predictive prefetch disabled on new pools until export/reboot

When a pool is initially created (by `zpool create`), predictive
prefetch is inadvertently disabled, until the pool is export/import-ed,
or the machine is rebooted.

When device removal was introduced, we added some code to disable
predictive prefetching until indirect vdevs have been loaded.  This
resulted in the "default state" of prefetch being disabled, until we
proactively enable it after indirect vdevs are loaded.  Unfortunately
this resulted in a few bugs where in some code paths we neglect to
enable predictive prefetch.  The first of these was fixed by
https://github.com/zfsonlinux/zfs/commit/20507534d4ede14d4dd82c99fc8d461704ce7419

This commit fixes another case where we also need to explicitly enable
predictive prefetch, when the pool is initially created.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8577

diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 5392e35478704cbdff0f40cf0d7a2af92aba317d..3857d0183b60139ba1b950e07a8992479e3fc9cc 100644 (file)
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
  * Copyright (c) 2018, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  * Copyright 2013 Saso Kiselkov. All rights reserved.
@@ -5183,6 +5183,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
        spa->spa_removing_phys.sr_state = DSS_NONE;
        spa->spa_removing_phys.sr_removing_vdev = -1;
        spa->spa_removing_phys.sr_prev_indirect_vdev = -1;
+       spa->spa_indirect_vdevs_loaded = B_TRUE;
 
        /*
         * Create "The Godfather" zio to hold all async IOs