postgres: access to schema objects within a function

Question

Here's my problem:

I have Schema A, owned by User 1, that owns all objects.

I've created schema B, owned by User 2.

I have granted User 2 all privileges to the objects owned by User 1.

When logged in as User2, I have no problem Selecting, Updating, etc... tables owned by User 1. Makes sense.

Now, when logged in as User 2, I want to create a Function that is Selecting some data from tables owned by User 1.

CREATE OR REPLACE FUNCTION -- <-- function owned by User2 (in schema B)
  RETURNS TABLE(
  table columns...)
 AS
$func$ 
BEGIN

        RETURN QUERY
        SELECT * 
        FROM table;  -- <-- table owned by User 1 (in schema A)

END;
$func$
LANGUAGE plpgsql
;

The Selects all by themselves work fine. But when I put them in a Function, I get the error:

ERROR: permission denied for schema schema A
SQL state: 42501

It seems to me that User 2 has the access to User 1's tables...because individual Selects, Inserts, etc... work fine.

It's only when I put these statements within the Function, that i get a permission error.

Obviously I'm missing a permission, or my general design is wrong.

Does anyone have any insight?

thanks so much.

EDIT:

These are the grants i originally issued:

GRANT usage on schema schemaA to user2;
GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA schemaA TO user2;
GRANT USAGE ON ALL SEQUENCES IN SCHEMA schemaA TO user2;
GRANT SELECT, UPDATE ON ALL SEQUENCES IN SCHEMA schemaA TO user2;
GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA schemaA TO user2;

After Issuing this grant, my permission error went away:

Grant ALL on schema schemaA to user2;

So, what is the difference between the the grants I issued versus the Grant ALL statement? Is there a single permission I could have granted individually to make this work?

Thanks.