--- cvs-fast-export-1.66/atom.c.orig	2024-04-07 15:44:05.728144147 +0200
+++ cvs-fast-export-1.66/atom.c	2024-04-07 15:49:33.189703469 +0200
@@ -100,24 +100,24 @@ const char *atom(const char *string)
 	hash_bucket_t *b;
 	int len;
 
+#ifdef THREADS
+	if (threads > 1) {
+		pthread_mutex_lock(&bucket_mutex);
+	}
+#endif /* THREADS */
 	while ((b = *head)) {
 	collision:
 		if (b->hash == hash && !strcmp(string, b->string)) {
+#ifdef THREADS
+			if (threads > 1) {
+				pthread_mutex_unlock(&bucket_mutex);
+			}
+#endif /* THREADS */
 			return b->string;
 		}
 		head = &(b->next);
 	}
-#ifdef THREADS
-	if (threads > 1) {
-		pthread_mutex_lock(&bucket_mutex);
-	}
-#endif /* THREADS */
 	if ((b = *head)) {
-#ifdef THREADS
-		if (threads > 1) {
-			pthread_mutex_unlock(&bucket_mutex);
-		}
-#endif /* THREADS */
 		goto collision;
 	}
 
@@ -157,24 +157,24 @@ const cvs_number *atom_cvs_number(const
 	number_bucket_t **head = &number_buckets[bucket];
 	number_bucket_t *b;
 
+#ifdef THREADS
+	if (threads > 1) {
+		pthread_mutex_lock(&number_bucket_mutex);
+	}
+#endif /* THREADS */
 	while ((b = *head)) {
 	collision:
 		if (cvs_number_equal(&b->number, &n)) {
+#ifdef THREADS
+			if (threads > 1) {
+				pthread_mutex_unlock(&number_bucket_mutex);
+			}
+#endif /* THREADS */
 			return &b->number;
 		}
 		head = &(b->next);
 	}
-#ifdef THREADS
-	if (threads > 1) {
-		pthread_mutex_lock(&number_bucket_mutex);
-	}
-#endif /* THREADS */
 	if ((b = *head)) {
-#ifdef THREADS
-		if (threads > 1) {
-			pthread_mutex_unlock(&number_bucket_mutex);
-		}
-#endif /* THREADS */
 		goto collision;
 	}
 
--- cvs-fast-export-1.66/revcvs.c.orig	2024-04-07 15:44:05.731477463 +0200
+++ cvs-fast-export-1.66/revcvs.c	2024-04-07 15:56:06.944236984 +0200
@@ -22,6 +22,9 @@
 #endif
 
 const master_dir *root_dir = NULL;
+#ifdef THREADS
+static pthread_mutex_t root_dir_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
 
 static const char *fileop_name(const char *rectified) {
 	size_t rlen = strlen(rectified);
@@ -79,24 +82,24 @@ static const master_dir *atom_dir(const
 	dir_bucket **head = &dir_buckets[HASH_VALUE(dirname) % DIR_BUCKETS];
 	dir_bucket *b;
 
+#ifdef THREADS
+	if (threads > 1) {
+		pthread_mutex_lock(&dir_bucket_mutex);
+	}
+#endif /* THREADS */
 	while ((b = *head)) {
 	collision:
 		if (b->dir.name == dirname) {
+#ifdef THREADS
+			if (threads > 1) {
+				pthread_mutex_unlock(&dir_bucket_mutex);
+			}
+#endif /* THREADS */
 			return &(b->dir);
 		}
 		head = &(b->next);
 	}
-#ifdef THREADS
-	if (threads > 1) {
-		pthread_mutex_lock(&dir_bucket_mutex);
-	}
-#endif /* THREADS */
 	if ((b = *head)) {
-#ifdef THREADS
-		if (threads > 1) {
-			pthread_mutex_unlock(&dir_bucket_mutex);
-		}
-#endif /* THREADS */
 		goto collision;
 	}
 	b = xmalloc(sizeof(dir_bucket), __func__);
@@ -859,9 +862,17 @@ cvs_commit *cvs_master_digest(cvs_file *
 	cvs_branch *cb;
 	cvs_version *ctrunk = NULL;
 
+#ifdef THREADS
+    if (threads > 1)
+	pthread_mutex_lock(&root_dir_mutex);
+#endif
 	if (!root_dir) {
 		root_dir = atom_dir(atom("\0"));
 	}
+#ifdef THREADS
+    if (threads > 1)
+	pthread_mutex_unlock(&root_dir_mutex);
+#endif
 	build_rev_master(cvs, master);
 #if CVSDEBUG
 	char buf[CVS_MAX_REV_LEN];