xref: /linux/fs/nfs/super.c (revision 0c8a32eed1625a65798286fb73fea8710a908545)
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 "nfs4_fs.h"
63 #include "callback.h"
64 #include "delegation.h"
65 #include "iostat.h"
66 #include "internal.h"
67 #include "fscache.h"
68 #include "nfs4session.h"
69 #include "pnfs.h"
70 #include "nfs.h"
71 
72 #define NFSDBG_FACILITY		NFSDBG_VFS
73 
74 const struct super_operations nfs_sops = {
75 	.alloc_inode	= nfs_alloc_inode,
76 	.free_inode	= nfs_free_inode,
77 	.write_inode	= nfs_write_inode,
78 	.drop_inode	= nfs_drop_inode,
79 	.statfs		= nfs_statfs,
80 	.evict_inode	= nfs_evict_inode,
81 	.umount_begin	= nfs_umount_begin,
82 	.show_options	= nfs_show_options,
83 	.show_devname	= nfs_show_devname,
84 	.show_path	= nfs_show_path,
85 	.show_stats	= nfs_show_stats,
86 };
87 EXPORT_SYMBOL_GPL(nfs_sops);
88 
89 static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
90 	.sco_sb_deactive = nfs_sb_deactive,
91 };
92 
93 #if IS_ENABLED(CONFIG_NFS_V4)
94 static int __init register_nfs4_fs(void)
95 {
96 	return register_filesystem(&nfs4_fs_type);
97 }
98 
99 static void unregister_nfs4_fs(void)
100 {
101 	unregister_filesystem(&nfs4_fs_type);
102 }
103 #else
104 static int __init register_nfs4_fs(void)
105 {
106 	return 0;
107 }
108 
109 static void unregister_nfs4_fs(void)
110 {
111 }
112 #endif
113 
114 static void nfs_ssc_register_ops(void)
115 {
116 	nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
117 }
118 
119 static void nfs_ssc_unregister_ops(void)
120 {
121 	nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
122 }
123 
124 static struct shrinker acl_shrinker = {
125 	.count_objects	= nfs_access_cache_count,
126 	.scan_objects	= nfs_access_cache_scan,
127 	.seeks		= DEFAULT_SEEKS,
128 };
129 
130 /*
131  * Register the NFS filesystems
132  */
133 int __init register_nfs_fs(void)
134 {
135 	int ret;
136 
137         ret = register_filesystem(&nfs_fs_type);
138 	if (ret < 0)
139 		goto error_0;
140 
141 	ret = register_nfs4_fs();
142 	if (ret < 0)
143 		goto error_1;
144 
145 	ret = nfs_register_sysctl();
146 	if (ret < 0)
147 		goto error_2;
148 	ret = register_shrinker(&acl_shrinker);
149 	if (ret < 0)
150 		goto error_3;
151 	nfs_ssc_register_ops();
152 	return 0;
153 error_3:
154 	nfs_unregister_sysctl();
155 error_2:
156 	unregister_nfs4_fs();
157 error_1:
158 	unregister_filesystem(&nfs_fs_type);
159 error_0:
160 	return ret;
161 }
162 
163 /*
164  * Unregister the NFS filesystems
165  */
166 void __exit unregister_nfs_fs(void)
167 {
168 	unregister_shrinker(&acl_shrinker);
169 	nfs_unregister_sysctl();
170 	unregister_nfs4_fs();
171 	nfs_ssc_unregister_ops();
172 	unregister_filesystem(&nfs_fs_type);
173 }
174 
175 bool nfs_sb_active(struct super_block *sb)
176 {
177 	struct nfs_server *server = NFS_SB(sb);
178 
179 	if (!atomic_inc_not_zero(&sb->s_active))
180 		return false;
181 	if (atomic_inc_return(&server->active) != 1)
182 		atomic_dec(&sb->s_active);
183 	return true;
184 }
185 EXPORT_SYMBOL_GPL(nfs_sb_active);
186 
187 void nfs_sb_deactive(struct super_block *sb)
188 {
189 	struct nfs_server *server = NFS_SB(sb);
190 
191 	if (atomic_dec_and_test(&server->active))
192 		deactivate_super(sb);
193 }
194 EXPORT_SYMBOL_GPL(nfs_sb_deactive);
195 
196 static int __nfs_list_for_each_server(struct list_head *head,
197 		int (*fn)(struct nfs_server *, void *),
198 		void *data)
199 {
200 	struct nfs_server *server, *last = NULL;
201 	int ret = 0;
202 
203 	rcu_read_lock();
204 	list_for_each_entry_rcu(server, head, client_link) {
205 		if (!(server->super && nfs_sb_active(server->super)))
206 			continue;
207 		rcu_read_unlock();
208 		if (last)
209 			nfs_sb_deactive(last->super);
210 		last = server;
211 		ret = fn(server, data);
212 		if (ret)
213 			goto out;
214 		rcu_read_lock();
215 	}
216 	rcu_read_unlock();
217 out:
218 	if (last)
219 		nfs_sb_deactive(last->super);
220 	return ret;
221 }
222 
223 int nfs_client_for_each_server(struct nfs_client *clp,
224 		int (*fn)(struct nfs_server *, void *),
225 		void *data)
226 {
227 	return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
228 }
229 EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
230 
231 /*
232  * Deliver file system statistics to userspace
233  */
234 int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
235 {
236 	struct nfs_server *server = NFS_SB(dentry->d_sb);
237 	unsigned char blockbits;
238 	unsigned long blockres;
239 	struct nfs_fh *fh = NFS_FH(d_inode(dentry));
240 	struct nfs_fsstat res;
241 	int error = -ENOMEM;
242 
243 	res.fattr = nfs_alloc_fattr();
244 	if (res.fattr == NULL)
245 		goto out_err;
246 
247 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
248 	if (unlikely(error == -ESTALE)) {
249 		struct dentry *pd_dentry;
250 
251 		pd_dentry = dget_parent(dentry);
252 		nfs_zap_caches(d_inode(pd_dentry));
253 		dput(pd_dentry);
254 	}
255 	nfs_free_fattr(res.fattr);
256 	if (error < 0)
257 		goto out_err;
258 
259 	buf->f_type = NFS_SUPER_MAGIC;
260 
261 	/*
262 	 * Current versions of glibc do not correctly handle the
263 	 * case where f_frsize != f_bsize.  Eventually we want to
264 	 * report the value of wtmult in this field.
