size != 512 that are configured without a label. The bug should only
have effected swap-backed VN mounts without a label.
Add several major features to VN. In the kernel we add a swap
pre-reservation capability, which can be used to guarentee seek
consistency for swap-backed VN nodes. This also incidently allows
a swap-backed VN filesystem to be recovered after a crash in some
cases (if the same swap blocks happen to be reserved).
We also add a number of new options to vnconfig which do the work
of pre-zeroing or creating/truncating/extending a file which greatly
simplifies using VN in a file-backed configuration.
Add FreeBSD CVS label to sys/sys/vnioctl.h, as well as a new ioctl
flag for the swap pre-reservation feature.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
The old VN device broke in -4.x when the definition of B_PAGING
changed. This patch fixes this plus implements additional capabilities.
The new VN device can be backed by a file ( as per normal ), or it can
be directly backed by swap.
Due to dependencies in VM include files (on opt_xxx options) the new
vn device cannot be a module yet. This will be fixed in a later commit.
This commit delimitted by tags {PRE,POST}_MATT_VNDEV
vnconfig doesn't seem to be in Lite2, although dev/vn is. The Lite2
merge in userland has converted all mount calls except this one and
one for devfs in init, so we can drop support for old mount args soon.
Vnconfig probably shouldn't support mounting - it only supports ufs.
