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qemu/hw/block/xen-block.c
Paul Durrant ef916ab3ec xen-block: treat XenbusStateUnknown the same as XenbusStateClosed 
When a frontend gracefully disconnects from an offline backend, it will
set its own state to XenbusStateClosed. The code in xen-block.c correctly
deals with this and sets the backend into XenbusStateClosed. Unfortunately
it is possible for toolstack to actually delete the frontend area
before the state key has been read, leading to an apparent frontend state
of XenbusStateUnknown. This prevents the backend state from transitioning
to XenbusStateClosed and hence leaves it limbo.

This patch simply treats a frontend state of XenbusStateUnknown the same
as XenbusStateClosed, which will unblock the backend in these circumstances.

Reported-by: Mark Syms <mark.syms@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20190918115702.38959-1-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-09-24 12:21:11 +01:00

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/*
* Copyright (c) 2018 Citrix Systems Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/cutils.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-block-core.h"
#include "qapi/qapi-commands-qom.h"
#include "qapi/qapi-visit-block-core.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/visitor.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "hw/xen/xen_common.h"
#include "hw/block/xen_blkif.h"
#include "hw/qdev-properties.h"
#include "hw/xen/xen-block.h"
#include "hw/xen/xen-backend.h"
#include "sysemu/blockdev.h"
#include "sysemu/block-backend.h"
#include "sysemu/iothread.h"
#include "dataplane/xen-block.h"
#include "trace.h"
static char *xen_block_get_name(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
return g_strdup_printf("%lu", vdev->number);
}
static void xen_block_disconnect(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
trace_xen_block_disconnect(type, vdev->disk, vdev->partition);
xen_block_dataplane_stop(blockdev->dataplane);
}
static void xen_block_connect(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
unsigned int feature_large_sector_size;
unsigned int order, nr_ring_ref, *ring_ref, event_channel, protocol;
char *str;
trace_xen_block_connect(type, vdev->disk, vdev->partition);
if (xen_device_frontend_scanf(xendev, "feature-large-sector-size", "%u",
&feature_large_sector_size) != 1) {
feature_large_sector_size = 0;
}
if (feature_large_sector_size != 1 &&
conf->logical_block_size != XEN_BLKIF_SECTOR_SIZE) {
error_setg(errp, "logical_block_size != %u not supported by frontend",
XEN_BLKIF_SECTOR_SIZE);
return;
}
if (xen_device_frontend_scanf(xendev, "ring-page-order", "%u",
&order) != 1) {
nr_ring_ref = 1;
ring_ref = g_new(unsigned int, nr_ring_ref);
if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
&ring_ref[0]) != 1) {
error_setg(errp, "failed to read ring-ref");
g_free(ring_ref);
return;
}
} else if (order <= blockdev->props.max_ring_page_order) {
unsigned int i;
nr_ring_ref = 1 << order;
ring_ref = g_new(unsigned int, nr_ring_ref);
for (i = 0; i < nr_ring_ref; i++) {
const char *key = g_strdup_printf("ring-ref%u", i);
if (xen_device_frontend_scanf(xendev, key, "%u",
&ring_ref[i]) != 1) {
error_setg(errp, "failed to read %s", key);
g_free((gpointer)key);
g_free(ring_ref);
return;
}
g_free((gpointer)key);
}
} else {
error_setg(errp, "invalid ring-page-order (%d)", order);
return;
}
if (xen_device_frontend_scanf(xendev, "event-channel", "%u",
&event_channel) != 1) {
error_setg(errp, "failed to read event-channel");
g_free(ring_ref);
return;
}
if (xen_device_frontend_scanf(xendev, "protocol", "%ms",
&str) != 1) {
protocol = BLKIF_PROTOCOL_NATIVE;
} else {
if (strcmp(str, XEN_IO_PROTO_ABI_X86_32) == 0) {
protocol = BLKIF_PROTOCOL_X86_32;
} else if (strcmp(str, XEN_IO_PROTO_ABI_X86_64) == 0) {
protocol = BLKIF_PROTOCOL_X86_64;
} else {
protocol = BLKIF_PROTOCOL_NATIVE;
}
free(str);
}
xen_block_dataplane_start(blockdev->dataplane, ring_ref, nr_ring_ref,
event_channel, protocol, errp);
g_free(ring_ref);
}
static void xen_block_unrealize(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockDeviceClass *blockdev_class =
XEN_BLOCK_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
return;
}
trace_xen_block_unrealize(type, vdev->disk, vdev->partition);
/* Disconnect from the frontend in case this has not already happened */
xen_block_disconnect(xendev, NULL);
xen_block_dataplane_destroy(blockdev->dataplane);
blockdev->dataplane = NULL;
if (blockdev_class->unrealize) {
blockdev_class->unrealize(blockdev, errp);
}
}
static void xen_block_set_size(XenBlockDevice *blockdev)
{
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size;
XenDevice *xendev = XEN_DEVICE(blockdev);
trace_xen_block_size(type, vdev->disk, vdev->partition, sectors);
xen_device_backend_printf(xendev, "sectors", "%"PRIi64, sectors);
}
static void xen_block_resize_cb(void *opaque)
{
XenBlockDevice *blockdev = opaque;
XenDevice *xendev = XEN_DEVICE(blockdev);
enum xenbus_state state = xen_device_backend_get_state(xendev);
xen_block_set_size(blockdev);
/*
* Mimic the behaviour of Linux xen-blkback and re-write the state
* to trigger the frontend watch.
*/
xen_device_backend_printf(xendev, "state", "%u", state);
}
static const BlockDevOps xen_block_dev_ops = {
.resize_cb = xen_block_resize_cb,
};
static void xen_block_realize(XenDevice *xendev, Error **errp)
{
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockDeviceClass *blockdev_class =
XEN_BLOCK_DEVICE_GET_CLASS(xendev);
const char *type = object_get_typename(OBJECT(blockdev));
XenBlockVdev *vdev = &blockdev->props.vdev;
BlockConf *conf = &blockdev->props.conf;
BlockBackend *blk = conf->blk;
Error *local_err = NULL;
if (vdev->type == XEN_BLOCK_VDEV_TYPE_INVALID) {
error_setg(errp, "vdev property not set");
return;
}
trace_xen_block_realize(type, vdev->disk, vdev->partition);
if (blockdev_class->realize) {
blockdev_class->realize(blockdev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
}
/*
* The blkif protocol does not deal with removable media, so it must
* always be present, even for CDRom devices.
*/
assert(blk);
if (!blk_is_inserted(blk)) {
error_setg(errp, "device needs media, but drive is empty");
return;
}
if (!blkconf_apply_backend_options(conf, blockdev->info & VDISK_READONLY,
true, errp)) {
return;
}
if (!(blockdev->info & VDISK_CDROM) &&
!blkconf_geometry(conf, NULL, 65535, 255, 255, errp)) {
return;
}
blkconf_blocksizes(conf);
if (conf->logical_block_size > conf->physical_block_size) {
error_setg(
errp, "logical_block_size > physical_block_size not supported");
return;
}
blk_set_dev_ops(blk, &xen_block_dev_ops, blockdev);
blk_set_guest_block_size(blk, conf->logical_block_size);
if (conf->discard_granularity == -1) {
conf->discard_granularity = conf->physical_block_size;
}
if (blk_get_flags(blk) & BDRV_O_UNMAP) {
xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
xen_device_backend_printf(xendev, "discard-granularity", "%u",
conf->discard_granularity);
}
xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
xen_device_backend_printf(xendev, "max-ring-page-order", "%u",
blockdev->props.max_ring_page_order);
xen_device_backend_printf(xendev, "info", "%u", blockdev->info);
xen_device_frontend_printf(xendev, "virtual-device", "%lu",
vdev->number);
xen_device_frontend_printf(xendev, "device-type", "%s",
blockdev->device_type);
xen_device_backend_printf(xendev, "sector-size", "%u",
conf->logical_block_size);
xen_block_set_size(blockdev);
blockdev->dataplane =
xen_block_dataplane_create(xendev, blk, conf->logical_block_size,
blockdev->props.iothread);
}
static void xen_block_frontend_changed(XenDevice *xendev,
enum xenbus_state frontend_state,
Error **errp)
{
enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
Error *local_err = NULL;
switch (frontend_state) {
case XenbusStateInitialised:
case XenbusStateConnected:
if (backend_state == XenbusStateConnected) {
break;
}
xen_block_disconnect(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
break;
}
xen_block_connect(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
break;
}
xen_device_backend_set_state(xendev, XenbusStateConnected);
break;
case XenbusStateClosing:
xen_device_backend_set_state(xendev, XenbusStateClosing);
break;
case XenbusStateClosed:
case XenbusStateUnknown:
xen_block_disconnect(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
break;
}
xen_device_backend_set_state(xendev, XenbusStateClosed);
break;
default:
break;
}
}
static char *disk_to_vbd_name(unsigned int disk)
{
char *name, *prefix = (disk >= 26) ?
disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
name = g_strdup_printf("%s%c", prefix, 'a' + disk % 26);
g_free(prefix);
return name;
}
static void xen_block_get_vdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
char *str;
switch (vdev->type) {
case XEN_BLOCK_VDEV_TYPE_DP:
str = g_strdup_printf("d%lup%lu", vdev->disk, vdev->partition);
break;
case XEN_BLOCK_VDEV_TYPE_XVD:
case XEN_BLOCK_VDEV_TYPE_HD:
case XEN_BLOCK_VDEV_TYPE_SD: {
char *name = disk_to_vbd_name(vdev->disk);
str = g_strdup_printf("%s%s%lu",
(vdev->type == XEN_BLOCK_VDEV_TYPE_XVD) ?
"xvd" :
(vdev->type == XEN_BLOCK_VDEV_TYPE_HD) ?
"hd" :
"sd",
name, vdev->partition);
g_free(name);
break;
}
default:
error_setg(errp, "invalid vdev type");
return;
}
visit_type_str(v, name, &str, errp);
g_free(str);
}
static int vbd_name_to_disk(const char *name, const char **endp,
unsigned long *disk)
{
unsigned int n = 0;
while (*name != '\0') {
if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
break;
}
n *= 26;
n += *name++ - 'a' + 1;
}
*endp = name;
if (!n) {
return -1;
}
*disk = n - 1;
return 0;
}
static void xen_block_set_vdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
XenBlockVdev *vdev = qdev_get_prop_ptr(dev, prop);
Error *local_err = NULL;
char *str, *p;
const char *end;
if (dev->realized) {
qdev_prop_set_after_realize(dev, name, errp);
return;
}
visit_type_str(v, name, &str, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
p = strchr(str, 'd');
if (!p) {
goto invalid;
}
*p++ = '\0';
if (*str == '\0') {
vdev->type = XEN_BLOCK_VDEV_TYPE_DP;
} else if (strcmp(str, "xv") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_XVD;
} else if (strcmp(str, "h") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_HD;
} else if (strcmp(str, "s") == 0) {
vdev->type = XEN_BLOCK_VDEV_TYPE_SD;
} else {
goto invalid;
}
if (vdev->type == XEN_BLOCK_VDEV_TYPE_DP) {
if (qemu_strtoul(p, &end, 10, &vdev->disk)) {
goto invalid;
}
if (*end == 'p') {
if (*(++end) == '\0') {
goto invalid;
}
}
} else {
if (vbd_name_to_disk(p, &end, &vdev->disk)) {
goto invalid;
}
}
if (*end != '\0') {
p = (char *)end;
if (qemu_strtoul(p, &end, 10, &vdev->partition)) {
goto invalid;
}
if (*end != '\0') {
goto invalid;
}
} else {
vdev->partition = 0;
}
switch (vdev->type) {
case XEN_BLOCK_VDEV_TYPE_DP:
case XEN_BLOCK_VDEV_TYPE_XVD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
vdev->number = (202 << 8) | (vdev->disk << 4) |
vdev->partition;
} else if (vdev->disk < (1 << 20) && vdev->partition < (1 << 8)) {
vdev->number = (1 << 28) | (vdev->disk << 8) |
vdev->partition;
} else {
goto invalid;
}
break;
case XEN_BLOCK_VDEV_TYPE_HD:
if ((vdev->disk == 0 || vdev->disk == 1) &&
vdev->partition < (1 << 6)) {
vdev->number = (3 << 8) | (vdev->disk << 6) | vdev->partition;
} else if ((vdev->disk == 2 || vdev->disk == 3) &&
vdev->partition < (1 << 6)) {
vdev->number = (22 << 8) | ((vdev->disk - 2) << 6) |
vdev->partition;
} else {
goto invalid;
}
break;
case XEN_BLOCK_VDEV_TYPE_SD:
if (vdev->disk < (1 << 4) && vdev->partition < (1 << 4)) {
vdev->number = (8 << 8) | (vdev->disk << 4) | vdev->partition;
} else {
goto invalid;
}
break;
default:
goto invalid;
}
g_free(str);
return;
invalid:
error_setg(errp, "invalid virtual disk specifier");
vdev->type = XEN_BLOCK_VDEV_TYPE_INVALID;
g_free(str);
