Cleanup: Remove BTR_MODIFY_EXTERNAL

btr_blob_log_check_t::check(): Acquire an index U-latch upfront and
pass the flag BTR_MODIFY_LEAF_ALREADY_LATCHED to the search.

storage/innobase/btr/btr0cur.cc

@@ -1254,7 +1254,6 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 	ulint		root_height = 0; /* remove warning */
 
 	btr_intention_t	lock_intention;
-	bool		modify_external;
 	buf_block_t*	tree_blocks[BTR_MAX_LEVELS];
 	ulint		tree_savepoints[BTR_MAX_LEVELS];
 	ulint		n_blocks = 0;
@@ -1303,11 +1302,9 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 	cursor->low_match = ULINT_UNDEFINED;
 #endif /* UNIV_DEBUG */
 
-	ibool	s_latch_by_caller;
+	const bool latch_by_caller = latch_mode & BTR_ALREADY_S_LATCHED;
 
-	s_latch_by_caller = latch_mode & BTR_ALREADY_S_LATCHED;
-
-	ut_ad(!s_latch_by_caller
+	ut_ad(!latch_by_caller
 	      || srv_read_only_mode
 	      || mtr->memo_contains_flagged(&index->lock, MTR_MEMO_S_LOCK
 					    | MTR_MEMO_SX_LOCK));
@@ -1344,14 +1341,10 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 
 	lock_intention = btr_cur_get_and_clear_intention(&latch_mode);
 
-	modify_external = latch_mode & BTR_MODIFY_EXTERNAL;
-
 	/* Turn the flags unrelated to the latch mode off. */
 	latch_mode = BTR_LATCH_MODE_WITHOUT_FLAGS(latch_mode);
 
-	ut_ad(!modify_external || latch_mode == BTR_MODIFY_LEAF);
-
-	ut_ad(!s_latch_by_caller
+	ut_ad(!latch_by_caller
 	      || latch_mode == BTR_SEARCH_LEAF
 	      || latch_mode == BTR_SEARCH_TREE
 	      || latch_mode == BTR_MODIFY_LEAF);
@@ -1381,7 +1374,6 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 	if (!btr_search_enabled) {
 	} else if (autoinc == 0
 	    && latch_mode <= BTR_MODIFY_LEAF
-	    && !modify_external
 # ifdef PAGE_CUR_LE_OR_EXTENDS
 	    && mode != PAGE_CUR_LE_OR_EXTENDS
 # endif /* PAGE_CUR_LE_OR_EXTENDS */
@@ -1463,16 +1455,9 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 		break;
 	default:
 		if (!srv_read_only_mode) {
-			if (s_latch_by_caller) {
-			} else if (!modify_external) {
-				/* BTR_SEARCH_TREE is intended to be used with
-				BTR_ALREADY_S_LATCHED */
+			if (!latch_by_caller) {
 				ut_ad(latch_mode != BTR_SEARCH_TREE);
-
 				mtr_s_lock_index(index, mtr);
-			} else {
-				/* BTR_MODIFY_EXTERNAL needs to be excluded */
-				mtr_sx_lock_index(index, mtr);
 			}
 			upper_rw_latch = RW_S_LATCH;
 		} else {
@@ -1540,10 +1525,9 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 			each pages should be latched before reading. */
 			if (height == ULINT_UNDEFINED
 			    && upper_rw_latch == RW_S_LATCH
-			    && (modify_external || autoinc)) {
+			    && autoinc) {
 				/* needs sx-latch of root page
-				for fseg operation or for writing
-				PAGE_ROOT_AUTO_INC */
+				for writing PAGE_ROOT_AUTO_INC */
 				rw_latch = RW_SX_LATCH;
 			} else {
 				rw_latch = upper_rw_latch;
@@ -1727,7 +1711,7 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 		is latched differently from leaf pages. */
 		ut_ad(root_leaf_rw_latch != RW_NO_LATCH);
 		ut_ad(rw_latch == RW_S_LATCH || rw_latch == RW_SX_LATCH);
-		ut_ad(rw_latch == RW_S_LATCH || modify_external || autoinc);
+		ut_ad(rw_latch == RW_S_LATCH || autoinc);
 		ut_ad(!autoinc || root_leaf_rw_latch == RW_X_LATCH);
 
