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004e95df98
qemu/blockjob.c
Kevin Wolf 004e95df98 job: Convert block_job_cancel_async() to Job 
block_job_cancel_async() did two things that were still block job
specific:

* Setting job->force. This field makes sense on the Job level, so we can
  just move it. While at it, rename it to job->force_cancel to make its
  purpose more obvious.

* Resetting the I/O status. This can't be moved because generic Jobs
  don't have an I/O status. What the function really implements is a
  user resume, except without entering the coroutine. Consequently, it
  makes sense to call the .user_resume driver callback here which
  already resets the I/O status.

  The old block_job_cancel_async() has two separate if statements that
  check job->iostatus != BLOCK_DEVICE_IO_STATUS_OK and job->user_paused.
  However, the former condition always implies the latter (as is
  asserted in block_job_iostatus_reset()), so changing the explicit call
  of block_job_iostatus_reset() on the former condition with the
  .user_resume callback on the latter condition is equivalent and
  doesn't need to access any BlockJob specific state.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2018-05-23 14:30:50 +02:00

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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 "qemu/osdep.h"
#include "qemu-common.h"
#include "block/block.h"
#include "block/blockjob_int.h"
#include "block/block_int.h"
#include "block/trace.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "qapi/qapi-events-block-core.h"
#include "qapi/qmp/qerror.h"
#include "qemu/coroutine.h"
#include "qemu/timer.h"
/* Transactional group of block jobs */
struct BlockJobTxn {
/* Is this txn being cancelled? */
bool aborting;
/* List of jobs */
QLIST_HEAD(, BlockJob) jobs;
/* Reference count */
int refcnt;
};
/*
* The block job API is composed of two categories of functions.
*
* The first includes functions used by the monitor. The monitor is
* peculiar in that it accesses the block job list with block_job_get, and
* therefore needs consistency across block_job_get and the actual operation
* (e.g. block_job_set_speed). The consistency is achieved with
* aio_context_acquire/release. These functions are declared in blockjob.h.
*
* The second includes functions used by the block job drivers and sometimes
* by the core block layer. These do not care about locking, because the
* whole coroutine runs under the AioContext lock, and are declared in
* blockjob_int.h.
*/
static bool is_block_job(Job *job)
{
return job_type(job) == JOB_TYPE_BACKUP ||
job_type(job) == JOB_TYPE_COMMIT ||
job_type(job) == JOB_TYPE_MIRROR ||
job_type(job) == JOB_TYPE_STREAM;
}
BlockJob *block_job_next(BlockJob *bjob)
{
Job *job = bjob ? &bjob->job : NULL;
do {
job = job_next(job);
} while (job && !is_block_job(job));
return job ? container_of(job, BlockJob, job) : NULL;
}
BlockJob *block_job_get(const char *id)
{
Job *job = job_get(id);
if (job && is_block_job(job)) {
return container_of(job, BlockJob, job);
} else {
return NULL;
}
}
BlockJobTxn *block_job_txn_new(void)
{
BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
QLIST_INIT(&txn->jobs);
txn->refcnt = 1;
return txn;
}
static void block_job_txn_ref(BlockJobTxn *txn)
{
txn->refcnt++;
}
void block_job_txn_unref(BlockJobTxn *txn)
{
if (txn && --txn->refcnt == 0) {
g_free(txn);
}
}
void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
{
if (!txn) {
return;
}
assert(!job->txn);
job->txn = txn;
QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
block_job_txn_ref(txn);
}
void block_job_txn_del_job(BlockJob *job)
{
if (job->txn) {
QLIST_REMOVE(job, txn_list);
block_job_txn_unref(job->txn);
job->txn = NULL;
}
}
static void block_job_attached_aio_context(AioContext *new_context,
void *opaque);
static void block_job_detach_aio_context(void *opaque);
