xref: /linux/fs/nfs/super.c (revision 25aee3debe0464f6c680173041fa3de30ec9ff54)
1 /*
2  *  linux/fs/nfs/super.c
3  *
4  *  Copyright (C) 1992  Rick Sladkey
5  *
6  *  nfs superblock handling functions
7  *
8  *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
9  *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
10  *
11  *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
12  *  J.S.Peatfield@damtp.cam.ac.uk
13  *
14  *  Split from inode.c by David Howells <dhowells@redhat.com>
15  *
16  * - superblocks are indexed on server only - all inodes, dentries, etc. associated with a
17  *   particular server are held in the same superblock
18  * - NFS superblocks can have several effective roots to the dentry tree
19  * - directory type roots are spliced into the tree when a path from one root reaches the root
20  *   of another (see nfs_lookup())
21  */
22 
23 #include <linux/module.h>
24 #include <linux/init.h>
25 
26 #include <linux/time.h>
27 #include <linux/kernel.h>
28 #include <linux/mm.h>
29 #include <linux/string.h>
30 #include <linux/stat.h>
31 #include <linux/errno.h>
32 #include <linux/unistd.h>
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/stats.h>
35 #include <linux/sunrpc/metrics.h>
36 #include <linux/sunrpc/xprtsock.h>
37 #include <linux/sunrpc/xprtrdma.h>
38 #include <linux/nfs_fs.h>
39 #include <linux/nfs_mount.h>
40 #include <linux/nfs4_mount.h>
41 #include <linux/lockd/bind.h>
42 #include <linux/seq_file.h>
43 #include <linux/mount.h>
44 #include <linux/namei.h>
45 #include <linux/nfs_idmap.h>
46 #include <linux/vfs.h>
47 #include <linux/inet.h>
48 #include <linux/in6.h>
49 #include <linux/slab.h>
50 #include <net/ipv6.h>
51 #include <linux/netdevice.h>
52 #include <linux/nfs_xdr.h>
53 #include <linux/magic.h>
54 #include <linux/parser.h>
55 #include <linux/nsproxy.h>
56 #include <linux/rcupdate.h>
57 
58 #include <asm/uaccess.h>
59 
60 #include "nfs4_fs.h"
61 #include "callback.h"
62 #include "delegation.h"
63 #include "iostat.h"
64 #include "internal.h"
65 #include "fscache.h"
66 #include "pnfs.h"
67 #include "nfs.h"
68 
69 #define NFSDBG_FACILITY		NFSDBG_VFS
70 #define NFS_TEXT_DATA		1
71 
72 #if IS_ENABLED(CONFIG_NFS_V3)
73 #define NFS_DEFAULT_VERSION 3
74 #else
75 #define NFS_DEFAULT_VERSION 2
76 #endif
77 
78 enum {
79 	/* Mount options that take no arguments */
80 	Opt_soft, Opt_hard,
81 	Opt_posix, Opt_noposix,
82 	Opt_cto, Opt_nocto,
83 	Opt_ac, Opt_noac,
84 	Opt_lock, Opt_nolock,
85 	Opt_udp, Opt_tcp, Opt_rdma,
86 	Opt_acl, Opt_noacl,
87 	Opt_rdirplus, Opt_nordirplus,
88 	Opt_sharecache, Opt_nosharecache,
89 	Opt_resvport, Opt_noresvport,
90 	Opt_fscache, Opt_nofscache,
91 
92 	/* Mount options that take integer arguments */
93 	Opt_port,
94 	Opt_rsize, Opt_wsize, Opt_bsize,
95 	Opt_timeo, Opt_retrans,
96 	Opt_acregmin, Opt_acregmax,
97 	Opt_acdirmin, Opt_acdirmax,
98 	Opt_actimeo,
99 	Opt_namelen,
100 	Opt_mountport,
101 	Opt_mountvers,
102 	Opt_minorversion,
103 
104 	/* Mount options that take string arguments */
105 	Opt_nfsvers,
106 	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
107 	Opt_addr, Opt_mountaddr, Opt_clientaddr,
108 	Opt_lookupcache,
109 	Opt_fscache_uniq,
110 	Opt_local_lock,
111 
112 	/* Special mount options */
113 	Opt_userspace, Opt_deprecated, Opt_sloppy,
114 
115 	Opt_err
116 };
117 
118 static const match_table_t nfs_mount_option_tokens = {
119 	{ Opt_userspace, "bg" },
120 	{ Opt_userspace, "fg" },
121 	{ Opt_userspace, "retry=%s" },
122 
123 	{ Opt_sloppy, "sloppy" },
124 
125 	{ Opt_soft, "soft" },
126 	{ Opt_hard, "hard" },
127 	{ Opt_deprecated, "intr" },
128 	{ Opt_deprecated, "nointr" },
129 	{ Opt_posix, "posix" },
130 	{ Opt_noposix, "noposix" },
131 	{ Opt_cto, "cto" },
132 	{ Opt_nocto, "nocto" },
133 	{ Opt_ac, "ac" },
134 	{ Opt_noac, "noac" },
135 	{ Opt_lock, "lock" },
136 	{ Opt_nolock, "nolock" },
137 	{ Opt_udp, "udp" },
138 	{ Opt_tcp, "tcp" },
139 	{ Opt_rdma, "rdma" },
140 	{ Opt_acl, "acl" },
141 	{ Opt_noacl, "noacl" },
142 	{ Opt_rdirplus, "rdirplus" },
143 	{ Opt_nordirplus, "nordirplus" },
144 	{ Opt_sharecache, "sharecache" },
145 	{ Opt_nosharecache, "nosharecache" },
146 	{ Opt_resvport, "resvport" },
147 	{ Opt_noresvport, "noresvport" },
148 	{ Opt_fscache, "fsc" },
149 	{ Opt_nofscache, "nofsc" },
150 
151 	{ Opt_port, "port=%s" },
152 	{ Opt_rsize, "rsize=%s" },
153 	{ Opt_wsize, "wsize=%s" },
154 	{ Opt_bsize, "bsize=%s" },
155 	{ Opt_timeo, "timeo=%s" },
156 	{ Opt_retrans, "retrans=%s" },
157 	{ Opt_acregmin, "acregmin=%s" },
158 	{ Opt_acregmax, "acregmax=%s" },
159 	{ Opt_acdirmin, "acdirmin=%s" },
160 	{ Opt_acdirmax, "acdirmax=%s" },
161 	{ Opt_actimeo, "actimeo=%s" },
162 	{ Opt_namelen, "namlen=%s" },
163 	{ Opt_mountport, "mountport=%s" },
164 	{ Opt_mountvers, "mountvers=%s" },
165 	{ Opt_minorversion, "minorversion=%s" },
166 
167 	{ Opt_nfsvers, "nfsvers=%s" },
168 	{ Opt_nfsvers, "vers=%s" },
169 
170 	{ Opt_sec, "sec=%s" },
171 	{ Opt_proto, "proto=%s" },
172 	{ Opt_mountproto, "mountproto=%s" },
173 	{ Opt_addr, "addr=%s" },
174 	{ Opt_clientaddr, "clientaddr=%s" },
175 	{ Opt_mounthost, "mounthost=%s" },
176 	{ Opt_mountaddr, "mountaddr=%s" },
177 
178 	{ Opt_lookupcache, "lookupcache=%s" },
179 	{ Opt_fscache_uniq, "fsc=%s" },
180 	{ Opt_local_lock, "local_lock=%s" },
181 
182 	/* The following needs to be listed after all other options */
183 	{ Opt_nfsvers, "v%s" },
184 
185 	{ Opt_err, NULL }
186 };
187 
188 enum {
189 	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
190 
191 	Opt_xprt_err
192 };
193 
194 static const match_table_t nfs_xprt_protocol_tokens = {
195 	{ Opt_xprt_udp, "udp" },
196 	{ Opt_xprt_udp6, "udp6" },
197 	{ Opt_xprt_tcp, "tcp" },
198 	{ Opt_xprt_tcp6, "tcp6" },
199 	{ Opt_xprt_rdma, "rdma" },
200 
201 	{ Opt_xprt_err, NULL }
202 };
203 
204 enum {
205 	Opt_sec_none, Opt_sec_sys,
206 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
207 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
208 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
209 
210 	Opt_sec_err
211 };
212 
213 static const match_table_t nfs_secflavor_tokens = {
214 	{ Opt_sec_none, "none" },
215 	{ Opt_sec_none, "null" },
216 	{ Opt_sec_sys, "sys" },
217 
218 	{ Opt_sec_krb5, "krb5" },
219 	{ Opt_sec_krb5i, "krb5i" },
220 	{ Opt_sec_krb5p, "krb5p" },
221 
222 	{ Opt_sec_lkey, "lkey" },
223 	{ Opt_sec_lkeyi, "lkeyi" },
224 	{ Opt_sec_lkeyp, "lkeyp" },
225 
226 	{ Opt_sec_spkm, "spkm3" },
227 	{ Opt_sec_spkmi, "spkm3i" },
228 	{ Opt_sec_spkmp, "spkm3p" },
229 
230 	{ Opt_sec_err, NULL }
231 };
232 
233 enum {
234 	Opt_lookupcache_all, Opt_lookupcache_positive,
235 	Opt_lookupcache_none,
236 
237 	Opt_lookupcache_err
238 };
239 
240 static match_table_t nfs_lookupcache_tokens = {
241 	{ Opt_lookupcache_all, "all" },
242 	{ Opt_lookupcache_positive, "pos" },
243 	{ Opt_lookupcache_positive, "positive" },
244 	{ Opt_lookupcache_none, "none" },
245 
246 	{ Opt_lookupcache_err, NULL }
247 };
248 
249 enum {
250 	Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
251 	Opt_local_lock_none,
252 
253 	Opt_local_lock_err
254 };
255 
256 static match_table_t nfs_local_lock_tokens = {
257 	{ Opt_local_lock_all, "all" },
258 	{ Opt_local_lock_flock, "flock" },
259 	{ Opt_local_lock_posix, "posix" },
260 	{ Opt_local_lock_none, "none" },
261 
262 	{ Opt_local_lock_err, NULL }
263 };
264 
265 enum {
266 	Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
267 	Opt_vers_4_1,
268 
269 	Opt_vers_err
270 };
271 
272 static match_table_t nfs_vers_tokens = {
273 	{ Opt_vers_2, "2" },
274 	{ Opt_vers_3, "3" },
275 	{ Opt_vers_4, "4" },
276 	{ Opt_vers_4_0, "4.0" },
277 	{ Opt_vers_4_1, "4.1" },
278 
279 	{ Opt_vers_err, NULL }
280 };
281 
282 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
283 		int flags, const char *dev_name, void *raw_data);
284 
285 struct file_system_type nfs_fs_type = {
286 	.owner		= THIS_MODULE,
287 	.name		= "nfs",
288 	.mount		= nfs_fs_mount,
289 	.kill_sb	= nfs_kill_super,
290 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
291 };
292 EXPORT_SYMBOL_GPL(nfs_fs_type);
293 
294 struct file_system_type nfs_xdev_fs_type = {
295 	.owner		= THIS_MODULE,
296 	.name		= "nfs",
297 	.mount		= nfs_xdev_mount,
298 	.kill_sb	= nfs_kill_super,
299 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
300 };
301 
302 const struct super_operations nfs_sops = {
303 	.alloc_inode	= nfs_alloc_inode,
304 	.destroy_inode	= nfs_destroy_inode,
305 	.write_inode	= nfs_write_inode,
306 	.put_super	= nfs_put_super,
307 	.statfs		= nfs_statfs,
308 	.evict_inode	= nfs_evict_inode,
309 	.umount_begin	= nfs_umount_begin,
310 	.show_options	= nfs_show_options,
311 	.show_devname	= nfs_show_devname,
312 	.show_path	= nfs_show_path,
313 	.show_stats	= nfs_show_stats,
314 	.remount_fs	= nfs_remount,
315 };
316 EXPORT_SYMBOL_GPL(nfs_sops);
317 
318 #if IS_ENABLED(CONFIG_NFS_V4)
319 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *);
320 static int nfs4_validate_mount_data(void *options,
321 	struct nfs_parsed_mount_data *args, const char *dev_name);
322 #endif
323 
324 static struct shrinker acl_shrinker = {
325 	.shrink		= nfs_access_cache_shrinker,
326 	.seeks		= DEFAULT_SEEKS,
327 };
328 
329 /*
330  * Register the NFS filesystems
331  */
332 int __init register_nfs_fs(void)
333 {
334 	int ret;
335 
336         ret = register_filesystem(&nfs_fs_type);
337 	if (ret < 0)
338 		goto error_0;
339 
340 	ret = nfs_register_sysctl();
341 	if (ret < 0)
342 		goto error_1;
343 	register_shrinker(&acl_shrinker);
344 	return 0;
345 
346 error_1:
347 	unregister_filesystem(&nfs_fs_type);
348 error_0:
349 	return ret;
350 }
351 
352 /*
353  * Unregister the NFS filesystems
354  */
355 void __exit unregister_nfs_fs(void)
356 {
357 	unregister_shrinker(&acl_shrinker);
358 	nfs_unregister_sysctl();
359 	unregister_filesystem(&nfs_fs_type);
360 }
361 
362 void nfs_sb_active(struct super_block *sb)
363 {
364 	struct nfs_server *server = NFS_SB(sb);
365 
366 	if (atomic_inc_return(&server->active) == 1)
367 		atomic_inc(&sb->s_active);
368 }
369 EXPORT_SYMBOL_GPL(nfs_sb_active);
370 
371 void nfs_sb_deactive(struct super_block *sb)
