[LSF/MM/BPF TOPIC] finishing up mount API conversions; consistency & logging

[Eric Sandeen <sandeen@redhat.com>]

In case this is of interest to anyone I'll propose it.

The "new" mount API was merged about 5 years ago, but not all filesystems
were converted, so we still have the legacy helpers in place. There has been
a slow trickle of conversions, with a renewed interest in completing this
task.

The remaining conversions are of varying complexity (bcachefs might
be "fun!") but other questions remain around how userspace expects to use
the informational messages the API provides, what types of messages those
should be, and whether those messages should also go to the kernel dmesg.
Last I checked, userspace is not yet doing anything with those messages,
so any inconsistencies probably aren't yet apparent.

There's also the remaining task of getting the man pages completed.

There were also some recent questions and suggestions about how to handle
unknown mount options, see Miklos' FSOPEN_REJECT_UNKNOWN suggestion. [1]

I'm not sure if this warrants a full session, as it's actually quite
an old topic. If nothing else, a BOF for those interested might be
worthwhile.

Thanks,
-Eric

[1] https://lore.kernel.org/linux-fsdevel/CAJfpeguCKgMPBbD_ESD+Voxq5ChS9nGQFdYrA4+YWBz17yFADA@mail.gmail.com/