From fca5238ef3232cd0cf4bf0457e751b3bb20912a9 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 24 Dec 2010 01:32:32 +0000 Subject: NFS: Allow walking nfs_client.cl_superblocks list outside client.c We're about to move some fields from struct nfs_client to struct nfs_server. There is a many-to-one relationship between nfs_servers and nfs_clients. After these fields are moved to the nfs_server struct, to visit all of the data in these fields that is owned by one nfs_client, code will need to visit each nfs_server on the cl_superblocks list for that nfs_client. To serialize changes to the cl_superblocks list during these little expeditions, protect the list with RCU. Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/nfs4renewd.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/nfs/nfs4renewd.c') diff --git a/fs/nfs/nfs4renewd.c b/fs/nfs/nfs4renewd.c index 72b6c580af1..cde5650ee5a 100644 --- a/fs/nfs/nfs4renewd.c +++ b/fs/nfs/nfs4renewd.c @@ -63,9 +63,14 @@ nfs4_renew_state(struct work_struct *work) ops = clp->cl_mvops->state_renewal_ops; dprintk("%s: start\n", __func__); - /* Are there any active superblocks? */ - if (list_empty(&clp->cl_superblocks)) + + rcu_read_lock(); + if (list_empty(&clp->cl_superblocks)) { + rcu_read_unlock(); goto out; + } + rcu_read_unlock(); + spin_lock(&clp->cl_lock); lease = clp->cl_lease_time; last = clp->cl_last_renewal; -- cgit v1.2.3