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Code Issues Releases Activity

Provide backward compatibility for decompression bug

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This commit is contained in:
Konstantin Knizhnik 2018-11-08 12:27:42 +03:00
parent 45940cb587
commit 05e3211e27
2 changed files with 61 additions and 4 deletions
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63
src/data.c
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@ -99,6 +99,55 @@ do_decompress(void* dst, size_t dst_size, void const* src, size_t src_size,
return -1;
}
#define ZLIB_MAGIC 0x78
/*
* Before version 2.0.23 there was a bug in pro_backup that pages which compressed
* size is exactly the same as original size are not treated as compressed.
* This check tries to detect and decompress such pages.
* There is no 100% criteria to determine whether page is compressed or not.
* But at least we will do this check only for pages which will no pass validation step.
*/
static bool
page_may_be_compressed(Page page, CompressAlg alg)
{
PageHeader phdr;
phdr = (PageHeader) page;
/* First check if page header is valid (it seems to be fast enough check) */
if (!(PageGetPageSize(phdr) == BLCKSZ &&
PageGetPageLayoutVersion(phdr) == PG_PAGE_LAYOUT_VERSION &&
(phdr->pd_flags & ~PD_VALID_FLAG_BITS) == 0 &&
phdr->pd_lower >= SizeOfPageHeaderData &&
phdr->pd_lower <= phdr->pd_upper &&
phdr->pd_upper <= phdr->pd_special &&
phdr->pd_special <= BLCKSZ &&
phdr->pd_special == MAXALIGN(phdr->pd_special)))
{
/* ... end only if it is invalid, then do more checks */
int major, middle, minor;
if ( parse_program_version(current.program_version) >= 20023)
{
/* Versions 2.0.23 and higher don't have such bug */
return false;
}
#ifdef HAVE_LIBZ
/* For zlib we can check page magic:
* https://stackoverflow.com/questions/9050260/what-does-a-zlib-header-look-like
*/
if (alg == ZLIB_COMPRESS && *(char*)page != ZLIB_MAGIC)
{
return false;
}
#endif
/* otherwize let's try to decompress the page */
return true;
}
return false;
}
/*
* When copying datafiles to backup we validate and compress them block
* by block. Thus special header is required for each data block.
@ -717,7 +766,8 @@ restore_data_file(const char *to_path, pgFile *file, bool allow_truncate,
elog(ERROR, "cannot read block %u of \"%s\" read %lu of %d",
blknum, file->path, read_len, header.compressed_size);
if (header.compressed_size != BLCKSZ)
if (header.compressed_size != BLCKSZ
|| page_may_be_compressed(compressed_page.data, file->compress_alg))
{
int32 uncompressed_size = 0;
@ -1595,7 +1645,8 @@ check_file_pages(pgFile *file, XLogRecPtr stop_lsn, uint32 checksum_version)
elog(ERROR, "cannot read block %u of \"%s\" read %lu of %d",
blknum, file->path, read_len, header.compressed_size);
if (header.compressed_size != BLCKSZ)
if (header.compressed_size != BLCKSZ
|| page_may_be_compressed(compressed_page.data, file->compress_alg))
{
int32 uncompressed_size = 0;
@ -1605,9 +1656,15 @@ check_file_pages(pgFile *file, XLogRecPtr stop_lsn, uint32 checksum_version)
file->compress_alg);
if (uncompressed_size != BLCKSZ)
{
if (header.compressed_size == BLCKSZ)
{
is_valid = false;
continue;
}
elog(ERROR, "page of file \"%s\" uncompressed to %d bytes. != BLCKSZ",
file->path, uncompressed_size);
}
if (validate_one_page(page.data, file, blknum,
stop_lsn, checksum_version) == PAGE_IS_FOUND_AND_NOT_VALID)
is_valid = false;

2
src/pg_probackup.c
View File

@ -17,7 +17,7 @@
#include "utils/thread.h"
const char *PROGRAM_VERSION = "2.0.22";
const char *PROGRAM_VERSION = "2.0.23";
const char *PROGRAM_URL = "https://github.com/postgrespro/pg_probackup";
const char *PROGRAM_EMAIL = "https://github.com/postgrespro/pg_probackup/issues";