8cad15b156
Add simple transaction API to use in further update of block graph operations. Supposed usage is: - "prepare" is main function of the action and it should make the main effect of the action to be visible for the following actions, keeping possibility of roll-back, saving necessary things in action state, which is prepended to the action list (to do that, prepare func should call tran_add()). So, driver struct doesn't include "prepare" field, as it is supposed to be called directly. - commit/rollback is supposed to be called for the list of action states, to commit/rollback all the actions in reverse order - When possible "commit" should not make visible effect for other actions, which make possible transparent logical interaction between actions. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-9-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
97 lines
2.2 KiB
C
97 lines
2.2 KiB
C
/*
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* Simple transactions API
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*
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* Copyright (c) 2021 Virtuozzo International GmbH.
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*
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* Author:
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* Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu/osdep.h"
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#include "qemu/transactions.h"
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#include "qemu/queue.h"
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typedef struct TransactionAction {
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TransactionActionDrv *drv;
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void *opaque;
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QSLIST_ENTRY(TransactionAction) entry;
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} TransactionAction;
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struct Transaction {
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QSLIST_HEAD(, TransactionAction) actions;
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};
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Transaction *tran_new(void)
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{
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Transaction *tran = g_new(Transaction, 1);
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QSLIST_INIT(&tran->actions);
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return tran;
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}
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void tran_add(Transaction *tran, TransactionActionDrv *drv, void *opaque)
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{
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TransactionAction *act;
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act = g_new(TransactionAction, 1);
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*act = (TransactionAction) {
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.drv = drv,
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.opaque = opaque
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};
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QSLIST_INSERT_HEAD(&tran->actions, act, entry);
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}
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void tran_abort(Transaction *tran)
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{
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TransactionAction *act, *next;
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QSLIST_FOREACH_SAFE(act, &tran->actions, entry, next) {
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if (act->drv->abort) {
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act->drv->abort(act->opaque);
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}
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if (act->drv->clean) {
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act->drv->clean(act->opaque);
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}
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g_free(act);
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}
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g_free(tran);
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}
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void tran_commit(Transaction *tran)
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{
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TransactionAction *act, *next;
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QSLIST_FOREACH_SAFE(act, &tran->actions, entry, next) {
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if (act->drv->commit) {
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act->drv->commit(act->opaque);
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}
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if (act->drv->clean) {
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act->drv->clean(act->opaque);
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}
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g_free(act);
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}
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g_free(tran);
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}
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