[RFC PATCH v2 2/3] block: call the snapshot handlers of the protocol drivers

[MORITA Kazutaka]

When snapshot handlers of the format driver is not defined, it is
better to call the ones of the protocol driver.

This enables us to implement snapshot support in the protocol driver.

Signed-off-by: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp>
---
 block.c |   48 ++++++++++++++++++++++++++++++------------------
 1 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/block.c b/block.c
index 988a94a..d1866be 100644
--- a/block.c
+++ b/block.c
@@ -1689,9 +1689,11 @@ int bdrv_save_vmstate(BlockDriverState *bs, const 
uint8_t *buf,
     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,
@@ -1700,9 +1702,11 @@ int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
     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)
@@ -1726,9 +1730,11 @@ int bdrv_snapshot_create(BlockDriverState *bs,
     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,
@@ -1737,9 +1743,11 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
     BlockDriver *drv = bs->drv;
     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)
+        return bdrv_snapshot_goto(bs->file, snapshot_id);
+    return -ENOTSUP;
 }
 
 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
@@ -1747,9 +1755,11 @@ int bdrv_snapshot_delete(BlockDriverState *bs, const 
char *snapshot_id)
     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,
@@ -1758,9 +1768,11 @@ int bdrv_snapshot_list(BlockDriverState *bs,
     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
-- 
1.5.6.5

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