xref: /openbmc/linux/fs/nfs/super.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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 || showdefaults)
602 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
603 
604 	nfs_show_mountd_netid(m, nfss, showdefaults);
605 }
606 
607 #ifdef CONFIG_NFS_V4
608 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
609 				    int showdefaults)
610 {
611 	struct nfs_client *clp = nfss->nfs_client;
612 
613 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
614 	seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
615 }
616 #else
617 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
618 				    int showdefaults)
619 {
620 }
621 #endif
622 
623 /*
624  * Describe the mount options in force on this server representation
625  */
626 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
627 				   int showdefaults)
628 {
629 	static const struct proc_nfs_info {
630 		int flag;
631 		const char *str;
632 		const char *nostr;
633 	} nfs_info[] = {
634 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
635 		{ NFS_MOUNT_POSIX, ",posix", "" },
636 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
637 		{ NFS_MOUNT_NOAC, ",noac", "" },
638 		{ NFS_MOUNT_NONLM, ",nolock", "" },
639 		{ NFS_MOUNT_NOACL, ",noacl", "" },
640 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
641 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
642 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
643 		{ 0, NULL, NULL }
644 	};
645 	const struct proc_nfs_info *nfs_infop;
646 	struct nfs_client *clp = nfss->nfs_client;
647 	u32 version = clp->rpc_ops->version;
648 	int local_flock, local_fcntl;
649 
650 	seq_printf(m, ",vers=%u", version);
651 	seq_printf(m, ",rsize=%u", nfss->rsize);
652 	seq_printf(m, ",wsize=%u", nfss->wsize);
653 	if (nfss->bsize != 0)
654 		seq_printf(m, ",bsize=%u", nfss->bsize);
655 	seq_printf(m, ",namlen=%u", nfss->namelen);
656 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
657 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
658 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
659 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
660 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
661 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
662 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
663 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
664 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
665 		if (nfss->flags & nfs_infop->flag)
666 			seq_puts(m, nfs_infop->str);
667 		else
668 			seq_puts(m, nfs_infop->nostr);
669 	}
670 	seq_printf(m, ",proto=%s",
671 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
672 	if (version == 4) {
673 		if (nfss->port != NFS_PORT)
674 			seq_printf(m, ",port=%u", nfss->port);
675 	} else
676 		if (nfss->port)
677 			seq_printf(m, ",port=%u", nfss->port);
678 
679 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
680 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
681 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
682 
683 	if (version != 4)
684 		nfs_show_mountd_options(m, nfss, showdefaults);
685 	else
686 		nfs_show_nfsv4_options(m, nfss, showdefaults);
687 
688 	if (nfss->options & NFS_OPTION_FSCACHE)
689 		seq_printf(m, ",fsc");
690 
691 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
692 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
693 			seq_printf(m, ",lookupcache=none");
694 		else
695 			seq_printf(m, ",lookupcache=pos");
696 	}
697 
698 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
699 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
700 
701 	if (!local_flock && !local_fcntl)
702 		seq_printf(m, ",local_lock=none");
703 	else if (local_flock && local_fcntl)
704 		seq_printf(m, ",local_lock=all");
705 	else if (local_flock)
706 		seq_printf(m, ",local_lock=flock");
707 	else
708 		seq_printf(m, ",local_lock=posix");
709 }
710 
711 /*
712  * Describe the mount options on this VFS mountpoint
713  */
714 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
715 {
716 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
717 
718 	nfs_show_mount_options(m, nfss, 0);
719 
720 	seq_printf(m, ",addr=%s",
721 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
722 							RPC_DISPLAY_ADDR));
723 
724 	return 0;
725 }
726 
727 /*
728  * Present statistical information for this VFS mountpoint
729  */
730 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
731 {
732 	int i, cpu;
733 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
734 	struct rpc_auth *auth = nfss->client->cl_auth;
735 	struct nfs_iostats totals = { };
736 
737 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
738 
739 	/*
740 	 * Display all mount option settings
741 	 */
742 	seq_printf(m, "\n\topts:\t");
743 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
744 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
745 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
746 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
747 	nfs_show_mount_options(m, nfss, 1);
748 
749 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
750 
751 	seq_printf(m, "\n\tcaps:\t");
752 	seq_printf(m, "caps=0x%x", nfss->caps);
753 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
754 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
755 	seq_printf(m, ",bsize=%u", nfss->bsize);
756 	seq_printf(m, ",namlen=%u", nfss->namelen);
757 
758 #ifdef CONFIG_NFS_V4
759 	if (nfss->nfs_client->rpc_ops->version == 4) {
760 		seq_printf(m, "\n\tnfsv4:\t");
761 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
762 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
763 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
764 	}
765 #endif
766 
767 	/*
768 	 * Display security flavor in effect for this mount
769 	 */
770 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
771 	if (auth->au_flavor)
772 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
773 
774 	/*
775 	 * Display superblock I/O counters
776 	 */
777 	for_each_possible_cpu(cpu) {
778 		struct nfs_iostats *stats;
779 
780 		preempt_disable();
781 		stats = per_cpu_ptr(nfss->io_stats, cpu);
782 
783 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
784 			totals.events[i] += stats->events[i];
785 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
786 			totals.bytes[i] += stats->bytes[i];
787 #ifdef CONFIG_NFS_FSCACHE
788 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
789 			totals.fscache[i] += stats->fscache[i];
790 #endif
791 
792 		preempt_enable();
793 	}
794 
795 	seq_printf(m, "\n\tevents:\t");
796 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
797 		seq_printf(m, "%lu ", totals.events[i]);
798 	seq_printf(m, "\n\tbytes:\t");
799 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
800 		seq_printf(m, "%Lu ", totals.bytes[i]);
801 #ifdef CONFIG_NFS_FSCACHE
802 	if (nfss->options & NFS_OPTION_FSCACHE) {
803 		seq_printf(m, "\n\tfsc:\t");
804 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
805 			seq_printf(m, "%Lu ", totals.bytes[i]);
806 	}
807 #endif
808 	seq_printf(m, "\n");
809 
810 	rpc_print_iostats(m, nfss->client);
811 
812 	return 0;
813 }
814 
815 /*
816  * Begin unmount by attempting to remove all automounted mountpoints we added
817  * in response to xdev traversals and referrals
818  */
819 static void nfs_umount_begin(struct super_block *sb)
820 {
821 	struct nfs_server *server;
822 	struct rpc_clnt *rpc;
823 
824 	server = NFS_SB(sb);
825 	/* -EIO all pending I/O */
826 	rpc = server->client_acl;
827 	if (!IS_ERR(rpc))
828 		rpc_killall_tasks(rpc);
829 	rpc = server->client;
830 	if (!IS_ERR(rpc))
831 		rpc_killall_tasks(rpc);
832 }
833 
834 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
835 {
836 	struct nfs_parsed_mount_data *data;
837 
838 	data = kzalloc(sizeof(*data), GFP_KERNEL);
839 	if (data) {
840 		data->acregmin		= NFS_DEF_ACREGMIN;
841 		data->acregmax		= NFS_DEF_ACREGMAX;
842 		data->acdirmin		= NFS_DEF_ACDIRMIN;
843 		data->acdirmax		= NFS_DEF_ACDIRMAX;
844 		data->mount_server.port	= NFS_UNSPEC_PORT;
845 		data->nfs_server.port	= NFS_UNSPEC_PORT;
846 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
847 		data->auth_flavors[0]	= RPC_AUTH_UNIX;
848 		data->auth_flavor_len	= 1;
849 		data->version		= version;
850 		data->minorversion	= 0;
851 	}
852 	return data;
853 }
854 
855 /*
856  * Sanity-check a server address provided by the mount command.
857  *
858  * Address family must be initialized, and address must not be
859  * the ANY address for that family.
860  */
861 static int nfs_verify_server_address(struct sockaddr *addr)
862 {
863 	switch (addr->sa_family) {
864 	case AF_INET: {
865 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
866 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
867 	}
868 	case AF_INET6: {
869 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
870 		return !ipv6_addr_any(sa);
871 	}
872 	}
873 
874 	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
875 	return 0;
876 }
877 
878 /*
879  * Select between a default port value and a user-specified port value.
880  * If a zero value is set, then autobind will be used.
881  */
882 static void nfs_set_port(struct sockaddr *sap, int *port,
883 				 const unsigned short default_port)
884 {
885 	if (*port == NFS_UNSPEC_PORT)
886 		*port = default_port;
887 
888 	rpc_set_port(sap, *port);
889 }
890 
891 /*
892  * Sanity check the NFS transport protocol.
893  *
894  */
895 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
896 {
897 	switch (mnt->nfs_server.protocol) {
898 	case XPRT_TRANSPORT_UDP:
899 	case XPRT_TRANSPORT_TCP:
900 	case XPRT_TRANSPORT_RDMA:
901 		break;
902 	default:
903 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
904 	}
905 }
906 
907 /*
908  * For text based NFSv2/v3 mounts, the mount protocol transport default
909  * settings should depend upon the specified NFS transport.
910  */
911 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
912 {
913 	nfs_validate_transport_protocol(mnt);
914 
915 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
916 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
917 			return;
918 	switch (mnt->nfs_server.protocol) {
919 	case XPRT_TRANSPORT_UDP:
920 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
921 		break;
922 	case XPRT_TRANSPORT_TCP:
923 	case XPRT_TRANSPORT_RDMA:
924 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
925 	}
926 }
927 
928 /*
929  * Parse the value of the 'sec=' option.
930  */
931 static int nfs_parse_security_flavors(char *value,
932 				      struct nfs_parsed_mount_data *mnt)
933 {
934 	substring_t args[MAX_OPT_ARGS];
935 
936 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
937 
938 	switch (match_token(value, nfs_secflavor_tokens, args)) {
939 	case Opt_sec_none:
940 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
941 		break;
942 	case Opt_sec_sys:
943 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
944 		break;
945 	case Opt_sec_krb5:
946 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
947 		break;
948 	case Opt_sec_krb5i:
949 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
950 		break;
951 	case Opt_sec_krb5p:
952 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
953 		break;
954 	case Opt_sec_lkey:
955 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
956 		break;
957 	case Opt_sec_lkeyi:
958 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
959 		break;
960 	case Opt_sec_lkeyp:
961 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
962 		break;
963 	case Opt_sec_spkm:
964 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
965 		break;
966 	case Opt_sec_spkmi:
967 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
968 		break;
969 	case Opt_sec_spkmp:
970 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
971 		break;
972 	default:
973 		return 0;
974 	}
975 
976 	mnt->auth_flavor_len = 1;
977 	return 1;
978 }
979 
980 /*
981  * Error-check and convert a string of mount options from user space into
982  * a data structure.  The whole mount string is processed; bad options are
983  * skipped as they are encountered.  If there were no errors, return 1;
984  * otherwise return 0 (zero).
