NFS: make nfs_match_client killable

    Actually we don't do anything with return value from
    nfs_wait_client_init_complete in nfs_match_client, as a
    consequence if we get a fatal signal and client is not
    fully initialised, we'll loop to "again" label

    This has been proven to cause soft lockups on some scenarios
    (no-carrier but configured network interfaces)

Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index e3baa9f1da76..06e8719655f0 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -284,6 +284,7 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
         struct nfs_client *clp;
         const struct sockaddr *sap = data->addr;
         struct nfs_net *nn = net_generic(data->net, nfs_net_id);
+        int error;
 
 again:
         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
@@ -296,8 +297,10 @@ again:
                 if (clp->cl_cons_state > NFS_CS_READY) {
                         refcount_inc(&clp->cl_count);
                         spin_unlock(&nn->nfs_client_lock);
-                        nfs_wait_client_init_complete(clp);
+                        error = nfs_wait_client_init_complete(clp);
                         nfs_put_client(clp);
+                        if (error < 0)
+                                return ERR_PTR(error);
                         spin_lock(&nn->nfs_client_lock);
                         goto again;
                 }
@@ -407,6 +410,8 @@ struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_init)
                 clp = nfs_match_client(cl_init);
                 if (clp) {
                         spin_unlock(&nn->nfs_client_lock);
+                        if (IS_ERR(clp))
+                                return clp;
                         if (new)
                                 new->rpc_ops->free_client(new);
                         return nfs_found_client(cl_init, clp);