Introduce and use sleeplocks instead of BUSY flags

Remove I_BUSY, B_BUSY, and intrans defs and usages
One spinlock per buf to avoid ugly loop in bget
fix race in filewrite (don't update f->off after releasing lock)

1 files changed, 6 insertions, 1 deletions

diff --git a/spinlock.h b/spinlock.h
index fdda016..f6a69b7 100644
--- a/spinlock.h
+++ b/spinlock.h
@@ -1,4 +1,4 @@
-// Mutual exclusion lock.
+// Mutual exclusion lock for short code fragments
 struct spinlock {
   uint locked;       // Is the lock held?
   
@@ -9,3 +9,8 @@ struct spinlock {
                      // that locked the lock.
 };
 
+// Lock that maybe held across sleeps
+struct sleeplock {
+  uint locked;       // Is the lock held?
+};
+