fsnotify: move mask out of struct fsnotify_event

Common fsnotify_event helpers have no need for the mask field.
It is only used by backend code, so move the field out of the
abstract fsnotify_event struct and into the concrete backend
event structs.

This change packs struct inotify_event_info better on 64bit
machine and will allow us to cram some more fields into
struct fanotify_event_info.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fanotify/fanotify.c

@@ -36,20 +36,22 @@ static bool should_merge(struct fsnotify_event *old_fsn,
 static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
 {
 	struct fsnotify_event *test_event;
+	struct fanotify_event_info *new;
 
 	pr_debug("%s: list=%p event=%p\n", __func__, list, event);
+	new = FANOTIFY_E(event);
 
 	/*
 	 * Don't merge a permission event with any other event so that we know
 	 * the event structure we have created in fanotify_handle_event() is the
 	 * one we should check for permission response.
 	 */
-	if (fanotify_is_perm_event(event->mask))
+	if (fanotify_is_perm_event(new->mask))
 		return 0;
 
 	list_for_each_entry_reverse(test_event, list, list) {
 		if (should_merge(test_event, event)) {
-			test_event->mask |= event->mask;
+			FANOTIFY_E(test_event)->mask |= new->mask;
 			return 1;
 		}
 	}
@@ -173,7 +175,8 @@ struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
 	if (!event)
 		goto out;
 init: __maybe_unused
-	fsnotify_init_event(&event->fse, inode, mask);
+	fsnotify_init_event(&event->fse, inode);
+	event->mask = mask;
 	if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
 		event->pid = get_pid(task_pid(current));
 	else
@@ -280,7 +283,7 @@ static void fanotify_free_event(struct fsnotify_event *fsn_event)
 	event = FANOTIFY_E(fsn_event);
 	path_put(&event->path);
 	put_pid(event->pid);
-	if (fanotify_is_perm_event(fsn_event->mask)) {
+	if (fanotify_is_perm_event(event->mask)) {
 		kmem_cache_free(fanotify_perm_event_cachep,
 				FANOTIFY_PE(fsn_event));
 		return;

fs/notify/fanotify/fanotify.h

@@ -14,6 +14,7 @@ extern struct kmem_cache *fanotify_perm_event_cachep;
  */
 struct fanotify_event_info {
 	struct fsnotify_event fse;
+	u32 mask;
 	/*
 	 * We hold ref to this path so it may be dereferenced at any point
 	 * during this object's lifetime

fs/notify/fanotify/fanotify_user.c

@@ -131,9 +131,9 @@ static int fill_event_metadata(struct fsnotify_group *group,
 	metadata->metadata_len = FAN_EVENT_METADATA_LEN;
 	metadata->vers = FANOTIFY_METADATA_VERSION;
 	metadata->reserved = 0;
-	metadata->mask = fsn_event->mask & FANOTIFY_OUTGOING_EVENTS;
+	metadata->mask = event->mask & FANOTIFY_OUTGOING_EVENTS;
 	metadata->pid = pid_vnr(event->pid);
-	if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW))
+	if (unlikely(event->mask & FAN_Q_OVERFLOW))
 		metadata->fd = FAN_NOFD;
 	else {
 		metadata->fd = create_fd(group, event, file);
@@ -230,7 +230,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 			 fanotify_event_metadata.event_len))
 		goto out_close_fd;
 
-	if (fanotify_is_perm_event(event->mask))
+	if (fanotify_is_perm_event(FANOTIFY_E(event)->mask))
 		FANOTIFY_PE(event)->fd = fd;
 
 	if (fd != FAN_NOFD)
@@ -316,7 +316,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
 		 * Permission events get queued to wait for response.  Other
 		 * events can be destroyed now.
 		 */
-		if (!fanotify_is_perm_event(kevent->mask)) {
+		if (!fanotify_is_perm_event(FANOTIFY_E(kevent)->mask)) {
 			fsnotify_destroy_event(group, kevent);
 		} else {
 			if (ret <= 0) {
@@ -401,7 +401,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
 	 */
 	while (!fsnotify_notify_queue_is_empty(group)) {
 		fsn_event = fsnotify_remove_first_event(group);
-		if (!(fsn_event->mask & FANOTIFY_PERM_EVENTS)) {
+		if (!(FANOTIFY_E(fsn_event)->mask & FANOTIFY_PERM_EVENTS)) {
 			spin_unlock(&group->notification_lock);
 			fsnotify_destroy_event(group, fsn_event);
 			spin_lock(&group->notification_lock);

