Fix setting the large_block feature after receiving a snapshot

module/zfs/dsl_dataset.c

@@ -1760,6 +1760,21 @@ dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
 		}
 	}
 
+	/*
+	 * We are not allowed to dirty a filesystem when done receiving
+	 * a snapshot. In this case the flag SPA_FEATURE_LARGE_BLOCKS will
+	 * not be set and a subsequent encrypted raw send will fail. Hence
+	 * activate this feature if needed here.
+	 */
+	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
+		if (zfeature_active(f, ds->ds_feature_activation[f]) &&
+		    !(zfeature_active(f, ds->ds_feature[f]))) {
+			dsl_dataset_activate_feature(dsobj, f,
+			    ds->ds_feature_activation[f], tx);
+			ds->ds_feature[f] = ds->ds_feature_activation[f];
+		}
+	}
+
 	ASSERT3U(ds->ds_prev != 0, ==,
 	    dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
 	if (ds->ds_prev) {

tests/runfiles/common.run

@@ -847,7 +847,7 @@ tests = ['recv_dedup', 'recv_dedup_encrypted_zvol', 'rsend_001_pos',
     'send_realloc_encrypted_files', 'send_spill_block', 'send_holds',
     'send_hole_birth', 'send_mixed_raw', 'send-wR_encrypted_zvol',
     'send_partial_dataset', 'send_invalid', 'send_doall',
-    'send_raw_spill_block', 'send_raw_ashift']
+    'send_raw_spill_block', 'send_raw_ashift', 'send_raw_large_blocks']
 tags = ['functional', 'rsend']
 
 [tests/functional/scrub_mirror]

tests/zfs-tests/tests/Makefile.am

@@ -1811,6 +1811,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/rsend/send_partial_dataset.ksh \
 	functional/rsend/send_raw_ashift.ksh \
 	functional/rsend/send_raw_spill_block.ksh \
+	functional/rsend/send_raw_large_blocks.ksh \
 	functional/rsend/send_realloc_dnode_size.ksh \
 	functional/rsend/send_realloc_encrypted_files.ksh \
 	functional/rsend/send_realloc_files.ksh \

tests/zfs-tests/tests/functional/rsend/send_raw_large_blocks.ksh

@@ -0,0 +1,78 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2022, George Amanakis. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/rsend/rsend.kshlib
+
+#
+# Description:
+# Receiving a snapshot with large blocks and raw sending it succeeds.
+#
+# Strategy:
+# 1) Create a set of files each containing some file data in an
+#	encrypted filesystem with recordsize=1m.
+# 2) Snapshot and send with large_blocks enabled to a new filesystem.
+# 3) Raw send to a file. If the large_blocks feature is not activated
+#	in the filesystem created in (2) the raw send will fail.
+#
+
+verify_runnable "both"
+
+log_assert "Receiving and raw sending a snapshot with large blocks succeeds"
+
+backup=$TEST_BASE_DIR/backup
+raw_backup=$TEST_BASE_DIR/raw_backup
+
+function cleanup
+{
+	log_must rm -f $backup $raw_backup $ibackup $unc_backup
+	destroy_pool pool_lb/fs
+	log_must rm -f $TESTDIR/vdev_a
+}
+
+log_onexit cleanup
+
+typeset passphrase="password"
+typeset file="/pool_lb/fs/$TESTFILE0"
+
+# Create pool
+truncate -s $MINVDEVSIZE $TESTDIR/vdev_a
+log_must zpool create -f -o feature@large_blocks=enabled pool_lb $TESTDIR/vdev_a
+
+log_must eval "echo $passphrase > /pool_lb/pwd"
+
+log_must zfs create -o recordsize=1m pool_lb/fs
+log_must dd if=/dev/urandom of=$file bs=1024 count=1024
+log_must zfs snapshot pool_lb/fs@snap1
+
+log_must eval "zfs send -L pool_lb/fs@snap1 > $backup"
+log_must eval "zfs recv -o encryption=aes-256-ccm -o keyformat=passphrase \
+    -o keylocation=file:///pool_lb/pwd -o primarycache=none \
+    -o recordsize=1m pool_lb/testfs5 < $backup"
+
+log_must eval "zfs send --raw pool_lb/testfs5@snap1 > $raw_backup"
+
+log_pass "Receiving and raw sending a snapshot with large blocks succeeds"