fs/nfsd/nfsfh.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * NFS server file handle treatment.
   4  *
   5  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   6  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
   7  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
   8  * ... and again Southern-Winter 2001 to support export_operations
   9  */
  10
  11 #include <linux/exportfs.h>
  12
  13 #include <linux/sunrpc/svcauth_gss.h>
  14 #include "nfsd.h"
  15 #include "vfs.h"
  16 #include "auth.h"
  17 #include "trace.h"
  18
  19 #define NFSDDBG_FACILITY                NFSDDBG_FH
  20
  21
  22 /*
  23  * our acceptability function.
  24  * if NOSUBTREECHECK, accept anything
  25  * if not, require that we can walk up to exp->ex_dentry
  26  * doing some checks on the 'x' bits
  27  */
  28 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  29 {
  30         struct svc_export *exp = expv;
  31         int rv;
  32         struct dentry *tdentry;
  33         struct dentry *parent;
  34
  35         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  36                 return 1;
  37
  38         tdentry = dget(dentry);
  39         while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
  40                 /* make sure parents give x permission to user */
  41                 int err;
  42                 parent = dget_parent(tdentry);
  43                 err = inode_permission(d_inode(parent), MAY_EXEC);
  44                 if (err < 0) {
  45                         dput(parent);
  46                         break;
  47                 }
  48                 dput(tdentry);
  49                 tdentry = parent;
  50         }
  51         if (tdentry != exp->ex_path.dentry)
  52                 dprintk("nfsd_acceptable failed at %p %pd\n", tdentry, tdentry);
  53         rv = (tdentry == exp->ex_path.dentry);
  54         dput(tdentry);
  55         return rv;
  56 }
  57
  58 /* Type check. The correct error return for type mismatches does not seem to be
  59  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  60  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  61  * the write call).
  62  */
  63 static inline __be32
  64 nfsd_mode_check(struct svc_rqst *rqstp, struct dentry *dentry,
  65                 umode_t requested)
  66 {
  67         umode_t mode = d_inode(dentry)->i_mode & S_IFMT;
  68
  69         if (requested == 0) /* the caller doesn't care */
  70                 return nfs_ok;
  71         if (mode == requested) {
  72                 if (mode == S_IFDIR && !d_can_lookup(dentry)) {
  73                         WARN_ON_ONCE(1);
  74                         return nfserr_notdir;
  75                 }
  76                 return nfs_ok;
  77         }
  78         /*
  79          * v4 has an error more specific than err_notdir which we should
  80          * return in preference to err_notdir:
  81          */
  82         if (rqstp->rq_vers == 4 && mode == S_IFLNK)
  83                 return nfserr_symlink;
  84         if (requested == S_IFDIR)
  85                 return nfserr_notdir;
  86         if (mode == S_IFDIR)
  87                 return nfserr_isdir;
  88         return nfserr_inval;
  89 }
  90
  91 static bool nfsd_originating_port_ok(struct svc_rqst *rqstp, int flags)
  92 {
  93         if (flags & NFSEXP_INSECURE_PORT)
  94                 return true;
  95         /* We don't require gss requests to use low ports: */
  96         if (rqstp->rq_cred.cr_flavor >= RPC_AUTH_GSS)
  97                 return true;
  98         return test_bit(RQ_SECURE, &rqstp->rq_flags);
  99 }
 100
 101 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 102                                           struct svc_export *exp)
 103 {
 104         int flags = nfsexp_flags(rqstp, exp);
 105
 106         /* Check if the request originated from a secure port. */
 107         if (!nfsd_originating_port_ok(rqstp, flags)) {
 108                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 109                 dprintk("nfsd: request from insecure port %s!\n",
 110                         svc_print_addr(rqstp, buf, sizeof(buf)));
 111                 return nfserr_perm;
 112         }
 113
 114         /* Set user creds for this exportpoint */
 115         return nfserrno(nfsd_setuser(rqstp, exp));
 116 }
 117
 118 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
 119         struct dentry *dentry, struct svc_export *exp)
 120 {
 121         if (!(exp->ex_flags & NFSEXP_V4ROOT))
 122                 return nfs_ok;
 123         /*
 124          * v2/v3 clients have no need for the V4ROOT export--they use
 125          * the mount protocl instead; also, further V4ROOT checks may be
 126          * in v4-specific code, in which case v2/v3 clients could bypass
 127          * them.
 128          */
 129         if (!nfsd_v4client(rqstp))
 130                 return nfserr_stale;
 131         /*
 132          * We're exposing only the directories and symlinks that have to be
 133          * traversed on the way to real exports:
 134          */
 135         if (unlikely(!d_is_dir(dentry) &&
 136                      !d_is_symlink(dentry)))
 137                 return nfserr_stale;
 138         /*
 139          * A pseudoroot export gives permission to access only one
 140          * single directory; the kernel has to make another upcall
 141          * before granting access to anything else under it:
 142          */
 143         if (unlikely(dentry != exp->ex_path.dentry))
 144                 return nfserr_stale;
 145         return nfs_ok;
 146 }
 147
 148 /*
 149  * Use the given filehandle to look up the corresponding export and
 150  * dentry.  On success, the results are used to set fh_export and
 151  * fh_dentry.
 152  */
 153 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 154 {
 155         struct knfsd_fh *fh = &fhp->fh_handle;
 156         struct fid *fid = NULL, sfid;
 157         struct svc_export *exp;
 158         struct dentry *dentry;
 159         int fileid_type;
 160         int data_left = fh->fh_size/4;
 161         __be32 error;
 162
 163         error = nfserr_stale;
 164         if (rqstp->rq_vers > 2)
 165                 error = nfserr_badhandle;
 166         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 167                 return nfserr_nofilehandle;
 168
 169         if (fh->fh_version == 1) {
 170                 int len;
 171
 172                 if (--data_left < 0)
 173                         return error;
 174                 if (fh->fh_auth_type != 0)
 175                         return error;
 176                 len = key_len(fh->fh_fsid_type) / 4;
 177                 if (len == 0)
 178                         return error;
 179                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 180                         /* deprecated, convert to type 3 */
 181                         len = key_len(FSID_ENCODE_DEV)/4;
 182                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 183                         /*
 184                          * struct knfsd_fh uses host-endian fields, which are
 185                          * sometimes used to hold net-endian values. This
 186                          * confuses sparse, so we must use __force here to
 187                          * keep it from complaining.
 188                          */
 189                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
 190                                                         ntohl((__force __be32)fh->fh_fsid[1])));
 191                         fh->fh_fsid[1] = fh->fh_fsid[2];
 192                 }
 193                 data_left -= len;
 194                 if (data_left < 0)
 195                         return error;
 196                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_fsid);
 197                 fid = (struct fid *)(fh->fh_fsid + len);
 198         } else {
 199                 __u32 tfh[2];
 200                 dev_t xdev;
 201                 ino_t xino;
 202
 203                 if (fh->fh_size != NFS_FHSIZE)
 204                         return error;
 205                 /* assume old filehandle format */
 206                 xdev = old_decode_dev(fh->ofh_xdev);
 207                 xino = u32_to_ino_t(fh->ofh_xino);
 208                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 209                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 210         }
 211
 212         error = nfserr_stale;
 213         if (IS_ERR(exp)) {
 214                 trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
 215
 216                 if (PTR_ERR(exp) == -ENOENT)
 217                         return error;
 218
 219                 return nfserrno(PTR_ERR(exp));
 220         }
 221
 222         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
 223                 /* Elevate privileges so that the lack of 'r' or 'x'
 224                  * permission on some parent directory will
 225                  * not stop exportfs_decode_fh from being able
 226                  * to reconnect a directory into the dentry cache.
 227                  * The same problem can affect "SUBTREECHECK" exports,
 228                  * but as nfsd_acceptable depends on correct
 229                  * access control settings being in effect, we cannot
 230                  * fix that case easily.
