After upgrading from Mageia 5 to 6, I discovered that "/usr/lib/cups/backend/smb" was a dangling link, so printing failed for a printer accessed via SMB protocol.
The link referenced "/etc/alternatives/smb", which referenced "/usr/lib/cups/backend/smb3" from samba-client-3.6.25-2.7.mga5.
In Mageia 6, samba-client-4.6.5-1.mga6 contains "/usr/libexec/samba/cups_backend_smb".
When I did "ln -svf /usr/libexec/samba/cups_backend_smb /usr/lib/cups/backend/smb", printing worked again.
Moreover, I found several other dangling links related to samba3 in "/etc/alternatives/" but those links where not referenced elsewhere.
Assigning to the registered samba maintainer
Problem with SMB backend for CUPS =>
Problem with SMB backend for CUPS, caused by /usr/lib/cups/backend/smb danging link
Bug confirmed here :
and workaround also confirmed. Thanks Nicolas.
We need now a packager to correct the problem.