xref: /openbmc/linux/fs/nfs/super.c (revision e65e175b)
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 #ifdef CONFIG_NFS_V4_2
90 static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
91 	.sco_sb_deactive = nfs_sb_deactive,
92 };
93 #endif
94 
95 #if IS_ENABLED(CONFIG_NFS_V4)
96 static int __init register_nfs4_fs(void)
97 {
98 	return register_filesystem(&nfs4_fs_type);
99 }
100 
101 static void unregister_nfs4_fs(void)
102 {
103 	unregister_filesystem(&nfs4_fs_type);
104 }
105 #else
106 static int __init register_nfs4_fs(void)
107 {
108 	return 0;
109 }
110 
111 static void unregister_nfs4_fs(void)
112 {
113 }
114 #endif
115 
116 #ifdef CONFIG_NFS_V4_2
117 static void nfs_ssc_register_ops(void)
118 {
119 	nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
120 }
121 
122 static void nfs_ssc_unregister_ops(void)
123 {
124 	nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
125 }
126 #endif /* CONFIG_NFS_V4_2 */
127 
128 static struct shrinker acl_shrinker = {
129 	.count_objects	= nfs_access_cache_count,
130 	.scan_objects	= nfs_access_cache_scan,
131 	.seeks		= DEFAULT_SEEKS,
132 };
133 
134 /*
135  * Register the NFS filesystems
136  */
137 int __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 	ret = register_shrinker(&acl_shrinker, "nfs-acl");
153 	if (ret < 0)
154 		goto error_3;
155 #ifdef CONFIG_NFS_V4_2
156 	nfs_ssc_register_ops();
157 #endif
158 	return 0;
159 error_3:
160 	nfs_unregister_sysctl();
161 error_2:
162 	unregister_nfs4_fs();
163 error_1:
164 	unregister_filesystem(&nfs_fs_type);
165 error_0:
166 	return ret;
167 }
168 
169 /*
170  * Unregister the NFS filesystems
171  */
172 void __exit unregister_nfs_fs(void)
173 {
174 	unregister_shrinker(&acl_shrinker);
175 	nfs_unregister_sysctl();
176 	unregister_nfs4_fs();
177 #ifdef CONFIG_NFS_V4_2
178 	nfs_ssc_unregister_ops();
179 #endif
180 	unregister_filesystem(&nfs_fs_type);
181 }
182 
183 bool nfs_sb_active(struct super_block *sb)
184 {
185 	struct nfs_server *server = NFS_SB(sb);
186 
187 	if (!atomic_inc_not_zero(&sb->s_active))
188 		return false;
189 	if (atomic_inc_return(&server->active) != 1)
190 		atomic_dec(&sb->s_active);
191 	return true;
192 }
193 EXPORT_SYMBOL_GPL(nfs_sb_active);
194 
195 void nfs_sb_deactive(struct super_block *sb)
196 {
197 	struct nfs_server *server = NFS_SB(sb);
198 
199 	if (atomic_dec_and_test(&server->active))
200 		deactivate_super(sb);
201 }
202 EXPORT_SYMBOL_GPL(nfs_sb_deactive);
203 
204 static int __nfs_list_for_each_server(struct list_head *head,
205 		int (*fn)(struct nfs_server *, void *),
206 		void *data)
207 {
208 	struct nfs_server *server, *last = NULL;
209 	int ret = 0;
210 
211 	rcu_read_lock();
212 	list_for_each_entry_rcu(server, head, client_link) {
213 		if (!(server->super && nfs_sb_active(server->super)))
214 			continue;
215 		rcu_read_unlock();
216 		if (last)
217 			nfs_sb_deactive(last->super);
218 		last = server;
219 		ret = fn(server, data);
220 		if (ret)
221 			goto out;
222 		rcu_read_lock();
223 	}
224 	rcu_read_unlock();
225 out:
226 	if (last)
227 		nfs_sb_deactive(last->super);
228 	return ret;
229 }
230 
231 int nfs_client_for_each_server(struct nfs_client *clp,
232 		int (*fn)(struct nfs_server *, void *),
233 		void *data)
234 {
235 	return __nfs_list_for_each_server(&clp->cl_superblocks, fn, data);
236 }
237 EXPORT_SYMBOL_GPL(nfs_client_for_each_server);
238 
239 /*
240  * Deliver file system statistics to userspace
241  */
242 int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
243 {
244 	struct nfs_server *server = NFS_SB(dentry->d_sb);
245 	unsigned char blockbits;
246 	unsigned long blockres;
247 	struct nfs_fh *fh = NFS_FH(d_inode(dentry));
248 	struct nfs_fsstat res;
249 	int error = -ENOMEM;
250 
251 	res.fattr = nfs_alloc_fattr();
252 	if (res.fattr == NULL)
253 		goto out_err;
254 
255 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
256 	if (unlikely(error == -ESTALE)) {
257 		struct dentry *pd_dentry;
258 
259 		pd_dentry = dget_parent(dentry);
260 		nfs_zap_caches(d_inode(pd_dentry));
261 		dput(pd_dentry);
262 	}
263 	nfs_free_fattr(res.fattr);
264 	if (error < 0)
265 		goto out_err;
266 
267 	buf->f_type = NFS_SUPER_MAGIC;
268 
269 	/*
270 	 * Current versions of glibc do not correctly handle the
271 	 * case where f_frsize != f_bsize.  Eventually we want to
272 	 * report the value of wtmult in this field.
273 	 */
274 	buf->f_frsize = dentry->d_sb->s_blocksize;
275 
276 	/*
277 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
278 	 * are reported in units of f_frsize.  Linux hasn't had
279 	 * an f_frsize field in its statfs struct until recently,
280 	 * thus historically Linux's sys_statfs reports these
281 	 * fields in units of f_bsize.
282 	 */
283 	buf->f_bsize = dentry->d_sb->s_blocksize;
284 	blockbits = dentry->d_sb->s_blocksize_bits;
285 	blockres = (1 << blockbits) - 1;
286 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
287 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
288 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
289 
290 	buf->f_files = res.tfiles;
291 	buf->f_ffree = res.afiles;
292 
293 	buf->f_namelen = server->namelen;
294 
295 	return 0;
296 
297  out_err:
298 	dprintk("%s: statfs error = %d\n", __func__, -error);
299 	return error;
300 }
301 EXPORT_SYMBOL_GPL(nfs_statfs);
302 
303 /*
304  * Map the security flavour number to a name
305  */
306 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
307 {
308 	static const struct {
309 		rpc_authflavor_t flavour;
310 		const char *str;
311 	} sec_flavours[NFS_AUTH_INFO_MAX_FLAVORS] = {
312 		/* update NFS_AUTH_INFO_MAX_FLAVORS when this list changes! */
313 		{ RPC_AUTH_NULL, "null" },
314 		{ RPC_AUTH_UNIX, "sys" },
315 		{ RPC_AUTH_GSS_KRB5, "krb5" },
316 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
317 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
318 		{ RPC_AUTH_GSS_LKEY, "lkey" },
319 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
320 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
321 		{ RPC_AUTH_GSS_SPKM, "spkm" },
322 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
323 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
324 		{ UINT_MAX, "unknown" }
325 	};
326 	int i;
327 
328 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
329 		if (sec_flavours[i].flavour == flavour)
330 			break;
331 	}
332 	return sec_flavours[i].str;
333 }
334 
335 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
336 				  int showdefaults)
337 {
338 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
339 	char *proto = NULL;
340 
341 	switch (sap->sa_family) {
342 	case AF_INET:
343 		switch (nfss->mountd_protocol) {
344 		case IPPROTO_UDP:
345 			proto = RPCBIND_NETID_UDP;
346 			break;
347 		case IPPROTO_TCP:
348 			proto = RPCBIND_NETID_TCP;
349 			break;
350 		}
351 		break;
352 	case AF_INET6:
353 		switch (nfss->mountd_protocol) {
354 		case IPPROTO_UDP:
355 			proto = RPCBIND_NETID_UDP6;
356 			break;
357 		case IPPROTO_TCP:
358 			proto = RPCBIND_NETID_TCP6;
359 			break;
360 		}
361 		break;
362 	}
363 	if (proto || showdefaults)
364 		seq_printf(m, ",mountproto=%s", proto ?: "auto");
365 }
366 
367 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
368 				    int showdefaults)
369 {
370 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
371 
372 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
373 		return;
374 
375 	switch (sap->sa_family) {
376 	case AF_INET: {
377 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
378 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
379 		break;
380 	}
381 	case AF_INET6: {
382 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
383 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
384 		break;
385 	}
386 	default:
387 		if (showdefaults)
388 			seq_puts(m, ",mountaddr=unspecified");
389 	}
390 
391 	if (nfss->mountd_version || showdefaults)
392 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
393 	if ((nfss->mountd_port &&
394 		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
395 		showdefaults)
396 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
397 
398 	nfs_show_mountd_netid(m, nfss, showdefaults);
399 }
400 
401 #if IS_ENABLED(CONFIG_NFS_V4)
402 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
403 				    int showdefaults)
404 {
405 	struct nfs_client *clp = nfss->nfs_client;
406 
407 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
408 }
409 #else
410 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
411 				    int showdefaults)
412 {
413 }
414 #endif
415 
416 static void nfs_show_nfs_version(struct seq_file *m,
417 		unsigned int version,
418 		unsigned int minorversion)
419 {
420 	seq_printf(m, ",vers=%u", version);
421 	if (version == 4)
422 		seq_printf(m, ".%u", minorversion);
423 }
424 
425 /*
426  * Describe the mount options in force on this server representation
427  */
428 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
429 				   int showdefaults)
430 {
431 	static const struct proc_nfs_info {
432 		int flag;
433 		const char *str;
434 		const char *nostr;
435 	} nfs_info[] = {
436 		{ NFS_MOUNT_SOFT, ",soft", "" },
437 		{ NFS_MOUNT_SOFTERR, ",softerr", "" },
438 		{ NFS_MOUNT_SOFTREVAL, ",softreval", "" },
439 		{ NFS_MOUNT_POSIX, ",posix", "" },
440 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
441 		{ NFS_MOUNT_NOAC, ",noac", "" },
442 		{ NFS_MOUNT_NONLM, ",nolock", "" },
443 		{ NFS_MOUNT_NOACL, ",noacl", "" },
444 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
445 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
446 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
447 		{ 0, NULL, NULL }
448 	};
449 	const struct proc_nfs_info *nfs_infop;
450 	struct nfs_client *clp = nfss->nfs_client;
451 	u32 version = clp->rpc_ops->version;
452 	int local_flock, local_fcntl;
453 
454 	nfs_show_nfs_version(m, version, clp->cl_minorversion);
455 	seq_printf(m, ",rsize=%u", nfss->rsize);
456 	seq_printf(m, ",wsize=%u", nfss->wsize);
