Bug#12861864 RACE CONDITION IN BTR_GET_SIZE() AND DROP INDEX/TABLE/DATABASE

also filed as Bug#13146269, Bug#13713178

btr_get_size(): Add mtr_t parameter. Require that the caller S-latches
index->lock. If index->page==FIL_NULL or the index is to be dropped,
return ULINT_UNDEFINED to indicate that the statistics are
unavailable.

dict_update_statistics(): If btr_get_size() returns ULINT_UNDEFINED,
fake the index cardinality statistics.

dict_index_set_page(): Unused function, remove.

row_drop_table_for_mysql(): Before starting to drop the table, mark
the indexes unavailable in the data dictionary cache while holding
index->lock X-latch.

ha_innobase::prepare_drop_index(), ha_innobase::final_drop_index():
When setting index->to_be_dropped, acquire the index->lock X-latch.

rb:960 approved by Jimmy Yang

storage/innodb_plugin/ChangeLog

+2012-02-28	The InnoDB Team
+
+	* btr/btr0btr.c, dict/dict0dict.c, include/btr0btr.h,
+	include/dict0dict.h, include/dict0dict.ic, include/dict0mem.h,
+	handler/handler0alter.cc, row/row0mysql.c:
+	Fix Bug#12861864 RACE CONDITION IN BTR_GET_SIZE() AND
+	DROP INDEX/TABLE/DATABASE
+
 2012-02-15	The InnoDB Team
 
 	* btr/btr0btr.c, btr/btr0cur.c, fsp/fsp0fsp.c, ibuf/ibuf0ibuf.c,

storage/innodb_plugin/btr/btr0btr.c

@@ -991,45 +991,49 @@ btr_page_alloc(
 
 /**************************************************************//**
 Gets the number of pages in a B-tree.
-@return	number of pages */
+@return	number of pages, or ULINT_UNDEFINED if the index is unavailable */
 UNIV_INTERN
 ulint
 btr_get_size(
 /*=========*/
 	dict_index_t*	index,	/*!< in: index */
-	ulint		flag)	/*!< in: BTR_N_LEAF_PAGES or BTR_TOTAL_SIZE */
+	ulint		flag,	/*!< in: BTR_N_LEAF_PAGES or BTR_TOTAL_SIZE */
+	mtr_t*		mtr)	/*!< in/out: mini-transaction where index
+				is s-latched */
 {
 	fseg_header_t*	seg_header;
 	page_t*		root;
 	ulint		n;
 	ulint		dummy;
-	mtr_t		mtr;
 
-	mtr_start(&mtr);
+	ut_ad(mtr_memo_contains(mtr, dict_index_get_lock(index),
+				MTR_MEMO_S_LOCK));
 
-	mtr_s_lock(dict_index_get_lock(index), &mtr);
+	if (index->page == FIL_NULL
+	    || index->to_be_dropped
+	    || *index->name == TEMP_INDEX_PREFIX) {
+		return(ULINT_UNDEFINED);
+	}
 
-	root = btr_root_get(index, &mtr);
+	root = btr_root_get(index, mtr);
 
 	if (flag == BTR_N_LEAF_PAGES) {
 		seg_header = root + PAGE_HEADER + PAGE_BTR_SEG_LEAF;
 
-		fseg_n_reserved_pages(seg_header, &n, &mtr);
+		fseg_n_reserved_pages(seg_header, &n, mtr);
 
 	} else if (flag == BTR_TOTAL_SIZE) {
 		seg_header = root + PAGE_HEADER + PAGE_BTR_SEG_TOP;
 
-		n = fseg_n_reserved_pages(seg_header, &dummy, &mtr);
+		n = fseg_n_reserved_pages(seg_header, &dummy, mtr);
 
 		seg_header = root + PAGE_HEADER + PAGE_BTR_SEG_LEAF;
 
-		n += fseg_n_reserved_pages(seg_header, &dummy, &mtr);
+		n += fseg_n_reserved_pages(seg_header, &dummy, mtr);
 	} else {
 		ut_error;
 	}
 
