Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6] / fs / nfsd / nfsfh.c
1 /*
2  * linux/fs/nfsd/nfsfh.c
3  *
4  * NFS server file handle treatment.
5  *
6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
8  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
9  * ... and again Southern-Winter 2001 to support export_operations
10  */
11
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14 #include <linux/unistd.h>
15 #include <linux/string.h>
16 #include <linux/stat.h>
17 #include <linux/dcache.h>
18 #include <linux/mount.h>
19
20 #include <linux/sunrpc/clnt.h>
21 #include <linux/sunrpc/svc.h>
22 #include <linux/nfsd/nfsd.h>
23
24 #define NFSDDBG_FACILITY                NFSDDBG_FH
25
26
27 static int nfsd_nr_verified;
28 static int nfsd_nr_put;
29
30 extern struct export_operations export_op_default;
31
32 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
33
34 /*
35  * our acceptability function.
36  * if NOSUBTREECHECK, accept anything
37  * if not, require that we can walk up to exp->ex_dentry
38  * doing some checks on the 'x' bits
39  */
40 static int nfsd_acceptable(void *expv, struct dentry *dentry)
41 {
42         struct svc_export *exp = expv;
43         int rv;
44         struct dentry *tdentry;
45         struct dentry *parent;
46
47         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
48                 return 1;
49
50         tdentry = dget(dentry);
51         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
52                 /* make sure parents give x permission to user */
53                 int err;
54                 parent = dget_parent(tdentry);
55                 err = permission(parent->d_inode, MAY_EXEC, NULL);
56                 if (err < 0) {
57                         dput(parent);
58                         break;
59                 }
60                 dput(tdentry);
61                 tdentry = parent;
62         }
63         if (tdentry != exp->ex_dentry)
64                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
65         rv = (tdentry == exp->ex_dentry);
66         dput(tdentry);
67         return rv;
68 }
69
70 /* Type check. The correct error return for type mismatches does not seem to be
71  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
72  * comment in the NFSv3 spec says this is incorrect (implementation notes for
73  * the write call).
74  */
75 static inline __be32
76 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
77 {
78         /* Type can be negative when creating hardlinks - not to a dir */
79         if (type > 0 && (mode & S_IFMT) != type) {
80                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
81                         return nfserr_symlink;
82                 else if (type == S_IFDIR)
83                         return nfserr_notdir;
84                 else if ((mode & S_IFMT) == S_IFDIR)
85                         return nfserr_isdir;
86                 else
87                         return nfserr_inval;
88         }
89         if (type < 0 && (mode & S_IFMT) == -type) {
90                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
91                         return nfserr_symlink;
92                 else if (type == -S_IFDIR)
93                         return nfserr_isdir;
94                 else
95                         return nfserr_notdir;
96         }
97         return 0;
98 }
99
100 /*
101  * Perform sanity checks on the dentry in a client's file handle.
102  *
103  * Note that the file handle dentry may need to be freed even after
104  * an error return.
105  *
106  * This is only called at the start of an nfsproc call, so fhp points to
107  * a svc_fh which is all 0 except for the over-the-wire file handle.
108  */
109 __be32
110 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
111 {
112         struct knfsd_fh *fh = &fhp->fh_handle;
113         struct svc_export *exp = NULL;
114         struct dentry   *dentry;
115         __be32          error = 0;
116
117         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
118
119         if (!fhp->fh_dentry) {
120                 __u32 *datap=NULL;
121                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
122                 int fileid_type;
123                 int data_left = fh->fh_size/4;
124
125                 error = nfserr_stale;
126                 if (rqstp->rq_client == NULL)
127                         goto out;
128                 if (rqstp->rq_vers > 2)
129                         error = nfserr_badhandle;
130                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
131                         return nfserr_nofilehandle;
132
133                 if (fh->fh_version == 1) {
134                         int len;
135                         datap = fh->fh_auth;
136                         if (--data_left<0) goto out;
137                         switch (fh->fh_auth_type) {
138                         case 0: break;
139                         default: goto out;
140                         }
141                         len = key_len(fh->fh_fsid_type) / 4;
142                         if (len == 0) goto out;
143                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
144                                 /* deprecated, convert to type 3 */
145                                 len = key_len(FSID_ENCODE_DEV)/4;
146                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
147                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
148                                 fh->fh_fsid[1] = fh->fh_fsid[2];
149                         }
150                         if ((data_left -= len)<0) goto out;
151                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
152                         datap += len;
153                 } else {
154                         dev_t xdev;
155                         ino_t xino;
156                         if (fh->fh_size != NFS_FHSIZE)
157                                 goto out;
158                         /* assume old filehandle format */
159                         xdev = old_decode_dev(fh->ofh_xdev);
160                         xino = u32_to_ino_t(fh->ofh_xino);
161                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
162                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
163                                        &rqstp->rq_chandle);
164                 }
165
166                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
167                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
168                         error = nfserrno(PTR_ERR(exp));
169                         goto out;
170                 }
171
172                 error = nfserr_stale; 
173                 if (!exp || IS_ERR(exp))
174                         goto out;
175
176                 /* Check if the request originated from a secure port. */
177                 error = nfserr_perm;
178                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
179                         char buf[RPC_MAX_ADDRBUFLEN];
180                         printk(KERN_WARNING
181                                "nfsd: request from insecure port %s!\n",
182                                svc_print_addr(rqstp, buf, sizeof(buf)));
183                         goto out;
184                 }
185
186                 /* Set user creds for this exportpoint */
187                 error = nfserrno(nfsd_setuser(rqstp, exp));
188                 if (error)
189                         goto out;
190
191                 /*
192                  * Look up the dentry using the NFS file handle.
193                  */
194                 error = nfserr_stale;
195                 if (rqstp->rq_vers > 2)
196                         error = nfserr_badhandle;
197
198                 if (fh->fh_version != 1) {
199                         tfh[0] = fh->ofh_ino;
200                         tfh[1] = fh->ofh_generation;
201                         tfh[2] = fh->ofh_dirino;
202                         datap = tfh;
203                         data_left = 3;
204                         if (fh->ofh_dirino == 0)
205                                 fileid_type = 1;
206                         else
207                                 fileid_type = 2;
208                 } else
209                         fileid_type = fh->fh_fileid_type;
210
211                 if (fileid_type == 0)
212                         dentry = dget(exp->ex_dentry);
213                 else {
214                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
215                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
216                                                      datap, data_left,
217                                                      fileid_type,
218                                                      nfsd_acceptable, exp);
219                 }
220                 if (dentry == NULL)
221                         goto out;
222                 if (IS_ERR(dentry)) {
223                         if (PTR_ERR(dentry) != -EINVAL)
224                                 error = nfserrno(PTR_ERR(dentry));
225                         goto out;
226                 }
227
228                 if (S_ISDIR(dentry->d_inode->i_mode) &&
229                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
230                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
231                                dentry->d_parent->d_name.name, dentry->d_name.name);
232                 }
233
234                 fhp->fh_dentry = dentry;
235                 fhp->fh_export = exp;
236                 nfsd_nr_verified++;
237         } else {
238                 /* just rechecking permissions
239                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
240                  */
241                 dprintk("nfsd: fh_verify - just checking\n");
242                 dentry = fhp->fh_dentry;
243                 exp = fhp->fh_export;
244                 /* Set user creds for this exportpoint; necessary even
245                  * in the "just checking" case because this may be a
246                  * filehandle that was created by fh_compose, and that
247                  * is about to be used in another nfsv4 compound
248                  * operation */
249                 error = nfserrno(nfsd_setuser(rqstp, exp));
250                 if (error)
251                         goto out;
252         }
253         cache_get(&exp->h);
254
255
256         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
257         if (error)
258                 goto out;
259
260         /* Finally, check access permissions. */
261         error = nfsd_permission(exp, dentry, access);
262
263         if (error) {
264                 dprintk("fh_verify: %s/%s permission failure, "
265                         "acc=%x, error=%d\n",
266                         dentry->d_parent->d_name.name,
267                         dentry->d_name.name,
268                         access, ntohl(error));
269         }
270 out:
271         if (exp && !IS_ERR(exp))
272                 exp_put(exp);
273         if (error == nfserr_stale)
274                 nfsdstats.fh_stale++;
275         return error;
276 }
277
278
279 /*
280  * Compose a file handle for an NFS reply.
281  *
282  * Note that when first composed, the dentry may not yet have
283  * an inode.  In this case a call to fh_update should be made
284  * before the fh goes out on the wire ...
285  */
286 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
287                              __u32 *datap, int *maxsize)
288 {
289         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
290
291         if (dentry == exp->ex_dentry) {
292                 *maxsize = 0;
293                 return 0;
294         }
295
296         return CALL(nop,encode_fh)(dentry, datap, maxsize,
297                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
298 }
299
300 /*
301  * for composing old style file handles
302  */
303 static inline void _fh_update_old(struct dentry *dentry,
304                                   struct svc_export *exp,
305                                   struct knfsd_fh *fh)
306 {
307         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
308         fh->ofh_generation = dentry->d_inode->i_generation;
309         if (S_ISDIR(dentry->d_inode->i_mode) ||
310             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
311                 fh->ofh_dirino = 0;
312 }
313
314 __be32
315 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
316            struct svc_fh *ref_fh)
317 {
318         /* ref_fh is a reference file handle.
319          * if it is non-null and for the same filesystem, then we should compose
320          * a filehandle which is of the same version, where possible.
321          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
322          * Then create a 32byte filehandle using nfs_fhbase_old
323          *
324          */
325
326         u8 version;
327         u8 fsid_type = 0;
328         struct inode * inode = dentry->d_inode;
329         struct dentry *parent = dentry->d_parent;
330         __u32 *datap;
331         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
332         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
333
334         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
335                 MAJOR(ex_dev), MINOR(ex_dev),
336                 (long) exp->ex_dentry->d_inode->i_ino,
337                 parent->d_name.name, dentry->d_name.name,
338                 (inode ? inode->i_ino : 0));
339
340         /* Choose filehandle version and fsid type based on
341          * the reference filehandle (if it is in the same export)
342          * or the export options.
343          */
344  retry:
345         version = 1;
346         if (ref_fh && ref_fh->fh_export == exp) {
347                 version = ref_fh->fh_handle.fh_version;
348                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
349
350                 if (ref_fh == fhp)
351                         fh_put(ref_fh);
352                 ref_fh = NULL;
353
354                 switch (version) {
355                 case 0xca:
356                         fsid_type = FSID_DEV;
357                         break;
358                 case 1:
359                         break;
360                 default:
361                         goto retry;
362                 }
363
364                 /* Need to check that this type works for this
365                  * export point.  As the fsid -> filesystem mapping
366                  * was guided by user-space, there is no guarantee
367                  * that the filesystem actually supports that fsid
368                  * type. If it doesn't we loop around again without
369                  * ref_fh set.
370                  */
371                 switch(fsid_type) {
372                 case FSID_DEV:
373                         if (!old_valid_dev(ex_dev))
374                                 goto retry;
375                         /* FALL THROUGH */
376                 case FSID_MAJOR_MINOR:
377                 case FSID_ENCODE_DEV:
378                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
379                               & FS_REQUIRES_DEV))
380                                 goto retry;
381                         break;
382                 case FSID_NUM:
383                         if (! (exp->ex_flags & NFSEXP_FSID))
384                                 goto retry;
385                         break;
386                 case FSID_UUID8:
387                 case FSID_UUID16:
388                         if (!root_export)
389                                 goto retry;
390                         /* fall through */
391                 case FSID_UUID4_INUM:
392                 case FSID_UUID16_INUM:
393                         if (exp->ex_uuid == NULL)
394                                 goto retry;
395                         break;
396                 }
397         } else if (exp->ex_uuid) {
398                 if (fhp->fh_maxsize >= 64) {
399                         if (root_export)
400                                 fsid_type = FSID_UUID16;
401                         else
402                                 fsid_type = FSID_UUID16_INUM;
403                 } else {
404                         if (root_export)
405                                 fsid_type = FSID_UUID8;
406                         else
407                                 fsid_type = FSID_UUID4_INUM;
408                 }
409         } else if (exp->ex_flags & NFSEXP_FSID)
410                 fsid_type = FSID_NUM;
411         else if (!old_valid_dev(ex_dev))
412                 /* for newer device numbers, we must use a newer fsid format */
413                 fsid_type = FSID_ENCODE_DEV;
414         else
415                 fsid_type = FSID_DEV;
416
417         if (ref_fh == fhp)
418                 fh_put(ref_fh);
419
420         if (fhp->fh_locked || fhp->fh_dentry) {
421                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
422                        parent->d_name.name, dentry->d_name.name);
423         }
424         if (fhp->fh_maxsize < NFS_FHSIZE)
425                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
426                        fhp->fh_maxsize,
427                        parent->d_name.name, dentry->d_name.name);
428
429         fhp->fh_dentry = dget(dentry); /* our internal copy */
430         fhp->fh_export = exp;
431         cache_get(&exp->h);
432
433         if (version == 0xca) {
434                 /* old style filehandle please */
435                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
436                 fhp->fh_handle.fh_size = NFS_FHSIZE;
437                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
438                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
439                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
440                 fhp->fh_handle.ofh_xino =
441                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
442                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
443                 if (inode)
444                         _fh_update_old(dentry, exp, &fhp->fh_handle);
445         } else {
446                 int len;
447                 fhp->fh_handle.fh_version = 1;
448                 fhp->fh_handle.fh_auth_type = 0;
449                 datap = fhp->fh_handle.fh_auth+0;
450                 fhp->fh_handle.fh_fsid_type = fsid_type;
451                 mk_fsid(fsid_type, datap, ex_dev,
452                         exp->ex_dentry->d_inode->i_ino,
453                         exp->ex_fsid, exp->ex_uuid);
454
455                 len = key_len(fsid_type);
456                 datap += len/4;
457                 fhp->fh_handle.fh_size = 4 + len;
458
459                 if (inode) {
460                         int size = (fhp->fh_maxsize-len-4)/4;
461                         fhp->fh_handle.fh_fileid_type =
462                                 _fh_update(dentry, exp, datap, &size);
463                         fhp->fh_handle.fh_size += size*4;
464                 }
465                 if (fhp->fh_handle.fh_fileid_type == 255)
466                         return nfserr_opnotsupp;
467         }
468
469         nfsd_nr_verified++;
470         return 0;
471 }
472
473 /*
474  * Update file handle information after changing a dentry.