 231                  */
 232                 struct cred *new = prepare_creds();
 233                 if (!new) {
 234                         error =  nfserrno(-ENOMEM);
 235                         goto out;
 236                 }
 237                 new->cap_effective =
 238                         cap_raise_nfsd_set(new->cap_effective,
 239                                            new->cap_permitted);
 240                 put_cred(override_creds(new));
 241                 put_cred(new);
 242         } else {
 243                 error = nfsd_setuser_and_check_port(rqstp, exp);
 244                 if (error)
 245                         goto out;
 246         }
 247
 248         /*
 249          * Look up the dentry using the NFS file handle.
 250          */
 251         error = nfserr_stale;
 252         if (rqstp->rq_vers > 2)
 253                 error = nfserr_badhandle;
 254
 255         if (fh->fh_version != 1) {
 256                 sfid.i32.ino = fh->ofh_ino;
 257                 sfid.i32.gen = fh->ofh_generation;
 258                 sfid.i32.parent_ino = fh->ofh_dirino;
 259                 fid = &sfid;
 260                 data_left = 3;
 261                 if (fh->ofh_dirino == 0)
 262                         fileid_type = FILEID_INO32_GEN;
 263                 else
 264                         fileid_type = FILEID_INO32_GEN_PARENT;
 265         } else
 266                 fileid_type = fh->fh_fileid_type;
 267
 268         if (fileid_type == FILEID_ROOT)
 269                 dentry = dget(exp->ex_path.dentry);
 270         else {
 271                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 272                                 data_left, fileid_type,
 273                                 nfsd_acceptable, exp);
 274                 if (IS_ERR_OR_NULL(dentry))
 275                         trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
 276                                         dentry ?  PTR_ERR(dentry) : -ESTALE);
 277         }
 278         if (dentry == NULL)
 279                 goto out;
 280         if (IS_ERR(dentry)) {
 281                 if (PTR_ERR(dentry) != -EINVAL)
 282                         error = nfserrno(PTR_ERR(dentry));
 283                 goto out;
 284         }
 285
 286         if (d_is_dir(dentry) &&
 287                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 288                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
 289                                 dentry);
 290         }
 291
 292         fhp->fh_dentry = dentry;
 293         fhp->fh_export = exp;
 294         return 0;
 295 out:
 296         exp_put(exp);
 297         return error;
 298 }
 299
 300 /**
 301  * fh_verify - filehandle lookup and access checking
 302  * @rqstp: pointer to current rpc request
 303  * @fhp: filehandle to be verified
 304  * @type: expected type of object pointed to by filehandle
 305  * @access: type of access needed to object
 306  *
 307  * Look up a dentry from the on-the-wire filehandle, check the client's
 308  * access to the export, and set the current task's credentials.
 309  *
 310  * Regardless of success or failure of fh_verify(), fh_put() should be
 311  * called on @fhp when the caller is finished with the filehandle.
 312  *
 313  * fh_verify() may be called multiple times on a given filehandle, for
 314  * example, when processing an NFSv4 compound.  The first call will look
 315  * up a dentry using the on-the-wire filehandle.  Subsequent calls will
 316  * skip the lookup and just perform the other checks and possibly change
 317  * the current task's credentials.
 318  *
 319  * @type specifies the type of object expected using one of the S_IF*
 320  * constants defined in include/linux/stat.h.  The caller may use zero
 321  * to indicate that it doesn't care, or a negative integer to indicate
 322  * that it expects something not of the given type.
 323  *
 324  * @access is formed from the NFSD_MAY_* constants defined in
 325  * fs/nfsd/vfs.h.
 326  */
 327 __be32
 328 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
 329 {
 330         struct svc_export *exp;
 331         struct dentry   *dentry;
 332         __be32          error;
 333
 334         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 335
 336         if (!fhp->fh_dentry) {
 337                 error = nfsd_set_fh_dentry(rqstp, fhp);
 338                 if (error)
 339                         goto out;
 340         }
 341         dentry = fhp->fh_dentry;
 342         exp = fhp->fh_export;
 343         /*
 344          * We still have to do all these permission checks, even when
 345          * fh_dentry is already set:
 346          *      - fh_verify may be called multiple times with different
 347          *        "access" arguments (e.g. nfsd_proc_create calls
 348          *        fh_verify(...,NFSD_MAY_EXEC) first, then later (in
 349          *        nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
 350          *      - in the NFSv4 case, the filehandle may have been filled
 351          *        in by fh_compose, and given a dentry, but further
 352          *        compound operations performed with that filehandle
 353          *        still need permissions checks.  In the worst case, a
 354          *        mountpoint crossing may have changed the export
 355          *        options, and we may now need to use a different uid
 356          *        (for example, if different id-squashing options are in
 357          *        effect on the new filesystem).
 358          */
 359         error = check_pseudo_root(rqstp, dentry, exp);
 360         if (error)
 361                 goto out;
 362
 363         error = nfsd_setuser_and_check_port(rqstp, exp);
 364         if (error)
 365                 goto out;
 366
 367         error = nfsd_mode_check(rqstp, dentry, type);
 368         if (error)
 369                 goto out;
 370
 371         /*
 372          * pseudoflavor restrictions are not enforced on NLM,
 373          * which clients virtually always use auth_sys for,
 374          * even while using RPCSEC_GSS for NFS.
 375          */
 376         if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
 377                 goto skip_pseudoflavor_check;
 378         /*
 379          * Clients may expect to be able to use auth_sys during mount,
 380          * even if they use gss for everything else; see section 2.3.2
 381          * of rfc 2623.
 382          */
 383         if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
 384                         && exp->ex_path.dentry == dentry)
 385                 goto skip_pseudoflavor_check;
 386
 387         error = check_nfsd_access(exp, rqstp);
 388         if (error)
 389                 goto out;
 390
 391 skip_pseudoflavor_check:
 392         /* Finally, check access permissions. */
 393         error = nfsd_permission(rqstp, exp, dentry, access);
 394
 395         if (error) {
 396                 dprintk("fh_verify: %pd2 permission failure, "
 397                         "acc=%x, error=%d\n",
 398                         dentry,
 399                         access, ntohl(error));
 400         }
 401 out:
 402         if (error == nfserr_stale)
 403                 nfsdstats.fh_stale++;
 404         return error;
 405 }
 406
 407
 408 /*
 409  * Compose a file handle for an NFS reply.
 410  *
 411  * Note that when first composed, the dentry may not yet have
 412  * an inode.  In this case a call to fh_update should be made
 413  * before the fh goes out on the wire ...
 414  */
 415 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 416                 struct dentry *dentry)
 417 {
 418         if (dentry != exp->ex_path.dentry) {
 419                 struct fid *fid = (struct fid *)
 420                         (fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
 421                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 422                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 423
 424                 fhp->fh_handle.fh_fileid_type =
 425                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 426                 fhp->fh_handle.fh_size += maxsize * 4;
 427         } else {
 428                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 429         }
 430 }
 431
 432 /*
 433  * for composing old style file handles
 434  */
 435 static inline void _fh_update_old(struct dentry *dentry,
 436                                   struct svc_export *exp,
 437                                   struct knfsd_fh *fh)
 438 {
 439         fh->ofh_ino = ino_t_to_u32(d_inode(dentry)->i_ino);
 440         fh->ofh_generation = d_inode(dentry)->i_generation;
 441         if (d_is_dir(dentry) ||
 442             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 443                 fh->ofh_dirino = 0;
 444 }
 445
 446 static bool is_root_export(struct svc_export *exp)
 447 {
 448         return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
 449 }
 450
 451 static struct super_block *exp_sb(struct svc_export *exp)
 452 {
 453         return exp->ex_path.dentry->d_sb;
 454 }
 455
 456 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
 457 {
 458         switch (fsid_type) {
 459         case FSID_DEV:
 460                 if (!old_valid_dev(exp_sb(exp)->s_dev))
 461                         return false;
 462                 fallthrough;
 463         case FSID_MAJOR_MINOR:
 464         case FSID_ENCODE_DEV:
 465                 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
 466         case FSID_NUM:
 467                 return exp->ex_flags & NFSEXP_FSID;
 468         case FSID_UUID8:
 469         case FSID_UUID16:
 470                 if (!is_root_export(exp))
 471                         return false;
 472                 fallthrough;
 473         case FSID_UUID4_INUM:
 474         case FSID_UUID16_INUM:
 475                 return exp->ex_uuid != NULL;
 476         }
 477         return true;
 478 }
 479
 480
 481 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
 482 {
 483         u8 version;
 484         u8 fsid_type;
 485 retry:
 486         version = 1;
 487         if (ref_fh && ref_fh->fh_export == exp) {
 488                 version = ref_fh->fh_handle.fh_version;
 489                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 490
 491                 ref_fh = NULL;
 492
 493                 switch (version) {
 494                 case 0xca:
 495                         fsid_type = FSID_DEV;
 496                         break;
 497                 case 1:
 498                         break;
 499                 default:
 500                         goto retry;
 501                 }
 502
 503                 /*
 504                  * As the fsid -> filesystem mapping was guided by
 505                  * user-space, there is no guarantee that the filesystem
 506                  * actually supports that fsid type. If it doesn't we
 507                  * loop around again without ref_fh set.
