MDEV-31443 [FATAL] InnoDB: Unable to find charset-collation in ibuf_upgrade()

dtype_new_read_for_order_and_null_size(): Correctly assign type->prtype.
This caused the fatal error and crash.

ibuf_merge(): Relax a too strict condition that would result in
[ERROR] InnoDB: Unable to upgrade the change buffer
when there exist buffered changes to redundant secondary indexes, such as
PRIMARY KEY(x), INDEX(x).

ibuf_upgrade(): Modify at most one user tablespace per mini-transaction,
to be crash-safe.

page_cur_insert_rec_zip(), page_cur_delete_rec(): Relax debug assertions
for ibuf_upgrade().

ibuf_log_rebuild_if_needed(): Invoke recv_sys.debug_free() only after
srv_log_rebuild_if_needed() to avoid an assertion failure. This code
is executed when the innodb_log_file_size is changed when upgrading
from 10.x to 11.0.

Tested by: Matthias Leich, Christian Hesse

storage/innobase/ibuf/ibuf0ibuf.cc

@@ -156,7 +156,7 @@ dtype_new_read_for_order_and_null_size(
 		<< 16;
 
 	if (dtype_is_string_type(type->mtype)) {
-		type->prtype |= charset_coll << 16;
+		type->prtype |= charset_coll;
 
 		if (charset_coll == 0) {
 			/* This insert buffer record was inserted before
@@ -709,7 +709,7 @@ static dberr_t ibuf_merge(fil_space_t *space, btr_cur_t *cur, mtr_t *mtr)
     rec_t *rec= cur->page_cur.rec;
     ulint n_fields= rec_get_n_fields_old(rec);
 
-    if (n_fields <= IBUF_REC_FIELD_USER + 1 || rec[4])
+    if (n_fields < IBUF_REC_FIELD_USER + 1 || rec[4])
       return DB_CORRUPTION;
 
     n_fields-= IBUF_REC_FIELD_USER;
@@ -910,7 +910,17 @@ ATTRIBUTE_COLD dberr_t ibuf_upgrade()
         prev_space_id= space_id;
         space= fil_space_t::get(space_id);
         if (space)
+        {
+          /* Move to the next user tablespace. We buffer-fix the current
+          change buffer leaf page to prevent it from being evicted
+          before we have started a new mini-transaction. */
+          cur.page_cur.block->fix();
+          mtr.commit();
+          log_free_check();
+          mtr.start();
+          mtr.page_lock(cur.page_cur.block, RW_X_LATCH);
           mtr.set_named_space(space);
+        }
         spaces++;
       }
       pages++;

storage/innobase/page/page0cur.cc

@@ -1791,7 +1791,8 @@ page_cur_insert_rec_zip(
   ut_ad(rec_offs_comp(offsets));
   ut_ad(fil_page_get_type(page) == FIL_PAGE_INDEX ||
         fil_page_get_type(page) == FIL_PAGE_RTREE);
-  ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + page) == index->id);
+  ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + page) == index->id ||
+        index->is_dummy);
   ut_ad(!page_get_instant(page));
   ut_ad(!page_cur_is_after_last(cursor));
 #ifdef UNIV_ZIP_DEBUG
@@ -2258,7 +2259,7 @@ page_cur_delete_rec(
 	      == index->table->not_redundant());
 	ut_ad(fil_page_index_page_check(block->page.frame));
 	ut_ad(mach_read_from_8(PAGE_HEADER + PAGE_INDEX_ID + block->page.frame)
-	      == index->id);
+	      == index->id || index->is_dummy);
 	ut_ad(mtr->is_named_space(index->table->space));
 
 	/* The record must not be the supremum or infimum record. */

storage/innobase/srv/srv0start.cc

@@ -1165,8 +1165,9 @@ ATTRIBUTE_COLD static dberr_t ibuf_log_rebuild_if_needed()
   if (recv_sys.is_corrupt_log() || recv_sys.is_corrupt_fs())
     return DB_CORRUPTION;
 
+  dberr_t err= srv_log_rebuild_if_needed();
   recv_sys.debug_free();
-  return srv_log_rebuild_if_needed();
+  return err;
 }
 
 static tpool::task_group rollback_all_recovered_group(1);