From b0665f7016306e658235703d15b454fcef7e6d3d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=D0=9B=D0=B5=D0=BE=D0=BD=D0=B8=D0=B4=20=D0=AE=D1=80=D1=8C?= =?UTF-8?q?=D0=B5=D0=B2=20=28Leonid=20Yuriev=29?= Date: Thu, 6 Mar 2025 02:48:55 +0300 Subject: [PATCH] =?UTF-8?q?mdbx:=20=D0=B7=D0=B0=D0=BF=D1=80=D0=B5=D1=89?= =?UTF-8?q?=D0=B5=D0=BD=D0=B8=D0=B5=20unbind/close=20=D0=BA=D1=83=D1=80?= =?UTF-8?q?=D1=81=D0=BE=D1=80=D0=BE=D0=B2=20=D0=B4=D0=BB=D1=8F=20=D0=B2?= =?UTF-8?q?=D0=BB=D0=BE=D0=B6=D0=B5=D0=BD=D0=BD=D1=8B=D1=85=20=D1=82=D1=80?= =?UTF-8?q?=D0=B0=D0=BD=D0=B7=D0=B0=D0=BA=D1=86=D0=B8=D0=B9.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- mdbx.h | 20 ++++++++++-- src/api-cursor.c | 79 +++++++++++++++++++++--------------------------- 2 files changed, 53 insertions(+), 46 deletions(-) diff --git a/mdbx.h b/mdbx.h index dbf622a8..e971ade5 100644 --- a/mdbx.h +++ b/mdbx.h @@ -5124,6 +5124,10 @@ MDBX_NOTHROW_PURE_FUNCTION LIBMDBX_API void *mdbx_cursor_get_userctx(const MDBX_ * the same table handle as it was created with. This may be done whether the * previous transaction is live or dead. * + * If the transaction is nested, then the cursor should not be used in its parent transaction. + * Otherwise it is no way to restore state if this nested transaction will be aborted, + * nor impossible to define the expected behavior. + * * \note In contrast to LMDB, the MDBX required that any opened cursors can be * reused and must be freed explicitly, regardless ones was opened in a * read-only or write transaction. The REASON for this is eliminates ambiguity @@ -5148,6 +5152,10 @@ LIBMDBX_API int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *cursor, MDBX_dbi db * the original DBI-handle internally. Thus it could be renewed with any running * transaction or closed. * + * If the transaction is nested, then the cursor should not be used in its parent transaction. + * Otherwise it is no way to restore state if this nested transaction will be aborted, + * nor impossible to define the expected behavior. + * * \see mdbx_cursor_renew() * \see mdbx_cursor_bind() * \see mdbx_cursor_close() @@ -5232,6 +5240,10 @@ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor); * Unbinds either closes all cursors associated (opened or renewed) with * a given transaction in a bulk with minimal overhead. * + * A transaction should not be nested, since in this case no way to restore + * state if this nested transaction will be aborted, nor impossible to define + * the expected behavior. + * * \see mdbx_cursor_unbind() * \see mdbx_cursor_close() * @@ -5245,7 +5257,7 @@ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor); * some possible errors are: * \retval MDBX_THREAD_MISMATCH Given transaction is not owned * by current thread. - * \retval MDBX_BAD_TXN Given transaction is invalid or has + * \retval MDBX_BAD_TXN Given transaction is invalid, nested or has * a child/nested transaction transaction. */ LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind, size_t *count); @@ -5255,6 +5267,10 @@ LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind * Unbinds either closes all cursors associated (opened or renewed) with * a given transaction in a bulk with minimal overhead. * + * A transaction should not be nested, since in this case no way to restore + * state if this nested transaction will be aborted, nor impossible to define + * the expected behavior. + * * \see mdbx_cursor_unbind() * \see mdbx_cursor_close() * @@ -5266,7 +5282,7 @@ LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind * some possible errors are: * \retval MDBX_THREAD_MISMATCH Given transaction is not owned * by current thread. - * \retval MDBX_BAD_TXN Given transaction is invalid or has + * \retval MDBX_BAD_TXN Given transaction is invalid, nested or has * a child/nested transaction transaction. */ LIBMDBX_INLINE_API(int, mdbx_txn_release_all_cursors, (const MDBX_txn *txn, bool unbind)) { return mdbx_txn_release_all_cursors_ex(txn, unbind, NULL); diff --git a/src/api-cursor.c b/src/api-cursor.c index 4a4b34c8..05c98b4b 100644 --- a/src/api-cursor.c +++ b/src/api-cursor.c @@ -44,8 +44,10 @@ int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *mc, MDBX_dbi dbi) { if (unlikely(!mc)) return LOG_IFERR(MDBX_EINVAL); - if (unlikely(mc->signature != cur_signature_ready4dispose && mc->signature != cur_signature_live)) - return LOG_IFERR(MDBX_EBADSIGN); + if (unlikely(mc->signature != cur_signature_ready4dispose && mc->signature != cur_signature_live)) { + int rc = (mc->signature == cur_signature_wait4eot) ? MDBX_EINVAL : MDBX_EBADSIGN; + return LOG_IFERR(rc); + } int rc = check_txn(txn, MDBX_TXN_BLOCKED); if (unlikely(rc != MDBX_SUCCESS)) @@ -58,24 +60,12 @@ int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *mc, MDBX_dbi dbi) { if (unlikely(dbi == FREE_DBI && !