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, int type)
  63 {
  64         /* Type can be negative when creating hardlinks - not to a dir */
  65         if (type > 0 && (mode & S_IFMT) != type) {
  66                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  67                         return nfserr_symlink;
  68                 else if (type == S_IFDIR)
  69                         return nfserr_notdir;
  70                 else if ((mode & S_IFMT) == S_IFDIR)
  71                         return nfserr_isdir;
  72                 else
  73                         return nfserr_inval;
  74         }
  75         if (type < 0 && (mode & S_IFMT) == -type) {
  76                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  77                         return nfserr_symlink;
  78                 else if (type == -S_IFDIR)
  79                         return nfserr_isdir;
  80                 else
  81                         return nfserr_notdir;
  82         }
  83         return 0;
  84 }
  85
  86 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
  87                                           struct svc_export *exp)
  88 {
  89         int flags = nfsexp_flags(rqstp, exp);
  90
  91         /* Check if the request originated from a secure port. */
  92         if (!rqstp->rq_secure && !(flags & NFSEXP_INSECURE_PORT)) {
  93                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
  94                 dprintk(KERN_WARNING
  95                        "nfsd: request from insecure port %s!\n",
  96                        svc_print_addr(rqstp, buf, sizeof(buf)));
  97                 return nfserr_perm;
  98         }
  99
 100         /* Set user creds for this exportpoint */
 101         return nfserrno(nfsd_setuser(rqstp, exp));
 102 }
 103
 104 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
 105         struct dentry *dentry, struct svc_export *exp)
 106 {
 107         if (!(exp->ex_flags & NFSEXP_V4ROOT))
 108                 return nfs_ok;
 109         /*
 110          * v2/v3 clients have no need for the V4ROOT export--they use
 111          * the mount protocl instead; also, further V4ROOT checks may be
 112          * in v4-specific code, in which case v2/v3 clients could bypass
 113          * them.
 114          */
 115         if (!nfsd_v4client(rqstp))
 116                 return nfserr_stale;
 117         /*
 118          * We're exposing only the directories and symlinks that have to be
 119          * traversed on the way to real exports:
 120          */
 121         if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
 122                      !S_ISLNK(dentry->d_inode->i_mode)))
 123                 return nfserr_stale;
 124         /*
 125          * A pseudoroot export gives permission to access only one
 126          * single directory; the kernel has to make another upcall
 127          * before granting access to anything else under it:
 128          */
 129         if (unlikely(dentry != exp->ex_path.dentry))
 130                 return nfserr_stale;
 131         return nfs_ok;
 132 }
 133
 134 /*
 135  * Use the given filehandle to look up the corresponding export and
 136  * dentry.  On success, the results are used to set fh_export and
 137  * fh_dentry.
 138  */
 139 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 140 {
 141         struct knfsd_fh *fh = &fhp->fh_handle;
 142         struct fid *fid = NULL, sfid;
 143         struct svc_export *exp;
 144         struct dentry *dentry;
 145         int fileid_type;
 146         int data_left = fh->fh_size/4;
 147         __be32 error;
 148
 149         error = nfserr_stale;
 150         if (rqstp->rq_vers > 2)
 151                 error = nfserr_badhandle;
 152         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 153                 return nfserr_nofilehandle;
 154
 155         if (fh->fh_version == 1) {
 156                 int len;
 157
 158                 if (--data_left < 0)
 159                         return error;
 160                 if (fh->fh_auth_type != 0)
 161                         return error;
 162                 len = key_len(fh->fh_fsid_type) / 4;
 163                 if (len == 0)
 164                         return error;
 165                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 166                         /* deprecated, convert to type 3 */
 167                         len = key_len(FSID_ENCODE_DEV)/4;
 168                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 169                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 170                         fh->fh_fsid[1] = fh->fh_fsid[2];
 171                 }
 172                 data_left -= len;
 173                 if (data_left < 0)
 174                         return error;
 175                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
 176                 fid = (struct fid *)(fh->fh_auth + len);
 177         } else {
 178                 __u32 tfh[2];
 179                 dev_t xdev;
 180                 ino_t xino;
 181
 182                 if (fh->fh_size != NFS_FHSIZE)
 183                         return error;
 184                 /* assume old filehandle format */
 185                 xdev = old_decode_dev(fh->ofh_xdev);
 186                 xino = u32_to_ino_t(fh->ofh_xino);
 187                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 188                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 189         }
 190
 191         error = nfserr_stale;
 192         if (PTR_ERR(exp) == -ENOENT)
 193                 return error;
 194
 195         if (IS_ERR(exp))
 196                 return nfserrno(PTR_ERR(exp));
 197
 198         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 199                 /* Elevate privileges so that the lack of 'r' or 'x'
 200                  * permission on some parent directory will
 201                  * not stop exportfs_decode_fh from being able
 202                  * to reconnect a directory into the dentry cache.
