Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2020-02-06' into staging

}

void qmp_nbd_server_add(const char *device, bool has_name, const char *name,

                        bool has_description, const char *description,

                        bool has_writable, bool writable,

                        bool has_bitmap, const char *bitmap, Error **errp)

{

        return;

    }

    if (has_description && strlen(description) > NBD_MAX_STRING_SIZE) {

        error_setg(errp, "description '%s' too long", description);

        return;

    }

    if (nbd_export_find(name)) {

        error_setg(errp, "NBD server already has export named '%s'", name);

        return;

        writable = false;

    }

    exp = nbd_export_new(bs, 0, len, name, NULL, bitmap, !writable, !writable,

    exp = nbd_export_new(bs, 0, len, name, description, bitmap,

                         !writable, !writable,

                         NULL, false, on_eject_blk, errp);

    if (!exp) {

        goto out;

  Export the disk as read-only.

.. option:: -P, --partition=NUM

  Deprecated: Only expose MBR partition *NUM*.  Understands physical

  partitions 1-4 and logical partition 5. New code should instead use

  :option:`--image-opts` with the raw driver wrapping a subset of the

  original image.

.. option:: -B, --bitmap=NAME

  If *filename* has a qcow2 persistent bitmap *NAME*, expose

    -t -x subset -p 10810 \

    --image-opts driver=raw,offset=1M,size=1M,file.driver=file,file.filename=file.raw

Serve a read-only copy of just the first MBR partition of a guest

image over a Unix socket with as many as 5 simultaneous readers, with

a persistent process forked as a daemon:

Serve a read-only copy of a guest image over a Unix socket with as

many as 5 simultaneous readers, with a persistent process forked as a

daemon:

::

  qemu-nbd --fork --persistent --shared=5 --socket=/path/to/sock \

    --partition=1 --read-only --format=qcow2 file.qcow2

    --read-only --format=qcow2 file.qcow2

Expose the guest-visible contents of a qcow2 file via a block device

/dev/nbd0 (and possibly creating /dev/nbd0p1 and friends for

            continue;

        }

        qmp_nbd_server_add(info->value->device, false, NULL,

        qmp_nbd_server_add(info->value->device, false, NULL, false, NULL,

                           true, writable, false, NULL, &local_err);

        if (local_err != NULL) {

    bool writable = qdict_get_try_bool(qdict, "writable", false);

    Error *local_err = NULL;

    qmp_nbd_server_add(device, !!name, name, true, writable,

    qmp_nbd_server_add(device, !!name, name, false, NULL, true, writable,

                       false, NULL, &local_err);

    hmp_handle_error(mon, local_err);

}

# @name: Export name. If unspecified, the @device parameter is used as the

#        export name. (Since 2.12)

#

# @description: Free-form description of the export, up to 4096 bytes.

#               (Since 5.0)

#

# @writable: Whether clients should be able to write to the device via the

#     NBD connection (default false).

#

# @bitmap: Also export the dirty bitmap reachable from @device, so the

#          NBD client can use NBD_OPT_SET_META_CONTEXT with

#          "qemu:dirty-bitmap:NAME" to inspect the bitmap. (since 4.0)

# Since: 1.3.0

##

{ 'command': 'nbd-server-add',

  'data': {'device': 'str', '*name': 'str', '*writable': 'bool',

           '*bitmap': 'str' } }

  'data': {'device': 'str', '*name': 'str', '*description': 'str',

           '*writable': 'bool', '*bitmap': 'str' } }

##

# @NbdServerRemoveMode:

@section Related binaries

@subsection qemu-nbd --partition (since 4.0.0)

The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})

can only handle MBR partitions, and has never correctly handled

logical partitions beyond partition 5.  If you know the offset and

length of the partition (perhaps by using @code{sfdisk} within the

guest), you can achieve the effect of exporting just that subset of

the disk by use of the @option{--image-opts} option with a raw

blockdev using the @code{offset} and @code{size} parameters layered on

top of any other existing blockdev. For example, if partition 1 is

100MiB long starting at 1MiB, the old command:

@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}

can be rewritten as:

@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}

Alternatively, the @code{nbdkit} project provides a more powerful

partition filter on top of its nbd plugin, which can be used to select

an arbitrary MBR or GPT partition on top of any other full-image NBD

export.  Using this to rewrite the above example results in:

@code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}

@code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}

Note that if you are exposing the export via /dev/nbd0, it is easier

to just export the entire image and then mount only /dev/nbd0p1 than

it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a

subset of the image.

@subsection qemu-img convert -n -o (since 4.2.0)

All options specified in @option{-o} are image creation options, so

The "autoload" parameter has been ignored since 2.12.0. All bitmaps

are automatically loaded from qcow2 images.

@section Related binaries

@subsection qemu-nbd --partition (removed in 5.0.0)

The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})

could only handle MBR partitions, and never correctly handled logical

partitions beyond partition 5.  Exporting a partition can still be

done by utilizing the @option{--image-opts} option with a raw blockdev

using the @code{offset} and @code{size} parameters layered on top of

any other existing blockdev. For example, if partition 1 is 100MiB

long starting at 1MiB, the old command:

@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}

can be rewritten as:

@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2}