Besides the fifo ops, there are a bunch more..

ntfs/ntfs_vnops.c:933		no getpages or putpages
smbfs/smbfs_vnops.c:151		present, but commented out.
deadfs/dead_vnops.c:100		no getpages or putpages
fdesc/fdesc_vnops.c:135		no getpages or putpages
kernfs/kernfs_vnops.c:149	no getpages or putpages
nullfs/null_vnops.c	no getpages or putpages
overlay/overlay_vnops.c	no getpages or putpages
portal/portal_vnops.c	no getpages or putpages
procfs/procfs_vnops.c	no getpages or putpages
umapfs/umap_vnops.c	no getpages or putpages
union/union_vnops.c		no putpages

not sure how many of these could cause trouble in the same way as FIFO's..

				- Bill