457 	if (nfss->bsize != 0)
458 		seq_printf(m, ",bsize=%u", nfss->bsize);
459 	seq_printf(m, ",namlen=%u", nfss->namelen);
460 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
461 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
462 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
463 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
464 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
465 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
466 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
467 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
468 	if (!(nfss->flags & (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR)))
469 			seq_puts(m, ",hard");
470 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
471 		if (nfss->flags & nfs_infop->flag)
472 			seq_puts(m, nfs_infop->str);
473 		else
474 			seq_puts(m, nfs_infop->nostr);
475 	}
476 	rcu_read_lock();
477 	seq_printf(m, ",proto=%s",
478 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
479 	rcu_read_unlock();
480 	if (clp->cl_nconnect > 0)
481 		seq_printf(m, ",nconnect=%u", clp->cl_nconnect);
482 	if (version == 4) {
483 		if (clp->cl_max_connect > 1)
484 			seq_printf(m, ",max_connect=%u", clp->cl_max_connect);
485 		if (nfss->port != NFS_PORT)
486 			seq_printf(m, ",port=%u", nfss->port);
487 	} else
488 		if (nfss->port)
489 			seq_printf(m, ",port=%u", nfss->port);
490 
491 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
492 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
493 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
494 
495 	if (version != 4)
496 		nfs_show_mountd_options(m, nfss, showdefaults);
497 	else
498 		nfs_show_nfsv4_options(m, nfss, showdefaults);
499 
500 	if (nfss->options & NFS_OPTION_FSCACHE)
501 		seq_puts(m, ",fsc");
502 
503 	if (nfss->options & NFS_OPTION_MIGRATION)
504 		seq_puts(m, ",migration");
505 
506 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
507 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
508 			seq_puts(m, ",lookupcache=none");
509 		else
510 			seq_puts(m, ",lookupcache=pos");
511 	}
512 
513 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
514 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
515 
516 	if (!local_flock && !local_fcntl)
517 		seq_puts(m, ",local_lock=none");
518 	else if (local_flock && local_fcntl)
519 		seq_puts(m, ",local_lock=all");
520 	else if (local_flock)
521 		seq_puts(m, ",local_lock=flock");
522 	else
523 		seq_puts(m, ",local_lock=posix");
524 
525 	if (nfss->flags & NFS_MOUNT_WRITE_EAGER) {
526 		if (nfss->flags & NFS_MOUNT_WRITE_WAIT)
527 			seq_puts(m, ",write=wait");
528 		else
529 			seq_puts(m, ",write=eager");
530 	}
531 }
532 
533 /*
534  * Describe the mount options on this VFS mountpoint
535  */
536 int nfs_show_options(struct seq_file *m, struct dentry *root)
537 {
538 	struct nfs_server *nfss = NFS_SB(root->d_sb);
539 
540 	nfs_show_mount_options(m, nfss, 0);
541 
542 	rcu_read_lock();
543 	seq_printf(m, ",addr=%s",
544 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
545 							RPC_DISPLAY_ADDR));
546 	rcu_read_unlock();
547 
548 	return 0;
549 }
550 EXPORT_SYMBOL_GPL(nfs_show_options);
551 
552 #if IS_ENABLED(CONFIG_NFS_V4)
553 static void show_lease(struct seq_file *m, struct nfs_server *server)
554 {
555 	struct nfs_client *clp = server->nfs_client;
556 	unsigned long expire;
557 
558 	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
559 	expire = clp->cl_last_renewal + clp->cl_lease_time;
560 	seq_printf(m, ",lease_expired=%ld",
561 		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
562 }
563 #ifdef CONFIG_NFS_V4_1
564 static void show_sessions(struct seq_file *m, struct nfs_server *server)
565 {
566 	if (nfs4_has_session(server->nfs_client))
567 		seq_puts(m, ",sessions");
568 }
569 #else
570 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
571 #endif
572 #endif
573 
574 #ifdef CONFIG_NFS_V4_1
575 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
576 {
577 	seq_printf(m, ",pnfs=");
578 	if (server->pnfs_curr_ld)
579 		seq_printf(m, "%s", server->pnfs_curr_ld->name);
580 	else
581 		seq_printf(m, "not configured");
582 }
583 
584 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
585 {
586 	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
587 		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
588 		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
589 			   "date='%llu,%u'",
590 			   impl_id->name, impl_id->domain,
591 			   impl_id->date.seconds, impl_id->date.nseconds);
592 	}
593 }
594 #else
595 #if IS_ENABLED(CONFIG_NFS_V4)
596 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
597 {
598 }
599 #endif
600 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
601 {
602 }
603 #endif
604 
605 int nfs_show_devname(struct seq_file *m, struct dentry *root)
606 {
607 	char *page = (char *) __get_free_page(GFP_KERNEL);
608 	char *devname, *dummy;
609 	int err = 0;
610 	if (!page)
611 		return -ENOMEM;
612 	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
613 	if (IS_ERR(devname))
614 		err = PTR_ERR(devname);
615 	else
616 		seq_escape(m, devname, " \t\n\\");
617 	free_page((unsigned long)page);
618 	return err;
619 }
620 EXPORT_SYMBOL_GPL(nfs_show_devname);
621 
622 int nfs_show_path(struct seq_file *m, struct dentry *dentry)
623 {
624 	seq_puts(m, "/");
625 	return 0;
626 }
627 EXPORT_SYMBOL_GPL(nfs_show_path);
628 
629 /*
630  * Present statistical information for this VFS mountpoint
631  */
632 int nfs_show_stats(struct seq_file *m, struct dentry *root)
633 {
634 	int i, cpu;
635 	struct nfs_server *nfss = NFS_SB(root->d_sb);
