NFS: Return error code from nfs_callback_up() to user space

If the kernel cannot start the NFSv4 callback service during a mount
request, it returns -ENOMEM to user space, resulting in this message:

   mount.nfs4: Cannot allocate memory

Adjust nfs_alloc_client() and nfs_get_client() to pass NFSv4 callback
start-up errors back to user space so a less mysterious error message
can be displayed by the mount command.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 75c9cd2aa119..0e9a1f9743b0 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -114,6 +114,7 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
 {
         struct nfs_client *clp;
         struct rpc_cred *cred;
+        int err = -ENOMEM;
 
         if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
                 goto error_0;
@@ -121,7 +122,8 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
         clp->rpc_ops = cl_init->rpc_ops;
 
         if (cl_init->rpc_ops->version == 4) {
-                if (nfs_callback_up() < 0)
+                err = nfs_callback_up();
+                if (err < 0)
                         goto error_2;
                 __set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
         }
@@ -133,6 +135,7 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
         clp->cl_addrlen = cl_init->addrlen;
 
         if (cl_init->hostname) {
+                err = -ENOMEM;
                 clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
                 if (!clp->cl_hostname)
                         goto error_3;
@@ -165,7 +168,7 @@ error_3:
 error_2:
         kfree(clp);
 error_0:
-        return NULL;
+        return ERR_PTR(err);
 }
 
 static void nfs4_shutdown_client(struct nfs_client *clp)
@@ -456,9 +459,10 @@ static struct nfs_client *nfs_get_client(const struct nfs_client_initdata *cl_in
                 spin_unlock(&nfs_client_lock);
 
                 new = nfs_alloc_client(cl_init);
-        } while (new);
+        } while (!IS_ERR(new));
 
-        return ERR_PTR(-ENOMEM);
+        dprintk("--> nfs_get_client() = %ld [failed]\n", PTR_ERR(new));
+        return new;
 
         /* install a new client and return with it unready */
 install_client: