Activate per-dataset feature flags when the property is set

If a compression or checksum algorithm requires a feature flag,
activate the feature as soon as the property is set, rather than
waiting for the first block to be born.

Signed-off-by: Allan Jude <allan@klarasystems.com>

Author: allanjude

module/zfs/dsl_prop.c

@@ -35,6 +35,8 @@
 #include <sys/dsl_synctask.h>
 #include <sys/spa.h>
 #include <sys/zap.h>
+#include <sys/zio_checksum.h>
+#include <sys/zio_compress.h>
 #include <sys/fs/zfs.h>
 
 #include "zfs_prop.h"
@@ -662,8 +664,11 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 	char *tbuf = NULL;
 	int err;
 	uint64_t version = spa_version(ds->ds_dir->dd_pool->dp_spa);
+	spa_feature_t f;
+	zfs_prop_t prop;
 
-	isint = (dodefault(zfs_name_to_prop(propname), 8, 1, &intval) == 0);
+	prop = zfs_name_to_prop(propname);
+	isint = (dodefault(prop, 8, 1, &intval) == 0);
 
 	if (ds->ds_is_snapshot) {
 		ASSERT(version >= SPA_VERSION_SNAP_PROPS);
@@ -813,6 +818,29 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 		}
 	}
 
+	switch (prop) {
+	case ZFS_PROP_COMPRESSION:
+		f = zio_compress_to_feature(ZIO_COMPRESS_ALGO(intval));
+		if (f != SPA_FEATURE_NONE) {
+			ASSERT3S(spa_feature_table[f].fi_type, ==,
+			    ZFEATURE_TYPE_BOOLEAN);
+			ds->ds_feature_activation[f] = (void *)B_TRUE;
+			dsl_dataset_dirty(ds, tx);
+		}
+		break;
+	case ZFS_PROP_CHECKSUM:
+		f = zio_checksum_to_feature(intval);
+		if (f != SPA_FEATURE_NONE) {
+			ASSERT3S(spa_feature_table[f].fi_type, ==,
+			    ZFEATURE_TYPE_BOOLEAN);
+			ds->ds_feature_activation[f] = (void *)B_TRUE;
+			dsl_dataset_dirty(ds, tx);
+		}
+		break;
+	default:
+		break;
+	}
+
 	spa_history_log_internal_ds(ds, (source == ZPROP_SRC_NONE ||
 	    source == ZPROP_SRC_INHERITED) ? "inherit" : "set", tx,
 	    "%s=%s", propname, (valstr == NULL ? "" : valstr));