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fis-gtm/sr_unix/ss_initiate.c

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/****************************************************************
* *
* Copyright 2009, 2013 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 "gtm_fcntl.h"
#include "gtm_stat.h"
#include "gtm_unistd.h"
#include "gtm_permissions.h"
#include "gtm_string.h"
#include "gtm_stdio.h"
#include "gtm_stdlib.h"
#include "gtm_tempnam.h"
#include "gtm_time.h"
#include "gdsroot.h"
#include "gdskill.h"
#include "gtm_facility.h"
#include "fileinfo.h"
#include "gdsbt.h"
#include "gdsblk.h"
#include "gdsfhead.h"
#include "filestruct.h"
#include "iosp.h"
#include "error.h"
#include "cli.h"
#include "eintr_wrappers.h"
#include "gtmio.h"
#include "repl_sp.h"
#include "gtm_file_stat.h"
#include "util.h"
#include "gtm_caseconv.h"
#include "gt_timer.h"
#include "is_proc_alive.h"
#include "wcs_flu.h"
#include "jnl.h"
#include "wcs_sleep.h"
#include "interlock.h"
#include "add_inter.h"
#include "sleep_cnt.h"
#include "trans_log_name.h"
#include "mupint.h"
#include "memcoherency.h"
#include "gtm_logicals.h"
#ifdef __MVS__
#include "gtm_zos_io.h"
#endif
#include "shmpool.h"
#include "db_snapshot.h"
#include "gtm_c_stack_trace.h"
#include "sys/shm.h"
#include "do_shmat.h"
#include "have_crit.h"
#include "ss_lock_facility.h"
#include "gtmimagename.h"
GBLREF uint4 process_id;
GBLREF uint4 mu_int_errknt;
GBLREF boolean_t ointeg_this_reg;
GBLREF boolean_t online_specified;
GBLREF gd_region *gv_cur_region;
GBLREF void (*call_on_signal)();
GBLREF int process_exiting;
GBLREF boolean_t muint_fast;
error_def(ERR_BUFFLUFAILED);
error_def(ERR_DBROLLEDBACK);
error_def(ERR_FILEPARSE);
error_def(ERR_MAXSSREACHED);
error_def(ERR_PERMGENFAIL);
error_def(ERR_SSFILOPERR);
error_def(ERR_SSTMPCREATE);
error_def(ERR_SSTMPDIRSTAT);
error_def(ERR_SSV4NOALLOW);
error_def(ERR_SYSCALL);
ZOS_ONLY(error_def(ERR_BADTAG);)
ZOS_ONLY(error_def(ERR_TEXT);)
#define SNAPSHOT_TMP_PREFIX "gtm_snapshot_"
#define ISSUE_WRITE_ERROR_AND_EXIT(reg, RC, csa, tempfilename) \
{ \
gtm_putmsg(VARLSTCNT(7) ERR_SSFILOPERR, 4, LEN_AND_LIT("write"), LEN_AND_STR(tempfilename), RC); \
if (csa->now_crit) \
rel_crit(csa->region); \
UNFREEZE_REGION_IF_NEEDED(csa->hdr, reg); \
return FALSE; \
}
#define TOT_BYTES_REQUIRED(BLKS) DIVIDE_ROUND_UP(BLKS, 8) /* One byte can represent 8 blocks' before image state */
#define EOF_MARKER_SIZE DISK_BLOCK_SIZE
#define MAX_TRY_FOR_TOT_BLKS 3 /* This value is the # of tries we do outside of crit in the hope that no
* concurrent db extensions occur. This is chosen to be the same as
* CDB_STAGNATE but is kept as a different name because there is no reason
* for it to be the same.
