xref: /openbmc/linux/fs/nfs/super.c (revision ce932d0c5589e9766e089c22c66890dfc48fbd94)
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 
68 #define NFSDBG_FACILITY		NFSDBG_VFS
69 
70 #ifdef CONFIG_NFS_V3
71 #define NFS_DEFAULT_VERSION 3
72 #else
73 #define NFS_DEFAULT_VERSION 2
74 #endif
75 
76 enum {
77 	/* Mount options that take no arguments */
78 	Opt_soft, Opt_hard,
79 	Opt_posix, Opt_noposix,
80 	Opt_cto, Opt_nocto,
81 	Opt_ac, Opt_noac,
82 	Opt_lock, Opt_nolock,
83 	Opt_udp, Opt_tcp, Opt_rdma,
84 	Opt_acl, Opt_noacl,
85 	Opt_rdirplus, Opt_nordirplus,
86 	Opt_sharecache, Opt_nosharecache,
87 	Opt_resvport, Opt_noresvport,
88 	Opt_fscache, Opt_nofscache,
89 
90 	/* Mount options that take integer arguments */
91 	Opt_port,
92 	Opt_rsize, Opt_wsize, Opt_bsize,
93 	Opt_timeo, Opt_retrans,
94 	Opt_acregmin, Opt_acregmax,
95 	Opt_acdirmin, Opt_acdirmax,
96 	Opt_actimeo,
97 	Opt_namelen,
98 	Opt_mountport,
99 	Opt_mountvers,
100 	Opt_minorversion,
101 
102 	/* Mount options that take string arguments */
103 	Opt_nfsvers,
104 	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
105 	Opt_addr, Opt_mountaddr, Opt_clientaddr,
106 	Opt_lookupcache,
107 	Opt_fscache_uniq,
108 	Opt_local_lock,
109 
110 	/* Special mount options */
111 	Opt_userspace, Opt_deprecated, Opt_sloppy,
112 
113 	Opt_err
114 };
115 
116 static const match_table_t nfs_mount_option_tokens = {
117 	{ Opt_userspace, "bg" },
118 	{ Opt_userspace, "fg" },
119 	{ Opt_userspace, "retry=%s" },
120 
121 	{ Opt_sloppy, "sloppy" },
122 
123 	{ Opt_soft, "soft" },
124 	{ Opt_hard, "hard" },
125 	{ Opt_deprecated, "intr" },
126 	{ Opt_deprecated, "nointr" },
127 	{ Opt_posix, "posix" },
128 	{ Opt_noposix, "noposix" },
129 	{ Opt_cto, "cto" },
130 	{ Opt_nocto, "nocto" },
131 	{ Opt_ac, "ac" },
132 	{ Opt_noac, "noac" },
133 	{ Opt_lock, "lock" },
134 	{ Opt_nolock, "nolock" },
135 	{ Opt_udp, "udp" },
136 	{ Opt_tcp, "tcp" },
137 	{ Opt_rdma, "rdma" },
138 	{ Opt_acl, "acl" },
139 	{ Opt_noacl, "noacl" },
140 	{ Opt_rdirplus, "rdirplus" },
141 	{ Opt_nordirplus, "nordirplus" },
142 	{ Opt_sharecache, "sharecache" },
143 	{ Opt_nosharecache, "nosharecache" },
144 	{ Opt_resvport, "resvport" },
145 	{ Opt_noresvport, "noresvport" },
146 	{ Opt_fscache, "fsc" },
147 	{ Opt_nofscache, "nofsc" },
148 
149 	{ Opt_port, "port=%s" },
150 	{ Opt_rsize, "rsize=%s" },
151 	{ Opt_wsize, "wsize=%s" },
152 	{ Opt_bsize, "bsize=%s" },
153 	{ Opt_timeo, "timeo=%s" },
154 	{ Opt_retrans, "retrans=%s" },
155 	{ Opt_acregmin, "acregmin=%s" },
156 	{ Opt_acregmax, "acregmax=%s" },
157 	{ Opt_acdirmin, "acdirmin=%s" },
158 	{ Opt_acdirmax, "acdirmax=%s" },
159 	{ Opt_actimeo, "actimeo=%s" },
160 	{ Opt_namelen, "namlen=%s" },
161 	{ Opt_mountport, "mountport=%s" },
162 	{ Opt_mountvers, "mountvers=%s" },
163 	{ Opt_minorversion, "minorversion=%s" },
164 
165 	{ Opt_nfsvers, "nfsvers=%s" },
166 	{ Opt_nfsvers, "vers=%s" },
167 
168 	{ Opt_sec, "sec=%s" },
169 	{ Opt_proto, "proto=%s" },
170 	{ Opt_mountproto, "mountproto=%s" },
171 	{ Opt_addr, "addr=%s" },
172 	{ Opt_clientaddr, "clientaddr=%s" },
173 	{ Opt_mounthost, "mounthost=%s" },
174 	{ Opt_mountaddr, "mountaddr=%s" },
175 
176 	{ Opt_lookupcache, "lookupcache=%s" },
177 	{ Opt_fscache_uniq, "fsc=%s" },
178 	{ Opt_local_lock, "local_lock=%s" },
179 
180 	/* The following needs to be listed after all other options */
181 	{ Opt_nfsvers, "v%s" },
182 
183 	{ Opt_err, NULL }
184 };
185 
186 enum {
187 	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
188 
189 	Opt_xprt_err
190 };
191 
192 static const match_table_t nfs_xprt_protocol_tokens = {
193 	{ Opt_xprt_udp, "udp" },
194 	{ Opt_xprt_udp6, "udp6" },
195 	{ Opt_xprt_tcp, "tcp" },
196 	{ Opt_xprt_tcp6, "tcp6" },
197 	{ Opt_xprt_rdma, "rdma" },
198 
199 	{ Opt_xprt_err, NULL }
200 };
201 
202 enum {
203 	Opt_sec_none, Opt_sec_sys,
204 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
205 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
206 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
207 
208 	Opt_sec_err
209 };
210 
211 static const match_table_t nfs_secflavor_tokens = {
212 	{ Opt_sec_none, "none" },
213 	{ Opt_sec_none, "null" },
214 	{ Opt_sec_sys, "sys" },
215 
216 	{ Opt_sec_krb5, "krb5" },
217 	{ Opt_sec_krb5i, "krb5i" },
218 	{ Opt_sec_krb5p, "krb5p" },
219 
220 	{ Opt_sec_lkey, "lkey" },
221 	{ Opt_sec_lkeyi, "lkeyi" },
222 	{ Opt_sec_lkeyp, "lkeyp" },
223 
224 	{ Opt_sec_spkm, "spkm3" },
225 	{ Opt_sec_spkmi, "spkm3i" },
226 	{ Opt_sec_spkmp, "spkm3p" },
227 
228 	{ Opt_sec_err, NULL }
229 };
230 
231 enum {
232 	Opt_lookupcache_all, Opt_lookupcache_positive,
233 	Opt_lookupcache_none,
234 
235 	Opt_lookupcache_err
236 };
237 
238 static match_table_t nfs_lookupcache_tokens = {
239 	{ Opt_lookupcache_all, "all" },
240 	{ Opt_lookupcache_positive, "pos" },
241 	{ Opt_lookupcache_positive, "positive" },
242 	{ Opt_lookupcache_none, "none" },
243 
244 	{ Opt_lookupcache_err, NULL }
245 };
246 
247 enum {
248 	Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
249 	Opt_local_lock_none,
250 
251 	Opt_local_lock_err
252 };
253 
254 static match_table_t nfs_local_lock_tokens = {
255 	{ Opt_local_lock_all, "all" },
256 	{ Opt_local_lock_flock, "flock" },
257 	{ Opt_local_lock_posix, "posix" },
258 	{ Opt_local_lock_none, "none" },
259 
260 	{ Opt_local_lock_err, NULL }
261 };
262 
263 enum {
264 	Opt_vers_2, Opt_vers_3, Opt_vers_4, Opt_vers_4_0,
265 	Opt_vers_4_1,
266 
267 	Opt_vers_err
268 };
269 
270 static match_table_t nfs_vers_tokens = {
271 	{ Opt_vers_2, "2" },
272 	{ Opt_vers_3, "3" },
273 	{ Opt_vers_4, "4" },
274 	{ Opt_vers_4_0, "4.0" },
275 	{ Opt_vers_4_1, "4.1" },
276 
277 	{ Opt_vers_err, NULL }
278 };
279 
280 static void nfs_umount_begin(struct super_block *);
281 static int  nfs_statfs(struct dentry *, struct kstatfs *);
282 static int  nfs_show_options(struct seq_file *, struct dentry *);
283 static int  nfs_show_devname(struct seq_file *, struct dentry *);
284 static int  nfs_show_path(struct seq_file *, struct dentry *);
285 static int  nfs_show_stats(struct seq_file *, struct dentry *);
286 static struct dentry *nfs_fs_mount(struct file_system_type *,
287 		int, const char *, void *);
288 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
289 		int flags, const char *dev_name, void *raw_data);
290 static void nfs_put_super(struct super_block *);
291 static void nfs_kill_super(struct super_block *);
292 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
293 
294 static struct file_system_type nfs_fs_type = {
295 	.owner		= THIS_MODULE,
296 	.name		= "nfs",
297 	.mount		= nfs_fs_mount,
298 	.kill_sb	= nfs_kill_super,
299 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
300 };
301 
302 struct file_system_type nfs_xdev_fs_type = {
303 	.owner		= THIS_MODULE,
304 	.name		= "nfs",
305 	.mount		= nfs_xdev_mount,
306 	.kill_sb	= nfs_kill_super,
307 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
308 };
309 
310 static const struct super_operations nfs_sops = {
311 	.alloc_inode	= nfs_alloc_inode,
312 	.destroy_inode	= nfs_destroy_inode,
313 	.write_inode	= nfs_write_inode,
314 	.put_super	= nfs_put_super,
315 	.statfs		= nfs_statfs,
316 	.evict_inode	= nfs_evict_inode,
317 	.umount_begin	= nfs_umount_begin,
318 	.show_options	= nfs_show_options,
319 	.show_devname	= nfs_show_devname,
320 	.show_path	= nfs_show_path,
321 	.show_stats	= nfs_show_stats,
322 	.remount_fs	= nfs_remount,
323 };
324 
325 #ifdef CONFIG_NFS_V4
326 static int nfs4_validate_text_mount_data(void *options,
327 	struct nfs_parsed_mount_data *args, const char *dev_name);
328 static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
329 	struct nfs_parsed_mount_data *data);
330 static struct dentry *nfs4_mount(struct file_system_type *fs_type,
331 	int flags, const char *dev_name, void *raw_data);
332 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
333 	int flags, const char *dev_name, void *raw_data);
334 static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
335 	int flags, const char *dev_name, void *raw_data);
336 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
337 	int flags, const char *dev_name, void *raw_data);
338 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
339 	int flags, const char *dev_name, void *raw_data);
340 static void nfs4_kill_super(struct super_block *sb);
341 
342 static struct file_system_type nfs4_fs_type = {
343 	.owner		= THIS_MODULE,
344 	.name		= "nfs4",
345 	.mount		= nfs4_mount,
346 	.kill_sb	= nfs4_kill_super,
347 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
348 };
349 
350 static struct file_system_type nfs4_remote_fs_type = {
351 	.owner		= THIS_MODULE,
352 	.name		= "nfs4",
353 	.mount		= nfs4_remote_mount,
354 	.kill_sb	= nfs4_kill_super,
355 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
356 };
357 
358 struct file_system_type nfs4_xdev_fs_type = {
359 	.owner		= THIS_MODULE,
360 	.name		= "nfs4",
361 	.mount		= nfs4_xdev_mount,
362 	.kill_sb	= nfs4_kill_super,
363 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
364 };
365 
366 static struct file_system_type nfs4_remote_referral_fs_type = {
367 	.owner		= THIS_MODULE,
368 	.name		= "nfs4",
369 	.mount		= nfs4_remote_referral_mount,
370 	.kill_sb	= nfs4_kill_super,
371 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
372 };
373 
374 struct file_system_type nfs4_referral_fs_type = {
375 	.owner		= THIS_MODULE,
376 	.name		= "nfs4",
377 	.mount		= nfs4_referral_mount,
378 	.kill_sb	= nfs4_kill_super,
379 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
380 };
381 
382 static const struct super_operations nfs4_sops = {
383 	.alloc_inode	= nfs_alloc_inode,
384 	.destroy_inode	= nfs_destroy_inode,
385 	.write_inode	= nfs_write_inode,
386 	.put_super	= nfs_put_super,
387 	.statfs		= nfs_statfs,
388 	.evict_inode	= nfs4_evict_inode,
389 	.umount_begin	= nfs_umount_begin,
390 	.show_options	= nfs_show_options,
391 	.show_devname	= nfs_show_devname,
392 	.show_path	= nfs_show_path,
393 	.show_stats	= nfs_show_stats,
394 	.remount_fs	= nfs_remount,
395 };
396 #endif
397 
398 static struct shrinker acl_shrinker = {
399 	.shrink		= nfs_access_cache_shrinker,
400 	.seeks		= DEFAULT_SEEKS,
401 };
402 
403 /*
404  * Register the NFS filesystems
405  */
406 int __init register_nfs_fs(void)
407 {
408 	int ret;
409 
410         ret = register_filesystem(&nfs_fs_type);
411 	if (ret < 0)
412 		goto error_0;
413 
414 	ret = nfs_register_sysctl();
415 	if (ret < 0)
416 		goto error_1;
417 #ifdef CONFIG_NFS_V4
418 	ret = register_filesystem(&nfs4_fs_type);
419 	if (ret < 0)
420 		goto error_2;
421 #endif
422 	register_shrinker(&acl_shrinker);
423 	return 0;
424 
425 #ifdef CONFIG_NFS_V4
426 error_2:
427 	nfs_unregister_sysctl();
428 #endif
429 error_1:
430 	unregister_filesystem(&nfs_fs_type);
431 error_0:
432 	return ret;
433 }
434 
435 /*
436  * Unregister the NFS filesystems
437  */
438 void __exit unregister_nfs_fs(void)
439 {
440 	unregister_shrinker(&acl_shrinker);
441 #ifdef CONFIG_NFS_V4
442 	unregister_filesystem(&nfs4_fs_type);
443 #endif
444 	nfs_unregister_sysctl();
445 	unregister_filesystem(&nfs_fs_type);
446 }
447 
448 void nfs_sb_active(struct super_block *sb)
449 {
450 	struct nfs_server *server = NFS_SB(sb);
451 
452 	if (atomic_inc_return(&server->active) == 1)
453 		atomic_inc(&sb->s_active);
454 }
455 
456 void nfs_sb_deactive(struct super_block *sb)
457 {
458 	struct nfs_server *server = NFS_SB(sb);
459 
460 	if (atomic_dec_and_test(&server->active))
461 		deactivate_super(sb);
462 }
463 
464 /*
465  * Deliver file system statistics to userspace
466  */
467 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
468 {
469 	struct nfs_server *server = NFS_SB(dentry->d_sb);
470 	unsigned char blockbits;
471 	unsigned long blockres;
472 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
473 	struct nfs_fsstat res;
474 	int error = -ENOMEM;
475 
476 	res.fattr = nfs_alloc_fattr();
477 	if (res.fattr == NULL)
478 		goto out_err;
479 
480 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
481 	if (unlikely(error == -ESTALE)) {
482 		struct dentry *pd_dentry;
483 
484 		pd_dentry = dget_parent(dentry);
485 		if (pd_dentry != NULL) {
486 			nfs_zap_caches(pd_dentry->d_inode);
487 			dput(pd_dentry);
488 		}
489 	}
490 	nfs_free_fattr(res.fattr);
491 	if (error < 0)
492 		goto out_err;
493 
494 	buf->f_type = NFS_SUPER_MAGIC;
495 
496 	/*
497 	 * Current versions of glibc do not correctly handle the
498 	 * case where f_frsize != f_bsize.  Eventually we want to
499 	 * report the value of wtmult in this field.
500 	 */
501 	buf->f_frsize = dentry->d_sb->s_blocksize;
502 
503 	/*
504 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
505 	 * are reported in units of f_frsize.  Linux hasn't had
506 	 * an f_frsize field in its statfs struct until recently,
507 	 * thus historically Linux's sys_statfs reports these
508 	 * fields in units of f_bsize.
509 	 */
510 	buf->f_bsize = dentry->d_sb->s_blocksize;
511 	blockbits = dentry->d_sb->s_blocksize_bits;
512 	blockres = (1 << blockbits) - 1;
513 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
514 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
515 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
516 
517 	buf->f_files = res.tfiles;
518 	buf->f_ffree = res.afiles;
519 
520 	buf->f_namelen = server->namelen;
521 
522 	return 0;
523 
524  out_err:
525 	dprintk("%s: statfs error = %d\n", __func__, -error);
526 	return error;
527 }
528 
529 /*
530  * Map the security flavour number to a name
531  */
532 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
533 {
534 	static const struct {
535 		rpc_authflavor_t flavour;
536 		const char *str;
537 	} sec_flavours[] = {
538 		{ RPC_AUTH_NULL, "null" },
539 		{ RPC_AUTH_UNIX, "sys" },
540 		{ RPC_AUTH_GSS_KRB5, "krb5" },
541 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
542 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
543 		{ RPC_AUTH_GSS_LKEY, "lkey" },
544 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
545 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
546 		{ RPC_AUTH_GSS_SPKM, "spkm" },
547 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
548 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
549 		{ UINT_MAX, "unknown" }
550 	};
551 	int i;
552 
553 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
554 		if (sec_flavours[i].flavour == flavour)
555 			break;
556 	}
557 	return sec_flavours[i].str;
558 }
559 
560 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
561 				  int showdefaults)
562 {
563 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
564 
565 	seq_printf(m, ",mountproto=");
566 	switch (sap->sa_family) {
567 	case AF_INET:
568 		switch (nfss->mountd_protocol) {
569 		case IPPROTO_UDP:
570 			seq_printf(m, RPCBIND_NETID_UDP);
571 			break;
572 		case IPPROTO_TCP:
573 			seq_printf(m, RPCBIND_NETID_TCP);
574 			break;
575 		default:
576 			if (showdefaults)
577 				seq_printf(m, "auto");
578 		}
579 		break;
580 	case AF_INET6:
581 		switch (nfss->mountd_protocol) {
582 		case IPPROTO_UDP:
583 			seq_printf(m, RPCBIND_NETID_UDP6);
584 			break;
585 		case IPPROTO_TCP:
586 			seq_printf(m, RPCBIND_NETID_TCP6);
587 			break;
588 		default:
589 			if (showdefaults)
590 				seq_printf(m, "auto");
591 		}
592 		break;
593 	default:
594 		if (showdefaults)
595 			seq_printf(m, "auto");
596 	}
597 }
598 
599 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
600 				    int showdefaults)
601 {
602 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
603 
604 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
605 		return;
606 
607 	switch (sap->sa_family) {
608 	case AF_INET: {
609 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
610 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
611 		break;
612 	}
613 	case AF_INET6: {
614 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
615 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
616 		break;
617 	}
618 	default:
619 		if (showdefaults)
620 			seq_printf(m, ",mountaddr=unspecified");
621 	}
622 
623 	if (nfss->mountd_version || showdefaults)
624 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
625 	if ((nfss->mountd_port &&
626 		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
627 		showdefaults)
628 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
629 
630 	nfs_show_mountd_netid(m, nfss, showdefaults);
631 }
632 
633 #ifdef CONFIG_NFS_V4
634 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
635 				    int showdefaults)
636 {
637 	struct nfs_client *clp = nfss->nfs_client;
638 
639 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
640 }
641 #else
642 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
643 				    int showdefaults)
644 {
645 }
646 #endif
647 
648 static void nfs_show_nfs_version(struct seq_file *m,
649 		unsigned int version,
650 		unsigned int minorversion)
651 {
652 	seq_printf(m, ",vers=%u", version);
653 	if (version == 4)
654 		seq_printf(m, ".%u", minorversion);
655 }
656 
657 /*
658  * Describe the mount options in force on this server representation
659  */
660 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
661 				   int showdefaults)
662 {
663 	static const struct proc_nfs_info {
664 		int flag;
665 		const char *str;
666 		const char *nostr;
667 	} nfs_info[] = {
668 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
669 		{ NFS_MOUNT_POSIX, ",posix", "" },
670 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
671 		{ NFS_MOUNT_NOAC, ",noac", "" },
672 		{ NFS_MOUNT_NONLM, ",nolock", "" },
673 		{ NFS_MOUNT_NOACL, ",noacl", "" },
674 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
675 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
676 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
677 		{ 0, NULL, NULL }
678 	};
679 	const struct proc_nfs_info *nfs_infop;
680 	struct nfs_client *clp = nfss->nfs_client;
681 	u32 version = clp->rpc_ops->version;
682 	int local_flock, local_fcntl;
683 
684 	nfs_show_nfs_version(m, version, clp->cl_minorversion);
685 	seq_printf(m, ",rsize=%u", nfss->rsize);
686 	seq_printf(m, ",wsize=%u", nfss->wsize);
687 	if (nfss->bsize != 0)
688 		seq_printf(m, ",bsize=%u", nfss->bsize);
689 	seq_printf(m, ",namlen=%u", nfss->namelen);
690 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
691 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
692 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
693 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
694 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
695 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
696 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
697 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
698 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
699 		if (nfss->flags & nfs_infop->flag)
700 			seq_puts(m, nfs_infop->str);
701 		else
702 			seq_puts(m, nfs_infop->nostr);
703 	}
704 	rcu_read_lock();
705 	seq_printf(m, ",proto=%s",
706 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
707 	rcu_read_unlock();
708 	if (version == 4) {
709 		if (nfss->port != NFS_PORT)
710 			seq_printf(m, ",port=%u", nfss->port);
711 	} else
712 		if (nfss->port)
713 			seq_printf(m, ",port=%u", nfss->port);
714 
715 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
716 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
717 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
718 
719 	if (version != 4)
720 		nfs_show_mountd_options(m, nfss, showdefaults);
721 	else
722 		nfs_show_nfsv4_options(m, nfss, showdefaults);
723 
724 	if (nfss->options & NFS_OPTION_FSCACHE)
725 		seq_printf(m, ",fsc");
726 
727 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
728 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
729 			seq_printf(m, ",lookupcache=none");
730 		else
731 			seq_printf(m, ",lookupcache=pos");
732 	}
733 
734 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
735 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
736 
737 	if (!local_flock && !local_fcntl)
738 		seq_printf(m, ",local_lock=none");
739 	else if (local_flock && local_fcntl)
740 		seq_printf(m, ",local_lock=all");
741 	else if (local_flock)
742 		seq_printf(m, ",local_lock=flock");
743 	else
744 		seq_printf(m, ",local_lock=posix");
745 }
746 
747 /*
748  * Describe the mount options on this VFS mountpoint
749  */
750 static int nfs_show_options(struct seq_file *m, struct dentry *root)
751 {
752 	struct nfs_server *nfss = NFS_SB(root->d_sb);
753 
754 	nfs_show_mount_options(m, nfss, 0);
755 
756 	rcu_read_lock();
757 	seq_printf(m, ",addr=%s",
758 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
759 							RPC_DISPLAY_ADDR));
760 	rcu_read_unlock();
761 
762 	return 0;
763 }
764 
765 #ifdef CONFIG_NFS_V4
766 #ifdef CONFIG_NFS_V4_1
767 static void show_sessions(struct seq_file *m, struct nfs_server *server)
768 {
769 	if (nfs4_has_session(server->nfs_client))
770 		seq_printf(m, ",sessions");
771 }
772 #else
773 static void show_sessions(struct seq_file *m, struct nfs_server *server) {}
774 #endif
775 #endif
776 
777 #ifdef CONFIG_NFS_V4_1
778 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
779 {
780 	seq_printf(m, ",pnfs=");
781 	if (server->pnfs_curr_ld)
782 		seq_printf(m, "%s", server->pnfs_curr_ld->name);
783 	else
784 		seq_printf(m, "not configured");
785 }
786 
787 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
788 {
789 	if (nfss->nfs_client && nfss->nfs_client->impl_id) {
790 		struct nfs41_impl_id *impl_id = nfss->nfs_client->impl_id;
791 		seq_printf(m, "\n\timpl_id:\tname='%s',domain='%s',"
792 			   "date='%llu,%u'",
793 			   impl_id->name, impl_id->domain,
794 			   impl_id->date.seconds, impl_id->date.nseconds);
795 	}
796 }
797 #else
798 #ifdef CONFIG_NFS_V4
799 static void show_pnfs(struct seq_file *m, struct nfs_server *server)
800 {
801 }
802 #endif
803 static void show_implementation_id(struct seq_file *m, struct nfs_server *nfss)
804 {
805 }
806 #endif
807 
808 static int nfs_show_devname(struct seq_file *m, struct dentry *root)
809 {
810 	char *page = (char *) __get_free_page(GFP_KERNEL);
811 	char *devname, *dummy;
812 	int err = 0;
813 	if (!page)
814 		return -ENOMEM;
815 	devname = nfs_path(&dummy, root, page, PAGE_SIZE);
816 	if (IS_ERR(devname))
817 		err = PTR_ERR(devname);
818 	else
819 		seq_escape(m, devname, " \t\n\\");
820 	free_page((unsigned long)page);
821 	return err;
822 }
823 
824 static int nfs_show_path(struct seq_file *m, struct dentry *dentry)
825 {
826 	seq_puts(m, "/");
827 	return 0;
828 }
829 
830 /*
831  * Present statistical information for this VFS mountpoint
832  */
833 static int nfs_show_stats(struct seq_file *m, struct dentry *root)
834 {
835 	int i, cpu;
836 	struct nfs_server *nfss = NFS_SB(root->d_sb);
837 	struct rpc_auth *auth = nfss->client->cl_auth;
838 	struct nfs_iostats totals = { };
839 
840 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
841 
842 	/*
843 	 * Display all mount option settings
844 	 */
845 	seq_printf(m, "\n\topts:\t");
846 	seq_puts(m, root->d_sb->s_flags & MS_RDONLY ? "ro" : "rw");
847 	seq_puts(m, root->d_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
848 	seq_puts(m, root->d_sb->s_flags & MS_NOATIME ? ",noatime" : "");
849 	seq_puts(m, root->d_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
850 	nfs_show_mount_options(m, nfss, 1);
851 
852 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
853 
854 	show_implementation_id(m, nfss);
855 
856 	seq_printf(m, "\n\tcaps:\t");
857 	seq_printf(m, "caps=0x%x", nfss->caps);
858 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
859 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
860 	seq_printf(m, ",bsize=%u", nfss->bsize);
861 	seq_printf(m, ",namlen=%u", nfss->namelen);
862 
863 #ifdef CONFIG_NFS_V4
864 	if (nfss->nfs_client->rpc_ops->version == 4) {
865 		seq_printf(m, "\n\tnfsv4:\t");
866 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
867 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
868 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
869 		show_sessions(m, nfss);
870 		show_pnfs(m, nfss);
871 	}
872 #endif
873 
874 	/*
875 	 * Display security flavor in effect for this mount
876 	 */
877 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
878 	if (auth->au_flavor)
879 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
880 
881 	/*
882 	 * Display superblock I/O counters
883 	 */
884 	for_each_possible_cpu(cpu) {
885 		struct nfs_iostats *stats;
886 
887 		preempt_disable();
888 		stats = per_cpu_ptr(nfss->io_stats, cpu);
889 
890 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
891 			totals.events[i] += stats->events[i];
892 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
893 			totals.bytes[i] += stats->bytes[i];
894 #ifdef CONFIG_NFS_FSCACHE
895 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
896 			totals.fscache[i] += stats->fscache[i];
897 #endif
898 
899 		preempt_enable();
900 	}
901 
902 	seq_printf(m, "\n\tevents:\t");
903 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
904 		seq_printf(m, "%lu ", totals.events[i]);
905 	seq_printf(m, "\n\tbytes:\t");
906 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
907 		seq_printf(m, "%Lu ", totals.bytes[i]);
908 #ifdef CONFIG_NFS_FSCACHE
909 	if (nfss->options & NFS_OPTION_FSCACHE) {
910 		seq_printf(m, "\n\tfsc:\t");
911 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
912 			seq_printf(m, "%Lu ", totals.bytes[i]);
913 	}
914 #endif
915 	seq_printf(m, "\n");
916 
917 	rpc_print_iostats(m, nfss->client);
918 
919 	return 0;
920 }
921 
922 /*
923  * Begin unmount by attempting to remove all automounted mountpoints we added
924  * in response to xdev traversals and referrals
925  */
926 static void nfs_umount_begin(struct super_block *sb)
927 {
928 	struct nfs_server *server;
929 	struct rpc_clnt *rpc;
930 
931 	server = NFS_SB(sb);
932 	/* -EIO all pending I/O */
933 	rpc = server->client_acl;
934 	if (!IS_ERR(rpc))
935 		rpc_killall_tasks(rpc);
936 	rpc = server->client;
937 	if (!IS_ERR(rpc))
938 		rpc_killall_tasks(rpc);
939 }
940 
941 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
942 {
943 	struct nfs_parsed_mount_data *data;
944 
945 	data = kzalloc(sizeof(*data), GFP_KERNEL);
946 	if (data) {
947 		data->acregmin		= NFS_DEF_ACREGMIN;
948 		data->acregmax		= NFS_DEF_ACREGMAX;
949 		data->acdirmin		= NFS_DEF_ACDIRMIN;
950 		data->acdirmax		= NFS_DEF_ACDIRMAX;
951 		data->mount_server.port	= NFS_UNSPEC_PORT;
952 		data->nfs_server.port	= NFS_UNSPEC_PORT;
953 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
954 		data->auth_flavors[0]	= RPC_AUTH_UNIX;
955 		data->auth_flavor_len	= 1;
956 		data->version		= version;
957 		data->minorversion	= 0;
958 		data->net		= current->nsproxy->net_ns;
959 		security_init_mnt_opts(&data->lsm_opts);
960 	}
961 	return data;
962 }
963 
964 static void nfs_free_parsed_mount_data(struct nfs_parsed_mount_data *data)
965 {
966 	if (data) {
967 		kfree(data->client_address);
968 		kfree(data->mount_server.hostname);
969 		kfree(data->nfs_server.export_path);
970 		kfree(data->nfs_server.hostname);
971 		kfree(data->fscache_uniq);
972 		security_free_mnt_opts(&data->lsm_opts);
973 		kfree(data);
974 	}
975 }
976 
977 /*
978  * Sanity-check a server address provided by the mount command.
979  *
980  * Address family must be initialized, and address must not be
981  * the ANY address for that family.
982  */
983 static int nfs_verify_server_address(struct sockaddr *addr)
984 {
985 	switch (addr->sa_family) {
986 	case AF_INET: {
987 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
988 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
989 	}
990 	case AF_INET6: {
991 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
992 		return !ipv6_addr_any(sa);
993 	}
994 	}
995 
996 	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
997 	return 0;
998 }
999 
1000 /*
1001  * Select between a default port value and a user-specified port value.
1002  * If a zero value is set, then autobind will be used.
1003  */
1004 static void nfs_set_port(struct sockaddr *sap, int *port,
1005 				 const unsigned short default_port)
1006 {
1007 	if (*port == NFS_UNSPEC_PORT)
1008 		*port = default_port;
1009 
1010 	rpc_set_port(sap, *port);
1011 }
1012 
1013 /*
1014  * Sanity check the NFS transport protocol.
1015  *
1016  */
1017 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
1018 {
1019 	switch (mnt->nfs_server.protocol) {
1020 	case XPRT_TRANSPORT_UDP:
1021 	case XPRT_TRANSPORT_TCP:
1022 	case XPRT_TRANSPORT_RDMA:
1023 		break;
1024 	default:
1025 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1026 	}
1027 }
1028 
1029 /*
1030  * For text based NFSv2/v3 mounts, the mount protocol transport default
1031  * settings should depend upon the specified NFS transport.
1032  */
1033 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
1034 {
1035 	nfs_validate_transport_protocol(mnt);
1036 
1037 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
1038 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
1039 			return;
1040 	switch (mnt->nfs_server.protocol) {
1041 	case XPRT_TRANSPORT_UDP:
1042 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1043 		break;
1044 	case XPRT_TRANSPORT_TCP:
1045 	case XPRT_TRANSPORT_RDMA:
1046 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1047 	}
1048 }
1049 
1050 /*
1051  * Parse the value of the 'sec=' option.
1052  */
1053 static int nfs_parse_security_flavors(char *value,
1054 				      struct nfs_parsed_mount_data *mnt)
1055 {
1056 	substring_t args[MAX_OPT_ARGS];
1057 
1058 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
1059 
1060 	switch (match_token(value, nfs_secflavor_tokens, args)) {
1061 	case Opt_sec_none:
1062 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
1063 		break;
1064 	case Opt_sec_sys:
1065 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
1066 		break;
1067 	case Opt_sec_krb5:
1068 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
1069 		break;
1070 	case Opt_sec_krb5i:
1071 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
1072 		break;
1073 	case Opt_sec_krb5p:
1074 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
1075 		break;
1076 	case Opt_sec_lkey:
1077 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
1078 		break;
1079 	case Opt_sec_lkeyi:
1080 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
1081 		break;
1082 	case Opt_sec_lkeyp:
1083 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
1084 		break;
1085 	case Opt_sec_spkm:
1086 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
1087 		break;
1088 	case Opt_sec_spkmi:
1089 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
1090 		break;
1091 	case Opt_sec_spkmp:
1092 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
1093 		break;
1094 	default:
1095 		return 0;
1096 	}
1097 
1098 	mnt->flags |= NFS_MOUNT_SECFLAVOUR;
1099 	mnt->auth_flavor_len = 1;
1100 	return 1;
1101 }
1102 
1103 static int nfs_parse_version_string(char *string,
1104 		struct nfs_parsed_mount_data *mnt,
1105 		substring_t *args)
1106 {
1107 	mnt->flags &= ~NFS_MOUNT_VER3;
1108 	switch (match_token(string, nfs_vers_tokens, args)) {
1109 	case Opt_vers_2:
1110 		mnt->version = 2;
1111 		break;
1112 	case Opt_vers_3:
1113 		mnt->flags |= NFS_MOUNT_VER3;
1114 		mnt->version = 3;
1115 		break;
1116 	case Opt_vers_4:
1117 		/* Backward compatibility option. In future,
1118 		 * the mount program should always supply
1119 		 * a NFSv4 minor version number.
1120 		 */
1121 		mnt->version = 4;
1122 		break;
1123 	case Opt_vers_4_0:
1124 		mnt->version = 4;
1125 		mnt->minorversion = 0;
1126 		break;
1127 	case Opt_vers_4_1:
1128 		mnt->version = 4;
1129 		mnt->minorversion = 1;
1130 		break;
1131 	default:
1132 		return 0;
1133 	}
1134 	return 1;
1135 }
1136 
1137 static int nfs_get_option_str(substring_t args[], char **option)
1138 {
1139 	kfree(*option);
1140 	*option = match_strdup(args);
1141 	return !option;
1142 }
1143 
1144 static int nfs_get_option_ul(substring_t args[], unsigned long *option)
1145 {
1146 	int rc;
1147 	char *string;
1148 
1149 	string = match_strdup(args);
1150 	if (string == NULL)
1151 		return -ENOMEM;
1152 	rc = strict_strtoul(string, 10, option);
1153 	kfree(string);
1154 
1155 	return rc;
1156 }
1157 
1158 /*
1159  * Error-check and convert a string of mount options from user space into
1160  * a data structure.  The whole mount string is processed; bad options are
1161  * skipped as they are encountered.  If there were no errors, return 1;
1162  * otherwise return 0 (zero).
