userspace, since it doesn't contain any information yet. I should
still rework this more so this is just a quickie to get the read/write
style interface more up to speed with the ioctl version.
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)
committed something, issue an abort. The abort is done through
the regular op channel, e.g. failed mkdir leads to regular rmdir,
inactive and reclaim. No internal interface is planned currently
for the one file system out of a million which would implement it
to benefit from the one case in a billion where kernel resource
allocation actually does fail and out of that one case in a trillion
where internal vs. external would make a difference.
to be vaild errno values
* include string describing error in PUFFS_ERR
* get rid of union in puffs_req, it's nothing but trouble
* pass pmp to async i/o callbacks
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".
the file server inactive less over-eagerly executed and masks some
problems with the new mounting style. Effectively, it makes some
file systems such as psshfs mountable again (only without -o allops).
the kernel it has 0 references to the node in question. In other
words, this can be used to avoid inactive(), or, if the file server
does not implement inactive, prompt reclaim for removed nodes.
as we give a reference to userspace for the puffs_node for the
duration of the poll call. So reference count puffs_node separately
from the parent vnode. vref()/vrele() is not possible due to a possible
surprise visit from VOP_INACTIVE.
and other information instead of always using VDIR. To make this
possible without races, require all root node information already
in puffs_mount() and nuke puffs_start2() and the associated start
operation completely.
requested/inspired by Tobias Nygren
for nodes upon return from the userspace. Currently it can be used
to indicate that the file server should be notified of "inactive"
in case the file server has opted to not receive inactive every
time the reference count for a vnode drops to zero. (inactive is
a common event, almost never requires any action and must be executed
sychronously, so it is wasteful).
While doing this, cleanup the release-relock nonsense from the
vntouser*() arguments. It was never enabled and the whole LOCKEDVP()
concept was very broken to begin with.
bunch of bugs.
* park structures are now always allocated from a pool instead of a
mixed stack/malloc allocation
* get rid of the whole adjbuf concept, always just alloc the maximal
amount of memory to satisfy a request
* little regression: don't allow interrupting wait from file system
to userspace; this had problems already before, but now the problems
really started to shine through. I'll try to make this work again
some day.
* fix bmap to return a sensible value in runp
kernel and flush it out all at once instead of continuous updating
* add support for delivering notifications to the file server about
when a page was written to (but disabled by default for now). the
file server can use this to request flushing or invalidating the
kernel page cache
servers. This is still pretty much on the level "if it breaks ...".
It should work for single-threaded servers which handle one operation
from start to finish in one go. Also, it does not yet totally
correctly synchronize metadata and data in some cases. So needless
to say, it needs improvement, but it is possible that will have to
wait for some lock revampage.
kernel caching. Currently supported are only flushing the name
cache for a directory or flushing the name cache for the entire fs.
Also, get rid of PNODE_INACTIVE status, since it was racy and
essentially didn't work. All this on top of being useless in the
first place ....
