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QEMU-Nyx-fork/blockjob.c
Stefan Hajnoczi b112a65c52 block: declare blockjobs and dataplane friends! 
Now that blockjobs use AioContext they are safe for use with dataplane.
Unblock them!

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1413889440-32577-12-git-send-email-stefanha@redhat.com
2014-11-03 11:41:49 +00:00

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/*
* QEMU System Emulator block driver
*
* Copyright (c) 2011 IBM Corp.
* Copyright (c) 2012 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "config-host.h"
#include "qemu-common.h"
#include "trace.h"
#include "block/block.h"
#include "block/blockjob.h"
#include "block/block_int.h"
#include "qapi/qmp/qjson.h"
#include "block/coroutine.h"
#include "qmp-commands.h"
#include "qemu/timer.h"
#include "qapi-event.h"
void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
int64_t speed, BlockCompletionFunc *cb,
void *opaque, Error **errp)
{
BlockJob *job;
if (bs->job) {
error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
return NULL;
}
bdrv_ref(bs);
job = g_malloc0(driver->instance_size);
error_setg(&job->blocker, "block device is in use by block job: %s",
BlockJobType_lookup[driver->job_type]);
bdrv_op_block_all(bs, job->blocker);
bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
job->driver = driver;
job->bs = bs;
job->cb = cb;
job->opaque = opaque;
job->busy = true;
bs->job = job;
/* Only set speed when necessary to avoid NotSupported error */
if (speed != 0) {
Error *local_err = NULL;
block_job_set_speed(job, speed, &local_err);
if (local_err) {
bs->job = NULL;
bdrv_op_unblock_all(bs, job->blocker);
error_free(job->blocker);
g_free(job);
error_propagate(errp, local_err);
return NULL;
}
}
return job;
}
void block_job_completed(BlockJob *job, int ret)
{
BlockDriverState *bs = job->bs;
assert(bs->job == job);
job->cb(job->opaque, ret);
bs->job = NULL;
bdrv_op_unblock_all(bs, job->blocker);
error_free(job->blocker);
g_free(job);
}
void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
{
Error *local_err = NULL;
if (!job->driver->set_speed) {
error_set(errp, QERR_UNSUPPORTED);
return;
}
job->driver->set_speed(job, speed, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
job->speed = speed;
}
void block_job_complete(BlockJob *job, Error **errp)
{
if (job->paused || job->cancelled || !job->driver->complete) {
error_set(errp, QERR_BLOCK_JOB_NOT_READY,
bdrv_get_device_name(job->bs));
return;
}
job->driver->complete(job, errp);
}
void block_job_pause(BlockJob *job)
{
job->paused = true;
}
bool block_job_is_paused(BlockJob *job)
{
return job->paused;
}
void block_job_resume(BlockJob *job)
{
job->paused = false;
block_job_iostatus_reset(job);
if (job->co && !job->busy) {
qemu_coroutine_enter(job->co, NULL);
}
}
void block_job_cancel(BlockJob *job)
{
job->cancelled = true;
block_job_resume(job);
}
bool block_job_is_cancelled(BlockJob *job)
{
return job->cancelled;
}
void block_job_iostatus_reset(BlockJob *job)
{
job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
if (job->driver->iostatus_reset) {
job->driver->iostatus_reset(job);
}
}
struct BlockFinishData {
BlockJob *job;
BlockCompletionFunc *cb;
void *opaque;
bool cancelled;
int ret;
};
static void block_job_finish_cb(void *opaque, int ret)
{
struct BlockFinishData *data = opaque;
data->cancelled = block_job_is_cancelled(data->job);
data->ret = ret;
data->cb(data->opaque, ret);
}
static int block_job_finish_sync(BlockJob *job,
void (*finish)(BlockJob *, Error **errp),
Error **errp)
{
struct BlockFinishData data;
BlockDriverState *bs = job->bs;
Error *local_err = NULL;
assert(bs->job == job);
/* Set up our own callback to store the result and chain to
* the original callback.
