cache_rec_ptr_t db_csh_getn(block_id block)
{
cache_rec_ptr_t hdr, q0, start_cr, cr;
bt_rec_ptr_t bt;
unsigned int lcnt, ocnt;
int rip, max_ent, pass1, pass2, pass3;
int4 flsh_trigger;
uint4 r_epid, dummy;
sgmnt_addrs *csa;
sgmnt_data_ptr_t csd;
srch_blk_status *tp_srch_status;
error_def(ERR_BUFRDTIMEOUT);
error_def(ERR_INVALIDRIP);
csa = cs_addrs;
csd = csa->hdr;
assert(csa->now_crit);
assert(csa == &FILE_INFO(gv_cur_region)->s_addrs);
max_ent = csd->n_bts;
cr = (cache_rec_ptr_t)GDS_REL2ABS(csa->nl->cur_lru_cache_rec_off);
hdr = csa->acc_meth.bg.cache_state->cache_array + (block % csd->bt_buckets);
start_cr = csa->acc_meth.bg.cache_state->cache_array + csd->bt_buckets;
pass1 = max_ent; /* skip referred or dirty or read-into cache records */
pass2 = 2 * max_ent; /* skip referred cache records */
pass3 = 3 * max_ent; /* skip nothing */
INCR_DB_CSH_COUNTER(csa, n_db_csh_getns, 1);
for (lcnt = 0; ; lcnt++)
{
if (lcnt > pass3)
{
BG_TRACE_PRO(wc_blocked_db_csh_getn_loopexceed);
assert(FALSE);
break;
}
cr++;
if (cr == start_cr + max_ent)
cr = start_cr;
VMS_ONLY(
if ((lcnt == pass1) || (lcnt == pass2))
wcs_wtfini(gv_cur_region);
)
if (TRUE == cr->refer && lcnt < pass2)
{ /* in passes 1 & 2, set refer to FALSE and skip; in the third pass attempt reuse even if TRUE == refer */
cr->refer = FALSE;
continue;
}
if (TRUE == cr->in_cw_set)
{ /* this process already owns it - skip it */
cr->refer = TRUE;
continue;
}
if (CDB_STAGNATE <= t_tries || mu_reorg_process)
{
/* Prevent stepping on self when crit for entire transaction.
* This is done by looking up in sgm_info_ptr->blk_in_use and cw_stagnate for presence of the block.
* The following two hashtable lookups are not similar, since in TP, sgm_info_ptr->blks_in_use
* is updated to the latest cw_stagnate list of blocks only in tp_hist().
* Also note that the lookup in sgm_info_ptr->blks_in_use reuses blocks that don't have cse's.
* This is to allow big-read TP transactions which may use up more than the available global buffers.
* There is one issue here in that a block that has been only read till now may be stepped upon here
* but may later be needed for update. It is handled by updating the block's corresponding
* entry in the set of histories (sgm_info_ptr->first_tp_hist[index] structure) to hold the
* "cr" and "cycle" of the t_qread done for the block when it was intended to be changed for the
* first time within the transaction since otherwise the transaction would restart due to a
* cdb_sc_lostcr status. Note that "tn" (read_tn of the block) in the first_tp_hist will still
* remain the "tn" when the block was first read within this transaction to ensure the block
* hasn't been modified since the start of the transaction. Once we intend on changing the
* block i.e. srch_blk_status->ptr is non-NULL, we ensure in the code below not to step on it.
* [tp_hist() is the routine that updates the "cr", "cycle" and "tn" of the block].
* Note that usually in a transaction the first_tp_hist[] structure holds the "cr", "cycle", and "tn"
* of the first t_qread of the block within that transaction. The above is the only exception.
* Also note that for blocks in cw_stagnate (i.e. current TP mini-action), we don't reuse any of
* them even if they don't have a cse. This is to ensure that the current action doesn't
* encounter a restart due to cdb_sc_lostcr in tp_hist() even in the fourth-retry.
*/
if (dollar_tlevel
&& (tp_srch_status =
(srch_blk_status *)lookup_hashtab_ent(sgm_info_ptr->blks_in_use, (void *)cr->blk, &dummy))
&& tp_srch_status->ptr)
{ /* this process is already using the block - skip it */
cr->refer = TRUE;
continue;
}
if (NULL != lookup_hashtab_ent(cw_stagnate, (void *)cr->blk, &dummy))
{
cr->refer = TRUE;
continue;
}
}
if (cr->dirty)
{ /* Note that in Unix, it is possible that we see a stale value of cr->dirty (possible if a
* concurrent wcs_wtstart() has reset dirty to 0 but that update did not reach us yet). In this
* case the call to wcs_get_space() below will do the necessary memory barrier instructions
* (through calls to aswp()) which will allow us to see the non-stale value of cr->dirty.
*
* It is also possible that cr->dirty is non-zero but < cr->flushed_dirty_tn. In this case, wcs_get_space
* done below will return FALSE forcing a cache-rebuild which will fix this situation.
*
* In VMS, another process cannot be concurrently resetting cr->dirty to 0 as the resetting routine
* is wcs_wtfini() which is executed in crit which another process cannot be in as we are in crit now.
*/
if (gv_cur_region->read_only)
continue;
if (lcnt < pass1)
{
if (!csa->timer && (csa->nl->wcs_timers < 1))
wcs_timer_start(gv_cur_region, FALSE);
continue;
}
BG_TRACE_PRO(db_csh_getn_flush_dirty);
if (FALSE == wcs_get_space(gv_cur_region, 0, cr))
{ /* failed to flush it out - force a rebuild */
BG_TRACE_PRO(wc_blocked_db_csh_getn_wcsstarvewrt);
assert(FALSE);
break;
}
assert(0 == cr->dirty);
}
UNIX_ONLY(
/* the cache-record is not free for reuse until the write-latch value becomes LATCH_CLEAR.
* In VMS, resetting the write-latch value occurs in wcs_wtfini() which is in CRIT, we are fine.
* In Unix, this resetting is done by wcs_wtstart() which is out-of-crit. Therefore, we need to
* wait for this value to be LATCH_CLEAR before reusing this cache-record.
* Note that we are examining the write-latch-value without holding the interlock. It is ok to do
* this because the only two routines that modify the latch value are bg_update() and
* wcs_wtstart(). The former cannot be concurrently executing because we are in crit.
* The latter will not update the latch value unless this cache-record is dirty. But in this
* case we would have most likely gone through the if (cr->dirty) check above. Most likely
* because there is one rare possibility where a concurrent wcs_wtstart() has set cr->dirty
* to 0 but not yet cleared the latch. In that case we wait for the latch to be cleared.
* In all other cases, nobody is modifying the latch since when we got crit and therefore
* it is safe to observe the value of the latch without holding the interlock.
*/
if (LATCH_CLEAR != WRITE_LATCH_VAL(cr))
{ /* possible if a concurrent wcs_wtstart() has set cr->dirty to 0 but not yet
* cleared the latch. this should be very rare though.
*/
if (lcnt < pass2)
continue; /* try to find some other cache-record to reuse until the 3rd pass */
for (ocnt = 1; (MAXWRTLATCHWAIT >= ocnt) && (LATCH_CLEAR != WRITE_LATCH_VAL(cr)); ocnt++)
wcs_sleep(SLEEP_WRTLATCHWAIT); /* since it is a short lock, sleep the minimum */
if (MAXWRTLATCHWAIT <= ocnt)
{
BG_TRACE_PRO(db_csh_getn_wrt_latch_stuck);
assert(FALSE);
continue;
}
}
)
sm_uc_ptr_t t_qread(block_id blk, sm_int_ptr_t cycle, cache_rec_ptr_ptr_t cr_out)
/* cycle is used in t_end to detect if the buffer has been refreshed since the t_qread */
{
int4 status;
uint4 blocking_pid;
cache_rec_ptr_t cr;
bt_rec_ptr_t bt;
boolean_t clustered, hold_onto_crit, was_crit;
int dummy, lcnt, ocnt;
cw_set_element *cse;
off_chain chain1;
register sgmnt_addrs *csa;
register sgmnt_data_ptr_t csd;
enum db_ver ondsk_blkver;
int4 dummy_errno;
boolean_t already_built, is_mm, reset_first_tp_srch_status, set_wc_blocked, sleep_invoked;
ht_ent_int4 *tabent;
srch_blk_status *blkhist;
trans_num dirty, blkhdrtn;
sm_uc_ptr_t buffaddr;
uint4 stuck_cnt = 0;
boolean_t lcl_blk_free;
node_local_ptr_t cnl;
lcl_blk_free = block_is_free;
block_is_free = FALSE; /* Reset to FALSE so that if t_qread fails below, we don't have an incorrect state of this var */
first_tp_srch_status = NULL;
reset_first_tp_srch_status = FALSE;
csa = cs_addrs;
csd = csa->hdr;
INCR_DB_CSH_COUNTER(csa, n_t_qreads, 1);
is_mm = (dba_mm == csd->acc_meth);
/* We better hold crit in the final retry (TP & non-TP). Only exception is journal recovery */
assert((t_tries < CDB_STAGNATE) || csa->now_crit || mupip_jnl_recover);
if (dollar_tlevel)
{
assert(sgm_info_ptr);
if (0 != sgm_info_ptr->cw_set_depth)
{
chain1 = *(off_chain *)&blk;
if (1 == chain1.flag)
{
assert(sgm_info_ptr->cw_set_depth);
if ((int)chain1.cw_index < sgm_info_ptr->cw_set_depth)
tp_get_cw(sgm_info_ptr->first_cw_set, (int)chain1.cw_index, &cse);
else
{
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
} else
{
if (NULL != (tabent = lookup_hashtab_int4(sgm_info_ptr->blks_in_use, (uint4 *)&blk)))
first_tp_srch_status = tabent->value;
else
first_tp_srch_status = NULL;
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
cse = first_tp_srch_status ? first_tp_srch_status->cse : NULL;
}
assert(!cse || !cse->high_tlevel);
assert(!chain1.flag || cse);
if (cse)
{ /* transaction has modified the sought after block */
if ((gds_t_committed != cse->mode) || (n_gds_t_op < cse->old_mode))
{ /* Changes have not been committed to shared memory, i.e. still in private memory.
* Build block in private buffer if not already done and return the same.
*/
assert(gds_t_writemap != cse->mode);
if (FALSE == cse->done)
{ /* out of date, so make it current */
assert(gds_t_committed != cse->mode);
already_built = (NULL != cse->new_buff);
/* Validate the block's search history right after building a private copy.
* This is not needed in case gvcst_search is going to reuse the clue's search
* history and return (because tp_hist will do the validation of this block).
* But if gvcst_search decides to do a fresh traversal (because the clue does not
* cover the path of the current input key etc.) the block build that happened now
* will not get validated in tp_hist since it will instead be given the current
* key's search history path (a totally new path) for validation. Since a private
* copy of the block has been built, tp_tend would also skip validating this block
* so it is necessary that we validate the block right here. Since it is tricky to
* accurately differentiate between the two cases, we do the validation
* unconditionally here (besides it is only a few if checks done per block build
* so it is considered okay performance-wise).
*/
gvcst_blk_build(cse, (uchar_ptr_t)cse->new_buff, 0);
assert(NULL != cse->blk_target);
if (!already_built && !chain1.flag)
{
buffaddr = first_tp_srch_status->buffaddr;
cr = first_tp_srch_status->cr;
assert((is_mm || cr) && buffaddr);
blkhdrtn = ((blk_hdr_ptr_t)buffaddr)->tn;
if (TP_IS_CDB_SC_BLKMOD3(cr, first_tp_srch_status, blkhdrtn))
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_blkmod; /* should this be something else */
TP_TRACE_HIST_MOD(blk, gv_target, tp_blkmod_t_qread, cs_data,
first_tp_srch_status->tn, blkhdrtn,
((blk_hdr_ptr_t)buffaddr)->levl);
return (sm_uc_ptr_t)NULL;
}
if (!is_mm && ((first_tp_srch_status->cycle != cr->cycle)
|| (first_tp_srch_status->blk_num != cr->blk)))
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_lostcr; /* should this be something else */
return (sm_uc_ptr_t)NULL;
}
}
cse->done = TRUE;
}
*cycle = CYCLE_PVT_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)cse->new_buff;
} else
{ /* Block changes are already committed to shared memory (possible if we are in TP
* in the 2nd phase of M-Kill in gvcst_expand_free_subtree.c). In this case, read
* block from shared memory; do not look at private memory (i.e. cse) as that might
* not be as uptodate as shared memory.
*/
assert(csa->now_crit); /* gvcst_expand_free_subtree does t_qread in crit */
/* If this block was newly created as part of the TP transaction, it should not be killed
* as part of the 2nd phase of M-kill. This is because otherwise the block's cse would
* have had an old_mode of kill_t_create in which case we would not have come into this
* else block. Assert accordingly.
*/
assert(!chain1.flag);
first_tp_srch_status = NULL; /* do not use any previous srch_hist information */
}
}
} else
{
if (NULL != (tabent = lookup_hashtab_int4(sgm_info_ptr->blks_in_use, (uint4 *)&blk)))
first_tp_srch_status = tabent->value;
else
first_tp_srch_status = NULL;
}
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
if (!is_mm && first_tp_srch_status)
{
cr = first_tp_srch_status->cr;
assert(cr && !first_tp_srch_status->cse);
if (first_tp_srch_status->cycle == cr->cycle)
{
*cycle = first_tp_srch_status->cycle;
*cr_out = cr;
cr->refer = TRUE;
if (CDB_STAGNATE <= t_tries) /* mu_reorg doesn't use TP else should have an || for that */
CWS_INSERT(blk);
return (sm_uc_ptr_t)first_tp_srch_status->buffaddr;
} else
{ /* Block was already part of the read-set of this transaction, but got recycled in the cache.
* Allow block recycling by resetting first_tp_srch_status for this blk to reflect the new
* buffer, cycle and cache-record. tp_hist (invoked much later) has validation checks to detect
* if block recycling happened within the same mini-action and restart in that case.
* Updating first_tp_srch_status has to wait until the end of t_qread since only then do we know
* the values to update to. Set a variable that will enable the updation before returning.
* Also assert that if we are in the final retry, we are never in a situation where we have a
* block that got recycled since the start of the current mini-action. This is easily detected since
* as part of the final retry we maintain a hash-table "cw_stagnate" that holds the blocks that
* have been read as part of the current mini-action until now.
*/
assert(CDB_STAGNATE > t_tries || (NULL == lookup_hashtab_int4(&cw_stagnate, (uint4 *)&blk)));
reset_first_tp_srch_status = TRUE;
}
}
}
if ((blk >= csa->ti->total_blks) || (blk < 0))
{ /* requested block out of range; could occur because of a concurrency conflict */
if ((&FILE_INFO(gv_cur_region)->s_addrs != csa) || (csd != cs_data))
GTMASSERT;
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
if (is_mm)
{
*cycle = CYCLE_SHRD_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)(mm_read(blk));
}
# ifdef GTM_CRYPT
/* If database is encrypted, check if encryption initialization went fine for this database. If not,
* do not let process proceed as it could now potentially get a peek at the desired data from the
* decrypted shared memory global buffers (read in from disk by other processes) without having to go to disk.
