xref: /openbmc/linux/fs/nfs/super.c (revision 94588c1b)
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);
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 (nfss->port != NFS_PORT)
484 			seq_printf(m, ",port=%u", nfss->port);
485 	} else
486 		if (nfss->port)
487 			seq_printf(m, ",port=%u", nfss->port);
488 
489 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
490 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
491 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
492 
493 	if (version != 4)
494 		nfs_show_mountd_options(m, nfss, showdefaults);
495 	else
496 		nfs_show_nfsv4_options(m, nfss, showdefaults);
497 
498 	if (nfss->options & NFS_OPTION_FSCACHE)
499 		seq_puts(m, ",fsc");
500 
501 	if (nfss->options & NFS_OPTION_MIGRATION)
502 		seq_puts(m, ",migration");
503 
504 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
505 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
506 			seq_puts(m, ",lookupcache=none");
507 		else
508 			seq_puts(m, ",lookupcache=pos");
509 	}
510 
511 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
512 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
513 
514 	if (!local_flock && !local_fcntl)
515 		seq_puts(m, ",local_lock=none");
516 	else if (local_flock && local_fcntl)
517 		seq_puts(m, ",local_lock=all");
518 	else if (local_flock)
519 		seq_puts(m, ",local_lock=flock");
520 	else
521 		seq_puts(m, ",local_lock=posix");
522 
523 	if (nfss->flags & NFS_MOUNT_WRITE_EAGER) {
524 		if (nfss->flags & NFS_MOUNT_WRITE_WAIT)
525 			seq_puts(m, ",write=wait");
526 		else
527 			seq_puts(m, ",write=eager");
528 	}
529 }
530 
531 /*
532  * Describe the mount options on this VFS mountpoint
533  */
534 int nfs_show_options(struct seq_file *m, struct dentry *root)
535 {
536 	struct nfs_server *nfss = NFS_SB(root->d_sb);
537 
538 	nfs_show_mount_options(m, nfss, 0);
539 
540 	rcu_read_lock();
541 	seq_printf(m, ",addr=%s",
542 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
543 							RPC_DISPLAY_ADDR));
544 	rcu_read_unlock();
545 
546 	return 0;
547 }
548 EXPORT_SYMBOL_GPL(nfs_show_options);
549 
550 #if IS_ENABLED(CONFIG_NFS_V4)
551 static void show_lease(struct seq_file *m, struct nfs_server *server)
552 {
553 	struct nfs_client *clp = server->nfs_client;
554 	unsigned long expire;
555 
556 	seq_printf(m, ",lease_time=%ld", clp->cl_lease_time / HZ);
557 	expire = clp->cl_last_renewal + clp->cl_lease_time;
558 	seq_printf(m, ",lease_expired=%ld",
559 		   time_after(expire, jiffies) ?  0 : (jiffies - expire) / HZ);
560 }
561 #ifdef CONFIG_NFS_V4_1
562 static void show_sessions(struct seq_file *m, struct nfs_server *server)
563 {
564 	if (nfs4_has_session(server->nfs_client))
565 		seq_puts(m, ",sessions");
566 }
567 #else
568 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
569 #endif
570 #endif
571 
572 #ifdef CONFIG_NFS_V4_1
573 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
574 {
575 	seq_printf(m, ",pnfs=");
576 	if (server->pnfs_curr_ld)
577 		seq_printf(m, "%s", server->pnfs_curr_ld->name);
578 	else
579 		seq_printf(m, "not configured");
580 }
581 
582 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
583 {
584 	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
585 		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
586 		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
587 			   "date='%llu,%u'",
588 			   impl_id->name, impl_id->domain,
589 			   impl_id->date.seconds, impl_id->date.nseconds);
590 	}
591 }
592 #else
593 #if IS_ENABLED(CONFIG_NFS_V4)
594 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
595 {
596 }
597 #endif
598 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
599 {
600 }
601 #endif
602 
603 int nfs_show_devname(struct seq_file *m, struct dentry *root)
604 {
605 	char *page = (char *) __get_free_page(GFP_KERNEL);
606 	char *devname, *dummy;
607 	int err = 0;
608 	if (!page)
609 		return -ENOMEM;
610 	devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
611 	if (IS_ERR(devname))
612 		err = PTR_ERR(devname);
613 	else
614 		seq_escape(m, devname, " \t\n\\");
615 	free_page((unsigned long)page);
616 	return err;
617 }
618 EXPORT_SYMBOL_GPL(nfs_show_devname);
619 
620 int nfs_show_path(struct seq_file *m, struct dentry *dentry)
621 {
622 	seq_puts(m, "/");
623 	return 0;
624 }
625 EXPORT_SYMBOL_GPL(nfs_show_path);
626 
627 /*
628  * Present statistical information for this VFS mountpoint
629  */
630 int nfs_show_stats(struct seq_file *m, struct dentry *root)
631 {
632 	int i, cpu;
633 	struct nfs_server *nfss = NFS_SB(root->d_sb);
634 	struct rpc_auth *auth = nfss->client->cl_auth;
635 	struct nfs_iostats totals = { };
636 
637 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
638 
639 	/*
640 	 * Display all mount option settings
641 	 */
642 	seq_puts(m, "\n\topts:\t");
643 	seq_puts(m, sb_rdonly(root->d_sb) ? "ro" : "rw");
644 	seq_puts(m, root->d_sb->s_flags & SB_SYNCHRONOUS ? ",sync" : "");
645 	seq_puts(m, root->d_sb->s_flags & SB_NOATIME ? ",noatime" : "");
646 	seq_puts(m, root->d_sb->s_flags & SB_NODIRATIME ? ",nodiratime" : "");
647 	nfs_show_mount_options(m, nfss, 1);
648 
649 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
650 
651 	show_implementation_id(m, nfss);
652 
653 	seq_puts(m, "\n\tcaps:\t");
654 	seq_printf(m, "caps=0x%x", nfss->caps);
655 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
656 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
657 	seq_printf(m, ",bsize=%u", nfss->bsize);
658 	seq_printf(m, ",namlen=%u", nfss->namelen);
659 
660 #if IS_ENABLED(CONFIG_NFS_V4)
661 	if (nfss->nfs_client->rpc_ops->version == 4) {
662 		seq_puts(m, "\n\tnfsv4:\t");
663 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
664 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
665 		seq_printf(m, ",bm2=0x%x", nfss->attr_bitmask[2]);
666 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
667 		show_sessions(m, nfss);
668 		show_pnfs(m, nfss);
669 		show_lease(m, nfss);
670 	}
671 #endif
672 
673 	/*
674 	 * Display security flavor in effect for this mount
675 	 */
676 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
677 	if (auth->au_flavor)
678 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
679 
680 	/*
681 	 * Display superblock I/O counters
682 	 */
683 	for_each_possible_cpu(cpu) {
684 		struct nfs_iostats *stats;
685 
686 		preempt_disable();
687 		stats = per_cpu_ptr(nfss->io_stats, cpu);
688 
689 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
690 			totals.events[i] += stats->events[i];
691 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
692 			totals.bytes[i] += stats->bytes[i];
693 #ifdef CONFIG_NFS_FSCACHE
694 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
695 			totals.fscache[i] += stats->fscache[i];
696 #endif
697 
698 		preempt_enable();
699 	}
700 
701 	seq_puts(m, "\n\tevents:\t");
702 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
703 		seq_printf(m, "%lu ", totals.events[i]);
704 	seq_puts(m, "\n\tbytes:\t");
705 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
706 		seq_printf(m, "%Lu ", totals.bytes[i]);
707 #ifdef CONFIG_NFS_FSCACHE
708 	if (nfss->options & NFS_OPTION_FSCACHE) {
709 		seq_puts(m, "\n\tfsc:\t");
710 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
711 			seq_printf(m, "%Lu ", totals.fscache[i]);
712 	}
713 #endif
714 	seq_putc(m, '\n');
715 
716 	rpc_clnt_show_stats(m, nfss->client);
717 
718 	return 0;
719 }
720 EXPORT_SYMBOL_GPL(nfs_show_stats);
721 
722 /*
723  * Begin unmount by attempting to remove all automounted mountpoints we added
724  * in response to xdev traversals and referrals
725  */
726 void nfs_umount_begin(struct super_block *sb)
727 {
728 	struct nfs_server *server;
729 	struct rpc_clnt *rpc;
730 
731 	server = NFS_SB(sb);
732 	/* -EIO all pending I/O */
733 	rpc = server->client_acl;
734 	if (!IS_ERR(rpc))
735 		rpc_killall_tasks(rpc);
736 	rpc = server->client;
737 	if (!IS_ERR(rpc))
738 		rpc_killall_tasks(rpc);
739 }
740 EXPORT_SYMBOL_GPL(nfs_umount_begin);
741 
742 /*
743  * Return true if 'match' is in auth_info or auth_info is empty.
744  * Return false otherwise.
745  */
746 bool nfs_auth_info_match(const struct nfs_auth_info *auth_info,
747 			 rpc_authflavor_t match)
748 {
749 	int i;
750 
751 	if (!auth_info->flavor_len)
752 		return true;
753 
754 	for (i = 0; i < auth_info->flavor_len; i++) {
755 		if (auth_info->flavors[i] == match)
756 			return true;
757 	}
758 	return false;
759 }
760 EXPORT_SYMBOL_GPL(nfs_auth_info_match);
761 
762 /*
763  * Ensure that a specified authtype in ctx->auth_info is supported by
764  * the server. Returns 0 and sets ctx->selected_flavor if it's ok, and
765  * -EACCES if not.
766  */
767 static int nfs_verify_authflavors(struct nfs_fs_context *ctx,
768 				  rpc_authflavor_t *server_authlist,
769 				  unsigned int count)
770 {
771 	rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
772 	bool found_auth_null = false;
773 	unsigned int i;
774 
775 	/*
776 	 * If the sec= mount option is used, the specified flavor or AUTH_NULL
777 	 * must be in the list returned by the server.
778 	 *
779 	 * AUTH_NULL has a special meaning when it's in the server list - it
780 	 * means that the server will ignore the rpc creds, so any flavor
781 	 * can be used but still use the sec= that was specified.
782 	 *
783 	 * Note also that the MNT procedure in MNTv1 does not return a list
784 	 * of supported security flavors. In this case, nfs_mount() fabricates
785 	 * a security flavor list containing just AUTH_NULL.
786 	 */
787 	for (i = 0; i < count; i++) {
788 		flavor = server_authlist[i];
789 
790 		if (nfs_auth_info_match(&ctx->auth_info, flavor))
791 			goto out;
792 
793 		if (flavor == RPC_AUTH_NULL)
794 			found_auth_null = true;
795 	}
796 
797 	if (found_auth_null) {
798 		flavor = ctx->auth_info.flavors[0];
799 		goto out;
800 	}
801 
802 	dfprintk(MOUNT,
803 		 "NFS: specified auth flavors not supported by server\n");
804 	return -EACCES;
805 
806 out:
807 	ctx->selected_flavor = flavor;
808 	dfprintk(MOUNT, "NFS: using auth flavor %u\n", ctx->selected_flavor);
809 	return 0;
810 }
811 
812 /*
813  * Use the remote server's MOUNT service to request the NFS file handle
814  * corresponding to the provided path.
815  */
816 static int nfs_request_mount(struct fs_context *fc,
817 			     struct nfs_fh *root_fh,
818 			     rpc_authflavor_t *server_authlist,
819 			     unsigned int *server_authlist_len)
820 {
821 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
822 	struct nfs_mount_request request = {
823 		.sap		= (struct sockaddr *)
824 						&ctx->mount_server.address,
825 		.dirpath	= ctx->nfs_server.export_path,
826 		.protocol	= ctx->mount_server.protocol,
827 		.fh		= root_fh,
828 		.noresvport	= ctx->flags & NFS_MOUNT_NORESVPORT,
829 		.auth_flav_len	= server_authlist_len,
830 		.auth_flavs	= server_authlist,
831 		.net		= fc->net_ns,
832 	};
833 	int status;
834 
835 	if (ctx->mount_server.version == 0) {
836 		switch (ctx->version) {
837 			default:
838 				ctx->mount_server.version = NFS_MNT3_VERSION;
839 				break;
840 			case 2:
841 				ctx->mount_server.version = NFS_MNT_VERSION;
842 		}
843 	}
844 	request.version = ctx->mount_server.version;
845 
846 	if (ctx->mount_server.hostname)
847 		request.hostname = ctx->mount_server.hostname;
848 	else
849 		request.hostname = ctx->nfs_server.hostname;
850 
851 	/*
852 	 * Construct the mount server's address.
853 	 */
854 	if (ctx->mount_server.address.sa_family == AF_UNSPEC) {
855 		memcpy(request.sap, &ctx->nfs_server.address,
856 		       ctx->nfs_server.addrlen);
857 		ctx->mount_server.addrlen = ctx->nfs_server.addrlen;
858 	}
859 	request.salen = ctx->mount_server.addrlen;
860 	nfs_set_port(request.sap, &ctx->mount_server.port, 0);
861 
862 	/*
863 	 * Now ask the mount server to map our export path
864 	 * to a file handle.
865 	 */
866 	status = nfs_mount(&request, ctx->timeo, ctx->retrans);
867 	if (status != 0) {
868 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
869 				request.hostname, status);
870 		return status;
871 	}
872 
873 	return 0;
874 }
875 
876 static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
877 {
878 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
879 	int status;
880 	unsigned int i;
881 	bool tried_auth_unix = false;
882 	bool auth_null_in_list = false;
883 	struct nfs_server *server = ERR_PTR(-EACCES);
884 	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
885 	unsigned int authlist_len = ARRAY_SIZE(authlist);
886 
887 	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
888 	if (status)
889 		return ERR_PTR(status);
890 
891 	/*
892 	 * Was a sec= authflavor specified in the options? First, verify
893 	 * whether the server supports it, and then just try to use it if so.
894 	 */
895 	if (ctx->auth_info.flavor_len > 0) {
896 		status = nfs_verify_authflavors(ctx, authlist, authlist_len);
897 		dfprintk(MOUNT, "NFS: using auth flavor %u\n",
898 			 ctx->selected_flavor);
899 		if (status)
900 			return ERR_PTR(status);
901 		return ctx->nfs_mod->rpc_ops->create_server(fc);
902 	}
903 
904 	/*
905 	 * No sec= option was provided. RFC 2623, section 2.7 suggests we
906 	 * SHOULD prefer the flavor listed first. However, some servers list
907 	 * AUTH_NULL first. Avoid ever choosing AUTH_NULL.
908 	 */
909 	for (i = 0; i < authlist_len; ++i) {
910 		rpc_authflavor_t flavor;
911 		struct rpcsec_gss_info info;
912 
913 		flavor = authlist[i];
914 		switch (flavor) {
915 		case RPC_AUTH_UNIX:
916 			tried_auth_unix = true;
917 			break;
918 		case RPC_AUTH_NULL:
919 			auth_null_in_list = true;
920 			continue;
921 		default:
922 			if (rpcauth_get_gssinfo(flavor, &info) != 0)
923 				continue;
924 			break;
925 		}
926 		dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
927 		ctx->selected_flavor = flavor;
928 		server = ctx->nfs_mod->rpc_ops->create_server(fc);
929 		if (!IS_ERR(server))
930 			return server;
931 	}
932 
933 	/*
934 	 * Nothing we tried so far worked. At this point, give up if we've
935 	 * already tried AUTH_UNIX or if the server's list doesn't contain
936 	 * AUTH_NULL
937 	 */
938 	if (tried_auth_unix || !auth_null_in_list)
939 		return server;
940 
941 	/* Last chance! Try AUTH_UNIX */
942 	dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", RPC_AUTH_UNIX);
943 	ctx->selected_flavor = RPC_AUTH_UNIX;
944 	return ctx->nfs_mod->rpc_ops->create_server(fc);
945 }
946 
947 int nfs_try_get_tree(struct fs_context *fc)
948 {
949 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
950 
951 	if (ctx->need_mount)
952 		ctx->server = nfs_try_mount_request(fc);
953 	else
954 		ctx->server = ctx->nfs_mod->rpc_ops->create_server(fc);
955 
956 	return nfs_get_tree_common(fc);
957 }
958 EXPORT_SYMBOL_GPL(nfs_try_get_tree);
959 
960 
961 #define NFS_REMOUNT_CMP_FLAGMASK ~(NFS_MOUNT_INTR \
962 		| NFS_MOUNT_SECURE \
963 		| NFS_MOUNT_TCP \
964 		| NFS_MOUNT_VER3 \
965 		| NFS_MOUNT_KERBEROS \
966 		| NFS_MOUNT_NONLM \
967 		| NFS_MOUNT_BROKEN_SUID \
968 		| NFS_MOUNT_STRICTLOCK \
969 		| NFS_MOUNT_LEGACY_INTERFACE)
970 
971 #define NFS_MOUNT_CMP_FLAGMASK (NFS_REMOUNT_CMP_FLAGMASK & \
972 		~(NFS_MOUNT_UNSHARED | NFS_MOUNT_NORESVPORT))
973 
974 static int
975 nfs_compare_remount_data(struct nfs_server *nfss,
976 			 struct nfs_fs_context *ctx)
977 {
978 	if ((ctx->flags ^ nfss->flags) & NFS_REMOUNT_CMP_FLAGMASK ||
979 	    ctx->rsize != nfss->rsize ||
980 	    ctx->wsize != nfss->wsize ||
981 	    ctx->version != nfss->nfs_client->rpc_ops->version ||
982 	    ctx->minorversion != nfss->nfs_client->cl_minorversion ||
983 	    ctx->retrans != nfss->client->cl_timeout->to_retries ||
984 	    !nfs_auth_info_match(&ctx->auth_info, nfss->client->cl_auth->au_flavor) ||
985 	    ctx->acregmin != nfss->acregmin / HZ ||
986 	    ctx->acregmax != nfss->acregmax / HZ ||
987 	    ctx->acdirmin != nfss->acdirmin / HZ ||
988 	    ctx->acdirmax != nfss->acdirmax / HZ ||
989 	    ctx->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
990 	    (ctx->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
991 	    ctx->nfs_server.port != nfss->port ||
992 	    ctx->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
993 	    !rpc_cmp_addr((struct sockaddr *)&ctx->nfs_server.address,
994 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
995 		return -EINVAL;
996 
997 	return 0;
998 }
999 
1000 int nfs_reconfigure(struct fs_context *fc)
1001 {
1002 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1003 	struct super_block *sb = fc->root->d_sb;
1004 	struct nfs_server *nfss = sb->s_fs_info;
1005 
1006 	sync_filesystem(sb);
1007 
1008 	/*
1009 	 * Userspace mount programs that send binary options generally send
1010 	 * them populated with default values. We have no way to know which
1011 	 * ones were explicitly specified. Fall back to legacy behavior and
1012 	 * just return success.
1013 	 */
1014 	if (ctx->skip_reconfig_option_check)
1015 		return 0;
1016 
1017 	/*
1018 	 * noac is a special case. It implies -o sync, but that's not
1019 	 * necessarily reflected in the mtab options. reconfigure_super
1020 	 * will clear SB_SYNCHRONOUS if -o sync wasn't specified in the
1021 	 * remount options, so we have to explicitly reset it.
1022 	 */
1023 	if (ctx->flags & NFS_MOUNT_NOAC) {
1024 		fc->sb_flags |= SB_SYNCHRONOUS;
1025 		fc->sb_flags_mask |= SB_SYNCHRONOUS;
1026 	}
1027 
1028 	/* compare new mount options with old ones */
1029 	return nfs_compare_remount_data(nfss, ctx);
1030 }
1031 EXPORT_SYMBOL_GPL(nfs_reconfigure);
1032 
1033 /*
1034  * Finish setting up an NFS superblock
1035  */
1036 static void nfs_fill_super(struct super_block *sb, struct nfs_fs_context *ctx)
1037 {
1038 	struct nfs_server *server = NFS_SB(sb);
1039 
1040 	sb->s_blocksize_bits = 0;
1041 	sb->s_blocksize = 0;
1042 	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
1043 	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
1044 	if (ctx->bsize)
1045 		sb->s_blocksize = nfs_block_size(ctx->bsize, &sb->s_blocksize_bits);
1046 
1047 	if (server->nfs_client->rpc_ops->version != 2) {
1048 		/* The VFS shouldn't apply the umask to mode bits. We will do
1049 		 * so ourselves when necessary.
