xref: /openbmc/linux/fs/nfs/super.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
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/mnt_namespace.h>
45 #include <linux/namei.h>
46 #include <linux/nfs_idmap.h>
47 #include <linux/vfs.h>
48 #include <linux/inet.h>
49 #include <linux/in6.h>
50 #include <linux/slab.h>
51 #include <net/ipv6.h>
52 #include <linux/netdevice.h>
53 #include <linux/nfs_xdr.h>
54 #include <linux/magic.h>
55 #include <linux/parser.h>
56 
57 #include <asm/system.h>
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 
67 #define NFSDBG_FACILITY		NFSDBG_VFS
68 
69 #ifdef CONFIG_NFS_V3
70 #define NFS_DEFAULT_VERSION 3
71 #else
72 #define NFS_DEFAULT_VERSION 2
73 #endif
74 
75 enum {
76 	/* Mount options that take no arguments */
77 	Opt_soft, Opt_hard,
78 	Opt_posix, Opt_noposix,
79 	Opt_cto, Opt_nocto,
80 	Opt_ac, Opt_noac,
81 	Opt_lock, Opt_nolock,
82 	Opt_v2, Opt_v3, Opt_v4,
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_nfsvers,
101 	Opt_minorversion,
102 
103 	/* Mount options that take string arguments */
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_v2, "v2" },
136 	{ Opt_v3, "v3" },
137 	{ Opt_v4, "v4" },
138 	{ Opt_udp, "udp" },
139 	{ Opt_tcp, "tcp" },
140 	{ Opt_rdma, "rdma" },
141 	{ Opt_acl, "acl" },
142 	{ Opt_noacl, "noacl" },
143 	{ Opt_rdirplus, "rdirplus" },
144 	{ Opt_nordirplus, "nordirplus" },
145 	{ Opt_sharecache, "sharecache" },
146 	{ Opt_nosharecache, "nosharecache" },
147 	{ Opt_resvport, "resvport" },
148 	{ Opt_noresvport, "noresvport" },
149 	{ Opt_fscache, "fsc" },
150 	{ Opt_nofscache, "nofsc" },
151 
152 	{ Opt_port, "port=%s" },
153 	{ Opt_rsize, "rsize=%s" },
154 	{ Opt_wsize, "wsize=%s" },
155 	{ Opt_bsize, "bsize=%s" },
156 	{ Opt_timeo, "timeo=%s" },
157 	{ Opt_retrans, "retrans=%s" },
158 	{ Opt_acregmin, "acregmin=%s" },
159 	{ Opt_acregmax, "acregmax=%s" },
160 	{ Opt_acdirmin, "acdirmin=%s" },
161 	{ Opt_acdirmax, "acdirmax=%s" },
162 	{ Opt_actimeo, "actimeo=%s" },
163 	{ Opt_namelen, "namlen=%s" },
164 	{ Opt_mountport, "mountport=%s" },
165 	{ Opt_mountvers, "mountvers=%s" },
166 	{ Opt_nfsvers, "nfsvers=%s" },
167 	{ Opt_nfsvers, "vers=%s" },
168 	{ Opt_minorversion, "minorversion=%s" },
169 
170 	{ Opt_sec, "sec=%s" },
171 	{ Opt_proto, "proto=%s" },
172 	{ Opt_mountproto, "mountproto=%s" },
173 	{ Opt_addr, "addr=%s" },
174 	{ Opt_clientaddr, "clientaddr=%s" },
175 	{ Opt_mounthost, "mounthost=%s" },
176 	{ Opt_mountaddr, "mountaddr=%s" },
177 
178 	{ Opt_lookupcache, "lookupcache=%s" },
179 	{ Opt_fscache_uniq, "fsc=%s" },
180 	{ Opt_local_lock, "local_lock=%s" },
181 
182 	{ Opt_err, NULL }
183 };
184 
185 enum {
186 	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
187 
188 	Opt_xprt_err
189 };
190 
191 static const match_table_t nfs_xprt_protocol_tokens = {
192 	{ Opt_xprt_udp, "udp" },
193 	{ Opt_xprt_udp6, "udp6" },
194 	{ Opt_xprt_tcp, "tcp" },
195 	{ Opt_xprt_tcp6, "tcp6" },
196 	{ Opt_xprt_rdma, "rdma" },
197 
198 	{ Opt_xprt_err, NULL }
199 };
200 
201 enum {
202 	Opt_sec_none, Opt_sec_sys,
203 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
204 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
205 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
206 
207 	Opt_sec_err
208 };
209 
210 static const match_table_t nfs_secflavor_tokens = {
211 	{ Opt_sec_none, "none" },
212 	{ Opt_sec_none, "null" },
213 	{ Opt_sec_sys, "sys" },
214 
215 	{ Opt_sec_krb5, "krb5" },
216 	{ Opt_sec_krb5i, "krb5i" },
217 	{ Opt_sec_krb5p, "krb5p" },
218 
219 	{ Opt_sec_lkey, "lkey" },
220 	{ Opt_sec_lkeyi, "lkeyi" },
221 	{ Opt_sec_lkeyp, "lkeyp" },
222 
223 	{ Opt_sec_spkm, "spkm3" },
224 	{ Opt_sec_spkmi, "spkm3i" },
225 	{ Opt_sec_spkmp, "spkm3p" },
226 
227 	{ Opt_sec_err, NULL }
228 };
229 
230 enum {
231 	Opt_lookupcache_all, Opt_lookupcache_positive,
232 	Opt_lookupcache_none,
233 
234 	Opt_lookupcache_err
235 };
236 
237 static match_table_t nfs_lookupcache_tokens = {
238 	{ Opt_lookupcache_all, "all" },
239 	{ Opt_lookupcache_positive, "pos" },
240 	{ Opt_lookupcache_positive, "positive" },
241 	{ Opt_lookupcache_none, "none" },
242 
243 	{ Opt_lookupcache_err, NULL }
244 };
245 
246 enum {
247 	Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
248 	Opt_local_lock_none,
249 
250 	Opt_local_lock_err
251 };
252 
253 static match_table_t nfs_local_lock_tokens = {
254 	{ Opt_local_lock_all, "all" },
255 	{ Opt_local_lock_flock, "flock" },
256 	{ Opt_local_lock_posix, "posix" },
257 	{ Opt_local_lock_none, "none" },
258 
259 	{ Opt_local_lock_err, NULL }
260 };
261 
262 
263 static void nfs_umount_begin(struct super_block *);
264 static int  nfs_statfs(struct dentry *, struct kstatfs *);
265 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
266 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
267 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
268 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
269 		int flags, const char *dev_name, void *raw_data);
270 static void nfs_put_super(struct super_block *);
271 static void nfs_kill_super(struct super_block *);
272 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
273 
274 static struct file_system_type nfs_fs_type = {
275 	.owner		= THIS_MODULE,
276 	.name		= "nfs",
277 	.get_sb		= nfs_get_sb,
278 	.kill_sb	= nfs_kill_super,
279 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
280 };
281 
282 struct file_system_type nfs_xdev_fs_type = {
283 	.owner		= THIS_MODULE,
284 	.name		= "nfs",
285 	.mount		= nfs_xdev_mount,
286 	.kill_sb	= nfs_kill_super,
287 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
288 };
289 
290 static const struct super_operations nfs_sops = {
291 	.alloc_inode	= nfs_alloc_inode,
292 	.destroy_inode	= nfs_destroy_inode,
293 	.write_inode	= nfs_write_inode,
294 	.put_super	= nfs_put_super,
295 	.statfs		= nfs_statfs,
296 	.evict_inode	= nfs_evict_inode,
297 	.umount_begin	= nfs_umount_begin,
298 	.show_options	= nfs_show_options,
299 	.show_stats	= nfs_show_stats,
300 	.remount_fs	= nfs_remount,
301 };
302 
303 #ifdef CONFIG_NFS_V4
304 static int nfs4_validate_text_mount_data(void *options,
305 	struct nfs_parsed_mount_data *args, const char *dev_name);
306 static int nfs4_try_mount(int flags, const char *dev_name,
307 	struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
308 static int nfs4_get_sb(struct file_system_type *fs_type,
309 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
310 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
311 	int flags, const char *dev_name, void *raw_data);
312 static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
313 	int flags, const char *dev_name, void *raw_data);
314 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
315 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
316 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
317 	int flags, const char *dev_name, void *raw_data);
318 static void nfs4_kill_super(struct super_block *sb);
319 
320 static struct file_system_type nfs4_fs_type = {
321 	.owner		= THIS_MODULE,
322 	.name		= "nfs4",
323 	.get_sb		= nfs4_get_sb,
324 	.kill_sb	= nfs4_kill_super,
325 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
326 };
327 
328 static struct file_system_type nfs4_remote_fs_type = {
329 	.owner		= THIS_MODULE,
330 	.name		= "nfs4",
331 	.mount		= nfs4_remote_mount,
332 	.kill_sb	= nfs4_kill_super,
333 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
334 };
335 
336 struct file_system_type nfs4_xdev_fs_type = {
337 	.owner		= THIS_MODULE,
338 	.name		= "nfs4",
339 	.mount		= nfs4_xdev_mount,
340 	.kill_sb	= nfs4_kill_super,
341 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
342 };
343 
344 static struct file_system_type nfs4_remote_referral_fs_type = {
345 	.owner		= THIS_MODULE,
346 	.name		= "nfs4",
347 	.mount		= nfs4_remote_referral_mount,
348 	.kill_sb	= nfs4_kill_super,
349 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
350 };
351 
352 struct file_system_type nfs4_referral_fs_type = {
353 	.owner		= THIS_MODULE,
354 	.name		= "nfs4",
355 	.get_sb		= nfs4_referral_get_sb,
356 	.kill_sb	= nfs4_kill_super,
357 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
358 };
359 
360 static const struct super_operations nfs4_sops = {
361 	.alloc_inode	= nfs_alloc_inode,
362 	.destroy_inode	= nfs_destroy_inode,
363 	.write_inode	= nfs_write_inode,
364 	.put_super	= nfs_put_super,
365 	.statfs		= nfs_statfs,
366 	.evict_inode	= nfs4_evict_inode,
367 	.umount_begin	= nfs_umount_begin,
368 	.show_options	= nfs_show_options,
369 	.show_stats	= nfs_show_stats,
370 	.remount_fs	= nfs_remount,
371 };
372 #endif
373 
374 static struct shrinker acl_shrinker = {
375 	.shrink		= nfs_access_cache_shrinker,
376 	.seeks		= DEFAULT_SEEKS,
377 };
378 
379 /*
380  * Register the NFS filesystems
381  */
382 int __init register_nfs_fs(void)
383 {
384 	int ret;
385 
386         ret = register_filesystem(&nfs_fs_type);
387 	if (ret < 0)
388 		goto error_0;
389 
390 	ret = nfs_register_sysctl();
391 	if (ret < 0)
392 		goto error_1;
393 #ifdef CONFIG_NFS_V4
394 	ret = register_filesystem(&nfs4_fs_type);
395 	if (ret < 0)
396 		goto error_2;
397 #endif
398 	register_shrinker(&acl_shrinker);
399 	return 0;
400 
401 #ifdef CONFIG_NFS_V4
402 error_2:
403 	nfs_unregister_sysctl();
404 #endif
405 error_1:
406 	unregister_filesystem(&nfs_fs_type);
407 error_0:
408 	return ret;
409 }
410 
411 /*
412  * Unregister the NFS filesystems
413  */
414 void __exit unregister_nfs_fs(void)
415 {
416 	unregister_shrinker(&acl_shrinker);
417 #ifdef CONFIG_NFS_V4
418 	unregister_filesystem(&nfs4_fs_type);
419 #endif
420 	nfs_unregister_sysctl();
421 	unregister_filesystem(&nfs_fs_type);
422 }
423 
424 void nfs_sb_active(struct super_block *sb)
425 {
426 	struct nfs_server *server = NFS_SB(sb);
427 
428 	if (atomic_inc_return(&server->active) == 1)
429 		atomic_inc(&sb->s_active);
430 }
431 
432 void nfs_sb_deactive(struct super_block *sb)
433 {
434 	struct nfs_server *server = NFS_SB(sb);
435 
436 	if (atomic_dec_and_test(&server->active))
437 		deactivate_super(sb);
438 }
439 
440 /*
441  * Deliver file system statistics to userspace
442  */
443 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
444 {
445 	struct nfs_server *server = NFS_SB(dentry->d_sb);
446 	unsigned char blockbits;
447 	unsigned long blockres;
448 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
449 	struct nfs_fsstat res;
450 	int error = -ENOMEM;
451 
452 	res.fattr = nfs_alloc_fattr();
453 	if (res.fattr == NULL)
454 		goto out_err;
455 
456 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
457 	if (unlikely(error == -ESTALE)) {
458 		struct dentry *pd_dentry;
459 
460 		pd_dentry = dget_parent(dentry);
461 		if (pd_dentry != NULL) {
462 			nfs_zap_caches(pd_dentry->d_inode);
463 			dput(pd_dentry);
464 		}
465 	}
466 	nfs_free_fattr(res.fattr);
467 	if (error < 0)
468 		goto out_err;
469 
470 	buf->f_type = NFS_SUPER_MAGIC;
471 
472 	/*
473 	 * Current versions of glibc do not correctly handle the
474 	 * case where f_frsize != f_bsize.  Eventually we want to
475 	 * report the value of wtmult in this field.
476 	 */
477 	buf->f_frsize = dentry->d_sb->s_blocksize;
478 
479 	/*
480 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
481 	 * are reported in units of f_frsize.  Linux hasn't had
482 	 * an f_frsize field in its statfs struct until recently,
483 	 * thus historically Linux's sys_statfs reports these
484 	 * fields in units of f_bsize.
485 	 */
486 	buf->f_bsize = dentry->d_sb->s_blocksize;
487 	blockbits = dentry->d_sb->s_blocksize_bits;
488 	blockres = (1 << blockbits) - 1;
489 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
490 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
491 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
492 
493 	buf->f_files = res.tfiles;
494 	buf->f_ffree = res.afiles;
495 
496 	buf->f_namelen = server->namelen;
497 
498 	return 0;
499 
500  out_err:
501 	dprintk("%s: statfs error = %d\n", __func__, -error);
502 	return error;
503 }
504 
505 /*
506  * Map the security flavour number to a name
507  */
508 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
509 {
510 	static const struct {
511 		rpc_authflavor_t flavour;
512 		const char *str;
513 	} sec_flavours[] = {
514 		{ RPC_AUTH_NULL, "null" },
515 		{ RPC_AUTH_UNIX, "sys" },
516 		{ RPC_AUTH_GSS_KRB5, "krb5" },
517 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
518 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
519 		{ RPC_AUTH_GSS_LKEY, "lkey" },
520 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
521 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
522 		{ RPC_AUTH_GSS_SPKM, "spkm" },
523 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
524 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
525 		{ UINT_MAX, "unknown" }
526 	};
527 	int i;
528 
529 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
530 		if (sec_flavours[i].flavour == flavour)
531 			break;
532 	}
533 	return sec_flavours[i].str;
534 }
535 
536 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
537 				  int showdefaults)
538 {
539 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
540 
541 	seq_printf(m, ",mountproto=");
542 	switch (sap->sa_family) {
543 	case AF_INET:
544 		switch (nfss->mountd_protocol) {
545 		case IPPROTO_UDP:
546 			seq_printf(m, RPCBIND_NETID_UDP);
547 			break;
548 		case IPPROTO_TCP:
549 			seq_printf(m, RPCBIND_NETID_TCP);
550 			break;
551 		default:
552 			if (showdefaults)
553 				seq_printf(m, "auto");
554 		}
555 		break;
556 	case AF_INET6:
557 		switch (nfss->mountd_protocol) {
558 		case IPPROTO_UDP:
559 			seq_printf(m, RPCBIND_NETID_UDP6);
560 			break;
561 		case IPPROTO_TCP:
562 			seq_printf(m, RPCBIND_NETID_TCP6);
563 			break;
564 		default:
565 			if (showdefaults)
566 				seq_printf(m, "auto");
567 		}
568 		break;
569 	default:
570 		if (showdefaults)
571 			seq_printf(m, "auto");
572 	}
573 }
574 
575 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
576 				    int showdefaults)
577 {
578 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
579 
580 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
581 		return;
582 
583 	switch (sap->sa_family) {
584 	case AF_INET: {
585 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
586 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
587 		break;
588 	}
589 	case AF_INET6: {
590 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
591 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
592 		break;
593 	}
594 	default:
595 		if (showdefaults)
596 			seq_printf(m, ",mountaddr=unspecified");
597 	}
598 
599 	if (nfss->mountd_version || showdefaults)
600 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
601 	if ((nfss->mountd_port &&
602 		nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT) ||
603 		showdefaults)
604 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
605 
606 	nfs_show_mountd_netid(m, nfss, showdefaults);
607 }
608 
609 #ifdef CONFIG_NFS_V4
610 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
611 				    int showdefaults)
612 {
613 	struct nfs_client *clp = nfss->nfs_client;
614 
615 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
616 	seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
617 }
618 #else
619 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
620 				    int showdefaults)
621 {
622 }
623 #endif
624 
625 /*
626  * Describe the mount options in force on this server representation
627  */
628 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
629 				   int showdefaults)
630 {
631 	static const struct proc_nfs_info {
632 		int flag;
633 		const char *str;
634 		const char *nostr;
635 	} nfs_info[] = {
636 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
637 		{ NFS_MOUNT_POSIX, ",posix", "" },
638 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
639 		{ NFS_MOUNT_NOAC, ",noac", "" },
640 		{ NFS_MOUNT_NONLM, ",nolock", "" },
641 		{ NFS_MOUNT_NOACL, ",noacl", "" },
642 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
643 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
644 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
645 		{ 0, NULL, NULL }
646 	};
647 	const struct proc_nfs_info *nfs_infop;
648 	struct nfs_client *clp = nfss->nfs_client;
649 	u32 version = clp->rpc_ops->version;
650 	int local_flock, local_fcntl;
651 
652 	seq_printf(m, ",vers=%u", version);
653 	seq_printf(m, ",rsize=%u", nfss->rsize);
654 	seq_printf(m, ",wsize=%u", nfss->wsize);
655 	if (nfss->bsize != 0)
656 		seq_printf(m, ",bsize=%u", nfss->bsize);
657 	seq_printf(m, ",namlen=%u", nfss->namelen);
658 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
659 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
660 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
661 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
662 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
663 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
664 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
665 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
666 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
667 		if (nfss->flags & nfs_infop->flag)
668 			seq_puts(m, nfs_infop->str);
669 		else
670 			seq_puts(m, nfs_infop->nostr);
671 	}
672 	seq_printf(m, ",proto=%s",
673 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
674 	if (version == 4) {
675 		if (nfss->port != NFS_PORT)
676 			seq_printf(m, ",port=%u", nfss->port);
677 	} else
678 		if (nfss->port)
679 			seq_printf(m, ",port=%u", nfss->port);
680 
681 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
682 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
683 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
684 
685 	if (version != 4)
686 		nfs_show_mountd_options(m, nfss, showdefaults);
687 	else
688 		nfs_show_nfsv4_options(m, nfss, showdefaults);
689 
690 	if (nfss->options & NFS_OPTION_FSCACHE)
691 		seq_printf(m, ",fsc");
692 
693 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
694 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
695 			seq_printf(m, ",lookupcache=none");
696 		else
697 			seq_printf(m, ",lookupcache=pos");
698 	}
699 
700 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
701 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
702 
703 	if (!local_flock && !local_fcntl)
704 		seq_printf(m, ",local_lock=none");
705 	else if (local_flock && local_fcntl)
706 		seq_printf(m, ",local_lock=all");
707 	else if (local_flock)
708 		seq_printf(m, ",local_lock=flock");
709 	else
710 		seq_printf(m, ",local_lock=posix");
711 }
712 
713 /*
714  * Describe the mount options on this VFS mountpoint
715  */
716 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
717 {
718 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
719 
720 	nfs_show_mount_options(m, nfss, 0);
721 
722 	seq_printf(m, ",addr=%s",
723 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
724 							RPC_DISPLAY_ADDR));
725 
726 	return 0;
727 }
728 
729 /*
730  * Present statistical information for this VFS mountpoint
731  */
732 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
733 {
734 	int i, cpu;
735 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
736 	struct rpc_auth *auth = nfss->client->cl_auth;
737 	struct nfs_iostats totals = { };
738 
739 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
740 
741 	/*
742 	 * Display all mount option settings
743 	 */
744 	seq_printf(m, "\n\topts:\t");
745 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
746 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
747 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
748 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
749 	nfs_show_mount_options(m, nfss, 1);
750 
751 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
752 
753 	seq_printf(m, "\n\tcaps:\t");
754 	seq_printf(m, "caps=0x%x", nfss->caps);
755 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
756 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
757 	seq_printf(m, ",bsize=%u", nfss->bsize);
758 	seq_printf(m, ",namlen=%u", nfss->namelen);
759 
760 #ifdef CONFIG_NFS_V4
761 	if (nfss->nfs_client->rpc_ops->version == 4) {
762 		seq_printf(m, "\n\tnfsv4:\t");
763 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
764 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
765 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
766 	}
767 #endif
768 
769 	/*
770 	 * Display security flavor in effect for this mount
771 	 */
772 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
773 	if (auth->au_flavor)
774 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
775 
776 	/*
777 	 * Display superblock I/O counters
778 	 */
779 	for_each_possible_cpu(cpu) {
780 		struct nfs_iostats *stats;
781 
782 		preempt_disable();
783 		stats = per_cpu_ptr(nfss->io_stats, cpu);
784 
785 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
786 			totals.events[i] += stats->events[i];
787 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
788 			totals.bytes[i] += stats->bytes[i];
789 #ifdef CONFIG_NFS_FSCACHE
790 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
791 			totals.fscache[i] += stats->fscache[i];
792 #endif
793 
794 		preempt_enable();
795 	}
796 
797 	seq_printf(m, "\n\tevents:\t");
798 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
799 		seq_printf(m, "%lu ", totals.events[i]);
800 	seq_printf(m, "\n\tbytes:\t");
801 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
802 		seq_printf(m, "%Lu ", totals.bytes[i]);
803 #ifdef CONFIG_NFS_FSCACHE
804 	if (nfss->options & NFS_OPTION_FSCACHE) {
805 		seq_printf(m, "\n\tfsc:\t");
806 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
807 			seq_printf(m, "%Lu ", totals.bytes[i]);
808 	}
809 #endif
810 	seq_printf(m, "\n");
811 
812 	rpc_print_iostats(m, nfss->client);
813 
814 	return 0;
815 }
816 
817 /*
818  * Begin unmount by attempting to remove all automounted mountpoints we added
819  * in response to xdev traversals and referrals
820  */
821 static void nfs_umount_begin(struct super_block *sb)
822 {
823 	struct nfs_server *server;
824 	struct rpc_clnt *rpc;
825 
826 	server = NFS_SB(sb);
827 	/* -EIO all pending I/O */
828 	rpc = server->client_acl;
829 	if (!IS_ERR(rpc))
830 		rpc_killall_tasks(rpc);
831 	rpc = server->client;
832 	if (!IS_ERR(rpc))
833 		rpc_killall_tasks(rpc);
834 }
835 
836 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
837 {
838 	struct nfs_parsed_mount_data *data;
839 
840 	data = kzalloc(sizeof(*data), GFP_KERNEL);
841 	if (data) {
842 		data->acregmin		= NFS_DEF_ACREGMIN;
843 		data->acregmax		= NFS_DEF_ACREGMAX;
844 		data->acdirmin		= NFS_DEF_ACDIRMIN;
845 		data->acdirmax		= NFS_DEF_ACDIRMAX;
846 		data->mount_server.port	= NFS_UNSPEC_PORT;
847 		data->nfs_server.port	= NFS_UNSPEC_PORT;
848 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
849 		data->auth_flavors[0]	= RPC_AUTH_UNIX;
850 		data->auth_flavor_len	= 1;
851 		data->version		= version;
852 		data->minorversion	= 0;
853 	}
854 	return data;
855 }
856 
857 /*
858  * Sanity-check a server address provided by the mount command.
859  *
860  * Address family must be initialized, and address must not be
861  * the ANY address for that family.
862  */
863 static int nfs_verify_server_address(struct sockaddr *addr)
864 {
865 	switch (addr->sa_family) {
866 	case AF_INET: {
867 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
868 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
869 	}
870 	case AF_INET6: {
871 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
872 		return !ipv6_addr_any(sa);
873 	}
874 	}
875 
876 	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
877 	return 0;
878 }
879 
880 /*
881  * Select between a default port value and a user-specified port value.
