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mdbx: check read/write txn overlapping for the same thread (MDBX_TXN_OVERLAPPING).

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Change-Id: If3488df96bd1903d5e4ca0a1fea504075dbd4a20
This commit is contained in:
Leonid Yuriev 2020-02-01 23:39:39 +03:00
parent db27654330
commit 17fe5f106b
2 changed files with 22 additions and 3 deletions
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3
mdbx.h
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@ -1479,6 +1479,9 @@ typedef enum MDBX_cursor_op {
* e.g. a transaction that started by another thread. */
#define MDBX_THREAD_MISMATCH (-30416)
/* Overlapping read and write transactions for the same thread */
#define MDBX_TXN_OVERLAPPING (-30415)
/**** FUNCTIONS & RELATED STRUCTURES ******************************************/
/* Return a string describing a given error code.

22
src/elements/core.c
View File

@ -3229,6 +3229,9 @@ static const char *__mdbx_strerr(int errnum) {
case MDBX_THREAD_MISMATCH:
return "MDBX_THREAD_MISMATCH: A thread has attempted to use a not "
"owned object, e.g. a transaction that started by another thread";
case MDBX_TXN_OVERLAPPING:
return "MDBX_TXN_OVERLAPPING: Overlapping read and write transactions for "
"the same thread";
default:
return NULL;
}
@ -5957,6 +5960,21 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
/* paranoia is appropriate here */ *env->me_oldest);
txn->mt_numdbs = env->me_numdbs;
} else {
if (unlikely(txn->mt_owner == tid))
return MDBX_BUSY;
MDBX_lockinfo *const lck = env->me_lck;
if (lck && (env->me_flags & MDBX_NOTLS) == 0) {
const unsigned snap_nreaders = lck->mti_numreaders;
for (unsigned i = 0; i < snap_nreaders; ++i) {
if (lck->mti_readers[i].mr_pid == env->me_pid &&
unlikely(lck->mti_readers[i].mr_tid == tid)) {
const txnid_t txnid = safe64_read(&lck->mti_readers[i].mr_txnid);
if (txnid >= MIN_TXNID && txnid < SAFE64_INVALID_THRESHOLD)
return MDBX_TXN_OVERLAPPING;
}
}
}
/* Not yet touching txn == env->me_txn0, it may be active */
mdbx_jitter4testing(false);
rc = mdbx_txn_lock(env, F_ISSET(flags, MDBX_TRYTXN));
@ -6187,15 +6205,13 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
size += tsize = sizeof(MDBX_txn);
} else if (flags & MDBX_RDONLY) {
if (env->me_txn0 && unlikely(env->me_txn0->mt_owner == mdbx_thread_self()))
return MDBX_BUSY;
return MDBX_TXN_OVERLAPPING;
size = env->me_maxdbs * (sizeof(MDBX_db) + 1);
size += tsize = sizeof(MDBX_txn);
} else {
/* Reuse preallocated write txn. However, do not touch it until
* mdbx_txn_renew0() succeeds, since it currently may be active. */
txn = env->me_txn0;
if (unlikely(txn->mt_owner == mdbx_thread_self()))
return MDBX_BUSY;
goto renew;
}
if (unlikely((txn = mdbx_malloc(size)) == NULL)) {