Weird case in vfs_bio.c bwrite

[coypu%SDF.ORG@localhost]

Hi,
I've been reading the vfs code for no reason.

in vfs_bio.c:802 we have:
  vp = bp->b_vp;

then we have a test if it's NULL, but strangely, we do not leave the
function, we continue with it.

there is even a call in vfs_bio.c:873
  VOP_STRATEGY(vp, bp);
which will still happen for the vp=NULL case, if it is possible.

what is this case?

Thanks.