1 /*
2 * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
3 *
4 * This software may be freely redistributed under the terms of the
5 * GNU General Public License.
6 *
7 * You should have received a copy of the GNU General Public License
8 * along with this program; if not, write to the Free Software
9 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
10 *
11 * Authors: David Woodhouse <dwmw2@infradead.org>
12 * David Howells <dhowells@redhat.com>
13 *
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/sched.h>
22 #include <linux/mount.h>
23 #include <linux/namei.h>
24 #include <linux/iversion.h>
25 #include "internal.h"
26
27 static const struct inode_operations afs_symlink_inode_operations = {
28 .get_link = page_get_link,
29 .listxattr = afs_listxattr,
30 };
31
32 /*
33 * Initialise an inode from the vnode status.
34 */
afs_inode_init_from_status(struct afs_vnode * vnode,struct key * key)35 static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key)
36 {
37 struct inode *inode = AFS_VNODE_TO_I(vnode);
38
39 _debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
40 vnode->status.type,
41 vnode->status.nlink,
42 (unsigned long long) vnode->status.size,
43 vnode->status.data_version,
44 vnode->status.mode);
45
46 read_seqlock_excl(&vnode->cb_lock);
47
48 afs_update_inode_from_status(vnode, &vnode->status, NULL,
49 AFS_VNODE_NOT_YET_SET);
50
51 switch (vnode->status.type) {
52 case AFS_FTYPE_FILE:
53 inode->i_mode = S_IFREG | vnode->status.mode;
54 inode->i_op = &afs_file_inode_operations;
55 inode->i_fop = &afs_file_operations;
56 inode->i_mapping->a_ops = &afs_fs_aops;
57 break;
58 case AFS_FTYPE_DIR:
59 inode->i_mode = S_IFDIR | vnode->status.mode;
60 inode->i_op = &afs_dir_inode_operations;
61 inode->i_fop = &afs_dir_file_operations;
62 inode->i_mapping->a_ops = &afs_dir_aops;
63 break;
64 case AFS_FTYPE_SYMLINK:
65 /* Symlinks with a mode of 0644 are actually mountpoints. */
66 if ((vnode->status.mode & 0777) == 0644) {
67 inode->i_flags |= S_AUTOMOUNT;
68
69 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
70
71 inode->i_mode = S_IFDIR | 0555;
72 inode->i_op = &afs_mntpt_inode_operations;
73 inode->i_fop = &afs_mntpt_file_operations;
74 inode->i_mapping->a_ops = &afs_fs_aops;
75 } else {
76 inode->i_mode = S_IFLNK | vnode->status.mode;
77 inode->i_op = &afs_symlink_inode_operations;
78 inode->i_mapping->a_ops = &afs_fs_aops;
79 }
80 inode_nohighmem(inode);
81 break;
82 default:
83 printk("kAFS: AFS vnode with undefined type\n");
84 read_sequnlock_excl(&vnode->cb_lock);
85 return afs_protocol_error(NULL, -EBADMSG);
86 }
87
88 inode->i_blocks = 0;
89 vnode->invalid_before = vnode->status.data_version;
90
91 read_sequnlock_excl(&vnode->cb_lock);
92 return 0;
93 }
94
95 /*
96 * Fetch file status from the volume.