882  * If a zero value is set, then autobind will be used.
883  */
884 static void nfs_set_port(struct sockaddr *sap, int *port,
885 				 const unsigned short default_port)
886 {
887 	if (*port == NFS_UNSPEC_PORT)
888 		*port = default_port;
889 
890 	rpc_set_port(sap, *port);
891 }
892 
893 /*
894  * Sanity check the NFS transport protocol.
895  *
896  */
897 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
898 {
899 	switch (mnt->nfs_server.protocol) {
900 	case XPRT_TRANSPORT_UDP:
901 	case XPRT_TRANSPORT_TCP:
902 	case XPRT_TRANSPORT_RDMA:
903 		break;
904 	default:
905 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
906 	}
907 }
908 
909 /*
910  * For text based NFSv2/v3 mounts, the mount protocol transport default
911  * settings should depend upon the specified NFS transport.
912  */
913 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
914 {
915 	nfs_validate_transport_protocol(mnt);
916 
917 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
918 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
919 			return;
920 	switch (mnt->nfs_server.protocol) {
921 	case XPRT_TRANSPORT_UDP:
922 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
923 		break;
924 	case XPRT_TRANSPORT_TCP:
925 	case XPRT_TRANSPORT_RDMA:
926 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
927 	}
928 }
929 
930 /*
931  * Parse the value of the 'sec=' option.
932  */
933 static int nfs_parse_security_flavors(char *value,
934 				      struct nfs_parsed_mount_data *mnt)
935 {
936 	substring_t args[MAX_OPT_ARGS];
937 
938 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
939 
940 	switch (match_token(value, nfs_secflavor_tokens, args)) {
941 	case Opt_sec_none:
942 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
943 		break;
944 	case Opt_sec_sys:
945 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
946 		break;
947 	case Opt_sec_krb5:
948 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
949 		break;
950 	case Opt_sec_krb5i:
951 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
952 		break;
953 	case Opt_sec_krb5p:
954 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
955 		break;
956 	case Opt_sec_lkey:
957 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
958 		break;
959 	case Opt_sec_lkeyi:
960 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
961 		break;
962 	case Opt_sec_lkeyp:
963 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
964 		break;
965 	case Opt_sec_spkm:
966 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
967 		break;
968 	case Opt_sec_spkmi:
969 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
970 		break;
971 	case Opt_sec_spkmp:
972 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
973 		break;
974 	default:
975 		return 0;
976 	}
977 
978 	mnt->auth_flavor_len = 1;
979 	return 1;
980 }
981 
982 /*
983  * Error-check and convert a string of mount options from user space into
984  * a data structure.  The whole mount string is processed; bad options are
985  * skipped as they are encountered.  If there were no errors, return 1;
986  * otherwise return 0 (zero).
987  */
988 static int nfs_parse_mount_options(char *raw,
989 				   struct nfs_parsed_mount_data *mnt)
990 {
991 	char *p, *string, *secdata;
992 	int rc, sloppy = 0, invalid_option = 0;
993 	unsigned short protofamily = AF_UNSPEC;
994 	unsigned short mountfamily = AF_UNSPEC;
995 
996 	if (!raw) {
997 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
998 		return 1;
999 	}
1000 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
1001 
1002 	secdata = alloc_secdata();
1003 	if (!secdata)
1004 		goto out_nomem;
1005 
1006 	rc = security_sb_copy_data(raw, secdata);
1007 	if (rc)
1008 		goto out_security_failure;
1009 
1010 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1011 	if (rc)
1012 		goto out_security_failure;
1013 
1014 	free_secdata(secdata);
1015 
1016 	while ((p = strsep(&raw, ",")) != NULL) {
1017 		substring_t args[MAX_OPT_ARGS];
1018 		unsigned long option;
1019 		int token;
1020 
1021 		if (!*p)
1022 			continue;
1023 
1024 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1025 
1026 		token = match_token(p, nfs_mount_option_tokens, args);
1027 		switch (token) {
1028 
1029 		/*
1030 		 * boolean options:  foo/nofoo
1031 		 */
1032 		case Opt_soft:
1033 			mnt->flags |= NFS_MOUNT_SOFT;
1034 			break;
1035 		case Opt_hard:
1036 			mnt->flags &= ~NFS_MOUNT_SOFT;
1037 			break;
1038 		case Opt_posix:
1039 			mnt->flags |= NFS_MOUNT_POSIX;
1040 			break;
1041 		case Opt_noposix:
1042 			mnt->flags &= ~NFS_MOUNT_POSIX;
1043 			break;
1044 		case Opt_cto:
1045 			mnt->flags &= ~NFS_MOUNT_NOCTO;
1046 			break;
1047 		case Opt_nocto:
1048 			mnt->flags |= NFS_MOUNT_NOCTO;
1049 			break;
1050 		case Opt_ac:
1051 			mnt->flags &= ~NFS_MOUNT_NOAC;
1052 			break;
1053 		case Opt_noac:
1054 			mnt->flags |= NFS_MOUNT_NOAC;
1055 			break;
1056 		case Opt_lock:
1057 			mnt->flags &= ~NFS_MOUNT_NONLM;
1058 			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1059 					NFS_MOUNT_LOCAL_FCNTL);
1060 			break;
1061 		case Opt_nolock:
1062 			mnt->flags |= NFS_MOUNT_NONLM;
1063 			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1064 				       NFS_MOUNT_LOCAL_FCNTL);
1065 			break;
1066 		case Opt_v2:
1067 			mnt->flags &= ~NFS_MOUNT_VER3;
1068 			mnt->version = 2;
1069 			break;
1070 		case Opt_v3:
1071 			mnt->flags |= NFS_MOUNT_VER3;
1072 			mnt->version = 3;
1073 			break;
1074 		case Opt_v4:
1075 			mnt->flags &= ~NFS_MOUNT_VER3;
1076 			mnt->version = 4;
1077 			break;
1078 		case Opt_udp:
1079 			mnt->flags &= ~NFS_MOUNT_TCP;
1080 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1081 			break;
1082 		case Opt_tcp:
1083 			mnt->flags |= NFS_MOUNT_TCP;
1084 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1085 			break;
1086 		case Opt_rdma:
1087 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1088 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1089 			xprt_load_transport(p);
1090 			break;
1091 		case Opt_acl:
1092 			mnt->flags &= ~NFS_MOUNT_NOACL;
1093 			break;
1094 		case Opt_noacl:
1095 			mnt->flags |= NFS_MOUNT_NOACL;
1096 			break;
1097 		case Opt_rdirplus:
1098 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1099 			break;
1100 		case Opt_nordirplus:
1101 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1102 			break;
1103 		case Opt_sharecache:
1104 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1105 			break;
1106 		case Opt_nosharecache:
1107 			mnt->flags |= NFS_MOUNT_UNSHARED;
1108 			break;
1109 		case Opt_resvport:
1110 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1111 			break;
1112 		case Opt_noresvport:
1113 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1114 			break;
1115 		case Opt_fscache:
1116 			mnt->options |= NFS_OPTION_FSCACHE;
1117 			kfree(mnt->fscache_uniq);
1118 			mnt->fscache_uniq = NULL;
1119 			break;
1120 		case Opt_nofscache:
1121 			mnt->options &= ~NFS_OPTION_FSCACHE;
1122 			kfree(mnt->fscache_uniq);
1123 			mnt->fscache_uniq = NULL;
1124 			break;
1125 
1126 		/*
1127 		 * options that take numeric values
1128 		 */
1129 		case Opt_port:
1130 			string = match_strdup(args);
1131 			if (string == NULL)
1132 				goto out_nomem;
1133 			rc = strict_strtoul(string, 10, &option);
1134 			kfree(string);
1135 			if (rc != 0 || option > USHRT_MAX)
1136 				goto out_invalid_value;
1137 			mnt->nfs_server.port = option;
1138 			break;
1139 		case Opt_rsize:
1140 			string = match_strdup(args);
1141 			if (string == NULL)
1142 				goto out_nomem;
1143 			rc = strict_strtoul(string, 10, &option);
1144 			kfree(string);
1145 			if (rc != 0)
1146 				goto out_invalid_value;
1147 			mnt->rsize = option;
1148 			break;
1149 		case Opt_wsize:
1150 			string = match_strdup(args);
1151 			if (string == NULL)
1152 				goto out_nomem;
1153 			rc = strict_strtoul(string, 10, &option);
1154 			kfree(string);
1155 			if (rc != 0)
1156 				goto out_invalid_value;
1157 			mnt->wsize = option;
1158 			break;
1159 		case Opt_bsize:
1160 			string = match_strdup(args);
1161 			if (string == NULL)
1162 				goto out_nomem;
1163 			rc = strict_strtoul(string, 10, &option);
1164 			kfree(string);
1165 			if (rc != 0)
1166 				goto out_invalid_value;
1167 			mnt->bsize = option;
1168 			break;
1169 		case Opt_timeo:
1170 			string = match_strdup(args);
1171 			if (string == NULL)
1172 				goto out_nomem;
1173 			rc = strict_strtoul(string, 10, &option);
1174 			kfree(string);
1175 			if (rc != 0 || option == 0)
1176 				goto out_invalid_value;
1177 			mnt->timeo = option;
1178 			break;
1179 		case Opt_retrans:
1180 			string = match_strdup(args);
1181 			if (string == NULL)
1182 				goto out_nomem;
1183 			rc = strict_strtoul(string, 10, &option);
1184 			kfree(string);
1185 			if (rc != 0 || option == 0)
1186 				goto out_invalid_value;
1187 			mnt->retrans = option;
1188 			break;
1189 		case Opt_acregmin:
1190 			string = match_strdup(args);
1191 			if (string == NULL)
1192 				goto out_nomem;
1193 			rc = strict_strtoul(string, 10, &option);
1194 			kfree(string);
1195 			if (rc != 0)
1196 				goto out_invalid_value;
1197 			mnt->acregmin = option;
1198 			break;
1199 		case Opt_acregmax:
1200 			string = match_strdup(args);
1201 			if (string == NULL)
1202 				goto out_nomem;
1203 			rc = strict_strtoul(string, 10, &option);
1204 			kfree(string);
1205 			if (rc != 0)
1206 				goto out_invalid_value;
1207 			mnt->acregmax = option;
1208 			break;
1209 		case Opt_acdirmin:
1210 			string = match_strdup(args);
1211 			if (string == NULL)
1212 				goto out_nomem;
1213 			rc = strict_strtoul(string, 10, &option);
1214 			kfree(string);
1215 			if (rc != 0)
1216 				goto out_invalid_value;
1217 			mnt->acdirmin = option;
1218 			break;
1219 		case Opt_acdirmax:
1220 			string = match_strdup(args);
1221 			if (string == NULL)
1222 				goto out_nomem;
1223 			rc = strict_strtoul(string, 10, &option);
1224 			kfree(string);
1225 			if (rc != 0)
1226 				goto out_invalid_value;
1227 			mnt->acdirmax = option;
1228 			break;
1229 		case Opt_actimeo:
1230 			string = match_strdup(args);
1231 			if (string == NULL)
1232 				goto out_nomem;
1233 			rc = strict_strtoul(string, 10, &option);
1234 			kfree(string);
1235 			if (rc != 0)
1236 				goto out_invalid_value;
1237 			mnt->acregmin = mnt->acregmax =
1238 			mnt->acdirmin = mnt->acdirmax = option;
1239 			break;
1240 		case Opt_namelen:
1241 			string = match_strdup(args);
1242 			if (string == NULL)
1243 				goto out_nomem;
1244 			rc = strict_strtoul(string, 10, &option);
1245 			kfree(string);
1246 			if (rc != 0)
1247 				goto out_invalid_value;
1248 			mnt->namlen = option;
1249 			break;
1250 		case Opt_mountport:
1251 			string = match_strdup(args);
1252 			if (string == NULL)
1253 				goto out_nomem;
1254 			rc = strict_strtoul(string, 10, &option);
1255 			kfree(string);
1256 			if (rc != 0 || option > USHRT_MAX)
1257 				goto out_invalid_value;
1258 			mnt->mount_server.port = option;
1259 			break;
1260 		case Opt_mountvers:
1261 			string = match_strdup(args);
1262 			if (string == NULL)
1263 				goto out_nomem;
1264 			rc = strict_strtoul(string, 10, &option);
1265 			kfree(string);
1266 			if (rc != 0 ||
1267 			    option < NFS_MNT_VERSION ||
1268 			    option > NFS_MNT3_VERSION)
1269 				goto out_invalid_value;
1270 			mnt->mount_server.version = option;
1271 			break;
1272 		case Opt_nfsvers:
1273 			string = match_strdup(args);
