From 5eab7e540605a77b6d141deee5fbaf56291be23a Mon Sep 17 00:00:00 2001
From: Steven Hartland <smh@FreeBSD.org>
Date: Sun, 18 Jan 2015 23:15:49 +0000
Subject: [PATCH] Clean ZFS spa config before syncing

A number of entries that can be present in the spa config shouldn't be saved
to disk so add a method to ensure this is case. Without this if the last
caller to vdev_config_generate requested stats then we can end up in the
cache file.

Also only skip a none writable pool in the cache file generation if its
active. This prevents unavailable pools incorrectly getting removed from
cache file.

Tested by:	delphij
MFC after:	2 weeks
Sponsored by:	Multiplay
---
 .../uts/common/fs/zfs/spa_config.c            | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
index c4ee741e9a7..be1e528f7f4 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
@@ -140,6 +140,26 @@ out:
 	kobj_close_file(file);
 }
 
+static void
+spa_config_clean(nvlist_t *nvl)
+{
+	nvlist_t **child;
+	nvlist_t *nvroot = NULL;
+	uint_t c, children;
+
+	if (nvlist_lookup_nvlist_array(nvl, ZPOOL_CONFIG_CHILDREN, &child,
+	    &children) == 0) {
+		for (c = 0; c < children; c++)
+			spa_config_clean(child[c]);
+	}
+
+	if (nvlist_lookup_nvlist(nvl, ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0)
+		spa_config_clean(nvroot);
+
+	nvlist_remove(nvl, ZPOOL_CONFIG_VDEV_STATS, DATA_TYPE_UINT64_ARRAY);
+	nvlist_remove(nvl, ZPOOL_CONFIG_SCAN_STATS, DATA_TYPE_UINT64_ARRAY);
+}
+
 static int
 spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
 {
@@ -233,6 +253,7 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
 		 */
 		nvl = NULL;
 		while ((spa = spa_next(spa)) != NULL) {
+			nvlist_t *nvroot = NULL;
 			/*
 			 * Skip over our own pool if we're about to remove
 			 * ourselves from the spa namespace or any pool that
@@ -241,7 +262,8 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
 			 * we don't allow them to be written to the cache file.
 			 */
 			if ((spa == target && removing) ||
-			    !spa_writeable(spa))
+			    (spa_state(spa) == POOL_STATE_ACTIVE &&
+			    !spa_writeable(spa)))
 				continue;
 
 			mutex_enter(&spa->spa_props_lock);
@@ -260,6 +282,9 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
 			VERIFY(nvlist_add_nvlist(nvl, spa->spa_name,
 			    spa->spa_config) == 0);
 			mutex_exit(&spa->spa_props_lock);
+
+			if (nvlist_lookup_nvlist(nvl, spa->spa_name, &nvroot) == 0)
+				spa_config_clean(nvroot);
 		}
 
 		error = spa_config_write(dp, nvl);