Re: file metadata via fs API (was: [GIT PULL] Filesystem Information)

On Wed, Aug 12, 2020 at 12:14 PM Karel Zak [off-list ref] wrote:

For example,  by fsinfo(FSINFO_ATTR_MOUNT_TOPOLOGY) you get all
mountpoint propagation setting and relations by one syscall,

That's just an arbitrary grouping of attributes.

You said yourself, that what's really needed is e.g. consistent
snapshot of a complete mount tree topology.  And to get the complete
topology FSINFO_ATTR_MOUNT_TOPOLOGY and FSINFO_ATTR_MOUNT_CHILDREN are
needed for *each* individual mount.  The topology can obviously change
between those calls.

So there's no fundamental difference between getting individual
attributes or getting attribute groups in this respect.

It would be also nice to avoid some strings formatting and separators
like we use in the current mountinfo.

I think quoting non-printable is okay.

I can imagine multiple values separated by binary header (like we already
have for watch_notification, inotify, etc):

Adding a few generic binary interfaces is okay.   Adding many
specialized binary interfaces is a PITA.

Thanks,
Miklos