[ 091/187] NFS: Force the legacy idmapper to be single threaded

Greg Kroah-Hartman
2012-07-12T23:32:24Z

From: Bryan Schumaker <bjschuma@netapp.com>

commit b1027439dff844675f6c0df97a1b1d190791a699 upstream.

It was initially coded under the assumption that there would only be one
request at a time, so use a lock to enforce this requirement..

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/idmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -57,6 +57,11 @@ unsigned int nfs_idmap_cache_timeout = 6
static const struct cred *id_resolver_cache;
static struct key_type key_type_id_resolver_legacy;

+struct idmap {
+ struct rpc_pipe *idmap_pipe;
+ struct key_construction *idmap_key_cons;
+ struct mutex idmap_mutex;
+};

/**
* nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
@@ -310,9 +315,11 @@ static ssize_t nfs_idmap_get_key(const c
name, namelen, type, data,
data_size, NULL);
if (ret < 0) {
+ mutex_lock(&idmap->idmap_mutex);
ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
name, namelen, type, data,
data_size, idmap);
+ mutex_unlock(&idmap->idmap_mutex);
}
return ret;
}
@@ -354,11 +361,6 @@ static int nfs_idmap_lookup_id(const cha
/* idmap classic begins here */
module_param(nfs_idmap_cache_timeout, int, 0644);

-struct idmap {
- struct rpc_pipe *idmap_pipe;
- struct key_construction *idmap_key_cons;
-};
-
enum {
Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
};
@@ -469,6 +471,7 @@ nfs_idmap_new(struct nfs_client *clp)
return error;
}
idmap->idmap_pipe = pipe;
+ mutex_init(&idmap->idmap_mutex);

clp->cl_idmap = idmap;
return 0;