Merge b2136da98d into 66aa6a47bd

src/validation.cpp

@@ -2091,7 +2091,6 @@ void Chainstate::InvalidBlockFound(CBlockIndex* pindex, const BlockValidationSta
     AssertLockHeld(cs_main);
     if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
         pindex->nStatus |= BLOCK_FAILED_VALID;
-        m_chainman.m_failed_blocks.insert(pindex);
         m_blockman.m_dirty_blockindex.insert(pindex);
         setBlockIndexCandidates.erase(pindex);
         InvalidChainFound(pindex);
@@ -3691,6 +3690,11 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
     // build a map once so that we can look up candidate blocks by chain
     // work as we go.
     std::multimap<const arith_uint256, CBlockIndex *> candidate_blocks_by_work;
+    // Map to cache candidates not in the main chain that might need invalidating.
+    // Maps fork block in chain to the candidates for invalidation.
+    std::multimap<const CBlockIndex*, CBlockIndex*> cand_invalid_descendants;
+    // Map to cache candidates for m_best_header
+    std::multimap<const arith_uint256, CBlockIndex*> best_header_blocks_by_work;
 
     {
         LOCK(cs_main);
@@ -3707,6 +3711,12 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
                     candidate->HaveNumChainTxs()) {
                 candidate_blocks_by_work.insert(std::make_pair(candidate->nChainWork, candidate));
             }
+            // Similarly, populate cache for blocks not in main chain to invalidate
+            if (!m_chain.Contains(candidate) &&
+                !CBlockIndexWorkComparator()(candidate, pindex->pprev)) {
+                cand_invalid_descendants.insert(std::make_pair(m_chain.FindFork(candidate), candidate));
+                best_header_blocks_by_work.insert(std::make_pair(candidate->nChainWork, candidate));
+            }
         }
     }
 
@@ -3754,6 +3764,28 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
             m_blockman.m_dirty_blockindex.insert(to_mark_failed);
         }
 
+        // Mark descendants of the invalidated block as invalid
+        auto range = cand_invalid_descendants.equal_range(invalid_walk_tip);
+        for (auto it = range.first; it != range.second; ++it) {
+            it->second->nStatus |= BLOCK_FAILED_CHILD;
+        }
+
+        // Determine new best header
+        if (m_chainman.m_best_header->nStatus & BLOCK_FAILED_MASK) {
+            m_chainman.m_best_header = invalid_walk_tip->pprev;
+            auto best_header_it = best_header_blocks_by_work.lower_bound(m_chainman.m_best_header->nChainWork);
+            while (best_header_it != best_header_blocks_by_work.end()) {
+                if (best_header_it->second->nStatus & BLOCK_FAILED_MASK) {
+                    best_header_it = best_header_blocks_by_work.erase(best_header_it);
+                } else {
+                    if (!CBlockIndexWorkComparator()(best_header_it->second, m_chainman.m_best_header)) {
+                        m_chainman.m_best_header = best_header_it->second;
+                    }
+                    ++best_header_it;
+                }
+            }
+        }
+
         // Add any equal or more work headers to setBlockIndexCandidates
         auto candidate_it = candidate_blocks_by_work.lower_bound(invalid_walk_tip->pprev->nChainWork);
         while (candidate_it != candidate_blocks_by_work.end()) {
@@ -3783,7 +3815,6 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
         to_mark_failed->nStatus |= BLOCK_FAILED_VALID;
         m_blockman.m_dirty_blockindex.insert(to_mark_failed);
         setBlockIndexCandidates.erase(to_mark_failed);
-        m_chainman.m_failed_blocks.insert(to_mark_failed);
 
         // If any new blocks somehow arrived while we were disconnecting
         // (above), then the pre-calculation of what should go into
@@ -3849,7 +3880,6 @@ void Chainstate::ResetBlockFailureFlags(CBlockIndex *pindex) {
                 // Reset invalid block marker if it was pointing to one of those.
                 m_chainman.m_best_invalid = nullptr;
             }
-            m_chainman.m_failed_blocks.erase(&block_index);
         }
     }
 
@@ -3858,7 +3888,6 @@ void Chainstate::ResetBlockFailureFlags(CBlockIndex *pindex) {
         if (pindex->nStatus & BLOCK_FAILED_MASK) {
             pindex->nStatus &= ~BLOCK_FAILED_MASK;
             m_blockman.m_dirty_blockindex.insert(pindex);
-            m_chainman.m_failed_blocks.erase(pindex);
         }
         pindex = pindex->pprev;
     }
@@ -4362,45 +4391,6 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
             LogDebug(BCLog::VALIDATION, "%s: Consensus::ContextualCheckBlockHeader: %s, %s\n", __func__, hash.ToString(), state.ToString());
             return false;
         }
-
-        /* Determine if this block descends from any block which has been found
-         * invalid (m_failed_blocks), then mark pindexPrev and any blocks between
-         * them as failed. For example:
-         *
-         *                D3
-         *              /
-         *      B2 - C2
-         *    /         \
-         *  A             D2 - E2 - F2
-         *    \
-         *      B1 - C1 - D1 - E1
-         *
-         * In the case that we attempted to reorg from E1 to F2, only to find
-         * C2 to be invalid, we would mark D2, E2, and F2 as BLOCK_FAILED_CHILD
-         * but NOT D3 (it was not in any of our candidate sets at the time).
-         *
-         * In any case D3 will also be marked as BLOCK_FAILED_CHILD at restart
-         * in LoadBlockIndex.
-         */
-        if (!pindexPrev->IsValid(BLOCK_VALID_SCRIPTS)) {
-            // The above does not mean "invalid": it checks if the previous block
-            // hasn't been validated up to BLOCK_VALID_SCRIPTS. This is a performance
-            // optimization, in the common case of adding a new block to the tip,
-            // we don't need to iterate over the failed blocks list.
-            for (const CBlockIndex* failedit : m_failed_blocks) {
-                if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) {
-                    assert(failedit->nStatus & BLOCK_FAILED_VALID);
-                    CBlockIndex* invalid_walk = pindexPrev;
-                    while (invalid_walk != failedit) {
-                        invalid_walk->nStatus |= BLOCK_FAILED_CHILD;
-                        m_blockman.m_dirty_blockindex.insert(invalid_walk);
-                        invalid_walk = invalid_walk->pprev;
-                    }
-                    LogDebug(BCLog::VALIDATION, "header %s has prev block invalid: %s\n", hash.ToString(), block.hashPrevBlock.ToString());
-                    return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk");
-                }
-            }
-        }
     }
     if (!min_pow_checked) {
         LogDebug(BCLog::VALIDATION, "%s: not adding new block header %s, missing anti-dos proof-of-work validation\n", __func__, hash.ToString());
@@ -4545,6 +4535,7 @@ bool ChainstateManager::AcceptBlock(const std::shared_ptr<const CBlock>& pblock,
         if (state.IsInvalid() && state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
             pindex->nStatus |= BLOCK_FAILED_VALID;
             m_blockman.m_dirty_blockindex.insert(pindex);
+            ActiveChainstate().InvalidChainFound(pindex);
         }
         LogError("%s: %s\n", __func__, state.ToString());
         return false;
@@ -5286,6 +5277,7 @@ void ChainstateManager::CheckBlockIndex()
     // are not yet validated.
     CChain best_hdr_chain;
     assert(m_best_header);
+    assert(!(m_best_header->nStatus & BLOCK_FAILED_MASK));
     best_hdr_chain.SetTip(*m_best_header);
 
     std::multimap<CBlockIndex*,CBlockIndex*> forward;
@@ -5399,6 +5391,8 @@ void ChainstateManager::CheckBlockIndex()
         if (pindexFirstInvalid == nullptr) {
             // Checks for not-invalid blocks.
             assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
+        } else {
+            assert((pindex->nStatus & BLOCK_FAILED_MASK)); // Descendants of invalid blocks must also be marked as invalid
         }
         // Make sure m_chain_tx_count sum is correctly computed.
         if (!pindex->pprev) {
@@ -5412,6 +5406,8 @@ void ChainstateManager::CheckBlockIndex()
             // block, and must be set if it is.
             assert((pindex->m_chain_tx_count != 0) == (pindex == snap_base));
         }
+        // There should be no block with more work than m_best_header, unless it's known to be invalid
+        assert((pindex->nStatus & BLOCK_FAILED_MASK) || pindex->nChainWork <= m_best_header->nChainWork);
 
         // Chainstate-specific checks on setBlockIndexCandidates
         for (auto c : GetAll()) {

src/validation.h

@@ -1038,27 +1038,6 @@ public:
     }
 
 
-    /**
-     * In order to efficiently track invalidity of headers, we keep the set of
-     * blocks which we tried to connect and found to be invalid here (ie which
-     * were set to BLOCK_FAILED_VALID since the last restart). We can then
-     * walk this set and check if a new header is a descendant of something in
-     * this set, preventing us from having to walk m_block_index when we try
-     * to connect a bad block and fail.
-     *
-     * While this is more complicated than marking everything which descends
-     * from an invalid block as invalid at the time we discover it to be
-     * invalid, doing so would require walking all of m_block_index to find all
-     * descendants. Since this case should be very rare, keeping track of all
-     * BLOCK_FAILED_VALID blocks in a set should be just fine and work just as
-     * well.
-     *
-     * Because we already walk m_block_index in height-order at startup, we go
-     * ahead and mark descendants of invalid blocks as FAILED_CHILD at that time,
-     * instead of putting things in this set.
-     */
-    std::set<CBlockIndex*> m_failed_blocks;
-
     /** Best header we've seen so far (used for getheaders queries' starting points). */
     CBlockIndex* m_best_header GUARDED_BY(::cs_main){nullptr};