A new QMP only command to change the blockdev associated with a block device.
The semantics of change right now are just plain scary. This command introduces
sane semantics. For more details, see the documentation in the schema file.
Signed-off-by: Anthony Liguori <aligu...@us.ibm.com>
---
v1 -> v2
- Rename command to drive-change (Kevin)
---
blockdev.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++---
qapi-schema.json | 30 +++++++++++++++
qmp-commands.hx | 8 ++++
3 files changed, 140 insertions(+), 6 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 07eafce..cd338ed 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -688,12 +688,101 @@ void qmp_block_passwd(const char *device, const char
*password, Error **err)
qmp_set_blockdev_password(device, password, err);
}
+static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
+ int bdrv_flags, BlockDriver *drv,
+ const char *password, Error **errp)
+{
+ if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
+ error_set(errp, QERR_OPEN_FILE_FAILED, filename);
+ return;
+ }
+
+ if (bdrv_key_required(bs)) {
+ if (password) {
+ if (bdrv_set_key(bs, password) < 0) {
+ error_set(errp, QERR_INVALID_PASSWORD);
+ }
+ } else {
+ error_set(errp, QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
+ bdrv_get_encrypted_filename(bs));
+ }
+ } else if (password) {
+ error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
+ }
+}
+
+void qmp_drive_change(const char *device, const char *filename,
+ bool has_format, const char *format,
+ bool has_password, const char *password,
+ Error **errp)
+{
+ BlockDriverState *bs, *bs1;
+ BlockDriver *drv = NULL;
+ int bdrv_flags;
+ Error *err = NULL;
+ bool probed_raw = false;
+
+ bs = bdrv_find(device);
+ if (!bs) {
+ error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+ return;
+ }
+
+ if (has_format) {
+ drv = bdrv_find_whitelisted_format(format);
+ if (!drv) {
+ error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+ return;
+ }
+ }
+
+ bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
+ bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
+
+ if (!has_password) {
+ password = NULL;
+ }
+
+ /* Try to open once with a temporary block device to make sure that
+ * the disk isn't encrypted and we lack a key. This also helps keep
+ * this operation as a transaction. That is, if we fail, we try very
+ * hard to make sure that the state is the same as before the operation
+ * was started.
+ */
+ bs1 = bdrv_new("");
+ qmp_bdrv_open_encrypted(bs1, filename, bdrv_flags, drv, password, &err);
+ if (!has_format && bs1->drv->unsafe_probe) {
+ probed_raw = true;
+ }
+ bdrv_delete(bs1);
+
+ if (err) {
+ error_propagate(errp, err);
+ return;
+ }
+
+ if (probed_raw) {
+ /* We will not auto probe raw files. */
+ error_set(errp, QERR_MISSING_PARAMETER, "format");
+ return;
+ }
+
+ eject_device(bs, 0, &err);
+ if (err) {
+ error_propagate(errp, err);
+ return;
+ }
+
+ qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, password, errp);
+}
+
int do_change_block(Monitor *mon, const char *device,
const char *filename, const char *fmt)
{
BlockDriverState *bs;
BlockDriver *drv = NULL;
int bdrv_flags;
+ Error *err = NULL;
bs = bdrv_find(device);
if (!bs) {
@@ -707,16 +796,23 @@ int do_change_block(Monitor *mon, const char *device,
return -1;
}
}
- if (eject_device(bs, 0, NULL) < 0) {
- return -1;
- }
+
bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
- if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
- qerror_report(QERR_OPEN_FILE_FAILED, filename);
+
+ eject_device(bs, 0, &err);
+ if (err) {
+ qerror_report_err(err);
+ return -1;
+ }
+
+ qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, NULL, &err);
+ if (err) {
+ qerror_report_err(err);
return -1;
}
- return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
+
+ return 0;
}
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
diff --git a/qapi-schema.json b/qapi-schema.json
index 0c6c9b8..cbb5bf1 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -124,3 +124,33 @@
# settings may change after executing this command.
##
{ 'command': 'change-vnc-listen', 'data': {'target': 'str'} }
+
+##
+# @drive-change:
+#
+# This is the preferred interface for changing a block device.
+#
+# @device: The block device name.
+#
+# @filename: The new filename for the block device. This may contain options
+# encoded in a format specified by @format.
+#
+# @format: #optional The format to use open the block device
+#
+# @password: #optional The password to use if the block device is encrypted
+#
+# Returns: Nothing on success.
+# If @device is not a valid block device, DeviceNotFound
+# If @format is not a valid block format, InvalidBlockFormat
+# If @filename is encrypted and @password isn't supplied,
+# DeviceEncrypted. The call should be repeated with @password
+# supplied.
+# If @format is not specified and @filename is a format that cannot
+# be safely probed, MissingParameter.
+# If @filename cannot be opened, OpenFileFailed
+#
+# Since: 1.0
+##
+{ 'command': 'drive-change',
+ 'data': {'device': 'str', 'filename': 'str', '*format': 'str',
+ '*password': 'str'} }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5cab212..623f158 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -121,6 +121,14 @@ EQMP
.mhandler.cmd_new = do_change,
},
+ {
+ .name = "drive-change",
+ .args_type = "device:B,filename:F,format:s?password:s?",
+ .params = "device filename [format] [password]",
+ .help = "change a removable medium, optional format",
+ .mhandler.cmd_new = qmp_marshal_input_drive_change,
+ },
+
SQMP
change
------
--
1.7.4.1
