Skip import activity test in more zdb code paths

Since zdb opens the pools read-only, it cannot damage the pool in the
event the pool is already imported either on the same host or on
another one.

If the pool vdev structure is changing while zdb is importing the
pool, it may cause zdb to crash.  However this is unlikely, and in any
case it's a user space process and can simply be run again.

For this reason, zdb should disable the multihost activity test on
import that is normally run.

This commit fixes a few zdb code paths where that had been overlooked.
It also adds tests to ensure that several common use cases handle this
properly in the future.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Gu Zheng <[email protected]>
Signed-off-by: Olaf Faaland <[email protected]>
Closes #7797 
Closes #7801 

1 files changed, 26 insertions, 16 deletions

diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 142968d07..38ffbbece 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -24,7 +24,7 @@
  * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2016 Nexenta Systems, Inc.
- * Copyright (c) 2017 Lawrence Livermore National Security, LLC.
+ * Copyright (c) 2017, 2018 Lawrence Livermore National Security, LLC.
  * Copyright (c) 2015, 2017, Intel Corporation.
  */
 
@@ -4558,6 +4558,22 @@ verify_device_removal_feature_counts(spa_t *spa)
 	return (ret);
 }
 
+static void
+zdb_set_skip_mmp(char *target)
+{
+	spa_t *spa;
+
+	/*
+	 * Disable the activity check to allow examination of
+	 * active pools.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	if ((spa = spa_lookup(target)) != NULL) {
+		spa->spa_import_flags |= ZFS_IMPORT_SKIP_MMP;
+	}
+	mutex_exit(&spa_namespace_lock);
+}
+
 #define	BOGUS_SUFFIX "_CHECKPOINTED_UNIVERSE"
 /*
  * Import the checkpointed state of the pool specified by the target
@@ -4592,6 +4608,7 @@ import_checkpointed_state(char *target, nvlist_t *cfg, char **new_path)
 	}
 
 	if (cfg == NULL) {
+		zdb_set_skip_mmp(poolname);
 		error = spa_get_stats(poolname, &cfg, NULL, 0);
 		if (error != 0) {
 			fatal("Tried to read config of pool \"%s\" but "
@@ -4605,7 +4622,8 @@ import_checkpointed_state(char *target, nvlist_t *cfg, char **new_path)
 	fnvlist_add_string(cfg, ZPOOL_CONFIG_POOL_NAME, bogus_name);
 
 	error = spa_import(bogus_name, cfg, NULL,
-	    ZFS_IMPORT_MISSING_LOG | ZFS_IMPORT_CHECKPOINT);
+	    ZFS_IMPORT_MISSING_LOG | ZFS_IMPORT_CHECKPOINT |
+	    ZFS_IMPORT_SKIP_MMP);
 	if (error != 0) {
 		fatal("Tried to import pool \"%s\" but spa_import() failed "
 		    "with error %d\n", bogus_name, error);
@@ -5739,15 +5757,15 @@ main(int argc, char **argv)
 				    target, strerror(ENOMEM));
 			}
 
-			/*
-			 * Disable the activity check to allow examination of
-			 * active pools.
-			 */
 			if (dump_opt['C'] > 1) {
 				(void) printf("\nConfiguration for import:\n");
 				dump_nvlist(cfg, 8);
 			}
 
+			/*
+			 * Disable the activity check to allow examination of
+			 * active pools.
+			 */
 			error = spa_import(target_pool, cfg, NULL,
 			    flags | ZFS_IMPORT_SKIP_MMP);
 		}
@@ -5769,16 +5787,7 @@ main(int argc, char **argv)
 			}
 
 		} else if (target_is_spa || dump_opt['R']) {
-			/*
-			 * Disable the activity check to allow examination of
-			 * active pools.
-			 */
-			mutex_enter(&spa_namespace_lock);
-			if ((spa = spa_lookup(target)) != NULL) {
-				spa->spa_import_flags |= ZFS_IMPORT_SKIP_MMP;
-			}
-			mutex_exit(&spa_namespace_lock);
-
+			zdb_set_skip_mmp(target);
 			error = spa_open_rewind(target, &spa, FTAG, policy,
 			    NULL);
 			if (error) {
@@ -5801,6 +5810,7 @@ main(int argc, char **argv)
 				}
 			}
 		} else {
+			zdb_set_skip_mmp(target);
 			error = open_objset(target, DMU_OST_ANY, FTAG, &os);
 			if (error == 0)
 				spa = dmu_objset_spa(os);