fis-gtm/sr_port/mu_int_write.c

76 lines
3.0 KiB
C

/****************************************************************
* *
* Copyright 2001, 2009 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gdsroot.h"
#include "gtm_facility.h"
#include "fileinfo.h"
#include "gdsbt.h"
#include "gdsfhead.h"
#include "dbfilop.h"
#include "gdsblk.h"
#include "gds_blk_downgrade.h"
#include "mupint.h"
GBLREF sm_uc_ptr_t reformat_buffer;
GBLREF int reformat_buffer_len;
GBLREF volatile int reformat_buffer_in_use; /* used only in DEBUG mode */
GBLREF unsigned char *mu_int_locals;
GBLREF int4 mu_int_ovrhd;
GBLREF sgmnt_data mu_int_data;
GBLREF gd_region *gv_cur_region;
GBLREF volatile int4 fast_lock_count;
void mu_int_write(block_id blk, uchar_ptr_t ptr)
{
file_control *fc;
assert(0 == fast_lock_count);
++fast_lock_count; /* No interrupts across this use of reformat_buffer */
/* reformat_buffer_in_use should always be incremented only AFTER incrementing fast_lock_count
* as it is the latter that prevents interrupts from using the reformat buffer. Similarly
* the decrement of fast_lock_count should be done AFTER decrementing reformat_buffer_in_use.
*/
assert(0 == reformat_buffer_in_use);
DEBUG_ONLY(reformat_buffer_in_use++;)
if (IS_GDS_BLK_DOWNGRADE_NEEDED(mu_int_data.desired_db_format))
{
if (reformat_buffer_len < mu_int_data.blk_size)
{
if (reformat_buffer)
free(reformat_buffer);
reformat_buffer = malloc(mu_int_data.blk_size);
reformat_buffer_len = mu_int_data.blk_size;
}
gds_blk_downgrade((v15_blk_hdr_ptr_t)reformat_buffer, (blk_hdr_ptr_t)ptr);
ptr = reformat_buffer;
}
fc = gv_cur_region->dyn.addr->file_cntl;
fc->op = FC_WRITE;
fc->op_buff = ptr;
/* Previously, fc->op_len was set to mu_int_data.blk_size. Although only the transaction number in the block header is
* going to be reset, we were writing the entire buffer (mu_int_data.blk_size). This demanded a encryption
* of the buffer before being written to the disk. To avoid an encryption, we are only going to write the block header
* in the desired offset(op_pos). Note that since mu_int_write is called just after an mu_int_read, the block previously
* read will be in the OS cache and hence won't cause performance issues due to unaligned writes. When the database is
* not fully upgraded from V4 to V5, we will be writing the entrie block size. This is due to the block upgrades between
* V4 and V5 that can happen in the unencrypted versions of the database. */
fc->op_len = UNIX_ONLY(mu_int_data.fully_upgraded ? SIZEOF(blk_hdr) : ) mu_int_data.blk_size;
fc->op_pos = mu_int_ovrhd + (mu_int_data.blk_size / DISK_BLOCK_SIZE * blk);
dbfilop(fc);
DEBUG_ONLY(reformat_buffer_in_use--;)
assert(0 == reformat_buffer_in_use);
--fast_lock_count;
assert(0 == fast_lock_count);
return;
}