diff --git a/nixos/modules/system/boot/systemd/initrd.nix b/nixos/modules/system/boot/systemd/initrd.nix
index ecdb6b58de77..8cf575eb61ad 100644
--- a/nixos/modules/system/boot/systemd/initrd.nix
+++ b/nixos/modules/system/boot/systemd/initrd.nix
@@ -108,8 +108,9 @@ let
   fileSystems = filter utils.fsNeededForBoot config.system.build.fileSystems;
 
   fstab = pkgs.writeText "fstab" (lib.concatMapStringsSep "\n"
-    ({ fsType, mountPoint, device, options, ... }:
-      "${device} /sysroot${mountPoint} ${fsType} ${lib.concatStringsSep "," options}") fileSystems);
+    ({ fsType, mountPoint, device, options, autoFormat, autoResize, ... }@fs: let
+        opts = options ++ optional autoFormat "x-systemd.makefs" ++ optional autoResize "x-systemd.growfs";
+      in "${device} /sysroot${mountPoint} ${fsType} ${lib.concatStringsSep "," opts}") fileSystems);
 
   kernel-name = config.boot.kernelPackages.kernel.name or "kernel";
   modulesTree = config.system.modulesTree.override { name = kernel-name + "-modules"; };
@@ -294,7 +295,7 @@ in {
   config = mkIf (config.boot.initrd.enable && cfg.enable) {
     system.build = { inherit initialRamdisk; };
     boot.initrd.systemd = {
-      initrdBin = [pkgs.bash pkgs.coreutils pkgs.kmod cfg.package];
+      initrdBin = [pkgs.bash pkgs.coreutils pkgs.kmod cfg.package] ++ config.system.fsPackages;
 
       objects = [
         { object = "${cfg.package}/lib/systemd/systemd"; symlink = "/init"; }
@@ -357,6 +358,21 @@ in {
         // listToAttrs (map
                      (v: let n = escapeSystemdPath v.where;
                          in nameValuePair "${n}.automount" (automountToUnit n v)) cfg.automounts);
+
+      # The unit in /run/systemd/generator shadows the unit in
+      # /etc/systemd/system, but will still apply drop-ins from
+      # /etc/systemd/system/foo.service.d/
+      #
+      # We need IgnoreOnIsolate, otherwise the Requires dependency of
+      # a mount unit on its makefs unit causes it to be unmounted when
+      # we isolate for switch-root. Use a dummy package so that
+      # generateUnits will generate drop-ins instead of unit files.
+      packages = [(pkgs.runCommand "dummy" {} ''
+        mkdir -p $out/etc/systemd/system
+        touch $out/etc/systemd/system/systemd-{makefs,growfs}@.service
+      '')];
+      services."systemd-makefs@".unitConfig.IgnoreOnIsolate = true;
+      services."systemd-growfs@".unitConfig.IgnoreOnIsolate = true;
     };
   };
 }
diff --git a/nixos/modules/tasks/filesystems.nix b/nixos/modules/tasks/filesystems.nix
index f3da6771197e..6fcc762ca88c 100644
--- a/nixos/modules/tasks/filesystems.nix
+++ b/nixos/modules/tasks/filesystems.nix
@@ -323,7 +323,7 @@ in
             unitConfig.DefaultDependencies = false; # needed to prevent a cycle
             serviceConfig.Type = "oneshot";
           };
-      in listToAttrs (map formatDevice (filter (fs: fs.autoFormat) fileSystems)) // {
+      in listToAttrs (map formatDevice (filter (fs: fs.autoFormat && !(utils.fsNeededForBoot fs)) fileSystems)) // {
     # Mount /sys/fs/pstore for evacuating panic logs and crashdumps from persistent storage onto the disk using systemd-pstore.
     # This cannot be done with the other special filesystems because the pstore module (which creates the mount point) is not loaded then.
         "mount-pstore" = {
diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index f8653a6f34a8..05738b9cfc1b 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -923,6 +923,8 @@ in
       mkVMOverride (cfg.fileSystems //
       {
         "/".device = cfg.bootDevice;
+        "/".fsType = "ext4";
+        "/".autoFormat = true;
 
         "/tmp" = mkIf config.boot.tmpOnTmpfs
           { device = "tmpfs";