985  */
986 static int nfs_parse_mount_options(char *raw,
987 				   struct nfs_parsed_mount_data *mnt)
988 {
989 	char *p, *string, *secdata;
990 	int rc, sloppy = 0, invalid_option = 0;
991 	unsigned short protofamily = AF_UNSPEC;
992 	unsigned short mountfamily = AF_UNSPEC;
993 
994 	if (!raw) {
995 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
996 		return 1;
997 	}
998 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
999 
1000 	secdata = alloc_secdata();
1001 	if (!secdata)
1002 		goto out_nomem;
1003 
1004 	rc = security_sb_copy_data(raw, secdata);
1005 	if (rc)
1006 		goto out_security_failure;
1007 
1008 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1009 	if (rc)
1010 		goto out_security_failure;
1011 
1012 	free_secdata(secdata);
1013 
1014 	while ((p = strsep(&raw, ",")) != NULL) {
1015 		substring_t args[MAX_OPT_ARGS];
1016 		unsigned long option;
1017 		int token;
1018 
1019 		if (!*p)
1020 			continue;
1021 
1022 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1023 
1024 		token = match_token(p, nfs_mount_option_tokens, args);
1025 		switch (token) {
1026 
1027 		/*
1028 		 * boolean options:  foo/nofoo
1029 		 */
1030 		case Opt_soft:
1031 			mnt->flags |= NFS_MOUNT_SOFT;
1032 			break;
1033 		case Opt_hard:
1034 			mnt->flags &= ~NFS_MOUNT_SOFT;
1035 			break;
1036 		case Opt_posix:
1037 			mnt->flags |= NFS_MOUNT_POSIX;
1038 			break;
1039 		case Opt_noposix:
1040 			mnt->flags &= ~NFS_MOUNT_POSIX;
1041 			break;
1042 		case Opt_cto:
1043 			mnt->flags &= ~NFS_MOUNT_NOCTO;
1044 			break;
1045 		case Opt_nocto:
1046 			mnt->flags |= NFS_MOUNT_NOCTO;
1047 			break;
1048 		case Opt_ac:
1049 			mnt->flags &= ~NFS_MOUNT_NOAC;
1050 			break;
1051 		case Opt_noac:
1052 			mnt->flags |= NFS_MOUNT_NOAC;
1053 			break;
1054 		case Opt_lock:
1055 			mnt->flags &= ~NFS_MOUNT_NONLM;
1056 			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1057 					NFS_MOUNT_LOCAL_FCNTL);
1058 			break;
1059 		case Opt_nolock:
1060 			mnt->flags |= NFS_MOUNT_NONLM;
1061 			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1062 				       NFS_MOUNT_LOCAL_FCNTL);
1063 			break;
1064 		case Opt_v2:
1065 			mnt->flags &= ~NFS_MOUNT_VER3;
1066 			mnt->version = 2;
1067 			break;
1068 		case Opt_v3:
1069 			mnt->flags |= NFS_MOUNT_VER3;
1070 			mnt->version = 3;
1071 			break;
1072 		case Opt_v4:
1073 			mnt->flags &= ~NFS_MOUNT_VER3;
1074 			mnt->version = 4;
1075 			break;
1076 		case Opt_udp:
1077 			mnt->flags &= ~NFS_MOUNT_TCP;
1078 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1079 			break;
1080 		case Opt_tcp:
1081 			mnt->flags |= NFS_MOUNT_TCP;
1082 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1083 			break;
1084 		case Opt_rdma:
1085 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1086 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1087 			xprt_load_transport(p);
1088 			break;
1089 		case Opt_acl:
1090 			mnt->flags &= ~NFS_MOUNT_NOACL;
1091 			break;
1092 		case Opt_noacl:
1093 			mnt->flags |= NFS_MOUNT_NOACL;
1094 			break;
1095 		case Opt_rdirplus:
1096 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1097 			break;
1098 		case Opt_nordirplus:
1099 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1100 			break;
1101 		case Opt_sharecache:
1102 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1103 			break;
1104 		case Opt_nosharecache:
1105 			mnt->flags |= NFS_MOUNT_UNSHARED;
1106 			break;
1107 		case Opt_resvport:
1108 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1109 			break;
1110 		case Opt_noresvport:
1111 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1112 			break;
1113 		case Opt_fscache:
1114 			mnt->options |= NFS_OPTION_FSCACHE;
1115 			kfree(mnt->fscache_uniq);
1116 			mnt->fscache_uniq = NULL;
1117 			break;
1118 		case Opt_nofscache:
1119 			mnt->options &= ~NFS_OPTION_FSCACHE;
1120 			kfree(mnt->fscache_uniq);
1121 			mnt->fscache_uniq = NULL;
1122 			break;
1123 
1124 		/*
1125 		 * options that take numeric values
1126 		 */
1127 		case Opt_port:
1128 			string = match_strdup(args);
1129 			if (string == NULL)
1130 				goto out_nomem;
1131 			rc = strict_strtoul(string, 10, &option);
1132 			kfree(string);
1133 			if (rc != 0 || option > USHRT_MAX)
1134 				goto out_invalid_value;
1135 			mnt->nfs_server.port = option;
1136 			break;
1137 		case Opt_rsize:
1138 			string = match_strdup(args);
1139 			if (string == NULL)
1140 				goto out_nomem;
1141 			rc = strict_strtoul(string, 10, &option);
1142 			kfree(string);
1143 			if (rc != 0)
1144 				goto out_invalid_value;
1145 			mnt->rsize = option;
1146 			break;
1147 		case Opt_wsize:
1148 			string = match_strdup(args);
1149 			if (string == NULL)
1150 				goto out_nomem;
1151 			rc = strict_strtoul(string, 10, &option);
1152 			kfree(string);
1153 			if (rc != 0)
1154 				goto out_invalid_value;
1155 			mnt->wsize = option;
1156 			break;
1157 		case Opt_bsize:
1158 			string = match_strdup(args);
1159 			if (string == NULL)
1160 				goto out_nomem;
1161 			rc = strict_strtoul(string, 10, &option);
1162 			kfree(string);
1163 			if (rc != 0)
1164 				goto out_invalid_value;
1165 			mnt->bsize = option;
1166 			break;
1167 		case Opt_timeo:
1168 			string = match_strdup(args);
1169 			if (string == NULL)
1170 				goto out_nomem;
1171 			rc = strict_strtoul(string, 10, &option);
1172 			kfree(string);
1173 			if (rc != 0 || option == 0)
1174 				goto out_invalid_value;
1175 			mnt->timeo = option;
1176 			break;
1177 		case Opt_retrans:
1178 			string = match_strdup(args);
1179 			if (string == NULL)
1180 				goto out_nomem;
1181 			rc = strict_strtoul(string, 10, &option);
1182 			kfree(string);
1183 			if (rc != 0 || option == 0)
1184 				goto out_invalid_value;
1185 			mnt->retrans = option;
1186 			break;
1187 		case Opt_acregmin:
1188 			string = match_strdup(args);
1189 			if (string == NULL)
1190 				goto out_nomem;
1191 			rc = strict_strtoul(string, 10, &option);
1192 			kfree(string);
1193 			if (rc != 0)
1194 				goto out_invalid_value;
1195 			mnt->acregmin = option;
1196 			break;
1197 		case Opt_acregmax:
1198 			string = match_strdup(args);
1199 			if (string == NULL)
1200 				goto out_nomem;
1201 			rc = strict_strtoul(string, 10, &option);
1202 			kfree(string);
1203 			if (rc != 0)
1204 				goto out_invalid_value;
1205 			mnt->acregmax = option;
1206 			break;
1207 		case Opt_acdirmin:
1208 			string = match_strdup(args);
1209 			if (string == NULL)
1210 				goto out_nomem;
1211 			rc = strict_strtoul(string, 10, &option);
1212 			kfree(string);
1213 			if (rc != 0)
1214 				goto out_invalid_value;
1215 			mnt->acdirmin = option;
1216 			break;
1217 		case Opt_acdirmax:
1218 			string = match_strdup(args);
1219 			if (string == NULL)
1220 				goto out_nomem;
1221 			rc = strict_strtoul(string, 10, &option);
1222 			kfree(string);
1223 			if (rc != 0)
1224 				goto out_invalid_value;
1225 			mnt->acdirmax = option;
1226 			break;
1227 		case Opt_actimeo:
1228 			string = match_strdup(args);
1229 			if (string == NULL)
1230 				goto out_nomem;
1231 			rc = strict_strtoul(string, 10, &option);
1232 			kfree(string);
1233 			if (rc != 0)
1234 				goto out_invalid_value;
1235 			mnt->acregmin = mnt->acregmax =
1236 			mnt->acdirmin = mnt->acdirmax = option;
1237 			break;
1238 		case Opt_namelen:
1239 			string = match_strdup(args);
1240 			if (string == NULL)
1241 				goto out_nomem;
1242 			rc = strict_strtoul(string, 10, &option);
1243 			kfree(string);
1244 			if (rc != 0)
1245 				goto out_invalid_value;
1246 			mnt->namlen = option;
1247 			break;
1248 		case Opt_mountport:
1249 			string = match_strdup(args);
1250 			if (string == NULL)
1251 				goto out_nomem;
1252 			rc = strict_strtoul(string, 10, &option);
1253 			kfree(string);
1254 			if (rc != 0 || option > USHRT_MAX)
1255 				goto out_invalid_value;
1256 			mnt->mount_server.port = option;
1257 			break;
1258 		case Opt_mountvers:
1259 			string = match_strdup(args);
1260 			if (string == NULL)
1261 				goto out_nomem;
1262 			rc = strict_strtoul(string, 10, &option);
1263 			kfree(string);
1264 			if (rc != 0 ||
1265 			    option < NFS_MNT_VERSION ||
1266 			    option > NFS_MNT3_VERSION)
1267 				goto out_invalid_value;
1268 			mnt->mount_server.version = option;
1269 			break;
1270 		case Opt_nfsvers:
1271 			string = match_strdup(args);
1272 			if (string == NULL)
1273 				goto out_nomem;
1274 			rc = strict_strtoul(string, 10, &option);
1275 			kfree(string);
1276 			if (rc != 0)
1277 				goto out_invalid_value;
1278 			switch (option) {
1279 			case NFS2_VERSION:
1280 				mnt->flags &= ~NFS_MOUNT_VER3;
1281 				mnt->version = 2;
1282 				break;
1283 			case NFS3_VERSION:
1284 				mnt->flags |= NFS_MOUNT_VER3;
