1 files changed, 59 insertions, 37 deletions

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 84f9a5dc8b..57e2f7409b 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -2421,38 +2421,48 @@ void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv&
         }
     }
 
-    LOCK(cs_main);
-    const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
-    if (!pindex) {
-        return;
-    }
-    if (!BlockRequestAllowed(pindex)) {
-        LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom.GetId());
-        return;
-    }
-    // disconnect node in case we have reached the outbound limit for serving historical blocks
-    if (m_connman.OutboundTargetReached(true) &&
-        (((m_chainman.m_best_header != nullptr) && (m_chainman.m_best_header->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.IsMsgFilteredBlk()) &&
-        !pfrom.HasPermission(NetPermissionFlags::Download) // nodes with the download permission may exceed target
-    ) {
-        LogPrint(BCLog::NET, "historical block serving limit reached, disconnect peer=%d\n", pfrom.GetId());
-        pfrom.fDisconnect = true;
-        return;
-    }
-    // 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 */) )
-       )) {
-        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)
-        pfrom.fDisconnect = true;
-        return;
-    }
-    // Pruned nodes may have deleted the block, so check whether
-    // it's available before trying to send.
-    if (!(pindex->nStatus & BLOCK_HAVE_DATA)) {
-        return;
+    const CBlockIndex* pindex{nullptr};
+    const CBlockIndex* tip{nullptr};
+    bool can_direct_fetch{false};
+    FlatFilePos block_pos{};
+    {
+        LOCK(cs_main);
+        pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
+        if (!pindex) {
+            return;
+        }
+        if (!BlockRequestAllowed(pindex)) {
+            LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom.GetId());
+            return;
+        }
+        // disconnect node in case we have reached the outbound limit for serving historical blocks
+        if (m_connman.OutboundTargetReached(true) &&
+            (((m_chainman.m_best_header != nullptr) && (m_chainman.m_best_header->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.IsMsgFilteredBlk()) &&
+            !pfrom.HasPermission(NetPermissionFlags::Download) // nodes with the download permission may exceed target
+        ) {
+            LogPrint(BCLog::NET, "historical block serving limit reached, disconnect peer=%d\n", pfrom.GetId());
+            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) && (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)
+            pfrom.fDisconnect = true;
+            return;
+        }
+        // Pruned nodes may have deleted the block, so check whether
+        // it's available before trying to send.
+        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;
@@ -2460,16 +2470,28 @@ 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)) {
+            if (WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.IsBlockPruned(*pindex))) {
+                LogPrint(BCLog::NET, "Block was pruned before it could be read, disconnect peer=%s\n", pfrom.GetId());
+            } else {
+                LogError("Cannot load block from disk, disconnect peer=%d\n", pfrom.GetId());
+            }
+            pfrom.fDisconnect = true;
+            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)) {
+            if (WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.IsBlockPruned(*pindex))) {
+                LogPrint(BCLog::NET, "Block was pruned before it could be read, disconnect peer=%s\n", pfrom.GetId());
+            } else {
+                LogError("Cannot load block from disk, disconnect peer=%d\n", pfrom.GetId());
+            }
+            pfrom.fDisconnect = true;
+            return;
         }
         pblock = pblockRead;
     }
@@ -2507,7 +2529,7 @@ 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 {
@@ -2528,7 +2550,7 @@ 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();
         }