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1 | /* CacheFiles path walking and related routines | |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/file.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/fsnotify.h> | |
17 | #include <linux/quotaops.h> | |
18 | #include <linux/xattr.h> | |
19 | #include <linux/mount.h> | |
20 | #include <linux/namei.h> | |
21 | #include <linux/security.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/xattr.h> | |
24 | #include "internal.h" | |
25 | ||
26 | #define CACHEFILES_KEYBUF_SIZE 512 | |
27 | ||
28 | /* | |
29 | * dump debugging info about an object | |
30 | */ | |
31 | static noinline | |
32 | void __cachefiles_printk_object(struct cachefiles_object *object, | |
33 | const char *prefix, | |
34 | u8 *keybuf) | |
35 | { | |
36 | struct fscache_cookie *cookie; | |
37 | unsigned keylen, loop; | |
38 | ||
39 | pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id); | |
40 | pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", | |
41 | prefix, object->fscache.state->name, | |
42 | object->fscache.flags, work_busy(&object->fscache.work), | |
43 | object->fscache.events, object->fscache.event_mask); | |
44 | pr_err("%sops=%u inp=%u exc=%u\n", | |
45 | prefix, object->fscache.n_ops, object->fscache.n_in_progress, | |
46 | object->fscache.n_exclusive); | |
47 | pr_err("%sparent=%p\n", | |
48 | prefix, object->fscache.parent); | |
49 | ||
50 | spin_lock(&object->fscache.lock); | |
51 | cookie = object->fscache.cookie; | |
52 | if (cookie) { | |
53 | pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n", | |
54 | prefix, | |
55 | object->fscache.cookie, | |
56 | object->fscache.cookie->parent, | |
57 | object->fscache.cookie->netfs_data, | |
58 | object->fscache.cookie->flags); | |
59 | if (keybuf && cookie->def) | |
60 | keylen = cookie->def->get_key(cookie->netfs_data, keybuf, | |
61 | CACHEFILES_KEYBUF_SIZE); | |
62 | else | |
63 | keylen = 0; | |
64 | } else { | |
65 | pr_err("%scookie=NULL\n", prefix); | |
66 | keylen = 0; | |
67 | } | |
68 | spin_unlock(&object->fscache.lock); | |
69 | ||
70 | if (keylen) { | |
71 | pr_err("%skey=[%u] '", prefix, keylen); | |
72 | for (loop = 0; loop < keylen; loop++) | |
73 | pr_cont("%02x", keybuf[loop]); | |
74 | pr_cont("'\n"); | |
75 | } | |
76 | } | |
77 | ||
78 | /* | |
79 | * dump debugging info about a pair of objects | |
80 | */ | |
81 | static noinline void cachefiles_printk_object(struct cachefiles_object *object, | |
82 | struct cachefiles_object *xobject) | |
83 | { | |
84 | u8 *keybuf; | |
85 | ||
86 | keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); | |
87 | if (object) | |
88 | __cachefiles_printk_object(object, "", keybuf); | |
89 | if (xobject) | |
90 | __cachefiles_printk_object(xobject, "x", keybuf); | |
91 | kfree(keybuf); | |
92 | } | |
93 | ||
94 | /* | |
95 | * mark the owner of a dentry, if there is one, to indicate that that dentry | |
96 | * has been preemptively deleted | |
97 | * - the caller must hold the i_mutex on the dentry's parent as required to | |
98 | * call vfs_unlink(), vfs_rmdir() or vfs_rename() | |
99 | */ | |
100 | static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, | |
101 | struct dentry *dentry, | |
102 | enum fscache_why_object_killed why) | |
103 | { | |
104 | struct cachefiles_object *object; | |
105 | struct rb_node *p; | |
106 | ||
107 | _enter(",'%pd'", dentry); | |
108 | ||
109 | write_lock(&cache->active_lock); | |
110 | ||
111 | p = cache->active_nodes.rb_node; | |
112 | while (p) { | |
113 | object = rb_entry(p, struct cachefiles_object, active_node); | |
114 | if (object->dentry > dentry) | |
115 | p = p->rb_left; | |
116 | else if (object->dentry < dentry) | |
117 | p = p->rb_right; | |
118 | else | |
119 | goto found_dentry; | |
120 | } | |
121 | ||
122 | write_unlock(&cache->active_lock); | |
123 | _leave(" [no owner]"); | |
124 | return; | |
125 | ||
126 | /* found the dentry for */ | |
127 | found_dentry: | |
128 | kdebug("preemptive burial: OBJ%x [%s] %p", | |
129 | object->fscache.debug_id, | |
130 | object->fscache.state->name, | |
131 | dentry); | |
132 | ||
133 | if (fscache_object_is_live(&object->fscache)) { | |
134 | pr_err("\n"); | |
135 | pr_err("Error: Can't preemptively bury live object\n"); | |
136 | cachefiles_printk_object(object, NULL); | |
137 | } else { | |
138 | if (why != FSCACHE_OBJECT_IS_STALE) | |
139 | fscache_object_mark_killed(&object->fscache, why); | |
140 | } | |
141 | ||
142 | write_unlock(&cache->active_lock); | |
143 | _leave(" [owner marked]"); | |
144 | } | |
145 | ||
146 | /* | |
147 | * record the fact that an object is now active | |
148 | */ | |
149 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, | |
150 | struct cachefiles_object *object) | |
151 | { | |
152 | struct cachefiles_object *xobject; | |
153 | struct rb_node **_p, *_parent = NULL; | |
154 | struct dentry *dentry; | |
155 | ||
156 | _enter(",%p", object); | |
157 | ||
158 | try_again: | |
159 | write_lock(&cache->active_lock); | |
160 | ||
161 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { | |
162 | pr_err("Error: Object already active\n"); | |
163 | cachefiles_printk_object(object, NULL); | |
164 | BUG(); | |
165 | } | |
166 | ||
167 | dentry = object->dentry; | |
168 | _p = &cache->active_nodes.rb_node; | |
169 | while (*_p) { | |
170 | _parent = *_p; | |
171 | xobject = rb_entry(_parent, | |
172 | struct cachefiles_object, active_node); | |
173 | ||
174 | ASSERT(xobject != object); | |
175 | ||
176 | if (xobject->dentry > dentry) | |
177 | _p = &(*_p)->rb_left; | |
178 | else if (xobject->dentry < dentry) | |
179 | _p = &(*_p)->rb_right; | |
180 | else | |
181 | goto wait_for_old_object; | |
182 | } | |
183 | ||
184 | rb_link_node(&object->active_node, _parent, _p); | |
185 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
186 | ||
187 | write_unlock(&cache->active_lock); | |
188 | _leave(" = 0"); | |
189 | return 0; | |
190 | ||
191 | /* an old object from a previous incarnation is hogging the slot - we | |
192 | * need to wait for it to be destroyed */ | |
193 | wait_for_old_object: | |
194 | if (fscache_object_is_live(&xobject->fscache)) { | |
195 | pr_err("\n"); | |
196 | pr_err("Error: Unexpected object collision\n"); | |
197 | cachefiles_printk_object(object, xobject); | |
198 | BUG(); | |
199 | } | |
200 | atomic_inc(&xobject->usage); | |
201 | write_unlock(&cache->active_lock); | |
202 | ||
203 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
204 | wait_queue_head_t *wq; | |
205 | ||
206 | signed long timeout = 60 * HZ; | |
207 | wait_queue_t wait; | |
208 | bool requeue; | |
209 | ||
210 | /* if the object we're waiting for is queued for processing, | |
211 | * then just put ourselves on the queue behind it */ | |
212 | if (work_pending(&xobject->fscache.work)) { | |
213 | _debug("queue OBJ%x behind OBJ%x immediately", | |
214 | object->fscache.debug_id, | |
215 | xobject->fscache.debug_id); | |
216 | goto requeue; | |
217 | } | |
218 | ||
219 | /* otherwise we sleep until either the object we're waiting for | |
220 | * is done, or the fscache_object is congested */ | |
221 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); | |
222 | init_wait(&wait); | |
223 | requeue = false; | |
224 | do { | |
225 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
226 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
227 | break; | |
228 | ||
229 | requeue = fscache_object_sleep_till_congested(&timeout); | |
230 | } while (timeout > 0 && !requeue); | |
231 | finish_wait(wq, &wait); | |
232 | ||
233 | if (requeue && | |
234 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
235 | _debug("queue OBJ%x behind OBJ%x after wait", | |
236 | object->fscache.debug_id, | |
237 | xobject->fscache.debug_id); | |
238 | goto requeue; | |
239 | } | |
240 | ||
241 | if (timeout <= 0) { | |
242 | pr_err("\n"); | |
243 | pr_err("Error: Overlong wait for old active object to go away\n"); | |
244 | cachefiles_printk_object(object, xobject); | |
245 | goto requeue; | |
246 | } | |
247 | } | |
248 | ||
249 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
250 | ||
251 | cache->cache.ops->put_object(&xobject->fscache); | |
252 | goto try_again; | |
253 | ||
254 | requeue: | |
255 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
256 | cache->cache.ops->put_object(&xobject->fscache); | |
257 | _leave(" = -ETIMEDOUT"); | |
