Function zil_get_commit_list

freebsd/contrib/openzfs/module/zfs/zil.c:2056–2097

* This function will traverse the queue of itxs that need to be * committed, and move them onto the ZIL's zl_itx_commit_list. */

 * committed, and move them onto the ZIL's zl_itx_commit_list.
 */
static void
zil_get_commit_list(zilog_t *zilog)
{
	uint64_t otxg, txg;
	list_t *commit_list = &zilog->zl_itx_commit_list;

	ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));

	if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
		otxg = ZILTEST_TXG;
	else
		otxg = spa_last_synced_txg(zilog->zl_spa) + 1;

	/*
	 * This is inherently racy, since there is nothing to prevent
	 * the last synced txg from changing. That's okay since we'll
	 * only commit things in the future.
	 */
	for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
		itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];

		mutex_enter(&itxg->itxg_lock);
		if (itxg->itxg_txg != txg) {
			mutex_exit(&itxg->itxg_lock);
			continue;
		}

		/*
		 * If we're adding itx records to the zl_itx_commit_list,
		 * then the zil better be dirty in this "txg". We can assert
		 * that here since we're holding the itxg_lock which will
		 * prevent spa_sync from cleaning it. Once we add the itxs
		 * to the zl_itx_commit_list we must commit it to disk even
		 * if it's unnecessary (i.e. the txg was synced).
		 */
		ASSERT(zilog_is_dirty_in_txg(zilog, txg) ||
		    spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
		list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);

		mutex_exit(&itxg->itxg_lock);
	}
}

/*
 * Move the async itxs for a specified object to commit into sync lists.