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https://github.com/isar/libmdbx.git
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mdbx: rework support for ThreadSanitizer.
Change-Id: I6a1cc980fa835215d2051f68bbf8580b747e6d6b
This commit is contained in:
Leo Yuriev
parent
c809b2e12c
commit
9d775b0a36
84
mdb.c
84
mdb.c
@ -1883,7 +1883,7 @@ static MDB_meta* mdb_meta_head_w(MDB_env *env) {
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return a;
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}
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static ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by meta->mm_txnid */
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static
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MDB_meta* mdb_meta_head_r(MDB_env *env) {
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MDB_meta* a = METAPAGE_1(env);
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MDB_meta* b = METAPAGE_2(env), *h;
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@ -1893,15 +1893,26 @@ MDB_meta* mdb_meta_head_r(MDB_env *env) {
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while(1) {
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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head_txnid = env->me_txns->mti_txnid;
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mdb_assert(env, a->mm_txnid != b->mm_txnid || head_txnid == 0);
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if (likely(a->mm_txnid == head_txnid))
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if (likely(a->mm_txnid == head_txnid)) {
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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return a;
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if (likely(b->mm_txnid == head_txnid))
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}
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if (likely(b->mm_txnid == head_txnid)) {
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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return b;
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}
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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/* LY: got a race on env->me_txns->mti_txnid with mdb_env_sync0() */
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#if defined(__i386__) || defined(__x86_64__)
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@ -1933,9 +1944,12 @@ static int mdb_meta_lt(MDB_meta* a, MDB_meta* b) {
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}
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/** Find oldest txnid still referenced. */
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static ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by reader[].mr_txnid */
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static
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txnid_t mdb_find_oldest(MDB_env *env, int *laggard)
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{
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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int i, reader;
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MDB_reader *r = env->me_txns->mti_readers;
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txnid_t oldest = env->me_txns->mti_txnid;
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@ -1956,6 +1970,9 @@ txnid_t mdb_find_oldest(MDB_env *env, int *laggard)
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}
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}
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}
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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if (laggard)
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*laggard = reader;
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@ -2729,22 +2746,25 @@ mdb_reader_pid(MDB_env *env, int op, pid_t pid)
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}
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}
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static ATTRIBUTE_NO_SANITIZE_THREAD
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txnid_t lead_txnid__tsan_workaround(MDB_txn *txn, MDB_reader *r)
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static
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txnid_t lead_txnid(MDB_txn *txn, MDB_reader *r)
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{
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while(1) { /* LY: Retry on a race, ITS#7970. */
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MDB_meta *meta = mdb_meta_head_r(txn->mt_env);
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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txnid_t lead = meta->mm_txnid;
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r->mr_txnid = lead;
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mdb_coherent_barrier();
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/* Copy the DB info and flags */
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memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));
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txn->mt_next_pgno = meta->mm_last_pg+1;
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if (likely(lead == txn->mt_env->me_txns->mti_txnid)) {
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txnid_t snap = txn->mt_env->me_txns->mti_txnid;
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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pthread_mutex_unlock(&tsan_mutex);
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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if (likely(lead == snap)) {
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return lead;
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}
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#if defined(__i386__) || defined(__x86_64__)
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@ -2839,11 +2859,18 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
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r->mr_txnid = ~(txnid_t)0;
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r->mr_tid = tid;
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mdb_coherent_barrier();
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if (i == nr)
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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if (i == nr) {
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env->me_txns->mti_numreaders = ++nr;
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}
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if (env->me_close_readers < nr)
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env->me_close_readers = nr;
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r->mr_pid = pid;
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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mdb_mutex_unlock(env, rmutex);
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new_notls = MDB_END_SLOT;
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@ -2854,7 +2881,7 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
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}
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}
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txn->mt_txnid = lead_txnid__tsan_workaround(txn, r);
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txn->mt_txnid = lead_txnid(txn, r);
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txn->mt_u.reader = r;
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txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
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} else {
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@ -2865,11 +2892,13 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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MDB_meta *meta = mdb_meta_head_w(env);
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txn->mt_txnid = meta->mm_txnid + 1;
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txn->mt_flags = flags;
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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#if MDB_DEBUG
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if (unlikely(txn->mt_txnid == mdb_debug_edge)) {
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@ -3159,6 +3188,9 @@ mdb_txn_end(MDB_txn *txn, unsigned mode)
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if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
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if (txn->mt_u.reader) {
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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txn->mt_u.reader->mr_txnid = ~(txnid_t)0;
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if (!(env->me_flags & MDB_NOTLS)) {
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txn->mt_u.reader = NULL; /* txn does not own reader */
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@ -3166,6 +3198,9 @@ mdb_txn_end(MDB_txn *txn, unsigned mode)
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txn->mt_u.reader->mr_pid = 0;
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txn->mt_u.reader = NULL;
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} /* else txn owns the slot until it does MDB_END_SLOT */
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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}
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mdb_coherent_barrier();
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txn->mt_numdbs = 0; /* prevent further DBI activity */
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@ -4188,6 +4223,9 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
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mdb_debug("writing meta page %d for root page %zu",
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offset >= env->me_psize, pending->mm_dbs[MAIN_DBI].md_root);
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if (env->me_flags & MDB_WRITEMAP) {
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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tail->mm_datasync_sign = MDB_DATASIGN_WEAK;
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tail->mm_txnid = 0;
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mdb_coherent_barrier();
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@ -4221,8 +4259,21 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
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goto fail;
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}
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mdb_invalidate_cache(env->me_map + offset, sizeof(MDB_meta));
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_lock(&tsan_mutex);
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#endif
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}
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/* Memory ordering issues are irrelevant; since the entire writer
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* is wrapped by wmutex, all of these changes will become visible
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* after the wmutex is unlocked. Since the DB is multi-version,
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* readers will get consistent data regardless of how fresh or
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* how stale their view of these values is.
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*/
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env->me_txns->mti_txnid = pending->mm_txnid;
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#ifdef __SANITIZE_THREAD__
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pthread_mutex_unlock(&tsan_mutex);
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#endif
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/* LY: step#3 - sync meta-pages. */
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if ((flags & (MDB_NOSYNC | MDB_NOMETASYNC)) == 0) {
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@ -4256,13 +4307,6 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
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}
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}
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/* Memory ordering issues are irrelevant; since the entire writer
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* is wrapped by wmutex, all of these changes will become visible
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* after the wmutex is unlocked. Since the DB is multi-version,
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* readers will get consistent data regardless of how fresh or
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* how stale their view of these values is.
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*/
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env->me_txns->mti_txnid = pending->mm_txnid;
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return MDB_SUCCESS;
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fail:
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