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Ensure that d_off is initialized
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Authored by markj on Dec 28 2020, 12:39 AM.

Details

Summary

We have the d_off field in struct dirent for providing the offset of the
next directory entry. Several filesystems did not populate the field,
which ends up being leaked.

Reported by: Syed Faraz Abrar <faraz@elttam.com>

Diff Detail

Repository
R10 FreeBSD src repository
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Automatic diff as part of commit; lint not applicable.
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Automatic diff as part of commit; unit tests not applicable.

Event Timeline

This revision is now accepted and ready to land.Dec 28 2020, 8:03 PM

I don't remember much about how directory entries work, but I don't see anything wrong with the patch. I have a question, though: how did it work before? Is that field actually used?

d_off was added during ino64 work, for supposed benefit of nfs server. I believe the idea was that d_off use could replace cookies.

Right now it is not used, and d_off presence is optional. If d_off is zero, userspace has to use other methods (lseek ?) to bookmark directory position.