Previously working proxmox-backup-client command now fails

[Fischer-HWH]

Hi,

I have been using proxmox-backup-client to create backups, which I can write to tapes.
It's a pretty simple setup where I have a few SMB shares mounted locally (on the PBS itself), and then run a command in the style of (names changed obviously):

proxmox-backup-client backup archive1.pxar:/mnt/remotefolder1 archive2.pxar:/mnt/remotefolder2 archive3.pxar:/mnt/remotefolder3

This exact command was used in the past and was working fine, but it's now been not working for over a year, so I thought I'd ask here. Last successful run was august 2023.
Additionally, environment variables PBS_PASSWORD_FILE and PBS_REPOSITORY are set (the latter just contains the name of the datastore). Something about the file access seems to fail and it won't tell me where or with what path or anything. The shares are mounted read-only, but they always have been and it was fine.

Output is from the command looks as follows:

Starting backup: host/MyPbsHostname/2025-03-19T13:51:42Z
Client name: MyPbsHostname
Starting backup protocol: Wed Mar 19 14:51:42 2025
storing login ticket failed: $XDG_RUNTIME_DIR must be set
Downloading previous manifest (Thu Aug 31 11:03:53 2023)
Upload directory '/mnt/remotefolder1' to 'archive' as archive1.pxar.didx
catalog upload error - channel closed
Error: failed to get metadata for source directory

Caused by:
    0: failed to read xattrs
    1: EACCES: Permission denied

 

[Chris]

Error: failed to get metadata for source directory

This part of the error message suggests that you lack permissions on this

'/mnt/remotefolder1'

folder.

Check the output of stat /mnt/remotefolder1, and getfacl /mnt/remotefolder1. Also check getfattr /mnt/remotefolder1

 

[Fischer-HWH]

This part of the error message suggests that you lack permissions on this folder.

I have permissions on the folder. This was run as root, and the folder is mounted as root. I can list contents, read files. The shares come from a Windows host. I have a .pxarexclude, which I can also cat just fine. It excludes the usual (System Volume Information and $RECYCLE.BIN). I did spot-check for a bit, and I can read all files I tried, and list all folders. They aren't system-partitions, but all of them just contain data (so no Windows, ProgramData or Users folders on any of the shares)

Check the output of stat /mnt/remotefolder1, and getfacl /mnt/remotefolder1. Also check getfattr /mnt/remotefolder1

Output below.

# stat /mnt/remotefolder1/
  File: /mnt/remotefolder1/
  Size: 8192            Blocks: 16         IO Block: 1048576 directory
Device: 0,54    Inode: 1407374883553285  Links: 2
Access: (0755/drwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2024-04-23 19:12:35.927161600 +0200
Modify: 2024-04-23 19:12:35.927161600 +0200
Change: 2024-04-23 19:12:35.927161600 +0200
Birth: 2022-05-08 00:24:03.228098500 +0200

I had to install acl and attr to get the remaining commands. Output below.

# getfacl /mnt/remotefolder1
getfacl: Removing leading '/' from absolute path names
# file: mnt/remotefolder1
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

#getfattr /mnt/remotefolder1
getfattr: /mnt/remotefolder1: Permission denied

So how or why does that fail, exactly? And why is it suddenly a problem NOW, when it was working a fine a while ago? I mean I can't really give myself more permissions: I'm already root with owner and group also set to root and rwx set as well. The folders/shares are mounted from fstab with an entry roughly looking like:

//ActualFileServer/remotefolder1   /mnt/remotefolder1  cifs credentials=/root/.smbcredentials,uid=0,gid=0,ro 0 0

The Windows-User used to access the share has read permission, and again it's mounted readonly anyway as it's just meant to be read and written to the backup.