how-to-have-root-n-user-share-dir.md

A way to provide root and regular user to share a full r/w directory without using symbolic links

At home directory

$ pwd
/home/oyuksel

Create a file to be used as shared disk (e.g. 200 MB)

$ dd if=/dev/zero of=dualmount.img bs=200M count=1

Create ext4 fs on it

mkfs.ext4 dualmount.img

Create dir to "mount to" for regular user

$ mkdir /home/oyuksel/dualmount

Create dir to "mount to" for root

# mkdir /root/dualmount

Update /etc/fstab for mounts with allows. Add lines:

/home/oyuksel/dualmount.img     /home/oyuksel/dualmount ext4    loop,user,noauto       0 0
/home/oyuksel/dualmount.img     /root/dualmount ext4    loop,user,noauto       0 0

Mount as root

# mount /root/dualmount

Create a shared dir and change owner

# mkdir /root/dualmount/shared_dir
# chown oyuksel. /root/dualmount/shared_dir

Mount as regular user

$ mount /home/oyuksel/dualmount

Test access as regular user

$ touch /home/oyuksel/dualmount/shared_dir/newfile01

Check from root side

# ls -l /root/dualmount/shared_dir
total 0
-rw-rw-r-- 1 oyuksel oyuksel 0 Jan 18 17:37 newfile01
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