Persistent FileSystem Issue

[Jeffery Sarenpa]

Hello Everyone,

We are running into a very strange issue, that we can't seem to wrap our heads around. Google support wasn't able to help, and our submitted chromium issue hasn't gotten any replies for almost 2 weeks (https://code.google.com/p/chromium/issues/detail?id=474605).

This problem is occurring on our Chromeboxes that we are running in kiosk mode (enterprise enrolled as well). This is the sequence of events:

• We enroll a Chromebox as an enterprise enrolled device, and place it in the correct organization with our kiosk app designated to run in single-app kiosk mode.
  
• The application itself is roughly 5MB in size, and only contains the structure of the application.
  
• Once the application downloads and installs, our custom built libraries download a little over 1GB of asset files (videos, images, etc) that make up the core content of the kiosk.
  
• These files are saved to persistent storage using the FileSystem API (detailed here: http://www.html5rocks.com/en/tutorials/file/filesystem/).
  
• Everything will work perfectly fine for days. Data will persist through reboots of the device. It will also persist through updates of the kiosk application.
  
• Randomly (we haven't found any pattern whatsoever), one day, the kiosk will lose the ability to store files persistently. Once that happens and we restart that kiosk, no files will be found in the file system, and everything will have to be downloaded again.
  
• Once this random issue occurs, no files will persist in the file system over the course of many days/restarts.
  
• Randomly (again, we haven't found any pattern whatsoever), one day, the kiosk will regain the ability to store files persistently.
  
• This pattern repeats seemingly forever. After an indeterminate amount of days, the Chromebox will lose the ability to store files persistently, and after another indeterminate amount of days, the Chromebox will regain its ability to store files persistently.

A few other things to note:

• We have tried creating an extremely simple kiosk application, that basically just writes a file to the file system, restarts the device, and tries to read the file again. This process is repeated over and over again. This application produces the same problem after days of working perfectly.
• We have tried this on Chromeboxes running Chrome OS versions all the way from 38 to 42, with the same results.
• We have tried this on 2 different brands of Chromeboxes, trying to rule out potential hardware anomalies.
• When using the app on a desktop computer or another device that is NOT in kiosk mode, the problem does not occur.

Based on all of these factors, we think it is a bug in chromium itself pertaining to the file system api in kiosk mode. Here are the things we are working on testing right now:

1. We are attempting to use NaCL (https://developer.chrome.com/native-client/nacl-and-pnacl) to make all file system calls in kiosk mode. We're theorizing that the File I/O api for NaCL (https://developer.chrome.com/native-client/devguide/coding/file-io) is calling lower level code than the javascript file system api. Does anyone know if this is the case?

We are truly at a loss here and would appreciate any help/suggestions.

If you have any further questions about the issue please ask.

Thanks!

[Jeffery Sarenpa]

All further discussion can be directed here: https://code.google.com/p/chromium/issues/detail?id=474605