Illumos 4901 - zfs filesystem/snapshot limit leaks

4901 zfs filesystem/snapshot limit leaks
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/4901
  illumos/illumos-gate@adf3407

Ported by: Brian Behlendorf <behlendorf1@llnl.gov>

Author: jjelinek

module/zfs/dsl_dir.c

@@ -512,7 +512,7 @@ dsl_dir_init_fs_ss_count(dsl_dir_t *dd, dmu_tx_t *tx)
 	zap_attribute_t *za;
 	dsl_dataset_t *ds;
 
-	ASSERT(spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT));
+	ASSERT(spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT));
 	ASSERT(dsl_pool_config_held(dp));
 	ASSERT(dmu_tx_is_syncing(tx));
 
@@ -1751,7 +1751,7 @@ dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
 	}
 
 	if (dmu_tx_is_syncing(tx)) {
-		if (spa_feature_is_enabled(dp->dp_spa,
+		if (spa_feature_is_active(dp->dp_spa,
 		    SPA_FEATURE_FS_SS_LIMIT)) {
 			/*
 			 * Although this is the check function and we don't
@@ -1780,8 +1780,11 @@ dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
 			err = zap_lookup(os, dd->dd_object,
 			    DD_FIELD_FILESYSTEM_COUNT, sizeof (fs_cnt), 1,
 			    &fs_cnt);
-			if (err != ENOENT && err != 0)
+			if (err != ENOENT && err != 0) {
+				dsl_dir_rele(newparent, FTAG);
+				dsl_dir_rele(dd, FTAG);
 				return (err);
+			}
 
 			/*
 			 * have to add 1 for the filesystem itself that we're
@@ -1792,8 +1795,11 @@ dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
 			err = zap_lookup(os, dd->dd_object,
 			    DD_FIELD_SNAPSHOT_COUNT, sizeof (ss_cnt), 1,
 			    &ss_cnt);
-			if (err != ENOENT && err != 0)
+			if (err != ENOENT && err != 0) {
+				dsl_dir_rele(newparent, FTAG);
+				dsl_dir_rele(dd, FTAG);
 				return (err);
+			}
 		}
 
 		/* no rename into our descendant */
@@ -1844,7 +1850,7 @@ dsl_dir_rename_sync(void *arg, dmu_tx_t *tx)
 		 * We already made sure the dd counts were initialized in the
 		 * check function.
 		 */
-		if (spa_feature_is_enabled(dp->dp_spa,
+		if (spa_feature_is_active(dp->dp_spa,
 		    SPA_FEATURE_FS_SS_LIMIT)) {
 			VERIFY0(zap_lookup(os, dd->dd_object,
 			    DD_FIELD_FILESYSTEM_COUNT, sizeof (fs_cnt), 1,