xref: /openbmc/linux/fs/nfs/super.c (revision b595076a)
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/smp_lock.h>
43 #include <linux/seq_file.h>
44 #include <linux/mount.h>
45 #include <linux/mnt_namespace.h>
46 #include <linux/namei.h>
47 #include <linux/nfs_idmap.h>
48 #include <linux/vfs.h>
49 #include <linux/inet.h>
50 #include <linux/in6.h>
51 #include <linux/slab.h>
52 #include <net/ipv6.h>
53 #include <linux/netdevice.h>
54 #include <linux/nfs_xdr.h>
55 #include <linux/magic.h>
56 #include <linux/parser.h>
57 
58 #include <asm/system.h>
59 #include <asm/uaccess.h>
60 
61 #include "nfs4_fs.h"
62 #include "callback.h"
63 #include "delegation.h"
64 #include "iostat.h"
65 #include "internal.h"
66 #include "fscache.h"
67 
68 #define NFSDBG_FACILITY		NFSDBG_VFS
69 
70 enum {
71 	/* Mount options that take no arguments */
72 	Opt_soft, Opt_hard,
73 	Opt_posix, Opt_noposix,
74 	Opt_cto, Opt_nocto,
75 	Opt_ac, Opt_noac,
76 	Opt_lock, Opt_nolock,
77 	Opt_v2, Opt_v3, Opt_v4,
78 	Opt_udp, Opt_tcp, Opt_rdma,
79 	Opt_acl, Opt_noacl,
80 	Opt_rdirplus, Opt_nordirplus,
81 	Opt_sharecache, Opt_nosharecache,
82 	Opt_resvport, Opt_noresvport,
83 	Opt_fscache, Opt_nofscache,
84 
85 	/* Mount options that take integer arguments */
86 	Opt_port,
87 	Opt_rsize, Opt_wsize, Opt_bsize,
88 	Opt_timeo, Opt_retrans,
89 	Opt_acregmin, Opt_acregmax,
90 	Opt_acdirmin, Opt_acdirmax,
91 	Opt_actimeo,
92 	Opt_namelen,
93 	Opt_mountport,
94 	Opt_mountvers,
95 	Opt_nfsvers,
96 	Opt_minorversion,
97 
98 	/* Mount options that take string arguments */
99 	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
100 	Opt_addr, Opt_mountaddr, Opt_clientaddr,
101 	Opt_lookupcache,
102 	Opt_fscache_uniq,
103 	Opt_local_lock,
104 
105 	/* Special mount options */
106 	Opt_userspace, Opt_deprecated, Opt_sloppy,
107 
108 	Opt_err
109 };
110 
111 static const match_table_t nfs_mount_option_tokens = {
112 	{ Opt_userspace, "bg" },
113 	{ Opt_userspace, "fg" },
114 	{ Opt_userspace, "retry=%s" },
115 
116 	{ Opt_sloppy, "sloppy" },
117 
118 	{ Opt_soft, "soft" },
119 	{ Opt_hard, "hard" },
120 	{ Opt_deprecated, "intr" },
121 	{ Opt_deprecated, "nointr" },
122 	{ Opt_posix, "posix" },
123 	{ Opt_noposix, "noposix" },
124 	{ Opt_cto, "cto" },
125 	{ Opt_nocto, "nocto" },
126 	{ Opt_ac, "ac" },
127 	{ Opt_noac, "noac" },
128 	{ Opt_lock, "lock" },
129 	{ Opt_nolock, "nolock" },
130 	{ Opt_v2, "v2" },
131 	{ Opt_v3, "v3" },
132 	{ Opt_v4, "v4" },
133 	{ Opt_udp, "udp" },
134 	{ Opt_tcp, "tcp" },
135 	{ Opt_rdma, "rdma" },
136 	{ Opt_acl, "acl" },
137 	{ Opt_noacl, "noacl" },
138 	{ Opt_rdirplus, "rdirplus" },
139 	{ Opt_nordirplus, "nordirplus" },
140 	{ Opt_sharecache, "sharecache" },
141 	{ Opt_nosharecache, "nosharecache" },
142 	{ Opt_resvport, "resvport" },
143 	{ Opt_noresvport, "noresvport" },
144 	{ Opt_fscache, "fsc" },
145 	{ Opt_nofscache, "nofsc" },
146 
147 	{ Opt_port, "port=%s" },
148 	{ Opt_rsize, "rsize=%s" },
149 	{ Opt_wsize, "wsize=%s" },
150 	{ Opt_bsize, "bsize=%s" },
151 	{ Opt_timeo, "timeo=%s" },
152 	{ Opt_retrans, "retrans=%s" },
153 	{ Opt_acregmin, "acregmin=%s" },
154 	{ Opt_acregmax, "acregmax=%s" },
155 	{ Opt_acdirmin, "acdirmin=%s" },
156 	{ Opt_acdirmax, "acdirmax=%s" },
157 	{ Opt_actimeo, "actimeo=%s" },
158 	{ Opt_namelen, "namlen=%s" },
159 	{ Opt_mountport, "mountport=%s" },
160 	{ Opt_mountvers, "mountvers=%s" },
161 	{ Opt_nfsvers, "nfsvers=%s" },
162 	{ Opt_nfsvers, "vers=%s" },
163 	{ Opt_minorversion, "minorversion=%s" },
164 
165 	{ Opt_sec, "sec=%s" },
166 	{ Opt_proto, "proto=%s" },
167 	{ Opt_mountproto, "mountproto=%s" },
168 	{ Opt_addr, "addr=%s" },
169 	{ Opt_clientaddr, "clientaddr=%s" },
170 	{ Opt_mounthost, "mounthost=%s" },
171 	{ Opt_mountaddr, "mountaddr=%s" },
172 
173 	{ Opt_lookupcache, "lookupcache=%s" },
174 	{ Opt_fscache_uniq, "fsc=%s" },
175 	{ Opt_local_lock, "local_lock=%s" },
176 
177 	{ Opt_err, NULL }
178 };
179 
180 enum {
181 	Opt_xprt_udp, Opt_xprt_udp6, Opt_xprt_tcp, Opt_xprt_tcp6, Opt_xprt_rdma,
182 
183 	Opt_xprt_err
184 };
185 
186 static const match_table_t nfs_xprt_protocol_tokens = {
187 	{ Opt_xprt_udp, "udp" },
188 	{ Opt_xprt_udp6, "udp6" },
189 	{ Opt_xprt_tcp, "tcp" },
190 	{ Opt_xprt_tcp6, "tcp6" },
191 	{ Opt_xprt_rdma, "rdma" },
192 
193 	{ Opt_xprt_err, NULL }
194 };
195 
196 enum {
197 	Opt_sec_none, Opt_sec_sys,
198 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
199 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
200 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
201 
202 	Opt_sec_err
203 };
204 
205 static const match_table_t nfs_secflavor_tokens = {
206 	{ Opt_sec_none, "none" },
207 	{ Opt_sec_none, "null" },
208 	{ Opt_sec_sys, "sys" },
209 
210 	{ Opt_sec_krb5, "krb5" },
211 	{ Opt_sec_krb5i, "krb5i" },
212 	{ Opt_sec_krb5p, "krb5p" },
213 
214 	{ Opt_sec_lkey, "lkey" },
215 	{ Opt_sec_lkeyi, "lkeyi" },
216 	{ Opt_sec_lkeyp, "lkeyp" },
217 
218 	{ Opt_sec_spkm, "spkm3" },
219 	{ Opt_sec_spkmi, "spkm3i" },
220 	{ Opt_sec_spkmp, "spkm3p" },
221 
222 	{ Opt_sec_err, NULL }
223 };
224 
225 enum {
226 	Opt_lookupcache_all, Opt_lookupcache_positive,
227 	Opt_lookupcache_none,
228 
229 	Opt_lookupcache_err
230 };
231 
232 static match_table_t nfs_lookupcache_tokens = {
233 	{ Opt_lookupcache_all, "all" },
234 	{ Opt_lookupcache_positive, "pos" },
235 	{ Opt_lookupcache_positive, "positive" },
236 	{ Opt_lookupcache_none, "none" },
237 
238 	{ Opt_lookupcache_err, NULL }
239 };
240 
241 enum {
242 	Opt_local_lock_all, Opt_local_lock_flock, Opt_local_lock_posix,
243 	Opt_local_lock_none,
244 
245 	Opt_local_lock_err
246 };
247 
248 static match_table_t nfs_local_lock_tokens = {
249 	{ Opt_local_lock_all, "all" },
250 	{ Opt_local_lock_flock, "flock" },
251 	{ Opt_local_lock_posix, "posix" },
252 	{ Opt_local_lock_none, "none" },
253 
254 	{ Opt_local_lock_err, NULL }
255 };
256 
257 
258 static void nfs_umount_begin(struct super_block *);
259 static int  nfs_statfs(struct dentry *, struct kstatfs *);
260 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
261 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
262 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
263 static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
264 		int flags, const char *dev_name, void *raw_data);
265 static void nfs_put_super(struct super_block *);
266 static void nfs_kill_super(struct super_block *);
267 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
268 
269 static struct file_system_type nfs_fs_type = {
270 	.owner		= THIS_MODULE,
271 	.name		= "nfs",
272 	.get_sb		= nfs_get_sb,
273 	.kill_sb	= nfs_kill_super,
274 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
275 };
276 
277 struct file_system_type nfs_xdev_fs_type = {
278 	.owner		= THIS_MODULE,
279 	.name		= "nfs",
280 	.mount		= nfs_xdev_mount,
281 	.kill_sb	= nfs_kill_super,
282 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
283 };
284 
285 static const struct super_operations nfs_sops = {
286 	.alloc_inode	= nfs_alloc_inode,
287 	.destroy_inode	= nfs_destroy_inode,
288 	.write_inode	= nfs_write_inode,
289 	.put_super	= nfs_put_super,
290 	.statfs		= nfs_statfs,
291 	.evict_inode	= nfs_evict_inode,
292 	.umount_begin	= nfs_umount_begin,
293 	.show_options	= nfs_show_options,
294 	.show_stats	= nfs_show_stats,
295 	.remount_fs	= nfs_remount,
296 };
297 
298 #ifdef CONFIG_NFS_V4
299 static int nfs4_validate_text_mount_data(void *options,
300 	struct nfs_parsed_mount_data *args, const char *dev_name);
301 static int nfs4_try_mount(int flags, const char *dev_name,
302 	struct nfs_parsed_mount_data *data, struct vfsmount *mnt);
303 static int nfs4_get_sb(struct file_system_type *fs_type,
304 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
305 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
306 	int flags, const char *dev_name, void *raw_data);
307 static struct dentry *nfs4_xdev_mount(struct file_system_type *fs_type,
308 	int flags, const char *dev_name, void *raw_data);
309 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
310 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
311 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
312 	int flags, const char *dev_name, void *raw_data);
313 static void nfs4_kill_super(struct super_block *sb);
314 
315 static struct file_system_type nfs4_fs_type = {
316 	.owner		= THIS_MODULE,
317 	.name		= "nfs4",
318 	.get_sb		= nfs4_get_sb,
319 	.kill_sb	= nfs4_kill_super,
320 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
321 };
322 
323 static struct file_system_type nfs4_remote_fs_type = {
324 	.owner		= THIS_MODULE,
325 	.name		= "nfs4",
326 	.mount		= nfs4_remote_mount,
327 	.kill_sb	= nfs4_kill_super,
328 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
329 };
330 
331 struct file_system_type nfs4_xdev_fs_type = {
332 	.owner		= THIS_MODULE,
333 	.name		= "nfs4",
334 	.mount		= nfs4_xdev_mount,
335 	.kill_sb	= nfs4_kill_super,
336 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
337 };
338 
339 static struct file_system_type nfs4_remote_referral_fs_type = {
340 	.owner		= THIS_MODULE,
341 	.name		= "nfs4",
342 	.mount		= nfs4_remote_referral_mount,
343 	.kill_sb	= nfs4_kill_super,
344 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
345 };
346 
347 struct file_system_type nfs4_referral_fs_type = {
348 	.owner		= THIS_MODULE,
349 	.name		= "nfs4",
350 	.get_sb		= nfs4_referral_get_sb,
351 	.kill_sb	= nfs4_kill_super,
352 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
353 };
354 
355 static const struct super_operations nfs4_sops = {
356 	.alloc_inode	= nfs_alloc_inode,
357 	.destroy_inode	= nfs_destroy_inode,
358 	.write_inode	= nfs_write_inode,
359 	.put_super	= nfs_put_super,
360 	.statfs		= nfs_statfs,
361 	.evict_inode	= nfs4_evict_inode,
362 	.umount_begin	= nfs_umount_begin,
363 	.show_options	= nfs_show_options,
364 	.show_stats	= nfs_show_stats,
365 	.remount_fs	= nfs_remount,
366 };
367 #endif
368 
369 static struct shrinker acl_shrinker = {
370 	.shrink		= nfs_access_cache_shrinker,
371 	.seeks		= DEFAULT_SEEKS,
372 };
373 
374 /*
375  * Register the NFS filesystems
376  */
377 int __init register_nfs_fs(void)
378 {
379 	int ret;
380 
381         ret = register_filesystem(&nfs_fs_type);
382 	if (ret < 0)
383 		goto error_0;
384 
385 	ret = nfs_register_sysctl();
386 	if (ret < 0)
387 		goto error_1;
388 #ifdef CONFIG_NFS_V4
389 	ret = register_filesystem(&nfs4_fs_type);
390 	if (ret < 0)
391 		goto error_2;
392 #endif
393 	register_shrinker(&acl_shrinker);
394 	return 0;
395 
396 #ifdef CONFIG_NFS_V4
397 error_2:
398 	nfs_unregister_sysctl();
399 #endif
400 error_1:
401 	unregister_filesystem(&nfs_fs_type);
402 error_0:
403 	return ret;
404 }
405 
406 /*
407  * Unregister the NFS filesystems
408  */
409 void __exit unregister_nfs_fs(void)
410 {
411 	unregister_shrinker(&acl_shrinker);
412 #ifdef CONFIG_NFS_V4
413 	unregister_filesystem(&nfs4_fs_type);
414 #endif
415 	nfs_unregister_sysctl();
416 	unregister_filesystem(&nfs_fs_type);
417 }
418 
419 void nfs_sb_active(struct super_block *sb)
420 {
421 	struct nfs_server *server = NFS_SB(sb);
422 
423 	if (atomic_inc_return(&server->active) == 1)
424 		atomic_inc(&sb->s_active);
425 }
426 
427 void nfs_sb_deactive(struct super_block *sb)
428 {
429 	struct nfs_server *server = NFS_SB(sb);
430 
431 	if (atomic_dec_and_test(&server->active))
432 		deactivate_super(sb);
433 }
434 
435 /*
436  * Deliver file system statistics to userspace
437  */
438 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
439 {
440 	struct nfs_server *server = NFS_SB(dentry->d_sb);
441 	unsigned char blockbits;
442 	unsigned long blockres;
443 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
444 	struct nfs_fsstat res;
445 	int error = -ENOMEM;
446 
447 	res.fattr = nfs_alloc_fattr();
448 	if (res.fattr == NULL)
449 		goto out_err;
450 
451 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
452 	if (unlikely(error == -ESTALE)) {
453 		struct dentry *pd_dentry;
454 
455 		pd_dentry = dget_parent(dentry);
456 		if (pd_dentry != NULL) {
457 			nfs_zap_caches(pd_dentry->d_inode);
458 			dput(pd_dentry);
459 		}
460 	}
461 	nfs_free_fattr(res.fattr);
462 	if (error < 0)
463 		goto out_err;
464 
465 	buf->f_type = NFS_SUPER_MAGIC;
466 
467 	/*
468 	 * Current versions of glibc do not correctly handle the
469 	 * case where f_frsize != f_bsize.  Eventually we want to
470 	 * report the value of wtmult in this field.
471 	 */
472 	buf->f_frsize = dentry->d_sb->s_blocksize;
473 
474 	/*
475 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
476 	 * are reported in units of f_frsize.  Linux hasn't had
477 	 * an f_frsize field in its statfs struct until recently,
478 	 * thus historically Linux's sys_statfs reports these
479 	 * fields in units of f_bsize.
480 	 */
481 	buf->f_bsize = dentry->d_sb->s_blocksize;
482 	blockbits = dentry->d_sb->s_blocksize_bits;
483 	blockres = (1 << blockbits) - 1;
484 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
485 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
486 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
487 
488 	buf->f_files = res.tfiles;
489 	buf->f_ffree = res.afiles;
490 
491 	buf->f_namelen = server->namelen;
492 
493 	return 0;
494 
495  out_err:
496 	dprintk("%s: statfs error = %d\n", __func__, -error);
497 	return error;
498 }
499 
500 /*
501  * Map the security flavour number to a name
502  */
503 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
504 {
505 	static const struct {
506 		rpc_authflavor_t flavour;
507 		const char *str;
508 	} sec_flavours[] = {
509 		{ RPC_AUTH_NULL, "null" },
510 		{ RPC_AUTH_UNIX, "sys" },
511 		{ RPC_AUTH_GSS_KRB5, "krb5" },
512 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
513 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
514 		{ RPC_AUTH_GSS_LKEY, "lkey" },
515 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
516 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
517 		{ RPC_AUTH_GSS_SPKM, "spkm" },
518 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
519 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
520 		{ UINT_MAX, "unknown" }
521 	};
522 	int i;
523 
524 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
525 		if (sec_flavours[i].flavour == flavour)
526 			break;
527 	}
528 	return sec_flavours[i].str;
529 }
530 
531 static void nfs_show_mountd_netid(struct seq_file *m, struct nfs_server *nfss,
532 				  int showdefaults)
533 {
534 	struct sockaddr *sap = (struct sockaddr *) &nfss->mountd_address;
535 
536 	seq_printf(m, ",mountproto=");
537 	switch (sap->sa_family) {
538 	case AF_INET:
539 		switch (nfss->mountd_protocol) {
540 		case IPPROTO_UDP:
541 			seq_printf(m, RPCBIND_NETID_UDP);
542 			break;
543 		case IPPROTO_TCP:
544 			seq_printf(m, RPCBIND_NETID_TCP);
545 			break;
546 		default:
547 			if (showdefaults)
548 				seq_printf(m, "auto");
549 		}
550 		break;
551 	case AF_INET6:
552 		switch (nfss->mountd_protocol) {
553 		case IPPROTO_UDP:
554 			seq_printf(m, RPCBIND_NETID_UDP6);
555 			break;
556 		case IPPROTO_TCP:
557 			seq_printf(m, RPCBIND_NETID_TCP6);
558 			break;
559 		default:
560 			if (showdefaults)
561 				seq_printf(m, "auto");
562 		}
563 		break;
564 	default:
565 		if (showdefaults)
566 			seq_printf(m, "auto");
567 	}
568 }
569 
570 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
571 				    int showdefaults)
572 {
573 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
574 
575 	if (nfss->flags & NFS_MOUNT_LEGACY_INTERFACE)
576 		return;
577 
578 	switch (sap->sa_family) {
579 	case AF_INET: {
580 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
581 		seq_printf(m, ",mountaddr=%pI4", &sin->sin_addr.s_addr);
582 		break;
583 	}
584 	case AF_INET6: {
585 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
586 		seq_printf(m, ",mountaddr=%pI6c", &sin6->sin6_addr);
587 		break;
588 	}
589 	default:
590 		if (showdefaults)
591 			seq_printf(m, ",mountaddr=unspecified");
592 	}
593 
594 	if (nfss->mountd_version || showdefaults)
595 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
596 	if (nfss->mountd_port || showdefaults)
597 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
598 
599 	nfs_show_mountd_netid(m, nfss, showdefaults);
600 }
601 
602 #ifdef CONFIG_NFS_V4
603 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
604 				    int showdefaults)
605 {
606 	struct nfs_client *clp = nfss->nfs_client;
607 
608 	seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
609 	seq_printf(m, ",minorversion=%u", clp->cl_minorversion);
610 }
611 #else
612 static void nfs_show_nfsv4_options(struct seq_file *m, struct nfs_server *nfss,
613 				    int showdefaults)
614 {
615 }
616 #endif
617 
618 /*
619  * Describe the mount options in force on this server representation
620  */
621 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
622 				   int showdefaults)
623 {
624 	static const struct proc_nfs_info {
625 		int flag;
626 		const char *str;
627 		const char *nostr;
628 	} nfs_info[] = {
629 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
630 		{ NFS_MOUNT_POSIX, ",posix", "" },
631 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
632 		{ NFS_MOUNT_NOAC, ",noac", "" },
633 		{ NFS_MOUNT_NONLM, ",nolock", "" },
634 		{ NFS_MOUNT_NOACL, ",noacl", "" },
635 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
636 		{ NFS_MOUNT_UNSHARED, ",nosharecache", "" },
637 		{ NFS_MOUNT_NORESVPORT, ",noresvport", "" },
638 		{ 0, NULL, NULL }
639 	};
640 	const struct proc_nfs_info *nfs_infop;
641 	struct nfs_client *clp = nfss->nfs_client;
642 	u32 version = clp->rpc_ops->version;
643 	int local_flock, local_fcntl;
644 
645 	seq_printf(m, ",vers=%u", version);
646 	seq_printf(m, ",rsize=%u", nfss->rsize);
647 	seq_printf(m, ",wsize=%u", nfss->wsize);
648 	if (nfss->bsize != 0)
649 		seq_printf(m, ",bsize=%u", nfss->bsize);
650 	seq_printf(m, ",namlen=%u", nfss->namelen);
651 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
652 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
653 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
654 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
655 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
656 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
657 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
658 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
659 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
660 		if (nfss->flags & nfs_infop->flag)
661 			seq_puts(m, nfs_infop->str);
662 		else
663 			seq_puts(m, nfs_infop->nostr);
664 	}
665 	seq_printf(m, ",proto=%s",
666 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
667 	if (version == 4) {
668 		if (nfss->port != NFS_PORT)
669 			seq_printf(m, ",port=%u", nfss->port);
670 	} else
671 		if (nfss->port)
672 			seq_printf(m, ",port=%u", nfss->port);
673 
674 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
675 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
676 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
677 
678 	if (version != 4)
679 		nfs_show_mountd_options(m, nfss, showdefaults);
680 	else
681 		nfs_show_nfsv4_options(m, nfss, showdefaults);
682 
683 	if (nfss->options & NFS_OPTION_FSCACHE)
684 		seq_printf(m, ",fsc");
685 
686 	if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) {
687 		if (nfss->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
688 			seq_printf(m, ",lookupcache=none");
689 		else
690 			seq_printf(m, ",lookupcache=pos");
691 	}
692 
693 	local_flock = nfss->flags & NFS_MOUNT_LOCAL_FLOCK;
694 	local_fcntl = nfss->flags & NFS_MOUNT_LOCAL_FCNTL;
695 
696 	if (!local_flock && !local_fcntl)
697 		seq_printf(m, ",local_lock=none");
698 	else if (local_flock && local_fcntl)
699 		seq_printf(m, ",local_lock=all");
700 	else if (local_flock)
701 		seq_printf(m, ",local_lock=flock");
702 	else
703 		seq_printf(m, ",local_lock=posix");
704 }
705 
706 /*
707  * Describe the mount options on this VFS mountpoint
708  */
709 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
710 {
711 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
712 
713 	nfs_show_mount_options(m, nfss, 0);
714 
715 	seq_printf(m, ",addr=%s",
716 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
717 							RPC_DISPLAY_ADDR));
718 
719 	return 0;
720 }
721 
722 /*
723  * Present statistical information for this VFS mountpoint
724  */
725 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
726 {
727 	int i, cpu;
728 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
729 	struct rpc_auth *auth = nfss->client->cl_auth;
730 	struct nfs_iostats totals = { };
731 
732 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
733 
734 	/*
735 	 * Display all mount option settings
736 	 */
737 	seq_printf(m, "\n\topts:\t");
738 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
739 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
740 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
741 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
742 	nfs_show_mount_options(m, nfss, 1);
743 
744 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
745 
746 	seq_printf(m, "\n\tcaps:\t");
747 	seq_printf(m, "caps=0x%x", nfss->caps);
748 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
749 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
750 	seq_printf(m, ",bsize=%u", nfss->bsize);
751 	seq_printf(m, ",namlen=%u", nfss->namelen);
752 
753 #ifdef CONFIG_NFS_V4
754 	if (nfss->nfs_client->rpc_ops->version == 4) {
755 		seq_printf(m, "\n\tnfsv4:\t");
756 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
757 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
758 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
759 	}
760 #endif
761 
762 	/*
763 	 * Display security flavor in effect for this mount
764 	 */
765 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
766 	if (auth->au_flavor)
767 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
768 
769 	/*
770 	 * Display superblock I/O counters
771 	 */
772 	for_each_possible_cpu(cpu) {
773 		struct nfs_iostats *stats;
774 
775 		preempt_disable();
776 		stats = per_cpu_ptr(nfss->io_stats, cpu);
777 
778 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
779 			totals.events[i] += stats->events[i];
780 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
781 			totals.bytes[i] += stats->bytes[i];
782 #ifdef CONFIG_NFS_FSCACHE
783 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
784 			totals.fscache[i] += stats->fscache[i];
785 #endif
786 
787 		preempt_enable();
788 	}
789 
790 	seq_printf(m, "\n\tevents:\t");
791 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
792 		seq_printf(m, "%lu ", totals.events[i]);
793 	seq_printf(m, "\n\tbytes:\t");
794 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
795 		seq_printf(m, "%Lu ", totals.bytes[i]);
796 #ifdef CONFIG_NFS_FSCACHE
797 	if (nfss->options & NFS_OPTION_FSCACHE) {
798 		seq_printf(m, "\n\tfsc:\t");
799 		for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
800 			seq_printf(m, "%Lu ", totals.bytes[i]);
801 	}
802 #endif
803 	seq_printf(m, "\n");
804 
805 	rpc_print_iostats(m, nfss->client);
806 
807 	return 0;
808 }
809 
810 /*
811  * Begin unmount by attempting to remove all automounted mountpoints we added
812  * in response to xdev traversals and referrals
813  */
814 static void nfs_umount_begin(struct super_block *sb)
815 {
816 	struct nfs_server *server;
817 	struct rpc_clnt *rpc;
818 
819 	server = NFS_SB(sb);
820 	/* -EIO all pending I/O */
821 	rpc = server->client_acl;
822 	if (!IS_ERR(rpc))
823 		rpc_killall_tasks(rpc);
824 	rpc = server->client;
825 	if (!IS_ERR(rpc))
826 		rpc_killall_tasks(rpc);
827 }
828 
829 static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int version)
830 {
831 	struct nfs_parsed_mount_data *data;
832 
833 	data = kzalloc(sizeof(*data), GFP_KERNEL);
834 	if (data) {
835 		data->acregmin		= NFS_DEF_ACREGMIN;
836 		data->acregmax		= NFS_DEF_ACREGMAX;
837 		data->acdirmin		= NFS_DEF_ACDIRMIN;
838 		data->acdirmax		= NFS_DEF_ACDIRMAX;
839 		data->mount_server.port	= NFS_UNSPEC_PORT;
840 		data->nfs_server.port	= NFS_UNSPEC_PORT;
841 		data->nfs_server.protocol = XPRT_TRANSPORT_TCP;
842 		data->auth_flavors[0]	= RPC_AUTH_UNIX;
843 		data->auth_flavor_len	= 1;
844 		data->version		= version;
845 		data->minorversion	= 0;
846 	}
847 	return data;
848 }
849 
850 /*
851  * Sanity-check a server address provided by the mount command.
852  *
853  * Address family must be initialized, and address must not be
854  * the ANY address for that family.
855  */
856 static int nfs_verify_server_address(struct sockaddr *addr)
857 {
858 	switch (addr->sa_family) {
859 	case AF_INET: {
860 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
861 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
862 	}
863 	case AF_INET6: {
864 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
865 		return !ipv6_addr_any(sa);
866 	}
867 	}
868 
869 	dfprintk(MOUNT, "NFS: Invalid IP address specified\n");
870 	return 0;
871 }
872 
873 /*
874  * Select between a default port value and a user-specified port value.
875  * If a zero value is set, then autobind will be used.
876  */
877 static void nfs_set_port(struct sockaddr *sap, int *port,
878 				 const unsigned short default_port)
879 {
880 	if (*port == NFS_UNSPEC_PORT)
881 		*port = default_port;
882 
883 	rpc_set_port(sap, *port);
884 }
885 
886 /*
887  * Sanity check the NFS transport protocol.
888  *
889  */
890 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
891 {
892 	switch (mnt->nfs_server.protocol) {
893 	case XPRT_TRANSPORT_UDP:
894 	case XPRT_TRANSPORT_TCP:
895 	case XPRT_TRANSPORT_RDMA:
896 		break;
897 	default:
898 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
899 	}
900 }
901 
902 /*
903  * For text based NFSv2/v3 mounts, the mount protocol transport default
904  * settings should depend upon the specified NFS transport.
905  */
906 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
907 {
908 	nfs_validate_transport_protocol(mnt);
909 
910 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
911 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
912 			return;
913 	switch (mnt->nfs_server.protocol) {
914 	case XPRT_TRANSPORT_UDP:
915 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
916 		break;
917 	case XPRT_TRANSPORT_TCP:
918 	case XPRT_TRANSPORT_RDMA:
919 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
920 	}
921 }
922 
923 /*
924  * Parse the value of the 'sec=' option.
925  */
926 static int nfs_parse_security_flavors(char *value,
927 				      struct nfs_parsed_mount_data *mnt)
928 {
929 	substring_t args[MAX_OPT_ARGS];
930 
931 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
932 
933 	switch (match_token(value, nfs_secflavor_tokens, args)) {
934 	case Opt_sec_none:
935 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
936 		break;
937 	case Opt_sec_sys:
938 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
939 		break;
940 	case Opt_sec_krb5:
941 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
942 		break;
943 	case Opt_sec_krb5i:
944 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
945 		break;
946 	case Opt_sec_krb5p:
947 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
948 		break;
949 	case Opt_sec_lkey:
950 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
951 		break;
952 	case Opt_sec_lkeyi:
953 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
954 		break;
955 	case Opt_sec_lkeyp:
956 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
957 		break;
958 	case Opt_sec_spkm:
959 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
960 		break;
961 	case Opt_sec_spkmi:
962 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
963 		break;
964 	case Opt_sec_spkmp:
965 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
966 		break;
967 	default:
968 		return 0;
969 	}
970 
971 	mnt->auth_flavor_len = 1;
972 	return 1;
973 }
974 
975 /*
976  * Error-check and convert a string of mount options from user space into
977  * a data structure.  The whole mount string is processed; bad options are
978  * skipped as they are encountered.  If there were no errors, return 1;
979  * otherwise return 0 (zero).
980  */
981 static int nfs_parse_mount_options(char *raw,
982 				   struct nfs_parsed_mount_data *mnt)
983 {
984 	char *p, *string, *secdata;
985 	int rc, sloppy = 0, invalid_option = 0;
986 	unsigned short protofamily = AF_UNSPEC;
987 	unsigned short mountfamily = AF_UNSPEC;
988 
989 	if (!raw) {
990 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
991 		return 1;
992 	}
993 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
994 
995 	secdata = alloc_secdata();
996 	if (!secdata)
997 		goto out_nomem;
998 
999 	rc = security_sb_copy_data(raw, secdata);
1000 	if (rc)
1001 		goto out_security_failure;
1002 
1003 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
1004 	if (rc)
1005 		goto out_security_failure;
1006 
1007 	free_secdata(secdata);
1008 
1009 	while ((p = strsep(&raw, ",")) != NULL) {
1010 		substring_t args[MAX_OPT_ARGS];
1011 		unsigned long option;
1012 		int token;
1013 
1014 		if (!*p)
1015 			continue;
1016 
1017 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
1018 
1019 		token = match_token(p, nfs_mount_option_tokens, args);
1020 		switch (token) {
1021 
1022 		/*
1023 		 * boolean options:  foo/nofoo
1024 		 */
1025 		case Opt_soft:
1026 			mnt->flags |= NFS_MOUNT_SOFT;
1027 			break;
1028 		case Opt_hard:
1029 			mnt->flags &= ~NFS_MOUNT_SOFT;
1030 			break;
1031 		case Opt_posix:
1032 			mnt->flags |= NFS_MOUNT_POSIX;
1033 			break;
1034 		case Opt_noposix:
1035 			mnt->flags &= ~NFS_MOUNT_POSIX;
1036 			break;
1037 		case Opt_cto:
1038 			mnt->flags &= ~NFS_MOUNT_NOCTO;
1039 			break;
1040 		case Opt_nocto:
1041 			mnt->flags |= NFS_MOUNT_NOCTO;
1042 			break;
1043 		case Opt_ac:
1044 			mnt->flags &= ~NFS_MOUNT_NOAC;
1045 			break;
1046 		case Opt_noac:
1047 			mnt->flags |= NFS_MOUNT_NOAC;
1048 			break;
1049 		case Opt_lock:
1050 			mnt->flags &= ~NFS_MOUNT_NONLM;
1051 			mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1052 					NFS_MOUNT_LOCAL_FCNTL);
1053 			break;
1054 		case Opt_nolock:
1055 			mnt->flags |= NFS_MOUNT_NONLM;
1056 			mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1057 				       NFS_MOUNT_LOCAL_FCNTL);
1058 			break;
1059 		case Opt_v2:
1060 			mnt->flags &= ~NFS_MOUNT_VER3;
1061 			mnt->version = 2;
1062 			break;
1063 		case Opt_v3:
1064 			mnt->flags |= NFS_MOUNT_VER3;
1065 			mnt->version = 3;
1066 			break;
1067 #ifdef CONFIG_NFS_V4
1068 		case Opt_v4:
1069 			mnt->flags &= ~NFS_MOUNT_VER3;
1070 			mnt->version = 4;
1071 			break;
1072 #endif
1073 		case Opt_udp:
1074 			mnt->flags &= ~NFS_MOUNT_TCP;
1075 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1076 			break;
1077 		case Opt_tcp:
1078 			mnt->flags |= NFS_MOUNT_TCP;
1079 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1080 			break;
1081 		case Opt_rdma:
1082 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1083 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1084 			xprt_load_transport(p);
1085 			break;
1086 		case Opt_acl:
1087 			mnt->flags &= ~NFS_MOUNT_NOACL;
1088 			break;
1089 		case Opt_noacl:
1090 			mnt->flags |= NFS_MOUNT_NOACL;
1091 			break;
1092 		case Opt_rdirplus:
1093 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1094 			break;
1095 		case Opt_nordirplus:
1096 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1097 			break;
1098 		case Opt_sharecache:
1099 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1100 			break;
1101 		case Opt_nosharecache:
1102 			mnt->flags |= NFS_MOUNT_UNSHARED;
1103 			break;
1104 		case Opt_resvport:
1105 			mnt->flags &= ~NFS_MOUNT_NORESVPORT;
1106 			break;
1107 		case Opt_noresvport:
1108 			mnt->flags |= NFS_MOUNT_NORESVPORT;
1109 			break;
1110 		case Opt_fscache:
1111 			mnt->options |= NFS_OPTION_FSCACHE;
1112 			kfree(mnt->fscache_uniq);
1113 			mnt->fscache_uniq = NULL;
1114 			break;
1115 		case Opt_nofscache:
1116 			mnt->options &= ~NFS_OPTION_FSCACHE;
1117 			kfree(mnt->fscache_uniq);
1118 			mnt->fscache_uniq = NULL;
1119 			break;
1120 
1121 		/*
1122 		 * options that take numeric values
1123 		 */
1124 		case Opt_port:
1125 			string = match_strdup(args);
1126 			if (string == NULL)
1127 				goto out_nomem;
1128 			rc = strict_strtoul(string, 10, &option);
1129 			kfree(string);
1130 			if (rc != 0 || option > USHRT_MAX)
1131 				goto out_invalid_value;
1132 			mnt->nfs_server.port = option;
1133 			break;
1134 		case Opt_rsize:
1135 			string = match_strdup(args);
1136 			if (string == NULL)
1137 				goto out_nomem;
1138 			rc = strict_strtoul(string, 10, &option);
1139 			kfree(string);
1140 			if (rc != 0)
1141 				goto out_invalid_value;
1142 			mnt->rsize = option;
1143 			break;
1144 		case Opt_wsize:
1145 			string = match_strdup(args);
1146 			if (string == NULL)
1147 				goto out_nomem;
1148 			rc = strict_strtoul(string, 10, &option);
1149 			kfree(string);
1150 			if (rc != 0)
1151 				goto out_invalid_value;
1152 			mnt->wsize = option;
1153 			break;
1154 		case Opt_bsize:
1155 			string = match_strdup(args);
1156 			if (string == NULL)
1157 				goto out_nomem;
1158 			rc = strict_strtoul(string, 10, &option);
1159 			kfree(string);
1160 			if (rc != 0)
1161 				goto out_invalid_value;
1162 			mnt->bsize = option;
1163 			break;
1164 		case Opt_timeo:
1165 			string = match_strdup(args);
1166 			if (string == NULL)
1167 				goto out_nomem;
1168 			rc = strict_strtoul(string, 10, &option);
1169 			kfree(string);
1170 			if (rc != 0 || option == 0)
1171 				goto out_invalid_value;
1172 			mnt->timeo = option;
1173 			break;
1174 		case Opt_retrans:
1175 			string = match_strdup(args);
1176 			if (string == NULL)
1177 				goto out_nomem;
1178 			rc = strict_strtoul(string, 10, &option);
1179 			kfree(string);
1180 			if (rc != 0 || option == 0)
1181 				goto out_invalid_value;
1182 			mnt->retrans = option;
1183 			break;
1184 		case Opt_acregmin:
1185 			string = match_strdup(args);
1186 			if (string == NULL)
1187 				goto out_nomem;
1188 			rc = strict_strtoul(string, 10, &option);
1189 			kfree(string);
1190 			if (rc != 0)
1191 				goto out_invalid_value;
1192 			mnt->acregmin = option;
1193 			break;
1194 		case Opt_acregmax:
1195 			string = match_strdup(args);
1196 			if (string == NULL)
1197 				goto out_nomem;
1198 			rc = strict_strtoul(string, 10, &option);
1199 			kfree(string);
1200 			if (rc != 0)
1201 				goto out_invalid_value;
1202 			mnt->acregmax = option;
1203 			break;
1204 		case Opt_acdirmin:
1205 			string = match_strdup(args);
1206 			if (string == NULL)
1207 				goto out_nomem;
1208 			rc = strict_strtoul(string, 10, &option);
1209 			kfree(string);
1210 			if (rc != 0)
1211 				goto out_invalid_value;
1212 			mnt->acdirmin = option;
1213 			break;
1214 		case Opt_acdirmax:
1215 			string = match_strdup(args);
1216 			if (string == NULL)
1217 				goto out_nomem;
1218 			rc = strict_strtoul(string, 10, &option);
1219 			kfree(string);
1220 			if (rc != 0)
1221 				goto out_invalid_value;
1222 			mnt->acdirmax = option;
1223 			break;
1224 		case Opt_actimeo:
1225 			string = match_strdup(args);
1226 			if (string == NULL)
1227 				goto out_nomem;
1228 			rc = strict_strtoul(string, 10, &option);
1229 			kfree(string);