372 {
373 	struct nfs_server *server = NFS_SB(sb);
374 
375 	if (atomic_dec_and_test(&server->active))
376 		deactivate_super(sb);
377 }
378 EXPORT_SYMBOL_GPL(nfs_sb_deactive);
379 
380 /*
381  * Deliver file system statistics to userspace
382  */
383 int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
384 {
385 	struct nfs_server *server = NFS_SB(dentry->d_sb);
386 	unsigned char blockbits;
387 	unsigned long blockres;
388 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
389 	struct nfs_fsstat res;
390 	int error = -ENOMEM;
391 
392 	res.fattr = nfs_alloc_fattr();
393 	if (res.fattr == NULL)
394 		goto out_err;
395 
396 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
397 	if (unlikely(error == -ESTALE)) {
398 		struct dentry *pd_dentry;
399 
400 		pd_dentry = dget_parent(dentry);
401 		if (pd_dentry != NULL) {
402 			nfs_zap_caches(pd_dentry->d_inode);
403 			dput(pd_dentry);
404 		}
405 	}
406 	nfs_free_fattr(res.fattr);
407 	if (error < 0)
408 		goto out_err;
409 
410 	buf->f_type = NFS_SUPER_MAGIC;
411 
412 	/*
413 	 * Current versions of glibc do not correctly handle the
414 	 * case where f_frsize != f_bsize.  Eventually we want to
415 	 * report the value of wtmult in this field.
416 	 */
417 	buf->f_frsize = dentry->d_sb->s_blocksize;
418 
419 	/*
420 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
421 	 * are reported in units of f_frsize.  Linux hasn't had
422 	 * an f_frsize field in its statfs struct until recently,
423 	 * thus historically Linux's sys_statfs reports these
424 	 * fields in units of f_bsize.
425 	 */
426 	buf->f_bsize = dentry->d_sb->s_blocksize;
427 	blockbits = dentry->d_sb->s_blocksize_bits;
428 	blockres = (1 << blockbits) - 1;
429 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
430 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
431 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
432 
433 	buf->f_files = res.tfiles;
434 	buf->f_ffree = res.afiles;
435 
436 	buf->f_namelen = server->namelen;
437 
438 	return 0;
439 
440  out_err:
441 	dprintk("%s: statfs error = %d\n", __func__, -error);
442 	return error;
443 }
444 EXPORT_SYMBOL_GPL(nfs_statfs);
445 
446 /*
447  * Map the security flavour number to a name
448  */
449 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
450 {
451 	static const struct {
452 		rpc_authflavor_t flavour;
453 		const char *str;
454 	} sec_flavours[] = {
455 		{ RPC_AUTH_NULL, "null" },
456 		{ RPC_AUTH_UNIX, "sys" },
457 		{ RPC_AUTH_GSS_KRB5, "krb5" },
458 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
459 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
460 		{ RPC_AUTH_GSS_LKEY, "lkey" },
461 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
462 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
463 		{ RPC_AUTH_GSS_SPKM, "spkm" },
464 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
465 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
466 		{ UINT_MAX, "unknown" }
467 	};
468 	int i;
469 
470 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
471 		if (sec_flavours[i].flavour == flavour)
472 			break;
473 	}
474 	return sec_flavours[i].str;
475 }
476 
477 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
478 				  int showdefaults)
479 {
480 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
481 
482 	seq_printf(m, ",mountproto=");
483 	switch (sap->sa_family) {
484 	case AF_INET:
485 		switch (nfss->mountd_protocol) {
486 		case IPPROTO_UDP:
487 			seq_printf(m, RPCBIND_NETID_UDP);
488 			break;
489 		case IPPROTO_TCP:
490 			seq_printf(m, RPCBIND_NETID_TCP);
491 			break;
492 		default:
493 			if (showdefaults)
494 				seq_printf(m, "auto");
495 		}
496 		break;
497 	case AF_INET6:
498 		switch (nfss->mountd_protocol) {
499 		case IPPROTO_UDP:
500 			seq_printf(m, RPCBIND_NETID_UDP6);
501 			break;
502 		case IPPROTO_TCP:
503 			seq_printf(m, RPCBIND_NETID_TCP6);
504 			break;
505 		default:
506 			if (showdefaults)
507 				seq_printf(m, "auto");
508 		}
509 		break;
510 	default:
511 		if (showdefaults)
512 			seq_printf(m, "auto");
513 	}
514 }
515 
516 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
517 				    int showdefaults)
518 {
519 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
520 
521 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
522 		return;
523 
524 	switch (sap->sa_family) {
525 	case AF_INET: {
526 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
527 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
528 		break;
529 	}
530 	case AF_INET6: {
531 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
532 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
533 		break;
534 	}
535 	default:
536 		if (showdefaults)
537 			seq_printf(m, ",mountaddr=unspecified");
538 	}
539 
540 	if (nfss->mountd_version || showdefaults)
541 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
542 	if ((nfss->mountd_port &&
543 		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
544 		showdefaults)
545 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
546 
547 	nfs_show_mountd_netid(m, nfss, showdefaults);
548 }
549 
550 #if IS_ENABLED(CONFIG_NFS_V4)
551 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
552 				    int showdefaults)
553 {
554 	struct nfs_client *clp = nfss->nfs_client;
555 
556 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
557 }
558 #else
559 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
560 				    int showdefaults)
561 {
562 }
563 #endif
564 
565 static void nfs_show_nfs_version(struct seq_file *m,
566 		unsigned int version,
567 		unsigned int minorversion)
568 {
569 	seq_printf(m, ",vers=%u", version);
570 	if (version == 4)
571 		seq_printf(m, ".%u", minorversion);
572 }
573 
574 /*
575  * Describe the mount options in force on this server representation
576  */
577 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
578 				   int showdefaults)
579 {
580 	static const struct proc_nfs_info {
581 		int flag;
582 		const char *str;
583 		const char *nostr;
584 	} nfs_info[] = {
585 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
586 		{ NFS_MOUNT_POSIX, ",posix", "" },
587 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
588 		{ NFS_MOUNT_NOAC, ",noac", "" },
589 		{ NFS_MOUNT_NONLM, ",nolock", "" },
590 		{ NFS_MOUNT_NOACL, ",noacl", "" },
591 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
592 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
593 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
594 		{ 0, NULL, NULL }
595 	};
596 	const struct proc_nfs_info *nfs_infop;
597 	struct nfs_client *clp = nfss->nfs_client;
598 	u32 version = clp->rpc_ops->version;
599 	int local_flock, local_fcntl;
600 
601 	nfs_show_nfs_version(m, version, clp->cl_minorversion);
602 	seq_printf(m, ",rsize=%u", nfss->rsize);
603 	seq_printf(m, ",wsize=%u", nfss->wsize);
604 	if (nfss->bsize != 0)
605 		seq_printf(m, ",bsize=%u", nfss->bsize);
606 	seq_printf(m, ",namlen=%u", nfss->namelen);
607 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
608 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
609 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
610 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
611 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
612 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
613 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
614 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
615 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
616 		if (nfss->flags & nfs_infop->flag)
617 			seq_puts(m, nfs_infop->str);
618 		else
619 			seq_puts(m, nfs_infop->nostr);
620 	}
621 	rcu_read_lock();
622 	seq_printf(m, ",proto=%s",
623 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
624 	rcu_read_unlock();
625 	if (version == 4) {
626 		if (nfss->port != NFS_PORT)
627 			seq_printf(m, ",port=%u", nfss->port);
628 	} else
629 		if (nfss->port)
630 			seq_printf(m, ",port=%u", nfss->port);
631 
632 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
633 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
634 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
635 
636 	if (version != 4)
637 		nfs_show_mountd_options(m, nfss, showdefaults);
638 	else
639 		nfs_show_nfsv4_options(m, nfss, showdefaults);
640 
641 	if (nfss->options & NFS_OPTION_FSCACHE)
642 		seq_printf(m, ",fsc");
643 
644 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
645 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
646 			seq_printf(m, ",lookupcache=none");
647 		else
648 			seq_printf(m, ",lookupcache=pos");
649 	}
650 
651 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
652 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
653 
654 	if (!local_flock && !local_fcntl)
655 		seq_printf(m, ",local_lock=none");
656 	else if (local_flock && local_fcntl)
657 		seq_printf(m, ",local_lock=all");
658 	else if (local_flock)
659 		seq_printf(m, ",local_lock=flock");
660 	else
661 		seq_printf(m, ",local_lock=posix");
662 }
663 
664 /*
665  * Describe the mount options on this VFS mountpoint
666  */
667 int nfs_show_options(struct seq_file *m, struct dentry *root)
668 {
669 	struct nfs_server *nfss = NFS_SB(root->d_sb);
670 
671 	nfs_show_mount_options(m, nfss, 0);
672 
673 	rcu_read_lock();
674 	seq_printf(m, ",addr=%s",
675 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
676 							RPC_DISPLAY_ADDR));
677 	rcu_read_unlock();
678 
679 	return 0;
680 }
681 EXPORT_SYMBOL_GPL(nfs_show_options);
682 
683 #if IS_ENABLED(CONFIG_NFS_V4)
684 #ifdef CONFIG_NFS_V4_1
685 static void show_sessions(struct seq_file *m, struct nfs_server *server)
686 {
687 	if (nfs4_has_session(server->nfs_client))
688 		seq_printf(m, ",sessions");
689 }
690 #else
691 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
692 #endif
693 #endif
694 
695 #ifdef CONFIG_NFS_V4_1
696 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
697 {
698 	seq_printf(m, ",pnfs=");
699 	if (server->pnfs_curr_ld)
700 		seq_printf(m, "%s", server->pnfs_curr_ld->name);
701 	else
702 		seq_printf(m, "not configured");
703 }
704 
705 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
706 {