*/
#define FILL_SS_FILHDR_INFO(ss_shm_ptr, ss_filhdr_ptr) \
{ \
MEMCPY_LIT(ss_filhdr_ptr->label, SNAPSHOT_HDR_LABEL); \
ss_filhdr_ptr->ss_info.ss_pid = ss_shm_ptr->ss_info.ss_pid; \
ss_filhdr_ptr->ss_info.snapshot_tn = ss_shm_ptr->ss_info.snapshot_tn; \
ss_filhdr_ptr->ss_info.db_blk_size = ss_shm_ptr->ss_info.db_blk_size; \
ss_filhdr_ptr->ss_info.free_blks = ss_shm_ptr->ss_info.free_blks; \
ss_filhdr_ptr->ss_info.total_blks = ss_shm_ptr->ss_info.total_blks; \
STRCPY(ss_filhdr_ptr->ss_info.shadow_file, ss_shm_ptr->ss_info.shadow_file); \
ss_filhdr_ptr->shadow_file_len = STRLEN((ss_shm_ptr->ss_info.shadow_file)); \
ss_filhdr_ptr->ss_info.shadow_vbn = ss_shm_ptr->ss_info.shadow_vbn; \
ss_filhdr_ptr->ss_info.ss_shmsize = ss_shm_ptr->ss_info.ss_shmsize; \
}
#define GET_CRIT_AND_DECR_INHIBIT_KILLS(REG, CNL) \
{ \
grab_crit(REG); \
DECR_INHIBIT_KILLS(CNL); \
rel_crit(REG); \
}
#define SS_INIT_SHM(SS_SHMSIZE, SS_SHMADDR, SS_SHMID, RESIZE_NEEDED, RC) \
{ \
RC = 0; \
\
if (RESIZE_NEEDED) \
{ \
assert(INVALID_SHMID != SS_SHMID); \
assert(NULL != SS_SHMADDR); \
assert(0 == ((long)SS_SHMADDR % OS_PAGE_SIZE)); \
if (0 != SHMDT(SS_SHMADDR)) \
{ \
RC = errno; \
assert(FALSE); \
gtm_putmsg(VARLSTCNT(8) ERR_SYSCALL, 5, LEN_AND_LIT("Error with shmdt"), \
CALLFROM, RC); \
} \
if (0 != shmctl(SS_SHMID, IPC_RMID, 0)) \
{ \
RC = errno; \
assert(FALSE); \
gtm_putmsg(VARLSTCNT(8) ERR_SYSCALL, 5, LEN_AND_LIT("Error with shmctl"), \
CALLFROM, RC); \
} \
} \
SS_SHMID = shmget(IPC_PRIVATE, SS_SHMSIZE, RWDALL | IPC_CREAT); \
if (-1 == SS_SHMID) \
{ \
RC = errno; \
assert(FALSE); \
gtm_putmsg(VARLSTCNT(8) ERR_SYSCALL, 5, LEN_AND_LIT("Error with shmget"), CALLFROM, \
RC); \
} \
if (-1 == (sm_long_t)(SS_SHMADDR = do_shmat(SS_SHMID, 0, 0))) \
{ \
RC = errno; \
assert(FALSE); \
gtm_putmsg(VARLSTCNT(8) ERR_SYSCALL, 5, LEN_AND_LIT("Error with shmat"), CALLFROM, \
RC); \
} \
}
/* In case of an error, un-freeze the region before returning if we had done the region_freeze
* in mu_int_reg for a read_only process
*/
#define UNFREEZE_REGION_IF_NEEDED(CSD, REG) \
{ \
if (process_id == CSD->freeze) \
{ \
assert(reg->read_only); \
region_freeze(reg, FALSE, FALSE, FALSE); \
} \
}
/* The below function is modelled around mupip_backup_call_on_signal. This is invoked for doing snapshot clean up if ss_initiate
* gets interrupted by a MUPIP STOP or other interruptible signals. In such cases, information would not have been transferred to
* database shared memory and hence gds_rundown cannot do the cleanup.
*/
void ss_initiate_call_on_signal(void)
{
sgmnt_addrs *csa;
csa = &FILE_INFO(gv_cur_region)->s_addrs;
call_on_signal = NULL; /* Do not recurse via call_on_signal if there is an error */
assert(process_exiting); /* Set by generic_signal_handler() */
assert(NULL != csa->ss_ctx);
ss_release(&csa->ss_ctx);
return;
}
boolean_t ss_initiate(gd_region *reg, /* Region in which snapshot has to be started */
util_snapshot_ptr_t util_ss_ptr, /* Utility specific snapshot structure */
snapshot_context_ptr_t *ss_ctx, /* Snapshot context */
boolean_t preserve_snapshot, /* Should the snapshots be preserved ? */
char *calling_utility) /* Who called ss_initiate */
{
sgmnt_addrs *csa;
sgmnt_data_ptr_t csd;
node_local_ptr_t cnl;
shm_snapshot_ptr_t ss_shm_ptr;
snapshot_context_ptr_t lcl_ss_ctx, ss_orphan_ctx;
snapshot_filhdr_ptr_t ss_filhdr_ptr;
int shdw_fd, tmpfd, fclose_res, fstat_res, status, perm, group_id, pwrite_res, dsk_addr = 0;
int retries, idx, this_snapshot_idx, save_errno, ss_shmsize, ss_shm_vbn;
ZOS_ONLY(int realfiletag;)
long ss_shmid = INVALID_SHMID;
char tempnamprefix[MAX_FN_LEN + 1], tempdir_full_buffer[GTM_PATH_MAX], *tempfilename;
char tempdir_trans_buffer[GTM_PATH_MAX], eof_marker[EOF_MARKER_SIZE];
char *time_ptr, time_str[CTIME_BEFORE_NL + 2]; /* for GET_CUR_TIME macro */
