MFC r280238

Fix the root cause of the "vm_reserv_populate: reserv <address> is already
  promoted" panics.

PR:		198163

sys/vm/vm_fault.c

@@ -101,6 +101,7 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_kern.h>
 #include <vm/vm_pager.h>
 #include <vm/vm_extern.h>
+#include <vm/vm_reserv.h>
 
 #define PFBAK 4
 #define PFFOR 4
@@ -844,6 +845,14 @@ vnode_locked:
 					unlock_and_deallocate(&fs);
 					goto RetryFault;
 				}
+#if VM_NRESERVLEVEL > 0
+				/*
+				 * Rename the reservation.
+				 */
+				vm_reserv_rename(fs.m, fs.first_object,
+				    fs.object, OFF_TO_IDX(
+				    fs.first_object->backing_object_offset));
+#endif
 				vm_page_xbusy(fs.m);
 				fs.first_m = fs.m;
 				fs.m = NULL;