diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 37d846ad0108..6aab9ce59560 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -42,6 +42,7 @@
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/DOMTypes.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/dom/FileBlobImpl.h"
 #include "mozilla/dom/HTMLMediaElement.h"
 #include "mozilla/dom/HTMLTemplateElement.h"
@@ -7885,6 +7886,19 @@ nsContentUtils::TransferableToIPCTransferable(nsITransferable* aTransferable,
               continue;
             }
 
+            if (aParent) {
+              bool isDir = false;
+              if (NS_SUCCEEDED(file->IsDirectory(&isDir)) && isDir) {
+                nsAutoString path;
+                if (NS_WARN_IF(NS_FAILED(file->GetPath(path)))) {
+                  continue;
+                }
+
+                RefPtr<FileSystemSecurity> fss = FileSystemSecurity::GetOrCreate();
+                fss->GrantAccessToContentProcess(aParent->ChildID(), path);
+              }
+            }
+
             blobImpl = new FileBlobImpl(file);
 
             IgnoredErrorResult rv;
diff --git a/dom/filesystem/FileSystemRequestParent.cpp b/dom/filesystem/FileSystemRequestParent.cpp
index 25125b65dfb4..af4359b84436 100644
--- a/dom/filesystem/FileSystemRequestParent.cpp
+++ b/dom/filesystem/FileSystemRequestParent.cpp
@@ -10,8 +10,12 @@
 #include "GetDirectoryListingTask.h"
 #include "GetFileOrDirectoryTask.h"
 
+#include "mozilla/dom/ContentParent.h"
 #include "mozilla/dom/FileSystemBase.h"
+#include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/ipc/BackgroundParent.h"
+#include "mozilla/Unused.h"
+#include "nsProxyRelease.h"
 
 using namespace mozilla::ipc;
 
@@ -69,14 +73,104 @@ FileSystemRequestParent::Initialize(const FileSystemParams& aParams)
   return true;
 }
 
+namespace {
+
+class CheckPermissionRunnable final : public Runnable
+{
+public:
+  CheckPermissionRunnable(already_AddRefed<ContentParent> aParent,
+                          FileSystemRequestParent* aActor,
+                          FileSystemTaskParentBase* aTask,
+                          const nsAString& aPath)
+    : mContentParent(aParent)
+    , mActor(aActor)
+    , mTask(aTask)
+    , mPath(aPath)
+    , mBackgroundEventTarget(NS_GetCurrentThread())
+  {
+    AssertIsInMainProcess();
+    AssertIsOnBackgroundThread();
+
+    MOZ_ASSERT(mContentParent);
+    MOZ_ASSERT(mActor);
+    MOZ_ASSERT(mTask);
+    MOZ_ASSERT(mBackgroundEventTarget);
+  }
+
+  NS_IMETHOD
+  Run() override
+  {
+    if (NS_IsMainThread()) {
+      auto raii = mozilla::MakeScopeExit([&] { mContentParent = nullptr; });
+
+
+      if (!mozilla::Preferences::GetBool("dom.filesystem.pathcheck.disabled", false)) {
+        RefPtr<FileSystemSecurity> fss = FileSystemSecurity::Get();
+        if (NS_WARN_IF(!fss ||
+                       !fss->ContentProcessHasAccessTo(mContentParent->ChildID(),
+                                                       mPath))) {
+          mContentParent->KillHard("This path is not allowed.");
+          return NS_OK;
+        }
+      }
+
+      return mBackgroundEventTarget->Dispatch(this, NS_DISPATCH_NORMAL);
+    }
+
+    AssertIsOnBackgroundThread();
+
+    // It can happen that this actor has been destroyed in the meantime we were
+    // on the main-thread.
+    if (!mActor->Destroyed()) {
+      mTask->Start();
+    }
+
+    return NS_OK;
+  }
+
+private:
+  ~CheckPermissionRunnable()
+  {
+     NS_ProxyRelease(mBackgroundEventTarget, mActor.forget());
+  }
+
+  RefPtr<ContentParent> mContentParent;
+  RefPtr<FileSystemRequestParent> mActor;
+  RefPtr<FileSystemTaskParentBase> mTask;
+  const nsString mPath;
+
+  nsCOMPtr<nsIEventTarget> mBackgroundEventTarget;
+};
+
+} // anonymous
+
 void
 FileSystemRequestParent::Start()
 {
+  AssertIsInMainProcess();
+  AssertIsOnBackgroundThread();
+
   MOZ_ASSERT(!mDestroyed);
   MOZ_ASSERT(mFileSystem);
   MOZ_ASSERT(mTask);
 
