[Qemu-devel] [PATCH] hmp: Add nbd_server_remove to mirror QMP command

[Qemu-devel] [PATCH] hmp: Add nbd_server_remove to mirror QMP command

[Eric Blake]

Since everything else about the nbd-server-* QMP commands is
accessible from HMP, we might as well make removing an export
available as well.  For now, I went with a bool flag rather
than a mode string for choosing between safe (default) and
hard modes.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

Based-on: <20180119135719.24745-1-vsementsov@virtuozzo.com>
([PATCH v3 0/5] nbd export qmp interface)

 hmp.h           |  1 +
 hmp.c           | 14 +++++++++++---
 hmp-commands.hx | 17 +++++++++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/hmp.h b/hmp.h
index a6f56b1f29e..536cb91caa4 100644
--- a/hmp.h
+++ b/hmp.h
@@ -101,6 +101,7 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict);
 void hmp_screendump(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
+void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
 void hmp_chardev_add(Monitor *mon, const QDict *qdict);
 void hmp_chardev_change(Monitor *mon, const QDict *qdict);
diff --git a/hmp.c b/hmp.c
index 7a64dd59c5c..b3de32d219b 100644
--- a/hmp.c
+++ b/hmp.c
@@ -2226,10 +2226,18 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
     Error *local_err = NULL;

     qmp_nbd_server_add(device, !!name, name, true, writable, &local_err);
+    hmp_handle_error(mon, &local_err);
+}

-    if (local_err != NULL) {
-        hmp_handle_error(mon, &local_err);
-    }
+void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict)
+{
+    const char *name = qdict_get_str(qdict, "name");
+    bool force = qdict_get_try_bool(qdict, "force", false);
+    Error *err = NULL;
+
+    /* Rely on NBD_SERVER_REMOVE_MODE_SAFE being the default */
+    qmp_nbd_server_remove(name, force, NBD_SERVER_REMOVE_MODE_HARD, &err);
+    hmp_handle_error(mon, &err);
 }

 void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index b8b6fb91848..8a59338bc20 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1565,6 +1565,23 @@ Export a block device through QEMU's NBD server, which must be started
 beforehand with @command{nbd_server_start}.  The @option{-w} option makes the
 exported device writable too.  The export name is controlled by @var{name},
 defaulting to @var{device}.
+ETEXI
+
+    {
+        .name       = "nbd_server_remove",
+        .args_type  = "force:-f,name:s",
+        .params     = "nbd_server_remove [-f] name",
+        .help       = "remove an export previously exposed via NBD",
+        .cmd        = hmp_nbd_server_remove,
+    },
+STEXI
+@item nbd_server_remove [-f] @var{name}
+@findex nbd_server_remove
+Stop exporting a block device through QEMU's NBD server, which was
+previously started with @command{nbd_server_add}.  The @option{-f}
+option forces the server to drop the export immediately even if
+clients are connected; otherwise the command fails unless there are no
+clients.
 ETEXI

     {
-- 
2.14.3

Re: [Qemu-devel] [PATCH] hmp: Add nbd_server_remove to mirror QMP command

[Eric Blake]

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On 01/25/2018 08:45 AM, Eric Blake wrote:
> Since everything else about the nbd-server-* QMP commands is
> accessible from HMP, we might as well make removing an export
> available as well.  For now, I went with a bool flag rather
> than a mode string for choosing between safe (default) and
> hard modes.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
> 
> Based-on: <20180119135719.24745-1-vsementsov@virtuozzo.com>
> ([PATCH v3 0/5] nbd export qmp interface)

Since that series is on my NBD queue, I'm happy to take this one through
the NBD queue as well rather than the HMP queue.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PATCH] hmp: Add nbd_server_remove to mirror QMP command

[Dr. David Alan Gilbert]

* Eric Blake (eblake@redhat.com) wrote:
> Since everything else about the nbd-server-* QMP commands is
> accessible from HMP, we might as well make removing an export
> available as well.  For now, I went with a bool flag rather
> than a mode string for choosing between safe (default) and
> hard modes.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>

For the HMP side of things:
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

and yes, if you've already got the rest of it on your NBD queue
just add this one into your queue.

