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lmdb: cleanup mdb_txn_begin().

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Change-Id: Ia28e255a0497d02f7d87ca301d5be8a60886d4e1
This commit is contained in:
Hallvard Furuseth 2015-07-04 13:48:03 +02:00 committed by Leo Yuriev
parent b3a3dc4c6b
commit 82213d732c
1 changed files with 12 additions and 22 deletions
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34
mdb.c
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@ -2881,7 +2881,6 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned 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;
@ -2891,41 +2890,31 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned 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) {
mdb_debug("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 *)(txn->mt_cursors + env->me_maxdbs);
txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
}
txn->mt_dbxs = env->me_dbxs;
}
txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;
txn->mt_flags = flags;
txn->mt_env = env;
if (parent) {
unsigned 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)))
@ -2962,7 +2951,8 @@ mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned 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);
}
@ -2970,7 +2960,7 @@ 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;
mdb_debug("begin txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',