636 	struct rpc_auth *auth = nfss->client->cl_auth;
637 	struct nfs_iostats totals = { };
638 
639 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
640 
641 	/*
642 	 * Display all mount option settings
643 	 */
644 	seq_puts(m, "\n\topts:\t");
645 	seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
646 	seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
647 	seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
648 	seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
649 	nfs_show_mount_options(m, nfss, 1);
650 
651 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
652 
653 	show_implementation_id(m, nfss);
654 
655 	seq_puts(m, "\n\tcaps:\t");
656 	seq_printf(m, "caps=0x%x", nfss->caps);
657 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
658 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
659 	seq_printf(m, ",bsize=%u", nfss->bsize);
660 	seq_printf(m, ",namlen=%u", nfss->namelen);
661 
662 #if IS_ENABLED(CONFIG_NFS_V4)
663 	if (nfss->nfs_client->rpc_ops->version == 4) {
664 		seq_puts(m, "\n\tnfsv4:\t");
665 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
666 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
667 		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
668 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
669 		show_sessions(m, nfss);
670 		show_pnfs(m, nfss);
671 		show_lease(m, nfss);
672 	}
673 #endif
674 
675 	/*
676 	 * Display security flavor in effect for this mount
677 	 */
678 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
679 	if (auth->au_flavor)
680 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
681 
682 	/*
683 	 * Display superblock I/O counters
684 	 */
685 	for_each_possible_cpu(cpu) {
686 		struct nfs_iostats *stats;
687 
688 		preempt_disable();
689 		stats = per_cpu_ptr(nfss->io_stats, cpu);
690 
691 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
692 			totals.events[i] += stats->events[i];
693 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
694 			totals.bytes[i] += stats->bytes[i];
695 #ifdef CONFIG_NFS_FSCACHE
696 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
697 			totals.fscache[i] += stats->fscache[i];
698 #endif
699 
700 		preempt_enable();
701 	}
702 
703 	seq_puts(m, "\n\tevents:\t");
704 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
705 		seq_printf(m, "%lu ", totals.events[i]);
706 	seq_puts(m, "\n\tbytes:\t");
707 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
708 		seq_printf(m, "%Lu ", totals.bytes[i]);
709 #ifdef CONFIG_NFS_FSCACHE
710 	if (nfss->options & NFS_OPTION_FSCACHE) {
711 		seq_puts(m, "\n\tfsc:\t");
712 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
713 			seq_printf(m, "%Lu ", totals.fscache[i]);
714 	}
715 #endif
716 	seq_putc(m, '\n');
717 
718 	rpc_clnt_show_stats(m, nfss->client);
719 
720 	return 0;
721 }
722 EXPORT_SYMBOL_GPL(nfs_show_stats);
723 
724 /*
725  * Begin unmount by attempting to remove all automounted mountpoints we added
726  * in response to xdev traversals and referrals
727  */
728 void nfs_umount_begin(struct super_block *sb)
729 {
730 	struct nfs_server *server;
731 	struct rpc_clnt *rpc;
732 
733 	server = NFS_SB(sb);
734 	/* -EIO all pending I/O */
735 	rpc = server->client_acl;
736 	if (!IS_ERR(rpc))
737 		rpc_killall_tasks(rpc);
738 	rpc = server->client;
739 	if (!IS_ERR(rpc))
740 		rpc_killall_tasks(rpc);
741 }
742 EXPORT_SYMBOL_GPL(nfs_umount_begin);
743 
744 /*
745  * Return true if 'match' is in auth_info or auth_info is empty.
746  * Return false otherwise.
747  */
748 bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
749 			 rpc_authflavor_t match)
750 {
751 	int i;
752 
753 	if (!auth_info->flavor_len)
754 		return true;
755 
756 	for (i = 0; i < auth_info->flavor_len; i++) {
757 		if (auth_info->flavors[i] == match)
758 			return true;
759 	}
760 	return false;
761 }
762 EXPORT_SYMBOL_GPL(nfs_auth_info_match);
763 
764 /*
765  * Ensure that a specified authtype in ctx->auth_info is supported by
766  * the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
767  * -EACCES if not.
768  */
769 static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
770 				  rpc_authflavor_t *server_authlist,
771 				  unsigned int count)
772 {
773 	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
774 	bool found_auth_null = false;
775 	unsigned int i;
776 
777 	/*
778 	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
779 	 * must be in the list returned by the server.
780 	 *
781 	 * AUTH_NULL has a special meaning when it's in the server list - it
782 	 * means that the server will ignore the rpc creds, so any flavor
783 	 * can be used but still use the sec= that was specified.
784 	 *
785 	 * Note also that the MNT procedure in MNTv1 does not return a list
786 	 * of supported security flavors. In this case, nfs_mount() fabricates
787 	 * a security flavor list containing just AUTH_NULL.
788 	 */
789 	for (i = 0; i < count; i++) {
790 		flavor = server_authlist[i];
791 
792 		if (nfs_auth_info_match(&ctx->auth_info, flavor))
793 			goto out;
794 
795 		if (flavor == RPC_AUTH_NULL)
796 			found_auth_null = true;
797 	}
798 
799 	if (found_auth_null) {
800 		flavor = ctx->auth_info.flavors[0];
801 		goto out;
802 	}
803 
804 	dfprintk(MOUNT,
805 		 "NFS: specified auth flavors not supported by server\n");
806 	return -EACCES;
807 
808 out:
809 	ctx->selected_flavor = flavor;
810 	dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
811 	return 0;
812 }
813 
814 /*
815  * Use the remote server's MOUNT service to request the NFS file handle
816  * corresponding to the provided path.
817  */
818 static int nfs_request_mount(struct fs_context *fc,
819 			     struct nfs_fh *root_fh,
820 			     rpc_authflavor_t *server_authlist,
821 			     unsigned int *server_authlist_len)
822 {
823 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
824 	struct nfs_mount_request request = {
825 		.sap		= &ctx->mount_server._address,
826 		.dirpath	= ctx->nfs_server.export_path,
827 		.protocol	= ctx->mount_server.protocol,
828 		.fh		= root_fh,
829 		.noresvport	= ctx->flags & NFS_MOUNT_NORESVPORT,
830 		.auth_flav_len	= server_authlist_len,
831 		.auth_flavs	= server_authlist,
832 		.net		= fc->net_ns,
833 	};
834 	int status;
835 
836 	if (ctx->mount_server.version == 0) {
837 		switch (ctx->version) {
838 			default:
839 				ctx->mount_server.version = NFS_MNT3_VERSION;
840 				break;
841 			case 2:
842 				ctx->mount_server.version = NFS_MNT_VERSION;
843 		}
844 	}
845 	request.version = ctx->mount_server.version;
846 
847 	if (ctx->mount_server.hostname)
848 		request.hostname = ctx->mount_server.hostname;
849 	else
850 		request.hostname = ctx->nfs_server.hostname;
851 
852 	/*
853 	 * Construct the mount server's address.
854 	 */
855 	if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
856 		memcpy(request.sap, &ctx->nfs_server._address,
857 		       ctx->nfs_server.addrlen);
858 		ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
859 	}
860 	request.salen = ctx->mount_server.addrlen;
861 	nfs_set_port(request.sap, &ctx->mount_server.port, 0);
862 
863 	/*
864 	 * Now ask the mount server to map our export path
865 	 * to a file handle.
866 	 */
867 	status = nfs_mount(&request, ctx->timeo, ctx->retrans);
868 	if (status != 0) {
869 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
870 				request.hostname, status);
871 		return status;
872 	}
873 
874 	return 0;
875 }
876 
877 static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
878 {
879 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
880 	int status;
881 	unsigned int i;
882 	bool tried_auth_unix = false;
883 	bool auth_null_in_list = false;
884 	struct nfs_server *server = ERR_PTR(-EACCES);
885 	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
886 	unsigned int authlist_len = ARRAY_SIZE(authlist);
887 
888 	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
889 	if (status)
890 		return ERR_PTR(status);
891 
892 	/*
893 	 * Was a sec= authflavor specified in the options? First, verify
894 	 * whether the server supports it, and then just try to use it if so.
895 	 */
896 	if (ctx->auth_info.flavor_len > 0) {
897 		status = nfs_verify_authflavors(ctx, authlist, authlist_len);
898 		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
899 			 ctx->selected_flavor);
900 		if (status)
901 			return ERR_PTR(status);
902 		return ctx->nfs_mod->rpc_ops->create_server(fc);
903 	}
904 
905 	/*
906 	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
907 	 * SHOULD prefer the flavor listed first. However, some servers list
908 	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
909 	 */
910 	for (i = 0; i < authlist_len; ++i) {
911 		rpc_authflavor_t flavor;
912 		struct rpcsec_gss_info info;
913 
914 		flavor = authlist[i];
915 		switch (flavor) {
916 		case RPC_AUTH_UNIX:
917 			tried_auth_unix = true;
918 			break;
919 		case RPC_AUTH_NULL:
920 			auth_null_in_list = true;
921 			continue;
922 		default:
923 			if (rpcauth_get_gssinfo(flavor, &info) != 0)
924 				continue;
925 			break;
926 		}
927 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
928 		ctx->selected_flavor = flavor;
929 		server = ctx->nfs_mod->rpc_ops->create_server(fc);
930 		if (!IS_ERR(server))
931 			return server;
932 	}
933 
934 	/*
935 	 * Nothing we tried so far worked. At this point, give up if we've
936 	 * already tried AUTH_UNIX or if the server's list doesn't contain
937 	 * AUTH_NULL
938 	 */
939 	if (tried_auth_unix || !auth_null_in_list)
940 		return server;
941 
942 	/* Last chance! Try AUTH_UNIX */
943 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
944 	ctx->selected_flavor = RPC_AUTH_UNIX;
945 	return ctx->nfs_mod->rpc_ops->create_server(fc);
946 }
947 
948 int nfs_try_get_tree(struct fs_context *fc)
949 {
950 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
951 
952 	if (ctx->need_mount)
953 		ctx->server = nfs_try_mount_request(fc);
954 	else
955 		ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
956 
957 	return nfs_get_tree_common(fc);
958 }
959 EXPORT_SYMBOL_GPL(nfs_try_get_tree);
960 
961 
962 #define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
963 		| NFS_MOUNT_SECURE \
964 		| NFS_MOUNT_TCP \
965 		| NFS_MOUNT_VER3 \
966 		| NFS_MOUNT_KERBEROS \
967 		| NFS_MOUNT_NONLM \
968 		| NFS_MOUNT_BROKEN_SUID \
969 		| NFS_MOUNT_STRICTLOCK \
970 		| NFS_MOUNT_LEGACY_INTERFACE)
971 
972 #define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
973 		~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
974 
975 static int
976 nfs_compare_remount_data(struct nfs_server *nfss,
977 			 struct nfs_fs_context *ctx)
978 {
979 	if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
980 	    ctx->rsize != nfss->rsize ||
981 	    ctx->wsize != nfss->wsize ||
982 	    ctx->version != nfss->nfs_client->rpc_ops->version ||
983 	    ctx->minorversion != nfss->nfs_client->cl_minorversion ||
984 	    ctx->retrans != nfss->client->cl_timeout->to_retries ||
985 	    !nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
986 	    ctx->acregmin != nfss->acregmin / HZ ||
987 	    ctx->acregmax != nfss->acregmax / HZ ||
988 	    ctx->acdirmin != nfss->acdirmin / HZ ||
989 	    ctx->acdirmax != nfss->acdirmax / HZ ||
990 	    ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
991 	    (ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
992 	    ctx->nfs_server.port != nfss->port ||
993 	    ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
994 	    !rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
995 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
996 		return -EINVAL;
997 
998 	return 0;
999 }
1000 
1001 int nfs_reconfigure(struct fs_context *fc)
1002 {
1003 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1004 	struct super_block *sb = fc->root->d_sb;
1005 	struct nfs_server *nfss = sb->s_fs_info;
1006 	int ret;
1007 
1008 	sync_filesystem(sb);
1009 
1010 	/*
1011 	 * Userspace mount programs that send binary options generally send
1012 	 * them populated with default values. We have no way to know which
1013 	 * ones were explicitly specified. Fall back to legacy behavior and
1014 	 * just return success.
