fsnotify: take inode->i_lock inside fsnotify_find_mark_entry()

All callers to fsnotify_find_mark_entry() except one take and
release inode->i_lock around the call.  Take the lock inside
fsnotify_find_mark_entry() instead.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

fs/notify/dnotify/dnotify.c

@@ -95,11 +95,7 @@ static int dnotify_handle_event(struct fsnotify_group *group,
 
 	to_tell = event->to_tell;
 
-	spin_lock(&to_tell->i_lock);
 	fsn_mark = fsnotify_find_mark(group, to_tell);
-	spin_unlock(&to_tell->i_lock);
-
-	/* unlikely since we alreay passed dnotify_should_send_event() */
 	if (unlikely(!fsn_mark))
 		return 0;
 	dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
@@ -147,11 +143,7 @@ static bool dnotify_should_send_event(struct fsnotify_group *group,
 	if (!S_ISDIR(inode->i_mode))
 		return false;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
-
-	/* no mark means no dnotify watch */
 	if (!fsn_mark)
 		return false;
 
@@ -201,9 +193,7 @@ void dnotify_flush(struct file *filp, fl_owner_t id)
 	if (!S_ISDIR(inode->i_mode))
 		return;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(dnotify_group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return;
 	dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
@@ -356,9 +346,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
 	mutex_lock(&dnotify_mark_mutex);
 
 	/* add the new_fsn_mark or find an old one. */
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(dnotify_group, inode);
-	spin_unlock(&inode->i_lock);
 	if (fsn_mark) {
 		dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
 		spin_lock(&fsn_mark->lock);

fs/notify/inode_mark.c

@@ -261,12 +261,8 @@ void fsnotify_clear_marks_by_inode(struct inode *inode)
 	}
 }
 
-/*
- * given a group and inode, find the mark associated with that combination.
- * if found take a reference to that mark and return it, else return NULL
- */
-struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
-					 struct inode *inode)
+static struct fsnotify_mark *fsnotify_find_mark_locked(struct fsnotify_group *group,
+						       struct inode *inode)
 {
 	struct fsnotify_mark *mark;
 	struct hlist_node *pos;
@@ -282,6 +278,22 @@ struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
 	return NULL;
 }
 
+/*
+ * given a group and inode, find the mark associated with that combination.
+ * if found take a reference to that mark and return it, else return NULL
+ */
+struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group,
+					 struct inode *inode)
+{
+	struct fsnotify_mark *mark;
+
+	spin_lock(&inode->i_lock);
+	mark = fsnotify_find_mark_locked(group, inode);
+	spin_unlock(&inode->i_lock);
+
+	return mark;
+}
+
 void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old)
 {
 	assert_spin_locked(&old->lock);
@@ -349,7 +361,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
 	spin_lock(&inode->i_lock);
 
 	if (!allow_dups)
-		lmark = fsnotify_find_mark(group, inode);
+		lmark = fsnotify_find_mark_locked(group, inode);
 	if (!lmark) {
 		mark->group = group;
 		mark->i.inode = inode;

fs/notify/inotify/inotify_fsnotify.c

@@ -97,9 +97,7 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
 
 	to_tell = event->to_tell;
 
-	spin_lock(&to_tell->i_lock);
 	fsn_mark = fsnotify_find_mark(group, to_tell);
-	spin_unlock(&to_tell->i_lock);
 	/* race with watch removal?  We already passes should_send */
 	if (unlikely(!fsn_mark))
 		return 0;
@@ -147,9 +145,7 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
 	struct fsnotify_mark *fsn_mark;
 	bool send;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return false;
 

fs/notify/inotify/inotify_user.c

@@ -566,9 +566,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 	if (unlikely(!mask))
 		return -EINVAL;
 
-	spin_lock(&inode->i_lock);
 	fsn_mark = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!fsn_mark)
 		return -ENOENT;
 

kernel/audit_tree.c

@@ -360,9 +360,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 	struct node *p;
 	int n;
 
-	spin_lock(&inode->i_lock);
 	old_entry = fsnotify_find_mark(audit_tree_group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!old_entry)
 		return create_chunk(inode, tree);
 

kernel/audit_watch.c

@@ -101,10 +101,7 @@ static inline struct audit_parent *audit_find_parent(struct inode *inode)
 	struct audit_parent *parent = NULL;
 	struct fsnotify_mark *entry;
 
-	spin_lock(&inode->i_lock);
 	entry = fsnotify_find_mark(audit_watch_group, inode);
-	spin_unlock(&inode->i_lock);
-
 	if (entry)
 		parent = container_of(entry, struct audit_parent, mark);
 
@@ -520,9 +517,7 @@ static bool audit_watch_should_send_event(struct fsnotify_group *group, struct i
 	struct fsnotify_mark *entry;
 	bool send;
 
-	spin_lock(&inode->i_lock);
 	entry = fsnotify_find_mark(group, inode);
-	spin_unlock(&inode->i_lock);
 	if (!entry)
 		return false;