Re: [Qemu-devel] [PATCH 04/17] blockdev: 'blockdev-add' QMP command

[Fam Zheng]

On Fri, 09/20 13:54, Kevin Wolf wrote:
> For examples see the changes to qmp-commands.hx.
> 
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  blockdev.c       |  57 ++++++++++++
>  qapi-schema.json | 270 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qmp-commands.hx  |  59 ++++++++++++
>  3 files changed, 386 insertions(+)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 977dc94..c4297d8 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -38,6 +38,8 @@
>  #include "qemu/option.h"
>  #include "qemu/config-file.h"
>  #include "qapi/qmp/types.h"
> +#include "qapi-visit.h"
> +#include "qapi/qmp-output-visitor.h"
>  #include "sysemu/sysemu.h"
>  #include "block/block_int.h"
>  #include "qmp-commands.h"
> @@ -2066,6 +2068,61 @@ void qmp_block_job_complete(const char *device, Error 
> **errp)
>      block_job_complete(job, errp);
>  }
>  
> +void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
> +{
> +    QmpOutputVisitor *ov = qmp_output_visitor_new();
> +    QObject *obj;
> +    QDict *qdict;
> +    DriveInfo *dinfo;
> +    Error *local_err = NULL;
> +
> +    /* Require an ID in the top level */
> +    if (!options->has_id) {
> +        error_setg(errp, "Block device needs an ID");
> +        return;
> +    }
> +
> +    /* TODO Sort it out in raw-posix and drive_init: Reject aio=native with
> +     * cache.direct=false instead of silently switching to aio=threads, 
> except
> +     * if called from drive_init.
> +     *
> +     * For now, simply forbidding the combination for all drivers will do. */
> +    if (options->has_aio && options->aio == BLOCKDEV_A_I_O_OPTIONS_NATIVE) {
> +        bool direct = options->cache->has_direct && options->cache->direct;
> +        if (!options->has_cache && !direct) {
> +            error_setg(errp, "aio=native requires cache.direct=true");
> +            goto fail;
> +        }
> +    }
> +
> +    visit_type_BlockdevOptions(qmp_output_get_visitor(ov),
> +                               &options, NULL, &local_err);
> +    if (error_is_set(&local_err)) {
> +        error_propagate(errp, local_err);
> +        goto fail;
> +    }
> +
> +    obj = qmp_output_get_qobject(ov);
> +    qdict = qobject_to_qdict(obj);
> +
> +    qdict_flatten(qdict);
> +
> +    QemuOpts *opts = qemu_opts_from_qdict(&qemu_drive_opts, qdict, 
> &local_err);
> +    if (error_is_set(&local_err)) {
> +        error_propagate(errp, local_err);
> +        goto fail;
> +    } else {
> +        dinfo = blockdev_init(opts, IF_NONE);
> +        if (!dinfo) {
> +            error_setg(errp, "Could not open image");
> +            goto fail;
> +        }
> +    }
> +
> +fail:
> +    qmp_output_visitor_cleanup(ov);
> +}
> +
>  static void do_qmp_query_block_jobs_one(void *opaque, BlockDriverState *bs)
>  {
>      BlockJobInfoList **prev = opaque;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 145eca8..7e8ce60 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3902,3 +3902,273 @@
>  ##
>  { 'command': 'query-rx-filter', 'data': { '*name': 'str' },
>    'returns': ['RxFilterInfo'] }
> +
> +
> +##
> +# @BlockdevDiscardOptions
> +#
> +# Determines how to handle discard requests.
> +#
> +# @ignore:      Ignore the request
> +# @unmap:       Forward as an unmap request
> +#
> +# Since: 1.7
> +##
> +{ 'enum': 'BlockdevDiscardOptions',
> +  'data': [ 'ignore', 'unmap' ] }
> +
> +##
> +# @BlockdevAIOOptions
> +#
> +# Selects the AIO backend to handle I/O requests
> +#
> +# @threads:     Use qemu's thread pool
> +# @native:      Use native AIO backend (only Linux and Windows)
> +#
> +# Since: 1.7
> +##
> +{ 'enum': 'BlockdevAIOOptions',
> +  'data': [ 'threads', 'native' ] }
> +
> +##
> +# @BlockdevCacheOptions
> +#
> +# Includes cache-related options for block devices
> +#
> +# @writeback:   #optional enables writeback mode for any caches (default: 
> true)
> +# @direct:      #optional enables use of O_DIRECT (bypass the host page 
> cache;
> +#               default: false)
> +# @no-flush:    #optional ignore any flush requests for the device (default:
> +#               false)
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevCacheOptions',
> +  'data': { '*writeback': 'bool',
> +            '*direct': 'bool',
> +            '*no-flush': 'bool' } }
> +
> +##
> +# @BlockdevThrottlingOptions
> +#
> +# Includes block device options related to I/O throttling. Leaving an option 
> out
> +# means the same as assigning 0 and applies no throttling.
> +#
> +# @bps-total:   #optional limit total bytes per second
> +# @bps-read:    #optional limit read bytes per second
> +# @bps-write:   #optional limit written bytes per second
> +# @iops-total:  #optional limit total I/O operations per second
> +# @iops-read:   #optional limit read operations per second
