fsnotify: include pathnames with entries when possible

When inotify wants to send events to a directory about a child it includes
the name of the original file.  This patch collects that filename and makes
it available for notification.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

fs/notify/fsnotify.c

@@ -114,7 +114,8 @@ void __fsnotify_parent(struct dentry *dentry, __u32 mask)
 		 * specifies these are events which came from a child. */
 		mask |= FS_EVENT_ON_CHILD;
 
-		fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE);
+		fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
+			 dentry->d_name.name);
 		dput(parent);
 	}
 
@@ -131,7 +132,7 @@ EXPORT_SYMBOL_GPL(__fsnotify_parent);
  * out to all of the registered fsnotify_group.  Those groups can then use the
  * notification event in whatever means they feel necessary.
  */
-void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
+void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name)
 {
 	struct fsnotify_group *group;
 	struct fsnotify_event *event = NULL;
@@ -156,7 +157,7 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
 			if (!group->ops->should_send_event(group, to_tell, mask))
 				continue;
 			if (!event) {
-				event = fsnotify_create_event(to_tell, mask, data, data_is);
+				event = fsnotify_create_event(to_tell, mask, data, data_is, file_name);
 				/* shit, we OOM'd and now we can't tell, maybe
 				 * someday someone else will want to do something
 				 * here */

fs/notify/notification.c

@@ -78,6 +78,7 @@ void fsnotify_put_event(struct fsnotify_event *event)
 		if (event->data_type == FSNOTIFY_EVENT_PATH)
 			path_put(&event->path);
 
+		kfree(event->file_name);
 		kmem_cache_free(fsnotify_event_cachep, event);
 	}
 }
@@ -262,6 +263,9 @@ static void initialize_event(struct fsnotify_event *event)
 	event->data_type = FSNOTIFY_EVENT_NONE;
 
 	event->to_tell = NULL;
+
+	event->file_name = NULL;
+	event->name_len = 0;
 }
 
 /*
@@ -274,9 +278,10 @@ static void initialize_event(struct fsnotify_event *event)
  * @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
  */
 struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
-					     void *data, int data_type)
+					     void *data, int data_type, const char *name)
 {
 	struct fsnotify_event *event;
 
@@ -285,6 +290,15 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
 		return NULL;
 
 	initialize_event(event);
+
+	if (name) {
+		event->file_name = kstrdup(name, GFP_KERNEL);
+		if (!event->file_name) {
+			kmem_cache_free(fsnotify_event_cachep, event);
+			return NULL;
+		}
+		event->name_len = strlen(event->file_name);
+	}
 	event->to_tell = to_tell;
 
 	switch (data_type) {

include/linux/fsnotify.h

@@ -58,7 +58,7 @@ static inline void fsnotify_link_count(struct inode *inode)
 {
 	inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
 
-	fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL);
 }
 
 /*
@@ -91,8 +91,8 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 	inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name,
 				  source);
 
-	fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE);
-	fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE);
+	fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE, old_name);
+	fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE, new_name);
 
 	if (target) {
 		inotify_inode_queue_event(target, IN_DELETE_SELF, 0, NULL, NULL);
@@ -104,7 +104,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 
 	if (source) {
 		inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL, NULL);
-		fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE);
+		fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL);
 	}
 	audit_inode_child(new_name, moved, new_dir);
 }
@@ -138,7 +138,7 @@ static inline void fsnotify_inoderemove(struct inode *inode)
 	inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL, NULL);
 	inotify_inode_is_dead(inode);
 
-	fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL);
 	__fsnotify_inode_delete(inode);
 }
 
@@ -151,7 +151,7 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 				  dentry->d_inode);
 	audit_inode_child(dentry->d_name.name, dentry, inode);
 
-	fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name);
 }
 
 /*
@@ -166,7 +166,7 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct
 	fsnotify_link_count(inode);
 	audit_inode_child(new_dentry->d_name.name, new_dentry, dir);
 
-	fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name);
 }
 
 /*
@@ -180,7 +180,7 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 	inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode);
 	audit_inode_child(dentry->d_name.name, dentry, inode);
 
-	fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name);
 }
 
 /*
@@ -197,7 +197,7 @@ static inline void fsnotify_access(struct dentry *dentry)
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
-	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL);
 }
 
 /*
@@ -214,7 +214,7 @@ static inline void fsnotify_modify(struct dentry *dentry)
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
-	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL);
 }
 
 /*
@@ -231,7 +231,7 @@ static inline void fsnotify_open(struct dentry *dentry)
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
-	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL);
 }
 
 /*
@@ -250,7 +250,7 @@ static inline void fsnotify_close(struct file *file)
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
-	fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE);
+	fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL);
 }
 
 /*
@@ -267,7 +267,7 @@ static inline void fsnotify_xattr(struct dentry *dentry)
 	inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 	fsnotify_parent(dentry, mask);
-	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL);
 }
 
 /*
@@ -303,7 +303,7 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 		inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
 
 		fsnotify_parent(dentry, mask);
-		fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE);
+		fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL);
 	}
 }
 

include/linux/fsnotify_backend.h

@@ -192,6 +192,9 @@ struct fsnotify_event {
 	int data_type;		/* which of the above union we have */
 	atomic_t refcnt;	/* how many groups still are using/need to send this event */
 	__u32 mask;		/* the type of access, bitwise OR for FS_* event types */
+
+	char *file_name;
+	size_t name_len;
 };
 
 /*
@@ -224,7 +227,7 @@ struct fsnotify_mark_entry {
 /* called from the vfs helpers */
 
 /* main fsnotify call to send events */
-extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is);
+extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *name);
 extern void __fsnotify_parent(struct dentry *dentry, __u32 mask);
 extern void __fsnotify_inode_delete(struct inode *inode);
 
@@ -319,10 +322,12 @@ extern void fsnotify_put_mark(struct fsnotify_mark_entry *entry);
 
 /* put here because inotify does some weird stuff when destroying watches */
 extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
-						    void *data, int data_is);
+						    void *data, int data_is, const char *name);
+
 #else
 
-static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
+static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+			    const char *name);
 {}
 
 static inline void __fsnotify_parent(struct dentry *dentry, __u32 mask)