}
/*
* This property deals with 'vdev' names adhering to the Xen VBD naming
* scheme described in:
*
* https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
*/
const PropertyInfo xen_block_prop_vdev = {
.name = "str",
.description = "Virtual Disk specifier: d*p*/xvd*/hd*/sd*",
.get = xen_block_get_vdev,
.set = xen_block_set_vdev,
};
static Property xen_block_props[] = {
DEFINE_PROP("vdev", XenBlockDevice, props.vdev,
xen_block_prop_vdev, XenBlockVdev),
DEFINE_BLOCK_PROPERTIES(XenBlockDevice, props.conf),
DEFINE_PROP_UINT32("max-ring-page-order", XenBlockDevice,
props.max_ring_page_order, 4),
DEFINE_PROP_LINK("iothread", XenBlockDevice, props.iothread,
TYPE_IOTHREAD, IOThread *),
DEFINE_PROP_END_OF_LIST()
};
static void xen_block_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
xendev_class->backend = "qdisk";
xendev_class->device = "vbd";
xendev_class->get_name = xen_block_get_name;
xendev_class->realize = xen_block_realize;
xendev_class->frontend_changed = xen_block_frontend_changed;
xendev_class->unrealize = xen_block_unrealize;
dev_class->props = xen_block_props;
}
static const TypeInfo xen_block_type_info = {
.name = TYPE_XEN_BLOCK_DEVICE,
.parent = TYPE_XEN_DEVICE,
.instance_size = sizeof(XenBlockDevice),
.abstract = true,
.class_size = sizeof(XenBlockDeviceClass),
.class_init = xen_block_class_init,
};
static void xen_disk_unrealize(XenBlockDevice *blockdev, Error **errp)
{
trace_xen_disk_unrealize();
}
static void xen_disk_realize(XenBlockDevice *blockdev, Error **errp)
{
BlockConf *conf = &blockdev->props.conf;
trace_xen_disk_realize();
blockdev->device_type = "disk";
if (!conf->blk) {
error_setg(errp, "drive property not set");
return;
}
blockdev->info = blk_is_read_only(conf->blk) ? VDISK_READONLY : 0;
}
static void xen_disk_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
blockdev_class->realize = xen_disk_realize;
blockdev_class->unrealize = xen_disk_unrealize;
dev_class->desc = "Xen Disk Device";
}
static const TypeInfo xen_disk_type_info = {
.name = TYPE_XEN_DISK_DEVICE,
.parent = TYPE_XEN_BLOCK_DEVICE,
.instance_size = sizeof(XenDiskDevice),
.class_init = xen_disk_class_init,
};
static void xen_cdrom_unrealize(XenBlockDevice *blockdev, Error **errp)
{
trace_xen_cdrom_unrealize();
}
static void xen_cdrom_realize(XenBlockDevice *blockdev, Error **errp)
{
BlockConf *conf = &blockdev->props.conf;
trace_xen_cdrom_realize();
blockdev->device_type = "cdrom";
if (!conf->blk) {
int rc;
/* Set up an empty drive */
conf->blk = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
rc = blk_attach_dev(conf->blk, DEVICE(blockdev));
if (!rc) {
error_setg_errno(errp, -rc, "failed to create drive");
return;
}
}
blockdev->info = VDISK_READONLY | VDISK_CDROM;
}
static void xen_cdrom_class_init(ObjectClass *class, void *data)
{
DeviceClass *dev_class = DEVICE_CLASS(class);
XenBlockDeviceClass *blockdev_class = XEN_BLOCK_DEVICE_CLASS(class);
blockdev_class->realize = xen_cdrom_realize;
blockdev_class->unrealize = xen_cdrom_unrealize;
dev_class->desc = "Xen CD-ROM Device";
}
static const TypeInfo xen_cdrom_type_info = {
.name = TYPE_XEN_CDROM_DEVICE,
.parent = TYPE_XEN_BLOCK_DEVICE,
.instance_size = sizeof(XenCDRomDevice),
.class_init = xen_cdrom_class_init,
};
static void xen_block_register_types(void)
{
