Patchwork [v3,5/6] QAPI: add command for live block commit, 'block-commit'

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Submitter Jeff Cody
Date Sept. 27, 2012, 5:29 p.m.
Message ID <327f7d715621f55ee9d1dfd0a3eba6138ffe9345.1348760202.git.jcody@redhat.com>
Download mbox | patch
Permalink /patch/187424/
State New
Headers show

Comments

Jeff Cody - Sept. 27, 2012, 5:29 p.m.
The command for live block commit is added, which has the following
arguments:

device: the block device to perform the commit on (mandatory)
base:   the base image to commit into; optional (if not specified,
        it is the underlying original image)
top:    the top image of the commit - all data from inside top down
        to base will be committed into base (mandatory for now; see
        note, below)

speed:  maximum speed, in bytes/sec

Note: Eventually this command will support merging down the active layer,
      but that code is not yet complete.  If the active layer is passed
      in as top, then an error will be returned.  Once merging down the
      active layer is supported, the 'top' argument may become optional,
      and default to the active layer.

The is done as a block job, so upon completion a BLOCK_JOB_COMPLETED will
be emitted.

Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 QMP/qmp-events.txt |  6 ++++--
 blockdev.c         | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi-schema.json   | 34 ++++++++++++++++++++++++++++++++
 qmp-commands.hx    |  6 ++++++
 4 files changed, 102 insertions(+), 2 deletions(-)
Eric Blake - Sept. 27, 2012, 5:57 p.m.
On 09/27/2012 11:29 AM, Jeff Cody wrote:
> The command for live block commit is added, which has the following
> arguments:
> 
> device: the block device to perform the commit on (mandatory)
> base:   the base image to commit into; optional (if not specified,
>         it is the underlying original image)
> top:    the top image of the commit - all data from inside top down
>         to base will be committed into base (mandatory for now; see
>         note, below)
> 

> +++ b/qmp-commands.hx
> @@ -792,6 +792,12 @@ EQMP
>      },
>  
>      {
> +        .name       = "block-commit",
> +        .args_type  = "device:B,base:s?,top:s?,speed:o?",

s/top:s?/top:s/ now that top is mandatory.
Jeff Cody - Sept. 27, 2012, 6:01 p.m.
On 09/27/2012 01:57 PM, Eric Blake wrote:
> On 09/27/2012 11:29 AM, Jeff Cody wrote:
>> The command for live block commit is added, which has the following
>> arguments:
>>
>> device: the block device to perform the commit on (mandatory)
>> base:   the base image to commit into; optional (if not specified,
>>         it is the underlying original image)
>> top:    the top image of the commit - all data from inside top down
>>         to base will be committed into base (mandatory for now; see
>>         note, below)
>>
> 
>> +++ b/qmp-commands.hx
>> @@ -792,6 +792,12 @@ EQMP
>>      },
>>  
>>      {
>> +        .name       = "block-commit",
>> +        .args_type  = "device:B,base:s?,top:s?,speed:o?",
> 
> s/top:s?/top:s/ now that top is mandatory.
> 

Right, forgot the hx file.  Although, QAPI catches it just fine
regardless of the hx file... but I will spin that really quick
(hopefully that is the only change required), unless Kevin wants to do
it when he pulls it into his branch.

Patch

diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index 2878058..4491020 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -50,7 +50,8 @@  Emitted when a block job has been cancelled.
 
 Data:
 
-- "type":     Job type ("stream" for image streaming, json-string)
+- "type":     Job type (json-string; "stream" for image streaming
+                                     "commit" for block commit)
 - "device":   Device name (json-string)
 - "len":      Maximum progress value (json-int)
 - "offset":   Current progress value (json-int)
@@ -73,7 +74,8 @@  Emitted when a block job has completed.
 
