A Lack of Host Dir/File Write Permission Behaviors Need Improvements

[imanabu]

How To Repro the Issue

1. Start with the docker image
2. Mount the host's folder with only a read only permission to everyone to s3 ninja's mount point.
3. Log into http://localhost:9444/ui
4. Create a bucket

What you will see

• The UI indicates a success of bucket creation
• But it does not show file addition UI
• There appears to be nothing logged in the docker console

What I expected to see

• Good: At a minimum I wanted to see if there was a permission error in the docker's console.
• Better: The bucket creation UI response should have shown you an error message instead of success
• Best: The bucket error message would indicate there was a file permission error.

Note that if the write permission is given to the directory, it will work perfectly.