145 lines
6.6 KiB
C
145 lines
6.6 KiB
C
/****************************************************************
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* *
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* Copyright 2001, 2013 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include <signal.h> /* for VSIG_ATOMIC_T type */
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#include "gdsroot.h"
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#include "gtm_facility.h"
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#include "fileinfo.h"
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#include "gdsbt.h"
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#include "gdsfhead.h"
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#include "filestruct.h"
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#include "mutex.h"
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#include "deferred_signal_handler.h"
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#include "caller_id.h"
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#include "is_proc_alive.h"
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#include "repl_msg.h"
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#include "gtmsource.h"
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#include "repl_instance.h"
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#include "jnl.h"
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#include "gtmimagename.h" /* for IS_GTCM_GNP_SERVER_IMAGE */
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#include "anticipatory_freeze.h"
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#include "util.h" /* for OUT_BUFF_SIZE */
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GBLREF volatile int4 crit_count;
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GBLREF uint4 process_id;
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GBLREF node_local_ptr_t locknl;
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GBLREF jnlpool_addrs jnlpool;
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GBLREF jnl_gbls_t jgbl;
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GBLREF boolean_t is_src_server;
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GBLREF boolean_t jnlpool_init_needed;
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error_def(ERR_DBCCERR);
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error_def(ERR_CRITRESET);
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error_def(ERR_REPLREQROLLBACK);
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error_def(ERR_TEXT);
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/* Note about usage of this function : Create dummy gd_region, gd_segment, file_control,
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* unix_db_info, sgmnt_addrs, and allocate mutex_struct (and NUM_CRIT_ENTRY * mutex_que_entry),
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* mutex_spin_parms_struct, and node_local in shared memory. Initialize the fields as in
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* jnlpool_init(). Pass the address of the dummy region as argument to this function.
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*/
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boolean_t grab_lock(gd_region *reg, boolean_t is_blocking_wait, uint4 onln_rlbk_action)
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{
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unix_db_info *udi;
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sgmnt_addrs *csa;
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enum cdb_sc status;
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mutex_spin_parms_ptr_t mutex_spin_parms;
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char scndry_msg[OUT_BUFF_SIZE];
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# ifdef DEBUG
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DCL_THREADGBL_ACCESS;
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SETUP_THREADGBL_ACCESS;
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# endif
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udi = FILE_INFO(reg);
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csa = &udi->s_addrs;
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assert(!csa->hold_onto_crit);
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assert(!csa->now_crit);
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if (!csa->now_crit)
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{
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assert(0 == crit_count);
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crit_count++; /* prevent interrupts */
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DEBUG_ONLY(locknl = csa->nl); /* for DEBUG_ONLY LOCK_HIST macro */
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mutex_spin_parms = (mutex_spin_parms_ptr_t)((sm_uc_ptr_t)csa->critical + JNLPOOL_CRIT_SPACE);
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/* This assumes that mutex_spin_parms_t is located immediately after the crit structures */
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/* As of 10/07/98, crashcnt field in mutex_struct is not changed by any function for the dummy region */
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if (is_blocking_wait)
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status = mutex_lockw(reg, mutex_spin_parms, 0);
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else
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status = mutex_lockwim(reg, mutex_spin_parms, 0);
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DEBUG_ONLY(locknl = NULL); /* restore "locknl" to default value */
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if (status != cdb_sc_normal)
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{
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crit_count = 0;
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switch(status)
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{
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case cdb_sc_critreset: /* As of 10/07/98, this return value is not possible */
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rts_error(VARLSTCNT(4) ERR_CRITRESET, 2, REG_LEN_STR(reg));
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case cdb_sc_dbccerr:
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rts_error(VARLSTCNT(4) ERR_DBCCERR, 2, REG_LEN_STR(reg));
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case cdb_sc_nolock:
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return FALSE;
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default:
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GTMASSERT;
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}
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return FALSE;
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}
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/* There is only one case we know of when csa->nl->in_crit can be non-zero and that is when a process holding
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* crit gets kill -9ed and another process ends up invoking "secshr_db_clnup" which in turn clears the
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* crit semaphore (making it available for waiters) but does not also clear csa->nl->in_crit since it does not
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* hold crit at that point. But in that case, the pid reported in csa->nl->in_crit should be dead. Check that.