97 */
afs_fetch_status(struct afs_vnode * vnode,struct key * key,bool new_inode)98 int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool new_inode)
99 {
100 struct afs_fs_cursor fc;
101 int ret;
102
103 _enter("%s,{%x:%u.%u,S=%lx}",
104 vnode->volume->name,
105 vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
106 vnode->flags);
107
108 ret = -ERESTARTSYS;
109 if (afs_begin_vnode_operation(&fc, vnode, key)) {
110 while (afs_select_fileserver(&fc)) {
111 fc.cb_break = afs_calc_vnode_cb_break(vnode);
112 afs_fs_fetch_file_status(&fc, NULL, new_inode);
113 }
114
115 afs_check_for_remote_deletion(&fc, fc.vnode);
116 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
117 ret = afs_end_vnode_operation(&fc);
118 }
119
120 _leave(" = %d", ret);
121 return ret;
122 }
123
124 /*
125 * iget5() comparator
126 */
afs_iget5_test(struct inode * inode,void * opaque)127 int afs_iget5_test(struct inode *inode, void *opaque)
128 {
129 struct afs_iget_data *data = opaque;
130
131 return inode->i_ino == data->fid.vnode &&
132 inode->i_generation == data->fid.unique;
133 }
134
135 /*
136 * iget5() comparator for inode created by autocell operations
137 *
138 * These pseudo inodes don't match anything.
139 */
afs_iget5_pseudo_dir_test(struct inode * inode,void * opaque)140 static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
141 {
142 return 0;
143 }
144
145 /*
146 * iget5() inode initialiser
147 */
afs_iget5_set(struct inode * inode,void * opaque)148 static int afs_iget5_set(struct inode *inode, void *opaque)
149 {
150 struct afs_iget_data *data = opaque;
151 struct afs_vnode *vnode = AFS_FS_I(inode);
152
153 inode->i_ino = data->fid.vnode;
154 inode->i_generation = data->fid.unique;
155 vnode->fid = data->fid;
156 vnode->volume = data->volume;
157
158 return 0;
159 }
160
161 /*
162 * Create an inode for a dynamic root directory or an autocell dynamic
163 * automount dir.
164 */
afs_iget_pseudo_dir(struct super_block * sb,bool root)165 struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
166 {
167 struct afs_iget_data data;
168 struct afs_super_info *as;
169 struct afs_vnode *vnode;
170 struct inode *inode;
171 static atomic_t afs_autocell_ino;
172
173 _enter("");
174
175 as = sb->s_fs_info;
176 if (as->volume) {
177 data.volume = as->volume;
178 data.fid.vid = as->volume->vid;
179 }
180 if (root) {
181 data.fid.vnode = 1;
182 data.fid.unique = 1;
183 } else {
184 data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
185 data.fid.unique = 0;
186 }
187
188 inode = iget5_locked(sb, data.fid.vnode,
189 afs_iget5_pseudo_dir_test, afs_iget5_set,
190 &data);
191 if (!inode) {
192 _leave(" = -ENOMEM");
193 return ERR_PTR(-ENOMEM);
194 }
195
196 _debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
197 inode, inode->i_ino, data.fid.vid, data.fid.vnode,
198 data.fid.unique);
199
200 vnode = AFS_FS_I(inode);
201
202 /* there shouldn't be an existing inode */
203 BUG_ON(!(inode->i_state & I_NEW));
204
205 inode->i_size = 0;
206 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
207 if (root) {
208 inode->i_op = &afs_dynroot_inode_operations;
209 inode->i_fop = &afs_dynroot_file_operations;
210 } else {
211 inode->i_op = &afs_autocell_inode_operations;
212 }
213 set_nlink(inode, 2);
214 inode->i_uid = GLOBAL_ROOT_UID;
215 inode->i_gid = GLOBAL_ROOT_GID;
216 inode->i_ctime.tv_sec = get_seconds();
217 inode->i_ctime.tv_nsec = 0;
218 inode->i_atime = inode->i_mtime = inode->i_ctime;
219 inode->i_blocks = 0;
220 inode_set_iversion_raw(inode, 0);
221 inode->i_generation = 0;
222
223 set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
224 if (!root) {
225 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
226 inode->i_flags |= S_AUTOMOUNT;
227 }
228
229 inode->i_flags |= S_NOATIME;
230 unlock_new_inode(inode);
231 _leave(" = %p", inode);
232 return inode;
233 }
234
235 /*
236 * Get a cache cookie for an inode.
