fsnotify: call fsnotify_parent in perm events

fsnotify perm events do not call fsnotify parent.  That means you cannot
register a perm event on a directory and enforce permissions on all inodes in
that directory.  This patch fixes that situation.

Signed-off-by: Eric Paris <eparis@redhat.com>

fs/notify/fsnotify.c

@@ -84,16 +84,17 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 }
 
 /* Notify this dentry's parent about a child's events. */
-void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 {
 	struct dentry *parent;
 	struct inode *p_inode;
+	int ret = 0;
 
 	if (!dentry)
 		dentry = path->dentry;
 
 	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
-		return;
+		return 0;
 
 	parent = dget_parent(dentry);
 	p_inode = parent->d_inode;
@@ -106,14 +107,16 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 		mask |= FS_EVENT_ON_CHILD;
 
 		if (path)
-			fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
-				 dentry->d_name.name, 0);
+			ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
+				       dentry->d_name.name, 0);
 		else
-			fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
-				 dentry->d_name.name, 0);
+			ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
+				       dentry->d_name.name, 0);
 	}
 
 	dput(parent);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 

include/linux/fsnotify.h

@@ -26,12 +26,12 @@ static inline void fsnotify_d_instantiate(struct dentry *dentry,
 }
 
 /* Notify this dentry's parent about a child's events. */
-static inline void fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+static inline int fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 {
 	if (!dentry)
 		dentry = path->dentry;
 
-	__fsnotify_parent(path, dentry, mask);
+	return __fsnotify_parent(path, dentry, mask);
 }
 
 /* simple call site for access decisions */
@@ -40,6 +40,7 @@ static inline int fsnotify_perm(struct file *file, int mask)
 	struct path *path = &file->f_path;
 	struct inode *inode = path->dentry->d_inode;
 	__u32 fsnotify_mask = 0;
+	int ret;
 
 	if (file->f_mode & FMODE_NONOTIFY)
 		return 0;
@@ -52,6 +53,10 @@ static inline int fsnotify_perm(struct file *file, int mask)
 	else
 		BUG();
 
+	ret = fsnotify_parent(path, NULL, fsnotify_mask);
+	if (ret)
+		return ret;
+
 	return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 }
 

include/linux/fsnotify_backend.h

@@ -304,7 +304,7 @@ struct fsnotify_mark {
 /* 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 void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
+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);
@@ -433,8 +433,10 @@ static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int da
 	return 0;
 }
 
-static inline void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
-{}
+static inline int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
+{
+	return 0;
+}
 
 static inline void __fsnotify_inode_delete(struct inode *inode)
 {}