further changes after discussions

app/controllers/concerns/uploads_actions.rb

@@ -76,4 +76,12 @@ module UploadsActions
   def image_or_video?
     uploader && uploader.exists? && uploader.image_or_video?
   end
+
+  def find_model
+    nil
+  end
+
+  def model
+    strong_memoize(:model) { find_model }
+  end
 end

app/controllers/groups/uploads_controller.rb

@@ -26,8 +26,4 @@ class Groups::UploadsController < Groups::ApplicationController
   def authorize_upload_file!
     render_404 unless can?(current_user, :upload_file, group)
   end
-
-  def model
-    @model ||= find_model
-  end
 end

app/controllers/projects/uploads_controller.rb

@@ -25,8 +25,4 @@ class Projects::UploadsController < Projects::ApplicationController
 
     Project.find_by_full_path("#{namespace}/#{id}")
   end
-
-  def model
-    @model || find_model
-  end
 end

app/controllers/uploads_controller.rb

@@ -28,7 +28,7 @@ class UploadsController < ApplicationController
   def find_model
     return nil unless params[:id]
 
-    @model = upload_model_class.find(params[:id])
+    upload_model_class.find(params[:id])
   end
 
   def authorize_access!
@@ -81,8 +81,4 @@ class UploadsController < ApplicationController
 
     upload_model_class.uploader_options.has_key?(upload_mount)
   end
-
-  def model
-    @model ||= find_model
-  end
 end

config/gitlab.yml.example

@@ -176,7 +176,7 @@ production: &base
 
   ## Uploads (attachments, avatars, etc...)
   uploads:
-    # The location where LFS objects are stored (default: shared/lfs-objects).
+    # The location where uploads objects are stored (default: public/).
     # storage_path: public/
     # base_dir: uploads/-/system
     object_store:

doc/development/file_storage.md

@@ -93,7 +93,7 @@ The `CarrierWave::Uploader#store_dir` is overriden to
 
 > Note: this concern will automatically include `RecordsUploads::Concern` if not already included.
 
-The `ObjectStorage::Concern` uploader will search for the correct `Upload` in the model's `uploads` relationship to select the correct object store. A basic implementation of the `ObjectStorage:: The `Upload` is mapped using the `RecordsUploads::Concern#upload_path` for each store (LOCAL/REMOTE).
+The `ObjectStorage::Concern` uploader will search for the matching `Upload` to select the correct object store. The `Upload` is mapped using `#store_dirs + identifier` for each store (LOCAL/REMOTE).
 
 ```ruby
 class SongUploader < GitlabUploader
@@ -114,6 +114,7 @@ end
 ### Using a mounted uploader
 
 The `ObjectStorage::Concern` will query the `model.<mount>_store` attribute to select the correct object store.
+This column must be present in the model schema.
 
 ```ruby
 class SongUploader < GitlabUploader
@@ -127,7 +128,7 @@ class Thing < ActiveRecord::Base
   mount :theme, SongUploader # we have a great theme song!
 
   def theme_store
-    super || ObjectStorage::Store::REMOTE # send new files to object store
+    super || ObjectStorage::Store::LOCAL
   end
 
   ...