1230 			if (rc != 0)
1231 				goto out_invalid_value;
1232 			mnt->acregmin = mnt->acregmax =
1233 			mnt->acdirmin = mnt->acdirmax = option;
1234 			break;
1235 		case Opt_namelen:
1236 			string = match_strdup(args);
1237 			if (string == NULL)
1238 				goto out_nomem;
1239 			rc = strict_strtoul(string, 10, &option);
1240 			kfree(string);
1241 			if (rc != 0)
1242 				goto out_invalid_value;
1243 			mnt->namlen = option;
1244 			break;
1245 		case Opt_mountport:
1246 			string = match_strdup(args);
1247 			if (string == NULL)
1248 				goto out_nomem;
1249 			rc = strict_strtoul(string, 10, &option);
1250 			kfree(string);
1251 			if (rc != 0 || option > USHRT_MAX)
1252 				goto out_invalid_value;
1253 			mnt->mount_server.port = option;
1254 			break;
1255 		case Opt_mountvers:
1256 			string = match_strdup(args);
1257 			if (string == NULL)
1258 				goto out_nomem;
1259 			rc = strict_strtoul(string, 10, &option);
1260 			kfree(string);
1261 			if (rc != 0 ||
1262 			    option < NFS_MNT_VERSION ||
1263 			    option > NFS_MNT3_VERSION)
1264 				goto out_invalid_value;
1265 			mnt->mount_server.version = option;
1266 			break;
1267 		case Opt_nfsvers:
1268 			string = match_strdup(args);
1269 			if (string == NULL)
1270 				goto out_nomem;
1271 			rc = strict_strtoul(string, 10, &option);
1272 			kfree(string);
1273 			if (rc != 0)
1274 				goto out_invalid_value;
1275 			switch (option) {
1276 			case NFS2_VERSION:
1277 				mnt->flags &= ~NFS_MOUNT_VER3;
1278 				mnt->version = 2;
1279 				break;
1280 			case NFS3_VERSION:
1281 				mnt->flags |= NFS_MOUNT_VER3;
1282 				mnt->version = 3;
1283 				break;
1284 #ifdef CONFIG_NFS_V4
1285 			case NFS4_VERSION:
1286 				mnt->flags &= ~NFS_MOUNT_VER3;
1287 				mnt->version = 4;
1288 				break;
1289 #endif
1290 			default:
1291 				goto out_invalid_value;
1292 			}
1293 			break;
1294 		case Opt_minorversion:
1295 			string = match_strdup(args);
1296 			if (string == NULL)
1297 				goto out_nomem;
1298 			rc = strict_strtoul(string, 10, &option);
1299 			kfree(string);
1300 			if (rc != 0)
1301 				goto out_invalid_value;
1302 			if (option > NFS4_MAX_MINOR_VERSION)
1303 				goto out_invalid_value;
1304 			mnt->minorversion = option;
1305 			break;
1306 
1307 		/*
1308 		 * options that take text values
1309 		 */
1310 		case Opt_sec:
1311 			string = match_strdup(args);
1312 			if (string == NULL)
1313 				goto out_nomem;
1314 			rc = nfs_parse_security_flavors(string, mnt);
1315 			kfree(string);
1316 			if (!rc) {
1317 				dfprintk(MOUNT, "NFS:   unrecognized "
1318 						"security flavor\n");
1319 				return 0;
1320 			}
1321 			break;
1322 		case Opt_proto:
1323 			string = match_strdup(args);
1324 			if (string == NULL)
1325 				goto out_nomem;
1326 			token = match_token(string,
1327 					    nfs_xprt_protocol_tokens, args);
1328 
1329 			protofamily = AF_INET;
1330 			switch (token) {
1331 			case Opt_xprt_udp6:
1332 				protofamily = AF_INET6;
1333 			case Opt_xprt_udp:
1334 				mnt->flags &= ~NFS_MOUNT_TCP;
1335 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1336 				kfree(string);
1337 				break;
1338 			case Opt_xprt_tcp6:
1339 				protofamily = AF_INET6;
1340 			case Opt_xprt_tcp:
1341 				mnt->flags |= NFS_MOUNT_TCP;
1342 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1343 				kfree(string);
1344 				break;
1345 			case Opt_xprt_rdma:
1346 				/* vector side protocols to TCP */
1347 				mnt->flags |= NFS_MOUNT_TCP;
1348 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1349 				xprt_load_transport(string);
1350 				kfree(string);
1351 				break;
1352 			default:
1353 				dfprintk(MOUNT, "NFS:   unrecognized "
1354 						"transport protocol\n");
1355 				kfree(string);
1356 				return 0;
1357 			}
1358 			break;
1359 		case Opt_mountproto:
1360 			string = match_strdup(args);
1361 			if (string == NULL)
1362 				goto out_nomem;
1363 			token = match_token(string,
1364 					    nfs_xprt_protocol_tokens, args);
1365 			kfree(string);
1366 
1367 			mountfamily = AF_INET;
1368 			switch (token) {
1369 			case Opt_xprt_udp6:
1370 				mountfamily = AF_INET6;
1371 			case Opt_xprt_udp:
1372 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1373 				break;
1374 			case Opt_xprt_tcp6:
1375 				mountfamily = AF_INET6;
1376 			case Opt_xprt_tcp:
1377 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1378 				break;
1379 			case Opt_xprt_rdma: /* not used for side protocols */
1380 			default:
1381 				dfprintk(MOUNT, "NFS:   unrecognized "
1382 						"transport protocol\n");
1383 				return 0;
1384 			}
1385 			break;
1386 		case Opt_addr:
1387 			string = match_strdup(args);
1388 			if (string == NULL)
1389 				goto out_nomem;
1390 			mnt->nfs_server.addrlen =
1391 				rpc_pton(string, strlen(string),
1392 					(struct sockaddr *)
1393 					&mnt->nfs_server.address,
1394 					sizeof(mnt->nfs_server.address));
1395 			kfree(string);
1396 			if (mnt->nfs_server.addrlen == 0)
1397 				goto out_invalid_address;
1398 			break;
1399 		case Opt_clientaddr:
1400 			string = match_strdup(args);
1401 			if (string == NULL)
1402 				goto out_nomem;
1403 			kfree(mnt->client_address);
1404 			mnt->client_address = string;
1405 			break;
1406 		case Opt_mounthost:
1407 			string = match_strdup(args);
1408 			if (string == NULL)
1409 				goto out_nomem;
1410 			kfree(mnt->mount_server.hostname);
1411 			mnt->mount_server.hostname = string;
1412 			break;
1413 		case Opt_mountaddr:
1414 			string = match_strdup(args);
1415 			if (string == NULL)
1416 				goto out_nomem;
1417 			mnt->mount_server.addrlen =
1418 				rpc_pton(string, strlen(string),
1419 					(struct sockaddr *)
1420 					&mnt->mount_server.address,
1421 					sizeof(mnt->mount_server.address));
1422 			kfree(string);
1423 			if (mnt->mount_server.addrlen == 0)
1424 				goto out_invalid_address;
1425 			break;
1426 		case Opt_lookupcache:
1427 			string = match_strdup(args);
1428 			if (string == NULL)
1429 				goto out_nomem;
1430 			token = match_token(string,
1431 					nfs_lookupcache_tokens, args);
1432 			kfree(string);
1433 			switch (token) {
1434 				case Opt_lookupcache_all:
1435 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1436 					break;
1437 				case Opt_lookupcache_positive:
1438 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1439 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1440 					break;
1441 				case Opt_lookupcache_none:
1442 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1443 					break;
1444 				default:
1445 					dfprintk(MOUNT, "NFS:   invalid "
1446 							"lookupcache argument\n");
1447 					return 0;
1448 			};
1449 			break;
1450 		case Opt_fscache_uniq:
1451 			string = match_strdup(args);
1452 			if (string == NULL)
1453 				goto out_nomem;
1454 			kfree(mnt->fscache_uniq);
1455 			mnt->fscache_uniq = string;
1456 			mnt->options |= NFS_OPTION_FSCACHE;
1457 			break;
1458 		case Opt_local_lock:
1459 			string = match_strdup(args);
1460 			if (string == NULL)
1461 				goto out_nomem;
1462 			token = match_token(string, nfs_local_lock_tokens,
1463 					args);
1464 			kfree(string);
1465 			switch (token) {
1466 			case Opt_local_lock_all:
1467 				mnt->flags |= (NFS_MOUNT_LOCAL_FLOCK |
1468 					       NFS_MOUNT_LOCAL_FCNTL);
1469 				break;
1470 			case Opt_local_lock_flock:
1471 				mnt->flags |= NFS_MOUNT_LOCAL_FLOCK;
1472 				break;
1473 			case Opt_local_lock_posix:
1474 				mnt->flags |= NFS_MOUNT_LOCAL_FCNTL;
1475 				break;
1476 			case Opt_local_lock_none:
1477 				mnt->flags &= ~(NFS_MOUNT_LOCAL_FLOCK |
1478 						NFS_MOUNT_LOCAL_FCNTL);
1479 				break;
1480 			default:
1481 				dfprintk(MOUNT, "NFS:	invalid	"
1482 						"local_lock argument\n");
1483 				return 0;
1484 			};
1485 			break;
1486 
1487 		/*
1488 		 * Special options
1489 		 */
1490 		case Opt_sloppy:
1491 			sloppy = 1;
1492 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1493 			break;
1494 		case Opt_userspace:
1495 		case Opt_deprecated:
1496 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1497 					"'%s'\n", p);
1498 			break;
1499 
1500 		default:
1501 			invalid_option = 1;
1502 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1503 					"'%s'\n", p);
1504 		}
1505 	}
1506 
1507 	if (!sloppy && invalid_option)
1508 		return 0;
1509 
1510 	/*
1511 	 * verify that any proto=/mountproto= options match the address
1512 	 * familiies in the addr=/mountaddr= options.
1513 	 */
1514 	if (protofamily != AF_UNSPEC &&
1515 	    protofamily != mnt->nfs_server.address.ss_family)
1516 		goto out_proto_mismatch;
1517 
1518 	if (mountfamily != AF_UNSPEC) {
1519 		if (mnt->mount_server.addrlen) {
1520 			if (mountfamily != mnt->mount_server.address.ss_family)
1521 				goto out_mountproto_mismatch;
1522 		} else {
1523 			if (mountfamily != mnt->nfs_server.address.ss_family)
1524 				goto out_mountproto_mismatch;
1525 		}
1526 	}
1527 
1528 	return 1;
1529 
1530 out_mountproto_mismatch:
1531 	printk(KERN_INFO "NFS: mount server address does not match mountproto= "
1532 			 "option\n");
1533 	return 0;
1534 out_proto_mismatch:
1535 	printk(KERN_INFO "NFS: server address does not match proto= option\n");
1536 	return 0;
1537 out_invalid_address:
1538 	printk(KERN_INFO "NFS: bad IP address specified: %s\n", p);
1539 	return 0;
1540 out_invalid_value:
1541 	printk(KERN_INFO "NFS: bad mount option value specified: %s\n", p);
1542 	return 0;
1543 out_nomem:
1544 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1545 	return 0;
1546 out_security_failure:
1547 	free_secdata(secdata);
1548 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1549 	return 0;
1550 }
1551 
1552 /*
1553  * Match the requested auth flavors with the list returned by
1554  * the server.  Returns zero and sets the mount's authentication
1555  * flavor on success; returns -EACCES if server does not support
1556  * the requested flavor.
1557  */
1558 static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
1559 			     struct nfs_mount_request *request)
1560 {
1561 	unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
1562 
1563 	/*
1564 	 * Certain releases of Linux's mountd return an empty
1565 	 * flavor list.  To prevent behavioral regression with
1566 	 * these servers (ie. rejecting mounts that used to
1567 	 * succeed), revert to pre-2.6.32 behavior (no checking)
1568 	 * if the returned flavor list is empty.
1569 	 */
1570 	if (server_authlist_len == 0)
1571 		return 0;
1572 
1573 	/*
1574 	 * We avoid sophisticated negotiating here, as there are
1575 	 * plenty of cases where we can get it wrong, providing
1576 	 * either too little or too much security.
1577 	 *
1578 	 * RFC 2623, section 2.7 suggests we SHOULD prefer the
1579 	 * flavor listed first.  However, some servers list
1580 	 * AUTH_NULL first.  Our caller plants AUTH_SYS, the
1581 	 * preferred default, in args->auth_flavors[0] if user
1582 	 * didn't specify sec= mount option.
1583 	 */
1584 	for (i = 0; i < args->auth_flavor_len; i++)
1585 		for (j = 0; j < server_authlist_len; j++)
1586 			if (args->auth_flavors[i] == request->auth_flavs[j]) {
1587 				dfprintk(MOUNT, "NFS: using auth flavor %d\n",
1588 					request->auth_flavs[j]);
1589 				args->auth_flavors[0] = request->auth_flavs[j];
1590 				return 0;
1591 			}
1592 
1593 	dfprintk(MOUNT, "NFS: server does not support requested auth flavor\n");
1594 	nfs_umount(request);
1595 	return -EACCES;
1596 }
1597 
1598 /*
1599  * Use the remote server's MOUNT service to request the NFS file handle
1600  * corresponding to the provided path.
1601  */
1602 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1603 			 struct nfs_fh *root_fh)
1604 {
1605 	rpc_authflavor_t server_authlist[NFS_MAX_SECFLAVORS];
1606 	unsigned int server_authlist_len = ARRAY_SIZE(server_authlist);
1607 	struct nfs_mount_request request = {
1608 		.sap		= (struct sockaddr *)
1609 						&args->mount_server.address,
1610 		.dirpath	= args->nfs_server.export_path,
1611 		.protocol	= args->mount_server.protocol,
1612 		.fh		= root_fh,
1613 		.noresvport	= args->flags & NFS_MOUNT_NORESVPORT,
1614 		.auth_flav_len	= &server_authlist_len,
1615 		.auth_flavs	= server_authlist,
1616 	};
1617 	int status;
1618 
1619 	if (args->mount_server.version == 0) {
1620 		switch (args->version) {
1621 			default:
1622 				args->mount_server.version = NFS_MNT3_VERSION;
1623 				break;
1624 			case 2:
1625 				args->mount_server.version = NFS_MNT_VERSION;
1626 		}
1627 	}
1628 	request.version = args->mount_server.version;
1629 
1630 	if (args->mount_server.hostname)
1631 		request.hostname = args->mount_server.hostname;
1632 	else
1633 		request.hostname = args->nfs_server.hostname;
1634 
1635 	/*
1636 	 * Construct the mount server's address.
1637 	 */
1638 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1639 		memcpy(request.sap, &args->nfs_server.address,
1640 		       args->nfs_server.addrlen);
1641 		args->mount_server.addrlen = args->nfs_server.addrlen;
1642 	}
1643 	request.salen = args->mount_server.addrlen;
1644 	nfs_set_port(request.sap, &args->mount_server.port, 0);
1645 
1646 	/*
1647 	 * Now ask the mount server to map our export path
1648 	 * to a file handle.
1649 	 */
1650 	status = nfs_mount(&request);
1651 	if (status != 0) {
1652 		dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1653 				request.hostname, status);
1654 		return status;
1655 	}
1656 
1657 	/*
1658 	 * MNTv1 (NFSv2) does not support auth flavor negotiation.
1659 	 */
1660 	if (args->mount_server.version != NFS_MNT3_VERSION)
1661 		return 0;
1662 	return nfs_walk_authlist(args, &request);
1663 }
1664 
1665 static int nfs_parse_simple_hostname(const char *dev_name,
1666 				     char **hostname, size_t maxnamlen,
1667 				     char **export_path, size_t maxpathlen)
1668 {
1669 	size_t len;
1670 	char *colon, *comma;
1671 
1672 	colon = strchr(dev_name, ':');
1673 	if (colon == NULL)
1674 		goto out_bad_devname;
1675 
1676 	len = colon - dev_name;
1677 	if (len > maxnamlen)
1678 		goto out_hostname;
1679 
1680 	/* N.B. caller will free nfs_server.hostname in all cases */
1681 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1682 	if (!*hostname)
1683 		goto out_nomem;
1684 
1685 	/* kill possible hostname list: not supported */
1686 	comma = strchr(*hostname, ',');
1687 	if (comma != NULL) {
1688 		if (comma == *hostname)
1689 			goto out_bad_devname;
1690 		*comma = '\0';
1691 	}
1692 
1693 	colon++;
1694 	len = strlen(colon);
1695 	if (len > maxpathlen)
1696 		goto out_path;
1697 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1698 	if (!*export_path)
1699 		goto out_nomem;
1700 
1701 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1702 	return 0;
1703 
1704 out_bad_devname:
1705 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1706 	return -EINVAL;
1707 
1708 out_nomem:
1709 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1710 	return -ENOMEM;
1711 
1712 out_hostname:
1713 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1714 	return -ENAMETOOLONG;
1715 
1716 out_path:
1717 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1718 	return -ENAMETOOLONG;
1719 }
1720 
1721 /*
1722  * Hostname has square brackets around it because it contains one or
1723  * more colons.  We look for the first closing square bracket, and a
1724  * colon must follow it.
1725  */
1726 static int nfs_parse_protected_hostname(const char *dev_name,
1727 					char **hostname, size_t maxnamlen,
1728 					char **export_path, size_t maxpathlen)
1729 {
1730 	size_t len;
1731 	char *start, *end;
1732 
1733 	start = (char *)(dev_name + 1);
1734 
1735 	end = strchr(start, ']');
1736 	if (end == NULL)
1737 		goto out_bad_devname;
1738 	if (*(end + 1) != ':')
1739 		goto out_bad_devname;
1740 
1741 	len = end - start;
1742 	if (len > maxnamlen)
1743 		goto out_hostname;
1744 
1745 	/* N.B. caller will free nfs_server.hostname in all cases */
1746 	*hostname = kstrndup(start, len, GFP_KERNEL);
1747 	if (*hostname == NULL)
1748 		goto out_nomem;
1749 
1750 	end += 2;
1751 	len = strlen(end);
1752 	if (len > maxpathlen)
1753 		goto out_path;
1754 	*export_path = kstrndup(end, len, GFP_KERNEL);
1755 	if (!*export_path)
1756 		goto out_nomem;
1757 
1758 	return 0;
1759 
1760 out_bad_devname:
1761 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1762 	return -EINVAL;
1763 
1764 out_nomem:
1765 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1766 	return -ENOMEM;
1767 
1768 out_hostname:
1769 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1770 	return -ENAMETOOLONG;
1771 
1772 out_path:
1773 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1774 	return -ENAMETOOLONG;
1775 }
1776 
1777 /*
1778  * Split "dev_name" into "hostname:export_path".
1779  *
1780  * The leftmost colon demarks the split between the server's hostname
1781  * and the export path.  If the hostname starts with a left square
1782  * bracket, then it may contain colons.
1783  *
1784  * Note: caller frees hostname and export path, even on error.
1785  */
1786 static int nfs_parse_devname(const char *dev_name,
1787 			     char **hostname, size_t maxnamlen,
1788 			     char **export_path, size_t maxpathlen)
1789 {
1790 	if (*dev_name == '[')
1791 		return nfs_parse_protected_hostname(dev_name,
1792 						    hostname, maxnamlen,
1793 						    export_path, maxpathlen);
1794 
1795 	return nfs_parse_simple_hostname(dev_name,
1796 					 hostname, maxnamlen,
1797 					 export_path, maxpathlen);
1798 }
1799 
1800 /*
1801  * Validate the NFS2/NFS3 mount data
1802  * - fills in the mount root filehandle
1803  *
1804  * For option strings, user space handles the following behaviors:
1805  *
1806  * + DNS: mapping server host name to IP address ("addr=" option)
1807  *
1808  * + failure mode: how to behave if a mount request can't be handled
1809  *   immediately ("fg/bg" option)
1810  *
1811  * + retry: how often to retry a mount request ("retry=" option)
1812  *
1813  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1814  *   mountproto=tcp after mountproto=udp, and so on
1815  */
1816 static int nfs_validate_mount_data(void *options,
1817 				   struct nfs_parsed_mount_data *args,
1818 				   struct nfs_fh *mntfh,
1819 				   const char *dev_name)
1820 {
1821 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1822 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
1823 
1824 	if (data == NULL)
1825 		goto out_no_data;
1826 
1827 	switch (data->version) {
1828 	case 1:
1829 		data->namlen = 0;
1830 	case 2:
1831 		data->bsize = 0;
1832 	case 3:
1833 		if (data->flags & NFS_MOUNT_VER3)
1834 			goto out_no_v3;
1835 		data->root.size = NFS2_FHSIZE;
1836 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1837 	case 4:
1838 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1839 			goto out_no_sec;
1840 	case 5:
1841 		memset(data->context, 0, sizeof(data->context));
1842 	case 6:
1843 		if (data->flags & NFS_MOUNT_VER3) {
1844 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1845 				goto out_invalid_fh;
1846 			mntfh->size = data->root.size;
1847 			args->version = 3;
1848 		} else {
1849 			mntfh->size = NFS2_FHSIZE;
1850 			args->version = 2;
1851 		}
1852 
1853 
1854 		memcpy(mntfh->data, data->root.data, mntfh->size);
1855 		if (mntfh->size < sizeof(mntfh->data))
1856 			memset(mntfh->data + mntfh->size, 0,
1857 			       sizeof(mntfh->data) - mntfh->size);
1858 
1859 		/*
1860 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1861 		 * can deal with.
1862 		 */
1863 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1864 		args->flags		|= NFS_MOUNT_LEGACY_INTERFACE;
1865 		args->rsize		= data->rsize;
1866 		args->wsize		= data->wsize;
1867 		args->timeo		= data->timeo;
1868 		args->retrans		= data->retrans;
1869 		args->acregmin		= data->acregmin;
1870 		args->acregmax		= data->acregmax;
1871 		args->acdirmin		= data->acdirmin;
1872 		args->acdirmax		= data->acdirmax;
1873 
1874 		memcpy(sap, &data->addr, sizeof(data->addr));
1875 		args->nfs_server.addrlen = sizeof(data->addr);
1876 		if (!nfs_verify_server_address(sap))
1877 			goto out_no_address;
1878 
1879 		if (!(data->flags & NFS_MOUNT_TCP))
1880 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1881 		/* N.B. caller will free nfs_server.hostname in all cases */
1882 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1883 		args->namlen		= data->namlen;
1884 		args->bsize		= data->bsize;
1885 
1886 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1887 			args->auth_flavors[0] = data->pseudoflavor;
1888 		if (!args->nfs_server.hostname)
1889 			goto out_nomem;
1890 
1891 		if (!(data->flags & NFS_MOUNT_NONLM))
1892 			args->flags &= ~(NFS_MOUNT_LOCAL_FLOCK|
1893 					 NFS_MOUNT_LOCAL_FCNTL);
1894 		else
1895 			args->flags |= (NFS_MOUNT_LOCAL_FLOCK|
1896 					NFS_MOUNT_LOCAL_FCNTL);
1897 		/*
1898 		 * The legacy version 6 binary mount data from userspace has a
1899 		 * field used only to transport selinux information into the
1900 		 * the kernel.  To continue to support that functionality we
1901 		 * have a touch of selinux knowledge here in the NFS code. The
1902 		 * userspace code converted context=blah to just blah so we are
1903 		 * converting back to the full string selinux understands.
1904 		 */
1905 		if (data->context[0]){
1906 #ifdef CONFIG_SECURITY_SELINUX
1907 			int rc;
1908 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1909 			if (!opts_str)
1910 				return -ENOMEM;
1911 			strcpy(opts_str, "context=");
1912 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1913 			strcat(opts_str, &data->context[0]);
1914 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1915 			kfree(opts_str);
1916 			if (rc)
1917 				return rc;
1918 #else
1919 			return -EINVAL;
1920 #endif
1921 		}
1922 
1923 		break;
1924 	default: {
1925 		int status;
1926 
1927 		if (nfs_parse_mount_options((char *)options, args) == 0)
1928 			return -EINVAL;
1929 
1930 		if (!nfs_verify_server_address(sap))
1931 			goto out_no_address;
1932 
1933 		if (args->version == 4)
1934 #ifdef CONFIG_NFS_V4
1935 			return nfs4_validate_text_mount_data(options,
1936 							     args, dev_name);
1937 #else
1938 			goto out_v4_not_compiled;
1939 #endif
1940 
1941 		nfs_set_port(sap, &args->nfs_server.port, 0);
1942 
1943 		nfs_set_mount_transport_protocol(args);
1944 
1945 		status = nfs_parse_devname(dev_name,
1946 					   &args->nfs_server.hostname,
1947 					   PAGE_SIZE,
1948 					   &args->nfs_server.export_path,
1949 					   NFS_MAXPATHLEN);
1950 		if (!status)
1951 			status = nfs_try_mount(args, mntfh);
1952 
1953 		kfree(args->nfs_server.export_path);
1954 		args->nfs_server.export_path = NULL;
1955 
1956 		if (status)
1957 			return status;
1958 
1959 		break;
1960 		}
1961 	}
1962 
1963 #ifndef CONFIG_NFS_V3
1964 	if (args->version == 3)
1965 		goto out_v3_not_compiled;
1966 #endif /* !CONFIG_NFS_V3 */
1967 
1968 	return 0;
1969 
1970 out_no_data:
1971 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1972 	return -EINVAL;
1973 
1974 out_no_v3:
1975 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1976 		 data->version);
1977 	return -EINVAL;
1978 
1979 out_no_sec:
1980 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1981 	return -EINVAL;
1982 
1983 #ifndef CONFIG_NFS_V3
1984 out_v3_not_compiled:
1985 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1986 	return -EPROTONOSUPPORT;
1987 #endif /* !CONFIG_NFS_V3 */
1988 
1989 #ifndef CONFIG_NFS_V4
1990 out_v4_not_compiled:
1991 	dfprintk(MOUNT, "NFS: NFSv4 is not compiled into kernel\n");
1992 	return -EPROTONOSUPPORT;
1993 #endif /* !CONFIG_NFS_V4 */
1994 
1995 out_nomem:
1996 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1997 	return -ENOMEM;
1998 
1999 out_no_address:
2000 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
2001 	return -EINVAL;
2002 
2003 out_invalid_fh:
2004 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
2005 	return -EINVAL;
2006 }
2007 
2008 static int
2009 nfs_compare_remount_data(struct nfs_server *nfss,
2010 			 struct nfs_parsed_mount_data *data)
2011 {
2012 	if (data->flags != nfss->flags ||
2013 	    data->rsize != nfss->rsize ||
2014 	    data->wsize != nfss->wsize ||
2015 	    data->retrans != nfss->client->cl_timeout->to_retries ||
2016 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
2017 	    data->acregmin != nfss->acregmin / HZ ||
2018 	    data->acregmax != nfss->acregmax / HZ ||
2019 	    data->acdirmin != nfss->acdirmin / HZ ||
2020 	    data->acdirmax != nfss->acdirmax / HZ ||
2021 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
2022 	    data->nfs_server.port != nfss->port ||
2023 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
2024 	    !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,
2025 			  (struct sockaddr *)&nfss->nfs_client->cl_addr))
2026 		return -EINVAL;
2027 
2028 	return 0;
2029 }
2030 
2031 static int
2032 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
2033 {
2034 	int error;
2035 	struct nfs_server *nfss = sb->s_fs_info;
2036 	struct nfs_parsed_mount_data *data;
2037 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
2038 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
2039 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
2040 
2041 	/*
2042 	 * Userspace mount programs that send binary options generally send
2043 	 * them populated with default values. We have no way to know which
2044 	 * ones were explicitly specified. Fall back to legacy behavior and
2045 	 * just return success.