265 	 */
266 	buf->f_frsize = dentry->d_sb->s_blocksize;
267 
268 	/*
269 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
270 	 * are reported in units of f_frsize.  Linux hasn't had
271 	 * an f_frsize field in its statfs struct until recently,
272 	 * thus historically Linux's sys_statfs reports these
273 	 * fields in units of f_bsize.
274 	 */
275 	buf->f_bsize = dentry->d_sb->s_blocksize;
276 	blockbits = dentry->d_sb->s_blocksize_bits;
277 	blockres = (1 << blockbits) - 1;
278 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
279 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
280 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
281 
282 	buf->f_files = res.tfiles;
283 	buf->f_ffree = res.afiles;
284 
285 	buf->f_namelen = server->namelen;
286 
287 	return 0;
288 
289  out_err:
290 	dprintk("%s: statfs error = %d\n", __func__, -error);
291 	return error;
292 }
293 EXPORT_SYMBOL_GPL(nfs_statfs);
294 
295 /*
296  * Map the security flavour number to a name
297  */
298 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
299 {
300 	static const struct {
301 		rpc_authflavor_t flavour;
302 		const char *str;
303 	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
304 		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
305 		{ RPC_AUTH_NULL, "null" },
306 		{ RPC_AUTH_UNIX, "sys" },
307 		{ RPC_AUTH_GSS_KRB5, "krb5" },
308 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
309 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
310 		{ RPC_AUTH_GSS_LKEY, "lkey" },
311 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
312 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
313 		{ RPC_AUTH_GSS_SPKM, "spkm" },
314 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
315 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
316 		{ UINT_MAX, "unknown" }
317 	};
318 	int i;
319 
320 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
321 		if (sec_flavours[i].flavour == flavour)
322 			break;
323 	}
324 	return sec_flavours[i].str;
325 }
326 
327 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
328 				  int showdefaults)
329 {
330 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
331 	char *proto = NULL;
332 
333 	switch (sap->sa_family) {
334 	case AF_INET:
335 		switch (nfss->mountd_protocol) {
336 		case IPPROTO_UDP:
337 			proto = RPCBIND_NETID_UDP;
338 			break;
339 		case IPPROTO_TCP:
340 			proto = RPCBIND_NETID_TCP;
341 			break;
342 		}
343 		break;
344 	case AF_INET6:
345 		switch (nfss->mountd_protocol) {
346 		case IPPROTO_UDP:
347 			proto = RPCBIND_NETID_UDP6;
348 			break;
349 		case IPPROTO_TCP:
350 			proto = RPCBIND_NETID_TCP6;
351 			break;
352 		}
353 		break;
354 	}
355 	if (proto || showdefaults)
356 		seq_printf(m, ",mountproto=%s", proto ?: "auto");
357 }
358 
359 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
360 				    int showdefaults)
361 {
362 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
363 
364 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
365 		return;
366 
367 	switch (sap->sa_family) {
368 	case AF_INET: {
369 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
370 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
371 		break;
372 	}
373 	case AF_INET6: {
374 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
375 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
376 		break;
377 	}
378 	default:
379 		if (showdefaults)
380 			seq_puts(m, ",mountaddr=unspecified");
381 	}
382 
383 	if (nfss->mountd_version || showdefaults)
384 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
385 	if ((nfss->mountd_port &&
386 		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
387 		showdefaults)
388 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
389 
390 	nfs_show_mountd_netid(m, nfss, showdefaults);
391 }
392 
393 #if IS_ENABLED(CONFIG_NFS_V4)
394 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
395 				    int showdefaults)
396 {
397 	struct nfs_client *clp = nfss->nfs_client;
398 
399 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
400 }
401 #else
402 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
403 				    int showdefaults)
404 {
405 }
406 #endif
407 
408 static void nfs_show_nfs_version(struct seq_file *m,
409 		unsigned int version,
410 		unsigned int minorversion)
411 {
412 	seq_printf(m, ",vers=%u", version);
413 	if (version == 4)
414 		seq_printf(m, ".%u", minorversion);
415 }
416 
417 /*
418  * Describe the mount options in force on this server representation
419  */
420 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
421 				   int showdefaults)
422 {
423 	static const struct proc_nfs_info {
424 		int flag;
425 		const char *str;
426 		const char *nostr;
427 	} nfs_info[] = {
428 		{ NFS_MOUNT_SOFT, ",soft", "" },
429 		{ NFS_MOUNT_SOFTERR, ",softerr", "" },
430 		{ NFS_MOUNT_SOFTREVAL, ",softreval", "" },
431 		{ NFS_MOUNT_POSIX, ",posix", "" },
432 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
433 		{ NFS_MOUNT_NOAC, ",noac", "" },
434 		{ NFS_MOUNT_NONLM, ",nolock", "" },
435 		{ NFS_MOUNT_NOACL, ",noacl", "" },
436 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
437 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
438 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
439 		{ 0, NULL, NULL }
440 	};
441 	const struct proc_nfs_info *nfs_infop;
442 	struct nfs_client *clp = nfss->nfs_client;
443 	u32 version = clp->rpc_ops->version;
444 	int local_flock, local_fcntl;
445 
446 	nfs_show_nfs_version(m, version, clp->cl_minorversion);
447 	seq_printf(m, ",rsize=%u", nfss->rsize);
448 	seq_printf(m, ",wsize=%u", nfss->wsize);
449 	if (nfss->bsize != 0)
450 		seq_printf(m, ",bsize=%u", nfss->bsize);
451 	seq_printf(m, ",namlen=%u", nfss->namelen);
452 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
453 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
454 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
455 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
456 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
457 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
458 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
459 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
460 	if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
461 			seq_puts(m, ",hard");
462 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
463 		if (nfss->flags & nfs_infop->flag)
464 			seq_puts(m, nfs_infop->str);
465 		else
466 			seq_puts(m, nfs_infop->nostr);
467 	}
468 	rcu_read_lock();
469 	seq_printf(m, ",proto=%s",
470 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
471 	rcu_read_unlock();
472 	if (clp->cl_nconnect > 0)
473 		seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
474 	if (version == 4) {
475 		if (nfss->port != NFS_PORT)
476 			seq_printf(m, ",port=%u", nfss->port);
477 	} else
478 		if (nfss->port)
479 			seq_printf(m, ",port=%u", nfss->port);
480 
481 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
482 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
483 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
484 
485 	if (version != 4)
486 		nfs_show_mountd_options(m, nfss, showdefaults);
487 	else
488 		nfs_show_nfsv4_options(m, nfss, showdefaults);
489 
490 	if (nfss->options & NFS_OPTION_FSCACHE)
491 		seq_puts(m, ",fsc");
492 
493 	if (nfss->options & NFS_OPTION_MIGRATION)
494 		seq_puts(m, ",migration");
495 
496 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
497 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
498 			seq_puts(m, ",lookupcache=none");
499 		else
500 			seq_puts(m, ",lookupcache=pos");
501 	}
502 
503 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
504 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
505 
506 	if (!local_flock && !local_fcntl)
507 		seq_puts(m, ",local_lock=none");
508 	else if (local_flock && local_fcntl)
509 		seq_puts(m, ",local_lock=all");
510 	else if (local_flock)
511 		seq_puts(m, ",local_lock=flock");
512 	else
513 		seq_puts(m, ",local_lock=posix");
514 }
515 
516 /*
517  * Describe the mount options on this VFS mountpoint
518  */
519 int nfs_show_options(struct seq_file *m, struct dentry *root)
520 {
521 	struct nfs_server *nfss = NFS_SB(root->d_sb);
522 
523 	nfs_show_mount_options(m, nfss, 0);
524 
525 	rcu_read_lock();
526 	seq_printf(m, ",addr=%s",
527 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
528 							RPC_DISPLAY_ADDR));
529 	rcu_read_unlock();
530 
531 	return 0;
532 }
533 EXPORT_SYMBOL_GPL(nfs_show_options);
534 
535 #if IS_ENABLED(CONFIG_NFS_V4)
536 static void show_lease(struct seq_file *m, struct nfs_server *server)
537 {
538 	struct nfs_client *clp = server->nfs_client;
539 	unsigned long expire;
540 
541 	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
542 	expire = clp->cl_last_renewal + clp->cl_lease_time;
543 	seq_printf(m, ",lease_expired=%ld",
544 		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
545 }
546 #ifdef CONFIG_NFS_V4_1
547 static void show_sessions(struct seq_file *m, struct nfs_server *server)
548 {
549 	if (nfs4_has_session(server->nfs_client))
550 		seq_puts(m, ",sessions");
551 }
552 #else
553 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
554 #endif
555 #endif
556 
557 #ifdef CONFIG_NFS_V4_1
558 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
559 {
560 	seq_printf(m, ",pnfs=");
561 	if (server->pnfs_curr_ld)
562 		seq_printf(m, "%s", server->pnfs_curr_ld->name);
563 	else
564 		seq_printf(m, "not configured");
565 }
566 
567 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
568 {
569 	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
570 		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
571 		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
572 			   "date='%llu,%u'",
573 			   impl_id->name, impl_id->domain,
574 			   impl_id->date.seconds, impl_id->date.nseconds);
575 	}
576 }
577 #else
578 #if IS_ENABLED(CONFIG_NFS_V4)
579 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
580 {
581 }
582 #endif
583 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
584 {
585 }
586 #endif
587 
588 int nfs_show_devname(struct seq_file *m, struct dentry *root)
589 {
590 	char *page = (char *) __get_free_page(GFP_KERNEL);
591 	char *devname, *dummy;
592 	int err = 0;
593 	if (!page)
594 		return -ENOMEM;
595 	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
596 	if (IS_ERR(devname))
597 		err = PTR_ERR(devname);
598 	else
599 		seq_escape(m, devname, " \t\n\\");
600 	free_page((unsigned long)page);
601 	return err;
602 }
603 EXPORT_SYMBOL_GPL(nfs_show_devname);
