[Devel] [PATCH v2 2/4] SUNRPC: fix races on PipeFS MOUNT notifications

[Myklebust, Trond]

On Tue, 2013-06-11 at 18:39 +0400, Stanislav Kinsbursky wrote:
> Below are races, when RPC client can be created without PiepFS dentries
> 
> CPU#0					CPU#1
> -----------------------------		-----------------------------
> rpc_new_client				rpc_fill_super
> rpc_setup_pipedir
> mutex_lock(&sn->pipefs_sb_lock)
> rpc_get_sb_net == NULL
> (no per-net PipeFS superblock)
> 					sn->pipefs_sb = sb;
> 					notifier_call_chain(MOUNT)
> 					(client is not in the list)
> rpc_register_client
> (client without pipes dentries)
> 
> To fix this patch:
> 1) makes PipeFS mount notification call with pipefs_sb_lock being held.
> 2) releases pipefs_sb_lock on new SUNRPC client creation only after
> registration.
> 
> Signed-off-by: Stanislav Kinsbursky <skinsbursky at parallels.com>
> Cc: stable at vger.kernel.org

Hi Stanislav,

This isn't going to apply to the stable kernels without the cleanup
patch. Could you please reorganise this patch series so that the cleanup
comes last.

Thanks,
  Trond


-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust at netapp.com
www.netapp.com