Illumos #3598

3598 want to dtrace when errors are generated in zfs
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

References:
  https://www.illumos.org/issues/3598
  illumos/illumos-gate@be6fd75a69

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting notes:

1. include/sys/zfs_context.h has been modified to render some new
   macros inert until dtrace is available on Linux.

2. Linux-specific changes have been adapted to use SET_ERROR().

3. I'm NOT happy about this change.  It does nothing but ugly
   up the code under Linux.  Unfortunately we need to take it to
   avoid more merge conflicts in the future.  -Brian

module/zfs/spa_history.c

@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/spa.h>
@@ -309,7 +309,7 @@ spa_history_log_nvl(spa_t *spa, nvlist_t *nvl)
 	nvlist_t *nvarg;
 
 	if (spa_version(spa) < SPA_VERSION_ZPOOL_HISTORY || !spa_writeable(spa))
-		return (EINVAL);
+		return (SET_ERROR(EINVAL));
 
 	tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
 	err = dmu_tx_assign(tx, TXG_WAIT);
@@ -353,7 +353,7 @@ spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf)
 	 * that's ok, just return ENOENT.
 	 */
 	if (!spa->spa_history)
-		return (ENOENT);
+		return (SET_ERROR(ENOENT));
 
 	/*
 	 * The history is logged asynchronously, so when they request