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[Qemu-devel] [PULL 16/33] qmp: add internal snapshot support in qmp_tran
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PULL 16/33] qmp: add internal snapshot support in qmp_transaction |
Date: |
Fri, 13 Sep 2013 13:50:46 +0200 |
From: Wenchao Xia <address@hidden>
Unlike savevm, the qmp_transaction interface will not generate
snapshot name automatically, saving trouble to return information
of the new created snapshot.
Although qcow2 support storing multiple snapshots with same name
but different ID, here it will fail when an snapshot with that name
already exist before the operation. Format such as rbd do not support
ID at all, and in most case, it means trouble to user when he faces
multiple snapshots with same name, so ban that case. Request with
empty name will be rejected.
Snapshot ID can't be specified in this interface.
Signed-off-by: Wenchao Xia <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
blockdev.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
qapi-schema.json | 19 ++++++++-
qmp-commands.hx | 34 ++++++++++++----
3 files changed, 160 insertions(+), 9 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 07dac05..0fd30e2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -889,6 +889,117 @@ struct BlkTransactionState {
QSIMPLEQ_ENTRY(BlkTransactionState) entry;
};
+/* internal snapshot private data */
+typedef struct InternalSnapshotState {
+ BlkTransactionState common;
+ BlockDriverState *bs;
+ QEMUSnapshotInfo sn;
+} InternalSnapshotState;
+
+static void internal_snapshot_prepare(BlkTransactionState *common,
+ Error **errp)
+{
+ const char *device;
+ const char *name;
+ BlockDriverState *bs;
+ QEMUSnapshotInfo old_sn, *sn;
+ bool ret;
+ qemu_timeval tv;
+ BlockdevSnapshotInternal *internal;
+ InternalSnapshotState *state;
+ int ret1;
+
+ g_assert(common->action->kind ==
+ TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC);
+ internal = common->action->blockdev_snapshot_internal_sync;
+ state = DO_UPCAST(InternalSnapshotState, common, common);
+
+ /* 1. parse input */
+ device = internal->device;
+ name = internal->name;
+
+ /* 2. check for validation */
+ bs = bdrv_find(device);
+ if (!bs) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+ return;
+ }
+
+ if (!bdrv_is_inserted(bs)) {
+ error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
+ return;
+ }
+
+ if (bdrv_is_read_only(bs)) {
+ error_set(errp, QERR_DEVICE_IS_READ_ONLY, device);
+ return;
+ }
+
+ if (!bdrv_can_snapshot(bs)) {
+ error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+ bs->drv->format_name, device, "internal snapshot");
+ return;
+ }
+
+ if (!strlen(name)) {
+ error_setg(errp, "Name is empty");
+ return;
+ }
+
+ /* check whether a snapshot with name exist */
+ ret = bdrv_snapshot_find_by_id_and_name(bs, NULL, name, &old_sn, errp);
+ if (error_is_set(errp)) {
+ return;
+ } else if (ret) {
+ error_setg(errp,
+ "Snapshot with name '%s' already exists on device '%s'",
+ name, device);
+ return;
+ }
+
+ /* 3. take the snapshot */
+ sn = &state->sn;
+ pstrcpy(sn->name, sizeof(sn->name), name);
+ qemu_gettimeofday(&tv);
+ sn->date_sec = tv.tv_sec;
+ sn->date_nsec = tv.tv_usec * 1000;
+ sn->vm_clock_nsec = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+
+ ret1 = bdrv_snapshot_create(bs, sn);
+ if (ret1 < 0) {
+ error_setg_errno(errp, -ret1,
+ "Failed to create snapshot '%s' on device '%s'",
+ name, device);
+ return;
+ }
+
+ /* 4. succeed, mark a snapshot is created */
+ state->bs = bs;
+}
+
+static void internal_snapshot_abort(BlkTransactionState *common)
+{
+ InternalSnapshotState *state =
+ DO_UPCAST(InternalSnapshotState, common, common);
+ BlockDriverState *bs = state->bs;
+ QEMUSnapshotInfo *sn = &state->sn;
+ Error *local_error = NULL;
+
+ if (!bs) {
+ return;
+ }
+
+ if (bdrv_snapshot_delete(bs, sn->id_str, sn->name, &local_error) < 0) {
+ error_report("Failed to delete snapshot with id '%s' and name '%s' on "
+ "device '%s' in abort: %s",
+ sn->id_str,
+ sn->name,
+ bdrv_get_device_name(bs),
+ error_get_pretty(local_error));
+ error_free(local_error);
+ }
+}
+
/* external snapshot private data */
typedef struct ExternalSnapshotState {
BlkTransactionState common;
@@ -1072,6 +1183,11 @@ static const BdrvActionOps actions[] = {
.prepare = abort_prepare,
.commit = abort_commit,
},
+ [TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC] = {
+ .instance_size = sizeof(InternalSnapshotState),
+ .prepare = internal_snapshot_prepare,
+ .abort = internal_snapshot_abort,
+ },
};
/*
diff --git a/qapi-schema.json b/qapi-schema.json
index 2b2c8bc..77bbbf5 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1686,6 +1686,22 @@
'*mode': 'NewImageMode' } }
##
+# @BlockdevSnapshotInternal
+#
+# @device: the name of the device to generate the snapshot from
+#
+# @name: the name of the internal snapshot to be created
+#
+# Notes: In transaction, if @name is empty, or any snapshot matching @name
+# exists, the operation will fail. Only some image formats support it,
+# for example, qcow2, rbd, and sheepdog.
