fix(ext4): fail fast if mkfs.ext4 is too old for our feature set

[ValentaTomas]

Probe mkfs.ext4 -V once on first Make() and refuse to build a rootfs if the host's e2fsprogs is older than 1.43 (the first release that supports inline_data and packed_meta_blocks).

Addresses the build-break risk flagged on #2563: replaces an opaque mkfs failure with a clear, actionable error pointing at the host's e2fsprogs version. All currently-supported orchestrator hosts (Ubuntu 24.04 packer image ships 1.47.0) are well past the threshold, so this is a safety net rather than an active gate.

[cursor]

PR Summary

Medium Risk
Moderate risk because it introduces a new runtime gate in rootfs creation that can block builds if mkfs.ext4 -V output differs or version parsing fails. It also adds a dependency on sync.OnceValue availability in the project’s Go version.

Overview
This change can incorrectly fail rootfs builds if mkfs.ext4 -V output format doesn’t match the hardcoded mke2fs (\d+)\.(\d+) regex or if Atoi silently fails (errors are ignored), causing a false “too old” result. It also relies on sync.OnceValue, which will break compilation if the repo’s Go version doesn’t include it.

^{Reviewed by Cursor Bugbot for commit 410f3b8. Bugbot is set up for automated code reviews on this repo. Configure here.}

[codecov]

❌ 5 Tests Failed:

Tests completed	Failed	Passed	Skipped
2355	5	2350	5

View the full list of 5 ❄️ flaky test(s)

github.com/e2b-dev/infra/tests/integration/internal/tests/api/metrics::TestTeamMetrics

Flake rate in main: 55.56% (Passed 4 times, Failed 5 times)

Stack Traces | 3.29s run time

=== RUN   TestTeamMetrics
=== PAUSE TestTeamMetrics
=== CONT  TestTeamMetrics
    team_metrics_test.go:61: 
        	Error Trace:	.../api/metrics/team_metrics_test.go:61
        	Error:      	Should be true
        	Test:       	TestTeamMetrics
        	Messages:   	MaxConcurrentSandboxes should be >= 0
--- FAIL: TestTeamMetrics (3.29s)

github.com/e2b-dev/infra/tests/integration/internal/tests/api/sandboxes::TestUpdateNetworkConfig

Flake rate in main: 57.14% (Passed 6 times, Failed 8 times)

Stack Traces | 24.6s run time

=== RUN   TestUpdateNetworkConfig
=== PAUSE TestUpdateNetworkConfig
=== CONT  TestUpdateNetworkConfig
--- FAIL: TestUpdateNetworkConfig (24.59s)

github.com/e2b-dev/infra/tests/integration/internal/tests/api/sandboxes::TestUpdateNetworkConfig/pause_resume_preserves_allow_internet_access_false

Flake rate in main: 50.00% (Passed 6 times, Failed 6 times)

