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Re: [PATCH v2 for 7.1 1/1] block: add 'force' parameter to 'blockdev-cha
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From: |
Dr. David Alan Gilbert |
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Subject: |
Re: [PATCH v2 for 7.1 1/1] block: add 'force' parameter to 'blockdev-change-medium' command |
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Date: |
Tue, 12 Apr 2022 11:42:43 +0100 |
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User-agent: |
Mutt/2.2.1 (2022-02-19) |
* Denis V. Lunev (den@openvz.org) wrote:
> 'blockdev-change-medium' is a convinient wrapper for the following
> sequence of commands:
> * blockdev-open-tray
> * blockdev-remove-medium
> * blockdev-insert-medium
> * blockdev-close-tray
> and should be used f.e. to change ISO image inside the CD-ROM tray.
> Though the guest could lock the tray and some linux guests like
> CentOS 8.5 actually does that. In this case the execution if this
> command results in the error like the following:
> Device 'scsi0-0-1-0' is locked and force was not specified,
> wait for tray to open and try again.
>
> This situation is could be resolved 'blockdev-open-tray' by passing
> flag 'force' inside. Thus is seems reasonable to add the same
> capability for 'blockdev-change-medium' too.
For HMP:
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(Although I'd be pretty careful with this; a guest OS might feel like
it could ignore anything else that was going on and keep it's data
cached if it had it's drive locked).
Dave
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Hanna Reitz <hreitz@redhat.com>
> CC: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> CC: Eric Blake <eblake@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
> ---
> block/qapi-sysemu.c | 3 ++-
> hmp-commands.hx | 11 +++++++----
> monitor/hmp-cmds.c | 4 +++-
> qapi/block.json | 6 ++++++
> ui/cocoa.m | 1 +
> 5 files changed, 19 insertions(+), 6 deletions(-)
>
> Changes from v1:
> - added kludge to Objective C code
> - simplified a bit call of do_open_tray() (thanks, Vova!)
> - added record to hmp-command.hx
>
> diff --git a/block/qapi-sysemu.c b/block/qapi-sysemu.c
> index 8498402ad4..680c7ee342 100644
> --- a/block/qapi-sysemu.c
> +++ b/block/qapi-sysemu.c
> @@ -318,6 +318,7 @@ void qmp_blockdev_change_medium(bool has_device, const
> char *device,
> bool has_id, const char *id,
> const char *filename,
> bool has_format, const char *format,
> + bool has_force, bool force,
> bool has_read_only,
> BlockdevChangeReadOnlyMode read_only,
> Error **errp)
> @@ -380,7 +381,7 @@ void qmp_blockdev_change_medium(bool has_device, const
> char *device,
>
> rc = do_open_tray(has_device ? device : NULL,
> has_id ? id : NULL,
> - false, &err);
> + force, &err);
> if (rc && rc != -ENOSYS) {
> error_propagate(errp, err);
> goto fail;
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 8476277aa9..6ec593ea08 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -202,9 +202,9 @@ ERST
>
> {
> .name = "change",
> - .args_type = "device:B,target:F,arg:s?,read-only-mode:s?",
> - .params = "device filename [format [read-only-mode]]",
> - .help = "change a removable medium, optional format",
> + .args_type = "device:B,force:-f,target:F,arg:s?,read-only-mode:s?",
> + .params = "device [-f] filename [format [read-only-mode]]",
> + .help = "change a removable medium, optional format, use -f to
> force the operation",
> .cmd = hmp_change,
> },
>
> @@ -212,11 +212,14 @@ SRST
> ``change`` *device* *setting*
> Change the configuration of a device.
>
> - ``change`` *diskdevice* *filename* [*format* [*read-only-mode*]]
> + ``change`` *diskdevice* [-f] *filename* [*format* [*read-only-mode*]]
> Change the medium for a removable disk device to point to *filename*.
> eg::
>
> (qemu) change ide1-cd0 /path/to/some.iso
>
> + ``-f``
> + forces the operation even if the guest has locked the tray.
> +
> *format* is optional.
>
> *read-only-mode* may be used to change the read-only status of the
> device.
> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index 634968498b..d8b98bed6c 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -1472,6 +1472,7 @@ void hmp_change(Monitor *mon, const QDict *qdict)
> const char *target = qdict_get_str(qdict, "target");
> const char *arg = qdict_get_try_str(qdict, "arg");
> const char *read_only = qdict_get_try_str(qdict, "read-only-mode");
> + bool force = qdict_get_try_bool(qdict, "force", false);
> BlockdevChangeReadOnlyMode read_only_mode = 0;
> Error *err = NULL;
>
> @@ -1508,7 +1509,8 @@ void hmp_change(Monitor *mon, const QDict *qdict)
> }
>
> qmp_blockdev_change_medium(true, device, false, NULL, target,
> - !!arg, arg, !!read_only, read_only_mode,
> + !!arg, arg, true, force,
> + !!read_only, read_only_mode,
> &err);
> }
>
> diff --git a/qapi/block.json b/qapi/block.json
> index 82fcf2c914..3f100d4887 100644
> --- a/qapi/block.json
> +++ b/qapi/block.json
> @@ -326,6 +326,11 @@
> # @read-only-mode: change the read-only mode of the device; defaults
> # to 'retain'
> #
> +# @force: if false (the default), an eject request through blockdev-open-tray
> +# will be sent to the guest if it has locked the tray (and the tray
> +# will not be opened immediately); if true, the tray will be opened
> +# regardless of whether it is locked. (since 7.1)
> +#
> # Features:
> # @deprecated: Member @device is deprecated. Use @id instead.
> #
> @@ -367,6 +372,7 @@
> '*id': 'str',
> 'filename': 'str',
> '*format': 'str',
> + '*force': 'bool',
> '*read-only-mode': 'BlockdevChangeReadOnlyMode' } }
>
>
> diff --git a/ui/cocoa.m b/ui/cocoa.m
> index c4e5468f9e..a931174397 100644
> --- a/ui/cocoa.m
> +++ b/ui/cocoa.m
> @@ -1529,6 +1529,7 @@ - (void)changeDeviceMedia:(id)sender
> false, NULL,
> [file cStringUsingEncoding:
> NSASCIIStringEncoding],
> + true, false,
> true, "raw",
> false, 0,
> &err);
> --
> 2.32.0
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK