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 %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 (!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: %pd2\n",
 257                                 dentry);
 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: %pd2 permission failure, "
 365                         "acc=%x, error=%d\n",
 366                         dentry,
 367                         access, ntohl(error));
 368         }
 369 out:
 370         if (error == nfserr_stale)
 371                 nfsdstats.fh_stale++;
 372         return error;
 373 }
 374
 375
 376 /*
 377  * Compose a file handle for an NFS reply.
 378  *
 379  * Note that when first composed, the dentry may not yet have
 380  * an inode.  In this case a call to fh_update should be made
 381  * before the fh goes out on the wire ...
 382  */
 383 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 384                 struct dentry *dentry)
 385 {
 386         if (dentry != exp->ex_path.dentry) {
 387                 struct fid *fid = (struct fid *)
 388                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 389                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 390                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 391
 392                 fhp->fh_handle.fh_fileid_type =
 393                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 394                 fhp->fh_handle.fh_size += maxsize * 4;
 395         } else {
 396                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 397         }
 398 }
 399
 400 /*
 401  * for composing old style file handles
 402  */
 403 static inline void _fh_update_old(struct dentry *dentry,
 404                                   struct svc_export *exp,
 405                                   struct knfsd_fh *fh)
 406 {
 407         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 408         fh->ofh_generation = dentry->d_inode->i_generation;
 409         if (S_ISDIR(dentry->d_inode->i_mode) ||
 410             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 411                 fh->ofh_dirino = 0;
 412 }
 413
 414 static bool is_root_export(struct svc_export *exp)
 415 {
 416         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 417 }
 418
 419 static struct super_block *exp_sb(struct svc_export *exp)
 420 {
 421         return exp->ex_path.dentry->d_inode->i_sb;
 422 }
 423
 424 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 425 {
 426         switch (fsid_type) {
 427         case FSID_DEV:
 428                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 429                         return 0;
 430                 /* FALL THROUGH */
 431         case FSID_MAJOR_MINOR:
 432         case FSID_ENCODE_DEV:
 433                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 434         case FSID_NUM:
 435                 return exp->ex_flags & NFSEXP_FSID;
 436         case FSID_UUID8:
 437         case FSID_UUID16:
 438                 if (!is_root_export(exp))
 439                         return 0;
 440                 /* fall through */
 441         case FSID_UUID4_INUM:
 442         case FSID_UUID16_INUM:
 443                 return exp->ex_uuid != NULL;
 444         }
 445         return 1;
 446 }
 447
 448
 449 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 450 {
 451         u8 version;
 452         u8 fsid_type;
 453 retry:
 454         version = 1;
 455         if (ref_fh && ref_fh->fh_export == exp) {
 456                 version = ref_fh->fh_handle.fh_version;
 457                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 458
 459                 ref_fh = NULL;
 460
 461                 switch (version) {
 462                 case 0xca:
 463                         fsid_type = FSID_DEV;
 464                         break;
 465                 case 1:
 466                         break;
 467                 default:
 468                         goto retry;
 469                 }
 470
 471                 /*
 472                  * As the fsid -> filesystem mapping was guided by
 473                  * user-space, there is no guarantee that the filesystem
 474                  * actually supports that fsid type. If it doesn't we
 475                  * loop around again without ref_fh set.
 476                  */
 477                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 478                         goto retry;
 479         } else if (exp->ex_flags & NFSEXP_FSID) {
 480                 fsid_type = FSID_NUM;
 481         } else if (exp->ex_uuid) {
 482                 if (fhp->fh_maxsize >= 64) {
 483                         if (is_root_export(exp))
 484                                 fsid_type = FSID_UUID16;
 485                         else
 486                                 fsid_type = FSID_UUID16_INUM;
 487                 } else {
 488                         if (is_root_export(exp))
 489                                 fsid_type = FSID_UUID8;
 490                         else
 491                                 fsid_type = FSID_UUID4_INUM;
 492                 }
 493         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 494                 /* for newer device numbers, we must use a newer fsid format */
 495                 fsid_type = FSID_ENCODE_DEV;
 496         else
 497                 fsid_type = FSID_DEV;
 498         fhp->fh_handle.fh_version = version;
 499         if (version)
 500                 fhp->fh_handle.fh_fsid_type = fsid_type;
 501 }
 502
 503 __be32
 504 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 505            struct svc_fh *ref_fh)
 506 {
 507         /* ref_fh is a reference file handle.
 508          * if it is non-null and for the same filesystem, then we should compose
 509          * a filehandle which is of the same version, where possible.
 510          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 511          * Then create a 32byte filehandle using nfs_fhbase_old
 512          *
 513          */
 514
 515         struct inode * inode = dentry->d_inode;
 516         __u32 *datap;
 517         dev_t ex_dev = exp_sb(exp)->s_dev;
 518
 519         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
 520                 MAJOR(ex_dev), MINOR(ex_dev),
 521                 (long) exp->ex_path.dentry->d_inode->i_ino,
 522                 dentry,
 523                 (inode ? inode->i_ino : 0));
 524
 525         /* Choose filehandle version and fsid type based on
 526          * the reference filehandle (if it is in the same export)
 527          * or the export options.
 528          */
 529          set_version_and_fsid_type(fhp, exp, ref_fh);
 530
 531         if (ref_fh == fhp)
 532                 fh_put(ref_fh);
 533
 534         if (fhp->fh_locked || fhp->fh_dentry) {
 535                 printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
 536                        dentry);
 537         }
 538         if (fhp->fh_maxsize < NFS_FHSIZE)
 539                 printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
 540                        fhp->fh_maxsize,
 541                        dentry);
 542
 543         fhp->fh_dentry = dget(dentry); /* our internal copy */
 544         fhp->fh_export = exp;
 545         cache_get(&exp->h);
 546
 547         if (fhp->fh_handle.fh_version == 0xca) {
 548                 /* old style filehandle please */
 549                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 550                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 551                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 552                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 553                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 554                 fhp->fh_handle.ofh_xino =
 555                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 556                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 557                 if (inode)
 558                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 559         } else {
 560                 int len;
 561                 fhp->fh_handle.fh_auth_type = 0;
 562                 datap = fhp->fh_handle.fh_auth+0;
 563                 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
 564                         exp->ex_path.dentry->d_inode->i_ino,
 565                         exp->ex_fsid, exp->ex_uuid);
 566
 567                 len = key_len(fhp->fh_handle.fh_fsid_type);
 568                 datap += len/4;
 569                 fhp->fh_handle.fh_size = 4 + len;
 570
 571                 if (inode)
 572                         _fh_update(fhp, exp, dentry);
 573                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
 574                         fh_put(fhp);
 575                         return nfserr_opnotsupp;
 576                 }
 577         }
 578
 579         return 0;
 580 }
 581
 582 /*
 583  * Update file handle information after changing a dentry.
 584  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 585  */
 586 __be32
 587 fh_update(struct svc_fh *fhp)
 588 {
 589         struct dentry *dentry;
 590
 591         if (!fhp->fh_dentry)
 592                 goto out_bad;
 593
 594         dentry = fhp->fh_dentry;
 595         if (!dentry->d_inode)
 596                 goto out_negative;
 597         if (fhp->fh_handle.fh_version != 1) {
 598                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 599         } else {
 600                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 601                         return 0;
 602
 603                 _fh_update(fhp, fhp->fh_export, dentry);
 604                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
 605                         return nfserr_opnotsupp;
 606         }
 607         return 0;
 608 out_bad:
 609         printk(KERN_ERR "fh_update: fh not verified!\n");
 610         return nfserr_serverfault;
 611 out_negative:
 612         printk(KERN_ERR "fh_update: %pd2 still negative!\n",
 613                 dentry);
 614         return nfserr_serverfault;
 615 }
 616
 617 /*
 618  * Release a file handle.
 619  */
 620 void
 621 fh_put(struct svc_fh *fhp)
 622 {
 623         struct dentry * dentry = fhp->fh_dentry;
 624         struct svc_export * exp = fhp->fh_export;
 625         if (dentry) {
 626                 fh_unlock(fhp);
 627                 fhp->fh_dentry = NULL;
 628                 dput(dentry);
 629 #ifdef CONFIG_NFSD_V3
 630                 fhp->fh_pre_saved = 0;
 631                 fhp->fh_post_saved = 0;
 632 #endif
 633         }
 634         fh_drop_write(fhp);
 635         if (exp) {
 636                 exp_put(exp);
 637                 fhp->fh_export = NULL;
 638         }
 639         return;
 640 }
 641
 642 /*
 643  * Shorthand for dprintk()'s
 644  */
 645 char * SVCFH_fmt(struct svc_fh *fhp)
 646 {
 647         struct knfsd_fh *fh = &fhp->fh_handle;
 648
 649         static char buf[80];
 650         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 651                 fh->fh_size,
 652                 fh->fh_base.fh_pad[0],
 653                 fh->fh_base.fh_pad[1],
 654                 fh->fh_base.fh_pad[2],
 655                 fh->fh_base.fh_pad[3],
 656                 fh->fh_base.fh_pad[4],
 657                 fh->fh_base.fh_pad[5]);
 658         return buf;
 659 }
 660
 661 enum fsid_source fsid_source(struct svc_fh *fhp)
 662 {
 663         if (fhp->fh_handle.fh_version != 1)
 664                 return FSIDSOURCE_DEV;
 665         switch(fhp->fh_handle.fh_fsid_type) {
 666         case FSID_DEV:
 667         case FSID_ENCODE_DEV:
 668         case FSID_MAJOR_MINOR:
 669                 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 670                         return FSIDSOURCE_DEV;
 671                 break;
 672         case FSID_NUM:
 673                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 674                         return FSIDSOURCE_FSID;
 675                 break;
 676         default:
 677                 break;
 678         }
 679         /* either a UUID type filehandle, or the filehandle doesn't
 680          * match the export.
 681          */
 682         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 683                 return FSIDSOURCE_FSID;
 684         if (fhp->fh_export->ex_uuid)
 685                 return FSIDSOURCE_UUID;
 686         return FSIDSOURCE_DEV;
 687 }