we already export mntauth() and mntversion(), so why not stop
being sneaky and just export mntattach() so bindmount() and
devshr can just call it directly with proper arguments being
checked.
we can also avoid handling #M attach specially in namec()
by having the devmnt's attach function do error(Enoattach).
make the Page stucture less than half its original size by getting rid of
the Lock and the lru.
The Lock was required to coordinate the unchaining of pages that where
both cached and on the lru freelist.
now pages have a single next pointer that is used for palloc.head
freelist xor for page cache hash chains in Image.pghash[].
cached pages are not on the freelist anymore, but will be reclaimed
from images by the pager when the freelist runs out of pages.
each Image has its own 512 hash chains for cached page lookup. That is
2MB worth of pages and there should be no collisions for most text images.
page reclaiming can be done without holding palloc.lock as the Image is
the owner of the page hash chains protected by the Image's lock.
reclaiming Image structures can be done quickly by only reclaiming pages from
inactive images, that is images which are not currently in use by segments.
the Ref structure has no Lock anymore. Only a single long that is atomically
incremented or decremnted using cmpswap().
there are various other changes as a consequence code. and lots of pikeshedding,
sorry.
if theres an error transmitting a Tclunk or Tremove request,
we cannot assume the fid to be clunked. in case this was
a transient error, reusing the fid on further requests
will fail.
as a work arround, we zero the channels fid and allocate
a new fid before the chan is reused.
this is not correct as we essentially leak the fid
on the fileserver, but we will still be able to use
the mount.
this change is in preparation for amd64. the systab calling
convention was also changed to return uintptr (as segattach
returns a pointer) and the arguments are now passed as
va_list which handles amd64 arguments properly (all arguments
are passed in 64bit quantities on the stack, tho the upper
part will not be initialized when the element is smaller
than 8 bytes).
this is partial. xalloc needs to be converted in the future.
the shr mount is linked into the Mhead with m->to initially nil. only
after the the server has been attached is m->to set. just check for
it in createdir().
closechanq() is unable to fork a new closeproc when palloc
is locked. so we spawn a closeproc early in chandevinit()
and make sure theres always one process arround to handle
the queue.
catch potential interrupt error from kproc(). this can happen when
we run out of processes, then newproc() will call rsrcwait()
which does tsleep(). if the process gets a note, this might
raise a interrupt error.
kstrcpy() did not null terminate for < 4 byte buffers. fixed,
but i dont think there is any case where this can happen in
practice.
always set malloctag in kstrdup(), cleanup.
always use ERRMAX bounded kstrcpy() to set up->errstr, q->err
and note[]->msg. paranoia.
instead of silently truncating interface name in netifinit(),
panic the kernel if interface name is too long as this case
is clearly a mistake.
panic kernel when filename is too long for addbootfile() in
devroot. this might happen if your kernel configuration is
messed up.
