OpenZFS 7280 - Allow changing global libzpool variables in zdb and ztest through command line

Authored by: Pavel Zakharov <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Dan Kimmel <[email protected]>
Approved by: Robert Mustacchi <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Ported-by: George Melikov <[email protected]>

OpenZFS-issue: https://www.illumos.org/issues/7280
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0e60744
Closes #5676 

2 files changed, 20 insertions, 6 deletions

diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 6a36aa1ef..10bca4a91 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -127,7 +127,8 @@ usage(void)
 {
 	(void) fprintf(stderr,
 	    "Usage: %s [-CumMdibcsDvhLXFPAG] [-t txg] [-e [-p path...]] "
-	    "[-U config] [-I inflight I/Os] [-x dumpdir] poolname [object...]\n"
+	    "[-U config] [-I inflight I/Os] [-x dumpdir] [-o var=value] "
+	    "poolname [object...]\n"
 	    "       %s [-divPA] [-e -p path...] [-U config] dataset "
 	    "[object...]\n"
 	    "       %s -mM [-LXFPA] [-t txg] [-e [-p path...]] [-U config] "
@@ -189,6 +190,8 @@ usage(void)
 	    "checksumming I/Os [default is 200]\n");
 	(void) fprintf(stderr, "        -G dump zfs_dbgmsg buffer before "
 	    "exiting\n");
+	(void) fprintf(stderr, "        -o <variable>=<value> set global "
+	    "variable to an unsigned 32-bit integer value\n");
 	(void) fprintf(stderr, "Specify an option more than once (e.g. -bb) "
 	    "to make only that option verbose\n");
 	(void) fprintf(stderr, "Default is to dump everything non-verbosely\n");
@@ -3707,7 +3710,7 @@ main(int argc, char **argv)
 		spa_config_path = spa_config_path_env;
 
 	while ((c = getopt(argc, argv,
-	    "bcdhilmMI:suCDRSAFLXx:evp:t:U:PVG")) != -1) {
+	    "bcdhilmMI:suCDRSAFLXx:evp:t:U:PVGo")) != -1) {
 		switch (c) {
 		case 'b':
 		case 'c':
@@ -3762,9 +3765,6 @@ main(int argc, char **argv)
 			}
 			searchdirs[nsearch++] = optarg;
 			break;
-		case 'x':
-			vn_dumpdir = optarg;
-			break;
 		case 't':
 			max_txg = strtoull(optarg, NULL, 0);
 			if (max_txg < TXG_INITIAL) {
@@ -3779,6 +3779,14 @@ main(int argc, char **argv)
 		case 'v':
 			verbose++;
 			break;
+		case 'x':
+			vn_dumpdir = optarg;
+			break;
+		case 'o':
+			error = set_global_var(optarg);
+			if (error != 0)
+				usage();
+			break;
 		default:
 			usage();
 			break;
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 70a3e206f..d1c6a783a 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -629,6 +629,8 @@ usage(boolean_t requested)
 	    "\t[-F freezeloops (default: %llu)] max loops in spa_freeze()\n"
 	    "\t[-P passtime (default: %llu sec)] time per pass\n"
 	    "\t[-B alt_ztest (default: <none>)] alternate ztest path\n"
+	    "\t[-o variable=value] ... set global variable to an unsigned\n"
+	    "\t    32-bit integer value\n"
 	    "\t[-h] (print help)\n"
 	    "",
 	    zo->zo_pool,
@@ -664,7 +666,7 @@ process_options(int argc, char **argv)
 	bcopy(&ztest_opts_defaults, zo, sizeof (*zo));
 
 	while ((opt = getopt(argc, argv,
-	    "v:s:a:m:r:R:d:t:g:i:k:p:f:VET:P:hF:B:")) != EOF) {
+	    "v:s:a:m:r:R:d:t:g:i:k:p:f:VET:P:hF:B:o:")) != EOF) {
 		value = 0;
 		switch (opt) {
 		case 'v':
@@ -752,6 +754,10 @@ process_options(int argc, char **argv)
 		case 'B':
 			(void) strlcpy(altdir, optarg, sizeof (altdir));
 			break;
+		case 'o':
+			if (set_global_var(optarg) != 0)
+				usage(B_FALSE);
+			break;
 		case 'h':
 			usage(B_TRUE);
 			break;