It's unlocking parent directory vnode because LOCKPARENT is *not* requested. Also fix a typo for "explicitly".
Index: sys/tmpfs/tmpfs_vnops.c =================================================================== RCS file: /cvs/src/sys/tmpfs/tmpfs_vnops.c,v retrieving revision 1.27 diff -u -p -r1.27 tmpfs_vnops.c --- sys/tmpfs/tmpfs_vnops.c 19 Jun 2016 11:54:33 -0000 1.27 +++ sys/tmpfs/tmpfs_vnops.c 20 Mar 2018 19:07:48 -0000 @@ -289,7 +289,7 @@ done: out: /* * If (1) we succeded, (2) found a distinct vnode to return and (3) were - * either explicitely told to keep the parent locked or are in the + * either explicitly told not to keep the parent locked or are in the * middle of a lookup, unlock the parent vnode. */ if ((error == 0 || error == EJUSTRETURN) && /* (1) */
