1 files changed, 4 insertions, 1 deletions
diff --git a/buf.h b/buf.h
index ccf7f8b..ddc42c7 100644
--- a/buf.h
+++ b/buf.h
@@ -2,9 +2,12 @@ struct buf {
   int flags;
   uint dev;
   uint sector;
-  struct buf *prev;
+  struct buf *prev; // LRU cache list
   struct buf *next;
+  struct buf *qnext; // disk queue
+  int done;
   uchar data[512];
 };
 #define B_BUSY 0x1  // buffer is locked by some process
 #define B_VALID 0x2 // buffer contains the data of the sector
+#define B_WRITE 0x4 // asking device driver to write, else read