 508                  */
 509                 if (!fsid_type_ok_for_exp(fsid_type, exp))
 510                         goto retry;
 511         } else if (exp->ex_flags & NFSEXP_FSID) {
 512                 fsid_type = FSID_NUM;
 513         } else if (exp->ex_uuid) {
 514                 if (fhp->fh_maxsize >= 64) {
 515                         if (is_root_export(exp))
 516                                 fsid_type = FSID_UUID16;
 517                         else
 518                                 fsid_type = FSID_UUID16_INUM;
 519                 } else {
 520                         if (is_root_export(exp))
 521                                 fsid_type = FSID_UUID8;
 522                         else
 523                                 fsid_type = FSID_UUID4_INUM;
 524                 }
 525         } else if (!old_valid_dev(exp_sb(exp)->s_dev))
 526                 /* for newer device numbers, we must use a newer fsid format */
 527                 fsid_type = FSID_ENCODE_DEV;
 528         else
 529                 fsid_type = FSID_DEV;
 530         fhp->fh_handle.fh_version = version;
 531         if (version)
 532                 fhp->fh_handle.fh_fsid_type = fsid_type;
 533 }
 534
 535 __be32
 536 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 537            struct svc_fh *ref_fh)
 538 {
 539         /* ref_fh is a reference file handle.
 540          * if it is non-null and for the same filesystem, then we should compose
 541          * a filehandle which is of the same version, where possible.
 542          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 543          * Then create a 32byte filehandle using nfs_fhbase_old
 544          *
 545          */
 546
 547         struct inode * inode = d_inode(dentry);
 548         dev_t ex_dev = exp_sb(exp)->s_dev;
 549
 550         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
 551                 MAJOR(ex_dev), MINOR(ex_dev),
 552                 (long) d_inode(exp->ex_path.dentry)->i_ino,
 553                 dentry,
 554                 (inode ? inode->i_ino : 0));
 555
 556         /* Choose filehandle version and fsid type based on
 557          * the reference filehandle (if it is in the same export)
 558          * or the export options.
 559          */
 560         set_version_and_fsid_type(fhp, exp, ref_fh);
 561
 562         if (ref_fh == fhp)
 563                 fh_put(ref_fh);
 564
 565         if (fhp->fh_locked || fhp->fh_dentry) {
 566                 printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
 567                        dentry);
 568         }
 569         if (fhp->fh_maxsize < NFS_FHSIZE)
 570                 printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
 571                        fhp->fh_maxsize,
 572                        dentry);
 573
 574         fhp->fh_dentry = dget(dentry); /* our internal copy */
 575         fhp->fh_export = exp_get(exp);
 576
 577         if (fhp->fh_handle.fh_version == 0xca) {
 578                 /* old style filehandle please */
 579                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 580                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 581                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 582                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 583                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 584                 fhp->fh_handle.ofh_xino =
 585                         ino_t_to_u32(d_inode(exp->ex_path.dentry)->i_ino);
 586                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 587                 if (inode)
 588                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 589         } else {
 590                 fhp->fh_handle.fh_size =
 591                         key_len(fhp->fh_handle.fh_fsid_type) + 4;
 592                 fhp->fh_handle.fh_auth_type = 0;
 593
 594                 mk_fsid(fhp->fh_handle.fh_fsid_type,
 595                         fhp->fh_handle.fh_fsid,
 596                         ex_dev,
 597                         d_inode(exp->ex_path.dentry)->i_ino,
 598                         exp->ex_fsid, exp->ex_uuid);
 599
 600                 if (inode)
 601                         _fh_update(fhp, exp, dentry);
 602                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
 603                         fh_put(fhp);
 604                         return nfserr_opnotsupp;
 605                 }
 606         }
 607
 608         return 0;
 609 }
 610
 611 /*
 612  * Update file handle information after changing a dentry.