-  mTask->Start();
+  nsAutoString path;
+  if (NS_WARN_IF(NS_FAILED(mTask->GetTargetPath(path)))) {
+    Unused << Send__delete__(this, FileSystemErrorResponse(NS_ERROR_DOM_SECURITY_ERR));
+    return;
+  }
+
+  RefPtr<ContentParent> parent = BackgroundParent::GetContentParent(Manager());
+
+  // If the ContentParent is null we are dealing with a same-process actor.
+  if (!parent) {
+    mTask->Start();
+    return;
+  }
+
+  RefPtr<Runnable> runnable =
+    new CheckPermissionRunnable(parent.forget(), this, mTask, path);
+  NS_DispatchToMainThread(runnable);
 }
 
 void
diff --git a/dom/filesystem/FileSystemSecurity.cpp b/dom/filesystem/FileSystemSecurity.cpp
new file mode 100644
index 000000000000..56f8a74e8013
--- /dev/null
+++ b/dom/filesystem/FileSystemSecurity.cpp
@@ -0,0 +1,107 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FileSystemSecurity.h"
+#include "FileSystemUtils.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/StaticPtr.h"
+
+namespace mozilla {
+namespace dom {
+
+namespace {
+
+StaticRefPtr<FileSystemSecurity> gFileSystemSecurity;
+
+} // anonymous
+
+/* static */ already_AddRefed<FileSystemSecurity>
+FileSystemSecurity::Get()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
+  RefPtr<FileSystemSecurity> service = gFileSystemSecurity.get();
+  return service.forget();
+}
+
+/* static */ already_AddRefed<FileSystemSecurity>
+FileSystemSecurity::GetOrCreate()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
+  if (!gFileSystemSecurity) {
+    gFileSystemSecurity = new FileSystemSecurity();
+    ClearOnShutdown(&gFileSystemSecurity);
+  }
+
+  RefPtr<FileSystemSecurity> service = gFileSystemSecurity.get();
+  return service.forget();
+}
+
+FileSystemSecurity::FileSystemSecurity()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+}
+
+FileSystemSecurity::~FileSystemSecurity()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+}
+
+void
+FileSystemSecurity::GrantAccessToContentProcess(ContentParentId aId,
+                                                const nsAString& aDirectoryPath)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
+  nsTArray<nsString>* paths;
+  if (!mPaths.Get(aId, &paths)) {
+    paths = new nsTArray<nsString>();
+    mPaths.Put(aId, paths);
+  } else if (paths->Contains(aDirectoryPath)) {
+    return;
+  }
+
+  paths->AppendElement(aDirectoryPath);
+}
+
+void
+FileSystemSecurity::Forget(ContentParentId aId)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
+  mPaths.Remove(aId);
+}
+
+bool
+FileSystemSecurity::ContentProcessHasAccessTo(ContentParentId aId,
+                                              const nsAString& aPath)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  AssertIsInMainProcess();
+
+  nsTArray<nsString>* paths;
+  if (!mPaths.Get(aId, &paths)) {
+    return false;
+  }
+
+  for (uint32_t i = 0, len = paths->Length(); i < len; ++i) {
+    if (FileSystemUtils::IsDescendantPath(paths->ElementAt(i), aPath)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+} // dom namespace
+} // mozilla namespace
diff --git a/dom/filesystem/FileSystemSecurity.h b/dom/filesystem/FileSystemSecurity.h
new file mode 100644
index 000000000000..fe61dc7c6dc6
--- /dev/null
+++ b/dom/filesystem/FileSystemSecurity.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_FileSystemSecurity_h
+#define mozilla_dom_FileSystemSecurity_h
+
+#include "mozilla/dom/ipc/IdType.h"
+#include "nsClassHashtable.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+namespace dom {
+
+class FileSystemSecurity final
+{
+public:
+  NS_INLINE_DECL_REFCOUNTING(FileSystemSecurity)
+
+  static already_AddRefed<FileSystemSecurity>
+  Get();
+
+  static already_AddRefed<FileSystemSecurity>
+  GetOrCreate();
+
+  void
+  GrantAccessToContentProcess(ContentParentId aId,
+                              const nsAString& aDirectoryPath);
+
+  void
+  Forget(ContentParentId aId);
+
+  bool
+  ContentProcessHasAccessTo(ContentParentId aId, const nsAString& aPath);
+
+private:
+  FileSystemSecurity();
+  ~FileSystemSecurity();
+
+  nsClassHashtable<nsUint64HashKey, nsTArray<nsString>> mPaths;
+};
+
+} // dom namespace
+} // mozilla namespace
+
+#endif // mozilla_dom_FileSystemSecurity_h
diff --git a/dom/filesystem/FileSystemTaskBase.h b/dom/filesystem/FileSystemTaskBase.h
index 03e9f2090c27..0435587711f8 100644
--- a/dom/filesystem/FileSystemTaskBase.h
+++ b/dom/filesystem/FileSystemTaskBase.h
@@ -231,6 +231,9 @@ public:
   NS_IMETHOD
   Run() override;
 
