From 0bc63d83f62374f688366caed69946a93e29f57d Mon Sep 17 00:00:00 2001
From: George Melikov <mail@gmelikov.ru>
Date: Thu, 12 Jan 2017 22:58:04 +0300
Subject: [PATCH] OpenZFS 6603 - zfeature_register() should verify
 ZFEATURE_FLAG_PER_DATASET implies SPA_FEATURE_EXTENSIBLE_DATASET

Authored by: ilovezfs <ilovezfs@icloud.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>

OpenZFS-issue: https://www.illumos.org/issues/6603
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0803e91
Closes #5573
---
 module/zfs/zfeature_common.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/module/zfs/zfeature_common.c b/module/zfs/zfeature_common.c
index 0459d45219..06e15bfd3c 100644
--- a/module/zfs/zfeature_common.c
+++ b/module/zfs/zfeature_common.c
@@ -134,6 +134,18 @@ zfeature_depends_on(spa_feature_t fid, spa_feature_t check)
 	return (B_FALSE);
 }
 
+static boolean_t
+deps_contains_feature(const spa_feature_t *deps, const spa_feature_t feature)
+{
+	int i;
+
+	for (i = 0; deps[i] != SPA_FEATURE_NONE; i++)
+		if (deps[i] == feature)
+			return (B_TRUE);
+
+	return (B_FALSE);
+}
+
 static void
 zfeature_register(spa_feature_t fid, const char *guid, const char *name,
     const char *desc, zfeature_flags_t flags, const spa_feature_t *deps)
@@ -151,6 +163,9 @@ zfeature_register(spa_feature_t fid, const char *guid, const char *name,
 	if (deps == NULL)
 		deps = nodeps;
 
+	VERIFY(((flags & ZFEATURE_FLAG_PER_DATASET) == 0) ||
+	    (deps_contains_feature(deps, SPA_FEATURE_EXTENSIBLE_DATASET)));
+
 	feature->fi_feature = fid;
 	feature->fi_guid = guid;
 	feature->fi_uname = name;