diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index ed424d708e69..1d40f2bd1970 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -2165,8 +2165,10 @@ static ssize_t reiserfs_quota_write(struct super_block *sb, int type,
 		blk++;
 	}
 out:
-	if (len == towrite)
+	if (len == towrite) {
+		mutex_unlock(&inode->i_mutex);
 		return err;
+	}
 	if (inode->i_size < off + len - towrite)
 		i_size_write(inode, off + len - towrite);
 	inode->i_version++;