OpenZFS 9280 - Assertion failure while running removal_with_ganging test with 4K devices

Authored by: Matt Ahrens <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: John Kennedy <[email protected]>
Reviewed-by: Giuseppe Di Natale <[email protected]>
Approved by: Garrett D'Amore <[email protected]>
Ported-by: Brian Behlendorf <[email protected]>

OpenZFS-issue: https://www.illumos.org/issues/9280
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/243952c
Closes #7445

4 files changed, 32 insertions, 18 deletions

diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 315169571..84e13c14a 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -168,7 +168,7 @@ typedef struct ztest_shared_opts {
 	int zo_init;
 	uint64_t zo_time;
 	uint64_t zo_maxloops;
-	uint64_t zo_metaslab_gang_bang;
+	uint64_t zo_metaslab_force_ganging;
 	int zo_mmp_test;
 } ztest_shared_opts_t;
 
@@ -192,10 +192,10 @@ static const ztest_shared_opts_t ztest_opts_defaults = {
 	.zo_init = 1,
 	.zo_time = 300,			/* 5 minutes */
 	.zo_maxloops = 50,		/* max loops during spa_freeze() */
-	.zo_metaslab_gang_bang = 32 << 10
+	.zo_metaslab_force_ganging = 32 << 10
 };
 
-extern uint64_t metaslab_gang_bang;
+extern uint64_t metaslab_force_ganging;
 extern uint64_t metaslab_df_alloc_threshold;
 extern unsigned long zfs_deadman_synctime_ms;
 extern int metaslab_preload_limit;
@@ -635,12 +635,12 @@ usage(boolean_t requested)
 	const ztest_shared_opts_t *zo = &ztest_opts_defaults;
 
 	char nice_vdev_size[NN_NUMBUF_SZ];
-	char nice_gang_bang[NN_NUMBUF_SZ];
+	char nice_force_ganging[NN_NUMBUF_SZ];
 	FILE *fp = requested ? stdout : stderr;
 
 	nicenum(zo->zo_vdev_size, nice_vdev_size, sizeof (nice_vdev_size));
-	nicenum(zo->zo_metaslab_gang_bang, nice_gang_bang,
-	    sizeof (nice_gang_bang));
+	nicenum(zo->zo_metaslab_force_ganging, nice_force_ganging,
+	    sizeof (nice_force_ganging));
 
 	(void) fprintf(fp, "Usage: %s\n"
 	    "\t[-v vdevs (default: %llu)]\n"
@@ -677,7 +677,7 @@ usage(boolean_t requested)
 	    zo->zo_raidz_parity,			/* -R */
 	    zo->zo_datasets,				/* -d */
 	    zo->zo_threads,				/* -t */
-	    nice_gang_bang,				/* -g */
+	    nice_force_ganging,				/* -g */
 	    zo->zo_init,				/* -i */
 	    (u_longlong_t)zo->zo_killrate,		/* -k */
 	    zo->zo_pool,				/* -p */
@@ -746,8 +746,8 @@ process_options(int argc, char **argv)
 			zo->zo_threads = MAX(1, value);
 			break;
 		case 'g':
-			zo->zo_metaslab_gang_bang = MAX(SPA_MINBLOCKSIZE << 1,
-			    value);
+			zo->zo_metaslab_force_ganging =
+			    MAX(SPA_MINBLOCKSIZE << 1, value);
 			break;
 		case 'i':
 			zo->zo_init = value;
@@ -7299,7 +7299,7 @@ main(int argc, char **argv)
 	zs = ztest_shared;
 
 	if (fd_data_str) {
-		metaslab_gang_bang = ztest_opts.zo_metaslab_gang_bang;
+		metaslab_force_ganging = ztest_opts.zo_metaslab_force_ganging;
 		metaslab_df_alloc_threshold =
 		    zs->zs_metaslab_df_alloc_threshold;
 
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5
index 8b007ea17..75fd5808b 100644
--- a/man/man5/zfs-module-parameters.5
+++ b/man/man5/zfs-module-parameters.5
@@ -223,6 +223,18 @@ Use \fB1\fR for yes (default) and \fB0\fR for no.
 .sp
 .ne 2
 .na
+\fBmetaslab_force_ganging\fR (ulong)
+.ad
+.RS 12n
+Make some blocks above a certain size be gang blocks.  This option is used
+by the test suite to facilitate testing.
+.sp
+Default value: \fB16,777,217\fR.
+.RE
+
+.sp
+.ne 2
+.na
 \fBzfs_metaslab_segment_weight_enabled\fR (int)
 .ad
 .RS 12n
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 52a60cc5e..ae98c5143 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -48,8 +48,10 @@
  */
 unsigned long metaslab_aliquot = 512 << 10;
 
-/* force gang blocks */
-unsigned long metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1;
+/*
+ * For testing, make some blocks above a certain size be gang blocks.
+ */
+unsigned long metaslab_force_ganging = SPA_MAXBLOCKSIZE + 1;
 
 /*
  * The in-core space map representation is more compact than its on-disk form.
@@ -2952,7 +2954,7 @@ metaslab_alloc_dva(spa_t *spa, metaslab_class_t *mc, uint64_t psize,
 	/*
 	 * For testing, make some blocks above a certain size be gang blocks.
 	 */
-	if (psize >= metaslab_gang_bang && (ddi_get_lbolt() & 3) == 0) {
+	if (psize >= metaslab_force_ganging && (ddi_get_lbolt() & 3) == 0) {
 		metaslab_trace_add(zal, NULL, NULL, psize, d, TRACE_FORCE_GANG);
 		return (SET_ERROR(ENOSPC));
 	}
@@ -3900,7 +3902,7 @@ MODULE_PARM_DESC(zfs_metaslab_switch_threshold,
 	"segment-based metaslab selection maximum buckets before switching");
 
 /* CSTYLED */
-module_param(metaslab_gang_bang, ulong, 0644);
-MODULE_PARM_DESC(metaslab_gang_bang,
+module_param(metaslab_force_ganging, ulong, 0644);
+MODULE_PARM_DESC(metaslab_force_ganging,
 	"blocks larger than this size are forced to be gang blocks");
 #endif /* _KERNEL && HAVE_SPL */
diff --git a/tests/zfs-tests/tests/functional/removal/removal_with_ganging.ksh b/tests/zfs-tests/tests/functional/removal/removal_with_ganging.ksh
index cfbca89bd..0cb22e3e1 100755
--- a/tests/zfs-tests/tests/functional/removal/removal_with_ganging.ksh
+++ b/tests/zfs-tests/tests/functional/removal/removal_with_ganging.ksh
@@ -15,7 +15,7 @@
 #
 
 #
-# Copyright (c) 2014, 2016 by Delphix. All rights reserved.
+# Copyright (c) 2014, 2017 by Delphix. All rights reserved.
 #
 
 . $STF_SUITE/include/libtest.shlib
@@ -23,12 +23,12 @@
 
 function cleanup
 {
-	log_must set_tunable64 metaslab_gang_bang $((2**17 + 1))
+	log_must set_tunable64 metaslab_force_ganging $((2**17 + 1))
 	default_cleanup_noexit
 }
 
 default_setup_noexit "$DISKS"
-log_must set_tunable64 metaslab_gang_bang $((2**12))
+log_must set_tunable64 metaslab_force_ganging $((2**14))
 log_onexit cleanup
 
 FILE_CONTENTS="Leeloo Dallas mul-ti-pass."