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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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c25a89770d
Instead of calling xchg() and unrcu_pointer() before
nfsd_file_put_local(), we now pass pointer to the __rcu pointer and call
xchg() and unrcu_pointer() inside that function.
Where unrcu_pointer() is currently called the internals of "struct
nfsd_file" are not known and that causes older compilers such as gcc-8
to complain.
In some cases we have a __kernel (aka normal) pointer not an __rcu
pointer so we need to cast it to __rcu first. This is strictly a
weakening so no information is lost. Somewhat surprisingly, this cast
is accepted by gcc-8.
This has the pleasing result that the cmpxchg() which sets ro_file and
rw_file, and also the xchg() which clears them, are both now in the nfsd
code.
Reported-by: Pali Rohár <pali@kernel.org>
Reported-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Fixes: 86e0041225 ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
123 lines
3.5 KiB
C
123 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
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* Copyright (C) 2024 NeilBrown <neilb@suse.de>
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*/
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#ifndef __LINUX_NFSLOCALIO_H
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#define __LINUX_NFSLOCALIO_H
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#if IS_ENABLED(CONFIG_NFS_LOCALIO)
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/uuid.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/svcauth.h>
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#include <linux/nfs.h>
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#include <net/net_namespace.h>
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struct nfs_client;
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struct nfs_file_localio;
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/*
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* Useful to allow a client to negotiate if localio
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* possible with its server.
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*
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* See Documentation/filesystems/nfs/localio.rst for more detail.
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*/
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typedef struct {
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uuid_t uuid;
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unsigned nfs3_localio_probe_count;
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/* this struct is over a cacheline, avoid bouncing */
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spinlock_t ____cacheline_aligned lock;
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struct list_head list;
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spinlock_t *list_lock; /* nn->local_clients_lock */
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struct net __rcu *net; /* nfsd's network namespace */
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struct auth_domain *dom; /* auth_domain for localio */
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/* Local files to close when net is shut down or exports change */
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struct list_head files;
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} nfs_uuid_t;
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void nfs_uuid_init(nfs_uuid_t *);
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bool nfs_uuid_begin(nfs_uuid_t *);
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void nfs_uuid_end(nfs_uuid_t *);
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void nfs_uuid_is_local(const uuid_t *, struct list_head *, spinlock_t *,
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struct net *, struct auth_domain *, struct module *);
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void nfs_localio_enable_client(struct nfs_client *clp);
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void nfs_localio_disable_client(struct nfs_client *clp);
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void nfs_localio_invalidate_clients(struct list_head *nn_local_clients,
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spinlock_t *nn_local_clients_lock);
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/* localio needs to map filehandle -> struct nfsd_file */
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void nfs_close_local_fh(struct nfs_file_localio *);
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struct nfsd_localio_operations {
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bool (*nfsd_net_try_get)(struct net *);
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void (*nfsd_net_put)(struct net *);
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struct nfsd_file *(*nfsd_open_local_fh)(struct net *,
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struct auth_domain *,
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struct rpc_clnt *,
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const struct cred *,
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const struct nfs_fh *,
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struct nfsd_file __rcu **pnf,
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const fmode_t);
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struct net *(*nfsd_file_put_local)(struct nfsd_file __rcu **);
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struct nfsd_file *(*nfsd_file_get_local)(struct nfsd_file *);
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struct file *(*nfsd_file_file)(struct nfsd_file *);
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} ____cacheline_aligned;
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extern void nfsd_localio_ops_init(void);
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extern const struct nfsd_localio_operations *nfs_to;
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struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *,
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struct rpc_clnt *, const struct cred *,
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const struct nfs_fh *, struct nfs_file_localio *,
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struct nfsd_file __rcu **pnf,
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const fmode_t);
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static inline void nfs_to_nfsd_net_put(struct net *net)
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{
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/*
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* Once reference to net (and associated nfsd_serv) is dropped, NFSD
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* could be unloaded, so ensure safe return from nfsd_net_put() by
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* always taking RCU.
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*/
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rcu_read_lock();
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nfs_to->nfsd_net_put(net);
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rcu_read_unlock();
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}
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static inline void nfs_to_nfsd_file_put_local(struct nfsd_file __rcu **localio)
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{
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/*
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* Either *localio must be guaranteed to be non-NULL, or caller
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* must prevent nfsd shutdown from completing as nfs_close_local_fh()
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* does by blocking the nfs_uuid from being finally put.
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*/
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struct net *net;
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net = nfs_to->nfsd_file_put_local(localio);
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if (net)
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nfs_to_nfsd_net_put(net);
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}
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#else /* CONFIG_NFS_LOCALIO */
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struct nfs_file_localio;
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static inline void nfs_close_local_fh(struct nfs_file_localio *nfl)
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{
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}
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static inline void nfsd_localio_ops_init(void)
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{
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}
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struct nfs_client;
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static inline void nfs_localio_disable_client(struct nfs_client *clp)
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{
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}
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#endif /* CONFIG_NFS_LOCALIO */
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#endif /* __LINUX_NFSLOCALIO_H */
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