[Borgbackup] Restore

[Thomas Waldmann]

In save_config, borg tries to save the repo config in the most secure 
and safe way:

1. ln config config.old  # create a hardlink to old file contents
2. save -> config  # save new file contents in a very safe way
3. secure_erase config.old  # secure erase old file contents from disk

3 is done because there could be a repokey in the config and maybe you 
just have changed the key passphrase. Then you would not want the key 
protected by the old passphrase to be accessible via some "undelete" tool.

And at 3. it ran into an issue on your system:

>>   File "/usr/lib64/python3.10/site-packages/borg/repository.py", line 
>> 332, in save_config
>>     secure_erase(old_config_path, avoid_collateral_damage=True)
>>   File "/usr/lib64/python3.10/site-packages/borg/helpers/fs.py", line 
>> 199, in secure_erase
>>     with open(path, 'r+b') as fd:
>> OSError: [Errno 5] Input/output error: '/mnt/rs1219a/SRV/config.old'

As I already noted, an I/O error is something below borg.

Often, it is a hardware issue, but it could be also a malfunctioning 
driver or filesystem.