struct stat stat_buf;
enum db_acc_method acc_meth;
void *ss_shmaddr;
gtm_uint64_t db_file_size, native_size;
uint4 tempnamprefix_len, crit_counter, tot_blks, prev_ss_shmsize, fstat_status;
pid_t *kip_pids_arr_ptr;
mstr tempdir_log, tempdir_full, tempdir_trans;
boolean_t debug_mupip = FALSE, wait_for_zero_kip, final_retry;
now_t now;
struct perm_diag_data pdd;
assert(IS_MUPIP_IMAGE);
assert(NULL != calling_utility);
csa = &FILE_INFO(reg)->s_addrs;
csd = csa->hdr;
cnl = csa->nl;
acc_meth = csd->acc_meth;
debug_mupip = (CLI_PRESENT == cli_present("DBG"));
/* Create a context containing default information pertinent to this initiate invocation */
lcl_ss_ctx = malloc(SIZEOF(snapshot_context_t)); /* should be free'd by ss_release */
DEFAULT_INIT_SS_CTX(lcl_ss_ctx);
call_on_signal = ss_initiate_call_on_signal;
/* Snapshot context created. Any error below before the next cur_state assignment and a later call to ss_release will
* have to free the malloc'ed snapshot context instance
*/
lcl_ss_ctx->cur_state = BEFORE_SHADOW_FIL_CREAT;
*ss_ctx = lcl_ss_ctx;
assert(!csa->now_crit); /* Right now mu_int_reg (which does not hold crit) is the only one that calls ss_initiate */
assert(!csa->hold_onto_crit); /* this ensures we can safely do unconditional grab_crit and rel_crit */
ss_get_lock(reg); /* Grab hold of the snapshot crit lock (low level latch) */
ss_shm_ptr = (shm_snapshot_ptr_t)SS_GETSTARTPTR(csa);
if (MAX_SNAPSHOTS == cnl->num_snapshots_in_effect)
{
/* SS_MULTI: If multiple snapshots are supported, then we should run through each of the "possibly" running
* snapshots
*/
assert(1 == MAX_SNAPSHOTS);
/* Check if the existing snapshot is still alive. If not, go ahead and cleanup that for us to continue */
if ((0 != ss_shm_ptr->ss_info.ss_pid) && !is_proc_alive(ss_shm_ptr->ss_info.ss_pid, 0))
ss_release(NULL);
else
{
gtm_putmsg(VARLSTCNT(5) ERR_MAXSSREACHED, 3, MAX_SNAPSHOTS, REG_LEN_STR(reg));
ss_release_lock(reg);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
}
ss_shm_ptr->ss_info.ss_pid = process_id;
cnl->num_snapshots_in_effect++;
assert(ss_lock_held_by_us(reg));
ss_release_lock(reg);
/* For a readonly database for the current process, we better have the region frozen */
assert(!reg->read_only || csd->freeze);
/* ============================ STEP 1 : Shadow file name construction ==============================
*
* --> Directory is taken from GTM_SNAPTMPDIR, if available, else GTM_BAK_TEMPDIR_LOG_NAME_UC, if available,
* else use current directory.
* --> use the template - gtm_snapshot_<region_name>_<pid_in_hex>_XXXXXX
* --> the last six characters will be replaced by MKSTEMP below
* Note: MUPIP RUNDOWN will rely on the above template to do the cleanup if there were a
* crash that led to the improper shutdown of the snapshot process. So, if the above template
* changes make sure it's taken care of in MUPIP RUNDOWN
* Note: most of the shadow file name construction and the creation of shadow file is been
* borrowed from mupip_backup.c. This code should be modularized and should be used in both mupip_backup
* as well as here.
*/
/* set up a prefix for the temporary file. */
tempnamprefix_len = 0;
memset(tempnamprefix, 0, MAX_FN_LEN);
memcpy(tempnamprefix, SNAPSHOT_TMP_PREFIX, STR_LIT_LEN(SNAPSHOT_TMP_PREFIX));
tempnamprefix_len += STR_LIT_LEN(SNAPSHOT_TMP_PREFIX);
memcpy(tempnamprefix + tempnamprefix_len, reg->rname, reg->rname_len);
tempnamprefix_len += reg->rname_len;
SNPRINTF(&tempnamprefix[tempnamprefix_len], MAX_FN_LEN, "_%x", process_id);
tempdir_log.addr = GTM_SNAPTMPDIR;
tempdir_log.len = STR_LIT_LEN(GTM_SNAPTMPDIR);
tempfilename = tempdir_full.addr = tempdir_full_buffer;
/* Check if the environment variable is defined or not.
* Side-effect: tempdir_trans.addr = tempdir_trans_buffer irrespective of whether TRANS_LOG_NAME
* succeeded or not.
