---
title: "vfs-journal — Mova code model"
description: "Mova code model of vfs/src/journal.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/vfs/src/journal.rs.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

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# vfs-journal

The groupant beside vfs/src/journal.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant
- **status:** partial source bound model
- **source:** [`vfs/src/journal.rs`](https://github.com/ElamurAI/mova-free/blob/main/vfs/src/journal.rs)
- **source SHA-256:** `c6c2ac019263f12f…`
- **repository folder:** [`vfs/src/journal.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/vfs/src/journal.rs.groupant)
- **repository commit:** `855da7bd4a7b`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [approximant](#approximant) |
| **ast** | partial | `syntax.json` |
| **composition** | partial | [composition](#composition) |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | executed bounded checks | [tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |
| `retention_budget` | retention_budget | partial source derived model | [retention_budget](#retention-budget) |
| `counter_conservation` | counter_conservation | partial source derived model | [counter_conservation](#counter-conservation) |
| `tsv_loss` | tsv_loss | partial source derived model | [tsv_loss](#tsv-loss) |
| `reset_projection` | reset_projection | partial source derived model | [reset_projection](#reset-projection) |

## Model text


### descriptant

#### vfs-journal

Bounded trace retention and counters.

##### Prospective epoch

2026-10-31: source reviewed before edits; prospective review retained under $MOVA_DATA/runs/octopus-wave31-vfs-2026-10-31/prospective.md. Predicted order/cost: O(path bytes) per retained record amortized, O(1) dropped record; memory O(sum retained path bytes+min(events,2cap)); TSV/summary output proportional to retained serialization.

##### Observation epoch

Bounded actual calls and compiled negative controls are recorded in tests.md. Production behavior bytes unchanged; only focused test blocks added. Snapshot constant-time wording is conditional on cwd and destruction; recursive operations may partially commit.

##### Unsupported approximants

No executable percentage surrogate is claimed for these categorical/state/effect observations. Future 1%,2%,5%,10% require a useful metric, explicit domain and exact reference.

### approximant

#### Forward relation

Bounded trace retention and counters.

record first increments seq and classified error counters; room=cap for success or saturating_mul(cap,2) for error. If len>=room drop++, else append Entry(seq,time,op,path,bytes,errno). clear resets counters while retaining cap.

Domain: bounded inputs with available allocation and nonoverflowing counters unless checked explicitly. The relation is partial and source-derived.

### composition

#### Composition

Bounded trace retention and counters. Shared state and order: record first increments seq and classified error counters; room=cap for success or saturating_mul(cap,2) for error. If len>=room drop++, else append Entry(seq,time,op,path,bytes,errno). clear resets counters while retaining cap.

Scoped children project this same source. Their domains and effects remain conditional; source execution connects these clauses rather than independently proving their wiring. Before u64 overflow, total=retained+dropped; errors/denied/limited count dropped events too. Retained seq increases but may have gaps. cap0 drops even errors.

### models

## Typed source models

Source-bound partial relations; no universal finite-test proof.

### behavior_complement

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: At full cap ordinary success cannot append; error counters cannot omit dropped errors. Error headroom is bounded and does not promise every error retained.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### reverse_reconstruction

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: Retained entries plus counters admit many dropped op/path/time traces. TSV replaces tab/newline with spaces, so original path has ambiguous fibers. clear erases all histories.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### retention_budget

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: room=cap or saturating2cap; error acceptance depends on current total retained length, not separate error quota.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### counter_conservation

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: seq=entries.len+dropped for nonoverflowing calls after clear; errors<=seq, denied<=errors, limited<=errors.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### tsv_loss

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: Path tabs and newlines map to spaces; TSV is observation-only, not a lossless event codec.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### reset_projection

Subject: vfs-journal. Domain: Bounded trace retention and counters. Valid allocations, bounded counters, Fault=None unless explicitly named. Observation: one call or the stated finite trace.

Operator: clear keeps cap but erases seq/errors/denied/limited/dropped/entries; no replay state survives.

Approximation: source-derived partial relation; complement is an inner excluded-behavior claim under these premises, converse retains compatible antecedents. Evidence: tests.md; unobserved concurrency/resource failures remain unknown.

### tests

#### Checks and limitations

Exact named observations: journal::wave31::capped_trace_and_projection, journal_records_ops_errors_and_denials.

Fresh receipts: $MOVA_DATA/runs/octopus-wave31-vfs-2026-10-31; run.sh retains four profile/repetition sets with raw logs and numeric statuses. native-commands.json and source-test-map.json disambiguate targets. Compiled mutations and exact restoration are separately retained in mutation-summary.json.

These finite observations are not semantic completeness. Source syntax generated twice and compared byte-for-byte. Host effects are limited to owned TMPDIR fixtures. Existing absolute_paths_never_reach_the_host and open_modes are skipped; snapbench main is skipped. Standalone helpers/reexports are only observed through named callers or representation checks; RealFs effect methods unexecuted.

### invariant-and-cost

## Invariant and cost

### Invariant

Before u64 overflow, total=retained+dropped; errors/denied/limited count dropped events too. Retained seq increases but may have gaps. cap0 drops even errors.

### Cost

O(path bytes) per retained record amortized, O(1) dropped record; memory O(sum retained path bytes+min(events,2cap)); TSV/summary output proportional to retained serialization.

No timing or numerical error guarantee is inferred from finite tests.