The block driver protocol and libblockdriver's bdr_ioctl hook are
changed, as well as the users of this hook. Other parts of the system
are expected to change accordingly eventually, since the ioctl(2)
prototype has been aligned with NetBSD's.
Change-Id: Ide46245b22cfa89ed267a38088fb0ab7696eba92
I/O control requests now come with the endpoint of the user process
that initiated the ioctl(2) call. It is stored in a new BDEV_USER
field, which is an alias for BDEV_FLAGS. The contents of this field
are to be used only in highly specific situations. It should be
preserved (not replaced!) by services that forward IOCTL requests,
and may be set to NONE for service-initiated IOCTL requests.
Change-Id: I68a01b9ce43eca00e61b985a9cf87f55ba683de4
This constant determines the range of valid device_id_t values that
a block driver can return from the bdr_device hook: a value between
0 and (BLOCKDRIVER_MAX_DEVICES - 1) inclusive.
Change-Id: I80fac469e88ac13d4b869007e6f2c2f7569da433
- internal structure rearrangement;
- respond to char device open requests to avoid hanging VFS threads;
- make drivers use designated initializers;
- use devminor_t for all minor device numbers;
- change bdr_other hook to take ipc_status and return nothing;
- fix default geometry computation;
- add support for sef_cancel.
Change-Id: Ia063a136a3ddb2b78de36180feda870605753d70
. all invocations were S or D, so can safely be dropped
to prepare for the segmentless world
. still assign D to the SCP_SEG field in the message
to make previous kernels usable
This removes a race condition when the block driver performs a
complete restart after a crash (the new default). If any user of
the driver finds out its new endpoint and sends a request to the
new driver instance before this instance has had the chance to
initialize, then its initialization would clear all IPC state and
thereby erroneously cancel the incoming request. Clearing IPC
state is only desired upon a stateful restart (where the driver's
endpoint is retained). This information is now passed to and used
by libblockdriver accordingly.
Each block driver now gets to specify whether it is a disk block
driver, which implies it wants the library to handle getting and
setting partitions for it.
The implementation is in libblockdriver, and works transparently for
all block drivers. The new btrace(8) tool can be used to control block
tracing; see ``man btrace'' for details.
This patch separates the character and block driver communication
protocols. The old character protocol remains the same, but a new
block protocol is introduced. The libdriver library is replaced by
two new libraries: libchardriver and libblockdriver. Their exposed
API, and drivers that use them, have been updated accordingly.
Together, libbdev and libblockdriver now completely abstract away
the message format used by the block protocol. As the memory driver
is both a character and a block device driver, it now implements its
own message loop.
The most important semantic change made to the block protocol is that
it is no longer possible to return both partial results and an error
for a single transfer. This simplifies the interaction between the
caller and the driver, as the I/O vector no longer needs to be copied
back. Also, drivers are now no longer supposed to decide based on the
layout of the I/O vector when a transfer should be cut short. Put
simply, transfers are now supposed to either succeed completely, or
result in an error.
After this patch, the state of the various pieces is as follows:
- block protocol: stable
- libbdev API: stable for synchronous communication
- libblockdriver API: needs slight revision (the drvlib/partition API
in particular; the threading API will also change shortly)
- character protocol: needs cleanup
- libchardriver API: needs cleanup accordingly
- driver restarts: largely unsupported until endpoint changes are
reintroduced
As a side effect, this patch eliminates several bugs, hacks, and gcc
-Wall and -W warnings all over the place. It probably introduces a
few new ones, too.
Update warning: this patch changes the protocol between MFS and disk
drivers, so in order to use old/new images, the MFS from the ramdisk
must be used to mount all file systems.