+#
+# Since: 1.7
+##
+{ 'type': 'BlockdevSnapshotInternal',
+ 'data': { 'device': 'str', 'name': 'str' } }
+
+##
# @DriveBackup
#
# @device: the name of the device which should be copied.
@@ -1747,7 +1763,8 @@
'data': {
'blockdev-snapshot-sync': 'BlockdevSnapshot',
'drive-backup': 'DriveBackup',
- 'abort': 'Abort'
+ 'abort': 'Abort',
+ 'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal'
} }
##
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 008cad9..6670192 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1001,14 +1001,15 @@ SQMP
transaction
-----------
-Atomically operate on one or more block devices. The only supported
-operation for now is snapshotting. If there is any failure performing
-any of the operations, all snapshots for the group are abandoned, and
-the original disks pre-snapshot attempt are used.
+Atomically operate on one or more block devices. The only supported operations
+for now are drive-backup, internal and external snapshotting. A list of
+dictionaries is accepted, that contains the actions to be performed.
+If there is any failure performing any of the operations, all operations
+for the group are abandoned.
-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.
+For external snapshots, the dictionary contains 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
@@ -1017,6 +1018,17 @@ 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.
+On failure, the original disks pre-snapshot attempt will be used.
+
+For internal snapshots, the dictionary contains the device and the snapshot's
+name. If an internal snapshot matching name already exists, the request will
+be rejected. Only some image formats support it, for example, qcow2, rbd,
+and sheepdog.
+
+On failure, qemu will try delete the newly created internal snapshot in the
+transaction. When an I/O error occurs during deletion, the user needs to fix
+it later with qemu-img or other command.
+
Arguments:
actions array:
@@ -1029,6 +1041,9 @@ actions array:
- "format": format of new image (json-string, optional)
- "mode": whether and how QEMU should create the snapshot file
(NewImageMode, optional, default "absolute-paths")
+ When "type" is "blockdev-snapshot-internal-sync":
+ - "device": device name to snapshot (json-string)
+ - "name": name of the new snapshot (json-string)
Example:
@@ -1040,7 +1055,10 @@ Example:
{ 'type': 'blockdev-snapshot-sync', 'data' : { "device": "ide-hd1",
"snapshot-file":
"/some/place/my-image2",
"mode": "existing",
- "format": "qcow2" } } ] } }
+ "format": "qcow2" } },
+ { 'type': 'blockdev-snapshot-internal-sync', 'data' : {
+ "device": "ide-hd2",
+ "name": "snapshot0" } } ] } }
<- { "return": {} }
EQMP
--
1.8.1.4
- [Qemu-devel] [PULL 01/33] qcow2: Pass discard type to qcow2_discard_clusters(), (continued)
- [Qemu-devel] [PULL 01/33] qcow2: Pass discard type to qcow2_discard_clusters(), Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 02/33] qcow2: Discard VM state in active L1 after creating snapshot, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 11/33] qemu-iotests: add infrastructure of fd passing via SCM, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 10/33] qemu-iotests: add unix socket help program, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 09/33] qemu-iotest: qcow2 image option amendment, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 08/33] qcow2: Implement bdrv_amend_options, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 12/33] qemu-iotests: add tests for runtime fd passing via SCM rights, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 13/33] qemu-iotests: New test case in 061, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 15/33] snapshot: distinguish id and name in snapshot delete, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 14/33] snapshot: new function bdrv_snapshot_find_by_id_and_name(), Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 16/33] qmp: add internal snapshot support in qmp_transaction,
Kevin Wolf <=
- [Qemu-devel] [PULL 17/33] qmp: add interface blockdev-snapshot-internal-sync, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 18/33] qmp: add interface blockdev-snapshot-delete-internal-sync, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 19/33] hmp: add interface hmp_snapshot_blkdev_internal, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 20/33] hmp: add interface hmp_snapshot_delete_blkdev_internal, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 21/33] qemu-iotests: add 057 internal snapshot for block device test case, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 22/33] bdrv: Use "Error" for opening images, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 23/33] bdrv: Use "Error" for creating images, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 26/33] qemu-img create: Emit filename on error, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 24/33] block: Error parameter for open functions, Kevin Wolf, 2013/09/13
- [Qemu-devel] [PULL 25/33] block: Error parameter for create functions, Kevin Wolf, 2013/09/13