fis-gtm/sr_unix/tp_grab_crit.c

93 lines
3.1 KiB
C

/****************************************************************
* *
* Copyright 2001, 2008 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 <signal.h> /* for VSIG_ATOMIC_T type */
#include "gdsroot.h"
#include "gtm_facility.h"
#include "fileinfo.h"
#include "gdsbt.h"
#include "gdsfhead.h"
#include "gdsbgtr.h"
#include "filestruct.h"
#include "send_msg.h"
#include "mutex.h"
#include "tp_grab_crit.h"
#include "deferred_signal_handler.h"
#include "wcs_recover.h"
#include "caller_id.h"
#include "is_proc_alive.h"
GBLREF short crash_count;
GBLREF volatile int4 crit_count;
GBLREF uint4 process_id;
GBLREF node_local_ptr_t locknl;
bool tp_grab_crit(gd_region *reg)
{
unix_db_info *udi;
sgmnt_addrs *csa;
enum cdb_sc status;
mutex_spin_parms_ptr_t mutex_spin_parms;
error_def(ERR_CRITRESET);
error_def(ERR_DBCCERR);
udi = FILE_INFO(reg);
csa = &udi->s_addrs;
if (!csa->now_crit)
{
assert(0 == crit_count);
crit_count++; /* prevent interrupts */
DEBUG_ONLY(locknl = csa->nl;) /* for DEBUG_ONLY LOCK_HIST macro */
mutex_spin_parms = (mutex_spin_parms_ptr_t)&csa->hdr->mutex_spin_parms;
status = mutex_lockwim(reg, mutex_spin_parms, crash_count);
DEBUG_ONLY(locknl = NULL;) /* restore "locknl" to default value */
if (status != cdb_sc_normal)
{
crit_count = 0;
switch (status)
{
case cdb_sc_nolock:
return(FALSE);
case cdb_sc_critreset:
rts_error(VARLSTCNT(4) ERR_CRITRESET, 2, REG_LEN_STR(reg));
case cdb_sc_dbccerr:
rts_error(VARLSTCNT(4) ERR_DBCCERR, 2, REG_LEN_STR(reg));
default:
GTMASSERT;
}
return(FALSE);
}
/* There is only one case we know of when csa->nl->in_crit can be non-zero and that is when a process holding
* crit gets kill -9ed and another process ends up invoking "secshr_db_clnup" which in turn clears the
* crit semaphore (making it available for waiters) but does not also clear csa->nl->in_crit since it does not
* hold crit at that point. But in that case, the pid reported in csa->nl->in_crit should be dead. Check that.
*/
assert((0 == csa->nl->in_crit) || (FALSE == is_proc_alive(csa->nl->in_crit, 0)));
csa->nl->in_crit = process_id;
CRIT_TRACE(crit_ops_gw); /* see gdsbt.h for comment on placement */
crit_count = 0;
}
/* Ideally we do not want to do wcs_recover if we are in interrupt code (as opposed to mainline code).
* This is easily accomplished in VMS with a library function lib$ast_in_prog but in Unix there is no way
* to tell mainline code from interrupt code without the caller providing that information. Hence we
* currently do the cache recovery even in case of interrupt code even though it is a heavyweight operation.
* If it is found to cause issues, this logic has to be re-examined.
*/
if (csa->hdr->wc_blocked)
wcs_recover(reg);
return(TRUE);
}