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