707 	if (nfss->nfs_client && nfss->nfs_client->cl_implid) {
708 		struct nfs41_impl_id *impl_id = nfss->nfs_client->cl_implid;
709 		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
710 			   "date='%llu,%u'",
711 			   impl_id->name, impl_id->domain,
712 			   impl_id->date.seconds, impl_id->date.nseconds);
713 	}
714 }
715 #else
716 #if IS_ENABLED(CONFIG_NFS_V4)
717 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
718 {
719 }
720 #endif
721 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
722 {
723 }
724 #endif
725 
726 int nfs_show_devname(struct seq_file *m, struct dentry *root)
727 {
728 	char *page = (char *) __get_free_page(GFP_KERNEL);
729 	char *devname, *dummy;
730 	int err = 0;
731 	if (!page)
732 		return -ENOMEM;
733 	devname = nfs_path(&dummy, root, page, PAGE_SIZE);
734 	if (IS_ERR(devname))
735 		err = PTR_ERR(devname);
736 	else
737 		seq_escape(m, devname, " \t\n\\");
738 	free_page((unsigned long)page);
739 	return err;
740 }
741 EXPORT_SYMBOL_GPL(nfs_show_devname);
742 
743 int nfs_show_path(struct seq_file *m, struct dentry *dentry)
744 {
745 	seq_puts(m, "/");
746 	return 0;
747 }
748 EXPORT_SYMBOL_GPL(nfs_show_path);
749 
750 /*
751  * Present statistical information for this VFS mountpoint
752  */
753 int nfs_show_stats(struct seq_file *m, struct dentry *root)
754 {
755 	int i, cpu;
756 	struct nfs_server *nfss = NFS_SB(root->d_sb);
757 	struct rpc_auth *auth = nfss->client->cl_auth;
758 	struct nfs_iostats totals = { };
759 
760 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
761 
762 	/*
763 	 * Display all mount option settings
764 	 */
765 	seq_printf(m, "\n\topts:\t");
766 	seq_puts(m, root->d_sb->s_flags & MS_RDONLY ? "ro" : "rw");
767 	seq_puts(m, root->d_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
768 	seq_puts(m, root->d_sb->s_flags & MS_NOATIME ? ",noatime" : "");
769 	seq_puts(m, root->d_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
770 	nfs_show_mount_options(m, nfss, 1);
771 
772 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
773 
774 	show_implementation_id(m, nfss);
775 
776 	seq_printf(m, "\n\tcaps:\t");
777 	seq_printf(m, "caps=0x%x", nfss->caps);
778 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
779 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
780 	seq_printf(m, ",bsize=%u", nfss->bsize);
781 	seq_printf(m, ",namlen=%u", nfss->namelen);
782 
783 #if IS_ENABLED(CONFIG_NFS_V4)
784 	if (nfss->nfs_client->rpc_ops->version == 4) {
785 		seq_printf(m, "\n\tnfsv4:\t");
786 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
787 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
788 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
789 		show_sessions(m, nfss);
790 		show_pnfs(m, nfss);
791 	}
792 #endif
793 
794 	/*
795 	 * Display security flavor in effect for this mount
796 	 */
797 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
798 	if (auth->au_flavor)
799 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
800 
801 	/*
802 	 * Display superblock I/O counters
803 	 */
804 	for_each_possible_cpu(cpu) {
805 		struct nfs_iostats *stats;
806 
807 		preempt_disable();
808 		stats = per_cpu_ptr(nfss->io_stats, cpu);
809 
810 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
811 			totals.events[i] += stats->events[i];
812 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
813 			totals.bytes[i] += stats->bytes[i];
814 #ifdef CONFIG_NFS_FSCACHE
815 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
816 			totals.fscache[i] += stats->fscache[i];
817 #endif
818 
819 		preempt_enable();
820 	}
821 
822 	seq_printf(m, "\n\tevents:\t");
823 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
824 		seq_printf(m, "%lu ", totals.events[i]);
825 	seq_printf(m, "\n\tbytes:\t");
826 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
827 		seq_printf(m, "%Lu ", totals.bytes[i]);
828 #ifdef CONFIG_NFS_FSCACHE
829 	if (nfss->options & NFS_OPTION_FSCACHE) {
830 		seq_printf(m, "\n\tfsc:\t");
831 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
832 			seq_printf(m, "%Lu ", totals.bytes[i]);
833 	}
834 #endif
835 	seq_printf(m, "\n");
836 
837 	rpc_print_iostats(m, nfss->client);
838 
839 	return 0;
840 }
841 EXPORT_SYMBOL_GPL(nfs_show_stats);
842 
843 /*
844  * Begin unmount by attempting to remove all automounted mountpoints we added
845  * in response to xdev traversals and referrals
846  */
847 void nfs_umount_begin(struct super_block *sb)
848 {
849 	struct nfs_server *server;
850 	struct rpc_clnt *rpc;
851 
852 	server = NFS_SB(sb);
853 	/* -EIO all pending I/O */
854 	rpc = server->client_acl;
855 	if (!IS_ERR(rpc))
856 		rpc_killall_tasks(rpc);
857 	rpc = server->client;
858 	if (!IS_ERR(rpc))
859 		rpc_killall_tasks(rpc);
860 }
861 EXPORT_SYMBOL_GPL(nfs_umount_begin);
862 
863 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(void)
864 {
865 	struct nfs_parsed_mount_data *data;
866 
867 	data = kzalloc(sizeof(*data), GFP_KERNEL);
868 	if (data) {
869 		data->acregmin		= NFS_DEF_ACREGMIN;
870 		data->acregmax		= NFS_DEF_ACREGMAX;
871 		data->acdirmin		= NFS_DEF_ACDIRMIN;
872 		data->acdirmax		= NFS_DEF_ACDIRMAX;
873 		data->mount_server.port	= NFS_UNSPEC_PORT;
874 		data->nfs_server.port	= NFS_UNSPEC_PORT;
875 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
876 		data->auth_flavors[0]	= RPC_AUTH_UNIX;
877 		data->auth_flavor_len	= 1;
878 		data->minorversion	= 0;
879 		data->need_mount	= true;
880 		data->net		= current->nsproxy->net_ns;
881 		security_init_mnt_opts(&data->lsm_opts);
882 	}
883 	return data;
884 }
885 
886 static void nfs_free_parsed_mount_data(struct nfs_parsed_mount_data *data)
887 {
888 	if (data) {
889 		kfree(data->client_address);
890 		kfree(data->mount_server.hostname);
891 		kfree(data->nfs_server.export_path);
892 		kfree(data->nfs_server.hostname);
893 		kfree(data->fscache_uniq);
894 		security_free_mnt_opts(&data->lsm_opts);
895 		kfree(data);
896 	}
897 }
898 
899 /*
900  * Sanity-check a server address provided by the mount command.
901  *
902  * Address family must be initialized, and address must not be
903  * the ANY address for that family.
904  */
905 static int nfs_verify_server_address(struct sockaddr *addr)
906 {
907 	switch (addr->sa_family) {
908 	case AF_INET: {
909 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
910 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
911 	}
912 	case AF_INET6: {
913 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
914 		return !ipv6_addr_any(sa);
915 	}
916 	}
917 
918 	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
919 	return 0;
920 }
921 
922 /*
923  * Select between a default port value and a user-specified port value.
924  * If a zero value is set, then autobind will be used.
925  */
926 static void nfs_set_port(struct sockaddr *sap, int *port,
927 				 const unsigned short default_port)
928 {
929 	if (*port == NFS_UNSPEC_PORT)
930 		*port = default_port;
931 
932 	rpc_set_port(sap, *port);
933 }
934 
935 /*
936  * Sanity check the NFS transport protocol.
937  *
938  */
939 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
940 {
941 	switch (mnt->nfs_server.protocol) {
942 	case XPRT_TRANSPORT_UDP:
943 	case XPRT_TRANSPORT_TCP:
944 	case XPRT_TRANSPORT_RDMA:
945 		break;
946 	default:
947 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
948 	}
949 }
950 
951 /*
952  * For text based NFSv2/v3 mounts, the mount protocol transport default
953  * settings should depend upon the specified NFS transport.
954  */
955 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
956 {
957 	nfs_validate_transport_protocol(mnt);
958 
959 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
960 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
961 			return;
962 	switch (mnt->nfs_server.protocol) {
963 	case XPRT_TRANSPORT_UDP:
964 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
965 		break;
966 	case XPRT_TRANSPORT_TCP:
967 	case XPRT_TRANSPORT_RDMA:
968 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
969 	}
970 }
971 
972 /*
973  * Parse the value of the 'sec=' option.
974  */
975 static int nfs_parse_security_flavors(char *value,
976 				      struct nfs_parsed_mount_data *mnt)
977 {
978 	substring_t args[MAX_OPT_ARGS];
979 
980 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
981 
982 	switch (match_token(value, nfs_secflavor_tokens, args)) {
983 	case Opt_sec_none:
984 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
985 		break;
986 	case Opt_sec_sys:
987 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
988 		break;
989 	case Opt_sec_krb5:
990 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
991 		break;
992 	case Opt_sec_krb5i:
993 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
994 		break;
995 	case Opt_sec_krb5p:
996 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
997 		break;
998 	case Opt_sec_lkey:
999 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
1000 		break;
1001 	case Opt_sec_lkeyi:
1002 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
1003 		break;
1004 	case Opt_sec_lkeyp:
1005 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
1006 		break;
1007 	case Opt_sec_spkm:
1008 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
1009 		break;
1010 	case Opt_sec_spkmi:
1011 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
1012 		break;
1013 	case Opt_sec_spkmp:
1014 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
1015 		break;
1016 	default:
1017 		return 0;
1018 	}
1019 
1020 	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
1021 	mnt->auth_flavor_len = 1;
1022 	return 1;
1023 }
1024 
1025 static int nfs_parse_version_string(char *string,
1026 		struct nfs_parsed_mount_data *mnt,
1027 		substring_t *args)
1028 {
1029 	mnt->flags &= ~NFS_MOUNT_VER3;
1030 	switch (match_token(string, nfs_vers_tokens, args)) {
1031 	case Opt_vers_2:
1032 		mnt->version = 2;
1033 		break;
1034 	case Opt_vers_3:
1035 		mnt->flags |= NFS_MOUNT_VER3;
1036 		mnt->version = 3;
1037 		break;
1038 	case Opt_vers_4:
1039 		/* Backward compatibility option. In future,
1040 		 * the mount program should always supply
1041 		 * a NFSv4 minor version number.
1042 		 */
1043 		mnt->version = 4;
1044 		break;
1045 	case Opt_vers_4_0:
1046 		mnt->version = 4;
1047 		mnt->minorversion = 0;
1048 		break;
1049 	case Opt_vers_4_1:
1050 		mnt->version = 4;
1051 		mnt->minorversion = 1;
1052 		break;
1053 	default:
1054 		return 0;
1055 	}
1056 	return 1;
1057 }
1058 
1059 static int nfs_get_option_str(substring_t args[], char **option)
1060 {
1061 	kfree(*option);
1062 	*option = match_strdup(args);
1063 	return !option;
1064 }
1065 
1066 static int nfs_get_option_ul(substring_t args[], unsigned long *option)
1067 {
1068 	int rc;
1069 	char *string;
1070 
1071 	string = match_strdup(args);
1072 	if (string == NULL)
1073 		return -ENOMEM;
1074 	rc = strict_strtoul(string, 10, option);
1075 	kfree(string);
1076 
1077 	return rc;
1078 }
1079 
1080 /*
1081  * Error-check and convert a string of mount options from user space into
1082  * a data structure.  The whole mount string is processed; bad options are
1083  * skipped as they are encountered.  If there were no errors, return 1;
1084  * otherwise return 0 (zero).
1085  */
1086 static int nfs_parse_mount_options(char *raw,
1087 				   struct nfs_parsed_mount_data *mnt)
1088 {
1089 	char *p, *string, *secdata;
1090 	int rc, sloppy = 0, invalid_option = 0;
1091 	unsigned short protofamily = AF_UNSPEC;
1092 	unsigned short mountfamily = AF_UNSPEC;
1093 
1094 	if (!raw) {
1095 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
1096 		return 1;
1097 	}
1098 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
1099 
1100 	secdata = alloc_secdata();
1101 	if (!secdata)
1102 		goto out_nomem;
1103 
1104 	rc = security_sb_copy_data(raw, secdata);
1105 	if (rc)
1106 		goto out_security_failure;
1107 
1108 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1109 	if (rc)
1110 		goto out_security_failure;
1111 
1112 	free_secdata(secdata);
1113 
1114 	while ((p = strsep(&raw, ",")) != NULL) {
1115 		substring_t args[MAX_OPT_ARGS];
1116 		unsigned long option;
1117 		int token;
1118 
1119 		if (!*p)
1120 			continue;
1121 
1122 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1123 
1124 		token = match_token(p, nfs_mount_option_tokens, args);
1125 		switch (token) {
1126 
1127 		/*
1128 		 * boolean options:  foo/nofoo
1129 		 */
1130 		case Opt_soft:
1131 			mnt->flags |= NFS_MOUNT_SOFT;
1132 			break;
1133 		case Opt_hard:
1134 			mnt->flags &= ~NFS_MOUNT_SOFT;
1135 			break;
1136 		case Opt_posix:
1137 			mnt->flags |= NFS_MOUNT_POSIX;
1138 			break;
1139 		case Opt_noposix:
1140 			mnt->flags &= ~NFS_MOUNT_POSIX;
1141 			break;
1142 		case Opt_cto:
1143 			mnt->flags &= ~NFS_MOUNT_NOCTO;
1144 			break;
1145 		case Opt_nocto:
1146 			mnt->flags |= NFS_MOUNT_NOCTO;
1147 			break;
1148 		case Opt_ac:
1149 			mnt->flags &= ~NFS_MOUNT_NOAC;
1150 			break;
1151 		case Opt_noac:
1152 			mnt->flags |= NFS_MOUNT_NOAC;
1153 			break;
1154 		case Opt_lock:
1155 			mnt->flags &= ~NFS_MOUNT_NONLM;
1156 			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1157 					NFS_MOUNT_LOCAL_FCNTL);
1158 			break;
1159 		case Opt_nolock:
1160 			mnt->flags |= NFS_MOUNT_NONLM;
1161 			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1162 				       NFS_MOUNT_LOCAL_FCNTL);
1163 			break;
1164 		case Opt_udp:
1165 			mnt->flags &= ~NFS_MOUNT_TCP;
1166 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1167 			break;
1168 		case Opt_tcp:
1169 			mnt->flags |= NFS_MOUNT_TCP;
1170 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1171 			break;
1172 		case Opt_rdma:
1173 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1174 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1175 			xprt_load_transport(p);
1176 			break;
1177 		case Opt_acl:
1178 			mnt->flags &= ~NFS_MOUNT_NOACL;
1179 			break;
1180 		case Opt_noacl:
1181 			mnt->flags |= NFS_MOUNT_NOACL;
1182 			break;
1183 		case Opt_rdirplus:
1184 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1185 			break;
1186 		case Opt_nordirplus:
1187 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1188 			break;
1189 		case Opt_sharecache:
1190 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1191 			break;
1192 		case Opt_nosharecache:
1193 			mnt->flags |= NFS_MOUNT_UNSHARED;
1194 			break;
1195 		case Opt_resvport:
1196 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1197 			break;
1198 		case Opt_noresvport:
1199 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1200 			break;
1201 		case Opt_fscache:
1202 			mnt->options |= NFS_OPTION_FSCACHE;
1203 			kfree(mnt->fscache_uniq);
1204 			mnt->fscache_uniq = NULL;
1205 			break;
1206 		case Opt_nofscache:
1207 			mnt->options &= ~NFS_OPTION_FSCACHE;
1208 			kfree(mnt->fscache_uniq);
1209 			mnt->fscache_uniq = NULL;
1210 			break;
1211 
1212 		/*
1213 		 * options that take numeric values
1214 		 */
1215 		case Opt_port:
1216 			if (nfs_get_option_ul(args, &option) ||
1217 			    option > USHRT_MAX)
1218 				goto out_invalid_value;
1219 			mnt->nfs_server.port = option;
1220 			break;
1221 		case Opt_rsize:
1222 			if (nfs_get_option_ul(args, &option))
1223 				goto out_invalid_value;
1224 			mnt->rsize = option;
1225 			break;
1226 		case Opt_wsize:
1227 			if (nfs_get_option_ul(args, &option))
1228 				goto out_invalid_value;
1229 			mnt->wsize = option;
1230 			break;
1231 		case Opt_bsize:
1232 			if (nfs_get_option_ul(args, &option))
1233 				goto out_invalid_value;
1234 			mnt->bsize = option;
1235 			break;
1236 		case Opt_timeo:
1237 			if (nfs_get_option_ul(args, &option) || option == 0)
1238 				goto out_invalid_value;
1239 			mnt->timeo = option;
1240 			break;
1241 		case Opt_retrans:
1242 			if (nfs_get_option_ul(args, &option) || option == 0)
1243 				goto out_invalid_value;
1244 			mnt->retrans = option;
1245 			break;
1246 		case Opt_acregmin:
1247 			if (nfs_get_option_ul(args, &option))
1248 				goto out_invalid_value;
1249 			mnt->acregmin = option;
1250 			break;
1251 		case Opt_acregmax:
1252 			if (nfs_get_option_ul(args, &option))
1253 				goto out_invalid_value;
1254 			mnt->acregmax = option;
1255 			break;
1256 		case Opt_acdirmin:
1257 			if (nfs_get_option_ul(args, &option))
1258 				goto out_invalid_value;
1259 			mnt->acdirmin = option;
1260 			break;
1261 		case Opt_acdirmax:
1262 			if (nfs_get_option_ul(args, &option))
1263 				goto out_invalid_value;
1264 			mnt->acdirmax = option;
1265 			break;
1266 		case Opt_actimeo:
1267 			if (nfs_get_option_ul(args, &option))
1268 				goto out_invalid_value;
1269 			mnt->acregmin = mnt->acregmax =
1270 			mnt->acdirmin = mnt->acdirmax = option;
1271 			break;
1272 		case Opt_namelen:
1273 			if (nfs_get_option_ul(args, &option))
1274 				goto out_invalid_value;
1275 			mnt->namlen = option;
1276 			break;
1277 		case Opt_mountport:
1278 			if (nfs_get_option_ul(args, &option) ||
1279 			    option > USHRT_MAX)
1280 				goto out_invalid_value;
1281 			mnt->mount_server.port = option;
1282 			break;
1283 		case Opt_mountvers:
1284 			if (nfs_get_option_ul(args, &option) ||
1285 			    option < NFS_MNT_VERSION ||
1286 			    option > NFS_MNT3_VERSION)
1287 				goto out_invalid_value;
1288 			mnt->mount_server.version = option;
1289 			break;
1290 		case Opt_minorversion:
1291 			if (nfs_get_option_ul(args, &option))
1292 				goto out_invalid_value;
1293 			if (option > NFS4_MAX_MINOR_VERSION)
1294 				goto out_invalid_value;
1295 			mnt->minorversion = option;
1296 			break;
1297 
1298 		/*
1299 		 * options that take text values
1300 		 */
1301 		case Opt_nfsvers:
1302 			string = match_strdup(args);
1303 			if (string == NULL)
1304 				goto out_nomem;
1305 			rc = nfs_parse_version_string(string, mnt, args);
1306 			kfree(string);
1307 			if (!rc)
1308 				goto out_invalid_value;
1309 			break;
1310 		case Opt_sec:
1311 			string = match_strdup(args);
1312 			if (string == NULL)
1313 				goto out_nomem;
1314 			rc = nfs_parse_security_flavors(string, mnt);
1315 			kfree(string);
1316 			if (!rc) {
1317 				dfprintk(MOUNT, "NFS:   unrecognized "
1318 						"security flavor\n");
1319 				return 0;
1320 			}
1321 			break;
1322 		case Opt_proto:
1323 			string = match_strdup(args);
1324 			if (string == NULL)
1325 				goto out_nomem;
1326 			token = match_token(string,
1327 					    nfs_xprt_protocol_tokens, args);
1328 
1329 			protofamily = AF_INET;
1330 			switch (token) {
1331 			case Opt_xprt_udp6:
1332 				protofamily = AF_INET6;
1333 			case Opt_xprt_udp:
1334 				mnt->flags &= ~NFS_MOUNT_TCP;
1335 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1336 				break;
1337 			case Opt_xprt_tcp6:
1338 				protofamily = AF_INET6;
1339 			case Opt_xprt_tcp:
1340 				mnt->flags |= NFS_MOUNT_TCP;
1341 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1342 				break;
1343 			case Opt_xprt_rdma:
1344 				/* vector side protocols to TCP */
1345 				mnt->flags |= NFS_MOUNT_TCP;
1346 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1347 				xprt_load_transport(string);
1348 				break;
1349 			default:
1350 				dfprintk(MOUNT, "NFS:   unrecognized "
1351 						"transport protocol\n");
1352 				kfree(string);
1353 				return 0;
1354 			}
1355 			kfree(string);
1356 			break;
1357 		case Opt_mountproto:
1358 			string = match_strdup(args);
1359 			if (string == NULL)
1360 				goto out_nomem;
1361 			token = match_token(string,
1362 					    nfs_xprt_protocol_tokens, args);
1363 			kfree(string);
1364 
1365 			mountfamily = AF_INET;
1366 			switch (token) {
1367 			case Opt_xprt_udp6:
1368 				mountfamily = AF_INET6;
1369 			case Opt_xprt_udp:
1370 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1371 				break;
1372 			case Opt_xprt_tcp6:
1373 				mountfamily = AF_INET6;
1374 			case Opt_xprt_tcp:
1375 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1376 				break;
1377 			case Opt_xprt_rdma: /* not used for side protocols */
1378 			default:
1379 				dfprintk(MOUNT, "NFS:   unrecognized "
1380 						"transport protocol\n");
