fsnotify: fold fsnotify() call into fsnotify_parent()

All (two) callers of fsnotify_parent() also call fsnotify() to notify
the child inode. Move the second fsnotify() call into fsnotify_parent().

This will allow more flexibility in making decisions about which of the
two event falvors should be sent.

Using 'goto notify_child' in the inline helper seems a bit strange, but
it mimics the code in __fsnotify_parent() for clarity and the goto
pattern will become less strage after following patches are applied.

Link: https://lore.kernel.org/r/20200708111156.24659-2-amir73il@gmail.comSigned-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/fsnotify.c

@@ -142,16 +142,20 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
 	spin_unlock(&inode->i_lock);
 }
 
-/* Notify this dentry's parent about a child's events. */
+/*
+ * Notify this dentry's parent about a child's events with child name info
+ * if parent is watching.
+ * Notify also the child without name info if child inode is watching.
+ */
 int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
-		    int data_type)
+		      int data_type)
 {
 	struct dentry *parent;
 	struct inode *p_inode;
 	int ret = 0;
 
 	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
-		return 0;
+		goto notify_child;
 
 	parent = dget_parent(dentry);
 	p_inode = parent->d_inode;
@@ -161,18 +165,23 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
 	} else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) {
 		struct name_snapshot name;
 
-		/* we are notifying a parent so come up with the new mask which
-		 * specifies these are events which came from a child. */
-		mask |= FS_EVENT_ON_CHILD;
-
+		/*
+		 * We are notifying a parent, so set a flag in mask to inform
+		 * backend that event has information about a child entry.
+		 */
 		take_dentry_name_snapshot(&name, dentry);
-		ret = fsnotify(p_inode, mask, data, data_type, &name.name, 0);
+		ret = fsnotify(p_inode, mask | FS_EVENT_ON_CHILD, data,
+			       data_type, &name.name, 0);
 		release_dentry_name_snapshot(&name);
 	}
 
 	dput(parent);
 
-	return ret;
+	if (ret)
+		return ret;
+
+notify_child:
+	return fsnotify(d_inode(dentry), mask, data, data_type, NULL, 0);
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 

include/linux/fsnotify.h

@@ -48,44 +48,37 @@ static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
 static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
 				  const void *data, int data_type)
 {
+	struct inode *inode = d_inode(dentry);
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= FS_ISDIR;
+
 	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
-		return 0;
+		goto notify_child;
 
 	return __fsnotify_parent(dentry, mask, data, data_type);
+
+notify_child:
+	return fsnotify(inode, mask, data, data_type, NULL, 0);
 }
 
 /*
- * Simple wrappers to consolidate calls fsnotify_parent()/fsnotify() when
- * an event is on a file/dentry.
+ * Simple wrappers to consolidate calls to fsnotify_parent() when an event
+ * is on a file/dentry.
  */
 static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
 {
-	struct inode *inode = d_inode(dentry);
-
-	if (S_ISDIR(inode->i_mode))
-		mask |= FS_ISDIR;
-
-	fsnotify_parent(dentry, mask, inode, FSNOTIFY_EVENT_INODE);
-	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+	fsnotify_parent(dentry, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE);
 }
 
 static inline int fsnotify_file(struct file *file, __u32 mask)
 {
 	const struct path *path = &file->f_path;
-	struct inode *inode = file_inode(file);
-	int ret;
 
 	if (file->f_mode & FMODE_NONOTIFY)
 		return 0;
 
-	if (S_ISDIR(inode->i_mode))
-		mask |= FS_ISDIR;
-
-	ret = fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
-	if (ret)
-		return ret;
-
-	return fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+	return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
 }
 
 /* Simple call site for access decisions */