---

yaml
---
r: 377461
b: refs/heads/master
c: 605c912
h: refs/heads/master
i:
  377459: 5eed688
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 33f1a63ae84dfd9ad298cf275b8f1887043ced36
+refs/heads/master: 605c912bb843c024b1ed173dc427cd5c08e5d54d

trunk/fs/ubifs/dir.c

@@ -365,6 +365,24 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
 		 */
 		return 0;
 
+	if (file->f_version == 0) {
+		/*
+		 * The file was seek'ed, which means that @file->private_data
+		 * is now invalid. This may also be just the first
+		 * 'ubifs_readdir()' invocation, in which case
+		 * @file->private_data is NULL, and the below code is
+		 * basically a no-op.
+		 */
+		kfree(file->private_data);
+		file->private_data = NULL;
+	}
+
+	/*
+	 * 'generic_file_llseek()' unconditionally sets @file->f_version to
+	 * zero, and we use this for detecting whether the file was seek'ed.
+	 */
+	file->f_version = 1;
+
 	/* File positions 0 and 1 correspond to "." and ".." */
 	if (pos == 0) {
 		ubifs_assert(!file->private_data);
@@ -438,6 +456,14 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
 		file->f_pos = pos = key_hash_flash(c, &dent->key);
 		file->private_data = dent;
 		cond_resched();
+
+		if (file->f_version == 0)
+			/*
+			 * The file was seek'ed meanwhile, lets return and start
+			 * reading direntries from the new position on the next
+			 * invocation.
+			 */
+			return 0;
 	}
 
 out:
@@ -448,15 +474,13 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
 
 	kfree(file->private_data);
 	file->private_data = NULL;
+	/* 2 is a special value indicating that there are no more direntries */
 	file->f_pos = 2;
 	return 0;
 }
 
-/* If a directory is seeked, we have to free saved readdir() state */
 static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int whence)
 {
-	kfree(file->private_data);
-	file->private_data = NULL;
 	return generic_file_llseek(file, offset, whence);
 }