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VOP_STAT: Provide a default value for va_gen
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Authored by markj on May 3 2021, 1:33 PM.

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Summary

Some filesystems, e.g., pseudofs and the NFSv3 client, do not provide
one.

Reported by: KMSAN

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rG FreeBSD src repository
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markj requested review of this revision.May 3 2021, 1:33 PM
sys/kern/vfs_default.c
1502

I believe that it is better to initialize the field with VNOVAL AKA -1.

For instance, UFS *set*attr compares va_gen with VNOVAL.

sys/kern/vfs_default.c
1502

I note that quite a few filesystems individually initialize va_gen as 0 in their getattr implementations. Should they be left alone?

kib added inline comments.
sys/kern/vfs_default.c
1502

Hm, UFS interprets 0 as not having i_gen initialized, not VNOVAL. See ffs_vfsops.c:ffs_vgetf().

So now I think that my suggestion is wrong, and VNOVAL is the valid value for va_gen e.g. from UFS.

This revision is now accepted and ready to land.May 3 2021, 3:14 PM
This revision was automatically updated to reflect the committed changes.