xref: /openbmc/linux/fs/nfs/super.c (revision 545e4006)
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.Cox@linux.org>, 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/nfs_idmap.h>
46 #include <linux/vfs.h>
47 #include <linux/inet.h>
48 #include <linux/in6.h>
49 #include <net/ipv6.h>
50 #include <linux/netdevice.h>
51 #include <linux/nfs_xdr.h>
52 #include <linux/magic.h>
53 #include <linux/parser.h>
54 
55 #include <asm/system.h>
56 #include <asm/uaccess.h>
57 
58 #include "nfs4_fs.h"
59 #include "callback.h"
60 #include "delegation.h"
61 #include "iostat.h"
62 #include "internal.h"
63 
64 #define NFSDBG_FACILITY		NFSDBG_VFS
65 
66 enum {
67 	/* Mount options that take no arguments */
68 	Opt_soft, Opt_hard,
69 	Opt_posix, Opt_noposix,
70 	Opt_cto, Opt_nocto,
71 	Opt_ac, Opt_noac,
72 	Opt_lock, Opt_nolock,
73 	Opt_v2, Opt_v3,
74 	Opt_udp, Opt_tcp, Opt_rdma,
75 	Opt_acl, Opt_noacl,
76 	Opt_rdirplus, Opt_nordirplus,
77 	Opt_sharecache, Opt_nosharecache,
78 
79 	/* Mount options that take integer arguments */
80 	Opt_port,
81 	Opt_rsize, Opt_wsize, Opt_bsize,
82 	Opt_timeo, Opt_retrans,
83 	Opt_acregmin, Opt_acregmax,
84 	Opt_acdirmin, Opt_acdirmax,
85 	Opt_actimeo,
86 	Opt_namelen,
87 	Opt_mountport,
88 	Opt_mountvers,
89 	Opt_nfsvers,
90 
91 	/* Mount options that take string arguments */
92 	Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
93 	Opt_addr, Opt_mountaddr, Opt_clientaddr,
94 
95 	/* Special mount options */
96 	Opt_userspace, Opt_deprecated, Opt_sloppy,
97 
98 	Opt_err
99 };
100 
101 static match_table_t nfs_mount_option_tokens = {
102 	{ Opt_userspace, "bg" },
103 	{ Opt_userspace, "fg" },
104 	{ Opt_userspace, "retry=%s" },
105 
106 	{ Opt_sloppy, "sloppy" },
107 
108 	{ Opt_soft, "soft" },
109 	{ Opt_hard, "hard" },
110 	{ Opt_deprecated, "intr" },
111 	{ Opt_deprecated, "nointr" },
112 	{ Opt_posix, "posix" },
113 	{ Opt_noposix, "noposix" },
114 	{ Opt_cto, "cto" },
115 	{ Opt_nocto, "nocto" },
116 	{ Opt_ac, "ac" },
117 	{ Opt_noac, "noac" },
118 	{ Opt_lock, "lock" },
119 	{ Opt_nolock, "nolock" },
120 	{ Opt_v2, "v2" },
121 	{ Opt_v3, "v3" },
122 	{ Opt_udp, "udp" },
123 	{ Opt_tcp, "tcp" },
124 	{ Opt_rdma, "rdma" },
125 	{ Opt_acl, "acl" },
126 	{ Opt_noacl, "noacl" },
127 	{ Opt_rdirplus, "rdirplus" },
128 	{ Opt_nordirplus, "nordirplus" },
129 	{ Opt_sharecache, "sharecache" },
130 	{ Opt_nosharecache, "nosharecache" },
131 
132 	{ Opt_port, "port=%u" },
133 	{ Opt_rsize, "rsize=%u" },
134 	{ Opt_wsize, "wsize=%u" },
135 	{ Opt_bsize, "bsize=%u" },
136 	{ Opt_timeo, "timeo=%u" },
137 	{ Opt_retrans, "retrans=%u" },
138 	{ Opt_acregmin, "acregmin=%u" },
139 	{ Opt_acregmax, "acregmax=%u" },
140 	{ Opt_acdirmin, "acdirmin=%u" },
141 	{ Opt_acdirmax, "acdirmax=%u" },
142 	{ Opt_actimeo, "actimeo=%u" },
143 	{ Opt_namelen, "namlen=%u" },
144 	{ Opt_mountport, "mountport=%u" },
145 	{ Opt_mountvers, "mountvers=%u" },
146 	{ Opt_nfsvers, "nfsvers=%u" },
147 	{ Opt_nfsvers, "vers=%u" },
148 
149 	{ Opt_sec, "sec=%s" },
150 	{ Opt_proto, "proto=%s" },
151 	{ Opt_mountproto, "mountproto=%s" },
152 	{ Opt_addr, "addr=%s" },
153 	{ Opt_clientaddr, "clientaddr=%s" },
154 	{ Opt_mounthost, "mounthost=%s" },
155 	{ Opt_mountaddr, "mountaddr=%s" },
156 
157 	{ Opt_err, NULL }
158 };
159 
160 enum {
161 	Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
162 
163 	Opt_xprt_err
164 };
165 
166 static match_table_t nfs_xprt_protocol_tokens = {
167 	{ Opt_xprt_udp, "udp" },
168 	{ Opt_xprt_tcp, "tcp" },
169 	{ Opt_xprt_rdma, "rdma" },
170 
171 	{ Opt_xprt_err, NULL }
172 };
173 
174 enum {
175 	Opt_sec_none, Opt_sec_sys,
176 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
177 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
178 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
179 
180 	Opt_sec_err
181 };
182 
183 static match_table_t nfs_secflavor_tokens = {
184 	{ Opt_sec_none, "none" },
185 	{ Opt_sec_none, "null" },
186 	{ Opt_sec_sys, "sys" },
187 
188 	{ Opt_sec_krb5, "krb5" },
189 	{ Opt_sec_krb5i, "krb5i" },
190 	{ Opt_sec_krb5p, "krb5p" },
191 
192 	{ Opt_sec_lkey, "lkey" },
193 	{ Opt_sec_lkeyi, "lkeyi" },
194 	{ Opt_sec_lkeyp, "lkeyp" },
195 
196 	{ Opt_sec_spkm, "spkm3" },
197 	{ Opt_sec_spkmi, "spkm3i" },
198 	{ Opt_sec_spkmp, "spkm3p" },
199 
200 	{ Opt_sec_err, NULL }
201 };
202 
203 
204 static void nfs_umount_begin(struct super_block *);
205 static int  nfs_statfs(struct dentry *, struct kstatfs *);
206 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
207 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
208 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
209 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
210 		int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
211 static void nfs_kill_super(struct super_block *);
212 static void nfs_put_super(struct super_block *);
213 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
214 
215 static struct file_system_type nfs_fs_type = {
216 	.owner		= THIS_MODULE,
217 	.name		= "nfs",
218 	.get_sb		= nfs_get_sb,
219 	.kill_sb	= nfs_kill_super,
220 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
221 };
222 
223 struct file_system_type nfs_xdev_fs_type = {
224 	.owner		= THIS_MODULE,
225 	.name		= "nfs",
226 	.get_sb		= nfs_xdev_get_sb,
227 	.kill_sb	= nfs_kill_super,
228 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
229 };
230 
231 static const struct super_operations nfs_sops = {
232 	.alloc_inode	= nfs_alloc_inode,
233 	.destroy_inode	= nfs_destroy_inode,
234 	.write_inode	= nfs_write_inode,
235 	.put_super	= nfs_put_super,
236 	.statfs		= nfs_statfs,
237 	.clear_inode	= nfs_clear_inode,
238 	.umount_begin	= nfs_umount_begin,
239 	.show_options	= nfs_show_options,
240 	.show_stats	= nfs_show_stats,
241 	.remount_fs	= nfs_remount,
242 };
243 
244 #ifdef CONFIG_NFS_V4
245 static int nfs4_get_sb(struct file_system_type *fs_type,
246 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
247 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
248 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
249 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
250 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
251 static void nfs4_kill_super(struct super_block *sb);
252 
253 static struct file_system_type nfs4_fs_type = {
254 	.owner		= THIS_MODULE,
255 	.name		= "nfs4",
256 	.get_sb		= nfs4_get_sb,
257 	.kill_sb	= nfs4_kill_super,
258 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
259 };
260 
261 struct file_system_type nfs4_xdev_fs_type = {
262 	.owner		= THIS_MODULE,
263 	.name		= "nfs4",
264 	.get_sb		= nfs4_xdev_get_sb,
265 	.kill_sb	= nfs4_kill_super,
266 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
267 };
268 
269 struct file_system_type nfs4_referral_fs_type = {
270 	.owner		= THIS_MODULE,
271 	.name		= "nfs4",
272 	.get_sb		= nfs4_referral_get_sb,
273 	.kill_sb	= nfs4_kill_super,
274 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
275 };
276 
277 static const struct super_operations nfs4_sops = {
278 	.alloc_inode	= nfs_alloc_inode,
279 	.destroy_inode	= nfs_destroy_inode,
280 	.write_inode	= nfs_write_inode,
281 	.statfs		= nfs_statfs,
282 	.clear_inode	= nfs4_clear_inode,
283 	.umount_begin	= nfs_umount_begin,
284 	.show_options	= nfs_show_options,
285 	.show_stats	= nfs_show_stats,
286 	.remount_fs	= nfs_remount,
287 };
288 #endif
289 
290 static struct shrinker acl_shrinker = {
291 	.shrink		= nfs_access_cache_shrinker,
292 	.seeks		= DEFAULT_SEEKS,
293 };
294 
295 /*
296  * Register the NFS filesystems
297  */
298 int __init register_nfs_fs(void)
299 {
300 	int ret;
301 
302         ret = register_filesystem(&nfs_fs_type);
303 	if (ret < 0)
304 		goto error_0;
305 
306 	ret = nfs_register_sysctl();
307 	if (ret < 0)
308 		goto error_1;
309 #ifdef CONFIG_NFS_V4
310 	ret = register_filesystem(&nfs4_fs_type);
311 	if (ret < 0)
312 		goto error_2;
313 #endif
314 	register_shrinker(&acl_shrinker);
315 	return 0;
316 
317 #ifdef CONFIG_NFS_V4
318 error_2:
319 	nfs_unregister_sysctl();
320 #endif
321 error_1:
322 	unregister_filesystem(&nfs_fs_type);
323 error_0:
324 	return ret;
325 }
326 
327 /*
328  * Unregister the NFS filesystems
329  */
330 void __exit unregister_nfs_fs(void)
331 {
332 	unregister_shrinker(&acl_shrinker);
333 #ifdef CONFIG_NFS_V4
334 	unregister_filesystem(&nfs4_fs_type);
335 #endif
336 	nfs_unregister_sysctl();
337 	unregister_filesystem(&nfs_fs_type);
338 }
339 
340 void nfs_sb_active(struct nfs_server *server)
341 {
342 	atomic_inc(&server->active);
343 }
344 
345 void nfs_sb_deactive(struct nfs_server *server)
346 {
347 	if (atomic_dec_and_test(&server->active))
348 		wake_up(&server->active_wq);
349 }
350 
351 static void nfs_put_super(struct super_block *sb)
352 {
353 	struct nfs_server *server = NFS_SB(sb);
354 	/*
355 	 * Make sure there are no outstanding ops to this server.
356 	 * If so, wait for them to finish before allowing the
357 	 * unmount to continue.
358 	 */
359 	wait_event(server->active_wq, atomic_read(&server->active) == 0);
360 }
361 
362 /*
363  * Deliver file system statistics to userspace
364  */
365 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
366 {
367 	struct nfs_server *server = NFS_SB(dentry->d_sb);
368 	unsigned char blockbits;
369 	unsigned long blockres;
370 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
371 	struct nfs_fattr fattr;
372 	struct nfs_fsstat res = {
373 			.fattr = &fattr,
374 	};
375 	int error;
376 
377 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
378 	if (error < 0)
379 		goto out_err;
380 	buf->f_type = NFS_SUPER_MAGIC;
381 
382 	/*
383 	 * Current versions of glibc do not correctly handle the
384 	 * case where f_frsize != f_bsize.  Eventually we want to
385 	 * report the value of wtmult in this field.
386 	 */
387 	buf->f_frsize = dentry->d_sb->s_blocksize;
388 
389 	/*
390 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
391 	 * are reported in units of f_frsize.  Linux hasn't had
392 	 * an f_frsize field in its statfs struct until recently,
393 	 * thus historically Linux's sys_statfs reports these
394 	 * fields in units of f_bsize.
395 	 */
396 	buf->f_bsize = dentry->d_sb->s_blocksize;
397 	blockbits = dentry->d_sb->s_blocksize_bits;
398 	blockres = (1 << blockbits) - 1;
399 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
400 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
401 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
402 
403 	buf->f_files = res.tfiles;
404 	buf->f_ffree = res.afiles;
405 
406 	buf->f_namelen = server->namelen;
407 
408 	return 0;
409 
410  out_err:
411 	dprintk("%s: statfs error = %d\n", __func__, -error);
412 	return error;
413 }
414 
415 /*
416  * Map the security flavour number to a name
417  */
418 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
419 {
420 	static const struct {
421 		rpc_authflavor_t flavour;
422 		const char *str;
423 	} sec_flavours[] = {
424 		{ RPC_AUTH_NULL, "null" },
425 		{ RPC_AUTH_UNIX, "sys" },
426 		{ RPC_AUTH_GSS_KRB5, "krb5" },
427 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
428 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
429 		{ RPC_AUTH_GSS_LKEY, "lkey" },
430 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
431 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
432 		{ RPC_AUTH_GSS_SPKM, "spkm" },
433 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
434 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
435 		{ UINT_MAX, "unknown" }
436 	};
437 	int i;
438 
439 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
440 		if (sec_flavours[i].flavour == flavour)
441 			break;
442 	}
443 	return sec_flavours[i].str;
444 }
445 
446 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
447 				    int showdefaults)
448 {
449 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
450 
451 	switch (sap->sa_family) {
452 	case AF_INET: {
453 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
454 		seq_printf(m, ",mountaddr=" NIPQUAD_FMT,
455 				NIPQUAD(sin->sin_addr.s_addr));
456 		break;
457 	}
458 	case AF_INET6: {
459 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
460 		seq_printf(m, ",mountaddr=" NIP6_FMT,
461 				NIP6(sin6->sin6_addr));
462 		break;
463 	}
464 	default:
465 		if (showdefaults)
466 			seq_printf(m, ",mountaddr=unspecified");
467 	}
468 
469 	if (nfss->mountd_version || showdefaults)
470 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
471 	if (nfss->mountd_port || showdefaults)
472 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
473 
474 	switch (nfss->mountd_protocol) {
475 	case IPPROTO_UDP:
476 		seq_printf(m, ",mountproto=udp");
477 		break;
478 	case IPPROTO_TCP:
479 		seq_printf(m, ",mountproto=tcp");
480 		break;
481 	default:
482 		if (showdefaults)
483 			seq_printf(m, ",mountproto=auto");
484 	}
485 }
486 
487 /*
488  * Describe the mount options in force on this server representation
489  */
490 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
491 				   int showdefaults)
492 {
493 	static const struct proc_nfs_info {
494 		int flag;
495 		const char *str;
496 		const char *nostr;
497 	} nfs_info[] = {
498 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
499 		{ NFS_MOUNT_INTR, ",intr", ",nointr" },
500 		{ NFS_MOUNT_POSIX, ",posix", "" },
501 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
502 		{ NFS_MOUNT_NOAC, ",noac", "" },
503 		{ NFS_MOUNT_NONLM, ",nolock", "" },
504 		{ NFS_MOUNT_NOACL, ",noacl", "" },
505 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
506 		{ NFS_MOUNT_UNSHARED, ",nosharecache", ""},
507 		{ 0, NULL, NULL }
508 	};
509 	const struct proc_nfs_info *nfs_infop;
510 	struct nfs_client *clp = nfss->nfs_client;
511 	u32 version = clp->rpc_ops->version;
512 
513 	seq_printf(m, ",vers=%u", version);
514 	seq_printf(m, ",rsize=%u", nfss->rsize);
515 	seq_printf(m, ",wsize=%u", nfss->wsize);
516 	if (nfss->bsize != 0)
517 		seq_printf(m, ",bsize=%u", nfss->bsize);
518 	seq_printf(m, ",namlen=%u", nfss->namelen);
519 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
520 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
521 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
522 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
523 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
524 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
525 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
526 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
527 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
528 		if (nfss->flags & nfs_infop->flag)
529 			seq_puts(m, nfs_infop->str);
530 		else
531 			seq_puts(m, nfs_infop->nostr);
532 	}
533 	seq_printf(m, ",proto=%s",
534 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
535 	if (version == 4) {
536 		if (nfss->port != NFS_PORT)
537 			seq_printf(m, ",port=%u", nfss->port);
538 	} else
539 		if (nfss->port)
540 			seq_printf(m, ",port=%u", nfss->port);
541 
542 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
543 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
544 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
545 
546 	if (version != 4)
547 		nfs_show_mountd_options(m, nfss, showdefaults);
548 
549 #ifdef CONFIG_NFS_V4
550 	if (clp->rpc_ops->version == 4)
551 		seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
552 #endif
553 }
554 
555 /*
556  * Describe the mount options on this VFS mountpoint
557  */
558 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
559 {
560 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
561 
562 	nfs_show_mount_options(m, nfss, 0);
563 
564 	seq_printf(m, ",addr=%s",
565 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
566 							RPC_DISPLAY_ADDR));
567 
568 	return 0;
569 }
570 
571 /*
572  * Present statistical information for this VFS mountpoint
573  */
574 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
575 {
576 	int i, cpu;
577 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
578 	struct rpc_auth *auth = nfss->client->cl_auth;
579 	struct nfs_iostats totals = { };
580 
581 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
582 
583 	/*
584 	 * Display all mount option settings
585 	 */
586 	seq_printf(m, "\n\topts:\t");
587 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
588 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
589 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
590 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
591 	nfs_show_mount_options(m, nfss, 1);
592 
593 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
594 
595 	seq_printf(m, "\n\tcaps:\t");
596 	seq_printf(m, "caps=0x%x", nfss->caps);
597 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
598 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
599 	seq_printf(m, ",bsize=%u", nfss->bsize);
600 	seq_printf(m, ",namlen=%u", nfss->namelen);
601 
602 #ifdef CONFIG_NFS_V4
603 	if (nfss->nfs_client->rpc_ops->version == 4) {
604 		seq_printf(m, "\n\tnfsv4:\t");
605 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
606 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
607 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
608 	}
609 #endif
610 
611 	/*
612 	 * Display security flavor in effect for this mount
613 	 */
614 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
615 	if (auth->au_flavor)
616 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
617 
618 	/*
619 	 * Display superblock I/O counters
620 	 */
621 	for_each_possible_cpu(cpu) {
622 		struct nfs_iostats *stats;
623 
624 		preempt_disable();
625 		stats = per_cpu_ptr(nfss->io_stats, cpu);
626 
627 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
628 			totals.events[i] += stats->events[i];
629 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
630 			totals.bytes[i] += stats->bytes[i];
631 
632 		preempt_enable();
633 	}
634 
635 	seq_printf(m, "\n\tevents:\t");
636 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
637 		seq_printf(m, "%lu ", totals.events[i]);
638 	seq_printf(m, "\n\tbytes:\t");
639 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
640 		seq_printf(m, "%Lu ", totals.bytes[i]);
641 	seq_printf(m, "\n");
642 
643 	rpc_print_iostats(m, nfss->client);
644 
645 	return 0;
646 }
647 
648 /*
649  * Begin unmount by attempting to remove all automounted mountpoints we added
650  * in response to xdev traversals and referrals
651  */
652 static void nfs_umount_begin(struct super_block *sb)
653 {
654 	struct nfs_server *server = NFS_SB(sb);
655 	struct rpc_clnt *rpc;
656 
657 	/* -EIO all pending I/O */
658 	rpc = server->client_acl;
659 	if (!IS_ERR(rpc))
660 		rpc_killall_tasks(rpc);
661 	rpc = server->client;
662 	if (!IS_ERR(rpc))
663 		rpc_killall_tasks(rpc);
664 }
665 
666 /*
667  * Set the port number in an address.  Be agnostic about the address family.
