Illumos 5959 - clean up per-dataset feature count code

5959 clean up per-dataset feature count code
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: George Wilson <george@delphix.com>
Reviewed by: Alex Reece <alex@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

References:
  https://www.illumos.org/issues/5959
  https://github.com/illumos/illumos-gate/commit/ca0cc39

Porting notes:

illumos code doesn't check for feature_get_refcount() returning
ENOTSUP (which means feature is disabled) in zdb. zfsonlinux added
a check in https://github.com/zfsonlinux/zfs/commit/784652c
due to #3468. The check was reintroduced here.

Ported-by: Witaut Bajaryn <vitaut.bayaryn@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3965

module/zfs/dbuf.c

@@ -1615,6 +1615,11 @@ dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
 	struct dirty_leaf *dl;
 	dmu_object_type_t type;
 
+	if (etype == BP_EMBEDDED_TYPE_DATA) {
+		ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset),
+		    SPA_FEATURE_EMBEDDED_DATA));
+	}
+
 	DB_DNODE_ENTER(db);
 	type = DB_DNODE(db)->dn_type;
 	DB_DNODE_EXIT(db);

module/zfs/dmu_send.c

@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
@@ -611,7 +611,7 @@ dmu_send_impl(void *tag, dsl_pool_t *dp, dsl_dataset_t *ds,
 	}
 #endif
 
-	if (large_block_ok && ds->ds_large_blocks)
+	if (large_block_ok && ds->ds_feature_inuse[SPA_FEATURE_LARGE_BLOCKS])
 		featureflags |= DMU_BACKUP_FEATURE_LARGE_BLOCKS;
 	if (embedok &&
 	    spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMBEDDED_DATA)) {
@@ -1226,13 +1226,6 @@ dmu_recv_begin_sync(void *arg, dmu_tx_t *tx)
 	}
 	VERIFY0(dsl_dataset_own_obj(dp, dsobj, dmu_recv_tag, &newds));
 
-	if ((DMU_GET_FEATUREFLAGS(drrb->drr_versioninfo) &
-	    DMU_BACKUP_FEATURE_LARGE_BLOCKS) &&
-	    !newds->ds_large_blocks) {
-		dsl_dataset_activate_large_blocks_sync_impl(dsobj, tx);
-		newds->ds_large_blocks = B_TRUE;
-	}
-
 	dmu_buf_will_dirty(newds->ds_dbuf, tx);
 	dsl_dataset_phys(newds)->ds_flags |= DS_FLAG_INCONSISTENT;
 

module/zfs/dsl_dataset.c

@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
  * Copyright (c) 2014 RackTop Systems.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
@@ -126,8 +126,10 @@ dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
 	dsl_dataset_phys(ds)->ds_compressed_bytes += compressed;
 	dsl_dataset_phys(ds)->ds_uncompressed_bytes += uncompressed;
 	dsl_dataset_phys(ds)->ds_unique_bytes += used;
-	if (BP_GET_LSIZE(bp) > SPA_OLD_MAXBLOCKSIZE)
-		ds->ds_need_large_blocks = B_TRUE;
+	if (BP_GET_LSIZE(bp) > SPA_OLD_MAXBLOCKSIZE) {
+		ds->ds_feature_activation_needed[SPA_FEATURE_LARGE_BLOCKS] =
+		    B_TRUE;
+	}
 	mutex_exit(&ds->ds_lock);
 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
 	    compressed, uncompressed, tx);
@@ -432,19 +434,25 @@ dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
 		    offsetof(dmu_sendarg_t, dsa_link));
 
 		if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
-			int zaperr = zap_contains(mos, dsobj,
-			    DS_FIELD_LARGE_BLOCKS);
-			if (zaperr != ENOENT) {
-				VERIFY0(zaperr);
-				ds->ds_large_blocks = B_TRUE;
+			spa_feature_t f;
+
+			for (f = 0; f < SPA_FEATURES; f++) {
+				if (!(spa_feature_table[f].fi_flags &
+				    ZFEATURE_FLAG_PER_DATASET))
+					continue;
+				err = zap_contains(mos, dsobj,
+				    spa_feature_table[f].fi_guid);
+				if (err == 0) {
+					ds->ds_feature_inuse[f] = B_TRUE;
+				} else {
+					ASSERT3U(err, ==, ENOENT);
+					err = 0;
+				}
 			}
 		}
 
