I don't think protocol specific data really belongs in this header
but since it is already there and we seem to be stuck with it let's at
least make the users explicit lest people get caught out by future new
fields moving the pad field around.
This is the Xen portion of this change. The kernel portion will be
sent separately. There is no dependency between the two.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Daniel Stodden <daniel.stodden@citrix.com>
Cc: Dongxiao Xu <dongxiao.xu@intel.com>
Tapdisk control in userspace, a replacement for the original blktap2
control stack, which had to pass a kernel space interface based on
sysfs nodes.
All tapdisk processes listen for commands on a unix stream socket. The
control library supports scanning the socket namespace for running
tapdisks, VBD minors allocated, associated images and state inquiry.
Control operations include allocating/releasing devices, spawning
tapdisks, opening/closing images, attaching disk images to
devices. disk pause/resume operations and runtime switching of disk
images.
Signed-off-by: Jake Wires <jake.wires@citrix.com>
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Stop coercing drivers/disktype code into the tool stack. Make both
blktapctrl and tap-ctl transfer type/path pairs as "<type>:<path>"
strings. Remove the message.disktype integer altogether.
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jake Wires <jake.wires@citrix.com>
1. Some files use stat, mkfifo, mkdir etc. without including
sys/stat.h
2. Some programs link against libpthread without a -lpthread compile
option. The compile used to work if this library happened to be used
by one of the other libraries that was being linked against, but
Fedora 13 has stopped allowing this.
From: M A Young <m.a.young@durham.ac.uk>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
500ms is aggressive enough to trigger split-brain under fairly
ordinary workloads, particularly for HVM. The long-term fix is to
integrate with a real HA monitor like linux HA.
Signed-off-by: Brendan Cully <brendan@cs.ubc.ca>
Mainline kernel support for eventfd(2) in linux aio was added between
2.6.21 and 2.6.22. Libaio after 0.3.107 has the header file, but
presently few systems support it. Neither do we rely on an up-to-date
libc6.
Instead, this patch adds a header which defines custom iocb_common
struct, and works around a potentially missing sys/eventfd.h.
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Hide tapdisk support for different raw I/O interfaces behind a new
struct tio. Libaio remains to dominate the interface, requiring
everyone to dispatch iocb/ioevent structs.
Backends:
- lio: Kernel AIO via libaio.
- rwio: Canonical read/write() mode.
Misc:
- Fixes a bug in tapdisk-vbd which locks up the sync io mode.
- Wants a PERROR macro in blktaplib.h
- Removes dead code in qcow2raw to make it link again.
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jake Wires <jake.wires@citrix.com>
Move event callbacks registration into tapdisk-queue. This should also
obsoletes the dummy pollfd pipe in the synchronous I/O case.
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Attached patch makes memshr optional for blktap/blktap2.
This fixes build for platforms where memshr isn't build on.
While there, make indentation consistent.
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
detect sharable memory pages). This patch establishes unique id for each disk
image opened by tapdisk2, and stores it in shared memory region, thus making it
available to the remaining tapdisk2s.
Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>
the tapdisk2 process if sharing is enabled (tapdisk2 is not normally aware what
domain it is working for).
Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>
a single map is used to store mappings between sharing handles and disk blocks.
This is used to share pages which store data read of the same blocks on
(virtual) disk.
Note that the map is stored in a shared memory region, as it needs to be
accessed by multiple tapdisk processes. This complicates memory allocation
(malloc cannot be used), prevents poniters to be stored directly (as the shared
memory region might and is mapped at different base address) and finally pthread
locks need to be multi-process aware.
Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>
(4K) block read into 8 (512 bytes) sector reads. This is inefficient, but also
prevents sharing detector from working, as it is based on page-size reads.
Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>
If we want to check the functionality of libgcrypt, we shouldn't test
a function only exported by openssl, but instead the one actually used
in the code.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Blktap2 port of remus disk driver. Backwards compatable with blktap1
implementation.
Signed-off-by: Ryan O'Connor <rjo@cs.ubc.ca>
Signed-off-by: Brendan Cully <brendan@cs.ubc.ca>
Currently blktap2 opens a driver stack, closes it, and re-opens
it. This causes problems with our remus driver: the primary may
connect to the backup in between the first and second open.
This is a temporary fix.
Signed-off-by: Ryan O'Connor <rjo@cs.ubc.ca>
Blktap2 allows block device drivers to be layered to create more
advanced virtual block devices. However, composing a layered driver is
not exposed to the user. This patch fixes this, and allows the user to
explicitly specify a driver chain when starting a tapdisk process,
using the pipe character ('|') to explicitly seperate layers in a
blktap2 configuration string.
for example, the command:
~$ tapdisk2 -n "log:|aio:/path/to/file.img"
will create a blktap2 device where read and write requests are passed
to the 'log' driver, then forwarded to the 'aio' driver.
Signed-off-by: Ryan O'Connor <rjo@cs.ubc.ca>
- Use standard off_t and lseek() instead of non-portable off64_t and
lseek64()
- Use uuid API as documented in DCE 1.1 RPC specification
- Add NetBSD implementation for blk_getimagesize() and
blk_getsectorsize()
- Use blk_getimagesize() and blk_getsectorsize()
- Fix uuid header check
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
This patch re-enables a useful blktap1 for users who disable blktap2.
Itremoves tapdisk and blktapctrl from blktap2, both of which cause
problems with blktap operation. In addition, this patch modifies xend
to check for blktap2 installation. If the blktap2 driver isn't
running (hopefully because the dom0 kernel option wasn't selected) we
fall back to blktap.
Signed-off-by: Dutch Meyer <dmeyer@cs.ubc.ca>
is passed a struct-by-value which is not yet fully defined. Thus
defining a request struct which contains a pointer to a function which
is passed-by-value an instance of that request structure is
impossible. We work around it by defining the function poiinter as
void* and then casting in one place.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
- clean up to use SUBDIRS-y
- With parallel make, libvhd might not be created before
link. guarantee it.
- use LDFLAGS for link which is set by upper level makefiles.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Benefits to blktap2 over the old version of blktap:
* Isolation from xenstore - Blktap devices are now created directly on
the linux dom0 command line, rather than being spawned in response
to XenStore events. This is handy for debugging, makes blktap
generally easier to work with, and is a step toward a generic
user-level block device implementation that is not Xen-specific.
* Improved tapdisk infrastructure: simpler request forwarding, new
request scheduler, request merging, more efficient use of AIO.
* Improved tapdisk error handling and memory management. No
allocations on the block data path, IO retry logic to protect
guests
transient block device failures. This has been tested and is known
to work on weird environments such as NFS soft mounts.
* Pause and snapshot of live virtual disks (see xmsnap script).
* VHD support. The VHD code in this release has been rigorously
tested, and represents a very mature implementation of the VHD
image
format.
* No more duplication of mechanism with blkback. The blktap kernel
module has changed dramatically from the original blktap. Blkback
is now always used to talk to Xen guests, blktap just presents a
Linux gendisk that blkback can export. This is done while
preserving the zero-copy data path from domU to physical device.
These patches deprecate the old blktap code, which can hopefully be
removed from the tree completely at some point in the future.
Signed-off-by: Jake Wires <jake.wires@citrix.com>
Signed-off-by: Dutch Meyer <dmeyer@cs.ubc.ca>
Keir Fraser