Why does my nfs mount always changes to be owned by root after mounting?

Question

I have a mount point for my nfs share:

drwxrwxrwx   2 patryk patryk 4.0K Feb  4 16:23 nfs_share

after I mount it I get

$ sudo mount -t nfs 10.9.XXX.XXX:/root/src /home/patryk/nfs_share -o rw,user,vers=3 
drwxr-xr-x   2 root   root   4.0K Feb  4 17:06 nfs_share

I tried with /etc/fstab but I get the same results:

10.9.XXX.XXX:/root/src /home/patryk/nfs_share nfs rw,user,vers=3 0 0

The funny thing is that I cannot chown this after mounting:

$ sudo chown patryk:patryk nfs_share
chown: changing ownership of `nfs_share': Operation not permitted

My server is configured as follows:

// 10.9.XXX.XXX
$ cat /etc/exports
/root/src/napet_src/ *(rw,nohide,insecure,no_subtree_check,async)

How do I define those permissions so that I can write to this folder?

Solution

You need to add uid (user identifier) and guid (group user identifier) like these:

$ sudo mount -t nfs 10.9.XXX.XXX:/root/src /home/patryk/nfs_share -o rw,user,vers=3,uid=1001,gid=1001

Maybe you need to use id command to find your id/guid:

$ id username

Although you may use actual user/groupnames (beware of spaces) instead numeric uid, gid values.

Comments

[Louis Kröger]

You can also just specify uid=user,gid=user and mount will figure out the current user's credentials, if that's what you need.

[bagustris]

For Ubuntu 20.04, the comment above didn't work (the answer did). Error message: "'uid' option needs a decimal value"