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, umode_t mode, umode_t requested)
  63 {
  64         mode &= S_IFMT;
  65
  66         if (requested == 0) /* the caller doesn't care */
  67                 return nfs_ok;
  68         if (mode == requested)
  69                 return nfs_ok;
  70         /*
  71          * v4 has an error more specific than err_notdir which we should
  72          * return in preference to err_notdir:
  73          */
  74         if (rqstp->rq_vers == 4 && mode == S_IFLNK)
  75                 return nfserr_symlink;
  76         if (requested == S_IFDIR)
  77                 return nfserr_notdir;
  78         if (mode == S_IFDIR)
  79                 return nfserr_isdir;
  80         return nfserr_inval;
  81 }
  82
  83 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
  84                                           struct svc_export *exp)
  85 {
  86         int flags = nfsexp_flags(rqstp, exp);
  87
  88         /* Check if the request originated from a secure port. */
  89         if (!test_bit(RQ_SECURE, &rqstp->rq_flags) && !(flags & NFSEXP_INSECURE_PORT)) {
  90                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
  91                 dprintk("nfsd: request from insecure port %s!\n",
  92                         svc_print_addr(rqstp, buf, sizeof(buf)));
  93                 return nfserr_perm;
  94         }
  95
  96         /* Set user creds for this exportpoint */
  97         return nfserrno(nfsd_setuser(rqstp, exp));
  98 }
  99
 100 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
 101         struct dentry *dentry, struct svc_export *exp)
 102 {
 103         if (!(exp->ex_flags & NFSEXP_V4ROOT))
 104                 return nfs_ok;
 105         /*
 106          * v2/v3 clients have no need for the V4ROOT export--they use
 107          * the mount protocl instead; also, further V4ROOT checks may be
 108          * in v4-specific code, in which case v2/v3 clients could bypass
 109          * them.
 110          */
 111         if (!nfsd_v4client(rqstp))
 112                 return nfserr_stale;
 113         /*
 114          * We're exposing only the directories and symlinks that have to be
 115          * traversed on the way to real exports:
 116          */
 117         if (unlikely(!d_is_dir(dentry) &&
 118                      !d_is_symlink(dentry)))
 119                 return nfserr_stale;
 120         /*
 121          * A pseudoroot export gives permission to access only one
 122          * single directory; the kernel has to make another upcall
 123          * before granting access to anything else under it:
 124          */
 125         if (unlikely(dentry != exp->ex_path.dentry))
 126                 return nfserr_stale;
 127         return nfs_ok;
 128 }
 129
 130 /*
 131  * Use the given filehandle to look up the corresponding export and
 132  * dentry.  On success, the results are used to set fh_export and
 133  * fh_dentry.
 134  */
 135 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 136 {
 137         struct knfsd_fh *fh = &fhp->fh_handle;
 138         struct fid *fid = NULL, sfid;
 139         struct svc_export *exp;
 140         struct dentry *dentry;
 141         int fileid_type;
 142         int data_left = fh->fh_size/4;
 143         __be32 error;
 144
 145         error = nfserr_stale;
 146         if (rqstp->rq_vers > 2)
 147                 error = nfserr_badhandle;
 148         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 149                 return nfserr_nofilehandle;
 150
 151         if (fh->fh_version == 1) {
 152                 int len;
 153
 154                 if (--data_left < 0)
 155                         return error;
 156                 if (fh->fh_auth_type != 0)
 157                         return error;
 158                 len = key_len(fh->fh_fsid_type) / 4;
 159                 if (len == 0)
 160                         return error;
 161                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 162                         /* deprecated, convert to type 3 */
 163                         len = key_len(FSID_ENCODE_DEV)/4;
 164                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 165                         /*
 166                          * struct knfsd_fh uses host-endian fields, which are
 167                          * sometimes used to hold net-endian values. This
 168                          * confuses sparse, so we must use __force here to
 169                          * keep it from complaining.
 170                          */
 171                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
 172                                                         ntohl((__force __be32)fh->fh_fsid[1])));
 173                         fh->fh_fsid[1] = fh->fh_fsid[2];
 174                 }
 175                 data_left -= len;
 176                 if (data_left < 0)
 177                         return error;
 178                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
 179                 fid = (struct fid *)(fh->fh_fsid + len);
 180         } else {
 181                 __u32 tfh[2];
 182                 dev_t xdev;
 183                 ino_t xino;
 184
 185                 if (fh->fh_size != NFS_FHSIZE)
 186                         return error;
 187                 /* assume old filehandle format */
 188                 xdev = old_decode_dev(fh->ofh_xdev);
 189                 xino = u32_to_ino_t(fh->ofh_xino);
 190                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 191                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 192         }
 193
 194         error = nfserr_stale;
 195         if (PTR_ERR(exp) == -ENOENT)
 196                 return error;
 197
 198         if (IS_ERR(exp))
 199                 return nfserrno(PTR_ERR(exp));
 200
 201         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 202                 /* Elevate privileges so that the lack of 'r' or 'x'
 203                  * permission on some parent directory will
 204                  * not stop exportfs_decode_fh from being able
 205                  * to reconnect a directory into the dentry cache.
 206                  * The same problem can affect "SUBTREECHECK" exports,
 207                  * but as nfsd_acceptable depends on correct
 208                  * access control settings being in effect, we cannot
 209                  * fix that case easily.
 210                  */
 211                 struct cred *new = prepare_creds();
 212                 if (!new) {
 213                         error =  nfserrno(-ENOMEM);
 214                         goto out;
 215                 }
 216                 new->cap_effective =
 217                         cap_raise_nfsd_set(new->cap_effective,
 218                                            new->cap_permitted);
 219                 put_cred(override_creds(new));
 220                 put_cred(new);
 221         } else {
 222                 error = nfsd_setuser_and_check_port(rqstp, exp);
 223                 if (error)
 224                         goto out;
 225         }
 226
 227         /*
 228          * Look up the dentry using the NFS file handle.
 229          */
 230         error = nfserr_stale;
 231         if (rqstp->rq_vers > 2)
 232                 error = nfserr_badhandle;
 233
 234         if (fh->fh_version != 1) {
 235                 sfid.i32.ino = fh->ofh_ino;
 236                 sfid.i32.gen = fh->ofh_generation;
 237                 sfid.i32.parent_ino = fh->ofh_dirino;
 238                 fid = &sfid;
 239                 data_left = 3;
 240                 if (fh->ofh_dirino == 0)
 241                         fileid_type = FILEID_INO32_GEN;
 242                 else
 243                         fileid_type = FILEID_INO32_GEN_PARENT;
 244         } else
 245                 fileid_type = fh->fh_fileid_type;
 246
 247         if (fileid_type == FILEID_ROOT)
 248                 dentry = dget(exp->ex_path.dentry);
 249         else {
 250                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 251                                 data_left, fileid_type,
 252                                 nfsd_acceptable, exp);
 253         }
 254         if (dentry == NULL)
 255                 goto out;
 256         if (IS_ERR(dentry)) {
 257                 if (PTR_ERR(dentry) != -EINVAL)
 258                         error = nfserrno(PTR_ERR(dentry));
 259                 goto out;
 260         }
 261
 262         if (d_is_dir(dentry) &&
 263                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 264                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
 265                                 dentry);
 266         }
 267
 268         fhp->fh_dentry = dentry;
 269         fhp->fh_export = exp;
 270         return 0;
 271 out:
 272         exp_put(exp);
 273         return error;
 274 }
 275
 276 /**
 277  * fh_verify - filehandle lookup and access checking
 278  * @rqstp: pointer to current rpc request
 279  * @fhp: filehandle to be verified
 280  * @type: expected type of object pointed to by filehandle
 281  * @access: type of access needed to object
 282  *
 283  * Look up a dentry from the on-the-wire filehandle, check the client's
 284  * access to the export, and set the current task's credentials.
 285  *
 286  * Regardless of success or failure of fh_verify(), fh_put() should be
 287  * called on @fhp when the caller is finished with the filehandle.
 288  *
 289  * fh_verify() may be called multiple times on a given filehandle, for
 290  * example, when processing an NFSv4 compound.  The first call will look
 291  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
 292  * skip the lookup and just perform the other checks and possibly change
 293  * the current task's credentials.
 294  *
 295  * @type specifies the type of object expected using one of the S_IF*
 296  * constants defined in include/linux/stat.h.  The caller may use zero
 297  * to indicate that it doesn't care, or a negative integer to indicate
 298  * that it expects something not of the given type.
 299  *
 300  * @access is formed from the NFSD_MAY_* constants defined in
 301  * include/linux/nfsd/nfsd.h.
 302  */
 303 __be32
 304 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
 305 {
 306         struct svc_export *exp;
 307         struct dentry   *dentry;
 308         __be32          error;
 309
 310         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 311
 312         if (!fhp->fh_dentry) {
 313                 error = nfsd_set_fh_dentry(rqstp, fhp);
 314                 if (error)
 315                         goto out;
 316         }
 317         dentry = fhp->fh_dentry;
 318         exp = fhp->fh_export;
 319         /*
 320          * We still have to do all these permission checks, even when
 321          * fh_dentry is already set:
 322          *      - fh_verify may be called multiple times with different
 323          *        "access" arguments (e.g. nfsd_proc_create calls
 324          *        fh_verify(...,NFSD_MAY_EXEC) first, then later (in
 325          *        nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
 326          *      - in the NFSv4 case, the filehandle may have been filled
 327          *        in by fh_compose, and given a dentry, but further
 328          *        compound operations performed with that filehandle
 329          *        still need permissions checks.  In the worst case, a
 330          *        mountpoint crossing may have changed the export
 331          *        options, and we may now need to use a different uid
 332          *        (for example, if different id-squashing options are in
 333          *        effect on the new filesystem).
 334          */
 335         error = check_pseudo_root(rqstp, dentry, exp);
 336         if (error)
 337                 goto out;
 338
 339         error = nfsd_setuser_and_check_port(rqstp, exp);
 340         if (error)
 341                 goto out;
 342
 343         error = nfsd_mode_check(rqstp, d_inode(dentry)->i_mode, type);
 344         if (error)
 345                 goto out;
 346
 347         /*
 348          * pseudoflavor restrictions are not enforced on NLM,
 349          * which clients virtually always use auth_sys for,
 350          * even while using RPCSEC_GSS for NFS.
 351          */
 352         if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
 353                 goto skip_pseudoflavor_check;
 354         /*
 355          * Clients may expect to be able to use auth_sys during mount,
 356          * even if they use gss for everything else; see section 2.3.2
 357          * of rfc 2623.
 358          */
 359         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 360                         && exp->ex_path.dentry == dentry)
 361                 goto skip_pseudoflavor_check;
 362
 363         error = check_nfsd_access(exp, rqstp);
 364         if (error)
 365                 goto out;
 366
 367 skip_pseudoflavor_check:
 368         /* Finally, check access permissions. */
 369         error = nfsd_permission(rqstp, exp, dentry, access);
 370
 371         if (error) {
 372                 dprintk("fh_verify: %pd2 permission failure, "
 373                         "acc=%x, error=%d\n",
 374                         dentry,
 375                         access, ntohl(error));
 376         }
 377 out:
 378         if (error == nfserr_stale)
 379                 nfsdstats.fh_stale++;
 380         return error;
 381 }
 382
 383
 384 /*
 385  * Compose a file handle for an NFS reply.
 386  *
 387  * Note that when first composed, the dentry may not yet have
 388  * an inode.  In this case a call to fh_update should be made
 389  * before the fh goes out on the wire ...
 390  */
 391 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 392                 struct dentry *dentry)
 393 {
 394         if (dentry != exp->ex_path.dentry) {
 395                 struct fid *fid = (struct fid *)
 396                         (fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
 397                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 398                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 399
 400                 fhp->fh_handle.fh_fileid_type =
 401                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 402                 fhp->fh_handle.fh_size += maxsize * 4;
 403         } else {
 404                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 405         }
 406 }
 407
 408 /*
 409  * for composing old style file handles
 410  */
 411 static inline void _fh_update_old(struct dentry *dentry,
 412                                   struct svc_export *exp,
 413                                   struct knfsd_fh *fh)
 414 {
 415         fh->ofh_ino = ino_t_to_u32(d_inode(dentry)->i_ino);
 416         fh->ofh_generation = d_inode(dentry)->i_generation;
 417         if (d_is_dir(dentry) ||
 418             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 419                 fh->ofh_dirino = 0;
 420 }
 421
 422 static bool is_root_export(struct svc_export *exp)
 423 {
 424         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 425 }
 426
 427 static struct super_block *exp_sb(struct svc_export *exp)
 428 {
 429         return d_inode(exp->ex_path.dentry)->i_sb;
 430 }
 431
 432 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 433 {
 434         switch (fsid_type) {
 435         case FSID_DEV:
 436                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 437                         return 0;
 438                 /* FALL THROUGH */
 439         case FSID_MAJOR_MINOR:
 440         case FSID_ENCODE_DEV:
 441                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 442         case FSID_NUM:
 443                 return exp->ex_flags & NFSEXP_FSID;
 444         case FSID_UUID8:
 445         case FSID_UUID16:
 446                 if (!is_root_export(exp))
 447                         return 0;
 448                 /* fall through */
 449         case FSID_UUID4_INUM:
 450         case FSID_UUID16_INUM:
 451                 return exp->ex_uuid != NULL;
 452         }
 453         return 1;
 454 }
 455
 456
 457 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 458 {
 459         u8 version;
 460         u8 fsid_type;
 461 retry:
 462         version = 1;
 463         if (ref_fh && ref_fh->fh_export == exp) {
 464                 version = ref_fh->fh_handle.fh_version;
 465                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 466
 467                 ref_fh = NULL;
 468
 469                 switch (version) {
 470                 case 0xca:
 471                         fsid_type = FSID_DEV;
 472                         break;
 473                 case 1:
 474                         break;
 475                 default:
 476                         goto retry;
 477                 }
 478
 479                 /*
 480                  * As the fsid -> filesystem mapping was guided by
 481                  * user-space, there is no guarantee that the filesystem
 482                  * actually supports that fsid type. If it doesn't we
 483                  * loop around again without ref_fh set.
 484                  */
 485                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 486                         goto retry;
 487         } else if (exp->ex_flags & NFSEXP_FSID) {
 488                 fsid_type = FSID_NUM;
 489         } else if (exp->ex_uuid) {
 490                 if (fhp->fh_maxsize >= 64) {
 491                         if (is_root_export(exp))
 492                                 fsid_type = FSID_UUID16;
 493                         else
 494                                 fsid_type = FSID_UUID16_INUM;
 495                 } else {
 496                         if (is_root_export(exp))
 497                                 fsid_type = FSID_UUID8;
 498                         else
 499                                 fsid_type = FSID_UUID4_INUM;
 500                 }
 501         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 502                 /* for newer device numbers, we must use a newer fsid format */
 503                 fsid_type = FSID_ENCODE_DEV;
 504         else
 505                 fsid_type = FSID_DEV;
 506         fhp->fh_handle.fh_version = version;
 507         if (version)
 508                 fhp->fh_handle.fh_fsid_type = fsid_type;
 509 }
 510
 511 __be32
 512 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 513            struct svc_fh *ref_fh)
 514 {
 515         /* ref_fh is a reference file handle.
 516          * if it is non-null and for the same filesystem, then we should compose
 517          * a filehandle which is of the same version, where possible.
 518          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 519          * Then create a 32byte filehandle using nfs_fhbase_old
 520          *
 521          */
 522
 523         struct inode * inode = d_inode(dentry);
 524         dev_t ex_dev = exp_sb(exp)->s_dev;
 525
 526         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
 527                 MAJOR(ex_dev), MINOR(ex_dev),
 528                 (long) d_inode(exp->ex_path.dentry)->i_ino,
 529                 dentry,
 530                 (inode ? inode->i_ino : 0));
 531
 532         /* Choose filehandle version and fsid type based on
 533          * the reference filehandle (if it is in the same export)
 534          * or the export options.
