MDEV-11799 InnoDB can abort if the doublewrite buffer

contains a bad and a good copy

Clean up the InnoDB doublewrite buffer code.

buf_dblwr_init_or_load_pages(): Do not add empty pages to the buffer.

buf_dblwr_process(): Do consider changes to pages that are all zero.
Do not abort when finding a corrupted copy of a page in the doublewrite
buffer, because there could be multiple copies in the doublewrite buffer,
and only one of them needs to be good.

mysql-test/suite/innodb/r/group_commit_crash.result

@@ -1,4 +1,3 @@
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 CREATE TABLE t1(a CHAR(255),
 b CHAR(255),
 c CHAR(255),

mysql-test/suite/innodb/r/group_commit_crash_no_optimize_thread.result

@@ -1,4 +1,3 @@
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 CREATE TABLE t1(a CHAR(255),
 b CHAR(255),
 c CHAR(255),

mysql-test/suite/innodb/r/innodb-alter-tempfile.result

@@ -4,10 +4,6 @@
 # Temporary tablename will be unique. This makes sure that future
 # in-place ALTERs of the same table will not be blocked due to
 # temporary tablename.
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed
-");
-call mtr.add_suppression("InnoDB: file read of space .* page .*");
-call mtr.add_suppression("InnoDB: Trying to recover it from the doublewrite buffer.");
 # Crash the server in ha_innobase::commit_inplace_alter_table()
 CREATE TABLE t1 (f1 INT NOT NULL, f2 INT NOT NULL) ENGINE=innodb;
 SET debug='d,innodb_alter_commit_crash_before_commit';

mysql-test/suite/innodb/r/innodb_bug14147491.result

@@ -1,6 +1,5 @@
 call mtr.add_suppression("InnoDB: Database page corruption on disk or a failed.*");
 CALL mtr.add_suppression("InnoDB: Error: Unable to read tablespace .* page no .* into the buffer pool after 100 attempts");
-CALL mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 CALL mtr.add_suppression("InnoDB: Database page corruption on disk or a failed");
 CALL mtr.add_suppression("InnoDB: Space .* file test/t1 read of page .*");
 CALL mtr.add_suppression("InnoDB: You may have to recover from a backup.");

mysql-test/suite/innodb/r/xa_recovery.result

@@ -1,4 +1,3 @@
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 CREATE TABLE t1 (a INT) ENGINE=InnoDB;
 INSERT INTO t1 VALUES (1);
 XA START 'x';
@@ -6,6 +5,7 @@ UPDATE t1 set a=2;
 XA END 'x';
 XA PREPARE 'x';
 call mtr.add_suppression("Found 1 prepared XA transactions");
+# Kill the server
 SELECT * FROM t1 LOCK IN SHARE MODE;
 SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
 SELECT * FROM t1;

mysql-test/suite/innodb/t/group_commit_crash.test

@@ -9,8 +9,6 @@
 --source include/have_debug.inc
 --source include/have_log_bin.inc
 
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
-
 let $file_format_max=`SELECT @@innodb_file_format_max`;
 CREATE TABLE t1(a CHAR(255),
                 b CHAR(255),

mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test

@@ -9,8 +9,6 @@
 --source include/have_debug.inc
 --source include/have_log_bin.inc
 
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
-
 let $file_format_max=`SELECT @@innodb_file_format_max`;
 CREATE TABLE t1(a CHAR(255),
                 b CHAR(255),

mysql-test/suite/innodb/t/innodb-alter-tempfile.test

@@ -20,13 +20,6 @@
 --echo # in-place ALTERs of the same table will not be blocked due to
 --echo # temporary tablename.
 
