diff mbox

[for-2.5,3/6] Add new block driver interface to add/delete a BDS's child

Message ID 1438334355-26914-4-git-send-email-wency@cn.fujitsu.com
State New
Headers show

Commit Message

Wen Congyang July 31, 2015, 9:19 a.m. UTC 
In some cases, we want to take a quorum child offline, and take
another child online.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 block.c                   | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 include/block/block.h     |  4 ++++
 include/block/block_int.h |  5 +++++
 3 files changed, 61 insertions(+)

Comments

Alberto Garcia Aug. 6, 2015, 2:33 p.m. UTC | #1 
On Fri 31 Jul 2015 11:19:12 AM CEST, Wen Congyang wrote:

> +/*
> + * Hot add/remove a BDS's child. So the user can take a child offline when
> + * it is broken and take a new child online
> + */
> +void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp)
> +{
> +
> +    if (!bs->drv || !bs->drv->bdrv_add_child) {
> +        error_setg(errp, "The BDS %s doesn't support adding a child",
> +                   bdrv_get_id_or_node_name(bs));
> +        return;
> +    }
> +
> +    bs->drv->bdrv_add_child(bs, options, errp);
> +}
> +
> +void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
> +                    Error **errp)
> +{
> +    BdrvChild *child;
> +
> +    if (!bs->drv || !bs->drv->bdrv_del_child) {
> +        error_setg(errp, "The BDS %s doesn't support removing a child",
> +                   bdrv_get_id_or_node_name(bs));
> +        return;
> +    }
> +
> +    QLIST_FOREACH(child, &bs->children, next) {
> +        if (child->bs == child_bs) {
> +            break;
> +        }
> +    }
> +
> +    if (!child) {
> +        error_setg(errp, "The BDS %s is not the BDS %s's child",
> +                   bdrv_get_id_or_node_name(child_bs),
> +                   bdrv_get_id_or_node_name(bs));
> +        return;
> +    }
> +
> +    bs->drv->bdrv_del_child(bs, child_bs, errp);
> +}

I see that bdrv_del_child() checks that the child is in bs->children,
but who takes care of putting it there in the first place?

Berto
Wen Congyang Aug. 7, 2015, 1:03 a.m. UTC | #2 
On 08/06/2015 10:33 PM, Alberto Garcia wrote:
> On Fri 31 Jul 2015 11:19:12 AM CEST, Wen Congyang wrote:
> 
>> +/*
>> + * Hot add/remove a BDS's child. So the user can take a child offline when
>> + * it is broken and take a new child online
>> + */
>> +void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp)
>> +{
>> +
>> +    if (!bs->drv || !bs->drv->bdrv_add_child) {
>> +        error_setg(errp, "The BDS %s doesn't support adding a child",
>> +                   bdrv_get_id_or_node_name(bs));
>> +        return;
>> +    }
>> +
>> +    bs->drv->bdrv_add_child(bs, options, errp);
>> +}
>> +
>> +void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
>> +                    Error **errp)
>> +{
>> +    BdrvChild *child;
>> +
>> +    if (!bs->drv || !bs->drv->bdrv_del_child) {
>> +        error_setg(errp, "The BDS %s doesn't support removing a child",
>> +                   bdrv_get_id_or_node_name(bs));
>> +        return;
>> +    }
>> +
>> +    QLIST_FOREACH(child, &bs->children, next) {
>> +        if (child->bs == child_bs) {
>> +            break;
>> +        }
>> +    }
>> +
>> +    if (!child) {
>> +        error_setg(errp, "The BDS %s is not the BDS %s's child",
>> +                   bdrv_get_id_or_node_name(child_bs),
>> +                   bdrv_get_id_or_node_name(bs));
>> +        return;
>> +    }
>> +
>> +    bs->drv->bdrv_del_child(bs, child_bs, errp);
>> +}
> 
> I see that bdrv_del_child() checks that the child is in bs->children,
> but who takes care of putting it there in the first place?

The child is opened by the function bdrv_open_image().
bdrv_open_image()
    bdrv_open_child()
        bdrv_attach_child()

Thanks
Wen Congyang

> 
> Berto
> .
>
Alberto Garcia Aug. 7, 2015, 11:52 a.m. UTC | #3 
On Fri 07 Aug 2015 03:03:07 AM CEST, Wen Congyang wrote:

