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