interacts with the userspace file server:
* since the kernel-user communication is not purely request-response
anymore (hasn't been since 2006), try to rename some "request" to
"message". more similar mangling will take place in the future.
* completely rework how messages are allocated. previously most of
them were borrowed from the stack (originally *all* of them),
but now always allocate dynamically. this makes the structure
of the code much cleaner. also makes it possible to fix a
locking order violation. it enables plenty of future enhancements.
* start generalizing the transport interface to be independent of puffs
* move transport interface to read/write instead of ioctl. the
old one had legacy design problems, and besides, ioctl's suck.
implement a very generic version for now; this will be
worked on later hopefully some day reaching "highly optimized".
* implement libpuffs support behind existing library request
interfaces. this will change eventually (I hate those interfaces)
kernel to the file server for silly things the file server did,
e.g. attempting to create a file with size VSIZENOTSET. The file
server can handle these as it chooses, but the default action is
for it to throw its hands in the air and sing "goodbye, cruel world,
it's over, walk on by".
* in addition add/remove, allow enable/disable, which can be used
to control events for descriptors without having to remove all the
data associated with them
* add directsend/receive, which can be used to pass the same buffer
from the caller to read/writeframe and back again
* add flags to enqueue functions and allow urgent buffers to be
processed as the next PDU
and destroyed, but not yet reclaimed. This prevents puffs_pn_nodewalk()
from returning stale entries. Make nullfs use this (some file
systems are a bit too happy with recycling inode numbers).
turn a reference to puffs_framebuf in the file system from a
cb/justsend operation to a cc wait, should the file system find
itself desiring the result.
equal, larger, respectively instead of 0/1 for non/equal. This
will allow sorting the buffers for faster matching in libpuffs.
While here, change the name from respcmp to framecmp, as that better
reflects the purpose.
NOTE! there is no obvious way to make compilation fail for file
systems which may already be using this feature (although I don't
think there are any outside our tree, as the feature is two weeks
old). Nevertheless, non-updated file systems will fail very quickly.
instead of puffs_start(). Get completely rid of puffs_start(), as
everything it used to do is now handled by the mount routine.
Introduce an optional pre-mount call puffs_setrootinfo() for setting
non-default root node information. As the old puffs_mount() is
now virtually useless, say byebye to it and rename the old
puffs_domount() to puffs_mount(), but add a root cookie parameter
to compensate for the late puffs_start().
support removal and addition of i/o file descriptors on the fly.
* detect closed file descriptors
* automatically free waiters of a dead file descriptor
* give the file server the possibility to specify a callback which
notifies of a dead file descriptor
* move loop function to be a property of the mainloop instead of
framebuf (doesn't change effective behaviour)
* add the possibility to configure a timespec parameter which
attempts to call the loop function periodically
* move the event loop functions from the puffs_framebuf namespace
to puffs_framev to differential between pure memory management
functions
framebuf event loop to take n i/o fd's as parameters and also allow
dynamic add/remove of fd's. (not tested except for one fd, but more
changes coming soon)
and event handling mechanisms required in file servers with blocking
I/O backends. puffs_framebuf is built on the concept of puffs_cc
and uses those to multiplex execution where needed.
File systems are required to implement three methods:
* read frame
* write frame
* compare if frame is a response to the given one
Memory management is provided by puffs_framebuf, but the file
systems must still, of course, interpret the protocol and do e.g.
byte order conversion.
As always, puffs_framebuf is work in progress. Current users are
mount_psshfs and mount_9p.
only take the bare essentials, which currently means removing
"maxreqlen" from the argument list (all current callers I'm aware
of set it as 0 anyway). Introduce puffs_init(), which provides a
context for setting various parameters and puffs_domount(), which
can be used to mount the file system. Keep puffs_mount() as a
shortcut for the above two for simple file systems.
Bump development ABI version to 13. After all, it's Friday the 13th.
Watch out! Bad things can happen on Friday the 13th. --No carrier--
accessors for interesting data in it. Namely, you can now get
pu->pu_privdata with puffs_getspecific(), pu->pu_pn_root with
puffs_set/getroot() and pu->pu_maxreqlen with puffs_getmaxreqlen().