1381 				return 0;
1382 			}
1383 			break;
1384 		case Opt_addr:
1385 			string = match_strdup(args);
1386 			if (string == NULL)
1387 				goto out_nomem;
1388 			mnt->nfs_server.addrlen =
1389 				rpc_pton(mnt->net, string, strlen(string),
1390 					(struct sockaddr *)
1391 					&mnt->nfs_server.address,
1392 					sizeof(mnt->nfs_server.address));
1393 			kfree(string);
1394 			if (mnt->nfs_server.addrlen == 0)
1395 				goto out_invalid_address;
1396 			break;
1397 		case Opt_clientaddr:
1398 			if (nfs_get_option_str(args, &mnt->client_address))
1399 				goto out_nomem;
1400 			break;
1401 		case Opt_mounthost:
1402 			if (nfs_get_option_str(args,
1403 					       &mnt->mount_server.hostname))
1404 				goto out_nomem;
1405 			break;
1406 		case Opt_mountaddr:
1407 			string = match_strdup(args);
1408 			if (string == NULL)
1409 				goto out_nomem;
1410 			mnt->mount_server.addrlen =
1411 				rpc_pton(mnt->net, string, strlen(string),
1412 					(struct sockaddr *)
1413 					&mnt->mount_server.address,
1414 					sizeof(mnt->mount_server.address));
1415 			kfree(string);
1416 			if (mnt->mount_server.addrlen == 0)
1417 				goto out_invalid_address;
1418 			break;
1419 		case Opt_lookupcache:
1420 			string = match_strdup(args);
1421 			if (string == NULL)
1422 				goto out_nomem;
1423 			token = match_token(string,
1424 					nfs_lookupcache_tokens, args);
1425 			kfree(string);
1426 			switch (token) {
1427 				case Opt_lookupcache_all:
1428 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1429 					break;
1430 				case Opt_lookupcache_positive:
1431 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1432 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1433 					break;
1434 				case Opt_lookupcache_none:
1435 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1436 					break;
1437 				default:
1438 					dfprintk(MOUNT, "NFS:   invalid "
1439 							"lookupcache argument\n");
1440 					return 0;
1441 			};
1442 			break;
1443 		case Opt_fscache_uniq:
1444 			if (nfs_get_option_str(args, &mnt->fscache_uniq))
1445 				goto out_nomem;
1446 			mnt->options |= NFS_OPTION_FSCACHE;
1447 			break;
1448 		case Opt_local_lock:
1449 			string = match_strdup(args);
1450 			if (string == NULL)
1451 				goto out_nomem;
1452 			token = match_token(string, nfs_local_lock_tokens,
1453 					args);
1454 			kfree(string);
1455 			switch (token) {
1456 			case Opt_local_lock_all:
1457 				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1458 					       NFS_MOUNT_LOCAL_FCNTL);
1459 				break;
1460 			case Opt_local_lock_flock:
1461 				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1462 				break;
1463 			case Opt_local_lock_posix:
1464 				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1465 				break;
1466 			case Opt_local_lock_none:
1467 				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1468 						NFS_MOUNT_LOCAL_FCNTL);
1469 				break;
1470 			default:
1471 				dfprintk(MOUNT, "NFS:	invalid	"
1472 						"local_lock argument\n");
1473 				return 0;
1474 			};
1475 			break;
1476 
1477 		/*
1478 		 * Special options
1479 		 */
1480 		case Opt_sloppy:
1481 			sloppy = 1;
1482 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1483 			break;
1484 		case Opt_userspace:
1485 		case Opt_deprecated:
1486 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1487 					"'%s'\n", p);
1488 			break;
1489 
1490 		default:
1491 			invalid_option = 1;
1492 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1493 					"'%s'\n", p);
1494 		}
1495 	}
1496 
1497 	if (!sloppy && invalid_option)
1498 		return 0;
1499 
1500 	if (mnt->minorversion && mnt->version != 4)
1501 		goto out_minorversion_mismatch;
1502 
1503 	/*
1504 	 * verify that any proto=/mountproto= options match the address
1505 	 * familiies in the addr=/mountaddr= options.
1506 	 */
1507 	if (protofamily != AF_UNSPEC &&
1508 	    protofamily != mnt->nfs_server.address.ss_family)
1509 		goto out_proto_mismatch;
1510 
1511 	if (mountfamily != AF_UNSPEC) {
1512 		if (mnt->mount_server.addrlen) {
1513 			if (mountfamily != mnt->mount_server.address.ss_family)
1514 				goto out_mountproto_mismatch;
1515 		} else {
1516 			if (mountfamily != mnt->nfs_server.address.ss_family)
1517 				goto out_mountproto_mismatch;
1518 		}
1519 	}
1520 
1521 	return 1;
1522 
1523 out_mountproto_mismatch:
1524 	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1525 			 "option\n");
1526 	return 0;
1527 out_proto_mismatch:
1528 	printk(KERN_INFO "NFS: server address does not match proto= option\n");
1529 	return 0;
1530 out_invalid_address:
1531 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1532 	return 0;
1533 out_invalid_value:
1534 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1535 	return 0;
1536 out_minorversion_mismatch:
1537 	printk(KERN_INFO "NFS: mount option vers=%u does not support "
1538 			 "minorversion=%u\n", mnt->version, mnt->minorversion);
1539 	return 0;
1540 out_nomem:
1541 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1542 	return 0;
1543 out_security_failure:
1544 	free_secdata(secdata);
1545 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1546 	return 0;
1547 }
1548 
1549 /*
1550  * Match the requested auth flavors with the list returned by
1551  * the server.  Returns zero and sets the mount's authentication
1552  * flavor on success; returns -EACCES if server does not support
1553  * the requested flavor.
1554  */
1555 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1556 			     struct nfs_mount_request *request)
1557 {
1558 	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1559 
1560 	/*
1561 	 * Certain releases of Linux's mountd return an empty
1562 	 * flavor list.  To prevent behavioral regression with
1563 	 * these servers (ie. rejecting mounts that used to
1564 	 * succeed), revert to pre-2.6.32 behavior (no checking)
1565 	 * if the returned flavor list is empty.
1566 	 */
1567 	if (server_authlist_len == 0)
1568 		return 0;
1569 
1570 	/*
1571 	 * We avoid sophisticated negotiating here, as there are
1572 	 * plenty of cases where we can get it wrong, providing
1573 	 * either too little or too much security.
1574 	 *
1575 	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
1576 	 * flavor listed first.  However, some servers list
1577 	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1578 	 * preferred default, in args->auth_flavors[0] if user
1579 	 * didn't specify sec= mount option.
1580 	 */
1581 	for (i = 0; i < args->auth_flavor_len; i++)
1582 		for (j = 0; j < server_authlist_len; j++)
1583 			if (args->auth_flavors[i] == request->auth_flavs[j]) {
1584 				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1585 					request->auth_flavs[j]);
1586 				args->auth_flavors[0] = request->auth_flavs[j];
1587 				return 0;
1588 			}
1589 
1590 	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1591 	nfs_umount(request);
1592 	return -EACCES;
1593 }
1594 
1595 /*
1596  * Use the remote server's MOUNT service to request the NFS file handle
1597  * corresponding to the provided path.
1598  */
1599 static int nfs_request_mount(struct nfs_parsed_mount_data *args,
1600 			     struct nfs_fh *root_fh)
1601 {
1602 	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1603 	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1604 	struct nfs_mount_request request = {
1605 		.sap		= (struct sockaddr *)
1606 						&args->mount_server.address,
1607 		.dirpath	= args->nfs_server.export_path,
1608 		.protocol	= args->mount_server.protocol,
1609 		.fh		= root_fh,
1610 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1611 		.auth_flav_len	= &server_authlist_len,
1612 		.auth_flavs	= server_authlist,
1613 		.net		= args->net,
1614 	};
1615 	int status;
1616 
1617 	if (args->mount_server.version == 0) {
1618 		switch (args->version) {
1619 			default:
1620 				args->mount_server.version = NFS_MNT3_VERSION;
1621 				break;
1622 			case 2:
1623 				args->mount_server.version = NFS_MNT_VERSION;
1624 		}
1625 	}
1626 	request.version = args->mount_server.version;
1627 
1628 	if (args->mount_server.hostname)
1629 		request.hostname = args->mount_server.hostname;
1630 	else
1631 		request.hostname = args->nfs_server.hostname;
1632 
1633 	/*
1634 	 * Construct the mount server's address.
1635 	 */
1636 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1637 		memcpy(request.sap, &args->nfs_server.address,
1638 		       args->nfs_server.addrlen);
1639 		args->mount_server.addrlen = args->nfs_server.addrlen;
1640 	}
1641 	request.salen = args->mount_server.addrlen;
1642 	nfs_set_port(request.sap, &args->mount_server.port, 0);
1643 
1644 	/*
1645 	 * Now ask the mount server to map our export path
1646 	 * to a file handle.
1647 	 */
1648 	status = nfs_mount(&request);
1649 	if (status != 0) {
1650 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1651 				request.hostname, status);
1652 		return status;
1653 	}
1654 
1655 	/*
1656 	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
1657 	 */
1658 	if (args->mount_server.version != NFS_MNT3_VERSION)
1659 		return 0;
1660 	return nfs_walk_authlist(args, &request);
1661 }
1662 
1663 struct dentry *nfs_try_mount(int flags, const char *dev_name,
1664 			     struct nfs_mount_info *mount_info,
1665 			     struct nfs_subversion *nfs_mod)
1666 {
1667 	int status;
1668 	struct nfs_server *server;
1669 
1670 	if (mount_info->parsed->need_mount) {
1671 		status = nfs_request_mount(mount_info->parsed, mount_info->mntfh);
1672 		if (status)
1673 			return ERR_PTR(status);
1674 	}
1675 
1676 	/* Get a volume representation */
1677 	server = nfs_mod->rpc_ops->create_server(mount_info, nfs_mod);
1678 	if (IS_ERR(server))
1679 		return ERR_CAST(server);
1680 
1681 	return nfs_fs_mount_common(server, flags, dev_name, mount_info, nfs_mod);
1682 }
1683 EXPORT_SYMBOL_GPL(nfs_try_mount);
1684 
1685 /*
1686  * Split "dev_name" into "hostname:export_path".
1687  *
1688  * The leftmost colon demarks the split between the server's hostname
1689  * and the export path.  If the hostname starts with a left square
1690  * bracket, then it may contain colons.
1691  *
1692  * Note: caller frees hostname and export path, even on error.
1693  */
1694 static int nfs_parse_devname(const char *dev_name,
1695 			     char **hostname, size_t maxnamlen,
1696 			     char **export_path, size_t maxpathlen)
1697 {
1698 	size_t len;
1699 	char *end;
1700 
1701 	/* Is the host name protected with square brakcets? */
1702 	if (*dev_name == '[') {
1703 		end = strchr(++dev_name, ']');
1704 		if (end == NULL || end[1] != ':')
1705 			goto out_bad_devname;
1706 
1707 		len = end - dev_name;
1708 		end++;
1709 	} else {
1710 		char *comma;
1711 
1712 		end = strchr(dev_name, ':');
1713 		if (end == NULL)
1714 			goto out_bad_devname;
1715 		len = end - dev_name;
1716 
1717 		/* kill possible hostname list: not supported */
1718 		comma = strchr(dev_name, ',');
1719 		if (comma != NULL && comma < end)
1720 			*comma = 0;
1721 	}
1722 
1723 	if (len > maxnamlen)
1724 		goto out_hostname;
1725 
1726 	/* N.B. caller will free nfs_server.hostname in all cases */
1727 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1728 	if (*hostname == NULL)
1729 		goto out_nomem;
1730 	len = strlen(++end);
1731 	if (len > maxpathlen)
1732 		goto out_path;
1733 	*export_path = kstrndup(end, len, GFP_KERNEL);
1734 	if (!*export_path)
1735 		goto out_nomem;
1736 
1737 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1738 	return 0;
1739 
1740 out_bad_devname:
1741 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1742 	return -EINVAL;
1743 
1744 out_nomem:
1745 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1746 	return -ENOMEM;
1747 
1748 out_hostname:
1749 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1750 	return -ENAMETOOLONG;
1751 
1752 out_path:
1753 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1754 	return -ENAMETOOLONG;
1755 }
1756 
1757 /*
1758  * Validate the NFS2/NFS3 mount data
1759  * - fills in the mount root filehandle
1760  *
1761  * For option strings, user space handles the following behaviors:
1762  *
1763  * + DNS: mapping server host name to IP address ("addr=" option)
1764  *
1765  * + failure mode: how to behave if a mount request can't be handled
1766  *   immediately ("fg/bg" option)
1767  *
1768  * + retry: how often to retry a mount request ("retry=" option)
1769  *
1770  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1771  *   mountproto=tcp after mountproto=udp, and so on
1772  */
1773 static int nfs23_validate_mount_data(void *options,
1774 				     struct nfs_parsed_mount_data *args,
1775 				     struct nfs_fh *mntfh,
1776 				     const char *dev_name)
1777 {
1778 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1779 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1780 
1781 	if (data == NULL)
1782 		goto out_no_data;
1783 
1784 	args->version = NFS_DEFAULT_VERSION;
1785 	switch (data->version) {
1786 	case 1:
1787 		data->namlen = 0;
1788 	case 2:
1789 		data->bsize = 0;
1790 	case 3:
1791 		if (data->flags & NFS_MOUNT_VER3)
1792 			goto out_no_v3;
1793 		data->root.size = NFS2_FHSIZE;
1794 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1795 	case 4:
1796 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1797 			goto out_no_sec;
1798 	case 5:
1799 		memset(data->context, 0, sizeof(data->context));
1800 	case 6:
1801 		if (data->flags & NFS_MOUNT_VER3) {
1802 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1803 				goto out_invalid_fh;
1804 			mntfh->size = data->root.size;
1805 			args->version = 3;
1806 		} else {
1807 			mntfh->size = NFS2_FHSIZE;
1808 			args->version = 2;
1809 		}
1810 
1811 
1812 		memcpy(mntfh->data, data->root.data, mntfh->size);
1813 		if (mntfh->size < sizeof(mntfh->data))
1814 			memset(mntfh->data + mntfh->size, 0,
1815 			       sizeof(mntfh->data) - mntfh->size);
1816 
1817 		/*
1818 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1819 		 * can deal with.
1820 		 */
1821 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1822 		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
1823 		args->rsize		= data->rsize;
1824 		args->wsize		= data->wsize;
1825 		args->timeo		= data->timeo;
1826 		args->retrans		= data->retrans;
1827 		args->acregmin		= data->acregmin;
1828 		args->acregmax		= data->acregmax;
1829 		args->acdirmin		= data->acdirmin;
1830 		args->acdirmax		= data->acdirmax;
1831 		args->need_mount	= false;
1832 
1833 		memcpy(sap, &data->addr, sizeof(data->addr));
1834 		args->nfs_server.addrlen = sizeof(data->addr);
1835 		if (!nfs_verify_server_address(sap))
1836 			goto out_no_address;
1837 
1838 		if (!(data->flags & NFS_MOUNT_TCP))
1839 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1840 		/* N.B. caller will free nfs_server.hostname in all cases */
1841 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1842 		args->namlen		= data->namlen;
1843 		args->bsize		= data->bsize;
1844 
1845 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1846 			args->auth_flavors[0] = data->pseudoflavor;
1847 		if (!args->nfs_server.hostname)
1848 			goto out_nomem;
1849 
1850 		if (!(data->flags & NFS_MOUNT_NONLM))
1851 			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1852 					 NFS_MOUNT_LOCAL_FCNTL);
1853 		else
1854 			args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1855 					NFS_MOUNT_LOCAL_FCNTL);
1856 		/*
1857 		 * The legacy version 6 binary mount data from userspace has a
1858 		 * field used only to transport selinux information into the
1859 		 * the kernel.  To continue to support that functionality we
1860 		 * have a touch of selinux knowledge here in the NFS code. The
1861 		 * userspace code converted context=blah to just blah so we are
1862 		 * converting back to the full string selinux understands.
1863 		 */
1864 		if (data->context[0]){
1865 #ifdef CONFIG_SECURITY_SELINUX
1866 			int rc;
1867 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1868 			if (!opts_str)
1869 				return -ENOMEM;
1870 			strcpy(opts_str, "context=");
1871 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1872 			strcat(opts_str, &data->context[0]);
1873 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1874 			kfree(opts_str);
1875 			if (rc)
1876 				return rc;
1877 #else
1878 			return -EINVAL;
1879 #endif
1880 		}
1881 
1882 		break;
1883 	default:
1884 		return NFS_TEXT_DATA;
1885 	}
1886 
1887 #if !IS_ENABLED(CONFIG_NFS_V3)
1888 	if (args->version == 3)
1889 		goto out_v3_not_compiled;
1890 #endif /* !CONFIG_NFS_V3 */
1891 
1892 	return 0;
1893 
1894 out_no_data:
1895 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1896 	return -EINVAL;
1897 
1898 out_no_v3:
1899 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1900 		 data->version);
1901 	return -EINVAL;
1902 
1903 out_no_sec:
1904 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1905 	return -EINVAL;
1906 
1907 #if !IS_ENABLED(CONFIG_NFS_V3)
1908 out_v3_not_compiled:
1909 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1910 	return -EPROTONOSUPPORT;
1911 #endif /* !CONFIG_NFS_V3 */
1912 
1913 out_nomem:
1914 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1915 	return -ENOMEM;
1916 
1917 out_no_address:
1918 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1919 	return -EINVAL;
1920 
1921 out_invalid_fh:
1922 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1923 	return -EINVAL;
1924 }
1925 
1926 #if IS_ENABLED(CONFIG_NFS_V4)
1927 static int nfs_validate_mount_data(struct file_system_type *fs_type,
1928 				   void *options,
1929 				   struct nfs_parsed_mount_data *args,
1930 				   struct nfs_fh *mntfh,
1931 				   const char *dev_name)
1932 {
1933 	if (fs_type == &nfs_fs_type)
1934 		return nfs23_validate_mount_data(options, args, mntfh, dev_name);
1935 	return nfs4_validate_mount_data(options, args, dev_name);
1936 }
1937 #else
1938 static int nfs_validate_mount_data(struct file_system_type *fs_type,
1939 				   void *options,
1940 				   struct nfs_parsed_mount_data *args,
1941 				   struct nfs_fh *mntfh,
1942 				   const char *dev_name)
1943 {
1944 	return nfs23_validate_mount_data(options, args, mntfh, dev_name);
1945 }
1946 #endif
1947 
1948 static int nfs_validate_text_mount_data(void *options,
1949 					struct nfs_parsed_mount_data *args,
1950 					const char *dev_name)
1951 {
1952 	int port = 0;
1953 	int max_namelen = PAGE_SIZE;
1954 	int max_pathlen = NFS_MAXPATHLEN;
1955 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1956 
1957 	if (nfs_parse_mount_options((char *)options, args) == 0)
1958 		return -EINVAL;
1959 
1960 	if (!nfs_verify_server_address(sap))
1961 		goto out_no_address;
1962 
1963 	if (args->version == 4) {
1964 #if IS_ENABLED(CONFIG_NFS_V4)
1965 		port = NFS_PORT;
1966 		max_namelen = NFS4_MAXNAMLEN;
1967 		max_pathlen = NFS4_MAXPATHLEN;
1968 		nfs_validate_transport_protocol(args);
1969 		nfs4_validate_mount_flags(args);
1970 #else
1971 		goto out_v4_not_compiled;
1972 #endif /* CONFIG_NFS_V4 */
1973 	} else
1974 		nfs_set_mount_transport_protocol(args);
1975 
1976 	nfs_set_port(sap, &args->nfs_server.port, port);
1977 
1978 	if (args->auth_flavor_len > 1)
1979 		goto out_bad_auth;
1980 
1981 	return nfs_parse_devname(dev_name,
1982 				   &args->nfs_server.hostname,
1983 				   max_namelen,
1984 				   &args->nfs_server.export_path,
1985 				   max_pathlen);
1986 
1987 #if !IS_ENABLED(CONFIG_NFS_V4)
1988 out_v4_not_compiled:
1989 	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1990 	return -EPROTONOSUPPORT;
1991 #endif /* !CONFIG_NFS_V4 */
1992 
1993 out_no_address:
1994 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1995 	return -EINVAL;
1996 
1997 out_bad_auth:
1998 	dfprintk(MOUNT, "NFS: Too many RPC auth flavours specified\n");
1999 	return -EINVAL;
2000 }
2001 
2002 static int
2003 nfs_compare_remount_data(struct nfs_server *nfss,
2004 			 struct nfs_parsed_mount_data *data)
2005 {
2006 	if (data->flags != nfss->flags ||
2007 	    data->rsize != nfss->rsize ||
2008 	    data->wsize != nfss->wsize ||
2009 	    data->retrans != nfss->client->cl_timeout->to_retries ||
2010 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2011 	    data->acregmin != nfss->acregmin / HZ ||
2012 	    data->acregmax != nfss->acregmax / HZ ||
2013 	    data->acdirmin != nfss->acdirmin / HZ ||
2014 	    data->acdirmax != nfss->acdirmax / HZ ||
2015 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2016 	    data->nfs_server.port != nfss->port ||
2017 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2018 	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2019 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
2020 		return -EINVAL;
2021 
2022 	return 0;
2023 }
2024 
2025 int
2026 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2027 {
2028 	int error;
2029 	struct nfs_server *nfss = sb->s_fs_info;
2030 	struct nfs_parsed_mount_data *data;
2031 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2032 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2033 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2034 
2035 	/*
2036 	 * Userspace mount programs that send binary options generally send
2037 	 * them populated with default values. We have no way to know which
2038 	 * ones were explicitly specified. Fall back to legacy behavior and
2039 	 * just return success.
