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   1 /*
   2  * linux/fs/nfsd/nfsfh.c
   3  *
   4  * NFS server file handle treatment.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
   8  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
   9  * ... and again Southern-Winter 2001 to support export_operations
  10  */
  11
  12 #include <linux/slab.h>
  13 #include <linux/fs.h>
  14 #include <linux/unistd.h>
  15 #include <linux/string.h>
  16 #include <linux/stat.h>
  17 #include <linux/dcache.h>
  18 #include <linux/exportfs.h>
  19 #include <linux/mount.h>
  20
  21 #include <linux/sunrpc/clnt.h>
  22 #include <linux/sunrpc/svc.h>
  23 #include <linux/sunrpc/svcauth_gss.h>
  24 #include <linux/nfsd/nfsd.h>
  25 #include "auth.h"
  26
  27 #define NFSDDBG_FACILITY                NFSDDBG_FH
  28
  29
  30 static int nfsd_nr_verified;
  31 static int nfsd_nr_put;
  32
  33 /*
  34  * our acceptability function.
  35  * if NOSUBTREECHECK, accept anything
  36  * if not, require that we can walk up to exp->ex_dentry
  37  * doing some checks on the 'x' bits
  38  */
  39 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  40 {
  41         struct svc_export *exp = expv;
  42         int rv;
  43         struct dentry *tdentry;
  44         struct dentry *parent;
  45
  46         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  47                 return 1;
  48
  49         tdentry = dget(dentry);
  50         while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
  51                 /* make sure parents give x permission to user */
  52                 int err;
  53                 parent = dget_parent(tdentry);
  54                 err = inode_permission(parent->d_inode, MAY_EXEC);
  55                 if (err < 0) {
  56                         dput(parent);
  57                         break;
  58                 }
  59                 dput(tdentry);
  60                 tdentry = parent;
  61         }
  62         if (tdentry != exp->ex_path.dentry)
  63                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  64         rv = (tdentry == exp->ex_path.dentry);
  65         dput(tdentry);
  66         return rv;
  67 }
  68
  69 /* Type check. The correct error return for type mismatches does not seem to be
  70  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  71  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  72  * the write call).
  73  */
  74 static inline __be32
  75 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  76 {
  77         /* Type can be negative when creating hardlinks - not to a dir */
  78         if (type > 0 && (mode & S_IFMT) != type) {
  79                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  80                         return nfserr_symlink;
  81                 else if (type == S_IFDIR)
  82                         return nfserr_notdir;
  83                 else if ((mode & S_IFMT) == S_IFDIR)
  84                         return nfserr_isdir;
  85                 else
  86                         return nfserr_inval;
  87         }
  88         if (type < 0 && (mode & S_IFMT) == -type) {
  89                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  90                         return nfserr_symlink;
  91                 else if (type == -S_IFDIR)
  92                         return nfserr_isdir;
  93                 else
  94                         return nfserr_notdir;
  95         }
  96         return 0;
  97 }
  98
  99 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 100                                           struct svc_export *exp)
 101 {
 102         /* Check if the request originated from a secure port. */
 103         if (!rqstp->rq_secure && EX_SECURE(exp)) {
 104                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 105                 dprintk(KERN_WARNING
 106                        "nfsd: request from insecure port %s!\n",
 107                        svc_print_addr(rqstp, buf, sizeof(buf)));
 108                 return nfserr_perm;
 109         }
 110
 111         /* Set user creds for this exportpoint */
 112         return nfserrno(nfsd_setuser(rqstp, exp));
 113 }
 114
 115 /*
 116  * Use the given filehandle to look up the corresponding export and
 117  * dentry.  On success, the results are used to set fh_export and
 118  * fh_dentry.
 119  */
 120 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 121 {
 122         struct knfsd_fh *fh = &fhp->fh_handle;
 123         struct fid *fid = NULL, sfid;
 124         struct svc_export *exp;
 125         struct dentry *dentry;
 126         int fileid_type;
 127         int data_left = fh->fh_size/4;
 128         __be32 error;
 129
 130         error = nfserr_stale;
 131         if (rqstp->rq_vers > 2)
 132                 error = nfserr_badhandle;
 133         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 134                 return nfserr_nofilehandle;
 135
 136         if (fh->fh_version == 1) {
 137                 int len;
 138
 139                 if (--data_left < 0)
 140                         return error;
 141                 if (fh->fh_auth_type != 0)
 142                         return error;
 143                 len = key_len(fh->fh_fsid_type) / 4;
 144                 if (len == 0)
 145                         return error;
 146                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 147                         /* deprecated, convert to type 3 */
 148                         len = key_len(FSID_ENCODE_DEV)/4;
 149                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 150                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 151                         fh->fh_fsid[1] = fh->fh_fsid[2];
 152                 }
 153                 data_left -= len;
 154                 if (data_left < 0)
 155                         return error;
 156                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
 157                 fid = (struct fid *)(fh->fh_auth + len);
 158         } else {
 159                 __u32 tfh[2];
 160                 dev_t xdev;
 161                 ino_t xino;
 162
 163                 if (fh->fh_size != NFS_FHSIZE)
 164                         return error;
 165                 /* assume old filehandle format */
 166                 xdev = old_decode_dev(fh->ofh_xdev);
 167                 xino = u32_to_ino_t(fh->ofh_xino);
 168                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 169                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 170         }
 171
 172         error = nfserr_stale;
 173         if (PTR_ERR(exp) == -ENOENT)
 174                 return error;
 175
 176         if (IS_ERR(exp))
 177                 return nfserrno(PTR_ERR(exp));
 178
 179         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 180                 /* Elevate privileges so that the lack of 'r' or 'x'
 181                  * permission on some parent directory will
 182                  * not stop exportfs_decode_fh from being able
 183                  * to reconnect a directory into the dentry cache.
 184                  * The same problem can affect "SUBTREECHECK" exports,
 185                  * but as nfsd_acceptable depends on correct
 186                  * access control settings being in effect, we cannot
 187                  * fix that case easily.
 188                  */
 189                 current->cap_effective =
 190                         cap_raise_nfsd_set(current->cap_effective,
 191                                            current->cap_permitted);
 192         } else {
 193                 error = nfsd_setuser_and_check_port(rqstp, exp);
 194                 if (error)
 195                         goto out;
 196         }
 197
 198         /*
 199          * Look up the dentry using the NFS file handle.
 200          */
 201         error = nfserr_stale;
 202         if (rqstp->rq_vers > 2)
 203                 error = nfserr_badhandle;
 204
 205         if (fh->fh_version != 1) {
 206                 sfid.i32.ino = fh->ofh_ino;
 207                 sfid.i32.gen = fh->ofh_generation;
 208                 sfid.i32.parent_ino = fh->ofh_dirino;
 209                 fid = &sfid;
 210                 data_left = 3;
 211                 if (fh->ofh_dirino == 0)
 212                         fileid_type = FILEID_INO32_GEN;
 213                 else
 214                         fileid_type = FILEID_INO32_GEN_PARENT;
 215         } else
 216                 fileid_type = fh->fh_fileid_type;
 217
 218         if (fileid_type == FILEID_ROOT)
 219                 dentry = dget(exp->ex_path.dentry);
 220         else {
 221                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 222                                 data_left, fileid_type,
 223                                 nfsd_acceptable, exp);
 224         }
 225         if (dentry == NULL)
 226                 goto out;
 227         if (IS_ERR(dentry)) {
 228                 if (PTR_ERR(dentry) != -EINVAL)
 229                         error = nfserrno(PTR_ERR(dentry));
 230                 goto out;
 231         }
 232
 233         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 234                 error = nfsd_setuser_and_check_port(rqstp, exp);
 235                 if (error) {
 236                         dput(dentry);
 237                         goto out;
 238                 }
 239         }
 240
 241         if (S_ISDIR(dentry->d_inode->i_mode) &&
 242                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 243                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 244                                 dentry->d_parent->d_name.name, dentry->d_name.name);
 245         }
 246
 247         fhp->fh_dentry = dentry;
 248         fhp->fh_export = exp;
 249         nfsd_nr_verified++;
 250         return 0;
 251 out:
 252         exp_put(exp);
 253         return error;
 254 }
 255
 256 /*
 257  * Perform sanity checks on the dentry in a client's file handle.
 258  *
 259  * Note that the file handle dentry may need to be freed even after
 260  * an error return.
 261  *
 262  * This is only called at the start of an nfsproc call, so fhp points to
 263  * a svc_fh which is all 0 except for the over-the-wire file handle.
 264  */
 265 __be32
 266 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 267 {
 268         struct svc_export *exp;
 269         struct dentry   *dentry;
 270         __be32          error;
 271
 272         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 273
 274         if (!fhp->fh_dentry) {
 275                 error = nfsd_set_fh_dentry(rqstp, fhp);
 276                 if (error)
 277                         goto out;
 278                 dentry = fhp->fh_dentry;
 279                 exp = fhp->fh_export;
 280         } else {
 281                 /*
 282                  * just rechecking permissions
 283                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create
 284                  * does as well)
 285                  */
 286                 dprintk("nfsd: fh_verify - just checking\n");
 287                 dentry = fhp->fh_dentry;
 288                 exp = fhp->fh_export;
 289                 /*
 290                  * Set user creds for this exportpoint; necessary even
 291                  * in the "just checking" case because this may be a
 292                  * filehandle that was created by fh_compose, and that
 293                  * is about to be used in another nfsv4 compound
 294                  * operation.
 295                  */
 296                 error = nfsd_setuser_and_check_port(rqstp, exp);
 297                 if (error)
 298                         goto out;
 299         }
 300
 301         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 302         if (error)
 303                 goto out;
 304
 305         /*
 306          * pseudoflavor restrictions are not enforced on NLM,
 307          * which clients virtually always use auth_sys for,
 308          * even while using RPCSEC_GSS for NFS.
 309          */
 310         if (access & NFSD_MAY_LOCK)
 311                 goto skip_pseudoflavor_check;
 312         /*
 313          * Clients may expect to be able to use auth_sys during mount,
 314          * even if they use gss for everything else; see section 2.3.2
 315          * of rfc 2623.
 316          */
 317         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 318                         && exp->ex_path.dentry == dentry)
 319                 goto skip_pseudoflavor_check;
 320
 321         error = check_nfsd_access(exp, rqstp);
 322         if (error)
 323                 goto out;
 324
 325 skip_pseudoflavor_check:
 326         /* Finally, check access permissions. */
 327         error = nfsd_permission(rqstp, exp, dentry, access);
 328
 329         if (error) {
 330                 dprintk("fh_verify: %s/%s permission failure, "
 331                         "acc=%x, error=%d\n",
 332                         dentry->d_parent->d_name.name,
 333                         dentry->d_name.name,
 334                         access, ntohl(error));
 335         }
 336 out:
 337         if (error == nfserr_stale)
 338                 nfsdstats.fh_stale++;
 339         return error;
 340 }
 341
 342
 343 /*
 344  * Compose a file handle for an NFS reply.
 345  *
 346  * Note that when first composed, the dentry may not yet have
 347  * an inode.  In this case a call to fh_update should be made
 348  * before the fh goes out on the wire ...
 349  */
 350 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 351                 struct dentry *dentry)
 352 {
 353         if (dentry != exp->ex_path.dentry) {
 354                 struct fid *fid = (struct fid *)
 355                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 356                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 357                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 358
 359                 fhp->fh_handle.fh_fileid_type =
 360                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 361                 fhp->fh_handle.fh_size += maxsize * 4;
 362         } else {
 363                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 364         }
 365 }
 366
 367 /*
 368  * for composing old style file handles
 369  */
 370 static inline void _fh_update_old(struct dentry *dentry,
 371                                   struct svc_export *exp,
 372                                   struct knfsd_fh *fh)
 373 {
 374         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 375         fh->ofh_generation = dentry->d_inode->i_generation;
 376         if (S_ISDIR(dentry->d_inode->i_mode) ||
 377             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 378                 fh->ofh_dirino = 0;
 379 }
 380
 381 __be32
 382 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 383            struct svc_fh *ref_fh)
 384 {
 385         /* ref_fh is a reference file handle.
 386          * if it is non-null and for the same filesystem, then we should compose
 387          * a filehandle which is of the same version, where possible.
