Patchwork [2/3] Introduce do_snapshot_blkdev() and monitor command to handle it.

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Submitter Jes Sorensen
Date Dec. 13, 2010, 7:32 a.m.
Message ID <1292225579-27320-3-git-send-email-Jes.Sorensen@redhat.com>
Download mbox | patch
Permalink /patch/75302/
State New
Headers show

Comments

Jes Sorensen - Dec. 13, 2010, 7:32 a.m.
From: Jes Sorensen <Jes.Sorensen@redhat.com>

The monitor command is:
snapshot_blkdev <device> [snapshot-file] [format]

Default format is qcow2. For now snapshots without a snapshot-file, eg
internal snapshots, are not supported.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 blockdev.c      |   61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 blockdev.h      |    1 +
 hmp-commands.hx |   19 +++++++++++++++++
 3 files changed, 81 insertions(+), 0 deletions(-)
Kevin Wolf - Dec. 15, 2010, 4:55 p.m.
Am 13.12.2010 08:32, schrieb Jes.Sorensen@redhat.com:
> From: Jes Sorensen <Jes.Sorensen@redhat.com>
> 
> The monitor command is:
> snapshot_blkdev <device> [snapshot-file] [format]
> 
> Default format is qcow2. For now snapshots without a snapshot-file, eg
> internal snapshots, are not supported.
> 
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  blockdev.c      |   61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  blockdev.h      |    1 +
>  hmp-commands.hx |   19 +++++++++++++++++
>  3 files changed, 81 insertions(+), 0 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index f6ac439..1ea24d7 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -514,6 +514,67 @@ void do_commit(Monitor *mon, const QDict *qdict)
>      }
>  }
>  
> +int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
> +{
> +    const char *device = qdict_get_str(qdict, "device");
> +    const char *filename = qdict_get_try_str(qdict, "snapshot_file");
> +    const char *format = qdict_get_try_str(qdict, "format");
> +    const char format_qcow2[] = "qcow2";
> +    BlockDriverState *bs;
> +    BlockDriver *drv, *proto_drv;
> +    int ret = 0;
> +    int flags;
> +
> +    bs = bdrv_find(device);
> +    if (!bs) {
> +        qerror_report(QERR_DEVICE_NOT_FOUND, device);
> +        ret = -1;
> +        goto out;
> +    }
> +
> +    if (!format) {
> +        format = format_qcow2;
> +    }
> +
> +    drv = bdrv_find_format(format);
> +    if (!drv) {
> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
> +        ret = -1;
> +        goto out;
> +    }
> +
> +    proto_drv = bdrv_find_protocol(filename);
> +    if (!proto_drv) {
> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
> +        ret = -1;
> +        goto out;
> +    }
> +
> +    ret = bdrv_img_create(filename, format, bs->filename,
> +                          bs->drv->format_name, NULL, -1, bs->open_flags);
> +    if (ret) {
> +        goto out;
> +    }
> +
> +    qemu_aio_flush();
> +    bdrv_flush(bs);
> +
> +    flags = bs->open_flags;
> +    bdrv_close(bs);
> +    ret = bdrv_open(bs, filename, flags, drv);
> +    /*
> +     * If reopening the image file we just created fails, we really
> +     * are in trouble :(
> +     */
> +    assert(ret == 0);
> +out:
> +    if (ret) {
> +        ret = 1;

I seem to remember that errors are always -1 for monitor commands.

Kevin
Jes Sorensen - Dec. 15, 2010, 4:57 p.m.
On 12/15/10 17:55, Kevin Wolf wrote:
>> +int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
>> +{
>> +    const char *device = qdict_get_str(qdict, "device");
>> +    const char *filename = qdict_get_try_str(qdict, "snapshot_file");
>> +    const char *format = qdict_get_try_str(qdict, "format");
>> +    const char format_qcow2[] = "qcow2";
>> +    BlockDriverState *bs;
>> +    BlockDriver *drv, *proto_drv;
>> +    int ret = 0;
>> +    int flags;
>> +
>> +    bs = bdrv_find(device);
>> +    if (!bs) {
>> +        qerror_report(QERR_DEVICE_NOT_FOUND, device);
>> +        ret = -1;
>> +        goto out;
>> +    }
>> +
>> +    if (!format) {
>> +        format = format_qcow2;
>> +    }
>> +
>> +    drv = bdrv_find_format(format);
>> +    if (!drv) {
>> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
>> +        ret = -1;
>> +        goto out;
>> +    }
>> +
>> +    proto_drv = bdrv_find_protocol(filename);
>> +    if (!proto_drv) {
>> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
>> +        ret = -1;
>> +        goto out;
>> +    }
>> +
>> +    ret = bdrv_img_create(filename, format, bs->filename,
>> +                          bs->drv->format_name, NULL, -1, bs->open_flags);
>> +    if (ret) {
>> +        goto out;
>> +    }
>> +
>> +    qemu_aio_flush();
>> +    bdrv_flush(bs);
>> +
>> +    flags = bs->open_flags;
>> +    bdrv_close(bs);
>> +    ret = bdrv_open(bs, filename, flags, drv);
>> +    /*
>> +     * If reopening the image file we just created fails, we really
>> +     * are in trouble :(
>> +     */
>> +    assert(ret == 0);
>> +out:
>> +    if (ret) {
>> +        ret = 1;
> 
> I seem to remember that errors are always -1 for monitor commands.

I mapped it after something else, but admitted I cannot remember where -
can someone clarify?

