[validation] RewindBlockIndex no longer needed

Instead of rewinding blocks, we request that the user restarts with
-reindex

1 files changed, 8 insertions, 20 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 584b148aff..a1c026f806 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1698,29 +1698,17 @@ bool AppInitMain(const util::Ref& context, NodeContext& node, interfaces::BlockA
                 break;
             }
 
-            bool failed_rewind{false};
-            // Can't hold cs_main while calling RewindBlockIndex, so retrieve the relevant
-            // chainstates beforehand.
-            for (CChainState* chainstate : WITH_LOCK(::cs_main, return chainman.GetAll())) {
-                if (!fReset) {
-                    // Note that RewindBlockIndex MUST run even if we're about to -reindex-chainstate.
-                    // It both disconnects blocks based on the chainstate, and drops block data in
-                    // BlockIndex() based on lack of available witness data.
-                    uiInterface.InitMessage(_("Rewinding blocks...").translated);
-                    if (!chainstate->RewindBlockIndex(chainparams)) {
-                        strLoadError = _(
-                            "Unable to rewind the database to a pre-fork state. "
-                            "You will need to redownload the blockchain");
-                        failed_rewind = true;
-                        break; // out of the per-chainstate loop
-                    }
+            if (!fReset) {
+                LOCK(cs_main);
+                auto chainstates{chainman.GetAll()};
+                if (std::any_of(chainstates.begin(), chainstates.end(),
+                                [&chainparams](const CChainState* cs) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return cs->NeedsRedownload(chainparams); })) {
+                    strLoadError = strprintf(_("Witness data for blocks after height %d requires validation. Please restart with -reindex."),
+                                             chainparams.GetConsensus().SegwitHeight);
+                    break;
                 }
             }
 
-            if (failed_rewind) {
-                break; // out of the chainstate activation do-while
-            }
-
             bool failed_verification = false;
 
             try {