Re: [PATCH 1/3] Debug: Add WARN'ing messages for when a client has opened/closed connection.

[Prerna <saxenap.ltc@xxxxxxxxx>]

I looked through what you were suggesting.

I was assuming virNetSocketGetFD()would do a NULL check for the sock arg, and would return immediately if a different client executed a virNetServerClientClose() setting client->sock to null.

Since this check is missing, I understand the implicit assumption is to always have virNetServerClientGetFD() lock the client, and consequently, I will rearrange debug messages around to prevent lock contention.

Sending out a V2.

On Wed, Mar 22, 2017 at 1:41 PM, Peter Krempa <pkrempa@xxxxxxxxxx> wrote:

On Wed, Mar 22, 2017 at 01:02:17 -0700, Prerna Saxena wrote:
> While tracing connections from a remote client, it helps to keep track
> of the connection lifecycle. Messages such as the following :
>
> error : virNetSocketReadWire:1574 : End of file while reading data: Input/output error
>
> are rather unhelpful. They do not indicate if the client had earlier asked for
> connection closure via libvirt API.
> This patch introduces messages to annotate when a client connected/disconnected.
>
> Signed-off-by: Prerna Saxena <saxenap.ltc@xxxxxxxxx>
> ---
>  src/rpc/virnetserverclient.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/src/rpc/virnetserverclient.c b/src/rpc/virnetserverclient.c
> index 85857bc..a77feaa 100644
> --- a/src/rpc/virnetserverclient.c
> +++ b/src/rpc/virnetserverclient.c
> @@ -678,14 +678,19 @@ int virNetServerClientGetTLSKeySize(virNetServerClientPtr client)
>      return size;
>  }
>  #endif
> -
> +/*
> + * This mostly just needs to publish the client socket FD to logs.
> + * It does not necessarily need a lock, or will add lock contention problems.
> + * Replace the lock with a reference counting mechanism, to prevent the client
> + * object from being deallocated while this is being run
> + */
>  int virNetServerClientGetFD(virNetServerClientPtr client)
>  {
>      int fd = -1;
> -    virObjectLock(client);
> +    virObjectRef(client);
>      if (client->sock)
>          fd = virNetSocketGetFD(client->sock);
> -    virObjectUnlock(client);
> +    virObjectUnref(client);

This change is not justified in any way. Also looks wrong. You can't
access an unlocked object.

>      return fd;
>  }
>
> @@ -965,7 +970,9 @@ void virNetServerClientClose(virNetServerClientPtr client)
>      virKeepAlivePtr ka;
>
>      virObjectLock(client);
> -    VIR_DEBUG("client=%p", client);
> +    VIR_WARN("Free'ing up resources for client=%p sock=%d", client,
> +               virNetServerClientGetFD(client));

NACK using warnings instead of debug messages is not desired. For debug
purposes you should use debug logs.

--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list