xref: /openbmc/linux/fs/nfsd/nfsfh.c (revision a5b2c10c)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * NFS server file handle treatment.
4  *
5  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
7  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
8  * ... and again Southern-Winter 2001 to support export_operations
9  */
10 
11 #include <linux/exportfs.h>
12 
13 #include <linux/sunrpc/svcauth_gss.h>
14 #include "nfsd.h"
15 #include "vfs.h"
16 #include "auth.h"
17 #include "trace.h"
18 
19 #define NFSDDBG_FACILITY		NFSDDBG_FH
20 
21 
22 /*
23  * our acceptability function.
24  * if NOSUBTREECHECK, accept anything
25  * if not, require that we can walk up to exp->ex_dentry
26  * doing some checks on the 'x' bits
27  */
28 static int nfsd_acceptable(void *expv, struct dentry *dentry)
29 {
30 	struct svc_export *exp = expv;
31 	int rv;
32 	struct dentry *tdentry;
33 	struct dentry *parent;
34 
35 	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
36 		return 1;
37 
38 	tdentry = dget(dentry);
39 	while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
40 		/* make sure parents give x permission to user */
41 		int err;
42 		parent = dget_parent(tdentry);
43 		err = inode_permission(d_inode(parent), MAY_EXEC);
44 		if (err < 0) {
45 			dput(parent);
46 			break;
47 		}
48 		dput(tdentry);
49 		tdentry = parent;
50 	}
51 	if (tdentry != exp->ex_path.dentry)
52 		dprintk("nfsd_acceptable failed at %p %pd\n", tdentry, tdentry);
53 	rv = (tdentry == exp->ex_path.dentry);
54 	dput(tdentry);
55 	return rv;
56 }
57 
58 /* Type check. The correct error return for type mismatches does not seem to be
59  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
60  * comment in the NFSv3 spec says this is incorrect (implementation notes for
61  * the write call).
62  */
63 static inline __be32
64 nfsd_mode_check(struct svc_rqst *rqstp, struct dentry *dentry,
65 		umode_t requested)
66 {
67 	umode_t mode = d_inode(dentry)->i_mode & S_IFMT;
68 
69 	if (requested == 0) /* the caller doesn't care */
70 		return nfs_ok;
71 	if (mode == requested) {
72 		if (mode == S_IFDIR && !d_can_lookup(dentry)) {
73 			WARN_ON_ONCE(1);
74 			return nfserr_notdir;
75 		}
76 		return nfs_ok;
77 	}
78 	/*
79 	 * v4 has an error more specific than err_notdir which we should
80 	 * return in preference to err_notdir:
81 	 */
82 	if (rqstp->rq_vers == 4 && mode == S_IFLNK)
83 		return nfserr_symlink;
84 	if (requested == S_IFDIR)
85 		return nfserr_notdir;
86 	if (mode == S_IFDIR)
87 		return nfserr_isdir;
88 	return nfserr_inval;
89 }
90 
91 static bool nfsd_originating_port_ok(struct svc_rqst *rqstp, int flags)
92 {
93 	if (flags & NFSEXP_INSECURE_PORT)
94 		return true;
95 	/* We don't require gss requests to use low ports: */
96 	if (rqstp->rq_cred.cr_flavor >= RPC_AUTH_GSS)
97 		return true;
98 	return test_bit(RQ_SECURE, &rqstp->rq_flags);
99 }
100 
101 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
102 					  struct svc_export *exp)
103 {
104 	int flags = nfsexp_flags(rqstp, exp);
105 
106 	/* Check if the request originated from a secure port. */
107 	if (!nfsd_originating_port_ok(rqstp, flags)) {
108 		RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
109 		dprintk("nfsd: request from insecure port %s!\n",
110 		        svc_print_addr(rqstp, buf, sizeof(buf)));
111 		return nfserr_perm;
112 	}
113 
114 	/* Set user creds for this exportpoint */
115 	return nfserrno(nfsd_setuser(rqstp, exp));
116 }
117 
118 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
119 	struct dentry *dentry, struct svc_export *exp)
120 {
121 	if (!(exp->ex_flags & NFSEXP_V4ROOT))
122 		return nfs_ok;
123 	/*
124 	 * v2/v3 clients have no need for the V4ROOT export--they use
125 	 * the mount protocl instead; also, further V4ROOT checks may be
126 	 * in v4-specific code, in which case v2/v3 clients could bypass
127 	 * them.
