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("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(!S_ISDIR(dentry->d_inode->i_mode) &&
 118                      !S_ISLNK(dentry->d_inode->i_mode)))
 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                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 166                         fh->fh_fsid[1] = fh->fh_fsid[2];
 167                 }
 168                 data_left -= len;
 169                 if (data_left < 0)
 170                         return error;
 171                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
 172                 fid = (struct fid *)(fh->fh_fsid + len);
 173         } else {
 174                 __u32 tfh[2];
 175                 dev_t xdev;
 176                 ino_t xino;
 177
 178                 if (fh->fh_size != NFS_FHSIZE)
 179                         return error;
 180                 /* assume old filehandle format */
 181                 xdev = old_decode_dev(fh->ofh_xdev);
 182                 xino = u32_to_ino_t(fh->ofh_xino);
 183                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 184                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 185         }
 186
 187         error = nfserr_stale;
 188         if (PTR_ERR(exp) == -ENOENT)
 189                 return error;
 190
 191         if (IS_ERR(exp))
 192                 return nfserrno(PTR_ERR(exp));
 193
 194         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 195                 /* Elevate privileges so that the lack of 'r' or 'x'
 196                  * permission on some parent directory will
 197                  * not stop exportfs_decode_fh from being able
 198                  * to reconnect a directory into the dentry cache.
 199                  * The same problem can affect "SUBTREECHECK" exports,
 200                  * but as nfsd_acceptable depends on correct
 201                  * access control settings being in effect, we cannot
 202                  * fix that case easily.
 203                  */
 204                 struct cred *new = prepare_creds();
 205                 if (!new)
 206                         return nfserrno(-ENOMEM);
 207                 new->cap_effective =
 208                         cap_raise_nfsd_set(new->cap_effective,
 209                                            new->cap_permitted);
 210                 put_cred(override_creds(new));
 211                 put_cred(new);
 212         } else {
 213                 error = nfsd_setuser_and_check_port(rqstp, exp);
 214                 if (error)
 215                         goto out;
 216         }
 217
 218         /*
 219          * Look up the dentry using the NFS file handle.
 220          */
 221         error = nfserr_stale;
 222         if (rqstp->rq_vers > 2)
 223                 error = nfserr_badhandle;
 224
 225         if (fh->fh_version != 1) {
 226                 sfid.i32.ino = fh->ofh_ino;
 227                 sfid.i32.gen = fh->ofh_generation;
 228                 sfid.i32.parent_ino = fh->ofh_dirino;
 229                 fid = &sfid;
 230                 data_left = 3;
 231                 if (fh->ofh_dirino == 0)
 232                         fileid_type = FILEID_INO32_GEN;
 233                 else
 234                         fileid_type = FILEID_INO32_GEN_PARENT;
 235         } else
 236                 fileid_type = fh->fh_fileid_type;
 237
 238         if (fileid_type == FILEID_ROOT)
 239                 dentry = dget(exp->ex_path.dentry);
 240         else {
 241                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 242                                 data_left, fileid_type,
 243                                 nfsd_acceptable, exp);
 244         }
 245         if (dentry == NULL)
 246                 goto out;
 247         if (IS_ERR(dentry)) {
 248                 if (PTR_ERR(dentry) != -EINVAL)
 249                         error = nfserrno(PTR_ERR(dentry));
 250                 goto out;
 251         }
 252
 253         if (S_ISDIR(dentry->d_inode->i_mode) &&
 254                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 255                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
 256                                 dentry);
 257         }
 258
 259         fhp->fh_dentry = dentry;
 260         fhp->fh_export = exp;
 261         return 0;
 262 out:
 263         exp_put(exp);
 264         return error;
 265 }
 266
 267 /**
 268  * fh_verify - filehandle lookup and access checking
 269  * @rqstp: pointer to current rpc request
 270  * @fhp: filehandle to be verified
 271  * @type: expected type of object pointed to by filehandle
 272  * @access: type of access needed to object
 273  *
 274  * Look up a dentry from the on-the-wire filehandle, check the client's
 275  * access to the export, and set the current task's credentials.
 276  *
 277  * Regardless of success or failure of fh_verify(), fh_put() should be
 278  * called on @fhp when the caller is finished with the filehandle.
 279  *
 280  * fh_verify() may be called multiple times on a given filehandle, for
 281  * example, when processing an NFSv4 compound.  The first call will look
 282  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
 283  * skip the lookup and just perform the other checks and possibly change
 284  * the current task's credentials.
 285  *
 286  * @type specifies the type of object expected using one of the S_IF*
 287  * constants defined in include/linux/stat.h.  The caller may use zero
 288  * to indicate that it doesn't care, or a negative integer to indicate
 289  * that it expects something not of the given type.
 290  *
 291  * @access is formed from the NFSD_MAY_* constants defined in
 292  * include/linux/nfsd/nfsd.h.
 293  */
 294 __be32
 295 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
 296 {
 297         struct svc_export *exp;
 298         struct dentry   *dentry;
 299         __be32          error;
 300
 301         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 302
 303         if (!fhp->fh_dentry) {
 304                 error = nfsd_set_fh_dentry(rqstp, fhp);
 305                 if (error)
 306                         goto out;
 307         }
 308         dentry = fhp->fh_dentry;
 309         exp = fhp->fh_export;
 310         /*
 311          * We still have to do all these permission checks, even when
 312          * fh_dentry is already set:
 313          *      - fh_verify may be called multiple times with different
 314          *        "access" arguments (e.g. nfsd_proc_create calls
 315          *        fh_verify(...,NFSD_MAY_EXEC) first, then later (in
 316          *        nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
 317          *      - in the NFSv4 case, the filehandle may have been filled
 318          *        in by fh_compose, and given a dentry, but further
 319          *        compound operations performed with that filehandle
 320          *        still need permissions checks.  In the worst case, a
 321          *        mountpoint crossing may have changed the export
 322          *        options, and we may now need to use a different uid
 323          *        (for example, if different id-squashing options are in
 324          *        effect on the new filesystem).
 325          */
 326         error = check_pseudo_root(rqstp, dentry, exp);
 327         if (error)
 328                 goto out;
 329
 330         error = nfsd_setuser_and_check_port(rqstp, exp);
 331         if (error)
 332                 goto out;
 333
 334         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 335         if (error)
 336                 goto out;
 337
 338         /*
 339          * pseudoflavor restrictions are not enforced on NLM,
 340          * which clients virtually always use auth_sys for,
 341          * even while using RPCSEC_GSS for NFS.
 342          */
 343         if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
 344                 goto skip_pseudoflavor_check;
 345         /*
 346          * Clients may expect to be able to use auth_sys during mount,
 347          * even if they use gss for everything else; see section 2.3.2
 348          * of rfc 2623.
 349          */
 350         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 351                         && exp->ex_path.dentry == dentry)
 352                 goto skip_pseudoflavor_check;
 353
 354         error = check_nfsd_access(exp, rqstp);
 355         if (error)
 356                 goto out;
 357
 358 skip_pseudoflavor_check:
 359         /* Finally, check access permissions. */
 360         error = nfsd_permission(rqstp, exp, dentry, access);
 361
 362         if (error) {
 363                 dprintk("fh_verify: %pd2 permission failure, "
 364                         "acc=%x, error=%d\n",
 365                         dentry,
 366                         access, ntohl(error));
 367         }
 368 out:
 369         if (error == nfserr_stale)
 370                 nfsdstats.fh_stale++;
 371         return error;
 372 }
 373
 374
 375 /*
 376  * Compose a file handle for an NFS reply.
 377  *
 378  * Note that when first composed, the dentry may not yet have
 379  * an inode.  In this case a call to fh_update should be made
 380  * before the fh goes out on the wire ...
