Files
danos/library/kernel
Daniel Samson bf9f8560c6 fat/harness: filesystems coexist without the shared vfs name; two-volume proof (S3)
A second usb-storage device (a generated data volume, serial da7a0001,
an empty FAT with no /system) plugged in beside the boot volume: the
volume manager adopts both devices and spawns a confined fat per volume,
each mounted at its own content id-path.

The test surfaced a real coexistence bug. Every filesystem bound the
single "vfs" contract name under /protocol; the second volume's fat lost
the race, service.run refused-and-exited on the held name, and that
volume never mounted. Clients don't reach filesystems by that name —
fs_resolve routes a path to its backing endpoint through the kernel
mount table by prefix — and nothing consumes "vfs", so the fix is to
bind no shared name: the harness's service_name now defaults to null.
This is the "this fades" the harness comment anticipated for the
volume-manager era; a filesystem's endpoint still serves as its mount
backend without a name.

fat logs "is a data volume" for the non-system branch so the test can
positively assert content-based detection. make-fat-image gains
--serial/--label (default unchanged) so a second image gets a distinct
id-path; the data image is generated per run, never committed. The case
fails against the pre-fix harness (the data volume's fat exits on the
refused bind) — toggle-demonstrated.

Full suite 129/129 (128 + two-volumes); the single-volume path is
unaffected by dropping the vestigial name bind.
2026-08-10 02:10:06 +01:00
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