I am running Parallels Desktop 7 on OS X Lion. I have a VM with Debian installed, and inside that VM I setup a Rails development environment. I am using Parallels Tools to share out my OS X home directory to the VM - the goal here is to run the Rails server on the VM, but host the files on OS X (so they are automatically backed up, and so I can use tools like Textmate to develop with).

Everything seems to work with the shared directory - my Debian user can read, write, and execute files. However, when I cloned a recent Rails project from Git, I got an error message when it tried to compile the CSS assets. My symptoms are exactly the same as in the question: http://stackoverflow.com/questions/7556774/rails-sprocket-error-compiling-css-assest-chown-issue

I believe this is permissions-based, but it is really weird. My entire Rails project directory has permissions set to 777 and my Debian user owns it. If I navigate into /tmp/cache/assets, those permissions are the same. However, the three-character directories Rails is creating (DCE, DA1, D05, etc...) are being created without write permissions!

If I refresh the Rails page a few times, about 4 or 5 (with Rails creating new three-character directories every time), eventually it will create one of the directories with the proper 777 permissions and everything will work! This will persist until I make a change to the CSS files and it has to recompile.

Does anyone have any idea what might be going on here? I can't fathom why it is creating temp directories with incorrect permissions, or why after a few refreshes the good permissions kick in and it works...

It definitely seems to be an issue with the share, since if I move the project into a different directory on the VM, it seems to work fine. On the OS X side, I've given the shared folder 777 permissions as well, but no dice...any ideas?

Update
I've found that the number of times I need to refresh before it works is not random - it has to do with how many assets are being compiled. For example, if I edit one of my CSS files, and there are four CSS files in the app/assets/stylesheets directory, I have to refresh four times before the app will finally work without the operation not permitted error...