 381  */
 382 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 383                 struct dentry *dentry)
 384 {
 385         if (dentry != exp->ex_path.dentry) {
 386                 struct fid *fid = (struct fid *)
 387                         (fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
 388                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 389                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 390
 391                 fhp->fh_handle.fh_fileid_type =
 392                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 393                 fhp->fh_handle.fh_size += maxsize * 4;
 394         } else {
 395                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 396         }
 397 }
 398
 399 /*
 400  * for composing old style file handles
 401  */
 402 static inline void _fh_update_old(struct dentry *dentry,
 403                                   struct svc_export *exp,
 404                                   struct knfsd_fh *fh)
 405 {
 406         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 407         fh->ofh_generation = dentry->d_inode->i_generation;
 408         if (S_ISDIR(dentry->d_inode->i_mode) ||
 409             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 410                 fh->ofh_dirino = 0;
 411 }
 412
 413 static bool is_root_export(struct svc_export *exp)
 414 {
 415         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 416 }
 417
 418 static struct super_block *exp_sb(struct svc_export *exp)
 419 {
 420         return exp->ex_path.dentry->d_inode->i_sb;
 421 }
 422
 423 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 424 {
 425         switch (fsid_type) {
 426         case FSID_DEV:
 427                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 428                         return 0;
 429                 /* FALL THROUGH */
 430         case FSID_MAJOR_MINOR:
 431         case FSID_ENCODE_DEV:
 432                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 433         case FSID_NUM:
 434                 return exp->ex_flags & NFSEXP_FSID;
 435         case FSID_UUID8:
 436         case FSID_UUID16:
 437                 if (!is_root_export(exp))
 438                         return 0;
 439                 /* fall through */
 440         case FSID_UUID4_INUM:
 441         case FSID_UUID16_INUM:
 442                 return exp->ex_uuid != NULL;
 443         }
 444         return 1;
 445 }
 446
 447
 448 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 449 {
 450         u8 version;
 451         u8 fsid_type;
 452 retry:
 453         version = 1;
 454         if (ref_fh && ref_fh->fh_export == exp) {
 455                 version = ref_fh->fh_handle.fh_version;
 456                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 457
 458                 ref_fh = NULL;
 459
 460                 switch (version) {
 461                 case 0xca:
 462                         fsid_type = FSID_DEV;
 463                         break;
 464                 case 1:
 465                         break;
 466                 default:
 467                         goto retry;
 468                 }
 469
 470                 /*
 471                  * As the fsid -> filesystem mapping was guided by
 472                  * user-space, there is no guarantee that the filesystem
 473                  * actually supports that fsid type. If it doesn't we
 474                  * loop around again without ref_fh set.
 475                  */
 476                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 477                         goto retry;
 478         } else if (exp->ex_flags & NFSEXP_FSID) {
 479                 fsid_type = FSID_NUM;
 480         } else if (exp->ex_uuid) {
 481                 if (fhp->fh_maxsize >= 64) {
 482                         if (is_root_export(exp))
 483                                 fsid_type = FSID_UUID16;
 484                         else
 485                                 fsid_type = FSID_UUID16_INUM;
 486                 } else {
 487                         if (is_root_export(exp))
 488                                 fsid_type = FSID_UUID8;
 489                         else
 490                                 fsid_type = FSID_UUID4_INUM;
 491                 }
 492         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 493                 /* for newer device numbers, we must use a newer fsid format */
 494                 fsid_type = FSID_ENCODE_DEV;
 495         else
 496                 fsid_type = FSID_DEV;
 497         fhp->fh_handle.fh_version = version;
 498         if (version)
 499                 fhp->fh_handle.fh_fsid_type = fsid_type;
 500 }
 501
 502 __be32
 503 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 504            struct svc_fh *ref_fh)
 505 {
 506         /* ref_fh is a reference file handle.
 507          * if it is non-null and for the same filesystem, then we should compose
 508          * a filehandle which is of the same version, where possible.
 509          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 510          * Then create a 32byte filehandle using nfs_fhbase_old
 511          *
 512          */
 513
 514         struct inode * inode = dentry->d_inode;
 515         dev_t ex_dev = exp_sb(exp)->s_dev;
 516
 517         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
 518                 MAJOR(ex_dev), MINOR(ex_dev),
 519                 (long) exp->ex_path.dentry->d_inode->i_ino,
 520                 dentry,
 521                 (inode ? inode->i_ino : 0));
 522
 523         /* Choose filehandle version and fsid type based on
 524          * the reference filehandle (if it is in the same export)
 525          * or the export options.