1163  */
1164 static int nfs_parse_mount_options(char *raw,
1165 				   struct nfs_parsed_mount_data *mnt)
1166 {
1167 	char *p, *string, *secdata;
1168 	int rc, sloppy = 0, invalid_option = 0;
1169 	unsigned short protofamily = AF_UNSPEC;
1170 	unsigned short mountfamily = AF_UNSPEC;
1171 
1172 	if (!raw) {
1173 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
1174 		return 1;
1175 	}
1176 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
1177 
1178 	secdata = alloc_secdata();
1179 	if (!secdata)
1180 		goto out_nomem;
1181 
1182 	rc = security_sb_copy_data(raw, secdata);
1183 	if (rc)
1184 		goto out_security_failure;
1185 
1186 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1187 	if (rc)
1188 		goto out_security_failure;
1189 
1190 	free_secdata(secdata);
1191 
1192 	while ((p = strsep(&raw, ",")) != NULL) {
1193 		substring_t args[MAX_OPT_ARGS];
1194 		unsigned long option;
1195 		int token;
1196 
1197 		if (!*p)
1198 			continue;
1199 
1200 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1201 
1202 		token = match_token(p, nfs_mount_option_tokens, args);
1203 		switch (token) {
1204 
1205 		/*
1206 		 * boolean options:  foo/nofoo
1207 		 */
1208 		case Opt_soft:
1209 			mnt->flags |= NFS_MOUNT_SOFT;
1210 			break;
1211 		case Opt_hard:
1212 			mnt->flags &= ~NFS_MOUNT_SOFT;
1213 			break;
1214 		case Opt_posix:
1215 			mnt->flags |= NFS_MOUNT_POSIX;
1216 			break;
1217 		case Opt_noposix:
1218 			mnt->flags &= ~NFS_MOUNT_POSIX;
1219 			break;
1220 		case Opt_cto:
1221 			mnt->flags &= ~NFS_MOUNT_NOCTO;
1222 			break;
1223 		case Opt_nocto:
1224 			mnt->flags |= NFS_MOUNT_NOCTO;
1225 			break;
1226 		case Opt_ac:
1227 			mnt->flags &= ~NFS_MOUNT_NOAC;
1228 			break;
1229 		case Opt_noac:
1230 			mnt->flags |= NFS_MOUNT_NOAC;
1231 			break;
1232 		case Opt_lock:
1233 			mnt->flags &= ~NFS_MOUNT_NONLM;
1234 			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1235 					NFS_MOUNT_LOCAL_FCNTL);
1236 			break;
1237 		case Opt_nolock:
1238 			mnt->flags |= NFS_MOUNT_NONLM;
1239 			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1240 				       NFS_MOUNT_LOCAL_FCNTL);
1241 			break;
1242 		case Opt_udp:
1243 			mnt->flags &= ~NFS_MOUNT_TCP;
1244 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1245 			break;
1246 		case Opt_tcp:
1247 			mnt->flags |= NFS_MOUNT_TCP;
1248 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1249 			break;
1250 		case Opt_rdma:
1251 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1252 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1253 			xprt_load_transport(p);
1254 			break;
1255 		case Opt_acl:
1256 			mnt->flags &= ~NFS_MOUNT_NOACL;
1257 			break;
1258 		case Opt_noacl:
1259 			mnt->flags |= NFS_MOUNT_NOACL;
1260 			break;
1261 		case Opt_rdirplus:
1262 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1263 			break;
1264 		case Opt_nordirplus:
1265 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1266 			break;
1267 		case Opt_sharecache:
1268 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1269 			break;
1270 		case Opt_nosharecache:
1271 			mnt->flags |= NFS_MOUNT_UNSHARED;
1272 			break;
1273 		case Opt_resvport:
1274 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1275 			break;
1276 		case Opt_noresvport:
1277 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1278 			break;
1279 		case Opt_fscache:
1280 			mnt->options |= NFS_OPTION_FSCACHE;
1281 			kfree(mnt->fscache_uniq);
1282 			mnt->fscache_uniq = NULL;
1283 			break;
1284 		case Opt_nofscache:
1285 			mnt->options &= ~NFS_OPTION_FSCACHE;
1286 			kfree(mnt->fscache_uniq);
1287 			mnt->fscache_uniq = NULL;
1288 			break;
1289 
1290 		/*
1291 		 * options that take numeric values
1292 		 */
1293 		case Opt_port:
1294 			if (nfs_get_option_ul(args, &option) ||
1295 			    option > USHRT_MAX)
1296 				goto out_invalid_value;
1297 			mnt->nfs_server.port = option;
1298 			break;
1299 		case Opt_rsize:
1300 			if (nfs_get_option_ul(args, &option))
1301 				goto out_invalid_value;
1302 			mnt->rsize = option;
1303 			break;
1304 		case Opt_wsize:
1305 			if (nfs_get_option_ul(args, &option))
1306 				goto out_invalid_value;
1307 			mnt->wsize = option;
1308 			break;
1309 		case Opt_bsize:
1310 			if (nfs_get_option_ul(args, &option))
1311 				goto out_invalid_value;
1312 			mnt->bsize = option;
1313 			break;
1314 		case Opt_timeo:
1315 			if (nfs_get_option_ul(args, &option) || option == 0)
1316 				goto out_invalid_value;
1317 			mnt->timeo = option;
1318 			break;
1319 		case Opt_retrans:
1320 			if (nfs_get_option_ul(args, &option) || option == 0)
1321 				goto out_invalid_value;
1322 			mnt->retrans = option;
1323 			break;
1324 		case Opt_acregmin:
1325 			if (nfs_get_option_ul(args, &option))
1326 				goto out_invalid_value;
1327 			mnt->acregmin = option;
1328 			break;
1329 		case Opt_acregmax:
1330 			if (nfs_get_option_ul(args, &option))
1331 				goto out_invalid_value;
1332 			mnt->acregmax = option;
1333 			break;
1334 		case Opt_acdirmin:
1335 			if (nfs_get_option_ul(args, &option))
1336 				goto out_invalid_value;
1337 			mnt->acdirmin = option;
1338 			break;
1339 		case Opt_acdirmax:
1340 			if (nfs_get_option_ul(args, &option))
1341 				goto out_invalid_value;
1342 			mnt->acdirmax = option;
1343 			break;
1344 		case Opt_actimeo:
1345 			if (nfs_get_option_ul(args, &option))
1346 				goto out_invalid_value;
1347 			mnt->acregmin = mnt->acregmax =
1348 			mnt->acdirmin = mnt->acdirmax = option;
1349 			break;
1350 		case Opt_namelen:
1351 			if (nfs_get_option_ul(args, &option))
1352 				goto out_invalid_value;
1353 			mnt->namlen = option;
1354 			break;
1355 		case Opt_mountport:
1356 			if (nfs_get_option_ul(args, &option) ||
1357 			    option > USHRT_MAX)
1358 				goto out_invalid_value;
1359 			mnt->mount_server.port = option;
1360 			break;
1361 		case Opt_mountvers:
1362 			if (nfs_get_option_ul(args, &option) ||
1363 			    option < NFS_MNT_VERSION ||
1364 			    option > NFS_MNT3_VERSION)
1365 				goto out_invalid_value;
1366 			mnt->mount_server.version = option;
1367 			break;
1368 		case Opt_minorversion:
1369 			if (nfs_get_option_ul(args, &option))
1370 				goto out_invalid_value;
1371 			if (option > NFS4_MAX_MINOR_VERSION)
1372 				goto out_invalid_value;
1373 			mnt->minorversion = option;
1374 			break;
1375 
1376 		/*
1377 		 * options that take text values
1378 		 */
1379 		case Opt_nfsvers:
1380 			string = match_strdup(args);
1381 			if (string == NULL)
1382 				goto out_nomem;
1383 			rc = nfs_parse_version_string(string, mnt, args);
1384 			kfree(string);
1385 			if (!rc)
1386 				goto out_invalid_value;
1387 			break;
1388 		case Opt_sec:
1389 			string = match_strdup(args);
1390 			if (string == NULL)
1391 				goto out_nomem;
1392 			rc = nfs_parse_security_flavors(string, mnt);
1393 			kfree(string);
1394 			if (!rc) {
1395 				dfprintk(MOUNT, "NFS:   unrecognized "
1396 						"security flavor\n");
1397 				return 0;
1398 			}
1399 			break;
1400 		case Opt_proto:
1401 			string = match_strdup(args);
1402 			if (string == NULL)
1403 				goto out_nomem;
1404 			token = match_token(string,
1405 					    nfs_xprt_protocol_tokens, args);
1406 
1407 			protofamily = AF_INET;
1408 			switch (token) {
1409 			case Opt_xprt_udp6:
1410 				protofamily = AF_INET6;
1411 			case Opt_xprt_udp:
1412 				mnt->flags &= ~NFS_MOUNT_TCP;
1413 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1414 				break;
1415 			case Opt_xprt_tcp6:
1416 				protofamily = AF_INET6;
1417 			case Opt_xprt_tcp:
1418 				mnt->flags |= NFS_MOUNT_TCP;
1419 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1420 				break;
1421 			case Opt_xprt_rdma:
1422 				/* vector side protocols to TCP */
1423 				mnt->flags |= NFS_MOUNT_TCP;
1424 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1425 				xprt_load_transport(string);
1426 				break;
1427 			default:
1428 				dfprintk(MOUNT, "NFS:   unrecognized "
1429 						"transport protocol\n");
1430 				kfree(string);
1431 				return 0;
1432 			}
1433 			kfree(string);
1434 			break;
1435 		case Opt_mountproto:
1436 			string = match_strdup(args);
1437 			if (string == NULL)
1438 				goto out_nomem;
1439 			token = match_token(string,
1440 					    nfs_xprt_protocol_tokens, args);
1441 			kfree(string);
1442 
1443 			mountfamily = AF_INET;
1444 			switch (token) {
1445 			case Opt_xprt_udp6:
1446 				mountfamily = AF_INET6;
1447 			case Opt_xprt_udp:
1448 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1449 				break;
1450 			case Opt_xprt_tcp6:
1451 				mountfamily = AF_INET6;
1452 			case Opt_xprt_tcp:
1453 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1454 				break;
1455 			case Opt_xprt_rdma: /* not used for side protocols */
1456 			default:
1457 				dfprintk(MOUNT, "NFS:   unrecognized "
1458 						"transport protocol\n");
1459 				return 0;
1460 			}
1461 			break;
1462 		case Opt_addr:
1463 			string = match_strdup(args);
1464 			if (string == NULL)
1465 				goto out_nomem;
1466 			mnt->nfs_server.addrlen =
1467 				rpc_pton(mnt->net, string, strlen(string),
1468 					(struct sockaddr *)
1469 					&mnt->nfs_server.address,
1470 					sizeof(mnt->nfs_server.address));
1471 			kfree(string);
1472 			if (mnt->nfs_server.addrlen == 0)
1473 				goto out_invalid_address;
1474 			break;
1475 		case Opt_clientaddr:
1476 			if (nfs_get_option_str(args, &mnt->client_address))
1477 				goto out_nomem;
1478 			break;
1479 		case Opt_mounthost:
1480 			if (nfs_get_option_str(args,
1481 					       &mnt->mount_server.hostname))
1482 				goto out_nomem;
1483 			break;
1484 		case Opt_mountaddr:
1485 			string = match_strdup(args);
1486 			if (string == NULL)
1487 				goto out_nomem;
1488 			mnt->mount_server.addrlen =
1489 				rpc_pton(mnt->net, string, strlen(string),
1490 					(struct sockaddr *)
1491 					&mnt->mount_server.address,
1492 					sizeof(mnt->mount_server.address));
1493 			kfree(string);
1494 			if (mnt->mount_server.addrlen == 0)
1495 				goto out_invalid_address;
1496 			break;
1497 		case Opt_lookupcache:
1498 			string = match_strdup(args);
1499 			if (string == NULL)
1500 				goto out_nomem;
1501 			token = match_token(string,
1502 					nfs_lookupcache_tokens, args);
1503 			kfree(string);
1504 			switch (token) {
1505 				case Opt_lookupcache_all:
1506 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1507 					break;
1508 				case Opt_lookupcache_positive:
1509 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1510 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1511 					break;
1512 				case Opt_lookupcache_none:
1513 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1514 					break;
1515 				default:
1516 					dfprintk(MOUNT, "NFS:   invalid "
1517 							"lookupcache argument\n");
1518 					return 0;
1519 			};
1520 			break;
1521 		case Opt_fscache_uniq:
1522 			if (nfs_get_option_str(args, &mnt->fscache_uniq))
1523 				goto out_nomem;
1524 			mnt->options |= NFS_OPTION_FSCACHE;
1525 			break;
1526 		case Opt_local_lock:
1527 			string = match_strdup(args);
1528 			if (string == NULL)
1529 				goto out_nomem;
1530 			token = match_token(string, nfs_local_lock_tokens,
1531 					args);
1532 			kfree(string);
1533 			switch (token) {
1534 			case Opt_local_lock_all:
1535 				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1536 					       NFS_MOUNT_LOCAL_FCNTL);
1537 				break;
1538 			case Opt_local_lock_flock:
1539 				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1540 				break;
1541 			case Opt_local_lock_posix:
1542 				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1543 				break;
1544 			case Opt_local_lock_none:
1545 				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1546 						NFS_MOUNT_LOCAL_FCNTL);
1547 				break;
1548 			default:
1549 				dfprintk(MOUNT, "NFS:	invalid	"
1550 						"local_lock argument\n");
1551 				return 0;
1552 			};
1553 			break;
1554 
1555 		/*
1556 		 * Special options
1557 		 */
1558 		case Opt_sloppy:
1559 			sloppy = 1;
1560 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1561 			break;
1562 		case Opt_userspace:
1563 		case Opt_deprecated:
1564 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1565 					"'%s'\n", p);
1566 			break;
1567 
1568 		default:
1569 			invalid_option = 1;
1570 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1571 					"'%s'\n", p);
1572 		}
1573 	}
1574 
1575 	if (!sloppy && invalid_option)
1576 		return 0;
1577 
1578 	if (mnt->minorversion && mnt->version != 4)
1579 		goto out_minorversion_mismatch;
1580 
1581 	/*
1582 	 * verify that any proto=/mountproto= options match the address
1583 	 * familiies in the addr=/mountaddr= options.
