block: call the snapshot handlers of the protocol drivers
When snapshot handlers are not defined in the format driver, it is
better to call the ones of the protocol driver. This enables us to
implement snapshot support in the protocol driver.
We need to call bdrv_close() and bdrv_open() handlers of the format
driver before and after bdrv_snapshot_goto() call of the protocol. It is
because the contents of the block driver state may need to be changed
after loading vmstate.
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index b1ef85c..cacf11b 100644
--- a/block.c
+++ b/block.c
@@ -1631,9 +1631,11 @@
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_save_vmstate)
- return -ENOTSUP;
- return drv->bdrv_save_vmstate(bs, buf, pos, size);
+ if (drv->bdrv_save_vmstate)
+ return drv->bdrv_save_vmstate(bs, buf, pos, size);
+ if (bs->file)
+ return bdrv_save_vmstate(bs->file, buf, pos, size);
+ return -ENOTSUP;
}
int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
@@ -1642,9 +1644,11 @@
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_load_vmstate)
- return -ENOTSUP;
- return drv->bdrv_load_vmstate(bs, buf, pos, size);
+ if (drv->bdrv_load_vmstate)
+ return drv->bdrv_load_vmstate(bs, buf, pos, size);
+ if (bs->file)
+ return bdrv_load_vmstate(bs->file, buf, pos, size);
+ return -ENOTSUP;
}
void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
@@ -1668,20 +1672,37 @@
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_snapshot_create)
- return -ENOTSUP;
- return drv->bdrv_snapshot_create(bs, sn_info);
+ if (drv->bdrv_snapshot_create)
+ return drv->bdrv_snapshot_create(bs, sn_info);
+ if (bs->file)
+ return bdrv_snapshot_create(bs->file, sn_info);
+ return -ENOTSUP;
}
int bdrv_snapshot_goto(BlockDriverState *bs,
const char *snapshot_id)
{
BlockDriver *drv = bs->drv;
+ int ret, open_ret;
+
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_snapshot_goto)
- return -ENOTSUP;
- return drv->bdrv_snapshot_goto(bs, snapshot_id);
+ if (drv->bdrv_snapshot_goto)
+ return drv->bdrv_snapshot_goto(bs, snapshot_id);
+
+ if (bs->file) {
+ drv->bdrv_close(bs);
+ ret = bdrv_snapshot_goto(bs->file, snapshot_id);
+ open_ret = drv->bdrv_open(bs, bs->open_flags);
+ if (open_ret < 0) {
+ bdrv_delete(bs->file);
+ bs->drv = NULL;
+ return open_ret;
+ }
+ return ret;
+ }
+
+ return -ENOTSUP;
}
int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
@@ -1689,9 +1710,11 @@
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_snapshot_delete)
- return -ENOTSUP;
- return drv->bdrv_snapshot_delete(bs, snapshot_id);
+ if (drv->bdrv_snapshot_delete)
+ return drv->bdrv_snapshot_delete(bs, snapshot_id);
+ if (bs->file)
+ return bdrv_snapshot_delete(bs->file, snapshot_id);
+ return -ENOTSUP;
}
int bdrv_snapshot_list(BlockDriverState *bs,
@@ -1700,9 +1723,11 @@
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_snapshot_list)
- return -ENOTSUP;
- return drv->bdrv_snapshot_list(bs, psn_info);
+ if (drv->bdrv_snapshot_list)
+ return drv->bdrv_snapshot_list(bs, psn_info);
+ if (bs->file)
+ return bdrv_snapshot_list(bs->file, psn_info);
+ return -ENOTSUP;
}
#define NB_SUFFIXES 4
