From 18379c80874ad6f4fa0e962dd2046e2fa7ecd287 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sun, 27 Jan 2013 00:22:15 +0100
Subject: [PATCH] Add disk space checks before flushing CCoins cache

---
 src/main.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index 1d881c0a..2b4acccb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1806,6 +1806,13 @@ bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
     // Make sure it's successfully written to disk before changing memory structure
     bool fIsInitialDownload = IsInitialBlockDownload();
     if (!fIsInitialDownload || pcoinsTip->GetCacheSize() > nCoinCacheSize) {
+        // Typical CCoins structures on disk are around 100 bytes in size.
+        // Pushing a new one to the database can cause it to be written
+        // twice (once in the log, and once in the tables). This is already
+        // an overestimation, as most will delete an existing entry or
+        // overwrite one. Still, use a conservative safety factor of 2.
+        if (!CheckDiskSpace(100 * 2 * 2 * pcoinsTip->GetCacheSize()))
+            return state.Error();
         FlushBlockFile();
         pblocktree->Sync();
         if (!pcoinsTip->Flush())