diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index fd104dffd9..4c03da3e2c 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1211,10 +1211,16 @@ void DerivationGoal::computeClosure()
 }
 
 
+static string drvsLogDir = "drvs";
+
+
 void DerivationGoal::openLogFile()
 {
     /* Create a log file. */
-    Path logFileName = nixLogDir + "/drvs/" + baseNameOf(drvPath);
+    Path dir = (format("%1%/%2%") % nixLogDir % drvsLogDir).str();
+    createDirs(dir);
+    
+    Path logFileName = (format("%1%/%2%") % dir % baseNameOf(drvPath)).str();
     fdLogFile = open(logFileName.c_str(),
         O_CREAT | O_WRONLY | O_TRUNC, 0666);
     if (fdLogFile == -1)
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index e1075d0251..7f0b079467 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -43,16 +43,6 @@ static int openGCLock(LockType lockType)
 }
 
 
-static void createDirs(const Path & path)
-{
-    if (path == "") return;
-    createDirs(dirOf(path));
-    if (!pathExists(path))
-        if (mkdir(path.c_str(), 0777) == -1)
-            throw SysError(format("creating directory `%1%'") % path);
-}
-
-
 void createSymlink(const Path & link, const Path & target, bool careful)
 {
     /* Create directories up to `gcRoot'. */
@@ -122,8 +112,11 @@ void addTempRoot(const Path & path)
     if (fdTempRoots == -1) {
 
         while (1) {
-            fnTempRoots = (format("%1%/%2%/%3%")
-                % nixStateDir % tempRootsDir % getpid()).str();
+            Path dir = (format("%1%/%2%") % nixStateDir % tempRootsDir).str();
+            createDirs(dir);
+            
+            fnTempRoots = (format("%1%/%2%")
+                % dir % getpid()).str();
 
             AutoCloseFD fdGCLock = openGCLock(ltRead);
             
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 27df7a1aaa..65c3b15397 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -271,6 +271,16 @@ Path createTempDir()
 }
 
 
+void createDirs(const Path & path)
+{
+    if (path == "") return;
+    createDirs(dirOf(path));
+    if (!pathExists(path))
+        if (mkdir(path.c_str(), 0777) == -1)
+            throw SysError(format("creating directory `%1%'") % path);
+}
+
+
 void writeStringToFile(const Path & path, const string & s)
 {
     AutoCloseFD fd(open(path.c_str(),
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 2577f79e1b..beb98fe7c6 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -107,6 +107,9 @@ void makePathReadOnly(const Path & path);
 /* Create a temporary directory. */
 Path createTempDir();
 
+/* Create a directory and all its parents, if necessary. */
+void createDirs(const Path & path);
+
 /* Create a file and write the given text to it.  The file is written
    in binary mode (i.e., no end-of-line conversions).  The path should
    not already exist. */