604 
605 int nfs_show_path(struct seq_file *m, struct dentry *dentry)
606 {
607 	seq_puts(m, "/");
608 	return 0;
609 }
610 EXPORT_SYMBOL_GPL(nfs_show_path);
611 
612 /*
613  * Present statistical information for this VFS mountpoint
614  */
615 int nfs_show_stats(struct seq_file *m, struct dentry *root)
616 {
617 	int i, cpu;
618 	struct nfs_server *nfss = NFS_SB(root->d_sb);
619 	struct rpc_auth *auth = nfss->client->cl_auth;
620 	struct nfs_iostats totals = { };
621 
622 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
623 
624 	/*
625 	 * Display all mount option settings
626 	 */
627 	seq_puts(m, "\n\topts:\t");
628 	seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
629 	seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
630 	seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
631 	seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
632 	nfs_show_mount_options(m, nfss, 1);
633 
634 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
635 
636 	show_implementation_id(m, nfss);
637 
638 	seq_puts(m, "\n\tcaps:\t");
639 	seq_printf(m, "caps=0x%x", nfss->caps);
640 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
641 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
642 	seq_printf(m, ",bsize=%u", nfss->bsize);
643 	seq_printf(m, ",namlen=%u", nfss->namelen);
644 
645 #if IS_ENABLED(CONFIG_NFS_V4)
646 	if (nfss->nfs_client->rpc_ops->version == 4) {
647 		seq_puts(m, "\n\tnfsv4:\t");
648 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
649 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
650 		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
651 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
652 		show_sessions(m, nfss);
653 		show_pnfs(m, nfss);
654 		show_lease(m, nfss);
655 	}
656 #endif
657 
658 	/*
659 	 * Display security flavor in effect for this mount
660 	 */
661 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
662 	if (auth->au_flavor)
663 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
664 
665 	/*
666 	 * Display superblock I/O counters
667 	 */
668 	for_each_possible_cpu(cpu) {
669 		struct nfs_iostats *stats;
670 
671 		preempt_disable();
672 		stats = per_cpu_ptr(nfss->io_stats, cpu);
673 
674 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
675 			totals.events[i] += stats->events[i];
676 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
677 			totals.bytes[i] += stats->bytes[i];
678 #ifdef CONFIG_NFS_FSCACHE
679 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
680 			totals.fscache[i] += stats->fscache[i];
681 #endif
682 
683 		preempt_enable();
684 	}
685 
686 	seq_puts(m, "\n\tevents:\t");
687 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
688 		seq_printf(m, "%lu ", totals.events[i]);
689 	seq_puts(m, "\n\tbytes:\t");
690 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
691 		seq_printf(m, "%Lu ", totals.bytes[i]);
692 #ifdef CONFIG_NFS_FSCACHE
693 	if (nfss->options & NFS_OPTION_FSCACHE) {
694 		seq_puts(m, "\n\tfsc:\t");
695 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
696 			seq_printf(m, "%Lu ", totals.fscache[i]);
697 	}
698 #endif
699 	seq_putc(m, '\n');
700 
701 	rpc_clnt_show_stats(m, nfss->client);
702 
703 	return 0;
704 }
705 EXPORT_SYMBOL_GPL(nfs_show_stats);
706 
707 /*
708  * Begin unmount by attempting to remove all automounted mountpoints we added
709  * in response to xdev traversals and referrals
710  */
711 void nfs_umount_begin(struct super_block *sb)
712 {
713 	struct nfs_server *server;
714 	struct rpc_clnt *rpc;
715 
716 	server = NFS_SB(sb);
717 	/* -EIO all pending I/O */
718 	rpc = server->client_acl;
719 	if (!IS_ERR(rpc))
720 		rpc_killall_tasks(rpc);
721 	rpc = server->client;
722 	if (!IS_ERR(rpc))
723 		rpc_killall_tasks(rpc);
724 }
725 EXPORT_SYMBOL_GPL(nfs_umount_begin);
726 
727 /*
728  * Return true if 'match' is in auth_info or auth_info is empty.
729  * Return false otherwise.
730  */
731 bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
732 			 rpc_authflavor_t match)
733 {
734 	int i;
735 
736 	if (!auth_info->flavor_len)
737 		return true;
738 
739 	for (i = 0; i < auth_info->flavor_len; i++) {
740 		if (auth_info->flavors[i] == match)
741 			return true;
742 	}
743 	return false;
744 }
745 EXPORT_SYMBOL_GPL(nfs_auth_info_match);
746 
747 /*
748  * Ensure that a specified authtype in ctx->auth_info is supported by
749  * the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
750  * -EACCES if not.
751  */
752 static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
753 				  rpc_authflavor_t *server_authlist,
754 				  unsigned int count)
755 {
756 	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
757 	bool found_auth_null = false;
758 	unsigned int i;
759 
760 	/*
761 	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
762 	 * must be in the list returned by the server.
763 	 *
764 	 * AUTH_NULL has a special meaning when it's in the server list - it
765 	 * means that the server will ignore the rpc creds, so any flavor
766 	 * can be used but still use the sec= that was specified.
767 	 *
768 	 * Note also that the MNT procedure in MNTv1 does not return a list
769 	 * of supported security flavors. In this case, nfs_mount() fabricates
770 	 * a security flavor list containing just AUTH_NULL.
