diff -urN 2.4.7pre4/fs/buffer.c bh_async/fs/buffer.c
--- 2.4.7pre4/fs/buffer.c	Tue Jul 10 00:03:05 2001
+++ bh_async/fs/buffer.c	Tue Jul 10 03:48:10 2001
@@ -823,10 +823,11 @@
 	 * that unlock the page..
 	 */
 	spin_lock_irqsave(&page_uptodate_lock, flags);
+	mark_buffer_async(bh, 0);
 	__unlock_buffer(bh);
 	tmp = bh->b_this_page;
 	while (tmp != bh) {
-		if (tmp->b_end_io == end_buffer_io_async && buffer_locked(tmp))
+		if (buffer_async(tmp) && buffer_locked(tmp))
 			goto still_busy;
 		tmp = tmp->b_this_page;
 	}
@@ -858,8 +859,9 @@
 	return;
 }
 
-void set_buffer_async_io(struct buffer_head *bh) {
+inline void set_buffer_async_io(struct buffer_head *bh) {
     bh->b_end_io = end_buffer_io_async ;
+    mark_buffer_async(bh, 1);
 }
 
 /*
@@ -1549,7 +1551,7 @@
 	/* Stage 2: lock the buffers, mark them clean */
 	do {
 		lock_buffer(bh);
-		bh->b_end_io = end_buffer_io_async;
+		set_buffer_async_io(bh);
 		get_bh(bh);
 		set_bit(BH_Uptodate, &bh->b_state);
 		clear_bit(BH_Dirty, &bh->b_state);
@@ -1751,7 +1753,7 @@
 	for (i = 0; i < nr; i++) {
 		struct buffer_head * bh = arr[i];
 		lock_buffer(bh);
-		bh->b_end_io = end_buffer_io_async;
+		set_buffer_async_io(bh);
 		get_bh(bh);
 	}
 
@@ -2198,7 +2200,7 @@
 		lock_buffer(bh);
 		bh->b_blocknr = *(b++);
 		set_bit(BH_Mapped, &bh->b_state);
-		bh->b_end_io = end_buffer_io_async;
+		set_buffer_async_io(bh);
 		get_bh(bh);
 		bh = bh->b_this_page;
 	} while (bh != head);
diff -urN 2.4.7pre4/include/linux/fs.h bh_async/include/linux/fs.h
--- 2.4.7pre4/include/linux/fs.h	Mon Jul  9 20:25:17 2001
+++ bh_async/include/linux/fs.h	Tue Jul 10 03:46:27 2001
@@ -215,6 +215,7 @@
 	BH_Mapped,	/* 1 if the buffer has a disk mapping */
 	BH_New,		/* 1 if the buffer is new and not yet written out */
 	BH_Protected,	/* 1 if the buffer is protected */
+	BH_Async,	/* 1 if the buffer is under end_buffer_io_async I/O */
 
 	BH_PrivateStart,/* not a state bit, but the first bit available
 			 * for private allocation by other entities
@@ -275,6 +276,7 @@
 #define buffer_mapped(bh)	__buffer_state(bh,Mapped)
 #define buffer_new(bh)		__buffer_state(bh,New)
 #define buffer_protected(bh)	__buffer_state(bh,Protected)
+#define buffer_async(bh)	__buffer_state(bh,Async)
 
 #define bh_offset(bh)		((unsigned long)(bh)->b_data & ~PAGE_MASK)
 
@@ -1109,6 +1111,14 @@
 extern void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));
 
 #define atomic_set_buffer_dirty(bh) test_and_set_bit(BH_Dirty, &(bh)->b_state)
+
+static inline void mark_buffer_async(struct buffer_head * bh, int on)
+{
+	if (on)
+		set_bit(BH_Async, &bh->b_state);
+	else
+		clear_bit(BH_Async, &bh->b_state);
+}
 
 /*
  * If an error happens during the make_request, this function