xref: /linux/fs/nfs/super.c (revision 2b8232ce512105e28453f301d1510de8363bccd1)
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/nfs_fs.h>
37 #include <linux/nfs_mount.h>
38 #include <linux/nfs4_mount.h>
39 #include <linux/lockd/bind.h>
40 #include <linux/smp_lock.h>
41 #include <linux/seq_file.h>
42 #include <linux/mount.h>
43 #include <linux/nfs_idmap.h>
44 #include <linux/vfs.h>
45 #include <linux/inet.h>
46 #include <linux/nfs_xdr.h>
47 #include <linux/magic.h>
48 #include <linux/parser.h>
49 
50 #include <asm/system.h>
51 #include <asm/uaccess.h>
52 
53 #include "nfs4_fs.h"
54 #include "callback.h"
55 #include "delegation.h"
56 #include "iostat.h"
57 #include "internal.h"
58 
59 #define NFSDBG_FACILITY		NFSDBG_VFS
60 
61 
62 struct nfs_parsed_mount_data {
63 	int			flags;
64 	int			rsize, wsize;
65 	int			timeo, retrans;
66 	int			acregmin, acregmax,
67 				acdirmin, acdirmax;
68 	int			namlen;
69 	unsigned int		bsize;
70 	unsigned int		auth_flavor_len;
71 	rpc_authflavor_t	auth_flavors[1];
72 	char			*client_address;
73 
74 	struct {
75 		struct sockaddr_in	address;
76 		unsigned int		program;
77 		unsigned int		version;
78 		unsigned short		port;
79 		int			protocol;
80 	} mount_server;
81 
82 	struct {
83 		struct sockaddr_in	address;
84 		char			*hostname;
85 		char			*export_path;
86 		unsigned int		program;
87 		int			protocol;
88 	} nfs_server;
89 };
90 
91 enum {
92 	/* Mount options that take no arguments */
93 	Opt_soft, Opt_hard,
94 	Opt_intr, Opt_nointr,
95 	Opt_posix, Opt_noposix,
96 	Opt_cto, Opt_nocto,
97 	Opt_ac, Opt_noac,
98 	Opt_lock, Opt_nolock,
99 	Opt_v2, Opt_v3,
100 	Opt_udp, Opt_tcp,
101 	Opt_acl, Opt_noacl,
102 	Opt_rdirplus, Opt_nordirplus,
103 	Opt_sharecache, Opt_nosharecache,
104 
105 	/* Mount options that take integer arguments */
106 	Opt_port,
107 	Opt_rsize, Opt_wsize, Opt_bsize,
108 	Opt_timeo, Opt_retrans,
109 	Opt_acregmin, Opt_acregmax,
110 	Opt_acdirmin, Opt_acdirmax,
111 	Opt_actimeo,
112 	Opt_namelen,
113 	Opt_mountport,
114 	Opt_mountprog, Opt_mountvers,
115 	Opt_nfsprog, Opt_nfsvers,
116 
117 	/* Mount options that take string arguments */
118 	Opt_sec, Opt_proto, Opt_mountproto,
119 	Opt_addr, Opt_mounthost, Opt_clientaddr,
120 
121 	/* Mount options that are ignored */
122 	Opt_userspace, Opt_deprecated,
123 
124 	Opt_err
125 };
126 
127 static match_table_t nfs_mount_option_tokens = {
128 	{ Opt_userspace, "bg" },
129 	{ Opt_userspace, "fg" },
130 	{ Opt_soft, "soft" },
131 	{ Opt_hard, "hard" },
132 	{ Opt_intr, "intr" },
133 	{ Opt_nointr, "nointr" },
134 	{ Opt_posix, "posix" },
135 	{ Opt_noposix, "noposix" },
136 	{ Opt_cto, "cto" },
137 	{ Opt_nocto, "nocto" },
138 	{ Opt_ac, "ac" },
139 	{ Opt_noac, "noac" },
140 	{ Opt_lock, "lock" },
141 	{ Opt_nolock, "nolock" },
142 	{ Opt_v2, "v2" },
143 	{ Opt_v3, "v3" },
144 	{ Opt_udp, "udp" },
145 	{ Opt_tcp, "tcp" },
146 	{ Opt_acl, "acl" },
147 	{ Opt_noacl, "noacl" },
148 	{ Opt_rdirplus, "rdirplus" },
149 	{ Opt_nordirplus, "nordirplus" },
150 	{ Opt_sharecache, "sharecache" },
151 	{ Opt_nosharecache, "nosharecache" },
152 
153 	{ Opt_port, "port=%u" },
154 	{ Opt_rsize, "rsize=%u" },
155 	{ Opt_wsize, "wsize=%u" },
156 	{ Opt_bsize, "bsize=%u" },
157 	{ Opt_timeo, "timeo=%u" },
158 	{ Opt_retrans, "retrans=%u" },
159 	{ Opt_acregmin, "acregmin=%u" },
160 	{ Opt_acregmax, "acregmax=%u" },
161 	{ Opt_acdirmin, "acdirmin=%u" },
162 	{ Opt_acdirmax, "acdirmax=%u" },
163 	{ Opt_actimeo, "actimeo=%u" },
164 	{ Opt_userspace, "retry=%u" },
165 	{ Opt_namelen, "namlen=%u" },
166 	{ Opt_mountport, "mountport=%u" },
167 	{ Opt_mountprog, "mountprog=%u" },
168 	{ Opt_mountvers, "mountvers=%u" },
169 	{ Opt_nfsprog, "nfsprog=%u" },
170 	{ Opt_nfsvers, "nfsvers=%u" },
171 	{ Opt_nfsvers, "vers=%u" },
172 
173 	{ Opt_sec, "sec=%s" },
174 	{ Opt_proto, "proto=%s" },
175 	{ Opt_mountproto, "mountproto=%s" },
176 	{ Opt_addr, "addr=%s" },
177 	{ Opt_clientaddr, "clientaddr=%s" },
178 	{ Opt_mounthost, "mounthost=%s" },
179 
180 	{ Opt_err, NULL }
181 };
182 
183 enum {
184 	Opt_xprt_udp, Opt_xprt_tcp,
185 
186 	Opt_xprt_err
187 };
188 
189 static match_table_t nfs_xprt_protocol_tokens = {
190 	{ Opt_xprt_udp, "udp" },
191 	{ Opt_xprt_tcp, "tcp" },
192 
193 	{ Opt_xprt_err, NULL }
194 };
195 
196 enum {
197 	Opt_sec_none, Opt_sec_sys,
198 	Opt_sec_krb5, Opt_sec_krb5i, Opt_sec_krb5p,
199 	Opt_sec_lkey, Opt_sec_lkeyi, Opt_sec_lkeyp,
200 	Opt_sec_spkm, Opt_sec_spkmi, Opt_sec_spkmp,
201 
202 	Opt_sec_err
203 };
204 
205 static match_table_t nfs_secflavor_tokens = {
206 	{ Opt_sec_none, "none" },
207 	{ Opt_sec_none, "null" },
208 	{ Opt_sec_sys, "sys" },
209 
210 	{ Opt_sec_krb5, "krb5" },
211 	{ Opt_sec_krb5i, "krb5i" },
212 	{ Opt_sec_krb5p, "krb5p" },
213 
214 	{ Opt_sec_lkey, "lkey" },
215 	{ Opt_sec_lkeyi, "lkeyi" },
216 	{ Opt_sec_lkeyp, "lkeyp" },
217 
218 	{ Opt_sec_err, NULL }
219 };
220 
221 
222 static void nfs_umount_begin(struct vfsmount *, int);
223 static int  nfs_statfs(struct dentry *, struct kstatfs *);
224 static int  nfs_show_options(struct seq_file *, struct vfsmount *);
225 static int  nfs_show_stats(struct seq_file *, struct vfsmount *);
226 static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
227 static int nfs_xdev_get_sb(struct file_system_type *fs_type,
228 		int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
229 static void nfs_kill_super(struct super_block *);
230 
231 static struct file_system_type nfs_fs_type = {
232 	.owner		= THIS_MODULE,
233 	.name		= "nfs",
234 	.get_sb		= nfs_get_sb,
235 	.kill_sb	= nfs_kill_super,
236 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
237 };
238 
239 struct file_system_type nfs_xdev_fs_type = {
240 	.owner		= THIS_MODULE,
241 	.name		= "nfs",
242 	.get_sb		= nfs_xdev_get_sb,
243 	.kill_sb	= nfs_kill_super,
244 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
245 };
246 
247 static const struct super_operations nfs_sops = {
248 	.alloc_inode	= nfs_alloc_inode,
249 	.destroy_inode	= nfs_destroy_inode,
250 	.write_inode	= nfs_write_inode,
251 	.statfs		= nfs_statfs,
252 	.clear_inode	= nfs_clear_inode,
253 	.umount_begin	= nfs_umount_begin,
254 	.show_options	= nfs_show_options,
255 	.show_stats	= nfs_show_stats,
256 };
257 
258 #ifdef CONFIG_NFS_V4
259 static int nfs4_get_sb(struct file_system_type *fs_type,
260 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
261 static int nfs4_xdev_get_sb(struct file_system_type *fs_type,
262 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
263 static int nfs4_referral_get_sb(struct file_system_type *fs_type,
264 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt);
265 static void nfs4_kill_super(struct super_block *sb);
266 
267 static struct file_system_type nfs4_fs_type = {
268 	.owner		= THIS_MODULE,
269 	.name		= "nfs4",
270 	.get_sb		= nfs4_get_sb,
271 	.kill_sb	= nfs4_kill_super,
272 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
273 };
274 
275 struct file_system_type nfs4_xdev_fs_type = {
