diff --git a/include/dwarfs/scanner.h b/include/dwarfs/scanner.h
index c0cdd51a..2150f1c9 100644
--- a/include/dwarfs/scanner.h
+++ b/include/dwarfs/scanner.h
@@ -32,6 +32,7 @@ namespace dwarfs {
 struct scanner_options;
 
 class entry_factory;
+class file_access;
 class filesystem_writer;
 class logger;
 class os_access;
@@ -47,11 +48,11 @@ class scanner {
           std::shared_ptr<os_access const> os, std::shared_ptr<script> scr,
           const scanner_options& options);
 
-  void scan(filesystem_writer& fsw, const std::filesystem::path& path,
-            progress& prog,
-            std::optional<std::span<std::filesystem::path const>> list =
-                std::nullopt) {
-    impl_->scan(fsw, path, prog, list);
+  void scan(
+      filesystem_writer& fsw, const std::filesystem::path& path, progress& prog,
+      std::optional<std::span<std::filesystem::path const>> list = std::nullopt,
+      std::shared_ptr<file_access const> fa = nullptr) {
+    impl_->scan(fsw, path, prog, list, fa);
   }
 
   class impl {
@@ -61,7 +62,8 @@ class scanner {
     virtual void
     scan(filesystem_writer& fsw, const std::filesystem::path& path,
          progress& prog,
-         std::optional<std::span<std::filesystem::path const>> list) = 0;
+         std::optional<std::span<std::filesystem::path const>> list,
+         std::shared_ptr<file_access const> fa) = 0;
   };
 
  private:
diff --git a/src/dwarfs/scanner.cpp b/src/dwarfs/scanner.cpp
index 0f0fa410..1e3320dd 100644
--- a/src/dwarfs/scanner.cpp
+++ b/src/dwarfs/scanner.cpp
@@ -43,6 +43,7 @@
 #include "dwarfs/entry.h"
 #include "dwarfs/error.h"
 #include "dwarfs/features.h"
+#include "dwarfs/file_access.h"
 #include "dwarfs/file_scanner.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/fragment_chunkable.h"
@@ -279,10 +280,10 @@ class scanner_ final : public scanner::impl {
            std::shared_ptr<os_access const> os, std::shared_ptr<script> scr,
            const scanner_options& options);
 
-  void
-  scan(filesystem_writer& fsw, std::filesystem::path const& path,
-       progress& prog,
-       std::optional<std::span<std::filesystem::path const>> list) override;
+  void scan(filesystem_writer& fsw, std::filesystem::path const& path,
+            progress& prog,
+            std::optional<std::span<std::filesystem::path const>> list,
+            std::shared_ptr<file_access const> fa) override;
 
  private:
   std::shared_ptr<entry> scan_tree(std::filesystem::path const& path,
@@ -564,7 +565,8 @@ scanner_<LoggerPolicy>::scan_list(std::filesystem::path const& path,
 template <typename LoggerPolicy>
 void scanner_<LoggerPolicy>::scan(
     filesystem_writer& fsw, const std::filesystem::path& path, progress& prog,
-    std::optional<std::span<std::filesystem::path const>> list) {
+    std::optional<std::span<std::filesystem::path const>> list,
+    std::shared_ptr<file_access const> fa) {
   if (!options_.debug_filter_function) {
     LOG_INFO << "scanning " << path;
   }
@@ -659,8 +661,23 @@ void scanner_<LoggerPolicy>::scan(
     });
   });
 
-  if (getenv_is_enabled("DWARFS_DUMP_INODES")) {
-    im.dump(std::cout);
+  if (auto dumpfile = os_->getenv("DWARFS_DUMP_INODES")) {
+    if (fa) {
+      LOG_VERBOSE << "dumping inodes to " << *dumpfile;
+      std::error_code ec;
+      auto ofs = fa->open_output(*dumpfile, ec);
+      if (ec) {
+        LOG_ERROR << "cannot open '" << *dumpfile << "': " << ec.message();
+      } else {
+        im.dump(ofs->os());
+        ofs->close(ec);
+        if (ec) {
+          LOG_ERROR << "cannot close '" << *dumpfile << "': " << ec.message();
+        }
+      }
+    } else {
+      LOG_ERROR << "cannot dump inodes: no file access";
+    }
   }
 
   LOG_INFO << "building blocks...";
diff --git a/src/mkdwarfs_main.cpp b/src/mkdwarfs_main.cpp
index 2ecf4b4a..cd0afdf7 100644
--- a/src/mkdwarfs_main.cpp
+++ b/src/mkdwarfs_main.cpp
@@ -1258,11 +1258,7 @@ int mkdwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
       scanner s(lgr, wg_scanner, std::move(sf), entry_factory::create(), iol.os,
                 std::move(script), options);
 
-      if (input_list) {
-        s.scan(*fsw, path, prog, *input_list);
-      } else {
-        s.scan(*fsw, path, prog);
-      }
+      s.scan(*fsw, path, prog, input_list, iol.file);
 
       options.inode.categorizer_mgr.reset();
     }