umask ignored on NFSv4.2 mounts

Bug #1779736 reported by Michael Shannon on 2018-07-02
This bug affects 5 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
nfs-utils (Ubuntu)

Bug Description

After upgrading to kernel 4.15.0-24-generic (on Ubuntu 18.04 LTS) NFSv4.2 mounts ignore the umask when creating files and directories. Files get permissions 666 and directories get 777. Therefore, a umask of 000 is seemingly being forced when creating files/directories in NFS mounts. Mounting with noacl does not resolve the issue.

How to replicate:

1. Mount an NFS share (defaults to NFSv4.2)
2. Ensure restrictive umask: umask 022
3. Create directory: mkdir test_dir
4. Create file: touch test_file
5. List: ls -l

The result will be:
drwxrwxrwx 2 user user 2 Jul 2 12:16 test_dir
-rw-rw-rw- 1 user user 0 Jul 2 12:16 test_file

while the expected result would be
drwxr-xr-x 2 user user 2 Jul 2 12:16 test_dir
-rw-r--r-- 1 user user 0 Jul 2 12:16 test_file

Bug does not occur when mounting with any of:

I have a suspicion this is related to:
But since the server does not have ACL's enabled, and mounting with noacl does not resolve the issue this is unexpected behavior.

Both server and client are running kernel 4.15.0-24-generic on Ubuntu 18.04 LTS. NFS package versions are:

nfs-kernel-server 1:1.3.4-2.1ubuntu5
nfs-common 1:1.3.4-2.1ubuntu5

description: updated
description: updated
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in nfs-utils (Ubuntu):
status: New → Confirmed
Quentin (quantumhpc) wrote :

As a workaround/fix, the umask is respected if you set the acl to the zfs exported pool"
zfs set acltype=posixacl ...

W. Michael Petullo (mike-flyn) wrote :

I am having a similar problem on Fedora, but the documentation is sparse. As a workaround, I presently mount using NFSv4.1 rather than 4.2. I can neither find precise documentation on (1) what is going on nor (2) how to restore the behavior where the process umask comes into play when creating a file or directory.

See also

Scott Emmons (lscotte) wrote :

I can confirm this issue, on Ubuntu Bionic - server is 4.15.0-43-generic, client is 4.15.0-45-generic. Server filesystem is ZFS (using nfs-kernel-server for export). Mounting with vers=4.1 works around it as noted above.

Changed in linux (Ubuntu):
status: New → Confirmed
Mason Loring Bliss (y-mason) wrote :

I can confirm that "zfs set acltype=posixacl foo/bar/" is an effective workaround. It appears to be
unset by default.

root@box /root# zfs set acltype=posixacl pool/srv/thing
root@box /root# zfs get acltype pool/srv
pool/srv acltype off default
root@box /root# zfs get acltype pool/srv/thing
pool/srv/thing acltype posixacl local

Thanks, Quentin.

Luis Felipe Marzagao (dulinux) wrote :

I can confirm setting acltype to posixacl on the dataset shared via NFS fixes the issue.

Databay (rs-databay) wrote :

Same for me, setting posixacl on ZFS exported via NFS is a workaround

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