type_register_static(&xen_block_type_info);
type_register_static(&xen_disk_type_info);
type_register_static(&xen_cdrom_type_info);
}
type_init(xen_block_register_types)
static void xen_block_blockdev_del(const char *node_name, Error **errp)
{
trace_xen_block_blockdev_del(node_name);
qmp_blockdev_del(node_name, errp);
}
static char *xen_block_blockdev_add(const char *id, QDict *qdict,
Error **errp)
{
const char *driver = qdict_get_try_str(qdict, "driver");
BlockdevOptions *options = NULL;
Error *local_err = NULL;
char *node_name;
Visitor *v;
if (!driver) {
error_setg(errp, "no 'driver' parameter");
return NULL;
}
node_name = g_strdup_printf("%s-%s", id, driver);
qdict_put_str(qdict, "node-name", node_name);
trace_xen_block_blockdev_add(node_name);
v = qobject_input_visitor_new(QOBJECT(qdict));
visit_type_BlockdevOptions(v, NULL, &options, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
qmp_blockdev_add(options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
qapi_free_BlockdevOptions(options);
return node_name;
fail:
if (options) {
qapi_free_BlockdevOptions(options);
}
g_free(node_name);
return NULL;
}
static void xen_block_drive_destroy(XenBlockDrive *drive, Error **errp)
{
char *node_name = drive->node_name;
if (node_name) {
Error *local_err = NULL;
xen_block_blockdev_del(node_name, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
g_free(node_name);
drive->node_name = NULL;
}
g_free(drive->id);
g_free(drive);
}
static XenBlockDrive *xen_block_drive_create(const char *id,
const char *device_type,
QDict *opts, Error **errp)
{
const char *params = qdict_get_try_str(opts, "params");
const char *mode = qdict_get_try_str(opts, "mode");
const char *direct_io_safe = qdict_get_try_str(opts, "direct-io-safe");
const char *discard_enable = qdict_get_try_str(opts, "discard-enable");
char *driver = NULL;
char *filename = NULL;
XenBlockDrive *drive = NULL;
Error *local_err = NULL;
QDict *file_layer;
QDict *driver_layer;
if (params) {
char **v = g_strsplit(params, ":", 2);
if (v[1] == NULL) {
filename = g_strdup(v[0]);
driver = g_strdup("raw");
} else {
if (strcmp(v[0], "aio") == 0) {
driver = g_strdup("raw");
} else if (strcmp(v[0], "vhd") == 0) {
driver = g_strdup("vpc");
} else {
driver = g_strdup(v[0]);
}
filename = g_strdup(v[1]);
}
g_strfreev(v);
} else {
error_setg(errp, "no params");
goto done;
}
assert(filename);
assert(driver);
drive = g_new0(XenBlockDrive, 1);
drive->id = g_strdup(id);
file_layer = qdict_new();
driver_layer = qdict_new();
qdict_put_str(file_layer, "driver", "file");
qdict_put_str(file_layer, "filename", filename);
g_free(filename);
if (mode && *mode != 'w') {
qdict_put_bool(file_layer, "read-only", true);
}
if (direct_io_safe) {
unsigned long value;
if (!qemu_strtoul(direct_io_safe, NULL, 2, &value) && !!value) {
QDict *cache_qdict = qdict_new();
qdict_put_bool(cache_qdict, "direct", true);
qdict_put(file_layer, "cache", cache_qdict);
qdict_put_str(file_layer, "aio", "native");
}
}
if (discard_enable) {
unsigned long value;
if (!qemu_strtoul(discard_enable, NULL, 2, &value) && !!value) {
qdict_put_str(file_layer, "discard", "unmap");
qdict_put_str(driver_layer, "discard", "unmap");
}
}
/*
* It is necessary to turn file locking off as an emulated device
* may have already opened the same image file.
