Commit e5ab4347 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block/create: Make x-blockdev-create a job 



This changes the x-blockdev-create QMP command so that it doesn't block
the monitor and the main loop any more, but starts a background job that
performs the image creation.

The basic job as implemented here is all that is necessary to make image
creation asynchronous and to provide a QMP interface that can be marked
stable, but it still lacks a few features that jobs usually provide: The
job will ignore pause commands and it doesn't publish more than very
basic progress yet (total-progress is 1 and current-progress advances
from 0 to 1 when the driver callbacks returns). These features can be
added later without breaking compatibility.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
parent 1266c9b9

block/create.c

+46 −21
Original line number Diff line number Diff line
@@ -24,28 +24,51 @@ 


#include "qemu/osdep.h"

#include "block/block_int.h"

#include "qemu/job.h"

#include "qapi/qapi-commands-block-core.h"

#include "qapi/qapi-visit-block-core.h"

#include "qapi/clone-visitor.h"

#include "qapi/error.h"



typedef struct BlockdevCreateCo {

typedef struct BlockdevCreateJob {

    Job common;

    BlockDriver *drv;

    BlockdevCreateOptions *opts;

    int ret;

    Error **errp;

} BlockdevCreateCo;

    Error *err;

} BlockdevCreateJob;



static void coroutine_fn bdrv_co_create_co_entry(void *opaque)

static void blockdev_create_complete(Job *job, void *opaque)

{

    BlockdevCreateCo *cco = opaque;

    cco->ret = cco->drv->bdrv_co_create(cco->opts, cco->errp);

    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);



    job_completed(job, s->ret, s->err);

}



void qmp_x_blockdev_create(BlockdevCreateOptions *options, Error **errp)

static void coroutine_fn blockdev_create_run(void *opaque)

{

    BlockdevCreateJob *s = opaque;



    job_progress_set_remaining(&s->common, 1);

    s->ret = s->drv->bdrv_co_create(s->opts, &s->err);

    job_progress_update(&s->common, 1);



    qapi_free_BlockdevCreateOptions(s->opts);

    job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);

}



static const JobDriver blockdev_create_job_driver = {

    .instance_size = sizeof(BlockdevCreateJob),

    .job_type      = JOB_TYPE_CREATE,

    .start         = blockdev_create_run,

};



void qmp_x_blockdev_create(const char *job_id, BlockdevCreateOptions *options,

                           Error **errp)

{

    BlockdevCreateJob *s;

    const char *fmt = BlockdevDriver_str(options->driver);

    BlockDriver *drv = bdrv_find_format(fmt);

    Coroutine *co;

    BlockdevCreateCo cco;



    /* If the driver is in the schema, we know that it exists. But it may not

     * be whitelisted. */
@@ -55,22 +78,24 @@ void qmp_x_blockdev_create(BlockdevCreateOptions *options, Error **errp) 
        return;

    }



    /* Call callback if it exists */

    /* Error out if the driver doesn't support .bdrv_co_create */

    if (!drv->bdrv_co_create) {

        error_setg(errp, "Driver does not support blockdev-create");

        return;

    }



    cco = (BlockdevCreateCo) {

        .drv = drv,

        .opts = options,

        .ret = -EINPROGRESS,

        .errp = errp,

    };



    co = qemu_coroutine_create(bdrv_co_create_co_entry, &cco);

    qemu_coroutine_enter(co);

    while (cco.ret == -EINPROGRESS) {

        aio_poll(qemu_get_aio_context(), true);

    /* Create the block job */

    /* TODO Running in the main context. Block drivers need to error out or add

     * locking when they use a BDS in a different AioContext. */

    s = job_create(job_id, &blockdev_create_job_driver, NULL,

                   qemu_get_aio_context(), JOB_DEFAULT | JOB_MANUAL_DISMISS,

                   NULL, NULL, errp);

    if (!s) {

        return;

    }



    s->drv = drv,

    s->opts = QAPI_CLONE(BlockdevCreateOptions, options),



    job_start(&s->common);

}

qapi/block-core.json

+9 −5
Original line number Diff line number Diff line
@@ -4013,14 +4013,18 @@ 
##

# @x-blockdev-create:

#

# Create an image format on a given node.

# TODO Replace with something asynchronous (block job?)

# Starts a job to create an image format on a given node. The job is

# automatically finalized, but a manual job-dismiss is required.

#

# Since: 2.12

# @job-id:          Identifier for the newly created job.

#

# @options:         Options for the image creation.

#

# Since: 3.0

##

{ 'command': 'x-blockdev-create',

  'data': 'BlockdevCreateOptions',

  'boxed': true }

  'data': { 'job-id': 'str',

            'options': 'BlockdevCreateOptions' } }



##

# @blockdev-open-tray:

qapi/job.json

+3 −1
Original line number Diff line number Diff line
@@ -17,10 +17,12 @@ 
#

# @backup: drive backup job type, see "drive-backup"

#

# @create: image creation job type, see "x-blockdev-create" (since 3.0)

#

# Since: 1.7

##

{ 'enum': 'JobType',

  'data': ['commit', 'stream', 'mirror', 'backup'] }

  'data': ['commit', 'stream', 'mirror', 'backup', 'create'] }



##

# @JobStatus:

tests/qemu-iotests/group

+8 −6
Original line number Diff line number Diff line
@@ -204,14 +204,16 @@ 
203 rw auto migration

204 rw auto quick

205 rw auto quick

206 rw auto

207 rw auto

# TODO The following commented out tests need to be reworked to work

# with the x-blockdev-create job

#206 rw auto

#207 rw auto

208 rw auto quick

209 rw auto quick

210 rw auto

211 rw auto quick

212 rw auto quick

213 rw auto quick

#210 rw auto

#211 rw auto quick

#212 rw auto quick

#213 rw auto quick

214 rw auto

215 rw auto quick

216 rw auto quick