ZFS Import All protection

Import all now checks for pool health before attempting an import.
Pools that have been destroyed or are not healthy are not considered
for import. Such pools can still be imported individually.

ZFSWrapper/ZFSUtils.cpp

@@ -772,7 +772,8 @@ namespace zfs
 		return pools;
 	}
 
-	static std::vector<ZPool> import_with_args(libzfs_handle_t * handle, importargs_t * args)
+	static std::vector<ZPool> import_with_args(libzfs_handle_t * handle, importargs_t * args,
+											   bool allowUnhealthy)
 	{
 		thread_init();
 		auto list = NVList(zpool_search_import(handle, args), zfs::NVList::TakeOwnership());
@@ -781,6 +782,14 @@ namespace zfs
 		for (auto pair : list)
 		{
 			auto l = pair.convertTo<NVList>();
+			uint64_t poolState = l.lookup<uint64_t>(ZPOOL_CONFIG_POOL_STATE);
+			if (poolState == POOL_STATE_DESTROYED)
+				continue; // Ignore destroyed pools
+			char * msg = nullptr;
+			zpool_errata_t errata = {};
+			zpool_status_t status = zpool_import_status(l.toList(), &msg, &errata);
+			if (!allowUnhealthy && !healthy(status))
+				continue; // Ignore pools that aren't healthy
 			auto r = zpool_import(handle, l.toList(), nullptr, nullptr);
 			if (r == 0)
 			{
@@ -797,14 +806,14 @@ namespace zfs
 	std::vector<ZPool> LibZFSHandle::importAllPools() const
 	{
 		importargs_t args = {};
-		return import_with_args(handle(), &args);
+		return import_with_args(handle(), &args, false);
 	}
 
 	ZPool LibZFSHandle::import(std::string const & name) const
 	{
 		importargs_t args = {};
 		args.poolname = const_cast<char*>(name.c_str());
-		auto pools = import_with_args(handle(), &args);
+		auto pools = import_with_args(handle(), &args, true);
 		if (pools.size() != 1)
 			throw std::runtime_error("Invalid number of pools imported");
 		return std::move(pools.front());
@@ -814,7 +823,7 @@ namespace zfs
 	{
 		importargs_t args = {};
 		args.guid = guid;
-		auto pools = import_with_args(handle(), &args);
+		auto pools = import_with_args(handle(), &args, true);
 		if (pools.size() != 1)
 			throw std::runtime_error("Invalid number of pools imported");
 		return std::move(pools.front());