-		if (err == 0) {
-			err = dsl_dir_hold_obj(dp,
-			    dsl_dataset_phys(ds)->ds_dir_obj, NULL, ds,
-			    &ds->ds_dir);
-		}
+		err = dsl_dir_hold_obj(dp,
+		    dsl_dataset_phys(ds)->ds_dir_obj, NULL, ds, &ds->ds_dir);
 		if (err != 0) {
 			mutex_destroy(&ds->ds_lock);
 			mutex_destroy(&ds->ds_opening_lock);
@@ -698,6 +706,34 @@ dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
 	return (gotit);
 }
 
+static void
+dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
+{
+	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
+	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
+	uint64_t zero = 0;
+
+	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
+
+	spa_feature_incr(spa, f, tx);
+	dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
+
+	VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
+	    sizeof (zero), 1, &zero, tx));
+}
+
+void
+dsl_dataset_deactivate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
+{
+	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
+	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
+
+	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
+
+	VERIFY0(zap_remove(mos, dsobj, spa_feature_table[f].fi_guid, tx));
+	spa_feature_decr(spa, f, tx);
+}
+
 uint64_t
 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
     uint64_t flags, dmu_tx_t *tx)
@@ -736,6 +772,7 @@ dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 	if (origin == NULL) {
 		dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
 	} else {
+		spa_feature_t f;
 		dsl_dataset_t *ohds; /* head of the origin snapshot */
 
 		dsphys->ds_prev_snap_obj = origin->ds_object;
@@ -756,8 +793,10 @@ dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 		dsphys->ds_flags |= dsl_dataset_phys(origin)->ds_flags &
 		    (DS_FLAG_INCONSISTENT | DS_FLAG_CI_DATASET);
 
-		if (origin->ds_large_blocks)
-			dsl_dataset_activate_large_blocks_sync_impl(dsobj, tx);
+		for (f = 0; f < SPA_FEATURES; f++) {
+			if (origin->ds_feature_inuse[f])
+				dsl_dataset_activate_feature(dsobj, f, tx);
+		}
 
 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
 		dsl_dataset_phys(origin)->ds_num_children++;
@@ -1233,6 +1272,7 @@ dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
 	dsl_dataset_phys_t *dsphys;
 	uint64_t dsobj, crtxg;
 	objset_t *mos = dp->dp_meta_objset;
+	spa_feature_t f;
 	ASSERTV(static zil_header_t zero_zil);
 	ASSERTV(objset_t *os);
 
@@ -1282,8 +1322,10 @@ dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
 	dsphys->ds_bp = dsl_dataset_phys(ds)->ds_bp;
 	dmu_buf_rele(dbuf, FTAG);
 
-	if (ds->ds_large_blocks)
-		dsl_dataset_activate_large_blocks_sync_impl(dsobj, tx);
+	for (f = 0; f < SPA_FEATURES; f++) {
+		if (ds->ds_feature_inuse[f])
+			dsl_dataset_activate_feature(dsobj, f, tx);
+	}
 
 	ASSERT3U(ds->ds_prev != 0, ==,
 	    dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
@@ -1561,6 +1603,8 @@ dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
 void
 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
 {
+	spa_feature_t f;
+
 	ASSERT(dmu_tx_is_syncing(tx));
 	ASSERT(ds->ds_objset != NULL);
 	ASSERT(dsl_dataset_phys(ds)->ds_next_snap_obj == 0);
@@ -1574,9 +1618,13 @@ dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
 
 	dmu_objset_sync(ds->ds_objset, zio, tx);
 