1285 				mnt->version = 3;
1286 				break;
1287 			case NFS4_VERSION:
1288 				mnt->flags &= ~NFS_MOUNT_VER3;
1289 				mnt->version = 4;
1290 				break;
1291 			default:
1292 				goto out_invalid_value;
1293 			}
1294 			break;
1295 		case Opt_minorversion:
1296 			string = match_strdup(args);
1297 			if (string == NULL)
1298 				goto out_nomem;
1299 			rc = strict_strtoul(string, 10, &option);
1300 			kfree(string);
1301 			if (rc != 0)
1302 				goto out_invalid_value;
1303 			if (option > NFS4_MAX_MINOR_VERSION)
1304 				goto out_invalid_value;
1305 			mnt->minorversion = option;
1306 			break;
1307 
1308 		/*
1309 		 * options that take text values
1310 		 */
1311 		case Opt_sec:
1312 			string = match_strdup(args);
1313 			if (string == NULL)
1314 				goto out_nomem;
1315 			rc = nfs_parse_security_flavors(string, mnt);
1316 			kfree(string);
1317 			if (!rc) {
1318 				dfprintk(MOUNT, "NFS:   unrecognized "
1319 						"security flavor\n");
1320 				return 0;
1321 			}
1322 			break;
1323 		case Opt_proto:
1324 			string = match_strdup(args);
1325 			if (string == NULL)
1326 				goto out_nomem;
1327 			token = match_token(string,
1328 					    nfs_xprt_protocol_tokens, args);
1329 
1330 			protofamily = AF_INET;
1331 			switch (token) {
1332 			case Opt_xprt_udp6:
1333 				protofamily = AF_INET6;
1334 			case Opt_xprt_udp:
1335 				mnt->flags &= ~NFS_MOUNT_TCP;
1336 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1337 				kfree(string);
1338 				break;
1339 			case Opt_xprt_tcp6:
1340 				protofamily = AF_INET6;
1341 			case Opt_xprt_tcp:
1342 				mnt->flags |= NFS_MOUNT_TCP;
1343 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1344 				kfree(string);
1345 				break;
1346 			case Opt_xprt_rdma:
1347 				/* vector side protocols to TCP */
1348 				mnt->flags |= NFS_MOUNT_TCP;
1349 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1350 				xprt_load_transport(string);
1351 				kfree(string);
1352 				break;
1353 			default:
1354 				dfprintk(MOUNT, "NFS:   unrecognized "
1355 						"transport protocol\n");
1356 				kfree(string);
1357 				return 0;
1358 			}
1359 			break;
1360 		case Opt_mountproto:
1361 			string = match_strdup(args);
1362 			if (string == NULL)
1363 				goto out_nomem;
1364 			token = match_token(string,
1365 					    nfs_xprt_protocol_tokens, args);
1366 			kfree(string);
1367 
1368 			mountfamily = AF_INET;
1369 			switch (token) {
1370 			case Opt_xprt_udp6:
1371 				mountfamily = AF_INET6;
1372 			case Opt_xprt_udp:
1373 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1374 				break;
1375 			case Opt_xprt_tcp6:
1376 				mountfamily = AF_INET6;
1377 			case Opt_xprt_tcp:
1378 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1379 				break;
1380 			case Opt_xprt_rdma: /* not used for side protocols */
1381 			default:
1382 				dfprintk(MOUNT, "NFS:   unrecognized "
1383 						"transport protocol\n");
1384 				return 0;
1385 			}
1386 			break;
1387 		case Opt_addr:
1388 			string = match_strdup(args);
1389 			if (string == NULL)
1390 				goto out_nomem;
1391 			mnt->nfs_server.addrlen =
1392 				rpc_pton(string, strlen(string),
1393 					(struct sockaddr *)
1394 					&mnt->nfs_server.address,
1395 					sizeof(mnt->nfs_server.address));
1396 			kfree(string);
1397 			if (mnt->nfs_server.addrlen == 0)
1398 				goto out_invalid_address;
1399 			break;
1400 		case Opt_clientaddr:
1401 			string = match_strdup(args);
1402 			if (string == NULL)
1403 				goto out_nomem;
1404 			kfree(mnt->client_address);
1405 			mnt->client_address = string;
1406 			break;
1407 		case Opt_mounthost:
1408 			string = match_strdup(args);
1409 			if (string == NULL)
1410 				goto out_nomem;
1411 			kfree(mnt->mount_server.hostname);
1412 			mnt->mount_server.hostname = string;
1413 			break;
1414 		case Opt_mountaddr:
1415 			string = match_strdup(args);
1416 			if (string == NULL)
1417 				goto out_nomem;
1418 			mnt->mount_server.addrlen =
1419 				rpc_pton(string, strlen(string),
1420 					(struct sockaddr *)
1421 					&mnt->mount_server.address,
1422 					sizeof(mnt->mount_server.address));
1423 			kfree(string);
1424 			if (mnt->mount_server.addrlen == 0)
1425 				goto out_invalid_address;
1426 			break;
1427 		case Opt_lookupcache:
1428 			string = match_strdup(args);
1429 			if (string == NULL)
1430 				goto out_nomem;
1431 			token = match_token(string,
1432 					nfs_lookupcache_tokens, args);
1433 			kfree(string);
1434 			switch (token) {
1435 				case Opt_lookupcache_all:
1436 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1437 					break;
1438 				case Opt_lookupcache_positive:
1439 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1440 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1441 					break;
1442 				case Opt_lookupcache_none:
1443 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1444 					break;
1445 				default:
1446 					dfprintk(MOUNT, "NFS:   invalid "
1447 							"lookupcache argument\n");
1448 					return 0;
1449 			};
1450 			break;
1451 		case Opt_fscache_uniq:
1452 			string = match_strdup(args);
1453 			if (string == NULL)
1454 				goto out_nomem;
1455 			kfree(mnt->fscache_uniq);
1456 			mnt->fscache_uniq = string;
1457 			mnt->options |= NFS_OPTION_FSCACHE;
1458 			break;
1459 		case Opt_local_lock:
1460 			string = match_strdup(args);
1461 			if (string == NULL)
1462 				goto out_nomem;
1463 			token = match_token(string, nfs_local_lock_tokens,
1464 					args);
1465 			kfree(string);
1466 			switch (token) {
1467 			case Opt_local_lock_all:
1468 				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1469 					       NFS_MOUNT_LOCAL_FCNTL);
1470 				break;
1471 			case Opt_local_lock_flock:
1472 				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1473 				break;
1474 			case Opt_local_lock_posix:
1475 				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1476 				break;
1477 			case Opt_local_lock_none:
1478 				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1479 						NFS_MOUNT_LOCAL_FCNTL);
1480 				break;
1481 			default:
1482 				dfprintk(MOUNT, "NFS:	invalid	"
1483 						"local_lock argument\n");
1484 				return 0;
1485 			};
1486 			break;
1487 
1488 		/*
1489 		 * Special options
1490 		 */
1491 		case Opt_sloppy:
1492 			sloppy = 1;
1493 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1494 			break;
1495 		case Opt_userspace:
1496 		case Opt_deprecated:
1497 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1498 					"'%s'\n", p);
1499 			break;
1500 
1501 		default:
1502 			invalid_option = 1;
1503 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1504 					"'%s'\n", p);
1505 		}
1506 	}
1507 
1508 	if (!sloppy && invalid_option)
1509 		return 0;
1510 
1511 	/*
1512 	 * verify that any proto=/mountproto= options match the address
1513 	 * familiies in the addr=/mountaddr= options.
1514 	 */
1515 	if (protofamily != AF_UNSPEC &&
1516 	    protofamily != mnt->nfs_server.address.ss_family)
1517 		goto out_proto_mismatch;
1518 
1519 	if (mountfamily != AF_UNSPEC) {
1520 		if (mnt->mount_server.addrlen) {
1521 			if (mountfamily != mnt->mount_server.address.ss_family)
1522 				goto out_mountproto_mismatch;
1523 		} else {
1524 			if (mountfamily != mnt->nfs_server.address.ss_family)
1525 				goto out_mountproto_mismatch;
1526 		}
1527 	}
1528 
1529 	return 1;
1530 
1531 out_mountproto_mismatch:
1532 	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1533 			 "option\n");
1534 	return 0;
1535 out_proto_mismatch:
1536 	printk(KERN_INFO "NFS: server address does not match proto= option\n");
1537 	return 0;
1538 out_invalid_address:
1539 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1540 	return 0;
1541 out_invalid_value:
1542 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1543 	return 0;
1544 out_nomem:
1545 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1546 	return 0;
1547 out_security_failure:
1548 	free_secdata(secdata);
1549 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1550 	return 0;
1551 }
1552 
1553 /*
1554  * Match the requested auth flavors with the list returned by
1555  * the server.  Returns zero and sets the mount's authentication
1556  * flavor on success; returns -EACCES if server does not support
1557  * the requested flavor.
1558  */
1559 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1560 			     struct nfs_mount_request *request)
1561 {
1562 	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1563 
1564 	/*
1565 	 * Certain releases of Linux's mountd return an empty
1566 	 * flavor list.  To prevent behavioral regression with
1567 	 * these servers (ie. rejecting mounts that used to
1568 	 * succeed), revert to pre-2.6.32 behavior (no checking)
1569 	 * if the returned flavor list is empty.