fs/notify/inotify/inotify.h

@@ -5,6 +5,7 @@
 
 struct inotify_event_info {
 	struct fsnotify_event fse;
+	u32 mask;
 	int wd;
 	u32 sync_cookie;
 	int name_len;

fs/notify/inotify/inotify_fsnotify.c

@@ -43,11 +43,11 @@ static bool event_compare(struct fsnotify_event *old_fsn,
 {
 	struct inotify_event_info *old, *new;
 
-	if (old_fsn->mask & FS_IN_IGNORED)
-		return false;
 	old = INOTIFY_E(old_fsn);
 	new = INOTIFY_E(new_fsn);
-	if ((old_fsn->mask == new_fsn->mask) &&
+	if (old->mask & FS_IN_IGNORED)
+		return false;
+	if ((old->mask == new->mask) &&
 	    (old_fsn->inode == new_fsn->inode) &&
 	    (old->name_len == new->name_len) &&
 	    (!old->name_len || !strcmp(old->name, new->name)))
@@ -114,7 +114,8 @@ int inotify_handle_event(struct fsnotify_group *group,
 	}
 
 	fsn_event = &event->fse;
-	fsnotify_init_event(fsn_event, inode, mask);
+	fsnotify_init_event(fsn_event, inode);
+	event->mask = mask;
 	event->wd = i_mark->wd;
 	event->sync_cookie = cookie;
 	event->name_len = len;

fs/notify/inotify/inotify_user.c

@@ -189,7 +189,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 	 */
 	pad_name_len = round_event_name_len(fsn_event);
 	inotify_event.len = pad_name_len;
-	inotify_event.mask = inotify_mask_to_arg(fsn_event->mask);
+	inotify_event.mask = inotify_mask_to_arg(event->mask);
 	inotify_event.wd = event->wd;
 	inotify_event.cookie = event->sync_cookie;
 
@@ -634,7 +634,8 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events)
 		return ERR_PTR(-ENOMEM);
 	}
 	group->overflow_event = &oevent->fse;
-	fsnotify_init_event(group->overflow_event, NULL, FS_Q_OVERFLOW);
+	fsnotify_init_event(group->overflow_event, NULL);
+	oevent->mask = FS_Q_OVERFLOW;
 	oevent->wd = -1;
 	oevent->sync_cookie = 0;
 	oevent->name_len = 0;

fs/notify/notification.c

@@ -71,7 +71,7 @@ void fsnotify_destroy_event(struct fsnotify_group *group,
 			    struct fsnotify_event *event)
 {
 	/* Overflow events are per-group and we don't want to free them */
-	if (!event || event->mask == FS_Q_OVERFLOW)
+	if (!event || event == group->overflow_event)
 		return;
 	/*
 	 * If the event is still queued, we have a problem... Do an unreliable
@@ -194,23 +194,3 @@ void fsnotify_flush_notify(struct fsnotify_group *group)
 	}
 	spin_unlock(&group->notification_lock);
 }
-
-/*
- * fsnotify_create_event - Allocate a new event which will be sent to each
- * group's handle_event function if the group was interested in this
- * particular event.
- *
- * @inode the inode which is supposed to receive the event (sometimes a
- *	parent of the inode to which the event happened.
- * @mask what actually happened.
- * @data pointer to the object which was actually affected
- * @data_type flag indication if the data is a file, path, inode, nothing...
- * @name the filename, if available
- */
-void fsnotify_init_event(struct fsnotify_event *event, struct inode *inode,
-			 u32 mask)
-{
-	INIT_LIST_HEAD(&event->list);
-	event->inode = inode;
-	event->mask = mask;
-}

include/linux/fsnotify_backend.h

@@ -135,7 +135,6 @@ 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 */
 };
 
 /*
@@ -485,9 +484,12 @@ 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);
 
-/* 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);
+static inline void fsnotify_init_event(struct fsnotify_event *event,
+				       struct inode *inode)
+{
+	INIT_LIST_HEAD(&event->list);
+	event->inode = inode;
+}
 
 #else