237 */
afs_get_inode_cache(struct afs_vnode * vnode)238 static void afs_get_inode_cache(struct afs_vnode *vnode)
239 {
240 #ifdef CONFIG_AFS_FSCACHE
241 struct {
242 u32 vnode_id;
243 u32 unique;
244 u32 vnode_id_ext[2]; /* Allow for a 96-bit key */
245 } __packed key;
246 struct afs_vnode_cache_aux aux;
247
248 if (vnode->status.type == AFS_FTYPE_DIR) {
249 vnode->cache = NULL;
250 return;
251 }
252
253 key.vnode_id = vnode->fid.vnode;
254 key.unique = vnode->fid.unique;
255 key.vnode_id_ext[0] = 0;
256 key.vnode_id_ext[1] = 0;
257 aux.data_version = vnode->status.data_version;
258
259 vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
260 &afs_vnode_cache_index_def,
261 &key, sizeof(key),
262 &aux, sizeof(aux),
263 vnode, vnode->status.size, true);
264 #endif
265 }
266
267 /*
268 * inode retrieval
269 */
afs_iget(struct super_block * sb,struct key * key,struct afs_fid * fid,struct afs_file_status * status,struct afs_callback * cb,struct afs_cb_interest * cbi)270 struct inode *afs_iget(struct super_block *sb, struct key *key,
271 struct afs_fid *fid, struct afs_file_status *status,
272 struct afs_callback *cb, struct afs_cb_interest *cbi)
273 {
274 struct afs_iget_data data = { .fid = *fid };
275 struct afs_super_info *as;
276 struct afs_vnode *vnode;
277 struct inode *inode;
278 int ret;
279
280 _enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
281
282 as = sb->s_fs_info;
283 data.volume = as->volume;
284
285 inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
286 &data);
287 if (!inode) {
288 _leave(" = -ENOMEM");
289 return ERR_PTR(-ENOMEM);
290 }
291
292 _debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
293 inode, fid->vid, fid->vnode, fid->unique);
294
295 vnode = AFS_FS_I(inode);
296
297 /* deal with an existing inode */
298 if (!(inode->i_state & I_NEW)) {
299 _leave(" = %p", inode);
300 return inode;
301 }
302
303 if (!status) {
304 /* it's a remotely extant inode */
305 ret = afs_fetch_status(vnode, key, true);
306 if (ret < 0)
307 goto bad_inode;
308 } else {
309 /* it's an inode we just created */
310 memcpy(&vnode->status, status, sizeof(vnode->status));
311
312 if (!cb) {
313 /* it's a symlink we just created (the fileserver
314 * didn't give us a callback) */
315 vnode->cb_version = 0;
316 vnode->cb_type = 0;
317 vnode->cb_expires_at = 0;
318 } else {
319 vnode->cb_version = cb->version;
320 vnode->cb_type = cb->type;
321 vnode->cb_expires_at = cb->expiry;
322 vnode->cb_interest = afs_get_cb_interest(cbi);
323 set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
324 }
325
326 vnode->cb_expires_at += ktime_get_real_seconds();
327 }
328
329 ret = afs_inode_init_from_status(vnode, key);
330 if (ret < 0)
331 goto bad_inode;
332
333 afs_get_inode_cache(vnode);
334
335 /* success */
336 clear_bit(AFS_VNODE_UNSET, &vnode->flags);
337 inode->i_flags |= S_NOATIME;
338 unlock_new_inode(inode);
339 _leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
340 return inode;
341
342 /* failure */
343 bad_inode:
344 iget_failed(inode);
345 _leave(" = %d [bad]", ret);
346 return ERR_PTR(ret);
347 }
348
349 /*
350 * mark the data attached to an inode as obsolete due to a write on the server
351 * - might also want to ditch all the outstanding writes and dirty pages
352 */
afs_zap_data(struct afs_vnode * vnode)353 void afs_zap_data(struct afs_vnode *vnode)
354 {
355 _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
356
357 #ifdef CONFIG_AFS_FSCACHE
358 fscache_invalidate(vnode->cache);
359 #endif
360
361 /* nuke all the non-dirty pages that aren't locked, mapped or being