2040 	 */
2041 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2042 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
2043 					   options->version <= 6))))
2044 		return 0;
2045 
2046 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2047 	if (data == NULL)
2048 		return -ENOMEM;
2049 
2050 	/* fill out struct with values from existing mount */
2051 	data->flags = nfss->flags;
2052 	data->rsize = nfss->rsize;
2053 	data->wsize = nfss->wsize;
2054 	data->retrans = nfss->client->cl_timeout->to_retries;
2055 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2056 	data->acregmin = nfss->acregmin / HZ;
2057 	data->acregmax = nfss->acregmax / HZ;
2058 	data->acdirmin = nfss->acdirmin / HZ;
2059 	data->acdirmax = nfss->acdirmax / HZ;
2060 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2061 	data->nfs_server.port = nfss->port;
2062 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2063 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2064 		data->nfs_server.addrlen);
2065 
2066 	/* overwrite those values with any that were specified */
2067 	error = nfs_parse_mount_options((char *)options, data);
2068 	if (error < 0)
2069 		goto out;
2070 
2071 	/*
2072 	 * noac is a special case. It implies -o sync, but that's not
2073 	 * necessarily reflected in the mtab options. do_remount_sb
2074 	 * will clear MS_SYNCHRONOUS if -o sync wasn't specified in the
2075 	 * remount options, so we have to explicitly reset it.
2076 	 */
2077 	if (data->flags & NFS_MOUNT_NOAC)
2078 		*flags |= MS_SYNCHRONOUS;
2079 
2080 	/* compare new mount options with old ones */
2081 	error = nfs_compare_remount_data(nfss, data);
2082 out:
2083 	kfree(data);
2084 	return error;
2085 }
2086 EXPORT_SYMBOL_GPL(nfs_remount);
2087 
2088 /*
2089  * Initialise the common bits of the superblock
2090  */
2091 inline void nfs_initialise_sb(struct super_block *sb)
2092 {
2093 	struct nfs_server *server = NFS_SB(sb);
2094 
2095 	sb->s_magic = NFS_SUPER_MAGIC;
2096 
2097 	/* We probably want something more informative here */
2098 	snprintf(sb->s_id, sizeof(sb->s_id),
2099 		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2100 
2101 	if (sb->s_blocksize == 0)
2102 		sb->s_blocksize = nfs_block_bits(server->wsize,
2103 						 &sb->s_blocksize_bits);
2104 
2105 	sb->s_bdi = &server->backing_dev_info;
2106 
2107 	nfs_super_set_maxbytes(sb, server->maxfilesize);
2108 }
2109 
2110 /*
2111  * Finish setting up an NFS2/3 superblock
2112  */
2113 void nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
2114 {
2115 	struct nfs_parsed_mount_data *data = mount_info->parsed;
2116 	struct nfs_server *server = NFS_SB(sb);
2117 
2118 	sb->s_blocksize_bits = 0;
2119 	sb->s_blocksize = 0;
2120 	sb->s_xattr = server->nfs_client->cl_nfs_mod->xattr;
2121 	sb->s_op = server->nfs_client->cl_nfs_mod->sops;
2122 	if (data && data->bsize)
2123 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2124 
2125 	if (server->nfs_client->rpc_ops->version != 2) {
2126 		/* The VFS shouldn't apply the umask to mode bits. We will do
2127 		 * so ourselves when necessary.
2128 		 */
2129 		sb->s_flags |= MS_POSIXACL;
2130 		sb->s_time_gran = 1;
2131 	}
2132 
2133  	nfs_initialise_sb(sb);
2134 }
2135 EXPORT_SYMBOL_GPL(nfs_fill_super);
2136 
2137 /*
2138  * Finish setting up a cloned NFS2/3/4 superblock
2139  */
2140 void nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
2141 {
2142 	const struct super_block *old_sb = mount_info->cloned->sb;
2143 	struct nfs_server *server = NFS_SB(sb);
2144 
2145 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2146 	sb->s_blocksize = old_sb->s_blocksize;
2147 	sb->s_maxbytes = old_sb->s_maxbytes;
2148 	sb->s_xattr = old_sb->s_xattr;
2149 	sb->s_op = old_sb->s_op;
2150 	sb->s_time_gran = 1;
2151 
2152 	if (server->nfs_client->rpc_ops->version != 2) {
2153 		/* The VFS shouldn't apply the umask to mode bits. We will do
2154 		 * so ourselves when necessary.
2155 		 */
2156 		sb->s_flags |= MS_POSIXACL;
2157 	}
2158 
2159  	nfs_initialise_sb(sb);
2160 }
2161 
2162 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2163 {
2164 	const struct nfs_server *a = s->s_fs_info;
2165 	const struct rpc_clnt *clnt_a = a->client;
2166 	const struct rpc_clnt *clnt_b = b->client;
2167 
2168 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2169 		goto Ebusy;
2170 	if (a->nfs_client != b->nfs_client)
2171 		goto Ebusy;
2172 	if (a->flags != b->flags)
2173 		goto Ebusy;
2174 	if (a->wsize != b->wsize)
2175 		goto Ebusy;
2176 	if (a->rsize != b->rsize)
2177 		goto Ebusy;
2178 	if (a->acregmin != b->acregmin)
2179 		goto Ebusy;
2180 	if (a->acregmax != b->acregmax)
2181 		goto Ebusy;
2182 	if (a->acdirmin != b->acdirmin)
2183 		goto Ebusy;
2184 	if (a->acdirmax != b->acdirmax)
2185 		goto Ebusy;
2186 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2187 		goto Ebusy;
2188 	return 1;
2189 Ebusy:
2190 	return 0;
2191 }
2192 
2193 struct nfs_sb_mountdata {
2194 	struct nfs_server *server;
2195 	int mntflags;
2196 };
2197 
2198 static int nfs_set_super(struct super_block *s, void *data)
2199 {
2200 	struct nfs_sb_mountdata *sb_mntdata = data;
2201 	struct nfs_server *server = sb_mntdata->server;
2202 	int ret;
2203 
2204 	s->s_flags = sb_mntdata->mntflags;
2205 	s->s_fs_info = server;
2206 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
2207 	ret = set_anon_super(s, server);
2208 	if (ret == 0)
2209 		server->s_dev = s->s_dev;
2210 	return ret;
2211 }
2212 
2213 static int nfs_compare_super_address(struct nfs_server *server1,
2214 				     struct nfs_server *server2)
2215 {
2216 	struct sockaddr *sap1, *sap2;
2217 
2218 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2219 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2220 
2221 	if (sap1->sa_family != sap2->sa_family)
2222 		return 0;
2223 
2224 	switch (sap1->sa_family) {
2225 	case AF_INET: {
2226 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2227 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2228 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2229 			return 0;
2230 		if (sin1->sin_port != sin2->sin_port)
2231 			return 0;
2232 		break;
2233 	}
2234 	case AF_INET6: {
2235 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2236 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2237 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2238 			return 0;
2239 		if (sin1->sin6_port != sin2->sin6_port)
2240 			return 0;
2241 		break;
2242 	}
2243 	default:
2244 		return 0;
2245 	}
2246 
2247 	return 1;
2248 }
2249 
2250 static int nfs_compare_super(struct super_block *sb, void *data)
2251 {
2252 	struct nfs_sb_mountdata *sb_mntdata = data;
2253 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2254 	int mntflags = sb_mntdata->mntflags;
2255 
2256 	if (!nfs_compare_super_address(old, server))
2257 		return 0;
2258 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2259 	if (old->flags & NFS_MOUNT_UNSHARED)
2260 		return 0;
2261 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2262 		return 0;
2263 	return nfs_compare_mount_options(sb, server, mntflags);
2264 }
2265 
2266 #ifdef CONFIG_NFS_FSCACHE
2267 static void nfs_get_cache_cookie(struct super_block *sb,
2268 				 struct nfs_parsed_mount_data *parsed,
2269 				 struct nfs_clone_mount *cloned)
2270 {
2271 	char *uniq = NULL;
2272 	int ulen = 0;
2273 
2274 	if (parsed && parsed->fscache_uniq) {
2275 		uniq = parsed->fscache_uniq;
2276 		ulen = strlen(parsed->fscache_uniq);
2277 	} else if (cloned) {
2278 		struct nfs_server *mnt_s = NFS_SB(cloned->sb);
2279 		if (mnt_s->fscache_key) {
2280 			uniq = mnt_s->fscache_key->key.uniquifier;
2281 			ulen = mnt_s->fscache_key->key.uniq_len;
2282 		};
2283 	}
2284 
2285 	nfs_fscache_get_super_cookie(sb, uniq, ulen);
2286 }
2287 #else
2288 static void nfs_get_cache_cookie(struct super_block *sb,
2289 				 struct nfs_parsed_mount_data *parsed,
2290 				 struct nfs_clone_mount *cloned)
2291 {
2292 }
2293 #endif
2294 
2295 static int nfs_bdi_register(struct nfs_server *server)
2296 {
2297 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2298 }
2299 
2300 int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
2301 			struct nfs_mount_info *mount_info)
2302 {
2303 	return security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts);
2304 }
2305 EXPORT_SYMBOL_GPL(nfs_set_sb_security);
2306 
2307 int nfs_clone_sb_security(struct super_block *s, struct dentry *mntroot,
2308 			  struct nfs_mount_info *mount_info)
2309 {
2310 	/* clone any lsm security options from the parent to the new sb */
2311 	security_sb_clone_mnt_opts(mount_info->cloned->sb, s);
2312 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops)
2313 		return -ESTALE;
2314 	return 0;
2315 }
2316 EXPORT_SYMBOL_GPL(nfs_clone_sb_security);
2317 
2318 struct dentry *nfs_fs_mount_common(struct nfs_server *server,
2319 				   int flags, const char *dev_name,
2320 				   struct nfs_mount_info *mount_info,
2321 				   struct nfs_subversion *nfs_mod)
2322 {
2323 	struct super_block *s;
2324 	struct dentry *mntroot = ERR_PTR(-ENOMEM);
2325 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2326 	struct nfs_sb_mountdata sb_mntdata = {
2327 		.mntflags = flags,
2328 		.server = server,
2329 	};
2330 	int error;
2331 
2332 	if (server->flags & NFS_MOUNT_UNSHARED)
2333 		compare_super = NULL;
2334 
2335 	/* -o noac implies -o sync */
2336 	if (server->flags & NFS_MOUNT_NOAC)
2337 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
2338 
2339 	/* Get a superblock - note that we may end up sharing one that already exists */
