linux/fs/nfsd/nfssvc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Central processing for nfsd.
 *
 * Authors:	Olaf Kirch ([email protected])
 *
 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <[email protected]>
 */

#include <linux/sched/signal.h>
#include <linux/freezer.h>
#include <linux/module.h>
#include <linux/fs_struct.h>
#include <linux/swap.h>
#include <linux/siphash.h>

#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/svc_xprt.h>
#include <linux/lockd/bind.h>
#include <linux/nfsacl.h>
#include <linux/seq_file.h>
#include <linux/inetdevice.h>
#include <net/addrconf.h>
#include <net/ipv6.h>
#include <net/net_namespace.h>
#include "nfsd.h"
#include "cache.h"
#include "vfs.h"
#include "netns.h"
#include "filecache.h"

#include "trace.h"

#define NFSDDBG_FACILITY …

atomic_t			nfsd_th_cnt = …;
extern struct svc_program	nfsd_program;
static int			nfsd(void *vrqstp);
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static int			nfsd_acl_rpcbind_set(struct net *,
						     const struct svc_program *,
						     u32, int,
						     unsigned short,
						     unsigned short);
static __be32			nfsd_acl_init_request(struct svc_rqst *,
						const struct svc_program *,
						struct svc_process_info *);
#endif
static int			nfsd_rpcbind_set(struct net *,
						 const struct svc_program *,
						 u32, int,
						 unsigned short,
						 unsigned short);
static __be32			nfsd_init_request(struct svc_rqst *,
						const struct svc_program *,
						struct svc_process_info *);

/*
 * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and some members
 * of the svc_serv struct such as ->sv_temp_socks and ->sv_permsocks.
 *
 * Finally, the nfsd_mutex also protects some of the global variables that are
 * accessed when nfsd starts and that are settable via the write_* routines in
 * nfsctl.c. In particular:
 *
 *	user_recovery_dirname
 *	user_lease_time
 *	nfsd_versions
 */
DEFINE_MUTEX(…) …;

/*
 * nfsd_drc_lock protects nfsd_drc_max_pages and nfsd_drc_pages_used.
 * nfsd_drc_max_pages limits the total amount of memory available for
 * version 4.1 DRC caches.
 * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
 */
DEFINE_SPINLOCK(…);
unsigned long	nfsd_drc_max_mem;
unsigned long	nfsd_drc_mem_used;

#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static const struct svc_version *nfsd_acl_version[] = …;

#define NFSD_ACL_MINVERS …
#define NFSD_ACL_NRVERS …

static struct svc_program	nfsd_acl_program = …;

#endif /* defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL) */

static const struct svc_version *nfsd_version[] = …;

#define NFSD_MINVERS …
#define NFSD_NRVERS …

struct svc_program		nfsd_program = …;

bool nfsd_support_version(int vers)
{ … }

static bool *
nfsd_alloc_versions(void)
{ … }

static bool *
nfsd_alloc_minorversions(void)
{ … }

void
nfsd_netns_free_versions(struct nfsd_net *nn)
{ … }

static void
nfsd_netns_init_versions(struct nfsd_net *nn)
{ … }

int nfsd_vers(struct nfsd_net *nn, int vers, enum vers_op change)
{ … }

static void
nfsd_adjust_nfsd_versions4(struct nfsd_net *nn)
{ … }

int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change)
{ … }

/*
 * Maximum number of nfsd processes
 */
#define NFSD_MAXSERVS …

int nfsd_nrthreads(struct net *net)
{ … }

static int nfsd_init_socks(struct net *net, const struct cred *cred)
{ … }

static int nfsd_users = …;

static int nfsd_startup_generic(void)
{ … }

static void nfsd_shutdown_generic(void)
{ … }

static bool nfsd_needs_lockd(struct nfsd_net *nn)
{ … }

/**
 * nfsd_copy_write_verifier - Atomically copy a write verifier
 * @verf: buffer in which to receive the verifier cookie
 * @nn: NFS net namespace
 *
 * This function provides a wait-free mechanism for copying the
 * namespace's write verifier without tearing it.
 */
void nfsd_copy_write_verifier(__be32 verf[2], struct nfsd_net *nn)
{ … }

static void nfsd_reset_write_verifier_locked(struct nfsd_net *nn)
{ … }

/**
 * nfsd_reset_write_verifier - Generate a new write verifier
 * @nn: NFS net namespace
 *
 * This function updates the ->writeverf field of @nn. This field
 * contains an opaque cookie that, according to Section 18.32.3 of
 * RFC 8881, "the client can use to determine whether a server has
 * changed instance state (e.g., server restart) between a call to
 * WRITE and a subsequent call to either WRITE or COMMIT.  This
 * cookie MUST be unchanged during a single instance of the NFSv4.1
 * server and MUST be unique between instances of the NFSv4.1
 * server."
 */
void nfsd_reset_write_verifier(struct nfsd_net *nn)
{ … }