-# As we intentionally crash below, there could be partially written
-# pages that are then recovered from the doublewrite buffer
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed
-");
-call mtr.add_suppression("InnoDB: file read of space .* page .*");
-call mtr.add_suppression("InnoDB: Trying to recover it from the doublewrite buffer.");
-
 let datadir= `select @@datadir`;
 
 --let $_server_id= `SELECT @@server_id`

mysql-test/suite/innodb/t/innodb_bug14147491.test

@@ -21,7 +21,6 @@ source include/have_debug.inc;
 source include/not_windows.inc;
 
 CALL mtr.add_suppression("InnoDB: Error: Unable to read tablespace .* page no .* into the buffer pool after 100 attempts");
-CALL mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 CALL mtr.add_suppression("InnoDB: Database page corruption on disk or a failed");
 CALL mtr.add_suppression("InnoDB: Space .* file test/t1 read of page .*");
 CALL mtr.add_suppression("InnoDB: You may have to recover from a backup.");

mysql-test/suite/innodb/t/xa_recovery.test

@@ -12,11 +12,6 @@ if (`select plugin_auth_version <= "5.6.24" from information_schema.plugins wher
 FLUSH TABLES;
 --enable_query_log
 
-#
-# We kill server belown with timeout 0 that is not fully safe
-#
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
-
 CREATE TABLE t1 (a INT) ENGINE=InnoDB;
 INSERT INTO t1 VALUES (1);
 connect (con1,localhost,root);
@@ -25,15 +20,8 @@ connection default;
 
 call mtr.add_suppression("Found 1 prepared XA transactions");
 
-# Kill and restart the server.
+--source include/kill_mysqld.inc
--- exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+--source include/start_mysqld.inc
--- shutdown_server 0
--- source include/wait_until_disconnected.inc
-
--- exec echo "restart" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
--- enable_reconnect
--- source include/wait_until_connected_again.inc
--- disable_reconnect
 
 disconnect con1;
 connect (con1,localhost,root);

mysql-test/suite/rpl/r/rpl_gtid_crash.result

@@ -3,7 +3,6 @@ include/rpl_init.inc [topology=1->2]
 call mtr.add_suppression("Checking table:");
 call mtr.add_suppression("client is using or hasn't closed the table properly");
 call mtr.add_suppression("Table .* is marked as crashed and should be repaired");
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 flush tables;
 ALTER TABLE mysql.gtid_slave_pos ENGINE=InnoDB;
 CREATE TABLE t1 (a INT PRIMARY KEY, b INT) ENGINE=InnoDB;

mysql-test/suite/rpl/t/rpl_gtid_crash.test

@@ -12,11 +12,6 @@
 call mtr.add_suppression("Checking table:");
 call mtr.add_suppression("client is using or hasn't closed the table properly");
 call mtr.add_suppression("Table .* is marked as crashed and should be repaired");
-# We have seen this warning a couple of times in Buildbot. Since we crash the
-# server deliberately, it seems possible that we could in rare cases crash in
-# the middle of a page write. The page is recovered from the doublewrite
-# buffer ("[Note] InnoDB: Recovered the page from the doublewrite buffer.").
-call mtr.add_suppression("InnoDB: Warning: database page corruption or a failed");
 flush tables;
 
 ALTER TABLE mysql.gtid_slave_pos ENGINE=InnoDB;

storage/innobase/buf/buf0dblwr.cc

@@ -455,8 +455,11 @@ buf_dblwr_init_or_load_pages(
 			os_file_write(path, file, page,
 				      source_page_no * UNIV_PAGE_SIZE,
 				      UNIV_PAGE_SIZE);
-		} else if (load_corrupt_pages) {
+		} else if (load_corrupt_pages
-
+			   && !buf_page_is_zeroes(page, FIL_PAGE_DATA)) {
+			/* Each valid page header must contain some
+			nonzero bytes, such as FIL_PAGE_OFFSET
+			or FIL_PAGE_LSN. */
 			recv_dblwr.add(page);
 		}
 
@@ -492,8 +495,6 @@ buf_dblwr_process()
 
 	for (std::list<byte*>::iterator i = recv_dblwr.pages.begin();
 	     i != recv_dblwr.pages.end(); ++i, ++page_no_dblwr ) {
-		bool is_compressed = false;
-
 		page = *i;
 		page_no  = mach_read_from_4(page + FIL_PAGE_OFFSET);
 		space_id = mach_read_from_4(page + FIL_PAGE_SPACE_ID);
@@ -501,139 +502,104 @@ buf_dblwr_process()
 		if (!fil_tablespace_exists_in_mem(space_id)) {
 			/* Maybe we have dropped the single-table tablespace
 			and this page once belonged to it: do nothing */
-
+			continue;
-		} else if (!fil_check_adress_in_tablespace(space_id,
-							   page_no)) {
-			ib_logf(IB_LOG_LEVEL_WARN,
-				"A page in the doublewrite buffer is not "
-				"within space bounds; space id %lu "
-				"page number %lu, page %lu in "
-				"doublewrite buf.",
-				(ulong) space_id, (ulong) page_no,
-				page_no_dblwr);
-		} else {
-			ulint	zip_size = fil_space_get_zip_size(space_id);
-
-			/* Read in the actual page from the file */
-			fil_io(OS_FILE_READ,
-				true,
-				space_id,
-				zip_size,
-				page_no,
-				0,
-				zip_size ? zip_size : UNIV_PAGE_SIZE,
-				read_buf,
-				NULL,
-				0);
-
-			/* Is page compressed ? */
-			is_compressed = fil_page_is_compressed_encrypted(read_buf) |
-				fil_page_is_compressed(read_buf);
-
-			/* If page was compressed, decompress it before we
-			check checksum. */
-			if (is_compressed) {
-				fil_decompress_page(NULL, read_buf, UNIV_PAGE_SIZE, NULL, true);
-			}
-
-			if (fil_space_verify_crypt_checksum(read_buf, zip_size)) {
-				/* page is encrypted and checksum is OK */
-			} else if (buf_page_is_corrupted(true, read_buf, zip_size)) {
-
-				fprintf(stderr,
-					"InnoDB: Warning: database page"
-					" corruption or a failed\n"
-					"InnoDB: file read of"
-					" space %lu page %lu.\n"
-					"InnoDB: Trying to recover it from"
-					" the doublewrite buffer.\n",
-					(ulong) space_id, (ulong) page_no);
-
-				/* Is page compressed ? */
-				is_compressed = fil_page_is_compressed_encrypted(page) |
-					fil_page_is_compressed(page);
-
-				/* If page was compressed, decompress it before we
-				check checksum. */
-				if (is_compressed) {
-					fil_decompress_page(NULL, page, UNIV_PAGE_SIZE, NULL, true);
-				}
-
-				if (fil_space_verify_crypt_checksum(page, zip_size)) {
-					/* the doublewrite buffer page is encrypted and OK */
-				} else if (buf_page_is_corrupted(true,
-								 page,
-								 zip_size)) {
-					fprintf(stderr,
-						"InnoDB: Dump of the page:\n");
-					buf_page_print(
-						read_buf, zip_size,
-						BUF_PAGE_PRINT_NO_CRASH);
-					fprintf(stderr,
-						"InnoDB: Dump of"
-						" corresponding page"
-						" in doublewrite buffer:\n");
-					buf_page_print(
-						page, zip_size,
-						BUF_PAGE_PRINT_NO_CRASH);
-
-					fprintf(stderr,
-						"InnoDB: Also the page in the"
-						" doublewrite buffer"
-						" is corrupt.\n"
-						"InnoDB: Cannot continue"
-						" operation.\n"
-						"InnoDB: You can try to"
-						" recover the database"
-						" with the my.cnf\n"
-						"InnoDB: option:\n"
-						"InnoDB:"
-						" innodb_force_recovery=6\n");
-					ut_error;
-				}
-
-				/* Write the good page from the
-				doublewrite buffer to the intended
-				position */
-
-				fil_io(OS_FILE_WRITE,
-					true,
-					space_id,
-					zip_size,
-					page_no,
-					0,
-					zip_size ? zip_size : UNIV_PAGE_SIZE,
-					page,
-					NULL,
-					0);
-
-				ib_logf(IB_LOG_LEVEL_INFO,
-					"Recovered the page from"
-					" the doublewrite buffer.");
-
-			} else if (buf_page_is_zeroes(read_buf, zip_size)) {
-
-				if (!buf_page_is_zeroes(page, zip_size)
-				    && !buf_page_is_corrupted(true, page,
-							      zip_size)) {
-
-					/* Database page contained only
-					zeroes, while a valid copy is
-					available in dblwr buffer. */
-
-					fil_io(OS_FILE_WRITE,
-						true,
-						space_id,
-						zip_size,
-						page_no,
-						0,
-						zip_size ? zip_size : UNIV_PAGE_SIZE,
-						page,
-						NULL,
-						0);
-				}
-			}
 		}
+
+		if (!fil_check_adress_in_tablespace(space_id, page_no)) {
+			ib_logf(IB_LOG_LEVEL_WARN,
+				"A copy of page " ULINTPF ":" ULINTPF
+				" in the doublewrite buffer slot " ULINTPF
+				" is not within space bounds",
+				space_id, page_no, page_no_dblwr);
+			continue;
+		}
+
+		ulint	zip_size = fil_space_get_zip_size(space_id);
+		ut_ad(!buf_page_is_zeroes(page, zip_size));
+
+		/* Read in the actual page from the file */
+		fil_io(OS_FILE_READ,
+		       true,
+		       space_id,
+		       zip_size,
+		       page_no,
+		       0,
+		       zip_size ? zip_size : UNIV_PAGE_SIZE,
+		       read_buf,
+		       NULL,
+		       0);
+
+		const bool is_all_zero = buf_page_is_zeroes(
+			read_buf, zip_size);
+
+		if (is_all_zero) {
+			/* We will check if the copy in the
+			doublewrite buffer is valid. If not, we will
+			ignore this page (there should be redo log
+			records to initialize it). */
+		} else {
+			if (fil_page_is_compressed_encrypted(read_buf) ||
+			    fil_page_is_compressed(read_buf)) {
+				/* Decompress the page before
+				validating the checksum. */
+				fil_decompress_page(
+					NULL, read_buf, UNIV_PAGE_SIZE,
+					NULL, true);
+			}
+
+			if (fil_space_verify_crypt_checksum(
+				   read_buf, zip_size)
+			   || !buf_page_is_corrupted(
+				   true, read_buf, zip_size)) {
+				/* The page is good; there is no need
+				to consult the doublewrite buffer. */
+				continue;
+			}
+
+			/* We intentionally skip this message for
+			is_all_zero pages. */
+			ib_logf(IB_LOG_LEVEL_INFO,
+				"Trying to recover page " ULINTPF ":" ULINTPF
+				" from the doublewrite buffer.",
+				space_id, page_no);
+		}
+
+		/* Next, validate the doublewrite page. */
+		if (fil_page_is_compressed_encrypted(page) ||
+		    fil_page_is_compressed(page)) {
+			/* Decompress the page before
+			validating the checksum. */
+			fil_decompress_page(
+				NULL, page, UNIV_PAGE_SIZE, NULL, true);
+		}
+
+		if (!fil_space_verify_crypt_checksum(page, zip_size)
+		    && buf_page_is_corrupted(true, page, zip_size)) {
+			if (!is_all_zero) {
+				ib_logf(IB_LOG_LEVEL_WARN,
+					"A doublewrite copy of page "
+					ULINTPF ":" ULINTPF " is corrupted.",
+					space_id, page_no);
+			}
+			/* Theoretically we could have another good
+			copy for this page in the doublewrite
+			buffer. If not, we will report a fatal error
+			for a corrupted page somewhere else if that
+			page was truly needed. */
+			continue;
+		}
+
+		/* Write the good page from the doublewrite buffer to
+		the intended position. */
+
+		fil_io(OS_FILE_WRITE, true, space_id, zip_size, page_no, 0,
+		       zip_size ? zip_size : UNIV_PAGE_SIZE,
+		       page, NULL, 0);
+
+		ib_logf(IB_LOG_LEVEL_INFO,
+			"Recovered page " ULINTPF ":" ULINTPF " from"
+			" the doublewrite buffer.",
+			space_id, page_no);
 	}
 