Dave
> ---
> 
> Based-on: <20180119135719.24745-1-vsementsov@virtuozzo.com>
> ([PATCH v3 0/5] nbd export qmp interface)
> 
>  hmp.h           |  1 +
>  hmp.c           | 14 +++++++++++---
>  hmp-commands.hx | 17 +++++++++++++++++
>  3 files changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/hmp.h b/hmp.h
> index a6f56b1f29e..536cb91caa4 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -101,6 +101,7 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict);
>  void hmp_screendump(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
> +void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
>  void hmp_chardev_add(Monitor *mon, const QDict *qdict);
>  void hmp_chardev_change(Monitor *mon, const QDict *qdict);
> diff --git a/hmp.c b/hmp.c
> index 7a64dd59c5c..b3de32d219b 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -2226,10 +2226,18 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
>      Error *local_err = NULL;
> 
>      qmp_nbd_server_add(device, !!name, name, true, writable, &local_err);
> +    hmp_handle_error(mon, &local_err);
> +}
> 
> -    if (local_err != NULL) {
> -        hmp_handle_error(mon, &local_err);
> -    }
> +void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict)
> +{
> +    const char *name = qdict_get_str(qdict, "name");
> +    bool force = qdict_get_try_bool(qdict, "force", false);
> +    Error *err = NULL;
> +
> +    /* Rely on NBD_SERVER_REMOVE_MODE_SAFE being the default */
> +    qmp_nbd_server_remove(name, force, NBD_SERVER_REMOVE_MODE_HARD, &err);
> +    hmp_handle_error(mon, &err);
>  }
> 
>  void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index b8b6fb91848..8a59338bc20 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1565,6 +1565,23 @@ Export a block device through QEMU's NBD server, which must be started
>  beforehand with @command{nbd_server_start}.  The @option{-w} option makes the
>  exported device writable too.  The export name is controlled by @var{name},
>  defaulting to @var{device}.
> +ETEXI
> +
> +    {
> +        .name       = "nbd_server_remove",
> +        .args_type  = "force:-f,name:s",
> +        .params     = "nbd_server_remove [-f] name",
> +        .help       = "remove an export previously exposed via NBD",
> +        .cmd        = hmp_nbd_server_remove,
> +    },
> +STEXI
> +@item nbd_server_remove [-f] @var{name}
> +@findex nbd_server_remove
> +Stop exporting a block device through QEMU's NBD server, which was
> +previously started with @command{nbd_server_add}.  The @option{-f}
> +option forces the server to drop the export immediately even if
> +clients are connected; otherwise the command fails unless there are no
> +clients.
>  ETEXI
> 
>      {
> -- 
> 2.14.3
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] [Qemu-block] [PATCH] hmp: Add nbd_server_remove to mirror QMP command

[Kevin Wolf]

Am 25.01.2018 um 15:45 hat Eric Blake geschrieben:
> Since everything else about the nbd-server-* QMP commands is
> accessible from HMP, we might as well make removing an export
> available as well.  For now, I went with a bool flag rather
> than a mode string for choosing between safe (default) and
> hard modes.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
> 
> Based-on: <20180119135719.24745-1-vsementsov@virtuozzo.com>
> ([PATCH v3 0/5] nbd export qmp interface)
> 
>  hmp.h           |  1 +
>  hmp.c           | 14 +++++++++++---
>  hmp-commands.hx | 17 +++++++++++++++++
>  3 files changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/hmp.h b/hmp.h
> index a6f56b1f29e..536cb91caa4 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -101,6 +101,7 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict);
>  void hmp_screendump(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
> +void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict);
>  void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
>  void hmp_chardev_add(Monitor *mon, const QDict *qdict);
>  void hmp_chardev_change(Monitor *mon, const QDict *qdict);
> diff --git a/hmp.c b/hmp.c
> index 7a64dd59c5c..b3de32d219b 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -2226,10 +2226,18 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
>      Error *local_err = NULL;
> 
>      qmp_nbd_server_add(device, !!name, name, true, writable, &local_err);
> +    hmp_handle_error(mon, &local_err);
> +}
> 
> -    if (local_err != NULL) {
> -        hmp_handle_error(mon, &local_err);
> -    }
> +void hmp_nbd_server_remove(Monitor *mon, const QDict *qdict)
> +{
> +    const char *name = qdict_get_str(qdict, "name");
> +    bool force = qdict_get_try_bool(qdict, "force", false);
> +    Error *err = NULL;
> +
> +    /* Rely on NBD_SERVER_REMOVE_MODE_SAFE being the default */
> +    qmp_nbd_server_remove(name, force, NBD_SERVER_REMOVE_MODE_HARD, &err);

Usually we pass has_* = true and don't rely on defaults which may change
in the long run. Might also make the code a bit easier to understand, as
the existence of your comment shows.

> +    hmp_handle_error(mon, &err);
>  }

Either way:

Reviewed-by: Kevin Wolf <kwolf@redhat.com>