7.1 Function of Buffer7.2 Structure of Buffer7.3 The Function of b_dev, b_blocknr, and Request7.3.1 Ensure the Correctness of the Data Interaction between Processes and Buffer Block7.3.2 Let the Data Stay in the Buffer as Long as Possible7.4 Function of Uptodate and Dirt7.4.1 Function of b_uptodate7.4.2 Function of the b_dirt7.4.3 Function of the i_update, i_dirt, and s_dirt7.5 Function of the Count, Lock, Wait, Request7.5.1 Function of b_count7.5.2 Function of i_count7.5.3 Function of b_lock and *b_wait7.5.4 Function of i_lock, i_wait, s_lock, and *s_wait7.5.5 Function of Request7.6 Example 1: Process Waiting Queue of Buffer Block7.7 Overall Look at the Buffer Block and the Request Item