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Make vm_object_page_clean() and vm_mmap_vnode() tolerate the vnode'

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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
This commit is contained in:
Konstantin Belousov 2013-04-28 19:25:09 +00:00
parent 9b8851faae
commit e5f299ff76
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=250029
2 changed files with 15 additions and 3 deletions
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11
sys/vm/vm_mmap.c
View file

@ -1284,7 +1284,7 @@ vm_mmap_vnode(struct thread *td, vm_size_t objsize,
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_t objsize,
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;

7
sys/vm/vm_object.c
View file

@ -820,7 +820,12 @@ vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
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);