 Data:
 
-- "type":     Job type ("stream" for image streaming, json-string)
+- "type":     Job type (json-string; "stream" for image streaming
+                                     "commit" for block commit)
 - "device":   Device name (json-string)
 - "len":      Maximum progress value (json-int)
 - "offset":   Current progress value (json-int)
diff --git a/blockdev.c b/blockdev.c
index 9caa16f..946e3c2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1124,6 +1124,64 @@  void qmp_block_stream(const char *device, bool has_base,
     trace_qmp_block_stream(bs, bs->job);
 }
 
+void qmp_block_commit(const char *device,
+                      bool has_base, const char *base, const char *top,
+                      bool has_speed, int64_t speed,
+                      Error **errp)
+{
+    BlockDriverState *bs;
+    BlockDriverState *base_bs, *top_bs;
+    Error *local_err = NULL;
+    /* This will be part of the QMP command, if/when the
+     * BlockdevOnError change for blkmirror makes it in
+     */
+    BlockErrorAction on_error = BLOCK_ERR_REPORT;
+
+    /* drain all i/o before commits */
+    bdrv_drain_all();
+
+    bs = bdrv_find(device);
+    if (!bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
+    }
+    if (base && has_base) {
+        base_bs = bdrv_find_backing_image(bs, base);
+    } else {
+        base_bs = bdrv_find_base(bs);
+    }
+
+    if (base_bs == NULL) {
+        error_set(errp, QERR_BASE_NOT_FOUND, base ? base : "NULL");
+        return;
+    }
+
+    /* default top_bs is the active layer */
+    top_bs = bs;
+
+    if (top) {
+        if (strcmp(bs->filename, top) != 0) {
+            top_bs = bdrv_find_backing_image(bs, top);
+        }
+    }
+
+    if (top_bs == NULL) {
+        error_setg(errp, "Top image file %s not found", top ? top : "NULL");
+        return;
+    }
+
+    commit_start(bs, base_bs, top_bs, speed, on_error, block_job_cb, bs,
+                &local_err);
+    if (local_err != NULL) {
+        error_propagate(errp, local_err);
+        return;
+    }
+    /* Grab a reference so hotplug does not delete the BlockDriverState from
+     * underneath us.
+     */
+    drive_get_ref(drive_get_by_blockdev(bs));
+}
+
 static BlockJob *find_block_job(const char *device)
 {
     BlockDriverState *bs;
diff --git a/qapi-schema.json b/qapi-schema.json
index 14e4419..5816545 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1468,6 +1468,40 @@ 
   'returns': 'str' }
 
 ##
+# @block-commit
+#
+# Live commit of data from overlay image nodes into backing nodes - i.e.,
+# writes data between 'top' and 'base' into 'base'.
+#
+# @device:  the name of the device
+#
+# @base:   #optional The file name of the backing image to write data into.
+#                    If not specified, this is the deepest backing image
+#
+# @top:              The file name of the backing image within the image chain,
+#                    which contains the topmost data to be committed down.
+#                    Note, the active layer as 'top' is currently unsupported.
+#
+#                    If top == base, that is an error.
+#
+#
+# @speed:  #optional the maximum speed, in bytes per second
+#
+# Returns: Nothing on success
+#          If commit or stream is already active on this device, DeviceInUse
+#          If @device does not exist, DeviceNotFound
+#          If image commit is not supported by this device, NotSupported
+#          If @base or @top is invalid, a generic error is returned
+#          If @top is the active layer, or omitted, a generic error is returned
+#          If @speed is invalid, InvalidParameter
+#
+# Since: 1.3
+#
+##
+{ 'command': 'block-commit',
+  'data': { 'device': 'str', '*base': 'str', 'top': 'str',
+            '*speed': 'int' } }
+
 # @migrate_cancel
 #
 # Cancel the current executing migration process.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 6e21ddb..e244763 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -792,6 +792,12 @@  EQMP
     },
 
     {
+        .name       = "block-commit",
+        .args_type  = "device:B,base:s?,top:s?,speed:o?",
+        .mhandler.cmd_new = qmp_marshal_input_block_commit,
+    },
+
+    {
         .name       = "block-job-set-speed",
         .args_type  = "device:B,speed:o",
         .mhandler.cmd_new = qmp_marshal_input_block_job_set_speed,