1274 			if (string == NULL)
1275 				goto out_nomem;
1276 			rc = strict_strtoul(string, 10, &option);
1277 			kfree(string);
1278 			if (rc != 0)
1279 				goto out_invalid_value;
1280 			switch (option) {
1281 			case NFS2_VERSION:
1282 				mnt->flags &= ~NFS_MOUNT_VER3;
1283 				mnt->version = 2;
1284 				break;
1285 			case NFS3_VERSION:
1286 				mnt->flags |= NFS_MOUNT_VER3;
1287 				mnt->version = 3;
1288 				break;
1289 			case NFS4_VERSION:
1290 				mnt->flags &= ~NFS_MOUNT_VER3;
1291 				mnt->version = 4;
1292 				break;
1293 			default:
1294 				goto out_invalid_value;
1295 			}
1296 			break;
1297 		case Opt_minorversion:
1298 			string = match_strdup(args);
1299 			if (string == NULL)
1300 				goto out_nomem;
1301 			rc = strict_strtoul(string, 10, &option);
1302 			kfree(string);
1303 			if (rc != 0)
1304 				goto out_invalid_value;
1305 			if (option > NFS4_MAX_MINOR_VERSION)
1306 				goto out_invalid_value;
1307 			mnt->minorversion = option;
1308 			break;
1309 
1310 		/*
1311 		 * options that take text values
1312 		 */
1313 		case Opt_sec:
1314 			string = match_strdup(args);
1315 			if (string == NULL)
1316 				goto out_nomem;
1317 			rc = nfs_parse_security_flavors(string, mnt);
1318 			kfree(string);
1319 			if (!rc) {
1320 				dfprintk(MOUNT, "NFS:   unrecognized "
1321 						"security flavor\n");
1322 				return 0;
1323 			}
1324 			break;
1325 		case Opt_proto:
1326 			string = match_strdup(args);
1327 			if (string == NULL)
1328 				goto out_nomem;
1329 			token = match_token(string,
1330 					    nfs_xprt_protocol_tokens, args);
1331 
1332 			protofamily = AF_INET;
1333 			switch (token) {
1334 			case Opt_xprt_udp6:
1335 				protofamily = AF_INET6;
1336 			case Opt_xprt_udp:
1337 				mnt->flags &= ~NFS_MOUNT_TCP;
1338 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1339 				kfree(string);
1340 				break;
1341 			case Opt_xprt_tcp6:
1342 				protofamily = AF_INET6;
1343 			case Opt_xprt_tcp:
1344 				mnt->flags |= NFS_MOUNT_TCP;
1345 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1346 				kfree(string);
1347 				break;
1348 			case Opt_xprt_rdma:
1349 				/* vector side protocols to TCP */
1350 				mnt->flags |= NFS_MOUNT_TCP;
1351 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1352 				xprt_load_transport(string);
1353 				kfree(string);
1354 				break;
1355 			default:
1356 				dfprintk(MOUNT, "NFS:   unrecognized "
1357 						"transport protocol\n");
1358 				kfree(string);
1359 				return 0;
1360 			}
1361 			break;
1362 		case Opt_mountproto:
1363 			string = match_strdup(args);
1364 			if (string == NULL)
1365 				goto out_nomem;
1366 			token = match_token(string,
1367 					    nfs_xprt_protocol_tokens, args);
1368 			kfree(string);
1369 
1370 			mountfamily = AF_INET;
1371 			switch (token) {
1372 			case Opt_xprt_udp6:
1373 				mountfamily = AF_INET6;
1374 			case Opt_xprt_udp:
1375 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1376 				break;
1377 			case Opt_xprt_tcp6:
1378 				mountfamily = AF_INET6;
1379 			case Opt_xprt_tcp:
1380 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1381 				break;
1382 			case Opt_xprt_rdma: /* not used for side protocols */
1383 			default:
1384 				dfprintk(MOUNT, "NFS:   unrecognized "
1385 						"transport protocol\n");
1386 				return 0;
1387 			}
1388 			break;
1389 		case Opt_addr:
1390 			string = match_strdup(args);
1391 			if (string == NULL)
1392 				goto out_nomem;
1393 			mnt->nfs_server.addrlen =
1394 				rpc_pton(string, strlen(string),
1395 					(struct sockaddr *)
1396 					&mnt->nfs_server.address,
1397 					sizeof(mnt->nfs_server.address));
1398 			kfree(string);
1399 			if (mnt->nfs_server.addrlen == 0)
1400 				goto out_invalid_address;
1401 			break;
1402 		case Opt_clientaddr:
1403 			string = match_strdup(args);
1404 			if (string == NULL)
1405 				goto out_nomem;
1406 			kfree(mnt->client_address);
1407 			mnt->client_address = string;
1408 			break;
1409 		case Opt_mounthost:
1410 			string = match_strdup(args);
1411 			if (string == NULL)
1412 				goto out_nomem;
1413 			kfree(mnt->mount_server.hostname);
1414 			mnt->mount_server.hostname = string;
1415 			break;
1416 		case Opt_mountaddr:
1417 			string = match_strdup(args);
1418 			if (string == NULL)
1419 				goto out_nomem;
1420 			mnt->mount_server.addrlen =
1421 				rpc_pton(string, strlen(string),
1422 					(struct sockaddr *)
1423 					&mnt->mount_server.address,
1424 					sizeof(mnt->mount_server.address));
1425 			kfree(string);
1426 			if (mnt->mount_server.addrlen == 0)
1427 				goto out_invalid_address;
1428 			break;
1429 		case Opt_lookupcache:
1430 			string = match_strdup(args);
1431 			if (string == NULL)
1432 				goto out_nomem;
1433 			token = match_token(string,
1434 					nfs_lookupcache_tokens, args);
1435 			kfree(string);
1436 			switch (token) {
1437 				case Opt_lookupcache_all:
1438 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1439 					break;
1440 				case Opt_lookupcache_positive:
1441 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1442 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1443 					break;
1444 				case Opt_lookupcache_none:
1445 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1446 					break;
1447 				default:
1448 					dfprintk(MOUNT, "NFS:   invalid "
1449 							"lookupcache argument\n");
1450 					return 0;
1451 			};
1452 			break;
1453 		case Opt_fscache_uniq:
1454 			string = match_strdup(args);
1455 			if (string == NULL)
1456 				goto out_nomem;
1457 			kfree(mnt->fscache_uniq);
1458 			mnt->fscache_uniq = string;
1459 			mnt->options |= NFS_OPTION_FSCACHE;
1460 			break;
1461 		case Opt_local_lock:
1462 			string = match_strdup(args);
1463 			if (string == NULL)
1464 				goto out_nomem;
1465 			token = match_token(string, nfs_local_lock_tokens,
1466 					args);
1467 			kfree(string);
1468 			switch (token) {
1469 			case Opt_local_lock_all:
1470 				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1471 					       NFS_MOUNT_LOCAL_FCNTL);
1472 				break;
1473 			case Opt_local_lock_flock:
1474 				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1475 				break;
1476 			case Opt_local_lock_posix:
1477 				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1478 				break;
1479 			case Opt_local_lock_none:
1480 				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1481 						NFS_MOUNT_LOCAL_FCNTL);
1482 				break;
1483 			default:
1484 				dfprintk(MOUNT, "NFS:	invalid	"
1485 						"local_lock argument\n");
1486 				return 0;
1487 			};
1488 			break;
1489 
1490 		/*
1491 		 * Special options
1492 		 */
1493 		case Opt_sloppy:
1494 			sloppy = 1;
1495 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1496 			break;
1497 		case Opt_userspace:
1498 		case Opt_deprecated:
1499 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1500 					"'%s'\n", p);
1501 			break;
1502 
1503 		default:
1504 			invalid_option = 1;
1505 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1506 					"'%s'\n", p);
1507 		}
1508 	}
1509 
1510 	if (!sloppy && invalid_option)
1511 		return 0;
1512 
1513 	/*
1514 	 * verify that any proto=/mountproto= options match the address
1515 	 * familiies in the addr=/mountaddr= options.
1516 	 */
1517 	if (protofamily != AF_UNSPEC &&
1518 	    protofamily != mnt->nfs_server.address.ss_family)
1519 		goto out_proto_mismatch;
1520 
1521 	if (mountfamily != AF_UNSPEC) {
1522 		if (mnt->mount_server.addrlen) {
1523 			if (mountfamily != mnt->mount_server.address.ss_family)
1524 				goto out_mountproto_mismatch;
1525 		} else {
1526 			if (mountfamily != mnt->nfs_server.address.ss_family)
1527 				goto out_mountproto_mismatch;
1528 		}
1529 	}
1530 
1531 	return 1;
1532 
1533 out_mountproto_mismatch:
1534 	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1535 			 "option\n");
1536 	return 0;
1537 out_proto_mismatch:
1538 	printk(KERN_INFO "NFS: server address does not match proto= option\n");
1539 	return 0;
1540 out_invalid_address:
1541 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1542 	return 0;
1543 out_invalid_value:
1544 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1545 	return 0;
1546 out_nomem:
1547 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1548 	return 0;
1549 out_security_failure:
1550 	free_secdata(secdata);
1551 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1552 	return 0;
1553 }
1554 
1555 /*
1556  * Match the requested auth flavors with the list returned by
1557  * the server.  Returns zero and sets the mount's authentication
1558  * flavor on success; returns -EACCES if server does not support
1559  * the requested flavor.
1560  */
1561 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1562 			     struct nfs_mount_request *request)
1563 {
1564 	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1565 
1566 	/*
1567 	 * Certain releases of Linux's mountd return an empty
1568 	 * flavor list.  To prevent behavioral regression with
1569 	 * these servers (ie. rejecting mounts that used to
1570 	 * succeed), revert to pre-2.6.32 behavior (no checking)
1571 	 * if the returned flavor list is empty.
1572 	 */
1573 	if (server_authlist_len == 0)
1574 		return 0;
1575 
1576 	/*
1577 	 * We avoid sophisticated negotiating here, as there are
1578 	 * plenty of cases where we can get it wrong, providing
1579 	 * either too little or too much security.
1580 	 *
1581 	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
1582 	 * flavor listed first.  However, some servers list
1583 	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1584 	 * preferred default, in args->auth_flavors[0] if user
1585 	 * didn't specify sec= mount option.
1586 	 */
1587 	for (i = 0; i < args->auth_flavor_len; i++)
1588 		for (j = 0; j < server_authlist_len; j++)
1589 			if (args->auth_flavors[i] == request->auth_flavs[j]) {
1590 				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1591 					request->auth_flavs[j]);
1592 				args->auth_flavors[0] = request->auth_flavs[j];
1593 				return 0;
1594 			}
1595 
1596 	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1597 	nfs_umount(request);
1598 	return -EACCES;
1599 }
1600 
1601 /*
1602  * Use the remote server's MOUNT service to request the NFS file handle
1603  * corresponding to the provided path.
1604  */
1605 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1606 			 struct nfs_fh *root_fh)
1607 {
1608 	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1609 	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1610 	struct nfs_mount_request request = {
1611 		.sap		= (struct sockaddr *)
1612 						&args->mount_server.address,
1613 		.dirpath	= args->nfs_server.export_path,
1614 		.protocol	= args->mount_server.protocol,
1615 		.fh		= root_fh,
1616 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1617 		.auth_flav_len	= &server_authlist_len,
1618 		.auth_flavs	= server_authlist,
1619 	};
1620 	int status;
1621 
1622 	if (args->mount_server.version == 0) {
1623 		switch (args->version) {
1624 			default:
1625 				args->mount_server.version = NFS_MNT3_VERSION;
1626 				break;
1627 			case 2:
1628 				args->mount_server.version = NFS_MNT_VERSION;
1629 		}
1630 	}
1631 	request.version = args->mount_server.version;
1632 
1633 	if (args->mount_server.hostname)
1634 		request.hostname = args->mount_server.hostname;
1635 	else
1636 		request.hostname = args->nfs_server.hostname;
1637 
1638 	/*
1639 	 * Construct the mount server's address.
