Root/fs/nfsd/nfsfh.c

1/*
2 * NFS server file handle treatment.
3 *
4 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
5 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
6 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
7 * ... and again Southern-Winter 2001 to support export_operations
8 */
9
10#include <linux/exportfs.h>
11
12#include <linux/sunrpc/svcauth_gss.h>
13#include "nfsd.h"
14#include "vfs.h"
15#include "auth.h"
16
17#define NFSDDBG_FACILITY NFSDDBG_FH
18
19
20/*
21 * our acceptability function.
22 * if NOSUBTREECHECK, accept anything
23 * if not, require that we can walk up to exp->ex_dentry
24 * doing some checks on the 'x' bits
25 */
26static int nfsd_acceptable(void *expv, struct dentry *dentry)
27{
28    struct svc_export *exp = expv;
29    int rv;
30    struct dentry *tdentry;
31    struct dentry *parent;
32
33    if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
34        return 1;
35
36    tdentry = dget(dentry);
37    while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
38        /* make sure parents give x permission to user */
39        int err;
40        parent = dget_parent(tdentry);
41        err = inode_permission(parent->d_inode, MAY_EXEC);
42        if (err < 0) {
43            dput(parent);
44            break;
45        }
46        dput(tdentry);
47        tdentry = parent;
48    }
49    if (tdentry != exp->ex_path.dentry)
50        dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
51    rv = (tdentry == exp->ex_path.dentry);
52    dput(tdentry);
53    return rv;
54}
55
56/* Type check. The correct error return for type mismatches does not seem to be
57 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
58 * comment in the NFSv3 spec says this is incorrect (implementation notes for
59 * the write call).
60 */
61static inline __be32
62nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
63{
64    /* Type can be negative when creating hardlinks - not to a dir */
65    if (type > 0 && (mode & S_IFMT) != type) {
66        if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
67            return nfserr_symlink;
68        else if (type == S_IFDIR)
69            return nfserr_notdir;
70        else if ((mode & S_IFMT) == S_IFDIR)
71            return nfserr_isdir;
72        else
73            return nfserr_inval;
74    }
75    if (type < 0 && (mode & S_IFMT) == -type) {
76        if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
77            return nfserr_symlink;
78        else if (type == -S_IFDIR)
79            return nfserr_isdir;
80        else
81            return nfserr_notdir;
82    }
83    return 0;
84}
85
86static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
87                      struct svc_export *exp)
88{
89    int flags = nfsexp_flags(rqstp, exp);
90
91    /* Check if the request originated from a secure port. */
92    if (!rqstp->rq_secure && !(flags & NFSEXP_INSECURE_PORT)) {
93        RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
94        dprintk(KERN_WARNING
95               "nfsd: request from insecure port %s!\n",
96               svc_print_addr(rqstp, buf, sizeof(buf)));
97        return nfserr_perm;
98    }
99
100    /* Set user creds for this exportpoint */
101    return nfserrno(nfsd_setuser(rqstp, exp));
102}
103
104static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
105    struct dentry *dentry, struct svc_export *exp)
106{
107    if (!(exp->ex_flags & NFSEXP_V4ROOT))
108        return nfs_ok;
109    /*
110     * v2/v3 clients have no need for the V4ROOT export--they use
111     * the mount protocl instead; also, further V4ROOT checks may be
112     * in v4-specific code, in which case v2/v3 clients could bypass
113     * them.
114     */
115    if (!nfsd_v4client(rqstp))
116        return nfserr_stale;
117    /*
118     * We're exposing only the directories and symlinks that have to be
119     * traversed on the way to real exports:
120     */
121    if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
122             !S_ISLNK(dentry->d_inode->i_mode)))
123        return nfserr_stale;
124    /*
125     * A pseudoroot export gives permission to access only one
126     * single directory; the kernel has to make another upcall
127     * before granting access to anything else under it:
128     */
129    if (unlikely(dentry != exp->ex_path.dentry))
130        return nfserr_stale;
131    return nfs_ok;
132}
133
134/*
135 * Use the given filehandle to look up the corresponding export and
136 * dentry. On success, the results are used to set fh_export and
137 * fh_dentry.
