Revert "zhack: Add 'feature disable' command"

This reverts commit 8302528617 and
ebecfcd699 which broke the build.
While these patches do apply cleanly and passed previous test
runs they need to be updated to account for the changes made in
commit 241b541574.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #3878

cmd/zhack/zhack.c

@@ -58,13 +58,12 @@ libzfs_handle_t *g_zfs;
 static importargs_t g_importargs;
 static char *g_pool;
 static boolean_t g_readonly;
-static boolean_t g_force = B_FALSE;
 
 static void
 usage(void)
 {
 	(void) fprintf(stderr,
-	    "Usage: %s [-c cachefile] [-d dir] [-f] <subcommand> <args> ...\n"
+	    "Usage: %s [-c cachefile] [-d dir] <subcommand> <args> ...\n"
 	    "where <subcommand> <args> is one of the following:\n"
 	    "\n", cmdname);
 
@@ -74,9 +73,6 @@ usage(void)
 	    "    feature enable [-d desc] <pool> <feature>\n"
 	    "        add a new enabled feature to the pool\n"
 	    "        -d <desc> sets the feature's description\n"
-	    "    feature disable <pool> <feature>\n"
-	    "        remove an enabled, but not active, feature\n"
-	    "        from the pool.\n"
 	    "    feature ref [-md] <pool> <feature>\n"
 	    "        change the refcount on the given feature\n"
 	    "        -d decrease instead of increase the refcount\n"
@@ -357,10 +353,8 @@ zhack_do_feature_enable(int argc, char **argv)
 	zhack_spa_open(target, B_FALSE, FTAG, &spa);
 	mos = spa->spa_meta_objset;
 
-	if (zfeature_is_supported(feature.fi_guid) && (g_force == B_FALSE))
+	if (zfeature_is_supported(feature.fi_guid))
-		fatal(spa, FTAG,
+		fatal(spa, FTAG, "'%s' is a real feature, will not enable");
-		    "'%s' is a real feature, will not enable\n"
-		    "provide the -f option to force override", feature.fi_guid);
 	if (0 == zap_contains(mos, spa->spa_feat_desc_obj, feature.fi_guid))
 		fatal(spa, FTAG, "feature already enabled: %s",
 		    feature.fi_guid);
@@ -373,94 +367,6 @@ zhack_do_feature_enable(int argc, char **argv)
 	free(desc);
 }
 
-static void
-zhack_feature_disable_sync(void *arg, dmu_tx_t *tx)
-{
-	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
-	zfeature_info_t *feature = arg;
-
-	feature_disable_sync(spa, feature, tx);
-
-	spa_history_log_internal(spa, "zhack disable feature", tx,
-	    "name=%s can_readonly=%u",
-	    feature->fi_guid, feature->fi_can_readonly);
-}
-
-static void
-zhack_do_feature_disable(int argc, char **argv)
-{
-	char c;
-	char *target;
-	uint64_t count;
-	spa_t *spa;
-	objset_t *mos;
-	zfeature_info_t feature;
-	spa_feature_t nodeps[] = { SPA_FEATURE_NONE };
-
-	/*
-	 * fi_desc does not matter here because it was written to disk
-	 * when the feature was enabled, but we need to properly set the
-	 * feature for read or write based on the information we read off
-	 * disk later.
-	 */
-	feature.fi_uname = "zhack";
-	feature.fi_mos = B_TRUE;
-	feature.fi_desc = NULL;
-	feature.fi_depends = nodeps;
-	feature.fi_feature = SPA_FEATURE_NONE;
-
-	optind = 1;
-	while ((c = getopt(argc, argv, "")) != -1) {
-		switch (c) {
-		default:
-			usage();
-			break;
-		}
-	}
-	argc -= optind;
-	argv += optind;
-
-	if (argc < 2) {
-		(void) fprintf(stderr, "error: missing feature or pool name\n");
-		usage();
-	}
-	target = argv[0];
-	feature.fi_guid = argv[1];
-
-	if (!zfeature_is_valid_guid(feature.fi_guid))
-		fatal(NULL, FTAG, "invalid feature guid: %s", feature.fi_guid);
-
-	zhack_spa_open(target, B_FALSE, FTAG, &spa);
-	mos = spa->spa_meta_objset;
-
-	if (zfeature_is_supported(feature.fi_guid) && (g_force == B_FALSE)) {
-		fatal(spa, FTAG,
-		    "'%s' is a real feature, will not disable\n"
-		    "provide the -f option to force override", feature.fi_guid);
-	}
-
-	if (0 == zap_contains(mos, spa->spa_feat_for_read_obj,
-	    feature.fi_guid)) {
-		feature.fi_can_readonly = B_FALSE;
-	} else if (0 == zap_contains(mos, spa->spa_feat_for_write_obj,
-	    feature.fi_guid)) {
-		feature.fi_can_readonly = B_TRUE;
-	} else {
-		fatal(spa, FTAG, "feature is not enabled: %s", feature.fi_guid);
-	}
-
-	if (feature_get_refcount_from_disk(spa, &feature, &count) == 0 &&
-	    count > 0) {
-		fatal(spa, FTAG, "feature '%s' is active, can not disable",
-		    feature.fi_guid);
-	}
-
-	VERIFY0(dsl_sync_task(spa_name(spa), NULL,
-	    zhack_feature_disable_sync, &feature, 5, ZFS_SPACE_CHECK_NORMAL));
-
-	spa_close(spa, FTAG);
-}
-
 static void
 feature_incr_sync(void *arg, dmu_tx_t *tx)
 {
@@ -589,8 +495,6 @@ zhack_do_feature(int argc, char **argv)
 		zhack_do_feature_stat(argc, argv);
 	} else if (strcmp(subcommand, "enable") == 0) {
 		zhack_do_feature_enable(argc, argv);
-	} else if (strcmp(subcommand, "disable") == 0) {
-		zhack_do_feature_disable(argc, argv);
 	} else if (strcmp(subcommand, "ref") == 0) {
 		zhack_do_feature_ref(argc, argv);
 	} else {
@@ -619,7 +523,7 @@ main(int argc, char **argv)
 	dprintf_setup(&argc, argv);
 	zfs_prop_init();
 
