Re: [Qemu-devel] [PATCH v2] more check for replaced node

[Fam Zheng]

On Wed, 07/15 09:41, Wen Congyang wrote:
> We use mirror+replace to fix quorum's broken child. bs/s->common.bs
> is quorum, and to_replace is the broken child. The new child is target_bs.
> Without this patch, the replace node can be any node, and it can be
> top BDS with BB, or another quorum's child. We just check if the broken
> child is part of the quorum BDS in this patch.
> 
> Signed-off-by: Wen Congyang <address@hidden>
> ---
>  block.c               | 5 +++--
>  block/mirror.c        | 3 ++-
>  blockdev.c            | 2 +-
>  include/block/block.h | 3 ++-
>  4 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/block.c b/block.c
> index d088ee0..090923c 100644
> --- a/block.c
> +++ b/block.c
> @@ -4077,7 +4077,8 @@ bool bdrv_is_first_non_filter(BlockDriverState 
> *candidate)
>      return false;
>  }
>  
> -BlockDriverState *check_to_replace_node(const char *node_name, Error **errp)
> +BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
> +                                        const char *node_name, Error **errp)
>  {
>      BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
>      AioContext *aio_context;
> @@ -4100,7 +4101,7 @@ BlockDriverState *check_to_replace_node(const char 
> *node_name, Error **errp)
>       * Another benefit is that this tests exclude backing files which are
>       * blocked by the backing blockers.
>       */
> -    if (!bdrv_is_first_non_filter(to_replace_bs)) {
> +    if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
>          error_setg(errp, "Only top most non filter can be replaced");
>          to_replace_bs = NULL;
>          goto out;
> diff --git a/block/mirror.c b/block/mirror.c
> index 238a070..b81077e 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -626,7 +626,8 @@ static void mirror_complete(BlockJob *job, Error **errp)
>      if (s->replaces) {
>          AioContext *replace_aio_context;
>  
> -        s->to_replace = check_to_replace_node(s->replaces, &local_err);
> +        s->to_replace = check_to_replace_node(s->common.bs, s->replaces,
> +                                              &local_err);

Why is the check in qmp_drive_mirror not enough? Isn't this redundant?

Fam

>          if (!s->to_replace) {
>              error_propagate(errp, local_err);
>              return;
> diff --git a/blockdev.c b/blockdev.c
> index c11611d..bf12e2e 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2757,7 +2757,7 @@ void qmp_drive_mirror(const char *device, const char 
> *target,
>              goto out;
>          }
>  
> -        to_replace_bs = check_to_replace_node(replaces, &local_err);
> +        to_replace_bs = check_to_replace_node(bs, replaces, &local_err);
>  
>          if (!to_replace_bs) {
>              error_propagate(errp, local_err);
> diff --git a/include/block/block.h b/include/block/block.h
> index 37916f7..608cd4e 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -317,7 +317,8 @@ bool bdrv_recurse_is_first_non_filter(BlockDriverState 
> *bs,
>  bool bdrv_is_first_non_filter(BlockDriverState *candidate);
>  
>  /* check if a named node can be replaced when doing drive-mirror */
> -BlockDriverState *check_to_replace_node(const char *node_name, Error **errp);
> +BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
> +                                        const char *node_name, Error **errp);
>  
>  /* async block I/O */
>  typedef void BlockDriverDirtyHandler(BlockDriverState *bs, int64_t sector,
> -- 
> 2.4.3
>