128 	 */
129 	if (!nfsd_v4client(rqstp))
130 		return nfserr_stale;
131 	/*
132 	 * We're exposing only the directories and symlinks that have to be
133 	 * traversed on the way to real exports:
134 	 */
135 	if (unlikely(!d_is_dir(dentry) &&
136 		     !d_is_symlink(dentry)))
137 		return nfserr_stale;
138 	/*
139 	 * A pseudoroot export gives permission to access only one
140 	 * single directory; the kernel has to make another upcall
141 	 * before granting access to anything else under it:
142 	 */
143 	if (unlikely(dentry != exp->ex_path.dentry))
144 		return nfserr_stale;
145 	return nfs_ok;
146 }
147 
148 /*
149  * Use the given filehandle to look up the corresponding export and
150  * dentry.  On success, the results are used to set fh_export and
151  * fh_dentry.
152  */
153 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
154 {
155 	struct knfsd_fh	*fh = &fhp->fh_handle;
156 	struct fid *fid = NULL, sfid;
157 	struct svc_export *exp;
158 	struct dentry *dentry;
159 	int fileid_type;
160 	int data_left = fh->fh_size/4;
161 	__be32 error;
162 
163 	error = nfserr_stale;
164 	if (rqstp->rq_vers > 2)
165 		error = nfserr_badhandle;
166 	if (rqstp->rq_vers == 4 && fh->fh_size == 0)
167 		return nfserr_nofilehandle;
168 
169 	if (fh->fh_version == 1) {
170 		int len;
171 
172 		if (--data_left < 0)
173 			return error;
174 		if (fh->fh_auth_type != 0)
175 			return error;
176 		len = key_len(fh->fh_fsid_type) / 4;
177 		if (len == 0)
178 			return error;
179 		if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
180 			/* deprecated, convert to type 3 */
181 			len = key_len(FSID_ENCODE_DEV)/4;
182 			fh->fh_fsid_type = FSID_ENCODE_DEV;
183 			/*
184 			 * struct knfsd_fh uses host-endian fields, which are
185 			 * sometimes used to hold net-endian values. This
186 			 * confuses sparse, so we must use __force here to
187 			 * keep it from complaining.
188 			 */
189 			fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
190 							ntohl((__force __be32)fh->fh_fsid[1])));
191 			fh->fh_fsid[1] = fh->fh_fsid[2];
192 		}
193 		data_left -= len;
194 		if (data_left < 0)
195 			return error;
196 		exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
197 		fid = (struct fid *)(fh->fh_fsid + len);
198 	} else {
199 		__u32 tfh[2];
200 		dev_t xdev;
201 		ino_t xino;
202 
203 		if (fh->fh_size != NFS_FHSIZE)
204 			return error;
205 		/* assume old filehandle format */
206 		xdev = old_decode_dev(fh->ofh_xdev);
207 		xino = u32_to_ino_t(fh->ofh_xino);
208 		mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
209 		exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
210 	}
211 
212 	error = nfserr_stale;
213 	if (IS_ERR(exp)) {
214 		trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
215 
216 		if (PTR_ERR(exp) == -ENOENT)
217 			return error;
218 
219 		return nfserrno(PTR_ERR(exp));
220 	}
221 
222 	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
223 		/* Elevate privileges so that the lack of 'r' or 'x'
224 		 * permission on some parent directory will
225 		 * not stop exportfs_decode_fh from being able
226 		 * to reconnect a directory into the dentry cache.
227 		 * The same problem can affect "SUBTREECHECK" exports,
228 		 * but as nfsd_acceptable depends on correct
229 		 * access control settings being in effect, we cannot
230 		 * fix that case easily.
