What does Genesis 47:21 mean?

Joseph's plan, provided by the blessing of the Lord, to save Egypt and the surrounding peoples from a seven-year famine has succeeded (Genesis 41:33–36; 55–57). The stores of grain set aside during seven years of plenty before the famine have provided all the food needed to keep the people alive. However, the famine has brought another consequence. Through Joseph, Pharaoh has not simply given food away. Instead, he has sold it, first for money and then for livestock. As the famine raged on, the people gave all their money, herds, and land to Pharaoh's house in exchange for food (Genesis 47:13–20).

Now, through Joseph, Pharaoh has brought all the people of Egypt under servitude. The people have sold their freedom to avoid starvation. Previously free—in the sense of controlling their own money and land and livestock—the Egyptian people are now under a loose form of enslavement, or indentured servitude.