1570 	 */
1571 	if (server_authlist_len == 0)
1572 		return 0;
1573 
1574 	/*
1575 	 * We avoid sophisticated negotiating here, as there are
1576 	 * plenty of cases where we can get it wrong, providing
1577 	 * either too little or too much security.
1578 	 *
1579 	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
1580 	 * flavor listed first.  However, some servers list
1581 	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1582 	 * preferred default, in args->auth_flavors[0] if user
1583 	 * didn't specify sec= mount option.
1584 	 */
1585 	for (i = 0; i < args->auth_flavor_len; i++)
1586 		for (j = 0; j < server_authlist_len; j++)
1587 			if (args->auth_flavors[i] == request->auth_flavs[j]) {
1588 				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1589 					request->auth_flavs[j]);
1590 				args->auth_flavors[0] = request->auth_flavs[j];
1591 				return 0;
1592 			}
1593 
1594 	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1595 	nfs_umount(request);
1596 	return -EACCES;
1597 }
1598 
1599 /*
1600  * Use the remote server's MOUNT service to request the NFS file handle
1601  * corresponding to the provided path.
1602  */
1603 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1604 			 struct nfs_fh *root_fh)
1605 {
1606 	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1607 	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1608 	struct nfs_mount_request request = {
1609 		.sap		= (struct sockaddr *)
1610 						&args->mount_server.address,
1611 		.dirpath	= args->nfs_server.export_path,
1612 		.protocol	= args->mount_server.protocol,
1613 		.fh		= root_fh,
1614 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1615 		.auth_flav_len	= &server_authlist_len,
1616 		.auth_flavs	= server_authlist,
1617 	};
1618 	int status;
1619 
1620 	if (args->mount_server.version == 0) {
1621 		switch (args->version) {
1622 			default:
1623 				args->mount_server.version = NFS_MNT3_VERSION;
1624 				break;
1625 			case 2:
1626 				args->mount_server.version = NFS_MNT_VERSION;
1627 		}
1628 	}
1629 	request.version = args->mount_server.version;
1630 
1631 	if (args->mount_server.hostname)
1632 		request.hostname = args->mount_server.hostname;
1633 	else
1634 		request.hostname = args->nfs_server.hostname;
1635 
1636 	/*
1637 	 * Construct the mount server's address.
1638 	 */
1639 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1640 		memcpy(request.sap, &args->nfs_server.address,
1641 		       args->nfs_server.addrlen);
1642 		args->mount_server.addrlen = args->nfs_server.addrlen;
1643 	}
1644 	request.salen = args->mount_server.addrlen;
1645 	nfs_set_port(request.sap, &args->mount_server.port, 0);
1646 
1647 	/*
1648 	 * Now ask the mount server to map our export path
1649 	 * to a file handle.
1650 	 */
1651 	status = nfs_mount(&request);
1652 	if (status != 0) {
1653 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1654 				request.hostname, status);
1655 		return status;
1656 	}
1657 
1658 	/*
1659 	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
1660 	 */
1661 	if (args->mount_server.version != NFS_MNT3_VERSION)
1662 		return 0;
1663 	return nfs_walk_authlist(args, &request);
1664 }
1665 
1666 static int nfs_parse_simple_hostname(const char *dev_name,
1667 				     char **hostname, size_t maxnamlen,
1668 				     char **export_path, size_t maxpathlen)
1669 {
1670 	size_t len;
1671 	char *colon, *comma;
1672 
1673 	colon = strchr(dev_name, ':');
1674 	if (colon == NULL)
1675 		goto out_bad_devname;
1676 
1677 	len = colon - dev_name;
1678 	if (len > maxnamlen)
1679 		goto out_hostname;
1680 
1681 	/* N.B. caller will free nfs_server.hostname in all cases */
1682 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1683 	if (!*hostname)
1684 		goto out_nomem;
1685 
1686 	/* kill possible hostname list: not supported */
1687 	comma = strchr(*hostname, ',');
1688 	if (comma != NULL) {
1689 		if (comma == *hostname)
1690 			goto out_bad_devname;
1691 		*comma = '\0';
1692 	}
1693 
1694 	colon++;
1695 	len = strlen(colon);
1696 	if (len > maxpathlen)
1697 		goto out_path;
1698 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1699 	if (!*export_path)
1700 		goto out_nomem;
1701 
1702 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1703 	return 0;
1704 
1705 out_bad_devname:
1706 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1707 	return -EINVAL;
1708 
1709 out_nomem:
1710 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1711 	return -ENOMEM;
1712 
1713 out_hostname:
1714 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1715 	return -ENAMETOOLONG;
1716 
1717 out_path:
1718 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1719 	return -ENAMETOOLONG;
1720 }
1721 
1722 /*
1723  * Hostname has square brackets around it because it contains one or
1724  * more colons.  We look for the first closing square bracket, and a
1725  * colon must follow it.
1726  */
1727 static int nfs_parse_protected_hostname(const char *dev_name,
1728 					char **hostname, size_t maxnamlen,
1729 					char **export_path, size_t maxpathlen)
1730 {
1731 	size_t len;
1732 	char *start, *end;
1733 
1734 	start = (char *)(dev_name + 1);
1735 
1736 	end = strchr(start, ']');
1737 	if (end == NULL)
1738 		goto out_bad_devname;
1739 	if (*(end + 1) != ':')
1740 		goto out_bad_devname;
1741 
1742 	len = end - start;
1743 	if (len > maxnamlen)
1744 		goto out_hostname;
1745 
1746 	/* N.B. caller will free nfs_server.hostname in all cases */
1747 	*hostname = kstrndup(start, len, GFP_KERNEL);
1748 	if (*hostname == NULL)
1749 		goto out_nomem;
1750 
1751 	end += 2;
1752 	len = strlen(end);
1753 	if (len > maxpathlen)
1754 		goto out_path;
1755 	*export_path = kstrndup(end, len, GFP_KERNEL);
1756 	if (!*export_path)
1757 		goto out_nomem;
1758 
1759 	return 0;
1760 
1761 out_bad_devname:
1762 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1763 	return -EINVAL;
1764 
1765 out_nomem:
1766 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1767 	return -ENOMEM;
1768 
1769 out_hostname:
1770 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1771 	return -ENAMETOOLONG;
1772 
1773 out_path:
1774 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1775 	return -ENAMETOOLONG;
1776 }
1777 
1778 /*
1779  * Split "dev_name" into "hostname:export_path".
1780  *
1781  * The leftmost colon demarks the split between the server's hostname
1782  * and the export path.  If the hostname starts with a left square
1783  * bracket, then it may contain colons.
1784  *
1785  * Note: caller frees hostname and export path, even on error.
1786  */
1787 static int nfs_parse_devname(const char *dev_name,
1788 			     char **hostname, size_t maxnamlen,
1789 			     char **export_path, size_t maxpathlen)
1790 {
1791 	if (*dev_name == '[')
1792 		return nfs_parse_protected_hostname(dev_name,
1793 						    hostname, maxnamlen,
1794 						    export_path, maxpathlen);
1795 
1796 	return nfs_parse_simple_hostname(dev_name,
1797 					 hostname, maxnamlen,
1798 					 export_path, maxpathlen);
1799 }
1800 
1801 /*
1802  * Validate the NFS2/NFS3 mount data
1803  * - fills in the mount root filehandle
1804  *
1805  * For option strings, user space handles the following behaviors:
1806  *
1807  * + DNS: mapping server host name to IP address ("addr=" option)
1808  *
1809  * + failure mode: how to behave if a mount request can't be handled
1810  *   immediately ("fg/bg" option)
1811  *
1812  * + retry: how often to retry a mount request ("retry=" option)
1813  *
1814  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1815  *   mountproto=tcp after mountproto=udp, and so on
1816  */
1817 static int nfs_validate_mount_data(void *options,
1818 				   struct nfs_parsed_mount_data *args,
1819 				   struct nfs_fh *mntfh,
1820 				   const char *dev_name)
1821 {
1822 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1823 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1824 
1825 	if (data == NULL)
1826 		goto out_no_data;
1827 
1828 	switch (data->version) {
1829 	case 1:
1830 		data->namlen = 0;
1831 	case 2:
1832 		data->bsize = 0;
1833 	case 3:
1834 		if (data->flags & NFS_MOUNT_VER3)
1835 			goto out_no_v3;
1836 		data->root.size = NFS2_FHSIZE;
1837 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1838 	case 4:
1839 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1840 			goto out_no_sec;
1841 	case 5:
1842 		memset(data->context, 0, sizeof(data->context));
1843 	case 6:
1844 		if (data->flags & NFS_MOUNT_VER3) {
1845 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1846 				goto out_invalid_fh;
1847 			mntfh->size = data->root.size;
1848 			args->version = 3;
1849 		} else {
1850 			mntfh->size = NFS2_FHSIZE;
1851 			args->version = 2;
1852 		}
1853 
1854 
1855 		memcpy(mntfh->data, data->root.data, mntfh->size);
1856 		if (mntfh->size < sizeof(mntfh->data))
1857 			memset(mntfh->data + mntfh->size, 0,
1858 			       sizeof(mntfh->data) - mntfh->size);
1859 
1860 		/*
1861 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1862 		 * can deal with.
1863 		 */
1864 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1865 		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
1866 		args->rsize		= data->rsize;
1867 		args->wsize		= data->wsize;
1868 		args->timeo		= data->timeo;
1869 		args->retrans		= data->retrans;
1870 		args->acregmin		= data->acregmin;
1871 		args->acregmax		= data->acregmax;
1872 		args->acdirmin		= data->acdirmin;
1873 		args->acdirmax		= data->acdirmax;
1874 
1875 		memcpy(sap, &data->addr, sizeof(data->addr));
1876 		args->nfs_server.addrlen = sizeof(data->addr);
1877 		if (!nfs_verify_server_address(sap))
1878 			goto out_no_address;
1879 
1880 		if (!(data->flags & NFS_MOUNT_TCP))
1881 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1882 		/* N.B. caller will free nfs_server.hostname in all cases */
1883 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1884 		args->namlen		= data->namlen;
1885 		args->bsize		= data->bsize;
1886 
1887 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1888 			args->auth_flavors[0] = data->pseudoflavor;
1889 		if (!args->nfs_server.hostname)
1890 			goto out_nomem;
1891 
1892 		if (!(data->flags & NFS_MOUNT_NONLM))
1893 			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1894 					 NFS_MOUNT_LOCAL_FCNTL);
1895 		else
1896 			args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1897 					NFS_MOUNT_LOCAL_FCNTL);
1898 		/*
1899 		 * The legacy version 6 binary mount data from userspace has a
1900 		 * field used only to transport selinux information into the
1901 		 * the kernel.  To continue to support that functionality we
1902 		 * have a touch of selinux knowledge here in the NFS code. The
1903 		 * userspace code converted context=blah to just blah so we are
1904 		 * converting back to the full string selinux understands.