231 		 */
232 		struct cred *new = prepare_creds();
233 		if (!new) {
234 			error =  nfserrno(-ENOMEM);
235 			goto out;
236 		}
237 		new->cap_effective =
238 			cap_raise_nfsd_set(new->cap_effective,
239 					   new->cap_permitted);
240 		put_cred(override_creds(new));
241 		put_cred(new);
242 	} else {
243 		error = nfsd_setuser_and_check_port(rqstp, exp);
244 		if (error)
245 			goto out;
246 	}
247 
248 	/*
249 	 * Look up the dentry using the NFS file handle.
250 	 */
251 	error = nfserr_stale;
252 	if (rqstp->rq_vers > 2)
253 		error = nfserr_badhandle;
254 
255 	if (fh->fh_version != 1) {
256 		sfid.i32.ino = fh->ofh_ino;
257 		sfid.i32.gen = fh->ofh_generation;
258 		sfid.i32.parent_ino = fh->ofh_dirino;
259 		fid = &sfid;
260 		data_left = 3;
261 		if (fh->ofh_dirino == 0)
262 			fileid_type = FILEID_INO32_GEN;
263 		else
264 			fileid_type = FILEID_INO32_GEN_PARENT;
265 	} else
266 		fileid_type = fh->fh_fileid_type;
267 
268 	if (fileid_type == FILEID_ROOT)
269 		dentry = dget(exp->ex_path.dentry);
270 	else {
271 		dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
272 				data_left, fileid_type,
273 				nfsd_acceptable, exp);
274 		if (IS_ERR_OR_NULL(dentry))
275 			trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
276 					dentry ?  PTR_ERR(dentry) : -ESTALE);
277 	}
278 	if (dentry == NULL)
279 		goto out;
280 	if (IS_ERR(dentry)) {
281 		if (PTR_ERR(dentry) != -EINVAL)
282 			error = nfserrno(PTR_ERR(dentry));
283 		goto out;
284 	}
285 
286 	if (d_is_dir(dentry) &&
287 			(dentry->d_flags & DCACHE_DISCONNECTED)) {
288 		printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
289 				dentry);
290 	}
291 
292 	fhp->fh_dentry = dentry;
293 	fhp->fh_export = exp;
294 	return 0;
295 out:
296 	exp_put(exp);
297 	return error;
298 }
299 
300 /**
301  * fh_verify - filehandle lookup and access checking
302  * @rqstp: pointer to current rpc request
303  * @fhp: filehandle to be verified
304  * @type: expected type of object pointed to by filehandle
305  * @access: type of access needed to object
306  *
307  * Look up a dentry from the on-the-wire filehandle, check the client's
308  * access to the export, and set the current task's credentials.
309  *
310  * Regardless of success or failure of fh_verify(), fh_put() should be
311  * called on @fhp when the caller is finished with the filehandle.
312  *
313  * fh_verify() may be called multiple times on a given filehandle, for
314  * example, when processing an NFSv4 compound.  The first call will look
315  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
316  * skip the lookup and just perform the other checks and possibly change
317  * the current task's credentials.
318  *
319  * @type specifies the type of object expected using one of the S_IF*
320  * constants defined in include/linux/stat.h.  The caller may use zero
321  * to indicate that it doesn't care, or a negative integer to indicate
322  * that it expects something not of the given type.
323  *
324  * @access is formed from the NFSD_MAY_* constants defined in
325  * fs/nfsd/vfs.h.
326  */
327 __be32
328 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
329 {
330 	struct svc_export *exp;
331 	struct dentry	*dentry;
332 	__be32		error;
333 
334 	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
335 
336 	if (!fhp->fh_dentry) {
337 		error = nfsd_set_fh_dentry(rqstp, fhp);
338 		if (error)
339 			goto out;
340 	}
341 	dentry = fhp->fh_dentry;
342 	exp = fhp->fh_export;
343 	/*
344 	 * We still have to do all these permission checks, even when
345 	 * fh_dentry is already set:
346 	 * 	- fh_verify may be called multiple times with different
347 	 * 	  "access" arguments (e.g. nfsd_proc_create calls
348 	 * 	  fh_verify(...,NFSD_MAY_EXEC) first, then later (in
349 	 * 	  nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
350 	 *	- in the NFSv4 case, the filehandle may have been filled
351 	 *	  in by fh_compose, and given a dentry, but further
352 	 *	  compound operations performed with that filehandle
353 	 *	  still need permissions checks.  In the worst case, a
354 	 *	  mountpoint crossing may have changed the export
355 	 *	  options, and we may now need to use a different uid
356 	 *	  (for example, if different id-squashing options are in
357 	 *	  effect on the new filesystem).