> +# @iops-write:  #optional limit write operations per second
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevThrottlingOptions',
> +  'data': { '*bps-total': 'int',
> +            '*bps-read': 'int',
> +            '*bps-write': 'int',
> +            '*iops-total': 'int',
> +            '*iops-read': 'int',
> +            '*iops-write': 'int' } }
> +
> +##
> +# @BlockdevOptionsBase
> +#
> +# Options that are available for all block devices, independent of the block
> +# driver.
> +#
> +# @driver:      block driver name
> +# @id:          #optional id by which the new block device can be referred 
> to.
> +#               This is a required option on the top level of blockdev-add, 
> and
> +#               currently not allowed on any other level.
> +# @discard:     #optional discard-related options (default: ignore)
> +# @cache:       #optional cache-related options
> +# @aio:         #optional AIO backend (default: threads)
> +# @rerror:      #optional how to handle read errors on the device
> +#               (default: report)
> +# @werror:      #optional how to handle write errors on the device
> +#               (default: enospc)
> +# @throttling:  #optional I/O throttling related options
> +# @read-only:   #optional whether the block device should be read-only
> +#               (default: false)
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsBase',
> +  'data': { 'driver': 'str',
> +            '*id': 'str',
> +            '*discard': 'BlockdevDiscardOptions',
> +            '*cache': 'BlockdevCacheOptions',
> +            '*aio':  'BlockdevAIOOptions',
> +            '*rerror': 'BlockdevOnError',
> +            '*werror': 'BlockdevOnError',
> +            '*throttling': 'BlockdevThrottlingOptions',
> +            '*read-only': 'bool' } }
> +
> +##
> +# @BlockdevOptionsFile
> +#
> +# Driver specific block device options for the file backend and similar
> +# protocols.
> +#
> +# @filename:    path to the image file
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsFile',
> +  'data': { 'filename': 'str' } }
> +
> +##
> +# @BlockdevOptionsVVFAT
> +#
> +# Driver specific block device options for the vvfat protocol.
> +#
> +# @dir:         directory to be exported as FAT image
> +# @fat-type:    #optional FAT type: 12, 16 or 32
> +# @floppy:      #optional whether to export a floppy imae (true) or 
> partitioned
> +#               hard disk (false; default)
> +# @rw:          #optional whether to allow write operations (default: false)
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsVVFAT',
> +  'data': { 'dir': 'str', '*fat-type': 'int', '*floppy': 'bool',
> +            '*rw': 'bool' } }
> +
> +##
> +# @BlockdevOptionsGenericFormat
> +#
> +# Driver specific block device options for image format that have no option
> +# besides their data source.
> +#
> +# @file:        reference to or definition of the data source block device
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsGenericFormat',
> +  'data': { 'file': 'BlockdevRef' } }
> +
> +##
> +# @BlockdevOptionsGenericCOWFormat
> +#
> +# Driver specific block device options for image format that have no option
> +# besides their data source and an optional backing file.
> +#
> +# @file:        reference to or definition of the data source block device
> +# @backing:     #optional reference to or definition of the backing file 
> block
> +#               device (if missing, taken from the image file content). It is
> +#               allowed to pass an empty string here in order to disable the
> +#               default backing file.
> +# @copy-on-read: #optional whether to enable copy on read for the device
> +#                (default: false). Copy on read can only be used if the
> +#                image is not read-only.
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsGenericCOWFormat',
> +  'base': 'BlockdevOptionsGenericFormat',
> +  'data': { '*backing': 'BlockdevRef',
> +            '*copy-on-read': 'bool' } }
> +##
> +# @BlockdevOptionsQcow2
> +#
> +# Driver specific block device options for qcow2.
> +#
> +# @file:        reference to or definition of the data source block device
> +#
> +# @backing:     #optional reference to or definition of the backing file 
> block
> +#               device (if missing, taken from the image file content)
> +#
> +# @lazy-refcounts: #optional whether to enable the lazy refcounts feature
> +#                  (default is taken from the image file)
> +#
> +# @pass-discard-request: #optional whether discard requests to the qcow2 
> device
> +#                        should be forwarded to the data source
> +#
> +# @pass-discard-snapshot: #optional whether discard requests for the data 
> source
> +#                         should be issued when a snapshot operation (e.g.
> +#                         deleting a snapshot) frees clusters in the qcow2 
