Sprinkle some assertions in the buffer code.

Add a new DEBUG function "buf_print" that prints the contents of struct buf.

2 files changed, 73 insertions, 5 deletions

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 97be296ac4d..27d8a10fd33 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_bio.c,v 1.45 2001/10/11 14:44:10 art Exp $	*/
+/*	$OpenBSD: vfs_bio.c,v 1.46 2001/10/28 00:42:43 art Exp $	*/
 /*	$NetBSD: vfs_bio.c,v 1.44 1996/06/11 11:15:36 pk Exp $	*/
 
 /*-
@@ -524,6 +524,8 @@ brelse(bp)
 	/* Block disk interrupts. */
 	s = splbio();
 
+	KASSERT(ISSET(bp->b_flags, B_BUSY));
+
 	/*
 	 * Determine which queue the buffer should be on, then put it there.
 	 */
@@ -757,6 +759,7 @@ allocbuf(bp, size)
 	if (bp->b_bufsize == desired_size)
 		goto out;
 
+	KASSERT(!ISSET(bp->b_flags, (B_CACHE|B_DONE|B_DELWRI)));
 	/*
 	 * If the buffer is smaller than the desired size, we need to snarf
 	 * it from other buffers.  Get buffers (via getnewbuf()), and
@@ -797,7 +800,7 @@ allocbuf(bp, size)
 	 */
 	if (bp->b_bufsize > desired_size) {
 		s = splbio();
-		if ((nbp = bufqueues[BQ_EMPTY].tqh_first) == NULL) {
+		if ((nbp = TAILQ_FIRST(&bufqueues[BQ_EMPTY])) == NULL) {
 			/* No free buffer head */
 			splx(s);
 			goto out;
@@ -873,6 +876,8 @@ start:
 
 	bremfree(bp);
 
+	KASSERT(!ISSET(bp->b_flags, B_BUSY));
+
 	/* Buffer is no longer on free lists. */
 	SET(bp->b_flags, B_BUSY);
 
@@ -1041,9 +1046,11 @@ biodone(bp)
 		CLR(bp->b_flags, B_CALL);	/* but note callout done */
 		(*bp->b_iodone)(bp);
 	} else {
-		if (ISSET(bp->b_flags, B_ASYNC)) {/* if async, release it */
+		if (ISSET(bp->b_flags, B_ASYNC)) {
+			/* if async, release it */
 			brelse(bp);
-		} else {			/* or just wakeup the buffer */
+		} else {
+			/* or just wakeup the buffer */
 			CLR(bp->b_flags, B_WANTED);
 			wakeup(bp);
 		}
@@ -1052,6 +1059,63 @@ biodone(bp)
 
 #ifdef DEBUG
 /*
+ * Print as much as possible about a buffer.
+ */
+void
+buf_print(struct buf *bp)
+{
+	int f = 1;
+
+#define FLAG(fl) if (bp->b_flags & (fl)) { if (!f) printf(", "); else f = 0; printf(#fl); }
+
+	printf("b_proc: %p\n",		bp->b_proc);
+	printf("b_error: %d\n",		bp->b_error);
+	printf("b_bufsize: %ld\n",	bp->b_bufsize);
+	printf("b_bcount: %ld\n",	bp->b_bcount);
+	printf("b_resid: %ld\n",	(long)bp->b_resid);
+	printf("b_dev: (%d,%d)\n",	minor(bp->b_dev), major(bp->b_dev));
+	printf("b_data: %p\n",		bp->b_data);
+	printf("b_blkno: %ld\n",	(long)bp->b_blkno);
+	printf("b_lblkno: %ld\n",	(long)bp->b_lblkno);
+
+	printf("b_flags: ");
+
+	FLAG(B_AGE);
+	FLAG(B_NEEDCOMMIT);
+	FLAG(B_ASYNC);
+	FLAG(B_BAD);
+	FLAG(B_BUSY);
+	FLAG(B_CACHE);
+	FLAG(B_CALL);
+	FLAG(B_DELWRI);
+	FLAG(B_DIRTY);
+	FLAG(B_DONE);
+	FLAG(B_EINTR);
+	FLAG(B_ERROR);
+	FLAG(B_GATHERED);
+	FLAG(B_INVAL);
+	FLAG(B_LOCKED);
+	FLAG(B_NOCACHE);
+	FLAG(B_PAGET);
+	FLAG(B_PGIN);
+	FLAG(B_PHYS);
+	FLAG(B_RAW);
+	FLAG(B_READ);
+	FLAG(B_TAPE);
+	FLAG(B_UAREA);
+	FLAG(B_WANTED);
+	FLAG(B_WRITE);	
+	FLAG(B_WRITEINPROG);
+	FLAG(B_XXX);
+	FLAG(B_DEFERRED);
+	FLAG(B_SCANNED);
+
+	printf("\n");
+
+#undef FLAG
+}
+
+/*
  * Print out statistics on the current allocation of the buffer pool.
  * Can be enabled to print out on every ``sync'' by setting "syncprt"
  * in vfs_syscalls.c using sysctl.
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
index f8f5cf70b0f..1894209a978 100644
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: buf.h,v 1.29 2001/09/20 08:22:26 gluk Exp $	*/
+/*	$OpenBSD: buf.h,v 1.30 2001/10/28 00:42:43 art Exp $	*/
 /*	$NetBSD: buf.h,v 1.25 1997/04/09 21:12:17 mycroft Exp $	*/
 
 /*
@@ -227,6 +227,10 @@ void  bgetvp __P((struct vnode *, struct buf *));
 void  buf_replacevnode __P((struct buf *, struct vnode *));
 void  buf_daemon __P((struct proc *));
 
+#ifdef DEBUG
+void buf_print(struct buf *);
+#endif
+
 static __inline void
 buf_start(struct buf *bp)
 {