668  */
669 static void nfs_set_port(struct sockaddr *sap, unsigned short port)
670 {
671 	switch (sap->sa_family) {
672 	case AF_INET: {
673 		struct sockaddr_in *ap = (struct sockaddr_in *)sap;
674 		ap->sin_port = htons(port);
675 		break;
676 	}
677 	case AF_INET6: {
678 		struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
679 		ap->sin6_port = htons(port);
680 		break;
681 	}
682 	}
683 }
684 
685 /*
686  * Sanity-check a server address provided by the mount command.
687  *
688  * Address family must be initialized, and address must not be
689  * the ANY address for that family.
690  */
691 static int nfs_verify_server_address(struct sockaddr *addr)
692 {
693 	switch (addr->sa_family) {
694 	case AF_INET: {
695 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
696 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
697 	}
698 	case AF_INET6: {
699 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
700 		return !ipv6_addr_any(sa);
701 	}
702 	}
703 
704 	return 0;
705 }
706 
707 static void nfs_parse_ipv4_address(char *string, size_t str_len,
708 				   struct sockaddr *sap, size_t *addr_len)
709 {
710 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
711 	u8 *addr = (u8 *)&sin->sin_addr.s_addr;
712 
713 	if (str_len <= INET_ADDRSTRLEN) {
714 		dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
715 				(int)str_len, string);
716 
717 		sin->sin_family = AF_INET;
718 		*addr_len = sizeof(*sin);
719 		if (in4_pton(string, str_len, addr, '\0', NULL))
720 			return;
721 	}
722 
723 	sap->sa_family = AF_UNSPEC;
724 	*addr_len = 0;
725 }
726 
727 #define IPV6_SCOPE_DELIMITER	'%'
728 
729 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
730 static void nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
731 				    const char *delim,
732 				    struct sockaddr_in6 *sin6)
733 {
734 	char *p;
735 	size_t len;
736 
737 	if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
738 		return ;
739 	if (*delim != IPV6_SCOPE_DELIMITER)
740 		return;
741 
742 	len = (string + str_len) - delim - 1;
743 	p = kstrndup(delim + 1, len, GFP_KERNEL);
744 	if (p) {
745 		unsigned long scope_id = 0;
746 		struct net_device *dev;
747 
748 		dev = dev_get_by_name(&init_net, p);
749 		if (dev != NULL) {
750 			scope_id = dev->ifindex;
751 			dev_put(dev);
752 		} else {
753 			/* scope_id is set to zero on error */
754 			strict_strtoul(p, 10, &scope_id);
755 		}
756 
757 		kfree(p);
758 		sin6->sin6_scope_id = scope_id;
759 		dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
760 	}
761 }
762 
763 static void nfs_parse_ipv6_address(char *string, size_t str_len,
764 				   struct sockaddr *sap, size_t *addr_len)
765 {
766 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
767 	u8 *addr = (u8 *)&sin6->sin6_addr.in6_u;
768 	const char *delim;
769 
770 	if (str_len <= INET6_ADDRSTRLEN) {
771 		dfprintk(MOUNT, "NFS: parsing IPv6 address %*s\n",
772 				(int)str_len, string);
773 
774 		sin6->sin6_family = AF_INET6;
775 		*addr_len = sizeof(*sin6);
776 		if (in6_pton(string, str_len, addr, IPV6_SCOPE_DELIMITER, &delim)) {
777 			nfs_parse_ipv6_scope_id(string, str_len, delim, sin6);
778 			return;
779 		}
780 	}
781 
782 	sap->sa_family = AF_UNSPEC;
783 	*addr_len = 0;
784 }
785 #else
786 static void nfs_parse_ipv6_address(char *string, size_t str_len,
787 				   struct sockaddr *sap, size_t *addr_len)
788 {
789 	sap->sa_family = AF_UNSPEC;
790 	*addr_len = 0;
791 }
792 #endif
793 
794 /*
795  * Construct a sockaddr based on the contents of a string that contains
796  * an IP address in presentation format.
797  *
798  * If there is a problem constructing the new sockaddr, set the address
799  * family to AF_UNSPEC.
800  */
801 static void nfs_parse_ip_address(char *string, size_t str_len,
802 				 struct sockaddr *sap, size_t *addr_len)
803 {
804 	unsigned int i, colons;
805 
806 	colons = 0;
807 	for (i = 0; i < str_len; i++)
808 		if (string[i] == ':')
809 			colons++;
810 
811 	if (colons >= 2)
812 		nfs_parse_ipv6_address(string, str_len, sap, addr_len);
813 	else
814 		nfs_parse_ipv4_address(string, str_len, sap, addr_len);
815 }
816 
817 /*
818  * Sanity check the NFS transport protocol.
819  *
820  */
821 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
822 {
823 	switch (mnt->nfs_server.protocol) {
824 	case XPRT_TRANSPORT_UDP:
825 	case XPRT_TRANSPORT_TCP:
826 	case XPRT_TRANSPORT_RDMA:
827 		break;
828 	default:
829 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
830 	}
831 }
832 
833 /*
834  * For text based NFSv2/v3 mounts, the mount protocol transport default
835  * settings should depend upon the specified NFS transport.
836  */
837 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
838 {
839 	nfs_validate_transport_protocol(mnt);
840 
841 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
842 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
843 			return;
844 	switch (mnt->nfs_server.protocol) {
845 	case XPRT_TRANSPORT_UDP:
846 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
847 		break;
848 	case XPRT_TRANSPORT_TCP:
849 	case XPRT_TRANSPORT_RDMA:
850 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
851 	}
852 }
853 
854 /*
855  * Parse the value of the 'sec=' option.
856  *
857  * The flavor_len setting is for v4 mounts.
858  */
859 static int nfs_parse_security_flavors(char *value,
860 				      struct nfs_parsed_mount_data *mnt)
861 {
862 	substring_t args[MAX_OPT_ARGS];
863 
864 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
865 
866 	switch (match_token(value, nfs_secflavor_tokens, args)) {
867 	case Opt_sec_none:
868 		mnt->auth_flavor_len = 0;
869 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
870 		break;
871 	case Opt_sec_sys:
872 		mnt->auth_flavor_len = 0;
873 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
874 		break;
875 	case Opt_sec_krb5:
876 		mnt->auth_flavor_len = 1;
877 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
878 		break;
879 	case Opt_sec_krb5i:
880 		mnt->auth_flavor_len = 1;
881 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
882 		break;
883 	case Opt_sec_krb5p:
884 		mnt->auth_flavor_len = 1;
885 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
886 		break;
887 	case Opt_sec_lkey:
888 		mnt->auth_flavor_len = 1;
889 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
890 		break;
891 	case Opt_sec_lkeyi:
892 		mnt->auth_flavor_len = 1;
893 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
894 		break;
895 	case Opt_sec_lkeyp:
896 		mnt->auth_flavor_len = 1;
897 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
898 		break;
899 	case Opt_sec_spkm:
900 		mnt->auth_flavor_len = 1;
901 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
902 		break;
903 	case Opt_sec_spkmi:
904 		mnt->auth_flavor_len = 1;
905 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
906 		break;
907 	case Opt_sec_spkmp:
908 		mnt->auth_flavor_len = 1;
909 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
910 		break;
911 	default:
912 		return 0;
913 	}
914 
915 	return 1;
916 }
917 
918 static void nfs_parse_invalid_value(const char *option)
919 {
920 	dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
921 }
922 
923 /*
924  * Error-check and convert a string of mount options from user space into
925  * a data structure.  The whole mount string is processed; bad options are
926  * skipped as they are encountered.  If there were no errors, return 1;
927  * otherwise return 0 (zero).