* If DSE, allow for a special case where it is trying to dump a local bitmap block. In this case, DSE
* can continue to run fine (even if encryption initialization failed) since bitmap blocks are unencrypted.
*/
if (csa->encrypt_init_status && (!dse_running || !IS_BITMAP_BLK(blk)))
GC_RTS_ERROR(csa->encrypt_init_status, gv_cur_region->dyn.addr->fname);
# endif
assert(dba_bg == csd->acc_meth);
assert(!first_tp_srch_status || !first_tp_srch_status->cr
|| first_tp_srch_status->cycle != first_tp_srch_status->cr->cycle);
if (FALSE == (clustered = csd->clustered))
bt = NULL;
was_crit = csa->now_crit;
ocnt = 0;
cnl = csa->nl;
set_wc_blocked = FALSE; /* to indicate whether cnl->wc_blocked was set to TRUE by us */
hold_onto_crit = csa->hold_onto_crit; /* note down in local to avoid csa-> dereference in multiple usages below */
do
{
if (NULL == (cr = db_csh_get(blk)))
{ /* not in memory */
if (clustered && (NULL != (bt = bt_get(blk))) && (FALSE == bt->flushing))
bt = NULL;
if (!csa->now_crit)
{
assert(!hold_onto_crit);
if (NULL != bt)
{ /* at this point, bt is not NULL only if clustered and flushing - wait no crit */
assert(clustered);
wait_for_block_flush(bt, blk); /* try for no other node currently writing the block */
}
if ((csd->flush_trigger <= cnl->wcs_active_lvl) && (FALSE == gv_cur_region->read_only))
JNL_ENSURE_OPEN_WCS_WTSTART(csa, gv_cur_region, 0, dummy_errno);
/* a macro that dclast's "wcs_wtstart" and checks for errors etc. */
grab_crit(gv_cur_region);
cr = db_csh_get(blk); /* in case blk arrived before crit */
}
if (clustered && (NULL != (bt = bt_get(blk))) && (TRUE == bt->flushing))
{ /* Once crit, need to assure that if clustered, that flushing is [still] complete
* If it isn't, we missed an entire WM cycle and have to wait for another node to finish */
wait_for_block_flush(bt, blk); /* ensure no other node currently writing the block */
}
if (NULL == cr)
{ /* really not in memory - must get a new buffer */
assert(csa->now_crit);
cr = db_csh_getn(blk);
if (CR_NOTVALID == (sm_long_t)cr)
{
assert(cnl->wc_blocked); /* only reason we currently know wcs_get_space could fail */
assert(gtm_white_box_test_case_enabled);
SET_TRACEABLE_VAR(cnl->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_db_csh_getn_invalid_blk);
set_wc_blocked = TRUE;
break;
}
assert(0 <= cr->read_in_progress);
*cycle = cr->cycle;
cr->tn = csd->trans_hist.curr_tn;
/* Record history of most recent disk reads only in dbg builds for now. Although the macro
* is just a couple dozen instructions, it is done while holding crit so we want to avoid
* delaying crit unless really necessary. Whoever wants this information can enable it
* by a build change to remove the DEBUG_ONLY part below.
*/
DEBUG_ONLY(DSKREAD_TRACE(csa, GDS_ANY_ABS2REL(csa,cr), cr->tn, process_id, blk, cr->cycle);)
if (!was_crit && !hold_onto_crit)
rel_crit(gv_cur_region);
/* read outside of crit may be of a stale block but should be detected by t_end or tp_tend */
assert(0 == cr->dirty);
assert(cr->read_in_progress >= 0);
CR_BUFFER_CHECK(gv_cur_region, csa, csd, cr);
if (SS_NORMAL != (status = dsk_read(blk, GDS_REL2ABS(cr->buffaddr), &ondsk_blkver, lcl_blk_free)))
{ /* buffer does not contain valid data, so reset blk to be empty */
cr->cycle++; /* increment cycle for blk number changes (for tp_hist and others) */
cr->blk = CR_BLKEMPTY;
cr->r_epid = 0;
RELEASE_BUFF_READ_LOCK(cr);
assert(-1 <= cr->read_in_progress);
assert(was_crit == csa->now_crit);
if (FUTURE_READ == status)
{ /* in cluster, block can be in the "future" with respect to the local history */
assert(TRUE == clustered);
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_future_read; /* t_retry forces the history up to date */
return (sm_uc_ptr_t)NULL;
}
if (ERR_DYNUPGRDFAIL == status)
{ /* if we dont hold crit on the region, it is possible due to concurrency conflicts
* that this block is unused (i.e. marked free/recycled in bitmap, see comments in
* gds_blk_upgrade.h). in this case we should not error out but instead restart.
*/
if (was_crit)
{
assert(FALSE);
rts_error(VARLSTCNT(5) status, 3, blk, DB_LEN_STR(gv_cur_region));
} else
{
rdfail_detail = cdb_sc_lostcr;
return (sm_uc_ptr_t)NULL;
}
}
if (-1 == status)
{
/* could have been concurrent truncate, and we read a blk >= csa->ti->total_blks */
/* restart */
rdfail_detail = cdb_sc_truncate;
return (sm_uc_ptr_t)NULL;
} else
rts_error(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(gv_cur_region), status);
}
disk_blk_read = TRUE;
assert(0 <= cr->read_in_progress);
assert(0 == cr->dirty);
/* Only set in cache if read was success */
cr->ondsk_blkver = (lcl_blk_free ? GDSVCURR : ondsk_blkver);
cr->r_epid = 0;
RELEASE_BUFF_READ_LOCK(cr);
assert(-1 <= cr->read_in_progress);
*cr_out = cr;
assert(was_crit == csa->now_crit);
if (reset_first_tp_srch_status)
{ /* keep the parantheses for the if (although single line) since the following is a macro */
RESET_FIRST_TP_SRCH_STATUS(first_tp_srch_status, cr, *cycle);
}
return (sm_uc_ptr_t)GDS_REL2ABS(cr->buffaddr);
} else if (!was_crit && (BAD_LUCK_ABOUNDS > ocnt))
{
assert(!hold_onto_crit);
assert(TRUE == csa->now_crit);
assert(cnl->in_crit == process_id);
rel_crit(gv_cur_region);
}
}
sm_uc_ptr_t t_qread(block_id blk, sm_int_ptr_t cycle, cache_rec_ptr_ptr_t cr_out)
/* cycle is used in t_end to detect if the buffer has been refreshed since the t_qread */
{
uint4 status, duint4, blocking_pid;
cache_rec_ptr_t cr;
bt_rec_ptr_t bt;
bool clustered, was_crit;
int dummy, lcnt, ocnt;
cw_set_element *cse;
off_chain chain1;
register sgmnt_addrs *csa;
register sgmnt_data_ptr_t csd;
int4 dummy_errno;
boolean_t already_built, is_mm, reset_first_tp_srch_status, set_wc_blocked;
error_def(ERR_DBFILERR);
error_def(ERR_BUFOWNERSTUCK);
first_tp_srch_status = NULL;
reset_first_tp_srch_status = FALSE;
csa = cs_addrs;
csd = csa->hdr;
INCR_DB_CSH_COUNTER(csa, n_t_qreads, 1);
is_mm = (dba_mm == csd->acc_meth);
assert((t_tries < CDB_STAGNATE) || csa->now_crit);
if (0 < dollar_tlevel)
{
assert(sgm_info_ptr);
if (0 != sgm_info_ptr->cw_set_depth)
{
chain1 = *(off_chain *)&blk;
if (1 == chain1.flag)
{
assert(sgm_info_ptr->cw_set_depth);
if ((int)chain1.cw_index < sgm_info_ptr->cw_set_depth)
tp_get_cw(sgm_info_ptr->first_cw_set, (int)chain1.cw_index, &cse);
else
{
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
} else
{
first_tp_srch_status = (srch_blk_status *)lookup_hashtab_ent(sgm_info_ptr->blks_in_use,
(void *)blk, &duint4);
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
cse = first_tp_srch_status ? first_tp_srch_status->ptr : NULL;
}
assert(!cse || !cse->high_tlevel);
if (cse)
{ /* transaction has modified the sought after block */
assert(gds_t_writemap != cse->mode);
if (FALSE == cse->done)
{ /* out of date, so make it current */
already_built = (NULL != cse->new_buff);
gvcst_blk_build(cse, (uchar_ptr_t)cse->new_buff, 0);
assert(cse->blk_target);
if (!already_built && !chain1.flag)
{
assert(first_tp_srch_status && (is_mm || first_tp_srch_status->cr)
&& first_tp_srch_status->buffaddr);
if (first_tp_srch_status->tn <=
((blk_hdr_ptr_t)(first_tp_srch_status->buffaddr))->tn)
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_blkmod; /* should this be something else */
TP_TRACE_HIST_MOD(blk, gv_target, tp_blkmod_t_qread, cs_data,
first_tp_srch_status->tn,
((blk_hdr_ptr_t)(first_tp_srch_status->buffaddr))->tn,
((blk_hdr_ptr_t)(first_tp_srch_status->buffaddr))->levl);
return (sm_uc_ptr_t)NULL;
}
if ((!is_mm) && (first_tp_srch_status->cycle != first_tp_srch_status->cr->cycle
|| first_tp_srch_status->blk_num != first_tp_srch_status->cr->blk))
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_lostcr; /* should this be something else */
return (sm_uc_ptr_t)NULL;
}
if (certify_all_blocks &&
FALSE == cert_blk(gv_cur_region, blk, (blk_hdr_ptr_t)cse->new_buff,
cse->blk_target->root))
GTMASSERT;
}
cse->done = TRUE;
}
*cycle = CYCLE_PVT_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)cse->new_buff;
}
assert(!chain1.flag);
} else
first_tp_srch_status =
(srch_blk_status *)lookup_hashtab_ent(sgm_info_ptr->blks_in_use, (void *)blk, &duint4);
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
if (!is_mm && first_tp_srch_status)
{
assert(first_tp_srch_status->cr && !first_tp_srch_status->ptr);
if (first_tp_srch_status->cycle == first_tp_srch_status->cr->cycle)
{
*cycle = first_tp_srch_status->cycle;
*cr_out = first_tp_srch_status->cr;
first_tp_srch_status->cr->refer = TRUE;
if (CDB_STAGNATE <= t_tries) /* mu_reorg doesn't use TP else should have an || for that */
CWS_INSERT(blk);
return (sm_uc_ptr_t)first_tp_srch_status->buffaddr;
} else
{ /* Block was already part of the read-set of this transaction, but got recycled. Allow for
* recycling. But update the first_tp_srch_status (for this blk) in the si->first_tp_hist
* array to reflect the new buffer, cycle and cache-record. Since we know those only at the end of
* t_qread, set a variable here that will enable the updation before returning from t_qread().
*/
reset_first_tp_srch_status = TRUE;
}
}
}
if ((blk >= csa->ti->total_blks) || (blk < 0))
{ /* requested block out of range; could occur because of a concurrency conflict */
if ((&FILE_INFO(gv_cur_region)->s_addrs != csa) || (csd != cs_data))
GTMASSERT;
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
if (is_mm)
{
*cycle = CYCLE_SHRD_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)(mm_read(blk));
}
assert(dba_bg == csd->acc_meth);
assert(!first_tp_srch_status || !first_tp_srch_status->cr
|| first_tp_srch_status->cycle != first_tp_srch_status->cr->cycle);
if (FALSE == (clustered = csd->clustered))
bt = NULL;
was_crit = csa->now_crit;
ocnt = 0;
set_wc_blocked = FALSE; /* to indicate whether csd->wc_blocked was set to TRUE by us */
do
{
if (NULL == (cr = db_csh_get(blk)))
{ /* not in memory */
if (clustered && (NULL != (bt = bt_get(blk))) && (FALSE == bt->flushing))
bt = NULL;
if (FALSE == csa->now_crit)
{
if (NULL != bt)
{ /* at this point, bt is not NULL only if clustered and flushing - wait no crit */
assert(clustered);
wait_for_block_flush(bt, blk); /* try for no other node currently writing the block */
}
if (csd->flush_trigger <= csa->nl->wcs_active_lvl && FALSE == gv_cur_region->read_only)
JNL_ENSURE_OPEN_WCS_WTSTART(csa, gv_cur_region, 0, dummy_errno);
/* a macro that dclast's wcs_wtstart() and checks for errors etc. */
grab_crit(gv_cur_region);
cr = db_csh_get(blk); /* in case blk arrived before crit */
}
if (clustered && (NULL != (bt = bt_get(blk))) && (TRUE == bt->flushing))
{ /* Once crit, need to assure that if clustered, that flushing is [still] complete
* If it isn't, we missed an entire WM cycle and have to wait for another node to finish */
wait_for_block_flush(bt, blk); /* ensure no other node currently writing the block */
}
if (NULL == cr)
{ /* really not in memory - must get a new buffer */
assert(csa->now_crit);
cr = db_csh_getn(blk);
if (CR_NOTVALID == (sm_long_t)cr)
{
SET_TRACEABLE_VAR(cs_data->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_db_csh_getn_invalid_blk);
set_wc_blocked = TRUE;
break;
}
assert(0 <= cr->read_in_progress);
*cycle = cr->cycle;
cr->tn = csa->ti->curr_tn;
if (FALSE == was_crit)
rel_crit(gv_cur_region);
/* read outside of crit may be of a stale block but should be detected by t_end or tp_tend */
assert(0 == cr->dirty);
assert(cr->read_in_progress >= 0);
INCR_DB_CSH_COUNTER(csa, n_dsk_reads, 1);
if (SS_NORMAL != (status = dsk_read(blk, GDS_REL2ABS(cr->buffaddr))))
{
RELEASE_BUFF_READ_LOCK(cr);
assert(was_crit == csa->now_crit);
if (FUTURE_READ == status)
{ /* in cluster, block can be in the "future" with respect to the local history */
assert(TRUE == clustered);
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_future_read; /* t_retry forces the history up to date */
return (sm_uc_ptr_t)NULL;
}
rts_error(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(gv_cur_region), status);
}
assert(0 <= cr->read_in_progress);
assert(0 == cr->dirty);
cr->r_epid = 0;
RELEASE_BUFF_READ_LOCK(cr);
assert(-1 <= cr->read_in_progress);
*cr_out = cr;
assert(was_crit == csa->now_crit);
if (reset_first_tp_srch_status)
{ /* keep the parantheses for the if (although single line) since the following is a macro */
RESET_FIRST_TP_SRCH_STATUS(first_tp_srch_status, cr, *cycle);
}
return (sm_uc_ptr_t)GDS_REL2ABS(cr->buffaddr);
} else if ((FALSE == was_crit) && (BAD_LUCK_ABOUNDS > ocnt))
{
assert(TRUE == csa->now_crit);
assert(csa->nl->in_crit == process_id);
rel_crit(gv_cur_region);
}
}
if (CR_NOTVALID == (sm_long_t)cr)
{
SET_TRACEABLE_VAR(cs_data->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_db_csh_get_invalid_blk);
set_wc_blocked = TRUE;
break;
}
for (lcnt = 1; ; lcnt++)
{
if (0 > cr->read_in_progress)
{ /* it's not being read */
if (clustered && (0 == cr->bt_index) &&
(cr->tn < ((th_rec *)((uchar_ptr_t)csa->th_base + csa->th_base->tnque.fl))->tn))
{ /* can't rely on the buffer */
cr->cycle++; /* increment cycle whenever blk number changes (tp_hist depends on this) */
cr->blk = CR_BLKEMPTY;
break;
}
*cycle = cr->cycle;
*cr_out = cr;
VMS_ONLY(
/* If we were doing the db_csh_get() above (in t_qread itself) and located the cache-record
* which, before coming here and taking a copy of cr->cycle a few lines above, was made an
* older twin by another process in bg_update (note this can happen in VMS only) which has
* already incremented the cycle, we will end up having a copy of the old cache-record with
* its incremented cycle number and hence will succeed in tp_hist validation if we return
* this <cr,cycle> combination although we don't want to since this "cr" is not current for
* the given block as of now. Note that the "indexmod" optimization in tp_tend() relies on
* an accurate intermediate validation by tp_hist() which in turn relies on the <cr,cycle>
* value returned by t_qread() to be accurate for a given blk at the current point in time.