2046 	 */
2047 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
2048 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
2049 					   options->version <= 6))))
2050 		return 0;
2051 
2052 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2053 	if (data == NULL)
2054 		return -ENOMEM;
2055 
2056 	/* fill out struct with values from existing mount */
2057 	data->flags = nfss->flags;
2058 	data->rsize = nfss->rsize;
2059 	data->wsize = nfss->wsize;
2060 	data->retrans = nfss->client->cl_timeout->to_retries;
2061 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
2062 	data->acregmin = nfss->acregmin / HZ;
2063 	data->acregmax = nfss->acregmax / HZ;
2064 	data->acdirmin = nfss->acdirmin / HZ;
2065 	data->acdirmax = nfss->acdirmax / HZ;
2066 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
2067 	data->nfs_server.port = nfss->port;
2068 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
2069 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
2070 		data->nfs_server.addrlen);
2071 
2072 	/* overwrite those values with any that were specified */
2073 	error = nfs_parse_mount_options((char *)options, data);
2074 	if (error < 0)
2075 		goto out;
2076 
2077 	/* compare new mount options with old ones */
2078 	error = nfs_compare_remount_data(nfss, data);
2079 out:
2080 	kfree(data);
2081 	return error;
2082 }
2083 
2084 /*
2085  * Initialise the common bits of the superblock
2086  */
2087 static inline void nfs_initialise_sb(struct super_block *sb)
2088 {
2089 	struct nfs_server *server = NFS_SB(sb);
2090 
2091 	sb->s_magic = NFS_SUPER_MAGIC;
2092 
2093 	/* We probably want something more informative here */
2094 	snprintf(sb->s_id, sizeof(sb->s_id),
2095 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
2096 
2097 	if (sb->s_blocksize == 0)
2098 		sb->s_blocksize = nfs_block_bits(server->wsize,
2099 						 &sb->s_blocksize_bits);
2100 
2101 	if (server->flags & NFS_MOUNT_NOAC)
2102 		sb->s_flags |= MS_SYNCHRONOUS;
2103 
2104 	sb->s_bdi = &server->backing_dev_info;
2105 
2106 	nfs_super_set_maxbytes(sb, server->maxfilesize);
2107 }
2108 
2109 /*
2110  * Finish setting up an NFS2/3 superblock
2111  */
2112 static void nfs_fill_super(struct super_block *sb,
2113 			   struct nfs_parsed_mount_data *data)
2114 {
2115 	struct nfs_server *server = NFS_SB(sb);
2116 
2117 	sb->s_blocksize_bits = 0;
2118 	sb->s_blocksize = 0;
2119 	if (data->bsize)
2120 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
2121 
2122 	if (server->nfs_client->rpc_ops->version == 3) {
2123 		/* The VFS shouldn't apply the umask to mode bits. We will do
2124 		 * so ourselves when necessary.
2125 		 */
2126 		sb->s_flags |= MS_POSIXACL;
2127 		sb->s_time_gran = 1;
2128 	}
2129 
2130 	sb->s_op = &nfs_sops;
2131  	nfs_initialise_sb(sb);
2132 }
2133 
2134 /*
2135  * Finish setting up a cloned NFS2/3 superblock
2136  */
2137 static void nfs_clone_super(struct super_block *sb,
2138 			    const struct super_block *old_sb)
2139 {
2140 	struct nfs_server *server = NFS_SB(sb);
2141 
2142 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2143 	sb->s_blocksize = old_sb->s_blocksize;
2144 	sb->s_maxbytes = old_sb->s_maxbytes;
2145 
2146 	if (server->nfs_client->rpc_ops->version == 3) {
2147 		/* The VFS shouldn't apply the umask to mode bits. We will do
2148 		 * so ourselves when necessary.
2149 		 */
2150 		sb->s_flags |= MS_POSIXACL;
2151 		sb->s_time_gran = 1;
2152 	}
2153 
2154 	sb->s_op = old_sb->s_op;
2155  	nfs_initialise_sb(sb);
2156 }
2157 
2158 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
2159 {
2160 	const struct nfs_server *a = s->s_fs_info;
2161 	const struct rpc_clnt *clnt_a = a->client;
2162 	const struct rpc_clnt *clnt_b = b->client;
2163 
2164 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
2165 		goto Ebusy;
2166 	if (a->nfs_client != b->nfs_client)
2167 		goto Ebusy;
2168 	if (a->flags != b->flags)
2169 		goto Ebusy;
2170 	if (a->wsize != b->wsize)
2171 		goto Ebusy;
2172 	if (a->rsize != b->rsize)
2173 		goto Ebusy;
2174 	if (a->acregmin != b->acregmin)
2175 		goto Ebusy;
2176 	if (a->acregmax != b->acregmax)
2177 		goto Ebusy;
2178 	if (a->acdirmin != b->acdirmin)
2179 		goto Ebusy;
2180 	if (a->acdirmax != b->acdirmax)
2181 		goto Ebusy;
2182 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
2183 		goto Ebusy;
2184 	return 1;
2185 Ebusy:
2186 	return 0;
2187 }
2188 
2189 struct nfs_sb_mountdata {
2190 	struct nfs_server *server;
2191 	int mntflags;
2192 };
2193 
2194 static int nfs_set_super(struct super_block *s, void *data)
2195 {
2196 	struct nfs_sb_mountdata *sb_mntdata = data;
2197 	struct nfs_server *server = sb_mntdata->server;
2198 	int ret;
2199 
2200 	s->s_flags = sb_mntdata->mntflags;
2201 	s->s_fs_info = server;
2202 	ret = set_anon_super(s, server);
2203 	if (ret == 0)
2204 		server->s_dev = s->s_dev;
2205 	return ret;
2206 }
2207 
2208 static int nfs_compare_super_address(struct nfs_server *server1,
2209 				     struct nfs_server *server2)
2210 {
2211 	struct sockaddr *sap1, *sap2;
2212 
2213 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
2214 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
2215 
2216 	if (sap1->sa_family != sap2->sa_family)
2217 		return 0;
2218 
2219 	switch (sap1->sa_family) {
2220 	case AF_INET: {
2221 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
2222 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
2223 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
2224 			return 0;
2225 		if (sin1->sin_port != sin2->sin_port)
2226 			return 0;
2227 		break;
2228 	}
2229 	case AF_INET6: {
2230 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
2231 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
2232 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
2233 			return 0;
2234 		if (sin1->sin6_port != sin2->sin6_port)
2235 			return 0;
2236 		break;
2237 	}
2238 	default:
2239 		return 0;
2240 	}
2241 
2242 	return 1;
2243 }
2244 
2245 static int nfs_compare_super(struct super_block *sb, void *data)
2246 {
2247 	struct nfs_sb_mountdata *sb_mntdata = data;
2248 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
2249 	int mntflags = sb_mntdata->mntflags;
2250 
2251 	if (!nfs_compare_super_address(old, server))
2252 		return 0;
2253 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
2254 	if (old->flags & NFS_MOUNT_UNSHARED)
2255 		return 0;
2256 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
2257 		return 0;
2258 	return nfs_compare_mount_options(sb, server, mntflags);
2259 }
2260 
2261 static int nfs_bdi_register(struct nfs_server *server)
2262 {
2263 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
2264 }
2265 
2266 static int nfs_get_sb(struct file_system_type *fs_type,
2267 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2268 {
2269 	struct nfs_server *server = NULL;
2270 	struct super_block *s;
2271 	struct nfs_parsed_mount_data *data;
2272 	struct nfs_fh *mntfh;
2273 	struct dentry *mntroot;
2274 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2275 	struct nfs_sb_mountdata sb_mntdata = {
2276 		.mntflags = flags,
2277 	};
2278 	int error = -ENOMEM;
2279 
2280 	data = nfs_alloc_parsed_mount_data(3);
2281 	mntfh = nfs_alloc_fhandle();
2282 	if (data == NULL || mntfh == NULL)
2283 		goto out_free_fh;
2284 
2285 	security_init_mnt_opts(&data->lsm_opts);
2286 
2287 	/* Validate the mount data */
2288 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
2289 	if (error < 0)
2290 		goto out;
2291 
2292 #ifdef CONFIG_NFS_V4
2293 	if (data->version == 4) {
2294 		error = nfs4_try_mount(flags, dev_name, data, mnt);
2295 		kfree(data->client_address);
2296 		kfree(data->nfs_server.export_path);
2297 		goto out;
2298 	}
2299 #endif	/* CONFIG_NFS_V4 */
2300 
2301 	/* Get a volume representation */
2302 	server = nfs_create_server(data, mntfh);
2303 	if (IS_ERR(server)) {
2304 		error = PTR_ERR(server);
2305 		goto out;
2306 	}
2307 	sb_mntdata.server = server;
2308 
2309 	if (server->flags & NFS_MOUNT_UNSHARED)
2310 		compare_super = NULL;
2311 
2312 	/* Get a superblock - note that we may end up sharing one that already exists */
2313 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2314 	if (IS_ERR(s)) {
2315 		error = PTR_ERR(s);
2316 		goto out_err_nosb;
2317 	}
2318 
2319 	if (s->s_fs_info != server) {
2320 		nfs_free_server(server);
2321 		server = NULL;
2322 	} else {
2323 		error = nfs_bdi_register(server);
2324 		if (error)
2325 			goto error_splat_bdi;
2326 	}
2327 
2328 	if (!s->s_root) {
2329 		/* initial superblock/root creation */
2330 		nfs_fill_super(s, data);
2331 		nfs_fscache_get_super_cookie(
2332 			s, data ? data->fscache_uniq : NULL, NULL);
2333 	}
2334 
2335 	mntroot = nfs_get_root(s, mntfh);
2336 	if (IS_ERR(mntroot)) {
2337 		error = PTR_ERR(mntroot);
2338 		goto error_splat_super;
2339 	}
2340 
2341 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2342 	if (error)
2343 		goto error_splat_root;
2344 
2345 	s->s_flags |= MS_ACTIVE;
2346 	mnt->mnt_sb = s;
2347 	mnt->mnt_root = mntroot;
2348 	error = 0;
2349 
2350 out:
2351 	kfree(data->nfs_server.hostname);
2352 	kfree(data->mount_server.hostname);
2353 	kfree(data->fscache_uniq);
2354 	security_free_mnt_opts(&data->lsm_opts);
2355 out_free_fh:
2356 	nfs_free_fhandle(mntfh);
2357 	kfree(data);
2358 	return error;
2359 
2360 out_err_nosb:
2361 	nfs_free_server(server);
2362 	goto out;
2363 
2364 error_splat_root:
2365 	dput(mntroot);
2366 error_splat_super:
2367 	if (server && !s->s_root)
2368 		bdi_unregister(&server->backing_dev_info);
2369 error_splat_bdi:
2370 	deactivate_locked_super(s);
2371 	goto out;
2372 }
2373 
2374 /*
2375  * Ensure that we unregister the bdi before kill_anon_super
2376  * releases the device name
2377  */
2378 static void nfs_put_super(struct super_block *s)
2379 {
2380 	struct nfs_server *server = NFS_SB(s);
2381 
2382 	bdi_unregister(&server->backing_dev_info);
2383 }
2384 
2385 /*
2386  * Destroy an NFS2/3 superblock
2387  */
2388 static void nfs_kill_super(struct super_block *s)
2389 {
2390 	struct nfs_server *server = NFS_SB(s);
2391 
2392 	kill_anon_super(s);
2393 	nfs_fscache_release_super_cookie(s);
2394 	nfs_free_server(server);
2395 }
2396 
2397 /*
2398  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2399  */
2400 static struct dentry *
2401 nfs_xdev_mount(struct file_system_type *fs_type, int flags,
2402 		const char *dev_name, void *raw_data)
2403 {
2404 	struct nfs_clone_mount *data = raw_data;
2405 	struct super_block *s;
2406 	struct nfs_server *server;
2407 	struct dentry *mntroot;
2408 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2409 	struct nfs_sb_mountdata sb_mntdata = {
2410 		.mntflags = flags,
2411 	};
2412 	int error;