771 	 */
772 	for (i = 0; i < count; i++) {
773 		flavor = server_authlist[i];
774 
775 		if (nfs_auth_info_match(&ctx->auth_info, flavor))
776 			goto out;
777 
778 		if (flavor == RPC_AUTH_NULL)
779 			found_auth_null = true;
780 	}
781 
782 	if (found_auth_null) {
783 		flavor = ctx->auth_info.flavors[0];
784 		goto out;
785 	}
786 
787 	dfprintk(MOUNT,
788 		 "NFS: specified auth flavors not supported by server\n");
789 	return -EACCES;
790 
791 out:
792 	ctx->selected_flavor = flavor;
793 	dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
794 	return 0;
795 }
796 
797 /*
798  * Use the remote server's MOUNT service to request the NFS file handle
799  * corresponding to the provided path.
800  */
801 static int nfs_request_mount(struct fs_context *fc,
802 			     struct nfs_fh *root_fh,
803 			     rpc_authflavor_t *server_authlist,
804 			     unsigned int *server_authlist_len)
805 {
806 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
807 	struct nfs_mount_request request = {
808 		.sap		= (struct sockaddr *)
809 						&ctx->mount_server.address,
810 		.dirpath	= ctx->nfs_server.export_path,
811 		.protocol	= ctx->mount_server.protocol,
812 		.fh		= root_fh,
813 		.noresvport	= ctx->flags & NFS_MOUNT_NORESVPORT,
814 		.auth_flav_len	= server_authlist_len,
815 		.auth_flavs	= server_authlist,
816 		.net		= fc->net_ns,
817 	};
818 	int status;
819 
820 	if (ctx->mount_server.version == 0) {
821 		switch (ctx->version) {
822 			default:
823 				ctx->mount_server.version = NFS_MNT3_VERSION;
824 				break;
825 			case 2:
826 				ctx->mount_server.version = NFS_MNT_VERSION;
827 		}
828 	}
829 	request.version = ctx->mount_server.version;
830 
831 	if (ctx->mount_server.hostname)
832 		request.hostname = ctx->mount_server.hostname;
833 	else
834 		request.hostname = ctx->nfs_server.hostname;
835 
836 	/*
837 	 * Construct the mount server's address.
838 	 */
839 	if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
840 		memcpy(request.sap, &ctx->nfs_server.address,
841 		       ctx->nfs_server.addrlen);
842 		ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
843 	}
844 	request.salen = ctx->mount_server.addrlen;
845 	nfs_set_port(request.sap, &ctx->mount_server.port, 0);
846 
847 	/*
848 	 * Now ask the mount server to map our export path
849 	 * to a file handle.
850 	 */
851 	status = nfs_mount(&request);
852 	if (status != 0) {
853 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
854 				request.hostname, status);
855 		return status;
856 	}
857 
858 	return 0;
859 }
860 
861 static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
862 {
863 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
864 	int status;
865 	unsigned int i;
866 	bool tried_auth_unix = false;
867 	bool auth_null_in_list = false;
868 	struct nfs_server *server = ERR_PTR(-EACCES);
869 	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
870 	unsigned int authlist_len = ARRAY_SIZE(authlist);
871 
872 	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
873 	if (status)
874 		return ERR_PTR(status);
875 
876 	/*
877 	 * Was a sec= authflavor specified in the options? First, verify
878 	 * whether the server supports it, and then just try to use it if so.
879 	 */
880 	if (ctx->auth_info.flavor_len > 0) {
881 		status = nfs_verify_authflavors(ctx, authlist, authlist_len);
882 		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
883 			 ctx->selected_flavor);
884 		if (status)
885 			return ERR_PTR(status);
886 		return ctx->nfs_mod->rpc_ops->create_server(fc);
887 	}
888 
889 	/*
890 	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
891 	 * SHOULD prefer the flavor listed first. However, some servers list
892 	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
893 	 */
894 	for (i = 0; i < authlist_len; ++i) {
895 		rpc_authflavor_t flavor;
896 		struct rpcsec_gss_info info;
897 
898 		flavor = authlist[i];
899 		switch (flavor) {
900 		case RPC_AUTH_UNIX:
901 			tried_auth_unix = true;
902 			break;
903 		case RPC_AUTH_NULL:
904 			auth_null_in_list = true;
905 			continue;
906 		default:
907 			if (rpcauth_get_gssinfo(flavor, &info) != 0)
908 				continue;
909 			break;
910 		}
911 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
912 		ctx->selected_flavor = flavor;
913 		server = ctx->nfs_mod->rpc_ops->create_server(fc);
914 		if (!IS_ERR(server))
915 			return server;
916 	}
917 
918 	/*
919 	 * Nothing we tried so far worked. At this point, give up if we've
920 	 * already tried AUTH_UNIX or if the server's list doesn't contain
921 	 * AUTH_NULL
922 	 */
923 	if (tried_auth_unix || !auth_null_in_list)
924 		return server;
925 
926 	/* Last chance! Try AUTH_UNIX */
927 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
928 	ctx->selected_flavor = RPC_AUTH_UNIX;
929 	return ctx->nfs_mod->rpc_ops->create_server(fc);
930 }
931 
932 int nfs_try_get_tree(struct fs_context *fc)
933 {
934 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