1584 	 */
1585 	if (protofamily != AF_UNSPEC &&
1586 	    protofamily != mnt->nfs_server.address.ss_family)
1587 		goto out_proto_mismatch;
1588 
1589 	if (mountfamily != AF_UNSPEC) {
1590 		if (mnt->mount_server.addrlen) {
1591 			if (mountfamily != mnt->mount_server.address.ss_family)
1592 				goto out_mountproto_mismatch;
1593 		} else {
1594 			if (mountfamily != mnt->nfs_server.address.ss_family)
1595 				goto out_mountproto_mismatch;
1596 		}
1597 	}
1598 
1599 	return 1;
1600 
1601 out_mountproto_mismatch:
1602 	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1603 			 "option\n");
1604 	return 0;
1605 out_proto_mismatch:
1606 	printk(KERN_INFO "NFS: server address does not match proto= option\n");
1607 	return 0;
1608 out_invalid_address:
1609 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1610 	return 0;
1611 out_invalid_value:
1612 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1613 	return 0;
1614 out_minorversion_mismatch:
1615 	printk(KERN_INFO "NFS: mount option vers=%u does not support "
1616 			 "minorversion=%u\n", mnt->version, mnt->minorversion);
1617 	return 0;
1618 out_nomem:
1619 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1620 	return 0;
1621 out_security_failure:
1622 	free_secdata(secdata);
1623 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1624 	return 0;
1625 }
1626 
1627 /*
1628  * Match the requested auth flavors with the list returned by
1629  * the server.  Returns zero and sets the mount's authentication
1630  * flavor on success; returns -EACCES if server does not support
1631  * the requested flavor.
1632  */
1633 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1634 			     struct nfs_mount_request *request)
1635 {
1636 	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1637 
1638 	/*
1639 	 * Certain releases of Linux's mountd return an empty
1640 	 * flavor list.  To prevent behavioral regression with
1641 	 * these servers (ie. rejecting mounts that used to
1642 	 * succeed), revert to pre-2.6.32 behavior (no checking)
1643 	 * if the returned flavor list is empty.
1644 	 */
1645 	if (server_authlist_len == 0)
1646 		return 0;
1647 
1648 	/*
1649 	 * We avoid sophisticated negotiating here, as there are
1650 	 * plenty of cases where we can get it wrong, providing
1651 	 * either too little or too much security.
1652 	 *
1653 	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
1654 	 * flavor listed first.  However, some servers list
1655 	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1656 	 * preferred default, in args->auth_flavors[0] if user
1657 	 * didn't specify sec= mount option.
1658 	 */
1659 	for (i = 0; i < args->auth_flavor_len; i++)
1660 		for (j = 0; j < server_authlist_len; j++)
1661 			if (args->auth_flavors[i] == request->auth_flavs[j]) {
1662 				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1663 					request->auth_flavs[j]);
1664 				args->auth_flavors[0] = request->auth_flavs[j];
1665 				return 0;
1666 			}
1667 
1668 	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1669 	nfs_umount(request);
1670 	return -EACCES;
1671 }
1672 
1673 /*
1674  * Use the remote server's MOUNT service to request the NFS file handle
1675  * corresponding to the provided path.
1676  */
1677 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1678 			 struct nfs_fh *root_fh)
1679 {
1680 	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1681 	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1682 	struct nfs_mount_request request = {
1683 		.sap		= (struct sockaddr *)
1684 						&args->mount_server.address,
1685 		.dirpath	= args->nfs_server.export_path,
1686 		.protocol	= args->mount_server.protocol,
1687 		.fh		= root_fh,
1688 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1689 		.auth_flav_len	= &server_authlist_len,
1690 		.auth_flavs	= server_authlist,
1691 		.net		= args->net,
1692 	};
1693 	int status;
1694 
1695 	if (args->mount_server.version == 0) {
1696 		switch (args->version) {
1697 			default:
1698 				args->mount_server.version = NFS_MNT3_VERSION;
1699 				break;
1700 			case 2:
1701 				args->mount_server.version = NFS_MNT_VERSION;
1702 		}
1703 	}
1704 	request.version = args->mount_server.version;
1705 
1706 	if (args->mount_server.hostname)
1707 		request.hostname = args->mount_server.hostname;
1708 	else
1709 		request.hostname = args->nfs_server.hostname;
1710 
1711 	/*
1712 	 * Construct the mount server's address.
1713 	 */
1714 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1715 		memcpy(request.sap, &args->nfs_server.address,
1716 		       args->nfs_server.addrlen);
1717 		args->mount_server.addrlen = args->nfs_server.addrlen;
1718 	}
1719 	request.salen = args->mount_server.addrlen;
1720 	nfs_set_port(request.sap, &args->mount_server.port, 0);
1721 
1722 	/*
1723 	 * Now ask the mount server to map our export path
1724 	 * to a file handle.
1725 	 */
1726 	status = nfs_mount(&request);
1727 	if (status != 0) {
1728 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1729 				request.hostname, status);
1730 		return status;
1731 	}
1732 
1733 	/*
1734 	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
1735 	 */
1736 	if (args->mount_server.version != NFS_MNT3_VERSION)
1737 		return 0;
1738 	return nfs_walk_authlist(args, &request);
1739 }
1740 
1741 /*
1742  * Split "dev_name" into "hostname:export_path".
1743  *
1744  * The leftmost colon demarks the split between the server's hostname
1745  * and the export path.  If the hostname starts with a left square
1746  * bracket, then it may contain colons.
1747  *
1748  * Note: caller frees hostname and export path, even on error.
1749  */
1750 static int nfs_parse_devname(const char *dev_name,
1751 			     char **hostname, size_t maxnamlen,
1752 			     char **export_path, size_t maxpathlen)
1753 {
1754 	size_t len;
1755 	char *end;
1756 
1757 	/* Is the host name protected with square brakcets? */
1758 	if (*dev_name == '[') {
1759 		end = strchr(++dev_name, ']');
1760 		if (end == NULL || end[1] != ':')
1761 			goto out_bad_devname;
1762 
1763 		len = end - dev_name;
1764 		end++;
1765 	} else {
1766 		char *comma;
1767 
1768 		end = strchr(dev_name, ':');
1769 		if (end == NULL)
1770 			goto out_bad_devname;
1771 		len = end - dev_name;
1772 
1773 		/* kill possible hostname list: not supported */
1774 		comma = strchr(dev_name, ',');
1775 		if (comma != NULL && comma < end)
1776 			*comma = 0;
1777 	}
1778 
1779 	if (len > maxnamlen)
1780 		goto out_hostname;
1781 
1782 	/* N.B. caller will free nfs_server.hostname in all cases */
1783 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1784 	if (*hostname == NULL)
1785 		goto out_nomem;
1786 	len = strlen(++end);
1787 	if (len > maxpathlen)
1788 		goto out_path;
1789 	*export_path = kstrndup(end, len, GFP_KERNEL);
1790 	if (!*export_path)
1791 		goto out_nomem;
1792 
1793 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1794 	return 0;
1795 
1796 out_bad_devname:
1797 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1798 	return -EINVAL;
1799 
1800 out_nomem:
1801 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1802 	return -ENOMEM;
1803 
1804 out_hostname:
1805 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1806 	return -ENAMETOOLONG;
1807 
1808 out_path:
1809 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1810 	return -ENAMETOOLONG;
1811 }
1812 
1813 /*
1814  * Validate the NFS2/NFS3 mount data
1815  * - fills in the mount root filehandle
1816  *
1817  * For option strings, user space handles the following behaviors:
1818  *
1819  * + DNS: mapping server host name to IP address ("addr=" option)
1820  *
1821  * + failure mode: how to behave if a mount request can't be handled
1822  *   immediately ("fg/bg" option)
1823  *
1824  * + retry: how often to retry a mount request ("retry=" option)
1825  *
1826  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1827  *   mountproto=tcp after mountproto=udp, and so on
1828  */
1829 static int nfs_validate_mount_data(void *options,
1830 				   struct nfs_parsed_mount_data *args,
1831 				   struct nfs_fh *mntfh,
1832 				   const char *dev_name)
1833 {
1834 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1835 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1836 
1837 	if (data == NULL)
1838 		goto out_no_data;
1839 
1840 	switch (data->version) {
1841 	case 1:
1842 		data->namlen = 0;
1843 	case 2:
1844 		data->bsize = 0;
1845 	case 3:
1846 		if (data->flags & NFS_MOUNT_VER3)
1847 			goto out_no_v3;
1848 		data->root.size = NFS2_FHSIZE;
1849 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1850 	case 4:
1851 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1852 			goto out_no_sec;
1853 	case 5:
1854 		memset(data->context, 0, sizeof(data->context));
1855 	case 6:
1856 		if (data->flags & NFS_MOUNT_VER3) {
1857 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1858 				goto out_invalid_fh;
1859 			mntfh->size = data->root.size;
1860 			args->version = 3;
1861 		} else {
1862 			mntfh->size = NFS2_FHSIZE;
1863 			args->version = 2;
1864 		}
1865 
1866 
1867 		memcpy(mntfh->data, data->root.data, mntfh->size);
1868 		if (mntfh->size < sizeof(mntfh->data))
1869 			memset(mntfh->data + mntfh->size, 0,
1870 			       sizeof(mntfh->data) - mntfh->size);
1871 
1872 		/*
1873 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1874 		 * can deal with.
1875 		 */
1876 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1877 		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
1878 		args->rsize		= data->rsize;
1879 		args->wsize		= data->wsize;
1880 		args->timeo		= data->timeo;
1881 		args->retrans		= data->retrans;
1882 		args->acregmin		= data->acregmin;
1883 		args->acregmax		= data->acregmax;
1884 		args->acdirmin		= data->acdirmin;
1885 		args->acdirmax		= data->acdirmax;
1886 
1887 		memcpy(sap, &data->addr, sizeof(data->addr));
1888 		args->nfs_server.addrlen = sizeof(data->addr);
1889 		if (!nfs_verify_server_address(sap))
1890 			goto out_no_address;
1891 
1892 		if (!(data->flags & NFS_MOUNT_TCP))
1893 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1894 		/* N.B. caller will free nfs_server.hostname in all cases */
1895 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1896 		args->namlen		= data->namlen;
1897 		args->bsize		= data->bsize;
1898 
1899 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1900 			args->auth_flavors[0] = data->pseudoflavor;
1901 		if (!args->nfs_server.hostname)
1902 			goto out_nomem;
1903 
1904 		if (!(data->flags & NFS_MOUNT_NONLM))
1905 			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1906 					 NFS_MOUNT_LOCAL_FCNTL);
1907 		else
1908 			args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1909 					NFS_MOUNT_LOCAL_FCNTL);
1910 		/*
1911 		 * The legacy version 6 binary mount data from userspace has a
1912 		 * field used only to transport selinux information into the
1913 		 * the kernel.  To continue to support that functionality we
1914 		 * have a touch of selinux knowledge here in the NFS code. The
1915 		 * userspace code converted context=blah to just blah so we are
1916 		 * converting back to the full string selinux understands.
