[PATCH 0/8][focal:linux, groovy:linux] cifs: On cifs_reconnect, resolve the hostname again

[Tim Gardner]

BugLink: https://bugs.launchpad.net/bugs/1929831

Microsoft has asked to have commit commit 4e456b30f78c429b183db420e23b26cde7e03a78 applied.
A customer is reporting difficulties, though details are quite sparse.
The first 3 patches are scaffolding to make the backport simpler.

These patches were commited between 5.9 and 5.11, so only focal and groovy are affected.

These patches have been released with focal:linux-azure after having solved the issue
for the Microsoft customer. They are suitable for the mainline kernels.

[Impact]

CIFS reconnects fail.

[Test Plan]

A test kernel made available to Microsoft has been verified to fix the problem.

[Where problems could occur]

This could perturb CIFS connections in new and different ways.