358 	 */
359 	error = check_pseudo_root(rqstp, dentry, exp);
360 	if (error)
361 		goto out;
362 
363 	error = nfsd_setuser_and_check_port(rqstp, exp);
364 	if (error)
365 		goto out;
366 
367 	error = nfsd_mode_check(rqstp, dentry, type);
368 	if (error)
369 		goto out;
370 
371 	/*
372 	 * pseudoflavor restrictions are not enforced on NLM,
373 	 * which clients virtually always use auth_sys for,
374 	 * even while using RPCSEC_GSS for NFS.
375 	 */
376 	if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
377 		goto skip_pseudoflavor_check;
378 	/*
379 	 * Clients may expect to be able to use auth_sys during mount,
380 	 * even if they use gss for everything else; see section 2.3.2
381 	 * of rfc 2623.
382 	 */
383 	if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
384 			&& exp->ex_path.dentry == dentry)
385 		goto skip_pseudoflavor_check;
386 
387 	error = check_nfsd_access(exp, rqstp);
388 	if (error)
389 		goto out;
390 
391 skip_pseudoflavor_check:
392 	/* Finally, check access permissions. */
393 	error = nfsd_permission(rqstp, exp, dentry, access);
394 
395 	if (error) {
396 		dprintk("fh_verify: %pd2 permission failure, "
397 			"acc=%x, error=%d\n",
398 			dentry,
399 			access, ntohl(error));
400 	}
401 out:
402 	if (error == nfserr_stale)
403 		nfsdstats.fh_stale++;
404 	return error;
405 }
406 
407 
408 /*
409  * Compose a file handle for an NFS reply.
410  *
411  * Note that when first composed, the dentry may not yet have
412  * an inode.  In this case a call to fh_update should be made
413  * before the fh goes out on the wire ...
414  */
415 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
416 		struct dentry *dentry)
417 {
418 	if (dentry != exp->ex_path.dentry) {
419 		struct fid *fid = (struct fid *)
420 			(fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
421 		int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
422 		int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
423 
424 		fhp->fh_handle.fh_fileid_type =
425 			exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
426 		fhp->fh_handle.fh_size += maxsize * 4;
427 	} else {
428 		fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
429 	}
430 }
431 
432 /*
433  * for composing old style file handles
434  */
435 static inline void _fh_update_old(struct dentry *dentry,
436 				  struct svc_export *exp,
437 				  struct knfsd_fh *fh)
438 {
439 	fh->ofh_ino = ino_t_to_u32(d_inode(dentry)->i_ino);
440 	fh->ofh_generation = d_inode(dentry)->i_generation;
441 	if (d_is_dir(dentry) ||
442 	    (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
443 		fh->ofh_dirino = 0;
444 }
445 
446 static bool is_root_export(struct svc_export *exp)
447 {
448 	return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
449 }
450 
451 static struct super_block *exp_sb(struct svc_export *exp)
452 {
453 	return exp->ex_path.dentry->d_sb;
454 }
455 
456 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
457 {
458 	switch (fsid_type) {
459 	case FSID_DEV:
460 		if (!old_valid_dev(exp_sb(exp)->s_dev))
461 			return false;
462 		fallthrough;
463 	case FSID_MAJOR_MINOR:
464 	case FSID_ENCODE_DEV:
465 		return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
466 	case FSID_NUM:
467 		return exp->ex_flags & NFSEXP_FSID;
468 	case FSID_UUID8:
469 	case FSID_UUID16:
470 		if (!is_root_export(exp))
471 			return false;
472 		fallthrough;
473 	case FSID_UUID4_INUM:
474 	case FSID_UUID16_INUM:
475 		return exp->ex_uuid != NULL;
476 	}
477 	return true;
478 }
479 
480 
481 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
482 {
483 	u8 version;
484 	u8 fsid_type;
485 retry:
486 	version = 1;
487 	if (ref_fh && ref_fh->fh_export == exp) {
488 		version = ref_fh->fh_handle.fh_version;
489 		fsid_type = ref_fh->fh_handle.fh_fsid_type;
490 
491 		ref_fh = NULL;
492 
493 		switch (version) {
494 		case 0xca:
495 			fsid_type = FSID_DEV;
496 			break;
497 		case 1:
498 			break;
499 		default:
500 			goto retry;
501 		}
502 
503 		/*
504 		 * As the fsid -> filesystem mapping was guided by
505 		 * user-space, there is no guarantee that the filesystem
506 		 * actually supports that fsid type. If it doesn't we
507 		 * loop around again without ref_fh set.