* We detect the older-twin case by the following check. Note that here we depend on the
* the fact that bg_update() sets cr->bt_index to 0 before incrementing cr->cycle.
* Given that order, cr->bt_index can be guaranteed to be 0 if we read the incremented cycle
*/
if (cr->twin && (0 == cr->bt_index))
break;
)
if (cr->blk != blk)
break;
if (was_crit != csa->now_crit)
rel_crit(gv_cur_region);
assert(was_crit == csa->now_crit);
if (reset_first_tp_srch_status)
{ /* keep the parantheses for the if (although single line) since the following is a macro */
RESET_FIRST_TP_SRCH_STATUS(first_tp_srch_status, cr, *cycle);
}
/* Note that at this point we expect t_qread() to return a <cr,cycle> combination that
* corresponds to "blk" passed in. It is crucial to get an accurate value for both the fields
* since tp_hist() relies on this for its intermediate validation.
*/
return (sm_uc_ptr_t)GDS_ANY_REL2ABS(csa, cr->buffaddr);
}
if (blk != cr->blk)
break;
if (lcnt >= BUF_OWNER_STUCK && (0 == (lcnt % BUF_OWNER_STUCK)))
{
if (FALSE == csa->now_crit)
grab_crit(gv_cur_region);
if (cr->read_in_progress < -1)
{ /* outside of design; clear to known state */
BG_TRACE_PRO(t_qread_out_of_design);
INTERLOCK_INIT(cr);
assert(0 == cr->r_epid);
cr->r_epid = 0;
} else if (cr->read_in_progress >= 0)
{
BG_TRACE_PRO(t_qread_buf_owner_stuck);
if (0 != (blocking_pid = cr->r_epid))
{
if (FALSE == is_proc_alive(blocking_pid, cr->image_count))
{ /* process gone: release that process's lock */
assert(0 == cr->bt_index);
if (cr->bt_index)
{
SET_TRACEABLE_VAR(csd->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_bad_bt_index1);
set_wc_blocked = TRUE;
break;
}
cr->cycle++; /* increment cycle for blk number changes (for tp_hist) */
cr->blk = CR_BLKEMPTY;
RELEASE_BUFF_READ_LOCK(cr);
} else
{
rel_crit(gv_cur_region);
send_msg(VARLSTCNT(4) ERR_DBFILERR, 2, DB_LEN_STR(gv_cur_region));
send_msg(VARLSTCNT(9) ERR_BUFOWNERSTUCK, 7, process_id, blocking_pid,
cr->blk, cr->blk, (lcnt / BUF_OWNER_STUCK),
cr->read_in_progress, cr->rip_latch.latch_pid);
if ((4 * BUF_OWNER_STUCK) <= lcnt)
GTMASSERT;
/* Kickstart the process taking a long time in case it was suspended */
UNIX_ONLY(continue_proc(blocking_pid));
}
} else
{ /* process stopped before could set r_epid */
assert(0 == cr->bt_index);
if (cr->bt_index)
{
SET_TRACEABLE_VAR(csd->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_bad_bt_index2);
set_wc_blocked = TRUE;
break;
}
cr->cycle++; /* increment cycle for blk number changes (for tp_hist) */
cr->blk = CR_BLKEMPTY;
RELEASE_BUFF_READ_LOCK(cr);
if (cr->read_in_progress < -1) /* race: process released since if r_epid */
LOCK_BUFF_FOR_READ(cr, dummy);
}
}
if (was_crit != csa->now_crit)
rel_crit(gv_cur_region);
} else
wcs_sleep(lcnt);
}
if (set_wc_blocked) /* cannot use csd->wc_blocked here as we might not necessarily have crit */
break;
ocnt++;
if (BAD_LUCK_ABOUNDS <= ocnt)
{
if (BAD_LUCK_ABOUNDS < ocnt || csa->now_crit)
{
rel_crit(gv_cur_region);
GTMASSERT;
}
if (FALSE == csa->now_crit)
grab_crit(gv_cur_region);
}
} while (TRUE);
enum cdb_sc gvcst_search(gv_key *pKey, /* Key to search for */
srch_hist *pHist) /* History to fill in*/
{
unsigned char nLevl;
enum cdb_sc status;
register int n1;
register uchar_ptr_t c1, c2;
register sm_uc_ptr_t pRec, pBlkBase;
register gv_namehead *pTarg; /* Local copy of gv_target; hope it gets put into register */
register srch_blk_status *pCurr;
register srch_blk_status *pNonStar;
register srch_hist *pTargHist;
int tmp_cmpc;
block_id nBlkId;
cache_rec_ptr_t cr;
int cycle;
unsigned short n0, nKeyLen;
trans_num tn;
cw_set_element *cse;
off_chain chain1, chain2;
srch_blk_status *tp_srch_status, *srch_status, *leaf_blk_hist;
boolean_t already_built, is_mm;
ht_ent_int4 *tabent;
sm_uc_ptr_t buffaddr;
trans_num blkhdrtn, oldest_hist_tn;
int hist_size;
# ifdef DEBUG
boolean_t save_donot_commit;
# endif
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
pTarg = gv_target;
assert(NULL != pTarg);
assert(pTarg->root);
assert(pKey != &pTarg->clue);
nKeyLen = pKey->end + 1;
assert(!dollar_tlevel || ((NULL != sgm_info_ptr) && (cs_addrs->sgm_info_ptr == sgm_info_ptr)));
SET_GVCST_SEARCH_CLUE(0);
INCR_DB_CSH_COUNTER(cs_addrs, n_gvcst_srches, 1);
pTargHist = ((NULL == pHist) ? &pTarg->hist : pHist);
/* If FINAL RETRY and TP then we can safely use clues of gv_targets that have been referenced in this
* TP transaction (read_local_tn == local_tn). While that is guaranteed to be true for all updates, it
* does not hold good for READs since we allow a lot more reads to be done inside a transaction compared
* to the # of updates allowed. We allow the same global to be read multiple times inside the same transaction
* using different global buffers for each read. This means that we need to validate any clues from the first
* read before using it for the second read even if it is in the final retry. This validation is done inside
* the below IF block. As for gv_targets which are referenced for the very first time in this TP transaction,
* we have no easy way of determining if their clues are still uptodate (i.e. using the clue will guarantee us
* no restart) and since we are in the final retry, we dont want to take a risk. So dont use the clue in that case.