935 
936 	if (ctx->need_mount)
937 		ctx->server = nfs_try_mount_request(fc);
938 	else
939 		ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
940 
941 	return nfs_get_tree_common(fc);
942 }
943 EXPORT_SYMBOL_GPL(nfs_try_get_tree);
944 
945 
946 #define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
947 		| NFS_MOUNT_SECURE \
948 		| NFS_MOUNT_TCP \
949 		| NFS_MOUNT_VER3 \
950 		| NFS_MOUNT_KERBEROS \
951 		| NFS_MOUNT_NONLM \
952 		| NFS_MOUNT_BROKEN_SUID \
953 		| NFS_MOUNT_STRICTLOCK \
954 		| NFS_MOUNT_LEGACY_INTERFACE)
955 
956 #define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
957 		~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
958 
959 static int
960 nfs_compare_remount_data(struct nfs_server *nfss,
961 			 struct nfs_fs_context *ctx)
962 {
963 	if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
964 	    ctx->rsize != nfss->rsize ||
965 	    ctx->wsize != nfss->wsize ||
966 	    ctx->version != nfss->nfs_client->rpc_ops->version ||
967 	    ctx->minorversion != nfss->nfs_client->cl_minorversion ||
968 	    ctx->retrans != nfss->client->cl_timeout->to_retries ||
969 	    !nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
970 	    ctx->acregmin != nfss->acregmin / HZ ||
971 	    ctx->acregmax != nfss->acregmax / HZ ||
972 	    ctx->acdirmin != nfss->acdirmin / HZ ||
973 	    ctx->acdirmax != nfss->acdirmax / HZ ||
974 	    ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
975 	    (ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
976 	    ctx->nfs_server.port != nfss->port ||
977 	    ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
978 	    !rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
979 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
980 		return -EINVAL;
981 
982 	return 0;
983 }
984 
985 int nfs_reconfigure(struct fs_context *fc)
986 {
987 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
988 	struct super_block *sb = fc->root->d_sb;
989 	struct nfs_server *nfss = sb->s_fs_info;
990 
991 	sync_filesystem(sb);
992 
993 	/*
994 	 * Userspace mount programs that send binary options generally send
995 	 * them populated with default values. We have no way to know which
996 	 * ones were explicitly specified. Fall back to legacy behavior and
997 	 * just return success.
998 	 */
999 	if (ctx->skip_reconfig_option_check)
1000 		return 0;
1001 
1002 	/*
1003 	 * noac is a special case. It implies -o sync, but that's not
1004 	 * necessarily reflected in the mtab options. reconfigure_super
1005 	 * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
1006 	 * remount options, so we have to explicitly reset it.
1007 	 */
1008 	if (ctx->flags & NFS_MOUNT_NOAC) {
1009 		fc->sb_flags |= SB_SYNCHRONOUS;
1010 		fc->sb_flags_mask |= SB_SYNCHRONOUS;
1011 	}
1012 
1013 	/* compare new mount options with old ones */
1014 	return nfs_compare_remount_data(nfss, ctx);
1015 }
1016 EXPORT_SYMBOL_GPL(nfs_reconfigure);
1017 
1018 /*
1019  * Finish setting up an NFS superblock
1020  */
1021 static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
1022 {
1023 	struct nfs_server *server = NFS_SB(sb);
1024 
1025 	sb->s_blocksize_bits = 0;
1026 	sb->s_blocksize = 0;
1027 	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
1028 	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
1029 	if (ctx && ctx->bsize)
1030 		sb->s_blocksize = nfs_block_size(ctx->bsize, &sb->s_blocksize_bits);
1031 
1032 	if (server->nfs_client->rpc_ops->version != 2) {
1033 		/* The VFS shouldn't apply the umask to mode bits. We will do
1034 		 * so ourselves when necessary.
1035 		 */
1036 		sb->s_flags |= SB_POSIXACL;
1037 		sb->s_time_gran = 1;
1038 		sb->s_export_op = &nfs_export_ops;
1039 	} else
1040 		sb->s_time_gran = 1000;
1041 
1042 	if (server->nfs_client->rpc_ops->version != 4) {
1043 		sb->s_time_min = 0;
1044 		sb->s_time_max = U32_MAX;
1045 	} else {
1046 		sb->s_time_min = S64_MIN;
1047 		sb->s_time_max = S64_MAX;
1048 	}
1049 
1050 	sb->s_magic = NFS_SUPER_MAGIC;
1051 
1052 	/* We probably want something more informative here */
1053 	snprintf(sb->s_id, sizeof(sb->s_id),
1054 		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1055 
1056 	if (sb->s_blocksize == 0)
1057 		sb->s_blocksize = nfs_block_bits(server->wsize,
1058 						 &sb->s_blocksize_bits);
1059 
1060 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1061 }
1062 
1063 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b,
1064 				     const struct fs_context *fc)
1065 {
1066 	const struct nfs_server *a = s->s_fs_info;
1067 	const struct rpc_clnt *clnt_a = a->client;
1068 	const struct rpc_clnt *clnt_b = b->client;
1069 
1070 	if ((s->s_flags & NFS_SB_MASK) != (fc->sb_flags & NFS_SB_MASK))
1071 		goto Ebusy;
1072 	if (a->nfs_client != b->nfs_client)
1073 		goto Ebusy;
1074 	if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
1075 		goto Ebusy;
1076 	if (a->wsize != b->wsize)
1077 		goto Ebusy;
1078 	if (a->rsize != b->rsize)
1079 		goto Ebusy;
1080 	if (a->acregmin != b->acregmin)
1081 		goto Ebusy;
1082 	if (a->acregmax != b->acregmax)
1083 		goto Ebusy;
1084 	if (a->acdirmin != b->acdirmin)
1085 		goto Ebusy;
1086 	if (a->acdirmax != b->acdirmax)
1087 		goto Ebusy;
1088 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1089 		goto Ebusy;
1090 	return 1;
1091 Ebusy:
1092 	return 0;
1093 }
1094 
1095 static int nfs_set_super(struct super_block *s, struct fs_context *fc)
1096 {
1097 	struct nfs_server *server = fc->s_fs_info;
1098 	int ret;
1099 
1100 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
1101 	ret = set_anon_super(s, server);
1102 	if (ret == 0)
1103 		server->s_dev = s->s_dev;
1104 	return ret;
1105 }
1106 
1107 static int nfs_compare_super_address(struct nfs_server *server1,
1108 				     struct nfs_server *server2)
1109 {
1110 	struct sockaddr *sap1, *sap2;
1111 	struct rpc_xprt *xprt1 = server1->client->cl_xprt;
1112 	struct rpc_xprt *xprt2 = server2->client->cl_xprt;
1113 
1114 	if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
1115 		return 0;
1116 
1117 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1118 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1119 
1120 	if (sap1->sa_family != sap2->sa_family)
1121 		return 0;
1122 
1123 	switch (sap1->sa_family) {
1124 	case AF_INET: {
1125 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1126 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1127 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1128 			return 0;
1129 		if (sin1->sin_port != sin2->sin_port)
1130 			return 0;
1131 		break;
1132 	}
1133 	case AF_INET6: {
1134 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1135 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1136 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1137 			return 0;
1138 		if (sin1->sin6_port != sin2->sin6_port)
1139 			return 0;
1140 		break;
1141 	}
1142 	default:
1143 		return 0;
1144 	}
1145 
1146 	return 1;
1147 }
1148 
1149 static int nfs_compare_userns(const struct nfs_server *old,
1150 		const struct nfs_server *new)
1151 {
1152 	const struct user_namespace *oldns = &init_user_ns;
1153 	const struct user_namespace *newns = &init_user_ns;
1154 
1155 	if (old->client && old->client->cl_cred)
1156 		oldns = old->client->cl_cred->user_ns;
1157 	if (new->client && new->client->cl_cred)
1158 		newns = new->client->cl_cred->user_ns;
1159 	if (oldns != newns)
1160 		return 0;
1161 	return 1;
1162 }
1163 
1164 static int nfs_compare_super(struct super_block *sb, struct fs_context *fc)
1165 {
1166 	struct nfs_server *server = fc->s_fs_info, *old = NFS_SB(sb);
1167 
1168 	if (!nfs_compare_super_address(old, server))
1169 		return 0;
1170 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1171 	if (old->flags & NFS_MOUNT_UNSHARED)
1172 		return 0;
1173 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1174 		return 0;
1175 	if (!nfs_compare_userns(old, server))
1176 		return 0;
1177 	return nfs_compare_mount_options(sb, server, fc);
1178 }
1179 
1180 #ifdef CONFIG_NFS_FSCACHE
1181 static void nfs_get_cache_cookie(struct super_block *sb,
1182 				 struct nfs_fs_context *ctx)
1183 {
1184 	struct nfs_server *nfss = NFS_SB(sb);
1185 	char *uniq = NULL;
1186 	int ulen = 0;
1187 
1188 	nfss->fscache_key = NULL;
1189 	nfss->fscache = NULL;
1190 
1191 	if (!ctx)
1192 		return;
1193 
1194 	if (ctx->clone_data.sb) {
1195 		struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
1196 		if (!(mnt_s->options & NFS_OPTION_FSCACHE))
1197 			return;
1198 		if (mnt_s->fscache_key) {
1199 			uniq = mnt_s->fscache_key->key.uniquifier;
1200 			ulen = mnt_s->fscache_key->key.uniq_len;
1201 		}
1202 	} else {
1203 		if (!(ctx->options & NFS_OPTION_FSCACHE))
1204 			return;
1205 		if (ctx->fscache_uniq) {
1206 			uniq = ctx->fscache_uniq;
1207 			ulen = strlen(ctx->fscache_uniq);
1208 		}
1209 	}
1210 
1211 	nfs_fscache_get_super_cookie(sb, uniq, ulen);
1212 }
1213 #else
1214 static void nfs_get_cache_cookie(struct super_block *sb,
1215 				 struct nfs_fs_context *ctx)
1216 {
1217 }
1218 #endif
1219 
1220 int nfs_get_tree_common(struct fs_context *fc)
1221 {
1222 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1223 	struct super_block *s;
1224 	int (*compare_super)(struct super_block *, struct fs_context *) = nfs_compare_super;
1225 	struct nfs_server *server = ctx->server;
1226 	int error;
1227 
1228 	ctx->server = NULL;
1229 	if (IS_ERR(server))
1230 		return PTR_ERR(server);
1231 
1232 	if (server->flags & NFS_MOUNT_UNSHARED)
1233 		compare_super = NULL;
1234 
1235 	/* -o noac implies -o sync */
1236 	if (server->flags & NFS_MOUNT_NOAC)
1237 		fc->sb_flags |= SB_SYNCHRONOUS;
1238 
1239 	if (ctx->clone_data.sb)
1240 		if (ctx->clone_data.sb->s_flags & SB_SYNCHRONOUS)
1241 			fc->sb_flags |= SB_SYNCHRONOUS;
1242 
1243 	if (server->caps & NFS_CAP_SECURITY_LABEL)
1244 		fc->lsm_flags |= SECURITY_LSM_NATIVE_LABELS;
1245 
