MDEV-21098: Assertion failure in rec_get_offsets_func()

The function rec_get_offsets_func() used to hit ut_error
due to an invalid rec_get_status() value of a
ROW_FORMAT!=REDUNDANT record. This fix is twofold:
We will not only avoid a crash on corruption in this case,
but we will also make more effort to validate each record
every time we are iterating over index page records.

rec_get_offsets_func(): Do not crash on a corrupted record.

page_rec_get_nth(): Return nullptr on error.

page_dir_slot_get_rec_validate(): Like page_dir_slot_get_rec(),
but validate the pointer and return nullptr on error.

page_cur_search_with_match(), page_cur_search_with_match_bytes(),
page_dir_split_slot(), page_cur_move_to_next():
Indicate failure in a return value.

page_cur_search(): Replaced with page_cur_search_with_match().

rec_get_next_ptr_const(), rec_get_next_ptr(): Replaced with
page_rec_get_next_low().

TODO: rtr_page_split_initialize_nodes(), rtr_update_mbr_field(),
and possibly other SPATIAL INDEX functions fail to properly handle
errors.

Reviewed by: Thirunarayanan Balathandayuthapani
Tested by: Matthias Leich
Performance tested by: Axel Schwenke

1 files changed, 1 insertions, 71 deletions

diff --git a/storage/innobase/include/rem0rec.inl b/storage/innobase/include/rem0rec.inl
index 30c72a7415a..46c209cbdec 100644
--- a/storage/innobase/include/rem0rec.inl
+++ b/storage/innobase/include/rem0rec.inl
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1994, 2019, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2020, MariaDB Corporation.
+Copyright (c) 2017, 2022, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -204,76 +204,6 @@ rec_set_bit_field_2(
 }
 
 /******************************************************//**
-The following function is used to get the pointer of the next chained record
-on the same page.
-@return pointer to the next chained record, or NULL if none */
-UNIV_INLINE
-const rec_t*
-rec_get_next_ptr_const(
-/*===================*/
-	const rec_t*	rec,	/*!< in: physical record */
-	ulint		comp)	/*!< in: nonzero=compact page format */
-{
-	ulint	field_value;
-
-	compile_time_assert(REC_NEXT_MASK == 0xFFFFUL);
-	compile_time_assert(REC_NEXT_SHIFT == 0);
-
-	field_value = mach_read_from_2(rec - REC_NEXT);
-
-	if (field_value == 0) {
-
-		return(NULL);
-	}
-
-	if (comp) {
-#if UNIV_PAGE_SIZE_MAX <= 32768
-		/* Note that for 64 KiB pages, field_value can 'wrap around'
-		and the debug assertion is not valid */
-
-		/* In the following assertion, field_value is interpreted
-		as signed 16-bit integer in 2's complement arithmetics.
-		If all platforms defined int16_t in the standard headers,
-		the expression could be written simpler as
-		(int16_t) field_value + ut_align_offset(...) < srv_page_size
-		*/
-		ut_ad((field_value >= 32768
-		       ? field_value - 65536
-		       : field_value)
-		      + ut_align_offset(rec, srv_page_size)
-		      < srv_page_size);
-#endif
-		/* There must be at least REC_N_NEW_EXTRA_BYTES + 1
-		between each record. */
-		ut_ad((field_value > REC_N_NEW_EXTRA_BYTES
-		       && field_value < 32768)
-		      || field_value < (uint16) -REC_N_NEW_EXTRA_BYTES);
-
-		return((byte*) ut_align_down(rec, srv_page_size)
-		       + ut_align_offset(rec + field_value, srv_page_size));
-	} else {
-		ut_ad(field_value < srv_page_size);
-
-		return((byte*) ut_align_down(rec, srv_page_size)
-		       + field_value);
-	}
-}
-
-/******************************************************//**
-The following function is used to get the pointer of the next chained record
-on the same page.
-@return pointer to the next chained record, or NULL if none */
-UNIV_INLINE
-rec_t*
-rec_get_next_ptr(
-/*=============*/
-	rec_t*	rec,	/*!< in: physical record */
-	ulint	comp)	/*!< in: nonzero=compact page format */
-{
-	return(const_cast<rec_t*>(rec_get_next_ptr_const(rec, comp)));
-}
-
-/******************************************************//**
 The following function is used to get the offset of the next chained record
 on the same page.
 @return the page offset of the next chained record, or 0 if none */