void block_job_free(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
BlockDriverState *bs = blk_bs(bjob->blk);
assert(!bjob->txn);
bs->job = NULL;
block_job_remove_all_bdrv(bjob);
blk_remove_aio_context_notifier(bjob->blk,
block_job_attached_aio_context,
block_job_detach_aio_context, bjob);
blk_unref(bjob->blk);
error_free(bjob->blocker);
}
static void block_job_attached_aio_context(AioContext *new_context,
void *opaque)
{
BlockJob *job = opaque;
job->job.aio_context = new_context;
if (job->driver->attached_aio_context) {
job->driver->attached_aio_context(job, new_context);
}
job_resume(&job->job);
}
static void block_job_drain(BlockJob *job)
{
/* If job is !job->job.busy this kicks it into the next pause point. */
block_job_enter(job);
blk_drain(job->blk);
if (job->driver->drain) {
job->driver->drain(job);
}
}
static void block_job_detach_aio_context(void *opaque)
{
BlockJob *job = opaque;
/* In case the job terminates during aio_poll()... */
job_ref(&job->job);
job_pause(&job->job);
while (!job->job.paused && !job_is_completed(&job->job)) {
block_job_drain(job);
}
job->job.aio_context = NULL;
job_unref(&job->job);
}
static char *child_job_get_parent_desc(BdrvChild *c)
{
BlockJob *job = c->opaque;
return g_strdup_printf("%s job '%s'", job_type_str(&job->job), job->job.id);
}
static void child_job_drained_begin(BdrvChild *c)
{
BlockJob *job = c->opaque;
job_pause(&job->job);
}
static void child_job_drained_end(BdrvChild *c)
{
BlockJob *job = c->opaque;
job_resume(&job->job);
}
static const BdrvChildRole child_job = {
.get_parent_desc = child_job_get_parent_desc,
.drained_begin = child_job_drained_begin,
.drained_end = child_job_drained_end,
.stay_at_node = true,
};
void block_job_remove_all_bdrv(BlockJob *job)
{
GSList *l;
for (l = job->nodes; l; l = l->next) {
BdrvChild *c = l->data;
bdrv_op_unblock_all(c->bs, job->blocker);
bdrv_root_unref_child(c);
}
g_slist_free(job->nodes);
job->nodes = NULL;
}
int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
uint64_t perm, uint64_t shared_perm, Error **errp)
{
BdrvChild *c;
c = bdrv_root_attach_child(bs, name, &child_job, perm, shared_perm,
job, errp);
if (c == NULL) {
return -EPERM;
}
job->nodes = g_slist_prepend(job->nodes, c);
bdrv_ref(bs);
bdrv_op_block_all(bs, job->blocker);
return 0;
}
bool block_job_is_internal(BlockJob *job)
{
return (job->job.id == NULL);
}
const BlockJobDriver *block_job_driver(BlockJob *job)
{
return job->driver;
}
static int block_job_prepare(BlockJob *job)
{
if (job->job.ret == 0 && job->driver->prepare) {
job->job.ret = job->driver->prepare(job);
}
return job->job.ret;
}
static void job_cancel_async(Job *job, bool force)
{
if (job->user_paused) {
/* Do not call job_enter here, the caller will handle it. */
job->user_paused = false;
if (job->driver->user_resume) {
job->driver->user_resume(job);
}
assert(job->pause_count > 0);
job->pause_count--;
}
job->cancelled = true;
/* To prevent 'force == false' overriding a previous 'force == true' */
job->force_cancel |= force;
}
static int block_job_txn_apply(BlockJobTxn *txn, int fn(BlockJob *), bool lock)
{
AioContext *ctx;
BlockJob *job, *next;
int rc = 0;
QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) {
if (lock) {
ctx = blk_get_aio_context(job->blk);
aio_context_acquire(ctx);
}
rc = fn(job);
if (lock) {
aio_context_release(ctx);
}
if (rc) {
break;
}
}
return rc;
}
static int block_job_finish_sync(BlockJob *job,
void (*finish)(BlockJob *, Error **errp),
Error **errp)
{
Error *local_err = NULL;
int ret;
assert(blk_bs(job->blk)->job == job);
job_ref(&job->job);
if (finish) {
finish(job, &local_err);
}
if (local_err) {
error_propagate(errp, local_err);
job_unref(&job->job);
return -EBUSY;
}
/* block_job_drain calls block_job_enter, and it should be enough to
* induce progress until the job completes or moves to the main thread.