1640 	 */
1641 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1642 		memcpy(request.sap, &args->nfs_server.address,
1643 		       args->nfs_server.addrlen);
1644 		args->mount_server.addrlen = args->nfs_server.addrlen;
1645 	}
1646 	request.salen = args->mount_server.addrlen;
1647 	nfs_set_port(request.sap, &args->mount_server.port, 0);
1648 
1649 	/*
1650 	 * Now ask the mount server to map our export path
1651 	 * to a file handle.
1652 	 */
1653 	status = nfs_mount(&request);
1654 	if (status != 0) {
1655 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1656 				request.hostname, status);
1657 		return status;
1658 	}
1659 
1660 	/*
1661 	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
1662 	 */
1663 	if (args->mount_server.version != NFS_MNT3_VERSION)
1664 		return 0;
1665 	return nfs_walk_authlist(args, &request);
1666 }
1667 
1668 static int nfs_parse_simple_hostname(const char *dev_name,
1669 				     char **hostname, size_t maxnamlen,
1670 				     char **export_path, size_t maxpathlen)
1671 {
1672 	size_t len;
1673 	char *colon, *comma;
1674 
1675 	colon = strchr(dev_name, ':');
1676 	if (colon == NULL)
1677 		goto out_bad_devname;
1678 
1679 	len = colon - dev_name;
1680 	if (len > maxnamlen)
1681 		goto out_hostname;
1682 
1683 	/* N.B. caller will free nfs_server.hostname in all cases */
1684 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1685 	if (!*hostname)
1686 		goto out_nomem;
1687 
1688 	/* kill possible hostname list: not supported */
1689 	comma = strchr(*hostname, ',');
1690 	if (comma != NULL) {
1691 		if (comma == *hostname)
1692 			goto out_bad_devname;
1693 		*comma = '\0';
1694 	}
1695 
1696 	colon++;
1697 	len = strlen(colon);
1698 	if (len > maxpathlen)
1699 		goto out_path;
1700 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1701 	if (!*export_path)
1702 		goto out_nomem;
1703 
1704 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1705 	return 0;
1706 
1707 out_bad_devname:
1708 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1709 	return -EINVAL;
1710 
1711 out_nomem:
1712 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1713 	return -ENOMEM;
1714 
1715 out_hostname:
1716 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1717 	return -ENAMETOOLONG;
1718 
1719 out_path:
1720 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1721 	return -ENAMETOOLONG;
1722 }
1723 
1724 /*
1725  * Hostname has square brackets around it because it contains one or
1726  * more colons.  We look for the first closing square bracket, and a
1727  * colon must follow it.
1728  */
1729 static int nfs_parse_protected_hostname(const char *dev_name,
1730 					char **hostname, size_t maxnamlen,
1731 					char **export_path, size_t maxpathlen)
1732 {
1733 	size_t len;
1734 	char *start, *end;
1735 
1736 	start = (char *)(dev_name + 1);
1737 
1738 	end = strchr(start, ']');
1739 	if (end == NULL)
1740 		goto out_bad_devname;
1741 	if (*(end + 1) != ':')
1742 		goto out_bad_devname;
1743 
1744 	len = end - start;
1745 	if (len > maxnamlen)
1746 		goto out_hostname;
1747 
1748 	/* N.B. caller will free nfs_server.hostname in all cases */
1749 	*hostname = kstrndup(start, len, GFP_KERNEL);
1750 	if (*hostname == NULL)
1751 		goto out_nomem;
1752 
1753 	end += 2;
1754 	len = strlen(end);
1755 	if (len > maxpathlen)
1756 		goto out_path;
1757 	*export_path = kstrndup(end, len, GFP_KERNEL);
1758 	if (!*export_path)
1759 		goto out_nomem;
1760 
1761 	return 0;
1762 
1763 out_bad_devname:
1764 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1765 	return -EINVAL;
1766 
1767 out_nomem:
1768 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1769 	return -ENOMEM;
1770 
1771 out_hostname:
1772 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1773 	return -ENAMETOOLONG;
1774 
1775 out_path:
1776 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1777 	return -ENAMETOOLONG;
1778 }
1779 
1780 /*
1781  * Split "dev_name" into "hostname:export_path".
1782  *
1783  * The leftmost colon demarks the split between the server's hostname
1784  * and the export path.  If the hostname starts with a left square
1785  * bracket, then it may contain colons.
1786  *
1787  * Note: caller frees hostname and export path, even on error.
1788  */
1789 static int nfs_parse_devname(const char *dev_name,
1790 			     char **hostname, size_t maxnamlen,
1791 			     char **export_path, size_t maxpathlen)
1792 {
1793 	if (*dev_name == '[')
1794 		return nfs_parse_protected_hostname(dev_name,
1795 						    hostname, maxnamlen,
1796 						    export_path, maxpathlen);
1797 
1798 	return nfs_parse_simple_hostname(dev_name,
1799 					 hostname, maxnamlen,
1800 					 export_path, maxpathlen);
1801 }
1802 
1803 /*
1804  * Validate the NFS2/NFS3 mount data
1805  * - fills in the mount root filehandle
1806  *
1807  * For option strings, user space handles the following behaviors:
1808  *
1809  * + DNS: mapping server host name to IP address ("addr=" option)
1810  *
1811  * + failure mode: how to behave if a mount request can't be handled
1812  *   immediately ("fg/bg" option)
1813  *
1814  * + retry: how often to retry a mount request ("retry=" option)
1815  *
1816  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1817  *   mountproto=tcp after mountproto=udp, and so on
1818  */
1819 static int nfs_validate_mount_data(void *options,
1820 				   struct nfs_parsed_mount_data *args,
1821 				   struct nfs_fh *mntfh,
1822 				   const char *dev_name)
1823 {
1824 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1825 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1826 
1827 	if (data == NULL)
1828 		goto out_no_data;
1829 
1830 	switch (data->version) {
1831 	case 1:
1832 		data->namlen = 0;
1833 	case 2:
1834 		data->bsize = 0;
1835 	case 3:
1836 		if (data->flags & NFS_MOUNT_VER3)
1837 			goto out_no_v3;
1838 		data->root.size = NFS2_FHSIZE;
1839 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1840 	case 4:
1841 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1842 			goto out_no_sec;
1843 	case 5:
1844 		memset(data->context, 0, sizeof(data->context));
1845 	case 6:
1846 		if (data->flags & NFS_MOUNT_VER3) {
1847 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1848 				goto out_invalid_fh;
1849 			mntfh->size = data->root.size;
1850 			args->version = 3;
1851 		} else {
1852 			mntfh->size = NFS2_FHSIZE;
1853 			args->version = 2;
1854 		}
1855 
1856 
1857 		memcpy(mntfh->data, data->root.data, mntfh->size);
1858 		if (mntfh->size < sizeof(mntfh->data))
1859 			memset(mntfh->data + mntfh->size, 0,
1860 			       sizeof(mntfh->data) - mntfh->size);
1861 
1862 		/*
1863 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1864 		 * can deal with.
1865 		 */
1866 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1867 		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
1868 		args->rsize		= data->rsize;
1869 		args->wsize		= data->wsize;
1870 		args->timeo		= data->timeo;
1871 		args->retrans		= data->retrans;
1872 		args->acregmin		= data->acregmin;
1873 		args->acregmax		= data->acregmax;
1874 		args->acdirmin		= data->acdirmin;
1875 		args->acdirmax		= data->acdirmax;
1876 
1877 		memcpy(sap, &data->addr, sizeof(data->addr));
1878 		args->nfs_server.addrlen = sizeof(data->addr);
1879 		if (!nfs_verify_server_address(sap))
1880 			goto out_no_address;
1881 
1882 		if (!(data->flags & NFS_MOUNT_TCP))
1883 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1884 		/* N.B. caller will free nfs_server.hostname in all cases */
1885 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1886 		args->namlen		= data->namlen;
1887 		args->bsize		= data->bsize;
1888 
1889 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1890 			args->auth_flavors[0] = data->pseudoflavor;
1891 		if (!args->nfs_server.hostname)
1892 			goto out_nomem;
1893 
1894 		if (!(data->flags & NFS_MOUNT_NONLM))
1895 			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1896 					 NFS_MOUNT_LOCAL_FCNTL);
1897 		else
1898 			args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1899 					NFS_MOUNT_LOCAL_FCNTL);
1900 		/*
1901 		 * The legacy version 6 binary mount data from userspace has a
1902 		 * field used only to transport selinux information into the
1903 		 * the kernel.  To continue to support that functionality we
1904 		 * have a touch of selinux knowledge here in the NFS code. The
1905 		 * userspace code converted context=blah to just blah so we are
1906 		 * converting back to the full string selinux understands.
1907 		 */
1908 		if (data->context[0]){
1909 #ifdef CONFIG_SECURITY_SELINUX
1910 			int rc;
1911 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1912 			if (!opts_str)
1913 				return -ENOMEM;
1914 			strcpy(opts_str, "context=");
1915 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1916 			strcat(opts_str, &data->context[0]);
1917 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1918 			kfree(opts_str);
1919 			if (rc)
1920 				return rc;
1921 #else
1922 			return -EINVAL;
1923 #endif
1924 		}
1925 
1926 		break;
1927 	default: {
1928 		int status;
1929 
1930 		if (nfs_parse_mount_options((char *)options, args) == 0)
1931 			return -EINVAL;
1932 
1933 		if (!nfs_verify_server_address(sap))
1934 			goto out_no_address;
1935 
1936 		if (args->version == 4)
1937 #ifdef CONFIG_NFS_V4
1938 			return nfs4_validate_text_mount_data(options,
1939 							     args, dev_name);
1940 #else
1941 			goto out_v4_not_compiled;
1942 #endif
1943 
1944 		nfs_set_port(sap, &args->nfs_server.port, 0);
1945 
1946 		nfs_set_mount_transport_protocol(args);
1947 
1948 		status = nfs_parse_devname(dev_name,
1949 					   &args->nfs_server.hostname,
1950 					   PAGE_SIZE,
1951 					   &args->nfs_server.export_path,
1952 					   NFS_MAXPATHLEN);
1953 		if (!status)
1954 			status = nfs_try_mount(args, mntfh);
1955 
1956 		kfree(args->nfs_server.export_path);
1957 		args->nfs_server.export_path = NULL;
1958 
1959 		if (status)
1960 			return status;
1961 
1962 		break;
1963 		}
1964 	}
1965 
1966 #ifndef CONFIG_NFS_V3
1967 	if (args->version == 3)
1968 		goto out_v3_not_compiled;
1969 #endif /* !CONFIG_NFS_V3 */
1970 
1971 	return 0;
1972 
1973 out_no_data:
1974 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1975 	return -EINVAL;
1976 
1977 out_no_v3:
1978 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1979 		 data->version);
1980 	return -EINVAL;
1981 
1982 out_no_sec:
1983 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1984 	return -EINVAL;
1985 
1986 #ifndef CONFIG_NFS_V3
1987 out_v3_not_compiled:
1988 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1989 	return -EPROTONOSUPPORT;
1990 #endif /* !CONFIG_NFS_V3 */
1991 
1992 #ifndef CONFIG_NFS_V4
1993 out_v4_not_compiled:
1994 	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1995 	return -EPROTONOSUPPORT;
1996 #endif /* !CONFIG_NFS_V4 */
1997 
1998 out_nomem:
1999 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
2000 	return -ENOMEM;
2001 
2002 out_no_address:
2003 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2004 	return -EINVAL;
2005 
2006 out_invalid_fh:
2007 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2008 	return -EINVAL;
2009 }
2010 
2011 static int
2012 nfs_compare_remount_data(struct nfs_server *nfss,
2013 			 struct nfs_parsed_mount_data *data)
2014 {
2015 	if (data->flags != nfss->flags ||
2016 	    data->rsize != nfss->rsize ||
2017 	    data->wsize != nfss->wsize ||
2018 	    data->retrans != nfss->client->cl_timeout->to_retries ||
2019 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2020 	    data->acregmin != nfss->acregmin / HZ ||
2021 	    data->acregmax != nfss->acregmax / HZ ||
2022 	    data->acdirmin != nfss->acdirmin / HZ ||
2023 	    data->acdirmax != nfss->acdirmax / HZ ||
2024 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2025 	    data->nfs_server.port != nfss->port ||
2026 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2027 	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2028 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
2029 		return -EINVAL;
2030 
2031 	return 0;
2032 }
2033 
2034 static int
2035 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2036 {
2037 	int error;
2038 	struct nfs_server *nfss = sb->s_fs_info;
2039 	struct nfs_parsed_mount_data *data;
2040 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2041 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2042 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2043 
2044 	/*
2045 	 * Userspace mount programs that send binary options generally send
2046 	 * them populated with default values. We have no way to know which
2047 	 * ones were explicitly specified. Fall back to legacy behavior and
2048 	 * just return success.