 388          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 389          * Then create a 32byte filehandle using nfs_fhbase_old
 390          *
 391          */
 392
 393         u8 version;
 394         u8 fsid_type = 0;
 395         struct inode * inode = dentry->d_inode;
 396         struct dentry *parent = dentry->d_parent;
 397         __u32 *datap;
 398         dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev;
 399         int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root);
 400
 401         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 402                 MAJOR(ex_dev), MINOR(ex_dev),
 403                 (long) exp->ex_path.dentry->d_inode->i_ino,
 404                 parent->d_name.name, dentry->d_name.name,
 405                 (inode ? inode->i_ino : 0));
 406
 407         /* Choose filehandle version and fsid type based on
 408          * the reference filehandle (if it is in the same export)
 409          * or the export options.
 410          */
 411  retry:
 412         version = 1;
 413         if (ref_fh && ref_fh->fh_export == exp) {
 414                 version = ref_fh->fh_handle.fh_version;
 415                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 416
 417                 if (ref_fh == fhp)
 418                         fh_put(ref_fh);
 419                 ref_fh = NULL;
 420
 421                 switch (version) {
 422                 case 0xca:
 423                         fsid_type = FSID_DEV;
 424                         break;
 425                 case 1:
 426                         break;
 427                 default:
 428                         goto retry;
 429                 }
 430
 431                 /* Need to check that this type works for this
 432                  * export point.  As the fsid -> filesystem mapping
 433                  * was guided by user-space, there is no guarantee
 434                  * that the filesystem actually supports that fsid
 435                  * type. If it doesn't we loop around again without
 436                  * ref_fh set.
 437                  */
 438                 switch(fsid_type) {
 439                 case FSID_DEV:
 440                         if (!old_valid_dev(ex_dev))
 441                                 goto retry;
 442                         /* FALL THROUGH */
 443                 case FSID_MAJOR_MINOR:
 444                 case FSID_ENCODE_DEV:
 445                         if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 446                               & FS_REQUIRES_DEV))
 447                                 goto retry;
 448                         break;
 449                 case FSID_NUM:
 450                         if (! (exp->ex_flags & NFSEXP_FSID))
 451                                 goto retry;
 452                         break;
 453                 case FSID_UUID8:
 454                 case FSID_UUID16:
 455                         if (!root_export)
 456                                 goto retry;
 457                         /* fall through */
 458                 case FSID_UUID4_INUM:
 459                 case FSID_UUID16_INUM:
 460                         if (exp->ex_uuid == NULL)
 461                                 goto retry;
 462                         break;
 463                 }
 464         } else if (exp->ex_uuid) {
 465                 if (fhp->fh_maxsize >= 64) {
 466                         if (root_export)
 467                                 fsid_type = FSID_UUID16;
 468                         else
 469                                 fsid_type = FSID_UUID16_INUM;
 470                 } else {
 471                         if (root_export)
 472                                 fsid_type = FSID_UUID8;
 473                         else
 474                                 fsid_type = FSID_UUID4_INUM;
 475                 }
 476         } else if (exp->ex_flags & NFSEXP_FSID)
 477                 fsid_type = FSID_NUM;
 478         else if (!old_valid_dev(ex_dev))
 479                 /* for newer device numbers, we must use a newer fsid format */
 480                 fsid_type = FSID_ENCODE_DEV;
 481         else
 482                 fsid_type = FSID_DEV;
 483
 484         if (ref_fh == fhp)
 485                 fh_put(ref_fh);
 486
 487         if (fhp->fh_locked || fhp->fh_dentry) {
 488                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 489                        parent->d_name.name, dentry->d_name.name);
 490         }
 491         if (fhp->fh_maxsize < NFS_FHSIZE)
 492                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 493                        fhp->fh_maxsize,
 494                        parent->d_name.name, dentry->d_name.name);
 495
 496         fhp->fh_dentry = dget(dentry); /* our internal copy */
 497         fhp->fh_export = exp;
 498         cache_get(&exp->h);
 499
 500         if (version == 0xca) {
 501                 /* old style filehandle please */
 502                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 503                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 504                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 505                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 506                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 507                 fhp->fh_handle.ofh_xino =
 508                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 509                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 510                 if (inode)
 511                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 512         } else {
 513                 int len;
 514                 fhp->fh_handle.fh_version = 1;
 515                 fhp->fh_handle.fh_auth_type = 0;
 516                 datap = fhp->fh_handle.fh_auth+0;
 517                 fhp->fh_handle.fh_fsid_type = fsid_type;
 518                 mk_fsid(fsid_type, datap, ex_dev,
 519                         exp->ex_path.dentry->d_inode->i_ino,
 520                         exp->ex_fsid, exp->ex_uuid);
 521
 522                 len = key_len(fsid_type);
 523                 datap += len/4;
 524                 fhp->fh_handle.fh_size = 4 + len;
 525
 526                 if (inode)
 527                         _fh_update(fhp, exp, dentry);
 528                 if (fhp->fh_handle.fh_fileid_type == 255)
 529                         return nfserr_opnotsupp;
 530         }
 531
 532         nfsd_nr_verified++;
 533         return 0;
 534 }
 535
 536 /*
 537  * Update file handle information after changing a dentry.
