9p: Check for error in return value of v9fs_fid_add

Check if v9fs_fid_add was successful or not based on its
return value.

Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 81f8bbf..1fa5f15 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -470,7 +470,10 @@
 		dentry->d_op = &v9fs_dentry_operations;
 
 	d_instantiate(dentry, inode);
-	v9fs_fid_add(dentry, fid);
+	err = v9fs_fid_add(dentry, fid);
+	if (err < 0)
+		goto error;
+
 	return ofid;
 
 error: