1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  linux/fs/nfs/super.c
4 *
5 *  Copyright (C) 1992  Rick Sladkey
6 *
7 *  nfs superblock handling functions
8 *
9 *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
10 *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
11 *
12 *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
13 *  J.S.Peatfield@damtp.cam.ac.uk
14 *
15 *  Split from inode.c by David Howells <dhowells@redhat.com>
16 *
17 * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
18 *   particular server are held in the same superblock
19 * - NFS superblocks can have several effective roots to the dentry tree
20 * - directory type roots are spliced into the tree when a path from one root reaches the root
21 *   of another (see nfs_lookup())
22 */
23
24#include <linux/module.h>
25#include <linux/init.h>
26
27#include <linux/time.h>
28#include <linux/kernel.h>
29#include <linux/mm.h>
30#include <linux/string.h>
31#include <linux/stat.h>
32#include <linux/errno.h>
33#include <linux/unistd.h>
34#include <linux/sunrpc/clnt.h>
35#include <linux/sunrpc/addr.h>
36#include <linux/sunrpc/stats.h>
37#include <linux/sunrpc/metrics.h>
38#include <linux/sunrpc/xprtsock.h>
39#include <linux/sunrpc/xprtrdma.h>
40#include <linux/nfs_fs.h>
41#include <linux/nfs_mount.h>
42#include <linux/nfs4_mount.h>
43#include <linux/lockd/bind.h>
44#include <linux/seq_file.h>
45#include <linux/mount.h>
46#include <linux/namei.h>
47#include <linux/vfs.h>
48#include <linux/inet.h>
49#include <linux/in6.h>
50#include <linux/slab.h>
51#include <net/ipv6.h>
52#include <linux/netdevice.h>
53#include <linux/nfs_xdr.h>
54#include <linux/magic.h>
55#include <linux/parser.h>
56#include <linux/nsproxy.h>
57#include <linux/rcupdate.h>
58
59#include <linux/uaccess.h>
60#include <linux/nfs_ssc.h>
61
62#include <uapi/linux/tls.h>
63
64#include "nfs4_fs.h"
65#include "callback.h"
66#include "delegation.h"
67#include "iostat.h"
68#include "internal.h"
69#include "fscache.h"
70#include "nfs4session.h"
71#include "pnfs.h"
72#include "nfs.h"
73#include "netns.h"
74#include "sysfs.h"
75
76#define NFSDBG_FACILITY		NFSDBG_VFS
77
78const struct super_operations nfs_sops = {
79	.alloc_inode	= nfs_alloc_inode,
80	.free_inode	= nfs_free_inode,
81	.write_inode	= nfs_write_inode,
82	.drop_inode	= nfs_drop_inode,
83	.statfs		= nfs_statfs,
84	.evict_inode	= nfs_evict_inode,
85	.umount_begin	= nfs_umount_begin,
86	.show_options	= nfs_show_options,
87	.show_devname	= nfs_show_devname,
88	.show_path	= nfs_show_path,
89	.show_stats	= nfs_show_stats,
90};
91EXPORT_SYMBOL_GPL(nfs_sops);
92
93#ifdef CONFIG_NFS_V4_2
94static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
95	.sco_sb_deactive = nfs_sb_deactive,
96};
97#endif
98
99#if IS_ENABLED(CONFIG_NFS_V4)
100static int __init register_nfs4_fs(void)
101{
102	return register_filesystem(&nfs4_fs_type);
103}
104
105static void unregister_nfs4_fs(void)
106{
107	unregister_filesystem(&nfs4_fs_type);
108}
109#else
110static int __init register_nfs4_fs(void)
111{
112	return 0;
113}
114
115static void unregister_nfs4_fs(void)
116{
117}
118#endif
119
120#ifdef CONFIG_NFS_V4_2
121static void nfs_ssc_register_ops(void)
122{
123	nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
124}
125
126static void nfs_ssc_unregister_ops(void)
127{
128	nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
129}
130#endif /* CONFIG_NFS_V4_2 */
131
132static struct shrinker *acl_shrinker;
133
134/*
135 * Register the NFS filesystems
136 */
137int __init register_nfs_fs(void)
138{
139	int ret;
140
141        ret = register_filesystem(&nfs_fs_type);
142	if (ret < 0)
143		goto error_0;
144
145	ret = register_nfs4_fs();
146	if (ret < 0)
147		goto error_1;
148
149	ret = nfs_register_sysctl();
150	if (ret < 0)
151		goto error_2;
152
153	acl_shrinker = shrinker_alloc(0, "nfs-acl");
154	if (!acl_shrinker) {
155		ret = -ENOMEM;
156		goto error_3;
157	}
158
159	acl_shrinker->count_objects = nfs_access_cache_count;
160	acl_shrinker->scan_objects = nfs_access_cache_scan;
161
162	shrinker_register(acl_shrinker);
163
164#ifdef CONFIG_NFS_V4_2
165	nfs_ssc_register_ops();
166#endif
167	return 0;
168error_3:
169	nfs_unregister_sysctl();
170error_2:
171	unregister_nfs4_fs();
172error_1:
173	unregister_filesystem(&nfs_fs_type);
174error_0:
175	return ret;
176}
177
178/*
179 * Unregister the NFS filesystems
180 */
181void __exit unregister_nfs_fs(void)
182{
183	shrinker_free(acl_shrinker);
184	nfs_unregister_sysctl();
185	unregister_nfs4_fs();
186#ifdef CONFIG_NFS_V4_2
187	nfs_ssc_unregister_ops();
188#endif
189	unregister_filesystem(&nfs_fs_type);
190}
191
192bool nfs_sb_active(struct super_block *sb)
193{
194	struct nfs_server *server = NFS_SB(sb);
195
196	if (!atomic_inc_not_zero(&sb->s_active))
197		return false;
198	if (atomic_inc_return(&server->active) != 1)
199		atomic_dec(&sb->s_active);
200	return true;
201}
202EXPORT_SYMBOL_GPL(nfs_sb_active);
203
204void nfs_sb_deactive(struct super_block *sb)
205{
206	struct nfs_server *server = NFS_SB(sb);
207
208	if (atomic_dec_and_test(&server->active))
209		deactivate_super(sb);
210}
211EXPORT_SYMBOL_GPL(nfs_sb_deactive);
212
213static int __nfs_list_for_each_server(struct list_head *head,
214		int (*fn)(struct nfs_server *, void *),
215		void *data)
216{
217	struct nfs_server *server, *last = NULL;
218	int ret = 0;
219
220	rcu_read_lock();
221	list_for_each_entry_rcu(server, head, client_link) {
222		if (!(server->super && nfs_sb_active(server->super)))
223			continue;
224		rcu_read_unlock();
225		if (last)
226			nfs_sb_deactive(last->super);
227		last = server;
228		ret = fn(server, data);
229		if (ret)
230			goto out;
231		rcu_read_lock();
232	}
233	rcu_read_unlock();
234out:
235	if (last)
236		nfs_sb_deactive(last->super);
237	return ret;
238}
239
240int nfs_client_for_each_server(struct nfs_client *clp,
241		int (*fn)(struct nfs_server *, void *),
242		void *data)
243{
244	return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
245}
246EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
247
248/*
249 * Deliver file system statistics to userspace
250 */
251int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
252{
253	struct nfs_server *server = NFS_SB(dentry->d_sb);
254	unsigned char blockbits;
255	unsigned long blockres;
256	struct nfs_fh *fh = NFS_FH(d_inode(dentry));
257	struct nfs_fsstat res;
258	int error = -ENOMEM;
259
260	res.fattr = nfs_alloc_fattr();
261	if (res.fattr == NULL)
262		goto out_err;
263
264	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
265	if (unlikely(error == -ESTALE)) {
266		struct dentry *pd_dentry;
267
268		pd_dentry = dget_parent(dentry);
269		nfs_zap_caches(d_inode(pd_dentry));
270		dput(pd_dentry);
271	}
272	nfs_free_fattr(res.fattr);
273	if (error < 0)
274		goto out_err;
275
276	buf->f_type = NFS_SUPER_MAGIC;
277
278	/*
279	 * Current versions of glibc do not correctly handle the
280	 * case where f_frsize != f_bsize.  Eventually we want to
281	 * report the value of wtmult in this field.
282	 */
283	buf->f_frsize = dentry->d_sb->s_blocksize;
284
285	/*
286	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
287	 * are reported in units of f_frsize.  Linux hasn't had
288	 * an f_frsize field in its statfs struct until recently,
289	 * thus historically Linux's sys_statfs reports these
290	 * fields in units of f_bsize.
291	 */
292	buf->f_bsize = dentry->d_sb->s_blocksize;
293	blockbits = dentry->d_sb->s_blocksize_bits;
294	blockres = (1 << blockbits) - 1;
295	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
296	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
297	buf->f_bavail = (res.abytes + blockres) >> blockbits;
298
299	buf->f_files = res.tfiles;
300	buf->f_ffree = res.afiles;
301
302	buf->f_namelen = server->namelen;
303
304	return 0;
305
306 out_err:
307	dprintk("%s: statfs error = %d\n", __func__, -error);
308	return error;
309}
310EXPORT_SYMBOL_GPL(nfs_statfs);
311
312/*
313 * Map the security flavour number to a name
314 */
315static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
316{
317	static const struct {
318		rpc_authflavor_t flavour;
319		const char *str;
320	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
321		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
322		{ RPC_AUTH_NULL, "null" },
323		{ RPC_AUTH_UNIX, "sys" },
324		{ RPC_AUTH_GSS_KRB5, "krb5" },
325		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
326		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
327		{ RPC_AUTH_GSS_LKEY, "lkey" },
328		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
329		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
330		{ RPC_AUTH_GSS_SPKM, "spkm" },
331		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
332		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
333		{ UINT_MAX, "unknown" }
334	};
335	int i;
336
337	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
338		if (sec_flavours[i].flavour == flavour)
339			break;
340	}
341	return sec_flavours[i].str;
342}
343
344static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
345				  int showdefaults)
346{
347	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
348	char *proto = NULL;
349
350	switch (sap->sa_family) {
351	case AF_INET:
352		switch (nfss->mountd_protocol) {
353		case IPPROTO_UDP:
354			proto = RPCBIND_NETID_UDP;
355			break;
356		case IPPROTO_TCP:
357			proto = RPCBIND_NETID_TCP;
358			break;
359		}
360		break;
361	case AF_INET6:
362		switch (nfss->mountd_protocol) {
363		case IPPROTO_UDP:
364			proto = RPCBIND_NETID_UDP6;
365			break;
366		case IPPROTO_TCP:
367			proto = RPCBIND_NETID_TCP6;
368			break;
369		}
370		break;
371	}
372	if (proto || showdefaults)
373		seq_printf(m, ",mountproto=%s", proto ?: "auto");
374}
375
376static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
377				    int showdefaults)
378{
379	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
380
381	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
382		return;
383
384	switch (sap->sa_family) {
385	case AF_INET: {
386		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
387		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
388		break;
389	}
390	case AF_INET6: {
391		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
392		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
393		break;
394	}
395	default:
396		if (showdefaults)
397			seq_puts(m, ",mountaddr=unspecified");
398	}
399
400	if (nfss->mountd_version || showdefaults)
401		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
402	if ((nfss->mountd_port &&
403		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
404		showdefaults)
405		seq_printf(m, ",mountport=%u", nfss->mountd_port);
406
407	nfs_show_mountd_netid(m, nfss, showdefaults);
408}
409
410#if IS_ENABLED(CONFIG_NFS_V4)
411static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
412				    int showdefaults)
413{
414	struct nfs_client *clp = nfss->nfs_client;
415
416	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
417}
418#else
419static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
420				    int showdefaults)
421{
422}
423#endif
424
425static void nfs_show_nfs_version(struct seq_file *m,
426		unsigned int version,
427		unsigned int minorversion)
428{
429	seq_printf(m, ",vers=%u", version);
430	if (version == 4)
431		seq_printf(m, ".%u", minorversion);
432}
433
434/*
435 * Describe the mount options in force on this server representation
436 */
437static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
438				   int showdefaults)
439{
440	static const struct proc_nfs_info {
441		int flag;
442		const char *str;
443		const char *nostr;
444	} nfs_info[] = {
445		{ NFS_MOUNT_SOFT, ",soft", "" },
446		{ NFS_MOUNT_SOFTERR, ",softerr", "" },
447		{ NFS_MOUNT_SOFTREVAL, ",softreval", "" },
448		{ NFS_MOUNT_POSIX, ",posix", "" },
449		{ NFS_MOUNT_NOCTO, ",nocto", "" },
450		{ NFS_MOUNT_NOAC, ",noac", "" },
451		{ NFS_MOUNT_NONLM, ",nolock", "" },
452		{ NFS_MOUNT_NOACL, ",noacl", "" },
453		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
454		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
455		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
456		{ 0, NULL, NULL }
457	};
458	const struct proc_nfs_info *nfs_infop;
459	struct nfs_client *clp = nfss->nfs_client;
460	u32 version = clp->rpc_ops->version;
461	int local_flock, local_fcntl;
462
463	nfs_show_nfs_version(m, version, clp->cl_minorversion);
464	seq_printf(m, ",rsize=%u", nfss->rsize);
465	seq_printf(m, ",wsize=%u", nfss->wsize);
466	if (nfss->bsize != 0)
467		seq_printf(m, ",bsize=%u", nfss->bsize);
468	seq_printf(m, ",namlen=%u", nfss->namelen);
469	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
470		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
471	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
472		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
473	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
474		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
475	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
476		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
477	if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
478			seq_puts(m, ",hard");
479	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
480		if (nfss->flags & nfs_infop->flag)
481			seq_puts(m, nfs_infop->str);
482		else
483			seq_puts(m, nfs_infop->nostr);
484	}
485	rcu_read_lock();
486	seq_printf(m, ",proto=%s",
487		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
488	rcu_read_unlock();
489	if (clp->cl_nconnect > 0)
490		seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
491	if (version == 4) {
492		if (clp->cl_max_connect > 1)
493			seq_printf(m, ",max_connect=%u", clp->cl_max_connect);
494		if (nfss->port != NFS_PORT)
495			seq_printf(m, ",port=%u", nfss->port);
496	} else
497		if (nfss->port)
498			seq_printf(m, ",port=%u", nfss->port);
499
500	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
501	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
502	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
503	switch (clp->cl_xprtsec.policy) {
504	case RPC_XPRTSEC_TLS_ANON:
505		seq_puts(m, ",xprtsec=tls");
506		break;
507	case RPC_XPRTSEC_TLS_X509:
508		seq_puts(m, ",xprtsec=mtls");
509		break;
510	default:
511		break;
512	}
513
514	if (version != 4)
515		nfs_show_mountd_options(m, nfss, showdefaults);
516	else
517		nfs_show_nfsv4_options(m, nfss, showdefaults);
518
519	if (nfss->options & NFS_OPTION_FSCACHE) {
520#ifdef CONFIG_NFS_FSCACHE
521		if (nfss->fscache_uniq)
522			seq_printf(m, ",fsc=%s", nfss->fscache_uniq);
523		else
524			seq_puts(m, ",fsc");
525#else
526		seq_puts(m, ",fsc");
527#endif
528	}
529
530	if (nfss->options & NFS_OPTION_MIGRATION)
531		seq_puts(m, ",migration");
532
533	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
534		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
535			seq_puts(m, ",lookupcache=none");
536		else
537			seq_puts(m, ",lookupcache=pos");
538	}
539
540	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
541	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
542
543	if (!local_flock && !local_fcntl)
544		seq_puts(m, ",local_lock=none");
545	else if (local_flock && local_fcntl)
546		seq_puts(m, ",local_lock=all");
547	else if (local_flock)
548		seq_puts(m, ",local_lock=flock");
549	else
550		seq_puts(m, ",local_lock=posix");
551
552	if (nfss->flags & NFS_MOUNT_WRITE_EAGER) {
553		if (nfss->flags & NFS_MOUNT_WRITE_WAIT)
554			seq_puts(m, ",write=wait");
555		else
556			seq_puts(m, ",write=eager");
557	}
558}
559
560/*
561 * Describe the mount options on this VFS mountpoint
562 */
563int nfs_show_options(struct seq_file *m, struct dentry *root)
564{
565	struct nfs_server *nfss = NFS_SB(root->d_sb);
566
567	nfs_show_mount_options(m, nfss, 0);
568
569	rcu_read_lock();
570	seq_printf(m, ",addr=%s",
571			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
572							RPC_DISPLAY_ADDR));
573	rcu_read_unlock();
574
575	return 0;
576}
577EXPORT_SYMBOL_GPL(nfs_show_options);
578
579#if IS_ENABLED(CONFIG_NFS_V4)
580static void show_lease(struct seq_file *m, struct nfs_server *server)
581{
582	struct nfs_client *clp = server->nfs_client;
583	unsigned long expire;
584
585	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
586	expire = clp->cl_last_renewal + clp->cl_lease_time;
587	seq_printf(m, ",lease_expired=%ld",
588		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
589}
590#ifdef CONFIG_NFS_V4_1
591static void show_sessions(struct seq_file *m, struct nfs_server *server)
592{
593	if (nfs4_has_session(server->nfs_client))
594		seq_puts(m, ",sessions");
595}
596#else
597static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
598#endif
599#endif
600
601#ifdef CONFIG_NFS_V4_1
602static void show_pnfs(struct seq_file *m, struct nfs_server *server)
603{
604	seq_printf(m, ",pnfs=");
605	if (server->pnfs_curr_ld)
606		seq_printf(m, "%s", server->pnfs_curr_ld->name);
607	else
608		seq_printf(m, "not configured");
609}
610
611static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
612{
613	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
614		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
615		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
616			   "date='%llu,%u'",
617			   impl_id->name, impl_id->domain,
618			   impl_id->date.seconds, impl_id->date.nseconds);
619	}
620}
621#else
622#if IS_ENABLED(CONFIG_NFS_V4)
623static void show_pnfs(struct seq_file *m, struct nfs_server *server)
624{
625}
626#endif
627static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
628{
629}
630#endif
631
632int nfs_show_devname(struct seq_file *m, struct dentry *root)
633{
634	char *page = (char *) __get_free_page(GFP_KERNEL);
635	char *devname, *dummy;
636	int err = 0;
637	if (!page)
638		return -ENOMEM;
639	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
640	if (IS_ERR(devname))
641		err = PTR_ERR(devname);
642	else
643		seq_escape(m, devname, " \t\n\\");
644	free_page((unsigned long)page);
645	return err;
646}
647EXPORT_SYMBOL_GPL(nfs_show_devname);
648
649int nfs_show_path(struct seq_file *m, struct dentry *dentry)
650{
651	seq_puts(m, "/");
652	return 0;
653}
654EXPORT_SYMBOL_GPL(nfs_show_path);
655
656/*
657 * Present statistical information for this VFS mountpoint
658 */
659int nfs_show_stats(struct seq_file *m, struct dentry *root)
660{
661	int i, cpu;
662	struct nfs_server *nfss = NFS_SB(root->d_sb);
663	struct rpc_auth *auth = nfss->client->cl_auth;
664	struct nfs_iostats totals = { };
665
666	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
667
668	/*
669	 * Display all mount option settings
670	 */
671	seq_puts(m, "\n\topts:\t");
672	seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
673	seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
674	seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
675	seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
676	nfs_show_mount_options(m, nfss, 1);
677
678	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
679
680	show_implementation_id(m, nfss);
681
682	seq_puts(m, "\n\tcaps:\t");
683	seq_printf(m, "caps=0x%x", nfss->caps);
684	seq_printf(m, ",wtmult=%u", nfss->wtmult);
685	seq_printf(m, ",dtsize=%u", nfss->dtsize);
686	seq_printf(m, ",bsize=%u", nfss->bsize);
687	seq_printf(m, ",namlen=%u", nfss->namelen);
688
689#if IS_ENABLED(CONFIG_NFS_V4)
690	if (nfss->nfs_client->rpc_ops->version == 4) {
691		seq_puts(m, "\n\tnfsv4:\t");
692		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
693		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
694		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
695		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
696		show_sessions(m, nfss);
697		show_pnfs(m, nfss);
698		show_lease(m, nfss);
699	}
700#endif
701
702	/*
703	 * Display security flavor in effect for this mount
704	 */
705	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
706	if (auth->au_flavor)
707		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
708
709	/*
710	 * Display superblock I/O counters
711	 */
712	for_each_possible_cpu(cpu) {
713		struct nfs_iostats *stats;
714
715		preempt_disable();
716		stats = per_cpu_ptr(nfss->io_stats, cpu);
717
718		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
719			totals.events[i] += stats->events[i];
720		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
721			totals.bytes[i] += stats->bytes[i];
722
723		preempt_enable();
724	}
725
726	seq_puts(m, "\n\tevents:\t");
727	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
728		seq_printf(m, "%lu ", totals.events[i]);
729	seq_puts(m, "\n\tbytes:\t");
730	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
731		seq_printf(m, "%Lu ", totals.bytes[i]);
732	seq_putc(m, '\n');
733
734	rpc_clnt_show_stats(m, nfss->client);
735
736	return 0;
737}
738EXPORT_SYMBOL_GPL(nfs_show_stats);
739
740/*
741 * Begin unmount by attempting to remove all automounted mountpoints we added
742 * in response to xdev traversals and referrals
743 */
744void nfs_umount_begin(struct super_block *sb)
745{
746	struct nfs_server *server;
747	struct rpc_clnt *rpc;
748
749	server = NFS_SB(sb);
750	/* -EIO all pending I/O */
751	rpc = server->client_acl;
752	if (!IS_ERR(rpc))
753		rpc_killall_tasks(rpc);
754	rpc = server->client;
755	if (!IS_ERR(rpc))
756		rpc_killall_tasks(rpc);
757}
758EXPORT_SYMBOL_GPL(nfs_umount_begin);
759
760/*
761 * Return true if 'match' is in auth_info or auth_info is empty.
762 * Return false otherwise.
763 */
764bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
765			 rpc_authflavor_t match)
766{
767	int i;
768
769	if (!auth_info->flavor_len)
770		return true;
771
772	for (i = 0; i < auth_info->flavor_len; i++) {
773		if (auth_info->flavors[i] == match)
774			return true;
775	}
776	return false;
777}
778EXPORT_SYMBOL_GPL(nfs_auth_info_match);
779
780/*
781 * Ensure that a specified authtype in ctx->auth_info is supported by
782 * the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
783 * -EACCES if not.
784 */
785static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
786				  rpc_authflavor_t *server_authlist,
787				  unsigned int count)
788{
789	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
790	bool found_auth_null = false;
791	unsigned int i;
792
793	/*
794	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
795	 * must be in the list returned by the server.
796	 *
797	 * AUTH_NULL has a special meaning when it's in the server list - it
798	 * means that the server will ignore the rpc creds, so any flavor
799	 * can be used but still use the sec= that was specified.
800	 *
801	 * Note also that the MNT procedure in MNTv1 does not return a list
802	 * of supported security flavors. In this case, nfs_mount() fabricates
803	 * a security flavor list containing just AUTH_NULL.
804	 */
805	for (i = 0; i < count; i++) {
806		flavor = server_authlist[i];
807
808		if (nfs_auth_info_match(&ctx->auth_info, flavor))
809			goto out;
810
811		if (flavor == RPC_AUTH_NULL)
812			found_auth_null = true;
813	}
814
815	if (found_auth_null) {
816		flavor = ctx->auth_info.flavors[0];
817		goto out;
818	}
819
820	dfprintk(MOUNT,
821		 "NFS: specified auth flavors not supported by server\n");
822	return -EACCES;
823
824out:
825	ctx->selected_flavor = flavor;
826	dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
827	return 0;
828}
829
830/*
831 * Use the remote server's MOUNT service to request the NFS file handle
832 * corresponding to the provided path.
833 */
834static int nfs_request_mount(struct fs_context *fc,
835			     struct nfs_fh *root_fh,
836			     rpc_authflavor_t *server_authlist,
837			     unsigned int *server_authlist_len)
838{
839	struct nfs_fs_context *ctx = nfs_fc2context(fc);
840	struct nfs_mount_request request = {
841		.sap		= &ctx->mount_server._address,
842		.dirpath	= ctx->nfs_server.export_path,
843		.protocol	= ctx->mount_server.protocol,
844		.fh		= root_fh,
845		.noresvport	= ctx->flags & NFS_MOUNT_NORESVPORT,
846		.auth_flav_len	= server_authlist_len,
847		.auth_flavs	= server_authlist,
848		.net		= fc->net_ns,
849	};
850	int status;
851
852	if (ctx->mount_server.version == 0) {
853		switch (ctx->version) {
854			default:
855				ctx->mount_server.version = NFS_MNT3_VERSION;
856				break;
857			case 2:
858				ctx->mount_server.version = NFS_MNT_VERSION;
859		}
860	}
861	request.version = ctx->mount_server.version;
862
863	if (ctx->mount_server.hostname)
864		request.hostname = ctx->mount_server.hostname;
865	else
866		request.hostname = ctx->nfs_server.hostname;
867
868	/*
869	 * Construct the mount server's address.
870	 */
871	if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
872		memcpy(request.sap, &ctx->nfs_server._address,
873		       ctx->nfs_server.addrlen);
874		ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
875	}
876	request.salen = ctx->mount_server.addrlen;
877	nfs_set_port(request.sap, &ctx->mount_server.port, 0);
878
879	/*
880	 * Now ask the mount server to map our export path
881	 * to a file handle.
882	 */
883	status = nfs_mount(&request, ctx->timeo, ctx->retrans);
884	if (status != 0) {
885		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
886				request.hostname, status);
887		return status;
888	}
889
890	return 0;
891}
892
893static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
894{
895	struct nfs_fs_context *ctx = nfs_fc2context(fc);
896	int status;
897	unsigned int i;
898	bool tried_auth_unix = false;
899	bool auth_null_in_list = false;
900	struct nfs_server *server = ERR_PTR(-EACCES);
901	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
902	unsigned int authlist_len = ARRAY_SIZE(authlist);
903
904	/* make sure 'nolock'/'lock' override the 'local_lock' mount option */
905	if (ctx->lock_status) {
906		if (ctx->lock_status == NFS_LOCK_NOLOCK) {
907			ctx->flags |= NFS_MOUNT_NONLM;
908			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
909		} else {
910			ctx->flags &= ~NFS_MOUNT_NONLM;
911			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
912		}
913	}
914	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
915	if (status)
916		return ERR_PTR(status);
917
918	/*
919	 * Was a sec= authflavor specified in the options? First, verify
920	 * whether the server supports it, and then just try to use it if so.