 526          */
 527          set_version_and_fsid_type(fhp, exp, ref_fh);
 528
 529         if (ref_fh == fhp)
 530                 fh_put(ref_fh);
 531
 532         if (fhp->fh_locked || fhp->fh_dentry) {
 533                 printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
 534                        dentry);
 535         }
 536         if (fhp->fh_maxsize < NFS_FHSIZE)
 537                 printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
 538                        fhp->fh_maxsize,
 539                        dentry);
 540
 541         fhp->fh_dentry = dget(dentry); /* our internal copy */
 542         fhp->fh_export = exp;
 543         cache_get(&exp->h);
 544
 545         if (fhp->fh_handle.fh_version == 0xca) {
 546                 /* old style filehandle please */
 547                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 548                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 549                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 550                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 551                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 552                 fhp->fh_handle.ofh_xino =
 553                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 554                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 555                 if (inode)
 556                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 557         } else {
 558                 fhp->fh_handle.fh_size =
 559                         key_len(fhp->fh_handle.fh_fsid_type) + 4;
 560                 fhp->fh_handle.fh_auth_type = 0;
 561
 562                 mk_fsid(fhp->fh_handle.fh_fsid_type,
 563                         fhp->fh_handle.fh_fsid,
 564                         ex_dev,
 565                         exp->ex_path.dentry->d_inode->i_ino,
 566                         exp->ex_fsid, exp->ex_uuid);
 567
 568                 if (inode)
 569                         _fh_update(fhp, exp, dentry);
 570                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
 571                         fh_put(fhp);
 572                         return nfserr_opnotsupp;
 573                 }
 574         }
 575
 576         return 0;
 577 }
 578
 579 /*
 580  * Update file handle information after changing a dentry.
 581  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 582  */
 583 __be32
 584 fh_update(struct svc_fh *fhp)
 585 {
 586         struct dentry *dentry;
 587
 588         if (!fhp->fh_dentry)
 589                 goto out_bad;
 590
 591         dentry = fhp->fh_dentry;
 592         if (!dentry->d_inode)
 593                 goto out_negative;
 594         if (fhp->fh_handle.fh_version != 1) {
 595                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 596         } else {
 597                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 598                         return 0;
 599
 600                 _fh_update(fhp, fhp->fh_export, dentry);
 601                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
 602                         return nfserr_opnotsupp;
 603         }
 604         return 0;
 605 out_bad:
 606         printk(KERN_ERR "fh_update: fh not verified!\n");
 607         return nfserr_serverfault;
 608 out_negative:
 609         printk(KERN_ERR "fh_update: %pd2 still negative!\n",
 610                 dentry);
 611         return nfserr_serverfault;
 612 }
 613
 614 /*
 615  * Release a file handle.
 616  */
 617 void
 618 fh_put(struct svc_fh *fhp)
 619 {
 620         struct dentry * dentry = fhp->fh_dentry;
 621         struct svc_export * exp = fhp->fh_export;
 622         if (dentry) {
 623                 fh_unlock(fhp);
 624                 fhp->fh_dentry = NULL;
 625                 dput(dentry);
 626 #ifdef CONFIG_NFSD_V3
 627                 fhp->fh_pre_saved = 0;
 628                 fhp->fh_post_saved = 0;
 629 #endif
 630         }
 631         fh_drop_write(fhp);
 632         if (exp) {
 633                 exp_put(exp);
 634                 fhp->fh_export = NULL;
 635         }
 636         return;
 637 }
 638
 639 /*
 640  * Shorthand for dprintk()'s
 641  */
 642 char * SVCFH_fmt(struct svc_fh *fhp)
 643 {
 644         struct knfsd_fh *fh = &fhp->fh_handle;
 645
 646         static char buf[80];
 647         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 648                 fh->fh_size,
 649                 fh->fh_base.fh_pad[0],
 650                 fh->fh_base.fh_pad[1],
 651                 fh->fh_base.fh_pad[2],
 652                 fh->fh_base.fh_pad[3],
 653                 fh->fh_base.fh_pad[4],
 654                 fh->fh_base.fh_pad[5]);
 655         return buf;
 656 }
 657
 658 enum fsid_source fsid_source(struct svc_fh *fhp)
 659 {
 660         if (fhp->fh_handle.fh_version != 1)
 661                 return FSIDSOURCE_DEV;
 662         switch(fhp->fh_handle.fh_fsid_type) {
 663         case FSID_DEV:
 664         case FSID_ENCODE_DEV:
 665         case FSID_MAJOR_MINOR:
 666                 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 667                         return FSIDSOURCE_DEV;
 668                 break;
 669         case FSID_NUM:
 670                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 671                         return FSIDSOURCE_FSID;
 672                 break;
 673         default:
 674                 break;
 675         }
 676         /* either a UUID type filehandle, or the filehandle doesn't
 677          * match the export.
 678          */
 679         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 680                 return FSIDSOURCE_FSID;
 681         if (fhp->fh_export->ex_uuid)
 682                 return FSIDSOURCE_UUID;
 683         return FSIDSOURCE_DEV;
 684 }