*
* If FINAL RETRY and Non-TP, we will be dealing with only ONE gv_target so its clue would have been reset as
* part of the penultimate restart so we dont have any of the above issue in the non-tp case. The only exception
* is if we are in gvcst_kill in which case, gvcst_search will be called twice and the clue could be non-zero
* for the second invocation. In this case, the clue is guaranteed to be uptodate since it was set just now
* as part of the first invocation. So no need to do anything about clue in final retry for Non-TP.
*/
if ((0 != pTarg->clue.end) && ((CDB_STAGNATE > t_tries) || !dollar_tlevel || (pTarg->read_local_tn == local_tn)))
{ /* Have non-zero clue. Check if it is usable for the current search key. If so validate clue then and use it. */
/* In t_end, we skipped validating the clue in case of reorg due to the assumption that reorg never uses the clue
* i.e. it nullifies the clue before calling gvcst_search. However, it doesn't reset the clue for directory tree
* and so continue using the clue if called for root search. Assert accordingly.
*/
assert(!mu_reorg_process UNIX_ONLY(|| (pTarg->gd_csa->dir_tree == pTarg)));
INCR_DB_CSH_COUNTER(cs_addrs, n_gvcst_srch_clues, 1);
status = cdb_sc_normal; /* clue is usable unless proved otherwise */
DEBUG_ONLY(save_donot_commit = TREF(donot_commit);)
if (NULL != pHist)
sm_uc_ptr_t t_qread(block_id blk, sm_int_ptr_t cycle, cache_rec_ptr_ptr_t cr_out)
/* cycle is used in t_end to detect if the buffer has been refreshed since the t_qread */
{
int4 status;
uint4 blocking_pid;
cache_rec_ptr_t cr;
bt_rec_ptr_t bt;
boolean_t clustered, hold_onto_crit, was_crit, issued_db_init_crypt_warning, sync_needed;
int dummy, lcnt, ocnt;
cw_set_element *cse;
off_chain chain1;
register sgmnt_addrs *csa;
register sgmnt_data_ptr_t csd;
enum db_ver ondsk_blkver;
int4 dummy_errno, gtmcrypt_errno;
boolean_t already_built, is_mm, reset_first_tp_srch_status, set_wc_blocked, sleep_invoked;
ht_ent_int4 *tabent;
srch_blk_status *blkhist;
trans_num dirty, blkhdrtn;
sm_uc_ptr_t buffaddr;
uint4 stuck_cnt = 0;
boolean_t lcl_blk_free;
node_local_ptr_t cnl;
gd_segment *seg;
uint4 buffs_per_flush, flush_target;
enc_info_t *encr_ptr;
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
lcl_blk_free = block_is_free;
block_is_free = FALSE; /* Reset to FALSE so that if t_qread fails below, we don't have an incorrect state of this var */
first_tp_srch_status = NULL;
reset_first_tp_srch_status = FALSE;
csa = cs_addrs;
csd = csa->hdr;
INCR_DB_CSH_COUNTER(csa, n_t_qreads, 1);
is_mm = (dba_mm == csd->acc_meth);
/* We better hold crit in the final retry (TP & non-TP). Only exception is journal recovery */
assert((t_tries < CDB_STAGNATE) || csa->now_crit || mupip_jnl_recover);
if (dollar_tlevel)
{
assert(sgm_info_ptr);
if (0 != sgm_info_ptr->cw_set_depth)
{
chain1 = *(off_chain *)&blk;
if (1 == chain1.flag)
{
assert(sgm_info_ptr->cw_set_depth);
if ((int)chain1.cw_index < sgm_info_ptr->cw_set_depth)
tp_get_cw(sgm_info_ptr->first_cw_set, (int)chain1.cw_index, &cse);
else
{
assert(FALSE == csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
} else
{
if (NULL != (tabent = lookup_hashtab_int4(sgm_info_ptr->blks_in_use, (uint4 *)&blk)))
first_tp_srch_status = tabent->value;
else
first_tp_srch_status = NULL;
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
cse = first_tp_srch_status ? first_tp_srch_status->cse : NULL;
}
assert(!cse || !cse->high_tlevel);
assert(!chain1.flag || cse);
if (cse)
{ /* transaction has modified the sought after block */
if ((gds_t_committed != cse->mode) || (n_gds_t_op < cse->old_mode))
{ /* Changes have not been committed to shared memory, i.e. still in private memory.
* Build block in private buffer if not already done and return the same.
*/
assert(gds_t_writemap != cse->mode);
if (FALSE == cse->done)
{ /* out of date, so make it current */
assert(gds_t_committed != cse->mode);
already_built = (NULL != cse->new_buff);
/* Validate the block's search history right after building a private copy.
* This is not needed in case gvcst_search is going to reuse the clue's search
* history and return (because tp_hist will do the validation of this block).
* But if gvcst_search decides to do a fresh traversal (because the clue does not
* cover the path of the current input key etc.) the block build that happened now
* will not get validated in tp_hist since it will instead be given the current
* key's search history path (a totally new path) for validation. Since a private
* copy of the block has been built, tp_tend would also skip validating this block
* so it is necessary that we validate the block right here. Since it is tricky to
* accurately differentiate between the two cases, we do the validation
* unconditionally here (besides it is only a few if checks done per block build
* so it is considered okay performance-wise).
*/
gvcst_blk_build(cse, (uchar_ptr_t)cse->new_buff, 0);
assert(NULL != cse->blk_target);
if (!already_built && !chain1.flag)
{
buffaddr = first_tp_srch_status->buffaddr;
cr = first_tp_srch_status->cr;
assert((is_mm || cr) && buffaddr);
blkhdrtn = ((blk_hdr_ptr_t)buffaddr)->tn;
if (TP_IS_CDB_SC_BLKMOD3(cr, first_tp_srch_status, blkhdrtn))
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_blkmod; /* should this be something else */
TP_TRACE_HIST_MOD(blk, gv_target, tp_blkmod_t_qread, cs_data,
first_tp_srch_status->tn, blkhdrtn,
((blk_hdr_ptr_t)buffaddr)->levl);
return (sm_uc_ptr_t)NULL;
}
if (!is_mm && ((first_tp_srch_status->cycle != cr->cycle)
|| (first_tp_srch_status->blk_num != cr->blk)))
{
assert(CDB_STAGNATE > t_tries);
rdfail_detail = cdb_sc_lostcr; /* should this be something else */
return (sm_uc_ptr_t)NULL;
}
}
cse->done = TRUE;
}
*cycle = CYCLE_PVT_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)cse->new_buff;
} else
{ /* Block changes are already committed to shared memory (possible if we are in TP
* in the 2nd phase of M-Kill in gvcst_expand_free_subtree.c). In this case, read
* block from shared memory; do not look at private memory (i.e. cse) as that might
* not be as uptodate as shared memory.
*/
assert(csa->now_crit); /* gvcst_expand_free_subtree does t_qread in crit */
/* If this block was newly created as part of the TP transaction, it should not be killed
* as part of the 2nd phase of M-kill. This is because otherwise the block's cse would
* have had an old_mode of kill_t_create in which case we would not have come into this
* else block. Assert accordingly.