921	 */
922	if (ctx->auth_info.flavor_len > 0) {
923		status = nfs_verify_authflavors(ctx, authlist, authlist_len);
924		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
925			 ctx->selected_flavor);
926		if (status)
927			return ERR_PTR(status);
928		return ctx->nfs_mod->rpc_ops->create_server(fc);
929	}
930
931	/*
932	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
933	 * SHOULD prefer the flavor listed first. However, some servers list
934	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
935	 */
936	for (i = 0; i < authlist_len; ++i) {
937		rpc_authflavor_t flavor;
938		struct rpcsec_gss_info info;
939
940		flavor = authlist[i];
941		switch (flavor) {
942		case RPC_AUTH_UNIX:
943			tried_auth_unix = true;
944			break;
945		case RPC_AUTH_NULL:
946			auth_null_in_list = true;
947			continue;
948		default:
949			if (rpcauth_get_gssinfo(flavor, &info) != 0)
950				continue;
951			break;
952		}
953		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
954		ctx->selected_flavor = flavor;
955		server = ctx->nfs_mod->rpc_ops->create_server(fc);
956		if (!IS_ERR(server))
957			return server;
958	}
959
960	/*
961	 * Nothing we tried so far worked. At this point, give up if we've
962	 * already tried AUTH_UNIX or if the server's list doesn't contain
963	 * AUTH_NULL
964	 */
965	if (tried_auth_unix || !auth_null_in_list)
966		return server;
967
968	/* Last chance! Try AUTH_UNIX */
969	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
970	ctx->selected_flavor = RPC_AUTH_UNIX;
971	return ctx->nfs_mod->rpc_ops->create_server(fc);
972}
973
974int nfs_try_get_tree(struct fs_context *fc)
975{
976	struct nfs_fs_context *ctx = nfs_fc2context(fc);
977
978	if (ctx->need_mount)
979		ctx->server = nfs_try_mount_request(fc);
980	else
981		ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
982
983	return nfs_get_tree_common(fc);
984}
985EXPORT_SYMBOL_GPL(nfs_try_get_tree);
986
987
988#define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
989		| NFS_MOUNT_SECURE \
990		| NFS_MOUNT_TCP \
991		| NFS_MOUNT_VER3 \
992		| NFS_MOUNT_KERBEROS \
993		| NFS_MOUNT_NONLM \
994		| NFS_MOUNT_BROKEN_SUID \
995		| NFS_MOUNT_STRICTLOCK \
996		| NFS_MOUNT_LEGACY_INTERFACE)
997
998#define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
999		~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
1000
1001static int
1002nfs_compare_remount_data(struct nfs_server *nfss,
1003			 struct nfs_fs_context *ctx)
1004{
1005	if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
1006	    ctx->rsize != nfss->rsize ||
1007	    ctx->wsize != nfss->wsize ||
1008	    ctx->version != nfss->nfs_client->rpc_ops->version ||
1009	    ctx->minorversion != nfss->nfs_client->cl_minorversion ||
1010	    ctx->retrans != nfss->client->cl_timeout->to_retries ||
1011	    !nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
1012	    ctx->acregmin != nfss->acregmin / HZ ||
1013	    ctx->acregmax != nfss->acregmax / HZ ||
1014	    ctx->acdirmin != nfss->acdirmin / HZ ||
1015	    ctx->acdirmax != nfss->acdirmax / HZ ||
1016	    ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1017	    (ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
1018	    ctx->nfs_server.port != nfss->port ||
1019	    ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1020	    !rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
1021			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
1022		return -EINVAL;
1023
1024	return 0;
1025}
1026
1027int nfs_reconfigure(struct fs_context *fc)
1028{
1029	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1030	struct super_block *sb = fc->root->d_sb;
1031	struct nfs_server *nfss = sb->s_fs_info;
1032	int ret;
1033
1034	sync_filesystem(sb);
1035
1036	/*
1037	 * Userspace mount programs that send binary options generally send
1038	 * them populated with default values. We have no way to know which
1039	 * ones were explicitly specified. Fall back to legacy behavior and
1040	 * just return success.
1041	 */
1042	if (ctx->skip_reconfig_option_check)
1043		return 0;
1044
1045	/*
1046	 * noac is a special case. It implies -o sync, but that's not
1047	 * necessarily reflected in the mtab options. reconfigure_super
1048	 * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
1049	 * remount options, so we have to explicitly reset it.
1050	 */
1051	if (ctx->flags & NFS_MOUNT_NOAC) {
1052		fc->sb_flags |= SB_SYNCHRONOUS;
1053		fc->sb_flags_mask |= SB_SYNCHRONOUS;
1054	}
1055
1056	/* compare new mount options with old ones */
1057	ret = nfs_compare_remount_data(nfss, ctx);
1058	if (ret)
1059		return ret;
1060
1061	return nfs_probe_server(nfss, NFS_FH(d_inode(fc->root)));
1062}
1063EXPORT_SYMBOL_GPL(nfs_reconfigure);
1064
1065/*
1066 * Finish setting up an NFS superblock
1067 */
1068static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
1069{
1070	struct nfs_server *server = NFS_SB(sb);
1071
1072	sb->s_blocksize_bits = 0;
1073	sb->s_blocksize = 0;
1074	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
1075	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
1076	if (ctx->bsize)
1077		sb->s_blocksize = nfs_block_size(ctx->bsize, &sb->s_blocksize_bits);
1078
1079	switch (server->nfs_client->rpc_ops->version) {
1080	case 2:
1081		sb->s_time_gran = 1000;
1082		sb->s_time_min = 0;
1083		sb->s_time_max = U32_MAX;
1084		break;
1085	case 3:
1086		/*
1087		 * The VFS shouldn't apply the umask to mode bits.
1088		 * We will do so ourselves when necessary.