2049 	 */
2050 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2051 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
2052 					   options->version <= 6))))
2053 		return 0;
2054 
2055 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2056 	if (data == NULL)
2057 		return -ENOMEM;
2058 
2059 	/* fill out struct with values from existing mount */
2060 	data->flags = nfss->flags;
2061 	data->rsize = nfss->rsize;
2062 	data->wsize = nfss->wsize;
2063 	data->retrans = nfss->client->cl_timeout->to_retries;
2064 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2065 	data->acregmin = nfss->acregmin / HZ;
2066 	data->acregmax = nfss->acregmax / HZ;
2067 	data->acdirmin = nfss->acdirmin / HZ;
2068 	data->acdirmax = nfss->acdirmax / HZ;
2069 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2070 	data->nfs_server.port = nfss->port;
2071 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2072 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2073 		data->nfs_server.addrlen);
2074 
2075 	/* overwrite those values with any that were specified */
2076 	error = nfs_parse_mount_options((char *)options, data);
2077 	if (error < 0)
2078 		goto out;
2079 
2080 	/* compare new mount options with old ones */
2081 	error = nfs_compare_remount_data(nfss, data);
2082 out:
2083 	kfree(data);
2084 	return error;
2085 }
2086 
2087 /*
2088  * Initialise the common bits of the superblock
2089  */
2090 static inline void nfs_initialise_sb(struct super_block *sb)
2091 {
2092 	struct nfs_server *server = NFS_SB(sb);
2093 
2094 	sb->s_magic = NFS_SUPER_MAGIC;
2095 
2096 	/* We probably want something more informative here */
2097 	snprintf(sb->s_id, sizeof(sb->s_id),
2098 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2099 
2100 	if (sb->s_blocksize == 0)
2101 		sb->s_blocksize = nfs_block_bits(server->wsize,
2102 						 &sb->s_blocksize_bits);
2103 
2104 	if (server->flags & NFS_MOUNT_NOAC)
2105 		sb->s_flags |= MS_SYNCHRONOUS;
2106 
2107 	sb->s_bdi = &server->backing_dev_info;
2108 
2109 	nfs_super_set_maxbytes(sb, server->maxfilesize);
2110 }
2111 
2112 /*
2113  * Finish setting up an NFS2/3 superblock
2114  */
2115 static void nfs_fill_super(struct super_block *sb,
2116 			   struct nfs_parsed_mount_data *data)
2117 {
2118 	struct nfs_server *server = NFS_SB(sb);
2119 
2120 	sb->s_blocksize_bits = 0;
2121 	sb->s_blocksize = 0;
2122 	if (data->bsize)
2123 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2124 
2125 	if (server->nfs_client->rpc_ops->version == 3) {
2126 		/* The VFS shouldn't apply the umask to mode bits. We will do
2127 		 * so ourselves when necessary.
2128 		 */
2129 		sb->s_flags |= MS_POSIXACL;
2130 		sb->s_time_gran = 1;
2131 	}
2132 
2133 	sb->s_op = &nfs_sops;
2134  	nfs_initialise_sb(sb);
2135 }
2136 
2137 /*
2138  * Finish setting up a cloned NFS2/3 superblock
2139  */
2140 static void nfs_clone_super(struct super_block *sb,
2141 			    const struct super_block *old_sb)
2142 {
2143 	struct nfs_server *server = NFS_SB(sb);
2144 
2145 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2146 	sb->s_blocksize = old_sb->s_blocksize;
2147 	sb->s_maxbytes = old_sb->s_maxbytes;
2148 
2149 	if (server->nfs_client->rpc_ops->version == 3) {
2150 		/* The VFS shouldn't apply the umask to mode bits. We will do
2151 		 * so ourselves when necessary.
2152 		 */
2153 		sb->s_flags |= MS_POSIXACL;
2154 		sb->s_time_gran = 1;
2155 	}
2156 
2157 	sb->s_op = old_sb->s_op;
2158  	nfs_initialise_sb(sb);
2159 }
2160 
2161 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2162 {
2163 	const struct nfs_server *a = s->s_fs_info;
2164 	const struct rpc_clnt *clnt_a = a->client;
2165 	const struct rpc_clnt *clnt_b = b->client;
2166 
2167 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2168 		goto Ebusy;
2169 	if (a->nfs_client != b->nfs_client)
2170 		goto Ebusy;
2171 	if (a->flags != b->flags)
2172 		goto Ebusy;
2173 	if (a->wsize != b->wsize)
2174 		goto Ebusy;
2175 	if (a->rsize != b->rsize)
2176 		goto Ebusy;
2177 	if (a->acregmin != b->acregmin)
2178 		goto Ebusy;
2179 	if (a->acregmax != b->acregmax)
2180 		goto Ebusy;
2181 	if (a->acdirmin != b->acdirmin)
2182 		goto Ebusy;
2183 	if (a->acdirmax != b->acdirmax)
2184 		goto Ebusy;
2185 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2186 		goto Ebusy;
2187 	return 1;
2188 Ebusy:
2189 	return 0;
2190 }
2191 
2192 struct nfs_sb_mountdata {
2193 	struct nfs_server *server;
2194 	int mntflags;
2195 };
2196 
2197 static int nfs_set_super(struct super_block *s, void *data)
2198 {
2199 	struct nfs_sb_mountdata *sb_mntdata = data;
2200 	struct nfs_server *server = sb_mntdata->server;
2201 	int ret;
2202 
2203 	s->s_flags = sb_mntdata->mntflags;
2204 	s->s_fs_info = server;
2205 	s->s_d_op = server->nfs_client->rpc_ops->dentry_ops;
2206 	ret = set_anon_super(s, server);
2207 	if (ret == 0)
2208 		server->s_dev = s->s_dev;
2209 	return ret;
2210 }
2211 
2212 static int nfs_compare_super_address(struct nfs_server *server1,
2213 				     struct nfs_server *server2)
2214 {
2215 	struct sockaddr *sap1, *sap2;
2216 
2217 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2218 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2219 
2220 	if (sap1->sa_family != sap2->sa_family)
2221 		return 0;
2222 
2223 	switch (sap1->sa_family) {
2224 	case AF_INET: {
2225 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2226 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2227 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2228 			return 0;
2229 		if (sin1->sin_port != sin2->sin_port)
2230 			return 0;
2231 		break;
2232 	}
2233 	case AF_INET6: {
2234 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2235 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2236 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2237 			return 0;
2238 		if (sin1->sin6_port != sin2->sin6_port)
2239 			return 0;
2240 		break;
2241 	}
2242 	default:
2243 		return 0;
2244 	}
2245 
2246 	return 1;
2247 }
2248 
2249 static int nfs_compare_super(struct super_block *sb, void *data)
2250 {
2251 	struct nfs_sb_mountdata *sb_mntdata = data;
2252 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2253 	int mntflags = sb_mntdata->mntflags;
2254 
2255 	if (!nfs_compare_super_address(old, server))
2256 		return 0;
2257 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2258 	if (old->flags & NFS_MOUNT_UNSHARED)
2259 		return 0;
2260 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2261 		return 0;
2262 	return nfs_compare_mount_options(sb, server, mntflags);
2263 }
2264 
2265 static int nfs_bdi_register(struct nfs_server *server)
2266 {
2267 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2268 }
2269 
2270 static int nfs_get_sb(struct file_system_type *fs_type,
2271 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2272 {
2273 	struct nfs_server *server = NULL;
2274 	struct super_block *s;
2275 	struct nfs_parsed_mount_data *data;
2276 	struct nfs_fh *mntfh;
2277 	struct dentry *mntroot;
2278 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2279 	struct nfs_sb_mountdata sb_mntdata = {
2280 		.mntflags = flags,
2281 	};
2282 	int error = -ENOMEM;
2283 
2284 	data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2285 	mntfh = nfs_alloc_fhandle();
2286 	if (data == NULL || mntfh == NULL)
2287 		goto out_free_fh;
2288 
2289 	security_init_mnt_opts(&data->lsm_opts);
2290 
2291 	/* Validate the mount data */
2292 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2293 	if (error < 0)
2294 		goto out;
2295 
2296 #ifdef CONFIG_NFS_V4
2297 	if (data->version == 4) {
2298 		error = nfs4_try_mount(flags, dev_name, data, mnt);
2299 		kfree(data->client_address);
2300 		kfree(data->nfs_server.export_path);
2301 		goto out;
2302 	}
2303 #endif	/* CONFIG_NFS_V4 */
2304 
2305 	/* Get a volume representation */
2306 	server = nfs_create_server(data, mntfh);
2307 	if (IS_ERR(server)) {
2308 		error = PTR_ERR(server);
2309 		goto out;
2310 	}
2311 	sb_mntdata.server = server;
2312 
2313 	if (server->flags & NFS_MOUNT_UNSHARED)
2314 		compare_super = NULL;
2315 
2316 	/* Get a superblock - note that we may end up sharing one that already exists */
2317 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2318 	if (IS_ERR(s)) {
2319 		error = PTR_ERR(s);
2320 		goto out_err_nosb;
2321 	}
2322 
2323 	if (s->s_fs_info != server) {
2324 		nfs_free_server(server);
2325 		server = NULL;
2326 	} else {
2327 		error = nfs_bdi_register(server);
2328 		if (error)
2329 			goto error_splat_bdi;
2330 	}
2331 
2332 	if (!s->s_root) {
2333 		/* initial superblock/root creation */
2334 		nfs_fill_super(s, data);
2335 		nfs_fscache_get_super_cookie(
2336 			s, data ? data->fscache_uniq : NULL, NULL);
2337 	}
2338 
2339 	mntroot = nfs_get_root(s, mntfh);
2340 	if (IS_ERR(mntroot)) {
2341 		error = PTR_ERR(mntroot);
2342 		goto error_splat_super;
2343 	}
2344 
2345 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2346 	if (error)
2347 		goto error_splat_root;
2348 
2349 	s->s_flags |= MS_ACTIVE;
2350 	mnt->mnt_sb = s;
2351 	mnt->mnt_root = mntroot;
2352 	error = 0;
2353 
2354 out:
2355 	kfree(data->nfs_server.hostname);
2356 	kfree(data->mount_server.hostname);
2357 	kfree(data->fscache_uniq);
2358 	security_free_mnt_opts(&data->lsm_opts);
2359 out_free_fh:
2360 	nfs_free_fhandle(mntfh);
2361 	kfree(data);
2362 	return error;
2363 
2364 out_err_nosb:
2365 	nfs_free_server(server);
2366 	goto out;
2367 
2368 error_splat_root:
2369 	dput(mntroot);
2370 error_splat_super:
2371 	if (server && !s->s_root)
2372 		bdi_unregister(&server->backing_dev_info);
2373 error_splat_bdi:
2374 	deactivate_locked_super(s);
2375 	goto out;
2376 }
2377 
2378 /*
2379  * Ensure that we unregister the bdi before kill_anon_super
2380  * releases the device name
2381  */
2382 static void nfs_put_super(struct super_block *s)
2383 {
2384 	struct nfs_server *server = NFS_SB(s);
2385 
2386 	bdi_unregister(&server->backing_dev_info);
2387 }
2388 
2389 /*
2390  * Destroy an NFS2/3 superblock
2391  */
2392 static void nfs_kill_super(struct super_block *s)
2393 {
2394 	struct nfs_server *server = NFS_SB(s);
2395 
2396 	kill_anon_super(s);
2397 	nfs_fscache_release_super_cookie(s);
2398 	nfs_free_server(server);
2399 }
2400 
2401 /*
2402  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2403  */
2404 static struct dentry *
2405 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2406 		const char *dev_name, void *raw_data)
2407 {
2408 	struct nfs_clone_mount *data = raw_data;
2409 	struct super_block *s;
2410 	struct nfs_server *server;
2411 	struct dentry *mntroot;
2412 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2413 	struct nfs_sb_mountdata sb_mntdata = {
2414 		.mntflags = flags,
2415 	};
2416 	int error;
2417 
2418 	dprintk("--> nfs_xdev_mount()\n");
2419 
2420 	/* create a new volume representation */
2421 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2422 	if (IS_ERR(server)) {
2423 		error = PTR_ERR(server);
2424 		goto out_err_noserver;
2425 	}
2426 	sb_mntdata.server = server;
2427 
2428 	if (server->flags & NFS_MOUNT_UNSHARED)
2429 		compare_super = NULL;
2430 
2431 	/* Get a superblock - note that we may end up sharing one that already exists */
2432 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2433 	if (IS_ERR(s)) {
2434 		error = PTR_ERR(s);
2435 		goto out_err_nosb;
2436 	}
2437 
2438 	if (s->s_fs_info != server) {
2439 		nfs_free_server(server);
2440 		server = NULL;
2441 	} else {
2442 		error = nfs_bdi_register(server);
2443 		if (error)
2444 			goto error_splat_bdi;
2445 	}
2446 
2447 	if (!s->s_root) {
2448 		/* initial superblock/root creation */
2449 		nfs_clone_super(s, data->sb);
2450 		nfs_fscache_get_super_cookie(s, NULL, data);
2451 	}
2452 
2453 	mntroot = nfs_get_root(s, data->fh);
2454 	if (IS_ERR(mntroot)) {
2455 		error = PTR_ERR(mntroot);
2456 		goto error_splat_super;
2457 	}
2458 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2459 		dput(mntroot);
2460 		error = -ESTALE;
2461 		goto error_splat_super;
2462 	}
2463 
2464 	s->s_flags |= MS_ACTIVE;
2465 
2466 	/* clone any lsm security options from the parent to the new sb */
2467 	security_sb_clone_mnt_opts(data->sb, s);
2468 
2469 	dprintk("<-- nfs_xdev_mount() = 0\n");
2470 	return mntroot;
2471 
2472 out_err_nosb:
2473 	nfs_free_server(server);
2474 out_err_noserver:
2475 	dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2476 	return ERR_PTR(error);
2477 
2478 error_splat_super:
2479 	if (server && !s->s_root)
2480 		bdi_unregister(&server->backing_dev_info);
2481 error_splat_bdi:
2482 	deactivate_locked_super(s);
2483 	dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2484 	return ERR_PTR(error);
2485 }
2486 
2487 #ifdef CONFIG_NFS_V4
2488 
2489 /*
2490  * Finish setting up a cloned NFS4 superblock
2491  */
2492 static void nfs4_clone_super(struct super_block *sb,
2493 			    const struct super_block *old_sb)
2494 {
2495 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2496 	sb->s_blocksize = old_sb->s_blocksize;
2497 	sb->s_maxbytes = old_sb->s_maxbytes;
2498 	sb->s_time_gran = 1;
2499 	sb->s_op = old_sb->s_op;
2500 	/*
2501 	 * The VFS shouldn't apply the umask to mode bits. We will do
2502 	 * so ourselves when necessary.