138 */
139static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
140{
141    struct knfsd_fh *fh = &fhp->fh_handle;
142    struct fid *fid = NULL, sfid;
143    struct svc_export *exp;
144    struct dentry *dentry;
145    int fileid_type;
146    int data_left = fh->fh_size/4;
147    __be32 error;
148
149    error = nfserr_stale;
150    if (rqstp->rq_vers > 2)
151        error = nfserr_badhandle;
152    if (rqstp->rq_vers == 4 && fh->fh_size == 0)
153        return nfserr_nofilehandle;
154
155    if (fh->fh_version == 1) {
156        int len;
157
158        if (--data_left < 0)
159            return error;
160        if (fh->fh_auth_type != 0)
161            return error;
162        len = key_len(fh->fh_fsid_type) / 4;
163        if (len == 0)
164            return error;
165        if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
166            /* deprecated, convert to type 3 */
167            len = key_len(FSID_ENCODE_DEV)/4;
168            fh->fh_fsid_type = FSID_ENCODE_DEV;
169            fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
170            fh->fh_fsid[1] = fh->fh_fsid[2];
171        }
172        data_left -= len;
173        if (data_left < 0)
174            return error;
175        exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
176        fid = (struct fid *)(fh->fh_auth + len);
177    } else {
178        __u32 tfh[2];
179        dev_t xdev;
180        ino_t xino;
181
182        if (fh->fh_size != NFS_FHSIZE)
183            return error;
184        /* assume old filehandle format */
185        xdev = old_decode_dev(fh->ofh_xdev);
186        xino = u32_to_ino_t(fh->ofh_xino);
187        mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
188        exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
189    }
190
191    error = nfserr_stale;
192    if (PTR_ERR(exp) == -ENOENT)
193        return error;
194
195    if (IS_ERR(exp))
196        return nfserrno(PTR_ERR(exp));
197
198    if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
199        /* Elevate privileges so that the lack of 'r' or 'x'
200         * permission on some parent directory will
201         * not stop exportfs_decode_fh from being able
202         * to reconnect a directory into the dentry cache.
203         * The same problem can affect "SUBTREECHECK" exports,
204         * but as nfsd_acceptable depends on correct
205         * access control settings being in effect, we cannot
206         * fix that case easily.
207         */
208        struct cred *new = prepare_creds();
209        if (!new)
210            return nfserrno(-ENOMEM);
211        new->cap_effective =
212            cap_raise_nfsd_set(new->cap_effective,
213                       new->cap_permitted);
214        put_cred(override_creds(new));
215        put_cred(new);
216    } else {
217        error = nfsd_setuser_and_check_port(rqstp, exp);
218        if (error)
219            goto out;
220    }
221
222    /*
223     * Look up the dentry using the NFS file handle.
224     */
225    error = nfserr_stale;
226    if (rqstp->rq_vers > 2)
227        error = nfserr_badhandle;
228
229    if (fh->fh_version != 1) {
230        sfid.i32.ino = fh->ofh_ino;
231        sfid.i32.gen = fh->ofh_generation;
232        sfid.i32.parent_ino = fh->ofh_dirino;
233        fid = &sfid;
234        data_left = 3;
235        if (fh->ofh_dirino == 0)
236            fileid_type = FILEID_INO32_GEN;
237        else
238            fileid_type = FILEID_INO32_GEN_PARENT;
239    } else
240        fileid_type = fh->fh_fileid_type;
241
242    if (fileid_type == FILEID_ROOT)
243        dentry = dget(exp->ex_path.dentry);
244    else {
245        dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
246                data_left, fileid_type,
247                nfsd_acceptable, exp);
248    }
249    if (dentry == NULL)
250        goto out;
251    if (IS_ERR(dentry)) {
252        if (PTR_ERR(dentry) != -EINVAL)
253            error = nfserrno(PTR_ERR(dentry));
254        goto out;
255    }
256
257    if (S_ISDIR(dentry->d_inode->i_mode) &&
258            (dentry->d_flags & DCACHE_DISCONNECTED)) {
259        printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
260                dentry->d_parent->d_name.name, dentry->d_name.name);
261    }
262
263    fhp->fh_dentry = dentry;
264    fhp->fh_export = exp;
265    return 0;
266out:
267    exp_put(exp);
268    return error;
269}
270
271/**
272 * fh_verify - filehandle lookup and access checking
273 * @rqstp: pointer to current rpc request
274 * @fhp: filehandle to be verified
275 * @type: expected type of object pointed to by filehandle
276 * @access: type of access needed to object
277 *
278 * Look up a dentry from the on-the-wire filehandle, check the client's
279 * access to the export, and set the current task's credentials.
