github
/
bitcoin
mirror of https://github.com/bitcoin/bitcoin
1
Fork 0
Code Releases Activity

net: reduce LOCK(cs_main) scope in ProcessGetBlockData 

If a block is pruned before we lock cs_main, this function returns early. This behavior is not changed in this commit.
If a block is not pruned before we lock cs_main, previously we are guaranteed to send the block to the peer.
This commit changes this to have a short window after unlocking cs_main but before opening the fd that if the block is pruned and unlinked from another thread, then this function also returns early.
This commit is contained in:
Andrew Toth 2024-01-23 10:17:15 -05:00
parent dbabb97c81
commit f9d41527d5
No known key found for this signature in database
GPG Key ID: 60007AFC8938B018
1 changed files with 20 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
src/net_processing.cpp
View File

@ -2260,8 +2260,13 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
}
}
const CBlockIndex* pindex{nullptr};
const CBlockIndex* tip{nullptr};
bool can_direct_fetch{false};
FlatFilePos block_pos{};
{
LOCK(cs_main);
const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
if (!pindex) {
return;
}
@ -2278,9 +2283,10 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
pfrom.fDisconnect = true;
return;
}
tip = m_chainman.ActiveChain().Tip();
// Avoid leaking prune-height by never sending blocks below the NODE_NETWORK_LIMITED threshold
if (!pfrom.HasPermission(NetPermissionFlags::NoBan) && (
(((peer.m_our_services & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((peer.m_our_services & NODE_NETWORK) != NODE_NETWORK) && (m_chainman.ActiveChain().Tip()->nHeight - pindex->nHeight > (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2 /* add two blocks buffer extension for possible races */) )
(((peer.m_our_services & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((peer.m_our_services & NODE_NETWORK) != NODE_NETWORK) && (tip->nHeight - pindex->nHeight > (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2 /* add two blocks buffer extension for possible races */) )
)) {
LogPrint(BCLog::NET, "Ignore block request below NODE_NETWORK_LIMITED threshold, disconnect peer=%d\n", pfrom.GetId());
//disconnect node and prevent it from stalling (would otherwise wait for the missing block)
@ -2292,6 +2298,10 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
if (!(pindex->nStatus & BLOCK_HAVE_DATA)) {
return;
}
can_direct_fetch = CanDirectFetch();
block_pos = pindex->GetBlockPos();
}
std::shared_ptr<const CBlock> pblock;
if (a_recent_block && a_recent_block->GetHash() == pindex->GetBlockHash()) {
pblock = a_recent_block;
@ -2299,16 +2309,18 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
// Fast-path: in this case it is possible to serve the block directly from disk,
// as the network format matches the format on disk
std::vector<uint8_t> block_data;
if (!m_chainman.m_blockman.ReadRawBlockFromDisk(block_data, pindex->GetBlockPos())) {
assert(!"cannot load block from disk");
if (!m_chainman.m_blockman.ReadRawBlockFromDisk(block_data, block_pos)) {
LogPrint(BCLog::NET, "Cannot load block from disk. It was likely pruned before we could read it.\n");
return;
}
MakeAndPushMessage(pfrom, NetMsgType::BLOCK, Span{block_data});
// Don't set pblock as we've sent the block
} else {
// Send block from disk
std::shared_ptr<CBlock> pblockRead = std::make_shared<CBlock>();
if (!m_chainman.m_blockman.ReadBlockFromDisk(*pblockRead, *pindex)) {
assert(!"cannot load block from disk");
if (!m_chainman.m_blockman.ReadBlockFromDisk(*pblockRead, block_pos)) {
LogPrint(BCLog::NET, "Cannot load block from disk. It was likely pruned before we could read it.\n");
return;
}
pblock = pblockRead;
}
@ -2346,7 +2358,7 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
// they won't have a useful mempool to match against a compact block,
// and we don't feel like constructing the object for them, so
// instead we respond with the full, non-compact block.
if (CanDirectFetch() && pindex->nHeight >= m_chainman.ActiveChain().Height() - MAX_CMPCTBLOCK_DEPTH) {
if (can_direct_fetch && pindex->nHeight >= tip->nHeight - MAX_CMPCTBLOCK_DEPTH) {
if (a_recent_compact_block && a_recent_compact_block->header.GetHash() == pindex->GetBlockHash()) {
MakeAndPushMessage(pfrom, NetMsgType::CMPCTBLOCK, *a_recent_compact_block);
} else {
@ -2367,7 +2379,7 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
// and we want it right after the last block so they don't
// wait for other stuff first.
std::vector<CInv> vInv;
vInv.emplace_back(MSG_BLOCK, m_chainman.ActiveChain().Tip()->GetBlockHash());
vInv.emplace_back(MSG_BLOCK, tip->GetBlockHash());
MakeAndPushMessage(pfrom, NetMsgType::INV, vInv);
peer.m_continuation_block.SetNull();
}