This allows to change (replace) the file on a block device and is useful
to workaround exclusive file access restrictions, e.g. to implement VM
migration with a shared disk stored on some storage with the exclusive
file opening model: a destination VM is started waiting for incomming
migration with a fake image drive, and later, on the last migration
phase, the fake image file is replaced with the real one.
Signed-off-by: Denis Plotnikov <dplotni...@virtuozzo.com>
---
hw/core/qdev-properties-system.c | 89 +++++++++++++++++++++++++++-----
1 file changed, 77 insertions(+), 12 deletions(-)
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index c534590dcd..aaab1370a4 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -79,8 +79,55 @@ static void set_pointer(Object *obj, Visitor *v, Property
*prop,
/* --- drive --- */
-static void do_parse_drive(DeviceState *dev, const char *str, void **ptr,
- const char *propname, bool iothread, Error **errp)
+static void do_parse_drive_realized(DeviceState *dev, const char *str,
+ void **ptr, const char *propname,
+ bool iothread, Error **errp)
+{
+ BlockBackend *blk = *ptr;
+ BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL);
+ int ret;
+ bool blk_created = false;
+
+ if (!bs) {
+ error_setg(errp, "Can't find blockdev '%s'", str);
+ return;
+ }
+
+ if (!blk) {
+ AioContext *ctx = iothread ? bdrv_get_aio_context(bs) :
+ qemu_get_aio_context();
+ blk = blk_new(ctx, BLK_PERM_ALL, BLK_PERM_ALL);
+ blk_created = true;
+ } else {
+ if (blk_bs(blk)) {
+ blk_remove_bs(blk);
+ }
+ }
+
+ ret = blk_insert_bs(blk, bs, errp);
+
+ if (!ret && blk_created) {
+ if (blk_attach_dev(blk, dev) < 0) {
+ /*
+ * Shouldn't be any errors here since we just created
+ * the new blk because the device doesn't have any.
+ * Leave the message here in case blk_attach_dev is changed
+ */
+ error_setg(errp, "Can't attach drive '%s' to device '%s'",
+ str, object_get_typename(OBJECT(dev)));
+ } else {
+ *ptr = blk;
+ }
+ }
+
+ if (blk_created) {
+ blk_unref(blk);
+ }
+}
+
+static void do_parse_drive_unrealized(DeviceState *dev, const char *str,
+ void **ptr, const char *propname,
+ bool iothread, Error **errp)
{
BlockBackend *blk;
bool blk_created = false;
@@ -137,18 +184,34 @@ fail:
}
}
-static void parse_drive(DeviceState *dev, const char *str, void **ptr,
- const char *propname, Error **errp)
-{
- do_parse_drive(dev, str, ptr, propname, false, errp);
-}
-
-static void parse_drive_iothread(DeviceState *dev, const char *str, void **ptr,
+static void parse_drive_realized(DeviceState *dev, const char *str, void **ptr,
const char *propname, Error **errp)
{
- do_parse_drive(dev, str, ptr, propname, true, errp);
+ do_parse_drive_realized(dev, str, ptr, propname, false, errp);
}
+static void parse_drive_realized_iothread(DeviceState *dev, const char *str,
+ void **ptr, const char *propname,
+ Error **errp)
+{
+ do_parse_drive_realized(dev, str, ptr, propname, true, errp);
+}
+
+static void parse_drive_unrealized(DeviceState *dev, const char *str,
+ void **ptr, const char *propname,
+ Error **errp)
+{
+ do_parse_drive_unrealized(dev, str, ptr, propname, false, errp);
+}
+
+static void parse_drive_unrealized_iothread(DeviceState *dev, const char *str,
+ void **ptr, const char *propname,
+ Error **errp)
+{
+ do_parse_drive_unrealized(dev, str, ptr, propname, true, errp);
+}
+
+
static void release_drive(Object *obj, const char *name, void *opaque)
{
DeviceState *dev = DEVICE(obj);
@@ -188,13 +251,15 @@ static void get_drive(Object *obj, Visitor *v, const char
*name, void *opaque,
static void set_drive(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
- set_pointer(obj, v, opaque, NULL, parse_drive, name, errp);
+ set_pointer(obj, v, opaque, parse_drive_realized, parse_drive_unrealized,
+ name, errp);
}
static void set_drive_iothread(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
- set_pointer(obj, v, opaque, NULL, parse_drive_iothread, name, errp);
+ set_pointer(obj, v, opaque, parse_drive_realized_iothread,
+ parse_drive_unrealized_iothread, name, errp);
}
const PropertyInfo qdev_prop_drive = {
--
2.17.0