 	ut_free(unaligned_read_buf);

storage/xtradb/buf/buf0dblwr.cc

@@ -455,8 +455,11 @@ buf_dblwr_init_or_load_pages(
 			os_file_write(path, file, page,
 				      source_page_no * UNIV_PAGE_SIZE,
 				      UNIV_PAGE_SIZE);
-		} else if (load_corrupt_pages) {
+		} else if (load_corrupt_pages
-
+			   && !buf_page_is_zeroes(page, FIL_PAGE_DATA)) {
+			/* Each valid page header must contain some
+			nonzero bytes, such as FIL_PAGE_OFFSET
+			or FIL_PAGE_LSN. */
 			recv_dblwr.add(page);
 		}
 
@@ -492,8 +495,6 @@ buf_dblwr_process()
 
 	for (std::list<byte*>::iterator i = recv_dblwr.pages.begin();
 	     i != recv_dblwr.pages.end(); ++i, ++page_no_dblwr ) {
-		bool is_compressed = false;
-
 		page = *i;
 		page_no  = mach_read_from_4(page + FIL_PAGE_OFFSET);
 		space_id = mach_read_from_4(page + FIL_PAGE_SPACE_ID);
@@ -501,138 +502,104 @@ buf_dblwr_process()
 		if (!fil_tablespace_exists_in_mem(space_id)) {
 			/* Maybe we have dropped the single-table tablespace
 			and this page once belonged to it: do nothing */
-
+			continue;
-		} else if (!fil_check_adress_in_tablespace(space_id,
-							   page_no)) {
-			ib_logf(IB_LOG_LEVEL_WARN,
-				"A page in the doublewrite buffer is not "
-				"within space bounds; space id %lu "
-				"page number %lu, page %lu in "
-				"doublewrite buf.",
-				(ulong) space_id, (ulong) page_no,
-				page_no_dblwr);
-		} else {
-			ulint	zip_size = fil_space_get_zip_size(space_id);
-
-			/* Read in the actual page from the file */
-			fil_io(OS_FILE_READ,
-				true,
-				space_id,
-				zip_size,
-				page_no,
-				0,
-				zip_size ? zip_size : UNIV_PAGE_SIZE,
-				read_buf,
-				NULL,
-				0);
-
-			/* Is page compressed ? */
-			is_compressed = fil_page_is_compressed_encrypted(read_buf) |
-				fil_page_is_compressed(read_buf);
-
-			/* If page was compressed, decompress it before we
-			check checksum. */
-			if (is_compressed) {
-				fil_decompress_page(NULL, read_buf, UNIV_PAGE_SIZE, NULL, true);
-			}
-
-			if (fil_space_verify_crypt_checksum(read_buf, zip_size)) {
-				/* page is encrypted and checksum is OK */
-			} else if (buf_page_is_corrupted(true, read_buf, zip_size)) {
-
-				fprintf(stderr,
-					"InnoDB: Database page"
-					" corruption or a failed\n"
-					"InnoDB: file read of"
-					" space %lu page %lu.\n"
-					"InnoDB: Trying to recover it from"
-					" the doublewrite buffer.\n",
-					(ulong) space_id, (ulong) page_no);
-
-				/* Is page compressed ? */
-				is_compressed = fil_page_is_compressed_encrypted(page) |
-					fil_page_is_compressed(page);
-
-				/* If page was compressed, decompress it before we
-				check checksum. */
-				if (is_compressed) {
-					fil_decompress_page(NULL, page, UNIV_PAGE_SIZE, NULL, true);
-				}
-
-				if (fil_space_verify_crypt_checksum(page, zip_size)) {
-					/* the doublewrite buffer page is encrypted and OK */
-				} else if (buf_page_is_corrupted(true,
-								 page,
-								 zip_size)) {
-					fprintf(stderr,
-						"InnoDB: Dump of the page:\n");
-					buf_page_print(
-						read_buf, zip_size,
-						BUF_PAGE_PRINT_NO_CRASH);
-					fprintf(stderr,
-						"InnoDB: Dump of"
-						" corresponding page"
-						" in doublewrite buffer:\n");
-					buf_page_print(
-						page, zip_size,
-						BUF_PAGE_PRINT_NO_CRASH);
-
-					fprintf(stderr,
-						"InnoDB: Also the page in the"
-						" doublewrite buffer"
-						" is corrupt.\n"
-						"InnoDB: Cannot continue"
-						" operation.\n"
-						"InnoDB: You can try to"
-						" recover the database"
-						" with the my.cnf\n"
-						"InnoDB: option:\n"
-						"InnoDB:"
-						" innodb_force_recovery=6\n");
-					ut_error;
-				}
-
-				/* Write the good page from the