1050 		 */
1051 		sb->s_flags |= SB_POSIXACL;
1052 		sb->s_time_gran = 1;
1053 		sb->s_export_op = &nfs_export_ops;
1054 	} else
1055 		sb->s_time_gran = 1000;
1056 
1057 	if (server->nfs_client->rpc_ops->version != 4) {
1058 		sb->s_time_min = 0;
1059 		sb->s_time_max = U32_MAX;
1060 	} else {
1061 		sb->s_time_min = S64_MIN;
1062 		sb->s_time_max = S64_MAX;
1063 	}
1064 
1065 	sb->s_magic = NFS_SUPER_MAGIC;
1066 
1067 	/* We probably want something more informative here */
1068 	snprintf(sb->s_id, sizeof(sb->s_id),
1069 		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1070 
1071 	if (sb->s_blocksize == 0)
1072 		sb->s_blocksize = nfs_block_bits(server->wsize,
1073 						 &sb->s_blocksize_bits);
1074 
1075 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1076 	server->has_sec_mnt_opts = ctx->has_sec_mnt_opts;
1077 }
1078 
1079 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b,
1080 				     const struct fs_context *fc)
1081 {
1082 	const struct nfs_server *a = s->s_fs_info;
1083 	const struct rpc_clnt *clnt_a = a->client;
1084 	const struct rpc_clnt *clnt_b = b->client;
1085 
1086 	if ((s->s_flags & NFS_SB_MASK) != (fc->sb_flags & NFS_SB_MASK))
1087 		goto Ebusy;
1088 	if (a->nfs_client != b->nfs_client)
1089 		goto Ebusy;
1090 	if ((a->flags ^ b->flags) & NFS_MOUNT_CMP_FLAGMASK)
1091 		goto Ebusy;
1092 	if (a->wsize != b->wsize)
1093 		goto Ebusy;
1094 	if (a->rsize != b->rsize)
1095 		goto Ebusy;
1096 	if (a->acregmin != b->acregmin)
1097 		goto Ebusy;
1098 	if (a->acregmax != b->acregmax)
1099 		goto Ebusy;
1100 	if (a->acdirmin != b->acdirmin)
1101 		goto Ebusy;
1102 	if (a->acdirmax != b->acdirmax)
1103 		goto Ebusy;
1104 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1105 		goto Ebusy;
1106 	return 1;
1107 Ebusy:
1108 	return 0;
1109 }
1110 
1111 static int nfs_set_super(struct super_block *s, struct fs_context *fc)
1112 {
1113 	struct nfs_server *server = fc->s_fs_info;
1114 	int ret;
1115 
1116 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
1117 	ret = set_anon_super(s, server);
1118 	if (ret == 0)
1119 		server->s_dev = s->s_dev;
1120 	return ret;
1121 }
1122 
1123 static int nfs_compare_super_address(struct nfs_server *server1,
1124 				     struct nfs_server *server2)
1125 {
1126 	struct sockaddr *sap1, *sap2;
1127 	struct rpc_xprt *xprt1 = server1->client->cl_xprt;
1128 	struct rpc_xprt *xprt2 = server2->client->cl_xprt;
1129 
1130 	if (!net_eq(xprt1->xprt_net, xprt2->xprt_net))
1131 		return 0;
1132 
1133 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1134 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1135 
1136 	if (sap1->sa_family != sap2->sa_family)
1137 		return 0;
1138 
1139 	switch (sap1->sa_family) {
1140 	case AF_INET: {
1141 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1142 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1143 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1144 			return 0;
1145 		if (sin1->sin_port != sin2->sin_port)
1146 			return 0;
1147 		break;
1148 	}
1149 	case AF_INET6: {
1150 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1151 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1152 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1153 			return 0;
1154 		if (sin1->sin6_port != sin2->sin6_port)
1155 			return 0;
1156 		break;
1157 	}
1158 	default:
1159 		return 0;
1160 	}
1161 
1162 	return 1;
1163 }
1164 
1165 static int nfs_compare_userns(const struct nfs_server *old,
1166 		const struct nfs_server *new)
1167 {
1168 	const struct user_namespace *oldns = &init_user_ns;
1169 	const struct user_namespace *newns = &init_user_ns;
1170 
1171 	if (old->client && old->client->cl_cred)
1172 		oldns = old->client->cl_cred->user_ns;
1173 	if (new->client && new->client->cl_cred)
1174 		newns = new->client->cl_cred->user_ns;
1175 	if (oldns != newns)
1176 		return 0;
1177 	return 1;
1178 }
1179 
1180 static int nfs_compare_super(struct super_block *sb, struct fs_context *fc)
1181 {
1182 	struct nfs_server *server = fc->s_fs_info, *old = NFS_SB(sb);
1183 
1184 	if (!nfs_compare_super_address(old, server))
1185 		return 0;
1186 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1187 	if (old->flags & NFS_MOUNT_UNSHARED)
1188 		return 0;
1189 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1190 		return 0;
1191 	if (!nfs_compare_userns(old, server))
1192 		return 0;
1193 	if ((old->has_sec_mnt_opts || fc->security) &&
1194 			security_sb_mnt_opts_compat(sb, fc->security))
1195 		return 0;
1196 	return nfs_compare_mount_options(sb, server, fc);
1197 }
1198 
1199 #ifdef CONFIG_NFS_FSCACHE
1200 static void nfs_get_cache_cookie(struct super_block *sb,
1201 				 struct nfs_fs_context *ctx)
1202 {
1203 	struct nfs_server *nfss = NFS_SB(sb);
1204 	char *uniq = NULL;
1205 	int ulen = 0;
1206 
1207 	nfss->fscache_key = NULL;
1208 	nfss->fscache = NULL;
1209 
1210 	if (!ctx)
1211 		return;
1212 
1213 	if (ctx->clone_data.sb) {
1214 		struct nfs_server *mnt_s = NFS_SB(ctx->clone_data.sb);
1215 		if (!(mnt_s->options & NFS_OPTION_FSCACHE))
1216 			return;
1217 		if (mnt_s->fscache_key) {
1218 			uniq = mnt_s->fscache_key->key.uniquifier;
1219 			ulen = mnt_s->fscache_key->key.uniq_len;
1220 		}
1221 	} else {
1222 		if (!(ctx->options & NFS_OPTION_FSCACHE))
1223 			return;
1224 		if (ctx->fscache_uniq) {
1225 			uniq = ctx->fscache_uniq;
1226 			ulen = strlen(ctx->fscache_uniq);
1227 		}
1228 	}
1229 
1230 	nfs_fscache_get_super_cookie(sb, uniq, ulen);
1231 }
1232 #else
1233 static void nfs_get_cache_cookie(struct super_block *sb,
1234 				 struct nfs_fs_context *ctx)
1235 {
1236 }
1237 #endif
1238 
1239 int nfs_get_tree_common(struct fs_context *fc)
1240 {
1241 	struct nfs_fs_context *ctx = nfs_fc2context(fc);
1242 	struct super_block *s;
1243 	int (*compare_super)(struct super_block *, struct fs_context *) = nfs_compare_super;
1244 	struct nfs_server *server = ctx->server;
1245 	int error;
1246 
1247 	ctx->server = NULL;
1248 	if (IS_ERR(server))
1249 		return PTR_ERR(server);
1250 
1251 	if (server->flags & NFS_MOUNT_UNSHARED)
1252 		compare_super = NULL;
1253 
1254 	/* -o noac implies -o sync */
1255 	if (server->flags & NFS_MOUNT_NOAC)
1256 		fc->sb_flags |= SB_SYNCHRONOUS;
1257 
1258 	if (ctx->clone_data.sb)
1259 		if (ctx->clone_data.sb->s_flags & SB_SYNCHRONOUS)
1260 			fc->sb_flags |= SB_SYNCHRONOUS;
1261 
1262 	if (server->caps & NFS_CAP_SECURITY_LABEL)
1263 		fc->lsm_flags |= SECURITY_LSM_NATIVE_LABELS;
1264 
1265 	/* Get a superblock - note that we may end up sharing one that already exists */
1266 	fc->s_fs_info = server;
1267 	s = sget_fc(fc, compare_super, nfs_set_super);
1268 	fc->s_fs_info = NULL;
1269 	if (IS_ERR(s)) {
1270 		error = PTR_ERR(s);
1271 		nfs_errorf(fc, "NFS: Couldn't get superblock");
1272 		goto out_err_nosb;
1273 	}
1274 
1275 	if (s->s_fs_info != server) {
1276 		nfs_free_server(server);
1277 		server = NULL;
1278 	} else {
1279 		error = super_setup_bdi_name(s, "%u:%u", MAJOR(server->s_dev),
1280 					     MINOR(server->s_dev));
1281 		if (error)
1282 			goto error_splat_super;
1283 		s->s_bdi->io_pages = server->rpages;
1284 		server->super = s;
1285 	}
1286 
1287 	if (!s->s_root) {
1288 		unsigned bsize = ctx->clone_data.inherited_bsize;
1289 		/* initial superblock/root creation */
1290 		nfs_fill_super(s, ctx);
1291 		if (bsize) {
1292 			s->s_blocksize_bits = bsize;
1293 			s->s_blocksize = 1U << bsize;
1294 		}
1295 		nfs_get_cache_cookie(s, ctx);
1296 	}
1297 
1298 	error = nfs_get_root(s, fc);
1299 	if (error < 0) {
1300 		nfs_errorf(fc, "NFS: Couldn't get root dentry");
1301 		goto error_splat_super;
1302 	}
1303 
1304 	s->s_flags |= SB_ACTIVE;
1305 	error = 0;
1306 
