NFSv4: Clean up the legacy idmapper upcall

Replace the BUG_ON(idmap->idmap_key_cons != NULL) with a
WARN_ON_ONCE(). Then get rid of the ACCESS_ONCE(idmap->idmap_key_cons).

Then add helper functions for starting, finishing and aborting the
legacy upcall.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 79f6424aa0819b7a56d0835d1d2418c9ea703b4d..8222ad861456458dcf17971fb3ade26beda95287 100644 (file)
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -330,7 +330,6 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
                ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
                                            name, namelen, type, data,
                                            data_size, idmap);
-               idmap->idmap_key_cons = NULL;
                mutex_unlock(&idmap->idmap_mutex);
        }
        return ret;
@@ -662,6 +661,34 @@ out:
        return ret;
 }
 
+static bool
+nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
+               struct key_construction *cons)
+{
+       if (idmap->idmap_key_cons != NULL) {
+               WARN_ON_ONCE(1);
+               return false;
+       }
+       idmap->idmap_key_cons = cons;
+       return true;
+}
+
+static void
+nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
+{
+       struct key_construction *cons = idmap->idmap_key_cons;
+
+       idmap->idmap_key_cons = NULL;
+       complete_request_key(cons, ret);
+}
+
+static void
+nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
+{
+       if (idmap->idmap_key_cons != NULL)
+               nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+}
+
 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
                                   const char *op,
                                   void *aux)
@@ -686,21 +713,17 @@ static int nfs_idmap_legacy_upcall(struct key_construction *cons,
        if (ret < 0)
                goto out2;
 
-       if (idmap->idmap_key_cons != NULL) {
-               WARN_ON_ONCE(1);
-               ret = -EAGAIN;
+       ret = -EAGAIN;
+       if (!nfs_idmap_prepare_pipe_upcall(idmap, cons))
                goto out2;
-       }
-       idmap->idmap_key_cons = cons;
 
        ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
-       if (ret < 0)
-               goto out3;
+       if (ret < 0) {
+               nfs_idmap_abort_pipe_upcall(idmap, ret);
+               kfree(data);
+       }
 
        return ret;
-
-out3:
-       idmap->idmap_key_cons = NULL;
 out2:
        kfree(data);
 out1:
@@ -741,14 +764,15 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
        struct key_construction *cons;
        struct idmap_msg im;
        size_t namelen_in;
-       int ret;
+       int ret = -ENOKEY;
 
        /* If instantiation is successful, anyone waiting for key construction
         * will have been woken up and someone else may now have used
         * idmap_key_cons - so after this point we may no longer touch it.
         */
        cons = idmap->idmap_key_cons;
-       idmap->idmap_key_cons = NULL;
+       if (cons == NULL)
+               goto out_noupcall;
 
        if (mlen != sizeof(im)) {
                ret = -ENOSPC;
@@ -778,7 +802,8 @@ idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
        }
 
 out:
-       complete_request_key(cons, ret);
+       nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
+out_noupcall:
        return ret;
 }
 
@@ -789,12 +814,9 @@ idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
                        struct idmap_legacy_upcalldata,
                        pipe_msg);
        struct idmap *idmap = data->idmap;
-       struct key_construction *cons;
-       if (msg->errno) {
-               cons = idmap->idmap_key_cons;
-               idmap->idmap_key_cons = NULL;
-               complete_request_key(cons, msg->errno);
-       }
+
+       if (msg->errno)
+               nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
        /* Free memory allocated in nfs_idmap_legacy_upcall() */
        kfree(data);
 }
@@ -804,7 +826,8 @@ idmap_release_pipe(struct inode *inode)
 {
        struct rpc_inode *rpci = RPC_I(inode);
        struct idmap *idmap = (struct idmap *)rpci->private;
-       idmap->idmap_key_cons = NULL;
+
+       nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
 }
 
 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)