-	if (ds->ds_need_large_blocks && !ds->ds_large_blocks) {
-		dsl_dataset_activate_large_blocks_sync_impl(ds->ds_object, tx);
-		ds->ds_large_blocks = B_TRUE;
+	for (f = 0; f < SPA_FEATURES; f++) {
+		if (ds->ds_feature_activation_needed[f]) {
+			if (ds->ds_feature_inuse[f])
+				continue;
+			dsl_dataset_activate_feature(ds->ds_object, f, tx);
+			ds->ds_feature_inuse[f] = B_TRUE;
+		}
 	}
 }
 
@@ -2703,6 +2751,7 @@ void
 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
     dsl_dataset_t *origin_head, dmu_tx_t *tx)
 {
+	spa_feature_t f;
 	dsl_pool_t *dp = dmu_tx_pool(tx);
 	int64_t unused_refres_delta;
 
@@ -2711,6 +2760,43 @@ dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
 	    dsl_dataset_phys(clone)->ds_unique_bytes <= origin_head->ds_quota);
 	ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
 
+	/*
+	 * Swap per-dataset feature flags.
+	 */
+	for (f = 0; f < SPA_FEATURES; f++) {
+		boolean_t clone_inuse;
+		boolean_t origin_head_inuse;
+
+		if (!(spa_feature_table[f].fi_flags &
+		    ZFEATURE_FLAG_PER_DATASET)) {
+			ASSERT(!clone->ds_feature_inuse[f]);
+			ASSERT(!origin_head->ds_feature_inuse[f]);
+			continue;
+		}
+
+		clone_inuse = clone->ds_feature_inuse[f];
+		origin_head_inuse = origin_head->ds_feature_inuse[f];
+
+		if (clone_inuse) {
+			dsl_dataset_deactivate_feature(clone->ds_object, f, tx);
+			clone->ds_feature_inuse[f] = B_FALSE;
+		}
+		if (origin_head_inuse) {
+			dsl_dataset_deactivate_feature(origin_head->ds_object,
+			    f, tx);
+			origin_head->ds_feature_inuse[f] = B_FALSE;
+		}
+		if (clone_inuse) {
+			dsl_dataset_activate_feature(origin_head->ds_object,
+			    f, tx);
+			origin_head->ds_feature_inuse[f] = B_TRUE;
+		}
+		if (origin_head_inuse) {
+			dsl_dataset_activate_feature(clone->ds_object, f, tx);
+			clone->ds_feature_inuse[f] = B_TRUE;
+		}
+	}
+
 	dmu_buf_will_dirty(clone->ds_dbuf, tx);
 	dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
 
@@ -3265,77 +3351,6 @@ dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
 	return (err);
 }
 
-static int
-dsl_dataset_activate_large_blocks_check(void *arg, dmu_tx_t *tx)
-{
-	const char *dsname = arg;
-	dsl_dataset_t *ds;
-	dsl_pool_t *dp = dmu_tx_pool(tx);
-	int error = 0;
-
-	if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS))
-		return (SET_ERROR(ENOTSUP));
-
-	ASSERT(spa_feature_is_enabled(dp->dp_spa,
-	    SPA_FEATURE_EXTENSIBLE_DATASET));
-
-	error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
-	if (error != 0)
-		return (error);
-
-	if (ds->ds_large_blocks)
-		error = EALREADY;
-	dsl_dataset_rele(ds, FTAG);
-
-	return (error);
-}
-
-void
-dsl_dataset_activate_large_blocks_sync_impl(uint64_t dsobj, dmu_tx_t *tx)
-{
-	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
-	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
-	uint64_t zero = 0;
-
-	spa_feature_incr(spa, SPA_FEATURE_LARGE_BLOCKS, tx);
-	dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
-
-	VERIFY0(zap_add(mos, dsobj, DS_FIELD_LARGE_BLOCKS,
-	    sizeof (zero), 1, &zero, tx));
-}
-
-static void
-dsl_dataset_activate_large_blocks_sync(void *arg, dmu_tx_t *tx)
-{
-	const char *dsname = arg;
-	dsl_dataset_t *ds;
-
-	VERIFY0(dsl_dataset_hold(dmu_tx_pool(tx), dsname, FTAG, &ds));
-
-	dsl_dataset_activate_large_blocks_sync_impl(ds->ds_object, tx);
-	ASSERT(!ds->ds_large_blocks);
-	ds->ds_large_blocks = B_TRUE;
-	dsl_dataset_rele(ds, FTAG);
-}
-
-int
-dsl_dataset_activate_large_blocks(const char *dsname)
-{
-	int error;
-
-	error = dsl_sync_task(dsname,
-	    dsl_dataset_activate_large_blocks_check,
-	    dsl_dataset_activate_large_blocks_sync, (void *)dsname,
-	    1, ZFS_SPACE_CHECK_RESERVED);
-
-	/*
-	 * EALREADY indicates that this dataset already supports large blocks.
-	 */
-	if (error == EALREADY)
-		error = 0;
-	return (error);
-}
-
 /*
  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
  * For example, they could both be snapshots of the same filesystem, and
@@ -3380,7 +3395,6 @@ dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier,
 	return (ret);
 }
 