-	mtr_commit(&mtr);
-
 	return(n);
 }
 

storage/innodb_plugin/dict/dict0dict.c

@@ -4267,16 +4267,27 @@ dict_update_statistics(
 		    (srv_force_recovery < SRV_FORCE_NO_IBUF_MERGE
 		     || (srv_force_recovery < SRV_FORCE_NO_LOG_REDO
 			 && dict_index_is_clust(index)))) {
+			mtr_t	mtr;
 			ulint	size;
-			size = btr_get_size(index, BTR_TOTAL_SIZE);
 
-			index->stat_index_size = size;
+			mtr_start(&mtr);
+			mtr_s_lock(dict_index_get_lock(index), &mtr);
 
-			sum_of_index_sizes += size;
+			size = btr_get_size(index, BTR_TOTAL_SIZE, &mtr);
 
-			size = btr_get_size(index, BTR_N_LEAF_PAGES);
+			if (size != ULINT_UNDEFINED) {
+				sum_of_index_sizes += size;
+				index->stat_index_size = size;
+				size = btr_get_size(
+					index, BTR_N_LEAF_PAGES, &mtr);
+			}
+
+			mtr_commit(&mtr);
 
-			if (size == 0) {
+			switch (size) {
+			case ULINT_UNDEFINED:
+				goto fake_statistics;
+			case 0:
 				/* The root node of the tree is a leaf */
 				size = 1;
 			}
@@ -4293,6 +4304,7 @@ dict_update_statistics(
 			various means, also via secondary indexes. */
 			ulint	i;
 
+fake_statistics:
 			sum_of_index_sizes++;
 			index->stat_index_size = index->stat_n_leaf_pages = 1;
 

storage/innodb_plugin/handler/handler0alter.cc

 /*****************************************************************************
 
-Copyright (c) 2005, 2010, Innobase Oy. All Rights Reserved.
+Copyright (c) 2005, 2012, Oracle and/or its affiliates. All Rights Reserved.
 
 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
@@ -11,8 +11,8 @@ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
 
 *****************************************************************************/
 
@@ -1010,7 +1010,9 @@ ha_innobase::prepare_drop_index(
 			goto func_exit;
 		}
 
+		rw_lock_x_lock(dict_index_get_lock(index));
 		index->to_be_dropped = TRUE;
+		rw_lock_x_unlock(dict_index_get_lock(index));
 	}
 
 	/* If FOREIGN_KEY_CHECKS = 1 you may not drop an index defined
@@ -1129,7 +1131,9 @@ ha_innobase::prepare_drop_index(
 			= dict_table_get_first_index(prebuilt->table);
 
 		do {
+			rw_lock_x_lock(dict_index_get_lock(index));
 			index->to_be_dropped = FALSE;
+			rw_lock_x_unlock(dict_index_get_lock(index));
 			index = dict_table_get_next_index(index);
 		} while (index);
 	}
@@ -1189,7 +1193,9 @@ ha_innobase::final_drop_index(
 		for (index = dict_table_get_first_index(prebuilt->table);
 		     index; index = dict_table_get_next_index(index)) {
 
+			rw_lock_x_lock(dict_index_get_lock(index));
 			index->to_be_dropped = FALSE;
+			rw_lock_x_unlock(dict_index_get_lock(index));
 		}
 
 		goto func_exit;

storage/innodb_plugin/include/btr0btr.h

@@ -536,13 +536,16 @@ btr_parse_page_reorganize(
 #ifndef UNIV_HOTBACKUP
 /**************************************************************//**
 Gets the number of pages in a B-tree.
-@return	number of pages */
+@return	number of pages, or ULINT_UNDEFINED if the index is unavailable */
 UNIV_INTERN
 ulint
 btr_get_size(
 /*=========*/
 	dict_index_t*	index,	/*!< in: index */
-	ulint		flag);	/*!< in: BTR_N_LEAF_PAGES or BTR_TOTAL_SIZE */
+	ulint		flag,	/*!< in: BTR_N_LEAF_PAGES or BTR_TOTAL_SIZE */
+	mtr_t*		mtr)	/*!< in/out: mini-transaction where index
+				is s-latched */
+	__attribute__((nonnull, warn_unused_result));
 /**************************************************************//**
 Allocates a new file page to be used in an index tree. NOTE: we assume
 that the caller has made the reservation for free extents!

storage/innodb_plugin/include/dict0dict.h

 /*****************************************************************************
 
-Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
 
 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
@@ -11,8 +11,8 @@ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
 
