xref: /linux/fs/nfs/super.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
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/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 	Opt_lookupcache,
95 
96 	/* Special mount options */
97 	Opt_userspace, Opt_deprecated, Opt_sloppy,
98 
99 	Opt_err
100 };
101 
102 static const match_table_t nfs_mount_option_tokens = {
103 	{ Opt_userspace, "bg" },
104 	{ Opt_userspace, "fg" },
105 	{ Opt_userspace, "retry=%s" },
106 
107 	{ Opt_sloppy, "sloppy" },
108 
109 	{ Opt_soft, "soft" },
110 	{ Opt_hard, "hard" },
111 	{ Opt_deprecated, "intr" },
112 	{ Opt_deprecated, "nointr" },
113 	{ Opt_posix, "posix" },
114 	{ Opt_noposix, "noposix" },
115 	{ Opt_cto, "cto" },
116 	{ Opt_nocto, "nocto" },
117 	{ Opt_ac, "ac" },
118 	{ Opt_noac, "noac" },
119 	{ Opt_lock, "lock" },
120 	{ Opt_nolock, "nolock" },
121 	{ Opt_v2, "v2" },
122 	{ Opt_v3, "v3" },
123 	{ Opt_udp, "udp" },
124 	{ Opt_tcp, "tcp" },
125 	{ Opt_rdma, "rdma" },
126 	{ Opt_acl, "acl" },
127 	{ Opt_noacl, "noacl" },
128 	{ Opt_rdirplus, "rdirplus" },
129 	{ Opt_nordirplus, "nordirplus" },
130 	{ Opt_sharecache, "sharecache" },
131 	{ Opt_nosharecache, "nosharecache" },
132 
133 	{ Opt_port, "port=%u" },
134 	{ Opt_rsize, "rsize=%u" },
135 	{ Opt_wsize, "wsize=%u" },
136 	{ Opt_bsize, "bsize=%u" },
137 	{ Opt_timeo, "timeo=%u" },
138 	{ Opt_retrans, "retrans=%u" },
139 	{ Opt_acregmin, "acregmin=%u" },
140 	{ Opt_acregmax, "acregmax=%u" },
141 	{ Opt_acdirmin, "acdirmin=%u" },
142 	{ Opt_acdirmax, "acdirmax=%u" },
143 	{ Opt_actimeo, "actimeo=%u" },
144 	{ Opt_namelen, "namlen=%u" },
145 	{ Opt_mountport, "mountport=%u" },
146 	{ Opt_mountvers, "mountvers=%u" },
147 	{ Opt_nfsvers, "nfsvers=%u" },
148 	{ Opt_nfsvers, "vers=%u" },
149 
150 	{ Opt_sec, "sec=%s" },
151 	{ Opt_proto, "proto=%s" },
152 	{ Opt_mountproto, "mountproto=%s" },
153 	{ Opt_addr, "addr=%s" },
154 	{ Opt_clientaddr, "clientaddr=%s" },
155 	{ Opt_mounthost, "mounthost=%s" },
156 	{ Opt_mountaddr, "mountaddr=%s" },
157 
158 	{ Opt_lookupcache, "lookupcache=%s" },
159 
160 	{ Opt_err, NULL }
161 };
162 
163 enum {
164 	Opt_xprt_udp, Opt_xprt_tcp, Opt_xprt_rdma,
165 
166 	Opt_xprt_err
167 };
168 
169 static const match_table_t nfs_xprt_protocol_tokens = {
170 	{ Opt_xprt_udp, "udp" },
171 	{ Opt_xprt_tcp, "tcp" },
172 	{ Opt_xprt_rdma, "rdma" },
173 
174 	{ Opt_xprt_err, NULL }
175 };
176 
177 enum {
178 	Opt_sec_none, Opt_sec_sys,
179 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
180 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
181 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
182 
183 	Opt_sec_err
184 };
185 
186 static const match_table_t nfs_secflavor_tokens = {
187 	{ Opt_sec_none, "none" },
188 	{ Opt_sec_none, "null" },
189 	{ Opt_sec_sys, "sys" },
190 
191 	{ Opt_sec_krb5, "krb5" },
192 	{ Opt_sec_krb5i, "krb5i" },
193 	{ Opt_sec_krb5p, "krb5p" },
194 
195 	{ Opt_sec_lkey, "lkey" },
196 	{ Opt_sec_lkeyi, "lkeyi" },
197 	{ Opt_sec_lkeyp, "lkeyp" },
198 
199 	{ Opt_sec_spkm, "spkm3" },
200 	{ Opt_sec_spkmi, "spkm3i" },
201 	{ Opt_sec_spkmp, "spkm3p" },
202 
203 	{ Opt_sec_err, NULL }
204 };
205 
206 enum {
207 	Opt_lookupcache_all, Opt_lookupcache_positive,
208 	Opt_lookupcache_none,
209 
210 	Opt_lookupcache_err
211 };
212 
213 static match_table_t nfs_lookupcache_tokens = {
214 	{ Opt_lookupcache_all, "all" },
215 	{ Opt_lookupcache_positive, "pos" },
216 	{ Opt_lookupcache_positive, "positive" },
217 	{ Opt_lookupcache_none, "none" },
218 
219 	{ Opt_lookupcache_err, NULL }
220 };
221 
222 
223 static void nfs_umount_begin(struct super_block *);
224 static int  nfs_statfs(struct dentry *, struct kstatfs *);
225 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
226 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
227 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
228 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
229 		int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
230 static void nfs_kill_super(struct super_block *);
231 static int nfs_remount(struct super_block *sb, int *flags, char *raw_data);
232 
233 static struct file_system_type nfs_fs_type = {
234 	.owner		= THIS_MODULE,
235 	.name		= "nfs",
236 	.get_sb		= nfs_get_sb,
237 	.kill_sb	= nfs_kill_super,
238 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
239 };
240 
241 struct file_system_type nfs_xdev_fs_type = {
242 	.owner		= THIS_MODULE,
243 	.name		= "nfs",
244 	.get_sb		= nfs_xdev_get_sb,
245 	.kill_sb	= nfs_kill_super,
246 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
247 };
248 
249 static const struct super_operations nfs_sops = {
250 	.alloc_inode	= nfs_alloc_inode,
251 	.destroy_inode	= nfs_destroy_inode,
252 	.write_inode	= nfs_write_inode,
253 	.statfs		= nfs_statfs,
254 	.clear_inode	= nfs_clear_inode,
255 	.umount_begin	= nfs_umount_begin,
256 	.show_options	= nfs_show_options,
257 	.show_stats	= nfs_show_stats,
258 	.remount_fs	= nfs_remount,
259 };
260 
261 #ifdef CONFIG_NFS_V4
262 static int nfs4_get_sb(struct file_system_type *fs_type,
263 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
264 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
265 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
266 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
267 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
268 static void nfs4_kill_super(struct super_block *sb);
269 
270 static struct file_system_type nfs4_fs_type = {
271 	.owner		= THIS_MODULE,
272 	.name		= "nfs4",
273 	.get_sb		= nfs4_get_sb,
274 	.kill_sb	= nfs4_kill_super,
275 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
276 };
277 
278 struct file_system_type nfs4_xdev_fs_type = {
279 	.owner		= THIS_MODULE,
280 	.name		= "nfs4",
281 	.get_sb		= nfs4_xdev_get_sb,
282 	.kill_sb	= nfs4_kill_super,
283 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
284 };
285 
286 struct file_system_type nfs4_referral_fs_type = {
287 	.owner		= THIS_MODULE,
288 	.name		= "nfs4",
289 	.get_sb		= nfs4_referral_get_sb,
290 	.kill_sb	= nfs4_kill_super,
291 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
292 };
293 
294 static const struct super_operations nfs4_sops = {
295 	.alloc_inode	= nfs_alloc_inode,
296 	.destroy_inode	= nfs_destroy_inode,
297 	.write_inode	= nfs_write_inode,
298 	.statfs		= nfs_statfs,
299 	.clear_inode	= nfs4_clear_inode,
300 	.umount_begin	= nfs_umount_begin,
301 	.show_options	= nfs_show_options,
302 	.show_stats	= nfs_show_stats,
303 	.remount_fs	= nfs_remount,
304 };
305 #endif
306 
307 static struct shrinker acl_shrinker = {
308 	.shrink		= nfs_access_cache_shrinker,
309 	.seeks		= DEFAULT_SEEKS,
310 };
311 
312 /*
313  * Register the NFS filesystems
314  */
315 int __init register_nfs_fs(void)
316 {
317 	int ret;
318 
319         ret = register_filesystem(&nfs_fs_type);
320 	if (ret < 0)
321 		goto error_0;
322 
323 	ret = nfs_register_sysctl();
324 	if (ret < 0)
325 		goto error_1;
326 #ifdef CONFIG_NFS_V4
327 	ret = register_filesystem(&nfs4_fs_type);
328 	if (ret < 0)
329 		goto error_2;
330 #endif
331 	register_shrinker(&acl_shrinker);
332 	return 0;
333 
334 #ifdef CONFIG_NFS_V4
335 error_2:
336 	nfs_unregister_sysctl();
337 #endif
338 error_1:
339 	unregister_filesystem(&nfs_fs_type);
340 error_0:
341 	return ret;
342 }
343 
344 /*
345  * Unregister the NFS filesystems
346  */
347 void __exit unregister_nfs_fs(void)
348 {
349 	unregister_shrinker(&acl_shrinker);
350 #ifdef CONFIG_NFS_V4
351 	unregister_filesystem(&nfs4_fs_type);
352 #endif
353 	nfs_unregister_sysctl();
354 	unregister_filesystem(&nfs_fs_type);
355 }
356 
357 void nfs_sb_active(struct super_block *sb)
358 {
359 	struct nfs_server *server = NFS_SB(sb);
360 
361 	if (atomic_inc_return(&server->active) == 1)
362 		atomic_inc(&sb->s_active);
363 }
364 
365 void nfs_sb_deactive(struct super_block *sb)
366 {
367 	struct nfs_server *server = NFS_SB(sb);
368 
369 	if (atomic_dec_and_test(&server->active))
370 		deactivate_super(sb);
371 }
372 
373 /*
374  * Deliver file system statistics to userspace
375  */
376 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
377 {
378 	struct nfs_server *server = NFS_SB(dentry->d_sb);
379 	unsigned char blockbits;
380 	unsigned long blockres;
381 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
382 	struct nfs_fattr fattr;
383 	struct nfs_fsstat res = {
384 			.fattr = &fattr,
385 	};
386 	int error;
387 
388 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
389 	if (error < 0)
390 		goto out_err;
391 	buf->f_type = NFS_SUPER_MAGIC;
392 
393 	/*
394 	 * Current versions of glibc do not correctly handle the
395 	 * case where f_frsize != f_bsize.  Eventually we want to
396 	 * report the value of wtmult in this field.