 613  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 614  */
 615 __be32
 616 fh_update(struct svc_fh *fhp)
 617 {
 618         struct dentry *dentry;
 619
 620         if (!fhp->fh_dentry)
 621                 goto out_bad;
 622
 623         dentry = fhp->fh_dentry;
 624         if (d_really_is_negative(dentry))
 625                 goto out_negative;
 626         if (fhp->fh_handle.fh_version != 1) {
 627                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 628         } else {
 629                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 630                         return 0;
 631
 632                 _fh_update(fhp, fhp->fh_export, dentry);
 633                 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
 634                         return nfserr_opnotsupp;
 635         }
 636         return 0;
 637 out_bad:
 638         printk(KERN_ERR "fh_update: fh not verified!\n");
 639         return nfserr_serverfault;
 640 out_negative:
 641         printk(KERN_ERR "fh_update: %pd2 still negative!\n",
 642                 dentry);
 643         return nfserr_serverfault;
 644 }
 645
 646 /*
 647  * Release a file handle.
 648  */
 649 void
 650 fh_put(struct svc_fh *fhp)
 651 {
 652         struct dentry * dentry = fhp->fh_dentry;
 653         struct svc_export * exp = fhp->fh_export;
 654         if (dentry) {
 655                 fh_unlock(fhp);
 656                 fhp->fh_dentry = NULL;
 657                 dput(dentry);
 658                 fh_clear_wcc(fhp);
 659         }
 660         fh_drop_write(fhp);
 661         if (exp) {
 662                 exp_put(exp);
 663                 fhp->fh_export = NULL;
 664         }
 665         return;
 666 }
 667
 668 /*
 669  * Shorthand for dprintk()'s
 670  */
 671 char * SVCFH_fmt(struct svc_fh *fhp)
 672 {
 673         struct knfsd_fh *fh = &fhp->fh_handle;
 674
 675         static char buf[80];
 676         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 677                 fh->fh_size,
 678                 fh->fh_base.fh_pad[0],
 679                 fh->fh_base.fh_pad[1],
 680                 fh->fh_base.fh_pad[2],
 681                 fh->fh_base.fh_pad[3],
 682                 fh->fh_base.fh_pad[4],
 683                 fh->fh_base.fh_pad[5]);
 684         return buf;
 685 }
 686
 687 enum fsid_source fsid_source(struct svc_fh *fhp)
 688 {
 689         if (fhp->fh_handle.fh_version != 1)
 690                 return FSIDSOURCE_DEV;
 691         switch(fhp->fh_handle.fh_fsid_type) {
 692         case FSID_DEV:
 693         case FSID_ENCODE_DEV:
 694         case FSID_MAJOR_MINOR:
 695                 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
 696                         return FSIDSOURCE_DEV;
 697                 break;
 698         case FSID_NUM:
 699                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 700                         return FSIDSOURCE_FSID;
 701                 break;
 702         default:
 703                 break;
 704         }
 705         /* either a UUID type filehandle, or the filehandle doesn't
 706          * match the export.
 707          */
 708         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 709                 return FSIDSOURCE_FSID;
 710         if (fhp->fh_export->ex_uuid)
 711                 return FSIDSOURCE_UUID;
 712         return FSIDSOURCE_DEV;
 713 }