OpenZFS 7230 - add assertions to dmu_send_impl() to verify that stream includes BEGIN and END records

Authored by: Matt Krantz <matt.krantz@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported-by: kernelOfTruth <kerneloftruth@gmail.com>

OpenZFS-issue: https://www.illumos.org/issues/7230
OpenZFS-commit: illumos/illumos-gate@12b90ee2
Closes #5112

Author: kernelOfTruth

include/sys/dmu_impl.h

@@ -273,6 +273,8 @@ typedef struct dmu_sendarg {
 	uint64_t dsa_last_data_offset;
 	uint64_t dsa_resume_object;
 	uint64_t dsa_resume_offset;
+	boolean_t dsa_sent_begin;
+	boolean_t dsa_sent_end;
 } dmu_sendarg_t;
 
 void dmu_object_zapify(objset_t *, uint64_t, dmu_object_type_t, dmu_tx_t *);

module/zfs/dmu_send.c

@@ -169,11 +169,16 @@ dump_record(dmu_sendarg_t *dsp, void *payload, int payload_len)
 	fletcher_4_incremental_native(dsp->dsa_drr,
 	    offsetof(dmu_replay_record_t, drr_u.drr_checksum.drr_checksum),
 	    &dsp->dsa_zc);
-	if (dsp->dsa_drr->drr_type != DRR_BEGIN) {
+	if (dsp->dsa_drr->drr_type == DRR_BEGIN) {
+		dsp->dsa_sent_begin = B_TRUE;
+	} else {
 		ASSERT(ZIO_CHECKSUM_IS_ZERO(&dsp->dsa_drr->drr_u.
 		    drr_checksum.drr_checksum));
 		dsp->dsa_drr->drr_u.drr_checksum.drr_checksum = dsp->dsa_zc;
 	}
+	if (dsp->dsa_drr->drr_type == DRR_END) {
+		dsp->dsa_sent_end = B_TRUE;
+	}
 	fletcher_4_incremental_native(&dsp->dsa_drr->
 	    drr_u.drr_checksum.drr_checksum,
 	    sizeof (zio_cksum_t), &dsp->dsa_zc);
@@ -979,6 +984,8 @@ dmu_send_impl(void *tag, dsl_pool_t *dp, dsl_dataset_t *to_ds,
 	list_remove(&to_ds->ds_sendstreams, dsp);
 	mutex_exit(&to_ds->ds_sendstream_lock);
 
+	VERIFY(err != 0 || (dsp->dsa_sent_begin && dsp->dsa_sent_end));
+
 	kmem_free(drr, sizeof (dmu_replay_record_t));
 	kmem_free(dsp, sizeof (dmu_sendarg_t));