362 * written back in a regular file and completely discard the pages in a
363 * directory or symlink */
364 if (S_ISREG(vnode->vfs_inode.i_mode))
365 invalidate_remote_inode(&vnode->vfs_inode);
366 else
367 invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
368 }
369
370 /*
371 * validate a vnode/inode
372 * - there are several things we need to check
373 * - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
374 * symlink)
375 * - parent dir metadata changed (security changes)
376 * - dentry data changed (write, truncate)
377 * - dentry metadata changed (security changes)
378 */
afs_validate(struct afs_vnode * vnode,struct key * key)379 int afs_validate(struct afs_vnode *vnode, struct key *key)
380 {
381 time64_t now = ktime_get_real_seconds();
382 bool valid;
383 int ret;
384
385 _enter("{v={%x:%u} fl=%lx},%x",
386 vnode->fid.vid, vnode->fid.vnode, vnode->flags,
387 key_serial(key));
388
389 /* Quickly check the callback state. Ideally, we'd use read_seqbegin
390 * here, but we have no way to pass the net namespace to the RCU
391 * cleanup for the server record.
392 */
393 read_seqlock_excl(&vnode->cb_lock);
394
395 if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
396 if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break ||
397 vnode->cb_v_break != vnode->volume->cb_v_break) {
398 vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
399 vnode->cb_v_break = vnode->volume->cb_v_break;
400 valid = false;
401 } else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
402 valid = false;
403 } else if (vnode->cb_expires_at - 10 <= now) {
404 valid = false;
405 } else {
406 valid = true;
407 }
408 } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
409 valid = true;
410 } else {
411 vnode->cb_v_break = vnode->volume->cb_v_break;
412 valid = false;
413 }
414
415 read_sequnlock_excl(&vnode->cb_lock);
416
417 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
418 clear_nlink(&vnode->vfs_inode);
419
420 if (valid)
421 goto valid;
422
423 down_write(&vnode->validate_lock);
424
425 /* if the promise has expired, we need to check the server again to get
426 * a new promise - note that if the (parent) directory's metadata was
427 * changed then the security may be different and we may no longer have
428 * access */
429 if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
430 _debug("not promised");
431 ret = afs_fetch_status(vnode, key, false);
432 if (ret < 0) {
433 if (ret == -ENOENT) {
434 set_bit(AFS_VNODE_DELETED, &vnode->flags);
435 ret = -ESTALE;
436 }
437 goto error_unlock;
438 }
439 _debug("new promise [fl=%lx]", vnode->flags);
440 }
441
442 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
443 _debug("file already deleted");
444 ret = -ESTALE;
445 goto error_unlock;
446 }
447
448 /* if the vnode's data version number changed then its contents are
449 * different */
450 if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
451 afs_zap_data(vnode);
452 up_write(&vnode->validate_lock);
453 valid:
454 _leave(" = 0");
455 return 0;
456
457 error_unlock:
458 up_write(&vnode->validate_lock);
459 _leave(" = %d", ret);
460 return ret;
461 }
462
463 /*
464 * read the attributes of an inode
465 */
afs_getattr(const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)466 int afs_getattr(const struct path *path, struct kstat *stat,
467 u32 request_mask, unsigned int query_flags)
468 {
469 struct inode *inode = d_inode(path->dentry);
470 struct afs_vnode *vnode = AFS_FS_I(inode);
471 struct key *key;
472 int ret, seq = 0;
473