*/
status = TRANS_LOG_NAME(&tempdir_log,
&tempdir_trans,
tempdir_trans_buffer,
SIZEOF(tempdir_trans_buffer),
do_sendmsg_on_log2long);
if (SS_NORMAL == status && (NULL != tempdir_trans.addr) && (0 != tempdir_trans.len))
*(tempdir_trans.addr + tempdir_trans.len) = 0;
else
{ /* Not found - try GTM_BAK_TEMPDIR_LOG_NAME_UC instead */
tempdir_log.addr = GTM_BAK_TEMPDIR_LOG_NAME_UC;
tempdir_log.len = STR_LIT_LEN(GTM_BAK_TEMPDIR_LOG_NAME_UC);
status = TRANS_LOG_NAME(&tempdir_log,
&tempdir_trans,
tempdir_trans_buffer,
SIZEOF(tempdir_trans_buffer),
do_sendmsg_on_log2long);
if (SS_NORMAL == status && (NULL != tempdir_trans.addr) && (0 != tempdir_trans.len))
*(tempdir_trans.addr + tempdir_trans.len) = 0;
else
{ /* Not found - use the current directory via a relative filespec */
tempdir_trans_buffer[0] = '.';
tempdir_trans_buffer[1] = '\0';
tempdir_trans.len = 1;
}
}
/* Verify if we can stat the temporary directory */
if (FILE_STAT_ERROR == (fstat_res = gtm_file_stat(&tempdir_trans, NULL, &tempdir_full, FALSE, &fstat_status)))
{
gtm_putmsg(VARLSTCNT(5) ERR_SSTMPDIRSTAT, 2, tempdir_trans.len, tempdir_trans.addr, fstat_status);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
SNPRINTF(tempfilename + tempdir_full.len, GTM_PATH_MAX, "/%s_XXXXXX", tempnamprefix);
/* ========================== STEP 2 : Create the shadow file ======================== */
/* get a unique temporary file name. The file gets created on success */
DEFER_INTERRUPTS(INTRPT_IN_SS_INITIATE); /* Defer MUPIP STOP till the file is created */
MKSTEMP(tempfilename, tmpfd);
STRCPY(lcl_ss_ctx->shadow_file, tempfilename);
/* Shadow file created. Any error below before the next cur_state assignment and a later call to ss_release will have
* to delete at least the shadow file apart from free'ing the malloc'ed snapshot context instance
*/
lcl_ss_ctx->cur_state = AFTER_SHADOW_FIL_CREAT;
if (FD_INVALID == tmpfd)
{
status = errno;
gtm_putmsg(VARLSTCNT(5) ERR_SSTMPCREATE, 2, tempdir_trans.len, tempdir_trans.addr, status);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
# ifdef __MVS__
if (-1 == gtm_zos_set_tag(tmpfd, TAG_BINARY, TAG_NOTTEXT, TAG_FORCE, &realfiletag))
TAG_POLICY_GTM_PUTMSG(tempfilename, realfiletag, TAG_BINARY, errno);
# endif
/* Temporary file for backup was created above using "mkstemp" which on AIX opens the file without
* large file support enabled. Work around that by closing the file descriptor returned and reopening
* the file with the "open" system call (which gets correctly translated to "open64"). We need to do
* this because the temporary file can get > 2GB. Since it is not clear if mkstemp on other Unix platforms
* will open the file for large file support, we use this solution for other Unix flavours as well.
*/
OPENFILE(tempfilename, O_RDWR, shdw_fd);
if (FD_INVALID == shdw_fd)
{
status = errno;
gtm_putmsg(VARLSTCNT(7) ERR_SSFILOPERR, 4, LEN_AND_LIT("open"),
tempdir_full.len, tempdir_full.addr, status);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
# ifdef __MVS__
if (-1 == gtm_zos_set_tag(shdw_fd, TAG_BINARY, TAG_NOTTEXT, TAG_FORCE, &realfiletag))
TAG_POLICY_GTM_PUTMSG(tempfilename, realfiletag, TAG_BINARY, errno);
# endif
/* Now that the temporary file has been opened successfully, close the fd returned by mkstemp */
F_CLOSE(tmpfd, fclose_res);
lcl_ss_ctx->shdw_fd = shdw_fd;
ENABLE_INTERRUPTS(INTRPT_IN_SS_INITIATE);
tempdir_full.len = STRLEN(tempdir_full.addr); /* update the length */
assert(GTM_PATH_MAX >= tempdir_full.len);
/* give temporary files the group and permissions as other shared resources - like journal files */
FSTAT_FILE(((unix_db_info *)(reg->dyn.addr->file_cntl->file_info))->fd, &stat_buf, fstat_res);
assert(-1 != fstat_res);
if (-1 != fstat_res)
{
/* Even though the temporary snapshot file is a physical file, we give it a relaxed IPC permissions to allow
* INTEG started by read-only processes to create snapshot files that are writable by processes having write
* permissions on the database file.