 		ut_ad(n_blocks == 0);
@@ -1789,12 +1773,9 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 		case BTR_CONT_SEARCH_TREE:
 			break;
 		default:
-			if (!s_latch_by_caller
-			    && !srv_read_only_mode
-			    && !modify_external) {
+			if (!latch_by_caller
+			    && !srv_read_only_mode) {
 				/* Release the tree s-latch */
-				/* NOTE: BTR_MODIFY_EXTERNAL
-				needs to keep tree sx-latch */
 				mtr_release_s_latch_at_savepoint(
 					mtr, savepoint,
 					&index->lock);
@@ -1817,7 +1798,7 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 
 			for (; n_releases < n_blocks; n_releases++) {
 				if (n_releases == 0
-				    && (modify_external || autoinc)) {
+				    && (autoinc)) {
 					/* keep the root page latch */
 					ut_ad(mtr->memo_contains_flagged(
 						      tree_blocks[n_releases],
@@ -2355,7 +2336,7 @@ dberr_t btr_cur_search_to_nth_level(dict_index_t *index, ulint level,
 			ut_ad(mtr->memo_contains_flagged(block,
 							 upper_rw_latch));
 
-			if (s_latch_by_caller) {
+			if (latch_by_caller) {
 				ut_ad(latch_mode == BTR_SEARCH_TREE);
 				/* to exclude modifying tree operations
 				should sx-latch the index. */
@@ -2478,15 +2459,11 @@ btr_cur_open_at_index_side(
 
 	ut_ad(level != ULINT_UNDEFINED);
 
-	bool	s_latch_by_caller;
-
-	s_latch_by_caller = latch_mode & BTR_ALREADY_S_LATCHED;
+	const bool latch_by_caller = latch_mode & BTR_ALREADY_S_LATCHED;
 	latch_mode &= ulint(~BTR_ALREADY_S_LATCHED);
 
 	lock_intention = btr_cur_get_and_clear_intention(&latch_mode);
 
-	ut_ad(!(latch_mode & BTR_MODIFY_EXTERNAL));
-
 	/* This function doesn't need to lock left page of the leaf page */
 	if (latch_mode == BTR_SEARCH_PREV) {
 		latch_mode = BTR_SEARCH_LEAF;
@@ -2521,16 +2498,13 @@ btr_cur_open_at_index_side(
 		upper_rw_latch = RW_X_LATCH;
 		break;
 	default:
-		ut_ad(!s_latch_by_caller
+		ut_ad(!latch_by_caller
 		      || mtr->memo_contains_flagged(&index->lock,
 						    MTR_MEMO_SX_LOCK
 						    | MTR_MEMO_S_LOCK));
 		if (!srv_read_only_mode) {
-			if (!s_latch_by_caller) {
-				/* BTR_SEARCH_TREE is intended to be used with
-				BTR_ALREADY_S_LATCHED */
+			if (!latch_by_caller) {
 				ut_ad(latch_mode != BTR_SEARCH_TREE);
-
 				mtr_s_lock_index(index, mtr);
 			}
 			upper_rw_latch = RW_S_LATCH;
@@ -2631,7 +2605,7 @@ btr_cur_open_at_index_side(
 				if (UNIV_UNLIKELY(srv_read_only_mode)) {
 					break;
 				}
-				if (!s_latch_by_caller) {
+				if (!latch_by_caller) {
 					/* Release the tree s-latch */
 					mtr_release_s_latch_at_savepoint(
 						mtr, savepoint, &index->lock);
@@ -2649,12 +2623,12 @@ btr_cur_open_at_index_side(
 			   && UNIV_LIKELY(!srv_read_only_mode)) {
 			/* We already have the block latched. */
 			ut_ad(latch_mode == BTR_SEARCH_TREE);
-			ut_ad(s_latch_by_caller);
+			ut_ad(latch_by_caller);
 			ut_ad(upper_rw_latch == RW_S_LATCH);
 			ut_ad(mtr->memo_contains_flagged(block,
 							 MTR_MEMO_PAGE_S_FIX));
 