1917 		 */
1918 		if (data->context[0]){
1919 #ifdef CONFIG_SECURITY_SELINUX
1920 			int rc;
1921 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1922 			if (!opts_str)
1923 				return -ENOMEM;
1924 			strcpy(opts_str, "context=");
1925 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1926 			strcat(opts_str, &data->context[0]);
1927 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1928 			kfree(opts_str);
1929 			if (rc)
1930 				return rc;
1931 #else
1932 			return -EINVAL;
1933 #endif
1934 		}
1935 
1936 		break;
1937 	default: {
1938 		int status;
1939 
1940 		if (nfs_parse_mount_options((char *)options, args) == 0)
1941 			return -EINVAL;
1942 
1943 		if (!nfs_verify_server_address(sap))
1944 			goto out_no_address;
1945 
1946 		if (args->version == 4)
1947 #ifdef CONFIG_NFS_V4
1948 			return nfs4_validate_text_mount_data(options,
1949 							     args, dev_name);
1950 #else
1951 			goto out_v4_not_compiled;
1952 #endif
1953 
1954 		nfs_set_port(sap, &args->nfs_server.port, 0);
1955 
1956 		nfs_set_mount_transport_protocol(args);
1957 
1958 		status = nfs_parse_devname(dev_name,
1959 					   &args->nfs_server.hostname,
1960 					   PAGE_SIZE,
1961 					   &args->nfs_server.export_path,
1962 					   NFS_MAXPATHLEN);
1963 		if (!status)
1964 			status = nfs_try_mount(args, mntfh);
1965 
1966 		kfree(args->nfs_server.export_path);
1967 		args->nfs_server.export_path = NULL;
1968 
1969 		if (status)
1970 			return status;
1971 
1972 		break;
1973 		}
1974 	}
1975 
1976 #ifndef CONFIG_NFS_V3
1977 	if (args->version == 3)
1978 		goto out_v3_not_compiled;
1979 #endif /* !CONFIG_NFS_V3 */
1980 
1981 	return 0;
1982 
1983 out_no_data:
1984 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1985 	return -EINVAL;
1986 
1987 out_no_v3:
1988 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1989 		 data->version);
1990 	return -EINVAL;
1991 
1992 out_no_sec:
1993 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1994 	return -EINVAL;
1995 
1996 #ifndef CONFIG_NFS_V3
1997 out_v3_not_compiled:
1998 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1999 	return -EPROTONOSUPPORT;
2000 #endif /* !CONFIG_NFS_V3 */
2001 
2002 #ifndef CONFIG_NFS_V4
2003 out_v4_not_compiled:
2004 	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
2005 	return -EPROTONOSUPPORT;
2006 #endif /* !CONFIG_NFS_V4 */
2007 
2008 out_nomem:
2009 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
2010 	return -ENOMEM;
2011 
2012 out_no_address:
2013 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2014 	return -EINVAL;
2015 
2016 out_invalid_fh:
2017 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2018 	return -EINVAL;
2019 }
2020 
2021 static int
2022 nfs_compare_remount_data(struct nfs_server *nfss,
2023 			 struct nfs_parsed_mount_data *data)
2024 {
2025 	if (data->flags != nfss->flags ||
2026 	    data->rsize != nfss->rsize ||
2027 	    data->wsize != nfss->wsize ||
2028 	    data->retrans != nfss->client->cl_timeout->to_retries ||
2029 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2030 	    data->acregmin != nfss->acregmin / HZ ||
2031 	    data->acregmax != nfss->acregmax / HZ ||
2032 	    data->acdirmin != nfss->acdirmin / HZ ||
2033 	    data->acdirmax != nfss->acdirmax / HZ ||
2034 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2035 	    data->nfs_server.port != nfss->port ||
2036 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2037 	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2038 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
2039 		return -EINVAL;
2040 
2041 	return 0;
2042 }
2043 
2044 static int
2045 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2046 {
2047 	int error;
2048 	struct nfs_server *nfss = sb->s_fs_info;
2049 	struct nfs_parsed_mount_data *data;
2050 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2051 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2052 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2053 
2054 	/*
2055 	 * Userspace mount programs that send binary options generally send
2056 	 * them populated with default values. We have no way to know which
2057 	 * ones were explicitly specified. Fall back to legacy behavior and
2058 	 * just return success.
2059 	 */
2060 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2061 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
2062 					   options->version <= 6))))
2063 		return 0;
2064 
2065 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2066 	if (data == NULL)
2067 		return -ENOMEM;
2068 
2069 	/* fill out struct with values from existing mount */
2070 	data->flags = nfss->flags;
2071 	data->rsize = nfss->rsize;
2072 	data->wsize = nfss->wsize;
2073 	data->retrans = nfss->client->cl_timeout->to_retries;
2074 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2075 	data->acregmin = nfss->acregmin / HZ;
2076 	data->acregmax = nfss->acregmax / HZ;
2077 	data->acdirmin = nfss->acdirmin / HZ;
2078 	data->acdirmax = nfss->acdirmax / HZ;
2079 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2080 	data->nfs_server.port = nfss->port;
2081 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2082 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2083 		data->nfs_server.addrlen);
2084 
2085 	/* overwrite those values with any that were specified */
2086 	error = nfs_parse_mount_options((char *)options, data);
2087 	if (error < 0)
2088 		goto out;
2089 
2090 	/*
2091 	 * noac is a special case. It implies -o sync, but that's not
2092 	 * necessarily reflected in the mtab options. do_remount_sb
2093 	 * will clear MS_SYNCHRONOUS if -o sync wasn't specified in the
2094 	 * remount options, so we have to explicitly reset it.
2095 	 */
2096 	if (data->flags & NFS_MOUNT_NOAC)
2097 		*flags |= MS_SYNCHRONOUS;
2098 
2099 	/* compare new mount options with old ones */
2100 	error = nfs_compare_remount_data(nfss, data);
2101 out:
2102 	kfree(data);
2103 	return error;
2104 }
2105 
2106 /*
2107  * Initialise the common bits of the superblock
2108  */
2109 static inline void nfs_initialise_sb(struct super_block *sb)
2110 {
2111 	struct nfs_server *server = NFS_SB(sb);
2112 
2113 	sb->s_magic = NFS_SUPER_MAGIC;
2114 
2115 	/* We probably want something more informative here */
2116 	snprintf(sb->s_id, sizeof(sb->s_id),
2117 		 "%u:%u", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2118 
2119 	if (sb->s_blocksize == 0)
2120 		sb->s_blocksize = nfs_block_bits(server->wsize,
2121 						 &sb->s_blocksize_bits);
2122 
2123 	sb->s_bdi = &server->backing_dev_info;
2124 
2125 	nfs_super_set_maxbytes(sb, server->maxfilesize);
2126 }
2127 
2128 /*
2129  * Finish setting up an NFS2/3 superblock
2130  */
2131 static void nfs_fill_super(struct super_block *sb,
2132 			   struct nfs_parsed_mount_data *data)
2133 {
2134 	struct nfs_server *server = NFS_SB(sb);
2135 
2136 	sb->s_blocksize_bits = 0;
2137 	sb->s_blocksize = 0;
2138 	if (data->bsize)
2139 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2140 
2141 	if (server->nfs_client->rpc_ops->version == 3) {
2142 		/* The VFS shouldn't apply the umask to mode bits. We will do
2143 		 * so ourselves when necessary.
2144 		 */
2145 		sb->s_flags |= MS_POSIXACL;
2146 		sb->s_time_gran = 1;
2147 	}
2148 
2149 	sb->s_op = &nfs_sops;
2150  	nfs_initialise_sb(sb);
2151 }
2152 
2153 /*
2154  * Finish setting up a cloned NFS2/3 superblock
2155  */
2156 static void nfs_clone_super(struct super_block *sb,
2157 			    const struct super_block *old_sb)
2158 {
2159 	struct nfs_server *server = NFS_SB(sb);
2160 
2161 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2162 	sb->s_blocksize = old_sb->s_blocksize;
2163 	sb->s_maxbytes = old_sb->s_maxbytes;
2164 
2165 	if (server->nfs_client->rpc_ops->version == 3) {
2166 		/* The VFS shouldn't apply the umask to mode bits. We will do
2167 		 * so ourselves when necessary.
2168 		 */
2169 		sb->s_flags |= MS_POSIXACL;
2170 		sb->s_time_gran = 1;
2171 	}
2172 
2173 	sb->s_op = old_sb->s_op;
2174  	nfs_initialise_sb(sb);
2175 }
2176 
2177 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2178 {
2179 	const struct nfs_server *a = s->s_fs_info;
2180 	const struct rpc_clnt *clnt_a = a->client;
2181 	const struct rpc_clnt *clnt_b = b->client;
2182 
2183 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2184 		goto Ebusy;
2185 	if (a->nfs_client != b->nfs_client)
2186 		goto Ebusy;
2187 	if (a->flags != b->flags)
2188 		goto Ebusy;
2189 	if (a->wsize != b->wsize)
2190 		goto Ebusy;
2191 	if (a->rsize != b->rsize)
2192 		goto Ebusy;
2193 	if (a->acregmin != b->acregmin)
2194 		goto Ebusy;
2195 	if (a->acregmax != b->acregmax)
2196 		goto Ebusy;
2197 	if (a->acdirmin != b->acdirmin)
2198 		goto Ebusy;
2199 	if (a->acdirmax != b->acdirmax)
2200 		goto Ebusy;
2201 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2202 		goto Ebusy;
2203 	return 1;
2204 Ebusy:
2205 	return 0;
2206 }
2207 
2208 struct nfs_sb_mountdata {
2209 	struct nfs_server *server;
2210 	int mntflags;
2211 };
2212 
2213 static int nfs_set_super(struct super_block *s, void *data)
2214 {
2215 	struct nfs_sb_mountdata *sb_mntdata = data;
2216 	struct nfs_server *server = sb_mntdata->server;
2217 	int ret;
2218 
2219 	s->s_flags = sb_mntdata->mntflags;
2220 	s->s_fs_info = server;
2221 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
2222 	ret = set_anon_super(s, server);
2223 	if (ret == 0)
2224 		server->s_dev = s->s_dev;
2225 	return ret;
2226 }
2227 
2228 static int nfs_compare_super_address(struct nfs_server *server1,
2229 				     struct nfs_server *server2)
2230 {
2231 	struct sockaddr *sap1, *sap2;
2232 
2233 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2234 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2235 
2236 	if (sap1->sa_family != sap2->sa_family)
2237 		return 0;
2238 
2239 	switch (sap1->sa_family) {
2240 	case AF_INET: {
2241 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2242 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2243 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2244 			return 0;
2245 		if (sin1->sin_port != sin2->sin_port)
2246 			return 0;
2247 		break;
2248 	}
2249 	case AF_INET6: {
2250 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2251 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2252 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2253 			return 0;
2254 		if (sin1->sin6_port != sin2->sin6_port)
2255 			return 0;
2256 		break;
2257 	}
2258 	default:
2259 		return 0;
2260 	}
2261 
2262 	return 1;
2263 }
2264 
2265 static int nfs_compare_super(struct super_block *sb, void *data)
2266 {
2267 	struct nfs_sb_mountdata *sb_mntdata = data;
2268 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2269 	int mntflags = sb_mntdata->mntflags;
2270 
2271 	if (!nfs_compare_super_address(old, server))
2272 		return 0;
2273 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2274 	if (old->flags & NFS_MOUNT_UNSHARED)
2275 		return 0;
2276 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2277 		return 0;
2278 	return nfs_compare_mount_options(sb, server, mntflags);
2279 }
2280 
2281 static int nfs_bdi_register(struct nfs_server *server)
2282 {
2283 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2284 }
2285 
2286 static struct dentry *nfs_fs_mount(struct file_system_type *fs_type,
2287 	int flags, const char *dev_name, void *raw_data)
2288 {
2289 	struct nfs_server *server = NULL;
2290 	struct super_block *s;
2291 	struct nfs_parsed_mount_data *data;
2292 	struct nfs_fh *mntfh;
2293 	struct dentry *mntroot = ERR_PTR(-ENOMEM);
2294 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2295 	struct nfs_sb_mountdata sb_mntdata = {
2296 		.mntflags = flags,
2297 	};
2298 	int error;
2299 
2300 	data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2301 	mntfh = nfs_alloc_fhandle();
2302 	if (data == NULL || mntfh == NULL)
2303 		goto out;
2304 
2305 	/* Validate the mount data */