1089		 */
1090		sb->s_flags |= SB_POSIXACL;
1091		sb->s_time_gran = 1;
1092		sb->s_time_min = 0;
1093		sb->s_time_max = U32_MAX;
1094		sb->s_export_op = &nfs_export_ops;
1095		break;
1096	case 4:
1097		sb->s_iflags |= SB_I_NOUMASK;
1098		sb->s_time_gran = 1;
1099		sb->s_time_min = S64_MIN;
1100		sb->s_time_max = S64_MAX;
1101		if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
1102			sb->s_export_op = &nfs_export_ops;
1103		break;
1104	}
1105
1106	sb->s_magic = NFS_SUPER_MAGIC;
1107
1108	/* We probably want something more informative here */
1109	snprintf(sb->s_id, sizeof(sb->s_id),
1110		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1111
1112	if (sb->s_blocksize == 0)
1113		sb->s_blocksize = nfs_block_bits(server->wsize,
1114						 &sb->s_blocksize_bits);
1115
1116	nfs_super_set_maxbytes(sb, server->maxfilesize);
1117	nfs_sysfs_move_server_to_sb(sb);
1118	server->has_sec_mnt_opts = ctx->has_sec_mnt_opts;
1119}
1120
1121static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b,
1122				     const struct fs_context *fc)
1123{
1124	const struct nfs_server *a = s->s_fs_info;
1125	const struct rpc_clnt *clnt_a = a->client;
1126	const struct rpc_clnt *clnt_b = b->client;
1127
1128	if ((s->s_flags & NFS_SB_MASK) != (fc->sb_flags & NFS_SB_MASK))
1129		goto Ebusy;
1130	if (a->nfs_client != b->nfs_client)
1131		goto Ebusy;
1132	if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
1133		goto Ebusy;
1134	if (a->wsize != b->wsize)
1135		goto Ebusy;
1136	if (a->rsize != b->rsize)
1137		goto Ebusy;
1138	if (a->acregmin != b->acregmin)
1139		goto Ebusy;
1140	if (a->acregmax != b->acregmax)
1141		goto Ebusy;
1142	if (a->acdirmin != b->acdirmin)
1143		goto Ebusy;
1144	if (a->acdirmax != b->acdirmax)
1145		goto Ebusy;
1146	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1147		goto Ebusy;
1148	return 1;
1149Ebusy:
1150	return 0;
1151}
1152
1153static int nfs_set_super(struct super_block *s, struct fs_context *fc)
1154{
1155	struct nfs_server *server = fc->s_fs_info;
1156	int ret;
1157
1158	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
1159	ret = set_anon_super(s, server);
1160	if (ret == 0)
1161		server->s_dev = s->s_dev;
1162	return ret;
1163}
1164
1165static int nfs_compare_super_address(struct nfs_server *server1,
1166				     struct nfs_server *server2)
1167{
1168	struct sockaddr *sap1, *sap2;
1169	struct rpc_xprt *xprt1 = server1->client->cl_xprt;
1170	struct rpc_xprt *xprt2 = server2->client->cl_xprt;
1171
1172	if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
1173		return 0;
1174
1175	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1176	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1177
1178	if (sap1->sa_family != sap2->sa_family)
1179		return 0;
1180
1181	switch (sap1->sa_family) {
1182	case AF_INET: {
1183		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1184		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1185		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1186			return 0;
1187		if (sin1->sin_port != sin2->sin_port)
1188			return 0;
1189		break;
1190	}
1191	case AF_INET6: {
1192		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1193		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1194		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1195			return 0;
1196		if (sin1->sin6_port != sin2->sin6_port)
1197			return 0;
1198		break;
1199	}
1200	default:
1201		return 0;
1202	}
1203
1204	return 1;
1205}
1206
1207static int nfs_compare_userns(const struct nfs_server *old,
1208		const struct nfs_server *new)
1209{
1210	const struct user_namespace *oldns = &init_user_ns;
1211	const struct user_namespace *newns = &init_user_ns;
1212
1213	if (old->client && old->client->cl_cred)
1214		oldns = old->client->cl_cred->user_ns;
1215	if (new->client && new->client->cl_cred)
1216		newns = new->client->cl_cred->user_ns;
1217	if (oldns != newns)
1218		return 0;
1219	return 1;
1220}
1221
1222static int nfs_compare_super(struct super_block *sb, struct fs_context *fc)
1223{
1224	struct nfs_server *server = fc->s_fs_info, *old = NFS_SB(sb);
1225
1226	if (!nfs_compare_super_address(old, server))
1227		return 0;
1228	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1229	if (old->flags & NFS_MOUNT_UNSHARED)
1230		return 0;
1231	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1232		return 0;
1233	if (!nfs_compare_userns(old, server))
1234		return 0;
1235	if ((old->has_sec_mnt_opts || fc->security) &&
1236			security_sb_mnt_opts_compat(sb, fc->security))
1237		return 0;
1238	return nfs_compare_mount_options(sb, server, fc);
1239}
1240
1241#ifdef CONFIG_NFS_FSCACHE
1242static int nfs_get_cache_cookie(struct super_block *sb,
1243				struct nfs_fs_context *ctx)
1244{
1245	struct nfs_server *nfss = NFS_SB(sb);
1246	char *uniq = NULL;
1247	int ulen = 0;
1248
1249	nfss->fscache = NULL;
1250
1251	if (!ctx)
1252		return 0;
1253
1254	if (ctx->clone_data.sb) {
1255		struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
1256		if (!(mnt_s->options & NFS_OPTION_FSCACHE))
1257			return 0;
1258		if (mnt_s->fscache_uniq) {
1259			uniq = mnt_s->fscache_uniq;
1260			ulen = strlen(uniq);
1261		}
1262	} else {
1263		if (!(ctx->options & NFS_OPTION_FSCACHE))
1264			return 0;
1265		if (ctx->fscache_uniq) {
1266			uniq = ctx->fscache_uniq;
1267			ulen = strlen(ctx->fscache_uniq);
1268		}
1269	}
1270
1271	return nfs_fscache_get_super_cookie(sb, uniq, ulen);
1272}
1273#else
1274static int nfs_get_cache_cookie(struct super_block *sb,
1275				struct nfs_fs_context *ctx)
1276{
1277	return 0;
1278}
1279#endif
1280
1281int nfs_get_tree_common(struct fs_context *fc)
1282{
1283	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1284	struct super_block *s;
1285	int (*compare_super)(struct super_block *, struct fs_context *) = nfs_compare_super;