928  */
929 static int nfs_parse_mount_options(char *raw,
930 				   struct nfs_parsed_mount_data *mnt)
931 {
932 	char *p, *string, *secdata;
933 	int rc, sloppy = 0, errors = 0;
934 
935 	if (!raw) {
936 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
937 		return 1;
938 	}
939 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
940 
941 	secdata = alloc_secdata();
942 	if (!secdata)
943 		goto out_nomem;
944 
945 	rc = security_sb_copy_data(raw, secdata);
946 	if (rc)
947 		goto out_security_failure;
948 
949 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
950 	if (rc)
951 		goto out_security_failure;
952 
953 	free_secdata(secdata);
954 
955 	while ((p = strsep(&raw, ",")) != NULL) {
956 		substring_t args[MAX_OPT_ARGS];
957 		int option, token;
958 
959 		if (!*p)
960 			continue;
961 
962 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
963 
964 		token = match_token(p, nfs_mount_option_tokens, args);
965 		switch (token) {
966 
967 		/*
968 		 * boolean options:  foo/nofoo
969 		 */
970 		case Opt_soft:
971 			mnt->flags |= NFS_MOUNT_SOFT;
972 			break;
973 		case Opt_hard:
974 			mnt->flags &= ~NFS_MOUNT_SOFT;
975 			break;
976 		case Opt_posix:
977 			mnt->flags |= NFS_MOUNT_POSIX;
978 			break;
979 		case Opt_noposix:
980 			mnt->flags &= ~NFS_MOUNT_POSIX;
981 			break;
982 		case Opt_cto:
983 			mnt->flags &= ~NFS_MOUNT_NOCTO;
984 			break;
985 		case Opt_nocto:
986 			mnt->flags |= NFS_MOUNT_NOCTO;
987 			break;
988 		case Opt_ac:
989 			mnt->flags &= ~NFS_MOUNT_NOAC;
990 			break;
991 		case Opt_noac:
992 			mnt->flags |= NFS_MOUNT_NOAC;
993 			break;
994 		case Opt_lock:
995 			mnt->flags &= ~NFS_MOUNT_NONLM;
996 			break;
997 		case Opt_nolock:
998 			mnt->flags |= NFS_MOUNT_NONLM;
999 			break;
1000 		case Opt_v2:
1001 			mnt->flags &= ~NFS_MOUNT_VER3;
1002 			break;
1003 		case Opt_v3:
1004 			mnt->flags |= NFS_MOUNT_VER3;
1005 			break;
1006 		case Opt_udp:
1007 			mnt->flags &= ~NFS_MOUNT_TCP;
1008 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1009 			break;
1010 		case Opt_tcp:
1011 			mnt->flags |= NFS_MOUNT_TCP;
1012 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1013 			break;
1014 		case Opt_rdma:
1015 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1016 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1017 			break;
1018 		case Opt_acl:
1019 			mnt->flags &= ~NFS_MOUNT_NOACL;
1020 			break;
1021 		case Opt_noacl:
1022 			mnt->flags |= NFS_MOUNT_NOACL;
1023 			break;
1024 		case Opt_rdirplus:
1025 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1026 			break;
1027 		case Opt_nordirplus:
1028 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1029 			break;
1030 		case Opt_sharecache:
1031 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1032 			break;
1033 		case Opt_nosharecache:
1034 			mnt->flags |= NFS_MOUNT_UNSHARED;
1035 			break;
1036 
1037 		/*
1038 		 * options that take numeric values
1039 		 */
1040 		case Opt_port:
1041 			if (match_int(args, &option) ||
1042 			    option < 0 || option > USHORT_MAX) {
1043 				errors++;
1044 				nfs_parse_invalid_value("port");
1045 			} else
1046 				mnt->nfs_server.port = option;
1047 			break;
1048 		case Opt_rsize:
1049 			if (match_int(args, &option) || option < 0) {
1050 				errors++;
1051 				nfs_parse_invalid_value("rsize");
1052 			} else
1053 				mnt->rsize = option;
1054 			break;
1055 		case Opt_wsize:
1056 			if (match_int(args, &option) || option < 0) {
1057 				errors++;
1058 				nfs_parse_invalid_value("wsize");
1059 			} else
1060 				mnt->wsize = option;
1061 			break;
1062 		case Opt_bsize:
1063 			if (match_int(args, &option) || option < 0) {
1064 				errors++;
1065 				nfs_parse_invalid_value("bsize");
1066 			} else
1067 				mnt->bsize = option;
1068 			break;
1069 		case Opt_timeo:
1070 			if (match_int(args, &option) || option <= 0) {
1071 				errors++;
1072 				nfs_parse_invalid_value("timeo");
1073 			} else
1074 				mnt->timeo = option;
1075 			break;
1076 		case Opt_retrans:
1077 			if (match_int(args, &option) || option <= 0) {
1078 				errors++;
1079 				nfs_parse_invalid_value("retrans");
1080 			} else
1081 				mnt->retrans = option;
1082 			break;
1083 		case Opt_acregmin:
1084 			if (match_int(args, &option) || option < 0) {
1085 				errors++;
1086 				nfs_parse_invalid_value("acregmin");
1087 			} else
1088 				mnt->acregmin = option;
1089 			break;
1090 		case Opt_acregmax:
1091 			if (match_int(args, &option) || option < 0) {
1092 				errors++;
1093 				nfs_parse_invalid_value("acregmax");
1094 			} else
1095 				mnt->acregmax = option;
1096 			break;
1097 		case Opt_acdirmin:
1098 			if (match_int(args, &option) || option < 0) {
1099 				errors++;
1100 				nfs_parse_invalid_value("acdirmin");
1101 			} else
1102 				mnt->acdirmin = option;
1103 			break;
1104 		case Opt_acdirmax:
1105 			if (match_int(args, &option) || option < 0) {
1106 				errors++;
1107 				nfs_parse_invalid_value("acdirmax");
1108 			} else
1109 				mnt->acdirmax = option;
1110 			break;
1111 		case Opt_actimeo:
1112 			if (match_int(args, &option) || option < 0) {
1113 				errors++;
1114 				nfs_parse_invalid_value("actimeo");
1115 			} else
1116 				mnt->acregmin = mnt->acregmax =
1117 				mnt->acdirmin = mnt->acdirmax = option;
1118 			break;
1119 		case Opt_namelen:
1120 			if (match_int(args, &option) || option < 0) {
1121 				errors++;
1122 				nfs_parse_invalid_value("namlen");
1123 			} else
1124 				mnt->namlen = option;
1125 			break;
1126 		case Opt_mountport:
1127 			if (match_int(args, &option) ||
1128 			    option < 0 || option > USHORT_MAX) {
1129 				errors++;
1130 				nfs_parse_invalid_value("mountport");
1131 			} else
1132 				mnt->mount_server.port = option;
1133 			break;
1134 		case Opt_mountvers:
1135 			if (match_int(args, &option) ||
1136 			    option < NFS_MNT_VERSION ||
1137 			    option > NFS_MNT3_VERSION) {
1138 				errors++;
1139 				nfs_parse_invalid_value("mountvers");
1140 			} else
1141 				mnt->mount_server.version = option;
1142 			break;
1143 		case Opt_nfsvers:
1144 			if (match_int(args, &option)) {
1145 				errors++;
1146 				nfs_parse_invalid_value("nfsvers");
1147 				break;
1148 			}
1149 			switch (option) {
1150 			case NFS2_VERSION:
1151 				mnt->flags &= ~NFS_MOUNT_VER3;
1152 				break;
1153 			case NFS3_VERSION:
1154 				mnt->flags |= NFS_MOUNT_VER3;
1155 				break;
1156 			default:
1157 				errors++;
1158 				nfs_parse_invalid_value("nfsvers");
1159 			}
1160 			break;
1161 
1162 		/*
1163 		 * options that take text values
1164 		 */
1165 		case Opt_sec:
1166 			string = match_strdup(args);
1167 			if (string == NULL)
1168 				goto out_nomem;
1169 			rc = nfs_parse_security_flavors(string, mnt);
1170 			kfree(string);
1171 			if (!rc) {
1172 				errors++;
1173 				dfprintk(MOUNT, "NFS:   unrecognized "
1174 						"security flavor\n");
1175 			}
1176 			break;
1177 		case Opt_proto:
1178 			string = match_strdup(args);
1179 			if (string == NULL)
1180 				goto out_nomem;
1181 			token = match_token(string,
1182 					    nfs_xprt_protocol_tokens, args);
1183 			kfree(string);
1184 
1185 			switch (token) {
1186 			case Opt_xprt_udp:
1187 				mnt->flags &= ~NFS_MOUNT_TCP;
1188 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1189 				break;
1190 			case Opt_xprt_tcp:
1191 				mnt->flags |= NFS_MOUNT_TCP;
1192 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1193 				break;
1194 			case Opt_xprt_rdma:
1195 				/* vector side protocols to TCP */
1196 				mnt->flags |= NFS_MOUNT_TCP;
1197 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1198 				break;
1199 			default:
1200 				errors++;
1201 				dfprintk(MOUNT, "NFS:   unrecognized "
1202 						"transport protocol\n");
1203 			}
1204 			break;
1205 		case Opt_mountproto:
1206 			string = match_strdup(args);
1207 			if (string == NULL)
1208 				goto out_nomem;
1209 			token = match_token(string,
1210 					    nfs_xprt_protocol_tokens, args);
1211 			kfree(string);
1212 
1213 			switch (token) {
1214 			case Opt_xprt_udp:
1215 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1216 				break;
1217 			case Opt_xprt_tcp:
1218 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1219 				break;
1220 			case Opt_xprt_rdma: /* not used for side protocols */
1221 			default:
1222 				errors++;
1223 				dfprintk(MOUNT, "NFS:   unrecognized "
1224 						"transport protocol\n");
1225 			}
1226 			break;
1227 		case Opt_addr:
1228 			string = match_strdup(args);
1229 			if (string == NULL)
1230 				goto out_nomem;
1231 			nfs_parse_ip_address(string, strlen(string),
1232 					     (struct sockaddr *)
1233 						&mnt->nfs_server.address,
1234 					     &mnt->nfs_server.addrlen);
1235 			kfree(string);
1236 			break;
1237 		case Opt_clientaddr:
1238 			string = match_strdup(args);
1239 			if (string == NULL)
1240 				goto out_nomem;
1241 			kfree(mnt->client_address);
1242 			mnt->client_address = string;
1243 			break;
1244 		case Opt_mounthost:
1245 			string = match_strdup(args);
1246 			if (string == NULL)
1247 				goto out_nomem;
1248 			kfree(mnt->mount_server.hostname);
1249 			mnt->mount_server.hostname = string;
1250 			break;
1251 		case Opt_mountaddr:
1252 			string = match_strdup(args);
1253 			if (string == NULL)
1254 				goto out_nomem;
1255 			nfs_parse_ip_address(string, strlen(string),
1256 					     (struct sockaddr *)
1257 						&mnt->mount_server.address,
1258 					     &mnt->mount_server.addrlen);
1259 			kfree(string);
1260 			break;
1261 
1262 		/*
1263 		 * Special options
1264 		 */
1265 		case Opt_sloppy:
1266 			sloppy = 1;
1267 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1268 			break;
1269 		case Opt_userspace:
1270 		case Opt_deprecated:
1271 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1272 					"'%s'\n", p);
1273 			break;
1274 
1275 		default:
1276 			errors++;
1277 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1278 					"'%s'\n", p);
1279 		}
1280 	}
1281 
1282 	return 1;
1283 
1284 out_nomem:
1285 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1286 	return 0;
1287 out_security_failure:
1288 	free_secdata(secdata);
1289 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1290 	return 0;
1291 }
1292 
1293 /*
1294  * Use the remote server's MOUNT service to request the NFS file handle
1295  * corresponding to the provided path.