2306 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2307 	if (error < 0) {
2308 		mntroot = ERR_PTR(error);
2309 		goto out;
2310 	}
2311 
2312 #ifdef CONFIG_NFS_V4
2313 	if (data->version == 4) {
2314 		mntroot = nfs4_try_mount(flags, dev_name, data);
2315 		goto out;
2316 	}
2317 #endif	/* CONFIG_NFS_V4 */
2318 
2319 	/* Get a volume representation */
2320 	server = nfs_create_server(data, mntfh);
2321 	if (IS_ERR(server)) {
2322 		mntroot = ERR_CAST(server);
2323 		goto out;
2324 	}
2325 	sb_mntdata.server = server;
2326 
2327 	if (server->flags & NFS_MOUNT_UNSHARED)
2328 		compare_super = NULL;
2329 
2330 	/* -o noac implies -o sync */
2331 	if (server->flags & NFS_MOUNT_NOAC)
2332 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
2333 
2334 	/* Get a superblock - note that we may end up sharing one that already exists */
2335 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2336 	if (IS_ERR(s)) {
2337 		mntroot = ERR_CAST(s);
2338 		goto out_err_nosb;
2339 	}
2340 
2341 	if (s->s_fs_info != server) {
2342 		nfs_free_server(server);
2343 		server = NULL;
2344 	} else {
2345 		error = nfs_bdi_register(server);
2346 		if (error) {
2347 			mntroot = ERR_PTR(error);
2348 			goto error_splat_bdi;
2349 		}
2350 	}
2351 
2352 	if (!s->s_root) {
2353 		/* initial superblock/root creation */
2354 		nfs_fill_super(s, data);
2355 		nfs_fscache_get_super_cookie(s, data->fscache_uniq, NULL);
2356 	}
2357 
2358 	mntroot = nfs_get_root(s, mntfh, dev_name);
2359 	if (IS_ERR(mntroot))
2360 		goto error_splat_super;
2361 
2362 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2363 	if (error)
2364 		goto error_splat_root;
2365 
2366 	s->s_flags |= MS_ACTIVE;
2367 
2368 out:
2369 	nfs_free_parsed_mount_data(data);
2370 	nfs_free_fhandle(mntfh);
2371 	return mntroot;
2372 
2373 out_err_nosb:
2374 	nfs_free_server(server);
2375 	goto out;
2376 
2377 error_splat_root:
2378 	dput(mntroot);
2379 	mntroot = ERR_PTR(error);
2380 error_splat_super:
2381 	if (server && !s->s_root)
2382 		bdi_unregister(&server->backing_dev_info);
2383 error_splat_bdi:
2384 	deactivate_locked_super(s);
2385 	goto out;
2386 }
2387 
2388 /*
2389  * Ensure that we unregister the bdi before kill_anon_super
2390  * releases the device name
2391  */
2392 static void nfs_put_super(struct super_block *s)
2393 {
2394 	struct nfs_server *server = NFS_SB(s);
2395 
2396 	bdi_unregister(&server->backing_dev_info);
2397 }
2398 
2399 /*
2400  * Destroy an NFS2/3 superblock
2401  */
2402 static void nfs_kill_super(struct super_block *s)
2403 {
2404 	struct nfs_server *server = NFS_SB(s);
2405 
2406 	kill_anon_super(s);
2407 	nfs_fscache_release_super_cookie(s);
2408 	nfs_free_server(server);
2409 }
2410 
2411 /*
2412  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2413  */
2414 static struct dentry *
2415 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2416 		const char *dev_name, void *raw_data)
2417 {
2418 	struct nfs_clone_mount *data = raw_data;
2419 	struct super_block *s;
2420 	struct nfs_server *server;
2421 	struct dentry *mntroot;
2422 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2423 	struct nfs_sb_mountdata sb_mntdata = {
2424 		.mntflags = flags,
2425 	};
2426 	int error;
2427 
2428 	dprintk("--> nfs_xdev_mount()\n");
2429 
2430 	/* create a new volume representation */
2431 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
2432 	if (IS_ERR(server)) {
2433 		error = PTR_ERR(server);
2434 		goto out_err_noserver;
2435 	}
2436 	sb_mntdata.server = server;
2437 
2438 	if (server->flags & NFS_MOUNT_UNSHARED)
2439 		compare_super = NULL;
2440 
2441 	/* -o noac implies -o sync */
2442 	if (server->flags & NFS_MOUNT_NOAC)
2443 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
2444 
2445 	/* Get a superblock - note that we may end up sharing one that already exists */
2446 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2447 	if (IS_ERR(s)) {
2448 		error = PTR_ERR(s);
2449 		goto out_err_nosb;
2450 	}
2451 
2452 	if (s->s_fs_info != server) {
2453 		nfs_free_server(server);
2454 		server = NULL;
2455 	} else {
2456 		error = nfs_bdi_register(server);
2457 		if (error)
2458 			goto error_splat_bdi;
2459 	}
2460 
2461 	if (!s->s_root) {
2462 		/* initial superblock/root creation */
2463 		nfs_clone_super(s, data->sb);
2464 		nfs_fscache_get_super_cookie(s, NULL, data);
2465 	}
2466 
2467 	mntroot = nfs_get_root(s, data->fh, dev_name);
2468 	if (IS_ERR(mntroot)) {
2469 		error = PTR_ERR(mntroot);
2470 		goto error_splat_super;
2471 	}
2472 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2473 		dput(mntroot);
2474 		error = -ESTALE;
2475 		goto error_splat_super;
2476 	}
2477 
2478 	s->s_flags |= MS_ACTIVE;
2479 
2480 	/* clone any lsm security options from the parent to the new sb */
2481 	security_sb_clone_mnt_opts(data->sb, s);
2482 
2483 	dprintk("<-- nfs_xdev_mount() = 0\n");
2484 	return mntroot;
2485 
2486 out_err_nosb:
2487 	nfs_free_server(server);
2488 out_err_noserver:
2489 	dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2490 	return ERR_PTR(error);
2491 
2492 error_splat_super:
2493 	if (server && !s->s_root)
2494 		bdi_unregister(&server->backing_dev_info);
2495 error_splat_bdi:
2496 	deactivate_locked_super(s);
2497 	dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2498 	return ERR_PTR(error);
2499 }
2500 
2501 #ifdef CONFIG_NFS_V4
2502 
2503 /*
2504  * Finish setting up a cloned NFS4 superblock
2505  */
2506 static void nfs4_clone_super(struct super_block *sb,
2507 			    const struct super_block *old_sb)
2508 {
2509 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2510 	sb->s_blocksize = old_sb->s_blocksize;
2511 	sb->s_maxbytes = old_sb->s_maxbytes;
2512 	sb->s_time_gran = 1;
2513 	sb->s_op = old_sb->s_op;
2514 	/*
2515 	 * The VFS shouldn't apply the umask to mode bits. We will do
2516 	 * so ourselves when necessary.
2517 	 */
2518 	sb->s_flags  |= MS_POSIXACL;
2519 	sb->s_xattr  = old_sb->s_xattr;
2520 	nfs_initialise_sb(sb);
2521 }
2522 
2523 /*
2524  * Set up an NFS4 superblock
2525  */
2526 static void nfs4_fill_super(struct super_block *sb)
2527 {
2528 	sb->s_time_gran = 1;
2529 	sb->s_op = &nfs4_sops;
2530 	/*
2531 	 * The VFS shouldn't apply the umask to mode bits. We will do
2532 	 * so ourselves when necessary.
2533 	 */
2534 	sb->s_flags  |= MS_POSIXACL;
2535 	sb->s_xattr = nfs4_xattr_handlers;
2536 	nfs_initialise_sb(sb);
2537 }
2538 
2539 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2540 {
2541 	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2542 			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2543 }
2544 
2545 static int nfs4_validate_text_mount_data(void *options,
2546 					 struct nfs_parsed_mount_data *args,
2547 					 const char *dev_name)
2548 {
2549 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2550 
2551 	nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2552 
2553 	nfs_validate_transport_protocol(args);
2554 
2555 	nfs4_validate_mount_flags(args);
2556 
2557 	if (args->version != 4) {
2558 		dfprintk(MOUNT,
2559 			 "NFS4: Illegal mount version\n");
2560 		return -EINVAL;
2561 	}
2562 
2563 	if (args->auth_flavor_len > 1) {
2564 		dfprintk(MOUNT,
2565 			 "NFS4: Too many RPC auth flavours specified\n");
2566 		return -EINVAL;
2567 	}
2568 
2569 	return nfs_parse_devname(dev_name,
2570 				   &args->nfs_server.hostname,
2571 				   NFS4_MAXNAMLEN,
2572 				   &args->nfs_server.export_path,
2573 				   NFS4_MAXPATHLEN);
2574 }
2575 
2576 /*
2577  * Validate NFSv4 mount options
2578  */
2579 static int nfs4_validate_mount_data(void *options,
2580 				    struct nfs_parsed_mount_data *args,
2581 				    const char *dev_name)
2582 {
2583 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2584 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2585 	char *c;
2586 
2587 	if (data == NULL)
2588 		goto out_no_data;
2589 
2590 	switch (data->version) {
2591 	case 1:
2592 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2593 			goto out_no_address;
2594 		if (data->host_addrlen == 0)
2595 			goto out_no_address;
2596 		args->nfs_server.addrlen = data->host_addrlen;
2597 		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2598 			return -EFAULT;
2599 		if (!nfs_verify_server_address(sap))
2600 			goto out_no_address;
2601 
2602 		if (data->auth_flavourlen) {
2603 			if (data->auth_flavourlen > 1)
2604 				goto out_inval_auth;
2605 			if (copy_from_user(&args->auth_flavors[0],
2606 					   data->auth_flavours,
2607 					   sizeof(args->auth_flavors[0])))
2608 				return -EFAULT;
2609 		}
2610 
2611 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2612 		if (IS_ERR(c))
2613 			return PTR_ERR(c);
2614 		args->nfs_server.hostname = c;
2615 
2616 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2617 		if (IS_ERR(c))
2618 			return PTR_ERR(c);
2619 		args->nfs_server.export_path = c;
2620 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2621 
2622 		c = strndup_user(data->client_addr.data, 16);
2623 		if (IS_ERR(c))
2624 			return PTR_ERR(c);
2625 		args->client_address = c;
2626 
2627 		/*
2628 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2629 		 * can deal with.
2630 		 */
2631 
2632 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2633 		args->rsize	= data->rsize;
2634 		args->wsize	= data->wsize;
2635 		args->timeo	= data->timeo;
2636 		args->retrans	= data->retrans;
2637 		args->acregmin	= data->acregmin;
2638 		args->acregmax	= data->acregmax;
2639 		args->acdirmin	= data->acdirmin;
2640 		args->acdirmax	= data->acdirmax;
2641 		args->nfs_server.protocol = data->proto;
2642 		nfs_validate_transport_protocol(args);
2643 
2644 		break;
2645 	default:
2646 		if (nfs_parse_mount_options((char *)options, args) == 0)
2647 			return -EINVAL;
2648 
2649 		if (!nfs_verify_server_address(sap))
2650 			return -EINVAL;
2651 
2652 		return nfs4_validate_text_mount_data(options, args, dev_name);
2653 	}
2654 
2655 	return 0;
2656 
2657 out_no_data:
2658 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2659 	return -EINVAL;
2660 
2661 out_inval_auth:
2662 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2663 		 data->auth_flavourlen);
2664 	return -EINVAL;
2665 
2666 out_no_address:
2667 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2668 	return -EINVAL;
2669 }
2670 
2671 /*
2672  * Get the superblock for the NFS4 root partition
2673  */
2674 static struct dentry *
2675 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2676 		  const char *dev_name, void *raw_data)
2677 {
2678 	struct nfs_parsed_mount_data *data = raw_data;
2679 	struct super_block *s;
2680 	struct nfs_server *server;
2681 	struct nfs_fh *mntfh;
2682 	struct dentry *mntroot;
2683 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2684 	struct nfs_sb_mountdata sb_mntdata = {
2685 		.mntflags = flags,
2686 	};
2687 	int error = -ENOMEM;
2688 
2689 	mntfh = nfs_alloc_fhandle();
2690 	if (data == NULL || mntfh == NULL)
2691 		goto out;
2692 
2693 	/* Get a volume representation */
2694 	server = nfs4_create_server(data, mntfh);
2695 	if (IS_ERR(server)) {
2696 		error = PTR_ERR(server);
2697 		goto out;
2698 	}
2699 	sb_mntdata.server = server;
2700 
2701 	if (server->flags & NFS4_MOUNT_UNSHARED)
2702 		compare_super = NULL;
2703 
2704 	/* -o noac implies -o sync */
2705 	if (server->flags & NFS_MOUNT_NOAC)
2706 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
2707 
2708 	/* Get a superblock - note that we may end up sharing one that already exists */
2709 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2710 	if (IS_ERR(s)) {
2711 		error = PTR_ERR(s);
2712 		goto out_free;
2713 	}
2714 
2715 	if (s->s_fs_info != server) {
2716 		nfs_free_server(server);
2717 		server = NULL;
2718 	} else {
2719 		error = nfs_bdi_register(server);
2720 		if (error)
2721 			goto error_splat_bdi;
2722 	}
2723 
2724 	if (!s->s_root) {