280 *
281 * Regardless of success or failure of fh_verify(), fh_put() should be
282 * called on @fhp when the caller is finished with the filehandle.
283 *
284 * fh_verify() may be called multiple times on a given filehandle, for
285 * example, when processing an NFSv4 compound. The first call will look
286 * up a dentry using the on-the-wire filehandle. Subsequent calls will
287 * skip the lookup and just perform the other checks and possibly change
288 * the current task's credentials.
289 *
290 * @type specifies the type of object expected using one of the S_IF*
291 * constants defined in include/linux/stat.h. The caller may use zero
292 * to indicate that it doesn't care, or a negative integer to indicate
293 * that it expects something not of the given type.
294 *
295 * @access is formed from the NFSD_MAY_* constants defined in
296 * include/linux/nfsd/nfsd.h.
297 */
298__be32
299fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
300{
301    struct svc_export *exp;
302    struct dentry *dentry;
303    __be32 error;
304
305    dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
306
307    if (!fhp->fh_dentry) {
308        error = nfsd_set_fh_dentry(rqstp, fhp);
309        if (error)
310            goto out;
311    }
312    dentry = fhp->fh_dentry;
313    exp = fhp->fh_export;
314    /*
315     * We still have to do all these permission checks, even when
316     * fh_dentry is already set:
317     * - fh_verify may be called multiple times with different
318     * "access" arguments (e.g. nfsd_proc_create calls
319     * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
320     * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
321     * - in the NFSv4 case, the filehandle may have been filled
322     * in by fh_compose, and given a dentry, but further
323     * compound operations performed with that filehandle
324     * still need permissions checks. In the worst case, a
325     * mountpoint crossing may have changed the export
326     * options, and we may now need to use a different uid
327     * (for example, if different id-squashing options are in
328     * effect on the new filesystem).
329     */
330    error = check_pseudo_root(rqstp, dentry, exp);
331    if (error)
332        goto out;
333
334    error = nfsd_setuser_and_check_port(rqstp, exp);
335    if (error)
336        goto out;
337
338    error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
339    if (error)
340        goto out;
341
342    /*
343     * pseudoflavor restrictions are not enforced on NLM,
344     * which clients virtually always use auth_sys for,
345     * even while using RPCSEC_GSS for NFS.
346     */
347    if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
348        goto skip_pseudoflavor_check;
349    /*
350     * Clients may expect to be able to use auth_sys during mount,
351     * even if they use gss for everything else; see section 2.3.2
352     * of rfc 2623.
353     */
354    if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
355            && exp->ex_path.dentry == dentry)
356        goto skip_pseudoflavor_check;
357
358    error = check_nfsd_access(exp, rqstp);
359    if (error)
360        goto out;
361
362skip_pseudoflavor_check:
363    /* Finally, check access permissions. */
364    error = nfsd_permission(rqstp, exp, dentry, access);
365
366    if (error) {
367        dprintk("fh_verify: %s/%s permission failure, "
368            "acc=%x, error=%d\n",
369            dentry->d_parent->d_name.name,
370            dentry->d_name.name,
371            access, ntohl(error));
372    }
373out:
374    if (error == nfserr_stale)
375        nfsdstats.fh_stale++;
376    return error;
377}
378
379
380/*
381 * Compose a file handle for an NFS reply.
382 *
383 * Note that when first composed, the dentry may not yet have
384 * an inode. In this case a call to fh_update should be made
385 * before the fh goes out on the wire ...