2503 	 */
2504 	sb->s_flags  |= MS_POSIXACL;
2505 	sb->s_xattr  = old_sb->s_xattr;
2506 	nfs_initialise_sb(sb);
2507 }
2508 
2509 /*
2510  * Set up an NFS4 superblock
2511  */
2512 static void nfs4_fill_super(struct super_block *sb)
2513 {
2514 	sb->s_time_gran = 1;
2515 	sb->s_op = &nfs4_sops;
2516 	/*
2517 	 * The VFS shouldn't apply the umask to mode bits. We will do
2518 	 * so ourselves when necessary.
2519 	 */
2520 	sb->s_flags  |= MS_POSIXACL;
2521 	sb->s_xattr = nfs4_xattr_handlers;
2522 	nfs_initialise_sb(sb);
2523 }
2524 
2525 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2526 {
2527 	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2528 			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2529 }
2530 
2531 static int nfs4_validate_text_mount_data(void *options,
2532 					 struct nfs_parsed_mount_data *args,
2533 					 const char *dev_name)
2534 {
2535 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2536 
2537 	nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2538 
2539 	nfs_validate_transport_protocol(args);
2540 
2541 	nfs4_validate_mount_flags(args);
2542 
2543 	if (args->version != 4) {
2544 		dfprintk(MOUNT,
2545 			 "NFS4: Illegal mount version\n");
2546 		return -EINVAL;
2547 	}
2548 
2549 	if (args->auth_flavor_len > 1) {
2550 		dfprintk(MOUNT,
2551 			 "NFS4: Too many RPC auth flavours specified\n");
2552 		return -EINVAL;
2553 	}
2554 
2555 	if (args->client_address == NULL) {
2556 		dfprintk(MOUNT,
2557 			 "NFS4: mount program didn't pass callback address\n");
2558 		return -EINVAL;
2559 	}
2560 
2561 	return nfs_parse_devname(dev_name,
2562 				   &args->nfs_server.hostname,
2563 				   NFS4_MAXNAMLEN,
2564 				   &args->nfs_server.export_path,
2565 				   NFS4_MAXPATHLEN);
2566 }
2567 
2568 /*
2569  * Validate NFSv4 mount options
2570  */
2571 static int nfs4_validate_mount_data(void *options,
2572 				    struct nfs_parsed_mount_data *args,
2573 				    const char *dev_name)
2574 {
2575 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2576 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2577 	char *c;
2578 
2579 	if (data == NULL)
2580 		goto out_no_data;
2581 
2582 	switch (data->version) {
2583 	case 1:
2584 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2585 			goto out_no_address;
2586 		if (data->host_addrlen == 0)
2587 			goto out_no_address;
2588 		args->nfs_server.addrlen = data->host_addrlen;
2589 		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2590 			return -EFAULT;
2591 		if (!nfs_verify_server_address(sap))
2592 			goto out_no_address;
2593 
2594 		if (data->auth_flavourlen) {
2595 			if (data->auth_flavourlen > 1)
2596 				goto out_inval_auth;
2597 			if (copy_from_user(&args->auth_flavors[0],
2598 					   data->auth_flavours,
2599 					   sizeof(args->auth_flavors[0])))
2600 				return -EFAULT;
2601 		}
2602 
2603 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2604 		if (IS_ERR(c))
2605 			return PTR_ERR(c);
2606 		args->nfs_server.hostname = c;
2607 
2608 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2609 		if (IS_ERR(c))
2610 			return PTR_ERR(c);
2611 		args->nfs_server.export_path = c;
2612 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2613 
2614 		c = strndup_user(data->client_addr.data, 16);
2615 		if (IS_ERR(c))
2616 			return PTR_ERR(c);
2617 		args->client_address = c;
2618 
2619 		/*
2620 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2621 		 * can deal with.
2622 		 */
2623 
2624 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2625 		args->rsize	= data->rsize;
2626 		args->wsize	= data->wsize;
2627 		args->timeo	= data->timeo;
2628 		args->retrans	= data->retrans;
2629 		args->acregmin	= data->acregmin;
2630 		args->acregmax	= data->acregmax;
2631 		args->acdirmin	= data->acdirmin;
2632 		args->acdirmax	= data->acdirmax;
2633 		args->nfs_server.protocol = data->proto;
2634 		nfs_validate_transport_protocol(args);
2635 
2636 		break;
2637 	default:
2638 		if (nfs_parse_mount_options((char *)options, args) == 0)
2639 			return -EINVAL;
2640 
2641 		if (!nfs_verify_server_address(sap))
2642 			return -EINVAL;
2643 
2644 		return nfs4_validate_text_mount_data(options, args, dev_name);
2645 	}
2646 
2647 	return 0;
2648 
2649 out_no_data:
2650 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2651 	return -EINVAL;
2652 
2653 out_inval_auth:
2654 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2655 		 data->auth_flavourlen);
2656 	return -EINVAL;
2657 
2658 out_no_address:
2659 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2660 	return -EINVAL;
2661 }
2662 
2663 /*
2664  * Get the superblock for the NFS4 root partition
2665  */
2666 static struct dentry *
2667 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2668 		  const char *dev_name, void *raw_data)
2669 {
2670 	struct nfs_parsed_mount_data *data = raw_data;
2671 	struct super_block *s;
2672 	struct nfs_server *server;
2673 	struct nfs_fh *mntfh;
2674 	struct dentry *mntroot;
2675 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2676 	struct nfs_sb_mountdata sb_mntdata = {
2677 		.mntflags = flags,
2678 	};
2679 	int error = -ENOMEM;
2680 
2681 	mntfh = nfs_alloc_fhandle();
2682 	if (data == NULL || mntfh == NULL)
2683 		goto out_free_fh;
2684 
2685 	security_init_mnt_opts(&data->lsm_opts);
2686 
2687 	/* Get a volume representation */
2688 	server = nfs4_create_server(data, mntfh);
2689 	if (IS_ERR(server)) {
2690 		error = PTR_ERR(server);
2691 		goto out;
2692 	}
2693 	sb_mntdata.server = server;
2694 
2695 	if (server->flags & NFS4_MOUNT_UNSHARED)
2696 		compare_super = NULL;
2697 
2698 	/* Get a superblock - note that we may end up sharing one that already exists */
2699 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2700 	if (IS_ERR(s)) {
2701 		error = PTR_ERR(s);
2702 		goto out_free;
2703 	}
2704 
2705 	if (s->s_fs_info != server) {
2706 		nfs_free_server(server);
2707 		server = NULL;
2708 	} else {
2709 		error = nfs_bdi_register(server);
2710 		if (error)
2711 			goto error_splat_bdi;
2712 	}
2713 
2714 	if (!s->s_root) {
2715 		/* initial superblock/root creation */
2716 		nfs4_fill_super(s);
2717 		nfs_fscache_get_super_cookie(
2718 			s, data ? data->fscache_uniq : NULL, NULL);
2719 	}
2720 
2721 	mntroot = nfs4_get_root(s, mntfh);
2722 	if (IS_ERR(mntroot)) {
2723 		error = PTR_ERR(mntroot);
2724 		goto error_splat_super;
2725 	}
2726 
2727 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2728 	if (error)
2729 		goto error_splat_root;
2730 
2731 	s->s_flags |= MS_ACTIVE;
2732 
2733 	security_free_mnt_opts(&data->lsm_opts);
2734 	nfs_free_fhandle(mntfh);
2735 	return mntroot;
2736 
2737 out:
2738 	security_free_mnt_opts(&data->lsm_opts);
2739 out_free_fh:
2740 	nfs_free_fhandle(mntfh);
2741 	return ERR_PTR(error);
2742 
2743 out_free:
2744 	nfs_free_server(server);
2745 	goto out;
2746 
2747 error_splat_root:
2748 	dput(mntroot);
2749 error_splat_super:
2750 	if (server && !s->s_root)
2751 		bdi_unregister(&server->backing_dev_info);
2752 error_splat_bdi:
2753 	deactivate_locked_super(s);
2754 	goto out;
2755 }
2756 
2757 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2758 		int flags, void *data, const char *hostname)
2759 {
2760 	struct vfsmount *root_mnt;
2761 	char *root_devname;
2762 	size_t len;
2763 
2764 	len = strlen(hostname) + 3;
2765 	root_devname = kmalloc(len, GFP_KERNEL);
2766 	if (root_devname == NULL)
2767 		return ERR_PTR(-ENOMEM);
2768 	snprintf(root_devname, len, "%s:/", hostname);
2769 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2770 	kfree(root_devname);
2771 	return root_mnt;
2772 }
2773 
2774 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2775 {
2776 	char *page = (char *) __get_free_page(GFP_KERNEL);
2777 	char *devname, *tmp;
2778 
2779 	if (page == NULL)
2780 		return;
2781 	devname = nfs_path(path->mnt->mnt_devname,
2782 			path->mnt->mnt_root, path->dentry,
2783 			page, PAGE_SIZE);
2784 	if (IS_ERR(devname))
2785 		goto out_freepage;
2786 	tmp = kstrdup(devname, GFP_KERNEL);
2787 	if (tmp == NULL)
2788 		goto out_freepage;
2789 	kfree(mnt->mnt_devname);
2790 	mnt->mnt_devname = tmp;
2791 out_freepage:
2792 	free_page((unsigned long)page);
2793 }
2794 
2795 struct nfs_referral_count {
2796 	struct list_head list;
2797 	const struct task_struct *task;
2798 	unsigned int referral_count;
2799 };
2800 
2801 static LIST_HEAD(nfs_referral_count_list);
2802 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2803 
2804 static struct nfs_referral_count *nfs_find_referral_count(void)
2805 {
2806 	struct nfs_referral_count *p;
2807 
2808 	list_for_each_entry(p, &nfs_referral_count_list, list) {
2809 		if (p->task == current)
2810 			return p;
2811 	}
2812 	return NULL;
2813 }
2814 
2815 #define NFS_MAX_NESTED_REFERRALS 2
2816 
2817 static int nfs_referral_loop_protect(void)
2818 {
2819 	struct nfs_referral_count *p, *new;
2820 	int ret = -ENOMEM;
2821 
2822 	new = kmalloc(sizeof(*new), GFP_KERNEL);
2823 	if (!new)
2824 		goto out;
2825 	new->task = current;
2826 	new->referral_count = 1;
2827 
2828 	ret = 0;
2829 	spin_lock(&nfs_referral_count_list_lock);
2830 	p = nfs_find_referral_count();
2831 	if (p != NULL) {
2832 		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2833 			ret = -ELOOP;
2834 		else
2835 			p->referral_count++;
2836 	} else {
2837 		list_add(&new->list, &nfs_referral_count_list);
2838 		new = NULL;
2839 	}
2840 	spin_unlock(&nfs_referral_count_list_lock);
2841 	kfree(new);
2842 out:
2843 	return ret;
2844 }
2845 
2846 static void nfs_referral_loop_unprotect(void)
2847 {
2848 	struct nfs_referral_count *p;
