[magma-beef]

Summary

Bug fix to the pre-unmount trim from #143. trimFilesystem ran timeout <secs> sudo fstrim ...: the unprivileged timeout cannot signal the root-owned sudo/fstrim it spawned (EPERM), so the host budget never bounded the trim and a slow fstrim could outlive it and keep the buildkit mount busy at unmount.

- timeout ${timeoutSecs} sudo fstrim -v${minimum} -- "${mountPath}"
+ sudo timeout ${timeoutSecs} fstrim -v${minimum} -- "${mountPath}"

sudo passes timeout's exit 124 through, so the timeout outcome classification in setup_builder.ts is unchanged. Verified on a runner image: timeout 2 sudo sleep 30 leaves sudo sleep 30 running; sudo timeout 1 sleep 30 exits 124 with the child gone.

Start here: src/main.ts (trimFilesystem). dist/ is the regenerated bundle.

No behavior change in prod today: every host still sends budget 0, so the trim is skipped before this command runs.

Checks: pnpm lint, tsc --noEmit, pnpm test (64), pnpm build.

Link to Devin session: https://app.devin.ai/sessions/2e17815c306b4c3cb7af4f6bce008a66
Open in Devin Desktop: https://app.devin.ai/desktop/session/2e17815c306b4c3cb7af4f6bce008a66?variant=devin
Requested by: @magma-beef

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🟢 Devin Review found nothing to fix · View findings

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[blacksmith-staging]

Budget now stops a slow fstrim

On Ubuntu 22.04 sudo, the before command let a slow real fstrim run its full course past a 3s budget; the after command stopped it at 3s, still classified timeout, with no fstrim left and a clean unmount. On Ubuntu 24.04 sudo the before command already stopped at 3s.

_Merge-base

_{This PR 8a0a92ce}

Also checked · 2 match

Trim within budget still reports bytes
Unsupported discard still classified

_{Proof on 8a0a92ce · mocked: Sticky disk mount (/var/lib/buildkit) (unavailable), Post step trimFilesystem (dist/index.js) (unavailable) · Did Proof get it right? Yes · No}

View full Proof report

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.