> file
> +#
> +# @pass-discard-other: #optional whether discard requests for the data source
> +#                      should be issued on other occasions where a cluster 
> gets
> +#                      freed
> +#
> +# Since: 1.7
> +##
> +{ 'type': 'BlockdevOptionsQcow2',
> +  'base': 'BlockdevOptionsGenericCOWFormat',
> +  'data': { '*lazy-refcounts': 'bool',
> +            '*pass-discard-request': 'bool',
> +            '*pass-discard-snapshot': 'bool',
> +            '*pass-discard-other': 'bool' } }
> +
> +##
> +# @BlockdevOptions
> +#
> +# Options for creating a block device.
> +#
> +# Since: 1.7
> +##
> +{ 'union': 'BlockdevOptions',
> +  'base': 'BlockdevOptionsBase',
> +  'discriminator': 'driver',
> +  'data': {
> +      'file':       'BlockdevOptionsFile',
> +      'http':       'BlockdevOptionsFile',
> +      'https':      'BlockdevOptionsFile',
> +      'ftp':        'BlockdevOptionsFile',
> +      'ftps':       'BlockdevOptionsFile',
> +      'tftp':       'BlockdevOptionsFile',
> +# TODO gluster: Wait for structured options
> +# TODO iscsi: Wait for structured options
> +# TODO nbd: Should take InetSocketAddress for 'host'?
> +# TODO rbd: Wait for structured options
> +# TODO sheepdog: Wait for structured options
> +# TODO ssh: Should take InetSocketAddress for 'host'?
> +      'vvfat':      'BlockdevOptionsVVFAT',
> +
> +# TODO blkdebug: Wait for structured options
> +# TODO blkverify: Wait for structured options
> +
> +      'bochs':      'BlockdevOptionsGenericFormat',
> +      'cloop':      'BlockdevOptionsGenericFormat',
> +      'cow':        'BlockdevOptionsGenericCOWFormat',
> +      'dmg':        'BlockdevOptionsGenericFormat',
> +      'parallels':  'BlockdevOptionsGenericFormat',
> +      'qcow':       'BlockdevOptionsGenericCOWFormat',
> +      'qcow2':      'BlockdevOptionsQcow2',
> +      'qed':        'BlockdevOptionsGenericCOWFormat',
> +      'raw':        'BlockdevOptionsGenericFormat',
> +      'vdi':        'BlockdevOptionsGenericFormat',
> +      'vhdx':       'BlockdevOptionsGenericFormat',
> +      'vmdk':       'BlockdevOptionsGenericCOWFormat',
> +      'vpc':        'BlockdevOptionsGenericFormat'
> +  } }
> +
> +##
> +# @BlockdevRef
> +#
> +# Reference to a block device.
> +#
> +# @definition:      defines a new block device inline
> +# @reference:       references the ID of an existing block device. An
> +#                   empty string means that no block device should be
> +#                   referenced.
> +#
> +# Since: 1.7
> +##
> +{ 'union': 'BlockdevRef',
> +  'discriminator': {},
> +  'data': { 'definition': 'BlockdevOptions',
> +            'reference': 'str' } }
> +
> +##
> +# @blockdev-add:
> +#
> +# Creates a new block device.
> +#
> +# @options: block device options for the new device
> +#
> +# Since: 1.7
> +##
> +{ 'command': 'blockdev-add', 'data': { 'options': 'BlockdevOptions' } }
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index b17c46e..449ecea 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -3240,3 +3240,62 @@ Example:
>     }
>  
>  EQMP
> +
> +    {
> +        .name       = "blockdev-add",
> +        .args_type  = "options:q",
> +        .mhandler.cmd_new = qmp_marshal_input_blockdev_add,
> +    },
> +
> +SQMP
> +blockdev-add
> +------------
> +
> +Add a block device.
> +
> +Arguments:
> +
> +- "options": block driver options
> +
> +Example (1):
> +
> +-> { "execute": "blockdev-add",
> +    "arguments": { "options" : { "driver": "qcow2",
> +                                 "file": { "driver": "file",
> +                                           "filename": "test.qcow2" } } } }
> +<- { "return": {} }
> +
> +Example (2):
> +
> +-> { "execute": "blockdev-add",
> +     "arguments": {
> +         "options": {
> +           "driver": "qcow2",
> +           "id": "my_disk",
> +           "discard": "unmap",
> +           "throttling": {
> +               "bps-total": 1234567,
> +               "iops-write": 100
> +           },
> +           "cache": {
> +               "direct": true,
> +               "writeback": true
> +           },
> +           "file": {
> +               "driver": "file",
> +               "filename": "/tmp/test.qcow2"
> +           },
> +           "backing": {
> +               "driver": "raw",
> +               "file": {
> +                   "driver": "file",
> +                   "filename": "/dev/fdset/4"
> +               }
> +           }

How will BDS reference be used? Like this?

             "backing": "ide0-hd0",

[As I tested this is not supported with this series, the option "backing" is
not parsed in bdrv_open(). Asking because image fleecing needs this, is it
already in your todo list?]

Thanks,

Fam

> +         }
> +       }
> +     }
> +
> +<- { "return": {} }
> +
> +EQMP
> -- 
> 1.8.1.4
> 
>