Add metadata refcount debugging

src/core/channel/census_filter.c

@@ -197,7 +197,7 @@ static void destroy_channel_elem(grpc_channel_element* elem) {
   channel_data* chand = elem->channel_data;
   GPR_ASSERT(chand != NULL);
   if (chand->path_str != NULL) {
-    grpc_mdstr_unref(chand->path_str);
+    GRPC_MDSTR_UNREF(chand->path_str);
   }
 }
 

src/core/channel/http_client_filter.c

@@ -108,13 +108,13 @@ static void hc_mutate_op(grpc_call_element *elem,
       /* Send : prefixed headers, which have to be before any application
          layer headers. */
       grpc_metadata_batch_add_head(&op->data.metadata, &calld->method,
-                                   grpc_mdelem_ref(channeld->method));
+                                   GRPC_MDELEM_REF(channeld->method));
       grpc_metadata_batch_add_head(&op->data.metadata, &calld->scheme,
-                                   grpc_mdelem_ref(channeld->scheme));
+                                   GRPC_MDELEM_REF(channeld->scheme));
       grpc_metadata_batch_add_tail(&op->data.metadata, &calld->te_trailers,
-                                   grpc_mdelem_ref(channeld->te_trailers));
+                                   GRPC_MDELEM_REF(channeld->te_trailers));
       grpc_metadata_batch_add_tail(&op->data.metadata, &calld->content_type,
-                                   grpc_mdelem_ref(channeld->content_type));
+                                   GRPC_MDELEM_REF(channeld->content_type));
       break;
     }
   }
@@ -196,11 +196,11 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   /* grab pointers to our data from the channel element */
   channel_data *channeld = elem->channel_data;
 
-  grpc_mdelem_unref(channeld->te_trailers);
-  grpc_mdelem_unref(channeld->method);
-  grpc_mdelem_unref(channeld->scheme);
-  grpc_mdelem_unref(channeld->content_type);
-  grpc_mdelem_unref(channeld->status);
+  GRPC_MDELEM_UNREF(channeld->te_trailers);
+  GRPC_MDELEM_UNREF(channeld->method);
+  GRPC_MDELEM_UNREF(channeld->scheme);
+  GRPC_MDELEM_UNREF(channeld->content_type);
+  GRPC_MDELEM_UNREF(channeld->status);
 }
 
 const grpc_channel_filter grpc_http_client_filter = {

src/core/channel/http_server_filter.c

@@ -129,9 +129,9 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
     /* translate host to :authority since :authority may be
        omitted */
     grpc_mdelem *authority = grpc_mdelem_from_metadata_strings(
-        channeld->mdctx, grpc_mdstr_ref(channeld->authority_key),
-        grpc_mdstr_ref(md->value));
-    grpc_mdelem_unref(md);
+        channeld->mdctx, GRPC_MDSTR_REF(channeld->authority_key),
+        GRPC_MDSTR_REF(md->value));
+    GRPC_MDELEM_UNREF(md);
     return authority;
   } else {
     return md;
@@ -193,7 +193,7 @@ static void hs_mutate_op(grpc_call_element *elem,
       if (op->type != GRPC_OP_METADATA) continue;
       calld->sent_status = 1;
       grpc_metadata_batch_add_head(&op->data.metadata, &calld->status,
-                                   grpc_mdelem_ref(channeld->status_ok));
+                                   GRPC_MDELEM_REF(channeld->status_ok));
       break;
     }
   }
@@ -264,17 +264,17 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   /* grab pointers to our data from the channel element */
   channel_data *channeld = elem->channel_data;
 
-  grpc_mdelem_unref(channeld->te_trailers);
-  grpc_mdelem_unref(channeld->status_ok);
-  grpc_mdelem_unref(channeld->status_not_found);
-  grpc_mdelem_unref(channeld->method_post);
-  grpc_mdelem_unref(channeld->http_scheme);
-  grpc_mdelem_unref(channeld->https_scheme);
-  grpc_mdelem_unref(channeld->grpc_scheme);
-  grpc_mdelem_unref(channeld->content_type);
-  grpc_mdstr_unref(channeld->path_key);
-  grpc_mdstr_unref(channeld->authority_key);
-  grpc_mdstr_unref(channeld->host_key);
+  GRPC_MDELEM_UNREF(channeld->te_trailers);
+  GRPC_MDELEM_UNREF(channeld->status_ok);
+  GRPC_MDELEM_UNREF(channeld->status_not_found);
+  GRPC_MDELEM_UNREF(channeld->method_post);
+  GRPC_MDELEM_UNREF(channeld->http_scheme);
+  GRPC_MDELEM_UNREF(channeld->https_scheme);
+  GRPC_MDELEM_UNREF(channeld->grpc_scheme);
+  GRPC_MDELEM_UNREF(channeld->content_type);
+  GRPC_MDSTR_UNREF(channeld->path_key);
+  GRPC_MDSTR_UNREF(channeld->authority_key);
+  GRPC_MDSTR_UNREF(channeld->host_key);
 }
 
 const grpc_channel_filter grpc_http_server_filter = {

src/core/security/client_auth_filter.c

@@ -219,11 +219,11 @@ static void auth_start_transport_op(grpc_call_element *elem,
         /* Pointer comparison is OK for md_elems created from the same context.
          */
         if (md->key == chand->authority_string) {
-          if (calld->host != NULL) grpc_mdstr_unref(calld->host);
-          calld->host = grpc_mdstr_ref(md->value);
+          if (calld->host != NULL) GRPC_MDSTR_UNREF(calld->host);
+          calld->host = GRPC_MDSTR_REF(md->value);
         } else if (md->key == chand->path_string) {
-          if (calld->method != NULL) grpc_mdstr_unref(calld->method);
-          calld->method = grpc_mdstr_ref(md->value);
+          if (calld->method != NULL) GRPC_MDSTR_UNREF(calld->method);
+          calld->method = GRPC_MDSTR_REF(md->value);
         }
       }
       if (calld->host != NULL) {
@@ -272,10 +272,10 @@ static void destroy_call_elem(grpc_call_element *elem) {
   call_data *calld = elem->call_data;
   grpc_credentials_unref(calld->creds);
   if (calld->host != NULL) {
-    grpc_mdstr_unref(calld->host);
+    GRPC_MDSTR_UNREF(calld->host);
   }
   if (calld->method != NULL) {
-    grpc_mdstr_unref(calld->method);
+    GRPC_MDSTR_UNREF(calld->method);
   }
 }
 
