From 3e9308eb0eb97ee8444335602e59a46dce885c64 Mon Sep 17 00:00:00 2001
From: Leo Yuriev <leo@yuriev.ru>
Date: Tue, 19 Dec 2017 16:38:12 +0300
Subject: [PATCH] mdbx: check for running write-txn inside mdbx_env_close().

---
 mdbx.h     |  2 +-
 src/mdbx.c | 10 +++++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/mdbx.h b/mdbx.h
index c1de5e39..8df5f4a3 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -754,7 +754,7 @@ LIBMDBX_API int mdbx_env_sync(MDBX_env *env, int force);
  *                 ignored on opening next time, and transactions since the
  *                 last non-weak checkpoint (meta-page update) will rolledback
  *                 for consistency guarantee. */
-LIBMDBX_API void mdbx_env_close(MDBX_env *env);
+LIBMDBX_API int mdbx_env_close(MDBX_env *env);
 
 /* Set environment flags.
  *
diff --git a/src/mdbx.c b/src/mdbx.c
index 15c2ad04..6d25c03d 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -5387,8 +5387,12 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
   if (unlikely(env->me_signature != MDBX_ME_SIGNATURE))
     return MDBX_EBADSIGN;
 
-  if (!dont_sync && !(env->me_flags & MDBX_RDONLY))
-    rc = mdbx_env_sync(env, true);
+  if ((env->me_flags & MDBX_RDONLY) == 0) {
+    if (env->me_txn0->mt_owner && env->me_txn0->mt_owner != mdbx_thread_self())
+      return MDBX_BUSY;
+    if (!dont_sync)
+      rc = mdbx_env_sync(env, true);
+  }
 
   VALGRIND_DESTROY_MEMPOOL(env);
   while ((dp = env->me_dpages) != NULL) {
@@ -5406,7 +5410,7 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
   return rc;
 }
 
-void __cold mdbx_env_close(MDBX_env *env) { mdbx_env_close_ex(env, 0); }
+int mdbx_env_close(MDBX_env *env) { return mdbx_env_close_ex(env, 0); }
 
 /* Compare two items pointing at aligned unsigned int's. */
 static int __hot mdbx_cmp_int_ai(const MDBX_val *a, const MDBX_val *b) {