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NFS: Allow walking nfs_client.cl_superblocks list outside client.c

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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 <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Chuck Lever 2010-12-24 01:32:32 +00:00 • committed by Trond Myklebust
commit fca5238ef3
2 changed files with 32 additions and 21 deletions
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44
fs/nfs/client.c
View file

@ -1003,6 +1003,27 @@ static void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_serve
target->options = source->options;
}
static void nfs_server_insert_lists(struct nfs_server *server)
{
struct nfs_client *clp = server->nfs_client;
spin_lock(&nfs_client_lock);
list_add_tail_rcu(&server->client_link, &clp->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
spin_unlock(&nfs_client_lock);
}
static void nfs_server_remove_lists(struct nfs_server *server)
{
spin_lock(&nfs_client_lock);
list_del_rcu(&server->client_link);
list_del(&server->master_link);
spin_unlock(&nfs_client_lock);
synchronize_rcu();
}
/*
* Allocate and initialise a server record
*/
@ -1046,11 +1067,8 @@ void nfs_free_server(struct nfs_server *server)
{
dprintk("--> nfs_free_server()\n");
nfs_server_remove_lists(server);
unset_pnfs_layoutdriver(server);
spin_lock(&nfs_client_lock);
list_del(&server->client_link);
list_del(&server->master_link);
spin_unlock(&nfs_client_lock);
if (server->destroy != NULL)
server->destroy(server);
@ -1125,11 +1143,7 @@ struct nfs_server *nfs_create_server(const struct nfs_parsed_mount_data *data,
(unsigned long long) server->fsid.major,
(unsigned long long) server->fsid.minor);
spin_lock(&nfs_client_lock);
list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
spin_unlock(&nfs_client_lock);
nfs_server_insert_lists(server);
server->mount_time = jiffies;
nfs_free_fattr(fattr);
return server;
@ -1454,11 +1468,7 @@ static int nfs4_server_common_setup(struct nfs_server *server,
if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)
server->namelen = NFS4_MAXNAMLEN;
spin_lock(&nfs_client_lock);
list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
spin_unlock(&nfs_client_lock);
nfs_server_insert_lists(server);
server->mount_time = jiffies;
out:
nfs_free_fattr(fattr);
@ -1663,11 +1673,7 @@ struct nfs_server *nfs_clone_server(struct nfs_server *source,
if (error < 0)
goto out_free_server;
spin_lock(&nfs_client_lock);
list_add_tail(&server->client_link, &server->nfs_client->cl_superblocks);
list_add_tail(&server->master_link, &nfs_volume_list);
spin_unlock(&nfs_client_lock);
nfs_server_insert_lists(server);
server->mount_time = jiffies;
nfs_free_fattr(fattr_fsinfo);

9
fs/nfs/nfs4renewd.c
View file

@ -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;