/*
 * Crank up a set of per-namespace resources for a new NFSD instance,
 * including lockd, a duplicate reply cache, an open file cache
 * instance, and a cache of NFSv4 state objects.
 */
static int nfsd_startup_net(struct net *net, const struct cred *cred)
{ … }

static void nfsd_shutdown_net(struct net *net)
{ … }

static DEFINE_SPINLOCK(nfsd_notifier_lock);
static int nfsd_inetaddr_event(struct notifier_block *this, unsigned long event,
	void *ptr)
{ … }

static struct notifier_block nfsd_inetaddr_notifier = …;

#if IS_ENABLED(CONFIG_IPV6)
static int nfsd_inet6addr_event(struct notifier_block *this,
	unsigned long event, void *ptr)
{ … }

static struct notifier_block nfsd_inet6addr_notifier = …;
#endif

/* Only used under nfsd_mutex, so this atomic may be overkill: */
static atomic_t nfsd_notifier_refcount = …;

/**
 * nfsd_destroy_serv - tear down NFSD's svc_serv for a namespace
 * @net: network namespace the NFS service is associated with
 */
void nfsd_destroy_serv(struct net *net)
{ … }

void nfsd_reset_versions(struct nfsd_net *nn)
{ … }

/*
 * Each session guarantees a negotiated per slot memory cache for replies
 * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
 * NFSv4.1 server might want to use more memory for a DRC than a machine
 * with mutiple services.
 *
 * Impose a hard limit on the number of pages for the DRC which varies
 * according to the machines free pages. This is of course only a default.
 *
 * For now this is a #defined shift which could be under admin control
 * in the future.
 */
static void set_max_drc(void)
{ … }

static int nfsd_get_default_max_blksize(void)
{ … }

void nfsd_shutdown_threads(struct net *net)
{ … }

bool i_am_nfsd(void)
{ … }

int nfsd_create_serv(struct net *net)
{ … }

int nfsd_nrpools(struct net *net)
{ … }

int nfsd_get_nrthreads(int n, int *nthreads, struct net *net)
{ … }

/**
 * nfsd_set_nrthreads - set the number of running threads in the net's service
 * @n: number of array members in @nthreads
 * @nthreads: array of thread counts for each pool
 * @net: network namespace to operate within
 *
 * This function alters the number of running threads for the given network
 * namespace in each pool. If passed an array longer then the number of pools
 * the extra pool settings are ignored. If passed an array shorter than the
 * number of pools, the missing values are interpreted as 0's.
 *
 * Returns 0 on success or a negative errno on error.
 */
int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
{ … }

/**
 * nfsd_svc: start up or shut down the nfsd server
 * @n: number of array members in @nthreads
 * @nthreads: array of thread counts for each pool
 * @net: network namespace to operate within
 * @cred: credentials to use for xprt creation
 * @scope: server scope value (defaults to nodename)
 *
 * Adjust the number of threads in each pool and return the new
 * total number of threads in the service.
 */
int
nfsd_svc(int n, int *nthreads, struct net *net, const struct cred *cred, const char *scope)
{ … }

#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
static bool
nfsd_support_acl_version(int vers)
{ … }

static int
nfsd_acl_rpcbind_set(struct net *net, const struct svc_program *progp,
		     u32 version, int family, unsigned short proto,
		     unsigned short port)
{ … }

static __be32
nfsd_acl_init_request(struct svc_rqst *rqstp,
		      const struct svc_program *progp,
		      struct svc_process_info *ret)
{ … }
#endif

static int
nfsd_rpcbind_set(struct net *net, const struct svc_program *progp,
		 u32 version, int family, unsigned short proto,
		 unsigned short port)
{ … }

static __be32
nfsd_init_request(struct svc_rqst *rqstp,
		  const struct svc_program *progp,
		  struct svc_process_info *ret)
{ … }

/*
 * This is the NFS server kernel thread
 */
static int
nfsd(void *vrqstp)
{ … }

/**
 * nfsd_dispatch - Process an NFS or NFSACL Request
 * @rqstp: incoming request
 *
 * This RPC dispatcher integrates the NFS server's duplicate reply cache.
 *
 * Return values:
 *  %0: Processing complete; do not send a Reply
 *  %1: Processing complete; send Reply in rqstp->rq_res
 */
int nfsd_dispatch(struct svc_rqst *rqstp)
{ … }

/**
 * nfssvc_decode_voidarg - Decode void arguments
 * @rqstp: Server RPC transaction context
 * @xdr: XDR stream positioned at arguments to decode
 *
 * Return values:
 *   %false: Arguments were not valid
 *   %true: Decoding was successful
 */
bool nfssvc_decode_voidarg(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{ … }

/**
 * nfssvc_encode_voidres - Encode void results
 * @rqstp: Server RPC transaction context
 * @xdr: XDR stream into which to encode results
 *
 * Return values:
 *   %false: Local error while encoding
 *   %true: Encoding was successful
 */
bool nfssvc_encode_voidres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
{ … }

int nfsd_pool_stats_open(struct inode *inode, struct file *file)
{ … }