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[Qemu-devel] [PATCH 12/20] add mode field to blockdev-snapshot-sync tran
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 12/20] add mode field to blockdev-snapshot-sync transaction item |
Date: |
Mon, 12 Mar 2012 16:19:43 +0100 |
From: Paolo Bonzini <address@hidden>
The mode field lets a management application create the snapshot
destination outside QEMU.
Right now, the only modes are "existing" and "absolute-paths". Mirroring
introduces "no-backing-file". In the future "relative-paths" could be
implemented too.
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
blockdev.c | 25 ++++++++++++++++---------
qapi-schema.json | 19 ++++++++++++++++++-
qmp-commands.hx | 10 ++++++++++
3 files changed, 44 insertions(+), 10 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 88730c1..0a6edc3 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -748,9 +748,10 @@ void qmp_transaction(BlockdevActionList *dev_list, Error
**errp)
BlockDriver *proto_drv;
BlockDriver *drv;
int flags;
+ enum NewImageMode mode;
+ const char *new_image_file;
const char *device;
const char *format = "qcow2";
- const char *new_image_file = NULL;
dev_info = dev_entry->value;
dev_entry = dev_entry->next;
@@ -761,10 +762,14 @@ void qmp_transaction(BlockdevActionList *dev_list, Error
**errp)
switch (dev_info->kind) {
case BLOCKDEV_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC:
device = dev_info->blockdev_snapshot_sync->device;
+ if (!dev_info->blockdev_snapshot_sync->has_mode) {
+ dev_info->blockdev_snapshot_sync->mode =
NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+ }
+ new_image_file = dev_info->blockdev_snapshot_sync->snapshot_file;
if (dev_info->blockdev_snapshot_sync->has_format) {
format = dev_info->blockdev_snapshot_sync->format;
}
- new_image_file = dev_info->blockdev_snapshot_sync->snapshot_file;
+ mode = dev_info->blockdev_snapshot_sync->mode;
break;
default:
abort();
@@ -805,13 +810,15 @@ void qmp_transaction(BlockdevActionList *dev_list, Error
**errp)
}
/* create new image w/backing file */
- ret = bdrv_img_create(new_image_file, format,
- states->old_bs->filename,
- states->old_bs->drv->format_name,
- NULL, -1, flags);
- if (ret) {
- error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
- goto delete_and_fail;
+ if (mode != NEW_IMAGE_MODE_EXISTING) {
+ ret = bdrv_img_create(new_image_file, format,
+ states->old_bs->filename,
+ states->old_bs->drv->format_name,
+ NULL, -1, flags);
+ if (ret) {
+ error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
+ goto delete_and_fail;
+ }
}
/* We will manually add the backing_hd field to the bs later */
diff --git a/qapi-schema.json b/qapi-schema.json
index 85de38e..0882f43 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1118,6 +1118,22 @@
{ 'command': 'block_resize', 'data': { 'device': 'str', 'size': 'int' }}
##
+# @NewImageMode
+#
+# An enumeration that tells QEMU how to set the backing file path in
+# a new image file.
+#
+# @existing: QEMU should look for an existing image file.
+#
+# @absolute-paths: QEMU should create a new image with absolute paths
+# for the backing file.
+#
+# Since: 1.1
+##
+{ 'enum': 'NewImageMode'
+ 'data': [ 'existing', 'absolute-paths' ] }
+
+##
# @BlockdevSnapshot
#
# @device: the name of the device to generate the snapshot from.
@@ -1127,7 +1143,8 @@
# @format: #optional the format of the snapshot image, default is 'qcow2'.
##
{ 'type': 'BlockdevSnapshot',
- 'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str' } }
+ 'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str',
+ '*mode': 'NewImageMode' } }
##
# @BlockdevAction
diff --git a/qmp-commands.hx b/qmp-commands.hx
index fb4f1df..7c03b62 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -705,6 +705,13 @@ A list of dictionaries is accepted, that contains the
actions to be performed.
For snapshots this is the device, the file to use for the new snapshot,
and the format. The default format, if not specified, is qcow2.
+Each new snapshot defaults to being created by QEMU (wiping any
+contents if the file already exists), but it is also possible to reuse
+an externally-created file. In the latter case, you should ensure that
+the new image file has the same contents as the current one; QEMU cannot
+perform any meaningful check. Typically this is achieved by using the
+current image file as the backing file for the new image.
+
Arguments:
actions array:
@@ -715,6 +722,8 @@ actions array:
- "device": device name to snapshot (json-string)
- "snapshot-file": name of new image file (json-string)
- "format": format of new image (json-string, optional)
+ - "mode": whether and how QEMU should create the snapshot file
+ (NewImageMode, optional, default "absolute-paths")
Example:
@@ -725,6 +734,7 @@ Example:
"format": "qcow2" } },
{ 'type': 'blockdev-snapshot-sync', 'data' : { "device": "ide-hd1",
"snapshot-file":
"/some/place/my-image2",
+ "mode": "existing",
"format": "qcow2" } } ] } }
<- { "return": {} }
--
1.7.6.5
- [Qemu-devel] [PATCH 16/20] qcow2: Reduce number of I/O requests, (continued)
- [Qemu-devel] [PATCH 16/20] qcow2: Reduce number of I/O requests, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 03/20] qcow2: Add some tracing, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 17/20] coroutine: adding sigaltstack method (.c source), Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 18/20] coroutine: adding configure choose mechanism for coroutine backend, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 10/20] qapi: complete implementation of unions, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 04/20] block: handle -EBUSY in bdrv_commit_all(), Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 20/20] test-coroutine: add performance test for nesting, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 07/20] make check: Add qemu-iotests subset, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 14/20] qcow2: Factor out count_cow_clusters, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 09/20] use QSIMPLEQ_FOREACH_SAFE when freeing list elements, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 12/20] add mode field to blockdev-snapshot-sync transaction item,
Kevin Wolf <=
- [Qemu-devel] [PATCH 19/20] coroutine: adding configure option for sigaltstack coroutine backend, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 13/20] qmp: convert blockdev-snapshot-sync to a wrapper around transactions, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 11/20] rename blockdev-group-snapshot-sync, Kevin Wolf, 2012/03/12
- [Qemu-devel] [PATCH 15/20] qcow2: Add qcow2_alloc_clusters_at(), Kevin Wolf, 2012/03/12
- Re: [Qemu-devel] [PULL 00/20] Block patches, Anthony Liguori, 2012/03/12