1905 		 */
1906 		if (data->context[0]){
1907 #ifdef CONFIG_SECURITY_SELINUX
1908 			int rc;
1909 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1910 			if (!opts_str)
1911 				return -ENOMEM;
1912 			strcpy(opts_str, "context=");
1913 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1914 			strcat(opts_str, &data->context[0]);
1915 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1916 			kfree(opts_str);
1917 			if (rc)
1918 				return rc;
1919 #else
1920 			return -EINVAL;
1921 #endif
1922 		}
1923 
1924 		break;
1925 	default: {
1926 		int status;
1927 
1928 		if (nfs_parse_mount_options((char *)options, args) == 0)
1929 			return -EINVAL;
1930 
1931 		if (!nfs_verify_server_address(sap))
1932 			goto out_no_address;
1933 
1934 		if (args->version == 4)
1935 #ifdef CONFIG_NFS_V4
1936 			return nfs4_validate_text_mount_data(options,
1937 							     args, dev_name);
1938 #else
1939 			goto out_v4_not_compiled;
1940 #endif
1941 
1942 		nfs_set_port(sap, &args->nfs_server.port, 0);
1943 
1944 		nfs_set_mount_transport_protocol(args);
1945 
1946 		status = nfs_parse_devname(dev_name,
1947 					   &args->nfs_server.hostname,
1948 					   PAGE_SIZE,
1949 					   &args->nfs_server.export_path,
1950 					   NFS_MAXPATHLEN);
1951 		if (!status)
1952 			status = nfs_try_mount(args, mntfh);
1953 
1954 		kfree(args->nfs_server.export_path);
1955 		args->nfs_server.export_path = NULL;
1956 
1957 		if (status)
1958 			return status;
1959 
1960 		break;
1961 		}
1962 	}
1963 
1964 #ifndef CONFIG_NFS_V3
1965 	if (args->version == 3)
1966 		goto out_v3_not_compiled;
1967 #endif /* !CONFIG_NFS_V3 */
1968 
1969 	return 0;
1970 
1971 out_no_data:
1972 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1973 	return -EINVAL;
1974 
1975 out_no_v3:
1976 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1977 		 data->version);
1978 	return -EINVAL;
1979 
1980 out_no_sec:
1981 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1982 	return -EINVAL;
1983 
1984 #ifndef CONFIG_NFS_V3
1985 out_v3_not_compiled:
1986 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1987 	return -EPROTONOSUPPORT;
1988 #endif /* !CONFIG_NFS_V3 */
1989 
1990 #ifndef CONFIG_NFS_V4
1991 out_v4_not_compiled:
1992 	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1993 	return -EPROTONOSUPPORT;
1994 #endif /* !CONFIG_NFS_V4 */
1995 
1996 out_nomem:
1997 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1998 	return -ENOMEM;
1999 
2000 out_no_address:
2001 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2002 	return -EINVAL;
2003 
2004 out_invalid_fh:
2005 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2006 	return -EINVAL;
2007 }
2008 
2009 static int
2010 nfs_compare_remount_data(struct nfs_server *nfss,
2011 			 struct nfs_parsed_mount_data *data)
2012 {
2013 	if (data->flags != nfss->flags ||
2014 	    data->rsize != nfss->rsize ||
2015 	    data->wsize != nfss->wsize ||
2016 	    data->retrans != nfss->client->cl_timeout->to_retries ||
2017 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2018 	    data->acregmin != nfss->acregmin / HZ ||
2019 	    data->acregmax != nfss->acregmax / HZ ||
2020 	    data->acdirmin != nfss->acdirmin / HZ ||
2021 	    data->acdirmax != nfss->acdirmax / HZ ||
2022 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2023 	    data->nfs_server.port != nfss->port ||
2024 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2025 	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2026 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
2027 		return -EINVAL;
2028 
2029 	return 0;
2030 }
2031 
2032 static int
2033 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2034 {
2035 	int error;
2036 	struct nfs_server *nfss = sb->s_fs_info;
2037 	struct nfs_parsed_mount_data *data;
2038 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2039 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2040 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2041 
2042 	/*
2043 	 * Userspace mount programs that send binary options generally send
2044 	 * them populated with default values. We have no way to know which
2045 	 * ones were explicitly specified. Fall back to legacy behavior and
2046 	 * just return success.
2047 	 */
2048 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2049 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
2050 					   options->version <= 6))))
2051 		return 0;
2052 
2053 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2054 	if (data == NULL)
2055 		return -ENOMEM;
2056 
2057 	/* fill out struct with values from existing mount */
2058 	data->flags = nfss->flags;
2059 	data->rsize = nfss->rsize;
2060 	data->wsize = nfss->wsize;
2061 	data->retrans = nfss->client->cl_timeout->to_retries;
2062 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2063 	data->acregmin = nfss->acregmin / HZ;
2064 	data->acregmax = nfss->acregmax / HZ;
2065 	data->acdirmin = nfss->acdirmin / HZ;
2066 	data->acdirmax = nfss->acdirmax / HZ;
2067 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2068 	data->nfs_server.port = nfss->port;
2069 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2070 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2071 		data->nfs_server.addrlen);
2072 
2073 	/* overwrite those values with any that were specified */
2074 	error = nfs_parse_mount_options((char *)options, data);
2075 	if (error < 0)
2076 		goto out;
2077 
2078 	/* compare new mount options with old ones */
2079 	error = nfs_compare_remount_data(nfss, data);
2080 out:
2081 	kfree(data);
2082 	return error;
2083 }
2084 
2085 /*
2086  * Initialise the common bits of the superblock
2087  */
2088 static inline void nfs_initialise_sb(struct super_block *sb)
2089 {
2090 	struct nfs_server *server = NFS_SB(sb);
2091 
2092 	sb->s_magic = NFS_SUPER_MAGIC;
2093 
2094 	/* We probably want something more informative here */
2095 	snprintf(sb->s_id, sizeof(sb->s_id),
2096 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2097 
2098 	if (sb->s_blocksize == 0)
2099 		sb->s_blocksize = nfs_block_bits(server->wsize,
2100 						 &sb->s_blocksize_bits);
2101 
2102 	if (server->flags & NFS_MOUNT_NOAC)
2103 		sb->s_flags |= MS_SYNCHRONOUS;
2104 
2105 	sb->s_bdi = &server->backing_dev_info;
2106 
2107 	nfs_super_set_maxbytes(sb, server->maxfilesize);
2108 }
2109 
2110 /*
2111  * Finish setting up an NFS2/3 superblock
2112  */
2113 static void nfs_fill_super(struct super_block *sb,
2114 			   struct nfs_parsed_mount_data *data)
2115 {
2116 	struct nfs_server *server = NFS_SB(sb);
2117 
2118 	sb->s_blocksize_bits = 0;
2119 	sb->s_blocksize = 0;
2120 	if (data->bsize)
2121 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2122 
2123 	if (server->nfs_client->rpc_ops->version == 3) {
2124 		/* The VFS shouldn't apply the umask to mode bits. We will do
2125 		 * so ourselves when necessary.
2126 		 */
2127 		sb->s_flags |= MS_POSIXACL;
2128 		sb->s_time_gran = 1;
2129 	}
2130 
2131 	sb->s_op = &nfs_sops;
2132  	nfs_initialise_sb(sb);
2133 }
2134 
2135 /*
2136  * Finish setting up a cloned NFS2/3 superblock
2137  */
2138 static void nfs_clone_super(struct super_block *sb,
2139 			    const struct super_block *old_sb)
2140 {
2141 	struct nfs_server *server = NFS_SB(sb);
2142 
2143 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2144 	sb->s_blocksize = old_sb->s_blocksize;
2145 	sb->s_maxbytes = old_sb->s_maxbytes;
2146 
2147 	if (server->nfs_client->rpc_ops->version == 3) {
2148 		/* The VFS shouldn't apply the umask to mode bits. We will do
2149 		 * so ourselves when necessary.
