svn commit: r250029 - head/sys/vm

[Konstantin Belousov]

Author: kib
Date: Sun Apr 28 19:25:09 2013
New Revision: 250029
URL: http://svnweb.freebsd.org/changeset/base/250029

Log:
  Make vm_object_page_clean() and vm_mmap_vnode() tolerate the vnode'
  v_object of non OBJT_VNODE type.
  
  For vm_object_page_clean(), simply do not assert that object type must
  be OBJT_VNODE, and add a comment explaining how the check for
  OBJ_MIGHTBEDIRTY prevents the rest of function from operating on such
  objects.
  
  For vm_mmap_vnode(), if the object type is not OBJT_VNODE, require it
  to be for swap pager (or default), handle the bypass filesystems, and
  correctly acquire the object reference in this case.
  
  Reviewed by:	alc
  Tested by:	pho, bf
  MFC after:	1 week

Modified:
  head/sys/vm/vm_mmap.c
  head/sys/vm/vm_object.c

Modified: head/sys/vm/vm_mmap.c
==============================================================================
--- head/sys/vm/vm_mmap.c	Sun Apr 28 19:19:26 2013	(r250028)
+++ head/sys/vm/vm_mmap.c	Sun Apr 28 19:25:09 2013	(r250029)
@@ -1284,7 +1284,7 @@ vm_mmap_vnode(struct thread *td, vm_size
 			error = EINVAL;
 			goto done;
 		}
-		if (obj->handle != vp) {
+		if (obj->type == OBJT_VNODE && obj->handle != vp) {
 			vput(vp);
 			vp = (struct vnode *)obj->handle;
 			/*
@@ -1333,7 +1333,14 @@ vm_mmap_vnode(struct thread *td, vm_size
 	objsize = round_page(va.va_size);
 	if (va.va_nlink == 0)
 		flags |= MAP_NOSYNC;
-	obj = vm_pager_allocate(OBJT_VNODE, vp, objsize, prot, foff, cred);
+	if (obj->type == OBJT_VNODE)
+		obj = vm_pager_allocate(OBJT_VNODE, vp, objsize, prot, foff,
+		    cred);
+	else {
+		KASSERT(obj->type == OBJT_DEFAULT || obj->type == OBJT_SWAP,
+		    ("wrong object type"));
+		vm_object_reference(obj);
+	}
 	if (obj == NULL) {
 		error = ENOMEM;
 		goto done;

Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c	Sun Apr 28 19:19:26 2013	(r250028)
+++ head/sys/vm/vm_object.c	Sun Apr 28 19:25:09 2013	(r250029)
@@ -820,7 +820,12 @@ vm_object_page_clean(vm_object_t object,
 	boolean_t clearobjflags, eio, res;
 
 	VM_OBJECT_ASSERT_WLOCKED(object);
-	KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
+
+	/*
+	 * The OBJ_MIGHTBEDIRTY flag is only set for OBJT_VNODE
+	 * objects.  The check below prevents the function from
+	 * operating on non-vnode objects.
+	 */
 	if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
 	    object->resident_page_count == 0)
 		return (TRUE);