Implements the source PDF's prescribed model for directory structure:
'treat the CZYX cube as the only persistent store, with system calls that
operate on CZYX records and Null-space flags rather than paths and inodes.'
Nested dirs are RECONSTRUCTED from a per-record `path` metatag, so the
filesystem does not need recursive inode trees.
- cubecoords: add CubeHeader.path (Option<String>) + HAS_PATH flag bit (1<<8);
refresh_flags() sets it. Cubestore TLV codec now serializes/deserializes the
path as tag 13 (persists across checkpoint/reopen).
- cubestore: scan_by_path (exact), scan_by_path_prefix (dir listing by path
prefix; bare '/etc' normalized to '/etc/'), plus query_by_path/_prefix
returning decoded (coord,header,body).
- cubesys: `put` verb gains path=<p>;
new `query-path <dir>` verb reconstructs a directory listing from metatags.
- ConcurrentStore: query_by_path(_prefix) delegate to inner CubeStore.
Verified live in VM: migrated /etc/passwd, /etc/network/interfaces, /usr/bin/ls
at unrelated coordinates; 'query-path /etc' returns the two /etc files,
'/usr/bin/ls' correctly excluded. cubestore 8/8 tests pass.
Refs: OS-in-CUBE migration, query-layer prototype.
Integrates Packages 3-5 over a single shared CubeStore, the literal
CUBELinux premise (data addressed by coordinate, not path). Adds the
cubesys crate (lib + cube CLI + cube-demo) proving two end-to-end
properties: a cubefs path IS a runnable code cell at the same coordinate,
and a sealed record reopens and runs on the same store.
Two latent cross-crate bugs surfaced and fixed while integrating:
- cubecoords: refresh_flags() now preserves out-of-band flag bits
(8..=15), so cubecrypt's HEADER_FLAG_ENCRYPTED survives refresh.
- cubestore: record codec now serializes raw flag bits (TLV tag 12) so
the encrypted bit survives the store round-trip.
All gates green (./check, incl. cubefs --features mount).
The workspace had no single verification entrypoint, so every claim of
'green' rested on an ad-hoc command chosen after the fact. ./check makes it
one command, mirroring the convention already used by the original build.
./check fmt + tests + clippy -D warnings
./check quick tests only
./check mount the above + live FUSE end-to-end (root, 27 assertions)
The FUSE adapter compiles in every stage (--features cubefs/mount) so the
kernel-facing code can never silently rot behind a feature flag. The live
mount stage is opt-in because it needs root, /dev/fuse and attr — but it is
the only stage that exercises the real kernel VFS path, and it encodes the
two Package 3 regressions (mkdir -p to depth 4, cross-user ACLs) that every
unit test missed.
Adopting clippy -D warnings immediately paid for itself: it failed on two
pre-existing Package 1 defects that per-crate greps had let through —
a needless_range_loop in TriEnc::unpack_6 and a doc comment orphaned by a
blank line in HeaderFlags. Both fixed.
Verified: ./check green; ./check mount green (27/27, no leftover mounts).
Implements the PDF's Package 3 with new code:
- path: bijective POSIX path <-> Czyx mapping (/c001/z002/y003/x004).
Axis-letter + 3-digit zero-padded canonical names so lexical order equals
numeric order and each coordinate has exactly one spelling. Inode IS the
packed u32 coordinate — no inode side table.
- nullspace: the PDF's 'use Null cubes for ACLs, xattrs, journaling, volume
metadata', with the Z-plane allocation fixed and documented (Z=1 volume,
Z=2 ACL, Z=3 xattr, Z=4 journal ring). ACL/xattr tables are FNV
hash-bucketed with exact-match resolution inside the bucket, because 4
axes of subject cannot injectively mirror into 2 axes of Null space.
Journal is a bounded ring; wraps are detectable via a monotonic counter.
- vfs: the whole filesystem, kernel-free and unit-testable — lookup,
readdir, create/read/write/truncate/unlink, mkdir/rmdir, ACL enforcement,
xattrs, journaling, POSIX errno mapping.
- fuse (feature 'mount'): thin kernel adapter, zero TTL (the store is
writable out-of-band, so cached metadata would go stale).
- cubestore: added the PDF's 'optional scanning primitives' (keys,
scan_prefix) and the Package 2 association API (associate, linked_to)
that cubefs needs for directory listings.
Two defects were found by LIVE MOUNT testing and fixed, not by unit tests:
1. mkdir succeeded then the kernel's revalidating lookup returned ENOENT,
so 'mkdir -p' could never reach depth 4. Directories were purely
inferred from records, making an empty directory unrepresentable. Fixed
with an explicit Null-space directory marker; rmdir removes it; readdir
merges markers in. 5 regression tests added.
2. Multi-user ACL behaviour was untestable because the mount lacked
AllowOther — the kernel returned EACCES at the mountpoint before any
request reached us. Added --allow-other.
Verified: 58 unit tests pass; clippy clean; live mount exercised with cat,
echo, dd, truncate, cp, chmod, chown, getfattr/setfattr, mkdir -p, rmdir,
find, a 200-record write loop, and cross-user reads/writes as luulu.
CUBELinux-2