@@ -314,16 +314,16 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   if (ctx != NULL)
     GRPC_SECURITY_CONNECTOR_UNREF(&ctx->base, "client_auth_filter");
   if (chand->authority_string != NULL) {
-    grpc_mdstr_unref(chand->authority_string);
+    GRPC_MDSTR_UNREF(chand->authority_string);
   }
   if (chand->error_msg_key != NULL) {
-    grpc_mdstr_unref(chand->error_msg_key);
+    GRPC_MDSTR_UNREF(chand->error_msg_key);
   }
   if (chand->status_key != NULL) {
-    grpc_mdstr_unref(chand->status_key);
+    GRPC_MDSTR_UNREF(chand->status_key);
   }
   if (chand->path_string != NULL) {
-    grpc_mdstr_unref(chand->path_string);
+    GRPC_MDSTR_UNREF(chand->path_string);
   }
 }
 

src/core/surface/call.c

@@ -369,18 +369,18 @@ static void destroy_call(void *call, int ignored_success) {
   gpr_mu_destroy(&c->mu);
   for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
     if (c->status[i].details) {
-      grpc_mdstr_unref(c->status[i].details);
+      GRPC_MDSTR_UNREF(c->status[i].details);
     }
   }
   for (i = 0; i < c->owned_metadata_count; i++) {
-    grpc_mdelem_unref(c->owned_metadata[i]);
+    GRPC_MDELEM_UNREF(c->owned_metadata[i]);
   }
   gpr_free(c->owned_metadata);
   for (i = 0; i < GPR_ARRAY_SIZE(c->buffered_metadata); i++) {
     gpr_free(c->buffered_metadata[i].metadata);
   }
   for (i = 0; i < c->send_initial_metadata_count; i++) {
-    grpc_mdelem_unref(c->send_initial_metadata[i].md);
+    GRPC_MDELEM_UNREF(c->send_initial_metadata[i].md);
   }
   for (i = 0; i < GRPC_CONTEXT_COUNT; i++) {
     if (c->context[i].destroy) {
@@ -437,7 +437,7 @@ static void set_decode_compression_level(grpc_call *call,
 static void set_status_details(grpc_call *call, status_source source,
                                grpc_mdstr *status) {
   if (call->status[source].details != NULL) {
-    grpc_mdstr_unref(call->status[source].details);
+    GRPC_MDSTR_UNREF(call->status[source].details);
   }
   call->status[source].details = status;
 }
@@ -616,7 +616,7 @@ static void finish_live_ioreq_op(grpc_call *call, grpc_ioreq_op op,
         case GRPC_IOREQ_SEND_STATUS:
           if (call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details !=
               NULL) {
-            grpc_mdstr_unref(
+            GRPC_MDSTR_UNREF(
                 call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details);
             call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details =
                 NULL;
@@ -945,7 +945,7 @@ static int fill_send_ops(grpc_call *call, grpc_transport_stream_op *op) {
                 &mdb, &call->details_link,
                 grpc_mdelem_from_metadata_strings(
                     call->metadata_context,
-                    grpc_mdstr_ref(
+                    GRPC_MDSTR_REF(
                         grpc_channel_get_message_string(call->channel)),
                     data.send_status.details));
             call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details =
@@ -1053,7 +1053,7 @@ static grpc_call_error start_ioreq(grpc_call *call, const grpc_ioreq *reqs,
                       reqs[i].data.send_status.code);
       if (reqs[i].data.send_status.details) {
         set_status_details(call, STATUS_FROM_SERVER_STATUS,
-                           grpc_mdstr_ref(reqs[i].data.send_status.details));
+                           GRPC_MDSTR_REF(reqs[i].data.send_status.details));
       }
     }
     have_ops |= 1u << op;
@@ -1257,7 +1257,7 @@ static void recv_metadata(grpc_call *call, grpc_metadata_batch *md) {
     if (key == grpc_channel_get_status_string(call->channel)) {
       set_status_code(call, STATUS_FROM_WIRE, decode_status(md));
     } else if (key == grpc_channel_get_message_string(call->channel)) {
-      set_status_details(call, STATUS_FROM_WIRE, grpc_mdstr_ref(md->value));
+      set_status_details(call, STATUS_FROM_WIRE, GRPC_MDSTR_REF(md->value));
     } else if (key ==
                grpc_channel_get_compresssion_level_string(call->channel)) {
       set_decode_compression_level(call, decode_compression(md));
@@ -1293,10 +1293,10 @@ static void recv_metadata(grpc_call *call, grpc_metadata_batch *md) {
 
   grpc_mdctx_lock(mdctx);
   for (l = md->list.head; l; l = l->next) {
-    if (l->md) grpc_mdctx_locked_mdelem_unref(mdctx, l->md);
+    if (l->md) GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
   }
   for (l = md->garbage.head; l; l = l->next) {
-    grpc_mdctx_locked_mdelem_unref(mdctx, l->md);
+    GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
   }
   grpc_mdctx_unlock(mdctx);
 }