*/
while (!job->job.deferred_to_main_loop && !job_is_completed(&job->job)) {
block_job_drain(job);
}
while (!job_is_completed(&job->job)) {
aio_poll(qemu_get_aio_context(), true);
}
ret = (job_is_cancelled(&job->job) && job->job.ret == 0)
? -ECANCELED : job->job.ret;
job_unref(&job->job);
return ret;
}
static void block_job_completed_txn_abort(BlockJob *job)
{
AioContext *ctx;
BlockJobTxn *txn = job->txn;
BlockJob *other_job;
if (txn->aborting) {
/*
* We are cancelled by another job, which will handle everything.
*/
return;
}
txn->aborting = true;
block_job_txn_ref(txn);
/* We are the first failed job. Cancel other jobs. */
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
ctx = blk_get_aio_context(other_job->blk);
aio_context_acquire(ctx);
}
/* Other jobs are effectively cancelled by us, set the status for
* them; this job, however, may or may not be cancelled, depending
* on the caller, so leave it. */
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (other_job != job) {
job_cancel_async(&other_job->job, false);
}
}
while (!QLIST_EMPTY(&txn->jobs)) {
other_job = QLIST_FIRST(&txn->jobs);
ctx = blk_get_aio_context(other_job->blk);
if (!job_is_completed(&other_job->job)) {
assert(job_is_cancelled(&other_job->job));
block_job_finish_sync(other_job, NULL, NULL);
}
job_finalize_single(&other_job->job);
aio_context_release(ctx);
}
block_job_txn_unref(txn);
}
static int block_job_needs_finalize(BlockJob *job)
{
return !job->job.auto_finalize;
}
static int block_job_finalize_single(BlockJob *job)
{
return job_finalize_single(&job->job);
}
static void block_job_do_finalize(BlockJob *job)
{
int rc;
assert(job && job->txn);
/* prepare the transaction to complete */
rc = block_job_txn_apply(job->txn, block_job_prepare, true);
if (rc) {
block_job_completed_txn_abort(job);
} else {
block_job_txn_apply(job->txn, block_job_finalize_single, true);
}
}
static int block_job_transition_to_pending(BlockJob *job)
{
job_state_transition(&job->job, JOB_STATUS_PENDING);
if (!job->job.auto_finalize) {
job_event_pending(&job->job);
}
return 0;
}
static void block_job_completed_txn_success(BlockJob *job)
{
BlockJobTxn *txn = job->txn;
BlockJob *other_job;
job_state_transition(&job->job, JOB_STATUS_WAITING);
/*
* Successful completion, see if there are other running jobs in this
* txn.
*/
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (!job_is_completed(&other_job->job)) {
return;
}
assert(other_job->job.ret == 0);
}
block_job_txn_apply(txn, block_job_transition_to_pending, false);
/* If no jobs need manual finalization, automatically do so */
if (block_job_txn_apply(txn, block_job_needs_finalize, false) == 0) {
block_job_do_finalize(job);
}
}
/* Assumes the job_mutex is held */
static bool job_timer_pending(Job *job)
{
return timer_pending(&job->sleep_timer);
}
void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
{
int64_t old_speed = job->speed;
if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp)) {
return;
}
if (speed < 0) {
error_setg(errp, QERR_INVALID_PARAMETER, "speed");
return;
}
ratelimit_set_speed(&job->limit, speed, BLOCK_JOB_SLICE_TIME);
job->speed = speed;
if (speed && speed <= old_speed) {
return;
}
/* kick only if a timer is pending */
job_enter_cond(&job->job, job_timer_pending);
}
int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n)
{
if (!job->speed) {
return 0;
}
return ratelimit_calculate_delay(&job->limit, n);
}
void block_job_complete(BlockJob *job, Error **errp)
{
/* Should not be reachable via external interface for internal jobs */
assert(job->job.id);
if (job_apply_verb(&job->job, JOB_VERB_COMPLETE, errp)) {
return;
}
if (job->job.pause_count || job_is_cancelled(&job->job) ||
