qemu-nbd was broken because they initialized the block layer while
qemu_aio_context was still NULL.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Use a simple state machine with the following states:

- RUNNING     => accepting connections
- TERMINATE   => main loop must call nbd_export_close/put, and not accept
  connections anymore
- TERMINATING => waiting for pending requests to finish
- TERMINATED  => the NBDExport has been closed
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

In order to exit cleanly from qemu-nbd, add a callback that triggers
when an NBDExport is closed.  In the case of qemu-nbd it will exit the
main loop.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We will use a similar two-phase destruction for NBDExport, so we need
each NBDClient to add a reference to NBDExport.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is not desirable when embedding the NBD server inside QEMU.
Move the bdrv_close to qemu-nbd.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add two options to tune the I/O implementation of qemu-nbd, matching
the possibilities given by the QEMU -drive option.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch separates qemu-nbd's options in logical groups, thus making
the help message easier to read.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo 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: NPaolo Bonzini <pbonzini@redhat.com>

This prepares for the following patch, which changes -1 return values
to negative errno.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When qemu-nbd becomes a daemon it calls daemon(3) with
nochdir=0, so daemon(3) changes current directory to /.
But at this time, qemu-nbd did not open any user-specified
files yet, so by changing current directory, all non-absolute
paths becomes wrong.  The solution is to pass nochdir=1 to
daemon(3) function, and to chdir("/") after all init has
been performed, before entering the main loop, -- just like
a good daemon should do.

This patch is applicable for -stable.
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

For some reason nbd_client_thread() has a do..while loop which can never
loop, the condition is bogus because we would take a goto instead.  Drop
the loop.
Reported-by: NDr David Alan Gilbert <davidagilbert@uk.ibm.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.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: NPaolo Bonzini <pbonzini@redhat.com>

Using a single main loop for sockets will help yielding from the socket
coroutine back to the main loop, and later reentering it.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Wrap the common parameters of nbd_trip and nbd_negotiate in a
single opaque struct.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The size of the buffer is in practice part of the protocol.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The argument is write-only.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is cleaner, because we do not need to close the block device when
there is an error opening /dev/nbdX.  It was done this way only to
print errors before daemonizing.

At the same time, use atexit to ensure that the block device is closed
whenever we exit.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Now that the client and server are in the same process, there is
no need to race on the creation of the socket.  We can open the
listening socket before starting the client thread.

This avoids that "qemu-nbd -v -c" prints this once before connecting
successfully to the socket:

    connect(unix:/var/lock/qemu-nbd-nbd0): No such file or directory
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

In order to get nice error messages, keep the qemu-nbd process running
until before issuing NBD_DO_IT and connected to the daemon with a pipe.
This lets the qemu-nbd process relay error messages from the daemon and
exit with a nonzero status if appropriate.
Suggested-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This avoids that qemu-nbd uses both forking and threads, which do
not behave well together.

qemu-nbd is already Unix only, and there is no qemu_thread_join,
so for now use pthreads.

Since the parent and child no longer have separate file descriptors,
we can open the NBD device before daemonizing, instead of checking
with access(2) and restricting the open to the client only.
Reported-by: NPierre Riteau <pierre.riteau@irisa.fr>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

It will be moved to a global variable by the next patch, and it
would conflict with the socket function.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The client process right now uses SIGTERM to interrupt the server side.
This does not affect the exit status of "qemu-nbd -v -c" because the
server is a child process.  This will change when both sides will be
in the same process, and anyway cleaning up things nicely upon SIGTERM
is good practice.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin 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: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

* qemu-common.h is not a system include file, so it should be included
  with "" instead of <>. Otherwise incremental builds might fail
  because only local include files are checked for changes.

* linux-user/syscall.c included the file twice.

Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

qemu_malloc/qemu_free no longer exist after this commit.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Changes since v1: create a wrapper function named qemu_daemon() in oslib-posix.c
instead of putting the OS specific workaround in qemu-nbd.c directly.

On OSX >= 10.5, daemon() is deprecated, resulting in the following warning:
----8<----
qemu-nbd.c: In function ‘main’:
qemu-nbd.c:371: warning: ‘daemon’ is deprecated (declared at /usr/include/stdlib.h:289)
----8<----

The following trick, used in mDNSResponder, takes care of this warning:
http://www.opensource.apple.com/source/mDNSResponder/mDNSResponder-258.18/mDNSPosix/PosixDaemon.c

On OSX, it temporarily renames the daemon() function before including stdlib.h
and declares it manually as an extern function. This way, the compiler does not
see the declaration from stdlib.h and thus does not display the warning.
Signed-off-by: NAlexandre Raymond <cerbere@gmail.com>
Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: NAndreas Färber <andreas.faerber@web.de>

Change BDRV_O_NOCACHE to only imply bypassing the host OS file cache,
but no writeback semantics.  All existing callers are changed to also
specify BDRV_O_CACHE_WB to give them writeback semantics.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

It's an indirect call to qemu_malloc, which never returns an error.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/nbd.c: use default port number when none is specified
qemu-nbd.c:  use IANA-assigned port number: 10809
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Use qemu_blockalign for all allocations in the block layer.  This allows
increasing the required alignment, which is need to support O_DIRECT on
devices with large block sizes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.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: NLaurent Vivier <laurent@vivier.eu>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

- use err(3) instead of errx(3) if errno is available
  to report why failed
- let fail prior to daemon(3) if opening a nbd file
  is likely to fail after daemonizing to avoid silent
  failure exit
- add missing 'ret = 1' when unix_socket_outgoing failed
Signed-off-by: NRyota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

What is known today as bdrv_open2 becomes the new bdrv_open. All remaining
callers of the old function are converted to the new one. In some places they
even know the right format, so they should have used bdrv_open2 from the
beginning.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

errx takes the exit status of a process as the first
argument. Passing errno to it is wrong. Instead the
patch lets errx take EXIT_FAILURE.
Signed-off-by: NRyota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

bdrv_open may return -errno so we have to check
if the return value is '< 0', not '== -1'.
Signed-off-by: NRyota Ozaki <ozaki.ryota@gmail.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

Really use read-only flags for opening the file when asked for read-only
Signed-off-by: NNaphtali Sprei <nsprei@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>