 535          */
 536          set_version_and_fsid_type(fhp, exp, ref_fh);
 537
 538         if (ref_fh == fhp)
 539                 fh_put(ref_fh);
 540
 541         if (fhp->fh_locked || fhp->fh_dentry) {
 542                 printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
 543                        dentry);
 544         }
 545         if (fhp->fh_maxsize < NFS_FHSIZE)
 546                 printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
 547                        fhp->fh_maxsize,
 548                        dentry);
 549
 550         fhp->fh_dentry = dget(dentry); /* our internal copy */
 551         fhp->fh_export = exp_get(exp);
 552
 553         if (fhp->fh_handle.fh_version == 0xca) {
 554                 /* old style filehandle please */
 555                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 556                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 557                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 558                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 559                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 560                 fhp->fh_handle.ofh_xino =
 561                         ino_t_to_u32(d_inode(exp->ex_path.dentry)->i_ino);
 562                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 563                 if (inode)
 564                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 565         } else {
 566                 fhp->fh_handle.fh_size =
 567                         key_len(fhp->fh_handle.fh_fsid_type) + 4;
 568                 fhp->fh_handle.fh_auth_type = 0;
 569
 570                 mk_fsid(fhp->fh_handle.fh_fsid_type,
 571                         fhp->fh_handle.fh_fsid,
 572                         ex_dev,
 573                         d_inode(exp->ex_path.dentry)->i_ino,
 574                         exp->ex_fsid, exp->ex_uuid);
 575
 576                 if (inode)
 577                         _fh_update(fhp, exp, dentry);
 578                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
 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
 592 fh_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 (d_really_is_negative(dentry))
 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                         return 0;
 607
 608                 _fh_update(fhp, fhp->fh_export, dentry);
 609                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
 610                         return nfserr_opnotsupp;
 611         }
 612         return 0;
 613 out_bad:
 614         printk(KERN_ERR "fh_update: fh not verified!\n");
 615         return nfserr_serverfault;
 616 out_negative:
 617         printk(KERN_ERR "fh_update: %pd2 still negative!\n",
 618                 dentry);
 619         return nfserr_serverfault;
 620 }
 621
 622 /*
 623  * Release a file handle.
 624  */
 625 void
 626 fh_put(struct svc_fh *fhp)
 627 {
 628         struct dentry * dentry = fhp->fh_dentry;
 629         struct svc_export * exp = fhp->fh_export;
 630         if (dentry) {
 631                 fh_unlock(fhp);
 632                 fhp->fh_dentry = NULL;
 633                 dput(dentry);
 634 #ifdef CONFIG_NFSD_V3
 635                 fhp->fh_pre_saved = 0;
 636                 fhp->fh_post_saved = 0;
 637 #endif
 638         }
 639         fh_drop_write(fhp);
 640         if (exp) {
 641                 exp_put(exp);
 642                 fhp->fh_export = NULL;
 643         }
 644         return;
 645 }
 646
 647 /*
 648  * Shorthand for dprintk()'s
 649  */
 650 char * SVCFH_fmt(struct svc_fh *fhp)
 651 {
 652         struct knfsd_fh *fh = &fhp->fh_handle;
 653
 654         static char buf[80];
 655         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 656                 fh->fh_size,
 657                 fh->fh_base.fh_pad[0],
 658                 fh->fh_base.fh_pad[1],
 659                 fh->fh_base.fh_pad[2],
 660                 fh->fh_base.fh_pad[3],
 661                 fh->fh_base.fh_pad[4],
 662                 fh->fh_base.fh_pad[5]);
 663         return buf;
 664 }
 665
 666 enum fsid_source fsid_source(struct svc_fh *fhp)
 667 {
 668         if (fhp->fh_handle.fh_version != 1)
 669                 return FSIDSOURCE_DEV;
 670         switch(fhp->fh_handle.fh_fsid_type) {
 671         case FSID_DEV:
 672         case FSID_ENCODE_DEV:
 673         case FSID_MAJOR_MINOR:
 674                 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 675                         return FSIDSOURCE_DEV;
 676                 break;
 677         case FSID_NUM:
 678                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 679                         return FSIDSOURCE_FSID;
 680                 break;
 681         default:
 682                 break;
 683         }
 684         /* either a UUID type filehandle, or the filehandle doesn't
 685          * match the export.
 686          */
 687         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 688                 return FSIDSOURCE_FSID;
 689         if (fhp->fh_export->ex_uuid)
 690                 return FSIDSOURCE_UUID;
 691         return FSIDSOURCE_DEV;
 692 }