src/core/surface/channel.c

@@ -104,7 +104,7 @@ grpc_channel *grpc_channel_create_from_filters(
     char buf[GPR_LTOA_MIN_BUFSIZE];
     gpr_ltoa(i, buf);
     channel->grpc_status_elem[i] = grpc_mdelem_from_metadata_strings(
-        mdctx, grpc_mdstr_ref(channel->grpc_status_string),
+        mdctx, GRPC_MDSTR_REF(channel->grpc_status_string),
         grpc_mdstr_from_string(mdctx, buf));
   }
   channel->path_string = grpc_mdstr_from_string(mdctx, ":path");
@@ -157,10 +157,10 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
   return grpc_channel_create_call_internal(
       channel, cq,
       grpc_mdelem_from_metadata_strings(
-          channel->metadata_context, grpc_mdstr_ref(channel->path_string),
+          channel->metadata_context, GRPC_MDSTR_REF(channel->path_string),
           grpc_mdstr_from_string(channel->metadata_context, method)),
       grpc_mdelem_from_metadata_strings(
-          channel->metadata_context, grpc_mdstr_ref(channel->authority_string),
+          channel->metadata_context, GRPC_MDSTR_REF(channel->authority_string),
           grpc_mdstr_from_string(channel->metadata_context, host)),
       deadline);
 }
@@ -169,10 +169,10 @@ void *grpc_channel_register_call(grpc_channel *channel, const char *method,
                                  const char *host) {
   registered_call *rc = gpr_malloc(sizeof(registered_call));
   rc->path = grpc_mdelem_from_metadata_strings(
-      channel->metadata_context, grpc_mdstr_ref(channel->path_string),
+      channel->metadata_context, GRPC_MDSTR_REF(channel->path_string),
       grpc_mdstr_from_string(channel->metadata_context, method));
   rc->authority = grpc_mdelem_from_metadata_strings(
-      channel->metadata_context, grpc_mdstr_ref(channel->authority_string),
+      channel->metadata_context, GRPC_MDSTR_REF(channel->authority_string),
       grpc_mdstr_from_string(channel->metadata_context, host));
   gpr_mu_lock(&channel->registered_call_mu);
   rc->next = channel->registered_calls;
@@ -186,8 +186,8 @@ grpc_call *grpc_channel_create_registered_call(
     void *registered_call_handle, gpr_timespec deadline) {
   registered_call *rc = registered_call_handle;
   return grpc_channel_create_call_internal(
-      channel, completion_queue, grpc_mdelem_ref(rc->path),
-      grpc_mdelem_ref(rc->authority), deadline);
+      channel, completion_queue, GRPC_MDELEM_REF(rc->path),
+      GRPC_MDELEM_REF(rc->authority), deadline);
 }
 
 #ifdef GRPC_CHANNEL_REF_COUNT_DEBUG
@@ -205,18 +205,18 @@ static void destroy_channel(void *p, int ok) {
   size_t i;
   grpc_channel_stack_destroy(CHANNEL_STACK_FROM_CHANNEL(channel));
   for (i = 0; i < NUM_CACHED_STATUS_ELEMS; i++) {
-    grpc_mdelem_unref(channel->grpc_status_elem[i]);
+    GRPC_MDELEM_UNREF(channel->grpc_status_elem[i]);
   }
-  grpc_mdstr_unref(channel->grpc_status_string);
-  grpc_mdstr_unref(channel->grpc_compression_level_string);
-  grpc_mdstr_unref(channel->grpc_message_string);
-  grpc_mdstr_unref(channel->path_string);
-  grpc_mdstr_unref(channel->authority_string);
+  GRPC_MDSTR_UNREF(channel->grpc_status_string);
+  GRPC_MDSTR_UNREF(channel->grpc_compression_level_string);
+  GRPC_MDSTR_UNREF(channel->grpc_message_string);
+  GRPC_MDSTR_UNREF(channel->path_string);
+  GRPC_MDSTR_UNREF(channel->authority_string);
   while (channel->registered_calls) {
     registered_call *rc = channel->registered_calls;
     channel->registered_calls = rc->next;
-    grpc_mdelem_unref(rc->path);
-    grpc_mdelem_unref(rc->authority);
+    GRPC_MDELEM_UNREF(rc->path);
+    GRPC_MDELEM_UNREF(rc->authority);
     gpr_free(rc);
   }
   grpc_mdctx_unref(channel->metadata_context);
@@ -267,12 +267,12 @@ grpc_mdstr *grpc_channel_get_compresssion_level_string(grpc_channel *channel) {
 
 grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
   if (i >= 0 && i < NUM_CACHED_STATUS_ELEMS) {
-    return grpc_mdelem_ref(channel->grpc_status_elem[i]);
+    return GRPC_MDELEM_REF(channel->grpc_status_elem[i]);
   } else {
     char tmp[GPR_LTOA_MIN_BUFSIZE];
     gpr_ltoa(i, tmp);
     return grpc_mdelem_from_metadata_strings(
-        channel->metadata_context, grpc_mdstr_ref(channel->grpc_status_string),
+        channel->metadata_context, GRPC_MDSTR_REF(channel->grpc_status_string),
         grpc_mdstr_from_string(channel->metadata_context, tmp));
   }
 }

src/core/surface/server.c

@@ -532,10 +532,10 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
   channel_data *chand = elem->channel_data;
   call_data *calld = elem->call_data;
   if (md->key == chand->path_key) {
-    calld->path = grpc_mdstr_ref(md->value);
+    calld->path = GRPC_MDSTR_REF(md->value);
     return NULL;
   } else if (md->key == chand->authority_key) {
-    calld->host = grpc_mdstr_ref(md->value);
+    calld->host = GRPC_MDSTR_REF(md->value);
     return NULL;
   }
   return md;
@@ -710,10 +710,10 @@ static void destroy_call_elem(grpc_call_element *elem) {
   }
 
   if (calld->host) {
-    grpc_mdstr_unref(calld->host);
+    GRPC_MDSTR_UNREF(calld->host);
   }
   if (calld->path) {
-    grpc_mdstr_unref(calld->path);
+    GRPC_MDSTR_UNREF(calld->path);
   }
 
   server_unref(chand->server);
@@ -744,10 +744,10 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   if (chand->registered_methods) {
     for (i = 0; i < chand->registered_method_slots; i++) {
       if (chand->registered_methods[i].method) {
-        grpc_mdstr_unref(chand->registered_methods[i].method);
+        GRPC_MDSTR_UNREF(chand->registered_methods[i].method);
       }
       if (chand->registered_methods[i].host) {
-        grpc_mdstr_unref(chand->registered_methods[i].host);
+        GRPC_MDSTR_UNREF(chand->registered_methods[i].host);
       }
     }
     gpr_free(chand->registered_methods);
@@ -759,8 +759,8 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
     chand->next = chand->prev = chand;
     maybe_finish_shutdown(chand->server);
     gpr_mu_unlock(&chand->server->mu_global);
-    grpc_mdstr_unref(chand->path_key);
-    grpc_mdstr_unref(chand->authority_key);
+    GRPC_MDSTR_UNREF(chand->path_key);
+    GRPC_MDSTR_UNREF(chand->authority_key);
     server_unref(chand->server);
   }
 }

