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MDEV-21918 improve page_zip_verify_checksum()

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actually, page_zip_verify_checksum() generally allows all-zeroes
checksums because our CRC32 checksum is something like
crc_1 ^ crc_2 ^ crc_3

Also, all zeroes page is considered correct.

As a side effect fix nasty reinterpret_cast<> UB

Also, since c0f47a4a58 innodb_checksum_algorithm=full_crc32
exists which computes CRC32 in one go (without bitwise arithmetic)
This commit is contained in:
Eugene Kosov 2020-03-11 16:40:34 +03:00
parent df88e7cefa
commit 7f36300df5
2 changed files with 32 additions and 46 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

39
storage/innobase/page/page0zip.cc
View file

@ -4918,35 +4918,28 @@ page_zip_verify_checksum(
ib_uint32_t crc32 = 0 /* silence bogus warning */; ib_uint32_t crc32 = 0 /* silence bogus warning */;
ib_uint32_t innodb = 0 /* silence bogus warning */; ib_uint32_t innodb = 0 /* silence bogus warning */;
stored = static_cast<ib_uint32_t>(mach_read_from_4(
static_cast<const unsigned char*>(data) + FIL_PAGE_SPACE_OR_CHKSUM));
#if FIL_PAGE_LSN % 8
#error "FIL_PAGE_LSN must be 64 bit aligned"
#endif
/* Check if page is empty */
if (stored == 0
&& *reinterpret_cast<const ib_uint64_t*>(static_cast<const char*>(
data)
+ FIL_PAGE_LSN) == 0) {
/* make sure that the page is really empty */
for (ulint i = 0; i < size; i++) {
if (*((const char*) data + i) != 0) {
return(FALSE);
}
}
/* Empty page */
return(TRUE);
}
const srv_checksum_algorithm_t curr_algo = const srv_checksum_algorithm_t curr_algo =
static_cast<srv_checksum_algorithm_t>(srv_checksum_algorithm); static_cast<srv_checksum_algorithm_t>(srv_checksum_algorithm);
if (curr_algo == SRV_CHECKSUM_ALGORITHM_NONE) { if (curr_algo == SRV_CHECKSUM_ALGORITHM_NONE) {
return(TRUE); return true;
} }
bool all_zeroes = true;
for (size_t i = 0; i < size; i++) {
if (static_cast<const byte*>(data)[i] != 0) {
all_zeroes = false;
break;
}
}
if (all_zeroes) {
return true;
}
stored = static_cast<ib_uint32_t>(mach_read_from_4(
static_cast<const unsigned char*>(data) + FIL_PAGE_SPACE_OR_CHKSUM));
calc = static_cast<ib_uint32_t>(page_zip_calc_checksum( calc = static_cast<ib_uint32_t>(page_zip_calc_checksum(
data, size, curr_algo)); data, size, curr_algo));

39
storage/xtradb/page/page0zip.cc
View file

@ -4927,35 +4927,28 @@ page_zip_verify_checksum(
ib_uint32_t crc32 = 0 /* silence bogus warning */; ib_uint32_t crc32 = 0 /* silence bogus warning */;
ib_uint32_t innodb = 0 /* silence bogus warning */; ib_uint32_t innodb = 0 /* silence bogus warning */;
stored = static_cast<ib_uint32_t>(mach_read_from_4(
static_cast<const unsigned char*>(data) + FIL_PAGE_SPACE_OR_CHKSUM));
#if FIL_PAGE_LSN % 8
#error "FIL_PAGE_LSN must be 64 bit aligned"
#endif
/* Check if page is empty */
if (stored == 0
&& *reinterpret_cast<const ib_uint64_t*>(static_cast<const char*>(
data)
+ FIL_PAGE_LSN) == 0) {
/* make sure that the page is really empty */
for (ulint i = 0; i < size; i++) {
if (*((const char*) data + i) != 0) {
return(FALSE);
}
}
/* Empty page */
return(TRUE);
}
const srv_checksum_algorithm_t curr_algo = const srv_checksum_algorithm_t curr_algo =
static_cast<srv_checksum_algorithm_t>(srv_checksum_algorithm); static_cast<srv_checksum_algorithm_t>(srv_checksum_algorithm);
if (curr_algo == SRV_CHECKSUM_ALGORITHM_NONE) { if (curr_algo == SRV_CHECKSUM_ALGORITHM_NONE) {
return(TRUE); return true;
} }
bool all_zeroes = true;
for (size_t i = 0; i < size; i++) {
if (static_cast<const byte*>(data)[i] != 0) {
all_zeroes = false;
break;
}
}
if (all_zeroes) {
return true;
}
stored = static_cast<ib_uint32_t>(mach_read_from_4(
static_cast<const unsigned char*>(data) + FIL_PAGE_SPACE_OR_CHKSUM));
calc = static_cast<ib_uint32_t>(page_zip_calc_checksum( calc = static_cast<ib_uint32_t>(page_zip_calc_checksum(
data, size, curr_algo)); data, size, curr_algo));