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*/
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assert((0 == csa->nl->in_crit) || (FALSE == is_proc_alive(csa->nl->in_crit, 0)));
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csa->nl->in_crit = process_id;
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CRIT_TRACE(crit_ops_gw); /* see gdsbt.h for comment on placement */
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crit_count = 0;
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if (jnlpool.repl_inst_filehdr->file_corrupt && !jgbl.onlnrlbk)
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{ /* Journal pool indicates an abnormally terminated online rollback. Cannot continue until the rollback
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* command is re-run to bring the journal pool/file and instance file to a consistent state.
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*/
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SNPRINTF(scndry_msg, OUT_BUFF_SIZE, "Instance file header has file_corrupt field set to TRUE");
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/* No need to do rel_lock before rts_error (mupip_exit_handler will do it for us) */
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rts_error(VARLSTCNT(8) ERR_REPLREQROLLBACK, 2, LEN_AND_STR(udi->fn), ERR_TEXT, 2, LEN_AND_STR(scndry_msg));
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}
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/* If ASSERT_NO_ONLINE_ROLLBACK, then no concurrent online rollbacks can happen at this point. So, the jnlpool
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* should be in in sync. There are two exceptions. If this is GT.CM GNP Server and the last client disconnected, the
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* server invokes gtcmd_rundown which in-turn invokes gds_rundown thereby running down all active databases at this
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* point but leaves the journal pool up and running. Now, if an online rollback is attempted, it increments the
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* onln_rlbk_cycle in the journal pool, but csa->onln_rlbk_cycle is not synced yet. So, the grab_crit done in t_end
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* will NOT detect a concurrent online rollback and it doesn't need to because the rollback happened AFTER the
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* rundown. Assert that this is the only case we know of for the cycles to be out-of-sync. In PRO
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* jnlpool_ctl->onln_rlbk_cycle is used only by the replication servers (which GT.CM is not) and so even if it
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* continues with an out-of-sync csa->onln_rlbk_cycle, t_end logic does the right thing. The other exception is if
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* GT.M initialized journal pool while opening database (belonging to a different instance) in gvcst_init (for
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* anticipatory freeze) followed by an online rollback which increments the jnlpool_ctl->onln_rlbk_cycle but leaves
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* the repl_csa->onln_rlbk_cycle out-of-sync. At this point, if a replicated database is open for the first time,
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* we'll reach t_end to commit the update but will end up failing the below assert due to the out-of-sync
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* onln_rlbk_cycle. So, assert accordingly. Note : even though the cycles are out-of-sync they are not an issue for
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* GT.M because it always relies on the onln_rlbk_cycle from csa->nl and not from repl_csa. But, we don't remove the
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* assert as it is valuable for replication servers (Source, Receiver and Update Process).
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*/
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assert((ASSERT_NO_ONLINE_ROLLBACK != onln_rlbk_action)
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|| (csa->onln_rlbk_cycle == jnlpool.jnlpool_ctl->onln_rlbk_cycle) || IS_GTCM_GNP_SERVER_IMAGE
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|| (jnlpool_init_needed && ANTICIPATORY_FREEZE_AVAILABLE));
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if ((HANDLE_CONCUR_ONLINE_ROLLBACK == onln_rlbk_action)
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&& (csa->onln_rlbk_cycle != jnlpool.jnlpool_ctl->onln_rlbk_cycle))
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{
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assert(is_src_server);
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SYNC_ONLN_RLBK_CYCLES;
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gtmsource_onln_rlbk_clnup(); /* side-effect : sets gtmsource_state */
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rel_lock(reg); /* caller knows to disconnect and re-establish the connection */
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}
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}
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return TRUE;
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}
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