508 		 */
509 		if (!fsid_type_ok_for_exp(fsid_type, exp))
510 			goto retry;
511 	} else if (exp->ex_flags & NFSEXP_FSID) {
512 		fsid_type = FSID_NUM;
513 	} else if (exp->ex_uuid) {
514 		if (fhp->fh_maxsize >= 64) {
515 			if (is_root_export(exp))
516 				fsid_type = FSID_UUID16;
517 			else
518 				fsid_type = FSID_UUID16_INUM;
519 		} else {
520 			if (is_root_export(exp))
521 				fsid_type = FSID_UUID8;
522 			else
523 				fsid_type = FSID_UUID4_INUM;
524 		}
525 	} else if (!old_valid_dev(exp_sb(exp)->s_dev))
526 		/* for newer device numbers, we must use a newer fsid format */
527 		fsid_type = FSID_ENCODE_DEV;
528 	else
529 		fsid_type = FSID_DEV;
530 	fhp->fh_handle.fh_version = version;
531 	if (version)
532 		fhp->fh_handle.fh_fsid_type = fsid_type;
533 }
534 
535 __be32
536 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
537 	   struct svc_fh *ref_fh)
538 {
539 	/* ref_fh is a reference file handle.
540 	 * if it is non-null and for the same filesystem, then we should compose
541 	 * a filehandle which is of the same version, where possible.
542 	 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
543 	 * Then create a 32byte filehandle using nfs_fhbase_old
544 	 *
545 	 */
546 
547 	struct inode * inode = d_inode(dentry);
548 	dev_t ex_dev = exp_sb(exp)->s_dev;
549 
550 	dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
551 		MAJOR(ex_dev), MINOR(ex_dev),
552 		(long) d_inode(exp->ex_path.dentry)->i_ino,
553 		dentry,
554 		(inode ? inode->i_ino : 0));
555 
556 	/* Choose filehandle version and fsid type based on
557 	 * the reference filehandle (if it is in the same export)
558 	 * or the export options.
559 	 */
560 	set_version_and_fsid_type(fhp, exp, ref_fh);
561 
562 	if (ref_fh == fhp)
563 		fh_put(ref_fh);
564 
565 	if (fhp->fh_locked || fhp->fh_dentry) {
566 		printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
567 		       dentry);
568 	}
569 	if (fhp->fh_maxsize < NFS_FHSIZE)
570 		printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
571 		       fhp->fh_maxsize,
572 		       dentry);
573 
574 	fhp->fh_dentry = dget(dentry); /* our internal copy */
575 	fhp->fh_export = exp_get(exp);
576 
577 	if (fhp->fh_handle.fh_version == 0xca) {
578 		/* old style filehandle please */
579 		memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
580 		fhp->fh_handle.fh_size = NFS_FHSIZE;
581 		fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
582 		fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
583 		fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
584 		fhp->fh_handle.ofh_xino =
585 			ino_t_to_u32(d_inode(exp->ex_path.dentry)->i_ino);
586 		fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
587 		if (inode)
588 			_fh_update_old(dentry, exp, &fhp->fh_handle);
589 	} else {
590 		fhp->fh_handle.fh_size =
591 			key_len(fhp->fh_handle.fh_fsid_type) + 4;
592 		fhp->fh_handle.fh_auth_type = 0;
593 
594 		mk_fsid(fhp->fh_handle.fh_fsid_type,
595 			fhp->fh_handle.fh_fsid,
596 			ex_dev,
597 			d_inode(exp->ex_path.dentry)->i_ino,
598 			exp->ex_fsid, exp->ex_uuid);
599 
600 		if (inode)
601 			_fh_update(fhp, exp, dentry);
602 		if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
603 			fh_put(fhp);
604 			return nfserr_opnotsupp;
605 		}
606 	}
607 
608 	return 0;
609 }
610 
611 /*
612  * Update file handle information after changing a dentry.