-			if (s_latch_by_caller) {
+			if (latch_by_caller) {
 				/* to exclude modifying tree operations
 				should sx-latch the index. */
 				ut_ad(mtr->memo_contains(index->lock,
@@ -2808,8 +2782,6 @@ btr_cur_open_at_rnd_pos(
 
 	lock_intention = btr_cur_get_and_clear_intention(&latch_mode);
 
-	ut_ad(!(latch_mode & BTR_MODIFY_EXTERNAL));
-
 	ulint savepoint = mtr_set_savepoint(mtr);
 
 	rw_lock_type_t upper_rw_latch;
@@ -6824,8 +6796,9 @@ struct btr_blob_log_check_t {
 				+ offs;
 		} else {
 			ut_ad(m_pcur->rel_pos == BTR_PCUR_ON);
+			mtr_sx_lock_index(index, m_mtr);
 			ut_a(m_pcur->restore_position(
-			      BTR_MODIFY_LEAF | BTR_MODIFY_EXTERNAL,
+			      BTR_MODIFY_LEAF_ALREADY_LATCHED,
 			      m_mtr) == btr_pcur_t::SAME_ALL);
 		}
 

storage/innobase/include/btr0btr.h

@@ -103,8 +103,8 @@ enum btr_latch_mode {
 	BTR_SEARCH_TREE_ALREADY_S_LATCHED = BTR_SEARCH_TREE
 	| BTR_ALREADY_S_LATCHED,
 	/** Search and X-latch a leaf page, assuming that the
-	dict_index_t::lock S-latch is being held. */
-	BTR_MODIFY_LEAF_ALREADY_S_LATCHED = BTR_MODIFY_LEAF
+	dict_index_t::lock is being held in non-exclusive mode. */
+	BTR_MODIFY_LEAF_ALREADY_LATCHED = BTR_MODIFY_LEAF
 	| BTR_ALREADY_S_LATCHED,
 
 	/** Attempt to delete-mark a secondary index record. */
@@ -146,10 +146,6 @@ the insert buffer to speed up inserts */
 to find proper rec to undo insert.*/
 #define BTR_RTREE_UNDO_INS	4096U
 
-/** In the case of BTR_MODIFY_LEAF, the caller intends to allocate or
-free the pages of externally stored fields. */
-#define BTR_MODIFY_EXTERNAL	16384U
-
 /** Try to delete mark the record at the searched position when the
 record is in spatial index */
 #define BTR_RTREE_DELETE_MARK	16384U
@@ -163,13 +159,11 @@ record is in spatial index */
 				| BTR_IGNORE_SEC_UNIQUE		\
 				| BTR_ALREADY_S_LATCHED		\
 				| BTR_LATCH_FOR_INSERT		\
-				| BTR_LATCH_FOR_DELETE		\
-				| BTR_MODIFY_EXTERNAL)))
+				| BTR_LATCH_FOR_DELETE)))
 
 #define BTR_LATCH_MODE_WITHOUT_INTENTION(latch_mode)		\
 	((latch_mode) & ulint(~(BTR_LATCH_FOR_INSERT		\
-				| BTR_LATCH_FOR_DELETE		\
-				| BTR_MODIFY_EXTERNAL)))
+				| BTR_LATCH_FOR_DELETE)))
 
 /**************************************************************//**
 Checks and adjusts the root node of a tree during IMPORT TABLESPACE.

storage/innobase/row/row0ins.cc

@@ -2574,7 +2574,7 @@ row_ins_clust_index_entry_low(
 		} else {
 			if (mode == BTR_MODIFY_LEAF
 			    && dict_index_is_online_ddl(index)) {
-				mode = BTR_MODIFY_LEAF_ALREADY_S_LATCHED;
+				mode = BTR_MODIFY_LEAF_ALREADY_LATCHED;
 				mtr_s_lock_index(index, &mtr);
 			}