1286	struct nfs_server *server = ctx->server;
1287	int error;
1288
1289	ctx->server = NULL;
1290	if (IS_ERR(server))
1291		return PTR_ERR(server);
1292
1293	if (server->flags & NFS_MOUNT_UNSHARED)
1294		compare_super = NULL;
1295
1296	/* -o noac implies -o sync */
1297	if (server->flags & NFS_MOUNT_NOAC)
1298		fc->sb_flags |= SB_SYNCHRONOUS;
1299
1300	if (ctx->clone_data.sb)
1301		if (ctx->clone_data.sb->s_flags & SB_SYNCHRONOUS)
1302			fc->sb_flags |= SB_SYNCHRONOUS;
1303
1304	/* Get a superblock - note that we may end up sharing one that already exists */
1305	fc->s_fs_info = server;
1306	s = sget_fc(fc, compare_super, nfs_set_super);
1307	fc->s_fs_info = NULL;
1308	if (IS_ERR(s)) {
1309		error = PTR_ERR(s);
1310		nfs_errorf(fc, "NFS: Couldn't get superblock");
1311		goto out_err_nosb;
1312	}
1313
1314	if (s->s_fs_info != server) {
1315		nfs_free_server(server);
1316		server = NULL;
1317	} else {
1318		error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
1319					     MINOR(server->s_dev));
1320		if (error)
1321			goto error_splat_super;
1322		s->s_bdi->io_pages = server->rpages;
1323		server->super = s;
1324	}
1325
1326	if (!s->s_root) {
1327		unsigned bsize = ctx->clone_data.inherited_bsize;
1328		/* initial superblock/root creation */
1329		nfs_fill_super(s, ctx);
1330		if (bsize) {
1331			s->s_blocksize_bits = bsize;
1332			s->s_blocksize = 1U << bsize;
1333		}
1334		error = nfs_get_cache_cookie(s, ctx);
1335		if (error < 0)
1336			goto error_splat_super;
1337	}
1338
1339	error = nfs_get_root(s, fc);
1340	if (error < 0) {
1341		nfs_errorf(fc, "NFS: Couldn't get root dentry");
1342		goto error_splat_super;
1343	}
1344
1345	s->s_flags |= SB_ACTIVE;
1346	error = 0;
1347
1348out:
1349	return error;
1350
1351out_err_nosb:
1352	nfs_free_server(server);
1353	goto out;
1354error_splat_super:
1355	deactivate_locked_super(s);
1356	goto out;
1357}
1358
1359/*
1360 * Destroy an NFS superblock
1361 */
1362void nfs_kill_super(struct super_block *s)
1363{
1364	struct nfs_server *server = NFS_SB(s);
1365
1366	nfs_sysfs_move_sb_to_server(server);
1367	kill_anon_super(s);
1368
1369	nfs_fscache_release_super_cookie(s);
1370
1371	nfs_free_server(server);
1372}
1373EXPORT_SYMBOL_GPL(nfs_kill_super);
1374
1375#if IS_ENABLED(CONFIG_NFS_V4)
1376
1377/*
1378 * NFS v4 module parameters need to stay in the
1379 * NFS client for backwards compatibility
1380 */
1381unsigned int nfs_callback_set_tcpport;
1382unsigned short nfs_callback_nr_threads;
1383/* Default cache timeout is 10 minutes */
1384unsigned int nfs_idmap_cache_timeout = 600;
1385/* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
1386bool nfs4_disable_idmapping = true;
1387unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
1388unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
1389unsigned short send_implementation_id = 1;
1390char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
1391bool recover_lost_locks = false;
1392short nfs_delay_retrans = -1;
1393
1394EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
1395EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
1396EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
1397EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
1398EXPORT_SYMBOL_GPL(max_session_slots);
1399EXPORT_SYMBOL_GPL(max_session_cb_slots);
1400EXPORT_SYMBOL_GPL(send_implementation_id);
1401EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
1402EXPORT_SYMBOL_GPL(recover_lost_locks);
1403EXPORT_SYMBOL_GPL(nfs_delay_retrans);
1404
1405#define NFS_CALLBACK_MAXPORTNR (65535U)
1406
1407static int param_set_portnr(const char *val, const struct kernel_param *kp)
1408{
1409	unsigned long num;
1410	int ret;
1411
1412	if (!val)
1413		return -EINVAL;
1414	ret = kstrtoul(val, 0, &num);
1415	if (ret || num > NFS_CALLBACK_MAXPORTNR)
1416		return -EINVAL;
1417	*((unsigned int *)kp->arg) = num;
1418	return 0;
1419}
1420static const struct kernel_param_ops param_ops_portnr = {
1421	.set = param_set_portnr,
1422	.get = param_get_uint,
1423};
1424#define param_check_portnr(name, p) __param_check(name, p, unsigned int)
1425
1426module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1427module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
1428MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
1429		"assigned to the NFSv4 callback channels.");
1430module_param(nfs_idmap_cache_timeout, int, 0644);
1431module_param(nfs4_disable_idmapping, bool, 0644);
1432module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
1433			NFS4_CLIENT_ID_UNIQ_LEN, 0600);
1434MODULE_PARM_DESC(nfs4_disable_idmapping,
1435		"Turn off NFSv4 idmapping when using 'sec=sys'");
1436module_param(max_session_slots, ushort, 0644);
1437MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
1438		"requests the client will negotiate");
1439module_param(max_session_cb_slots, ushort, 0644);
1440MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
1441		"callbacks the client will process for a given server");
1442module_param(send_implementation_id, ushort, 0644);
1443MODULE_PARM_DESC(send_implementation_id,
1444		"Send implementation ID with NFSv4.1 exchange_id");
1445MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
1446
1447module_param(recover_lost_locks, bool, 0644);
1448MODULE_PARM_DESC(recover_lost_locks,
1449		 "If the server reports that a lock might be lost, "
1450		 "try to recover it risking data corruption.");
1451
1452module_param_named(delay_retrans, nfs_delay_retrans, short, 0644);
1453MODULE_PARM_DESC(delay_retrans,
1454		 "Unless negative, specifies the number of times the NFSv4 "
1455		 "client retries a request before returning an EAGAIN error, "
1456		 "after a reply of NFS4ERR_DELAY from the server.");
1457#endif /* CONFIG_NFS_V4 */
1458