nbd-server: Allow node name for nbd-server-add

There is no reason why an NBD server couldn't be started for any node,
even if it's not on the top level. This converts nbd-server-add to
accept a node-name.

Note that there is a semantic difference between using a BlockBackend
name and the node name of its root: In the former case, the NBD server
is closed on eject; in the latter case, the NBD server doesn't drop its
reference and keeps the image file open this way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-07-06 14:15:51 +02:00
parent cd7fca952c
commit 094138d09e
2 changed files with 11 additions and 14 deletions

View File

@ -145,7 +145,8 @@ void qmp_nbd_server_start(SocketAddress *addr,
void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
Error **errp)
{
BlockBackend *blk;
BlockDriverState *bs = NULL;
BlockBackend *on_eject_blk;
NBDExport *exp;
if (!nbd_server) {
@ -158,26 +159,22 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
return;
}
blk = blk_by_name(device);
if (!blk) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
"Device '%s' not found", device);
return;
}
if (!blk_is_inserted(blk)) {
error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
on_eject_blk = blk_by_name(device);
bs = bdrv_lookup_bs(device, device, errp);
if (!bs) {
return;
}
if (!has_writable) {
writable = false;
}
if (blk_is_read_only(blk)) {
if (bdrv_is_read_only(bs)) {
writable = false;
}
exp = nbd_export_new(blk_bs(blk), 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
NULL, false, blk, errp);
exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
NULL, false, on_eject_blk, errp);
if (!exp) {
return;
}

View File

@ -161,9 +161,9 @@
##
# @nbd-server-add:
#
# Export a device to QEMU's embedded NBD server.
# Export a block node to QEMU's embedded NBD server.
#
# @device: Block device to be exported
# @device: The device name or node name of the node to be exported
#
# @writable: Whether clients should be able to write to the device via the
# NBD connection (default false). #optional