Cheers,
Jes
Luiz Capitulino - Dec. 15, 2010, 5:26 p.m.
On Wed, 15 Dec 2010 17:57:25 +0100
Jes Sorensen <Jes.Sorensen@redhat.com> wrote:

> On 12/15/10 17:55, Kevin Wolf wrote:
> >> +int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
> >> +{
> >> +    const char *device = qdict_get_str(qdict, "device");
> >> +    const char *filename = qdict_get_try_str(qdict, "snapshot_file");
> >> +    const char *format = qdict_get_try_str(qdict, "format");
> >> +    const char format_qcow2[] = "qcow2";
> >> +    BlockDriverState *bs;
> >> +    BlockDriver *drv, *proto_drv;
> >> +    int ret = 0;
> >> +    int flags;
> >> +
> >> +    bs = bdrv_find(device);
> >> +    if (!bs) {
> >> +        qerror_report(QERR_DEVICE_NOT_FOUND, device);
> >> +        ret = -1;
> >> +        goto out;
> >> +    }
> >> +
> >> +    if (!format) {
> >> +        format = format_qcow2;
> >> +    }
> >> +
> >> +    drv = bdrv_find_format(format);
> >> +    if (!drv) {
> >> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
> >> +        ret = -1;
> >> +        goto out;
> >> +    }
> >> +
> >> +    proto_drv = bdrv_find_protocol(filename);
> >> +    if (!proto_drv) {
> >> +        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
> >> +        ret = -1;
> >> +        goto out;
> >> +    }
> >> +
> >> +    ret = bdrv_img_create(filename, format, bs->filename,
> >> +                          bs->drv->format_name, NULL, -1, bs->open_flags);
> >> +    if (ret) {
> >> +        goto out;
> >> +    }
> >> +
> >> +    qemu_aio_flush();
> >> +    bdrv_flush(bs);
> >> +
> >> +    flags = bs->open_flags;
> >> +    bdrv_close(bs);
> >> +    ret = bdrv_open(bs, filename, flags, drv);
> >> +    /*
> >> +     * If reopening the image file we just created fails, we really
> >> +     * are in trouble :(
> >> +     */
> >> +    assert(ret == 0);
> >> +out:
> >> +    if (ret) {
> >> +        ret = 1;
> > 
> > I seem to remember that errors are always -1 for monitor commands.
> 
> I mapped it after something else, but admitted I cannot remember where -
> can someone clarify?

-1

> 
> Cheers,
> Jes
>

Patch

diff --git a/blockdev.c b/blockdev.c
index f6ac439..1ea24d7 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -514,6 +514,67 @@  void do_commit(Monitor *mon, const QDict *qdict)
     }
 }
 
+int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+    const char *device = qdict_get_str(qdict, "device");
+    const char *filename = qdict_get_try_str(qdict, "snapshot_file");
+    const char *format = qdict_get_try_str(qdict, "format");
+    const char format_qcow2[] = "qcow2";
+    BlockDriverState *bs;
+    BlockDriver *drv, *proto_drv;
+    int ret = 0;
+    int flags;
+
+    bs = bdrv_find(device);
+    if (!bs) {
+        qerror_report(QERR_DEVICE_NOT_FOUND, device);
+        ret = -1;
+        goto out;
+    }
+
+    if (!format) {
+        format = format_qcow2;
+    }
+
+    drv = bdrv_find_format(format);
+    if (!drv) {
+        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
+        ret = -1;
+        goto out;
+    }
+
+    proto_drv = bdrv_find_protocol(filename);
+    if (!proto_drv) {
+        qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
+        ret = -1;
+        goto out;
+    }
+
+    ret = bdrv_img_create(filename, format, bs->filename,
+                          bs->drv->format_name, NULL, -1, bs->open_flags);
+    if (ret) {
+        goto out;
+    }
+
+    qemu_aio_flush();
+    bdrv_flush(bs);
+
+    flags = bs->open_flags;
+    bdrv_close(bs);
+    ret = bdrv_open(bs, filename, flags, drv);
+    /*
+     * If reopening the image file we just created fails, we really
+     * are in trouble :(
+     */
+    assert(ret == 0);
+out:
+    if (ret) {
+        ret = 1;
+    }
+
+    return ret;
+}
+
 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 {
     if (!force) {
diff --git a/blockdev.h b/blockdev.h
index 4cb8ca9..4536b5c 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -52,5 +52,6 @@  int do_block_set_passwd(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_change_block(Monitor *mon, const char *device,
                     const char *filename, const char *fmt);
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
+int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data);
 
 #endif
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 23024ba..97e744e 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -801,6 +801,25 @@  STEXI
 Set maximum tolerated downtime (in seconds) for migration.
 ETEXI
 
+    {
+        .name       = "snapshot_blkdev",
+        .args_type  = "device:s,snapshot_file:s?,format:s?",
+        .params     = "device [snapshot-file] [format]",
+        .help       = "initiates a live snapshot\n\t\t\t"
+                      "of device. If a snapshot file is specified, the\n\t\t\t"
+                      "snapshot file will become the new root image. If\n\t\t\t"
+                      "format is specified, the snapshot file will be\n\t\t\t"
+                      "created in that format. Otherwise the snapshot\n\t\t\t"
+                      "will be internal! (currently unsupported)",
+        .mhandler.cmd_new = do_snapshot_blkdev,
+    },
+
+STEXI
+@item snapshot_blkdev
+@findex snapshot_blkdev
+Snapshot device, using snapshot file as target if provided
+ETEXI
+
 #if defined(TARGET_I386)
     {
         .name       = "drive_add",