1296  */
1297 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1298 			 struct nfs_fh *root_fh)
1299 {
1300 	struct sockaddr *sap = (struct sockaddr *)&args->mount_server.address;
1301 	char *hostname;
1302 	int status;
1303 
1304 	if (args->mount_server.version == 0) {
1305 		if (args->flags & NFS_MOUNT_VER3)
1306 			args->mount_server.version = NFS_MNT3_VERSION;
1307 		else
1308 			args->mount_server.version = NFS_MNT_VERSION;
1309 	}
1310 
1311 	if (args->mount_server.hostname)
1312 		hostname = args->mount_server.hostname;
1313 	else
1314 		hostname = args->nfs_server.hostname;
1315 
1316 	/*
1317 	 * Construct the mount server's address.
1318 	 */
1319 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1320 		memcpy(sap, &args->nfs_server.address,
1321 		       args->nfs_server.addrlen);
1322 		args->mount_server.addrlen = args->nfs_server.addrlen;
1323 	}
1324 
1325 	/*
1326 	 * autobind will be used if mount_server.port == 0
1327 	 */
1328 	nfs_set_port(sap, args->mount_server.port);
1329 
1330 	/*
1331 	 * Now ask the mount server to map our export path
1332 	 * to a file handle.
1333 	 */
1334 	status = nfs_mount(sap,
1335 			   args->mount_server.addrlen,
1336 			   hostname,
1337 			   args->nfs_server.export_path,
1338 			   args->mount_server.version,
1339 			   args->mount_server.protocol,
1340 			   root_fh);
1341 	if (status == 0)
1342 		return 0;
1343 
1344 	dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1345 			hostname, status);
1346 	return status;
1347 }
1348 
1349 static int nfs_parse_simple_hostname(const char *dev_name,
1350 				     char **hostname, size_t maxnamlen,
1351 				     char **export_path, size_t maxpathlen)
1352 {
1353 	size_t len;
1354 	char *colon, *comma;
1355 
1356 	colon = strchr(dev_name, ':');
1357 	if (colon == NULL)
1358 		goto out_bad_devname;
1359 
1360 	len = colon - dev_name;
1361 	if (len > maxnamlen)
1362 		goto out_hostname;
1363 
1364 	/* N.B. caller will free nfs_server.hostname in all cases */
1365 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1366 	if (!*hostname)
1367 		goto out_nomem;
1368 
1369 	/* kill possible hostname list: not supported */
1370 	comma = strchr(*hostname, ',');
1371 	if (comma != NULL) {
1372 		if (comma == *hostname)
1373 			goto out_bad_devname;
1374 		*comma = '\0';
1375 	}
1376 
1377 	colon++;
1378 	len = strlen(colon);
1379 	if (len > maxpathlen)
1380 		goto out_path;
1381 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1382 	if (!*export_path)
1383 		goto out_nomem;
1384 
1385 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1386 	return 0;
1387 
1388 out_bad_devname:
1389 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1390 	return -EINVAL;
1391 
1392 out_nomem:
1393 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1394 	return -ENOMEM;
1395 
1396 out_hostname:
1397 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1398 	return -ENAMETOOLONG;
1399 
1400 out_path:
1401 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1402 	return -ENAMETOOLONG;
1403 }
1404 
1405 /*
1406  * Hostname has square brackets around it because it contains one or
1407  * more colons.  We look for the first closing square bracket, and a
1408  * colon must follow it.
1409  */
1410 static int nfs_parse_protected_hostname(const char *dev_name,
1411 					char **hostname, size_t maxnamlen,
1412 					char **export_path, size_t maxpathlen)
1413 {
1414 	size_t len;
1415 	char *start, *end;
1416 
1417 	start = (char *)(dev_name + 1);
1418 
1419 	end = strchr(start, ']');
1420 	if (end == NULL)
1421 		goto out_bad_devname;
1422 	if (*(end + 1) != ':')
1423 		goto out_bad_devname;
1424 
1425 	len = end - start;
1426 	if (len > maxnamlen)
1427 		goto out_hostname;
1428 
1429 	/* N.B. caller will free nfs_server.hostname in all cases */
1430 	*hostname = kstrndup(start, len, GFP_KERNEL);
1431 	if (*hostname == NULL)
1432 		goto out_nomem;
1433 
1434 	end += 2;
1435 	len = strlen(end);
1436 	if (len > maxpathlen)
1437 		goto out_path;
1438 	*export_path = kstrndup(end, len, GFP_KERNEL);
1439 	if (!*export_path)
1440 		goto out_nomem;
1441 
1442 	return 0;
1443 
1444 out_bad_devname:
1445 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1446 	return -EINVAL;
1447 
1448 out_nomem:
1449 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1450 	return -ENOMEM;
1451 
1452 out_hostname:
1453 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1454 	return -ENAMETOOLONG;
1455 
1456 out_path:
1457 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1458 	return -ENAMETOOLONG;
1459 }
1460 
1461 /*
1462  * Split "dev_name" into "hostname:export_path".
1463  *
1464  * The leftmost colon demarks the split between the server's hostname
1465  * and the export path.  If the hostname starts with a left square
1466  * bracket, then it may contain colons.
1467  *
1468  * Note: caller frees hostname and export path, even on error.
1469  */
1470 static int nfs_parse_devname(const char *dev_name,
1471 			     char **hostname, size_t maxnamlen,
1472 			     char **export_path, size_t maxpathlen)
1473 {
1474 	if (*dev_name == '[')
1475 		return nfs_parse_protected_hostname(dev_name,
1476 						    hostname, maxnamlen,
1477 						    export_path, maxpathlen);
1478 
1479 	return nfs_parse_simple_hostname(dev_name,
1480 					 hostname, maxnamlen,
1481 					 export_path, maxpathlen);
1482 }
1483 
1484 /*
1485  * Validate the NFS2/NFS3 mount data
1486  * - fills in the mount root filehandle
1487  *
1488  * For option strings, user space handles the following behaviors:
1489  *
1490  * + DNS: mapping server host name to IP address ("addr=" option)
1491  *
1492  * + failure mode: how to behave if a mount request can't be handled
1493  *   immediately ("fg/bg" option)
1494  *
1495  * + retry: how often to retry a mount request ("retry=" option)
1496  *
1497  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1498  *   mountproto=tcp after mountproto=udp, and so on
1499  */
1500 static int nfs_validate_mount_data(void *options,
1501 				   struct nfs_parsed_mount_data *args,
1502 				   struct nfs_fh *mntfh,
1503 				   const char *dev_name)
1504 {
1505 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1506 
1507 	if (data == NULL)
1508 		goto out_no_data;
1509 
1510 	args->flags		= (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1511 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
1512 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
1513 	args->acregmin		= NFS_DEF_ACREGMIN;
1514 	args->acregmax		= NFS_DEF_ACREGMAX;
1515 	args->acdirmin		= NFS_DEF_ACDIRMIN;
1516 	args->acdirmax		= NFS_DEF_ACDIRMAX;
1517 	args->mount_server.port	= 0;	/* autobind unless user sets port */
1518 	args->nfs_server.port	= 0;	/* autobind unless user sets port */
1519 	args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1520 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
1521 
1522 	switch (data->version) {
1523 	case 1:
1524 		data->namlen = 0;
1525 	case 2:
1526 		data->bsize = 0;
1527 	case 3:
1528 		if (data->flags & NFS_MOUNT_VER3)
1529 			goto out_no_v3;
1530 		data->root.size = NFS2_FHSIZE;
1531 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1532 	case 4:
1533 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1534 			goto out_no_sec;
1535 	case 5:
1536 		memset(data->context, 0, sizeof(data->context));
1537 	case 6:
1538 		if (data->flags & NFS_MOUNT_VER3) {
1539 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1540 				goto out_invalid_fh;
1541 			mntfh->size = data->root.size;
1542 		} else
1543 			mntfh->size = NFS2_FHSIZE;
1544 
1545 
1546 		memcpy(mntfh->data, data->root.data, mntfh->size);
1547 		if (mntfh->size < sizeof(mntfh->data))
1548 			memset(mntfh->data + mntfh->size, 0,
1549 			       sizeof(mntfh->data) - mntfh->size);
1550 
1551 		/*
1552 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1553 		 * can deal with.
1554 		 */
1555 		args->flags		= data->flags;
1556 		args->rsize		= data->rsize;
1557 		args->wsize		= data->wsize;
1558 		args->timeo		= data->timeo;
1559 		args->retrans		= data->retrans;
1560 		args->acregmin		= data->acregmin;
1561 		args->acregmax		= data->acregmax;
1562 		args->acdirmin		= data->acdirmin;
1563 		args->acdirmax		= data->acdirmax;
1564 
1565 		memcpy(&args->nfs_server.address, &data->addr,
1566 		       sizeof(data->addr));
1567 		args->nfs_server.addrlen = sizeof(data->addr);
1568 		if (!nfs_verify_server_address((struct sockaddr *)
1569 						&args->nfs_server.address))
1570 			goto out_no_address;
1571 
1572 		if (!(data->flags & NFS_MOUNT_TCP))
1573 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1574 		/* N.B. caller will free nfs_server.hostname in all cases */
1575 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1576 		args->namlen		= data->namlen;
1577 		args->bsize		= data->bsize;
1578 
1579 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1580 			args->auth_flavors[0] = data->pseudoflavor;
1581 		if (!args->nfs_server.hostname)
1582 			goto out_nomem;
1583 
1584 		/*
1585 		 * The legacy version 6 binary mount data from userspace has a
1586 		 * field used only to transport selinux information into the
1587 		 * the kernel.  To continue to support that functionality we
1588 		 * have a touch of selinux knowledge here in the NFS code. The
1589 		 * userspace code converted context=blah to just blah so we are
1590 		 * converting back to the full string selinux understands.