src/core/transport/chttp2/hpack_parser.c

@@ -622,7 +622,7 @@ static const gpr_uint8 inverse_base64[256] = {
 static void on_hdr(grpc_chttp2_hpack_parser *p, grpc_mdelem *md,
                    int add_to_table) {
   if (add_to_table) {
-    grpc_mdelem_ref(md);
+    GRPC_MDELEM_REF(md);
     grpc_chttp2_hptbl_add(&p->table, md);
   }
   p->on_header(p->on_header_user_data, md);
@@ -711,7 +711,7 @@ static int parse_stream_dep0(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
 static int finish_indexed_field(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  grpc_mdelem_ref(md);
+  GRPC_MDELEM_REF(md);
   on_hdr(p, md, 0);
   return parse_begin(p, cur, end);
 }
@@ -740,7 +740,7 @@ static int finish_lithdr_incidx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   on_hdr(p, grpc_mdelem_from_metadata_strings(p->table.mdctx,
-                                              grpc_mdstr_ref(md->key),
+                                              GRPC_MDSTR_REF(md->key),
                                               take_string(p, &p->value)),
          1);
   return parse_begin(p, cur, end);
@@ -793,7 +793,7 @@ static int finish_lithdr_notidx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   on_hdr(p, grpc_mdelem_from_metadata_strings(p->table.mdctx,
-                                              grpc_mdstr_ref(md->key),
+                                              GRPC_MDSTR_REF(md->key),
                                               take_string(p, &p->value)),
          0);
   return parse_begin(p, cur, end);
@@ -846,7 +846,7 @@ static int finish_lithdr_nvridx(grpc_chttp2_hpack_parser *p,
                                 const gpr_uint8 *cur, const gpr_uint8 *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   on_hdr(p, grpc_mdelem_from_metadata_strings(p->table.mdctx,
-                                              grpc_mdstr_ref(md->key),
+                                              GRPC_MDSTR_REF(md->key),
                                               take_string(p, &p->value)),
          0);
   return parse_begin(p, cur, end);
@@ -1339,7 +1339,7 @@ static void on_header_not_set(void *user_data, grpc_mdelem *md) {
           valuehex);
   gpr_free(keyhex);
   gpr_free(valuehex);
-  grpc_mdelem_unref(md);
+  GRPC_MDELEM_UNREF(md);
   abort();
 }
 

src/core/transport/chttp2/hpack_table.c

@@ -122,10 +122,10 @@ void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl, grpc_mdctx *mdctx) {
 void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl *tbl) {
   size_t i;
   for (i = 0; i < GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
-    grpc_mdelem_unref(tbl->static_ents[i]);
+    GRPC_MDELEM_UNREF(tbl->static_ents[i]);
   }
   for (i = 0; i < tbl->num_ents; i++) {
-    grpc_mdelem_unref(
+    GRPC_MDELEM_UNREF(
         tbl->ents[(tbl->first_ent + i) % GRPC_CHTTP2_MAX_TABLE_COUNT]);
   }
 }
@@ -155,7 +155,7 @@ static void evict1(grpc_chttp2_hptbl *tbl) {
                    GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
   tbl->first_ent = (tbl->first_ent + 1) % GRPC_CHTTP2_MAX_TABLE_COUNT;
   tbl->num_ents--;
-  grpc_mdelem_unref(first_ent);
+  GRPC_MDELEM_UNREF(first_ent);
 }
 
 void grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {

src/core/transport/chttp2/incoming_metadata.c

@@ -49,7 +49,7 @@ void grpc_chttp2_incoming_metadata_buffer_destroy(
     grpc_chttp2_incoming_metadata_buffer *buffer) {
   size_t i;
   for (i = 0; i < buffer->count; i++) {
-    grpc_mdelem_unref(buffer->elems[i].md);
+    GRPC_MDELEM_UNREF(buffer->elems[i].md);
   }
   gpr_free(buffer->elems);
 }

src/core/transport/chttp2/parsing.c

@@ -463,7 +463,7 @@ static grpc_chttp2_parse_error skip_parser(
   return GRPC_CHTTP2_PARSE_OK;
 }
 
-static void skip_header(void *tp, grpc_mdelem *md) { grpc_mdelem_unref(md); }
+static void skip_header(void *tp, grpc_mdelem *md) { GRPC_MDELEM_UNREF(md); }
 
 static int init_skip_frame_parser(
     grpc_chttp2_transport_parsing *transport_parsing, int is_header) {
@@ -600,7 +600,7 @@ static void on_header(void *tp, grpc_mdelem *md) {
     grpc_chttp2_incoming_metadata_buffer_set_deadline(
         &stream_parsing->incoming_metadata,
         gpr_time_add(gpr_now(), *cached_timeout));
-    grpc_mdelem_unref(md);
+    GRPC_MDELEM_UNREF(md);
   } else {
     grpc_chttp2_incoming_metadata_buffer_add(&stream_parsing->incoming_metadata,
                                              md);

src/core/transport/chttp2/stream_encoder.c

@@ -247,19 +247,19 @@ static grpc_mdelem *add_elem(grpc_chttp2_hpack_compressor *c,
   } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key) {
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   } else if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == NULL) {
-    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = grpc_mdstr_ref(elem->key);
+    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
   } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == NULL) {
-    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = grpc_mdstr_ref(elem->key);
+    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   } else if (c->indices_keys[HASH_FRAGMENT_2(key_hash)] <
              c->indices_keys[HASH_FRAGMENT_3(key_hash)]) {
-    grpc_mdstr_unref(c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
-    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = grpc_mdstr_ref(elem->key);
+    GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
+    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
   } else {
-    grpc_mdstr_unref(c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
-    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = grpc_mdstr_ref(elem->key);
+    GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
+    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   }
 
