter_should_report_type(
+		struct fsnotify_iter_info *iter_info, int iter_type)
+{
+	return (iter_info->report_mask & (1U << iter_type));
+}
+
+static inline void fsnotify_iter_set_report_type(
+		struct fsnotify_iter_info *iter_info, int iter_type)
+{
+	iter_info->report_mask |= (1U << iter_type);
+}
+
+static inline struct fsnotify_mark *fsnotify_iter_mark(
+		struct fsnotify_iter_info *iter_info, int iter_type)
+{
+	if (fsnotify_iter_should_report_type(iter_info, iter_type))
+		return iter_info->marks[iter_type];
+	return NULL;
+}
+
+static inline int fsnotify_iter_step(struct fsnotify_iter_info *iter, int type,
+				     struct fsnotify_mark **markp)
+{
+	while (type < FSNOTIFY_ITER_TYPE_COUNT) {
+		*markp = fsnotify_iter_mark(iter, type);
+		if (*markp)
+			break;
+		type++;
+	}
+	return type;
+}
+
+#define FSNOTIFY_ITER_FUNCS(name, NAME) \
+static inline struct fsnotify_mark *fsnotify_iter_##name##_mark( \
+		struct fsnotify_iter_info *iter_info) \
+{ \
+	return fsnotify_iter_mark(iter_info, FSNOTIFY_ITER_TYPE_##NAME); \
+}
+
+FSNOTIFY_ITER_FUNCS(inode, INODE)
+FSNOTIFY_ITER_FUNCS(parent, PARENT)
+FSNOTIFY_ITER_FUNCS(vfsmount, VFSMOUNT)
+FSNOTIFY_ITER_FUNCS(sb, SB)
+
+#define fsnotify_foreach_iter_type(type) \
+	for (type = 0; type < FSNOTIFY_ITER_TYPE_COUNT; type++)
+#define fsnotify_foreach_iter_mark_type(iter, mark, type) \
+	for (type = 0; \
+	     type = fsnotify_iter_step(iter, type, &mark), \
+	     type < FSNOTIFY_ITER_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
+#define FSNOTIFY_CONN_FLAG_HAS_IREF	0x02
+	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 and flags to ignore [mark->lock, group->mark_mutex] */
+	__u32 ignore_mask;
+	/* General fsnotify mark flags */
+#define FSNOTIFY_MARK_FLAG_ALIVE		0x0001
+#define FSNOTIFY_MARK_FLAG_ATTACHED		0x0002
+	/* inotify mark flags */
+#define FSNOTIFY_MARK_FLAG_EXCL_UNLINK		0x0010
+#define FSNOTIFY_MARK_FLAG_IN_ONESHOT		0x0020
+	/* fanotify mark flags */
+#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY	0x0100
+#define FSNOTIFY_MARK_FLAG_NO_IREF		0x0200
+#define FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS	0x0400
+	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,
+				int flags);
+/* 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_insert_event(struct fsnotify_group *group,
+				 struct fsnotify_event *event,
+				 int (*merge)(struct fsnotify_group *,
+					      struct fsnotify_event *),
+				 void (*insert)(struct fsnotify_group *,
+						struct fsnotify_event *));
+
+static inline int fsnotify_add_event(struct fsnotify_group *group,
+				     struct fsnotify_event *event,
+				     int (*merge)(struct fsnotify_group *,
+						  struct fsnotify_event *))
+{
+	return fsnotify_insert_event(group, event, merge, NULL);
+}
+
+/* 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);
+}
+
+static inline bool fsnotify_is_overflow_event(u32 mask)
+{
+	return mask & FS_Q_OVERFLOW;
+}
+
+static inline bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group)
+{
+	assert_spin_locked(&group->notification_lock);
+
+	return list_empty(&group->notification_list);
+}
+
+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 */
+
+/*
+ * Canonical "ignore mask" including event flags.
+ *
+ * Note the subtle semantic difference from the legacy ->ignored_mask.
+ * ->ignored_mask traditionally only meant which events should be ignored,
+ * while ->ignore_mask also includes flags regarding the type of objects on
+ * which events should be ignored.
