Avoid byte-swap cache corruption in libdb2

Apply a patch from NetBSD to restore the cached copy of a page to the
machine byte order after a write operation swapped it to the file byte
order.  As a regression test, modify test13 to sync the database file
after each put to exercise this bug.

ticket: 8483 (new)
target_version: 1.14-next
target_version: 1.13-next
tags: pullup

src/plugins/kdb/db2/libdb2/mpool/mpool.c

@@ -432,6 +432,14 @@ mpool_write(mp, bp)
 	if (write(mp->fd, bp->page, mp->pagesize) != mp->pagesize)
 		return (RET_ERROR);
 
+	/*
+	 * Re-run through the input filter since this page may soon be
+	 * accessed via the cache, and whatever the user's output filter
+	 * did may screw things up if we don't let the input filter
+	 * restore the in-core copy.
+	 */
+	if (mp->pgin)
+		(mp->pgin)(mp->pgcookie, bp->pgno, bp->page);
 	bp->flags &= ~MPOOL_DIRTY;
 	return (RET_SUCCESS);
 }

src/plugins/kdb/db2/libdb2/test/run.test

@@ -614,6 +614,7 @@ test13()
 				echo p
 				echo k$i
 				echo d$i
+				echo S
 				echo g
 				echo k$i
 			done > $TMP2