1307 out:
1308 	return error;
1309 
1310 out_err_nosb:
1311 	nfs_free_server(server);
1312 	goto out;
1313 error_splat_super:
1314 	deactivate_locked_super(s);
1315 	goto out;
1316 }
1317 
1318 /*
1319  * Destroy an NFS2/3 superblock
1320  */
1321 void nfs_kill_super(struct super_block *s)
1322 {
1323 	struct nfs_server *server = NFS_SB(s);
1324 	dev_t dev = s->s_dev;
1325 
1326 	generic_shutdown_super(s);
1327 
1328 	nfs_fscache_release_super_cookie(s);
1329 
1330 	nfs_free_server(server);
1331 	free_anon_bdev(dev);
1332 }
1333 EXPORT_SYMBOL_GPL(nfs_kill_super);
1334 
1335 #if IS_ENABLED(CONFIG_NFS_V4)
1336 
1337 /*
1338  * NFS v4 module parameters need to stay in the
1339  * NFS client for backwards compatibility
1340  */
1341 unsigned int nfs_callback_set_tcpport;
1342 unsigned short nfs_callback_nr_threads;
1343 /* Default cache timeout is 10 minutes */
1344 unsigned int nfs_idmap_cache_timeout = 600;
1345 /* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
1346 bool nfs4_disable_idmapping = true;
1347 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
1348 unsigned short max_session_cb_slots = NFS4_DEF_CB_SLOT_TABLE_SIZE;
1349 unsigned short send_implementation_id = 1;
1350 char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
1351 bool recover_lost_locks = false;
1352 
1353 EXPORT_SYMBOL_GPL(nfs_callback_nr_threads);
1354 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
1355 EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
1356 EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
1357 EXPORT_SYMBOL_GPL(max_session_slots);
1358 EXPORT_SYMBOL_GPL(max_session_cb_slots);
1359 EXPORT_SYMBOL_GPL(send_implementation_id);
1360 EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
1361 EXPORT_SYMBOL_GPL(recover_lost_locks);
1362 
1363 #define NFS_CALLBACK_MAXPORTNR (65535U)
1364 
1365 static int param_set_portnr(const char *val, const struct kernel_param *kp)
1366 {
1367 	unsigned long num;
1368 	int ret;
1369 
1370 	if (!val)
1371 		return -EINVAL;
1372 	ret = kstrtoul(val, 0, &num);
1373 	if (ret || num > NFS_CALLBACK_MAXPORTNR)
1374 		return -EINVAL;
1375 	*((unsigned int *)kp->arg) = num;
1376 	return 0;
1377 }
1378 static const struct kernel_param_ops param_ops_portnr = {
1379 	.set = param_set_portnr,
1380 	.get = param_get_uint,
1381 };
1382 #define param_check_portnr(name, p) __param_check(name, p, unsigned int)
1383 
1384 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
1385 module_param_named(callback_nr_threads, nfs_callback_nr_threads, ushort, 0644);
1386 MODULE_PARM_DESC(callback_nr_threads, "Number of threads that will be "
1387 		"assigned to the NFSv4 callback channels.");
1388 module_param(nfs_idmap_cache_timeout, int, 0644);
1389 module_param(nfs4_disable_idmapping, bool, 0644);
1390 module_param_string(nfs4_unique_id, nfs4_client_id_uniquifier,
1391 			NFS4_CLIENT_ID_UNIQ_LEN, 0600);
1392 MODULE_PARM_DESC(nfs4_disable_idmapping,
1393 		"Turn off NFSv4 idmapping when using 'sec=sys'");
1394 module_param(max_session_slots, ushort, 0644);
1395 MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
1396 		"requests the client will negotiate");
1397 module_param(max_session_cb_slots, ushort, 0644);
1398 MODULE_PARM_DESC(max_session_cb_slots, "Maximum number of parallel NFSv4.1 "
1399 		"callbacks the client will process for a given server");
1400 module_param(send_implementation_id, ushort, 0644);
1401 MODULE_PARM_DESC(send_implementation_id,
1402 		"Send implementation ID with NFSv4.1 exchange_id");
1403 MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
1404 
1405 module_param(recover_lost_locks, bool, 0644);
1406 MODULE_PARM_DESC(recover_lost_locks,
1407 		 "If the server reports that a lock might be lost, "
1408 		 "try to recover it risking data corruption.");
1409 
1410 
1411 #endif /* CONFIG_NFS_V4 */
1412