2413 
2414 	dprintk("--> nfs_xdev_mount()\n");
2415 
2416 	/* create a new volume representation */
2417 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2418 	if (IS_ERR(server)) {
2419 		error = PTR_ERR(server);
2420 		goto out_err_noserver;
2421 	}
2422 	sb_mntdata.server = server;
2423 
2424 	if (server->flags & NFS_MOUNT_UNSHARED)
2425 		compare_super = NULL;
2426 
2427 	/* Get a superblock - note that we may end up sharing one that already exists */
2428 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2429 	if (IS_ERR(s)) {
2430 		error = PTR_ERR(s);
2431 		goto out_err_nosb;
2432 	}
2433 
2434 	if (s->s_fs_info != server) {
2435 		nfs_free_server(server);
2436 		server = NULL;
2437 	} else {
2438 		error = nfs_bdi_register(server);
2439 		if (error)
2440 			goto error_splat_bdi;
2441 	}
2442 
2443 	if (!s->s_root) {
2444 		/* initial superblock/root creation */
2445 		nfs_clone_super(s, data->sb);
2446 		nfs_fscache_get_super_cookie(s, NULL, data);
2447 	}
2448 
2449 	mntroot = nfs_get_root(s, data->fh);
2450 	if (IS_ERR(mntroot)) {
2451 		error = PTR_ERR(mntroot);
2452 		goto error_splat_super;
2453 	}
2454 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2455 		dput(mntroot);
2456 		error = -ESTALE;
2457 		goto error_splat_super;
2458 	}
2459 
2460 	s->s_flags |= MS_ACTIVE;
2461 
2462 	/* clone any lsm security options from the parent to the new sb */
2463 	security_sb_clone_mnt_opts(data->sb, s);
2464 
2465 	dprintk("<-- nfs_xdev_mount() = 0\n");
2466 	return mntroot;
2467 
2468 out_err_nosb:
2469 	nfs_free_server(server);
2470 out_err_noserver:
2471 	dprintk("<-- nfs_xdev_mount() = %d [error]\n", error);
2472 	return ERR_PTR(error);
2473 
2474 error_splat_super:
2475 	if (server && !s->s_root)
2476 		bdi_unregister(&server->backing_dev_info);
2477 error_splat_bdi:
2478 	deactivate_locked_super(s);
2479 	dprintk("<-- nfs_xdev_mount() = %d [splat]\n", error);
2480 	return ERR_PTR(error);
2481 }
2482 
2483 #ifdef CONFIG_NFS_V4
2484 
2485 /*
2486  * Finish setting up a cloned NFS4 superblock
2487  */
2488 static void nfs4_clone_super(struct super_block *sb,
2489 			    const struct super_block *old_sb)
2490 {
2491 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2492 	sb->s_blocksize = old_sb->s_blocksize;
2493 	sb->s_maxbytes = old_sb->s_maxbytes;
2494 	sb->s_time_gran = 1;
2495 	sb->s_op = old_sb->s_op;
2496  	nfs_initialise_sb(sb);
2497 }
2498 
2499 /*
2500  * Set up an NFS4 superblock
2501  */
2502 static void nfs4_fill_super(struct super_block *sb)
2503 {
2504 	sb->s_time_gran = 1;
2505 	sb->s_op = &nfs4_sops;
2506 	nfs_initialise_sb(sb);
2507 }
2508 
2509 static void nfs4_validate_mount_flags(struct nfs_parsed_mount_data *args)
2510 {
2511 	args->flags &= ~(NFS_MOUNT_NONLM|NFS_MOUNT_NOACL|NFS_MOUNT_VER3|
2512 			 NFS_MOUNT_LOCAL_FLOCK|NFS_MOUNT_LOCAL_FCNTL);
2513 }
2514 
2515 static int nfs4_validate_text_mount_data(void *options,
2516 					 struct nfs_parsed_mount_data *args,
2517 					 const char *dev_name)
2518 {
2519 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2520 
2521 	nfs_set_port(sap, &args->nfs_server.port, NFS_PORT);
2522 
2523 	nfs_validate_transport_protocol(args);
2524 
2525 	nfs4_validate_mount_flags(args);
2526 
2527 	if (args->version != 4) {
2528 		dfprintk(MOUNT,
2529 			 "NFS4: Illegal mount version\n");
2530 		return -EINVAL;
2531 	}
2532 
2533 	if (args->auth_flavor_len > 1) {
2534 		dfprintk(MOUNT,
2535 			 "NFS4: Too many RPC auth flavours specified\n");
2536 		return -EINVAL;
2537 	}
2538 
2539 	if (args->client_address == NULL) {
2540 		dfprintk(MOUNT,
2541 			 "NFS4: mount program didn't pass callback address\n");
2542 		return -EINVAL;
2543 	}
2544 
2545 	return nfs_parse_devname(dev_name,
2546 				   &args->nfs_server.hostname,
2547 				   NFS4_MAXNAMLEN,
2548 				   &args->nfs_server.export_path,
2549 				   NFS4_MAXPATHLEN);
2550 }
2551 
2552 /*
2553  * Validate NFSv4 mount options
2554  */
2555 static int nfs4_validate_mount_data(void *options,
2556 				    struct nfs_parsed_mount_data *args,
2557 				    const char *dev_name)
2558 {
2559 	struct sockaddr *sap = (struct sockaddr *)&args->nfs_server.address;
2560 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2561 	char *c;
2562 
2563 	if (data == NULL)
2564 		goto out_no_data;
2565 
2566 	switch (data->version) {
2567 	case 1:
2568 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2569 			goto out_no_address;
2570 		if (data->host_addrlen == 0)
2571 			goto out_no_address;
2572 		args->nfs_server.addrlen = data->host_addrlen;
2573 		if (copy_from_user(sap, data->host_addr, data->host_addrlen))
2574 			return -EFAULT;
2575 		if (!nfs_verify_server_address(sap))
2576 			goto out_no_address;
2577 
2578 		if (data->auth_flavourlen) {
2579 			if (data->auth_flavourlen > 1)
2580 				goto out_inval_auth;
2581 			if (copy_from_user(&args->auth_flavors[0],
2582 					   data->auth_flavours,
2583 					   sizeof(args->auth_flavors[0])))
2584 				return -EFAULT;
2585 		}
2586 
2587 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2588 		if (IS_ERR(c))
2589 			return PTR_ERR(c);
2590 		args->nfs_server.hostname = c;
2591 
2592 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2593 		if (IS_ERR(c))
2594 			return PTR_ERR(c);
2595 		args->nfs_server.export_path = c;
2596 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2597 
2598 		c = strndup_user(data->client_addr.data, 16);
2599 		if (IS_ERR(c))
2600 			return PTR_ERR(c);
2601 		args->client_address = c;
2602 
2603 		/*
2604 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2605 		 * can deal with.
2606 		 */
2607 
2608 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2609 		args->rsize	= data->rsize;
2610 		args->wsize	= data->wsize;
2611 		args->timeo	= data->timeo;
2612 		args->retrans	= data->retrans;
2613 		args->acregmin	= data->acregmin;
2614 		args->acregmax	= data->acregmax;
2615 		args->acdirmin	= data->acdirmin;
2616 		args->acdirmax	= data->acdirmax;
2617 		args->nfs_server.protocol = data->proto;
2618 		nfs_validate_transport_protocol(args);
2619 
2620 		break;
2621 	default:
2622 		if (nfs_parse_mount_options((char *)options, args) == 0)
2623 			return -EINVAL;
2624 
2625 		if (!nfs_verify_server_address(sap))
2626 			return -EINVAL;
2627 
2628 		return nfs4_validate_text_mount_data(options, args, dev_name);
2629 	}
2630 
2631 	return 0;
2632 
2633 out_no_data:
2634 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2635 	return -EINVAL;
2636 
2637 out_inval_auth:
2638 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2639 		 data->auth_flavourlen);
2640 	return -EINVAL;
2641 
2642 out_no_address:
2643 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2644 	return -EINVAL;
2645 }
2646 
2647 /*
2648  * Get the superblock for the NFS4 root partition
2649  */
2650 static struct dentry *
2651 nfs4_remote_mount(struct file_system_type *fs_type, int flags,
2652 		  const char *dev_name, void *raw_data)
2653 {
2654 	struct nfs_parsed_mount_data *data = raw_data;
2655 	struct super_block *s;
2656 	struct nfs_server *server;
2657 	struct nfs_fh *mntfh;
2658 	struct dentry *mntroot;
2659 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2660 	struct nfs_sb_mountdata sb_mntdata = {
2661 		.mntflags = flags,
2662 	};
2663 	int error = -ENOMEM;
2664 
2665 	mntfh = nfs_alloc_fhandle();
2666 	if (data == NULL || mntfh == NULL)
2667 		goto out_free_fh;
2668 
2669 	security_init_mnt_opts(&data->lsm_opts);
2670 
2671 	/* Get a volume representation */
2672 	server = nfs4_create_server(data, mntfh);
2673 	if (IS_ERR(server)) {
2674 		error = PTR_ERR(server);
2675 		goto out;
2676 	}
2677 	sb_mntdata.server = server;
2678 
2679 	if (server->flags & NFS4_MOUNT_UNSHARED)
2680 		compare_super = NULL;
2681 
2682 	/* Get a superblock - note that we may end up sharing one that already exists */
2683 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2684 	if (IS_ERR(s)) {
2685 		error = PTR_ERR(s);
2686 		goto out_free;
2687 	}
2688 
2689 	if (s->s_fs_info != server) {
2690 		nfs_free_server(server);
2691 		server = NULL;
2692 	} else {
2693 		error = nfs_bdi_register(server);
2694 		if (error)
2695 			goto error_splat_bdi;
2696 	}
2697 
2698 	if (!s->s_root) {
2699 		/* initial superblock/root creation */
2700 		nfs4_fill_super(s);
2701 		nfs_fscache_get_super_cookie(
2702 			s, data ? data->fscache_uniq : NULL, NULL);
2703 	}
2704 
2705 	mntroot = nfs4_get_root(s, mntfh);
2706 	if (IS_ERR(mntroot)) {
2707 		error = PTR_ERR(mntroot);
2708 		goto error_splat_super;
2709 	}
2710 
2711 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2712 	if (error)
2713 		goto error_splat_root;
2714 
2715 	s->s_flags |= MS_ACTIVE;
2716 
2717 	security_free_mnt_opts(&data->lsm_opts);
2718 	nfs_free_fhandle(mntfh);
2719 	return mntroot;
2720 
2721 out:
2722 	security_free_mnt_opts(&data->lsm_opts);
2723 out_free_fh:
2724 	nfs_free_fhandle(mntfh);
2725 	return ERR_PTR(error);
2726 
2727 out_free:
2728 	nfs_free_server(server);
2729 	goto out;
2730 
2731 error_splat_root:
2732 	dput(mntroot);
2733 error_splat_super:
2734 	if (server && !s->s_root)
2735 		bdi_unregister(&server->backing_dev_info);
2736 error_splat_bdi:
2737 	deactivate_locked_super(s);
2738 	goto out;
2739 }
2740 
2741 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
2742 		int flags, void *data, const char *hostname)
2743 {
2744 	struct vfsmount *root_mnt;
2745 	char *root_devname;
2746 	size_t len;
2747 
2748 	len = strlen(hostname) + 3;
2749 	root_devname = kmalloc(len, GFP_KERNEL);
2750 	if (root_devname == NULL)
2751 		return ERR_PTR(-ENOMEM);
2752 	snprintf(root_devname, len, "%s:/", hostname);
2753 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
2754 	kfree(root_devname);
2755 	return root_mnt;
2756 }
2757 
2758 static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
2759 {
2760 	char *page = (char *) __get_free_page(GFP_KERNEL);
2761 	char *devname, *tmp;
2762 
2763 	if (page == NULL)
2764 		return;
2765 	devname = nfs_path(path->mnt->mnt_devname,
2766 			path->mnt->mnt_root, path->dentry,
2767 			page, PAGE_SIZE);
2768 	if (IS_ERR(devname))
2769 		goto out_freepage;
2770 	tmp = kstrdup(devname, GFP_KERNEL);
2771 	if (tmp == NULL)
2772 		goto out_freepage;
2773 	kfree(mnt->mnt_devname);
2774 	mnt->mnt_devname = tmp;
2775 out_freepage:
2776 	free_page((unsigned long)page);
2777 }
2778 
2779 struct nfs_referral_count {
2780 	struct list_head list;
2781 	const struct task_struct *task;
2782 	unsigned int referral_count;
2783 };
2784 
2785 static LIST_HEAD(nfs_referral_count_list);
2786 static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
2787 
2788 static struct nfs_referral_count *nfs_find_referral_count(void)