 203                  * The same problem can affect "SUBTREECHECK" exports,
 204                  * but as nfsd_acceptable depends on correct
 205                  * access control settings being in effect, we cannot
 206                  * fix that case easily.
 207                  */
 208                 struct cred *new = prepare_creds();
 209                 if (!new)
 210                         return nfserrno(-ENOMEM);
 211                 new->cap_effective =
 212                         cap_raise_nfsd_set(new->cap_effective,
 213                                            new->cap_permitted);
 214                 put_cred(override_creds(new));
 215                 put_cred(new);
 216         } else {
 217                 error = nfsd_setuser_and_check_port(rqstp, exp);
 218                 if (error)
 219                         goto out;
 220         }
 221
 222         /*
 223          * Look up the dentry using the NFS file handle.
 224          */
 225         error = nfserr_stale;
 226         if (rqstp->rq_vers > 2)
 227                 error = nfserr_badhandle;
 228
 229         if (fh->fh_version != 1) {
 230                 sfid.i32.ino = fh->ofh_ino;
 231                 sfid.i32.gen = fh->ofh_generation;
 232                 sfid.i32.parent_ino = fh->ofh_dirino;
 233                 fid = &sfid;
 234                 data_left = 3;
 235                 if (fh->ofh_dirino == 0)
 236                         fileid_type = FILEID_INO32_GEN;
 237                 else
 238                         fileid_type = FILEID_INO32_GEN_PARENT;
 239         } else
 240                 fileid_type = fh->fh_fileid_type;
 241
 242         if (fileid_type == FILEID_ROOT)
 243                 dentry = dget(exp->ex_path.dentry);
 244         else {
 245                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 246                                 data_left, fileid_type,
 247                                 nfsd_acceptable, exp);
 248         }
 249         if (dentry == NULL)
 250                 goto out;
 251         if (IS_ERR(dentry)) {
 252                 if (PTR_ERR(dentry) != -EINVAL)
 253                         error = nfserrno(PTR_ERR(dentry));
 254                 goto out;
 255         }
 256
 257         if (S_ISDIR(dentry->d_inode->i_mode) &&
 258                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 259                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 260                                 dentry->d_parent->d_name.name, dentry->d_name.name);
 261         }
 262
 263         fhp->fh_dentry = dentry;
 264         fhp->fh_export = exp;
 265         return 0;
 266 out:
 267         exp_put(exp);
 268         return error;
 269 }
 270
 271 /**
 272  * fh_verify - filehandle lookup and access checking
 273  * @rqstp: pointer to current rpc request
 274  * @fhp: filehandle to be verified
 275  * @type: expected type of object pointed to by filehandle
 276  * @access: type of access needed to object
 277  *
 278  * Look up a dentry from the on-the-wire filehandle, check the client's
 279  * access to the export, and set the current task's credentials.
 280  *
 281  * Regardless of success or failure of fh_verify(), fh_put() should be
 282  * called on @fhp when the caller is finished with the filehandle.
 283  *
 284  * fh_verify() may be called multiple times on a given filehandle, for
 285  * example, when processing an NFSv4 compound.  The first call will look
 286  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
 287  * skip the lookup and just perform the other checks and possibly change
 288  * the current task's credentials.
 289  *
 290  * @type specifies the type of object expected using one of the S_IF*
 291  * constants defined in include/linux/stat.h.  The caller may use zero
 292  * to indicate that it doesn't care, or a negative integer to indicate
 293  * that it expects something not of the given type.
 294  *
 295  * @access is formed from the NFSD_MAY_* constants defined in
 296  * include/linux/nfsd/nfsd.h.
 297  */
 298 __be32
 299 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 300 {
 301         struct svc_export *exp;
 302         struct dentry   *dentry;
 303         __be32          error;
 304
 305         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 306
 307         if (!fhp->fh_dentry) {
 308                 error = nfsd_set_fh_dentry(rqstp, fhp);
 309                 if (error)
 310                         goto out;
 311         }
 312         dentry = fhp->fh_dentry;
 313         exp = fhp->fh_export;
 314         /*
 315          * We still have to do all these permission checks, even when
 316          * fh_dentry is already set:
 317          *      - fh_verify may be called multiple times with different
 318          *        "access" arguments (e.g. nfsd_proc_create calls
 319          *        fh_verify(...,NFSD_MAY_EXEC) first, then later (in
 320          *        nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
 321          *      - in the NFSv4 case, the filehandle may have been filled
 322          *        in by fh_compose, and given a dentry, but further
 323          *        compound operations performed with that filehandle
 324          *        still need permissions checks.  In the worst case, a
 325          *        mountpoint crossing may have changed the export
 326          *        options, and we may now need to use a different uid
 327          *        (for example, if different id-squashing options are in
 328          *        effect on the new filesystem).
 329          */
 330         error = check_pseudo_root(rqstp, dentry, exp);
 331         if (error)
 332                 goto out;
 333
 334         error = nfsd_setuser_and_check_port(rqstp, exp);
 335         if (error)
 336                 goto out;
 337
 338         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 339         if (error)
 340                 goto out;
 341
 342         /*
 343          * pseudoflavor restrictions are not enforced on NLM,
 344          * which clients virtually always use auth_sys for,
 345          * even while using RPCSEC_GSS for NFS.
 346          */
 347         if (access & NFSD_MAY_LOCK)
 348                 goto skip_pseudoflavor_check;
 349         /*
 350          * Clients may expect to be able to use auth_sys during mount,
 351          * even if they use gss for everything else; see section 2.3.2
 352          * of rfc 2623.
 353          */
 354         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 355                         && exp->ex_path.dentry == dentry)
 356                 goto skip_pseudoflavor_check;
 357
 358         error = check_nfsd_access(exp, rqstp);
 359         if (error)
 360                 goto out;
 361
 362 skip_pseudoflavor_check:
 363         /* Finally, check access permissions. */
 364         error = nfsd_permission(rqstp, exp, dentry, access);
 365
 366         if (error) {
 367                 dprintk("fh_verify: %s/%s permission failure, "
 368                         "acc=%x, error=%d\n",
 369                         dentry->d_parent->d_name.name,
 370                         dentry->d_name.name,
 371                         access, ntohl(error));
 372         }
 373 out:
 374         if (error == nfserr_stale)
 375                 nfsdstats.fh_stale++;
 376         return error;
 377 }
 378
 379
 380 /*
 381  * Compose a file handle for an NFS reply.
 382  *
 383  * Note that when first composed, the dentry may not yet have
 384  * an inode.  In this case a call to fh_update should be made
 385  * before the fh goes out on the wire ...
 386  */
 387 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 388                 struct dentry *dentry)
 389 {
 390         if (dentry != exp->ex_path.dentry) {
 391                 struct fid *fid = (struct fid *)
 392                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 393                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 394                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 395
 396                 fhp->fh_handle.fh_fileid_type =
 397                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 398                 fhp->fh_handle.fh_size += maxsize * 4;
 399         } else {
 400                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 401         }
 402 }
 403
 404 /*
 405  * for composing old style file handles
 406  */
 407 static inline void _fh_update_old(struct dentry *dentry,
 408                                   struct svc_export *exp,
 409                                   struct knfsd_fh *fh)
 410 {
 411         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 412         fh->ofh_generation = dentry->d_inode->i_generation;
 413         if (S_ISDIR(dentry->d_inode->i_mode) ||
 414             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 415                 fh->ofh_dirino = 0;
 416 }
 417
 418 static bool is_root_export(struct svc_export *exp)
 419 {
 420         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 421 }
 422
 423 static struct super_block *exp_sb(struct svc_export *exp)
 424 {
 425         return exp->ex_path.dentry->d_inode->i_sb;
 426 }
 427
 428 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 429 {
 430         switch (fsid_type) {
 431         case FSID_DEV:
 432                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 433                         return 0;
 434                 /* FALL THROUGH */
 435         case FSID_MAJOR_MINOR:
 436         case FSID_ENCODE_DEV:
 437                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 438         case FSID_NUM:
 439                 return exp->ex_flags & NFSEXP_FSID;
 440         case FSID_UUID8:
 441         case FSID_UUID16:
 442                 if (!is_root_export(exp))
 443                         return 0;
 444                 /* fall through */
 445         case FSID_UUID4_INUM:
 446         case FSID_UUID16_INUM:
 447                 return exp->ex_uuid != NULL;
 448         }
 449         return 1;
 450 }
 451
 452
 453 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 454 {
 455         u8 version;
 456         u8 fsid_type;
 457 retry:
 458         version = 1;
 459         if (ref_fh && ref_fh->fh_export == exp) {
 460                 version = ref_fh->fh_handle.fh_version;
 461                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 462
 463                 ref_fh = NULL;
 464
 465                 switch (version) {
 466                 case 0xca:
 467                         fsid_type = FSID_DEV;
 468                         break;
 469                 case 1:
 470                         break;
 471                 default:
 472                         goto retry;
 473                 }
 474
 475                 /*
 476                  * As the fsid -> filesystem mapping was guided by
 477                  * user-space, there is no guarantee that the filesystem
 478                  * actually supports that fsid type. If it doesn't we
 479                  * loop around again without ref_fh set.
 480                  */
 481                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 482                         goto retry;
 483         } else if (exp->ex_flags & NFSEXP_FSID) {
 484                 fsid_type = FSID_NUM;
 485         } else if (exp->ex_uuid) {
 486                 if (fhp->fh_maxsize >= 64) {
 487                         if (is_root_export(exp))
 488                                 fsid_type = FSID_UUID16;
 489                         else
 490                                 fsid_type = FSID_UUID16_INUM;
 491                 } else {
 492                         if (is_root_export(exp))
 493                                 fsid_type = FSID_UUID8;
 494                         else
 495                                 fsid_type = FSID_UUID4_INUM;
 496                 }
 497         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 498                 /* for newer device numbers, we must use a newer fsid format */
 499                 fsid_type = FSID_ENCODE_DEV;
 500         else
 501                 fsid_type = FSID_DEV;
 502         fhp->fh_handle.fh_version = version;
 503         if (version)
 504                 fhp->fh_handle.fh_fsid_type = fsid_type;
 505 }
 506
 507 __be32
 508 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 509            struct svc_fh *ref_fh)
 510 {
 511         /* ref_fh is a reference file handle.
 512          * if it is non-null and for the same filesystem, then we should compose
 513          * a filehandle which is of the same version, where possible.
 514          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 515          * Then create a 32byte filehandle using nfs_fhbase_old
 516          *
 517          */
 518
 519         struct inode * inode = dentry->d_inode;
 520         struct dentry *parent = dentry->d_parent;
 521         __u32 *datap;
 522         dev_t ex_dev = exp_sb(exp)->s_dev;
 523
 524         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 525                 MAJOR(ex_dev), MINOR(ex_dev),
 526                 (long) exp->ex_path.dentry->d_inode->i_ino,
 527                 parent->d_name.name, dentry->d_name.name,
 528                 (inode ? inode->i_ino : 0));
 529
 530         /* Choose filehandle version and fsid type based on
 531          * the reference filehandle (if it is in the same export)
 532          * or the export options.
 533          */
 534          set_version_and_fsid_type(fhp, exp, ref_fh);
 535
 536         if (ref_fh == fhp)
 537                 fh_put(ref_fh);
 538
 539         if (fhp->fh_locked || fhp->fh_dentry) {
 540                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 541                        parent->d_name.name, dentry->d_name.name);
 542         }
 543         if (fhp->fh_maxsize < NFS_FHSIZE)
 544                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 545                        fhp->fh_maxsize,
 546                        parent->d_name.name, dentry->d_name.name);
 547
 548         fhp->fh_dentry = dget(dentry); /* our internal copy */
 549         fhp->fh_export = exp;
 550         cache_get(&exp->h);
 551
 552         if (fhp->fh_handle.fh_version == 0xca) {
 553                 /* old style filehandle please */
 554                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 555                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 556                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 557                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 558                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 559                 fhp->fh_handle.ofh_xino =
 560                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 561                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 562                 if (inode)
 563                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 564         } else {
 565                 int len;
 566                 fhp->fh_handle.fh_auth_type = 0;
 567                 datap = fhp->fh_handle.fh_auth+0;
 568                 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
 569                         exp->ex_path.dentry->d_inode->i_ino,
 570                         exp->ex_fsid, exp->ex_uuid);
 571
 572                 len = key_len(fhp->fh_handle.fh_fsid_type);
 573                 datap += len/4;
 574                 fhp->fh_handle.fh_size = 4 + len;
 575
 576                 if (inode)
 577                         _fh_update(fhp, exp, dentry);
 578                 if (fhp->fh_handle.fh_fileid_type == 255) {
 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 (!dentry->d_inode)
 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                         goto out;
 607
 608                 _fh_update(fhp, fhp->fh_export, dentry);
 609                 if (fhp->fh_handle.fh_fileid_type == 255)
 610                         return nfserr_opnotsupp;
 611         }
 612 out:
 613         return 0;
 614
 615 out_bad:
 616         printk(KERN_ERR "fh_update: fh not verified!\n");
 617         goto out;
 618 out_negative:
 619         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 620                 dentry->d_parent->d_name.name, dentry->d_name.name);
 621         goto out;
 622 }
 623
 624 /*
 625  * Release a file handle.
 626  */
 627 void
 628 fh_put(struct svc_fh *fhp)
 629 {
 630         struct dentry * dentry = fhp->fh_dentry;
 631         struct svc_export * exp = fhp->fh_export;
 632         if (dentry) {
 633                 fh_unlock(fhp);
 634                 fhp->fh_dentry = NULL;
 635                 dput(dentry);
 636 #ifdef CONFIG_NFSD_V3
 637                 fhp->fh_pre_saved = 0;
 638                 fhp->fh_post_saved = 0;
 639 #endif
 640         }
 641         if (exp) {
 642                 cache_put(&exp->h, &svc_export_cache);
 643                 fhp->fh_export = NULL;
 644         }
 645         return;
 646 }
 647
 648 /*
 649  * Shorthand for dprintk()'s
 650  */
 651 char * SVCFH_fmt(struct svc_fh *fhp)
 652 {
 653         struct knfsd_fh *fh = &fhp->fh_handle;
 654
 655         static char buf[80];
 656         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 657                 fh->fh_size,
 658                 fh->fh_base.fh_pad[0],
 659                 fh->fh_base.fh_pad[1],
 660                 fh->fh_base.fh_pad[2],
 661                 fh->fh_base.fh_pad[3],
 662                 fh->fh_base.fh_pad[4],
 663                 fh->fh_base.fh_pad[5]);
 664         return buf;
 665 }
 666
 667 enum fsid_source fsid_source(struct svc_fh *fhp)
 668 {
 669         if (fhp->fh_handle.fh_version != 1)
 670                 return FSIDSOURCE_DEV;
 671         switch(fhp->fh_handle.fh_fsid_type) {
 672         case FSID_DEV:
 673         case FSID_ENCODE_DEV:
 674         case FSID_MAJOR_MINOR:
 675                 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 676                         return FSIDSOURCE_DEV;
 677                 break;
 678         case FSID_NUM:
 679                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 680                         return FSIDSOURCE_FSID;
 681                 break;
 682         default:
 683                 break;
 684         }
 685         /* either a UUID type filehandle, or the filehandle doesn't
 686          * match the export.
 687          */
 688         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 689                 return FSIDSOURCE_FSID;
 690         if (fhp->fh_export->ex_uuid)
 691                 return FSIDSOURCE_UUID;
 692         return FSIDSOURCE_DEV;
 693 }