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         if (type > 0 && (mode & S_IFMT) != type) {
  65                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  66                         return nfserr_symlink;
  67                 else if (type == S_IFDIR)
  68                         return nfserr_notdir;
  69                 else if ((mode & S_IFMT) == S_IFDIR)
  70                         return nfserr_isdir;
  71                 else
  72                         return nfserr_inval;
  73         }
  74         return 0;
  75 }
  76
  77 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
  78                                           struct svc_export *exp)
  79 {
  80         int flags = nfsexp_flags(rqstp, exp);
  81
  82         /* Check if the request originated from a secure port. */
  83         if (!rqstp->rq_secure && !(flags & NFSEXP_INSECURE_PORT)) {
  84                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
  85                 dprintk(KERN_WARNING
  86                        "nfsd: request from insecure port %s!\n",
  87                        svc_print_addr(rqstp, buf, sizeof(buf)));
  88                 return nfserr_perm;
  89         }
  90
  91         /* Set user creds for this exportpoint */
  92         return nfserrno(nfsd_setuser(rqstp, exp));
  93 }
  94
  95 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
  96         struct dentry *dentry, struct svc_export *exp)
  97 {
  98         if (!(exp->ex_flags & NFSEXP_V4ROOT))
  99                 return nfs_ok;
 100         /*
 101          * v2/v3 clients have no need for the V4ROOT export--they use
 102          * the mount protocl instead; also, further V4ROOT checks may be
 103          * in v4-specific code, in which case v2/v3 clients could bypass
 104          * them.
 105          */
 106         if (!nfsd_v4client(rqstp))
 107                 return nfserr_stale;
 108         /*
 109          * We're exposing only the directories and symlinks that have to be
 110          * traversed on the way to real exports:
 111          */
 112         if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
 113                      !S_ISLNK(dentry->d_inode->i_mode)))
 114                 return nfserr_stale;
 115         /*
 116          * A pseudoroot export gives permission to access only one
 117          * single directory; the kernel has to make another upcall
 118          * before granting access to anything else under it:
 119          */
 120         if (unlikely(dentry != exp->ex_path.dentry))
 121                 return nfserr_stale;
 122         return nfs_ok;
 123 }
 124
 125 /*
 126  * Use the given filehandle to look up the corresponding export and
 127  * dentry.  On success, the results are used to set fh_export and
 128  * fh_dentry.
 129  */
 130 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 131 {
 132         struct knfsd_fh *fh = &fhp->fh_handle;
 133         struct fid *fid = NULL, sfid;
 134         struct svc_export *exp;
 135         struct dentry *dentry;
 136         int fileid_type;
 137         int data_left = fh->fh_size/4;
 138         __be32 error;
 139
 140         error = nfserr_stale;
 141         if (rqstp->rq_vers > 2)
 142                 error = nfserr_badhandle;
 143         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 144                 return nfserr_nofilehandle;
 145
 146         if (fh->fh_version == 1) {
 147                 int len;
 148
 149                 if (--data_left < 0)
 150                         return error;
 151                 if (fh->fh_auth_type != 0)
 152                         return error;
 153                 len = key_len(fh->fh_fsid_type) / 4;
 154                 if (len == 0)
 155                         return error;
 156                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 157                         /* deprecated, convert to type 3 */
 158                         len = key_len(FSID_ENCODE_DEV)/4;
 159                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 160                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 161                         fh->fh_fsid[1] = fh->fh_fsid[2];
 162                 }
 163                 data_left -= len;
 164                 if (data_left < 0)
 165                         return error;
 166                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
 167                 fid = (struct fid *)(fh->fh_auth + len);
 168         } else {
 169                 __u32 tfh[2];
 170                 dev_t xdev;
 171                 ino_t xino;
 172
 173                 if (fh->fh_size != NFS_FHSIZE)
 174                         return error;
 175                 /* assume old filehandle format */
 176                 xdev = old_decode_dev(fh->ofh_xdev);
 177                 xino = u32_to_ino_t(fh->ofh_xino);
 178                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 179                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 180         }
 181
 182         error = nfserr_stale;
 183         if (PTR_ERR(exp) == -ENOENT)
 184                 return error;
 185
 186         if (IS_ERR(exp))
 187                 return nfserrno(PTR_ERR(exp));
 188
 189         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 190                 /* Elevate privileges so that the lack of 'r' or 'x'
 191                  * permission on some parent directory will
 192                  * not stop exportfs_decode_fh from being able
 193                  * to reconnect a directory into the dentry cache.
 194                  * The same problem can affect "SUBTREECHECK" exports,
 195                  * but as nfsd_acceptable depends on correct
 196                  * access control settings being in effect, we cannot
 197                  * fix that case easily.
 198                  */
 199                 struct cred *new = prepare_creds();
 200                 if (!new)
 201                         return nfserrno(-ENOMEM);
 202                 new->cap_effective =
 203                         cap_raise_nfsd_set(new->cap_effective,
 204                                            new->cap_permitted);
 205                 put_cred(override_creds(new));
 206                 put_cred(new);
 207         } else {
 208                 error = nfsd_setuser_and_check_port(rqstp, exp);
 209                 if (error)
 210                         goto out;
 211         }
 212
 213         /*
 214          * Look up the dentry using the NFS file handle.
 215          */
 216         error = nfserr_stale;
 217         if (rqstp->rq_vers > 2)
 218                 error = nfserr_badhandle;
 219
 220         if (fh->fh_version != 1) {
 221                 sfid.i32.ino = fh->ofh_ino;
 222                 sfid.i32.gen = fh->ofh_generation;
 223                 sfid.i32.parent_ino = fh->ofh_dirino;
 224                 fid = &sfid;
 225                 data_left = 3;
 226                 if (fh->ofh_dirino == 0)
 227                         fileid_type = FILEID_INO32_GEN;
 228                 else
 229                         fileid_type = FILEID_INO32_GEN_PARENT;
 230         } else
 231                 fileid_type = fh->fh_fileid_type;
 232
 233         if (fileid_type == FILEID_ROOT)
 234                 dentry = dget(exp->ex_path.dentry);
 235         else {
 236                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 237                                 data_left, fileid_type,
 238                                 nfsd_acceptable, exp);
 239         }
 240         if (dentry == NULL)
 241                 goto out;
 242         if (IS_ERR(dentry)) {
 243                 if (PTR_ERR(dentry) != -EINVAL)
 244                         error = nfserrno(PTR_ERR(dentry));
 245                 goto out;
 246         }
 247
 248         if (S_ISDIR(dentry->d_inode->i_mode) &&
 249                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 250                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 251                                 dentry->d_parent->d_name.name, dentry->d_name.name);
 252         }
 253
 254         fhp->fh_dentry = dentry;
 255         fhp->fh_export = exp;
 256         return 0;
 257 out:
 258         exp_put(exp);
 259         return error;
 260 }
 261
 262 /**
 263  * fh_verify - filehandle lookup and access checking
 264  * @rqstp: pointer to current rpc request
 265  * @fhp: filehandle to be verified
 266  * @type: expected type of object pointed to by filehandle
 267  * @access: type of access needed to object
 268  *
 269  * Look up a dentry from the on-the-wire filehandle, check the client's
 270  * access to the export, and set the current task's credentials.
 271  *
 272  * Regardless of success or failure of fh_verify(), fh_put() should be
 273  * called on @fhp when the caller is finished with the filehandle.
 274  *
 275  * fh_verify() may be called multiple times on a given filehandle, for
 276  * example, when processing an NFSv4 compound.  The first call will look
 277  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
 278  * skip the lookup and just perform the other checks and possibly change
 279  * the current task's credentials.
 280  *
 281  * @type specifies the type of object expected using one of the S_IF*
 282  * constants defined in include/linux/stat.h.  The caller may use zero
 283  * to indicate that it doesn't care, or a negative integer to indicate
 284  * that it expects something not of the given type.
 285  *
 286  * @access is formed from the NFSD_MAY_* constants defined in
 287  * include/linux/nfsd/nfsd.h.
 288  */
 289 __be32
 290 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 291 {
 292         struct svc_export *exp;
 293         struct dentry   *dentry;
 294         __be32          error;
 295
 296         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 297
 298         if (!fhp->fh_dentry) {
 299                 error = nfsd_set_fh_dentry(rqstp, fhp);
 300                 if (error)
 301                         goto out;
 302         }
 303         dentry = fhp->fh_dentry;
 304         exp = fhp->fh_export;
 305         /*
 306          * We still have to do all these permission checks, even when
 307          * fh_dentry is already set:
 308          *      - fh_verify may be called multiple times with different
 309          *        "access" arguments (e.g. nfsd_proc_create calls
 310          *        fh_verify(...,NFSD_MAY_EXEC) first, then later (in
 311          *        nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
 312          *      - in the NFSv4 case, the filehandle may have been filled
 313          *        in by fh_compose, and given a dentry, but further
 314          *        compound operations performed with that filehandle
 315          *        still need permissions checks.  In the worst case, a
 316          *        mountpoint crossing may have changed the export
 317          *        options, and we may now need to use a different uid
 318          *        (for example, if different id-squashing options are in
 319          *        effect on the new filesystem).
 320          */
 321         error = check_pseudo_root(rqstp, dentry, exp);
 322         if (error)
 323                 goto out;
 324
 325         error = nfsd_setuser_and_check_port(rqstp, exp);
 326         if (error)
 327                 goto out;
 328
 329         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 330         if (error)
 331                 goto out;
 332
 333         /*
 334          * pseudoflavor restrictions are not enforced on NLM,
 335          * which clients virtually always use auth_sys for,
 336          * even while using RPCSEC_GSS for NFS.
 337          */
 338         if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
 339                 goto skip_pseudoflavor_check;
 340         /*
 341          * Clients may expect to be able to use auth_sys during mount,
 342          * even if they use gss for everything else; see section 2.3.2
 343          * of rfc 2623.
 344          */
 345         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 346                         && exp->ex_path.dentry == dentry)
 347                 goto skip_pseudoflavor_check;
 348
 349         error = check_nfsd_access(exp, rqstp);
 350         if (error)
 351                 goto out;
 352
 353 skip_pseudoflavor_check:
 354         /* Finally, check access permissions. */
 355         error = nfsd_permission(rqstp, exp, dentry, access);
 356
 357         if (error) {
 358                 dprintk("fh_verify: %s/%s permission failure, "
 359                         "acc=%x, error=%d\n",
 360                         dentry->d_parent->d_name.name,
 361                         dentry->d_name.name,
 362                         access, ntohl(error));
 363         }
 364 out:
 365         if (error == nfserr_stale)
 366                 nfsdstats.fh_stale++;
 367         return error;
 368 }
 369
 370
 371 /*
 372  * Compose a file handle for an NFS reply.
 373  *
 374  * Note that when first composed, the dentry may not yet have
 375  * an inode.  In this case a call to fh_update should be made
 376  * before the fh goes out on the wire ...
 377  */
 378 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 379                 struct dentry *dentry)
 380 {
 381         if (dentry != exp->ex_path.dentry) {
 382                 struct fid *fid = (struct fid *)
 383                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 384                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 385                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 386
 387                 fhp->fh_handle.fh_fileid_type =
 388                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 389                 fhp->fh_handle.fh_size += maxsize * 4;
 390         } else {
 391                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 392         }
 393 }
 394
 395 /*
 396  * for composing old style file handles
 397  */
 398 static inline void _fh_update_old(struct dentry *dentry,
 399                                   struct svc_export *exp,
 400                                   struct knfsd_fh *fh)
 401 {
 402         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 403         fh->ofh_generation = dentry->d_inode->i_generation;
 404         if (S_ISDIR(dentry->d_inode->i_mode) ||
 405             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 406                 fh->ofh_dirino = 0;
 407 }
 408
 409 static bool is_root_export(struct svc_export *exp)
 410 {
 411         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 412 }
 413
 414 static struct super_block *exp_sb(struct svc_export *exp)
 415 {
 416         return exp->ex_path.dentry->d_inode->i_sb;
 417 }
 418
 419 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 420 {
 421         switch (fsid_type) {
 422         case FSID_DEV:
 423                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 424                         return 0;
 425                 /* FALL THROUGH */
 426         case FSID_MAJOR_MINOR:
 427         case FSID_ENCODE_DEV:
 428                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 429         case FSID_NUM:
 430                 return exp->ex_flags & NFSEXP_FSID;
 431         case FSID_UUID8:
 432         case FSID_UUID16:
 433                 if (!is_root_export(exp))
 434                         return 0;
 435                 /* fall through */
 436         case FSID_UUID4_INUM:
 437         case FSID_UUID16_INUM:
 438                 return exp->ex_uuid != NULL;
 439         }
 440         return 1;
 441 }
 442
 443
 444 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 445 {
 446         u8 version;
 447         u8 fsid_type;
 448 retry:
 449         version = 1;
 450         if (ref_fh && ref_fh->fh_export == exp) {
 451                 version = ref_fh->fh_handle.fh_version;
 452                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 453
 454                 ref_fh = NULL;
 455
 456                 switch (version) {
 457                 case 0xca:
 458                         fsid_type = FSID_DEV;
 459                         break;
 460                 case 1:
 461                         break;
 462                 default:
 463                         goto retry;
 464                 }
 465
 466                 /*
 467                  * As the fsid -> filesystem mapping was guided by
 468                  * user-space, there is no guarantee that the filesystem
 469                  * actually supports that fsid type. If it doesn't we
 470                  * loop around again without ref_fh set.
 471                  */
 472                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 473                         goto retry;
 474         } else if (exp->ex_flags & NFSEXP_FSID) {
 475                 fsid_type = FSID_NUM;
 476         } else if (exp->ex_uuid) {
 477                 if (fhp->fh_maxsize >= 64) {
 478                         if (is_root_export(exp))
 479                                 fsid_type = FSID_UUID16;
 480                         else
 481                                 fsid_type = FSID_UUID16_INUM;
 482                 } else {
 483                         if (is_root_export(exp))
 484                                 fsid_type = FSID_UUID8;
 485                         else
 486                                 fsid_type = FSID_UUID4_INUM;
 487                 }
 488         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 489                 /* for newer device numbers, we must use a newer fsid format */
 490                 fsid_type = FSID_ENCODE_DEV;
 491         else
 492                 fsid_type = FSID_DEV;
 493         fhp->fh_handle.fh_version = version;
 494         if (version)
 495                 fhp->fh_handle.fh_fsid_type = fsid_type;
 496 }
 497
 498 __be32
 499 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 500            struct svc_fh *ref_fh)
 501 {
 502         /* ref_fh is a reference file handle.