+ */
+static inline __u32 fsnotify_ignore_mask(struct fsnotify_mark *mark)
+{
+	__u32 ignore_mask = mark->ignore_mask;
+
+	/* The event flags in ignore mask take effect */
+	if (mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
+		return ignore_mask;
+
+	/*
+	 * Legacy behavior:
+	 * - Always ignore events on dir
+	 * - Ignore events on child if parent is watching children
+	 */
+	ignore_mask |= FS_ISDIR;
+	ignore_mask &= ~FS_EVENT_ON_CHILD;
+	ignore_mask |= mark->mask & FS_EVENT_ON_CHILD;
+
+	return ignore_mask;
+}
+
+/* Legacy ignored_mask - only event types to ignore */
+static inline __u32 fsnotify_ignored_events(struct fsnotify_mark *mark)
+{
+	return mark->ignore_mask & ALL_FSNOTIFY_EVENTS;
+}
+
+/*
+ * Check if mask (or ignore mask) should be applied depending if victim is a
+ * directory and whether it is reported to a watching parent.
+ */
+static inline bool fsnotify_mask_applicable(__u32 mask, bool is_dir,
+					    int iter_type)
+{
+	/* Should mask be applied to a directory? */
+	if (is_dir && !(mask & FS_ISDIR))
+		return false;
+
+	/* Should mask be applied to a child? */
+	if (iter_type == FSNOTIFY_ITER_TYPE_PARENT &&
+	    !(mask & FS_EVENT_ON_CHILD))
+		return false;
+
+	return true;
+}
+
+/*
+ * Effective ignore mask taking into account if event victim is a
+ * directory and whether it is reported to a watching parent.
+ */
+static inline __u32 fsnotify_effective_ignore_mask(struct fsnotify_mark *mark,
+						   bool is_dir, int iter_type)
+{
+	__u32 ignore_mask = fsnotify_ignored_events(mark);
+
+	if (!ignore_mask)
+		return 0;
+
+	/* For non-dir and non-child, no need to consult the event flags */
+	if (!is_dir && iter_type != FSNOTIFY_ITER_TYPE_PARENT)
+		return ignore_mask;
+
+	ignore_mask = fsnotify_ignore_mask(mark);
+	if (!fsnotify_mask_applicable(ignore_mask, is_dir, iter_type))
+		return 0;
+
+	return ignore_mask & ALL_FSNOTIFY_EVENTS;
+}
+
+/* Get mask for calculating object interest taking ignore mask into account */
+static inline __u32 fsnotify_calc_mask(struct fsnotify_mark *mark)
+{
+	__u32 mask = mark->mask;
+
+	if (!fsnotify_ignored_events(mark))
+		return mask;
+
+	/* Interest in FS_MODIFY may be needed for clearing ignore mask */
+	if (!(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
+		mask |= FS_MODIFY;
+
+	/*
+	 * If mark is interested in ignoring events on children, the object must
+	 * show interest in those events for fsnotify_parent() to notice it.
+	 */
+	return mask | mark->ignore_mask;
+}
+
+/* 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);
+/* attach the mark to the object */
+extern int fsnotify_add_mark(struct fsnotify_mark *mark,
+			     fsnotify_connp_t *connp, unsigned int obj_type,
+			     int add_flags, __kernel_fsid_t *fsid);
+extern int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
+				    fsnotify_connp_t *connp,
+				    unsigned int obj_type, int add_flags,
+				    __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 add_flags)
+{
+	return fsnotify_add_mark(mark, &inode->i_fsnotify_marks,
+				 FSNOTIFY_OBJ_TYPE_INODE, add_flags, NULL);
+}
+static inline int fsnotify_add_inode_mark_locked(struct fsnotify_mark *mark,
+						 struct inode *inode,
+						 int add_flags)
+{
+	return fsnotify_add_mark_locked(mark, &inode->i_fsnotify_marks,
+					FSNOTIFY_OBJ_TYPE_INODE, add_flags,
+					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);
+/* Clear all of the marks of a group attached to a given object type */
+extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
+					  unsigned int obj_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);
+}
+/* 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);
+}
+/* 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);
+}
+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)
+{
+	INIT_LIST_HEAD(&event->list);
+}
+
+#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 */