613  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
614  */
615 __be32
616 fh_update(struct svc_fh *fhp)
617 {
618 	struct dentry *dentry;
619 
620 	if (!fhp->fh_dentry)
621 		goto out_bad;
622 
623 	dentry = fhp->fh_dentry;
624 	if (d_really_is_negative(dentry))
625 		goto out_negative;
626 	if (fhp->fh_handle.fh_version != 1) {
627 		_fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
628 	} else {
629 		if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
630 			return 0;
631 
632 		_fh_update(fhp, fhp->fh_export, dentry);
633 		if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
634 			return nfserr_opnotsupp;
635 	}
636 	return 0;
637 out_bad:
638 	printk(KERN_ERR "fh_update: fh not verified!\n");
639 	return nfserr_serverfault;
640 out_negative:
641 	printk(KERN_ERR "fh_update: %pd2 still negative!\n",
642 		dentry);
643 	return nfserr_serverfault;
644 }
645 
646 /*
647  * Release a file handle.
648  */
649 void
650 fh_put(struct svc_fh *fhp)
651 {
652 	struct dentry * dentry = fhp->fh_dentry;
653 	struct svc_export * exp = fhp->fh_export;
654 	if (dentry) {
655 		fh_unlock(fhp);
656 		fhp->fh_dentry = NULL;
657 		dput(dentry);
658 		fh_clear_wcc(fhp);
659 	}
660 	fh_drop_write(fhp);
661 	if (exp) {
662 		exp_put(exp);
663 		fhp->fh_export = NULL;
664 	}
665 	return;
666 }
667 
668 /*
669  * Shorthand for dprintk()'s
670  */
671 char * SVCFH_fmt(struct svc_fh *fhp)
672 {
673 	struct knfsd_fh *fh = &fhp->fh_handle;
674 
675 	static char buf[80];
676 	sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
677 		fh->fh_size,
678 		fh->fh_base.fh_pad[0],
679 		fh->fh_base.fh_pad[1],
680 		fh->fh_base.fh_pad[2],
681 		fh->fh_base.fh_pad[3],
682 		fh->fh_base.fh_pad[4],
683 		fh->fh_base.fh_pad[5]);
684 	return buf;
685 }
686 
687 enum fsid_source fsid_source(struct svc_fh *fhp)
688 {
689 	if (fhp->fh_handle.fh_version != 1)
690 		return FSIDSOURCE_DEV;
691 	switch(fhp->fh_handle.fh_fsid_type) {
692 	case FSID_DEV:
693 	case FSID_ENCODE_DEV:
694 	case FSID_MAJOR_MINOR:
695 		if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
696 			return FSIDSOURCE_DEV;
697 		break;
698 	case FSID_NUM:
699 		if (fhp->fh_export->ex_flags & NFSEXP_FSID)
700 			return FSIDSOURCE_FSID;
701 		break;
702 	default:
703 		break;
704 	}
705 	/* either a UUID type filehandle, or the filehandle doesn't
706 	 * match the export.
707 	 */
708 	if (fhp->fh_export->ex_flags & NFSEXP_FSID)
709 		return FSIDSOURCE_FSID;
710 	if (fhp->fh_export->ex_uuid)
711 		return FSIDSOURCE_UUID;
712 	return FSIDSOURCE_DEV;
713 }
714