*/
assert(!chain1.flag);
first_tp_srch_status = NULL; /* do not use any previous srch_hist information */
}
}
} else
{
if (NULL != (tabent = lookup_hashtab_int4(sgm_info_ptr->blks_in_use, (uint4 *)&blk)))
first_tp_srch_status = tabent->value;
else
first_tp_srch_status = NULL;
}
ASSERT_IS_WITHIN_TP_HIST_ARRAY_BOUNDS(first_tp_srch_status, sgm_info_ptr);
if (!is_mm && first_tp_srch_status)
{
cr = first_tp_srch_status->cr;
assert(cr && !first_tp_srch_status->cse);
if (first_tp_srch_status->cycle == cr->cycle)
{
*cycle = first_tp_srch_status->cycle;
*cr_out = cr;
cr->refer = TRUE;
if (CDB_STAGNATE <= t_tries) /* mu_reorg doesn't use TP else should have an || for that */
CWS_INSERT(blk);
return (sm_uc_ptr_t)first_tp_srch_status->buffaddr;
} else
{ /* Block was already part of the read-set of this transaction, but got recycled in the cache.
* Allow block recycling by resetting first_tp_srch_status for this blk to reflect the new
* buffer, cycle and cache-record. tp_hist (invoked much later) has validation checks to detect
* if block recycling happened within the same mini-action and restart in that case.
* Updating first_tp_srch_status has to wait until the end of t_qread since only then do we know
* the values to update to. Set a variable that will enable the updation before returning.
* Also assert that if we are in the final retry, we are never in a situation where we have a
* block that got recycled since the start of the current mini-action. This is easily detected since
* as part of the final retry we maintain a hash-table "cw_stagnate" that holds the blocks that
* have been read as part of the current mini-action until now.
*/
assert(CDB_STAGNATE > t_tries || (NULL == lookup_hashtab_int4(&cw_stagnate, (uint4 *)&blk)));
reset_first_tp_srch_status = TRUE;
}
}
}
if ((uint4)blk >= (uint4)csa->ti->total_blks)
{ /* Requested block out of range; could occur because of a concurrency conflict. mm_read and dsk_read assume blk is
* never negative or greater than the maximum possible file size. If a concurrent REORG truncates the file, t_qread
* can proceed despite blk being greater than total_blks. But dsk_read handles this fine; see comments below.
*/
assert((&FILE_INFO(gv_cur_region)->s_addrs == csa) && (csd == cs_data));
assert(!csa->now_crit);
rdfail_detail = cdb_sc_blknumerr;
return (sm_uc_ptr_t)NULL;
}
if (is_mm)
{
*cycle = CYCLE_SHRD_COPY;
*cr_out = 0;
return (sm_uc_ptr_t)(mm_read(blk));
}
was_crit = csa->now_crit;
cnl = csa->nl;
encr_ptr = csa->encr_ptr;
if (NULL != encr_ptr)
{
/* If this is an encrypted database and we hold crit, make sure our private cycle matches the shared cycle.
* Or else we would need to call "process_reorg_encrypt_restart" below (a heavyweight operation) holding crit.
*/
assert(!was_crit || (cnl->reorg_encrypt_cycle == encr_ptr->reorg_encrypt_cycle));
seg = gv_cur_region->dyn.addr;
issued_db_init_crypt_warning = encr_ptr->issued_db_init_crypt_warning;
if (!IS_BITMAP_BLK(blk) && issued_db_init_crypt_warning)
{ /* A non-GT.M process is attempting to read a non-bitmap block, yet it has previously encountered an error
* during db_init (because it did not have access to the encryption keys) and reported it with a -W-
* severity. Since the block it is attempting to read can be in the unencrypted shared memory (read from
* disk by another process with access to the encryption keys), we cannot let it access it without a valid
* handle, so issue an rts_error.
*
* TODO: DSE and LKE could bypass getting the ftok semaphore. LKE is not an issue, but DSE does care about
* the csa->reorg_encrypt_cycle. So it means DSE could get an inconsistent copy of reorg_encrypt_cycle
* and associated hashes if it had done a bypass and a concurrent REORG -ENCRYPT is holding the ftok
* semaphore and changing these values at the same time.
*/
assert(!IS_GTM_IMAGE); /* GT.M would have error'ed out in db_init */
gtmcrypt_errno = SET_REPEAT_MSG_MASK(SET_CRYPTERR_MASK(ERR_CRYPTBADCONFIG));
GTMCRYPT_REPORT_ERROR(gtmcrypt_errno, rts_error, seg->fname_len, seg->fname);
} else if (cnl->reorg_encrypt_cycle != encr_ptr->reorg_encrypt_cycle)
{ /* A concurrent MUPIP REORG ENCRYPT occurred. Cannot proceed with the read even if the block is
* already loaded from disk into the unencrypted global buffers (security issue). Need to load the
* new encryption keys and only let those processes which are able to successfully do this proceed
* with the read. First, copy the key hashes from csd into csa->encr_ptr. That needs crit
* to ensure a concurrent MUPIP REORG ENCRYPT does not sneak in.
*
* Note: Even though we asserted a few lines above that if "was_crit" is TRUE, then we expect
* the encryption cycles to be in sync, we handle this out-of-design situation in "pro" by fixing
* the cycles while holding crit (hopefully rare case so it is okay to hold crit for a heavyweight call).
*/
if (!was_crit)
grab_crit(gv_cur_region);
/* Now that we have crit, sync them up by copying the new keys inside crit and opening the key handles
* outside crit (a potentially long running operation).
*/
SIGNAL_REORG_ENCRYPT_RESTART(mu_reorg_encrypt_in_prog, reorg_encrypt_restart_csa,
cnl, csa, csd, rdfail_detail, process_id);
assert(csa == reorg_encrypt_restart_csa);
if (!was_crit)
rel_crit(gv_cur_region);
/* If we are inside a TP read-write transaction, it is possible we already used the old keys for
* prior calls to "jnl_format" so we have to restart (cannot sync up cycles). Do the same for
* TP read-only transaction as well as NON-TP read-write transaction. In all these cases we know
* the caller is capable of restarting. All other cases we dont know if the caller is capable so
* sync up the cycles and proceed using the new keys for the read.
*
* But since it is possible the caller does not call t_retry right away (e.g. mupip reorg which can
* choose to abandone this tree path and move on to another block without aborting this transaction)
* it is better we finish the pending call to "process_reorg_encrypt_restart" right here before returning.
*/
process_reorg_encrypt_restart();
assert(NULL == reorg_encrypt_restart_csa);
if (IS_NOT_SAFE_TO_SYNC_NEW_KEYS(dollar_tlevel, update_trans))
{
assert(cdb_sc_reorg_encrypt == rdfail_detail); /* set by SIGNAL_REORG_ENCRYPT_RESTART macro */
return (sm_uc_ptr_t)NULL;
}
}
}
assert(dba_bg == csd->acc_meth);
assert(!first_tp_srch_status || !first_tp_srch_status->cr
|| first_tp_srch_status->cycle != first_tp_srch_status->cr->cycle);
if (FALSE == (clustered = csd->clustered))
bt = NULL;
ocnt = 0;
set_wc_blocked = FALSE; /* to indicate whether cnl->wc_blocked was set to TRUE by us */
hold_onto_crit = csa->hold_onto_crit; /* note down in local to avoid csa-> dereference in multiple usages below */
do
{
if (NULL == (cr = db_csh_get(blk)))
{ /* not in memory */
if (clustered && (NULL != (bt = bt_get(blk))) && (FALSE == bt->flushing))
bt = NULL;
if (!csa->now_crit)
{
assert(!hold_onto_crit);
if (NULL != bt)
{ /* at this point, bt is not NULL only if clustered and flushing - wait no crit */
assert(clustered);
wait_for_block_flush(bt, blk); /* try for no other node currently writing the block */
}
/* assume defaults for flush_target and buffs_per_flush */
flush_target = csd->flush_trigger;
buffs_per_flush = 0;
if ((0 != csd->epoch_taper) && (FALSE == gv_cur_region->read_only) && JNL_ENABLED(csd) &&
(0 != cnl->wcs_active_lvl) && (NOJNL != csa->jnl->channel) &&
(0 != cnl->jnl_file.u.inode) && csd->jnl_before_image)
{
EPOCH_TAPER_IF_NEEDED(csa, csd, cnl, (gd_region *) 0, FALSE, buffs_per_flush, flush_target);
}
if ((flush_target <= cnl->wcs_active_lvl) && (FALSE == gv_cur_region->read_only))
JNL_ENSURE_OPEN_WCS_WTSTART(csa, gv_cur_region, buffs_per_flush, dummy_errno);
/* a macro that dclast's "wcs_wtstart" and checks for errors etc. */
/* Get crit but also ensure encryption cycles are in sync ("dsk_read" relies on this).