*/
qdict_put_str(file_layer, "locking", "off");
qdict_put_str(driver_layer, "driver", driver);
g_free(driver);
qdict_put(driver_layer, "file", file_layer);
g_assert(!drive->node_name);
drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
&local_err);
qobject_unref(driver_layer);
done:
if (local_err) {
error_propagate(errp, local_err);
xen_block_drive_destroy(drive, NULL);
return NULL;
}
return drive;
}
static const char *xen_block_drive_get_node_name(XenBlockDrive *drive)
{
return drive->node_name ? drive->node_name : "";
}
static void xen_block_iothread_destroy(XenBlockIOThread *iothread,
Error **errp)
{
qmp_object_del(iothread->id, errp);
g_free(iothread->id);
g_free(iothread);
}
static XenBlockIOThread *xen_block_iothread_create(const char *id,
Error **errp)
{
XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
Error *local_err = NULL;
iothread->id = g_strdup(id);
qmp_object_add(TYPE_IOTHREAD, id, false, NULL, &local_err);
if (local_err) {
error_propagate(errp, local_err);
g_free(iothread->id);
g_free(iothread);
return NULL;
}
return iothread;
}
static void xen_block_device_create(XenBackendInstance *backend,
QDict *opts, Error **errp)
{
XenBus *xenbus = xen_backend_get_bus(backend);
const char *name = xen_backend_get_name(backend);
unsigned long number;
const char *vdev, *device_type;
XenBlockDrive *drive = NULL;
XenBlockIOThread *iothread = NULL;
XenDevice *xendev = NULL;
Error *local_err = NULL;
const char *type;
XenBlockDevice *blockdev;
if (qemu_strtoul(name, NULL, 10, &number)) {
error_setg(errp, "failed to parse name '%s'", name);
goto fail;
}
trace_xen_block_device_create(number);
vdev = qdict_get_try_str(opts, "dev");
if (!vdev) {
error_setg(errp, "no dev parameter");
goto fail;
}
device_type = qdict_get_try_str(opts, "device-type");
if (!device_type) {
error_setg(errp, "no device-type parameter");
goto fail;
}
if (!strcmp(device_type, "disk")) {
type = TYPE_XEN_DISK_DEVICE;
} else if (!strcmp(device_type, "cdrom")) {
type = TYPE_XEN_CDROM_DEVICE;
} else {
error_setg(errp, "invalid device-type parameter '%s'", device_type);
goto fail;
}
drive = xen_block_drive_create(vdev, device_type, opts, &local_err);
if (!drive) {
error_propagate_prepend(errp, local_err, "failed to create drive: ");
goto fail;
}
iothread = xen_block_iothread_create(vdev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to create iothread: ");
goto fail;
}
xendev = XEN_DEVICE(qdev_create(BUS(xenbus), type));
blockdev = XEN_BLOCK_DEVICE(xendev);
object_property_set_str(OBJECT(xendev), vdev, "vdev", &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err, "failed to set 'vdev': ");
goto fail;
}
object_property_set_str(OBJECT(xendev),
xen_block_drive_get_node_name(drive), "drive",
&local_err);
if (local_err) {
error_propagate_prepend(errp, local_err, "failed to set 'drive': ");
goto fail;
}
object_property_set_str(OBJECT(xendev), iothread->id, "iothread",
&local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to set 'iothread': ");
goto fail;
}
blockdev->iothread = iothread;
blockdev->drive = drive;
object_property_set_bool(OBJECT(xendev), true, "realized", &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"realization of device %s failed: ",
type);
goto fail;
}
xen_backend_set_device(backend, xendev);
return;
fail:
if (xendev) {
object_unparent(OBJECT(xendev));
}
if (iothread) {
xen_block_iothread_destroy(iothread, NULL);
}
if (drive) {
xen_block_drive_destroy(drive, NULL);
}
}
static void xen_block_device_destroy(XenBackendInstance *backend,
Error **errp)
{
XenDevice *xendev = xen_backend_get_device(backend);
XenBlockDevice *blockdev = XEN_BLOCK_DEVICE(xendev);
XenBlockVdev *vdev = &blockdev->props.vdev;
XenBlockDrive *drive = blockdev->drive;
XenBlockIOThread *iothread = blockdev->iothread;
trace_xen_block_device_destroy(vdev->number);
object_unparent(OBJECT(xendev));
if (iothread) {
Error *local_err = NULL;
xen_block_iothread_destroy(iothread, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to destroy iothread: ");
return;
}
}
if (drive) {
Error *local_err = NULL;
xen_block_drive_destroy(drive, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to destroy drive: ");
}
}
}
static const XenBackendInfo xen_block_backend_info = {
.type = "qdisk",
.create = xen_block_device_create,
.destroy = xen_block_device_destroy,
};
static void xen_block_register_backend(void)
{
xen_backend_register(&xen_block_backend_info);
}
xen_backend_init(xen_block_register_backend);
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