1591 		 */
1592 		if (data->context[0]){
1593 #ifdef CONFIG_SECURITY_SELINUX
1594 			int rc;
1595 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1596 			if (!opts_str)
1597 				return -ENOMEM;
1598 			strcpy(opts_str, "context=");
1599 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1600 			strcat(opts_str, &data->context[0]);
1601 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1602 			kfree(opts_str);
1603 			if (rc)
1604 				return rc;
1605 #else
1606 			return -EINVAL;
1607 #endif
1608 		}
1609 
1610 		break;
1611 	default: {
1612 		int status;
1613 
1614 		if (nfs_parse_mount_options((char *)options, args) == 0)
1615 			return -EINVAL;
1616 
1617 		if (!nfs_verify_server_address((struct sockaddr *)
1618 						&args->nfs_server.address))
1619 			goto out_no_address;
1620 
1621 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
1622 				args->nfs_server.port);
1623 
1624 		nfs_set_mount_transport_protocol(args);
1625 
1626 		status = nfs_parse_devname(dev_name,
1627 					   &args->nfs_server.hostname,
1628 					   PAGE_SIZE,
1629 					   &args->nfs_server.export_path,
1630 					   NFS_MAXPATHLEN);
1631 		if (!status)
1632 			status = nfs_try_mount(args, mntfh);
1633 
1634 		kfree(args->nfs_server.export_path);
1635 		args->nfs_server.export_path = NULL;
1636 
1637 		if (status)
1638 			return status;
1639 
1640 		break;
1641 		}
1642 	}
1643 
1644 #ifndef CONFIG_NFS_V3
1645 	if (args->flags & NFS_MOUNT_VER3)
1646 		goto out_v3_not_compiled;
1647 #endif /* !CONFIG_NFS_V3 */
1648 
1649 	return 0;
1650 
1651 out_no_data:
1652 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1653 	return -EINVAL;
1654 
1655 out_no_v3:
1656 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1657 		 data->version);
1658 	return -EINVAL;
1659 
1660 out_no_sec:
1661 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1662 	return -EINVAL;
1663 
1664 #ifndef CONFIG_NFS_V3
1665 out_v3_not_compiled:
1666 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1667 	return -EPROTONOSUPPORT;
1668 #endif /* !CONFIG_NFS_V3 */
1669 
1670 out_nomem:
1671 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1672 	return -ENOMEM;
1673 
1674 out_no_address:
1675 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1676 	return -EINVAL;
1677 
1678 out_invalid_fh:
1679 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1680 	return -EINVAL;
1681 }
1682 
1683 static int
1684 nfs_compare_remount_data(struct nfs_server *nfss,
1685 			 struct nfs_parsed_mount_data *data)
1686 {
1687 	if (data->flags != nfss->flags ||
1688 	    data->rsize != nfss->rsize ||
1689 	    data->wsize != nfss->wsize ||
1690 	    data->retrans != nfss->client->cl_timeout->to_retries ||
1691 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
1692 	    data->acregmin != nfss->acregmin / HZ ||
1693 	    data->acregmax != nfss->acregmax / HZ ||
1694 	    data->acdirmin != nfss->acdirmin / HZ ||
1695 	    data->acdirmax != nfss->acdirmax / HZ ||
1696 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1697 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1698 	    memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1699 		   data->nfs_server.addrlen) != 0)
1700 		return -EINVAL;
1701 
1702 	return 0;
1703 }
1704 
1705 static int
1706 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
1707 {
1708 	int error;
1709 	struct nfs_server *nfss = sb->s_fs_info;
1710 	struct nfs_parsed_mount_data *data;
1711 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
1712 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
1713 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
1714 
1715 	/*
1716 	 * Userspace mount programs that send binary options generally send
1717 	 * them populated with default values. We have no way to know which
1718 	 * ones were explicitly specified. Fall back to legacy behavior and
1719 	 * just return success.
1720 	 */
1721 	if ((nfsvers == 4 && options4->version == 1) ||
1722 	    (nfsvers <= 3 && options->version >= 1 &&
1723 	     options->version <= 6))
1724 		return 0;
1725 
1726 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1727 	if (data == NULL)
1728 		return -ENOMEM;
1729 
1730 	/* fill out struct with values from existing mount */
1731 	data->flags = nfss->flags;
1732 	data->rsize = nfss->rsize;
1733 	data->wsize = nfss->wsize;
1734 	data->retrans = nfss->client->cl_timeout->to_retries;
1735 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
1736 	data->acregmin = nfss->acregmin / HZ;
1737 	data->acregmax = nfss->acregmax / HZ;
1738 	data->acdirmin = nfss->acdirmin / HZ;
1739 	data->acdirmax = nfss->acdirmax / HZ;
1740 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1741 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1742 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1743 		data->nfs_server.addrlen);
1744 
1745 	/* overwrite those values with any that were specified */
1746 	error = nfs_parse_mount_options((char *)options, data);
1747 	if (error < 0)
1748 		goto out;
1749 
1750 	/* compare new mount options with old ones */
1751 	error = nfs_compare_remount_data(nfss, data);
1752 out:
1753 	kfree(data);
1754 	return error;
1755 }
1756 
1757 /*
1758  * Initialise the common bits of the superblock
1759  */
1760 static inline void nfs_initialise_sb(struct super_block *sb)
1761 {
1762 	struct nfs_server *server = NFS_SB(sb);
1763 
1764 	sb->s_magic = NFS_SUPER_MAGIC;
1765 
1766 	/* We probably want something more informative here */
1767 	snprintf(sb->s_id, sizeof(sb->s_id),
1768 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1769 
1770 	if (sb->s_blocksize == 0)
1771 		sb->s_blocksize = nfs_block_bits(server->wsize,
1772 						 &sb->s_blocksize_bits);
1773 
1774 	if (server->flags & NFS_MOUNT_NOAC)
1775 		sb->s_flags |= MS_SYNCHRONOUS;
1776 
1777 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1778 }
1779 
1780 /*
1781  * Finish setting up an NFS2/3 superblock
1782  */
1783 static void nfs_fill_super(struct super_block *sb,
1784 			   struct nfs_parsed_mount_data *data)
1785 {
1786 	struct nfs_server *server = NFS_SB(sb);
1787 
1788 	sb->s_blocksize_bits = 0;
1789 	sb->s_blocksize = 0;
1790 	if (data->bsize)
1791 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1792 
1793 	if (server->flags & NFS_MOUNT_VER3) {
1794 		/* The VFS shouldn't apply the umask to mode bits. We will do
1795 		 * so ourselves when necessary.
1796 		 */
1797 		sb->s_flags |= MS_POSIXACL;
1798 		sb->s_time_gran = 1;
1799 	}
1800 
1801 	sb->s_op = &nfs_sops;
1802  	nfs_initialise_sb(sb);
1803 }
1804 
1805 /*
1806  * Finish setting up a cloned NFS2/3 superblock
1807  */
1808 static void nfs_clone_super(struct super_block *sb,
1809 			    const struct super_block *old_sb)
1810 {
1811 	struct nfs_server *server = NFS_SB(sb);
1812 
1813 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1814 	sb->s_blocksize = old_sb->s_blocksize;
1815 	sb->s_maxbytes = old_sb->s_maxbytes;
1816 
1817 	if (server->flags & NFS_MOUNT_VER3) {
1818 		/* The VFS shouldn't apply the umask to mode bits. We will do
1819 		 * so ourselves when necessary.
1820 		 */
1821 		sb->s_flags |= MS_POSIXACL;
1822 		sb->s_time_gran = 1;
1823 	}
1824 
1825 	sb->s_op = old_sb->s_op;
1826  	nfs_initialise_sb(sb);
1827 }
1828 
1829 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1830 
1831 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1832 {
1833 	const struct nfs_server *a = s->s_fs_info;
1834 	const struct rpc_clnt *clnt_a = a->client;
1835 	const struct rpc_clnt *clnt_b = b->client;
1836 
1837 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1838 		goto Ebusy;
1839 	if (a->nfs_client != b->nfs_client)
1840 		goto Ebusy;
1841 	if (a->flags != b->flags)
1842 		goto Ebusy;
1843 	if (a->wsize != b->wsize)
1844 		goto Ebusy;
1845 	if (a->rsize != b->rsize)
1846 		goto Ebusy;
1847 	if (a->acregmin != b->acregmin)
1848 		goto Ebusy;
1849 	if (a->acregmax != b->acregmax)
1850 		goto Ebusy;
1851 	if (a->acdirmin != b->acdirmin)
1852 		goto Ebusy;
1853 	if (a->acdirmax != b->acdirmax)
1854 		goto Ebusy;
1855 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1856 		goto Ebusy;
1857 	return 1;
1858 Ebusy:
1859 	return 0;
1860 }
1861 
1862 struct nfs_sb_mountdata {
1863 	struct nfs_server *server;
1864 	int mntflags;
1865 };
1866 
1867 static int nfs_set_super(struct super_block *s, void *data)
1868 {
1869 	struct nfs_sb_mountdata *sb_mntdata = data;
1870 	struct nfs_server *server = sb_mntdata->server;
1871 	int ret;
1872 
1873 	s->s_flags = sb_mntdata->mntflags;
1874 	s->s_fs_info = server;
1875 	ret = set_anon_super(s, server);
1876 	if (ret == 0)
1877 		server->s_dev = s->s_dev;
1878 	return ret;
1879 }
1880 
1881 static int nfs_compare_super_address(struct nfs_server *server1,
1882 				     struct nfs_server *server2)
1883 {
1884 	struct sockaddr *sap1, *sap2;
1885 
1886 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1887 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1888 
1889 	if (sap1->sa_family != sap2->sa_family)
1890 		return 0;
1891 
1892 	switch (sap1->sa_family) {
1893 	case AF_INET: {
1894 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1895 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1896 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1897 			return 0;
1898 		if (sin1->sin_port != sin2->sin_port)
1899 			return 0;
1900 		break;
1901 	}
1902 	case AF_INET6: {
1903 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1904 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1905 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1906 			return 0;
1907 		if (sin1->sin6_port != sin2->sin6_port)
1908 			return 0;
1909 		break;
1910 	}
1911 	default:
1912 		return 0;
1913 	}
1914 
1915 	return 1;
1916 }
1917 
1918 static int nfs_compare_super(struct super_block *sb, void *data)
1919 {
1920 	struct nfs_sb_mountdata *sb_mntdata = data;
1921 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1922 	int mntflags = sb_mntdata->mntflags;
1923 
1924 	if (!nfs_compare_super_address(old, server))
1925 		return 0;
1926 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1927 	if (old->flags & NFS_MOUNT_UNSHARED)
1928 		return 0;
1929 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1930 		return 0;
1931 	return nfs_compare_mount_options(sb, server, mntflags);
1932 }
1933 
1934 static int nfs_bdi_register(struct nfs_server *server)
1935 {
1936 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
1937 }
1938 
1939 static int nfs_get_sb(struct file_system_type *fs_type,
1940 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1941 {
1942 	struct nfs_server *server = NULL;
1943 	struct super_block *s;
1944 	struct nfs_parsed_mount_data *data;
1945 	struct nfs_fh *mntfh;
1946 	struct dentry *mntroot;
1947 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1948 	struct nfs_sb_mountdata sb_mntdata = {
1949 		.mntflags = flags,
1950 	};
1951 	int error = -ENOMEM;
1952 
1953 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1954 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
1955 	if (data == NULL || mntfh == NULL)
1956 		goto out_free_fh;
1957 
1958 	security_init_mnt_opts(&data->lsm_opts);
1959 
1960 	/* Validate the mount data */
1961 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
1962 	if (error < 0)
1963 		goto out;
1964 
1965 	/* Get a volume representation */
1966 	server = nfs_create_server(data, mntfh);
1967 	if (IS_ERR(server)) {
1968 		error = PTR_ERR(server);
1969 		goto out;
1970 	}
1971 	sb_mntdata.server = server;
1972 
1973 	if (server->flags & NFS_MOUNT_UNSHARED)
1974 		compare_super = NULL;
1975 
1976 	/* Get a superblock - note that we may end up sharing one that already exists */
1977 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1978 	if (IS_ERR(s)) {
1979 		error = PTR_ERR(s);
1980 		goto out_err_nosb;
1981 	}
1982 
1983 	if (s->s_fs_info != server) {
1984 		nfs_free_server(server);
1985 		server = NULL;
1986 	} else {
1987 		error = nfs_bdi_register(server);
1988 		if (error)
1989 			goto error_splat_super;
1990 	}
1991 
1992 	if (!s->s_root) {
1993 		/* initial superblock/root creation */
1994 		nfs_fill_super(s, data);
1995 	}
1996 
1997 	mntroot = nfs_get_root(s, mntfh);
1998 	if (IS_ERR(mntroot)) {
1999 		error = PTR_ERR(mntroot);
2000 		goto error_splat_super;
2001 	}
2002 
2003 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2004 	if (error)
2005 		goto error_splat_root;
2006 
2007 	s->s_flags |= MS_ACTIVE;
2008 	mnt->mnt_sb = s;
2009 	mnt->mnt_root = mntroot;
2010 	error = 0;
2011 
2012 out:
2013 	kfree(data->nfs_server.hostname);
2014 	kfree(data->mount_server.hostname);
2015 	security_free_mnt_opts(&data->lsm_opts);
2016 out_free_fh:
2017 	kfree(mntfh);
2018 	kfree(data);
2019 	return error;
2020 
2021 out_err_nosb:
2022 	nfs_free_server(server);
2023 	goto out;
2024 
2025 error_splat_root:
2026 	dput(mntroot);
2027 error_splat_super:
2028 	up_write(&s->s_umount);
2029 	deactivate_super(s);
2030 	goto out;
2031 }
2032 
2033 /*
2034  * Destroy an NFS2/3 superblock
2035  */
2036 static void nfs_kill_super(struct super_block *s)
2037 {
2038 	struct nfs_server *server = NFS_SB(s);
2039 
2040 	bdi_unregister(&server->backing_dev_info);
2041 	kill_anon_super(s);
2042 	nfs_free_server(server);
2043 }
2044 
2045 /*
2046  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2047  */
2048 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
2049 			   const char *dev_name, void *raw_data,
2050 			   struct vfsmount *mnt)
2051 {
2052 	struct nfs_clone_mount *data = raw_data;
2053 	struct super_block *s;
2054 	struct nfs_server *server;
2055 	struct dentry *mntroot;
2056 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2057 	struct nfs_sb_mountdata sb_mntdata = {
2058 		.mntflags = flags,
2059 	};
2060 	int error;
2061 
2062 	dprintk("--> nfs_xdev_get_sb()\n");
2063 
2064 	/* create a new volume representation */
2065 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2066 	if (IS_ERR(server)) {
2067 		error = PTR_ERR(server);
2068 		goto out_err_noserver;
2069 	}
2070 	sb_mntdata.server = server;
2071 
2072 	if (server->flags & NFS_MOUNT_UNSHARED)
2073 		compare_super = NULL;
2074 
2075 	/* Get a superblock - note that we may end up sharing one that already exists */
2076 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2077 	if (IS_ERR(s)) {
2078 		error = PTR_ERR(s);
2079 		goto out_err_nosb;
2080 	}
2081 
2082 	if (s->s_fs_info != server) {
2083 		nfs_free_server(server);
2084 		server = NULL;
2085 	} else {
2086 		error = nfs_bdi_register(server);
2087 		if (error)
2088 			goto error_splat_super;
2089 	}
2090 
2091 	if (!s->s_root) {
2092 		/* initial superblock/root creation */
2093 		nfs_clone_super(s, data->sb);
2094 	}
2095 
2096 	mntroot = nfs_get_root(s, data->fh);
2097 	if (IS_ERR(mntroot)) {
2098 		error = PTR_ERR(mntroot);
2099 		goto error_splat_super;
2100 	}
2101 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2102 		dput(mntroot);
2103 		error = -ESTALE;
2104 		goto error_splat_super;
2105 	}
2106 
2107 	s->s_flags |= MS_ACTIVE;
2108 	mnt->mnt_sb = s;
2109 	mnt->mnt_root = mntroot;
2110 
2111 	/* clone any lsm security options from the parent to the new sb */
2112 	security_sb_clone_mnt_opts(data->sb, s);
2113 
2114 	dprintk("<-- nfs_xdev_get_sb() = 0\n");
2115 	return 0;
2116 
2117 out_err_nosb:
2118 	nfs_free_server(server);
2119 out_err_noserver:
2120 	dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
2121 	return error;
2122 
2123 error_splat_super:
2124 	up_write(&s->s_umount);
2125 	deactivate_super(s);
2126 	dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
2127 	return error;
2128 }
2129 
2130 #ifdef CONFIG_NFS_V4
2131 
2132 /*
2133  * Finish setting up a cloned NFS4 superblock
2134  */
2135 static void nfs4_clone_super(struct super_block *sb,
2136 			    const struct super_block *old_sb)
2137 {
2138 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2139 	sb->s_blocksize = old_sb->s_blocksize;
2140 	sb->s_maxbytes = old_sb->s_maxbytes;
2141 	sb->s_time_gran = 1;
2142 	sb->s_op = old_sb->s_op;
2143  	nfs_initialise_sb(sb);
2144 }
2145 
2146 /*
2147  * Set up an NFS4 superblock
2148  */
2149 static void nfs4_fill_super(struct super_block *sb)
2150 {
2151 	sb->s_time_gran = 1;
2152 	sb->s_op = &nfs4_sops;
2153 	nfs_initialise_sb(sb);
2154 }
2155 
2156 /*
2157  * Validate NFSv4 mount options
2158  */
2159 static int nfs4_validate_mount_data(void *options,
2160 				    struct nfs_parsed_mount_data *args,
2161 				    const char *dev_name)
2162 {
2163 	struct sockaddr_in *ap;
2164 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2165 	char *c;
2166 
2167 	if (data == NULL)
2168 		goto out_no_data;
2169 
2170 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
2171 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
2172 	args->acregmin		= NFS_DEF_ACREGMIN;
2173 	args->acregmax		= NFS_DEF_ACREGMAX;
2174 	args->acdirmin		= NFS_DEF_ACDIRMIN;
2175 	args->acdirmax		= NFS_DEF_ACDIRMAX;
2176 	args->nfs_server.port	= NFS_PORT; /* 2049 unless user set port= */
2177 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
2178 	args->auth_flavor_len	= 0;
2179 
2180 	switch (data->version) {
2181 	case 1:
2182 		ap = (struct sockaddr_in *)&args->nfs_server.address;
2183 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2184 			goto out_no_address;
2185 		if (data->host_addrlen == 0)
2186 			goto out_no_address;
2187 		args->nfs_server.addrlen = data->host_addrlen;
2188 		if (copy_from_user(ap, data->host_addr, data->host_addrlen))
2189 			return -EFAULT;
2190 		if (!nfs_verify_server_address((struct sockaddr *)
2191 						&args->nfs_server.address))
2192 			goto out_no_address;
2193 
2194 		if (data->auth_flavourlen) {
2195 			if (data->auth_flavourlen > 1)
2196 				goto out_inval_auth;
2197 			if (copy_from_user(&args->auth_flavors[0],
2198 					   data->auth_flavours,
2199 					   sizeof(args->auth_flavors[0])))
2200 				return -EFAULT;
2201 		}
2202 
2203 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2204 		if (IS_ERR(c))
2205 			return PTR_ERR(c);
2206 		args->nfs_server.hostname = c;
2207 
2208 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2209 		if (IS_ERR(c))
2210 			return PTR_ERR(c);
2211 		args->nfs_server.export_path = c;
2212 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2213 
2214 		c = strndup_user(data->client_addr.data, 16);
2215 		if (IS_ERR(c))
2216 			return PTR_ERR(c);
2217 		args->client_address = c;
2218 
2219 		/*
2220 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2221 		 * can deal with.