2150 		 */
2151 		sb->s_flags |= MS_POSIXACL;
2152 		sb->s_time_gran = 1;
2153 	}
2154 
2155 	sb->s_op = old_sb->s_op;
2156  	nfs_initialise_sb(sb);
2157 }
2158 
2159 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2160 {
2161 	const struct nfs_server *a = s->s_fs_info;
2162 	const struct rpc_clnt *clnt_a = a->client;
2163 	const struct rpc_clnt *clnt_b = b->client;
2164 
2165 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2166 		goto Ebusy;
2167 	if (a->nfs_client != b->nfs_client)
2168 		goto Ebusy;
2169 	if (a->flags != b->flags)
2170 		goto Ebusy;
2171 	if (a->wsize != b->wsize)
2172 		goto Ebusy;
2173 	if (a->rsize != b->rsize)
2174 		goto Ebusy;
2175 	if (a->acregmin != b->acregmin)
2176 		goto Ebusy;
2177 	if (a->acregmax != b->acregmax)
2178 		goto Ebusy;
2179 	if (a->acdirmin != b->acdirmin)
2180 		goto Ebusy;
2181 	if (a->acdirmax != b->acdirmax)
2182 		goto Ebusy;
2183 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2184 		goto Ebusy;
2185 	return 1;
2186 Ebusy:
2187 	return 0;
2188 }
2189 
2190 struct nfs_sb_mountdata {
2191 	struct nfs_server *server;
2192 	int mntflags;
2193 };
2194 
2195 static int nfs_set_super(struct super_block *s, void *data)
2196 {
2197 	struct nfs_sb_mountdata *sb_mntdata = data;
2198 	struct nfs_server *server = sb_mntdata->server;
2199 	int ret;
2200 
2201 	s->s_flags = sb_mntdata->mntflags;
2202 	s->s_fs_info = server;
2203 	ret = set_anon_super(s, server);
2204 	if (ret == 0)
2205 		server->s_dev = s->s_dev;
2206 	return ret;
2207 }
2208 
2209 static int nfs_compare_super_address(struct nfs_server *server1,
2210 				     struct nfs_server *server2)
2211 {
2212 	struct sockaddr *sap1, *sap2;
2213 
2214 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2215 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2216 
2217 	if (sap1->sa_family != sap2->sa_family)
2218 		return 0;
2219 
2220 	switch (sap1->sa_family) {
2221 	case AF_INET: {
2222 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2223 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2224 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2225 			return 0;
2226 		if (sin1->sin_port != sin2->sin_port)
2227 			return 0;
2228 		break;
2229 	}
2230 	case AF_INET6: {
2231 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2232 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2233 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2234 			return 0;
2235 		if (sin1->sin6_port != sin2->sin6_port)
2236 			return 0;
2237 		break;
2238 	}
2239 	default:
2240 		return 0;
2241 	}
2242 
2243 	return 1;
2244 }
2245 
2246 static int nfs_compare_super(struct super_block *sb, void *data)
2247 {
2248 	struct nfs_sb_mountdata *sb_mntdata = data;
2249 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2250 	int mntflags = sb_mntdata->mntflags;
2251 
2252 	if (!nfs_compare_super_address(old, server))
2253 		return 0;
2254 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2255 	if (old->flags & NFS_MOUNT_UNSHARED)
2256 		return 0;
2257 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2258 		return 0;
2259 	return nfs_compare_mount_options(sb, server, mntflags);
2260 }
2261 
2262 static int nfs_bdi_register(struct nfs_server *server)
2263 {
2264 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2265 }
2266 
2267 static int nfs_get_sb(struct file_system_type *fs_type,
2268 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2269 {
2270 	struct nfs_server *server = NULL;
2271 	struct super_block *s;
2272 	struct nfs_parsed_mount_data *data;
2273 	struct nfs_fh *mntfh;
2274 	struct dentry *mntroot;
2275 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2276 	struct nfs_sb_mountdata sb_mntdata = {
2277 		.mntflags = flags,
2278 	};
2279 	int error = -ENOMEM;
2280 
2281 	data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
2282 	mntfh = nfs_alloc_fhandle();
2283 	if (data == NULL || mntfh == NULL)
2284 		goto out_free_fh;
2285 
2286 	security_init_mnt_opts(&data->lsm_opts);
2287 
2288 	/* Validate the mount data */
2289 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2290 	if (error < 0)
2291 		goto out;
2292 
2293 #ifdef CONFIG_NFS_V4
2294 	if (data->version == 4) {
2295 		error = nfs4_try_mount(flags, dev_name, data, mnt);
2296 		kfree(data->client_address);
2297 		kfree(data->nfs_server.export_path);
2298 		goto out;
2299 	}
2300 #endif	/* CONFIG_NFS_V4 */
2301 
2302 	/* Get a volume representation */
2303 	server = nfs_create_server(data, mntfh);
2304 	if (IS_ERR(server)) {
2305 		error = PTR_ERR(server);
2306 		goto out;
2307 	}
2308 	sb_mntdata.server = server;
2309 
2310 	if (server->flags & NFS_MOUNT_UNSHARED)
2311 		compare_super = NULL;
2312 
2313 	/* Get a superblock - note that we may end up sharing one that already exists */
2314 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2315 	if (IS_ERR(s)) {
2316 		error = PTR_ERR(s);
2317 		goto out_err_nosb;
2318 	}
2319 
2320 	if (s->s_fs_info != server) {
2321 		nfs_free_server(server);
2322 		server = NULL;
2323 	} else {
2324 		error = nfs_bdi_register(server);
2325 		if (error)
2326 			goto error_splat_bdi;
2327 	}
2328 
2329 	if (!s->s_root) {
2330 		/* initial superblock/root creation */
2331 		nfs_fill_super(s, data);
2332 		nfs_fscache_get_super_cookie(
2333 			s, data ? data->fscache_uniq : NULL, NULL);
2334 	}
2335 
2336 	mntroot = nfs_get_root(s, mntfh);
2337 	if (IS_ERR(mntroot)) {
2338 		error = PTR_ERR(mntroot);
2339 		goto error_splat_super;
2340 	}
2341 
2342 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2343 	if (error)
2344 		goto error_splat_root;
2345 
2346 	s->s_flags |= MS_ACTIVE;
2347 	mnt->mnt_sb = s;
2348 	mnt->mnt_root = mntroot;
2349 	error = 0;
2350 
2351 out:
2352 	kfree(data->nfs_server.hostname);
2353 	kfree(data->mount_server.hostname);
2354 	kfree(data->fscache_uniq);
2355 	security_free_mnt_opts(&data->lsm_opts);
2356 out_free_fh:
2357 	nfs_free_fhandle(mntfh);
2358 	kfree(data);
2359 	return error;
2360 
2361 out_err_nosb:
2362 	nfs_free_server(server);
2363 	goto out;
2364 
2365 error_splat_root:
2366 	dput(mntroot);
2367 error_splat_super:
2368 	if (server && !s->s_root)
2369 		bdi_unregister(&server->backing_dev_info);
2370 error_splat_bdi:
2371 	deactivate_locked_super(s);
2372 	goto out;
2373 }
2374 
2375 /*
2376  * Ensure that we unregister the bdi before kill_anon_super
2377  * releases the device name
2378  */
2379 static void nfs_put_super(struct super_block *s)
2380 {
2381 	struct nfs_server *server = NFS_SB(s);
2382 
2383 	bdi_unregister(&server->backing_dev_info);
2384 }
2385 
2386 /*
2387  * Destroy an NFS2/3 superblock
2388  */
2389 static void nfs_kill_super(struct super_block *s)
2390 {
2391 	struct nfs_server *server = NFS_SB(s);
2392 
2393 	kill_anon_super(s);
2394 	nfs_fscache_release_super_cookie(s);
2395 	nfs_free_server(server);
2396 }
2397 
2398 /*
2399  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2400  */
2401 static struct dentry *
2402 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2403 		const char *dev_name, void *raw_data)
2404 {
2405 	struct nfs_clone_mount *data = raw_data;
2406 	struct super_block *s;
2407 	struct nfs_server *server;
2408 	struct dentry *mntroot;
2409 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2410 	struct nfs_sb_mountdata sb_mntdata = {
2411 		.mntflags = flags,
2412 	};
2413 	int error;
2414 
2415 	dprintk("--> nfs_xdev_mount()\n");
2416 
2417 	/* create a new volume representation */
2418 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2419 	if (IS_ERR(server)) {
2420 		error = PTR_ERR(server);
2421 		goto out_err_noserver;
2422 	}
2423 	sb_mntdata.server = server;
2424 
2425 	if (server->flags & NFS_MOUNT_UNSHARED)
2426 		compare_super = NULL;
2427 
2428 	/* Get a superblock - note that we may end up sharing one that already exists */
2429 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2430 	if (IS_ERR(s)) {
2431 		error = PTR_ERR(s);
2432 		goto out_err_nosb;
2433 	}
2434 
2435 	if (s->s_fs_info != server) {
2436 		nfs_free_server(server);
2437 		server = NULL;
2438 	} else {
2439 		error = nfs_bdi_register(server);
2440 		if (error)
2441 			goto error_splat_bdi;
2442 	}
2443 
2444 	if (!s->s_root) {
2445 		/* initial superblock/root creation */
2446 		nfs_clone_super(s, data->sb);
2447 		nfs_fscache_get_super_cookie(s, NULL, data);
2448 	}
2449 
2450 	mntroot = nfs_get_root(s, data->fh);
2451 	if (IS_ERR(mntroot)) {
2452 		error = PTR_ERR(mntroot);
2453 		goto error_splat_super;
2454 	}
2455 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2456 		dput(mntroot);
2457 		error = -ESTALE;
2458 		goto error_splat_super;
2459 	}
2460 
2461 	s->s_flags |= MS_ACTIVE;
2462 
2463 	/* clone any lsm security options from the parent to the new sb */
2464 	security_sb_clone_mnt_opts(data->sb, s);
2465 
2466 	dprintk("<-- nfs_xdev_mount() = 0\n");
2467 	return mntroot;
2468 
2469 out_err_nosb:
2470 	nfs_free_server(server);
2471 out_err_noserver:
2472 	dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2473 	return ERR_PTR(error);
2474 
2475 error_splat_super:
2476 	if (server && !s->s_root)
2477 		bdi_unregister(&server->backing_dev_info);
2478 error_splat_bdi:
2479 	deactivate_locked_super(s);
2480 	dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2481 	return ERR_PTR(error);
2482 }
2483 
2484 #ifdef CONFIG_NFS_V4
2485 
2486 /*
2487  * Finish setting up a cloned NFS4 superblock
2488  */
2489 static void nfs4_clone_super(struct super_block *sb,
2490 			    const struct super_block *old_sb)
2491 {
2492 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2493 	sb->s_blocksize = old_sb->s_blocksize;
2494 	sb->s_maxbytes = old_sb->s_maxbytes;
2495 	sb->s_time_gran = 1;
2496 	sb->s_op = old_sb->s_op;
2497  	nfs_initialise_sb(sb);
2498 }
2499 
2500 /*
2501  * Set up an NFS4 superblock
2502  */
2503 static void nfs4_fill_super(struct super_block *sb)
2504 {
2505 	sb->s_time_gran = 1;
2506 	sb->s_op = &nfs4_sops;
2507 	nfs_initialise_sb(sb);
2508 }
2509 
2510 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2511 {
2512 	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2513 			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2514 }
2515 
2516 static int nfs4_validate_text_mount_data(void *options,
2517 					 struct nfs_parsed_mount_data *args,
2518 					 const char *dev_name)
2519 {
2520 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2521 
2522 	nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2523 
2524 	nfs_validate_transport_protocol(args);
2525 
2526 	nfs4_validate_mount_flags(args);
2527 
2528 	if (args->version != 4) {
2529 		dfprintk(MOUNT,
2530 			 "NFS4: Illegal mount version\n");
2531 		return -EINVAL;
2532 	}
2533 
2534 	if (args->auth_flavor_len > 1) {
2535 		dfprintk(MOUNT,
2536 			 "NFS4: Too many RPC auth flavours specified\n");
2537 		return -EINVAL;
2538 	}
2539 
2540 	if (args->client_address == NULL) {
2541 		dfprintk(MOUNT,
2542 			 "NFS4: mount program didn't pass callback address\n");
2543 		return -EINVAL;
2544 	}
2545 
2546 	return nfs_parse_devname(dev_name,
2547 				   &args->nfs_server.hostname,
2548 				   NFS4_MAXNAMLEN,
2549 				   &args->nfs_server.export_path,
2550 				   NFS4_MAXPATHLEN);
2551 }
2552 
2553 /*
2554  * Validate NFSv4 mount options
2555  */
2556 static int nfs4_validate_mount_data(void *options,
2557 				    struct nfs_parsed_mount_data *args,
2558 				    const char *dev_name)
2559 {
2560 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2561 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2562 	char *c;
2563 
2564 	if (data == NULL)
2565 		goto out_no_data;
2566 
2567 	switch (data->version) {
2568 	case 1:
2569 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2570 			goto out_no_address;
2571 		if (data->host_addrlen == 0)
2572 			goto out_no_address;
2573 		args->nfs_server.addrlen = data->host_addrlen;
2574 		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2575 			return -EFAULT;
2576 		if (!nfs_verify_server_address(sap))
2577 			goto out_no_address;
2578 
2579 		if (data->auth_flavourlen) {
2580 			if (data->auth_flavourlen > 1)
2581 				goto out_inval_auth;
2582 			if (copy_from_user(&args->auth_flavors[0],
2583 					   data->auth_flavours,
2584 					   sizeof(args->auth_flavors[0])))
2585 				return -EFAULT;
2586 		}
2587 
2588 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2589 		if (IS_ERR(c))
2590 			return PTR_ERR(c);
2591 		args->nfs_server.hostname = c;
2592 
2593 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2594 		if (IS_ERR(c))
2595 			return PTR_ERR(c);
2596 		args->nfs_server.export_path = c;
2597 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2598 
2599 		c = strndup_user(data->client_addr.data, 16);
2600 		if (IS_ERR(c))
2601 			return PTR_ERR(c);
2602 		args->client_address = c;
2603 
2604 		/*
2605 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2606 		 * can deal with.
