Data directory check fails in the installation process for NFS mounts

[SamJia]

Steps to reproduce

1. download nextcloud server archive, extract all the files into the document root directory of Apache2
2. mount external NFS to datadir
3. visit the Nextcloud webpage. In the setup process, enter datadir into the Data folder section.
4. Click Finish setup, then it prompt 'Can't create or write into the data directory datadir'

Server configuration

Operating system: Ubuntu 18.04

Web server: Apache2

Database: Mysql 5.7

PHP version: 7.2

Nextcloud version: (see Nextcloud admin page) 16.0.1

Updated from an older Nextcloud/ownCloud or fresh install: fresh install

Where did you install Nextcloud from: download the archive from 'https://nextcloud.com/install/#instructions-server'

Troubleshooting

This error occurs because of line 302~304 of /lib/private/Setup.php. In the function install, it will validate the data directory. However, there are some bugs of the function is_writable facing NFS mounts.

In /lib/private/legacy/util.php, about line 793, there is a comment that is_writable doesn't work for NFS mounts, so try to write a file and check if it exists. So I think the function is_writable should not be used in this project. Or maybe we can write a new function in this project to check whether a directory is writable or not by trying to write a file.

Now I fix it by commenting line 302~304 of Setup.php. However, the function is_writable is called 19 times in 9 files:

• /lib/base.php
• /lib/private/Files/Storage/Local.php
• /lib/private/IntegrityCheck/Checker.php
• /lib/private/IntegrityCheck/Helpers/FileAccessHelper.php
• /lib/private/legacy/image.php
• /lib/private/legacy/util.php
• /lib/private/Log/File.php
• /lib/private/Setup.php
• /lib/private/TempManager.php

I'm not sure if there will be some other bugs because of the usage of this function. I think we can consider replacing all the is_writable in these files to our own writability check function.

[Subnet-Masked]

I am having a similar issue after setup. I have recently moved my data directory to a mounted NFS share, and I am getting thousands of data_dir_writability_test errors in my logs... Everything seems to be working though.

There are some other mentions of these issues in #7124 and #13237, but they have both been resolved for previous versions of Nextcloud...

[Subnet-Masked]

I have posted a similar issue at #26016 for nextcloud 20.0.8

[szaimen]

Is this Issue still valid in NC21.0.2? If not, please close this issue. Thanks! :)

This issue has been automatically marked as stale because it has not had recent activity and seems to be missing some essential information. It will be closed if no further activity occurs. Thank you for your contributions.

[smarwei]

For me it mounting the data dir via NFS (synology) still doesn't work correctly. I could create and edit files from within the web interface, but uploading or deleting files didn't work.
I now mount the directory with samba which works just fine.