exists is bogus. The goal here is to produce a synthetic link count
which won't confuse fts and similar routines which "know" that
directories with a link count of 2 don't have subdirectories (and
thus, they can avoid having to stat every entry in the directory
looking for subdirectories which aren't there).
We know that non-UNIX filesystem implementations may return a link
count of `1' for directories with an indeterminate number of
subdirectories; if either the upper or lower layer returns a link
count of `1', return a link count of 1. If both layers return a link
count of 2, return a link count of 2; otherwise, return the sum of the
link count of both layers.
Also, fix PR7430: unionfs ignores read-only mounts. Check for
MNT_RDONLY in union_lookup (more-or-less as in layer_lookup) as well
as union_access() and union_setattr().
Note that a read-only union layer may still cause side effects on the
underlying filesystems... Most notably, we'll still attempt to create
shadow directories in the upper layer. Also, of course, we'll
side-effect atimes in the lower layer.
getnewvnode now checks this bit, and it if's set makes sure a vnode's not
locked before removing it from the free list.
Closes PR 7954 by Alan Barrett <apb@iafrica.com>.
Update coda to new struct lock in struct vnode.
make fdescfs, kernfs, portalfs, and procfs actually lock their vnodes.
It's not that hard.
Make unionfs set v_vnlock = NULL so any overlayed fs will call its
VOP_LOCK.
to pass down a locked node. Modify union_copyup() to call VOP_CLOSE
locked nodes.
Also fix a bug in union_copyup() where a lock on the lower vnode would
only be released if VOP_OPEN didn't fail.
UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.
this is the rest of the MI portion changes.
this will be KNF'd shortly. :-)
sommerfeld