 *****************************************************************************/
 
@@ -1018,14 +1018,6 @@ dict_index_get_page(
 /*================*/
 	const dict_index_t*	tree);	/*!< in: index */
 /*********************************************************************//**
-Sets the page number of the root of index tree. */
-UNIV_INLINE
-void
-dict_index_set_page(
-/*================*/
-	dict_index_t*	index,	/*!< in/out: index */
-	ulint		page);	/*!< in: page number */
-/*********************************************************************//**
 Gets the read-write lock of the index tree.
 @return	read-write lock */
 UNIV_INLINE

storage/innodb_plugin/include/dict0dict.ic

 /*****************************************************************************
 
-Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
 
 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
@@ -11,8 +11,8 @@ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
 
 *****************************************************************************/
 
@@ -722,21 +722,6 @@ dict_index_get_page(
 	return(index->page);
 }
 
-/*********************************************************************//**
-Sets the page number of the root of index tree. */
-UNIV_INLINE
-void
-dict_index_set_page(
-/*================*/
-	dict_index_t*	index,	/*!< in/out: index */
-	ulint		page)	/*!< in: page number */
-{
-	ut_ad(index);
-	ut_ad(index->magic_n == DICT_INDEX_MAGIC_N);
-
-	index->page = page;
-}
-
 /*********************************************************************//**
 Gets the read-write lock of the index tree.
 @return	read-write lock */

storage/innodb_plugin/include/dict0mem.h

 /*****************************************************************************
 
-Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.
+Copyright (c) 1996, 2012, Oracle and/or its affiliates. All Rights Reserved.
 
 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
@@ -11,8 +11,8 @@ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
 
 *****************************************************************************/
 
@@ -305,7 +305,9 @@ struct dict_index_struct{
 	unsigned	to_be_dropped:1;
 				/*!< TRUE if this index is marked to be
 				dropped in ha_innobase::prepare_drop_index(),
-				otherwise FALSE */
+				otherwise FALSE. Protected by
+				dict_sys->mutex, dict_operation_lock and
+				index->lock.*/
 	dict_field_t*	fields;	/*!< array of field descriptions */
 #ifndef UNIV_HOTBACKUP
 	UT_LIST_NODE_T(dict_index_t)

storage/innodb_plugin/row/row0mysql.c

 /*****************************************************************************
 
-Copyright (c) 2000, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2000, 2012, Oracle and/or its affiliates. All Rights Reserved.
 
 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
@@ -11,8 +11,8 @@ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along with
-this program; if not, write to the Free Software Foundation, Inc., 59 Temple
-Place, Suite 330, Boston, MA 02111-1307 USA
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
 
 *****************************************************************************/
 
@@ -3013,6 +3013,7 @@ row_drop_table_for_mysql(
 {
 	dict_foreign_t*	foreign;
 	dict_table_t*	table;
+	dict_index_t*	index;
 	ulint		space_id;
 	ulint		err;
 	const char*	table_name;
@@ -3305,6 +3306,18 @@ row_drop_table_for_mysql(
 			   "END;\n"
 			   , FALSE, trx);
 
+	/* Mark all indexes unavailable in the data dictionary cache
+	before starting to drop the table. */
+
+	for (index = dict_table_get_first_index(table);
+	     index != NULL;
+	     index = dict_table_get_next_index(index)) {
+		rw_lock_x_lock(dict_index_get_lock(index));
+		ut_ad(!index->to_be_dropped);
+		index->to_be_dropped = TRUE;
+		rw_lock_x_unlock(dict_index_get_lock(index));
+	}
+
 	switch (err) {
 		ibool		is_temp;
 		const char*	name_or_path;
@@ -3384,6 +3397,17 @@ row_drop_table_for_mysql(
 		the undo log. We can directly exit here
 		and return the DB_TOO_MANY_CONCURRENT_TRXS
 		error. */
+
+		/* Mark all indexes available in the data dictionary
+		cache again. */
+
+		for (index = dict_table_get_first_index(table);
+		     index != NULL;
+		     index = dict_table_get_next_index(index)) {
+			rw_lock_x_lock(dict_index_get_lock(index));
+			index->to_be_dropped = FALSE;
+			rw_lock_x_unlock(dict_index_get_lock(index));
+		}
 		break;
 
 	case DB_OUT_OF_FILE_SPACE: