Empty QCOW images consist of only the L1 table, this results in a
file size which is not sector-aligned. Since blktap uses O_DIRECT, the
block aligned read of the L1 table will go beyond the end of file and
thus returns the actual file size and not the expected length.
This patch checks whether at least the L1 table has been read.
This should fix bug 1430.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
As pointed out in Xen Bugzilla 1430 in the blktap QCOW driver the
rounding function is wrong in line 824 of block-qcow.c.
This patch replaces this (and other roundings) with the already
existing ROUNDUP macro (and fixes the usual macro pitfall).
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Until now the udev script for blktap devices needs to decide if to
signal success or failure to xend. As this script runs completely
independent of blktapctrl and tapdisk/ioemu which do the real work,
the udev script can't even theoretically know if tapdisk is happy.
This patch removes the udev script and replaces its checks by new
ones in libblktap.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
Connections to ioemu have single_handler set, so they are closed as
soon as all images of a certain type are closed. This is wrong with
ioemu: All images that belong to the same domain are handled by the
same backend process (usually qemu-dm, but also tapdisk-ioemu for
domains without device model), regardless of the image type.
This patch checks for the same-domain condition for ioemu connections.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
Currently all disk types that are supported are defined in a header
file private to blktapctrl and tapdisk. When restoring ioemu as a
backend for blktap these constants are needed by ioemu, so move them
to a more public header file.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
This patch adds support for specifying the backend (tapdisk or ioemu)
to blktapctrl. Images can be specified e.g. as tap:tapdisk:aio,
tap:ioemu:qcow2 or tap:vmdk. When omitting the backend, a default is
chosen based on the image type (currently always tapdisk because ioemu
as a backend is broken until a follow-up patch series against qemu-xen
is applied)
Signed-off-by: Kevin Wolf <kwolf@suse.de>
This has finally bugged me enough to do something about it:
make prints `***' when it stops due to an error. With make -j, and/or
with automated build systems, this error marker can be in the middle
of a large logfile. It is useful to be able to search for it.
Therefore change occurrences of `*' to `=' for information and warning
messages. `***' is reserved for cases where the build stops.
A corresponding change is being applied to qemu-xen-unstable.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
If you use -MMD -MF then the correct .o filename is written to the
.*.d file as the compiler driver arranges everything. This was done
in 19010:275abe1c5d24 for the hypervisor.
In this patch we do the same elsewhere in the xen-unstable tree,
particularly tools/. Specifically:
* Change tools/Rules.mk to add -MMD -MF ... to CFLAGS and set DEPS.
* Remove -Wp,-MD... from every other Makefile
* Remove setting of DEPS from every other Makefile
* Ensure that every Makefile says -include $(DEPS)
* Ensure that every Makefile's clean target removes $(DEPS)
Some Makefiles were already halfway there, but often for a different
variable name eg PROG_DEP. The variable name is now standardised in
Rules.mk as DEPS.
I have done a test build with this change, on Debian etch.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Turns out that only two reads and writes in block-qcow.c need to be
fixed to work correctly with O_DIRECT.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Make functions w/o a prototype static and remove redundant
declaration of xs_fire_next_watch().
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
I originally had just changed the NEWINTF ioctl to send over 48-bits
of information, which works on 64-bit but not on 32-bit (since the arg
is an unsigned long). Additionally, the previous changes would break
an older userland against a new kernel. For that reason, introduce a
new ioctl (NEWINTF_EXT) that fixes both of these problems. This is
the dom0 userland side.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
tapdisk, part of blktap, links against libcrypto. tapdisk includes
GPLv2 (tapaio.c) and other licensed code (block-qcow.c). The license
of OpenSSL is considered incompatible with the GPL by many
people. This patch changes them to link against libgcrypt, which is
LGPL.
Signed-off-by: Bastian Blank <waldi@debian.org>
When a domain wants to use a tap:ioemu disk but has no device model,
start a tapdisk-ioemu instance as provider. Also, move the creation
and removal of communication pipes to xend so that qemu-dm doesn't
need the unwanted SIGHUP handler anymore.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
When a domain wants to use a tap:ioemu disk but has no device model,
start a tapdisk-ioemu instance as provider. Also, move the creation
and removal of communication pipes to xend so that qemu-dm doesn't
need the unwanted SIGHUP handler anymore.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
Fix tapdisk to use big endian L1 tables as used by qemu/ioemu. Old
tapdisk images with native endianess are automagically converted to
big endian when the image file is opened for the first time.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
With some combinations of compiler flags (no optimization, -Werror),
the compiler may complain that the function doesn't have a return
statement (even if the function actually just never returns), reported
as bug 1128. This adds a dummy return statement.
Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
Add support for a tap:ioemu pseudo driver. Devices using this driver
won't use tapdisk (containing the code duplication) any more, but will
connect to the qemu-dm of the domain. In this way no working
configuration should be broken right now as you can still choose to
use the tapdisk drivers.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
With my qcow2 patch to blktap I contributed a bit to the mess, so here
an attempt to clean up and remove at least some of the code
duplication in the functions dealing with aio operations.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
This patch adds support for the qcow2 image format to blktap. It
consists mostly of qemu code, adapted to the blktap interfaces.
Snapshots and compressed images are supported.
The qcow2 driver may be used by either specifying tap:qcow2 or by
using tap:qcow which will detect that you have a version 2 image and
will call the qcow2 driver.
Signed-off-by: Kevin Wolf <kwolf@suse.de>
mb/rmb/wmb. Instead add a xen_ prefix. Modify Xen's public headers to
expect the prefixed names instead of bare mb/rmb/wmb, but gate this
expectation on a bump of __XEN_INTERFACE_VERSION__.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
In tools/blktap/drivers/tapaio.c there is a call to read(2) whose
return value is not checked. The attached patch attempts to do
something vaguely sensible in cases of error.
Fully comprehensive error handling in this area would be quite tough
to introduce now but at least with this change when things go wrong
you stand a chance of getting some information about what happened.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Attached patch removes unused linux specific headers
and makes bswap.h ready for BSD support.
This is first step for BSD support in blktap. More to come.
No functional change.
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
The blktapctrl process is responsible for spawning individual tapdisk
processes. It does this using the 'system' method, but unfortunately
none of its file descriptors have the close-on-exec flag set. The
parent blktapctl process opens a couple of unix domain sockets
per-tapdisk it spawns. So the first tapdisk get 2 FDs leaked to it,
the second gets 4 FDs leaked to it, the 3rd gets 6 and so on. The use
of 'system' also unneccessarily invokes the shell.
Replace system with fork/execvp, and explicitly close all file handles
up to _SC_OPEN_MAX.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Fixes correctness issues with xenstored and gcc-4.2.
Original patch by Charles Coffing <ccoffing@novell.com>
Signed-off-by: Keir Fraser <keir@xensource.com>
blktap requires a xen specific kernel AIO ABI which has been vetoed by
upstream in favour of another approach. Rather than include this ABI,
Fedora has been carrying a patch which makes tap:aio use a thread to
poll for aio events and notify the main thread via a pipe.
The upstream approach of allowing io_getevents() poll normal file
descriptors via epoll is still progressing:
http://lkml.org/lkml/2007/1/3/16
but when that does make it upstream, blktap will require significant
re-working to use that approach.
In the meantime, here's a patch which uses the poll-in-a-thread
approach only if AIO poll support isn't available. It also hides the
details behind a simple abstraction and makes both tap:aio and
tap:qcow use it.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Note that some of the existing error checking for asprintf was wrong
for Linux. asprintf in glibc returns -1 on error, but leaves the
pointer uninitialized. Only the BSDs zero out the pointer on error.
Also, while fixing these warnings I saw several error paths that were
incorrect. This patch minimally fixes the warn_unused_result; more
complete error path cleanup will be a later patch.
Signed-off-by: Charles Coffing <ccoffing@novell.com>
Keir Fraser
kfraser@localhost.localdomain
Keir Fraser