2222 		 */
2223 
2224 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2225 		args->rsize	= data->rsize;
2226 		args->wsize	= data->wsize;
2227 		args->timeo	= data->timeo;
2228 		args->retrans	= data->retrans;
2229 		args->acregmin	= data->acregmin;
2230 		args->acregmax	= data->acregmax;
2231 		args->acdirmin	= data->acdirmin;
2232 		args->acdirmax	= data->acdirmax;
2233 		args->nfs_server.protocol = data->proto;
2234 		nfs_validate_transport_protocol(args);
2235 
2236 		break;
2237 	default: {
2238 		int status;
2239 
2240 		if (nfs_parse_mount_options((char *)options, args) == 0)
2241 			return -EINVAL;
2242 
2243 		if (!nfs_verify_server_address((struct sockaddr *)
2244 						&args->nfs_server.address))
2245 			return -EINVAL;
2246 
2247 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
2248 				args->nfs_server.port);
2249 
2250 		nfs_validate_transport_protocol(args);
2251 
2252 		if (args->auth_flavor_len > 1)
2253 			goto out_inval_auth;
2254 
2255 		if (args->client_address == NULL)
2256 			goto out_no_client_address;
2257 
2258 		status = nfs_parse_devname(dev_name,
2259 					   &args->nfs_server.hostname,
2260 					   NFS4_MAXNAMLEN,
2261 					   &args->nfs_server.export_path,
2262 					   NFS4_MAXPATHLEN);
2263 		if (status < 0)
2264 			return status;
2265 
2266 		break;
2267 		}
2268 	}
2269 
2270 	return 0;
2271 
2272 out_no_data:
2273 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2274 	return -EINVAL;
2275 
2276 out_inval_auth:
2277 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2278 		 data->auth_flavourlen);
2279 	return -EINVAL;
2280 
2281 out_no_address:
2282 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2283 	return -EINVAL;
2284 
2285 out_no_client_address:
2286 	dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
2287 	return -EINVAL;
2288 }
2289 
2290 /*
2291  * Get the superblock for an NFS4 mountpoint
2292  */
2293 static int nfs4_get_sb(struct file_system_type *fs_type,
2294 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2295 {
2296 	struct nfs_parsed_mount_data *data;
2297 	struct super_block *s;
2298 	struct nfs_server *server;
2299 	struct nfs_fh *mntfh;
2300 	struct dentry *mntroot;
2301 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2302 	struct nfs_sb_mountdata sb_mntdata = {
2303 		.mntflags = flags,
2304 	};
2305 	int error = -ENOMEM;
2306 
2307 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2308 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
2309 	if (data == NULL || mntfh == NULL)
2310 		goto out_free_fh;
2311 
2312 	security_init_mnt_opts(&data->lsm_opts);
2313 
2314 	/* Validate the mount data */
2315 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2316 	if (error < 0)
2317 		goto out;
2318 
2319 	/* Get a volume representation */
2320 	server = nfs4_create_server(data, mntfh);
2321 	if (IS_ERR(server)) {
2322 		error = PTR_ERR(server);
2323 		goto out;
2324 	}
2325 	sb_mntdata.server = server;
2326 
2327 	if (server->flags & NFS4_MOUNT_UNSHARED)
2328 		compare_super = NULL;
2329 
2330 	/* Get a superblock - note that we may end up sharing one that already exists */
2331 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2332 	if (IS_ERR(s)) {
2333 		error = PTR_ERR(s);
2334 		goto out_free;
2335 	}
2336 
2337 	if (s->s_fs_info != server) {
2338 		nfs_free_server(server);
2339 		server = NULL;
2340 	} else {
2341 		error = nfs_bdi_register(server);
2342 		if (error)
2343 			goto error_splat_super;
2344 	}
2345 
2346 	if (!s->s_root) {
2347 		/* initial superblock/root creation */
2348 		nfs4_fill_super(s);
2349 	}
2350 
2351 	mntroot = nfs4_get_root(s, mntfh);
2352 	if (IS_ERR(mntroot)) {
2353 		error = PTR_ERR(mntroot);
2354 		goto error_splat_super;
2355 	}
2356 
2357 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2358 	if (error)
2359 		goto error_splat_root;
2360 
2361 	s->s_flags |= MS_ACTIVE;
2362 	mnt->mnt_sb = s;
2363 	mnt->mnt_root = mntroot;
2364 	error = 0;
2365 
2366 out:
2367 	kfree(data->client_address);
2368 	kfree(data->nfs_server.export_path);
2369 	kfree(data->nfs_server.hostname);
2370 	security_free_mnt_opts(&data->lsm_opts);
2371 out_free_fh:
2372 	kfree(mntfh);
2373 	kfree(data);
2374 	return error;
2375 
2376 out_free:
2377 	nfs_free_server(server);
2378 	goto out;
2379 
2380 error_splat_root:
2381 	dput(mntroot);
2382 error_splat_super:
2383 	up_write(&s->s_umount);
2384 	deactivate_super(s);
2385 	goto out;
2386 }
2387 
2388 static void nfs4_kill_super(struct super_block *sb)
2389 {
2390 	struct nfs_server *server = NFS_SB(sb);
2391 
2392 	nfs_return_all_delegations(sb);
2393 	kill_anon_super(sb);
2394 
2395 	nfs4_renewd_prepare_shutdown(server);
2396 	nfs_free_server(server);
2397 }
2398 
2399 /*
2400  * Clone an NFS4 server record on xdev traversal (FSID-change)
2401  */
2402 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
2403 			    const char *dev_name, void *raw_data,
2404 			    struct vfsmount *mnt)
2405 {
2406 	struct nfs_clone_mount *data = raw_data;
2407 	struct super_block *s;
2408 	struct nfs_server *server;
2409 	struct dentry *mntroot;
2410 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2411 	struct nfs_sb_mountdata sb_mntdata = {
2412 		.mntflags = flags,
2413 	};
2414 	int error;
2415 
2416 	dprintk("--> nfs4_xdev_get_sb()\n");
2417 
2418 	/* create a new volume representation */
2419 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2420 	if (IS_ERR(server)) {
2421 		error = PTR_ERR(server);
2422 		goto out_err_noserver;
2423 	}
2424 	sb_mntdata.server = server;
2425 
2426 	if (server->flags & NFS4_MOUNT_UNSHARED)
2427 		compare_super = NULL;
2428 
2429 	/* Get a superblock - note that we may end up sharing one that already exists */
2430 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2431 	if (IS_ERR(s)) {
2432 		error = PTR_ERR(s);
2433 		goto out_err_nosb;
2434 	}
2435 
2436 	if (s->s_fs_info != server) {
2437 		nfs_free_server(server);
2438 		server = NULL;
2439 	} else {
2440 		error = nfs_bdi_register(server);
2441 		if (error)
2442 			goto error_splat_super;
2443 	}
2444 
2445 	if (!s->s_root) {
2446 		/* initial superblock/root creation */
2447 		nfs4_clone_super(s, data->sb);
2448 	}
2449 
2450 	mntroot = nfs4_get_root(s, data->fh);
2451 	if (IS_ERR(mntroot)) {
2452 		error = PTR_ERR(mntroot);
2453 		goto error_splat_super;
2454 	}
2455 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2456 		dput(mntroot);
2457 		error = -ESTALE;
2458 		goto error_splat_super;
2459 	}
2460 
2461 	s->s_flags |= MS_ACTIVE;
2462 	mnt->mnt_sb = s;
2463 	mnt->mnt_root = mntroot;
2464 
2465 	security_sb_clone_mnt_opts(data->sb, s);
2466 
2467 	dprintk("<-- nfs4_xdev_get_sb() = 0\n");
2468 	return 0;
2469 
2470 out_err_nosb:
2471 	nfs_free_server(server);
2472 out_err_noserver:
2473 	dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
2474 	return error;
2475 
2476 error_splat_super:
2477 	up_write(&s->s_umount);
2478 	deactivate_super(s);
2479 	dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
2480 	return error;
2481 }
2482 
2483 /*
2484  * Create an NFS4 server record on referral traversal
2485  */
2486 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
2487 				const char *dev_name, void *raw_data,
2488 				struct vfsmount *mnt)
2489 {
2490 	struct nfs_clone_mount *data = raw_data;
2491 	struct super_block *s;
2492 	struct nfs_server *server;
2493 	struct dentry *mntroot;
2494 	struct nfs_fh mntfh;
2495 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2496 	struct nfs_sb_mountdata sb_mntdata = {
2497 		.mntflags = flags,
2498 	};
2499 	int error;
2500 
2501 	dprintk("--> nfs4_referral_get_sb()\n");
2502 
2503 	/* create a new volume representation */
2504 	server = nfs4_create_referral_server(data, &mntfh);
2505 	if (IS_ERR(server)) {
2506 		error = PTR_ERR(server);
2507 		goto out_err_noserver;
2508 	}
2509 	sb_mntdata.server = server;
2510 
2511 	if (server->flags & NFS4_MOUNT_UNSHARED)
2512 		compare_super = NULL;
2513 
2514 	/* Get a superblock - note that we may end up sharing one that already exists */
2515 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2516 	if (IS_ERR(s)) {
2517 		error = PTR_ERR(s);
2518 		goto out_err_nosb;
2519 	}
2520 
2521 	if (s->s_fs_info != server) {
2522 		nfs_free_server(server);
2523 		server = NULL;
2524 	} else {
2525 		error = nfs_bdi_register(server);
2526 		if (error)
2527 			goto error_splat_super;
2528 	}
2529 
2530 	if (!s->s_root) {
2531 		/* initial superblock/root creation */
2532 		nfs4_fill_super(s);
2533 	}
2534 
2535 	mntroot = nfs4_get_root(s, &mntfh);
2536 	if (IS_ERR(mntroot)) {
2537 		error = PTR_ERR(mntroot);
2538 		goto error_splat_super;
2539 	}
2540 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2541 		dput(mntroot);
2542 		error = -ESTALE;
2543 		goto error_splat_super;
2544 	}
2545 
2546 	s->s_flags |= MS_ACTIVE;
2547 	mnt->mnt_sb = s;
2548 	mnt->mnt_root = mntroot;
2549 
2550 	security_sb_clone_mnt_opts(data->sb, s);
2551 
2552 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
2553 	return 0;
2554 
2555 out_err_nosb:
2556 	nfs_free_server(server);
2557 out_err_noserver:
2558 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
2559 	return error;
2560 
2561 error_splat_super:
2562 	up_write(&s->s_umount);
2563 	deactivate_super(s);
2564 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
2565 	return error;
2566 }
2567 
2568 #endif /* CONFIG_NFS_V4 */
2569