2789 {
2790 	struct nfs_referral_count *p;
2791 
2792 	list_for_each_entry(p, &nfs_referral_count_list, list) {
2793 		if (p->task == current)
2794 			return p;
2795 	}
2796 	return NULL;
2797 }
2798 
2799 #define NFS_MAX_NESTED_REFERRALS 2
2800 
2801 static int nfs_referral_loop_protect(void)
2802 {
2803 	struct nfs_referral_count *p, *new;
2804 	int ret = -ENOMEM;
2805 
2806 	new = kmalloc(sizeof(*new), GFP_KERNEL);
2807 	if (!new)
2808 		goto out;
2809 	new->task = current;
2810 	new->referral_count = 1;
2811 
2812 	ret = 0;
2813 	spin_lock(&nfs_referral_count_list_lock);
2814 	p = nfs_find_referral_count();
2815 	if (p != NULL) {
2816 		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
2817 			ret = -ELOOP;
2818 		else
2819 			p->referral_count++;
2820 	} else {
2821 		list_add(&new->list, &nfs_referral_count_list);
2822 		new = NULL;
2823 	}
2824 	spin_unlock(&nfs_referral_count_list_lock);
2825 	kfree(new);
2826 out:
2827 	return ret;
2828 }
2829 
2830 static void nfs_referral_loop_unprotect(void)
2831 {
2832 	struct nfs_referral_count *p;
2833 
2834 	spin_lock(&nfs_referral_count_list_lock);
2835 	p = nfs_find_referral_count();
2836 	p->referral_count--;
2837 	if (p->referral_count == 0)
2838 		list_del(&p->list);
2839 	else
2840 		p = NULL;
2841 	spin_unlock(&nfs_referral_count_list_lock);
2842 	kfree(p);
2843 }
2844 
2845 static int nfs_follow_remote_path(struct vfsmount *root_mnt,
2846 		const char *export_path, struct vfsmount *mnt_target)
2847 {
2848 	struct nameidata *nd = NULL;
2849 	struct mnt_namespace *ns_private;
2850 	struct super_block *s;
2851 	int ret;
2852 
2853 	nd = kmalloc(sizeof(*nd), GFP_KERNEL);
2854 	if (nd == NULL)
2855 		return -ENOMEM;
2856 
2857 	ns_private = create_mnt_ns(root_mnt);
2858 	ret = PTR_ERR(ns_private);
2859 	if (IS_ERR(ns_private))
2860 		goto out_mntput;
2861 
2862 	ret = nfs_referral_loop_protect();
2863 	if (ret != 0)
2864 		goto out_put_mnt_ns;
2865 
2866 	ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
2867 			export_path, LOOKUP_FOLLOW, nd);
2868 
2869 	nfs_referral_loop_unprotect();
2870 	put_mnt_ns(ns_private);
2871 
2872 	if (ret != 0)
2873 		goto out_err;
2874 
2875 	s = nd->path.mnt->mnt_sb;
2876 	atomic_inc(&s->s_active);
2877 	mnt_target->mnt_sb = s;
2878 	mnt_target->mnt_root = dget(nd->path.dentry);
2879 
2880 	/* Correct the device pathname */
2881 	nfs_fix_devname(&nd->path, mnt_target);
2882 
2883 	path_put(&nd->path);
2884 	kfree(nd);
2885 	down_write(&s->s_umount);
2886 	return 0;
2887 out_put_mnt_ns:
2888 	put_mnt_ns(ns_private);
2889 out_mntput:
2890 	mntput(root_mnt);
2891 out_err:
2892 	kfree(nd);
2893 	return ret;
2894 }
2895 
2896 static int nfs4_try_mount(int flags, const char *dev_name,
2897 			 struct nfs_parsed_mount_data *data,
2898 			 struct vfsmount *mnt)
2899 {
2900 	char *export_path;
2901 	struct vfsmount *root_mnt;
2902 	int error;
2903 
2904 	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
2905 
2906 	export_path = data->nfs_server.export_path;
2907 	data->nfs_server.export_path = "/";
2908 	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, data,
2909 			data->nfs_server.hostname);
2910 	data->nfs_server.export_path = export_path;
2911 
2912 	error = PTR_ERR(root_mnt);
2913 	if (IS_ERR(root_mnt))
2914 		goto out;
2915 
2916 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
2917 
2918 out:
2919 	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", error,
2920 			error != 0 ? " [error]" : "");
2921 	return error;
2922 }
2923 
2924 /*
2925  * Get the superblock for an NFS4 mountpoint
2926  */
2927 static int nfs4_get_sb(struct file_system_type *fs_type,
2928 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2929 {
2930 	struct nfs_parsed_mount_data *data;
2931 	int error = -ENOMEM;
2932 
2933 	data = nfs_alloc_parsed_mount_data(4);
2934 	if (data == NULL)
2935 		goto out_free_data;
2936 
2937 	/* Validate the mount data */
2938 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2939 	if (error < 0)
2940 		goto out;
2941 
2942 	error = nfs4_try_mount(flags, dev_name, data, mnt);
2943 
2944 out:
2945 	kfree(data->client_address);
2946 	kfree(data->nfs_server.export_path);
2947 	kfree(data->nfs_server.hostname);
2948 	kfree(data->fscache_uniq);
2949 out_free_data:
2950 	kfree(data);
2951 	dprintk("<-- nfs4_get_sb() = %d%s\n", error,
2952 			error != 0 ? " [error]" : "");
2953 	return error;
2954 }
2955 
2956 static void nfs4_kill_super(struct super_block *sb)
2957 {
2958 	struct nfs_server *server = NFS_SB(sb);
2959 
2960 	dprintk("--> %s\n", __func__);
2961 	nfs_super_return_all_delegations(sb);
2962 	kill_anon_super(sb);
2963 	nfs_fscache_release_super_cookie(sb);
2964 	nfs_free_server(server);
2965 	dprintk("<-- %s\n", __func__);
2966 }
2967 
2968 /*
2969  * Clone an NFS4 server record on xdev traversal (FSID-change)
2970  */
2971 static struct dentry *
2972 nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
2973 		 const char *dev_name, void *raw_data)
2974 {
2975 	struct nfs_clone_mount *data = raw_data;
2976 	struct super_block *s;
2977 	struct nfs_server *server;
2978 	struct dentry *mntroot;
2979 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2980 	struct nfs_sb_mountdata sb_mntdata = {
2981 		.mntflags = flags,
2982 	};
2983 	int error;
2984 
2985 	dprintk("--> nfs4_xdev_mount()\n");
2986 
2987 	/* create a new volume representation */
2988 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2989 	if (IS_ERR(server)) {
2990 		error = PTR_ERR(server);
2991 		goto out_err_noserver;
2992 	}
2993 	sb_mntdata.server = server;
2994 
2995 	if (server->flags & NFS4_MOUNT_UNSHARED)
2996 		compare_super = NULL;
2997 
2998 	/* Get a superblock - note that we may end up sharing one that already exists */
2999 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3000 	if (IS_ERR(s)) {
3001 		error = PTR_ERR(s);
3002 		goto out_err_nosb;
3003 	}
3004 
3005 	if (s->s_fs_info != server) {
3006 		nfs_free_server(server);
3007 		server = NULL;
3008 	} else {
3009 		error = nfs_bdi_register(server);
3010 		if (error)
3011 			goto error_splat_bdi;
3012 	}
3013 
3014 	if (!s->s_root) {
3015 		/* initial superblock/root creation */
3016 		nfs4_clone_super(s, data->sb);
3017 		nfs_fscache_get_super_cookie(s, NULL, data);
3018 	}
3019 
3020 	mntroot = nfs4_get_root(s, data->fh);
3021 	if (IS_ERR(mntroot)) {
3022 		error = PTR_ERR(mntroot);
3023 		goto error_splat_super;
3024 	}
3025 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3026 		dput(mntroot);
3027 		error = -ESTALE;
3028 		goto error_splat_super;
3029 	}
3030 
3031 	s->s_flags |= MS_ACTIVE;
3032 
3033 	security_sb_clone_mnt_opts(data->sb, s);
3034 
3035 	dprintk("<-- nfs4_xdev_mount() = 0\n");
3036 	return mntroot;
3037 
3038 out_err_nosb:
3039 	nfs_free_server(server);
3040 out_err_noserver:
3041 	dprintk("<-- nfs4_xdev_mount() = %d [error]\n", error);
3042 	return ERR_PTR(error);
3043 
3044 error_splat_super:
3045 	if (server && !s->s_root)
3046 		bdi_unregister(&server->backing_dev_info);
3047 error_splat_bdi:
3048 	deactivate_locked_super(s);
3049 	dprintk("<-- nfs4_xdev_mount() = %d [splat]\n", error);
3050 	return ERR_PTR(error);
3051 }
3052 
3053 static struct dentry *
3054 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
3055 			   const char *dev_name, void *raw_data)
3056 {
3057 	struct nfs_clone_mount *data = raw_data;
3058 	struct super_block *s;
3059 	struct nfs_server *server;
3060 	struct dentry *mntroot;
3061 	struct nfs_fh *mntfh;
3062 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
3063 	struct nfs_sb_mountdata sb_mntdata = {
3064 		.mntflags = flags,
3065 	};
3066 	int error = -ENOMEM;
3067 
3068 	dprintk("--> nfs4_referral_get_sb()\n");
3069 
3070 	mntfh = nfs_alloc_fhandle();
3071 	if (mntfh == NULL)
3072 		goto out_err_nofh;
3073 
3074 	/* create a new volume representation */
3075 	server = nfs4_create_referral_server(data, mntfh);
3076 	if (IS_ERR(server)) {
3077 		error = PTR_ERR(server);
3078 		goto out_err_noserver;
3079 	}
3080 	sb_mntdata.server = server;
3081 
3082 	if (server->flags & NFS4_MOUNT_UNSHARED)
3083 		compare_super = NULL;
3084 
3085 	/* Get a superblock - note that we may end up sharing one that already exists */
3086 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
3087 	if (IS_ERR(s)) {
3088 		error = PTR_ERR(s);
3089 		goto out_err_nosb;
3090 	}
3091 
3092 	if (s->s_fs_info != server) {
3093 		nfs_free_server(server);
3094 		server = NULL;
3095 	} else {
3096 		error = nfs_bdi_register(server);
3097 		if (error)
3098 			goto error_splat_bdi;
3099 	}
3100 
3101 	if (!s->s_root) {
3102 		/* initial superblock/root creation */
3103 		nfs4_fill_super(s);
3104 		nfs_fscache_get_super_cookie(s, NULL, data);
3105 	}
3106 
3107 	mntroot = nfs4_get_root(s, mntfh);
3108 	if (IS_ERR(mntroot)) {
3109 		error = PTR_ERR(mntroot);
3110 		goto error_splat_super;
3111 	}
3112 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
3113 		dput(mntroot);
3114 		error = -ESTALE;
3115 		goto error_splat_super;
3116 	}
3117 
3118 	s->s_flags |= MS_ACTIVE;
3119 
3120 	security_sb_clone_mnt_opts(data->sb, s);
3121 
3122 	nfs_free_fhandle(mntfh);
3123 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
3124 	return mntroot;
3125 
3126 out_err_nosb:
3127 	nfs_free_server(server);
3128 out_err_noserver:
3129 	nfs_free_fhandle(mntfh);
3130 out_err_nofh:
3131 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
3132 	return ERR_PTR(error);
3133 
3134 error_splat_super:
3135 	if (server && !s->s_root)
3136 		bdi_unregister(&server->backing_dev_info);
3137 error_splat_bdi:
3138 	deactivate_locked_super(s);
3139 	nfs_free_fhandle(mntfh);
3140 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
3141 	return ERR_PTR(error);
3142 }
3143 
3144 /*
3145  * Create an NFS4 server record on referral traversal
3146  */
3147 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
3148 		int flags, const char *dev_name, void *raw_data,
3149 		struct vfsmount *mnt)
3150 {
3151 	struct nfs_clone_mount *data = raw_data;
3152 	char *export_path;
3153 	struct vfsmount *root_mnt;
3154 	int error;
3155 
3156 	dprintk("--> nfs4_referral_get_sb()\n");
3157 
3158 	export_path = data->mnt_path;
3159 	data->mnt_path = "/";
3160 
3161 	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
3162 			flags, data, data->hostname);
3163 	data->mnt_path = export_path;
3164 
3165 	error = PTR_ERR(root_mnt);
3166 	if (IS_ERR(root_mnt))
3167 		goto out;
3168 
3169 	error = nfs_follow_remote_path(root_mnt, export_path, mnt);
3170 out:
3171 	dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
3172 			error != 0 ? " [error]" : "");
3173 	return error;
3174 }
3175 
3176 #endif /* CONFIG_NFS_V4 */
3177