Re: [PATCH 2/4] NFS: replace per-net client lock by mutex
From: Myklebust, Trond
Date: Mon Feb 27 2012 - 10:01:13 EST
On Mon, 2012-02-27 at 17:49 +0400, Stanislav Kinsbursky wrote:
> Lockdep is sad otherwise, because inode mutex is taken on PipeFS dentry
> creation, which can be called on mount notification, where this per-net client
> lock is taken on clients list walk.
>
> Note: I used simple mutex instead of rw semaphore because of
> nfs_put_client->atomic_dec_and_mutex_lock() call. Probably, there is a better
> solution here.
>
> Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
>
This is overkill... We end up blocking NFSv4 callbacks while the
rpc_pipefs notifier runs through the nfs_clients creating or destroying
idmapper dentries.
Surely the rpc_pipefs_event() can take a reference to the nfs_client and
then drop the spin_lock if it sees that it needs to create or destroy a
dentry?
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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