[HARDY 1/2 ] SRU: Bug#253004 nfsd4: probe callback channel only once

[Stefan Bader]

Manoj Iyer wrote:
> SRU JUSTIFICATION:
> 
> IMPACT: Oops in sunrpc:rpc_shutdown_client
> Fix: likely related to: #212485 kernel bug rpc nfs client. Backported 
> patch to Hardy.
> TEST: Test kernel in http://people.ubuntu.com/~manjo/lp253004-hardy/ was 
> tested by community and reported to work.
> 
> 
> The following changes since commit 
> 7758896776e7991a8fe5dc62d83fae68648fdd7d:
>    Brad Figg (1):
>          UBUNTU: [Hardy SRU][SAUCE]Add information to recognize Toshiba 
> Satellite Pro M10 Alps Touchpad
> 
> are available in the git repository at:
> 
>    git://kernel.ubuntu.com/manjo/ubuntu-hardy.git lp253004
> 
> J. Bruce Fields (2):
>        nfsd: move callback rpc_client creation into separate thread
>        nfsd4: probe callback channel only once
> 
>   fs/nfsd/nfs4callback.c |   80 
> ++++++++++++++++++++++++-----------------------
>   fs/nfsd/nfs4state.c    |    3 +-
>   2 files changed, 42 insertions(+), 41 deletions(-)
> 
>>From 3011a223e977fb48696d246c2933a1fc2827dbac Mon Sep 17 00:00:00 2001
> From: J. Bruce Fields <bfields at citi.umich.edu>
> Date: Thu, 22 Nov 2007 13:54:18 -0500
> Subject: [PATCH] nfsd4: probe callback channel only once
> 
> Bug: 253004
> BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/253004
> 
> Our callback code doesn't actually handle concurrent attempts to probe
> the callback channel.  Some rethinking of the locking may be required.
> However, we can also just move the callback probing to this case.  Since
> this is the only time a client is "confirmed" (and since that can only
> happen once in the lifetime of a client), this ensures we only probe
> once.
> 
> Signed-off-by: J. Bruce Fields <bfields at citi.umich.edu>
> ---
>   fs/nfsd/nfs4callback.c |    4 ++--
>   fs/nfsd/nfs4state.c    |    3 +--
>   2 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index 698376b..a292640 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -370,8 +370,6 @@ static int do_probe_callback(void *data)
>   		.flags		= (RPC_CLNT_CREATE_NOPING),
>   	};
> 
> -	if (atomic_read(&cb->cb_set))
> -		return;
>   	struct rpc_message msg = {
>   		.rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
>   		.rpc_argp       = clp,
> @@ -379,6 +377,8 @@ static int do_probe_callback(void *data)
>   	struct rpc_clnt *client;
>   	int status;
> 
> +	BUG_ON(atomic_read(&clp->cl_callback.cb_set));
> +
>   	/* Initialize address */
>   	memset(&addr, 0, sizeof(addr));
>   	addr.sin_family = AF_INET;
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 31673cd..9d81c71 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -948,6 +948,7 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
>   			}
>   			move_to_confirmed(unconf);
>   			conf = unconf;
> +			nfsd4_probe_callback(conf);
>   			status = nfs_ok;
>   		}
>   	} else if ((!conf || (conf && !same_verf(&conf->cl_confirm, &confirm)))
> @@ -965,8 +966,6 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
>   		status = nfserr_clid_inuse;
>   	}
>   out:
> -	if (!status)
> -		nfsd4_probe_callback(conf);
>   	nfs4_unlock_state();
>   	return status;
>   }
ACK and applied

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