Function dnode_evict_dbufs

freebsd/contrib/openzfs/module/zfs/dnode_sync.c:455–509

* Try to kick all the dnode's dbufs out of the cache... */

 * Try to kick all the dnode's dbufs out of the cache...
 */
void
dnode_evict_dbufs(dnode_t *dn)
{
	dmu_buf_impl_t *db_marker;
	dmu_buf_impl_t *db, *db_next;

	db_marker = kmem_alloc(sizeof (dmu_buf_impl_t), KM_SLEEP);

	mutex_enter(&dn->dn_dbufs_mtx);
	for (db = avl_first(&dn->dn_dbufs); db != NULL; db = db_next) {

#ifdef	ZFS_DEBUG
		DB_DNODE_ENTER(db);
		ASSERT3P(DB_DNODE(db), ==, dn);
		DB_DNODE_EXIT(db);
#endif	/* DEBUG */

		mutex_enter(&db->db_mtx);
		if (db->db_state != DB_EVICTING &&
		    zfs_refcount_is_zero(&db->db_holds)) {
			db_marker->db_level = db->db_level;
			db_marker->db_blkid = db->db_blkid;
			db_marker->db_state = DB_SEARCH;
			avl_insert_here(&dn->dn_dbufs, db_marker, db,
			    AVL_BEFORE);

			/*
			 * We need to use the "marker" dbuf rather than
			 * simply getting the next dbuf, because
			 * dbuf_destroy() may actually remove multiple dbufs.
			 * It can call itself recursively on the parent dbuf,
			 * which may also be removed from dn_dbufs.  The code
			 * flow would look like:
			 *
			 * dbuf_destroy():
			 *   dnode_rele_and_unlock(parent_dbuf, evicting=TRUE):
			 *	if (!cacheable || pending_evict)
			 *	  dbuf_destroy()
			 */
			dbuf_destroy(db);

			db_next = AVL_NEXT(&dn->dn_dbufs, db_marker);
			avl_remove(&dn->dn_dbufs, db_marker);
		} else {
			db->db_pending_evict = TRUE;
			mutex_exit(&db->db_mtx);
			db_next = AVL_NEXT(&dn->dn_dbufs, db);
		}
	}
	mutex_exit(&dn->dn_dbufs_mtx);

	kmem_free(db_marker, sizeof (dmu_buf_impl_t));

	dnode_evict_bonus(dn);
}

void
dnode_evict_bonus(dnode_t *dn)