qemu/hw/core/qdev-properties-system.c
Denis V. Lunev 9588c5897b block: add missed aio_context_acquire into release_drive
Recently we expirience hang with iothreads enabled with the following
call trace:
Thread 1 (Thread 0x7fa95efebc80 (LWP 177117)):
0  ppoll () from /lib64/libc.so.6
2  qemu_poll_ns () at qemu-timer.c:313
3  aio_poll () at aio-posix.c:457
4  bdrv_flush () at block/io.c:2641
5  bdrv_close () at block.c:2143
6  bdrv_delete () at block.c:2352
7  bdrv_unref () at block.c:3429
8  blk_remove_bs () at block/block-backend.c:427
9  blk_delete () at block/block-backend.c:178
10 blk_unref () at block/block-backend.c:226
11 object_property_del_all () at qom/object.c:399
12 object_finalize () at qom/object.c:461
13 object_unref () at qom/object.c:898
14 object_property_del_child () at qom/object.c:422
15 qmp_marshal_device_del () at qmp-marshal.c:1145
16 handle_qmp_command () at /usr/src/debug/qemu-2.6.0/monitor.c:3929

Technically bdrv_flush() stucks in
    while (rwco.ret == NOT_DONE) {
        aio_poll(aio_context, true);
    }
but rwco.ret is equal to 0 thus we have missed wakeup. Code investigation
reveals that we do not have performed aio_context_acquire() on this call
stack.

This patch adds missed lock.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Message-id: 1490717566-25516-1-git-send-email-den@openvz.org
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-03 17:11:39 +02:00

450 lines
12 KiB
C

/*
* qdev property parsing
* (parts specific for qemu-system-*)
*
* This file is based on code from hw/qdev-properties.c from
* commit 074a86fccd185616469dfcdc0e157f438aebba18,
* Copyright (c) Gerd Hoffmann <kraxel@redhat.com> and other contributors.
*
* 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 "net/net.h"
#include "hw/qdev.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "sysemu/block-backend.h"
#include "sysemu/blockdev.h"
#include "hw/block/block.h"
#include "net/hub.h"
#include "qapi/visitor.h"
#include "sysemu/char.h"
#include "sysemu/iothread.h"
static void get_pointer(Object *obj, Visitor *v, Property *prop,
char *(*print)(void *ptr),
const char *name, Error **errp)
{
DeviceState *dev = DEVICE(obj);
void **ptr = qdev_get_prop_ptr(dev, prop);
char *p;
p = *ptr ? print(*ptr) : g_strdup("");
visit_type_str(v, name, &p, errp);
g_free(p);
}
static void set_pointer(Object *obj, Visitor *v, Property *prop,
void (*parse)(DeviceState *dev, const char *str,
void **ptr, const char *propname,
Error **errp),
const char *name, Error **errp)
{
DeviceState *dev = DEVICE(obj);
Error *local_err = NULL;
void **ptr = qdev_get_prop_ptr(dev, prop);
char *str;
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;
}
if (!*str) {
g_free(str);
*ptr = NULL;
return;
}
parse(dev, str, ptr, prop->name, errp);
g_free(str);
}
/* --- drive --- */
static void parse_drive(DeviceState *dev, const char *str, void **ptr,
const char *propname, Error **errp)
{
BlockBackend *blk;
bool blk_created = false;
int ret;
blk = blk_by_name(str);
if (!blk) {
BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL);
if (bs) {
blk = blk_new(0, BLK_PERM_ALL);
blk_created = true;
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
goto fail;
}
}
}
if (!blk) {
error_setg(errp, "Property '%s.%s' can't find value '%s'",
object_get_typename(OBJECT(dev)), propname, str);
goto fail;
}
if (blk_attach_dev(blk, dev) < 0) {
DriveInfo *dinfo = blk_legacy_dinfo(blk);
if (dinfo && dinfo->type != IF_NONE) {
error_setg(errp, "Drive '%s' is already in use because "
"it has been automatically connected to another "
"device (did you need 'if=none' in the drive options?)",
str);
} else {
error_setg(errp, "Drive '%s' is already in use by another device",
str);
}
goto fail;
}
*ptr = blk;
fail:
if (blk_created) {
/* If we need to keep a reference, blk_attach_dev() took it */
blk_unref(blk);
}
}
static void release_drive(Object *obj, const char *name, void *opaque)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
BlockBackend **ptr = qdev_get_prop_ptr(dev, prop);
if (*ptr) {
AioContext *ctx = blk_get_aio_context(*ptr);
aio_context_acquire(ctx);
blockdev_auto_del(*ptr);
blk_detach_dev(*ptr, dev);
aio_context_release(ctx);
}
}
static char *print_drive(void *ptr)
{
const char *name;
name = blk_name(ptr);
if (!*name) {
BlockDriverState *bs = blk_bs(ptr);
if (bs) {
name = bdrv_get_node_name(bs);
}
}
return g_strdup(name);
}
static void get_drive(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
get_pointer(obj, v, opaque, print_drive, name, errp);
}
static void set_drive(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
set_pointer(obj, v, opaque, parse_drive, name, errp);
}
PropertyInfo qdev_prop_drive = {
.name = "str",
.description = "Node name or ID of a block device to use as a backend",
.get = get_drive,
.set = set_drive,
.release = release_drive,
};
/* --- character device --- */
static void get_chr(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
DeviceState *dev = DEVICE(obj);
CharBackend *be = qdev_get_prop_ptr(dev, opaque);
char *p;
p = g_strdup(be->chr && be->chr->label ? be->chr->label : "");
visit_type_str(v, name, &p, errp);
g_free(p);
}
static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
DeviceState *dev = DEVICE(obj);
Error *local_err = NULL;
Property *prop = opaque;
CharBackend *be = qdev_get_prop_ptr(dev, prop);
Chardev *s;
char *str;
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;
}
if (!*str) {
g_free(str);
be->chr = NULL;
return;
}
s = qemu_chr_find(str);
if (s == NULL) {
error_setg(errp, "Property '%s.%s' can't find value '%s'",
object_get_typename(obj), prop->name, str);
} else if (!qemu_chr_fe_init(be, s, errp)) {
error_prepend(errp, "Property '%s.%s' can't take value '%s': ",
object_get_typename(obj), prop->name, str);
}
g_free(str);
}
static void release_chr(Object *obj, const char *name, void *opaque)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
CharBackend *be = qdev_get_prop_ptr(dev, prop);
qemu_chr_fe_deinit(be);
}
PropertyInfo qdev_prop_chr = {
.name = "str",
.description = "ID of a chardev to use as a backend",
.get = get_chr,
.set = set_chr,
.release = release_chr,
};
/* --- netdev device --- */
static void get_netdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
NICPeers *peers_ptr = qdev_get_prop_ptr(dev, prop);
char *p = g_strdup(peers_ptr->ncs[0] ? peers_ptr->ncs[0]->name : "");
visit_type_str(v, name, &p, errp);
g_free(p);
}
static void set_netdev(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
NICPeers *peers_ptr = qdev_get_prop_ptr(dev, prop);
NetClientState **ncs = peers_ptr->ncs;
NetClientState *peers[MAX_QUEUE_NUM];
Error *local_err = NULL;
int queues, err = 0, i = 0;
char *str;
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;
}
queues = qemu_find_net_clients_except(str, peers,
NET_CLIENT_DRIVER_NIC,
MAX_QUEUE_NUM);
if (queues == 0) {
err = -ENOENT;
goto out;
}
if (queues > MAX_QUEUE_NUM) {
error_setg(errp, "queues of backend '%s'(%d) exceeds QEMU limitation(%d)",
str, queues, MAX_QUEUE_NUM);
goto out;
}
for (i = 0; i < queues; i++) {
if (peers[i] == NULL) {
err = -ENOENT;
goto out;
}
if (peers[i]->peer) {
err = -EEXIST;
goto out;
}
if (ncs[i]) {
err = -EINVAL;
goto out;
}
ncs[i] = peers[i];
ncs[i]->queue_index = i;
}
peers_ptr->queues = queues;
out:
error_set_from_qdev_prop_error(errp, err, dev, prop, str);
g_free(str);
}
PropertyInfo qdev_prop_netdev = {
.name = "str",
.description = "ID of a netdev to use as a backend",
.get = get_netdev,
.set = set_netdev,
};
/* --- vlan --- */
static int print_vlan(DeviceState *dev, Property *prop, char *dest, size_t len)
{
NetClientState **ptr = qdev_get_prop_ptr(dev, prop);
if (*ptr) {
int id;
if (!net_hub_id_for_client(*ptr, &id)) {
return snprintf(dest, len, "%d", id);
}
}
return snprintf(dest, len, "<null>");
}
static void get_vlan(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
NetClientState **ptr = qdev_get_prop_ptr(dev, prop);
int32_t id = -1;
if (*ptr) {
int hub_id;
if (!net_hub_id_for_client(*ptr, &hub_id)) {
id = hub_id;
}
}
visit_type_int32(v, name, &id, errp);
}
static void set_vlan(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
DeviceState *dev = DEVICE(obj);
Property *prop = opaque;
NICPeers *peers_ptr = qdev_get_prop_ptr(dev, prop);
NetClientState **ptr = &peers_ptr->ncs[0];
Error *local_err = NULL;
int32_t id;
NetClientState *hubport;
if (dev->realized) {
qdev_prop_set_after_realize(dev, name, errp);
return;
}
visit_type_int32(v, name, &id, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
if (id == -1) {
*ptr = NULL;
return;
}
if (*ptr) {
error_set_from_qdev_prop_error(errp, -EINVAL, dev, prop, name);
return;
}
hubport = net_hub_port_find(id);
if (!hubport) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
name, prop->info->name);
return;
}
*ptr = hubport;
}
PropertyInfo qdev_prop_vlan = {
.name = "int32",
.description = "Integer VLAN id to connect to",
.print = print_vlan,
.get = get_vlan,
.set = set_vlan,
};
void qdev_prop_set_drive(DeviceState *dev, const char *name,
BlockBackend *value, Error **errp)
{
const char *ref = "";
if (value) {
ref = blk_name(value);
if (!*ref) {
BlockDriverState *bs = blk_bs(value);
if (bs) {
ref = bdrv_get_node_name(bs);
}
}
}
object_property_set_str(OBJECT(dev), ref, name, errp);
}
void qdev_prop_set_chr(DeviceState *dev, const char *name,
Chardev *value)
{
assert(!value || value->label);
object_property_set_str(OBJECT(dev),
value ? value->label : "", name, &error_abort);
}
void qdev_prop_set_netdev(DeviceState *dev, const char *name,
NetClientState *value)
{
assert(!value || value->name);
object_property_set_str(OBJECT(dev),
value ? value->name : "", name, &error_abort);
}
void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd)
{
qdev_prop_set_macaddr(dev, "mac", nd->macaddr.a);
if (nd->netdev) {
qdev_prop_set_netdev(dev, "netdev", nd->netdev);
}
if (nd->nvectors != DEV_NVECTORS_UNSPECIFIED &&
object_property_find(OBJECT(dev), "vectors", NULL)) {
qdev_prop_set_uint32(dev, "vectors", nd->nvectors);
}
nd->instantiated = 1;
}