Revert "Introduce and use sleeplocks instead of BUSY flags"

My changes have a race with re-used bufs and the code doesn't seem to get shorter
Keep the changes that fixed ip->off race

This reverts commit 3a5fa7ed9020eaf8ab843a16d26db7393b2ec072.

Conflicts:

	defs.h
	file.c
	file.h

1 files changed, 3 insertions, 4 deletions

diff --git a/buf.h b/buf.h
index cfeb8c6..9c586f2 100644
--- a/buf.h
+++ b/buf.h
@@ -2,13 +2,12 @@ struct buf {
   int flags;
   uint dev;
   uint sector;
-  struct spinlock lock;
-  struct sleeplock sleeplock;
   struct buf *prev; // LRU cache list
   struct buf *next;
   struct buf *qnext; // disk queue
   uchar data[512];
 };
-#define B_VALID 0x1  // buffer has been read from disk
-#define B_DIRTY 0x2  // buffer needs to be written to disk
+#define B_BUSY  0x1  // buffer is locked by some process
+#define B_VALID 0x2  // buffer has been read from disk
+#define B_DIRTY 0x4  // buffer needs to be written to disk