@@ -439,10 +439,10 @@ static void deadline_enc(grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
   grpc_mdelem *mdelem;
   grpc_chttp2_encode_timeout(gpr_time_sub(deadline, gpr_now()), timeout_str);
   mdelem = grpc_mdelem_from_metadata_strings(
-      c->mdctx, grpc_mdstr_ref(c->timeout_key_str),
+      c->mdctx, GRPC_MDSTR_REF(c->timeout_key_str),
       grpc_mdstr_from_string(c->mdctx, timeout_str));
   mdelem = hpack_enc(c, mdelem, st);
-  if (mdelem) grpc_mdelem_unref(mdelem);
+  if (mdelem) GRPC_MDELEM_UNREF(mdelem);
 }
 
 gpr_slice grpc_chttp2_data_frame_create_empty_close(gpr_uint32 id) {
@@ -461,10 +461,10 @@ void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c,
 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) {
   int i;
   for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_VALUES; i++) {
-    if (c->entries_keys[i]) grpc_mdstr_unref(c->entries_keys[i]);
-    if (c->entries_elems[i]) grpc_mdelem_unref(c->entries_elems[i]);
+    if (c->entries_keys[i]) GRPC_MDSTR_UNREF(c->entries_keys[i]);
+    if (c->entries_elems[i]) GRPC_MDELEM_UNREF(c->entries_elems[i]);
   }
-  grpc_mdstr_unref(c->timeout_key_str);
+  GRPC_MDSTR_UNREF(c->timeout_key_str);
 }
 
 gpr_uint32 grpc_chttp2_preencode(grpc_stream_op *inops, size_t *inops_count,
@@ -620,10 +620,10 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
       op = &ops[unref_op];
       if (op->type != GRPC_OP_METADATA) continue;
       for (l = op->data.metadata.list.head; l; l = l->next) {
-        if (l->md) grpc_mdctx_locked_mdelem_unref(mdctx, l->md);
+        if (l->md) GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
       }
       for (l = op->data.metadata.garbage.head; l; l = l->next) {
-        grpc_mdctx_locked_mdelem_unref(mdctx, l->md);
+        GRPC_MDCTX_LOCKED_MDELEM_UNREF(mdctx, l->md);
       }
     }
     grpc_mdctx_unlock(mdctx);

src/core/transport/chttp2_transport.c

@@ -139,7 +139,7 @@ static void destruct_transport(grpc_chttp2_transport *t) {
   grpc_chttp2_hpack_parser_destroy(&t->parsing.hpack_parser);
   grpc_chttp2_goaway_parser_destroy(&t->parsing.goaway_parser);
 
-  grpc_mdstr_unref(t->parsing.str_grpc_timeout);
+  GRPC_MDSTR_UNREF(t->parsing.str_grpc_timeout);
 
   for (i = 0; i < STREAM_LIST_COUNT; i++) {
     GPR_ASSERT(t->lists[i].head == NULL);

src/core/transport/metadata.c

@@ -48,6 +48,20 @@
 #define INITIAL_STRTAB_CAPACITY 4
 #define INITIAL_MDTAB_CAPACITY 4
 
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+#define DEBUG_ARGS , const char *file, int line
+#define FWD_DEBUG_ARGS , file, line
+#define INTERNAL_STRING_REF(s) internal_string_ref((s), __FILE__, __LINE__)
+#define INTERNAL_STRING_UNREF(s) internal_string_unref((s), __FILE__, __LINE__)
+#define REF_MD_LOCKED(s) ref_md_locked((s), __FILE__, __LINE__)
+#else
+#define DEBUG_ARGS
+#define FWD_DEBUG_ARGS
+#define INTERNAL_STRING_REF(s) internal_string_ref((s))
+#define INTERNAL_STRING_UNREF(s) internal_string_unref((s))
+#define REF_MD_LOCKED(s) ref_md_locked((s))
+#endif
+
 typedef struct internal_string {
   /* must be byte compatible with grpc_mdstr */
   gpr_slice slice;
@@ -96,8 +110,8 @@ struct grpc_mdctx {
   size_t mdtab_capacity;
 };
 
-static void internal_string_ref(internal_string *s);
-static void internal_string_unref(internal_string *s);
+static void internal_string_ref(internal_string *s DEBUG_ARGS);
+static void internal_string_unref(internal_string *s DEBUG_ARGS);
 static void discard_metadata(grpc_mdctx *ctx);
 static void gc_mdtab(grpc_mdctx *ctx);
 static void metadata_context_destroy_locked(grpc_mdctx *ctx);
@@ -132,7 +146,15 @@ static void unlock(grpc_mdctx *ctx) {
   gpr_mu_unlock(&ctx->mu);
 }
 
-static void ref_md_locked(internal_metadata *md) {
+static void ref_md_locked(internal_metadata *md DEBUG_ARGS) {
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "ELM   REF:%p:%d->%d: '%s' = '%s'", md,
+          gpr_atm_no_barrier_load(&md->refcnt),
+          gpr_atm_no_barrier_load(&md->refcnt) + 1,
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->key),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->value));
+#endif
   if (0 == gpr_atm_no_barrier_fetch_add(&md->refcnt, 1)) {
     md->context->mdtab_free--;
   }
@@ -173,8 +195,8 @@ static void discard_metadata(grpc_mdctx *ctx) {
     while (cur) {
       GPR_ASSERT(gpr_atm_acq_load(&cur->refcnt) == 0);
       next = cur->bucket_next;
-      internal_string_unref(cur->key);
-      internal_string_unref(cur->value);
+      INTERNAL_STRING_UNREF(cur->key);
+      INTERNAL_STRING_UNREF(cur->value);
       if (cur->user_data) {
         cur->destroy_user_data(cur->user_data);
       }
@@ -248,9 +270,19 @@ static void internal_destroy_string(internal_string *is) {
   gpr_free(is);
 }
 
-static void internal_string_ref(internal_string *s) { ++s->refs; }
+static void internal_string_ref(internal_string *s DEBUG_ARGS) {
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "STR   REF:%p:%d->%d: '%s'", s,
+          s->refs, s->refs + 1, grpc_mdstr_as_c_string((grpc_mdstr *)s));
+#endif
+  ++s->refs;
+}
 