!job->driver->complete)
{
error_setg(errp, "The active block job '%s' cannot be completed",
job->job.id);
return;
}
job->driver->complete(job, errp);
}
void block_job_finalize(BlockJob *job, Error **errp)
{
assert(job && job->job.id);
if (job_apply_verb(&job->job, JOB_VERB_FINALIZE, errp)) {
return;
}
block_job_do_finalize(job);
}
void block_job_dismiss(BlockJob **jobptr, Error **errp)
{
BlockJob *job = *jobptr;
/* similarly to _complete, this is QMP-interface only. */
assert(job->job.id);
if (job_apply_verb(&job->job, JOB_VERB_DISMISS, errp)) {
return;
}
job_do_dismiss(&job->job);
*jobptr = NULL;
}
void block_job_cancel(BlockJob *job, bool force)
{
if (job->job.status == JOB_STATUS_CONCLUDED) {
job_do_dismiss(&job->job);
return;
}
job_cancel_async(&job->job, force);
if (!job_started(&job->job)) {
block_job_completed(job, -ECANCELED);
} else if (job->job.deferred_to_main_loop) {
block_job_completed_txn_abort(job);
} else {
block_job_enter(job);
}
}
void block_job_user_cancel(BlockJob *job, bool force, Error **errp)
{
if (job_apply_verb(&job->job, JOB_VERB_CANCEL, errp)) {
return;
}
block_job_cancel(job, force);
}
/* 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, false);
}
int block_job_cancel_sync(BlockJob *job)
{
return block_job_finish_sync(job, &block_job_cancel_err, NULL);
}
void block_job_cancel_sync_all(void)
{
BlockJob *job;
AioContext *aio_context;
while ((job = block_job_next(NULL))) {
aio_context = blk_get_aio_context(job->blk);
aio_context_acquire(aio_context);
block_job_cancel_sync(job);
aio_context_release(aio_context);
}
}
int block_job_complete_sync(BlockJob *job, Error **errp)
{
return block_job_finish_sync(job, &block_job_complete, errp);
}
void block_job_progress_update(BlockJob *job, uint64_t done)
{
job->offset += done;
}
void block_job_progress_set_remaining(BlockJob *job, uint64_t remaining)
{
job->len = job->offset + remaining;
}
BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
{
BlockJobInfo *info;
if (block_job_is_internal(job)) {
error_setg(errp, "Cannot query QEMU internal jobs");
return NULL;
}
info = g_new0(BlockJobInfo, 1);
info->type = g_strdup(job_type_str(&job->job));
info->device = g_strdup(job->job.id);
info->len = job->len;
info->busy = atomic_read(&job->job.busy);
info->paused = job->job.pause_count > 0;
info->offset = job->offset;
info->speed = job->speed;
info->io_status = job->iostatus;
info->ready = job->ready;
info->status = job->job.status;
info->auto_finalize = job->job.auto_finalize;
info->auto_dismiss = job->job.auto_dismiss;
info->has_error = job->job.ret != 0;
info->error = job->job.ret ? g_strdup(strerror(-job->job.ret)) : NULL;
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;
}
}
static void block_job_event_cancelled(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
if (block_job_is_internal(job)) {
return;
}
qapi_event_send_block_job_cancelled(job_type(&job->job),
job->job.id,
job->len,
job->offset,
job->speed,
&error_abort);
}
static void block_job_event_completed(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
const char *msg = NULL;
if (block_job_is_internal(job)) {
return;
}
if (job->job.ret < 0) {
msg = strerror(-job->job.ret);
}
qapi_event_send_block_job_completed(job_type(&job->job),
job->job.id,
job->len,
job->offset,
job->speed,
!!msg,
msg,
&error_abort);
}
static void block_job_event_pending(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
if (block_job_is_internal(job)) {
return;
}
qapi_event_send_block_job_pending(job_type(&job->job),
job->job.id,
&error_abort);
}
/*
* API for block job drivers and the block layer. These functions are
* declared in blockjob_int.h.