475  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
476  */
477 __be32
478 fh_update(struct svc_fh *fhp)
479 {
480         struct dentry *dentry;
481         __u32 *datap;
482
483         if (!fhp->fh_dentry)
484                 goto out_bad;
485
486         dentry = fhp->fh_dentry;
487         if (!dentry->d_inode)
488                 goto out_negative;
489         if (fhp->fh_handle.fh_version != 1) {
490                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
491         } else {
492                 int size;
493                 if (fhp->fh_handle.fh_fileid_type != 0)
494                         goto out;
495                 datap = fhp->fh_handle.fh_auth+
496                         fhp->fh_handle.fh_size/4 -1;
497                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
498                 fhp->fh_handle.fh_fileid_type =
499                         _fh_update(dentry, fhp->fh_export, datap, &size);
500                 fhp->fh_handle.fh_size += size*4;
501                 if (fhp->fh_handle.fh_fileid_type == 255)
502                         return nfserr_opnotsupp;
503         }
504 out:
505         return 0;
506
507 out_bad:
508         printk(KERN_ERR "fh_update: fh not verified!\n");
509         goto out;
510 out_negative:
511         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
512                 dentry->d_parent->d_name.name, dentry->d_name.name);
513         goto out;
514 }
515
516 /*
517  * Release a file handle.
518  */
519 void
520 fh_put(struct svc_fh *fhp)
521 {
522         struct dentry * dentry = fhp->fh_dentry;
523         struct svc_export * exp = fhp->fh_export;
524         if (dentry) {
525                 fh_unlock(fhp);
526                 fhp->fh_dentry = NULL;
527                 dput(dentry);
528 #ifdef CONFIG_NFSD_V3
529                 fhp->fh_pre_saved = 0;
530                 fhp->fh_post_saved = 0;
531 #endif
532                 nfsd_nr_put++;
533         }
534         if (exp) {
535                 cache_put(&exp->h, &svc_export_cache);
536                 fhp->fh_export = NULL;
537         }
538         return;
539 }
540
541 /*
542  * Shorthand for dprintk()'s
543  */
544 char * SVCFH_fmt(struct svc_fh *fhp)
545 {
546         struct knfsd_fh *fh = &fhp->fh_handle;
547
548         static char buf[80];
549         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
550                 fh->fh_size,
551                 fh->fh_base.fh_pad[0],
552                 fh->fh_base.fh_pad[1],
553                 fh->fh_base.fh_pad[2],
554                 fh->fh_base.fh_pad[3],
555                 fh->fh_base.fh_pad[4],
556                 fh->fh_base.fh_pad[5]);
557         return buf;
558 }
559
560 enum fsid_source fsid_source(struct svc_fh *fhp)
561 {
562         if (fhp->fh_handle.fh_version != 1)
563                 return FSIDSOURCE_DEV;
564         switch(fhp->fh_handle.fh_fsid_type) {
565         case FSID_DEV:
566         case FSID_ENCODE_DEV:
567         case FSID_MAJOR_MINOR:
568                 return FSIDSOURCE_DEV;
569         case FSID_NUM:
570                 return FSIDSOURCE_FSID;
571         default:
572                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
573                         return FSIDSOURCE_FSID;
574                 else
575                         return FSIDSOURCE_UUID;
576         }
577 }