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bc29408695
Fix the possibility of racing nfs_local_probe() resulting in: list_add double add: new=ffff8b99707f9f58, prev=ffff8b99707f9f58, next=ffffffffc0f30000. ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:35! Add nfs_uuid_init() to properly initialize all nfs_uuid_t members (particularly its list_head). Switch to returning bool from nfs_uuid_begin(), returns false if nfs_uuid_t is already in-use (its list_head is on a list). Update nfs_local_probe() to return early if the nfs_client's cl_uuid (nfs_uuid_t) is in-use. Also, switch nfs_uuid_begin() from using list_add_tail_rcu() to list_add_tail() -- rculist was used in an earlier version of the localio code that had a lockless nfs_uuid_lookup interface. Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
91 lines
2.6 KiB
C
91 lines
2.6 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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/* nfsd_file structure is purposely kept opaque to NFS client */
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struct nfsd_file;
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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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/*
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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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struct list_head list;
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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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} 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 *,
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struct net *, struct auth_domain *, struct module *);
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void nfs_uuid_invalidate_clients(struct list_head *list);
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void nfs_uuid_invalidate_one_client(nfs_uuid_t *nfs_uuid);
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/* localio needs to map filehandle -> struct nfsd_file */
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extern struct nfsd_file *
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nfsd_open_local_fh(struct net *, struct auth_domain *, struct rpc_clnt *,
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const struct cred *, const struct nfs_fh *,
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const fmode_t) __must_hold(rcu);
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struct nfsd_localio_operations {
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bool (*nfsd_serv_try_get)(struct net *);
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void (*nfsd_serv_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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const fmode_t);
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void (*nfsd_file_put_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 *, const fmode_t);
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static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio)
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{
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/*
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* Once reference to nfsd_serv is dropped, NFSD could be
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* unloaded, so ensure safe return from nfsd_file_put_local()
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* by always taking RCU.
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*/
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rcu_read_lock();
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nfs_to->nfsd_file_put_local(localio);
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rcu_read_unlock();
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}
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#else /* CONFIG_NFS_LOCALIO */
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static inline void nfsd_localio_ops_init(void)
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{
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}
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static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio)
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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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