276 	.owner		= THIS_MODULE,
277 	.name		= "nfs4",
278 	.get_sb		= nfs4_xdev_get_sb,
279 	.kill_sb	= nfs4_kill_super,
280 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
281 };
282 
283 struct file_system_type nfs4_referral_fs_type = {
284 	.owner		= THIS_MODULE,
285 	.name		= "nfs4",
286 	.get_sb		= nfs4_referral_get_sb,
287 	.kill_sb	= nfs4_kill_super,
288 	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
289 };
290 
291 static const struct super_operations nfs4_sops = {
292 	.alloc_inode	= nfs_alloc_inode,
293 	.destroy_inode	= nfs_destroy_inode,
294 	.write_inode	= nfs_write_inode,
295 	.statfs		= nfs_statfs,
296 	.clear_inode	= nfs4_clear_inode,
297 	.umount_begin	= nfs_umount_begin,
298 	.show_options	= nfs_show_options,
299 	.show_stats	= nfs_show_stats,
300 };
301 #endif
302 
303 static struct shrinker acl_shrinker = {
304 	.shrink		= nfs_access_cache_shrinker,
305 	.seeks		= DEFAULT_SEEKS,
306 };
307 
308 /*
309  * Register the NFS filesystems
310  */
311 int __init register_nfs_fs(void)
312 {
313 	int ret;
314 
315         ret = register_filesystem(&nfs_fs_type);
316 	if (ret < 0)
317 		goto error_0;
318 
319 	ret = nfs_register_sysctl();
320 	if (ret < 0)
321 		goto error_1;
322 #ifdef CONFIG_NFS_V4
323 	ret = register_filesystem(&nfs4_fs_type);
324 	if (ret < 0)
325 		goto error_2;
326 #endif
327 	register_shrinker(&acl_shrinker);
328 	return 0;
329 
330 #ifdef CONFIG_NFS_V4
331 error_2:
332 	nfs_unregister_sysctl();
333 #endif
334 error_1:
335 	unregister_filesystem(&nfs_fs_type);
336 error_0:
337 	return ret;
338 }
339 
340 /*
341  * Unregister the NFS filesystems
342  */
343 void __exit unregister_nfs_fs(void)
344 {
345 	unregister_shrinker(&acl_shrinker);
346 #ifdef CONFIG_NFS_V4
347 	unregister_filesystem(&nfs4_fs_type);
348 #endif
349 	nfs_unregister_sysctl();
350 	unregister_filesystem(&nfs_fs_type);
351 }
352 
353 /*
354  * Deliver file system statistics to userspace
355  */
356 static int nfs_statfs(struct dentry *dentry, struct kstatfs *buf)
357 {
358 	struct nfs_server *server = NFS_SB(dentry->d_sb);
359 	unsigned char blockbits;
360 	unsigned long blockres;
361 	struct nfs_fh *fh = NFS_FH(dentry->d_inode);
362 	struct nfs_fattr fattr;
363 	struct nfs_fsstat res = {
364 			.fattr = &fattr,
365 	};
366 	int error;
367 
368 	lock_kernel();
369 
370 	error = server->nfs_client->rpc_ops->statfs(server, fh, &res);
371 	if (error < 0)
372 		goto out_err;
373 	buf->f_type = NFS_SUPER_MAGIC;
374 
375 	/*
376 	 * Current versions of glibc do not correctly handle the
377 	 * case where f_frsize != f_bsize.  Eventually we want to
378 	 * report the value of wtmult in this field.
379 	 */
380 	buf->f_frsize = dentry->d_sb->s_blocksize;
381 
382 	/*
383 	 * On most *nix systems, f_blocks, f_bfree, and f_bavail
384 	 * are reported in units of f_frsize.  Linux hasn't had
385 	 * an f_frsize field in its statfs struct until recently,
386 	 * thus historically Linux's sys_statfs reports these
387 	 * fields in units of f_bsize.
388 	 */
389 	buf->f_bsize = dentry->d_sb->s_blocksize;
390 	blockbits = dentry->d_sb->s_blocksize_bits;
391 	blockres = (1 << blockbits) - 1;
392 	buf->f_blocks = (res.tbytes + blockres) >> blockbits;
393 	buf->f_bfree = (res.fbytes + blockres) >> blockbits;
394 	buf->f_bavail = (res.abytes + blockres) >> blockbits;
395 
396 	buf->f_files = res.tfiles;
397 	buf->f_ffree = res.afiles;
398 
399 	buf->f_namelen = server->namelen;
400 
401 	unlock_kernel();
402 	return 0;
403 
404  out_err:
405 	dprintk("%s: statfs error = %d\n", __FUNCTION__, -error);
406 	unlock_kernel();
407 	return error;
408 }
409 
410 /*
411  * Map the security flavour number to a name
412  */
413 static const char *nfs_pseudoflavour_to_name(rpc_authflavor_t flavour)
414 {
415 	static const struct {
416 		rpc_authflavor_t flavour;
417 		const char *str;
418 	} sec_flavours[] = {
419 		{ RPC_AUTH_NULL, "null" },
420 		{ RPC_AUTH_UNIX, "sys" },
421 		{ RPC_AUTH_GSS_KRB5, "krb5" },
422 		{ RPC_AUTH_GSS_KRB5I, "krb5i" },
423 		{ RPC_AUTH_GSS_KRB5P, "krb5p" },
424 		{ RPC_AUTH_GSS_LKEY, "lkey" },
425 		{ RPC_AUTH_GSS_LKEYI, "lkeyi" },
426 		{ RPC_AUTH_GSS_LKEYP, "lkeyp" },
427 		{ RPC_AUTH_GSS_SPKM, "spkm" },
428 		{ RPC_AUTH_GSS_SPKMI, "spkmi" },
429 		{ RPC_AUTH_GSS_SPKMP, "spkmp" },
430 		{ UINT_MAX, "unknown" }
431 	};
432 	int i;
433 
434 	for (i = 0; sec_flavours[i].flavour != UINT_MAX; i++) {
435 		if (sec_flavours[i].flavour == flavour)
436 			break;
437 	}
438 	return sec_flavours[i].str;
439 }
440 
441 /*
442  * Describe the mount options in force on this server representation
443  */
444 static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, int showdefaults)
445 {
446 	static const struct proc_nfs_info {
447 		int flag;
448 		const char *str;
449 		const char *nostr;
450 	} nfs_info[] = {
451 		{ NFS_MOUNT_SOFT, ",soft", ",hard" },
452 		{ NFS_MOUNT_INTR, ",intr", "" },
453 		{ NFS_MOUNT_NOCTO, ",nocto", "" },
454 		{ NFS_MOUNT_NOAC, ",noac", "" },
455 		{ NFS_MOUNT_NONLM, ",nolock", "" },
456 		{ NFS_MOUNT_NOACL, ",noacl", "" },
457 		{ NFS_MOUNT_NORDIRPLUS, ",nordirplus", "" },
458 		{ NFS_MOUNT_UNSHARED, ",nosharecache", ""},
459 		{ 0, NULL, NULL }
460 	};
461 	const struct proc_nfs_info *nfs_infop;
462 	struct nfs_client *clp = nfss->nfs_client;
463 	char buf[12];
464 	const char *proto;
465 
466 	seq_printf(m, ",vers=%d", clp->rpc_ops->version);
467 	seq_printf(m, ",rsize=%d", nfss->rsize);
468 	seq_printf(m, ",wsize=%d", nfss->wsize);
469 	if (nfss->acregmin != 3*HZ || showdefaults)
470 		seq_printf(m, ",acregmin=%d", nfss->acregmin/HZ);
471 	if (nfss->acregmax != 60*HZ || showdefaults)
472 		seq_printf(m, ",acregmax=%d", nfss->acregmax/HZ);
473 	if (nfss->acdirmin != 30*HZ || showdefaults)
474 		seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
475 	if (nfss->acdirmax != 60*HZ || showdefaults)
476 		seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
477 	for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
478 		if (nfss->flags & nfs_infop->flag)
479 			seq_puts(m, nfs_infop->str);
480 		else
481 			seq_puts(m, nfs_infop->nostr);
482 	}
483 	switch (nfss->client->cl_xprt->prot) {
484 		case IPPROTO_TCP:
485 			proto = "tcp";
486 			break;
487 		case IPPROTO_UDP:
488 			proto = "udp";
489 			break;
490 		default:
491 			snprintf(buf, sizeof(buf), "%u", nfss->client->cl_xprt->prot);
492 			proto = buf;
493 	}
494 	seq_printf(m, ",proto=%s", proto);
495 	seq_printf(m, ",timeo=%lu", 10U * clp->retrans_timeo / HZ);
496 	seq_printf(m, ",retrans=%u", clp->retrans_count);
497 	seq_printf(m, ",sec=%s", nfs_pseudoflavour_to_name(nfss->client->cl_auth->au_flavor));
498 }
499 
500 /*
501  * Describe the mount options on this VFS mountpoint
502  */
503 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
504 {
505 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
506 
507 	nfs_show_mount_options(m, nfss, 0);
508 
509 	seq_puts(m, ",addr=");
510 	seq_escape(m, nfss->nfs_client->cl_hostname, " \t\n\\");
