Mount option mode

[CMCDragonkai]

When creating a dataset for /tmp in ZFS, I expected that there would be a mode option to set like mode=1777. Currently ZFS doesn't have this option under zfs mount, but neither does normal mount command:

# this doesn't work
mount -t zfs -o mode=1777 rpool/tmp /mnt/tmp

Any reasons why there's no mode option for ZFS?

[dasjoe]

A dataset's permissions are preserved, you can set them manually once and they'll be restored at the next mount:

# zfs create sbooblehat-rpool/test
# ls -al /
[…]
drwxr-xr-x   2 root root        2 Dec 14 14:35 test
[…]
# chmod 1777 /test
# ls -al /
[…]
drwxrwxrwt   2 root root        2 Dec 14 14:35 test
[…]
# zfs umount /test
# rm -r /test
# zfs mount sbooblehat-rpool/test 
# ls -al /
[…]
drwxrwxrwt   2 root root        2 Dec 14 14:35 test
[…]

[CMCDragonkai]

Oh that's handy. What's storing the state of that?

[behlendorf]

@CMCDragonkai they're stored in the root inode for the dataset.