>>> +void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp)
>>> +{
>>> +
>>> +    if (!bs->drv || !bs->drv->bdrv_add_child) {
>>> +        error_setg(errp, "The BDS %s doesn't support adding a child",
>>> +                   bdrv_get_id_or_node_name(bs));
>>> +        return;
>>> +    }
>>> +
>>> +    bs->drv->bdrv_add_child(bs, options, errp);
>>> +}
>>> +
>>> +void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
>>> +                    Error **errp)
>>> +{
>>> +    BdrvChild *child;
>>> +
>>> +    if (!bs->drv || !bs->drv->bdrv_del_child) {
>>> +        error_setg(errp, "The BDS %s doesn't support removing a child",
>>> +                   bdrv_get_id_or_node_name(bs));
>>> +        return;
>>> +    }
>>> +
>>> +    QLIST_FOREACH(child, &bs->children, next) {
>>> +        if (child->bs == child_bs) {
>>> +            break;
>>> +        }
>>> +    }
>>> +
>>> +    if (!child) {
>>> +        error_setg(errp, "The BDS %s is not the BDS %s's child",
>>> +                   bdrv_get_id_or_node_name(child_bs),
>>> +                   bdrv_get_id_or_node_name(bs));
>>> +        return;
>>> +    }
>>> +
>>> +    bs->drv->bdrv_del_child(bs, child_bs, errp);
>>> +}
>> 
>> I see that bdrv_del_child() checks that the child is in bs->children,
>> but who takes care of putting it there in the first place?
>
> The child is opened by the function bdrv_open_image().
> bdrv_open_image()
>     bdrv_open_child()
>         bdrv_attach_child()

I see, it's drv->bdrv_add_child() who takes care of opening the image,
this only provides the BlockdevOptions.

Thanks!

Reviewed-by: Alberto Garcia <berto@igalia.com>

Berto
Alberto Garcia Aug. 10, 2015, 8:19 a.m. UTC | #4 
On Fri 31 Jul 2015 11:19:12 AM CEST, Wen Congyang wrote:

> +static const char *bdrv_get_id_or_node_name(BlockDriverState *bs)
> +{
> +    if (bs->blk) {
> +        return blk_name(bs->blk);
> +    }
> +
> +    return bs->node_name ? bs->node_name : "";
> +}

You don't need to add this function, you can use
bdrv_get_device_or_node_name() instead.

Berto
Wen Congyang Aug. 10, 2015, 9:53 a.m. UTC | #5 
On 08/10/2015 04:19 PM, Alberto Garcia wrote:
> On Fri 31 Jul 2015 11:19:12 AM CEST, Wen Congyang wrote:
> 
>> +static const char *bdrv_get_id_or_node_name(BlockDriverState *bs)
>> +{
>> +    if (bs->blk) {
>> +        return blk_name(bs->blk);
>> +    }
>> +
>> +    return bs->node_name ? bs->node_name : "";
>> +}
> 
> You don't need to add this function, you can use
> bdrv_get_device_or_node_name() instead.

Yes, I will update it in the next version.

Thanks
Wen Congyang

> 
> Berto
> .
>
diff mbox

Patch

diff --git a/block.c b/block.c
index d088ee0..934a32d 100644
--- a/block.c
+++ b/block.c
@@ -4251,3 +4251,55 @@  BlockAcctStats *bdrv_get_stats(BlockDriverState *bs)
 {
     return &bs->stats;
 }
+
+static const char *bdrv_get_id_or_node_name(BlockDriverState *bs)
+{
+    if (bs->blk) {
+        return blk_name(bs->blk);
+    }
+
+    return bs->node_name ? bs->node_name : "";
+}
+
+/*
+ * Hot add/remove a BDS's child. So the user can take a child offline when
+ * it is broken and take a new child online
+ */
+void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp)
+{
+
+    if (!bs->drv || !bs->drv->bdrv_add_child) {
+        error_setg(errp, "The BDS %s doesn't support adding a child",
+                   bdrv_get_id_or_node_name(bs));
+        return;
+    }
+
+    bs->drv->bdrv_add_child(bs, options, errp);
+}
+
+void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
+                    Error **errp)
+{
+    BdrvChild *child;
+
+    if (!bs->drv || !bs->drv->bdrv_del_child) {
+        error_setg(errp, "The BDS %s doesn't support removing a child",
+                   bdrv_get_id_or_node_name(bs));
+        return;
+    }
+
+    QLIST_FOREACH(child, &bs->children, next) {
+        if (child->bs == child_bs) {
+            break;
+        }
+    }
+
+    if (!child) {
+        error_setg(errp, "The BDS %s is not the BDS %s's child",
+                   bdrv_get_id_or_node_name(child_bs),
+                   bdrv_get_id_or_node_name(bs));
+        return;
+    }
+
+    bs->drv->bdrv_del_child(bs, child_bs, errp);
+}
diff --git a/include/block/block.h b/include/block/block.h
index 37916f7..4a03fb6 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -616,4 +616,8 @@  void bdrv_flush_io_queue(BlockDriverState *bs);
 
 BlockAcctStats *bdrv_get_stats(BlockDriverState *bs);
 
+void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp);
+void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child,
+                    Error **errp);
+
 #endif
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 14ad4c3..b6f2905 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -288,6 +288,11 @@  struct BlockDriver {
      */
     int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
 
+    void (*bdrv_add_child)(BlockDriverState *bs, QDict *options,
+                           Error **errp);
+    void (*bdrv_del_child)(BlockDriverState *bs, BlockDriverState *child,
+                           Error **errp);
+
     QLIST_ENTRY(BlockDriver) list;
 };