Re: [Qemu-block] [PATCH v2 07/16] block: Convert bs->backing_hd to BdrvChild

[Alberto Garcia]

On Thu 01 Oct 2015 03:13:25 PM CEST, Kevin Wolf wrote:
> This is the final step in converting all of the BlockDriverState
> pointers that block drivers use to BdrvChild.
>
> After this patch, bs->children contains the full list of child nodes
> that are referenced by a given BDS, and these children are only
> referenced through BdrvChild, so that updating the pointer in there is
> enough for changing edges in the graph.
>
> Signed-off-by: Kevin Wolf 

Reviewed-by: Alberto Garcia 

Berto

Re: [Qemu-block] [PATCH v2 07/16] block: Convert bs->backing_hd to BdrvChild

[Max Reitz]

On 01.10.2015 15:13, Kevin Wolf wrote:
> This is the final step in converting all of the BlockDriverState
> pointers that block drivers use to BdrvChild.
> 
> After this patch, bs->children contains the full list of child nodes
> that are referenced by a given BDS, and these children are only
> referenced through BdrvChild, so that updating the pointer in there is
> enough for changing edges in the graph.
> 
> Signed-off-by: Kevin Wolf 
> ---
>  block.c   | 116 
> +-
>  block/io.c|  24 +-
>  block/mirror.c|   6 +--
>  block/qapi.c  |   8 ++--
>  block/qcow.c  |   4 +-
>  block/qcow2-cluster.c |   4 +-
>  block/qcow2.c |   6 +--
>  block/qed.c   |  12 ++---
>  block/stream.c|   8 ++--
>  block/vmdk.c  |  21 +
>  block/vvfat.c |   6 +--
>  blockdev.c|   4 +-
>  include/block/block_int.h |  12 +++--
>  qemu-img.c|   4 +-
>  14 files changed, 125 insertions(+), 110 deletions(-)

Reviewed-by: Max Reitz 



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[Qemu-block] [PATCH v2 07/16] block: Convert bs->backing_hd to BdrvChild

[Kevin Wolf]

This is the final step in converting all of the BlockDriverState
pointers that block drivers use to BdrvChild.

After this patch, bs->children contains the full list of child nodes
that are referenced by a given BDS, and these children are only
referenced through BdrvChild, so that updating the pointer in there is
enough for changing edges in the graph.

Signed-off-by: Kevin Wolf 
---
 block.c   | 116 +-
 block/io.c|  24 +-
 block/mirror.c|   6 +--
 block/qapi.c  |   8 ++--
 block/qcow.c  |   4 +-
 block/qcow2-cluster.c |   4 +-
 block/qcow2.c |   6 +--
 block/qed.c   |  12 ++---
 block/stream.c|   8 ++--
 block/vmdk.c  |  21 +
 block/vvfat.c |   6 +--
 blockdev.c|   4 +-
 include/block/block_int.h |  12 +++--
 qemu-img.c|   4 +-
 14 files changed, 125 insertions(+), 110 deletions(-)

diff --git a/block.c b/block.c
index 33ecd93..20a3c5c 100644
--- a/block.c
+++ b/block.c
@@ -721,7 +721,7 @@ const BdrvChildRole child_format = {
 };
 
 /*
- * Returns the flags that bs->backing_hd should get, based on the given flags
+ * Returns the flags that bs->backing should get, based on the given flags
  * for the parent BDS
  */
 static int bdrv_backing_flags(int flags)
@@ -1115,32 +1115,31 @@ void bdrv_unref_child(BlockDriverState *parent, 
BdrvChild *child)
 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
 {
 
-if (bs->backing_hd) {
+if (bs->backing) {
 assert(bs->backing_blocker);
-bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
-bdrv_detach_child(bs->backing_child);
+bdrv_op_unblock_all(bs->backing->bs, bs->backing_blocker);
+bdrv_detach_child(bs->backing);
 } else if (backing_hd) {
 error_setg(>backing_blocker,
"node is used as backing hd of '%s'",
bdrv_get_device_or_node_name(bs));
 }
 
-bs->backing_hd = backing_hd;
 if (!backing_hd) {
 error_free(bs->backing_blocker);
 bs->backing_blocker = NULL;
-bs->backing_child = NULL;
+bs->backing = NULL;
 goto out;
 }
-bs->backing_child = bdrv_attach_child(bs, backing_hd, _backing);
+bs->backing = bdrv_attach_child(bs, backing_hd, _backing);
 bs->open_flags &= ~BDRV_O_NO_BACKING;
 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
 pstrcpy(bs->backing_format, sizeof(bs->backing_format),
 backing_hd->drv ? backing_hd->drv->format_name : "");
 
-bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);
+bdrv_op_block_all(backing_hd, bs->backing_blocker);
 /* Otherwise we won't be able to commit due to check in bdrv_commit */
-bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
+bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
 bs->backing_blocker);
 out:
 bdrv_refresh_limits(bs, NULL);
@@ -1161,7 +1160,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict 
*options, Error **errp)
 BlockDriverState *backing_hd;
 Error *local_err = NULL;
 
-if (bs->backing_hd != NULL) {
+if (bs->backing != NULL) {
 QDECREF(options);
 goto free_exit;
 }
@@ -1201,7 +1200,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict 
*options, Error **errp)
 qdict_put(options, "driver", qstring_from_str(bs->backing_format));
 }
 
-assert(bs->backing_hd == NULL);
+assert(bs->backing == NULL);
 ret = bdrv_open_inherit(_hd,
 *backing_filename ? backing_filename : NULL,
 NULL, options, 0, bs, _backing, _err);
@@ -1892,8 +1891,8 @@ void bdrv_close(BlockDriverState *bs)
 bs->drv->bdrv_close(bs);
 bs->drv = NULL;
 
-if (bs->backing_hd) {
-BlockDriverState *backing_hd = bs->backing_hd;
+if (bs->backing) {
+BlockDriverState *backing_hd = bs->backing->bs;
 bdrv_set_backing_hd(bs, NULL);
 bdrv_unref(backing_hd);
 }
@@ -2205,20 +2204,20 @@ int bdrv_commit(BlockDriverState *bs)
 if (!drv)
 return -ENOMEDIUM;
 
-if (!bs->backing_hd) {
+if (!bs->backing) {
 return -ENOTSUP;
 }
 
 if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
-bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) 
{
+bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, 
NULL)) {
 return -EBUSY;
 }
 
-ro = bs->backing_hd->read_only;
-open_flags =  bs->backing_hd->open_flags;
+ro = bs->backing->bs->read_only;
+open_flags =  bs->backing->bs->open_flags;
 
 if (ro) {
-if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) {
+if