386 */
387static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
388        struct dentry *dentry)
389{
390    if (dentry != exp->ex_path.dentry) {
391        struct fid *fid = (struct fid *)
392            (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
393        int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
394        int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
395
396        fhp->fh_handle.fh_fileid_type =
397            exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
398        fhp->fh_handle.fh_size += maxsize * 4;
399    } else {
400        fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
401    }
402}
403
404/*
405 * for composing old style file handles
406 */
407static inline void _fh_update_old(struct dentry *dentry,
408                  struct svc_export *exp,
409                  struct knfsd_fh *fh)
410{
411    fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
412    fh->ofh_generation = dentry->d_inode->i_generation;
413    if (S_ISDIR(dentry->d_inode->i_mode) ||
414        (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
415        fh->ofh_dirino = 0;
416}
417
418static bool is_root_export(struct svc_export *exp)
419{
420    return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
421}
422
423static struct super_block *exp_sb(struct svc_export *exp)
424{
425    return exp->ex_path.dentry->d_inode->i_sb;
426}
427
428static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
429{
430    switch (fsid_type) {
431    case FSID_DEV:
432        if (!old_valid_dev(exp_sb(exp)->s_dev))
433            return 0;
434        /* FALL THROUGH */
435    case FSID_MAJOR_MINOR:
436    case FSID_ENCODE_DEV:
437        return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
438    case FSID_NUM:
439        return exp->ex_flags & NFSEXP_FSID;
440    case FSID_UUID8:
441    case FSID_UUID16:
442        if (!is_root_export(exp))
443            return 0;
444        /* fall through */
445    case FSID_UUID4_INUM:
446    case FSID_UUID16_INUM:
447        return exp->ex_uuid != NULL;
448    }
449    return 1;
450}
451
452
453static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
454{
455    u8 version;
456    u8 fsid_type;
457retry:
458    version = 1;
459    if (ref_fh && ref_fh->fh_export == exp) {
460        version = ref_fh->fh_handle.fh_version;
461        fsid_type = ref_fh->fh_handle.fh_fsid_type;
462
463        ref_fh = NULL;
464
465        switch (version) {
466        case 0xca:
467            fsid_type = FSID_DEV;
468            break;
469        case 1:
470            break;
471        default:
472            goto retry;
473        }
474
475        /*
476         * As the fsid -> filesystem mapping was guided by
477         * user-space, there is no guarantee that the filesystem
478         * actually supports that fsid type. If it doesn't we
479         * loop around again without ref_fh set.
480         */
481        if (!fsid_type_ok_for_exp(fsid_type, exp))
482            goto retry;
483    } else if (exp->ex_flags & NFSEXP_FSID) {
484        fsid_type = FSID_NUM;
485    } else if (exp->ex_uuid) {
486        if (fhp->fh_maxsize >= 64) {
487            if (is_root_export(exp))
488                fsid_type = FSID_UUID16;
489            else
490                fsid_type = FSID_UUID16_INUM;
491        } else {
492            if (is_root_export(exp))
493                fsid_type = FSID_UUID8;
494            else
495                fsid_type = FSID_UUID4_INUM;
496        }
497    } else if (!old_valid_dev(exp_sb(exp)->s_dev))
498        /* for newer device numbers, we must use a newer fsid format */
499        fsid_type = FSID_ENCODE_DEV;
500    else
501        fsid_type = FSID_DEV;
502    fhp->fh_handle.fh_version = version;
503    if (version)
504        fhp->fh_handle.fh_fsid_type = fsid_type;
505}
506
507__be32
508fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
509       struct svc_fh *ref_fh)
510{
511    /* ref_fh is a reference file handle.
512     * if it is non-null and for the same filesystem, then we should compose
513     * a filehandle which is of the same version, where possible.
514     * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
515     * Then create a 32byte filehandle using nfs_fhbase_old
516     *
517     */
518
519    struct inode * inode = dentry->d_inode;
520    struct dentry *parent = dentry->d_parent;
521    __u32 *datap;
522    dev_t ex_dev = exp_sb(exp)->s_dev;
523
524    dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
525        MAJOR(ex_dev), MINOR(ex_dev),
526        (long) exp->ex_path.dentry->d_inode->i_ino,
527        parent->d_name.name, dentry->d_name.name,
528        (inode ? inode->i_ino : 0));
529
530    /* Choose filehandle version and fsid type based on
531     * the reference filehandle (if it is in the same export)
532     * or the export options.
