dd: report transfer statistics when the copy fails

[sylvestre]

Should make test dd/partial-write.sh pass

[github-actions]

Binary size comparison:

Individual binary size comparison VS main (threshold: >=5% AND >=4 KB).

Total size of compared binaries: 148.93 MB (+316 KB, +0.21%)

Significant per-binary changes:
  install     1.24 MB ->    1.32 MB  (+80 KB, +6.29%)
  mkdir       1.09 MB ->    1.17 MB  (+80 KB, +7.14%)
  mkfifo      1.09 MB ->    1.16 MB  (+76 KB, +6.83%)
  mknod       1.09 MB ->    1.17 MB  (+76 KB, +6.79%)

[codspeed-hq]

Merging this PR will improve performance by 4.1%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 345 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	du_max_depth_balanced_tree[(6, 4, 10)]	64.6 ms	61.9 ms	+4.35%
⚡	Simulation	du_summarize_balanced_tree[(5, 4, 10)]	16.6 ms	16 ms	+3.86%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing sylvestre:dd-partial-write (10d4e38) with main (f34bc46)}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/inotify-dir-recreate (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/dd/partial-write is no longer failing!
Congrats! The gnu test tests/seq/seq-epipe is now passing!

[collinfunk]

This test is entirely copied from the referenced Coreutils test. It has become impossible to give you the benefit of the doubt at this point...

[oech3]

Does this fix #11434 too (and make a test from it with strace)?