cp: Adjust the sparse file tests.
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Authored by des on Feb 7 2023, 1:10 PM.

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cracauer

Group Reviewers

Klara

Commits

rG8b418c83d175: cp: Adjust the sparse file tests.

Summary

The sparsity check was ineffective: it compared the apparent size in bytes to the actual size in blocks.
Some of the seq commands were missing an argument.
Based on empirical evidence, 1 MB holes are not necessarily large enough to be preserved by the underlying filesystem. Increase the hole size to 16 MB.

MFC after: 1 week
Sponsored by: Klara, Inc.

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rG FreeBSD src repository

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Buildable 49596
Build 46486: arc lint + arc unit

des created this revision.Feb 7 2023, 1:10 PM

des requested review of this revision.Feb 7 2023, 1:10 PM

LGTM

This revision is now accepted and ready to land.Feb 8 2023, 2:29 PM

markj added inline comments.

bin/cp/tests/cp_test.sh
204	Hmm, I think this is a bit too simplistic. On ZFS I see: markj@nuc> jot 4096 1 1 > 1 markj@nuc> du -h 1 512B 1 markj@nuc> du -hA 1 8.0K 1 markj@nuc> dd if=/dev/random of=2 bs=4K count=1 1+0 records in 1+0 records out 4096 bytes transferred in 0.000220 secs (18653284 bytes/sec) markj@nuc> du -h 2 4.5K 2 markj@nuc> du -hA 2 4.0K 2 Neither of these files is sparse obviously, and it looks like ZFS is reporting the size of the dnode as well as a compressed size. I can't think of a way to check for holes from the shell.

des marked an inline comment as done.Feb 8 2023, 3:55 PM

des added inline comments.

bin/cp/tests/cp_test.sh
204	That's a good point. I suppose I could write a hole detection tool in C. It's still better than the previous version (which would report every file as sparse).