nfslocalio.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
  4 * Copyright (C) 2024 NeilBrown <neilb@suse.de>
  5 */
  6#ifndef __LINUX_NFSLOCALIO_H
  7#define __LINUX_NFSLOCALIO_H
  8
  9#if IS_ENABLED(CONFIG_NFS_LOCALIO)
 10
 11#include <linux/module.h>
 12#include <linux/list.h>
 13#include <linux/uuid.h>
 14#include <linux/sunrpc/clnt.h>
 15#include <linux/sunrpc/svcauth.h>
 16#include <linux/nfs.h>
 17#include <net/net_namespace.h>
 18
 19struct nfs_client;
 20struct nfs_file_localio;
 21
 22/*
 23 * Useful to allow a client to negotiate if localio
 24 * possible with its server.
 25 *
 26 * See Documentation/filesystems/nfs/localio.rst for more detail.
 27 */
 28typedef struct {
 29	uuid_t uuid;
 30	unsigned nfs3_localio_probe_count;
 31	/* this struct is over a cacheline, avoid bouncing */
 32	spinlock_t ____cacheline_aligned lock;
 33	struct list_head list;
 34	spinlock_t *list_lock; /* nn->local_clients_lock */
 35	struct net __rcu *net; /* nfsd's network namespace */
 36	struct auth_domain *dom; /* auth_domain for localio */
 37	/* Local files to close when net is shut down or exports change */
 38	struct list_head files;
 39} nfs_uuid_t;
 40
 41void nfs_uuid_init(nfs_uuid_t *);
 42bool nfs_uuid_begin(nfs_uuid_t *);
 43void nfs_uuid_end(nfs_uuid_t *);
 44void nfs_uuid_is_local(const uuid_t *, struct list_head *, spinlock_t *,
 45		       struct net *, struct auth_domain *, struct module *);
 46
 47void nfs_localio_enable_client(struct nfs_client *clp);
 48void nfs_localio_disable_client(struct nfs_client *clp);
 49void nfs_localio_invalidate_clients(struct list_head *nn_local_clients,
 50				    spinlock_t *nn_local_clients_lock);
 51
 52/* localio needs to map filehandle -> struct nfsd_file */
 53void nfs_close_local_fh(struct nfs_file_localio *);
 54
 55struct nfsd_localio_operations {
 56	bool (*nfsd_net_try_get)(struct net *);
 57	void (*nfsd_net_put)(struct net *);
 58	struct nfsd_file *(*nfsd_open_local_fh)(struct net *,
 59						struct auth_domain *,
 60						struct rpc_clnt *,
 61						const struct cred *,
 62						const struct nfs_fh *,
 63						struct nfsd_file __rcu **pnf,
 64						const fmode_t);
 65	struct net *(*nfsd_file_put_local)(struct nfsd_file __rcu **);
 66	struct file *(*nfsd_file_file)(struct nfsd_file *);
 67	void (*nfsd_file_dio_alignment)(struct nfsd_file *,
 68					u32 *, u32 *, u32 *);
 69} ____cacheline_aligned;
 70
 71extern void nfsd_localio_ops_init(void);
 72extern const struct nfsd_localio_operations *nfs_to;
 73
 74struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *,
 75		   struct rpc_clnt *, const struct cred *,
 76		   const struct nfs_fh *, struct nfs_file_localio *,
 77		   struct nfsd_file __rcu **pnf,
 78		   const fmode_t);
 79
 80static inline void nfs_to_nfsd_net_put(struct net *net)
 81{
 82	/*
 83	 * Once reference to net (and associated nfsd_serv) is dropped, NFSD
 84	 * could be unloaded, so ensure safe return from nfsd_net_put() by
 85	 * always taking RCU.
 86	 */
 87	rcu_read_lock();
 88	nfs_to->nfsd_net_put(net);
 89	rcu_read_unlock();
 90}
 91
 92static inline void nfs_to_nfsd_file_put_local(struct nfsd_file __rcu **localio)
 93{
 94	/*
 95	 * Either *localio must be guaranteed to be non-NULL, or caller
 96	 * must prevent nfsd shutdown from completing as nfs_close_local_fh()
 97	 * does by blocking the nfs_uuid from being finally put.
 98	 */
 99	struct net *net;
100
101	net = nfs_to->nfsd_file_put_local(localio);
102
103	if (net)
104		nfs_to_nfsd_net_put(net);
105}
106
107#else   /* CONFIG_NFS_LOCALIO */
108
109struct nfs_file_localio;
110static inline void nfs_close_local_fh(struct nfs_file_localio *nfl)
111{
112}
113static inline void nfsd_localio_ops_init(void)
114{
115}
116struct nfs_client;
117static inline void nfs_localio_disable_client(struct nfs_client *clp)
118{
119}
120
121#endif  /* CONFIG_NFS_LOCALIO */
122
123#endif  /* __LINUX_NFSLOCALIO_H */