+  virtual nsresult
+  GetTargetPath(nsAString& aPath) const = 0;
+
 private:
   /*
    * Wrap the task result to FileSystemResponseValue for sending it through IPC.
diff --git a/dom/filesystem/FileSystemUtils.cpp b/dom/filesystem/FileSystemUtils.cpp
index 490c1f810820..872e049ee1cc 100644
--- a/dom/filesystem/FileSystemUtils.cpp
+++ b/dom/filesystem/FileSystemUtils.cpp
@@ -20,24 +20,12 @@ TokenizerIgnoreNothing(char16_t /* aChar */)
 } // anonymous namespace
 
 /* static */ bool
-FileSystemUtils::IsDescendantPath(nsIFile* aFile,
-                                  nsIFile* aDescendantFile)
+FileSystemUtils::IsDescendantPath(const nsAString& aPath,
+                                  const nsAString& aDescendantPath)
 {
-  nsAutoString path;
-  nsresult rv = aFile->GetPath(path);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return false;
-  }
-
-  nsAutoString descendantPath;
-  rv = aDescendantFile->GetPath(descendantPath);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return false;
-  }
-
   // Check the sub-directory path to see if it has the parent path as prefix.
-  if (descendantPath.Length() <= path.Length() ||
-      !StringBeginsWith(descendantPath, path)) {
+  if (!aDescendantPath.Equals(aPath) &&
+      !StringBeginsWith(aDescendantPath, aPath)) {
     return false;
   }
 
diff --git a/dom/filesystem/FileSystemUtils.h b/dom/filesystem/FileSystemUtils.h
index 2285bdc1c56f..ae302e07ca6c 100644
--- a/dom/filesystem/FileSystemUtils.h
+++ b/dom/filesystem/FileSystemUtils.h
@@ -26,7 +26,8 @@ public:
    * Return true if aDescendantPath is a descendant of aPath.
    */
   static bool
-  IsDescendantPath(nsIFile* aPath, nsIFile* aDescendantPath);
+  IsDescendantPath(const nsAString& aPath,
+                   const nsAString& aDescendantPath);
 