(txn->flags & MDBX_TXN_RDONLY))) return LOG_IFERR(MDBX_EACCESS); - if (unlikely(mc->backup)) /* Cursor from parent transaction */ { - cASSERT(mc, mc->signature == cur_signature_live); - if (unlikely(cursor_dbi(mc) != dbi || - /* paranoia */ mc->signature != cur_signature_live || mc->txn != txn)) - return LOG_IFERR(MDBX_EINVAL); - - cASSERT(mc, mc->tree == &txn->dbs[dbi]); - cASSERT(mc, mc->clc == &txn->env->kvs[dbi].clc); - cASSERT(mc, cursor_dbi(mc) == dbi); - return likely(cursor_dbi(mc) == dbi && - /* paranoia */ mc->signature == cur_signature_live && mc->txn == txn) - ? MDBX_SUCCESS - : LOG_IFERR(MDBX_EINVAL) /* Disallow change DBI in nested - transactions */ - ; - } + if (unlikely(mc->backup)) /* Cursor from parent transaction */ + LOG_IFERR(MDBX_EINVAL); if (mc->signature == cur_signature_live) { + if (mc->txn == txn && cursor_dbi(mc) == dbi) + return MDBX_SUCCESS; rc = mdbx_cursor_unbind(mc); if (unlikely(rc != MDBX_SUCCESS)) return rc; @@ -100,25 +90,22 @@ int mdbx_cursor_unbind(MDBX_cursor *mc) { return (mc->signature == cur_signature_ready4dispose) ? MDBX_SUCCESS : LOG_IFERR(MDBX_EBADSIGN); if (unlikely(mc->backup)) /* Cursor from parent transaction */ + /* TODO: реализовать при переходе на двусвязный список курсоров */ return LOG_IFERR(MDBX_EINVAL); - eASSERT(nullptr, mc->txn && mc->txn->signature == txn_signature); - cASSERT(mc, mc->signature == cur_signature_live); - cASSERT(mc, !mc->backup); if (unlikely(!mc->txn || mc->txn->signature != txn_signature)) { ERROR("Wrong cursor's transaction %p 0x%x", __Wpedantic_format_voidptr(mc->txn), mc->txn ? mc->txn->signature : 0); return LOG_IFERR(MDBX_PROBLEM); } + if (mc->next != mc) { - const size_t dbi = (kvx_t *)mc->clc - mc->txn->env->kvs; - cASSERT(mc, cursor_dbi(mc) == dbi); + const size_t dbi = cursor_dbi(mc); cASSERT(mc, dbi < mc->txn->n_dbi); + cASSERT(mc, &mc->txn->env->kvs[dbi].clc == mc->clc); if (dbi < mc->txn->n_dbi) { MDBX_cursor **prev = &mc->txn->cursors[dbi]; - while (*prev) { + while (/* *prev && */ *prev != mc) { ENSURE(mc->txn->env, (*prev)->signature == cur_signature_live || (*prev)->signature == cur_signature_wait4eot); - if (*prev == mc) - break; prev = &(*prev)->next; } cASSERT(mc, *prev == mc); @@ -219,30 +206,34 @@ again: int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind, size_t *count) { int rc = check_txn(txn, MDBX_TXN_FINISHED | MDBX_TXN_HAS_CHILD); + if (unlikely(rc != MDBX_SUCCESS)) + return LOG_IFERR(rc); + if (unlikely(txn->parent)) { + rc = MDBX_BAD_TXN; + ERROR("%s, err %d", "must not unbind or close cursors for a nested txn", rc); + return rc; + } + size_t n = 0; - if (likely(rc == MDBX_SUCCESS)) { - TXN_FOREACH_DBI_FROM(txn, i, MAIN_DBI) { - while (txn->cursors[i]) { - ++n; - MDBX_cursor *mc = txn->cursors[i]; - ENSURE(nullptr, mc->signature == cur_signature_live && (mc->next != mc) && !mc->backup); - txn->cursors[i] = mc->next; - mc->next = mc; - if (unbind) { - be_poor(mc); - mc->signature = cur_signature_ready4dispose; - } else { - mc->signature = 0; - osal_free(mc); - } + TXN_FOREACH_DBI_FROM(txn, i, MAIN_DBI) { + while (txn->cursors[i]) { + ++n; + MDBX_cursor *mc = txn->cursors[i]; + ENSURE(nullptr, mc->signature == cur_signature_live && (mc->next != mc) && !mc->backup); + txn->cursors[i] = mc->next; + mc->next = mc; + if (unbind) { + be_poor(mc); + mc->signature = cur_signature_ready4dispose; + } else { + mc->signature = 0; + osal_free(mc); } } - } else { - LOG_IFERR(rc); } if (count) *count = n; - return rc; + return MDBX_SUCCESS; } int mdbx_cursor_compare(const MDBX_cursor *l, const MDBX_cursor *r, bool ignore_multival) {