Revert r253939:

We cannot busy a page before doing pagefaults.
Infact, it can deadlock against vnode lock, as it tries to vget().
Other functions, right now, have an opposite lock ordering, like
vm_object_sync(), which acquires the vnode lock first and then
sleeps on the busy mechanism.

Before this patch is reinserted we need to break this ordering.

Sponsored by:	EMC / Isilon storage division
Reported by:	kib

1 files changed, 8 insertions, 6 deletions

diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c
index 540eb7b41c7b..d867612a7bd2 100644
--- a/sys/fs/tmpfs/tmpfs_vnops.c
+++ b/sys/fs/tmpfs/tmpfs_vnops.c
@@ -485,13 +485,13 @@ tmpfs_nocacheread(vm_object_t tobj, vm_pindex_t idx,
 			vm_page_zero_invalid(m, TRUE);
 		vm_page_wakeup(m);
 	}
-	vm_page_io_start(m);
+	vm_page_lock(m);
+	vm_page_hold(m);
+	vm_page_unlock(m);
 	VM_OBJECT_WUNLOCK(tobj);
 	error = uiomove_fromphys(&m, offset, tlen, uio);
-	VM_OBJECT_WLOCK(tobj);
-	vm_page_io_finish(m);
-	VM_OBJECT_WUNLOCK(tobj);
 	vm_page_lock(m);
+	vm_page_unhold(m);
 	if (m->queue == PQ_NONE) {
 		vm_page_deactivate(m);
 	} else {
@@ -602,14 +602,16 @@ tmpfs_mappedwrite(vm_object_t tobj, size_t len, struct uio *uio)
 			vm_page_zero_invalid(tpg, TRUE);
 		vm_page_wakeup(tpg);
 	}
-	vm_page_io_start(tpg);
+	vm_page_lock(tpg);
+	vm_page_hold(tpg);
+	vm_page_unlock(tpg);
 	VM_OBJECT_WUNLOCK(tobj);
 	error = uiomove_fromphys(&tpg, offset, tlen, uio);
 	VM_OBJECT_WLOCK(tobj);
-	vm_page_io_finish(tpg);
 	if (error == 0)
 		vm_page_dirty(tpg);
 	vm_page_lock(tpg);
+	vm_page_unhold(tpg);
 	if (tpg->queue == PQ_NONE) {
 		vm_page_deactivate(tpg);
 	} else {