   /**
    * Return true if this is valid DOMPath. It also splits the path in
diff --git a/dom/filesystem/GetDirectoryListingTask.cpp b/dom/filesystem/GetDirectoryListingTask.cpp
index 25ca8685ffc1..081e3f354b6c 100644
--- a/dom/filesystem/GetDirectoryListingTask.cpp
+++ b/dom/filesystem/GetDirectoryListingTask.cpp
@@ -380,5 +380,11 @@ GetDirectoryListingTaskParent::IOWork()
   return NS_OK;
 }
 
+nsresult
+GetDirectoryListingTaskParent::GetTargetPath(nsAString& aPath) const
+{
+  return mTargetPath->GetPath(aPath);
+}
+
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/filesystem/GetDirectoryListingTask.h b/dom/filesystem/GetDirectoryListingTask.h
index 764ce478919b..7692c8bae54d 100644
--- a/dom/filesystem/GetDirectoryListingTask.h
+++ b/dom/filesystem/GetDirectoryListingTask.h
@@ -69,6 +69,9 @@ public:
          FileSystemRequestParent* aParent,
          ErrorResult& aRv);
 
+  nsresult
+  GetTargetPath(nsAString& aPath) const override;
+
 private:
   GetDirectoryListingTaskParent(FileSystemBase* aFileSystem,
                                 const FileSystemGetDirectoryListingParams& aParam,
diff --git a/dom/filesystem/GetFileOrDirectoryTask.cpp b/dom/filesystem/GetFileOrDirectoryTask.cpp
index 7f721bc63375..15d0baf88d38 100644
--- a/dom/filesystem/GetFileOrDirectoryTask.cpp
+++ b/dom/filesystem/GetFileOrDirectoryTask.cpp
@@ -270,5 +270,11 @@ GetFileOrDirectoryTaskParent::IOWork()
   return NS_OK;
 }
 
+nsresult
+GetFileOrDirectoryTaskParent::GetTargetPath(nsAString& aPath) const
+{
+  return mTargetPath->GetPath(aPath);
+}
+
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/filesystem/GetFileOrDirectoryTask.h b/dom/filesystem/GetFileOrDirectoryTask.h
index 28a9fc9354f2..2a53df158fad 100644
--- a/dom/filesystem/GetFileOrDirectoryTask.h
+++ b/dom/filesystem/GetFileOrDirectoryTask.h
@@ -62,6 +62,9 @@ public:
          FileSystemRequestParent* aParent,
          ErrorResult& aRv);
 
+  nsresult
+  GetTargetPath(nsAString& aPath) const override;
+
 protected:
   virtual FileSystemResponseValue
   GetSuccessRequestResult(ErrorResult& aRv) const override;
diff --git a/dom/filesystem/GetFilesTask.cpp b/dom/filesystem/GetFilesTask.cpp
index 02f0d538e260..cf3c12cef853 100644
--- a/dom/filesystem/GetFilesTask.cpp
+++ b/dom/filesystem/GetFilesTask.cpp
@@ -253,5 +253,11 @@ GetFilesTaskParent::IOWork()
   return NS_OK;
 }
 
+nsresult
+GetFilesTaskParent::GetTargetPath(nsAString& aPath) const
+{
+  return mTargetPath->GetPath(aPath);
+}
+
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/filesystem/GetFilesTask.h b/dom/filesystem/GetFilesTask.h
index 348b0c552c84..be08a5d189c6 100644
--- a/dom/filesystem/GetFilesTask.h
+++ b/dom/filesystem/GetFilesTask.h
@@ -71,6 +71,9 @@ public:
          FileSystemRequestParent* aParent,
          ErrorResult& aRv);
 
+  nsresult
+  GetTargetPath(nsAString& aPath) const override;
+
 private:
   GetFilesTaskParent(FileSystemBase* aFileSystem,
                      const FileSystemGetFilesParams& aParam,
diff --git a/dom/filesystem/compat/tests/test_basic.html b/dom/filesystem/compat/tests/test_basic.html
index 1dff09c5d481..0ce6e6926ef9 100644
--- a/dom/filesystem/compat/tests/test_basic.html
+++ b/dom/filesystem/compat/tests/test_basic.html
@@ -16,6 +16,7 @@ var script;
 
 function setup_tests() {
   SpecialPowers.pushPrefEnv({"set": [["dom.webkitBlink.dirPicker.enabled", true],
+                                     ["dom.filesystem.pathcheck.disabled", true],
                                      ["dom.webkitBlink.filesystem.enabled", true]]}, next);
 }
 
diff --git a/dom/filesystem/compat/tests/test_formSubmission.html b/dom/filesystem/compat/tests/test_formSubmission.html
index 57a37d190f69..c920dcce1460 100644
--- a/dom/filesystem/compat/tests/test_formSubmission.html
+++ b/dom/filesystem/compat/tests/test_formSubmission.html
@@ -32,6 +32,7 @@ function setup_tests() {
 
   SpecialPowers.pushPrefEnv({"set": [["dom.input.dirpicker", true],
                                      ["dom.webkitBlink.dirPicker.enabled", true],
+                                     ["dom.filesystem.pathcheck.disabled", true],
                                      ["dom.webkitBlink.filesystem.enabled", true]]}, next);
 }
 
diff --git a/dom/filesystem/compat/tests/test_no_dnd.html b/dom/filesystem/compat/tests/test_no_dnd.html
index 5554d442b012..4ddaaf33012d 100644
--- a/dom/filesystem/compat/tests/test_no_dnd.html
+++ b/dom/filesystem/compat/tests/test_no_dnd.html
@@ -16,6 +16,7 @@ var entries;
 
 function setup_tests() {
   SpecialPowers.pushPrefEnv({"set": [["dom.webkitBlink.dirPicker.enabled", true],
+                                     ["dom.filesystem.pathcheck.disabled", true],
                                      ["dom.webkitBlink.filesystem.enabled", true]]}, next);
 }
 
diff --git a/dom/filesystem/moz.build b/dom/filesystem/moz.build
index fa215ba9693b..bf32c9c56e58 100644
--- a/dom/filesystem/moz.build
+++ b/dom/filesystem/moz.build
@@ -15,6 +15,7 @@ EXPORTS.mozilla.dom += [
     'Directory.h',
     'FileSystemBase.h',
     'FileSystemRequestParent.h',
+    'FileSystemSecurity.h',
     'FileSystemTaskBase.h',
     'FileSystemUtils.h',
     'GetFilesHelper.h',
@@ -25,6 +26,7 @@ UNIFIED_SOURCES += [
     'Directory.cpp',
     'FileSystemBase.cpp',
     'FileSystemRequestParent.cpp',
+    'FileSystemSecurity.cpp',
     'FileSystemTaskBase.cpp',
     'FileSystemUtils.cpp',
     'GetDirectoryListingTask.cpp',
diff --git a/dom/filesystem/tests/filesystem_commons.js b/dom/filesystem/tests/filesystem_commons.js
index b9ebc2d7334f..4f7234121e74 100644
--- a/dom/filesystem/tests/filesystem_commons.js
+++ b/dom/filesystem/tests/filesystem_commons.js
@@ -11,6 +11,7 @@ function createRelativePath(parentDir, dirOrFile) {
 function setup_tests(aNext) {
   SimpleTest.requestLongerTimeout(2);
   SpecialPowers.pushPrefEnv({"set": [["dom.input.dirpicker", true],
+                                     ["dom.filesystem.pathcheck.disabled", true],
                                      ["dom.webkitBlink.dirPicker.enabled", true]]}, aNext);
 }
 
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index a9a9d74db63c..dd4f94618e36 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -41,6 +41,7 @@
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/File.h"
 #include "mozilla/dom/FileCreatorHelper.h"
+#include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/dom/ExternalHelperAppParent.h"
 #include "mozilla/dom/GetFilesHelper.h"
 #include "mozilla/dom/GeolocationBinding.h"
@@ -1680,6 +1681,11 @@ ContentParent::ActorDestroy(ActorDestroyReason why)
     mHangMonitorActor = nullptr;
   }
 