-static void internal_string_unref(internal_string *s) {
+static void internal_string_unref(internal_string *s DEBUG_ARGS) {
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG, "STR UNREF:%p:%d->%d: '%s'", s,
+          s->refs, s->refs - 1, grpc_mdstr_as_c_string((grpc_mdstr *)s));
+#endif
   GPR_ASSERT(s->refs > 0);
   if (0 == --s->refs) {
     internal_destroy_string(s);
@@ -262,7 +294,7 @@ static void slice_ref(void *p) {
       (internal_string *)((char *)p - offsetof(internal_string, refcount));
   grpc_mdctx *ctx = is->context;
   lock(ctx);
-  internal_string_ref(is);
+  INTERNAL_STRING_REF(is);
   unlock(ctx);
 }
 
@@ -271,7 +303,7 @@ static void slice_unref(void *p) {
       (internal_string *)((char *)p - offsetof(internal_string, refcount));
   grpc_mdctx *ctx = is->context;
   lock(ctx);
-  internal_string_unref(is);
+  INTERNAL_STRING_UNREF(is);
   unlock(ctx);
 }
 
@@ -297,7 +329,7 @@ grpc_mdstr *grpc_mdstr_from_buffer(grpc_mdctx *ctx, const gpr_uint8 *buf,
   for (s = ctx->strtab[hash % ctx->strtab_capacity]; s; s = s->bucket_next) {
     if (s->hash == hash && GPR_SLICE_LENGTH(s->slice) == length &&
         0 == memcmp(buf, GPR_SLICE_START_PTR(s->slice), length)) {
-      internal_string_ref(s);
+      INTERNAL_STRING_REF(s);
       unlock(ctx);
       return (grpc_mdstr *)s;
     }
@@ -353,8 +385,8 @@ static void gc_mdtab(grpc_mdctx *ctx) {
     for (md = ctx->mdtab[i]; md; md = next) {
       next = md->bucket_next;
       if (gpr_atm_acq_load(&md->refcnt) == 0) {
-        internal_string_unref(md->key);
-        internal_string_unref(md->value);
+        INTERNAL_STRING_UNREF(md->key);
+        INTERNAL_STRING_UNREF(md->value);
         if (md->user_data) {
           md->destroy_user_data(md->user_data);
         }
@@ -418,9 +450,9 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdctx *ctx,
   /* search for an existing pair */
   for (md = ctx->mdtab[hash % ctx->mdtab_capacity]; md; md = md->bucket_next) {
     if (md->key == key && md->value == value) {
-      ref_md_locked(md);
-      internal_string_unref(key);
-      internal_string_unref(value);
+      REF_MD_LOCKED(md);
+      INTERNAL_STRING_UNREF(key);
+      INTERNAL_STRING_UNREF(value);
       unlock(ctx);
       return (grpc_mdelem *)md;
     }
@@ -435,6 +467,12 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdctx *ctx,
   md->user_data = NULL;
   md->destroy_user_data = NULL;
   md->bucket_next = ctx->mdtab[hash % ctx->mdtab_capacity];
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(GPR_DEBUG, "ELM   NEW:%p:%d: '%s' = '%s'", md,
+          gpr_atm_no_barrier_load(&md->refcnt),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->key),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->value));
+#endif
   ctx->mdtab[hash % ctx->mdtab_capacity] = md;
   ctx->mdtab_count++;
 
@@ -469,8 +507,16 @@ grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_mdctx *ctx,
       grpc_mdstr_from_buffer(ctx, value, value_length));
 }
 
-grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *gmd) {
+grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *gmd DEBUG_ARGS) {
   internal_metadata *md = (internal_metadata *)gmd;
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "ELM   REF:%p:%d->%d: '%s' = '%s'", md,
+          gpr_atm_no_barrier_load(&md->refcnt),
+          gpr_atm_no_barrier_load(&md->refcnt) + 1,
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->key),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->value));
+#endif
   /* we can assume the ref count is >= 1 as the application is calling
      this function - meaning that no adjustment to mdtab_free is necessary,
      simplifying the logic here to be just an atomic increment */
@@ -480,10 +526,18 @@ grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *gmd) {
   return gmd;
 }
 
-void grpc_mdelem_unref(grpc_mdelem *gmd) {
+void grpc_mdelem_unref(grpc_mdelem *gmd DEBUG_ARGS) {
   internal_metadata *md = (internal_metadata *)gmd;
   grpc_mdctx *ctx = md->context;
   lock(ctx);
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "ELM UNREF:%p:%d->%d: '%s' = '%s'", md,
+          gpr_atm_no_barrier_load(&md->refcnt),
+          gpr_atm_no_barrier_load(&md->refcnt) - 1,
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->key),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->value));
+#endif
   assert(gpr_atm_no_barrier_load(&md->refcnt) >= 1);
   if (1 == gpr_atm_full_fetch_add(&md->refcnt, -1)) {
     ctx->mdtab_free++;
@@ -495,20 +549,20 @@ const char *grpc_mdstr_as_c_string(grpc_mdstr *s) {
   return (const char *)GPR_SLICE_START_PTR(s->slice);
 }
 
-grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *gs) {
+grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *gs DEBUG_ARGS) {
   internal_string *s = (internal_string *)gs;
   grpc_mdctx *ctx = s->context;
   lock(ctx);
-  internal_string_ref(s);
+  internal_string_ref(s FWD_DEBUG_ARGS);
   unlock(ctx);
   return gs;
 }
 
-void grpc_mdstr_unref(grpc_mdstr *gs) {
+void grpc_mdstr_unref(grpc_mdstr *gs DEBUG_ARGS) {
   internal_string *s = (internal_string *)gs;
   grpc_mdctx *ctx = s->context;
   lock(ctx);
-  internal_string_unref(s);
+  internal_string_unref(s FWD_DEBUG_ARGS);
   unlock(ctx);
 }
 