2725 		/* initial superblock/root creation */
2726 		nfs4_fill_super(s);
2727 		nfs_fscache_get_super_cookie(s, data->fscache_uniq, NULL);
2728 	}
2729 
2730 	mntroot = nfs4_get_root(s, mntfh, dev_name);
2731 	if (IS_ERR(mntroot)) {
2732 		error = PTR_ERR(mntroot);
2733 		goto error_splat_super;
2734 	}
2735 
2736 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2737 	if (error)
2738 		goto error_splat_root;
2739 
2740 	s->s_flags |= MS_ACTIVE;
2741 
2742 	nfs_free_fhandle(mntfh);
2743 	return mntroot;
2744 
2745 out:
2746 	nfs_free_fhandle(mntfh);
2747 	return ERR_PTR(error);
2748 
2749 out_free:
2750 	nfs_free_server(server);
2751 	goto out;
2752 
2753 error_splat_root:
2754 	dput(mntroot);
2755 error_splat_super:
2756 	if (server && !s->s_root)
2757 		bdi_unregister(&server->backing_dev_info);
2758 error_splat_bdi:
2759 	deactivate_locked_super(s);
2760 	goto out;
2761 }
2762 
2763 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2764 		int flags, void *data, const char *hostname)
2765 {
2766 	struct vfsmount *root_mnt;
2767 	char *root_devname;
2768 	size_t len;
2769 
2770 	len = strlen(hostname) + 5;
2771 	root_devname = kmalloc(len, GFP_KERNEL);
2772 	if (root_devname == NULL)
2773 		return ERR_PTR(-ENOMEM);
2774 	/* Does hostname needs to be enclosed in brackets? */
2775 	if (strchr(hostname, ':'))
2776 		snprintf(root_devname, len, "[%s]:/", hostname);
2777 	else
2778 		snprintf(root_devname, len, "%s:/", hostname);
2779 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2780 	kfree(root_devname);
2781 	return root_mnt;
2782 }
2783 
2784 struct nfs_referral_count {
2785 	struct list_head list;
2786 	const struct task_struct *task;
2787 	unsigned int referral_count;
2788 };
2789 
2790 static LIST_HEAD(nfs_referral_count_list);
2791 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2792 
2793 static struct nfs_referral_count *nfs_find_referral_count(void)
2794 {
2795 	struct nfs_referral_count *p;
2796 
2797 	list_for_each_entry(p, &nfs_referral_count_list, list) {
2798 		if (p->task == current)
2799 			return p;
2800 	}
2801 	return NULL;
2802 }
2803 
2804 #define NFS_MAX_NESTED_REFERRALS 2
2805 
2806 static int nfs_referral_loop_protect(void)
2807 {
2808 	struct nfs_referral_count *p, *new;
2809 	int ret = -ENOMEM;
2810 
2811 	new = kmalloc(sizeof(*new), GFP_KERNEL);
2812 	if (!new)
2813 		goto out;
2814 	new->task = current;
2815 	new->referral_count = 1;
2816 
2817 	ret = 0;
2818 	spin_lock(&nfs_referral_count_list_lock);
2819 	p = nfs_find_referral_count();
2820 	if (p != NULL) {
2821 		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2822 			ret = -ELOOP;
2823 		else
2824 			p->referral_count++;
2825 	} else {
2826 		list_add(&new->list, &nfs_referral_count_list);
2827 		new = NULL;
2828 	}
2829 	spin_unlock(&nfs_referral_count_list_lock);
2830 	kfree(new);
2831 out:
2832 	return ret;
2833 }
2834 
2835 static void nfs_referral_loop_unprotect(void)
2836 {
2837 	struct nfs_referral_count *p;
2838 
2839 	spin_lock(&nfs_referral_count_list_lock);
2840 	p = nfs_find_referral_count();
2841 	p->referral_count--;
2842 	if (p->referral_count == 0)
2843 		list_del(&p->list);
2844 	else
2845 		p = NULL;
2846 	spin_unlock(&nfs_referral_count_list_lock);
2847 	kfree(p);
2848 }
2849 
2850 static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
2851 		const char *export_path)
2852 {
2853 	struct dentry *dentry;
2854 	int err;
2855 
2856 	if (IS_ERR(root_mnt))
2857 		return ERR_CAST(root_mnt);
2858 
2859 	err = nfs_referral_loop_protect();
2860 	if (err) {
2861 		mntput(root_mnt);
2862 		return ERR_PTR(err);
2863 	}
2864 
2865 	dentry = mount_subtree(root_mnt, export_path);
2866 	nfs_referral_loop_unprotect();
2867 
2868 	return dentry;
2869 }
2870 
2871 static struct dentry *nfs4_try_mount(int flags, const char *dev_name,
2872 			 struct nfs_parsed_mount_data *data)
2873 {
2874 	char *export_path;
2875 	struct vfsmount *root_mnt;
2876 	struct dentry *res;
2877 
2878 	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2879 
2880 	export_path = data->nfs_server.export_path;
2881 	data->nfs_server.export_path = "/";
2882 	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2883 			data->nfs_server.hostname);
2884 	data->nfs_server.export_path = export_path;
2885 
2886 	res = nfs_follow_remote_path(root_mnt, export_path);
2887 
2888 	dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
2889 			IS_ERR(res) ? PTR_ERR(res) : 0,
2890 			IS_ERR(res) ? " [error]" : "");
2891 	return res;
2892 }
2893 
2894 /*
2895  * Get the superblock for an NFS4 mountpoint
2896  */
2897 static struct dentry *nfs4_mount(struct file_system_type *fs_type,
2898 	int flags, const char *dev_name, void *raw_data)
2899 {
2900 	struct nfs_parsed_mount_data *data;
2901 	int error = -ENOMEM;
2902 	struct dentry *res = ERR_PTR(-ENOMEM);
2903 
2904 	data = nfs_alloc_parsed_mount_data(4);
2905 	if (data == NULL)
2906 		goto out;
2907 
2908 	/* Validate the mount data */
2909 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2910 	if (error < 0) {
2911 		res = ERR_PTR(error);
2912 		goto out;
2913 	}
2914 
2915 	res = nfs4_try_mount(flags, dev_name, data);
2916 	if (IS_ERR(res))
2917 		error = PTR_ERR(res);
2918 
2919 out:
2920 	nfs_free_parsed_mount_data(data);
2921 	dprintk("<-- nfs4_mount() = %d%s\n", error,
2922 			error != 0 ? " [error]" : "");
2923 	return res;
2924 }
2925 
2926 static void nfs4_kill_super(struct super_block *sb)
2927 {
2928 	struct nfs_server *server = NFS_SB(sb);
2929 
2930 	dprintk("--> %s\n", __func__);
2931 	nfs_super_return_all_delegations(sb);
2932 	kill_anon_super(sb);
2933 	nfs_fscache_release_super_cookie(sb);
2934 	nfs_free_server(server);
2935 	dprintk("<-- %s\n", __func__);
2936 }
2937 
2938 /*
2939  * Clone an NFS4 server record on xdev traversal (FSID-change)
2940  */
2941 static struct dentry *
2942 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2943 		 const char *dev_name, void *raw_data)
2944 {
2945 	struct nfs_clone_mount *data = raw_data;
2946 	struct super_block *s;
2947 	struct nfs_server *server;
2948 	struct dentry *mntroot;
2949 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2950 	struct nfs_sb_mountdata sb_mntdata = {
2951 		.mntflags = flags,
2952 	};
2953 	int error;
2954 
2955 	dprintk("--> nfs4_xdev_mount()\n");
2956 
2957 	/* create a new volume representation */
2958 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr, data->authflavor);
2959 	if (IS_ERR(server)) {
2960 		error = PTR_ERR(server);
2961 		goto out_err_noserver;
2962 	}
2963 	sb_mntdata.server = server;
2964 
2965 	if (server->flags & NFS4_MOUNT_UNSHARED)
2966 		compare_super = NULL;
2967 
2968 	/* -o noac implies -o sync */
2969 	if (server->flags & NFS_MOUNT_NOAC)
2970 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
2971 
2972 	/* Get a superblock - note that we may end up sharing one that already exists */
2973 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2974 	if (IS_ERR(s)) {
2975 		error = PTR_ERR(s);
2976 		goto out_err_nosb;
2977 	}
2978 
2979 	if (s->s_fs_info != server) {
2980 		nfs_free_server(server);
2981 		server = NULL;
2982 	} else {
2983 		error = nfs_bdi_register(server);
2984 		if (error)
2985 			goto error_splat_bdi;
2986 	}
2987 
2988 	if (!s->s_root) {
2989 		/* initial superblock/root creation */
2990 		nfs4_clone_super(s, data->sb);
2991 		nfs_fscache_get_super_cookie(s, NULL, data);
2992 	}
2993 
2994 	mntroot = nfs4_get_root(s, data->fh, dev_name);
2995 	if (IS_ERR(mntroot)) {
2996 		error = PTR_ERR(mntroot);
2997 		goto error_splat_super;
2998 	}
2999 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3000 		dput(mntroot);
3001 		error = -ESTALE;
3002 		goto error_splat_super;
3003 	}
3004 
3005 	s->s_flags |= MS_ACTIVE;
3006 
3007 	security_sb_clone_mnt_opts(data->sb, s);
3008 
3009 	dprintk("<-- nfs4_xdev_mount() = 0\n");
3010 	return mntroot;
3011 
3012 out_err_nosb:
3013 	nfs_free_server(server);
3014 out_err_noserver:
3015 	dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3016 	return ERR_PTR(error);
3017 
3018 error_splat_super:
3019 	if (server && !s->s_root)
3020 		bdi_unregister(&server->backing_dev_info);
3021 error_splat_bdi:
3022 	deactivate_locked_super(s);
3023 	dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3024 	return ERR_PTR(error);
3025 }
3026 
3027 static struct dentry *
3028 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3029 			   const char *dev_name, void *raw_data)
3030 {
3031 	struct nfs_clone_mount *data = raw_data;
3032 	struct super_block *s;
3033 	struct nfs_server *server;
3034 	struct dentry *mntroot;
3035 	struct nfs_fh *mntfh;
3036 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3037 	struct nfs_sb_mountdata sb_mntdata = {
3038 		.mntflags = flags,
3039 	};
3040 	int error = -ENOMEM;
3041 
3042 	dprintk("--> nfs4_referral_get_sb()\n");
3043 
3044 	mntfh = nfs_alloc_fhandle();
3045 	if (mntfh == NULL)
3046 		goto out_err_nofh;
3047 
3048 	/* create a new volume representation */
3049 	server = nfs4_create_referral_server(data, mntfh);
3050 	if (IS_ERR(server)) {
3051 		error = PTR_ERR(server);
3052 		goto out_err_noserver;
3053 	}
3054 	sb_mntdata.server = server;
3055 
3056 	if (server->flags & NFS4_MOUNT_UNSHARED)
3057 		compare_super = NULL;
3058 
3059 	/* -o noac implies -o sync */
3060 	if (server->flags & NFS_MOUNT_NOAC)
3061 		sb_mntdata.mntflags |= MS_SYNCHRONOUS;
3062 
3063 	/* Get a superblock - note that we may end up sharing one that already exists */
3064 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3065 	if (IS_ERR(s)) {
3066 		error = PTR_ERR(s);
3067 		goto out_err_nosb;
3068 	}
3069 
3070 	if (s->s_fs_info != server) {
3071 		nfs_free_server(server);
3072 		server = NULL;
3073 	} else {
3074 		error = nfs_bdi_register(server);
3075 		if (error)
3076 			goto error_splat_bdi;
3077 	}
3078 
3079 	if (!s->s_root) {
3080 		/* initial superblock/root creation */
3081 		nfs4_fill_super(s);
3082 		nfs_fscache_get_super_cookie(s, NULL, data);
3083 	}
3084 
3085 	mntroot = nfs4_get_root(s, mntfh, dev_name);
3086 	if (IS_ERR(mntroot)) {
3087 		error = PTR_ERR(mntroot);
3088 		goto error_splat_super;
3089 	}
3090 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3091 		dput(mntroot);
3092 		error = -ESTALE;
3093 		goto error_splat_super;
3094 	}
3095 
3096 	s->s_flags |= MS_ACTIVE;
3097 
3098 	security_sb_clone_mnt_opts(data->sb, s);
3099 
3100 	nfs_free_fhandle(mntfh);
3101 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
3102 	return mntroot;
3103 
3104 out_err_nosb:
3105 	nfs_free_server(server);
3106 out_err_noserver:
3107 	nfs_free_fhandle(mntfh);
3108 out_err_nofh:
3109 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3110 	return ERR_PTR(error);
3111 
3112 error_splat_super:
3113 	if (server && !s->s_root)
3114 		bdi_unregister(&server->backing_dev_info);
3115 error_splat_bdi:
3116 	deactivate_locked_super(s);
3117 	nfs_free_fhandle(mntfh);
3118 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3119 	return ERR_PTR(error);
3120 }
3121 
3122 /*
3123  * Create an NFS4 server record on referral traversal
3124  */
3125 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
3126 		int flags, const char *dev_name, void *raw_data)
3127 {
3128 	struct nfs_clone_mount *data = raw_data;
3129 	char *export_path;
3130 	struct vfsmount *root_mnt;
3131 	struct dentry *res;
3132 
3133 	dprintk("--> nfs4_referral_mount()\n");
3134 
3135 	export_path = data->mnt_path;
3136 	data->mnt_path = "/";
3137 
3138 	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3139 			flags, data, data->hostname);
3140 	data->mnt_path = export_path;
3141 
3142 	res = nfs_follow_remote_path(root_mnt, export_path);
3143 	dprintk("<-- nfs4_referral_mount() = %ld%s\n",
3144 			IS_ERR(res) ? PTR_ERR(res) : 0,
3145 			IS_ERR(res) ? " [error]" : "");
3146 	return res;
3147 }
3148 
3149 #endif /* CONFIG_NFS_V4 */
3150