*/
if (gtm_set_group_and_perm(&stat_buf, &group_id, &perm, PERM_IPC, &pdd) < 0)
{
send_msg(VARLSTCNT(6+PERMGENDIAG_ARG_COUNT)
ERR_PERMGENFAIL, 4, RTS_ERROR_STRING("snapshot file"),
RTS_ERROR_STRING(((unix_db_info *)(reg->dyn.addr->file_cntl->file_info))->fn),
PERMGENDIAG_ARGS(pdd));
gtm_putmsg(VARLSTCNT(6+PERMGENDIAG_ARG_COUNT)
ERR_PERMGENFAIL, 4, RTS_ERROR_STRING("snapshot file"),
RTS_ERROR_STRING(((unix_db_info *)(reg->dyn.addr->file_cntl->file_info))->fn),
PERMGENDIAG_ARGS(pdd));
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
}
if ((-1 == fstat_res) || (-1 == FCHMOD(shdw_fd, perm))
|| ((-1 != group_id) && (-1 == fchown(shdw_fd, -1, group_id))))
{
status = errno;
gtm_putmsg(VARLSTCNT(8) ERR_SYSCALL, 5, LEN_AND_LIT("fchmod/fchown"), CALLFROM, status);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
if (debug_mupip)
{
util_out_print("!/MUPIP INFO: Successfully created the shadow file: !AD",
TRUE,
tempdir_full.len,
tempdir_full.addr);
}
/* STEP 3: Wait for kills-in-progress and initialize snapshot shadow file
*
* Snapshot Shadow File Layout -
*
* -----------------------
* | RESERVE_SHM_SPACE | <-- Variable sized space reserved in case we would like the snapshots to be preserved
* -----------------------
* | DB_FILE_HEADER | <-- Copy of the database file header taken at the snapshot time (in crit) (SGMNT_HDR_LEN)
* -----------------------
* | DB_MASTER_MAP | <-- MASTER_MAP_SIZE_MAX
* ----------------------- <-- offset of block zero
* | BLOCK_ZERO_BIMG | <-- csd->blk_size
* -----------------------
* | BLOCK_ONE_BIMG | <-- csd->blk_size
* -----------------------
* .
* .
* -----------------------
* | EOF_MARKER | <-- 512 bytes (DISK_BLOCK_SIZE)
* -----------------------
*/
/* Below, master map and the file header will be copied and hence check if we have the right
* pointers setup by the caller
*/
assert(NULL != util_ss_ptr);
assert(NULL != util_ss_ptr->master_map);
assert(NULL != util_ss_ptr->header);
grab_crit(reg);
INCR_INHIBIT_KILLS(cnl);
kip_pids_arr_ptr = cnl->kip_pid_array;
prev_ss_shmsize = 0;
for (retries = 0; MAX_TRY_FOR_TOT_BLKS >= retries; ++retries)
{
final_retry = (MAX_TRY_FOR_TOT_BLKS == retries);
/* On all but the 4th retry (inclusive of retries = -1), release crit */
if (!final_retry)
rel_crit(reg);
/*
* Outside crit (on the final retry, we will be holding crit while calculating the below):
* 1. total blocks
* 2. native size (total number of blocks in terms of DISK_BLOCK_SIZE)
* 3. write EOF an offset equal to the current database file size
* 4. create shared memory segment to be used as bitmap for storing whether a given database block
* was before imaged or not.
*/
DEFER_INTERRUPTS(INTRPT_IN_SS_INITIATE); /* Defer MUPIP STOP till the shared memory is created */
tot_blks = csd->trans_hist.total_blks;
prev_ss_shmsize = ss_shmsize;
ss_shmsize = (int)(ROUND_UP((SNAPSHOT_HDR_SIZE + TOT_BYTES_REQUIRED(tot_blks)), OS_PAGE_SIZE));
assert((0 == retries) || (0 != prev_ss_shmsize));
if (0 == retries)
{ /* If this is the first try, then create shared memory anyways. */
SS_INIT_SHM(ss_shmsize, ss_shmaddr, ss_shmid, FALSE, status);
} else if ((prev_ss_shmsize - SNAPSHOT_HDR_SIZE) < TOT_BYTES_REQUIRED(tot_blks))
{ /* Shared memory created with SS_INIT_SHM (in prior retries) is aligned at the OS page size boundary.
* So, in case of an extension (in subsequent retry) we check if the newly added blocks would fit in
* the existing shared memory (possible if the extra bytes allocated for OS page size alignment will
* be enough to hold the newly added database blocks). If not, remove the original shared memory and
* create a new one.
*/
if (debug_mupip)
{
util_out_print("!/MUPIP INFO: Existing shared memory !UL of size !UL not enough for total blocks \
!UL. Creating new shared memory", TRUE, ss_shmid, prev_ss_shmsize, tot_blks);
}
SS_INIT_SHM(ss_shmsize, ss_shmaddr, ss_shmid, TRUE, status);
}
if (status)
{ /* error while creating shared memory */
GET_CRIT_AND_DECR_INHIBIT_KILLS(reg, cnl);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
}
/* At this point, we are done with allocating shared memory (aligned with OS_PAGE_SIZE) enough to hold
* the total number of blocks. Any error below before the next cur_state assignment and a later call
* to ss_release will have to detach/rmid the shared memory identifier apart from deleting the shadow
* file and free'ing the malloc'ed snapshot context instance.