@@ -558,10 +612,19 @@ gpr_slice grpc_mdstr_as_base64_encoded_and_huffman_compressed(grpc_mdstr *gs) {
 
 void grpc_mdctx_lock(grpc_mdctx *ctx) { lock(ctx); }
 
-void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx, grpc_mdelem *gmd) {
+void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx,
+                                    grpc_mdelem *gmd DEBUG_ARGS) {
   internal_metadata *md = (internal_metadata *)gmd;
   grpc_mdctx *elem_ctx = md->context;
   GPR_ASSERT(ctx == elem_ctx);
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+  gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+          "ELM UNREF:%p:%d->%d: '%s' = '%s'", md,
+          gpr_atm_no_barrier_load(&md->refcnt),
+          gpr_atm_no_barrier_load(&md->refcnt) - 1,
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->key),
+          grpc_mdstr_as_c_string((grpc_mdstr *)md->value));
+#endif
   assert(gpr_atm_no_barrier_load(&md->refcnt) >= 1);
   if (1 == gpr_atm_full_fetch_add(&md->refcnt, -1)) {
     ctx->mdtab_free++;

src/core/transport/metadata.h

@@ -127,11 +127,25 @@ void grpc_mdelem_set_user_data(grpc_mdelem *md, void (*destroy_func)(void *),
                                void *user_data);
 
 /* Reference counting */
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+#define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s), __FILE__, __LINE__)
+#define GRPC_MDSTR_UNREF(s) grpc_mdstr_unref((s), __FILE__, __LINE__)
+#define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s), __FILE__, __LINE__)
+#define GRPC_MDELEM_UNREF(s) grpc_mdelem_unref((s), __FILE__, __LINE__)
+grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s, const char *file, int line);
+void grpc_mdstr_unref(grpc_mdstr *s, const char *file, int line);
+grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md, const char *file, int line);
+void grpc_mdelem_unref(grpc_mdelem *md, const char *file, int line);
+#else
+#define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s))
+#define GRPC_MDSTR_UNREF(s) grpc_mdstr_unref((s))
+#define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s))
+#define GRPC_MDELEM_UNREF(s) grpc_mdelem_unref((s))
 grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s);
 void grpc_mdstr_unref(grpc_mdstr *s);
-
 grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md);
 void grpc_mdelem_unref(grpc_mdelem *md);
+#endif
 
 /* Recover a char* from a grpc_mdstr. The returned string is null terminated.
    Does not promise that the returned string has no embedded nulls however. */
@@ -147,8 +161,18 @@ int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
 /* Lock the metadata context: it's only safe to call _locked_ functions against
    this context from the calling thread until grpc_mdctx_unlock is called */
 void grpc_mdctx_lock(grpc_mdctx *ctx);
+#ifdef GRPC_METADATA_REFCOUNT_DEBUG
+#define GRPC_MDCTX_LOCKED_MDELEM_UNREF(ctx, elem) \
+  grpc_mdctx_locked_mdelem_unref((ctx), (elem), __FILE__, __LINE__)
+/* Unref a metadata element */
+void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx, grpc_mdelem *elem,
+                                    const char *file, int line);
+#else
+#define GRPC_MDCTX_LOCKED_MDELEM_UNREF(ctx, elem) \
+  grpc_mdctx_locked_mdelem_unref((ctx), (elem))
 /* Unref a metadata element */
 void grpc_mdctx_locked_mdelem_unref(grpc_mdctx *ctx, grpc_mdelem *elem);
+#endif
 /* Unlock the metadata context */
 void grpc_mdctx_unlock(grpc_mdctx *ctx);
 

src/core/transport/stream_op.c

@@ -211,10 +211,10 @@ void grpc_metadata_batch_init(grpc_metadata_batch *batch) {
 void grpc_metadata_batch_destroy(grpc_metadata_batch *batch) {
   grpc_linked_mdelem *l;
   for (l = batch->list.head; l; l = l->next) {
-    grpc_mdelem_unref(l->md);
+    GRPC_MDELEM_UNREF(l->md);
   }
   for (l = batch->garbage.head; l; l = l->next) {
-    grpc_mdelem_unref(l->md);
+    GRPC_MDELEM_UNREF(l->md);
   }
 }
 
@@ -315,7 +315,7 @@ void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
       assert_valid_list(&batch->list);
       link_head(&batch->garbage, l);
     } else if (filt != orig) {
-      grpc_mdelem_unref(orig);
+      GRPC_MDELEM_UNREF(orig);
       l->md = filt;
     }
   }

src/core/transport/transport.c

@@ -85,6 +85,6 @@ void grpc_transport_stream_op_add_cancellation(grpc_transport_stream_op *op,
     op->cancel_with_status = status;
   }
   if (message) {
-    grpc_mdstr_unref(message);
+    GRPC_MDSTR_UNREF(message);
   }
 }

test/core/transport/chttp2/hpack_parser_test.c

@@ -53,7 +53,7 @@ static void onhdr(void *ud, grpc_mdelem *md) {
   GPR_ASSERT(evalue);
   GPR_ASSERT(gpr_slice_str_cmp(md->key->slice, ekey) == 0);
   GPR_ASSERT(gpr_slice_str_cmp(md->value->slice, evalue) == 0);
-  grpc_mdelem_unref(md);
+  GRPC_MDELEM_UNREF(md);
 }
 
 static void test_vector(grpc_chttp2_hpack_parser *parser,

test/core/transport/chttp2/hpack_table_test.c

@@ -167,7 +167,7 @@ static grpc_chttp2_hptbl_find_result find_simple(grpc_chttp2_hptbl *tbl,
                                                  const char *value) {
   grpc_mdelem *md = grpc_mdelem_from_strings(tbl->mdctx, key, value);
   grpc_chttp2_hptbl_find_result r = grpc_chttp2_hptbl_find(tbl, md);
-  grpc_mdelem_unref(md);
+  GRPC_MDELEM_UNREF(md);
   return r;
 }
 

test/core/transport/chttp2/stream_encoder_test.c

@@ -266,7 +266,7 @@ static void chk_hdr(void *p, grpc_mdelem *el) {
   GPR_ASSERT(0 == gpr_slice_str_cmp(el->key->slice, st->key));
   GPR_ASSERT(0 == gpr_slice_str_cmp(el->value->slice, st->value));
   st->got_hdr = 1;
-  grpc_mdelem_unref(el);
+  GRPC_MDELEM_UNREF(el);
 }
 