474 _enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
475
476 if (vnode->volume &&
477 !(query_flags & AT_STATX_DONT_SYNC) &&
478 !test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
479 key = afs_request_key(vnode->volume->cell);
480 if (IS_ERR(key))
481 return PTR_ERR(key);
482 ret = afs_validate(vnode, key);
483 key_put(key);
484 if (ret < 0)
485 return ret;
486 }
487
488 do {
489 read_seqbegin_or_lock(&vnode->cb_lock, &seq);
490 generic_fillattr(inode, stat);
491 } while (need_seqretry(&vnode->cb_lock, seq));
492
493 done_seqretry(&vnode->cb_lock, seq);
494 return 0;
495 }
496
497 /*
498 * discard an AFS inode
499 */
afs_drop_inode(struct inode * inode)500 int afs_drop_inode(struct inode *inode)
501 {
502 _enter("");
503
504 if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
505 return generic_delete_inode(inode);
506 else
507 return generic_drop_inode(inode);
508 }
509
510 /*
511 * clear an AFS inode
512 */
afs_evict_inode(struct inode * inode)513 void afs_evict_inode(struct inode *inode)
514 {
515 struct afs_vnode *vnode;
516
517 vnode = AFS_FS_I(inode);
518
519 _enter("{%x:%u.%d}",
520 vnode->fid.vid,
521 vnode->fid.vnode,
522 vnode->fid.unique);
523
524 _debug("CLEAR INODE %p", inode);
525
526 ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
527
528 truncate_inode_pages_final(&inode->i_data);
529 clear_inode(inode);
530
531 if (vnode->cb_interest) {
532 afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
533 vnode->cb_interest = NULL;
534 }
535
536 while (!list_empty(&vnode->wb_keys)) {
537 struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
538 struct afs_wb_key, vnode_link);
539 list_del(&wbk->vnode_link);
540 afs_put_wb_key(wbk);
541 }
542
543 #ifdef CONFIG_AFS_FSCACHE
544 {
545 struct afs_vnode_cache_aux aux;
546
547 aux.data_version = vnode->status.data_version;
548 fscache_relinquish_cookie(vnode->cache, &aux,
549 test_bit(AFS_VNODE_DELETED, &vnode->flags));
550 vnode->cache = NULL;
551 }
552 #endif
553
554 afs_prune_wb_keys(vnode);
555 afs_put_permits(rcu_access_pointer(vnode->permit_cache));
556 key_put(vnode->lock_key);
557 vnode->lock_key = NULL;
558 _leave("");
559 }
560
561 /*
562 * set the attributes of an inode
563 */
afs_setattr(struct dentry * dentry,struct iattr * attr)564 int afs_setattr(struct dentry *dentry, struct iattr *attr)
565 {
566 struct afs_fs_cursor fc;
567 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
568 struct key *key;
569 int ret;
570
571 _enter("{%x:%u},{n=%pd},%x",
572 vnode->fid.vid, vnode->fid.vnode, dentry,
573 attr->ia_valid);
574
575 if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
576 ATTR_MTIME))) {
577 _leave(" = 0 [unsupported]");
578 return 0;
579 }
580
581 /* flush any dirty data outstanding on a regular file */
582 if (S_ISREG(vnode->vfs_inode.i_mode))
583 filemap_write_and_wait(vnode->vfs_inode.i_mapping);
584
585 if (attr->ia_valid & ATTR_FILE) {
586 key = afs_file_key(attr->ia_file);
587 } else {
588 key = afs_request_key(vnode->volume->cell);
589 if (IS_ERR(key)) {
590 ret = PTR_ERR(key);
591 goto error;
592 }
593 }
594
595 ret = -ERESTARTSYS;
596 if (afs_begin_vnode_operation(&fc, vnode, key)) {
597 while (afs_select_fileserver(&fc)) {
598 fc.cb_break = afs_calc_vnode_cb_break(vnode);
599 afs_fs_setattr(&fc, attr);
600 }
601
602 afs_check_for_remote_deletion(&fc, fc.vnode);
603 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
604 ret = afs_end_vnode_operation(&fc);
605 }
606
607 if (!(attr->ia_valid & ATTR_FILE))
608 key_put(key);
609
610 error:
611 _leave(" = %d", ret);
612 return ret;
613 }
614