 538  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 539  */
 540 __be32
 541 fh_update(struct svc_fh *fhp)
 542 {
 543         struct dentry *dentry;
 544
 545         if (!fhp->fh_dentry)
 546                 goto out_bad;
 547
 548         dentry = fhp->fh_dentry;
 549         if (!dentry->d_inode)
 550                 goto out_negative;
 551         if (fhp->fh_handle.fh_version != 1) {
 552                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 553         } else {
 554                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 555                         goto out;
 556
 557                 _fh_update(fhp, fhp->fh_export, dentry);
 558                 if (fhp->fh_handle.fh_fileid_type == 255)
 559                         return nfserr_opnotsupp;
 560         }
 561 out:
 562         return 0;
 563
 564 out_bad:
 565         printk(KERN_ERR "fh_update: fh not verified!\n");
 566         goto out;
 567 out_negative:
 568         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 569                 dentry->d_parent->d_name.name, dentry->d_name.name);
 570         goto out;
 571 }
 572
 573 /*
 574  * Release a file handle.
 575  */
 576 void
 577 fh_put(struct svc_fh *fhp)
 578 {
 579         struct dentry * dentry = fhp->fh_dentry;
 580         struct svc_export * exp = fhp->fh_export;
 581         if (dentry) {
 582                 fh_unlock(fhp);
 583                 fhp->fh_dentry = NULL;
 584                 dput(dentry);
 585 #ifdef CONFIG_NFSD_V3
 586                 fhp->fh_pre_saved = 0;
 587                 fhp->fh_post_saved = 0;
 588 #endif
 589                 nfsd_nr_put++;
 590         }
 591         if (exp) {
 592                 cache_put(&exp->h, &svc_export_cache);
 593                 fhp->fh_export = NULL;
 594         }
 595         return;
 596 }
 597
 598 /*
 599  * Shorthand for dprintk()'s
 600  */
 601 char * SVCFH_fmt(struct svc_fh *fhp)
 602 {
 603         struct knfsd_fh *fh = &fhp->fh_handle;
 604
 605         static char buf[80];
 606         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 607                 fh->fh_size,
 608                 fh->fh_base.fh_pad[0],
 609                 fh->fh_base.fh_pad[1],
 610                 fh->fh_base.fh_pad[2],
 611                 fh->fh_base.fh_pad[3],
 612                 fh->fh_base.fh_pad[4],
 613                 fh->fh_base.fh_pad[5]);
 614         return buf;
 615 }
 616
 617 enum fsid_source fsid_source(struct svc_fh *fhp)
 618 {
 619         if (fhp->fh_handle.fh_version != 1)
 620                 return FSIDSOURCE_DEV;
 621         switch(fhp->fh_handle.fh_fsid_type) {
 622         case FSID_DEV:
 623         case FSID_ENCODE_DEV:
 624         case FSID_MAJOR_MINOR:
 625                 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 626                     & FS_REQUIRES_DEV)
 627                         return FSIDSOURCE_DEV;
 628                 break;
 629         case FSID_NUM:
 630                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 631                         return FSIDSOURCE_FSID;
 632                 break;
 633         default:
 634                 break;
 635         }
 636         /* either a UUID type filehandle, or the filehandle doesn't
 637          * match the export.
 638          */
 639         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 640                 return FSIDSOURCE_FSID;
 641         if (fhp->fh_export->ex_uuid)
 642                 return FSIDSOURCE_UUID;
 643         return FSIDSOURCE_DEV;
 644 }