--- xfstest/linux/include/linux/elevator.h	Wed Feb 14 16:55:55 2001
+++ 2.4xfs-pure/linux/include/linux/elevator.h	Tue Feb  6 19:32:56 2001
@@ -8,7 +8,8 @@
 			    struct list_head *, int);
 
 typedef int (elevator_merge_fn) (request_queue_t *, struct request **, struct list_head *,
-				 struct buffer_head *, int, int, int);
+				 struct buffer_head *, int, int, int, struct kiobuf *,
+                                 kdev_t, unsigned int);
 
 typedef void (elevator_merge_cleanup_fn) (request_queue_t *, struct request *, int);
 
@@ -26,11 +27,11 @@
 	unsigned int queue_ID;
 };
 
-int elevator_noop_merge(request_queue_t *, struct request **, struct list_head *, struct buffer_head *, int, int, int);
+int elevator_noop_merge(request_queue_t *, struct request **, struct list_head *, struct buffer_head *, int, int, int, struct kiobuf *, kdev_t, unsigned int);
 void elevator_noop_merge_cleanup(request_queue_t *, struct request *, int);
 void elevator_noop_merge_req(struct request *, struct request *);
 
-int elevator_linus_merge(request_queue_t *, struct request **, struct list_head *, struct buffer_head *, int, int, int);
+int elevator_linus_merge(request_queue_t *, struct request **, struct list_head *, struct buffer_head *, int, int, int, struct kiobuf *, kdev_t, unsigned int);
 void elevator_linus_merge_cleanup(request_queue_t *, struct request *, int);
 void elevator_linus_merge_req(struct request *, struct request *);
 
--- xfstest/linux/drivers/block/elevator.c	Wed Feb 14 16:54:14 2001
+++ 2.4xfs-pure/linux/drivers/block/elevator.c	Tue Feb  6 19:32:14 2001
@@ -30,11 +30,17 @@
 int elevator_linus_merge(request_queue_t *q, struct request **req,
 			 struct list_head * head,
 			 struct buffer_head *bh, int rw,
-			 int max_sectors, int max_segments)
+			 int max_sectors, int max_segments,
+                         struct kiobuf * kiobuf, kdev_t dev,
+                         unsigned int kendsector)
 {
 	struct list_head *entry = &q->queue_head;
-	unsigned int count = bh->b_size >> 9, ret = ELEVATOR_NO_MERGE;
+	unsigned int count, ret = ELEVATOR_NO_MERGE;
+        unsigned int tmpdist, currdist = INT_MAX;
 
+        if (bh) 
+                count = bh->b_size >> 9;
+        
 	while ((entry = entry->prev) != head) {
 		struct request *__rq = blkdev_entry_to_request(entry);
 
@@ -45,32 +51,38 @@
 			*req = __rq;
 			break;
 		}
-
-		if (__rq->kiobuf)
-			continue;
-		if (__rq->sem)
-			continue;
-		if (__rq->cmd != rw)
-			continue;
-		if (__rq->rq_dev != bh->b_rdev)
-			continue;
-		if (__rq->nr_sectors + count > max_sectors)
-			continue;
-		if (__rq->elevator_sequence < count)
-			break;
-		if (__rq->sector + __rq->nr_sectors == bh->b_rsector) {
-			ret = ELEVATOR_BACK_MERGE;
-			*req = __rq;
-			break;
-		} else if (__rq->sector - count == bh->b_rsector) {
-			ret = ELEVATOR_FRONT_MERGE;
-			__rq->elevator_sequence -= count;
-			*req = __rq;
-			break;
-		} else if (!*req && BHRQ_IN_ORDER(bh, __rq))
-			*req = __rq;
-	}
-
+                if (bh) {
+                        if (__rq->sem)
+                                continue;
+                        if (__rq->cmd != rw)
+                                continue;
+                        if (__rq->rq_dev != bh->b_rdev)
+                                continue;
+                        if (__rq->nr_sectors + count > max_sectors)
+                                continue;
+                        if (__rq->elevator_sequence < count)
+                                break;
+                        if (__rq->bh && __rq->sector + __rq->nr_sectors == bh->b_rsector) {
+                                ret = ELEVATOR_BACK_MERGE;
+                                *req = __rq;
+                                break;
+                        } else if (__rq->bh && __rq->sector - count == bh->b_rsector) {
+                                ret = ELEVATOR_FRONT_MERGE;
+                                __rq->elevator_sequence -= count;
+                                *req = __rq;
+                                break;
+                        } else if (!*req && BHRQ_IN_ORDER(bh, __rq)) {
+                                *req = __rq;
+                        } 
+                } else if (dev == __rq->rq_dev && kendsector < __rq->sector) {
+                        tmpdist = __rq->sector - kendsector;
+                        if (tmpdist < currdist) {
+                                *req = __rq;
+                                currdist = tmpdist;
+                        }
+                }
+        }
+        
 	return ret;
 }
 
@@ -99,7 +111,9 @@
 int elevator_noop_merge(request_queue_t *q, struct request **req,
 			struct list_head * head,
 			struct buffer_head *bh, int rw,
-			int max_sectors, int max_segments)
+			int max_sectors, int max_segments,
+                        struct kiobuf * kiobuf, kdev_t dev,
+                        unsigned int kendsector)
 {
 	struct list_head *entry;
 	unsigned int count = bh->b_size >> 9;
--- xfstest/linux/drivers/block/ll_rw_blk.c	Wed Feb 14 16:54:14 2001
+++ 2.4xfs-pure/linux/drivers/block/ll_rw_blk.c	Wed Feb  7 16:31:20 2001
@@ -952,11 +952,9 @@
 	} else if (q->head_active && !q->plugged)
 		head = head->next;
 
-	if (kiobuf)
-                goto get_rq;
-
 	el_ret = elevator->elevator_merge_fn(q, &req, head, bh, rw,
-					     max_sectors, max_segments);
+					     max_sectors, max_segments,
+                                             kiobuf, dev, sector+count);
 	switch (el_ret) {
 
 		case ELEVATOR_BACK_MERGE:
@@ -1401,14 +1399,24 @@
 		goto end_io;
 	}
 
+        /*
+         * don't initiate I/O if we're already above the high
+         * water mark. instead start I/O on the queued stuff.
+         */
+        if (atomic_read(&queued_sectors) >= high_queued_sectors) {
+                run_task_queue(&tq_disk);
+                wait_event(blk_buffers_wait,
+                           atomic_read(&queued_sectors) < low_queued_sectors);
+        }
+        
 	switch(rw) {
 	case WRITE:
-		kstat.pgpgout++;
+		kstat.pgpgout += (kiobuf->length >> 9);
 		break;
 
 	case READA:
 	case READ:
-		kstat.pgpgin++;
+		kstat.pgpgin += (kiobuf->length >> 9);
 		break;
 	default:
 		BUG();