-				doublewrite buffer to the intended
-				position */
-
-				fil_io(OS_FILE_WRITE,
-					true,
-					space_id,
-					zip_size,
-					page_no,
-					0,
-					zip_size ? zip_size : UNIV_PAGE_SIZE,
-					page,
-					NULL,
-					0);
-
-				ib_logf(IB_LOG_LEVEL_INFO,
-					"Recovered the page from"
-					" the doublewrite buffer.");
-
-			} else if (buf_page_is_zeroes(read_buf, zip_size)) {
-
-				if (!buf_page_is_zeroes(page, zip_size)
-				    && !buf_page_is_corrupted(true, page,
-							      zip_size)) {
-
-					/* Database page contained only
-					zeroes, while a valid copy is
-					available in dblwr buffer. */
-
-					fil_io(OS_FILE_WRITE,
-						true,
-						space_id,
-						zip_size,
-						page_no, 0,
-						zip_size ? zip_size : UNIV_PAGE_SIZE,
-						page,
-						NULL,
-						0);
-				}
-			}
 		}
+
+		if (!fil_check_adress_in_tablespace(space_id, page_no)) {
+			ib_logf(IB_LOG_LEVEL_WARN,
+				"A copy of page " ULINTPF ":" ULINTPF
+				" in the doublewrite buffer slot " ULINTPF
+				" is not within space bounds",
+				space_id, page_no, page_no_dblwr);
+			continue;
+		}
+
+		ulint	zip_size = fil_space_get_zip_size(space_id);
+		ut_ad(!buf_page_is_zeroes(page, zip_size));
+
+		/* Read in the actual page from the file */
+		fil_io(OS_FILE_READ,
+		       true,
+		       space_id,
+		       zip_size,
+		       page_no,
+		       0,
+		       zip_size ? zip_size : UNIV_PAGE_SIZE,
+		       read_buf,
+		       NULL,
+		       0);
+
+		const bool is_all_zero = buf_page_is_zeroes(
+			read_buf, zip_size);
+
+		if (is_all_zero) {
+			/* We will check if the copy in the
+			doublewrite buffer is valid. If not, we will
+			ignore this page (there should be redo log
+			records to initialize it). */
+		} else {
+			if (fil_page_is_compressed_encrypted(read_buf) ||
+			    fil_page_is_compressed(read_buf)) {
+				/* Decompress the page before
+				validating the checksum. */
+				fil_decompress_page(
+					NULL, read_buf, UNIV_PAGE_SIZE,
+					NULL, true);
+			}
+
+			if (fil_space_verify_crypt_checksum(
+				   read_buf, zip_size)
+			   || !buf_page_is_corrupted(
+				   true, read_buf, zip_size)) {
+				/* The page is good; there is no need
+				to consult the doublewrite buffer. */
+				continue;
+			}
+
+			/* We intentionally skip this message for
+			is_all_zero pages. */
+			ib_logf(IB_LOG_LEVEL_INFO,
+				"Trying to recover page " ULINTPF ":" ULINTPF
+				" from the doublewrite buffer.",
+				space_id, page_no);
+		}
+
+		/* Next, validate the doublewrite page. */
+		if (fil_page_is_compressed_encrypted(page) ||
+		    fil_page_is_compressed(page)) {
+			/* Decompress the page before
+			validating the checksum. */
+			fil_decompress_page(
+				NULL, page, UNIV_PAGE_SIZE, NULL, true);
+		}
+
+		if (!fil_space_verify_crypt_checksum(page, zip_size)
+		    && buf_page_is_corrupted(true, page, zip_size)) {
+			if (!is_all_zero) {
+				ib_logf(IB_LOG_LEVEL_WARN,
+					"A doublewrite copy of page "
+					ULINTPF ":" ULINTPF " is corrupted.",
+					space_id, page_no);
+			}
+			/* Theoretically we could have another good
+			copy for this page in the doublewrite
+			buffer. If not, we will report a fatal error
+			for a corrupted page somewhere else if that
+			page was truly needed. */
+			continue;
+		}
+
+		/* Write the good page from the doublewrite buffer to
+		the intended position. */
+
+		fil_io(OS_FILE_WRITE, true, space_id, zip_size, page_no, 0,
+		       zip_size ? zip_size : UNIV_PAGE_SIZE,
+		       page, NULL, 0);
+
+		ib_logf(IB_LOG_LEVEL_INFO,
+			"Recovered page " ULINTPF ":" ULINTPF " from"
+			" the doublewrite buffer.",
+			space_id, page_no);
 	}
 
 	ut_free(unaligned_read_buf);