df(windows): fix Avail/Use% by using number_of_free_clusters for bavail by naoNao89 · Pull Request #9470 · uutils/coreutils

naoNao89 · 2025-11-24T06:08:00Z

Fix Windows df incorrectly reporting 0 bytes available and 100% usage for all filesystems. The issue was caused by hardcoding bavail (blocks available to non-privileged processes) to 0 instead of using the actual free clusters from Windows API.

On Windows, all mounted filesystems displayed:

Avail: 0 bytes (always)
Use%: 100% (always)
--total flag: Completely broken aggregation

This made df output useless for Windows users.

Before (Broken)

Filesystem               Size  Used Avail Use%
\Device\HarddiskVolume2  256G  180G     0 100%
\Device\HarddiskVolume3  677G  494G     0 100%
\Device\HarddiskVolume4  1.9T  1.8T     0 100%
\Device\HarddiskVolume1   50M   35M     0 100%
\Device\HarddiskVolume8   11T  5.9T     0 100%

After (Fixed)

Filesystem               Size  Used Avail Use%
\Device\HarddiskVolume2  256G  180G  76G  70%
\Device\HarddiskVolume3  677G  494G 183G  73%
\Device\HarddiskVolume4  1.9T  1.8T 100G  95%
\Device\HarddiskVolume1   50M   35M  15M  70%
\Device\HarddiskVolume8   11T  5.9T 5.1T  54%

Windows API Context

The fix correctly implements POSIX semantics on Windows:

POSIX	Windows	Meaning
`f_bfree`	`lpNumberOfFreeClusters` (no quota consideration)	Total free clusters
`f_bavail`	`lpNumberOfFreeClusters` (quota-aware)	Free clusters available to user

Windows GetDiskFreeSpaceW() already respects disk quotas, making this fix semantically correct.

Fixes

Closes #7461

Related Issues

test_file_column_width_if_filename_contains_unicode_chars started to fail recently #5015: df tests failing on Windows (tests were disabled) - can now be re-enabled
df: Fix overflow error on WSL. Default to 0 when the values are non-sense. #5381: df overflow error on WSL (fixed) - works better with correct bavail

github-actions · 2025-11-24T06:24:17Z

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

sylvestre · 2025-11-25T17:57:52Z

could you please add a test to make sure we don't regress in the future? thanks

naoNao89 · 2025-11-25T23:28:28Z

done assert!(fs_usage.bavail >= 0);

github-actions · 2025-11-25T23:43:59Z

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)

sylvestre · 2025-11-26T22:19:28Z

@naoNao89 i was thinking about tests/by-util/test_df.rs

codspeed-hq · 2025-11-27T00:03:59Z

Merging this PR will not alter performance

✅ 288 untouched benchmarks
⏩ 38 skipped benchmarks¹

_{Comparing naoNao89:fix/df-windows-bavail (2fef881) with main (d13a2e0)}

38 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 · 2025-11-27T00:06:03Z

GNU testsuite comparison:

Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

github-actions · 2025-11-27T00:54:17Z

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

github-actions · 2026-02-11T12:17:01Z

GNU testsuite comparison:

Congrats! The gnu test tests/pr/bounded-memory is no longer failing!

github-actions · 2026-02-15T02:55:46Z

GNU testsuite comparison:

GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/rm/isatty. tests/rm/isatty is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/cut/bounded-memory is now being skipped but was previously passing.
Note: The gnu test tests/unexpand/bounded-memory is now being skipped but was previously passing.
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

github-actions · 2026-02-15T03:53:24Z

GNU testsuite comparison:

GNU test failed: tests/df/skip-rootfs. tests/df/skip-rootfs is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t34. tests/factor/t34 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/rm/isatty. tests/rm/isatty is passing on 'main'. Maybe you have to rebase?
Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/rm/many-dir-entries-vs-OOM is now being skipped but was previously passing.
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

github-actions · 2026-02-15T04:28:17Z

GNU testsuite comparison:

GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t34. tests/factor/t34 is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

github-actions · 2026-02-15T05:38:48Z

GNU testsuite comparison:

GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/factor/t32 is no longer failing!
Note: The gnu test tests/cut/bounded-memory is now being skipped but was previously passing.
Note: The gnu test tests/tail/pipe-f is now being skipped but was previously passing.
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

github-actions · 2026-02-15T06:51:40Z

GNU testsuite comparison:

GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/timeout/timeout-group. tests/timeout/timeout-group is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

github-actions · 2026-02-15T08:39:43Z

GNU testsuite comparison:

GNU test failed: tests/factor/t10. tests/factor/t10 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t33. tests/factor/t33 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/factor/t34. tests/factor/t34 is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/seq/seq-epipe is now being skipped but was previously passing.
Congrats! The gnu test tests/basenc/bounded-memory is now passing!

sylvestre · 2026-02-15T09:38:54Z

tests/by-util/test_df.rs

+        "At least one filesystem should have non-zero available space. Got output:\n{}",
+        output


Suggested change

"At least one filesystem should have non-zero available space. Got output:\n{}",

output

"At least one filesystem should have non-zero available space. Got output:\n{output}"

Fix Windows df incorrectly reporting 0 bytes available and 100% usage for all filesystems. The issue was caused by hardcoding bavail (blocks available to non-privileged processes) to 0 instead of using the actual free clusters from Windows API. Changes: - Set bavail to number_of_free_clusters on Windows (was: 0) - Add regression test test_windows_avail_column_not_zero Fixes uutils#7461

github-actions · 2026-02-15T13:27:45Z

GNU testsuite comparison:

Note: The gnu test tests/tail/pipe-f is now being skipped but was previously passing.
Congrats! The gnu test tests/env/env-signal-handler is now passing!

naoNao89 force-pushed the fix/df-windows-bavail branch from 9d81e88 to 57198e8 Compare November 25, 2025 23:27

naoNao89 force-pushed the fix/df-windows-bavail branch 2 times, most recently from a388c9a to 94dd012 Compare November 26, 2025 23:50

naoNao89 force-pushed the fix/df-windows-bavail branch from 94dd012 to 586f6b7 Compare November 27, 2025 00:39

naoNao89 force-pushed the fix/df-windows-bavail branch from 4df2522 to 0f996bb Compare February 15, 2026 04:13

naoNao89 force-pushed the fix/df-windows-bavail branch from 0f996bb to 8e04006 Compare February 15, 2026 05:24

naoNao89 force-pushed the fix/df-windows-bavail branch 4 times, most recently from d8a882b to 37f3d7a Compare February 15, 2026 06:35

naoNao89 force-pushed the fix/df-windows-bavail branch 2 times, most recently from 0316c4d to e41963a Compare February 15, 2026 08:25

sylvestre reviewed Feb 15, 2026

View reviewed changes

naoNao89 force-pushed the fix/df-windows-bavail branch from e41963a to 2fef881 Compare February 15, 2026 13:19

		"At least one filesystem should have non-zero available space. Got output:\n{}",
		output

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naoNao89 commented Nov 24, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Before (Broken)

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Windows API Context

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Merging this PR will not alter performance

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naoNao89 commented Nov 24, 2025 •

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