vfs: flatten vop vectors

[mjg]

Summary

This eliminates the following loop from all VOP calls:

while(vop != NULL && \
    vop->vop_spare2 == NULL && vop->vop_bypass == NULL)
        vop = vop->vop_default;

Test Plan

will ask pho

[kib]

sys/kern/vfs_default.c

149

Why do you need to 'register' this vector ?

sys/tools/vnode_if.awk

453

Do you really need this boolean ? Why not e.g. NULLify vop_default instead ? (I checked that e.g. nullfs does not use vop_default in obvious ways)

sys/ufs/ufs/ufs_vnops.c

2805

I would think that ufs vectors also do not need flattening.

[mjg]

sys/kern/vfs_default.c

149

For consistency with the rest. It's of no consequence for this one right now modulo surviving getnewvnode should somene pass it directly.

sys/tools/vnode_if.awk

453

I wanted to do it but vop_sigdefer walks the list and I did not want to interfere with that.

sys/ufs/ufs/ufs_vnops.c

2805

The current code is flattening stuff but I purposefully went for a more generic name to allow for whatever other stuff be useful to do in the future. If anything it is a little weird legally usable vector ops are not known upfront.

[mjg]

• pull up vop_bypass the same way

[mjg]

pho tesetd the change, no issues

[mjg]

https://svnweb.freebsd.org/base?view=revision&revision=355790