* Note: "sync_needed" should be TRUE very rarely since we synced the cycles just a few lines
* above. But in case a MUPIP REORG ENCRYPT concurrently sneaked in between these lines we
* need to resync.
*/
sync_needed = grab_crit_encr_cycle_sync(gv_cur_region);
assert(NULL == reorg_encrypt_restart_csa);
assert(!sync_needed || (NULL != encr_ptr));
if (sync_needed && IS_NOT_SAFE_TO_SYNC_NEW_KEYS(dollar_tlevel, update_trans))
{
assert(cnl->reorg_encrypt_cycle == encr_ptr->reorg_encrypt_cycle);
rel_crit(gv_cur_region);
rdfail_detail = cdb_sc_reorg_encrypt; /* set by SIGNAL_REORG_ENCRYPT_RESTART macro */
return (sm_uc_ptr_t)NULL;
}
cr = db_csh_get(blk); /* in case blk arrived before crit */
}
if (clustered && (NULL != (bt = bt_get(blk))) && (TRUE == bt->flushing))
{ /* Once crit, need to assure that if clustered, that flushing is [still] complete
* If it isn't, we missed an entire WM cycle and have to wait for another node to finish */
wait_for_block_flush(bt, blk); /* ensure no other node currently writing the block */
}
if (NULL == cr)
{ /* really not in memory - must get a new buffer */
assert(csa->now_crit);
cr = db_csh_getn(blk);
if (CR_NOTVALID == (sm_long_t)cr)
{
assert(cnl->wc_blocked); /* only reason we currently know wcs_get_space could fail */
assert(gtm_white_box_test_case_enabled);
SET_TRACEABLE_VAR(cnl->wc_blocked, TRUE);
BG_TRACE_PRO_ANY(csa, wc_blocked_t_qread_db_csh_getn_invalid_blk);
set_wc_blocked = TRUE;
break;
}
assert(0 <= cr->read_in_progress);
*cycle = cr->cycle;
cr->tn = csd->trans_hist.curr_tn;
/* Record history of most recent disk reads only in dbg builds for now. Although the macro
* is just a couple dozen instructions, it is done while holding crit so we want to avoid
* delaying crit unless really necessary. Whoever wants this information can enable it
* by a build change to remove the DEBUG_ONLY part below.
*/
DEBUG_ONLY(DSKREAD_TRACE(csa, GDS_ANY_ABS2REL(csa,cr), cr->tn, process_id, blk, cr->cycle);)
if (!was_crit && !hold_onto_crit)
rel_crit(gv_cur_region);
/* read outside of crit may be of a stale block but should be detected by t_end or tp_tend */
assert(0 == cr->dirty);
assert(cr->read_in_progress >= 0);
CR_BUFFER_CHECK(gv_cur_region, csa, csd, cr);
buffaddr = (sm_uc_ptr_t)GDS_REL2ABS(cr->buffaddr);
# ifdef DEBUG
/* stop self to test sechshr_db_clnup clears the read state */
if (gtm_white_box_test_case_enabled
&& (WBTEST_SIGTSTP_IN_T_QREAD == gtm_white_box_test_case_number))
{ /* this should never fail, but because of the way we developed the test we got paranoid */
dummy = kill(process_id, SIGTERM);
assert(0 == dummy);
for (dummy = 10; dummy; dummy--)
LONG_SLEEP(10); /* time for sigterm to take hit before we clear block_now_locked */
}
# endif
if (SS_NORMAL != (status = dsk_read(blk, buffaddr, &ondsk_blkver, lcl_blk_free)))
{
/* buffer does not contain valid data, so reset blk to be empty */
cr->cycle++; /* increment cycle for blk number changes (for tp_hist and others) */
cr->blk = CR_BLKEMPTY;
cr->r_epid = 0;
RELEASE_BUFF_READ_LOCK(cr);
TREF(block_now_locked) = NULL;
assert(-1 <= cr->read_in_progress);
assert(was_crit == csa->now_crit);
if (ERR_DYNUPGRDFAIL == status)
{ /* if we dont hold crit on the region, it is possible due to concurrency conflicts
* that this block is unused (i.e. marked free/recycled in bitmap, see comments in
* gds_blk_upgrade.h). in this case we should not error out but instead restart.
*/
if (was_crit)
{
assert(FALSE);
rts_error_csa(CSA_ARG(csa) VARLSTCNT(5) status, 3, blk,
DB_LEN_STR(gv_cur_region));
} else
{
rdfail_detail = cdb_sc_lostcr;
return (sm_uc_ptr_t)NULL;
}
}
if ((-1 == status) && !was_crit)
{ /* LSEEKREAD and, consequently, dsk_read return -1 in case pread is unable to fetch
* a full database block's length of data. This can happen if the requested read is
* past the end of the file, which can happen if a concurrent truncate occurred
* after the blk >= csa->ti->total_blks comparison above. Allow for this scenario
* by restarting. However, if we've had crit the whole time, no truncate could have
* happened. -1 indicates a problem with the file, so fall through to DBFILERR.
*/
rdfail_detail = cdb_sc_truncate;
return (sm_uc_ptr_t)NULL;
} else if (IS_CRYPTERR_MASK(status))
{
seg = gv_cur_region->dyn.addr;
GTMCRYPT_REPORT_ERROR(status, rts_error, seg->fname_len, seg->fname);
}
else
{ /* A DBFILERR can be thrown for two possible reasons:
* (1) LSEEKREAD returned an unexpected error due to a filesystem problem; or
* (2) csa/cs_addrs/csd/cs_data are out of sync, and we're trying to read a block
* number for one region from another region with fewer total_blks.
* We suspect the former is what happened in GTM-7623. Apparently the latter
* has been an issue before, too. If either occurs again in pro, this assertpro
* distinguishes the two possibilities.
*/
assertpro((&FILE_INFO(gv_cur_region)->s_addrs == csa) && (csd == cs_data));
rts_error_csa(CSA_ARG(csa) VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(gv_cur_region),
status);
}
}
disk_blk_read = TRUE;
assert(0 <= cr->read_in_progress);
assert(0 == cr->dirty);
/* Only set in cache if read was success */
cr->ondsk_blkver = (lcl_blk_free ? GDSVCURR : ondsk_blkver);
cr->r_epid = 0;
RELEASE_BUFF_READ_LOCK(cr);
TREF(block_now_locked) = NULL;
assert(-1 <= cr->read_in_progress);
*cr_out = cr;
assert(was_crit == csa->now_crit);
if (reset_first_tp_srch_status)
RESET_FIRST_TP_SRCH_STATUS(first_tp_srch_status, cr, *cycle);
return buffaddr;
} else if (!was_crit && (BAD_LUCK_ABOUNDS > ocnt))
{
assert(!hold_onto_crit);
assert(TRUE == csa->now_crit);
assert(cnl->in_crit == process_id);
rel_crit(gv_cur_region);
}
}