2607 		 */
2608 
2609 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2610 		args->rsize	= data->rsize;
2611 		args->wsize	= data->wsize;
2612 		args->timeo	= data->timeo;
2613 		args->retrans	= data->retrans;
2614 		args->acregmin	= data->acregmin;
2615 		args->acregmax	= data->acregmax;
2616 		args->acdirmin	= data->acdirmin;
2617 		args->acdirmax	= data->acdirmax;
2618 		args->nfs_server.protocol = data->proto;
2619 		nfs_validate_transport_protocol(args);
2620 
2621 		break;
2622 	default:
2623 		if (nfs_parse_mount_options((char *)options, args) == 0)
2624 			return -EINVAL;
2625 
2626 		if (!nfs_verify_server_address(sap))
2627 			return -EINVAL;
2628 
2629 		return nfs4_validate_text_mount_data(options, args, dev_name);
2630 	}
2631 
2632 	return 0;
2633 
2634 out_no_data:
2635 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2636 	return -EINVAL;
2637 
2638 out_inval_auth:
2639 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2640 		 data->auth_flavourlen);
2641 	return -EINVAL;
2642 
2643 out_no_address:
2644 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2645 	return -EINVAL;
2646 }
2647 
2648 /*
2649  * Get the superblock for the NFS4 root partition
2650  */
2651 static struct dentry *
2652 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2653 		  const char *dev_name, void *raw_data)
2654 {
2655 	struct nfs_parsed_mount_data *data = raw_data;
2656 	struct super_block *s;
2657 	struct nfs_server *server;
2658 	struct nfs_fh *mntfh;
2659 	struct dentry *mntroot;
2660 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2661 	struct nfs_sb_mountdata sb_mntdata = {
2662 		.mntflags = flags,
2663 	};
2664 	int error = -ENOMEM;
2665 
2666 	mntfh = nfs_alloc_fhandle();
2667 	if (data == NULL || mntfh == NULL)
2668 		goto out_free_fh;
2669 
2670 	security_init_mnt_opts(&data->lsm_opts);
2671 
2672 	/* Get a volume representation */
2673 	server = nfs4_create_server(data, mntfh);
2674 	if (IS_ERR(server)) {
2675 		error = PTR_ERR(server);
2676 		goto out;
2677 	}
2678 	sb_mntdata.server = server;
2679 
2680 	if (server->flags & NFS4_MOUNT_UNSHARED)
2681 		compare_super = NULL;
2682 
2683 	/* Get a superblock - note that we may end up sharing one that already exists */
2684 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2685 	if (IS_ERR(s)) {
2686 		error = PTR_ERR(s);
2687 		goto out_free;
2688 	}
2689 
2690 	if (s->s_fs_info != server) {
2691 		nfs_free_server(server);
2692 		server = NULL;
2693 	} else {
2694 		error = nfs_bdi_register(server);
2695 		if (error)
2696 			goto error_splat_bdi;
2697 	}
2698 
2699 	if (!s->s_root) {
2700 		/* initial superblock/root creation */
2701 		nfs4_fill_super(s);
2702 		nfs_fscache_get_super_cookie(
2703 			s, data ? data->fscache_uniq : NULL, NULL);
2704 	}
2705 
2706 	mntroot = nfs4_get_root(s, mntfh);
2707 	if (IS_ERR(mntroot)) {
2708 		error = PTR_ERR(mntroot);
2709 		goto error_splat_super;
2710 	}
2711 
2712 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2713 	if (error)
2714 		goto error_splat_root;
2715 
2716 	s->s_flags |= MS_ACTIVE;
2717 
2718 	security_free_mnt_opts(&data->lsm_opts);
2719 	nfs_free_fhandle(mntfh);
2720 	return mntroot;
2721 
2722 out:
2723 	security_free_mnt_opts(&data->lsm_opts);
2724 out_free_fh:
2725 	nfs_free_fhandle(mntfh);
2726 	return ERR_PTR(error);
2727 
2728 out_free:
2729 	nfs_free_server(server);
2730 	goto out;
2731 
2732 error_splat_root:
2733 	dput(mntroot);
2734 error_splat_super:
2735 	if (server && !s->s_root)
2736 		bdi_unregister(&server->backing_dev_info);
2737 error_splat_bdi:
2738 	deactivate_locked_super(s);
2739 	goto out;
2740 }
2741 
2742 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2743 		int flags, void *data, const char *hostname)
2744 {
2745 	struct vfsmount *root_mnt;
2746 	char *root_devname;
2747 	size_t len;
2748 
2749 	len = strlen(hostname) + 3;
2750 	root_devname = kmalloc(len, GFP_KERNEL);
2751 	if (root_devname == NULL)
2752 		return ERR_PTR(-ENOMEM);
2753 	snprintf(root_devname, len, "%s:/", hostname);
2754 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2755 	kfree(root_devname);
2756 	return root_mnt;
2757 }
2758 
2759 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2760 {
2761 	char *page = (char *) __get_free_page(GFP_KERNEL);
2762 	char *devname, *tmp;
2763 
2764 	if (page == NULL)
2765 		return;
2766 	devname = nfs_path(path->mnt->mnt_devname,
2767 			path->mnt->mnt_root, path->dentry,
2768 			page, PAGE_SIZE);
2769 	if (IS_ERR(devname))
2770 		goto out_freepage;
2771 	tmp = kstrdup(devname, GFP_KERNEL);
2772 	if (tmp == NULL)
2773 		goto out_freepage;
2774 	kfree(mnt->mnt_devname);
2775 	mnt->mnt_devname = tmp;
2776 out_freepage:
2777 	free_page((unsigned long)page);
2778 }
2779 
2780 struct nfs_referral_count {
2781 	struct list_head list;
2782 	const struct task_struct *task;
2783 	unsigned int referral_count;
2784 };
2785 
2786 static LIST_HEAD(nfs_referral_count_list);
2787 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2788 
2789 static struct nfs_referral_count *nfs_find_referral_count(void)
2790 {
2791 	struct nfs_referral_count *p;
2792 
2793 	list_for_each_entry(p, &nfs_referral_count_list, list) {
2794 		if (p->task == current)
2795 			return p;
2796 	}
2797 	return NULL;
2798 }
2799 
2800 #define NFS_MAX_NESTED_REFERRALS 2
2801 
2802 static int nfs_referral_loop_protect(void)
2803 {
2804 	struct nfs_referral_count *p, *new;
2805 	int ret = -ENOMEM;
2806 
2807 	new = kmalloc(sizeof(*new), GFP_KERNEL);
2808 	if (!new)
2809 		goto out;
2810 	new->task = current;
2811 	new->referral_count = 1;
2812 
2813 	ret = 0;
2814 	spin_lock(&nfs_referral_count_list_lock);
2815 	p = nfs_find_referral_count();
2816 	if (p != NULL) {
2817 		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2818 			ret = -ELOOP;
2819 		else
2820 			p->referral_count++;
2821 	} else {
2822 		list_add(&new->list, &nfs_referral_count_list);
2823 		new = NULL;
2824 	}
2825 	spin_unlock(&nfs_referral_count_list_lock);
2826 	kfree(new);
2827 out:
2828 	return ret;
2829 }
2830 
2831 static void nfs_referral_loop_unprotect(void)
2832 {
2833 	struct nfs_referral_count *p;
2834 
2835 	spin_lock(&nfs_referral_count_list_lock);
2836 	p = nfs_find_referral_count();
2837 	p->referral_count--;
2838 	if (p->referral_count == 0)
2839 		list_del(&p->list);
2840 	else
2841 		p = NULL;
2842 	spin_unlock(&nfs_referral_count_list_lock);
2843 	kfree(p);
2844 }
2845 
2846 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2847 		const char *export_path, struct vfsmount *mnt_target)
2848 {
2849 	struct nameidata *nd = NULL;
2850 	struct mnt_namespace *ns_private;
2851 	struct super_block *s;
2852 	int ret;
2853 
2854 	nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2855 	if (nd == NULL)
2856 		return -ENOMEM;
2857 
2858 	ns_private = create_mnt_ns(root_mnt);
2859 	ret = PTR_ERR(ns_private);
2860 	if (IS_ERR(ns_private))
2861 		goto out_mntput;
2862 
2863 	ret = nfs_referral_loop_protect();
2864 	if (ret != 0)
2865 		goto out_put_mnt_ns;
2866 
2867 	ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2868 			export_path, LOOKUP_FOLLOW, nd);
2869 
2870 	nfs_referral_loop_unprotect();
2871 	put_mnt_ns(ns_private);
2872 
2873 	if (ret != 0)
2874 		goto out_err;
2875 
2876 	s = nd->path.mnt->mnt_sb;
2877 	atomic_inc(&s->s_active);
2878 	mnt_target->mnt_sb = s;
2879 	mnt_target->mnt_root = dget(nd->path.dentry);
2880 
2881 	/* Correct the device pathname */
2882 	nfs_fix_devname(&nd->path, mnt_target);
2883 
2884 	path_put(&nd->path);
2885 	kfree(nd);
2886 	down_write(&s->s_umount);
2887 	return 0;
2888 out_put_mnt_ns:
2889 	put_mnt_ns(ns_private);
2890 out_mntput:
2891 	mntput(root_mnt);
2892 out_err:
2893 	kfree(nd);
2894 	return ret;
2895 }
2896 
2897 static int nfs4_try_mount(int flags, const char *dev_name,
2898 			 struct nfs_parsed_mount_data *data,
2899 			 struct vfsmount *mnt)