1246 	/* Get a superblock - note that we may end up sharing one that already exists */
1247 	fc->s_fs_info = server;
1248 	s = sget_fc(fc, compare_super, nfs_set_super);
1249 	fc->s_fs_info = NULL;
1250 	if (IS_ERR(s)) {
1251 		error = PTR_ERR(s);
1252 		nfs_errorf(fc, "NFS: Couldn't get superblock");
1253 		goto out_err_nosb;
1254 	}
1255 
1256 	if (s->s_fs_info != server) {
1257 		nfs_free_server(server);
1258 		server = NULL;
1259 	} else {
1260 		error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
1261 					     MINOR(server->s_dev));
1262 		if (error)
1263 			goto error_splat_super;
1264 		s->s_bdi->io_pages = server->rpages;
1265 		server->super = s;
1266 	}
1267 
1268 	if (!s->s_root) {
1269 		unsigned bsize = ctx->clone_data.inherited_bsize;
1270 		/* initial superblock/root creation */
1271 		nfs_fill_super(s, ctx);
1272 		if (bsize) {
1273 			s->s_blocksize_bits = bsize;
1274 			s->s_blocksize = 1U << bsize;
1275 		}
1276 		nfs_get_cache_cookie(s, ctx);
1277 	}
1278 
1279 	error = nfs_get_root(s, fc);
1280 	if (error < 0) {
1281 		nfs_errorf(fc, "NFS: Couldn't get root dentry");
1282 		goto error_splat_super;
1283 	}
1284 
1285 	s->s_flags |= SB_ACTIVE;
1286 	error = 0;
1287 
1288 out:
1289 	return error;
1290 
1291 out_err_nosb:
1292 	nfs_free_server(server);
1293 	goto out;
1294 error_splat_super:
1295 	deactivate_locked_super(s);
1296 	goto out;
1297 }
1298 
1299 /*
1300  * Destroy an NFS2/3 superblock
1301  */
1302 void nfs_kill_super(struct super_block *s)
1303 {
1304 	struct nfs_server *server = NFS_SB(s);
1305 	dev_t dev = s->s_dev;
1306 
1307 	generic_shutdown_super(s);
1308 
1309 	nfs_fscache_release_super_cookie(s);
1310 
1311 	nfs_free_server(server);
1312 	free_anon_bdev(dev);
1313 }
1314 EXPORT_SYMBOL_GPL(nfs_kill_super);
1315 
1316 #if IS_ENABLED(CONFIG_NFS_V4)
1317 
1318 /*
1319  * NFS v4 module parameters need to stay in the
1320  * NFS client for backwards compatibility
1321  */
1322 unsigned int nfs_callback_set_tcpport;
1323 unsigned short nfs_callback_nr_threads;
1324 /* Default cache timeout is 10 minutes */
1325 unsigned int nfs_idmap_cache_timeout = 600;
1326 /* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
1327 bool nfs4_disable_idmapping = true;
1328 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
1329 unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
1330 unsigned short send_implementation_id = 1;
1331 char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
1332 bool recover_lost_locks = false;
1333 
1334 EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
1335 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
1336 EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
1337 EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
1338 EXPORT_SYMBOL_GPL(max_session_slots);
1339 EXPORT_SYMBOL_GPL(max_session_cb_slots);
1340 EXPORT_SYMBOL_GPL(send_implementation_id);
1341 EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
1342 EXPORT_SYMBOL_GPL(recover_lost_locks);
1343 
1344 #define NFS_CALLBACK_MAXPORTNR (65535U)
1345 
1346 static int param_set_portnr(const char *val, const struct kernel_param *kp)
1347 {
1348 	unsigned long num;
1349 	int ret;
1350 
1351 	if (!val)
1352 		return -EINVAL;
1353 	ret = kstrtoul(val, 0, &num);
1354 	if (ret || num > NFS_CALLBACK_MAXPORTNR)
1355 		return -EINVAL;
1356 	*((unsigned int *)kp->arg) = num;
1357 	return 0;
1358 }
1359 static const struct kernel_param_ops param_ops_portnr = {
1360 	.set = param_set_portnr,
1361 	.get = param_get_uint,
1362 };
1363 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
1364 
1365 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1366 module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
1367 MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
1368 		"assigned to the NFSv4 callback channels.");
1369 module_param(nfs_idmap_cache_timeout, int, 0644);
1370 module_param(nfs4_disable_idmapping, bool, 0644);
1371 module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
1372 			NFS4_CLIENT_ID_UNIQ_LEN, 0600);
1373 MODULE_PARM_DESC(nfs4_disable_idmapping,
1374 		"Turn off NFSv4 idmapping when using 'sec=sys'");
1375 module_param(max_session_slots, ushort, 0644);
1376 MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
1377 		"requests the client will negotiate");
1378 module_param(max_session_cb_slots, ushort, 0644);
1379 MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
1380 		"callbacks the client will process for a given server");
1381 module_param(send_implementation_id, ushort, 0644);
1382 MODULE_PARM_DESC(send_implementation_id,
1383 		"Send implementation ID with NFSv4.1 exchange_id");
1384 MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
1385 
1386 module_param(recover_lost_locks, bool, 0644);
1387 MODULE_PARM_DESC(recover_lost_locks,
1388 		 "If the server reports that a lock might be lost, "
1389 		 "try to recover it risking data corruption.");
1390 
1391 
1392 #endif /* CONFIG_NFS_V4 */
1393