NFS: make nfs_match_client killable

[ Upstream commit 950a578c6128c2886e295b9c7ecb0b6b22fcc92b ]

    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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 751ca65..846d45c 100644 (file)
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -290,6 +290,7 @@ 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) {
@@ -302,8 +303,10 @@ 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;
                }
@@ -413,6 +416,8 @@ 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);