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Alter assumptions in CCoinsViewCache::BatchWrite

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Previously it would break if you flushed a parent cache while there was a child cache referring to it.  This change will allow the flushing of parent caches.
This commit is contained in:
Alex Morcos 2015-03-26 13:52:10 -04:00
parent 73fa5e6043
commit 072e2f8644
2 changed files with 28 additions and 7 deletions
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19
src/coins.cpp
View file

@ -160,18 +160,23 @@ bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn
if (it->second.flags & CCoinsCacheEntry::DIRTY) { // Ignore non-dirty entries (optimization). if (it->second.flags & CCoinsCacheEntry::DIRTY) { // Ignore non-dirty entries (optimization).
CCoinsMap::iterator itUs = cacheCoins.find(it->first); CCoinsMap::iterator itUs = cacheCoins.find(it->first);
if (itUs == cacheCoins.end()) { if (itUs == cacheCoins.end()) {
if (!it->second.coins.IsPruned()) { // The parent cache does not have an entry, while the child does
// The parent cache does not have an entry, while the child // We can ignore it if it's both FRESH and pruned in the child
// cache does have (a non-pruned) one. Move the data up, and if (!(it->second.flags & CCoinsCacheEntry::FRESH && it->second.coins.IsPruned())) {
// mark it as fresh (if the grandparent did have it, we // Otherwise we will need to create it in the parent
// would have pulled it in at first GetCoins). // and move the data up and mark it as dirty
assert(it->second.flags & CCoinsCacheEntry::FRESH);
CCoinsCacheEntry& entry = cacheCoins[it->first]; CCoinsCacheEntry& entry = cacheCoins[it->first];
entry.coins.swap(it->second.coins); entry.coins.swap(it->second.coins);
cachedCoinsUsage += entry.coins.DynamicMemoryUsage(); cachedCoinsUsage += entry.coins.DynamicMemoryUsage();
entry.flags = CCoinsCacheEntry::DIRTY | CCoinsCacheEntry::FRESH; entry.flags = CCoinsCacheEntry::DIRTY;
// We can mark it FRESH in the parent if it was FRESH in the child
// Otherwise it might have just been flushed from the parent's cache
// and already exist in the grandparent
if (it->second.flags & CCoinsCacheEntry::FRESH)
entry.flags |= CCoinsCacheEntry::FRESH;
} }
} else { } else {
// Found the entry in the parent cache
if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coins.IsPruned()) { if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coins.IsPruned()) {
// The grandparent does not have an entry, and the child is // The grandparent does not have an entry, and the child is
// modified and being pruned. This means we can just delete // modified and being pruned. This means we can just delete

16
src/test/coins_tests.cpp
View file

@ -164,14 +164,23 @@ BOOST_AUTO_TEST_CASE(coins_cache_simulation_test)
} }
} }
if (insecure_rand() % 100 == 0) {
// Every 100 iterations, flush an intermediate cache
if (stack.size() > 1 && insecure_rand() % 2 == 0) {
unsigned int flushIndex = insecure_rand() % (stack.size() - 1);
stack[flushIndex]->Flush();
}
}
if (insecure_rand() % 100 == 0) { if (insecure_rand() % 100 == 0) {
// Every 100 iterations, change the cache stack. // Every 100 iterations, change the cache stack.
if (stack.size() > 0 && insecure_rand() % 2 == 0) { if (stack.size() > 0 && insecure_rand() % 2 == 0) {
//Remove the top cache
stack.back()->Flush(); stack.back()->Flush();
delete stack.back(); delete stack.back();
stack.pop_back(); stack.pop_back();
} }
if (stack.size() == 0 || (stack.size() < 4 && insecure_rand() % 2)) { if (stack.size() == 0 || (stack.size() < 4 && insecure_rand() % 2)) {
//Add a new cache
CCoinsView* tip = &base; CCoinsView* tip = &base;
if (stack.size() > 0) { if (stack.size() > 0) {
tip = stack.back(); tip = stack.back();
@ -304,6 +313,13 @@ BOOST_AUTO_TEST_CASE(updatecoins_simulation_test)
} }
} }
if (insecure_rand() % 100 == 0) {
// Every 100 iterations, flush an intermediate cache
if (stack.size() > 1 && insecure_rand() % 2 == 0) {
unsigned int flushIndex = insecure_rand() % (stack.size() - 1);
stack[flushIndex]->Flush();
}
}
if (insecure_rand() % 100 == 0) { if (insecure_rand() % 100 == 0) {
// Every 100 iterations, change the cache stack. // Every 100 iterations, change the cache stack.
if (stack.size() > 0 && insecure_rand() % 2 == 0) { if (stack.size() > 0 && insecure_rand() % 2 == 0) {