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