511 
512 	return 0;
513 }
514 
515 /*
516  * Present statistical information for this VFS mountpoint
517  */
518 static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
519 {
520 	int i, cpu;
521 	struct nfs_server *nfss = NFS_SB(mnt->mnt_sb);
522 	struct rpc_auth *auth = nfss->client->cl_auth;
523 	struct nfs_iostats totals = { };
524 
525 	seq_printf(m, "statvers=%s", NFS_IOSTAT_VERS);
526 
527 	/*
528 	 * Display all mount option settings
529 	 */
530 	seq_printf(m, "\n\topts:\t");
531 	seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? "ro" : "rw");
532 	seq_puts(m, mnt->mnt_sb->s_flags & MS_SYNCHRONOUS ? ",sync" : "");
533 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NOATIME ? ",noatime" : "");
534 	seq_puts(m, mnt->mnt_sb->s_flags & MS_NODIRATIME ? ",nodiratime" : "");
535 	nfs_show_mount_options(m, nfss, 1);
536 
537 	seq_printf(m, "\n\tage:\t%lu", (jiffies - nfss->mount_time) / HZ);
538 
539 	seq_printf(m, "\n\tcaps:\t");
540 	seq_printf(m, "caps=0x%x", nfss->caps);
541 	seq_printf(m, ",wtmult=%d", nfss->wtmult);
542 	seq_printf(m, ",dtsize=%d", nfss->dtsize);
543 	seq_printf(m, ",bsize=%d", nfss->bsize);
544 	seq_printf(m, ",namelen=%d", nfss->namelen);
545 
546 #ifdef CONFIG_NFS_V4
547 	if (nfss->nfs_client->cl_nfsversion == 4) {
548 		seq_printf(m, "\n\tnfsv4:\t");
549 		seq_printf(m, "bm0=0x%x", nfss->attr_bitmask[0]);
550 		seq_printf(m, ",bm1=0x%x", nfss->attr_bitmask[1]);
551 		seq_printf(m, ",acl=0x%x", nfss->acl_bitmask);
552 	}
553 #endif
554 
555 	/*
556 	 * Display security flavor in effect for this mount
557 	 */
558 	seq_printf(m, "\n\tsec:\tflavor=%d", auth->au_ops->au_flavor);
559 	if (auth->au_flavor)
560 		seq_printf(m, ",pseudoflavor=%d", auth->au_flavor);
561 
562 	/*
563 	 * Display superblock I/O counters
564 	 */
565 	for_each_possible_cpu(cpu) {
566 		struct nfs_iostats *stats;
567 
568 		preempt_disable();
569 		stats = per_cpu_ptr(nfss->io_stats, cpu);
570 
571 		for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
572 			totals.events[i] += stats->events[i];
573 		for (i = 0; i < __NFSIOS_BYTESMAX; i++)
574 			totals.bytes[i] += stats->bytes[i];
575 
576 		preempt_enable();
577 	}
578 
579 	seq_printf(m, "\n\tevents:\t");
580 	for (i = 0; i < __NFSIOS_COUNTSMAX; i++)
581 		seq_printf(m, "%lu ", totals.events[i]);
582 	seq_printf(m, "\n\tbytes:\t");
583 	for (i = 0; i < __NFSIOS_BYTESMAX; i++)
584 		seq_printf(m, "%Lu ", totals.bytes[i]);
585 	seq_printf(m, "\n");
586 
587 	rpc_print_iostats(m, nfss->client);
588 
589 	return 0;
590 }
591 
592 /*
593  * Begin unmount by attempting to remove all automounted mountpoints we added
594  * in response to xdev traversals and referrals
595  */
596 static void nfs_umount_begin(struct vfsmount *vfsmnt, int flags)
597 {
598 	struct nfs_server *server = NFS_SB(vfsmnt->mnt_sb);
599 	struct rpc_clnt *rpc;
600 
601 	shrink_submounts(vfsmnt, &nfs_automount_list);
602 
603 	if (!(flags & MNT_FORCE))
604 		return;
605 	/* -EIO all pending I/O */
606 	rpc = server->client_acl;
607 	if (!IS_ERR(rpc))
608 		rpc_killall_tasks(rpc);
609 	rpc = server->client;
610 	if (!IS_ERR(rpc))
611 		rpc_killall_tasks(rpc);
612 }
613 
614 /*
615  * Sanity-check a server address provided by the mount command
616  */
617 static int nfs_verify_server_address(struct sockaddr *addr)
618 {
619 	switch (addr->sa_family) {
620 	case AF_INET: {
621 		struct sockaddr_in *sa = (struct sockaddr_in *) addr;
622 		if (sa->sin_addr.s_addr != INADDR_ANY)
623 			return 1;
624 		break;
625 	}
626 	}
627 
628 	return 0;
629 }
630 
631 /*
632  * Error-check and convert a string of mount options from user space into
633  * a data structure
634  */
635 static int nfs_parse_mount_options(char *raw,
636 				   struct nfs_parsed_mount_data *mnt)
637 {
638 	char *p, *string;
639 
640 	if (!raw) {
641 		dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
642 		return 1;
643 	}
644 	dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
645 
646 	while ((p = strsep(&raw, ",")) != NULL) {
647 		substring_t args[MAX_OPT_ARGS];
648 		int option, token;
649 
650 		if (!*p)
651 			continue;
652 
653 		dfprintk(MOUNT, "NFS:   parsing nfs mount option '%s'\n", p);
654 
655 		token = match_token(p, nfs_mount_option_tokens, args);
656 		switch (token) {
657 		case Opt_soft:
658 			mnt->flags |= NFS_MOUNT_SOFT;
659 			break;
660 		case Opt_hard:
661 			mnt->flags &= ~NFS_MOUNT_SOFT;
662 			break;
663 		case Opt_intr:
664 			mnt->flags |= NFS_MOUNT_INTR;
665 			break;
666 		case Opt_nointr:
667 			mnt->flags &= ~NFS_MOUNT_INTR;
668 			break;
669 		case Opt_posix:
670 			mnt->flags |= NFS_MOUNT_POSIX;
671 			break;
672 		case Opt_noposix:
673 			mnt->flags &= ~NFS_MOUNT_POSIX;
674 			break;
675 		case Opt_cto:
676 			mnt->flags &= ~NFS_MOUNT_NOCTO;
677 			break;
678 		case Opt_nocto:
679 			mnt->flags |= NFS_MOUNT_NOCTO;
680 			break;
681 		case Opt_ac:
682 			mnt->flags &= ~NFS_MOUNT_NOAC;
683 			break;
684 		case Opt_noac:
685 			mnt->flags |= NFS_MOUNT_NOAC;
686 			break;
687 		case Opt_lock:
688 			mnt->flags &= ~NFS_MOUNT_NONLM;
689 			break;
690 		case Opt_nolock:
691 			mnt->flags |= NFS_MOUNT_NONLM;
692 			break;
693 		case Opt_v2:
694 			mnt->flags &= ~NFS_MOUNT_VER3;
695 			break;
696 		case Opt_v3:
697 			mnt->flags |= NFS_MOUNT_VER3;
698 			break;
699 		case Opt_udp:
700 			mnt->flags &= ~NFS_MOUNT_TCP;
701 			mnt->nfs_server.protocol = IPPROTO_UDP;
702 			mnt->timeo = 7;
703 			mnt->retrans = 5;
704 			break;
705 		case Opt_tcp:
706 			mnt->flags |= NFS_MOUNT_TCP;
707 			mnt->nfs_server.protocol = IPPROTO_TCP;
708 			mnt->timeo = 600;
709 			mnt->retrans = 2;
710 			break;
711 		case Opt_acl:
712 			mnt->flags &= ~NFS_MOUNT_NOACL;
713 			break;
714 		case Opt_noacl:
715 			mnt->flags |= NFS_MOUNT_NOACL;
716 			break;
717 		case Opt_rdirplus:
718 			mnt->flags &= ~NFS_MOUNT_NORDIRPLUS;
719 			break;
720 		case Opt_nordirplus:
721 			mnt->flags |= NFS_MOUNT_NORDIRPLUS;
722 			break;
723 		case Opt_sharecache:
724 			mnt->flags &= ~NFS_MOUNT_UNSHARED;
725 			break;
726 		case Opt_nosharecache:
727 			mnt->flags |= NFS_MOUNT_UNSHARED;
728 			break;
729 
730 		case Opt_port:
731 			if (match_int(args, &option))
732 				return 0;
733 			if (option < 0 || option > 65535)
734 				return 0;
735 			mnt->nfs_server.address.sin_port = htons(option);
736 			break;
737 		case Opt_rsize:
738 			if (match_int(args, &mnt->rsize))
739 				return 0;
740 			break;
741 		case Opt_wsize:
742 			if (match_int(args, &mnt->wsize))
743 				return 0;
744 			break;
745 		case Opt_bsize:
746 			if (match_int(args, &option))
747 				return 0;
748 			if (option < 0)
749 				return 0;
750 			mnt->bsize = option;
751 			break;
752 		case Opt_timeo:
753 			if (match_int(args, &mnt->timeo))
754 				return 0;
755 			break;
756 		case Opt_retrans:
757 			if (match_int(args, &mnt->retrans))
758 				return 0;
759 			break;
760 		case Opt_acregmin:
761 			if (match_int(args, &mnt->acregmin))
762 				return 0;
763 			break;
764 		case Opt_acregmax:
765 			if (match_int(args, &mnt->acregmax))
766 				return 0;
767 			break;
768 		case Opt_acdirmin:
769 			if (match_int(args, &mnt->acdirmin))
770 				return 0;
771 			break;
772 		case Opt_acdirmax:
773 			if (match_int(args, &mnt->acdirmax))
774 				return 0;
775 			break;
776 		case Opt_actimeo:
777 			if (match_int(args, &option))
778 				return 0;
779 			if (option < 0)
780 				return 0;
781 			mnt->acregmin =
782 			mnt->acregmax =
783 			mnt->acdirmin =
784 			mnt->acdirmax = option;
785 			break;
786 		case Opt_namelen:
787 			if (match_int(args, &mnt->namlen))
788 				return 0;
789 			break;
790 		case Opt_mountport:
791 			if (match_int(args, &option))
792 				return 0;
793 			if (option < 0 || option > 65535)
794 				return 0;
795 			mnt->mount_server.port = option;
796 			break;
797 		case Opt_mountprog:
798 			if (match_int(args, &option))
799 				return 0;
800 			if (option < 0)
801 				return 0;
802 			mnt->mount_server.program = option;
803 			break;
804 		case Opt_mountvers:
805 			if (match_int(args, &option))
806 				return 0;
807 			if (option < 0)
808 				return 0;
809 			mnt->mount_server.version = option;
810 			break;
811 		case Opt_nfsprog:
812 			if (match_int(args, &option))
813 				return 0;
814 			if (option < 0)
815 				return 0;
816 			mnt->nfs_server.program = option;
817 			break;
818 		case Opt_nfsvers:
819 			if (match_int(args, &option))
820 				return 0;
821 			switch (option) {
822 			case 2:
823 				mnt->flags &= ~NFS_MOUNT_VER3;
824 				break;
825 			case 3:
826 				mnt->flags |= NFS_MOUNT_VER3;
827 				break;
828 			default:
829 				goto out_unrec_vers;
830 			}
831 			break;
832 
833 		case Opt_sec:
834 			string = match_strdup(args);
835 			if (string == NULL)
836 				goto out_nomem;
837 			token = match_token(string, nfs_secflavor_tokens, args);
838 			kfree(string);
839 
840 			/*
841 			 * The flags setting is for v2/v3.  The flavor_len
842 			 * setting is for v4.  v2/v3 also need to know the
843 			 * difference between NULL and UNIX.
844 			 */
845 			switch (token) {
846 			case Opt_sec_none:
847 				mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
848 				mnt->auth_flavor_len = 0;
849 				mnt->auth_flavors[0] = RPC_AUTH_NULL;
850 				break;
851 			case Opt_sec_sys:
852 				mnt->flags &= ~NFS_MOUNT_SECFLAVOUR;
853 				mnt->auth_flavor_len = 0;
854 				mnt->auth_flavors[0] = RPC_AUTH_UNIX;
855 				break;
856 			case Opt_sec_krb5:
857 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
858 				mnt->auth_flavor_len = 1;
859 				mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5;
860 				break;
861 			case Opt_sec_krb5i:
862 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
863 				mnt->auth_flavor_len = 1;
864 				mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5I;
865 				break;
866 			case Opt_sec_krb5p:
867 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
868 				mnt->auth_flavor_len = 1;
869 				mnt->auth_flavors[0] = RPC_AUTH_GSS_KRB5P;
870 				break;
871 			case Opt_sec_lkey:
872 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
873 				mnt->auth_flavor_len = 1;
874 				mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEY;
875 				break;
876 			case Opt_sec_lkeyi:
877 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
878 				mnt->auth_flavor_len = 1;
879 				mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYI;
880 				break;
881 			case Opt_sec_lkeyp:
882 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
883 				mnt->auth_flavor_len = 1;
884 				mnt->auth_flavors[0] = RPC_AUTH_GSS_LKEYP;
885 				break;
886 			case Opt_sec_spkm:
887 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
888 				mnt->auth_flavor_len = 1;
889 				mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKM;
890 				break;
891 			case Opt_sec_spkmi:
892 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
893 				mnt->auth_flavor_len = 1;
894 				mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMI;
895 				break;
896 			case Opt_sec_spkmp:
897 				mnt->flags |= NFS_MOUNT_SECFLAVOUR;
898 				mnt->auth_flavor_len = 1;
899 				mnt->auth_flavors[0] = RPC_AUTH_GSS_SPKMP;
900 				break;
901 			default:
902 				goto out_unrec_sec;
903 			}
904 			break;
905 		case Opt_proto:
906 			string = match_strdup(args);
907 			if (string == NULL)
908 				goto out_nomem;
909 			token = match_token(string,
910 					    nfs_xprt_protocol_tokens, args);
911 			kfree(string);
912 
913 			switch (token) {
914 			case Opt_xprt_udp:
915 				mnt->flags &= ~NFS_MOUNT_TCP;
916 				mnt->nfs_server.protocol = IPPROTO_UDP;
917 				mnt->timeo = 7;
918 				mnt->retrans = 5;
919 				break;
920 			case Opt_xprt_tcp:
921 				mnt->flags |= NFS_MOUNT_TCP;
922 				mnt->nfs_server.protocol = IPPROTO_TCP;
923 				mnt->timeo = 600;
924 				mnt->retrans = 2;
925 				break;
926 			default:
927 				goto out_unrec_xprt;
928 			}
929 			break;
930 		case Opt_mountproto:
931 			string = match_strdup(args);
932 			if (string == NULL)
933 				goto out_nomem;
934 			token = match_token(string,
935 					    nfs_xprt_protocol_tokens, args);
936 			kfree(string);
937 
938 			switch (token) {
939 			case Opt_xprt_udp:
940 				mnt->mount_server.protocol = IPPROTO_UDP;
941 				break;
942 			case Opt_xprt_tcp:
943 				mnt->mount_server.protocol = IPPROTO_TCP;
944 				break;
945 			default:
946 				goto out_unrec_xprt;
947 			}
948 			break;
949 		case Opt_addr:
950 			string = match_strdup(args);
951 			if (string == NULL)
952 				goto out_nomem;
953 			mnt->nfs_server.address.sin_family = AF_INET;
954 			mnt->nfs_server.address.sin_addr.s_addr =
955 							in_aton(string);
956 			kfree(string);
957 			break;
958 		case Opt_clientaddr:
959 			string = match_strdup(args);
960 			if (string == NULL)
961 				goto out_nomem;
962 			mnt->client_address = string;
963 			break;
964 		case Opt_mounthost:
965 			string = match_strdup(args);
966 			if (string == NULL)
967 				goto out_nomem;
968 			mnt->mount_server.address.sin_family = AF_INET;
969 			mnt->mount_server.address.sin_addr.s_addr =
970 							in_aton(string);
971 			kfree(string);
972 			break;
973 
974 		case Opt_userspace:
975 		case Opt_deprecated:
976 			break;
977 
978 		default:
979 			goto out_unknown;
980 		}
981 	}
982 
983 	return 1;
984 
985 out_nomem:
986 	printk(KERN_INFO "NFS: not enough memory to parse option\n");
987 	return 0;
988 
989 out_unrec_vers:
990 	printk(KERN_INFO "NFS: unrecognized NFS version number\n");
991 	return 0;
992 
993 out_unrec_xprt:
994 	printk(KERN_INFO "NFS: unrecognized transport protocol\n");
995 	return 0;
996 
997 out_unrec_sec:
998 	printk(KERN_INFO "NFS: unrecognized security flavor\n");
999 	return 0;
1000 
1001 out_unknown:
1002 	printk(KERN_INFO "NFS: unknown mount option: %s\n", p);
1003 	return 0;
1004 }
1005 
1006 /*
1007  * Use the remote server's MOUNT service to request the NFS file handle
1008  * corresponding to the provided path.
1009  */
1010 static int nfs_try_mount(struct nfs_parsed_mount_data *args,
1011 			 struct nfs_fh *root_fh)
1012 {
1013 	struct sockaddr_in sin;
1014 	int status;
1015 
1016 	if (args->mount_server.version == 0) {
1017 		if (args->flags & NFS_MOUNT_VER3)
1018 			args->mount_server.version = NFS_MNT3_VERSION;
1019 		else
1020 			args->mount_server.version = NFS_MNT_VERSION;
1021 	}
1022 
1023 	/*
1024 	 * Construct the mount server's address.
1025 	 */
1026 	if (args->mount_server.address.sin_addr.s_addr != INADDR_ANY)
1027 		sin = args->mount_server.address;
1028 	else
1029 		sin = args->nfs_server.address;
1030 	if (args->mount_server.port == 0) {
1031 		status = rpcb_getport_sync(&sin,
1032 					   args->mount_server.program,
1033 					   args->mount_server.version,
1034 					   args->mount_server.protocol);
1035 		if (status < 0)
1036 			goto out_err;
1037 		sin.sin_port = htons(status);
1038 	} else
1039 		sin.sin_port = htons(args->mount_server.port);
1040 
1041 	/*
1042 	 * Now ask the mount server to map our export path
1043 	 * to a file handle.
1044 	 */
1045 	status = nfs_mount((struct sockaddr *) &sin,
1046 			   sizeof(sin),
1047 			   args->nfs_server.hostname,
1048 			   args->nfs_server.export_path,
1049 			   args->mount_server.version,
1050 			   args->mount_server.protocol,
1051 			   root_fh);
1052 	if (status < 0)
1053 		goto out_err;
1054 
1055 	return status;
1056 
1057 out_err:
1058 	dfprintk(MOUNT, "NFS: unable to contact server on host "
1059 		 NIPQUAD_FMT "\n", NIPQUAD(sin.sin_addr.s_addr));
1060 	return status;
1061 }
1062 
1063 /*
1064  * Validate the NFS2/NFS3 mount data
1065  * - fills in the mount root filehandle
1066  *
1067  * For option strings, user space handles the following behaviors:
1068  *
1069  * + DNS: mapping server host name to IP address ("addr=" option)
1070  *
1071  * + failure mode: how to behave if a mount request can't be handled
1072  *   immediately ("fg/bg" option)
1073  *
1074  * + retry: how often to retry a mount request ("retry=" option)
1075  *
1076  * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
1077  *   mountproto=tcp after mountproto=udp, and so on
1078  *
1079  * XXX: as far as I can tell, changing the NFS program number is not
1080  *      supported in the NFS client.
1081  */
1082 static int nfs_validate_mount_data(struct nfs_mount_data **options,
1083 				   struct nfs_fh *mntfh,
1084 				   const char *dev_name)
1085 {
1086 	struct nfs_mount_data *data = *options;
1087 
1088 	if (data == NULL)
1089 		goto out_no_data;
1090 
1091 	switch (data->version) {
1092 	case 1:
1093 		data->namlen = 0;
1094 	case 2:
1095 		data->bsize = 0;
1096 	case 3:
1097 		if (data->flags & NFS_MOUNT_VER3)
1098 			goto out_no_v3;
1099 		data->root.size = NFS2_FHSIZE;
1100 		memcpy(data->root.data, data->old_root.data, NFS2_FHSIZE);
1101 	case 4:
1102 		if (data->flags & NFS_MOUNT_SECFLAVOUR)
1103 			goto out_no_sec;
1104 	case 5:
1105 		memset(data->context, 0, sizeof(data->context));
1106 	case 6:
1107 		if (data->flags & NFS_MOUNT_VER3)
1108 			mntfh->size = data->root.size;
1109 		else
1110 			mntfh->size = NFS2_FHSIZE;
1111 
1112 		if (mntfh->size > sizeof(mntfh->data))
1113 			goto out_invalid_fh;
1114 
1115 		memcpy(mntfh->data, data->root.data, mntfh->size);
1116 		if (mntfh->size < sizeof(mntfh->data))
1117 			memset(mntfh->data + mntfh->size, 0,
1118 			       sizeof(mntfh->data) - mntfh->size);
1119 		break;
1120 	default: {
1121 		unsigned int len;
1122 		char *c;
1123 		int status;
1124 		struct nfs_parsed_mount_data args = {
1125 			.flags		= (NFS_MOUNT_VER3 | NFS_MOUNT_TCP),
1126 			.rsize		= NFS_MAX_FILE_IO_SIZE,
1127 			.wsize		= NFS_MAX_FILE_IO_SIZE,
1128 			.timeo		= 600,
1129 			.retrans	= 2,
1130 			.acregmin	= 3,
1131 			.acregmax	= 60,
1132 			.acdirmin	= 30,
1133 			.acdirmax	= 60,
1134 			.mount_server.protocol = IPPROTO_UDP,
1135 			.mount_server.program = NFS_MNT_PROGRAM,
1136 			.nfs_server.protocol = IPPROTO_TCP,
1137 			.nfs_server.program = NFS_PROGRAM,
1138 		};
1139 
1140 		if (nfs_parse_mount_options((char *) *options, &args) == 0)
1141 			return -EINVAL;
1142 
1143 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1144 		if (data == NULL)
1145 			return -ENOMEM;
1146 
1147 		/*
1148 		 * NB: after this point, caller will free "data"
1149 		 * if we return an error
1150 		 */
1151 		*options = data;
1152 
1153 		c = strchr(dev_name, ':');
1154 		if (c == NULL)
1155 			return -EINVAL;
1156 		len = c - dev_name;
1157 		if (len > sizeof(data->hostname))
1158 			return -ENAMETOOLONG;
1159 		strncpy(data->hostname, dev_name, len);
1160 		args.nfs_server.hostname = data->hostname;
1161 
1162 		c++;
1163 		if (strlen(c) > NFS_MAXPATHLEN)
1164 			return -ENAMETOOLONG;
1165 		args.nfs_server.export_path = c;
1166 
1167 		status = nfs_try_mount(&args, mntfh);
1168 		if (status)
1169 			return status;
1170 
1171 		/*
1172 		 * Translate to nfs_mount_data, which nfs_fill_super
1173 		 * can deal with.
1174 		 */
1175 		data->version		= 6;
1176 		data->flags		= args.flags;
1177 		data->rsize		= args.rsize;
1178 		data->wsize		= args.wsize;
1179 		data->timeo		= args.timeo;
1180 		data->retrans		= args.retrans;
1181 		data->acregmin		= args.acregmin;
1182 		data->acregmax		= args.acregmax;
1183 		data->acdirmin		= args.acdirmin;
1184 		data->acdirmax		= args.acdirmax;
1185 		data->addr		= args.nfs_server.address;
1186 		data->namlen		= args.namlen;
1187 		data->bsize		= args.bsize;
1188 		data->pseudoflavor	= args.auth_flavors[0];
1189 
1190 		break;
1191 		}
1192 	}
1193 
1194 	if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
1195 		data->pseudoflavor = RPC_AUTH_UNIX;
1196 
1197 #ifndef CONFIG_NFS_V3
1198 	if (data->flags & NFS_MOUNT_VER3)
1199 		goto out_v3_not_compiled;
1200 #endif /* !CONFIG_NFS_V3 */
1201 
1202 	if (!nfs_verify_server_address((struct sockaddr *) &data->addr))
1203 		goto out_no_address;
1204 
1205 	return 0;
1206 
1207 out_no_data:
1208 	dfprintk(MOUNT, "NFS: mount program didn't pass any mount data\n");
1209 	return -EINVAL;
1210 
1211 out_no_v3:
1212 	dfprintk(MOUNT, "NFS: nfs_mount_data version %d does not support v3\n",
1213 		 data->version);
1214 	return -EINVAL;
1215 
1216 out_no_sec:
1217 	dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
1218 	return -EINVAL;
1219 
1220 #ifndef CONFIG_NFS_V3
1221 out_v3_not_compiled:
1222 	dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
1223 	return -EPROTONOSUPPORT;
1224 #endif /* !CONFIG_NFS_V3 */
1225 
1226 out_no_address:
1227 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
1228 	return -EINVAL;
1229 
1230 out_invalid_fh:
1231 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
1232 	return -EINVAL;
1233 }
1234 
1235 /*
1236  * Initialise the common bits of the superblock
1237  */
1238 static inline void nfs_initialise_sb(struct super_block *sb)
1239 {
1240 	struct nfs_server *server = NFS_SB(sb);
1241 
1242 	sb->s_magic = NFS_SUPER_MAGIC;
1243 
1244 	/* We probably want something more informative here */
1245 	snprintf(sb->s_id, sizeof(sb->s_id),
1246 		 "%x:%x", MAJOR(sb->s_dev), MINOR(sb->s_dev));
1247 
1248 	if (sb->s_blocksize == 0)
1249 		sb->s_blocksize = nfs_block_bits(server->wsize,
1250 						 &sb->s_blocksize_bits);
1251 
1252 	if (server->flags & NFS_MOUNT_NOAC)
1253 		sb->s_flags |= MS_SYNCHRONOUS;
1254 
1255 	nfs_super_set_maxbytes(sb, server->maxfilesize);
1256 }
1257 
1258 /*
1259  * Finish setting up an NFS2/3 superblock
1260  */
1261 static void nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data)
1262 {
1263 	struct nfs_server *server = NFS_SB(sb);
1264 
1265 	sb->s_blocksize_bits = 0;
1266 	sb->s_blocksize = 0;
1267 	if (data->bsize)
1268 		sb->s_blocksize = nfs_block_size(data->bsize, &sb->s_blocksize_bits);
1269 
1270 	if (server->flags & NFS_MOUNT_VER3) {
1271 		/* The VFS shouldn't apply the umask to mode bits. We will do
1272 		 * so ourselves when necessary.
1273 		 */
1274 		sb->s_flags |= MS_POSIXACL;
1275 		sb->s_time_gran = 1;
1276 	}
1277 
1278 	sb->s_op = &nfs_sops;
1279  	nfs_initialise_sb(sb);
1280 }
1281 
1282 /*
1283  * Finish setting up a cloned NFS2/3 superblock
1284  */
1285 static void nfs_clone_super(struct super_block *sb,
1286 			    const struct super_block *old_sb)
1287 {
1288 	struct nfs_server *server = NFS_SB(sb);
1289 
1290 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1291 	sb->s_blocksize = old_sb->s_blocksize;
1292 	sb->s_maxbytes = old_sb->s_maxbytes;
1293 
1294 	if (server->flags & NFS_MOUNT_VER3) {
1295 		/* The VFS shouldn't apply the umask to mode bits. We will do
1296 		 * so ourselves when necessary.
1297 		 */
1298 		sb->s_flags |= MS_POSIXACL;
1299 		sb->s_time_gran = 1;
1300 	}
1301 
1302 	sb->s_op = old_sb->s_op;
1303  	nfs_initialise_sb(sb);
1304 }
1305 
1306 #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
1307 
1308 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
1309 {
1310 	const struct nfs_server *a = s->s_fs_info;
1311 	const struct rpc_clnt *clnt_a = a->client;
1312 	const struct rpc_clnt *clnt_b = b->client;
1313 
1314 	if ((s->s_flags & NFS_MS_MASK) != (flags & NFS_MS_MASK))
1315 		goto Ebusy;
1316 	if (a->nfs_client != b->nfs_client)
1317 		goto Ebusy;
1318 	if (a->flags != b->flags)
1319 		goto Ebusy;
1320 	if (a->wsize != b->wsize)
1321 		goto Ebusy;
1322 	if (a->rsize != b->rsize)
1323 		goto Ebusy;
1324 	if (a->acregmin != b->acregmin)
1325 		goto Ebusy;
1326 	if (a->acregmax != b->acregmax)
1327 		goto Ebusy;
1328 	if (a->acdirmin != b->acdirmin)
1329 		goto Ebusy;
1330 	if (a->acdirmax != b->acdirmax)
1331 		goto Ebusy;
1332 	if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
1333 		goto Ebusy;
1334 	return 1;
1335 Ebusy:
1336 	return 0;
1337 }
1338 
1339 struct nfs_sb_mountdata {
1340 	struct nfs_server *server;
1341 	int mntflags;
1342 };
1343 
1344 static int nfs_set_super(struct super_block *s, void *data)
1345 {
1346 	struct nfs_sb_mountdata *sb_mntdata = data;
1347 	struct nfs_server *server = sb_mntdata->server;
1348 	int ret;
1349 
1350 	s->s_flags = sb_mntdata->mntflags;
1351 	s->s_fs_info = server;
1352 	ret = set_anon_super(s, server);
1353 	if (ret == 0)
1354 		server->s_dev = s->s_dev;
1355 	return ret;
1356 }
1357 
1358 static int nfs_compare_super(struct super_block *sb, void *data)
1359 {
1360 	struct nfs_sb_mountdata *sb_mntdata = data;
1361 	struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb);
1362 	int mntflags = sb_mntdata->mntflags;
1363 
1364 	if (memcmp(&old->nfs_client->cl_addr,
1365 				&server->nfs_client->cl_addr,
1366 				sizeof(old->nfs_client->cl_addr)) != 0)
1367 		return 0;
1368 	/* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */
1369 	if (old->flags & NFS_MOUNT_UNSHARED)
1370 		return 0;
1371 	if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0)
1372 		return 0;
1373 	return nfs_compare_mount_options(sb, server, mntflags);
1374 }
1375 
1376 static int nfs_get_sb(struct file_system_type *fs_type,
1377 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1378 {
1379 	struct nfs_server *server = NULL;
1380 	struct super_block *s;
1381 	struct nfs_fh mntfh;
1382 	struct nfs_mount_data *data = raw_data;
1383 	struct dentry *mntroot;
1384 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1385 	struct nfs_sb_mountdata sb_mntdata = {
1386 		.mntflags = flags,
1387 	};
1388 	int error;
1389 
1390 	/* Validate the mount data */
1391 	error = nfs_validate_mount_data(&data, &mntfh, dev_name);
1392 	if (error < 0)
1393 		goto out;
1394 
1395 	/* Get a volume representation */
1396 	server = nfs_create_server(data, &mntfh);
1397 	if (IS_ERR(server)) {
1398 		error = PTR_ERR(server);
1399 		goto out;
1400 	}
1401 	sb_mntdata.server = server;
1402 
1403 	if (server->flags & NFS_MOUNT_UNSHARED)
1404 		compare_super = NULL;
1405 
1406 	/* Get a superblock - note that we may end up sharing one that already exists */
1407 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1408 	if (IS_ERR(s)) {
1409 		error = PTR_ERR(s);
1410 		goto out_err_nosb;
1411 	}
1412 
1413 	if (s->s_fs_info != server) {
1414 		nfs_free_server(server);
1415 		server = NULL;
1416 	}
1417 
1418 	if (!s->s_root) {
1419 		/* initial superblock/root creation */
1420 		nfs_fill_super(s, data);
1421 	}
1422 
1423 	mntroot = nfs_get_root(s, &mntfh);
1424 	if (IS_ERR(mntroot)) {
1425 		error = PTR_ERR(mntroot);
1426 		goto error_splat_super;
1427 	}
1428 
1429 	s->s_flags |= MS_ACTIVE;
1430 	mnt->mnt_sb = s;
1431 	mnt->mnt_root = mntroot;
1432 	error = 0;
1433 
1434 out:
1435 	if (data != raw_data)
1436 		kfree(data);
1437 	return error;
1438 
1439 out_err_nosb:
1440 	nfs_free_server(server);
1441 	goto out;
1442 
1443 error_splat_super:
1444 	up_write(&s->s_umount);
1445 	deactivate_super(s);
1446 	goto out;
1447 }
1448 
1449 /*
1450  * Destroy an NFS2/3 superblock
1451  */
1452 static void nfs_kill_super(struct super_block *s)
1453 {
1454 	struct nfs_server *server = NFS_SB(s);
1455 
1456 	kill_anon_super(s);
1457 	nfs_free_server(server);
1458 }
1459 
1460 /*
1461  * Clone an NFS2/3 server record on xdev traversal (FSID-change)
1462  */
1463 static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
1464 			   const char *dev_name, void *raw_data,
1465 			   struct vfsmount *mnt)
1466 {
1467 	struct nfs_clone_mount *data = raw_data;
1468 	struct super_block *s;
1469 	struct nfs_server *server;
1470 	struct dentry *mntroot;
1471 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1472 	struct nfs_sb_mountdata sb_mntdata = {
1473 		.mntflags = flags,
1474 	};
1475 	int error;
1476 
1477 	dprintk("--> nfs_xdev_get_sb()\n");
1478 
1479 	/* create a new volume representation */
1480 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1481 	if (IS_ERR(server)) {
1482 		error = PTR_ERR(server);
1483 		goto out_err_noserver;
1484 	}
1485 	sb_mntdata.server = server;
1486 
1487 	if (server->flags & NFS_MOUNT_UNSHARED)
1488 		compare_super = NULL;
1489 
1490 	/* Get a superblock - note that we may end up sharing one that already exists */
1491 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1492 	if (IS_ERR(s)) {
1493 		error = PTR_ERR(s);
1494 		goto out_err_nosb;
1495 	}
1496 
1497 	if (s->s_fs_info != server) {
1498 		nfs_free_server(server);
1499 		server = NULL;
1500 	}
1501 
1502 	if (!s->s_root) {
1503 		/* initial superblock/root creation */
1504 		nfs_clone_super(s, data->sb);
1505 	}
1506 
1507 	mntroot = nfs_get_root(s, data->fh);
1508 	if (IS_ERR(mntroot)) {
1509 		error = PTR_ERR(mntroot);
1510 		goto error_splat_super;
1511 	}
1512 
1513 	s->s_flags |= MS_ACTIVE;
1514 	mnt->mnt_sb = s;
1515 	mnt->mnt_root = mntroot;
1516 
1517 	dprintk("<-- nfs_xdev_get_sb() = 0\n");
1518 	return 0;
1519 
1520 out_err_nosb:
1521 	nfs_free_server(server);
1522 out_err_noserver:
1523 	dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
1524 	return error;
1525 
1526 error_splat_super:
1527 	up_write(&s->s_umount);
1528 	deactivate_super(s);
1529 	dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
1530 	return error;
1531 }
1532 
1533 #ifdef CONFIG_NFS_V4
1534 
1535 /*
1536  * Finish setting up a cloned NFS4 superblock
1537  */
1538 static void nfs4_clone_super(struct super_block *sb,
1539 			    const struct super_block *old_sb)
1540 {
1541 	sb->s_blocksize_bits = old_sb->s_blocksize_bits;
1542 	sb->s_blocksize = old_sb->s_blocksize;
1543 	sb->s_maxbytes = old_sb->s_maxbytes;
1544 	sb->s_time_gran = 1;
1545 	sb->s_op = old_sb->s_op;
1546  	nfs_initialise_sb(sb);
1547 }
1548 
1549 /*
1550  * Set up an NFS4 superblock
1551  */
1552 static void nfs4_fill_super(struct super_block *sb)
1553 {
1554 	sb->s_time_gran = 1;
1555 	sb->s_op = &nfs4_sops;
1556 	nfs_initialise_sb(sb);
1557 }
1558 
1559 /*
1560  * Validate NFSv4 mount options
1561  */
1562 static int nfs4_validate_mount_data(struct nfs4_mount_data **options,
1563 				    const char *dev_name,
1564 				    struct sockaddr_in *addr,
1565 				    rpc_authflavor_t *authflavour,
1566 				    char **hostname,
1567 				    char **mntpath,
1568 				    char **ip_addr)
1569 {
1570 	struct nfs4_mount_data *data = *options;
1571 	char *c;
1572 
1573 	if (data == NULL)
1574 		goto out_no_data;
1575 
1576 	switch (data->version) {
1577 	case 1:
1578 		if (data->host_addrlen != sizeof(*addr))
1579 			goto out_no_address;
1580 		if (copy_from_user(addr, data->host_addr, sizeof(*addr)))
1581 			return -EFAULT;
1582 		if (addr->sin_port == 0)
1583 			addr->sin_port = htons(NFS_PORT);
1584 		if (!nfs_verify_server_address((struct sockaddr *) addr))
1585 			goto out_no_address;
1586 
1587 		switch (data->auth_flavourlen) {
1588 		case 0:
1589 			*authflavour = RPC_AUTH_UNIX;
1590 			break;
1591 		case 1:
1592 			if (copy_from_user(authflavour, data->auth_flavours,
1593 					   sizeof(*authflavour)))
1594 				return -EFAULT;
1595 			break;
1596 		default:
1597 			goto out_inval_auth;
1598 		}
1599 
1600 		c = strndup_user(data->hostname.data, NFS4_MAXNAMLEN);
1601 		if (IS_ERR(c))
1602 			return PTR_ERR(c);
1603 		*hostname = c;
1604 
1605 		c = strndup_user(data->mnt_path.data, NFS4_MAXPATHLEN);
1606 		if (IS_ERR(c))
1607 			return PTR_ERR(c);
1608 		*mntpath = c;
1609 		dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *mntpath);
1610 
1611 		c = strndup_user(data->client_addr.data, 16);
1612 		if (IS_ERR(c))
1613 			return PTR_ERR(c);
1614 		*ip_addr = c;
1615 
1616 		break;
1617 	default: {
1618 		unsigned int len;
1619 		struct nfs_parsed_mount_data args = {
1620 			.rsize		= NFS_MAX_FILE_IO_SIZE,
1621 			.wsize		= NFS_MAX_FILE_IO_SIZE,
1622 			.timeo		= 600,
1623 			.retrans	= 2,
1624 			.acregmin	= 3,
1625 			.acregmax	= 60,
1626 			.acdirmin	= 30,
1627 			.acdirmax	= 60,
1628 			.nfs_server.protocol = IPPROTO_TCP,
1629 		};
1630 
1631 		if (nfs_parse_mount_options((char *) *options, &args) == 0)
1632 			return -EINVAL;
1633 
1634 		if (!nfs_verify_server_address((struct sockaddr *)
1635 						&args.nfs_server.address))
1636 			return -EINVAL;
1637 		*addr = args.nfs_server.address;
1638 
1639 		switch (args.auth_flavor_len) {
1640 		case 0:
1641 			*authflavour = RPC_AUTH_UNIX;
1642 			break;
1643 		case 1:
1644 			*authflavour = (rpc_authflavor_t) args.auth_flavors[0];
1645 			break;
1646 		default:
1647 			goto out_inval_auth;
1648 		}
1649 
1650 		/*
1651 		 * Translate to nfs4_mount_data, which nfs4_fill_super
1652 		 * can deal with.
1653 		 */
1654 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1655 		if (data == NULL)
1656 			return -ENOMEM;
1657 		*options = data;
1658 
1659 		data->version	= 1;
1660 		data->flags	= args.flags & NFS4_MOUNT_FLAGMASK;
1661 		data->rsize	= args.rsize;
1662 		data->wsize	= args.wsize;
1663 		data->timeo	= args.timeo;
1664 		data->retrans	= args.retrans;
1665 		data->acregmin	= args.acregmin;
1666 		data->acregmax	= args.acregmax;
1667 		data->acdirmin	= args.acdirmin;
1668 		data->acdirmax	= args.acdirmax;
1669 		data->proto	= args.nfs_server.protocol;
1670 
1671 		/*
1672 		 * Split "dev_name" into "hostname:mntpath".
