[PR #420] [MERGED] fix(storage): recognize ZFile layers during sparse-upper detection #422

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opened 2026-10-29 14:23:13 +00:00 by bsakaguchi · 0 comments

bsakaguchi commented

2026-10-29 14:23:13 +00:00

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📋 Pull Request Information

Original PR: https://github.com/kvcache-ai/AgentENV/pull/420
Author: @guozy18
Created: 10/22/2026
Status: ✅ Merged
Merged: 10/23/2026
Merged by: @yingdi-shan

Base: main ← Head: sync/zfile-layer-detection

📝 Commits (1)

75611af fix(storage): avoid spurious ZFile and disk size warnings

📊 Changes

2 files changed (+31 additions, -14 deletions)

View changed files

📝 storage/overlaybd/src/compression/zfile.rs (+9 -5)
📝 storage/overlaybd/src/layer/layer_metadata.rs (+22 -9)

📄 Description

What

Recognize a valid ZFile header before parsing an OverlayBD LSMT header when deciding whether a layer is a sparse writable upper.

Why

Compressed layers can be smaller than an LSMT header. Reading a full LSMT header first incorrectly rejects those valid layers or emits misleading diagnostics.

N/A — focused correction of existing behavior.

Scope and non-goals

The existing ZFile header verifier and the sparse-upper detection helper.

Design and behavior changes

Share the existing ZFile header validation, read at most one LSMT header, and return false for a valid compressed layer. Raw LSMT layers keep their header validation and sparse flag checks; truncated or invalid inputs still fail.

Compatibility and operations

No API, configuration or storage-format changes. Existing compressed layers become readable by the detector. Ordinary code upgrade/revert; no data migration or new host requirements.

Validation

This branch is based directly on upstream main a97473b and contains one feature commit with no unmerged PR dependencies.

PASS: make fmt
PASS: cargo clippy --locked -p agentenv -p overlaybd -p uvm-ublk-daemon --all-targets --all-features -- -D warnings
PASS: cargo test --locked -p overlaybd --lib compression::zfile::tests (12 tests)
PASS: cargo test --locked -p uvm-ublk-daemon --lib (49 tests)
PASS: temporary reproducer fails with the old detector and passes with this fix
PASS: sparse writable upper recognition and truncated-input rejection in the same probe
PASS: git diff --check

Rust checks ran on Linux as a non-root user. The temporary reproducer was removed and is not part of the commit. Full KVM/OSS E2E was not run.

Risks and reviewer notes

The two OverlayBD file patches are preserved from the original commit. Its ublk warning-to-debug hunk is inapplicable because upstream rejects disallowed shrinking instead of warning; that rejection remains intact. Original author guozhengyan maps to guozy18, so no duplicate self-co-author trailer was added.

Checklist

One coherent change with no unrelated refactoring or formatting.
Original author attribution and author date are retained.
No private deployment configuration or credentials included.
Generated API files are unchanged.

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/kvcache-ai/AgentENV/pull/420 **Author:** [@guozy18](https://github.com/guozy18) **Created:** 10/22/2026 **Status:** ✅ Merged **Merged:** 10/23/2026 **Merged by:** [@yingdi-shan](https://github.com/yingdi-shan) **Base:** `main` ← **Head:** `sync/zfile-layer-detection` --- ### 📝 Commits (1) - [`75611af`](https://github.com/kvcache-ai/AgentENV/commit/75611af54270afc7df74ca0249d62db79d7c7246) fix(storage): avoid spurious ZFile and disk size warnings ### 📊 Changes **2 files changed** (+31 additions, -14 deletions) <details> <summary>View changed files</summary> 📝 `storage/overlaybd/src/compression/zfile.rs` (+9 -5) 📝 `storage/overlaybd/src/layer/layer_metadata.rs` (+22 -9) </details> ### 📄 Description ## What Recognize a valid ZFile header before parsing an OverlayBD LSMT header when deciding whether a layer is a sparse writable upper. ## Why Compressed layers can be smaller than an LSMT header. Reading a full LSMT header first incorrectly rejects those valid layers or emits misleading diagnostics. ## Related issue N/A — focused correction of existing behavior. ## Scope and non-goals The existing ZFile header verifier and the sparse-upper detection helper. ## Design and behavior changes Share the existing ZFile header validation, read at most one LSMT header, and return false for a valid compressed layer. Raw LSMT layers keep their header validation and sparse flag checks; truncated or invalid inputs still fail. ## Compatibility and operations No API, configuration or storage-format changes. Existing compressed layers become readable by the detector. Ordinary code upgrade/revert; no data migration or new host requirements. ## Validation This branch is based directly on upstream main `a97473b` and contains one feature commit with no unmerged PR dependencies. ```text PASS: make fmt PASS: cargo clippy --locked -p agentenv -p overlaybd -p uvm-ublk-daemon --all-targets --all-features -- -D warnings PASS: cargo test --locked -p overlaybd --lib compression::zfile::tests (12 tests) PASS: cargo test --locked -p uvm-ublk-daemon --lib (49 tests) PASS: temporary reproducer fails with the old detector and passes with this fix PASS: sparse writable upper recognition and truncated-input rejection in the same probe PASS: git diff --check ``` Rust checks ran on Linux as a non-root user. The temporary reproducer was removed and is not part of the commit. Full KVM/OSS E2E was not run. ## Risks and reviewer notes The two OverlayBD file patches are preserved from the original commit. Its ublk warning-to-debug hunk is inapplicable because upstream rejects disallowed shrinking instead of warning; that rejection remains intact. Original author guozhengyan maps to guozy18, so no duplicate self-co-author trailer was added. ## Checklist - [x] One coherent change with no unrelated refactoring or formatting. - [x] Original author attribution and author date are retained. - [x] No private deployment configuration or credentials included. - [x] Generated API files are unchanged. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

bsakaguchi

2026-10-29 14:23:13 +00:00