*/
lcl_ss_ctx->attach_shmid = ss_shmid;
lcl_ss_ctx->start_shmaddr = ss_shmaddr;
lcl_ss_ctx->cur_state = AFTER_SHM_CREAT;
ENABLE_INTERRUPTS(INTRPT_IN_SS_INITIATE);
if (debug_mupip)
{
util_out_print("!/MUPIP INFO: Shared memory created. SHMID = !UL",
TRUE,
ss_shmid);
}
/* Write EOF block in the snapshot file */
native_size = gds_file_size(reg->dyn.addr->file_cntl);
db_file_size = native_size * DISK_BLOCK_SIZE; /* Size of database file in bytes */
LSEEKWRITE(shdw_fd, ((off_t)db_file_size + ss_shmsize), eof_marker, EOF_MARKER_SIZE, status);
if (0 != status)
{ /* error while writing EOF record to snapshot file */
GET_CRIT_AND_DECR_INHIBIT_KILLS(reg, cnl);
ISSUE_WRITE_ERROR_AND_EXIT(reg, status, csa, tempfilename);
}
/* Wait for KIP to reset */
wait_for_zero_kip = csd->kill_in_prog;
/* Wait for existing kills-in-progress to be reset. Since a database file extension is possible as
* we don't hold crit while wcs_sleep below, we will retry if the total blocks have changed since
* we last checked it. However, in the final retry, the shared memory and shadow file initialization
* will happen in crit. Also, in the final retry, we won't be waiting for the kills in progress as
* we would be holding crit and cannot afford to wcs_sleep. So, in such a case, MUKILLIP should be
* issued by the caller of ss_initiate if csd->kill_in_prog is set to TRUE. But, such a case should
* be rare.
*/
for (crit_counter = 1; wait_for_zero_kip && !final_retry; )
{
/* Release crit before going into the wait loop */
rel_crit(reg);
if (debug_mupip)
{
GET_CUR_TIME;
util_out_print("!/MUPIP INFO: !AD : Start kill-in-prog wait for database !AD", TRUE,
CTIME_BEFORE_NL, time_ptr, DB_LEN_STR(reg));
}
while (csd->kill_in_prog && (MAX_CRIT_TRY > crit_counter++))
{
GET_C_STACK_FOR_KIP(kip_pids_arr_ptr, crit_counter, MAX_CRIT_TRY, 1, MAX_KIP_PID_SLOTS);
wcs_sleep(crit_counter);
}
if (debug_mupip)
{
GET_CUR_TIME;
util_out_print("!/MUPIP INFO: !AD : Done with kill-in-prog wait on !AD", TRUE,
CTIME_BEFORE_NL, time_ptr, DB_LEN_STR(reg));
}
wait_for_zero_kip = (MAX_CRIT_TRY > crit_counter); /* if TRUE, we can wait for some more time on
* this region */
grab_crit(reg);
if (csd->kill_in_prog)
{
/* It is possible for this to happen in case a concurrent GT.M process is in its 4th retry.
* In that case, it will not honor the inhibit_kills flag since it holds crit and therefore
* could have set kill-in-prog to a non-zero value while we were outside of crit.
* Since we have waited for 1 minute already, proceed with snapshot. The reasoning is that
* once the GT.M process that is in the final retry finishes off the second part of the M-kill,
* it will not start a new transaction in the first try which is outside of crit so will honor
* the inhibit-kills flag and therefore not increment the kill_in_prog counter any more until
* this crit is released. So we could be waiting for at most 1 kip increment per concurrent process
* that is updating the database. We expect these kills to be complete within 1 minute.
*/
if (!wait_for_zero_kip)
break;
} else
break;
}
grab_crit(reg);
/* There are two reasons why we might go for another iteration of this loop
* (a) After we have created the shared memory and before we grab crit, another process can add new blocks to the
* database, in which case csd->trans_hist.total_blks is no longer the value as we noted down above. Check if this
* is the case and if so, retry to obtain a consistent copy of the total number of blocks.
* (b) Similarly, csd->kill_in_prog was FALSE before grab_crit, but non-zero after grab-crit due to concurrency
* reasons. Check if this is the case and if so, retry to wait for KIP to reset.
*/
if ((tot_blks == csd->trans_hist.total_blks) && !csd->kill_in_prog)
{ /* We have a consistent copy of the total blocks and csd->kill_in_prog is FALSE inside crit. No need for
* retry.