397 	 */
398 	buf->f_frsize = dentry->d_sb->s_blocksize;
399 
400 	/*
401 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
402 	 * are reported in units of f_frsize.  Linux hasn't had
403 	 * an f_frsize field in its statfs struct until recently,
404 	 * thus historically Linux's sys_statfs reports these
405 	 * fields in units of f_bsize.
406 	 */
407 	buf->f_bsize = dentry->d_sb->s_blocksize;
408 	blockbits = dentry->d_sb->s_blocksize_bits;
409 	blockres = (1 << blockbits) - 1;
410 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
411 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
412 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
413 
414 	buf->f_files = res.tfiles;
415 	buf->f_ffree = res.afiles;
416 
417 	buf->f_namelen = server->namelen;
418 
419 	return 0;
420 
421  out_err:
422 	dprintk("%s: statfs error = %d\n", __func__, -error);
423 	return error;
424 }
425 
426 /*
427  * Map the security flavour number to a name
428  */
429 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
430 {
431 	static const struct {
432 		rpc_authflavor_t flavour;
433 		const char *str;
434 	} sec_flavours[] = {
435 		{ RPC_AUTH_NULL, "null" },
436 		{ RPC_AUTH_UNIX, "sys" },
437 		{ RPC_AUTH_GSS_KRB5, "krb5" },
438 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
439 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
440 		{ RPC_AUTH_GSS_LKEY, "lkey" },
441 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
442 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
443 		{ RPC_AUTH_GSS_SPKM, "spkm" },
444 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
445 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
446 		{ UINT_MAX, "unknown" }
447 	};
448 	int i;
449 
450 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
451 		if (sec_flavours[i].flavour == flavour)
452 			break;
453 	}
454 	return sec_flavours[i].str;
455 }
456 
457 static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
458 				    int showdefaults)
459 {
460 	struct sockaddr *sap = (struct sockaddr *)&nfss->mountd_address;
461 
462 	switch (sap->sa_family) {
463 	case AF_INET: {
464 		struct sockaddr_in *sin = (struct sockaddr_in *)sap;
465 		seq_printf(m, ",mountaddr=" NIPQUAD_FMT,
466 				NIPQUAD(sin->sin_addr.s_addr));
467 		break;
468 	}
469 	case AF_INET6: {
470 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
471 		seq_printf(m, ",mountaddr=" NIP6_FMT,
472 				NIP6(sin6->sin6_addr));
473 		break;
474 	}
475 	default:
476 		if (showdefaults)
477 			seq_printf(m, ",mountaddr=unspecified");
478 	}
479 
480 	if (nfss->mountd_version || showdefaults)
481 		seq_printf(m, ",mountvers=%u", nfss->mountd_version);
482 	if (nfss->mountd_port || showdefaults)
483 		seq_printf(m, ",mountport=%u", nfss->mountd_port);
484 
485 	switch (nfss->mountd_protocol) {
486 	case IPPROTO_UDP:
487 		seq_printf(m, ",mountproto=udp");
488 		break;
489 	case IPPROTO_TCP:
490 		seq_printf(m, ",mountproto=tcp");
491 		break;
492 	default:
493 		if (showdefaults)
494 			seq_printf(m, ",mountproto=auto");
495 	}
496 }
497 
498 /*
499  * Describe the mount options in force on this server representation
500  */
501 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
502 				   int showdefaults)
503 {
504 	static const struct proc_nfs_info {
505 		int flag;
506 		const char *str;
507 		const char *nostr;
508 	} nfs_info[] = {
509 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
510 		{ NFS_MOUNT_INTR, ",intr", ",nointr" },
511 		{ NFS_MOUNT_POSIX, ",posix", "" },
512 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
513 		{ NFS_MOUNT_NOAC, ",noac", "" },
514 		{ NFS_MOUNT_NONLM, ",nolock", "" },
515 		{ NFS_MOUNT_NOACL, ",noacl", "" },
516 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
517 		{ NFS_MOUNT_UNSHARED, ",nosharecache", ""},
518 		{ 0, NULL, NULL }
519 	};
520 	const struct proc_nfs_info *nfs_infop;
521 	struct nfs_client *clp = nfss->nfs_client;
522 	u32 version = clp->rpc_ops->version;
523 
524 	seq_printf(m, ",vers=%u", version);
525 	seq_printf(m, ",rsize=%u", nfss->rsize);
526 	seq_printf(m, ",wsize=%u", nfss->wsize);
527 	if (nfss->bsize != 0)
528 		seq_printf(m, ",bsize=%u", nfss->bsize);
529 	seq_printf(m, ",namlen=%u", nfss->namelen);
530 	if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
531 		seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
532 	if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
533 		seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
534 	if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
535 		seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
536 	if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
537 		seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
538 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
539 		if (nfss->flags & nfs_infop->flag)
540 			seq_puts(m, nfs_infop->str);
541 		else
542 			seq_puts(m, nfs_infop->nostr);
543 	}
544 	seq_printf(m, ",proto=%s",
545 		   rpc_peeraddr2str(nfss->client, RPC_DISPLAY_PROTO));
546 	if (version == 4) {
547 		if (nfss->port != NFS_PORT)
548 			seq_printf(m, ",port=%u", nfss->port);
549 	} else
550 		if (nfss->port)
551 			seq_printf(m, ",port=%u", nfss->port);
552 
553 	seq_printf(m, ",timeo=%lu", 10U * nfss->client->cl_timeout->to_initval / HZ);
554 	seq_printf(m, ",retrans=%u", nfss->client->cl_timeout->to_retries);
555 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
556 
557 	if (version != 4)
558 		nfs_show_mountd_options(m, nfss, showdefaults);
559 
560 #ifdef CONFIG_NFS_V4
561 	if (clp->rpc_ops->version == 4)
562 		seq_printf(m, ",clientaddr=%s", clp->cl_ipaddr);
563 #endif
564 }
565 
566 /*
567  * Describe the mount options on this VFS mountpoint
568  */
569 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
570 {
571 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
572 
573 	nfs_show_mount_options(m, nfss, 0);
574 
575 	seq_printf(m, ",addr=%s",
576 			rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
577 							RPC_DISPLAY_ADDR));
578 
579 	return 0;
580 }
581 
582 /*
583  * Present statistical information for this VFS mountpoint
584  */
585 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
586 {
587 	int i, cpu;
588 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
589 	struct rpc_auth *auth = nfss->client->cl_auth;
590 	struct nfs_iostats totals = { };
591 
592 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
593 
594 	/*
595 	 * Display all mount option settings
596 	 */
597 	seq_printf(m, "\n\topts:\t");
598 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
599 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
600 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
601 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
602 	nfs_show_mount_options(m, nfss, 1);
603 
604 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
605 
606 	seq_printf(m, "\n\tcaps:\t");
607 	seq_printf(m, "caps=0x%x", nfss->caps);
608 	seq_printf(m, ",wtmult=%u", nfss->wtmult);
609 	seq_printf(m, ",dtsize=%u", nfss->dtsize);
610 	seq_printf(m, ",bsize=%u", nfss->bsize);
611 	seq_printf(m, ",namlen=%u", nfss->namelen);
612 
613 #ifdef CONFIG_NFS_V4
614 	if (nfss->nfs_client->rpc_ops->version == 4) {
615 		seq_printf(m, "\n\tnfsv4:\t");
616 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
617 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
618 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
619 	}
620 #endif
621 
622 	/*
623 	 * Display security flavor in effect for this mount
624 	 */
625 	seq_printf(m, "\n\tsec:\tflavor=%u", auth->au_ops->au_flavor);
626 	if (auth->au_flavor)
627 		seq_printf(m, ",pseudoflavor=%u", auth->au_flavor);
628 
629 	/*
630 	 * Display superblock I/O counters
631 	 */
632 	for_each_possible_cpu(cpu) {
633 		struct nfs_iostats *stats;
634 
635 		preempt_disable();
636 		stats = per_cpu_ptr(nfss->io_stats, cpu);
637 
638 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
639 			totals.events[i] += stats->events[i];
640 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
641 			totals.bytes[i] += stats->bytes[i];
642 
643 		preempt_enable();
644 	}
645 
646 	seq_printf(m, "\n\tevents:\t");
647 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
648 		seq_printf(m, "%lu ", totals.events[i]);
649 	seq_printf(m, "\n\tbytes:\t");
650 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
651 		seq_printf(m, "%Lu ", totals.bytes[i]);
652 	seq_printf(m, "\n");
653 
654 	rpc_print_iostats(m, nfss->client);
655 
656 	return 0;
657 }
658 
659 /*
660  * Begin unmount by attempting to remove all automounted mountpoints we added
661  * in response to xdev traversals and referrals
662  */
663 static void nfs_umount_begin(struct super_block *sb)
664 {
665 	struct nfs_server *server = NFS_SB(sb);
666 	struct rpc_clnt *rpc;
667 
668 	/* -EIO all pending I/O */
669 	rpc = server->client_acl;
670 	if (!IS_ERR(rpc))
671 		rpc_killall_tasks(rpc);
672 	rpc = server->client;
673 	if (!IS_ERR(rpc))
674 		rpc_killall_tasks(rpc);
675 }
676 
677 /*
678  * Sanity-check a server address provided by the mount command.
679  *
680  * Address family must be initialized, and address must not be
681  * the ANY address for that family.
682  */
683 static int nfs_verify_server_address(struct sockaddr *addr)
684 {
685 	switch (addr->sa_family) {
686 	case AF_INET: {
687 		struct sockaddr_in *sa = (struct sockaddr_in *)addr;
688 		return sa->sin_addr.s_addr != htonl(INADDR_ANY);
689 	}
690 	case AF_INET6: {
691 		struct in6_addr *sa = &((struct sockaddr_in6 *)addr)->sin6_addr;
692 		return !ipv6_addr_any(sa);
693 	}
694 	}
695 
696 	return 0;
697 }
698 
699 static void nfs_parse_ipv4_address(char *string, size_t str_len,
700 				   struct sockaddr *sap, size_t *addr_len)
701 {
702 	struct sockaddr_in *sin = (struct sockaddr_in *)sap;
703 	u8 *addr = (u8 *)&sin->sin_addr.s_addr;
704 
705 	if (str_len <= INET_ADDRSTRLEN) {
706 		dfprintk(MOUNT, "NFS: parsing IPv4 address %*s\n",
707 				(int)str_len, string);
708 
709 		sin->sin_family = AF_INET;
710 		*addr_len = sizeof(*sin);
711 		if (in4_pton(string, str_len, addr, '\0', NULL))
712 			return;
713 	}
714 
715 	sap->sa_family = AF_UNSPEC;
716 	*addr_len = 0;
717 }
718 
719 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
720 static int nfs_parse_ipv6_scope_id(const char *string, const size_t str_len,
721 				   const char *delim,
722 				   struct sockaddr_in6 *sin6)
723 {
724 	char *p;
725 	size_t len;
726 
727 	if ((string + str_len) == delim)
728 		return 1;
729 
730 	if (*delim != IPV6_SCOPE_DELIMITER)
731 		return 0;
732 
733 	if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
734 		return 0;
735 
736 	len = (string + str_len) - delim - 1;
737 	p = kstrndup(delim + 1, len, GFP_KERNEL);
738 	if (p) {
739 		unsigned long scope_id = 0;
740 		struct net_device *dev;
741 
742 		dev = dev_get_by_name(&init_net, p);
743 		if (dev != NULL) {
744 			scope_id = dev->ifindex;
745 			dev_put(dev);
746 		} else {
747 			if (strict_strtoul(p, 10, &scope_id) == 0) {
748 				kfree(p);
749 				return 0;
750 			}
751 		}
752 
753 		kfree(p);
754 
755 		sin6->sin6_scope_id = scope_id;
756 		dfprintk(MOUNT, "NFS: IPv6 scope ID = %lu\n", scope_id);
757 		return 1;
758 	}
759 
760 	return 0;
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,
777 					IPV6_SCOPE_DELIMITER, &delim) != 0) {
778 			if (nfs_parse_ipv6_scope_id(string, str_len,
779 							delim, sin6) != 0)
780 				return;
781 		}
782 	}
783 
784 	sap->sa_family = AF_UNSPEC;
785 	*addr_len = 0;
786 }
787 #else
788 static void nfs_parse_ipv6_address(char *string, size_t str_len,
789 				   struct sockaddr *sap, size_t *addr_len)
790 {
791 	sap->sa_family = AF_UNSPEC;
792 	*addr_len = 0;
793 }
794 #endif
795 
796 /*
797  * Construct a sockaddr based on the contents of a string that contains
798  * an IP address in presentation format.
799  *
800  * If there is a problem constructing the new sockaddr, set the address
801  * family to AF_UNSPEC.
802  */
803 void nfs_parse_ip_address(char *string, size_t str_len,
804 				 struct sockaddr *sap, size_t *addr_len)
805 {
806 	unsigned int i, colons;
807 
808 	colons = 0;
809 	for (i = 0; i < str_len; i++)
810 		if (string[i] == ':')
811 			colons++;
812 
813 	if (colons >= 2)
814 		nfs_parse_ipv6_address(string, str_len, sap, addr_len);
815 	else
816 		nfs_parse_ipv4_address(string, str_len, sap, addr_len);
817 }
818 
819 /*
820  * Sanity check the NFS transport protocol.
821  *
822  */
823 static void nfs_validate_transport_protocol(struct nfs_parsed_mount_data *mnt)
824 {
825 	switch (mnt->nfs_server.protocol) {
826 	case XPRT_TRANSPORT_UDP:
827 	case XPRT_TRANSPORT_TCP:
828 	case XPRT_TRANSPORT_RDMA:
829 		break;
830 	default:
831 		mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
832 	}
833 }
834 
835 /*
836  * For text based NFSv2/v3 mounts, the mount protocol transport default
837  * settings should depend upon the specified NFS transport.
838  */
839 static void nfs_set_mount_transport_protocol(struct nfs_parsed_mount_data *mnt)
840 {
841 	nfs_validate_transport_protocol(mnt);
842 
843 	if (mnt->mount_server.protocol == XPRT_TRANSPORT_UDP ||
844 	    mnt->mount_server.protocol == XPRT_TRANSPORT_TCP)
845 			return;
846 	switch (mnt->nfs_server.protocol) {
847 	case XPRT_TRANSPORT_UDP:
848 		mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
849 		break;
850 	case XPRT_TRANSPORT_TCP:
851 	case XPRT_TRANSPORT_RDMA:
852 		mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
853 	}
854 }
855 
856 /*
857  * Parse the value of the 'sec=' option.
858  *
859  * The flavor_len setting is for v4 mounts.
860  */
861 static int nfs_parse_security_flavors(char *value,
862 				      struct nfs_parsed_mount_data *mnt)
863 {
864 	substring_t args[MAX_OPT_ARGS];
865 
866 	dfprintk(MOUNT, "NFS: parsing sec=%s option\n", value);
867 
868 	switch (match_token(value, nfs_secflavor_tokens, args)) {
869 	case Opt_sec_none:
870 		mnt->auth_flavor_len = 0;
871 		mnt->auth_flavors[0] = RPC_AUTH_NULL;
872 		break;
873 	case Opt_sec_sys:
874 		mnt->auth_flavor_len = 0;
875 		mnt->auth_flavors[0] = RPC_AUTH_UNIX;
876 		break;
877 	case Opt_sec_krb5:
878 		mnt->auth_flavor_len = 1;
879 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
880 		break;
881 	case Opt_sec_krb5i:
882 		mnt->auth_flavor_len = 1;
883 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
884 		break;
885 	case Opt_sec_krb5p:
886 		mnt->auth_flavor_len = 1;
887 		mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
888 		break;
889 	case Opt_sec_lkey:
890 		mnt->auth_flavor_len = 1;
891 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
892 		break;
893 	case Opt_sec_lkeyi:
894 		mnt->auth_flavor_len = 1;
895 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
896 		break;
897 	case Opt_sec_lkeyp:
898 		mnt->auth_flavor_len = 1;
899 		mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
900 		break;
901 	case Opt_sec_spkm:
902 		mnt->auth_flavor_len = 1;
903 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
904 		break;
905 	case Opt_sec_spkmi:
906 		mnt->auth_flavor_len = 1;
907 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
908 		break;
909 	case Opt_sec_spkmp:
910 		mnt->auth_flavor_len = 1;
911 		mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
912 		break;
913 	default:
914 		return 0;
915 	}
916 
917 	return 1;
918 }
919 
920 static void nfs_parse_invalid_value(const char *option)
921 {
922 	dfprintk(MOUNT, "NFS:   bad value specified for %s option\n", option);
923 }
924 
925 /*
926  * Error-check and convert a string of mount options from user space into
927  * a data structure.  The whole mount string is processed; bad options are
928  * skipped as they are encountered.  If there were no errors, return 1;
929  * otherwise return 0 (zero).
930  */
931 static int nfs_parse_mount_options(char *raw,
932 				   struct nfs_parsed_mount_data *mnt)
933 {
934 	char *p, *string, *secdata;
935 	int rc, sloppy = 0, errors = 0;
936 
937 	if (!raw) {
938 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
939 		return 1;
940 	}
941 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
942 
943 	secdata = alloc_secdata();
944 	if (!secdata)
945 		goto out_nomem;
946 
947 	rc = security_sb_copy_data(raw, secdata);
948 	if (rc)
949 		goto out_security_failure;
950 
951 	rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
952 	if (rc)
953 		goto out_security_failure;
954 
955 	free_secdata(secdata);
956 
957 	while ((p = strsep(&raw, ",")) != NULL) {
958 		substring_t args[MAX_OPT_ARGS];
959 		int option, token;
960 
961 		if (!*p)
962 			continue;
963 
964 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
965 
966 		token = match_token(p, nfs_mount_option_tokens, args);
967 		switch (token) {
968 
969 		/*
970 		 * boolean options:  foo/nofoo
971 		 */
972 		case Opt_soft:
973 			mnt->flags |= NFS_MOUNT_SOFT;
974 			break;
975 		case Opt_hard:
976 			mnt->flags &= ~NFS_MOUNT_SOFT;
977 			break;
978 		case Opt_posix:
979 			mnt->flags |= NFS_MOUNT_POSIX;
980 			break;
981 		case Opt_noposix:
982 			mnt->flags &= ~NFS_MOUNT_POSIX;
983 			break;
984 		case Opt_cto:
985 			mnt->flags &= ~NFS_MOUNT_NOCTO;
986 			break;
987 		case Opt_nocto:
988 			mnt->flags |= NFS_MOUNT_NOCTO;
989 			break;
990 		case Opt_ac:
991 			mnt->flags &= ~NFS_MOUNT_NOAC;
992 			break;
993 		case Opt_noac:
994 			mnt->flags |= NFS_MOUNT_NOAC;
995 			break;
996 		case Opt_lock:
997 			mnt->flags &= ~NFS_MOUNT_NONLM;
998 			break;
999 		case Opt_nolock:
1000 			mnt->flags |= NFS_MOUNT_NONLM;
1001 			break;
1002 		case Opt_v2:
1003 			mnt->flags &= ~NFS_MOUNT_VER3;
1004 			break;
1005 		case Opt_v3:
1006 			mnt->flags |= NFS_MOUNT_VER3;
1007 			break;
1008 		case Opt_udp:
1009 			mnt->flags &= ~NFS_MOUNT_TCP;
1010 			mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1011 			break;
1012 		case Opt_tcp:
1013 			mnt->flags |= NFS_MOUNT_TCP;
1014 			mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1015 			break;
1016 		case Opt_rdma:
1017 			mnt->flags |= NFS_MOUNT_TCP; /* for side protocols */
1018 			mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1019 			break;
1020 		case Opt_acl:
1021 			mnt->flags &= ~NFS_MOUNT_NOACL;
1022 			break;
1023 		case Opt_noacl:
1024 			mnt->flags |= NFS_MOUNT_NOACL;
1025 			break;
1026 		case Opt_rdirplus:
1027 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
1028 			break;
1029 		case Opt_nordirplus:
1030 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
1031 			break;
1032 		case Opt_sharecache:
1033 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
1034 			break;
1035 		case Opt_nosharecache:
1036 			mnt->flags |= NFS_MOUNT_UNSHARED;
1037 			break;
1038 
1039 		/*
1040 		 * options that take numeric values
1041 		 */
1042 		case Opt_port:
1043 			if (match_int(args, &option) ||
1044 			    option < 0 || option > USHORT_MAX) {
1045 				errors++;
1046 				nfs_parse_invalid_value("port");
1047 			} else
1048 				mnt->nfs_server.port = option;
1049 			break;
1050 		case Opt_rsize:
1051 			if (match_int(args, &option) || option < 0) {
1052 				errors++;
1053 				nfs_parse_invalid_value("rsize");
1054 			} else
1055 				mnt->rsize = option;
1056 			break;
1057 		case Opt_wsize:
1058 			if (match_int(args, &option) || option < 0) {
1059 				errors++;
1060 				nfs_parse_invalid_value("wsize");
1061 			} else
1062 				mnt->wsize = option;
1063 			break;
1064 		case Opt_bsize:
1065 			if (match_int(args, &option) || option < 0) {
1066 				errors++;
1067 				nfs_parse_invalid_value("bsize");
1068 			} else
1069 				mnt->bsize = option;
1070 			break;
1071 		case Opt_timeo:
1072 			if (match_int(args, &option) || option <= 0) {
1073 				errors++;
1074 				nfs_parse_invalid_value("timeo");
1075 			} else
1076 				mnt->timeo = option;
1077 			break;
1078 		case Opt_retrans:
1079 			if (match_int(args, &option) || option <= 0) {
1080 				errors++;
1081 				nfs_parse_invalid_value("retrans");
1082 			} else
1083 				mnt->retrans = option;
1084 			break;
1085 		case Opt_acregmin:
1086 			if (match_int(args, &option) || option < 0) {
1087 				errors++;
1088 				nfs_parse_invalid_value("acregmin");
1089 			} else
1090 				mnt->acregmin = option;
1091 			break;
1092 		case Opt_acregmax:
1093 			if (match_int(args, &option) || option < 0) {
1094 				errors++;
1095 				nfs_parse_invalid_value("acregmax");
1096 			} else
1097 				mnt->acregmax = option;
1098 			break;
1099 		case Opt_acdirmin:
1100 			if (match_int(args, &option) || option < 0) {
1101 				errors++;
1102 				nfs_parse_invalid_value("acdirmin");
1103 			} else
1104 				mnt->acdirmin = option;
1105 			break;
1106 		case Opt_acdirmax:
1107 			if (match_int(args, &option) || option < 0) {
1108 				errors++;
1109 				nfs_parse_invalid_value("acdirmax");
1110 			} else
1111 				mnt->acdirmax = option;
1112 			break;
1113 		case Opt_actimeo:
1114 			if (match_int(args, &option) || option < 0) {
1115 				errors++;
1116 				nfs_parse_invalid_value("actimeo");
1117 			} else
1118 				mnt->acregmin = mnt->acregmax =
1119 				mnt->acdirmin = mnt->acdirmax = option;
1120 			break;
1121 		case Opt_namelen:
1122 			if (match_int(args, &option) || option < 0) {
1123 				errors++;
1124 				nfs_parse_invalid_value("namlen");
1125 			} else
1126 				mnt->namlen = option;
1127 			break;
1128 		case Opt_mountport:
1129 			if (match_int(args, &option) ||
1130 			    option < 0 || option > USHORT_MAX) {
1131 				errors++;
1132 				nfs_parse_invalid_value("mountport");
1133 			} else
1134 				mnt->mount_server.port = option;
1135 			break;
1136 		case Opt_mountvers:
1137 			if (match_int(args, &option) ||
1138 			    option < NFS_MNT_VERSION ||
1139 			    option > NFS_MNT3_VERSION) {
1140 				errors++;
1141 				nfs_parse_invalid_value("mountvers");
1142 			} else
1143 				mnt->mount_server.version = option;
1144 			break;
1145 		case Opt_nfsvers:
1146 			if (match_int(args, &option)) {
1147 				errors++;
1148 				nfs_parse_invalid_value("nfsvers");
1149 				break;
1150 			}
1151 			switch (option) {
1152 			case NFS2_VERSION:
1153 				mnt->flags &= ~NFS_MOUNT_VER3;
1154 				break;
1155 			case NFS3_VERSION:
1156 				mnt->flags |= NFS_MOUNT_VER3;
1157 				break;
1158 			default:
1159 				errors++;
1160 				nfs_parse_invalid_value("nfsvers");
1161 			}
1162 			break;
1163 
1164 		/*
1165 		 * options that take text values
1166 		 */
1167 		case Opt_sec:
1168 			string = match_strdup(args);
1169 			if (string == NULL)
1170 				goto out_nomem;
1171 			rc = nfs_parse_security_flavors(string, mnt);
1172 			kfree(string);
1173 			if (!rc) {
1174 				errors++;
1175 				dfprintk(MOUNT, "NFS:   unrecognized "
1176 						"security flavor\n");
1177 			}
1178 			break;
1179 		case Opt_proto:
1180 			string = match_strdup(args);
1181 			if (string == NULL)
1182 				goto out_nomem;
1183 			token = match_token(string,
1184 					    nfs_xprt_protocol_tokens, args);
1185 			kfree(string);
1186 
1187 			switch (token) {
1188 			case Opt_xprt_udp:
1189 				mnt->flags &= ~NFS_MOUNT_TCP;
1190 				mnt->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1191 				break;
1192 			case Opt_xprt_tcp:
1193 				mnt->flags |= NFS_MOUNT_TCP;
1194 				mnt->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1195 				break;
1196 			case Opt_xprt_rdma:
1197 				/* vector side protocols to TCP */
1198 				mnt->flags |= NFS_MOUNT_TCP;
1199 				mnt->nfs_server.protocol = XPRT_TRANSPORT_RDMA;
1200 				break;
1201 			default:
1202 				errors++;
1203 				dfprintk(MOUNT, "NFS:   unrecognized "
1204 						"transport protocol\n");
1205 			}
1206 			break;
1207 		case Opt_mountproto:
1208 			string = match_strdup(args);
1209 			if (string == NULL)
1210 				goto out_nomem;
1211 			token = match_token(string,
1212 					    nfs_xprt_protocol_tokens, args);
1213 			kfree(string);
1214 
1215 			switch (token) {
1216 			case Opt_xprt_udp:
1217 				mnt->mount_server.protocol = XPRT_TRANSPORT_UDP;
1218 				break;
1219 			case Opt_xprt_tcp:
1220 				mnt->mount_server.protocol = XPRT_TRANSPORT_TCP;
1221 				break;
1222 			case Opt_xprt_rdma: /* not used for side protocols */
1223 			default:
1224 				errors++;
1225 				dfprintk(MOUNT, "NFS:   unrecognized "
1226 						"transport protocol\n");
1227 			}
1228 			break;
1229 		case Opt_addr:
1230 			string = match_strdup(args);
1231 			if (string == NULL)
1232 				goto out_nomem;
1233 			nfs_parse_ip_address(string, strlen(string),
1234 					     (struct sockaddr *)
1235 						&mnt->nfs_server.address,
1236 					     &mnt->nfs_server.addrlen);
1237 			kfree(string);
1238 			break;
1239 		case Opt_clientaddr:
1240 			string = match_strdup(args);
1241 			if (string == NULL)
1242 				goto out_nomem;
1243 			kfree(mnt->client_address);
1244 			mnt->client_address = string;
1245 			break;
1246 		case Opt_mounthost:
1247 			string = match_strdup(args);
1248 			if (string == NULL)
1249 				goto out_nomem;
1250 			kfree(mnt->mount_server.hostname);
1251 			mnt->mount_server.hostname = string;
1252 			break;
1253 		case Opt_mountaddr:
1254 			string = match_strdup(args);
1255 			if (string == NULL)
1256 				goto out_nomem;
1257 			nfs_parse_ip_address(string, strlen(string),
1258 					     (struct sockaddr *)
1259 						&mnt->mount_server.address,
1260 					     &mnt->mount_server.addrlen);
1261 			kfree(string);
1262 			break;
1263 		case Opt_lookupcache:
1264 			string = match_strdup(args);
1265 			if (string == NULL)
1266 				goto out_nomem;
1267 			token = match_token(string,
1268 					nfs_lookupcache_tokens, args);
1269 			kfree(string);
1270 			switch (token) {
1271 				case Opt_lookupcache_all:
1272 					mnt->flags &= ~(NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE);
1273 					break;
1274 				case Opt_lookupcache_positive:
1275 					mnt->flags &= ~NFS_MOUNT_LOOKUP_CACHE_NONE;
1276 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG;
1277 					break;
1278 				case Opt_lookupcache_none:
1279 					mnt->flags |= NFS_MOUNT_LOOKUP_CACHE_NONEG|NFS_MOUNT_LOOKUP_CACHE_NONE;
1280 					break;
1281 				default:
1282 					errors++;
1283 					dfprintk(MOUNT, "NFS:   invalid "
1284 							"lookupcache argument\n");
1285 			};
1286 			break;
1287 
1288 		/*
1289 		 * Special options
1290 		 */
1291 		case Opt_sloppy:
1292 			sloppy = 1;
1293 			dfprintk(MOUNT, "NFS:   relaxing parsing rules\n");
1294 			break;
1295 		case Opt_userspace:
1296 		case Opt_deprecated:
1297 			dfprintk(MOUNT, "NFS:   ignoring mount option "
1298 					"'%s'\n", p);
1299 			break;
1300 
1301 		default:
1302 			errors++;
1303 			dfprintk(MOUNT, "NFS:   unrecognized mount option "
1304 					"'%s'\n", p);
1305 		}
1306 	}
1307 
1308 	if (errors > 0) {
1309 		dfprintk(MOUNT, "NFS: parsing encountered %d error%s\n",
1310 				errors, (errors == 1 ? "" : "s"));
1311 		if (!sloppy)
1312 			return 0;
1313 	}
1314 	return 1;
1315 
1316 out_nomem:
1317 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
1318 	return 0;
1319 out_security_failure:
1320 	free_secdata(secdata);
1321 	printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
1322 	return 0;
1323 }
1324 
1325 /*
1326  * Use the remote server's MOUNT service to request the NFS file handle
1327  * corresponding to the provided path.
1328  */
1329 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1330 			 struct nfs_fh *root_fh)
1331 {
1332 	struct sockaddr *sap = (struct sockaddr *)&args->mount_server.address;
1333 	char *hostname;
1334 	int status;
1335 
1336 	if (args->mount_server.version == 0) {
1337 		if (args->flags & NFS_MOUNT_VER3)
1338 			args->mount_server.version = NFS_MNT3_VERSION;
1339 		else
1340 			args->mount_server.version = NFS_MNT_VERSION;
1341 	}
1342 
1343 	if (args->mount_server.hostname)
1344 		hostname = args->mount_server.hostname;
1345 	else
1346 		hostname = args->nfs_server.hostname;
1347 
1348 	/*
1349 	 * Construct the mount server's address.
1350 	 */
1351 	if (args->mount_server.address.ss_family == AF_UNSPEC) {
1352 		memcpy(sap, &args->nfs_server.address,
1353 		       args->nfs_server.addrlen);
1354 		args->mount_server.addrlen = args->nfs_server.addrlen;
1355 	}
1356 
1357 	/*
1358 	 * autobind will be used if mount_server.port == 0
1359 	 */
1360 	nfs_set_port(sap, args->mount_server.port);
1361 
1362 	/*
1363 	 * Now ask the mount server to map our export path
1364 	 * to a file handle.
1365 	 */
1366 	status = nfs_mount(sap,
1367 			   args->mount_server.addrlen,
1368 			   hostname,
1369 			   args->nfs_server.export_path,
1370 			   args->mount_server.version,
1371 			   args->mount_server.protocol,
1372 			   root_fh);
1373 	if (status == 0)
1374 		return 0;
1375 
1376 	dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n",
1377 			hostname, status);
1378 	return status;
1379 }
1380 
1381 static int nfs_parse_simple_hostname(const char *dev_name,
1382 				     char **hostname, size_t maxnamlen,
1383 				     char **export_path, size_t maxpathlen)
1384 {
1385 	size_t len;
1386 	char *colon, *comma;
1387 
1388 	colon = strchr(dev_name, ':');
1389 	if (colon == NULL)
1390 		goto out_bad_devname;
1391 
1392 	len = colon - dev_name;
1393 	if (len > maxnamlen)
1394 		goto out_hostname;
1395 
1396 	/* N.B. caller will free nfs_server.hostname in all cases */
1397 	*hostname = kstrndup(dev_name, len, GFP_KERNEL);
1398 	if (!*hostname)
1399 		goto out_nomem;
1400 
1401 	/* kill possible hostname list: not supported */
1402 	comma = strchr(*hostname, ',');
1403 	if (comma != NULL) {
1404 		if (comma == *hostname)
1405 			goto out_bad_devname;
1406 		*comma = '\0';
1407 	}
1408 
1409 	colon++;
1410 	len = strlen(colon);
1411 	if (len > maxpathlen)
1412 		goto out_path;
1413 	*export_path = kstrndup(colon, len, GFP_KERNEL);
1414 	if (!*export_path)
1415 		goto out_nomem;
1416 
1417 	dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
1418 	return 0;
1419 
1420 out_bad_devname:
1421 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1422 	return -EINVAL;
1423 
1424 out_nomem:
1425 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1426 	return -ENOMEM;
1427 
1428 out_hostname:
1429 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1430 	return -ENAMETOOLONG;
1431 
1432 out_path:
1433 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1434 	return -ENAMETOOLONG;
1435 }
1436 
1437 /*
1438  * Hostname has square brackets around it because it contains one or
1439  * more colons.  We look for the first closing square bracket, and a
1440  * colon must follow it.
1441  */
1442 static int nfs_parse_protected_hostname(const char *dev_name,
1443 					char **hostname, size_t maxnamlen,
1444 					char **export_path, size_t maxpathlen)
1445 {
1446 	size_t len;
1447 	char *start, *end;
1448 
1449 	start = (char *)(dev_name + 1);
1450 
1451 	end = strchr(start, ']');
1452 	if (end == NULL)
1453 		goto out_bad_devname;
1454 	if (*(end + 1) != ':')
1455 		goto out_bad_devname;
1456 
1457 	len = end - start;
1458 	if (len > maxnamlen)
1459 		goto out_hostname;
1460 
1461 	/* N.B. caller will free nfs_server.hostname in all cases */
1462 	*hostname = kstrndup(start, len, GFP_KERNEL);
1463 	if (*hostname == NULL)
1464 		goto out_nomem;
1465 
1466 	end += 2;
1467 	len = strlen(end);
1468 	if (len > maxpathlen)
1469 		goto out_path;
1470 	*export_path = kstrndup(end, len, GFP_KERNEL);
1471 	if (!*export_path)
1472 		goto out_nomem;
1473 
1474 	return 0;
1475 
1476 out_bad_devname:
1477 	dfprintk(MOUNT, "NFS: device name not in host:path format\n");
1478 	return -EINVAL;
1479 
1480 out_nomem:
1481 	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
1482 	return -ENOMEM;
1483 
1484 out_hostname:
1485 	dfprintk(MOUNT, "NFS: server hostname too long\n");
1486 	return -ENAMETOOLONG;
1487 
1488 out_path:
1489 	dfprintk(MOUNT, "NFS: export pathname too long\n");
1490 	return -ENAMETOOLONG;
1491 }
1492 
1493 /*
1494  * Split "dev_name" into "hostname:export_path".
1495  *
1496  * The leftmost colon demarks the split between the server's hostname
1497  * and the export path.  If the hostname starts with a left square
1498  * bracket, then it may contain colons.
1499  *
1500  * Note: caller frees hostname and export path, even on error.
1501  */
1502 static int nfs_parse_devname(const char *dev_name,
1503 			     char **hostname, size_t maxnamlen,
1504 			     char **export_path, size_t maxpathlen)
1505 {
1506 	if (*dev_name == '[')
1507 		return nfs_parse_protected_hostname(dev_name,
1508 						    hostname, maxnamlen,
1509 						    export_path, maxpathlen);
1510 
1511 	return nfs_parse_simple_hostname(dev_name,
1512 					 hostname, maxnamlen,
1513 					 export_path, maxpathlen);
1514 }
1515 
1516 /*
1517  * Validate the NFS2/NFS3 mount data
1518  * - fills in the mount root filehandle
1519  *
1520  * For option strings, user space handles the following behaviors:
1521  *
1522  * + DNS: mapping server host name to IP address ("addr=" option)
1523  *
1524  * + failure mode: how to behave if a mount request can't be handled
1525  *   immediately ("fg/bg" option)
1526  *
1527  * + retry: how often to retry a mount request ("retry=" option)
1528  *
1529  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1530  *   mountproto=tcp after mountproto=udp, and so on
1531  */
1532 static int nfs_validate_mount_data(void *options,
1533 				   struct nfs_parsed_mount_data *args,
1534 				   struct nfs_fh *mntfh,
1535 				   const char *dev_name)
1536 {
1537 	struct nfs_mount_data *data = (struct nfs_mount_data *)options;
1538 
1539 	if (data == NULL)
1540 		goto out_no_data;
1541 
1542 	args->flags		= (NFS_MOUNT_VER3 | NFS_MOUNT_TCP);
1543 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
1544 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
1545 	args->acregmin		= NFS_DEF_ACREGMIN;
1546 	args->acregmax		= NFS_DEF_ACREGMAX;
1547 	args->acdirmin		= NFS_DEF_ACDIRMIN;
1548 	args->acdirmax		= NFS_DEF_ACDIRMAX;
1549 	args->mount_server.port	= 0;	/* autobind unless user sets port */
1550 	args->nfs_server.port	= 0;	/* autobind unless user sets port */
1551 	args->nfs_server.protocol = XPRT_TRANSPORT_TCP;
1552 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
1553 
1554 	switch (data->version) {
1555 	case 1:
1556 		data->namlen = 0;
1557 	case 2:
1558 		data->bsize = 0;
1559 	case 3:
1560 		if (data->flags & NFS_MOUNT_VER3)
1561 			goto out_no_v3;
1562 		data->root.size = NFS2_FHSIZE;
1563 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1564 	case 4:
1565 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1566 			goto out_no_sec;
1567 	case 5:
1568 		memset(data->context, 0, sizeof(data->context));
1569 	case 6:
1570 		if (data->flags & NFS_MOUNT_VER3) {
1571 			if (data->root.size > NFS3_FHSIZE || data->root.size == 0)
1572 				goto out_invalid_fh;
1573 			mntfh->size = data->root.size;
1574 		} else
1575 			mntfh->size = NFS2_FHSIZE;
1576 
1577 
1578 		memcpy(mntfh->data, data->root.data, mntfh->size);
1579 		if (mntfh->size < sizeof(mntfh->data))
1580 			memset(mntfh->data + mntfh->size, 0,
1581 			       sizeof(mntfh->data) - mntfh->size);
1582 
1583 		/*
1584 		 * Translate to nfs_parsed_mount_data, which nfs_fill_super
1585 		 * can deal with.
1586 		 */
1587 		args->flags		= data->flags & NFS_MOUNT_FLAGMASK;
1588 		args->rsize		= data->rsize;
1589 		args->wsize		= data->wsize;
1590 		args->timeo		= data->timeo;
1591 		args->retrans		= data->retrans;
1592 		args->acregmin		= data->acregmin;
1593 		args->acregmax		= data->acregmax;
1594 		args->acdirmin		= data->acdirmin;
1595 		args->acdirmax		= data->acdirmax;
1596 
1597 		memcpy(&args->nfs_server.address, &data->addr,
1598 		       sizeof(data->addr));
1599 		args->nfs_server.addrlen = sizeof(data->addr);
1600 		if (!nfs_verify_server_address((struct sockaddr *)
1601 						&args->nfs_server.address))
1602 			goto out_no_address;
1603 
1604 		if (!(data->flags & NFS_MOUNT_TCP))
1605 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
1606 		/* N.B. caller will free nfs_server.hostname in all cases */
1607 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
1608 		args->namlen		= data->namlen;
1609 		args->bsize		= data->bsize;
1610 
1611 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1612 			args->auth_flavors[0] = data->pseudoflavor;
1613 		if (!args->nfs_server.hostname)
1614 			goto out_nomem;
1615 
1616 		/*
1617 		 * The legacy version 6 binary mount data from userspace has a
1618 		 * field used only to transport selinux information into the
1619 		 * the kernel.  To continue to support that functionality we
1620 		 * have a touch of selinux knowledge here in the NFS code. The
1621 		 * userspace code converted context=blah to just blah so we are
1622 		 * converting back to the full string selinux understands.
1623 		 */
1624 		if (data->context[0]){
1625 #ifdef CONFIG_SECURITY_SELINUX
1626 			int rc;
1627 			char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
1628 			if (!opts_str)
1629 				return -ENOMEM;
1630 			strcpy(opts_str, "context=");
1631 			data->context[NFS_MAX_CONTEXT_LEN] = '\0';
1632 			strcat(opts_str, &data->context[0]);
1633 			rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
1634 			kfree(opts_str);
1635 			if (rc)
1636 				return rc;
1637 #else
1638 			return -EINVAL;
1639 #endif
1640 		}
1641 
1642 		break;
1643 	default: {
1644 		int status;
1645 
1646 		if (nfs_parse_mount_options((char *)options, args) == 0)
1647 			return -EINVAL;
1648 
1649 		if (!nfs_verify_server_address((struct sockaddr *)
1650 						&args->nfs_server.address))
1651 			goto out_no_address;
1652 
1653 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
1654 				args->nfs_server.port);
1655 
1656 		nfs_set_mount_transport_protocol(args);
1657 
1658 		status = nfs_parse_devname(dev_name,
1659 					   &args->nfs_server.hostname,
1660 					   PAGE_SIZE,
1661 					   &args->nfs_server.export_path,
1662 					   NFS_MAXPATHLEN);
1663 		if (!status)
1664 			status = nfs_try_mount(args, mntfh);
1665 
1666 		kfree(args->nfs_server.export_path);
1667 		args->nfs_server.export_path = NULL;
1668 
1669 		if (status)
1670 			return status;
1671 
1672 		break;
1673 		}
1674 	}
1675 
1676 #ifndef CONFIG_NFS_V3
1677 	if (args->flags & NFS_MOUNT_VER3)
1678 		goto out_v3_not_compiled;
1679 #endif /* !CONFIG_NFS_V3 */
1680 
1681 	return 0;
1682 
1683 out_no_data:
1684 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1685 	return -EINVAL;
1686 
1687 out_no_v3:
1688 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1689 		 data->version);
1690 	return -EINVAL;
1691 
1692 out_no_sec:
1693 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1694 	return -EINVAL;
1695 
1696 #ifndef CONFIG_NFS_V3
1697 out_v3_not_compiled:
1698 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1699 	return -EPROTONOSUPPORT;
1700 #endif /* !CONFIG_NFS_V3 */
1701 
1702 out_nomem:
1703 	dfprintk(MOUNT, "NFS: not enough memory to handle mount options\n");
1704 	return -ENOMEM;
1705 
1706 out_no_address:
1707 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1708 	return -EINVAL;
1709 
1710 out_invalid_fh:
1711 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1712 	return -EINVAL;
1713 }
1714 
1715 static int
1716 nfs_compare_remount_data(struct nfs_server *nfss,
1717 			 struct nfs_parsed_mount_data *data)
1718 {
1719 	if (data->flags != nfss->flags ||
1720 	    data->rsize != nfss->rsize ||
1721 	    data->wsize != nfss->wsize ||
1722 	    data->retrans != nfss->client->cl_timeout->to_retries ||
1723 	    data->auth_flavors[0] != nfss->client->cl_auth->au_flavor ||
1724 	    data->acregmin != nfss->acregmin / HZ ||
1725 	    data->acregmax != nfss->acregmax / HZ ||
1726 	    data->acdirmin != nfss->acdirmin / HZ ||
1727 	    data->acdirmax != nfss->acdirmax / HZ ||
1728 	    data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
1729 	    data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
1730 	    memcmp(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1731 		   data->nfs_server.addrlen) != 0)
1732 		return -EINVAL;
1733 
1734 	return 0;
1735 }
1736 
1737 static int
1738 nfs_remount(struct super_block *sb, int *flags, char *raw_data)
1739 {
1740 	int error;
1741 	struct nfs_server *nfss = sb->s_fs_info;
1742 	struct nfs_parsed_mount_data *data;
1743 	struct nfs_mount_data *options = (struct nfs_mount_data *)raw_data;
1744 	struct nfs4_mount_data *options4 = (struct nfs4_mount_data *)raw_data;
1745 	u32 nfsvers = nfss->nfs_client->rpc_ops->version;
1746 
1747 	/*
1748 	 * Userspace mount programs that send binary options generally send
1749 	 * them populated with default values. We have no way to know which
1750 	 * ones were explicitly specified. Fall back to legacy behavior and
1751 	 * just return success.
1752 	 */
1753 	if ((nfsvers == 4 && (!options4 || options4->version == 1)) ||
1754 	    (nfsvers <= 3 && (!options || (options->version >= 1 &&
1755 					   options->version <= 6))))
1756 		return 0;
1757 
1758 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1759 	if (data == NULL)
1760 		return -ENOMEM;
1761 
1762 	/* fill out struct with values from existing mount */
1763 	data->flags = nfss->flags;
1764 	data->rsize = nfss->rsize;
1765 	data->wsize = nfss->wsize;
1766 	data->retrans = nfss->client->cl_timeout->to_retries;
1767 	data->auth_flavors[0] = nfss->client->cl_auth->au_flavor;
1768 	data->acregmin = nfss->acregmin / HZ;
1769 	data->acregmax = nfss->acregmax / HZ;
1770 	data->acdirmin = nfss->acdirmin / HZ;
1771 	data->acdirmax = nfss->acdirmax / HZ;
1772 	data->timeo = 10U * nfss->client->cl_timeout->to_initval / HZ;
1773 	data->nfs_server.addrlen = nfss->nfs_client->cl_addrlen;
1774 	memcpy(&data->nfs_server.address, &nfss->nfs_client->cl_addr,
1775 		data->nfs_server.addrlen);
1776 
1777 	/* overwrite those values with any that were specified */
1778 	error = nfs_parse_mount_options((char *)options, data);
1779 	if (error < 0)
1780 		goto out;
1781 
1782 	/* compare new mount options with old ones */
1783 	error = nfs_compare_remount_data(nfss, data);
1784 out:
1785 	kfree(data);
1786 	return error;
1787 }
1788 
1789 /*
1790  * Initialise the common bits of the superblock
1791  */
1792 static inline void nfs_initialise_sb(struct super_block *sb)
1793 {
1794 	struct nfs_server *server = NFS_SB(sb);
1795 
1796 	sb->s_magic = NFS_SUPER_MAGIC;
1797 
1798 	/* We probably want something more informative here */
1799 	snprintf(sb->s_id, sizeof(sb->s_id),
1800 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1801 
1802 	if (sb->s_blocksize == 0)
1803 		sb->s_blocksize = nfs_block_bits(server->wsize,
1804 						 &sb->s_blocksize_bits);
1805 
1806 	if (server->flags & NFS_MOUNT_NOAC)
1807 		sb->s_flags |= MS_SYNCHRONOUS;
1808 
1809 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1810 }
1811 
1812 /*
1813  * Finish setting up an NFS2/3 superblock
1814  */
1815 static void nfs_fill_super(struct super_block *sb,
1816 			   struct nfs_parsed_mount_data *data)
1817 {
1818 	struct nfs_server *server = NFS_SB(sb);
1819 
1820 	sb->s_blocksize_bits = 0;
1821 	sb->s_blocksize = 0;
1822 	if (data->bsize)
1823 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1824 
1825 	if (server->flags & NFS_MOUNT_VER3) {
1826 		/* The VFS shouldn't apply the umask to mode bits. We will do
1827 		 * so ourselves when necessary.
1828 		 */
1829 		sb->s_flags |= MS_POSIXACL;
1830 		sb->s_time_gran = 1;
1831 	}
1832 
1833 	sb->s_op = &nfs_sops;
1834  	nfs_initialise_sb(sb);
1835 }
1836 
1837 /*
1838  * Finish setting up a cloned NFS2/3 superblock
1839  */
1840 static void nfs_clone_super(struct super_block *sb,
1841 			    const struct super_block *old_sb)
1842 {
1843 	struct nfs_server *server = NFS_SB(sb);
1844 
1845 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1846 	sb->s_blocksize = old_sb->s_blocksize;
1847 	sb->s_maxbytes = old_sb->s_maxbytes;
1848 
1849 	if (server->flags & NFS_MOUNT_VER3) {
1850 		/* The VFS shouldn't apply the umask to mode bits. We will do
1851 		 * so ourselves when necessary.
1852 		 */
1853 		sb->s_flags |= MS_POSIXACL;
1854 		sb->s_time_gran = 1;
1855 	}
1856 
1857 	sb->s_op = old_sb->s_op;
1858  	nfs_initialise_sb(sb);
1859 }
1860 
1861 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1862 
1863 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1864 {
1865 	const struct nfs_server *a = s->s_fs_info;
1866 	const struct rpc_clnt *clnt_a = a->client;
1867 	const struct rpc_clnt *clnt_b = b->client;
1868 
1869 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1870 		goto Ebusy;
1871 	if (a->nfs_client != b->nfs_client)
1872 		goto Ebusy;
1873 	if (a->flags != b->flags)
1874 		goto Ebusy;
1875 	if (a->wsize != b->wsize)
1876 		goto Ebusy;
1877 	if (a->rsize != b->rsize)
1878 		goto Ebusy;
1879 	if (a->acregmin != b->acregmin)
1880 		goto Ebusy;
1881 	if (a->acregmax != b->acregmax)
1882 		goto Ebusy;
1883 	if (a->acdirmin != b->acdirmin)
1884 		goto Ebusy;
1885 	if (a->acdirmax != b->acdirmax)
1886 		goto Ebusy;
1887 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1888 		goto Ebusy;
1889 	return 1;
1890 Ebusy:
1891 	return 0;
1892 }
1893 
1894 struct nfs_sb_mountdata {
1895 	struct nfs_server *server;
1896 	int mntflags;
1897 };
1898 
1899 static int nfs_set_super(struct super_block *s, void *data)
1900 {
1901 	struct nfs_sb_mountdata *sb_mntdata = data;
1902 	struct nfs_server *server = sb_mntdata->server;
1903 	int ret;
1904 
1905 	s->s_flags = sb_mntdata->mntflags;
1906 	s->s_fs_info = server;
1907 	ret = set_anon_super(s, server);
1908 	if (ret == 0)
1909 		server->s_dev = s->s_dev;
1910 	return ret;
1911 }
1912 
1913 static int nfs_compare_super_address(struct nfs_server *server1,
1914 				     struct nfs_server *server2)
1915 {
1916 	struct sockaddr *sap1, *sap2;
1917 
1918 	sap1 = (struct sockaddr *)&server1->nfs_client->cl_addr;
1919 	sap2 = (struct sockaddr *)&server2->nfs_client->cl_addr;
1920 
1921 	if (sap1->sa_family != sap2->sa_family)
1922 		return 0;
1923 
1924 	switch (sap1->sa_family) {
1925 	case AF_INET: {
1926 		struct sockaddr_in *sin1 = (struct sockaddr_in *)sap1;
1927 		struct sockaddr_in *sin2 = (struct sockaddr_in *)sap2;
1928 		if (sin1->sin_addr.s_addr != sin2->sin_addr.s_addr)
1929 			return 0;
1930 		if (sin1->sin_port != sin2->sin_port)
1931 			return 0;
1932 		break;
1933 	}
1934 	case AF_INET6: {
1935 		struct sockaddr_in6 *sin1 = (struct sockaddr_in6 *)sap1;
1936 		struct sockaddr_in6 *sin2 = (struct sockaddr_in6 *)sap2;
1937 		if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
1938 			return 0;
1939 		if (sin1->sin6_port != sin2->sin6_port)
1940 			return 0;
1941 		break;
1942 	}
1943 	default:
1944 		return 0;
1945 	}
1946 
1947 	return 1;
1948 }
1949 
1950 static int nfs_compare_super(struct super_block *sb, void *data)
1951 {
1952 	struct nfs_sb_mountdata *sb_mntdata = data;
1953 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1954 	int mntflags = sb_mntdata->mntflags;
1955 
1956 	if (!nfs_compare_super_address(old, server))
1957 		return 0;
1958 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1959 	if (old->flags & NFS_MOUNT_UNSHARED)
1960 		return 0;
1961 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1962 		return 0;
1963 	return nfs_compare_mount_options(sb, server, mntflags);
1964 }
1965 
1966 static int nfs_bdi_register(struct nfs_server *server)
1967 {
1968 	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
1969 }
1970 
1971 static int nfs_get_sb(struct file_system_type *fs_type,
1972 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1973 {
1974 	struct nfs_server *server = NULL;
1975 	struct super_block *s;
1976 	struct nfs_parsed_mount_data *data;
1977 	struct nfs_fh *mntfh;
1978 	struct dentry *mntroot;
1979 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1980 	struct nfs_sb_mountdata sb_mntdata = {
1981 		.mntflags = flags,
1982 	};
1983 	int error = -ENOMEM;
1984 
1985 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1986 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
1987 	if (data == NULL || mntfh == NULL)
1988 		goto out_free_fh;
1989 
1990 	security_init_mnt_opts(&data->lsm_opts);
1991 
1992 	/* Validate the mount data */
1993 	error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
1994 	if (error < 0)
1995 		goto out;
1996 
1997 	/* Get a volume representation */
1998 	server = nfs_create_server(data, mntfh);
1999 	if (IS_ERR(server)) {
2000 		error = PTR_ERR(server);
2001 		goto out;
2002 	}
2003 	sb_mntdata.server = server;
2004 
2005 	if (server->flags & NFS_MOUNT_UNSHARED)
2006 		compare_super = NULL;
2007 
2008 	/* Get a superblock - note that we may end up sharing one that already exists */
2009 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2010 	if (IS_ERR(s)) {
2011 		error = PTR_ERR(s);
2012 		goto out_err_nosb;
2013 	}
2014 
2015 	if (s->s_fs_info != server) {
2016 		nfs_free_server(server);
2017 		server = NULL;
2018 	} else {
2019 		error = nfs_bdi_register(server);
2020 		if (error)
2021 			goto error_splat_super;
2022 	}
2023 
2024 	if (!s->s_root) {
2025 		/* initial superblock/root creation */
2026 		nfs_fill_super(s, data);
2027 	}
2028 
2029 	mntroot = nfs_get_root(s, mntfh);
2030 	if (IS_ERR(mntroot)) {
2031 		error = PTR_ERR(mntroot);
2032 		goto error_splat_super;
2033 	}
2034 
2035 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2036 	if (error)
2037 		goto error_splat_root;
2038 
2039 	s->s_flags |= MS_ACTIVE;
2040 	mnt->mnt_sb = s;
2041 	mnt->mnt_root = mntroot;
2042 	error = 0;
2043 
2044 out:
2045 	kfree(data->nfs_server.hostname);
2046 	kfree(data->mount_server.hostname);
2047 	security_free_mnt_opts(&data->lsm_opts);
2048 out_free_fh:
2049 	kfree(mntfh);
2050 	kfree(data);
2051 	return error;
2052 
2053 out_err_nosb:
2054 	nfs_free_server(server);
2055 	goto out;
2056 
2057 error_splat_root:
2058 	dput(mntroot);
2059 error_splat_super:
2060 	up_write(&s->s_umount);
2061 	deactivate_super(s);
2062 	goto out;
2063 }
2064 
2065 /*
2066  * Destroy an NFS2/3 superblock
2067  */
2068 static void nfs_kill_super(struct super_block *s)
2069 {
2070 	struct nfs_server *server = NFS_SB(s);
2071 
2072 	bdi_unregister(&server->backing_dev_info);
2073 	kill_anon_super(s);
2074 	nfs_free_server(server);
2075 }
2076 
2077 /*
2078  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
2079  */
2080 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
2081 			   const char *dev_name, void *raw_data,
2082 			   struct vfsmount *mnt)
2083 {
2084 	struct nfs_clone_mount *data = raw_data;
2085 	struct super_block *s;
2086 	struct nfs_server *server;
2087 	struct dentry *mntroot;
2088 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2089 	struct nfs_sb_mountdata sb_mntdata = {
2090 		.mntflags = flags,
2091 	};
2092 	int error;
2093 
2094 	dprintk("--> nfs_xdev_get_sb()\n");
2095 
2096 	/* create a new volume representation */
2097 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2098 	if (IS_ERR(server)) {
2099 		error = PTR_ERR(server);
2100 		goto out_err_noserver;
2101 	}
2102 	sb_mntdata.server = server;
2103 
2104 	if (server->flags & NFS_MOUNT_UNSHARED)
2105 		compare_super = NULL;
2106 
2107 	/* Get a superblock - note that we may end up sharing one that already exists */
2108 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2109 	if (IS_ERR(s)) {
2110 		error = PTR_ERR(s);
2111 		goto out_err_nosb;
2112 	}
2113 
2114 	if (s->s_fs_info != server) {
2115 		nfs_free_server(server);
2116 		server = NULL;
2117 	} else {
2118 		error = nfs_bdi_register(server);
2119 		if (error)
2120 			goto error_splat_super;
2121 	}
2122 
2123 	if (!s->s_root) {
2124 		/* initial superblock/root creation */
2125 		nfs_clone_super(s, data->sb);
2126 	}
2127 
2128 	mntroot = nfs_get_root(s, data->fh);
2129 	if (IS_ERR(mntroot)) {
2130 		error = PTR_ERR(mntroot);
2131 		goto error_splat_super;
2132 	}
2133 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2134 		dput(mntroot);
2135 		error = -ESTALE;
2136 		goto error_splat_super;
2137 	}
2138 
2139 	s->s_flags |= MS_ACTIVE;
2140 	mnt->mnt_sb = s;
2141 	mnt->mnt_root = mntroot;
2142 
2143 	/* clone any lsm security options from the parent to the new sb */
2144 	security_sb_clone_mnt_opts(data->sb, s);
2145 
2146 	dprintk("<-- nfs_xdev_get_sb() = 0\n");
2147 	return 0;
2148 
2149 out_err_nosb:
2150 	nfs_free_server(server);
2151 out_err_noserver:
2152 	dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
2153 	return error;
2154 
2155 error_splat_super:
2156 	up_write(&s->s_umount);
2157 	deactivate_super(s);
2158 	dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
2159 	return error;
2160 }
2161 
2162 #ifdef CONFIG_NFS_V4
2163 
2164 /*
2165  * Finish setting up a cloned NFS4 superblock
2166  */
2167 static void nfs4_clone_super(struct super_block *sb,
2168 			    const struct super_block *old_sb)
2169 {
2170 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
2171 	sb->s_blocksize = old_sb->s_blocksize;
2172 	sb->s_maxbytes = old_sb->s_maxbytes;
2173 	sb->s_time_gran = 1;
2174 	sb->s_op = old_sb->s_op;
2175  	nfs_initialise_sb(sb);
2176 }
2177 
2178 /*
2179  * Set up an NFS4 superblock
2180  */
2181 static void nfs4_fill_super(struct super_block *sb)
2182 {
2183 	sb->s_time_gran = 1;
2184 	sb->s_op = &nfs4_sops;
2185 	nfs_initialise_sb(sb);
2186 }
2187 
2188 /*
2189  * Validate NFSv4 mount options
2190  */
2191 static int nfs4_validate_mount_data(void *options,
2192 				    struct nfs_parsed_mount_data *args,
2193 				    const char *dev_name)
2194 {
2195 	struct sockaddr_in *ap;
2196 	struct nfs4_mount_data *data = (struct nfs4_mount_data *)options;
2197 	char *c;
2198 
2199 	if (data == NULL)
2200 		goto out_no_data;
2201 
2202 	args->rsize		= NFS_MAX_FILE_IO_SIZE;
2203 	args->wsize		= NFS_MAX_FILE_IO_SIZE;
2204 	args->acregmin		= NFS_DEF_ACREGMIN;
2205 	args->acregmax		= NFS_DEF_ACREGMAX;
2206 	args->acdirmin		= NFS_DEF_ACDIRMIN;
2207 	args->acdirmax		= NFS_DEF_ACDIRMAX;
2208 	args->nfs_server.port	= NFS_PORT; /* 2049 unless user set port= */
2209 	args->auth_flavors[0]	= RPC_AUTH_UNIX;
2210 	args->auth_flavor_len	= 0;
2211 
2212 	switch (data->version) {
2213 	case 1:
2214 		ap = (struct sockaddr_in *)&args->nfs_server.address;
2215 		if (data->host_addrlen > sizeof(args->nfs_server.address))
2216 			goto out_no_address;
2217 		if (data->host_addrlen == 0)
2218 			goto out_no_address;
2219 		args->nfs_server.addrlen = data->host_addrlen;
2220 		if (copy_from_user(ap, data->host_addr, data->host_addrlen))
2221 			return -EFAULT;
2222 		if (!nfs_verify_server_address((struct sockaddr *)
2223 						&args->nfs_server.address))
2224 			goto out_no_address;
2225 
2226 		if (data->auth_flavourlen) {
2227 			if (data->auth_flavourlen > 1)
2228 				goto out_inval_auth;
2229 			if (copy_from_user(&args->auth_flavors[0],
2230 					   data->auth_flavours,
2231 					   sizeof(args->auth_flavors[0])))
2232 				return -EFAULT;
2233 		}
2234 
2235 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
2236 		if (IS_ERR(c))
2237 			return PTR_ERR(c);
2238 		args->nfs_server.hostname = c;
2239 
2240 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
2241 		if (IS_ERR(c))
2242 			return PTR_ERR(c);
2243 		args->nfs_server.export_path = c;
2244 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", c);
2245 
2246 		c = strndup_user(data->client_addr.data, 16);
2247 		if (IS_ERR(c))
2248 			return PTR_ERR(c);
2249 		args->client_address = c;
2250 
2251 		/*
2252 		 * Translate to nfs_parsed_mount_data, which nfs4_fill_super
2253 		 * can deal with.
2254 		 */
2255 
2256 		args->flags	= data->flags & NFS4_MOUNT_FLAGMASK;
2257 		args->rsize	= data->rsize;
2258 		args->wsize	= data->wsize;
2259 		args->timeo	= data->timeo;
2260 		args->retrans	= data->retrans;
2261 		args->acregmin	= data->acregmin;
2262 		args->acregmax	= data->acregmax;
2263 		args->acdirmin	= data->acdirmin;
2264 		args->acdirmax	= data->acdirmax;
2265 		args->nfs_server.protocol = data->proto;
2266 		nfs_validate_transport_protocol(args);
2267 
2268 		break;
2269 	default: {
2270 		int status;
2271 
2272 		if (nfs_parse_mount_options((char *)options, args) == 0)
2273 			return -EINVAL;
2274 
2275 		if (!nfs_verify_server_address((struct sockaddr *)
2276 						&args->nfs_server.address))
2277 			return -EINVAL;
2278 
2279 		nfs_set_port((struct sockaddr *)&args->nfs_server.address,
2280 				args->nfs_server.port);
2281 
2282 		nfs_validate_transport_protocol(args);
2283 
2284 		if (args->auth_flavor_len > 1)
2285 			goto out_inval_auth;
2286 
2287 		if (args->client_address == NULL)
2288 			goto out_no_client_address;
2289 
2290 		status = nfs_parse_devname(dev_name,
2291 					   &args->nfs_server.hostname,
2292 					   NFS4_MAXNAMLEN,
2293 					   &args->nfs_server.export_path,
2294 					   NFS4_MAXPATHLEN);
2295 		if (status < 0)
2296 			return status;
2297 
2298 		break;
2299 		}
2300 	}
2301 
2302 	return 0;
2303 
2304 out_no_data:
2305 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
2306 	return -EINVAL;
2307 
2308 out_inval_auth:
2309 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
2310 		 data->auth_flavourlen);
2311 	return -EINVAL;
2312 
2313 out_no_address:
2314 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
2315 	return -EINVAL;
2316 
2317 out_no_client_address:
2318 	dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
2319 	return -EINVAL;
2320 }
2321 
2322 /*
2323  * Get the superblock for an NFS4 mountpoint
2324  */
2325 static int nfs4_get_sb(struct file_system_type *fs_type,
2326 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
2327 {
2328 	struct nfs_parsed_mount_data *data;
2329 	struct super_block *s;
2330 	struct nfs_server *server;
2331 	struct nfs_fh *mntfh;
2332 	struct dentry *mntroot;
2333 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2334 	struct nfs_sb_mountdata sb_mntdata = {
2335 		.mntflags = flags,
2336 	};
2337 	int error = -ENOMEM;
2338 
2339 	data = kzalloc(sizeof(*data), GFP_KERNEL);
2340 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
2341 	if (data == NULL || mntfh == NULL)
2342 		goto out_free_fh;
2343 
2344 	security_init_mnt_opts(&data->lsm_opts);
2345 
2346 	/* Validate the mount data */
2347 	error = nfs4_validate_mount_data(raw_data, data, dev_name);
2348 	if (error < 0)
2349 		goto out;
2350 
2351 	/* Get a volume representation */
2352 	server = nfs4_create_server(data, mntfh);
2353 	if (IS_ERR(server)) {
2354 		error = PTR_ERR(server);
2355 		goto out;
2356 	}
2357 	sb_mntdata.server = server;
2358 
2359 	if (server->flags & NFS4_MOUNT_UNSHARED)
2360 		compare_super = NULL;
2361 
2362 	/* Get a superblock - note that we may end up sharing one that already exists */
2363 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
2364 	if (IS_ERR(s)) {
2365 		error = PTR_ERR(s);
2366 		goto out_free;
2367 	}
2368 
2369 	if (s->s_fs_info != server) {
2370 		nfs_free_server(server);
2371 		server = NULL;
2372 	} else {
2373 		error = nfs_bdi_register(server);
2374 		if (error)
2375 			goto error_splat_super;
2376 	}
2377 
2378 	if (!s->s_root) {
2379 		/* initial superblock/root creation */
2380 		nfs4_fill_super(s);
2381 	}
2382 
2383 	mntroot = nfs4_get_root(s, mntfh);
2384 	if (IS_ERR(mntroot)) {
2385 		error = PTR_ERR(mntroot);
2386 		goto error_splat_super;
2387 	}
2388 
2389 	error = security_sb_set_mnt_opts(s, &data->lsm_opts);
2390 	if (error)
2391 		goto error_splat_root;
2392 
2393 	s->s_flags |= MS_ACTIVE;
2394 	mnt->mnt_sb = s;
2395 	mnt->mnt_root = mntroot;
2396 	error = 0;
2397 
2398 out:
2399 	kfree(data->client_address);
2400 	kfree(data->nfs_server.export_path);
2401 	kfree(data->nfs_server.hostname);
2402 	security_free_mnt_opts(&data->lsm_opts);
2403 out_free_fh:
2404 	kfree(mntfh);
2405 	kfree(data);
2406 	return error;
2407 
2408 out_free:
2409 	nfs_free_server(server);
2410 	goto out;
2411 
2412 error_splat_root:
2413 	dput(mntroot);
2414 error_splat_super:
2415 	up_write(&s->s_umount);
2416 	deactivate_super(s);
2417 	goto out;
2418 }
2419 
2420 static void nfs4_kill_super(struct super_block *sb)
2421 {
2422 	struct nfs_server *server = NFS_SB(sb);
2423 
2424 	nfs_return_all_delegations(sb);
2425 	kill_anon_super(sb);
2426 
2427 	nfs4_renewd_prepare_shutdown(server);
2428 	nfs_free_server(server);
2429 }
2430 
2431 /*
2432  * Clone an NFS4 server record on xdev traversal (FSID-change)
2433  */
2434 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
2435 			    const char *dev_name, void *raw_data,
2436 			    struct vfsmount *mnt)
2437 {
2438 	struct nfs_clone_mount *data = raw_data;
2439 	struct super_block *s;
2440 	struct nfs_server *server;
2441 	struct dentry *mntroot;
2442 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2443 	struct nfs_sb_mountdata sb_mntdata = {
2444 		.mntflags = flags,
2445 	};
2446 	int error;
2447 
2448 	dprintk("--> nfs4_xdev_get_sb()\n");
2449 
2450 	/* create a new volume representation */
2451 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
2452 	if (IS_ERR(server)) {
2453 		error = PTR_ERR(server);
2454 		goto out_err_noserver;
2455 	}
2456 	sb_mntdata.server = server;
2457 
2458 	if (server->flags & NFS4_MOUNT_UNSHARED)
2459 		compare_super = NULL;
2460 
2461 	/* Get a superblock - note that we may end up sharing one that already exists */
2462 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2463 	if (IS_ERR(s)) {
2464 		error = PTR_ERR(s);
2465 		goto out_err_nosb;
2466 	}
2467 
2468 	if (s->s_fs_info != server) {
2469 		nfs_free_server(server);
2470 		server = NULL;
2471 	} else {
2472 		error = nfs_bdi_register(server);
2473 		if (error)
2474 			goto error_splat_super;
2475 	}
2476 
2477 	if (!s->s_root) {
2478 		/* initial superblock/root creation */
2479 		nfs4_clone_super(s, data->sb);
2480 	}
2481 
2482 	mntroot = nfs4_get_root(s, data->fh);
2483 	if (IS_ERR(mntroot)) {
2484 		error = PTR_ERR(mntroot);
2485 		goto error_splat_super;
2486 	}
2487 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2488 		dput(mntroot);
2489 		error = -ESTALE;
2490 		goto error_splat_super;
2491 	}
2492 
2493 	s->s_flags |= MS_ACTIVE;
2494 	mnt->mnt_sb = s;
2495 	mnt->mnt_root = mntroot;
2496 
2497 	security_sb_clone_mnt_opts(data->sb, s);
2498 
2499 	dprintk("<-- nfs4_xdev_get_sb() = 0\n");
2500 	return 0;
2501 
2502 out_err_nosb:
2503 	nfs_free_server(server);
2504 out_err_noserver:
2505 	dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
2506 	return error;
2507 
2508 error_splat_super:
2509 	up_write(&s->s_umount);
2510 	deactivate_super(s);
2511 	dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
2512 	return error;
2513 }
2514 
2515 /*
2516  * Create an NFS4 server record on referral traversal
2517  */
2518 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
2519 				const char *dev_name, void *raw_data,
2520 				struct vfsmount *mnt)
2521 {
2522 	struct nfs_clone_mount *data = raw_data;
2523 	struct super_block *s;
2524 	struct nfs_server *server;
2525 	struct dentry *mntroot;
2526 	struct nfs_fh mntfh;
2527 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
2528 	struct nfs_sb_mountdata sb_mntdata = {
2529 		.mntflags = flags,
2530 	};
2531 	int error;
2532 
2533 	dprintk("--> nfs4_referral_get_sb()\n");
2534 
2535 	/* create a new volume representation */
2536 	server = nfs4_create_referral_server(data, &mntfh);
2537 	if (IS_ERR(server)) {
2538 		error = PTR_ERR(server);
2539 		goto out_err_noserver;
2540 	}
2541 	sb_mntdata.server = server;
2542 
2543 	if (server->flags & NFS4_MOUNT_UNSHARED)
2544 		compare_super = NULL;
2545 
2546 	/* Get a superblock - note that we may end up sharing one that already exists */
2547 	s = sget(&nfs4_fs_type, compare_super, nfs_set_super, &sb_mntdata);
2548 	if (IS_ERR(s)) {
2549 		error = PTR_ERR(s);
2550 		goto out_err_nosb;
2551 	}
2552 
2553 	if (s->s_fs_info != server) {
2554 		nfs_free_server(server);
2555 		server = NULL;
2556 	} else {
2557 		error = nfs_bdi_register(server);
2558 		if (error)
2559 			goto error_splat_super;
2560 	}
2561 
2562 	if (!s->s_root) {
2563 		/* initial superblock/root creation */
2564 		nfs4_fill_super(s);
2565 	}
2566 
2567 	mntroot = nfs4_get_root(s, &mntfh);
2568 	if (IS_ERR(mntroot)) {
2569 		error = PTR_ERR(mntroot);
2570 		goto error_splat_super;
2571 	}
2572 	if (mntroot->d_inode->i_op != NFS_SB(s)->nfs_client->rpc_ops->dir_inode_ops) {
2573 		dput(mntroot);
2574 		error = -ESTALE;
2575 		goto error_splat_super;
2576 	}
2577 
2578 	s->s_flags |= MS_ACTIVE;
2579 	mnt->mnt_sb = s;
2580 	mnt->mnt_root = mntroot;
2581 
2582 	security_sb_clone_mnt_opts(data->sb, s);
2583 
2584 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
2585 	return 0;
2586 
2587 out_err_nosb:
2588 	nfs_free_server(server);
2589 out_err_noserver:
2590 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
2591 	return error;
2592 
2593 error_splat_super:
2594 	up_write(&s->s_umount);
2595 	deactivate_super(s);
2596 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
2597 	return error;
2598 }
2599 
2600 #endif /* CONFIG_NFS_V4 */
2601