Drop the assumption that we're using the main AioContext.  Convert
qemu_aio_set_fd_handler() calls to aio_set_fd_handler().

The .bdrv_detach/attach_aio_context() interfaces also need to be
implemented to move the socket fd handler from the old to the new
AioContext.
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Using error_is_set(errp) to check whether a function call failed is
fragile: it breaks when errp is null.  Check perfectly suitable return
values instead when possible.  errp can't be null there now, but this
is more robust and more obviously correct
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Before:
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd
    one of path and host must be specified.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument

After:
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd
    qemu-io: can't open device (null): one of path and host must be specified.
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    qemu-io: can't open device (null): path and host may not be used at the same time.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Before:
    $ qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd
    qemu-io-old: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io-old
    qemu-io-old> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io-old: can't open device (null): Could not open image: Invalid argument

After:
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd
    one of path and host must be specified.
    qemu-io: can't open device (null): Could not open image: Invalid argument
    $ ./qemu-io
    qemu-io> open -r -o file.driver=nbd,file.host=foo,file.path=bar
    path and host may not be used at the same time.
    qemu-io: can't open device (null): Could not open image: Invalid argument

Next patch will fix the error propagation.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out.  Unnecessarily hard for
optimizers, static checkers, and human readers.  Dumb it down to
obvious.

Gets rid of several dozen Coverity false positives.

Note that the obvious form is already used in many places.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

This is a boiler-plate _nofail variant of qemu_opts_create. Remove and
use error_abort in call sites.

null/0 arguments needs to be added for the id and fail_if_exists fields
in affected callsites due to argument inconsistency between the normal and
no_fail variants.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

There is no need to keep the export name around, and it seems a better
fit as an argument in the init() call.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Add an Error ** parameter to BlockDriver.bdrv_open and
BlockDriver.bdrv_file_open to allow more specific error messages.
Signed-off-by: NMax Reitz <mreitz@redhat.com>

The .io_flush() handler no longer exists and has no users.  Drop the
io_flush argument to aio_set_fd_handler() and related functions.

The AioFlushEventNotifierHandler and AioFlushHandler typedefs are no
longer used and are dropped too.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

.io_flush() is no longer called so drop nbd_have_request().  We cannot
drop in_flight since it is still used by other block/nbd.c code.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Otherwise they would get passed to getaddrinfo and fail with:
address resolution failed for [::1]🔢 Name or service not known

(Broken by commit v1.4.0-736-gf17c90be)
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NDong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

It is unused now in all block drivers.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Disable the Nagle algorithm to reduce latency.  Note this means we must
also use TCP_CORK when sending header followed by payload to avoid
fragmenting lots of little packets.  The previous patch took care of
that.
Suggested-by: NNick Thomas <nick@bytemark.co.uk>
Tested-by: NNick Thomas <nick@bytemark.co.uk>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Use TCP_CORK to defer packet transmission until both the header and the
payload have been written.
Suggested-by: NNick Thomas <nick@bytemark.co.uk>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Cc: qemu-stable@nongnu.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The fcntl(fd, F_SETFL, O_NONBLOCK) flag is not specific to sockets.
Rename to qemu_set_nonblock() just like qemu_set_cloexec().
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

A file name may only specified if no host or socket path is specified.
The latter two may not appear at the same time either.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The URL method already takes care to apply the default port when none is
specfied. Directly specifying driver-specific options required the port
number until now. Allow leaving it out and apply the default.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

If a driver needs structured data and not just a string, it can provide
a .bdrv_parse_filename callback now that parses the command line string
into separate options. Keeping this separate from .bdrv_open_filename
ensures that the preferred way of directly specifying the options always
works as well if parsing the string works.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The existing parsers for the file name now parse everything into the
bdrv_open() options QDict. Instead of using these parsers, you can now
directly specify the options on the command line, like this:

    qemu-system-x86_64 -drive file=nbd:,file.port=1234,file.host=::1

Clearly the file=... part could use further improvement, but it's a
start.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The NBD block supports an URL syntax, for which a URL parser returns
separate hostname and port fields. It also supports the traditional qemu
syntax encoded in a filename. Until now, after parsing the URL to get
each piece of information, a new string is built to be fed to socket
functions.

Instead of building a string in the URL case that is immediately parsed
again, parse the string in both cases and use the QemuOpts interface to
qemu-sockets.c.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The new parameter is unused yet.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

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

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

The URI syntax is consistent with the Gluster syntax.  Export names
are specified in the path, preceded by one or more (otherwise unused)
slashes.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Adding the "is_unix" member now will simplify the parsing of NBD URIs.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The same as for non-coroutine versions in previous
patches: rename arguments to be more obvious, change
type of arguments from int to size_t where appropriate,
and use common code for send and receive paths (with
one extra argument) since these are exactly the same.
Use common iov_send_recv() directly.

qemu_co_sendv(), qemu_co_recvv(), and qemu_co_recv()
are now trivial #define's merely adding one extra arg.

qemu_co_sendv() and qemu_co_recvv() callers are
converted to different argument order and extra
`iov_cnt' argument.
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

s->sock is assigned only afterwards, so we're really registering an
aio_fd_handler for file descriptor 0 here. Not exactly what we intended.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Both unused after the previous patch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

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: NLaurent Vivier <laurent@vivier.eu>
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>

This can happen with a buggy or malicious server.
Reported-by: NMichael Tokarev <mjt@tls.msk.ru>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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

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

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

Allow sending up to 16 requests, and drive the replies to the coroutine
that did the request.  The code is written to be exactly the same as
before this patch when MAX_NBD_REQUESTS == 1 (modulo the extra mutex
and state).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

qemu-nbd has a limit of slightly less than 1M per request.  Work
around this in the nbd block driver.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>