Implements the full design from the prior commit in one pass. resolve_lbn()
is the single choke point threaded through the ten public LBN-consuming
entry points (blk_get_buffer, blk_update, blk_flush, blk_is_allocated,
blk_mark_allocated, blk_mark_free, blk_is_valid, blk_get_meta, blk_set_meta,
plus blk_get_empty_buffer covered via delegation) -- an LBN->LBN redirect,
not a new storage allocator, since the LBN space is already unified across
every attached blkio_dev backend. VM window cache staleness across a
relocation reuses the existing blk_vm_check_epoch() mechanism from
Milestone 2h's hot-detach fix for free -- g.epoch bumps on relocation too.
Persistence lands in the same pass: two new uint32_t fields
(reloc_start/reloc_devblocks) appended after hdr_crc in blk_volume_meta_t,
carved from existing padding without moving any earlier field's byte
offset -- an old formatted volume's zeroed padding reads back as
reloc_devblocks=0 ("no reloc capacity"), gracefully, not a format-breaking
change. compute_totals_from_B() generalized to account for the new
reserved region. reloc_flush_to_disk()/reloc_load_from_disk() mirror the
BAM I/O functions' own absolute-devblock-addressing shape; the persisted
copy's owner is first_disk_slot() (already existed, already used for this
exact "which device is canonical" question by blk_get_volume_meta()).
blk_subsys_relocate_block() is a mechanical primitive only -- copies
content (staged through a local buffer, since obtaining the target's
blk_get_buffer() result can evict and invalidate the source's cache
pointer if they share a device), frees the source BAM entry, appends the
exception entry, bumps the epoch, flushes to disk. RELOCATE-BLOCK exposes
it to FORTH, no policy of its own (ACL's job, per this session's direction).
A first live-test attempt gave a false negative against disk/artemis.img
(predates reloc capacity, so relocation only ever existed in memory that
boot) -- traced to the test's own setup before being mistaken for a bug,
then re-verified correctly against a fresh volume (new fixture,
disk/artemis-reloc-test.img): relocated a RAMDRIVE block to the fresh
disk, confirmed live resolution through the redirect, then confirmed both
the redirect and the relocated content survived an abrupt QEMU kill and
full reboot. Also fixed three lingering "glibc" doc-comment
misattributions from Milestone 2h (the actual allocator is this kernel's
own kmalloc) that survived an earlier FABRIC-2.md-only correction. All
three architectures re-verified clean.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CXjAPTEKrgY2Mrk25KoLDn
blk_subsys_detach_device() (block_subsystem.c) walks the device chain,
refuses removal of anything but the current tail (a mid-chain removal
would corrupt every later slot's start_lbn -- this architecture's own doc
already argues USB stays last specifically to avoid that), unlinks,
shrinks total_user_lbn, closes and frees the slot. Discards rather than
flushes dirty state -- the device is physically gone by the time this
runs (PORTSC disconnect only). Trigger wiring mirrors the attach path:
bot_msc_attached (set only once attach actually succeeds) gates a new
bot_msc_detach_pending flag set at PORTSC disconnect (not Disable Slot
completion, which is conditionally skipped and would miss concurrent
connect/disconnect pairs), consumed in sk_repl_idle().
Advisor flagged the real hazard ahead of time: block_words.c's VM block
window (blk_vm_lbn[]/blk_vm_cbuf[]) can go stale across a detach then a
same-LBN re-attach, and suggested a pointer-identity re-check in
blk_vm_load() as a minimal fix. That fix was implemented, then directly
falsified by its own designed-for-this test: attach a blank device, read
a block (populating the cache), detach, re-attach a device with distinct
content at the identical LBN, read again -- served stale content from
the first device. Root cause, confirmed live: glibc's allocator hands
free(slot) straight back to the very next same-size calloc(), so the
"fresh" and stale pointers were bitwise identical despite being two
different devices. Fixed properly with a monotonic blk_subsys_epoch()
counter (bumped on every attach/detach) checked by a new
blk_vm_check_epoch() helper at the one choke point (blk_vm_find(), plus
blk_vm_flush_all() which reads the same arrays directly) that covers
every path touching the window cache -- unfooled by address reuse.
Verified live with a new disk/usb-thumbdrive-test2.img fixture (distinct
content from the existing blank test image): attach A, read (cache hit
populated), detach, re-attach B at the same LBN, read again -- correctly
ran a fresh device read and returned B's real content, not A's stale
cached zeros. The failing pointer-comparison attempt's own capture log
kept as evidence, not deleted. All three architectures re-verified clean.
FABRIC-2.md Section X 2h marked complete -- enumeration through
hot-detach all live and verified; only WRITE(10) (2g's own still-open
item) remains unimplemented in the driver, not blocking anything here.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CXjAPTEKrgY2Mrk25KoLDn
The generic block subsystem (blk_format_or_load_disk) auto-reformatted
any disk lacking its own low-level 'STFR' header at attach time, before
Artemis's Forth-level BLANK/LithosAnanke/Unrecognized classification
ever ran -- so ART-HALT-UNRECOG's "Disk preserved" message was false.
Split detection from commit: an unrecognized/blank disk is now left
PROVISIONAL (geometry computed in memory only, all writes refused)
until explicitly confirmed via the new blk_subsys_confirm_format() /
BLK-CONFIRM-FORMAT primitive. Artemis calls it from ART-FORMAT and
ART-RESUME, never from ART-HALT-UNRECOG.
Verified on amd64/aarch64/riscv64: parity intact (identical dict_hash),
normal recognized-disk resume + persist-read unaffected, and a
regenerated disk/artemis-unrecognized-test.img (the old copy had itself
been silently corrupted by this exact bug) now stays byte-for-byte
identical across a halted boot on amd64 and riscv64.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
