Do we need to meet all of them in order to have knowledge? Even if we have a justified true belief, are there any criteria missing, as Gettier seems to have thought?

1. Knowledge & Knowing
In the Mediations, Descartes was concerned to find knowledge that was true, certain, and well-justified. Three centuries later, A. J. Ayer wrote that to know something is have a justified true belief about it. Gettier objected to Ayer’s characterization of knowledge by offering a counterexample.

In your view, are the criteria of justification, truth, and conviction necessary and sufficient conditions for having knowledge? In other words, can we claim to know something if we meet Ayer’s criteria? Do we need to meet all of them in order to have knowledge? Even if we have a justified true belief, are there any criteria missing, as Gettier seems to have thought?

Answer this question succinctly as possible. Your answer should (1) explain
what Ayer means by justification, truth, and conviction (belief), (2) the details and reasons for Gettier’s objection, and (3) your assessment of the debate. Be sure to offer reasons for and against your view, providing your own examples as needed to clarify your meaning.