-
 void
 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
 {

module/zfs/dsl_destroy.c

@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  * Copyright (c) 2013 by Joyent, Inc. All rights reserved.
  */
@@ -246,6 +246,7 @@ dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 #ifdef ZFS_DEBUG
 	int err;
 #endif
+	spa_feature_t f;
 	int after_branch_point = FALSE;
 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
 	objset_t *mos = dp->dp_meta_objset;
@@ -277,9 +278,11 @@ dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 
 	obj = ds->ds_object;
 
-	if (ds->ds_large_blocks) {
-		ASSERT0(zap_contains(mos, obj, DS_FIELD_LARGE_BLOCKS));
-		spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
+	for (f = 0; f < SPA_FEATURES; f++) {
+		if (ds->ds_feature_inuse[f]) {
+			dsl_dataset_deactivate_feature(obj, f, tx);
+			ds->ds_feature_inuse[f] = B_FALSE;
+		}
 	}
 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 		ASSERT3P(ds->ds_prev, ==, NULL);
@@ -715,6 +718,7 @@ void
 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 {
 	dsl_pool_t *dp = dmu_tx_pool(tx);
+	spa_feature_t f;
 	objset_t *mos = dp->dp_meta_objset;
 	uint64_t obj, ddobj, prevobj = 0;
 	boolean_t rmorigin;
@@ -742,13 +746,17 @@ dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 		ASSERT0(ds->ds_reserved);
 	}
 
-	if (ds->ds_large_blocks)
-		spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
+	obj = ds->ds_object;
+
+	for (f = 0; f < SPA_FEATURES; f++) {
+		if (ds->ds_feature_inuse[f]) {
+			dsl_dataset_deactivate_feature(obj, f, tx);
+			ds->ds_feature_inuse[f] = B_FALSE;
+		}
+	}
 
 	dsl_scan_ds_destroyed(ds, tx);
 
-	obj = ds->ds_object;
-
 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 		/* This is a clone */
 		ASSERT(ds->ds_prev != NULL);

module/zfs/zfeature.c

@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -253,7 +253,7 @@ feature_get_refcount_from_disk(spa_t *spa, zfeature_info_t *feature,
 {
 	int err;
 	uint64_t refcount;
-	uint64_t zapobj = feature->fi_can_readonly ?
+	uint64_t zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
 	    spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
 
 	/*
@@ -306,7 +306,7 @@ feature_sync(spa_t *spa, zfeature_info_t *feature, uint64_t refcount,
 	uint64_t zapobj;
 
 	ASSERT(VALID_FEATURE_OR_NONE(feature->fi_feature));
-	zapobj = feature->fi_can_readonly ?
+	zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
 	    spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
 	VERIFY0(zap_update(spa->spa_meta_objset, zapobj, feature->fi_guid,
 	    sizeof (uint64_t), 1, &refcount, tx));
@@ -327,7 +327,7 @@ feature_sync(spa_t *spa, zfeature_info_t *feature, uint64_t refcount,
 
 	if (refcount == 0)
 		spa_deactivate_mos_feature(spa, feature->fi_guid);
-	else if (feature->fi_mos)
+	else if (feature->fi_flags & ZFEATURE_FLAG_MOS)
 		spa_activate_mos_feature(spa, feature->fi_guid, tx);
 }
 