1673 		 */
1674 		c = strchr(dev_name, ':');
1675 		if (c == NULL)
1676 			return -EINVAL;
1677 		/* while calculating len, pretend ':' is '\0' */
1678 		len = c - dev_name;
1679 		if (len > NFS4_MAXNAMLEN)
1680 			return -ENAMETOOLONG;
1681 		*hostname = kzalloc(len, GFP_KERNEL);
1682 		if (*hostname == NULL)
1683 			return -ENOMEM;
1684 		strncpy(*hostname, dev_name, len - 1);
1685 
1686 		c++;			/* step over the ':' */
1687 		len = strlen(c);
1688 		if (len > NFS4_MAXPATHLEN)
1689 			return -ENAMETOOLONG;
1690 		*mntpath = kzalloc(len + 1, GFP_KERNEL);
1691 		if (*mntpath == NULL)
1692 			return -ENOMEM;
1693 		strncpy(*mntpath, c, len);
1694 
1695 		dprintk("MNTPATH: %s\n", *mntpath);
1696 
1697 		if (args.client_address == NULL)
1698 			goto out_no_client_address;
1699 
1700 		*ip_addr = args.client_address;
1701 
1702 		break;
1703 		}
1704 	}
1705 
1706 	return 0;
1707 
1708 out_no_data:
1709 	dfprintk(MOUNT, "NFS4: mount program didn't pass any mount data\n");
1710 	return -EINVAL;
1711 
1712 out_inval_auth:
1713 	dfprintk(MOUNT, "NFS4: Invalid number of RPC auth flavours %d\n",
1714 		 data->auth_flavourlen);
1715 	return -EINVAL;
1716 
1717 out_no_address:
1718 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
1719 	return -EINVAL;
1720 
1721 out_no_client_address:
1722 	dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");
1723 	return -EINVAL;
1724 }
1725 
1726 /*
1727  * Get the superblock for an NFS4 mountpoint
1728  */
1729 static int nfs4_get_sb(struct file_system_type *fs_type,
1730 	int flags, const char *dev_name, void *raw_data, struct vfsmount *mnt)
1731 {
1732 	struct nfs4_mount_data *data = raw_data;
1733 	struct super_block *s;
1734 	struct nfs_server *server;
1735 	struct sockaddr_in addr;
1736 	rpc_authflavor_t authflavour;
1737 	struct nfs_fh mntfh;
1738 	struct dentry *mntroot;
1739 	char *mntpath = NULL, *hostname = NULL, *ip_addr = NULL;
1740 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1741 	struct nfs_sb_mountdata sb_mntdata = {
1742 		.mntflags = flags,
1743 	};
1744 	int error;
1745 
1746 	/* Validate the mount data */
1747 	error = nfs4_validate_mount_data(&data, dev_name, &addr, &authflavour,
1748 					 &hostname, &mntpath, &ip_addr);
1749 	if (error < 0)
1750 		goto out;
1751 
1752 	/* Get a volume representation */
1753 	server = nfs4_create_server(data, hostname, &addr, mntpath, ip_addr,
1754 				    authflavour, &mntfh);
1755 	if (IS_ERR(server)) {
1756 		error = PTR_ERR(server);
1757 		goto out;
1758 	}
1759 	sb_mntdata.server = server;
1760 
1761 	if (server->flags & NFS4_MOUNT_UNSHARED)
1762 		compare_super = NULL;
1763 
1764 	/* Get a superblock - note that we may end up sharing one that already exists */
1765 	s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata);
1766 	if (IS_ERR(s)) {
1767 		error = PTR_ERR(s);
1768 		goto out_free;
1769 	}
1770 
1771 	if (s->s_fs_info != server) {
1772 		nfs_free_server(server);
1773 		server = NULL;
1774 	}
1775 
1776 	if (!s->s_root) {
1777 		/* initial superblock/root creation */
1778 		nfs4_fill_super(s);
1779 	}
1780 
1781 	mntroot = nfs4_get_root(s, &mntfh);
1782 	if (IS_ERR(mntroot)) {
1783 		error = PTR_ERR(mntroot);
1784 		goto error_splat_super;
1785 	}
1786 
1787 	s->s_flags |= MS_ACTIVE;
1788 	mnt->mnt_sb = s;
1789 	mnt->mnt_root = mntroot;
1790 	error = 0;
1791 
1792 out:
1793 	kfree(ip_addr);
1794 	kfree(mntpath);
1795 	kfree(hostname);
1796 	return error;
1797 
1798 out_free:
1799 	nfs_free_server(server);
1800 	goto out;
1801 
1802 error_splat_super:
1803 	up_write(&s->s_umount);
1804 	deactivate_super(s);
1805 	goto out;
1806 }
1807 
1808 static void nfs4_kill_super(struct super_block *sb)
1809 {
1810 	struct nfs_server *server = NFS_SB(sb);
1811 
1812 	nfs_return_all_delegations(sb);
1813 	kill_anon_super(sb);
1814 
1815 	nfs4_renewd_prepare_shutdown(server);
1816 	nfs_free_server(server);
1817 }
1818 
1819 /*
1820  * Clone an NFS4 server record on xdev traversal (FSID-change)
1821  */
1822 static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags,
1823 			    const char *dev_name, void *raw_data,
1824 			    struct vfsmount *mnt)
1825 {
1826 	struct nfs_clone_mount *data = raw_data;
1827 	struct super_block *s;
1828 	struct nfs_server *server;
1829 	struct dentry *mntroot;
1830 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1831 	struct nfs_sb_mountdata sb_mntdata = {
1832 		.mntflags = flags,
1833 	};
1834 	int error;
1835 
1836 	dprintk("--> nfs4_xdev_get_sb()\n");
1837 
1838 	/* create a new volume representation */
1839 	server = nfs_clone_server(NFS_SB(data->sb), data->fh, data->fattr);
1840 	if (IS_ERR(server)) {
1841 		error = PTR_ERR(server);
1842 		goto out_err_noserver;
1843 	}
1844 	sb_mntdata.server = server;
1845 
1846 	if (server->flags & NFS4_MOUNT_UNSHARED)
1847 		compare_super = NULL;
1848 
1849 	/* Get a superblock - note that we may end up sharing one that already exists */
1850 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1851 	if (IS_ERR(s)) {
1852 		error = PTR_ERR(s);
1853 		goto out_err_nosb;
1854 	}
1855 
1856 	if (s->s_fs_info != server) {
1857 		nfs_free_server(server);
1858 		server = NULL;
1859 	}
1860 
1861 	if (!s->s_root) {
1862 		/* initial superblock/root creation */
1863 		nfs4_clone_super(s, data->sb);
1864 	}
1865 
1866 	mntroot = nfs4_get_root(s, data->fh);
1867 	if (IS_ERR(mntroot)) {
1868 		error = PTR_ERR(mntroot);
1869 		goto error_splat_super;
1870 	}
1871 
1872 	s->s_flags |= MS_ACTIVE;
1873 	mnt->mnt_sb = s;
1874 	mnt->mnt_root = mntroot;
1875 
1876 	dprintk("<-- nfs4_xdev_get_sb() = 0\n");
1877 	return 0;
1878 
1879 out_err_nosb:
1880 	nfs_free_server(server);
1881 out_err_noserver:
1882 	dprintk("<-- nfs4_xdev_get_sb() = %d [error]\n", error);
1883 	return error;
1884 
1885 error_splat_super:
1886 	up_write(&s->s_umount);
1887 	deactivate_super(s);
1888 	dprintk("<-- nfs4_xdev_get_sb() = %d [splat]\n", error);
1889 	return error;
1890 }
1891 
1892 /*
1893  * Create an NFS4 server record on referral traversal
1894  */
1895 static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags,
1896 				const char *dev_name, void *raw_data,
1897 				struct vfsmount *mnt)
1898 {
1899 	struct nfs_clone_mount *data = raw_data;
1900 	struct super_block *s;
1901 	struct nfs_server *server;
1902 	struct dentry *mntroot;
1903 	struct nfs_fh mntfh;
1904 	int (*compare_super)(struct super_block *, void *) = nfs_compare_super;
1905 	struct nfs_sb_mountdata sb_mntdata = {
1906 		.mntflags = flags,
1907 	};
1908 	int error;
1909 
1910 	dprintk("--> nfs4_referral_get_sb()\n");
1911 
1912 	/* create a new volume representation */
1913 	server = nfs4_create_referral_server(data, &mntfh);
1914 	if (IS_ERR(server)) {
1915 		error = PTR_ERR(server);
1916 		goto out_err_noserver;
1917 	}
1918 	sb_mntdata.server = server;
1919 
1920 	if (server->flags & NFS4_MOUNT_UNSHARED)
1921 		compare_super = NULL;
1922 
1923 	/* Get a superblock - note that we may end up sharing one that already exists */
1924 	s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata);
1925 	if (IS_ERR(s)) {
1926 		error = PTR_ERR(s);
1927 		goto out_err_nosb;
1928 	}
1929 
1930 	if (s->s_fs_info != server) {
1931 		nfs_free_server(server);
1932 		server = NULL;
1933 	}
1934 
1935 	if (!s->s_root) {
1936 		/* initial superblock/root creation */
1937 		nfs4_fill_super(s);
1938 	}
1939 
1940 	mntroot = nfs4_get_root(s, &mntfh);
1941 	if (IS_ERR(mntroot)) {
1942 		error = PTR_ERR(mntroot);
1943 		goto error_splat_super;
1944 	}
1945 
1946 	s->s_flags |= MS_ACTIVE;
1947 	mnt->mnt_sb = s;
1948 	mnt->mnt_root = mntroot;
1949 
1950 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
1951 	return 0;
1952 
1953 out_err_nosb:
1954 	nfs_free_server(server);
1955 out_err_noserver:
1956 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
1957 	return error;
1958 
1959 error_splat_super:
1960 	up_write(&s->s_umount);
1961 	deactivate_super(s);
1962 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
1963 	return error;
1964 }
1965 
1966 #endif /* CONFIG_NFS_V4 */
1967