Initial Upload

buf.h

@@ -0,0 +1,14 @@
+struct buf {
+    int flags;
+    uint dev;
+    uint blockno;
+    struct sleeplock lock;
+    uint refcnt;
+    struct buf *prev; // LRU cache list
+    struct buf *next;
+    struct buf *qnext; // disk queue
+    uchar data[BSIZE];
+};
+#define B_VALID 0x2  // buffer has been read from disk
+#define B_DIRTY 0x4  // buffer needs to be written to disk
+