upcoming libnfs will feature internal readahead support.
Add a knob to pass the optional readahead value as a URL
parameter.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

this patch fixes the incorrect usage of strncmp and
adds simple error checking by means of parse_uint_full
instead of atoi for the supplied URL parameters.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Now that all backend drivers are using QemuOpts, remove all
QEMUOptionParameter related codes.
Signed-off-by: NDong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: NChunyan Liu <cyliu@suse.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NChunyan Liu <cyliu@suse.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

it will happen in the future that the callback of a libnfs call
directly invokes the callback. In this case we end up in a segfault
because the NFSRPC is gone when we the BH is scheduled.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Drop the assumption that we're using the main AioContext.  The following
functions need to be converted:
 * qemu_bh_new() -> aio_bh_new()
 * qemu_aio_set_fd_handler() -> aio_set_fd_handler()
 * qemu_aio_wait() -> aio_poll()

The .bdrv_detach/attach_aio_context() interfaces also need to be
implemented to move the fd handler from the old to the new AioContext.

Cc: Peter Lieven <pl@kamp.de>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPeter Lieven <pl@kamp.de>

After the URL has been parsed make sure the server part is valid in
order to avoid a segmentation fault when calling nfs_mount().
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@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.  Commit 84d18f06 dumbed
it down to obvious, but a few more have crept in since, and
documentation was overlooked.  Dumb these down, too.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

if an NFS operation fails we should report what libnfs knows
about the failure. It is likely more than just an error code.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch adds native support for accessing images on NFS
shares without the requirement to actually mount the entire
NFS share on the host.

NFS Images can simply be specified by an url of the form:
nfs://<host>/<export>/<filename>[?param=value[&param2=value2[&...]]]

For example:
qemu-img create -f qcow2 nfs://10.0.0.1/qemu-images/test.qcow2

You need LibNFS from Ronnie Sahlberg available at:
   git://github.com/sahlberg/libnfs.git
for this to work.

During configure it is automatically probed for libnfs and support
is enabled on-the-fly. You can forbid or enforce libnfs support
with --disable-libnfs or --enable-libnfs respectively.

Due to NFS restrictions you might need to execute your binaries
as root, allow them to open priviledged ports (<1024) or specify
insecure option on the NFS server.

For additional information on ROOT vs. non-ROOT operation and URL
format + parameters see:
   https://raw.github.com/sahlberg/libnfs/master/README

Supported by qemu are the uid, gid and tcp-syncnt URL parameters.

LibNFS currently support NFS version 3 only.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>