-	while ((c = getopt(argc, argv, "c:d:f")) != -1) {
+	while ((c = getopt(argc, argv, "c:d:")) != -1) {
 		switch (c) {
 		case 'c':
 			g_importargs.cachefile = optarg;
@@ -628,9 +532,6 @@ main(int argc, char **argv)
 			assert(g_importargs.paths < MAX_NUM_PATHS);
 			g_importargs.path[g_importargs.paths++] = optarg;
 			break;
-		case 'f':
-			g_force = B_TRUE;
-			break;
 		default:
 			usage();
 			break;

include/sys/zfeature.h

@@ -63,8 +63,6 @@ extern int feature_get_refcount_from_disk(spa_t *spa, zfeature_info_t *feature,
     uint64_t *res);
 extern void feature_enable_sync(struct spa *, zfeature_info_t *,
     struct dmu_tx *);
-extern void feature_disable_sync(struct spa *, zfeature_info_t *,
-    struct dmu_tx *);
 extern void feature_sync(struct spa *, zfeature_info_t *, uint64_t,
     struct dmu_tx *);
 

lib/libzpool/kernel.c

@@ -647,6 +647,8 @@ vn_open(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2, int x3)
 #ifdef __linux__
 		flags |= O_DIRECT;
 #endif
+		/* We shouldn't be writing to block devices in userspace */
+		VERIFY(!(flags & FWRITE));
 	}
 
 	if (flags & FCREAT)

module/zfs/zfeature.c

@@ -380,43 +380,6 @@ feature_enable_sync(spa_t *spa, zfeature_info_t *feature, dmu_tx_t *tx)
 	}
 }
 
-/*
- * This function is non-static for zhack; it should otherwise not be used
- * outside this file.
- */
-void
-feature_disable_sync(spa_t *spa, zfeature_info_t *feature, dmu_tx_t *tx)
-{
-	uint64_t descobj = spa->spa_feat_desc_obj;
-	uint64_t zapobj = feature->fi_can_readonly ?
-	    spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
-
-	ASSERT(0 != zapobj);
-	ASSERT(zfeature_is_valid_guid(feature->fi_guid));
-	ASSERT3U(spa_version(spa), >=, SPA_VERSION_FEATURES);
-
-	if (zap_contains(spa->spa_meta_objset, descobj, feature->fi_guid) == 0)
-		VERIFY0(zap_remove(spa->spa_meta_objset, descobj,
-		    feature->fi_guid, tx));
-
-	if (zap_contains(spa->spa_meta_objset, zapobj, feature->fi_guid) == 0)
-		VERIFY0(zap_remove(spa->spa_meta_objset, zapobj,
-		    feature->fi_guid, tx));
-
-	spa_deactivate_mos_feature(spa, feature->fi_guid);
-
-	if (spa_feature_is_enabled(spa, SPA_FEATURE_ENABLED_TXG)) {
-		uint64_t txgobj = spa->spa_feat_enabled_txg_obj;
-
-		if (txgobj && (zap_contains(spa->spa_meta_objset,
-		    txgobj, feature->fi_guid) == 0)) {
-			spa_feature_decr(spa, SPA_FEATURE_ENABLED_TXG, tx);
-			VERIFY0(zap_remove(spa->spa_meta_objset, txgobj,
-			    feature->fi_guid, tx));
-		}
-	}
-}
-
 static void
 feature_do_action(spa_t *spa, spa_feature_t fid, feature_action_t action,
     dmu_tx_t *tx)