@@ -338,8 +338,9 @@ feature_sync(spa_t *spa, zfeature_info_t *feature, uint64_t refcount,
 void
 feature_enable_sync(spa_t *spa, zfeature_info_t *feature, dmu_tx_t *tx)
 {
-	uint64_t initial_refcount = feature->fi_activate_on_enable ? 1 : 0;
-	uint64_t zapobj = feature->fi_can_readonly ?
+	uint64_t initial_refcount =
+	    (feature->fi_flags & ZFEATURE_FLAG_ACTIVATE_ON_ENABLE) ? 1 : 0;
+	uint64_t zapobj = (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
 	    spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj;
 	int i;
 
@@ -385,7 +386,8 @@ feature_do_action(spa_t *spa, spa_feature_t fid, feature_action_t action,
 {
 	uint64_t refcount = 0;
 	zfeature_info_t *feature = &spa_feature_table[fid];
-	ASSERTV(uint64_t zapobj = feature->fi_can_readonly ?
+	ASSERTV(uint64_t zapobj =
+	    (feature->fi_flags & ZFEATURE_FLAG_READONLY_COMPAT) ?
 	    spa->spa_feat_for_write_obj : spa->spa_feat_for_read_obj);
 
 	ASSERT(VALID_FEATURE_FID(fid));

module/zfs/zfeature_common.c

@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  * Copyright (c) 2014, Nexenta Systems, Inc. All rights reserved.
  */
@@ -135,15 +135,15 @@ zfeature_depends_on(spa_feature_t fid, spa_feature_t check) {
 
 static void
 zfeature_register(spa_feature_t fid, const char *guid, const char *name,
-    const char *desc, boolean_t readonly, boolean_t mos,
-    boolean_t activate_on_enable, const spa_feature_t *deps)
+    const char *desc, zfeature_flags_t flags, const spa_feature_t *deps)
 {
 	zfeature_info_t *feature = &spa_feature_table[fid];
 	static spa_feature_t nodeps[] = { SPA_FEATURE_NONE };
 
 	ASSERT(name != NULL);
 	ASSERT(desc != NULL);
-	ASSERT(!readonly || !mos);
+	ASSERT((flags & ZFEATURE_FLAG_READONLY_COMPAT) == 0 ||
+	    (flags & ZFEATURE_FLAG_MOS) == 0);
 	ASSERT3U(fid, <, SPA_FEATURES);
 	ASSERT(zfeature_is_valid_guid(guid));
 
@@ -154,9 +154,7 @@ zfeature_register(spa_feature_t fid, const char *guid, const char *name,
 	feature->fi_guid = guid;
 	feature->fi_uname = name;
 	feature->fi_desc = desc;
-	feature->fi_can_readonly = readonly;
-	feature->fi_mos = mos;
-	feature->fi_activate_on_enable = activate_on_enable;
+	feature->fi_flags = flags;
 	feature->fi_depends = deps;
 }
 
@@ -165,28 +163,28 @@ zpool_feature_init(void)
 {
 	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
 	    "com.delphix:async_destroy", "async_destroy",
-	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE,
-	    B_FALSE, NULL);
+	    "Destroy filesystems asynchronously.",
+	    ZFEATURE_FLAG_READONLY_COMPAT, NULL);
 