+  RefPtr<FileSystemSecurity> fss = FileSystemSecurity::Get();
+  if (fss) {
+    fss->Forget(ChildID());
+  }
+
   if (why == NormalShutdown && !mCalledClose) {
     // If we shut down normally but haven't called Close, assume somebody
     // else called Close on us. In that case, we still need to call
diff --git a/dom/ipc/FilePickerParent.cpp b/dom/ipc/FilePickerParent.cpp
index 7d9346e7bbe4..f37e3695ddf5 100644
--- a/dom/ipc/FilePickerParent.cpp
+++ b/dom/ipc/FilePickerParent.cpp
@@ -13,6 +13,7 @@
 #include "nsISimpleEnumerator.h"
 #include "mozilla/Unused.h"
 #include "mozilla/dom/FileBlobImpl.h"
+#include "mozilla/dom/FileSystemSecurity.h"
 #include "mozilla/dom/ContentParent.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/TabParent.h"
@@ -145,6 +146,8 @@ FilePickerParent::IORunnable::Destroy()
 void
 FilePickerParent::SendFilesOrDirectories(const nsTArray<BlobImplOrString>& aData)
 {
+  nsIContentParent* parent = TabParent::GetFrom(Manager())->Manager();
+
   if (mMode == nsIFilePicker::modeGetFolder) {
     MOZ_ASSERT(aData.Length() <= 1);
     if (aData.IsEmpty()) {
@@ -154,13 +157,18 @@ FilePickerParent::SendFilesOrDirectories(const nsTArray<BlobImplOrString>& aData
 
     MOZ_ASSERT(aData[0].mType == BlobImplOrString::eDirectoryPath);
 
+    // Let's inform the security singleton about the given access of this tab on
+    // this directory path.
+    RefPtr<FileSystemSecurity> fss = FileSystemSecurity::GetOrCreate();
+    fss->GrantAccessToContentProcess(parent->ChildID(),
+                                     aData[0].mDirectoryPath);
+
     InputDirectory input;
     input.directoryPath() = aData[0].mDirectoryPath;
     Unused << Send__delete__(this, input, mResult);
     return;
   }
 
-  nsIContentParent* parent = TabParent::GetFrom(Manager())->Manager();
   InfallibleTArray<PBlobParent*> blobs;
 
   for (unsigned i = 0; i < aData.Length(); i++) {
diff --git a/ipc/glue/BackgroundParentImpl.cpp b/ipc/glue/BackgroundParentImpl.cpp
index d2ddce4d93f6..0532ac43951e 100644
--- a/ipc/glue/BackgroundParentImpl.cpp
+++ b/ipc/glue/BackgroundParentImpl.cpp
@@ -787,11 +787,18 @@ BackgroundParentImpl::AllocPFileSystemRequestParent(
     return nullptr;
   }
 
-  result->Start();
-
   return result.forget().take();
 }
 
+mozilla::ipc::IPCResult
+BackgroundParentImpl::RecvPFileSystemRequestConstructor(
+                                               PFileSystemRequestParent* aActor,
+                                               const FileSystemParams& params)
+{
+  static_cast<FileSystemRequestParent*>(aActor)->Start();
+  return IPC_OK();
+}
+
 bool
 BackgroundParentImpl::DeallocPFileSystemRequestParent(
                                               PFileSystemRequestParent* aDoomed)
diff --git a/ipc/glue/BackgroundParentImpl.h b/ipc/glue/BackgroundParentImpl.h
index adce87536bc4..eeda791c879c 100644
--- a/ipc/glue/BackgroundParentImpl.h
+++ b/ipc/glue/BackgroundParentImpl.h
@@ -193,6 +193,10 @@ protected:
   virtual PFileSystemRequestParent*
   AllocPFileSystemRequestParent(const FileSystemParams&) override;
 
+  virtual mozilla::ipc::IPCResult
+  RecvPFileSystemRequestConstructor(PFileSystemRequestParent* actor,
+                                    const FileSystemParams& params) override;
+
   virtual bool
   DeallocPFileSystemRequestParent(PFileSystemRequestParent*) override;