Screwed up permissions, ownership, attributes on large fs. How to reset? (lemmy.dbzer0.com)

submitted 1 week ago* (last edited 1 week ago) by [email protected] to c/[email protected]

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I have been playing around with chmod, chown, setfacl and special bits trying to get multiple system/full users in same group correct access permissions to my media collection.

But I've messed it up somehow and now I'm having weird problems that are hard to track.

I would like to set my whole collection back to the defaults.

What is the best way to do this?

One problem I've had when making changes to so many files is the process seems to go forever without completing. Eventually it gets killed so my filesystem has variable attributes throughout. how can this be worked around?

I want everything to be owned by myuser, group media, everything else default I will sort it from there once I have a fresh slate.

And is there a way to backup these attributes only? I don't have enough storage to backup the files themselves.

It is Debian with ext4 filesystem.

Edit to add: Media collection is on its own separate drive/filesystem; this has no impact on anything else on the computer.

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[-] [email protected] 1 points 1 week ago

can you share the script?

[-] [email protected] 2 points 1 week ago

Yeah. Only on my phone right now but will get it and post here later/tomorrow.

[-] [email protected] 1 points 1 week ago

OK so it's fairly simple. You need to install the acl package (or whatever equivalent package contains getfacl/setfacl. Then you can use that to dump the data from an entire structure into a file (I also then bzip that). Then I backup all installed packages to help with a restore too.

So the script looks like:

#!/bin/bash
cd /etc
/usr/bin/getfacl -R . | /usr/bin/bzip2 -9 >PERMISSION_BACKUP.bz2
chmod 600 PERMISSION_BACKUP.bz2
cd /home
/usr/bin/getfacl -R . | /usr/bin/bzip2 -9 >PERMISSION_BACKUP.bz2
chmod 600 PERMISSION_BACKUP.bz2
cd /root
/usr/bin/getfacl -R . | /usr/bin/bzip2 -9 >PERMISSION_BACKUP.bz2
chmod 600 PERMISSION_BACKUP.bz2
cd /var
/usr/bin/getfacl -R . | /usr/bin/bzip2 -9 >PERMISSION_BACKUP.bz2
chmod 600 PERMISSION_BACKUP.bz2
/usr/bin/apt list --installed | /usr/bin/bzip2 -9 >/root/INSTALLED-PACKAGES.bz2
chmod 600 /root/INSTALLED-PACKAGES.bz2

To restore you change to the folder the backup was taken from, unbzip the file (or uncompress live via pipe) and use setfacl --restore=

[-] [email protected] 1 points 1 week ago

thanks for getting back to me. :)

I am curious what kind of situation would screw up your /etc/ directory?

[-] [email protected] 1 points 1 week ago

It's for backup purposes mainly. A lot of cloud backup providers don't store permissions.

So if I restore the data I can then restore the permissions after. So these are the folders I am backing up (with some exceptions in /var)

[-] [email protected] 1 points 1 week ago

Ah I see. Thanks! The data and the attributes are stored separately.

this post was submitted on 24 May 2025

35 points (94.9% liked)

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