2849 
2850 	spin_lock(&nfs_referral_count_list_lock);
2851 	p = nfs_find_referral_count();
2852 	p->referral_count--;
2853 	if (p->referral_count == 0)
2854 		list_del(&p->list);
2855 	else
2856 		p = NULL;
2857 	spin_unlock(&nfs_referral_count_list_lock);
2858 	kfree(p);
2859 }
2860 
2861 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2862 		const char *export_path, struct vfsmount *mnt_target)
2863 {
2864 	struct nameidata *nd = NULL;
2865 	struct mnt_namespace *ns_private;
2866 	struct super_block *s;
2867 	int ret;
2868 
2869 	nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2870 	if (nd == NULL)
2871 		return -ENOMEM;
2872 
2873 	ns_private = create_mnt_ns(root_mnt);
2874 	ret = PTR_ERR(ns_private);
2875 	if (IS_ERR(ns_private))
2876 		goto out_mntput;
2877 
2878 	ret = nfs_referral_loop_protect();
2879 	if (ret != 0)
2880 		goto out_put_mnt_ns;
2881 
2882 	ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2883 			export_path, LOOKUP_FOLLOW, nd);
2884 
2885 	nfs_referral_loop_unprotect();
2886 	put_mnt_ns(ns_private);
2887 
2888 	if (ret != 0)
2889 		goto out_err;
2890 
2891 	s = nd->path.mnt->mnt_sb;
2892 	atomic_inc(&s->s_active);
2893 	mnt_target->mnt_sb = s;
2894 	mnt_target->mnt_root = dget(nd->path.dentry);
2895 
2896 	/* Correct the device pathname */
2897 	nfs_fix_devname(&nd->path, mnt_target);
2898 
2899 	path_put(&nd->path);
2900 	kfree(nd);
2901 	down_write(&s->s_umount);
2902 	return 0;
2903 out_put_mnt_ns:
2904 	put_mnt_ns(ns_private);
2905 out_mntput:
2906 	mntput(root_mnt);
2907 out_err:
2908 	kfree(nd);
2909 	return ret;
2910 }
2911 
2912 static int nfs4_try_mount(int flags, const char *dev_name,
2913 			 struct nfs_parsed_mount_data *data,
2914 			 struct vfsmount *mnt)
2915 {
2916 	char *export_path;
2917 	struct vfsmount *root_mnt;
2918 	int error;
2919 
2920 	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2921 
2922 	export_path = data->nfs_server.export_path;
2923 	data->nfs_server.export_path = "/";
2924 	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2925 			data->nfs_server.hostname);
2926 	data->nfs_server.export_path = export_path;
2927 
2928 	error = PTR_ERR(root_mnt);
2929 	if (IS_ERR(root_mnt))
2930 		goto out;
2931 
2932 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2933 
2934 out:
2935 	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2936 			error != 0 ? " [error]" : "");
2937 	return error;
2938 }
2939 
2940 /*
2941  * Get the superblock for an NFS4 mountpoint
2942  */
2943 static int nfs4_get_sb(struct file_system_type *fs_type,
2944 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2945 {
2946 	struct nfs_parsed_mount_data *data;
2947 	int error = -ENOMEM;
2948 
2949 	data = nfs_alloc_parsed_mount_data(4);
2950 	if (data == NULL)
2951 		goto out_free_data;
2952 
2953 	/* Validate the mount data */
2954 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2955 	if (error < 0)
2956 		goto out;
2957 
2958 	error = nfs4_try_mount(flags, dev_name, data, mnt);
2959 
2960 out:
2961 	kfree(data->client_address);
2962 	kfree(data->nfs_server.export_path);
2963 	kfree(data->nfs_server.hostname);
2964 	kfree(data->fscache_uniq);
2965 out_free_data:
2966 	kfree(data);
2967 	dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2968 			error != 0 ? " [error]" : "");
2969 	return error;
2970 }
2971 
2972 static void nfs4_kill_super(struct super_block *sb)
2973 {
2974 	struct nfs_server *server = NFS_SB(sb);
2975 
2976 	dprintk("--> %s\n", __func__);
2977 	nfs_super_return_all_delegations(sb);
2978 	kill_anon_super(sb);
2979 	nfs_fscache_release_super_cookie(sb);
2980 	nfs_free_server(server);
2981 	dprintk("<-- %s\n", __func__);
2982 }
2983 
2984 /*
2985  * Clone an NFS4 server record on xdev traversal (FSID-change)
2986  */
2987 static struct dentry *
2988 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2989 		 const char *dev_name, void *raw_data)
2990 {
2991 	struct nfs_clone_mount *data = raw_data;
2992 	struct super_block *s;
2993 	struct nfs_server *server;
2994 	struct dentry *mntroot;
2995 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2996 	struct nfs_sb_mountdata sb_mntdata = {
2997 		.mntflags = flags,
2998 	};
2999 	int error;
3000 
3001 	dprintk("--> nfs4_xdev_mount()\n");
3002 
3003 	/* create a new volume representation */
3004 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
3005 	if (IS_ERR(server)) {
3006 		error = PTR_ERR(server);
3007 		goto out_err_noserver;
3008 	}
3009 	sb_mntdata.server = server;
3010 
3011 	if (server->flags & NFS4_MOUNT_UNSHARED)
3012 		compare_super = NULL;
3013 
3014 	/* Get a superblock - note that we may end up sharing one that already exists */
3015 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3016 	if (IS_ERR(s)) {
3017 		error = PTR_ERR(s);
3018 		goto out_err_nosb;
3019 	}
3020 
3021 	if (s->s_fs_info != server) {
3022 		nfs_free_server(server);
3023 		server = NULL;
3024 	} else {
3025 		error = nfs_bdi_register(server);
3026 		if (error)
3027 			goto error_splat_bdi;
3028 	}
3029 
3030 	if (!s->s_root) {
3031 		/* initial superblock/root creation */
3032 		nfs4_clone_super(s, data->sb);
3033 		nfs_fscache_get_super_cookie(s, NULL, data);
3034 	}
3035 
3036 	mntroot = nfs4_get_root(s, data->fh);
3037 	if (IS_ERR(mntroot)) {
3038 		error = PTR_ERR(mntroot);
3039 		goto error_splat_super;
3040 	}
3041 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3042 		dput(mntroot);
3043 		error = -ESTALE;
3044 		goto error_splat_super;
3045 	}
3046 
3047 	s->s_flags |= MS_ACTIVE;
3048 
3049 	security_sb_clone_mnt_opts(data->sb, s);
3050 
3051 	dprintk("<-- nfs4_xdev_mount() = 0\n");
3052 	return mntroot;
3053 
3054 out_err_nosb:
3055 	nfs_free_server(server);
3056 out_err_noserver:
3057 	dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3058 	return ERR_PTR(error);
3059 
3060 error_splat_super:
3061 	if (server && !s->s_root)
3062 		bdi_unregister(&server->backing_dev_info);
3063 error_splat_bdi:
3064 	deactivate_locked_super(s);
3065 	dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3066 	return ERR_PTR(error);
3067 }
3068 
3069 static struct dentry *
3070 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3071 			   const char *dev_name, void *raw_data)
3072 {
3073 	struct nfs_clone_mount *data = raw_data;
3074 	struct super_block *s;
3075 	struct nfs_server *server;
3076 	struct dentry *mntroot;
3077 	struct nfs_fh *mntfh;
3078 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3079 	struct nfs_sb_mountdata sb_mntdata = {
3080 		.mntflags = flags,
3081 	};
3082 	int error = -ENOMEM;
3083 
3084 	dprintk("--> nfs4_referral_get_sb()\n");
3085 
3086 	mntfh = nfs_alloc_fhandle();
3087 	if (mntfh == NULL)
3088 		goto out_err_nofh;
3089 
3090 	/* create a new volume representation */
3091 	server = nfs4_create_referral_server(data, mntfh);
3092 	if (IS_ERR(server)) {
3093 		error = PTR_ERR(server);
3094 		goto out_err_noserver;
3095 	}
3096 	sb_mntdata.server = server;
3097 
3098 	if (server->flags & NFS4_MOUNT_UNSHARED)
3099 		compare_super = NULL;
3100 
3101 	/* Get a superblock - note that we may end up sharing one that already exists */
3102 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3103 	if (IS_ERR(s)) {
3104 		error = PTR_ERR(s);
3105 		goto out_err_nosb;
3106 	}
3107 
3108 	if (s->s_fs_info != server) {
3109 		nfs_free_server(server);
3110 		server = NULL;
3111 	} else {
3112 		error = nfs_bdi_register(server);
3113 		if (error)
3114 			goto error_splat_bdi;
3115 	}
3116 
3117 	if (!s->s_root) {
3118 		/* initial superblock/root creation */
3119 		nfs4_fill_super(s);
3120 		nfs_fscache_get_super_cookie(s, NULL, data);
3121 	}
3122 
3123 	mntroot = nfs4_get_root(s, mntfh);
3124 	if (IS_ERR(mntroot)) {
3125 		error = PTR_ERR(mntroot);
3126 		goto error_splat_super;
3127 	}
3128 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3129 		dput(mntroot);
3130 		error = -ESTALE;
3131 		goto error_splat_super;
3132 	}
3133 
3134 	s->s_flags |= MS_ACTIVE;
3135 
3136 	security_sb_clone_mnt_opts(data->sb, s);
3137 
3138 	nfs_free_fhandle(mntfh);
3139 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
3140 	return mntroot;
3141 
3142 out_err_nosb:
3143 	nfs_free_server(server);
3144 out_err_noserver:
3145 	nfs_free_fhandle(mntfh);
3146 out_err_nofh:
3147 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3148 	return ERR_PTR(error);
3149 
3150 error_splat_super:
3151 	if (server && !s->s_root)
3152 		bdi_unregister(&server->backing_dev_info);
3153 error_splat_bdi:
3154 	deactivate_locked_super(s);
3155 	nfs_free_fhandle(mntfh);
3156 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3157 	return ERR_PTR(error);
3158 }
3159 
3160 /*
3161  * Create an NFS4 server record on referral traversal
3162  */
3163 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3164 		int flags, const char *dev_name, void *raw_data,
3165 		struct vfsmount *mnt)
3166 {
3167 	struct nfs_clone_mount *data = raw_data;
3168 	char *export_path;
3169 	struct vfsmount *root_mnt;
3170 	int error;
3171 
3172 	dprintk("--> nfs4_referral_get_sb()\n");
3173 
3174 	export_path = data->mnt_path;
3175 	data->mnt_path = "/";
3176 
3177 	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3178 			flags, data, data->hostname);
3179 	data->mnt_path = export_path;
3180 
3181 	error = PTR_ERR(root_mnt);
3182 	if (IS_ERR(root_mnt))
3183 		goto out;
3184 
3185 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3186 out:
3187 	dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3188 			error != 0 ? " [error]" : "");
3189 	return error;
3190 }
3191 
3192 #endif /* CONFIG_NFS_V4 */
3193