1015 	 */
1016 	if (ctx->skip_reconfig_option_check)
1017 		return 0;
1018 
1019 	/*
1020 	 * noac is a special case. It implies -o sync, but that's not
1021 	 * necessarily reflected in the mtab options. reconfigure_super
1022 	 * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
1023 	 * remount options, so we have to explicitly reset it.
1024 	 */
1025 	if (ctx->flags & NFS_MOUNT_NOAC) {
1026 		fc->sb_flags |= SB_SYNCHRONOUS;
1027 		fc->sb_flags_mask |= SB_SYNCHRONOUS;
1028 	}
1029 
1030 	/* compare new mount options with old ones */
1031 	ret = nfs_compare_remount_data(nfss, ctx);
1032 	if (ret)
1033 		return ret;
1034 
1035 	return nfs_probe_server(nfss, NFS_FH(d_inode(fc->root)));
1036 }
1037 EXPORT_SYMBOL_GPL(nfs_reconfigure);
1038 
1039 /*
1040  * Finish setting up an NFS superblock
1041  */
1042 static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
1043 {
1044 	struct nfs_server *server = NFS_SB(sb);
1045 
1046 	sb->s_blocksize_bits = 0;
1047 	sb->s_blocksize = 0;
1048 	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
1049 	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
1050 	if (ctx->bsize)
1051 		sb->s_blocksize = nfs_block_size(ctx->bsize, &sb->s_blocksize_bits);
1052 
1053 	switch (server->nfs_client->rpc_ops->version) {
1054 	case 2:
1055 		sb->s_time_gran = 1000;
1056 		sb->s_time_min = 0;
1057 		sb->s_time_max = U32_MAX;
1058 		break;
1059 	case 3:
1060 		/*
1061 		 * The VFS shouldn't apply the umask to mode bits.
1062 		 * We will do so ourselves when necessary.
1063 		 */
1064 		sb->s_flags |= SB_POSIXACL;
1065 		sb->s_time_gran = 1;
1066 		sb->s_time_min = 0;
1067 		sb->s_time_max = U32_MAX;
1068 		sb->s_export_op = &nfs_export_ops;
1069 		break;
1070 	case 4:
1071 		sb->s_flags |= SB_POSIXACL;
1072 		sb->s_time_gran = 1;
1073 		sb->s_time_min = S64_MIN;
1074 		sb->s_time_max = S64_MAX;
1075 		if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
1076 			sb->s_export_op = &nfs_export_ops;
1077 		break;
1078 	}
1079 
1080 	sb->s_magic = NFS_SUPER_MAGIC;
1081 
1082 	/* We probably want something more informative here */
1083 	snprintf(sb->s_id, sizeof(sb->s_id),
1084 		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1085 
1086 	if (sb->s_blocksize == 0)
1087 		sb->s_blocksize = nfs_block_bits(server->wsize,
1088 						 &sb->s_blocksize_bits);
1089 
1090 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1091 	server->has_sec_mnt_opts = ctx->has_sec_mnt_opts;
1092 }
1093 
1094 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b,
1095 				     const struct fs_context *fc)
1096 {
1097 	const struct nfs_server *a = s->s_fs_info;
1098 	const struct rpc_clnt *clnt_a = a->client;
1099 	const struct rpc_clnt *clnt_b = b->client;
1100 
1101 	if ((s->s_flags & NFS_SB_MASK) != (fc->sb_flags & NFS_SB_MASK))
1102 		goto Ebusy;
1103 	if (a->nfs_client != b->nfs_client)
1104 		goto Ebusy;
1105 	if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
1106 		goto Ebusy;
1107 	if (a->wsize != b->wsize)
1108 		goto Ebusy;
1109 	if (a->rsize != b->rsize)
1110 		goto Ebusy;
1111 	if (a->acregmin != b->acregmin)
1112 		goto Ebusy;
1113 	if (a->acregmax != b->acregmax)
1114 		goto Ebusy;
1115 	if (a->acdirmin != b->acdirmin)
1116 		goto Ebusy;
1117 	if (a->acdirmax != b->acdirmax)
1118 		goto Ebusy;
1119 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1120 		goto Ebusy;
1121 	return 1;
1122 Ebusy:
1123 	return 0;
1124 }
1125 
1126 static int nfs_set_super(struct super_block *s, struct fs_context *fc)
1127 {
1128 	struct nfs_server *server = fc->s_fs_info;
1129 	int ret;
1130 
1131 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
1132 	ret = set_anon_super(s, server);
1133 	if (ret == 0)
1134 		server->s_dev = s->s_dev;
1135 	return ret;
1136 }
1137 
1138 static int nfs_compare_super_address(struct nfs_server *server1,
1139 				     struct nfs_server *server2)
1140 {
1141 	struct sockaddr *sap1, *sap2;
1142 	struct rpc_xprt *xprt1 = server1->client->cl_xprt;
1143 	struct rpc_xprt *xprt2 = server2->client->cl_xprt;
1144 
1145 	if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
1146 		return 0;
1147 
1148 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1149 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1150 
1151 	if (sap1->sa_family != sap2->sa_family)
1152 		return 0;
1153 
1154 	switch (sap1->sa_family) {
1155 	case AF_INET: {