2900 {
2901 	char *export_path;
2902 	struct vfsmount *root_mnt;
2903 	int error;
2904 
2905 	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2906 
2907 	export_path = data->nfs_server.export_path;
2908 	data->nfs_server.export_path = "/";
2909 	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2910 			data->nfs_server.hostname);
2911 	data->nfs_server.export_path = export_path;
2912 
2913 	error = PTR_ERR(root_mnt);
2914 	if (IS_ERR(root_mnt))
2915 		goto out;
2916 
2917 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2918 
2919 out:
2920 	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2921 			error != 0 ? " [error]" : "");
2922 	return error;
2923 }
2924 
2925 /*
2926  * Get the superblock for an NFS4 mountpoint
2927  */
2928 static int nfs4_get_sb(struct file_system_type *fs_type,
2929 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2930 {
2931 	struct nfs_parsed_mount_data *data;
2932 	int error = -ENOMEM;
2933 
2934 	data = nfs_alloc_parsed_mount_data(4);
2935 	if (data == NULL)
2936 		goto out_free_data;
2937 
2938 	/* Validate the mount data */
2939 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2940 	if (error < 0)
2941 		goto out;
2942 
2943 	error = nfs4_try_mount(flags, dev_name, data, mnt);
2944 
2945 out:
2946 	kfree(data->client_address);
2947 	kfree(data->nfs_server.export_path);
2948 	kfree(data->nfs_server.hostname);
2949 	kfree(data->fscache_uniq);
2950 out_free_data:
2951 	kfree(data);
2952 	dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2953 			error != 0 ? " [error]" : "");
2954 	return error;
2955 }
2956 
2957 static void nfs4_kill_super(struct super_block *sb)
2958 {
2959 	struct nfs_server *server = NFS_SB(sb);
2960 
2961 	dprintk("--> %s\n", __func__);
2962 	nfs_super_return_all_delegations(sb);
2963 	kill_anon_super(sb);
2964 	nfs_fscache_release_super_cookie(sb);
2965 	nfs_free_server(server);
2966 	dprintk("<-- %s\n", __func__);
2967 }
2968 
2969 /*
2970  * Clone an NFS4 server record on xdev traversal (FSID-change)
2971  */
2972 static struct dentry *
2973 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2974 		 const char *dev_name, void *raw_data)
2975 {
2976 	struct nfs_clone_mount *data = raw_data;
2977 	struct super_block *s;
2978 	struct nfs_server *server;
2979 	struct dentry *mntroot;
2980 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2981 	struct nfs_sb_mountdata sb_mntdata = {
2982 		.mntflags = flags,
2983 	};
2984 	int error;
2985 
2986 	dprintk("--> nfs4_xdev_mount()\n");
2987 
2988 	/* create a new volume representation */
2989 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2990 	if (IS_ERR(server)) {
2991 		error = PTR_ERR(server);
2992 		goto out_err_noserver;
2993 	}
2994 	sb_mntdata.server = server;
2995 
2996 	if (server->flags & NFS4_MOUNT_UNSHARED)
2997 		compare_super = NULL;
2998 
2999 	/* Get a superblock - note that we may end up sharing one that already exists */
3000 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3001 	if (IS_ERR(s)) {
3002 		error = PTR_ERR(s);
3003 		goto out_err_nosb;
3004 	}
3005 
3006 	if (s->s_fs_info != server) {
3007 		nfs_free_server(server);
3008 		server = NULL;
3009 	} else {
3010 		error = nfs_bdi_register(server);
3011 		if (error)
3012 			goto error_splat_bdi;
3013 	}
3014 
3015 	if (!s->s_root) {
3016 		/* initial superblock/root creation */
3017 		nfs4_clone_super(s, data->sb);
3018 		nfs_fscache_get_super_cookie(s, NULL, data);
3019 	}
3020 
3021 	mntroot = nfs4_get_root(s, data->fh);
3022 	if (IS_ERR(mntroot)) {
3023 		error = PTR_ERR(mntroot);
3024 		goto error_splat_super;
3025 	}
3026 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3027 		dput(mntroot);
3028 		error = -ESTALE;
3029 		goto error_splat_super;
3030 	}
3031 
3032 	s->s_flags |= MS_ACTIVE;
3033 
3034 	security_sb_clone_mnt_opts(data->sb, s);
3035 
3036 	dprintk("<-- nfs4_xdev_mount() = 0\n");
3037 	return mntroot;
3038 
3039 out_err_nosb:
3040 	nfs_free_server(server);
3041 out_err_noserver:
3042 	dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3043 	return ERR_PTR(error);
3044 
3045 error_splat_super:
3046 	if (server && !s->s_root)
3047 		bdi_unregister(&server->backing_dev_info);
3048 error_splat_bdi:
3049 	deactivate_locked_super(s);
3050 	dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3051 	return ERR_PTR(error);
3052 }
3053 
3054 static struct dentry *
3055 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3056 			   const char *dev_name, void *raw_data)
3057 {
3058 	struct nfs_clone_mount *data = raw_data;
3059 	struct super_block *s;
3060 	struct nfs_server *server;
3061 	struct dentry *mntroot;
3062 	struct nfs_fh *mntfh;
3063 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3064 	struct nfs_sb_mountdata sb_mntdata = {
3065 		.mntflags = flags,
3066 	};
3067 	int error = -ENOMEM;
3068 
3069 	dprintk("--> nfs4_referral_get_sb()\n");
3070 
3071 	mntfh = nfs_alloc_fhandle();
3072 	if (mntfh == NULL)
3073 		goto out_err_nofh;
3074 
3075 	/* create a new volume representation */
3076 	server = nfs4_create_referral_server(data, mntfh);
3077 	if (IS_ERR(server)) {
3078 		error = PTR_ERR(server);
3079 		goto out_err_noserver;
3080 	}
3081 	sb_mntdata.server = server;
3082 
3083 	if (server->flags & NFS4_MOUNT_UNSHARED)
3084 		compare_super = NULL;
3085 
3086 	/* Get a superblock - note that we may end up sharing one that already exists */
3087 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3088 	if (IS_ERR(s)) {
3089 		error = PTR_ERR(s);
3090 		goto out_err_nosb;
3091 	}
3092 
3093 	if (s->s_fs_info != server) {
3094 		nfs_free_server(server);
3095 		server = NULL;
3096 	} else {
3097 		error = nfs_bdi_register(server);
3098 		if (error)
3099 			goto error_splat_bdi;
3100 	}
3101 
3102 	if (!s->s_root) {
3103 		/* initial superblock/root creation */
3104 		nfs4_fill_super(s);
3105 		nfs_fscache_get_super_cookie(s, NULL, data);
3106 	}
3107 
3108 	mntroot = nfs4_get_root(s, mntfh);
3109 	if (IS_ERR(mntroot)) {
3110 		error = PTR_ERR(mntroot);
3111 		goto error_splat_super;
3112 	}
3113 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3114 		dput(mntroot);
3115 		error = -ESTALE;
3116 		goto error_splat_super;
3117 	}
3118 
3119 	s->s_flags |= MS_ACTIVE;
3120 
3121 	security_sb_clone_mnt_opts(data->sb, s);
3122 
3123 	nfs_free_fhandle(mntfh);
3124 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
3125 	return mntroot;
3126 
3127 out_err_nosb:
3128 	nfs_free_server(server);
3129 out_err_noserver:
3130 	nfs_free_fhandle(mntfh);
3131 out_err_nofh:
3132 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3133 	return ERR_PTR(error);
3134 
3135 error_splat_super:
3136 	if (server && !s->s_root)
3137 		bdi_unregister(&server->backing_dev_info);
3138 error_splat_bdi:
3139 	deactivate_locked_super(s);
3140 	nfs_free_fhandle(mntfh);
3141 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3142 	return ERR_PTR(error);
3143 }
3144 
3145 /*
3146  * Create an NFS4 server record on referral traversal
3147  */
3148 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3149 		int flags, const char *dev_name, void *raw_data,
3150 		struct vfsmount *mnt)
3151 {
3152 	struct nfs_clone_mount *data = raw_data;
3153 	char *export_path;
3154 	struct vfsmount *root_mnt;
3155 	int error;
3156 
3157 	dprintk("--> nfs4_referral_get_sb()\n");
3158 
3159 	export_path = data->mnt_path;
3160 	data->mnt_path = "/";
3161 
3162 	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3163 			flags, data, data->hostname);
3164 	data->mnt_path = export_path;
3165 
3166 	error = PTR_ERR(root_mnt);
3167 	if (IS_ERR(root_mnt))
3168 		goto out;
3169 
3170 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3171 out:
3172 	dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3173 			error != 0 ? " [error]" : "");
3174 	return error;
3175 }
3176 
3177 #endif /* CONFIG_NFS_V4 */
3178