533     */
534     set_version_and_fsid_type(fhp, exp, ref_fh);
535
536    if (ref_fh == fhp)
537        fh_put(ref_fh);
538
539    if (fhp->fh_locked || fhp->fh_dentry) {
540        printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
541               parent->d_name.name, dentry->d_name.name);
542    }
543    if (fhp->fh_maxsize < NFS_FHSIZE)
544        printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
545               fhp->fh_maxsize,
546               parent->d_name.name, dentry->d_name.name);
547
548    fhp->fh_dentry = dget(dentry); /* our internal copy */
549    fhp->fh_export = exp;
550    cache_get(&exp->h);
551
552    if (fhp->fh_handle.fh_version == 0xca) {
553        /* old style filehandle please */
554        memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
555        fhp->fh_handle.fh_size = NFS_FHSIZE;
556        fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
557        fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
558        fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
559        fhp->fh_handle.ofh_xino =
560            ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
561        fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
562        if (inode)
563            _fh_update_old(dentry, exp, &fhp->fh_handle);
564    } else {
565        int len;
566        fhp->fh_handle.fh_auth_type = 0;
567        datap = fhp->fh_handle.fh_auth+0;
568        mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
569            exp->ex_path.dentry->d_inode->i_ino,
570            exp->ex_fsid, exp->ex_uuid);
571
572        len = key_len(fhp->fh_handle.fh_fsid_type);
573        datap += len/4;
574        fhp->fh_handle.fh_size = 4 + len;
575
576        if (inode)
577            _fh_update(fhp, exp, dentry);
578        if (fhp->fh_handle.fh_fileid_type == 255) {
579            fh_put(fhp);
580            return nfserr_opnotsupp;
581        }
582    }
583
584    return 0;
585}
586
587/*
588 * Update file handle information after changing a dentry.
589 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
590 */
591__be32
592fh_update(struct svc_fh *fhp)
593{
594    struct dentry *dentry;
595
596    if (!fhp->fh_dentry)
597        goto out_bad;
598
599    dentry = fhp->fh_dentry;
600    if (!dentry->d_inode)
601        goto out_negative;
602    if (fhp->fh_handle.fh_version != 1) {
603        _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
604    } else {
605        if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
606            goto out;
607
608        _fh_update(fhp, fhp->fh_export, dentry);
609        if (fhp->fh_handle.fh_fileid_type == 255)
610            return nfserr_opnotsupp;
611    }
612out:
613    return 0;
614
615out_bad:
616    printk(KERN_ERR "fh_update: fh not verified!\n");
617    goto out;
618out_negative:
619    printk(KERN_ERR "fh_update: %s/%s still negative!\n",
620        dentry->d_parent->d_name.name, dentry->d_name.name);
621    goto out;
622}
623
624/*
625 * Release a file handle.
626 */
627void
628fh_put(struct svc_fh *fhp)
629{
630    struct dentry * dentry = fhp->fh_dentry;
631    struct svc_export * exp = fhp->fh_export;
632    if (dentry) {
633        fh_unlock(fhp);
634        fhp->fh_dentry = NULL;
635        dput(dentry);
636#ifdef CONFIG_NFSD_V3
637        fhp->fh_pre_saved = 0;
638        fhp->fh_post_saved = 0;
639#endif
640    }
641    if (exp) {
642        cache_put(&exp->h, &svc_export_cache);
643        fhp->fh_export = NULL;
644    }
645    return;
646}
647
648/*
649 * Shorthand for dprintk()'s
650 */
651char * SVCFH_fmt(struct svc_fh *fhp)
652{
653    struct knfsd_fh *fh = &fhp->fh_handle;
654
655    static char buf[80];
656    sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
657        fh->fh_size,
658        fh->fh_base.fh_pad[0],
659        fh->fh_base.fh_pad[1],
660        fh->fh_base.fh_pad[2],
661        fh->fh_base.fh_pad[3],
662        fh->fh_base.fh_pad[4],
663        fh->fh_base.fh_pad[5]);
664    return buf;
665}
666
667enum fsid_source fsid_source(struct svc_fh *fhp)
668{
669    if (fhp->fh_handle.fh_version != 1)
670        return FSIDSOURCE_DEV;
671    switch(fhp->fh_handle.fh_fsid_type) {
672    case FSID_DEV:
673    case FSID_ENCODE_DEV:
674    case FSID_MAJOR_MINOR:
675        if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
676            return FSIDSOURCE_DEV;
677        break;
678    case FSID_NUM:
679        if (fhp->fh_export->ex_flags & NFSEXP_FSID)
680            return FSIDSOURCE_FSID;
681        break;
682    default:
683        break;
684    }
685    /* either a UUID type filehandle, or the filehandle doesn't
686     * match the export.
687     */
688    if (fhp->fh_export->ex_flags & NFSEXP_FSID)
689        return FSIDSOURCE_FSID;
690    if (fhp->fh_export->ex_uuid)
691        return FSIDSOURCE_UUID;
692    return FSIDSOURCE_DEV;
693}
694

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