From ee06adb31183c726b7eba3ce1c6468b605418c36 Mon Sep 17 00:00:00 2001
From: Hallvard Furuseth <hallvard@openldap.org>
Date: Sat, 4 Jul 2015 13:48:03 +0200
Subject: [PATCH] mdb_txn_begin() cleanup
---
libraries/liblmdb/mdb.c | 33 ++++++++++++---------------------
1 file changed, 12 insertions(+), 21 deletions(-)
diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index d08e3a7c10..73490db591 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -2717,7 +2717,6 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
if (env->me_flags & MDB_RDONLY & ~flags) /* write txn in RDONLY env */
return EACCES;
- size = tsize = sizeof(MDB_txn);
if (parent) {
/* Nested transactions: Max 1 child, write txns only, no writemap */
flags |= parent->mt_flags;
@@ -2727,40 +2726,31 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
}
/* Child txns save MDB_pgstate and use own copy of cursors */
- size = tsize = sizeof(MDB_ntxn);
- size += env->me_maxdbs * sizeof(MDB_cursor *);
- } else if (!(flags & MDB_RDONLY)) {
+ size = env->me_maxdbs * (sizeof(MDB_db)+sizeof(MDB_cursor *)+1);
+ size += tsize = sizeof(MDB_ntxn);
+ } else if (flags & MDB_RDONLY) {
+ size = env->me_maxdbs * (sizeof(MDB_db)+1);
+ size += tsize = sizeof(MDB_txn);
+ } else {
/* Reuse preallocated write txn. However, do not touch it until
* mdb_txn_renew0() succeeds, since it currently may be active.
*/
txn = env->me_txn0;
goto renew;
}
- size += env->me_maxdbs * (sizeof(MDB_db)+1);
-
if ((txn = calloc(1, size)) == NULL) {
DPRINTF(("calloc: %s", strerror(errno)));
return ENOMEM;
}
txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
- if (flags & MDB_RDONLY) {
- txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
- txn->mt_dbiseqs = env->me_dbiseqs;
- } else {
- txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
- if (parent) {
- txn->mt_dbiseqs = parent->mt_dbiseqs;
- txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
- } else {
- txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
- txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
- }
- }
+ txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;
txn->mt_flags = flags;
txn->mt_env = env;
if (parent) {
unsigned int i;
+ txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
+ txn->mt_dbiseqs = parent->mt_dbiseqs;
txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
if (!txn->mt_u.dirty_list ||
!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
@@ -2797,7 +2787,8 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
rc = mdb_cursor_shadow(parent, txn);
if (rc)
mdb_txn_reset0(txn, "beginchild-fail");
- } else {
+ } else { /* MDB_RDONLY */
+ txn->mt_dbiseqs = env->me_dbiseqs;
renew:
rc = mdb_txn_renew0(txn);
}
@@ -2805,7 +2796,7 @@ renew:
if (txn != env->me_txn0)
free(txn);
} else {
- txn->mt_flags |= flags; /* for txn==me_txn0, no effect otherwise */
+ txn->mt_flags |= flags; /* could not change txn=me_txn0 earlier */
*ret = txn;
DPRINTF(("begin txn %"Z"u%c %p on mdbenv %p, root page %"Z"u",
txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',
--
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