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/zfs_onexit.c

@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/types.h>
@@ -109,7 +110,7 @@ zfs_onexit_minor_to_state(minor_t minor, zfs_onexit_t **zo)
 {
 	*zo = zfsdev_get_state(minor, ZST_ONEXIT);
 	if (*zo == NULL)
-		return (EBADF);
+		return (SET_ERROR(EBADF));
 
 	return (0);
 }
@@ -128,7 +129,7 @@ zfs_onexit_fd_hold(int fd, minor_t *minorp)
 
 	fp = getf(fd);
 	if (fp == NULL)
-		return (EBADF);
+		return (SET_ERROR(EBADF));
 
 	*minorp = zfsdev_getminor(fp->f_file);
 	return (zfs_onexit_minor_to_state(*minorp, &zo));
@@ -211,7 +212,7 @@ zfs_onexit_del_cb(minor_t minor, uint64_t action_handle, boolean_t fire)
 		kmem_free(ap, sizeof (zfs_onexit_action_node_t));
 	} else {
 		mutex_exit(&zo->zo_lock);
-		error = ENOENT;
+		error = SET_ERROR(ENOENT);
 	}
 
 	return (error);
@@ -240,7 +241,7 @@ zfs_onexit_cb_data(minor_t minor, uint64_t action_handle, void **data)
 	if (ap != NULL)
 		*data = ap->za_data;
 	else
-		error = ENOENT;
+		error = SET_ERROR(ENOENT);
 	mutex_exit(&zo->zo_lock);
 
 	return (error);