*/
void *block_job_create(const char *job_id, const BlockJobDriver *driver,
BlockJobTxn *txn, BlockDriverState *bs, uint64_t perm,
uint64_t shared_perm, int64_t speed, int flags,
BlockCompletionFunc *cb, void *opaque, Error **errp)
{
BlockBackend *blk;
BlockJob *job;
int ret;
if (bs->job) {
error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
return NULL;
}
if (job_id == NULL && !(flags & JOB_INTERNAL)) {
job_id = bdrv_get_device_name(bs);
}
blk = blk_new(perm, shared_perm);
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
blk_unref(blk);
return NULL;
}
job = job_create(job_id, &driver->job_driver, blk_get_aio_context(blk),
flags, cb, opaque, errp);
if (job == NULL) {
blk_unref(blk);
return NULL;
}
assert(is_block_job(&job->job));
assert(job->job.driver->free == &block_job_free);
assert(job->job.driver->user_resume == &block_job_user_resume);
job->driver = driver;
job->blk = blk;
job->finalize_cancelled_notifier.notify = block_job_event_cancelled;
job->finalize_completed_notifier.notify = block_job_event_completed;
job->pending_notifier.notify = block_job_event_pending;
notifier_list_add(&job->job.on_finalize_cancelled,
&job->finalize_cancelled_notifier);
notifier_list_add(&job->job.on_finalize_completed,
&job->finalize_completed_notifier);
notifier_list_add(&job->job.on_pending, &job->pending_notifier);
error_setg(&job->blocker, "block device is in use by block job: %s",
job_type_str(&job->job));
block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
bs->job = job;
bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
block_job_detach_aio_context, 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) {
job_early_fail(&job->job);
error_propagate(errp, local_err);
return NULL;
}
}
/* Single jobs are modeled as single-job transactions for sake of
* consolidating the job management logic */
if (!txn) {
txn = block_job_txn_new();
block_job_txn_add_job(txn, job);
block_job_txn_unref(txn);
} else {
block_job_txn_add_job(txn, job);
}
return job;
}
void block_job_completed(BlockJob *job, int ret)
{
assert(job && job->txn && !job_is_completed(&job->job));
assert(blk_bs(job->blk)->job == job);
job->job.ret = ret;
job_update_rc(&job->job);
trace_block_job_completed(job, ret, job->job.ret);
if (job->job.ret) {
block_job_completed_txn_abort(job);
} else {
block_job_completed_txn_success(job);
}
}
void block_job_enter(BlockJob *job)
{
job_enter_cond(&job->job, NULL);
}
void block_job_yield(BlockJob *job)
{
assert(job->job.busy);
/* Check cancellation *before* setting busy = false, too! */
if (job_is_cancelled(&job->job)) {
return;
}
if (!job_should_pause(&job->job)) {
job_do_yield(&job->job, -1);
}
job_pause_point(&job->job);
}
void block_job_iostatus_reset(BlockJob *job)
{
if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
return;
}
assert(job->job.user_paused && job->job.pause_count > 0);
job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
}
void block_job_user_resume(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
block_job_iostatus_reset(bjob);
}
void block_job_event_ready(BlockJob *job)
{
job_state_transition(&job->job, JOB_STATUS_READY);
job->ready = true;
if (block_job_is_internal(job)) {
return;
}
qapi_event_send_block_job_ready(job_type(&job->job),
job->job.id,
job->len,
job->offset,
job->speed, &error_abort);
}
BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
int is_read, int error)
{
BlockErrorAction action;
switch (on_err) {
case BLOCKDEV_ON_ERROR_ENOSPC:
case BLOCKDEV_ON_ERROR_AUTO:
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();
}
if (!block_job_is_internal(job)) {
qapi_event_send_block_job_error(job->job.id,
is_read ? IO_OPERATION_TYPE_READ :
IO_OPERATION_TYPE_WRITE,
action, &error_abort);
}
if (action == BLOCK_ERROR_ACTION_STOP) {
job_pause(&job->job);
/* make the pause user visible, which will be resumed from QMP. */
job->job.user_paused = true;
block_job_iostatus_set_err(job, error);
}
return action;
}
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