*/
assert(native_size == (((gtm_uint64_t)tot_blks * (csd->blk_size / DISK_BLOCK_SIZE)) + (csd->start_vbn)));
break;
}
}
/* At this point, we are MOST likely guaranteed that kill-in-prog is set to zero for this region and CERTAINLY
* guaranteed that no more kills will be started for this region. Now, we are still holding crit, so any error
* that occurs henceforth should do a DECR_INHIBIT_KILLS and rel_crit before exiting to let the other processes
* proceed gracefully
*/
assert(csa->now_crit);
assert(native_size == (((gtm_uint64_t)tot_blks * (csd->blk_size / DISK_BLOCK_SIZE)) + (csd->start_vbn)));
assert(NULL != ss_shmaddr);
assert(0 == ((long)ss_shmaddr % OS_PAGE_SIZE));
assert(0 == ss_shmsize % OS_PAGE_SIZE);
assert(INVALID_SHMID != ss_shmid);
assert(0 == (ss_shmsize % DISK_BLOCK_SIZE));
ss_shm_vbn = ss_shmsize / DISK_BLOCK_SIZE; /* # of DISK_BLOCK_SIZEs the shared memory spans across */
assert(ss_shmid == lcl_ss_ctx->attach_shmid);
assert(AFTER_SHM_CREAT == lcl_ss_ctx->cur_state);
if (debug_mupip)
{
util_out_print("!/MUPIP INFO: Successfully created shared memory. SHMID = !UL",
TRUE,
ss_shmid);
}
/* It is possible that we did saw csd->full_upgraded TRUE before invoking ss_initiate but MUPIP SET -VER=V4 was done after
* ss_initiate was called. Handle appropriately.
*/
if (!csd->fully_upgraded)
{
/* If -ONLINE was specified explicitly, then it is an ERROR. Issue the error and return FALSE. */
if (online_specified)
{
gtm_putmsg(VARLSTCNT(4) ERR_SSV4NOALLOW, 2, DB_LEN_STR(reg));
util_out_print(NO_ONLINE_ERR_MSG, TRUE);
GET_CRIT_AND_DECR_INHIBIT_KILLS(reg, cnl);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return FALSE;
} else
{ /* If -ONLINE was assumed implicitly (default of INTEG -REG), then set ointeg_this_reg to FALSE,
* relinquish the resources and continue as if it is -NOONLINE
*/
ointeg_this_reg = FALSE;
assert(NULL != *ss_ctx);
ss_release(ss_ctx);
GET_CRIT_AND_DECR_INHIBIT_KILLS(reg, cnl);
UNFREEZE_REGION_IF_NEEDED(csd, reg);
return TRUE;
}
}
/* ===================== STEP 5: Flush the pending updates in the global cache =================== */
/* For a readonly database for the current process, we cannot do wcs_flu. We would have waited for the active queues
* to complete in mu_int_reg after doing a freeze. Now that we have crit, unfreeze the region
*/
if (reg->read_only)
{
region_freeze(reg, FALSE, FALSE, FALSE);
}
else if (!wcs_flu(WCSFLU_FLUSH_HDR | WCSFLU_WRITE_EPOCH | WCSFLU_MSYNC_DB)) /* wcs_flu guarantees that all the pending
* phase 2 commits are done with before returning */
{
assert(process_id != csd->freeze); /* We would not have frozen the region if the database is read-write */
gtm_putmsg(VARLSTCNT(6) ERR_BUFFLUFAILED, 4, LEN_AND_STR(calling_utility), DB_LEN_STR(reg));
GET_CRIT_AND_DECR_INHIBIT_KILLS(reg, cnl);
return FALSE;
}
assert(0 < cnl->num_snapshots_in_effect || (!SNAPSHOTS_IN_PROG(cnl)));
assert(csa->now_crit);
/* ========== STEP 6: Copy the file header, master map and the native file size into a private structure =========== */
memcpy(util_ss_ptr->header, csd, SGMNT_HDR_LEN);
memcpy(util_ss_ptr->master_map, MM_ADDR(csd), MASTER_MAP_SIZE(csd));
util_ss_ptr->native_size = native_size;
/* We are about to copy the process private variables to shared memory. Although we have done grab_crit above, we take
* snapshot crit lock to ensure that no other process attempts snapshot cleanup.
