Right now, nbd_wr_sync will hang if no data at all is available on the
socket and the other side is not going to provide any. Relax this by
making it loop only for writes or partial reads. This fixes a race
where one thread is executing qemu_aio_wait() and another is executing
main_loop_wait(). Then, the select() call in main_loop_wait() can return
stale data and call the "readable" callback with no data in the socket.
Reported-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the next patch we need to look at the return code of nbd_wr_sync.
To avoid percolating the socket_error() ugliness all around, let's
handle errors by returning negative errno values.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
GCC (pedantically, but correctly) considers that a negative ssize_t may
become positive when casted to int. This may cause uninitialized variable
warnings when a function returns such a negative ssize_t and is inlined.
Propagate ssize_t return types to avoid this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Limiting the number of in-flight requests is implemented very simply
with a can_read callback. It does not require a semaphore, unlike the
client side in block/nbd.c, because we can throttle directly the creation
of coroutines. The client side can have a coroutine created at any time
when an I/O request is made.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Using coroutines enable asynchronous operation on both the network and
the block side. Network can be owned by two coroutines at the same time,
one writing and one reading. On the send side, mutual exclusion is
guaranteed by a CoMutex. On the receive side, mutual exclusion is
guaranteed because new coroutines immediately start receiving data,
and no new coroutines are created as long as the previous one is receiving.
Between receive and send, qemu-nbd can have an arbitrary number of
in-flight block transfers. Throttling is implemented by the next
patch.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
By attaching a client to an NBDRequest, we can avoid passing around the
socket descriptor and data buffer.
Also, we can now manage the reference count for the client in
nbd_request_get/put request instead of having to do it ourselved in
nbd_read. This simplifies things when coroutines are used.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch sets up the fd handler in nbd.c instead of qemu-nbd.c. It
introduces NBDClient, which wraps the arguments to nbd_trip in a single
structure, so that we can add a notifier to it. This way, qemu-nbd can
know about disconnections.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the buffer from NBDExport to a new structure, so that it will be
possible to have multiple in-flight requests for the same export
(and for the same client too---we get that for free).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Group the sending of a reply and the associated data into a new function.
Without corking, the caller would be forced to leave 12 free bytes at the
beginning of the data pointer. Not too ugly, but still ugly. :)
Using nbd_do_send_reply everywhere will help when the routine will set up
the write handler that re-enters the send coroutine.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use TCP_CORK to remove a violation of encapsulation, that would later
require nbd_trip to know too much about an NBD reply.
We could also switch to sendmsg (qemu_co_sendv) later, it is even
easier once coroutines are in.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update ioctl(s) in nbd_init() to detect device busy early.
Current nbd_init() issues NBD_CLEAR_SOCKET before NBD_SET_SOCKET, if issuing
"qemu-nbd -c /dev/nbd0 disk.img" twice, the second time won't detect EBUSY in
nbd_init(), but in nbd_client will report EBUSY and do clear socket (the 1st
time command will be affacted too because of no socket any more.)
No change to previous version.
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This can be seen with "qemu-nbd -v -c", which returns 1 instead of 0
when you disconnect with "qemu-nbd -d".
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The nbd kernel module cannot enable DISCARD requests unless it is
informed about it. The flags field in the header is used for this,
and this patch adds support for it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
nbd supports writing flags in bytes 24...27 of the header,
and uses that for the read-only flag. Add support for it
in qemu-nbd.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Avoid warnings like these by wrapping recv():
CC slirp/ip_icmp.o
/src/qemu/slirp/ip_icmp.c: In function 'icmp_receive':
/src/qemu/slirp/ip_icmp.c:418:5: error: passing argument 2 of 'recv' from incompatible pointer type [-Werror]
/usr/local/lib/gcc/i686-mingw32msvc/4.6.0/../../../../i686-mingw32msvc/include/winsock2.h:547:32: note: expected 'char *' but argument is of type 'struct icmp *'
Remove also casts used to avoid warnings.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This commit has the side-effect of making the qemu-nbd binary
capable of binding to IPv6 addresses. ("-b ::1", for instance).
block/nbd.c fails to parse IPv6 IP addresses correctly at this
point, but will work over IPv6 when given a hostname. It still
works over IPv4 as before.
We move the qemu-sockets object from the 'common' to the 'block'
list in the Makefile. The common list includes the block list,
so this is effectively a no-op for the rest of the code.
We also add 32-bit 'magic' attributes to nbd_(request|reply) to
facilitate calculating maximum request/response sizes later.
Signed-off-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch allows to reduce the boot time from an NBD server from 225 seconds to
5 seconds (time between the "boot cd:0" and the kernel init) for the
following command lines:
./qemu-nbd -t ../ISO/debian-500-powerpc-netinst.iso
and
./ppc-softmmu/qemu-system-ppc -cdrom nbd:localhost:1024
This patch combines the reply header and payload send operation.
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch allows to connect Qemu using NBD protocol to an nbd-server
using named exports.
For instance, if on the host "isoserver", in /etc/nbd-server/config, you have:
[generic]
[debian-500-ppc-netinst]
exportname = /ISO/debian-500-powerpc-netinst.iso
[Fedora-10-ppc-netinst]
exportname = /ISO/Fedora-10-ppc-netinst.iso
You can connect to it, using:
qemu -cdrom nbd:isoserver:exportname=debian-500-ppc-netinst
qemu -cdrom nbd:isoserver:exportname=Fedora-10-ppc-netinst
NOTE: you need at least nbd-server 2.9.18
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The attached patch updates the FSF address in the GPL/LGPL boilerplate
in most GPL/LGPLed files, and also in COPYING.LIB.
Signed-off-by: Stuart Brady <stuart.brady@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6162 c046a42c-6fe2-441c-8c8c-71466251a162
Right now, we sprinkle #if defined(QEMU_IMG) && defined(QEMU_NBD) all over the
code. It's ugly and causes us to have to build multiple object files for
linking against qemu and the tools.
This patch introduces a new file, qemu-tool.c which contains enough for
qemu-img, qemu-nbd, and QEMU to all share the same objects.
This also required getting qemu-nbd to be a bit more Windows friendly. I also
changed the Windows block-raw to use normal IO instead of overlapping IO since
we don't actually do AIO yet on Windows. I changed the various #if 0's to
#if WIN32_AIO to make it easier for someone to eventually fix AIO on Windows.
After this patch, there are no longer any #ifdef's related to qemu-img and
qemu-nbd.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5226 c046a42c-6fe2-441c-8c8c-71466251a162
This patch removes "BlockDriverState *bs" from nbd_negotiate() because
it is not used.
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.fr>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5186 c046a42c-6fe2-441c-8c8c-71466251a162
Compilation of QEMU is currently broken on Solaris due to nbd's use of _IO and
due to network libraries not being linked into qemu-img.
The attached patch adds the appropriate libraries (copied from Makefile.target)
and includes an additional Sun-specific header for _IO.
With these fixes it compiles okay, on OpenSolaris snv_93 (amd64).
Signed-off-by: Andreas Faerber <andreas.faerber@web.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4982 c046a42c-6fe2-441c-8c8c-71466251a162