1156 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1157 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1158 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1159 			return 0;
1160 		if (sin1->sin_port != sin2->sin_port)
1161 			return 0;
1162 		break;
1163 	}
1164 	case AF_INET6: {
1165 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1166 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1167 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1168 			return 0;
1169 		if (sin1->sin6_port != sin2->sin6_port)
1170 			return 0;
1171 		break;
1172 	}
1173 	default:
1174 		return 0;
1175 	}
1176 
1177 	return 1;
1178 }
1179 
1180 static int nfs_compare_userns(const struct nfs_server *old,
1181 		const struct nfs_server *new)
1182 {
1183 	const struct user_namespace *oldns = &init_user_ns;
1184 	const struct user_namespace *newns = &init_user_ns;
1185 
1186 	if (old->client && old->client->cl_cred)
1187 		oldns = old->client->cl_cred->user_ns;
1188 	if (new->client && new->client->cl_cred)
1189 		newns = new->client->cl_cred->user_ns;
1190 	if (oldns != newns)
1191 		return 0;
1192 	return 1;
1193 }
1194 
1195 static int nfs_compare_super(struct super_block *sb, struct fs_context *fc)
1196 {
1197 	struct nfs_server *server = fc->s_fs_info, *old = NFS_SB(sb);
1198 
1199 	if (!nfs_compare_super_address(old, server))
1200 		return 0;
1201 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1202 	if (old->flags & NFS_MOUNT_UNSHARED)
1203 		return 0;
1204 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1205 		return 0;
1206 	if (!nfs_compare_userns(old, server))
1207 		return 0;
1208 	if ((old->has_sec_mnt_opts || fc->security) &&
1209 			security_sb_mnt_opts_compat(sb, fc->security))
1210 		return 0;
1211 	return nfs_compare_mount_options(sb, server, fc);
1212 }
1213 
1214 #ifdef CONFIG_NFS_FSCACHE
1215 static int nfs_get_cache_cookie(struct super_block *sb,
1216 				struct nfs_fs_context *ctx)
1217 {
1218 	struct nfs_server *nfss = NFS_SB(sb);
1219 	char *uniq = NULL;
1220 	int ulen = 0;
1221 
1222 	nfss->fscache = NULL;
1223 
1224 	if (!ctx)
1225 		return 0;
1226 
1227 	if (ctx->clone_data.sb) {
1228 		struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
1229 		if (!(mnt_s->options & NFS_OPTION_FSCACHE))
1230 			return 0;
1231 		if (mnt_s->fscache_uniq) {
1232 			uniq = mnt_s->fscache_uniq;
1233 			ulen = strlen(uniq);
1234 		}
1235 	} else {
1236 		if (!(ctx->options & NFS_OPTION_FSCACHE))
1237 			return 0;
1238 		if (ctx->fscache_uniq) {
1239 			uniq = ctx->fscache_uniq;
1240 			ulen = strlen(ctx->fscache_uniq);
1241 		}
1242 	}
1243 
1244 	return nfs_fscache_get_super_cookie(sb, uniq, ulen);
1245 }
1246 #else
1247 static int nfs_get_cache_cookie(struct super_block *sb,
1248 				struct nfs_fs_context *ctx)
1249 {
1250 	return 0;
1251 }
1252 #endif
1253 
1254 int nfs_get_tree_common(struct fs_context *fc)
1255 {
1256 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1257 	struct super_block *s;
1258 	int (*compare_super)(struct super_block *, struct fs_context *) = nfs_compare_super;
1259 	struct nfs_server *server = ctx->server;
1260 	int error;
1261 
1262 	ctx->server = NULL;
1263 	if (IS_ERR(server))
1264 		return PTR_ERR(server);
1265 
1266 	if (server->flags & NFS_MOUNT_UNSHARED)
1267 		compare_super = NULL;
1268 
1269 	/* -o noac implies -o sync */
1270 	if (server->flags & NFS_MOUNT_NOAC)
1271 		fc->sb_flags |= SB_SYNCHRONOUS;
1272 
1273 	if (ctx->clone_data.sb)
1274 		if (ctx->clone_data.sb->s_flags & SB_SYNCHRONOUS)
1275 			fc->sb_flags |= SB_SYNCHRONOUS;
1276 
1277 	if (server->caps & NFS_CAP_SECURITY_LABEL)
1278 		fc->lsm_flags |= SECURITY_LSM_NATIVE_LABELS;
1279 
1280 	/* Get a superblock - note that we may end up sharing one that already exists */
1281 	fc->s_fs_info = server;
1282 	s = sget_fc(fc, compare_super, nfs_set_super);
1283 	fc->s_fs_info = NULL;
1284 	if (IS_ERR(s)) {
1285 		error = PTR_ERR(s);
1286 		nfs_errorf(fc, "NFS: Couldn't get superblock");
1287 		goto out_err_nosb;
1288 	}
1289 
1290 	if (s->s_fs_info != server) {
1291 		nfs_free_server(server);
1292 		server = NULL;
1293 	} else {
1294 		error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
1295 					     MINOR(server->s_dev));
1296 		if (error)
1297 			goto error_splat_super;
1298 		s->s_bdi->io_pages = server->rpages;
1299 		server->super = s;
1300 	}
1301 
1302 	if (!s->s_root) {
1303 		unsigned bsize = ctx->clone_data.inherited_bsize;
1304 		/* initial superblock/root creation */
1305 		nfs_fill_super(s, ctx);
1306 		if (bsize) {
1307 			s->s_blocksize_bits = bsize;
1308 			s->s_blocksize = 1U << bsize;
1309 		}
1310 		error = nfs_get_cache_cookie(s, ctx);
1311 		if (error < 0)
1312 			goto error_splat_super;
1313 	}
1314 
1315 	error = nfs_get_root(s, fc);
1316 	if (error < 0) {
1317 		nfs_errorf(fc, "NFS: Couldn't get root dentry");
1318 		goto error_splat_super;
1319 	}
1320 
1321 	s->s_flags |= SB_ACTIVE;
1322 	error = 0;
1323 
1324 out:
1325 	return error;
1326 
1327 out_err_nosb:
1328 	nfs_free_server(server);
1329 	goto out;
1330 error_splat_super:
1331 	deactivate_locked_super(s);
1332 	goto out;
1333 }
1334 
1335 /*
1336  * Destroy an NFS2/3 superblock
1337  */
1338 void nfs_kill_super(struct super_block *s)
1339 {
1340 	struct nfs_server *server = NFS_SB(s);
1341 	dev_t dev = s->s_dev;
1342 
1343 	generic_shutdown_super(s);
1344 
1345 	nfs_fscache_release_super_cookie(s);
1346 
1347 	nfs_free_server(server);
1348 	free_anon_bdev(dev);
1349 }
1350 EXPORT_SYMBOL_GPL(nfs_kill_super);
1351 
1352 #if IS_ENABLED(CONFIG_NFS_V4)
1353 
1354 /*
1355  * NFS v4 module parameters need to stay in the
1356  * NFS client for backwards compatibility
1357  */
1358 unsigned int nfs_callback_set_tcpport;
1359 unsigned short nfs_callback_nr_threads;
1360 /* Default cache timeout is 10 minutes */
1361 unsigned int nfs_idmap_cache_timeout = 600;
1362 /* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
1363 bool nfs4_disable_idmapping = true;
1364 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
1365 unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
1366 unsigned short send_implementation_id = 1;
1367 char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
1368 bool recover_lost_locks = false;
1369 
1370 EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
1371 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
1372 EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
1373 EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
1374 EXPORT_SYMBOL_GPL(max_session_slots);
1375 EXPORT_SYMBOL_GPL(max_session_cb_slots);
1376 EXPORT_SYMBOL_GPL(send_implementation_id);
1377 EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
1378 EXPORT_SYMBOL_GPL(recover_lost_locks);
1379 
1380 #define NFS_CALLBACK_MAXPORTNR (65535U)
1381 
1382 static int param_set_portnr(const char *val, const struct kernel_param *kp)
1383 {
1384 	unsigned long num;
1385 	int ret;
1386 
1387 	if (!val)
1388 		return -EINVAL;
1389 	ret = kstrtoul(val, 0, &num);
1390 	if (ret || num > NFS_CALLBACK_MAXPORTNR)
1391 		return -EINVAL;
1392 	*((unsigned int *)kp->arg) = num;
1393 	return 0;
1394 }
1395 static const struct kernel_param_ops param_ops_portnr = {
1396 	.set = param_set_portnr,
1397 	.get = param_get_uint,
1398 };
1399 #define param_check_portnr(name, p) __param_check(name, p, unsigned int)
1400 
1401 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1402 module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
1403 MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
1404 		"assigned to the NFSv4 callback channels.");
1405 module_param(nfs_idmap_cache_timeout, int, 0644);
1406 module_param(nfs4_disable_idmapping, bool, 0644);
1407 module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
1408 			NFS4_CLIENT_ID_UNIQ_LEN, 0600);
1409 MODULE_PARM_DESC(nfs4_disable_idmapping,
1410 		"Turn off NFSv4 idmapping when using 'sec=sys'");
1411 module_param(max_session_slots, ushort, 0644);
1412 MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
1413 		"requests the client will negotiate");
1414 module_param(max_session_cb_slots, ushort, 0644);
1415 MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
1416 		"callbacks the client will process for a given server");
1417 module_param(send_implementation_id, ushort, 0644);
1418 MODULE_PARM_DESC(send_implementation_id,
1419 		"Send implementation ID with NFSv4.1 exchange_id");
1420 MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
1421 
1422 module_param(recover_lost_locks, bool, 0644);
1423 MODULE_PARM_DESC(recover_lost_locks,
1424 		 "If the server reports that a lock might be lost, "
1425 		 "try to recover it risking data corruption.");
1426 
1427 
1428 #endif /* CONFIG_NFS_V4 */
1429