2340 	s = sget(nfs_mod->nfs_fs, compare_super, nfs_set_super, flags, &sb_mntdata);
2341 	if (IS_ERR(s)) {
2342 		mntroot = ERR_CAST(s);
2343 		goto out_err_nosb;
2344 	}
2345 
2346 	if (s->s_fs_info != server) {
2347 		nfs_free_server(server);
2348 		server = NULL;
2349 	} else {
2350 		error = nfs_bdi_register(server);
2351 		if (error) {
2352 			mntroot = ERR_PTR(error);
2353 			goto error_splat_bdi;
2354 		}
2355 	}
2356 
2357 	if (!s->s_root) {
2358 		/* initial superblock/root creation */
2359 		mount_info->fill_super(s, mount_info);
2360 		nfs_get_cache_cookie(s, mount_info->parsed, mount_info->cloned);
2361 	}
2362 
2363 	mntroot = nfs_get_root(s, mount_info->mntfh, dev_name);
2364 	if (IS_ERR(mntroot))
2365 		goto error_splat_super;
2366 
2367 	error = mount_info->set_security(s, mntroot, mount_info);
2368 	if (error)
2369 		goto error_splat_root;
2370 
2371 	s->s_flags |= MS_ACTIVE;
2372 
2373 out:
2374 	return mntroot;
2375 
2376 out_err_nosb:
2377 	nfs_free_server(server);
2378 	goto out;
2379 
2380 error_splat_root:
2381 	dput(mntroot);
2382 	mntroot = ERR_PTR(error);
2383 error_splat_super:
2384 	if (server && !s->s_root)
2385 		bdi_unregister(&server->backing_dev_info);
2386 error_splat_bdi:
2387 	deactivate_locked_super(s);
2388 	goto out;
2389 }
2390 EXPORT_SYMBOL_GPL(nfs_fs_mount_common);
2391 
2392 struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
2393 	int flags, const char *dev_name, void *raw_data)
2394 {
2395 	struct nfs_mount_info mount_info = {
2396 		.fill_super = nfs_fill_super,
2397 		.set_security = nfs_set_sb_security,
2398 	};
2399 	struct dentry *mntroot = ERR_PTR(-ENOMEM);
2400 	struct nfs_subversion *nfs_mod;
2401 	int error;
2402 
2403 	mount_info.parsed = nfs_alloc_parsed_mount_data();
2404 	mount_info.mntfh = nfs_alloc_fhandle();
2405 	if (mount_info.parsed == NULL || mount_info.mntfh == NULL)
2406 		goto out;
2407 
2408 	/* Validate the mount data */
2409 	error = nfs_validate_mount_data(fs_type, raw_data, mount_info.parsed, mount_info.mntfh, dev_name);
2410 	if (error == NFS_TEXT_DATA)
2411 		error = nfs_validate_text_mount_data(raw_data, mount_info.parsed, dev_name);
2412 	if (error < 0) {
2413 		mntroot = ERR_PTR(error);
2414 		goto out;
2415 	}
2416 
2417 	nfs_mod = get_nfs_version(mount_info.parsed->version);
2418 	if (IS_ERR(nfs_mod)) {
2419 		mntroot = ERR_CAST(nfs_mod);
2420 		goto out;
2421 	}
2422 
2423 	mntroot = nfs_mod->rpc_ops->try_mount(flags, dev_name, &mount_info, nfs_mod);
2424 
2425 	put_nfs_version(nfs_mod);
2426 out:
2427 	nfs_free_parsed_mount_data(mount_info.parsed);
2428 	nfs_free_fhandle(mount_info.mntfh);
2429 	return mntroot;
2430 }
2431 EXPORT_SYMBOL_GPL(nfs_fs_mount);
2432 
2433 /*
2434  * Ensure that we unregister the bdi before kill_anon_super
2435  * releases the device name
2436  */
2437 void nfs_put_super(struct super_block *s)
2438 {
2439 	struct nfs_server *server = NFS_SB(s);
2440 
2441 	bdi_unregister(&server->backing_dev_info);
2442 }
2443 EXPORT_SYMBOL_GPL(nfs_put_super);
2444 
2445 /*
2446  * Destroy an NFS2/3 superblock
2447  */
2448 void nfs_kill_super(struct super_block *s)
2449 {
2450 	struct nfs_server *server = NFS_SB(s);
2451 
2452 	kill_anon_super(s);
2453 	nfs_fscache_release_super_cookie(s);
2454 	nfs_free_server(server);
2455 }
2456 EXPORT_SYMBOL_GPL(nfs_kill_super);
2457 
2458 /*
2459  * Clone an NFS2/3/4 server record on xdev traversal (FSID-change)
2460  */
2461 struct dentry *
2462 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2463 		const char *dev_name, void *raw_data)
2464 {
2465 	struct nfs_clone_mount *data = raw_data;
2466 	struct nfs_mount_info mount_info = {
2467 		.fill_super = nfs_clone_super,
2468 		.set_security = nfs_clone_sb_security,
2469 		.cloned = data,
2470 	};
2471 	struct nfs_server *server;
2472 	struct dentry *mntroot = ERR_PTR(-ENOMEM);
2473 	struct nfs_subversion *nfs_mod = NFS_SB(data->sb)->nfs_client->cl_nfs_mod;
2474 	int error;
2475 
2476 	dprintk("--> nfs_xdev_mount_common()\n");
2477 
2478 	mount_info.mntfh = mount_info.cloned->fh;
2479 
2480 	/* create a new volume representation */
2481 	server = nfs_mod->rpc_ops->clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
2482 	if (IS_ERR(server)) {
2483 		error = PTR_ERR(server);
2484 		goto out_err;
2485 	}
2486 
2487 	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, nfs_mod);
2488 	dprintk("<-- nfs_xdev_mount_common() = 0\n");
2489 out:
2490 	return mntroot;
2491 
2492 out_err:
2493 	dprintk("<-- nfs_xdev_mount_common() = %d [error]\n", error);
2494 	goto out;
2495 }
2496 
2497 #if IS_ENABLED(CONFIG_NFS_V4)
2498 
2499 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2500 {
2501 	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2502 			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2503 }
2504 
2505 /*
2506  * Validate NFSv4 mount options
2507  */
2508 static int nfs4_validate_mount_data(void *options,
2509 				    struct nfs_parsed_mount_data *args,
2510 				    const char *dev_name)
2511 {
2512 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2513 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2514 	char *c;
2515 
2516 	if (data == NULL)
2517 		goto out_no_data;
2518 
2519 	args->version = 4;
2520 
2521 	switch (data->version) {
2522 	case 1:
2523 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2524 			goto out_no_address;
2525 		if (data->host_addrlen == 0)
2526 			goto out_no_address;
2527 		args->nfs_server.addrlen = data->host_addrlen;
2528 		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2529 			return -EFAULT;
2530 		if (!nfs_verify_server_address(sap))
2531 			goto out_no_address;
2532 
2533 		if (data->auth_flavourlen) {
2534 			if (data->auth_flavourlen > 1)
2535 				goto out_inval_auth;
2536 			if (copy_from_user(&args->auth_flavors[0],
2537 					   data->auth_flavours,
2538 					   sizeof(args->auth_flavors[0])))
2539 				return -EFAULT;
2540 		}
2541 
2542 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2543 		if (IS_ERR(c))
2544 			return PTR_ERR(c);
2545 		args->nfs_server.hostname = c;
2546 
2547 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2548 		if (IS_ERR(c))
2549 			return PTR_ERR(c);
2550 		args->nfs_server.export_path = c;
2551 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2552 
2553 		c = strndup_user(data->client_addr.data, 16);
2554 		if (IS_ERR(c))
2555 			return PTR_ERR(c);
2556 		args->client_address = c;
2557 
2558 		/*
2559 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2560 		 * can deal with.
2561 		 */
2562 
2563 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2564 		args->rsize	= data->rsize;
2565 		args->wsize	= data->wsize;
2566 		args->timeo	= data->timeo;
2567 		args->retrans	= data->retrans;
2568 		args->acregmin	= data->acregmin;
2569 		args->acregmax	= data->acregmax;
2570 		args->acdirmin	= data->acdirmin;
2571 		args->acdirmax	= data->acdirmax;
2572 		args->nfs_server.protocol = data->proto;
2573 		nfs_validate_transport_protocol(args);
2574 
2575 		break;
2576 	default:
2577 		return NFS_TEXT_DATA;
2578 	}
2579 
2580 	return 0;
2581 
2582 out_no_data:
2583 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2584 	return -EINVAL;
2585 
2586 out_inval_auth:
2587 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2588 		 data->auth_flavourlen);
2589 	return -EINVAL;
2590 
2591 out_no_address:
2592 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2593 	return -EINVAL;
2594 }
2595 
2596 /*
2597  * NFS v4 module parameters need to stay in the
2598  * NFS client for backwards compatibility
2599  */
2600 unsigned int nfs_callback_set_tcpport;
2601 unsigned short nfs_callback_tcpport;
2602 /* Default cache timeout is 10 minutes */
2603 unsigned int nfs_idmap_cache_timeout = 600;
2604 /* Turn off NFSv4 uid/gid mapping when using AUTH_SYS */
2605 bool nfs4_disable_idmapping = true;
2606 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
2607 unsigned short send_implementation_id = 1;
2608 
2609 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
2610 EXPORT_SYMBOL_GPL(nfs_callback_tcpport);
2611 EXPORT_SYMBOL_GPL(nfs_idmap_cache_timeout);
2612 EXPORT_SYMBOL_GPL(nfs4_disable_idmapping);
2613 EXPORT_SYMBOL_GPL(max_session_slots);
2614 EXPORT_SYMBOL_GPL(send_implementation_id);
2615 
2616 #define NFS_CALLBACK_MAXPORTNR (65535U)
2617 
2618 static int param_set_portnr(const char *val, const struct kernel_param *kp)
2619 {
2620 	unsigned long num;
2621 	int ret;
2622 
2623 	if (!val)
2624 		return -EINVAL;
2625 	ret = strict_strtoul(val, 0, &num);
2626 	if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
2627 		return -EINVAL;
2628 	*((unsigned int *)kp->arg) = num;
2629 	return 0;
2630 }
2631 static struct kernel_param_ops param_ops_portnr = {
2632 	.set = param_set_portnr,
2633 	.get = param_get_uint,
2634 };
2635 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
2636 
2637 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
2638 module_param(nfs_idmap_cache_timeout, int, 0644);
2639 module_param(nfs4_disable_idmapping, bool, 0644);
2640 MODULE_PARM_DESC(nfs4_disable_idmapping,
2641 		"Turn off NFSv4 idmapping when using 'sec=sys'");
2642 module_param(max_session_slots, ushort, 0644);
2643 MODULE_PARM_DESC(max_session_slots, "Maximum number of outstanding NFSv4.1 "
2644 		"requests the client will negotiate");
2645 module_param(send_implementation_id, ushort, 0644);
2646 MODULE_PARM_DESC(send_implementation_id,
2647 		"Send implementation ID with NFSv4.1 exchange_id");
2648 #endif /* CONFIG_NFS_V4 */
2649