*/
DEFER_INTERRUPTS(INTRPT_IN_SS_INITIATE); /* Defer MUPIP STOP until we complete copying to shared memory */
/* == STEP 7: Populate snapshot context, database shared memory snapshot structure and snapshot file header structure == */
ss_shm_ptr = (shm_snapshot_ptr_t)SS_GETSTARTPTR(csa);
DBG_ENSURE_PTR_WITHIN_SS_BOUNDS(csa, (sm_uc_ptr_t)ss_shm_ptr);
/* Fill in the information for this snapshot in database shared memory */
ss_shm_ptr->ss_info.snapshot_tn = csd->trans_hist.curr_tn;
ss_shm_ptr->ss_info.free_blks = csd->trans_hist.free_blocks;
ss_shm_ptr->ss_info.total_blks = csd->trans_hist.total_blks;
ss_shm_ptr->ss_info.db_blk_size = csd->blk_size;
ss_shm_ptr->failure_errno = 0;
ss_shm_ptr->failed_pid = 0;
STRCPY(ss_shm_ptr->ss_info.shadow_file, tempfilename);
ss_shm_ptr->ss_info.shadow_vbn = ss_shm_vbn + csd->start_vbn;
ss_shm_ptr->ss_info.ss_shmid = cnl->ss_shmid = ss_shmid;
ss_shm_ptr->ss_info.ss_shmsize = ss_shmsize;
ss_shm_ptr->in_use = 1;
/* Fill in the information for the process specific snapshot context information */
lcl_ss_ctx->ss_shm_ptr = (shm_snapshot_ptr_t)(ss_shm_ptr);
lcl_ss_ctx->start_shmaddr = (sm_uc_ptr_t)ss_shmaddr;
lcl_ss_ctx->bitmap_addr = ((sm_uc_ptr_t)ss_shmaddr + SNAPSHOT_HDR_SIZE);
lcl_ss_ctx->shadow_vbn = ss_shm_ptr->ss_info.shadow_vbn;
lcl_ss_ctx->total_blks = ss_shm_ptr->ss_info.total_blks;
/* Fill snapshot file header information. This data will be persisted if -PRESERVE option is given */
ss_filhdr_ptr = (snapshot_filhdr_ptr_t)(ss_shmaddr);
FILL_SS_FILHDR_INFO(ss_shm_ptr, ss_filhdr_ptr)
ss_shm_ptr->preserve_snapshot = preserve_snapshot;
SET_LATCH_GLOBAL(&ss_shm_ptr->bitmap_latch, LOCK_AVAILABLE);
DECR_INHIBIT_KILLS(cnl);
/* announce GT.M that it's now ok to write the before images */
if (!SNAPSHOTS_IN_PROG(cnl))
SET_SNAPSHOTS_IN_PROG(cnl);
SET_SNAPSHOTS_IN_PROG(csa);
cnl->fastinteg_in_prog = muint_fast;
/* Having a write memory barrier here ensures that whenever GT.M reads a newer value of cnl->ss_shmcycle, it is guaranteed
* that the remaining fields that it reads from the shared memory will be the latest ones.
*/
SHM_WRITE_MEMORY_BARRIER;
cnl->ss_shmcycle++; /* indicate that the ss_shmid field of cnl is being reused */
lcl_ss_ctx->ss_shmcycle = cnl->ss_shmcycle;
rel_crit(reg);
if ((csa->onln_rlbk_cycle != csa->nl->onln_rlbk_cycle) || csa->nl->onln_rlbk_pid)
{ /* A concurrent online rollback happened since we did the gvcst_init. The INTEG is not reliable.
* Cleanup and exit
*/
gtm_putmsg(VARLSTCNT(1) ERR_DBROLLEDBACK);
UNFREEZE_REGION_IF_NEEDED(csa, reg);
return FALSE;
}
/* ============= STEP 8: Write the database file header and the master map =============
* Write the database file header at an offset equal to the database shared memory size.
* This is because if we want to preserve the snapshot then we would want to write the
* shared memory information at the beginning of the file. */
LSEEKWRITE(shdw_fd, (off_t)ss_shmsize, (sm_uc_ptr_t)util_ss_ptr->header, SGMNT_HDR_LEN, pwrite_res);
if (0 != pwrite_res)
ISSUE_WRITE_ERROR_AND_EXIT(reg, pwrite_res, csa, tempfilename);
dsk_addr += ((int)ss_shmsize + (int)SGMNT_HDR_LEN);
/* write the database master map to the shadow file */
assert(0 == ((dsk_addr + MASTER_MAP_SIZE_MAX) % OS_PAGE_SIZE));
LSEEKWRITE(shdw_fd, dsk_addr, (sm_uc_ptr_t)util_ss_ptr->master_map, MASTER_MAP_SIZE(csd), pwrite_res);
if (0 != pwrite_res)
ISSUE_WRITE_ERROR_AND_EXIT(reg, pwrite_res, csa, tempfilename);
/* The size of the master map written to snap-shot file is read from database header i.e. MASTER_MAP_SIZE(csd).
* That is the actual size which may differ depending on the version that created the database file.
* But this sets the dsk_addr for the Starting VBN using the current MASTER_MAP_SIZE_MAX to keep it aligned
* to the OS PAGE SIZE
*/
dsk_addr += MASTER_MAP_SIZE_MAX;
lcl_ss_ctx->cur_state = SNAPSHOT_INIT_DONE; /* Same as AFTER_SHM_CREAT but set for clarity of the snapshot state */
call_on_signal = NULL; /* Any further cleanup on signals will be taken care by gds_rundown */
ENABLE_INTERRUPTS(INTRPT_IN_SS_INITIATE);
assert(!ss_lock_held_by_us(reg)); /* We should never leave the function with the snapshot latch not being released */
return TRUE;
}
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