*/
data.job = job;
data.cb = job->cb;
data.opaque = job->opaque;
data.ret = -EINPROGRESS;
job->cb = block_job_finish_cb;
job->opaque = &data;
finish(job, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return -EBUSY;
}
while (data.ret == -EINPROGRESS) {
aio_poll(bdrv_get_aio_context(bs), true);
}
return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
}
/* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
* used with block_job_finish_sync() without the need for (rather nasty)
* function pointer casts there. */
static void block_job_cancel_err(BlockJob *job, Error **errp)
{
block_job_cancel(job);
}
int block_job_cancel_sync(BlockJob *job)
{
return block_job_finish_sync(job, &block_job_cancel_err, NULL);
}
int block_job_complete_sync(BlockJob *job, Error **errp)
{
return block_job_finish_sync(job, &block_job_complete, errp);
}
void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
{
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
if (block_job_is_cancelled(job)) {
return;
}
job->busy = false;
if (block_job_is_paused(job)) {
qemu_coroutine_yield();
} else {
co_aio_sleep_ns(bdrv_get_aio_context(job->bs), type, ns);
}
job->busy = true;
}
void block_job_yield(BlockJob *job)
{
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
if (block_job_is_cancelled(job)) {
return;
}
job->busy = false;
qemu_coroutine_yield();
job->busy = true;
}
BlockJobInfo *block_job_query(BlockJob *job)
{
BlockJobInfo *info = g_new0(BlockJobInfo, 1);
info->type = g_strdup(BlockJobType_lookup[job->driver->job_type]);
info->device = g_strdup(bdrv_get_device_name(job->bs));
info->len = job->len;
info->busy = job->busy;
info->paused = job->paused;
info->offset = job->offset;
info->speed = job->speed;
info->io_status = job->iostatus;
info->ready = job->ready;
return info;
}
static void block_job_iostatus_set_err(BlockJob *job, int error)
{
if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
BLOCK_DEVICE_IO_STATUS_FAILED;
}
}
void block_job_event_cancelled(BlockJob *job)
{
qapi_event_send_block_job_cancelled(job->driver->job_type,
bdrv_get_device_name(job->bs),
job->len,
job->offset,
job->speed,
&error_abort);
}
void block_job_event_completed(BlockJob *job, const char *msg)
{
qapi_event_send_block_job_completed(job->driver->job_type,
bdrv_get_device_name(job->bs),
job->len,
job->offset,
job->speed,
!!msg,
msg,
&error_abort);
}
void block_job_event_ready(BlockJob *job)
{
job->ready = true;
qapi_event_send_block_job_ready(job->driver->job_type,
bdrv_get_device_name(job->bs),
job->len,
job->offset,
job->speed, &error_abort);
}
BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
BlockdevOnError on_err,
int is_read, int error)
{
BlockErrorAction action;
switch (on_err) {
case BLOCKDEV_ON_ERROR_ENOSPC:
action = (error == ENOSPC) ?
BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
break;
case BLOCKDEV_ON_ERROR_STOP:
action = BLOCK_ERROR_ACTION_STOP;
break;
case BLOCKDEV_ON_ERROR_REPORT:
action = BLOCK_ERROR_ACTION_REPORT;
break;
case BLOCKDEV_ON_ERROR_IGNORE:
action = BLOCK_ERROR_ACTION_IGNORE;
break;
default:
abort();
}
qapi_event_send_block_job_error(bdrv_get_device_name(job->bs),
is_read ? IO_OPERATION_TYPE_READ :
IO_OPERATION_TYPE_WRITE,
action, &error_abort);
if (action == BLOCK_ERROR_ACTION_STOP) {
block_job_pause(job);
block_job_iostatus_set_err(job, error);
if (bs != job->bs) {
bdrv_iostatus_set_err(bs, error);
}
}
return action;
}
typedef struct {
BlockJob *job;
QEMUBH *bh;
AioContext *aio_context;
BlockJobDeferToMainLoopFn *fn;
void *opaque;
} BlockJobDeferToMainLoopData;
static void block_job_defer_to_main_loop_bh(void *opaque)
{
BlockJobDeferToMainLoopData *data = opaque;
AioContext *aio_context;
qemu_bh_delete(data->bh);
/* Prevent race with block_job_defer_to_main_loop() */
aio_context_acquire(data->aio_context);
/* Fetch BDS AioContext again, in case it has changed */
aio_context = bdrv_get_aio_context(data->job->bs);
aio_context_acquire(aio_context);
data->fn(data->job, data->opaque);
aio_context_release(aio_context);
aio_context_release(data->aio_context);
g_free(data);
}
void block_job_defer_to_main_loop(BlockJob *job,
BlockJobDeferToMainLoopFn *fn,
void *opaque)
{
BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
data->job = job;
data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
data->aio_context = bdrv_get_aio_context(job->bs);
data->fn = fn;
data->opaque = opaque;
qemu_bh_schedule(data->bh);
}
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