 	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
 	    "com.delphix:empty_bpobj", "empty_bpobj",
-	    "Snapshots use less space.", B_TRUE, B_FALSE,
-	    B_FALSE, NULL);
+	    "Snapshots use less space.",
+	    ZFEATURE_FLAG_READONLY_COMPAT, NULL);
 
 	zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
 	    "org.illumos:lz4_compress", "lz4_compress",
-	    "LZ4 compression algorithm support.", B_FALSE, B_FALSE,
-	    B_TRUE, NULL);
+	    "LZ4 compression algorithm support.",
+	    ZFEATURE_FLAG_ACTIVATE_ON_ENABLE, NULL);
 
 	zfeature_register(SPA_FEATURE_SPACEMAP_HISTOGRAM,
 	    "com.delphix:spacemap_histogram", "spacemap_histogram",
-	    "Spacemaps maintain space histograms.", B_TRUE, B_FALSE,
-	    B_FALSE, NULL);
+	    "Spacemaps maintain space histograms.",
+	    ZFEATURE_FLAG_READONLY_COMPAT, NULL);
 
 	zfeature_register(SPA_FEATURE_ENABLED_TXG,
 	    "com.delphix:enabled_txg", "enabled_txg",
-	    "Record txg at which a feature is enabled", B_TRUE, B_FALSE,
-	    B_FALSE, NULL);
+	    "Record txg at which a feature is enabled",
+	    ZFEATURE_FLAG_READONLY_COMPAT, NULL);
 
 	{
 	static const spa_feature_t hole_birth_deps[] = {
@@ -196,13 +194,14 @@ zpool_feature_init(void)
 	zfeature_register(SPA_FEATURE_HOLE_BIRTH,
 	    "com.delphix:hole_birth", "hole_birth",
 	    "Retain hole birth txg for more precise zfs send",
-	    B_FALSE, B_TRUE, B_TRUE, hole_birth_deps);
+	    ZFEATURE_FLAG_MOS | ZFEATURE_FLAG_ACTIVATE_ON_ENABLE,
+	    hole_birth_deps);
 	}
 
 	zfeature_register(SPA_FEATURE_EXTENSIBLE_DATASET,
 	    "com.delphix:extensible_dataset", "extensible_dataset",
 	    "Enhanced dataset functionality, used by other features.",
-	    B_FALSE, B_FALSE, B_FALSE, NULL);
+	    0, NULL);
 
 	{
 	static const spa_feature_t bookmarks_deps[] = {
@@ -213,7 +212,7 @@ zpool_feature_init(void)
 	zfeature_register(SPA_FEATURE_BOOKMARKS,
 	    "com.delphix:bookmarks", "bookmarks",
 	    "\"zfs bookmark\" command",
-	    B_TRUE, B_FALSE, B_FALSE, bookmarks_deps);
+	    ZFEATURE_FLAG_READONLY_COMPAT, bookmarks_deps);
 	}
 
 	{
@@ -223,14 +222,15 @@ zpool_feature_init(void)
 	};
 	zfeature_register(SPA_FEATURE_FS_SS_LIMIT,
 	    "com.joyent:filesystem_limits", "filesystem_limits",
-	    "Filesystem and snapshot limits.", B_TRUE, B_FALSE, B_FALSE,
-	    filesystem_limits_deps);
+	    "Filesystem and snapshot limits.",
+	    ZFEATURE_FLAG_READONLY_COMPAT, filesystem_limits_deps);
 	}
 
 	zfeature_register(SPA_FEATURE_EMBEDDED_DATA,
 	    "com.delphix:embedded_data", "embedded_data",
 	    "Blocks which compress very well use even less space.",
-	    B_FALSE, B_TRUE, B_TRUE, NULL);
+	    ZFEATURE_FLAG_MOS | ZFEATURE_FLAG_ACTIVATE_ON_ENABLE,
+	    NULL);
 
 	{
 	static const spa_feature_t large_blocks_deps[] = {
@@ -239,7 +239,7 @@ zpool_feature_init(void)
 	};
 	zfeature_register(SPA_FEATURE_LARGE_BLOCKS,
 	    "org.open-zfs:large_blocks", "large_blocks",
-	    "Support for blocks larger than 128KB.", B_FALSE, B_FALSE, B_FALSE,
-	    large_blocks_deps);
+	    "Support for blocks larger than 128KB.",
+	    ZFEATURE_FLAG_PER_DATASET, large_blocks_deps);
 	}
 }