RE: [PATCH v5 1/4] block/replication.c: Ignore requests after failover

[Zhang, Chen]

> -----Original Message-----
> From: Lukas Straub <address@hidden>
> Sent: Monday, September 16, 2019 3:20 AM
> To: qemu-devel <address@hidden>
> Cc: Zhang, Chen <address@hidden>; Jason Wang
> <address@hidden>; Wen Congyang <address@hidden>;
> Xie Changlong <address@hidden>; address@hidden;
> address@hidden
> Subject: [PATCH v5 1/4] block/replication.c: Ignore requests after failover
> 
> After failover the Secondary side of replication shouldn't change state,
> because it now functions as our primary disk.
> 
> In replication_start, replication_do_checkpoint, replication_stop, ignore the
> request if current state is BLOCK_REPLICATION_DONE (sucessful failover) or
> BLOCK_REPLICATION_FAILOVER (failover in progres i.e. currently merging
> active and hidden images into the base image).
> 

It looks good for me, and this patch works well in COLO continuous backup 
status in my tests.
Reviewed-by: Zhang Chen <address@hidden>

But I think this patch still need reviewed by Xie Changlong  or  Kevin Wolf.

Thanks
Zhang Chen

> Signed-off-by: Lukas Straub <address@hidden>
> ---
>  block/replication.c | 38 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 35 insertions(+), 3 deletions(-)
> 
> diff --git a/block/replication.c b/block/replication.c index
> 3d4dedddfc..97cc65c0cf 100644
> --- a/block/replication.c
> +++ b/block/replication.c
> @@ -454,6 +454,17 @@ static void replication_start(ReplicationState *rs,
> ReplicationMode mode,
>      aio_context_acquire(aio_context);
>      s = bs->opaque;
> 
> +    if (s->stage == BLOCK_REPLICATION_DONE ||
> +        s->stage == BLOCK_REPLICATION_FAILOVER) {
> +        /*
> +         * This case happens when a secondary is promoted to primary.
> +         * Ignore the request because the secondary side of replication
> +         * doesn't have to do anything anymore.
> +         */
> +        aio_context_release(aio_context);
> +        return;
> +    }
> +
>      if (s->stage != BLOCK_REPLICATION_NONE) {
>          error_setg(errp, "Block replication is running or done");
>          aio_context_release(aio_context); @@ -529,8 +540,7 @@ static void
> replication_start(ReplicationState *rs, ReplicationMode mode,
>                     "Block device is in use by internal backup job");
> 
>          top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
> -        if (!top_bs || !bdrv_is_root_node(top_bs) ||
> -            !check_top_bs(top_bs, bs)) {
> +        if (!top_bs || !check_top_bs(top_bs, bs)) {
>              error_setg(errp, "No top_bs or it is invalid");
>              reopen_backing_file(bs, false, NULL);
>              aio_context_release(aio_context); @@ -577,6 +587,17 @@ static 
> void
> replication_do_checkpoint(ReplicationState *rs, Error **errp)
>      aio_context_acquire(aio_context);
>      s = bs->opaque;
> 
> +    if (s->stage == BLOCK_REPLICATION_DONE ||
> +        s->stage == BLOCK_REPLICATION_FAILOVER) {
> +        /*
> +         * This case happens when a secondary was promoted to primary.
> +         * Ignore the request because the secondary side of replication
> +         * doesn't have to do anything anymore.
> +         */
> +        aio_context_release(aio_context);
> +        return;
> +    }
> +
>      if (s->mode == REPLICATION_MODE_SECONDARY) {
>          secondary_do_checkpoint(s, errp);
>      }
> @@ -593,7 +614,7 @@ static void replication_get_error(ReplicationState *rs,
> Error **errp)
>      aio_context_acquire(aio_context);
>      s = bs->opaque;
> 
> -    if (s->stage != BLOCK_REPLICATION_RUNNING) {
> +    if (s->stage == BLOCK_REPLICATION_NONE) {
>          error_setg(errp, "Block replication is not running");
>          aio_context_release(aio_context);
>          return;
> @@ -635,6 +656,17 @@ static void replication_stop(ReplicationState *rs,
> bool failover, Error **errp)
>      aio_context_acquire(aio_context);
>      s = bs->opaque;
> 
> +    if (s->stage == BLOCK_REPLICATION_DONE ||
> +        s->stage == BLOCK_REPLICATION_FAILOVER) {
> +        /*
> +         * This case happens when a secondary was promoted to primary.
> +         * Ignore the request because the secondary side of replication
> +         * doesn't have to do anything anymore.
> +         */
> +        aio_context_release(aio_context);
> +        return;
> +    }
> +
>      if (s->stage != BLOCK_REPLICATION_RUNNING) {
>          error_setg(errp, "Block replication is not running");
>          aio_context_release(aio_context);
> --
> 2.20.1