 static void test_decode_random_headers_inner(int max_len) {

test/core/transport/metadata_test.c

@@ -70,10 +70,10 @@ static void test_create_string(void) {
   GPR_ASSERT(s3 != s1);
   GPR_ASSERT(gpr_slice_str_cmp(s1->slice, "hello") == 0);
   GPR_ASSERT(gpr_slice_str_cmp(s3->slice, "very much not hello") == 0);
-  grpc_mdstr_unref(s1);
-  grpc_mdstr_unref(s2);
+  GRPC_MDSTR_UNREF(s1);
+  GRPC_MDSTR_UNREF(s2);
   grpc_mdctx_unref(ctx);
-  grpc_mdstr_unref(s3);
+  GRPC_MDSTR_UNREF(s3);
 }
 
 static void test_create_metadata(void) {
@@ -93,9 +93,9 @@ static void test_create_metadata(void) {
   GPR_ASSERT(gpr_slice_str_cmp(m1->key->slice, "a") == 0);
   GPR_ASSERT(gpr_slice_str_cmp(m1->value->slice, "b") == 0);
   GPR_ASSERT(gpr_slice_str_cmp(m3->value->slice, "c") == 0);
-  grpc_mdelem_unref(m1);
-  grpc_mdelem_unref(m2);
-  grpc_mdelem_unref(m3);
+  GRPC_MDELEM_UNREF(m1);
+  GRPC_MDELEM_UNREF(m2);
+  GRPC_MDELEM_UNREF(m3);
   grpc_mdctx_unref(ctx);
 }
 
@@ -112,7 +112,7 @@ static void test_create_many_ephemeral_metadata(void) {
   /* add, and immediately delete a bunch of different elements */
   for (i = 0; i < MANY; i++) {
     gpr_ltoa(i, buffer);
-    grpc_mdelem_unref(grpc_mdelem_from_strings(ctx, "a", buffer));
+    GRPC_MDELEM_UNREF(grpc_mdelem_from_strings(ctx, "a", buffer));
   }
   /* capacity should not grow */
   GPR_ASSERT(mdtab_capacity_before ==
@@ -140,11 +140,11 @@ static void test_create_many_persistant_metadata(void) {
     gpr_ltoa(i, buffer);
     md = grpc_mdelem_from_strings(ctx, "a", buffer);
     GPR_ASSERT(md == created[i]);
-    grpc_mdelem_unref(md);
+    GRPC_MDELEM_UNREF(md);
   }
   /* cleanup phase */
   for (i = 0; i < MANY; i++) {
-    grpc_mdelem_unref(created[i]);
+    GRPC_MDELEM_UNREF(created[i]);
   }
   grpc_mdctx_unref(ctx);
 
@@ -160,15 +160,15 @@ static void test_spin_creating_the_same_thing(void) {
   GPR_ASSERT(grpc_mdctx_get_mdtab_count_test_only(ctx) == 0);
   GPR_ASSERT(grpc_mdctx_get_mdtab_free_test_only(ctx) == 0);
 
-  grpc_mdelem_unref(grpc_mdelem_from_strings(ctx, "a", "b"));
+  GRPC_MDELEM_UNREF(grpc_mdelem_from_strings(ctx, "a", "b"));
   GPR_ASSERT(grpc_mdctx_get_mdtab_count_test_only(ctx) == 1);
   GPR_ASSERT(grpc_mdctx_get_mdtab_free_test_only(ctx) == 1);
 
-  grpc_mdelem_unref(grpc_mdelem_from_strings(ctx, "a", "b"));
+  GRPC_MDELEM_UNREF(grpc_mdelem_from_strings(ctx, "a", "b"));
   GPR_ASSERT(grpc_mdctx_get_mdtab_count_test_only(ctx) == 1);
   GPR_ASSERT(grpc_mdctx_get_mdtab_free_test_only(ctx) == 1);
 
-  grpc_mdelem_unref(grpc_mdelem_from_strings(ctx, "a", "b"));
+  GRPC_MDELEM_UNREF(grpc_mdelem_from_strings(ctx, "a", "b"));
   GPR_ASSERT(grpc_mdctx_get_mdtab_count_test_only(ctx) == 1);
   GPR_ASSERT(grpc_mdctx_get_mdtab_free_test_only(ctx) == 1);
 
@@ -196,8 +196,8 @@ static void test_things_stick_around(void) {
   }
 
   for (i = 0; i < nstrs; i++) {
-    grpc_mdstr_ref(strs[i]);
-    grpc_mdstr_unref(strs[i]);
+    GRPC_MDSTR_REF(strs[i]);
+    GRPC_MDSTR_UNREF(strs[i]);
   }
 
   for (i = 0; i < nstrs; i++) {
@@ -209,12 +209,12 @@ static void test_things_stick_around(void) {
   }
 
   for (i = 0; i < nstrs; i++) {
-    grpc_mdstr_unref(strs[shuf[i]]);
+    GRPC_MDSTR_UNREF(strs[shuf[i]]);
     for (j = i + 1; j < nstrs; j++) {
       gpr_asprintf(&buffer, "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx%dx", shuf[j]);
       test = grpc_mdstr_from_string(ctx, buffer);
       GPR_ASSERT(test == strs[shuf[j]]);
-      grpc_mdstr_unref(test);
+      GRPC_MDSTR_UNREF(test);
       gpr_free(buffer);
     }
   }
@@ -237,14 +237,14 @@ static void test_slices_work(void) {
   str = grpc_mdstr_from_string(
       ctx, "123456789012345678901234567890123456789012345678901234567890");
   slice = gpr_slice_ref(str->slice);
-  grpc_mdstr_unref(str);
+  GRPC_MDSTR_UNREF(str);
   gpr_slice_unref(slice);
 
   str = grpc_mdstr_from_string(
       ctx, "123456789012345678901234567890123456789012345678901234567890");
   slice = gpr_slice_ref(str->slice);
   gpr_slice_unref(slice);
-  grpc_mdstr_unref(str);
+  GRPC_MDSTR_UNREF(str);
 
   grpc_mdctx_unref(ctx);
 }
@@ -264,7 +264,7 @@ static void test_base64_and_huffman_works(void) {
   GPR_ASSERT(0 == gpr_slice_cmp(slice1, slice2));
 
   gpr_slice_unref(slice2);
-  grpc_mdstr_unref(str);
+  GRPC_MDSTR_UNREF(str);
   grpc_mdctx_unref(ctx);
 }