Changes from John Dyson and myself:

Fixed remaining known bugs in the buffer IO and VM system.

vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).

(various)
Replaced calls to clrbuf() with calls to an optimized routine
called vfs_bio_clrbuf().

(various FS sync)
Sync out modified vnode_pager backed pages.

ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.

vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.

vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().

vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.

vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.

1 files changed, 20 insertions, 3 deletions

diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index df5e4c4..9e04ee1 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -66,7 +66,7 @@
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
  *
- * $Id: vm_fault.c,v 1.20 1995/03/01 23:29:55 davidg Exp $
+ * $Id: vm_fault.c,v 1.21 1995/03/27 02:41:00 davidg Exp $
  */
 
 /*
@@ -94,6 +94,10 @@ int vm_fault_additional_pages __P((vm_object_t, vm_offset_t, vm_page_t, int, int
 extern int swap_pager_full;
 extern int vm_pageout_proc_limit;
 
+struct vnode *vnode_pager_lock __P((vm_object_t object));
+void vnode_pager_unlock __P((struct vnode *));
+
+
 /*
  *	vm_fault:
  *
@@ -137,6 +141,7 @@ vm_fault(map, vaddr, fault_type, change_wiring)
 	vm_page_t marray[VM_FAULT_READ];
 	int spl;
 	int hardfault = 0;
+	struct vnode *vp = NULL;
 
 	cnt.v_vm_faults++;	/* needs lock XXX */
 /*
@@ -173,6 +178,7 @@ vm_fault(map, vaddr, fault_type, change_wiring)
 		vm_object_unlock(first_object);		\
 	}						\
 	UNLOCK_MAP;					\
+	if (vp != NULL) vnode_pager_unlock(vp);		\
 }
 
 #define	UNLOCK_AND_DEALLOCATE	{			\
@@ -192,6 +198,9 @@ RetryFault:;
 	    &first_offset, &prot, &wired, &su)) != KERN_SUCCESS) {
 		return (result);
 	}
+
+	vp = (struct vnode *) vnode_pager_lock(first_object);
+
 	lookup_still_valid = TRUE;
 
 	if (wired)
@@ -271,6 +280,7 @@ RetryFault:;
 				vm_object_deallocate(first_object);
 				goto RetryFault;
 			}
+
 			if ((m->flags & PG_CACHE) &&
 			    (cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_reserved) {
 				UNLOCK_AND_DEALLOCATE;
@@ -364,8 +374,13 @@ readrest:
 				 * if moved.
 				 */
 				m = vm_page_lookup(object, offset);
-				m->valid = VM_PAGE_BITS_ALL;
+				if( !m) {
+					UNLOCK_AND_DEALLOCATE;
+					goto RetryFault;
+				}
+					
 				pmap_clear_modify(VM_PAGE_TO_PHYS(m));
+				m->valid = VM_PAGE_BITS_ALL;
 				hardfault++;
 				break;
 			}
@@ -808,6 +823,7 @@ RetryCopy:
 
 	if (prot & VM_PROT_WRITE) {
 		m->flags |= PG_WRITEABLE;
+		m->object->flags |= OBJ_WRITEABLE;
 		/*
 		 * If the fault is a write, we know that this page is being
 		 * written NOW. This will save on the pmap_is_modified() calls
@@ -817,11 +833,12 @@ RetryCopy:
 			m->dirty = VM_PAGE_BITS_ALL;
 		}
 	}
+
 	m->flags |= PG_MAPPED;
 
 	pmap_enter(map->pmap, vaddr, VM_PAGE_TO_PHYS(m), prot, wired);
 #if 0
-	if( ((prot & VM_PROT_WRITE) == 0) && change_wiring == 0 && wired == 0)
+	if (change_wiring == 0 && wired == 0)
 		pmap_prefault(map->pmap, vaddr, entry, first_object);
 #endif