/*
* Flush all vnodes for which the pagedaemon has requested pageouts.
* Skip over any files that are marked VU_DIROP (since lfs_flush_dirop()
* has just run, this would be an error). If we have to skip a vnode
* for any reason, just skip it; if we have to wait for the cleaner,
* abort. The writer daemon will call us again later.
*/