Merge remote branch 'origin/mdb.master' into OPENLDAP_REL_ENG_2_4

libraries/libmdb/mdb.c

@@ -6696,6 +6696,7 @@ int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
 		if (!rc)
 			mdb_close(txn->mt_env, dbi);
 	} else {
+		/* reset the DB record, mark it dirty */
 		txn->mt_dbflags[dbi] |= DB_DIRTY;
 		txn->mt_dbs[dbi].md_depth = 0;
 		txn->mt_dbs[dbi].md_branch_pages = 0;
@@ -6703,6 +6704,20 @@ int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
 		txn->mt_dbs[dbi].md_overflow_pages = 0;
 		txn->mt_dbs[dbi].md_entries = 0;
 		txn->mt_dbs[dbi].md_root = P_INVALID;
+
+		if (!txn->mt_u.dirty_list[0].mid) {
+			MDB_cursor m2;
+			MDB_val key, data;
+			/* make sure we have at least one dirty page in this txn
+			 * otherwise these changes will be ignored.
+			 */
+			key.mv_size = sizeof(txnid_t);
+			key.mv_data = &txn->mt_txnid;
+			data.mv_size = sizeof(MDB_ID);
+			data.mv_data = txn->mt_free_pgs;
+			mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
+			rc = mdb_cursor_put(&m2, &key, &data, 0);
+		}
 	}
 leave:
 	mdb_cursor_close(mc);