s3fs is a simple tool to mount s3 buckets.  What i found was when you moant s3 bucket on a machine it will mount with 700 which means other users even root can't access it. So i tried chmod on the mount point and ended up with this error.

$ sudo chmod /home/ubuntu/s3_bucket
chmod: changing permissions of '/home/ubuntu/s3_bucket': Input/output error

I spent some time on s3fs tool and found that we need to add a parameter while mounting "-o allow_other", let see

old command was 

$ sudo s3fs -o use_cache=/tmp/s3_cache  s3_bucket

new command is 

$ sudo s3fs -o use_cache=/tmp/s3_cache -o allow_other  s3_bucket

Then my bucket got mounted with 777 permissions.