 503          * if it is non-null and for the same filesystem, then we should compose
 504          * a filehandle which is of the same version, where possible.
 505          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 506          * Then create a 32byte filehandle using nfs_fhbase_old
 507          *
 508          */
 509
 510         struct inode * inode = dentry->d_inode;
 511         struct dentry *parent = dentry->d_parent;
 512         __u32 *datap;
 513         dev_t ex_dev = exp_sb(exp)->s_dev;
 514
 515         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 516                 MAJOR(ex_dev), MINOR(ex_dev),
 517                 (long) exp->ex_path.dentry->d_inode->i_ino,
 518                 parent->d_name.name, dentry->d_name.name,
 519                 (inode ? inode->i_ino : 0));
 520
 521         /* Choose filehandle version and fsid type based on
 522          * the reference filehandle (if it is in the same export)
 523          * or the export options.
 524          */
 525          set_version_and_fsid_type(fhp, exp, ref_fh);
 526
 527         if (ref_fh == fhp)
 528                 fh_put(ref_fh);
 529
 530         if (fhp->fh_locked || fhp->fh_dentry) {
 531                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 532                        parent->d_name.name, dentry->d_name.name);
 533         }
 534         if (fhp->fh_maxsize < NFS_FHSIZE)
 535                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 536                        fhp->fh_maxsize,
 537                        parent->d_name.name, dentry->d_name.name);
 538
 539         fhp->fh_dentry = dget(dentry); /* our internal copy */
 540         fhp->fh_export = exp;
 541         cache_get(&exp->h);
 542
 543         if (fhp->fh_handle.fh_version == 0xca) {
 544                 /* old style filehandle please */
 545                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 546                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 547                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 548                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 549                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 550                 fhp->fh_handle.ofh_xino =
 551                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 552                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 553                 if (inode)
 554                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 555         } else {
 556                 int len;
 557                 fhp->fh_handle.fh_auth_type = 0;
 558                 datap = fhp->fh_handle.fh_auth+0;
 559                 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
 560                         exp->ex_path.dentry->d_inode->i_ino,
 561                         exp->ex_fsid, exp->ex_uuid);
 562
 563                 len = key_len(fhp->fh_handle.fh_fsid_type);
 564                 datap += len/4;
 565                 fhp->fh_handle.fh_size = 4 + len;
 566
 567                 if (inode)
 568                         _fh_update(fhp, exp, dentry);
 569                 if (fhp->fh_handle.fh_fileid_type == 255) {
 570                         fh_put(fhp);
 571                         return nfserr_opnotsupp;
 572                 }
 573         }
 574
 575         return 0;
 576 }
 577
 578 /*
 579  * Update file handle information after changing a dentry.
 580  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 581  */
 582 __be32
 583 fh_update(struct svc_fh *fhp)
 584 {
 585         struct dentry *dentry;
 586
 587         if (!fhp->fh_dentry)
 588                 goto out_bad;
 589
 590         dentry = fhp->fh_dentry;
 591         if (!dentry->d_inode)
 592                 goto out_negative;
 593         if (fhp->fh_handle.fh_version != 1) {
 594                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 595         } else {
 596                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 597                         goto out;
 598
 599                 _fh_update(fhp, fhp->fh_export, dentry);
 600                 if (fhp->fh_handle.fh_fileid_type == 255)
 601                         return nfserr_opnotsupp;
 602         }
 603 out:
 604         return 0;
 605
 606 out_bad:
 607         printk(KERN_ERR "fh_update: fh not verified!\n");
 608         goto out;
 609 out_negative:
 610         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 611                 dentry->d_parent->d_name.name, dentry->d_name.name);
 612         goto out;
 613 }
 614
 615 /*
 616  * Release a file handle.
 617  */
 618 void
 619 fh_put(struct svc_fh *fhp)
 620 {
 621         struct dentry * dentry = fhp->fh_dentry;
 622         struct svc_export * exp = fhp->fh_export;
 623         if (dentry) {
 624                 fh_unlock(fhp);
 625                 fhp->fh_dentry = NULL;
 626                 dput(dentry);
 627 #ifdef CONFIG_NFSD_V3
 628                 fhp->fh_pre_saved = 0;
 629                 fhp->fh_post_saved = 0;
 630 #endif
 631         }
 632         if (exp) {
 633                 cache_put(&exp->h, &svc_export_cache);
 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 }