Stack Traces | 1.07s run time

=== RUN   TestUpdateNetworkConfig/pause_resume_preserves_allow_internet_access_false
Executing command curl in sandbox ij2n1b600tcpqtbc60wkt
    sandbox_network_update_test.go:372: Command [curl] output: event:{start:{pid:1365}}
    sandbox_network_update_test.go:372: Command [curl] output: event:{end:{exit_code:35 exited:true status:"exit status 35" error:"exit status 35"}}
Executing command curl in sandbox ij2n1b600tcpqtbc60wkt
    sandbox_network_update_test.go:372: Command [curl] output: event:{start:{pid:1366}}
    sandbox_network_update_test.go:372: Command [curl] output: event:{end:{exit_code:35 exited:true status:"exit status 35" error:"exit status 35"}}
    sandbox_network_update_test.go:391: Command [curl] output: event:{start:{pid:1367}}
    sandbox_network_update_test.go:391: Command [curl] output: event:{data:{stdout:"HTTP/2 302 \r\nx-content-type-options: nosniff\r\nlocation: https://dns.google/\r\ndate: Tue, 05 May 2026 01:41:21 GMT\r\ncontent-type: text/html; charset=UTF-8\r\nserver: HTTP server (unknown)\r\ncontent-length: 216\r\nx-xss-protection: 0\r\nx-frame-options: SAMEORIGIN\r\nalt-svc: h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000\r\n\r\n"}}
    sandbox_network_update_test.go:391: Command [curl] output: event:{end:{exited:true status:"exit status 0"}}
    sandbox_network_update_test.go:391: Command [curl] completed successfully in sandbox ij2n1b600tcpqtbc60wkt
    sandbox_network_update_test.go:391: 
        	Error Trace:	.../api/sandboxes/sandbox_network_out_test.go:74
        	            				.../api/sandboxes/sandbox_network_update_test.go:60
        	            				.../api/sandboxes/sandbox_network_update_test.go:391
        	Error:      	An error is expected but got nil.
        	Test:       	TestUpdateNetworkConfig/pause_resume_preserves_allow_internet_access_false
        	Messages:   	https://8.8.8.8 should be blocked
--- FAIL: TestUpdateNetworkConfig/pause_resume_preserves_allow_internet_access_false (1.07s)

github.com/e2b-dev/infra/tests/integration/internal/tests/orchestrator::TestSandboxFilesystemPauseResumeIntegrity

Flake rate in main: 50.00% (Passed 1 times, Failed 1 times)

Stack Traces | 0s run time

=== RUN   TestSandboxFilesystemPauseResumeIntegrity
=== PAUSE TestSandboxFilesystemPauseResumeIntegrity
=== CONT  TestSandboxFilesystemPauseResumeIntegrity
--- FAIL: TestSandboxFilesystemPauseResumeIntegrity (0.00s)

github.com/e2b-dev/infra/tests/integration/internal/tests/orchestrator::TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause

Flake rate in main: 50.00% (Passed 1 times, Failed 1 times)

Stack Traces | 2.98s run time

=== RUN   TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause
=== PAUSE TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause
=== CONT  TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause
Executing command bash in sandbox i29uszolytf1ea9i5k1ox (user: root)
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{start:{pid:1260}}
Executing command bash in sandbox ibdv9xwaz4u3zdmkg14pf (user: root)
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{end:{exited:true status:"exit status 0"}}
    filesystem_pause_resume_integrity_test.go:43: Command [bash] completed successfully in sandbox iva1gmblgqgsr7v4k88bl
Executing command bash in sandbox i29uszolytf1ea9i5k1ox (user: root)
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{start:{pid:1265}}
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{data:{stdout:"68733113af49d9f3d9c4f7360642109bb8ffd6ffbcaf1bc79b4ad27f6a0eb629\n"}}
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{end:{exited:true status:"exit status 0"}}
    filesystem_pause_resume_integrity_test.go:43: Command [bash] completed successfully in sandbox iva1gmblgqgsr7v4k88bl
Executing command bash in sandbox iva1gmblgqgsr7v4k88bl (user: root)
    filesystem_pause_resume_integrity_test.go:43: Command [bash] output: event:{start:{pid:1271}}
    filesystem_pause_resume_integrity_test.go:43: 
        	Error Trace:	.../tests/orchestrator/filesystem_pause_resume_integrity_test.go:114
        	            				.../tests/orchestrator/filesystem_pause_resume_integrity_test.go:133
        	            				.../tests/orchestrator/filesystem_pause_resume_integrity_test.go:43
        	Error:      	Received unexpected error:
        	            	failed to execute command bash in sandbox iva1gmblgqgsr7v4k88bl: invalid_argument: protocol error: incomplete envelope: unexpected EOF
        	Test:       	TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause
--- FAIL: TestSandboxFilesystemPauseResumeIntegrity/scattered_write_hash_survives_pause (2.98s)

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[gemini-code-assist]

Code Review

This pull request introduces a version check for the host's mkfs.ext4 utility to ensure it supports the inline_data and packed_meta_blocks features. I have no feedback to provide.