Merge branch 'fix-writable-shell' of https://github.com/yorickvP/nix

src/libstore/filetransfer.cc

@@ -544,6 +544,14 @@ struct curlFileTransfer : public FileTransfer
             stopWorkerThread();
         });
 
+#ifdef __linux__
+        /* Cause this thread to not share any FS attributes with the main thread,
+           because this causes setns() in restoreMountNamespace() to fail.
+           Ideally, this would happen in the std::thread() constructor. */
+        if (unshare(CLONE_FS) != 0)
+            throw SysError("unsharing filesystem state in download thread");
+#endif
+
         std::map<CURL *, std::shared_ptr<TransferItem>> items;
 
         bool quit = false;

src/libstore/local-store.cc

@@ -504,6 +504,7 @@ void LocalStore::makeStoreWritable()
         throw SysError("getting info about the Nix store mount point");
 
     if (stat.f_flag & ST_RDONLY) {
+        saveMountNamespace();
         if (unshare(CLONE_NEWNS) == -1)
             throw SysError("setting up a private mount namespace");