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Re: [Qemu-block] [PATCH v5 1/4] Add new block driver interface to add/de
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-block] [PATCH v5 1/4] Add new block driver interface to add/delete a BDS's child |
Date: |
Thu, 8 Oct 2015 19:44:33 +0100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* Wen Congyang (address@hidden) wrote:
> On 10/08/2015 03:00 AM, Dr. David Alan Gilbert wrote:
> > * Wen Congyang (address@hidden) wrote:
> >> In some cases, we want to take a quorum child offline, and take
> >> another child online.
> >
> > Hi,
> > Have you checked the output of 'info block' after adding/deleting a child?
> > I'm using one of your older worlds (from a few months ago) and I found I had
> > to add a
> >
> > bdrv_refresh_filename(bs);
> >
> > to get the output of 'info block' to show the new child.
> > I don't see it in this version.
>
> Max sent a patch series to drop BDS.filename, so I don't call
> bdrv_refresh_filename()
> here. If the BDS is not the top BDS, 'info block' still shows the wrong child.
Ah, so I guess you can just implement the exact_filename() function and that
will get it right?
Dave
>
> Thanks
> Wen Congyang
>
> >
> > Dave
> >
> >
> >>
> >> Signed-off-by: Wen Congyang <address@hidden>
> >> Signed-off-by: zhanghailiang <address@hidden>
> >> Signed-off-by: Gonglei <address@hidden>
> >> Reviewed-by: Eric Blake <address@hidden>
> >> ---
> >> block.c | 50
> >> +++++++++++++++++++++++++++++++++++++++++++++++
> >> include/block/block.h | 5 +++++
> >> include/block/block_int.h | 5 +++++
> >> 3 files changed, 60 insertions(+)
> >>
> >> diff --git a/block.c b/block.c
> >> index e815d73..1b25e43 100644
> >> --- a/block.c
> >> +++ b/block.c
> >> @@ -4265,3 +4265,53 @@ BlockAcctStats *bdrv_get_stats(BlockDriverState *bs)
> >> {
> >> return &bs->stats;
> >> }
> >> +
> >> +/*
> >> + * 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 *parent_bs, BlockDriverState
> >> *child_bs,
> >> + Error **errp)
> >> +{
> >> +
> >> + if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
> >> + error_setg(errp, "The BDS %s doesn't support adding a child",
> >> + bdrv_get_device_or_node_name(parent_bs));
> >> + return;
> >> + }
> >> +
> >> + if (!QLIST_EMPTY(&child_bs->parents)) {
> >> + error_setg(errp, "The BDS %s already has parent",
> >> + child_bs->node_name);
> >> + return;
> >> + }
> >> +
> >> + parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
> >> +}
> >> +
> >> +void bdrv_del_child(BlockDriverState *parent_bs, BlockDriverState
> >> *child_bs,
> >> + Error **errp)
> >> +{
> >> + BdrvChild *child;
> >> +
> >> + if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
> >> + error_setg(errp, "The BDS %s doesn't support removing a child",
> >> + bdrv_get_device_or_node_name(parent_bs));
> >> + return;
> >> + }
> >> +
> >> + QLIST_FOREACH(child, &parent_bs->children, next) {
> >> + if (child->bs == child_bs) {
> >> + break;
> >> + }
> >> + }
> >> +
> >> + if (!child) {
> >> + error_setg(errp, "BDS %s is not a child of %s",
> >> + bdrv_get_device_or_node_name(child_bs),
> >> + bdrv_get_device_or_node_name(parent_bs));
> >> + return;
> >> + }
> >> +
> >> + parent_bs->drv->bdrv_del_child(parent_bs, child_bs, errp);
> >> +}
> >> diff --git a/include/block/block.h b/include/block/block.h
> >> index ef67353..665c56f 100644
> >> --- a/include/block/block.h
> >> +++ b/include/block/block.h
> >> @@ -616,4 +616,9 @@ void bdrv_flush_io_queue(BlockDriverState *bs);
> >>
> >> BlockAcctStats *bdrv_get_stats(BlockDriverState *bs);
> >>
> >> +void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
> >> + Error **errp);
> >> +void bdrv_del_child(BlockDriverState *parent, BlockDriverState *child,
> >> + Error **errp);
> >> +
> >> #endif
> >> diff --git a/include/block/block_int.h b/include/block/block_int.h
> >> index 2f2c47b..64cbc55 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 *parent, BlockDriverState
> >> *child,
> >> + Error **errp);
> >> + void (*bdrv_del_child)(BlockDriverState *parent, BlockDriverState
> >> *child,
> >> + Error **errp);
> >> +
> >> QLIST_ENTRY(BlockDriver) list;
> >> };
> >>
> >> --
> >> 2.4.3
> >>
> > --
> > Dr. David Alan Gilbert / address@hidden / Manchester, UK
> > .
> >
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK