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.

14 files changed, 191 insertions, 295 deletions

diff --git a/mysql-test/suite/innodb/r/group_commit_crash.result b/mysql-test/suite/innodb/r/group_commit_crash.result
index 5d5dffab33e..005049df281 100644
--- a/mysql-test/suite/innodb/r/group_commit_crash.result
+++ b/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),
diff --git a/mysql-test/suite/innodb/r/group_commit_crash_no_optimize_thread.result b/mysql-test/suite/innodb/r/group_commit_crash_no_optimize_thread.result
index 542ce9d496e..846500ad2b1 100644
--- a/mysql-test/suite/innodb/r/group_commit_crash_no_optimize_thread.result
+++ b/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),
diff --git a/mysql-test/suite/innodb/r/innodb-alter-tempfile.result b/mysql-test/suite/innodb/r/innodb-alter-tempfile.result
index 3cc973ca3a3..ce13ad0978b 100644
--- a/mysql-test/suite/innodb/r/innodb-alter-tempfile.result
+++ b/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';
diff --git a/mysql-test/suite/innodb/r/innodb_bug14147491.result b/mysql-test/suite/innodb/r/innodb_bug14147491.result
index bd3c388fae1..5ff6f652f9e 100644
--- a/mysql-test/suite/innodb/r/innodb_bug14147491.result
+++ b/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.");
diff --git a/mysql-test/suite/innodb/r/xa_recovery.result b/mysql-test/suite/innodb/r/xa_recovery.result
index e65f702c488..f429808b8dd 100644
--- a/mysql-test/suite/innodb/r/xa_recovery.result
+++ b/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;
diff --git a/mysql-test/suite/innodb/t/group_commit_crash.test b/mysql-test/suite/innodb/t/group_commit_crash.test
index cad349819bd..7ad0d9d1e74 100644
--- a/mysql-test/suite/innodb/t/group_commit_crash.test
+++ b/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),
diff --git a/mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test b/mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test
index 8d1f460b64b..9dc2557e687 100644
--- a/mysql-test/suite/innodb/t/group_commit_crash_no_optimize_thread.test
+++ b/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),
diff --git a/mysql-test/suite/innodb/t/innodb-alter-tempfile.test b/mysql-test/suite/innodb/t/innodb-alter-tempfile.test
index e1e736fc678..ec1ea35f1cf 100644
--- a/mysql-test/suite/innodb/t/innodb-alter-tempfile.test
+++ b/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`
diff --git a/mysql-test/suite/innodb/t/innodb_bug14147491.test b/mysql-test/suite/innodb/t/innodb_bug14147491.test
index 16e88826c85..d48fa074147 100644
--- a/mysql-test/suite/innodb/t/innodb_bug14147491.test
+++ b/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.");
diff --git a/mysql-test/suite/innodb/t/xa_recovery.test b/mysql-test/suite/innodb/t/xa_recovery.test
index 32373d63d14..9f25e4d1f30 100644
--- a/mysql-test/suite/innodb/t/xa_recovery.test
+++ b/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.
--- exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
--- 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
+--source include/kill_mysqld.inc
+--source include/start_mysqld.inc
 
 disconnect con1;
 connect (con1,localhost,root);
diff --git a/mysql-test/suite/rpl/r/rpl_gtid_crash.result b/mysql-test/suite/rpl/r/rpl_gtid_crash.result
index 0c2249f2dce..5f67901b7f5 100644
--- a/mysql-test/suite/rpl/r/rpl_gtid_crash.result
+++ b/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;
diff --git a/mysql-test/suite/rpl/t/rpl_gtid_crash.test b/mysql-test/suite/rpl/t/rpl_gtid_crash.test
index df3ba9a3420..b81cbd38cd3 100644
--- a/mysql-test/suite/rpl/t/rpl_gtid_crash.test
+++ b/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;
diff --git a/storage/innobase/buf/buf0dblwr.cc b/storage/innobase/buf/buf0dblwr.cc
index 1cf856a731f..0b42e38a655 100644
--- a/storage/innobase/buf/buf0dblwr.cc
+++ b/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)) {
+		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);
+				"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 {
-			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_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)) {
-				/* 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(
+				   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;
+			}
 
-				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;
-				}
+			/* 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);
+		}
 
-				/* 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);
-				}
+		/* 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);
diff --git a/storage/xtradb/buf/buf0dblwr.cc b/storage/xtradb/buf/buf0dblwr.cc
index 7f6b6caee9d..9c7eea6410a 100644
--- a/storage/xtradb/buf/buf0dblwr.cc
+++ b/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)) {
+		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);
+				"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 {
-			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_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)) {
-				/* 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(
+				   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;
+			}
 
-				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;
-				}
+			/* 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);
+		}
 
-				/* 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);
-				}
+		/* 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);