258 | return -ETIMEDOUT; | |
259 | } | |
260 | ||
261 | /* | |
262 | * Mark an object as being inactive. | |
263 | */ | |
264 | void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, | |
265 | struct cachefiles_object *object, | |
266 | blkcnt_t i_blocks) | |
267 | { | |
268 | write_lock(&cache->active_lock); | |
269 | rb_erase(&object->active_node, &cache->active_nodes); | |
270 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
271 | write_unlock(&cache->active_lock); | |
272 | ||
273 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
274 | ||
275 | /* This object can now be culled, so we need to let the daemon know | |
276 | * that there is something it can remove if it needs to. | |
277 | */ | |
278 | atomic_long_add(i_blocks, &cache->b_released); | |
279 | if (atomic_inc_return(&cache->f_released)) | |
280 | cachefiles_state_changed(cache); | |
281 | } | |
282 | ||
283 | /* | |
284 | * delete an object representation from the cache | |
285 | * - file backed objects are unlinked | |
286 | * - directory backed objects are stuffed into the graveyard for userspace to | |
287 | * delete | |
288 | * - unlocks the directory mutex | |
289 | */ | |
290 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
291 | struct dentry *dir, | |
292 | struct dentry *rep, | |
293 | bool preemptive, | |
294 | enum fscache_why_object_killed why) | |
295 | { | |
296 | struct dentry *grave, *trap; | |
297 | struct path path, path_to_graveyard; | |
298 | char nbuffer[8 + 8 + 1]; | |
299 | int ret; | |
300 | ||
301 | _enter(",'%pd','%pd'", dir, rep); | |
302 | ||
303 | _debug("remove %p from %p", rep, dir); | |
304 | ||
305 | /* non-directories can just be unlinked */ | |
306 | if (!d_is_dir(rep)) { | |
307 | _debug("unlink stale object"); | |
308 | ||
309 | path.mnt = cache->mnt; | |
310 | path.dentry = dir; | |
311 | ret = security_path_unlink(&path, rep); | |
312 | if (ret < 0) { | |
313 | cachefiles_io_error(cache, "Unlink security error"); | |
314 | } else { | |
315 | ret = vfs_unlink(d_inode(dir), rep, NULL); | |
316 | ||
317 | if (preemptive) | |
318 | cachefiles_mark_object_buried(cache, rep, why); | |
319 | } | |
320 | ||
321 | inode_unlock(d_inode(dir)); | |
322 | ||
323 | if (ret == -EIO) | |
324 | cachefiles_io_error(cache, "Unlink failed"); | |
325 | ||
326 | _leave(" = %d", ret); | |
327 | return ret; | |
328 | } | |
329 | ||
330 | /* directories have to be moved to the graveyard */ | |
331 | _debug("move stale object to graveyard"); | |
332 | inode_unlock(d_inode(dir)); | |
333 | ||
334 | try_again: | |
335 | /* first step is to make up a grave dentry in the graveyard */ | |
336 | sprintf(nbuffer, "%08x%08x", | |
337 | (uint32_t) get_seconds(), | |
338 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
339 | ||
340 | /* do the multiway lock magic */ | |
341 | trap = lock_rename(cache->graveyard, dir); | |
342 | ||
343 | /* do some checks before getting the grave dentry */ | |
344 | if (rep->d_parent != dir) { | |
345 | /* the entry was probably culled when we dropped the parent dir | |
346 | * lock */ | |
347 | unlock_rename(cache->graveyard, dir); | |
348 | _leave(" = 0 [culled?]"); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | if (!d_can_lookup(cache->graveyard)) { | |
353 | unlock_rename(cache->graveyard, dir); | |
354 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
355 | return -EIO; | |
356 | } | |
357 | ||
358 | if (trap == rep) { | |
359 | unlock_rename(cache->graveyard, dir); | |
360 | cachefiles_io_error(cache, "May not make directory loop"); | |
361 | return -EIO; | |
362 | } | |
363 | ||
364 | if (d_mountpoint(rep)) { | |
365 | unlock_rename(cache->graveyard, dir); | |
366 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
367 | return -EIO; | |
368 | } | |
369 | ||
370 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
371 | if (IS_ERR(grave)) { | |
372 | unlock_rename(cache->graveyard, dir); | |
373 | ||
374 | if (PTR_ERR(grave) == -ENOMEM) { | |
375 | _leave(" = -ENOMEM"); | |
376 | return -ENOMEM; | |
377 | } | |
378 | ||
379 | cachefiles_io_error(cache, "Lookup error %ld", | |
380 | PTR_ERR(grave)); | |
381 | return -EIO; | |
382 | } | |
383 | ||
384 | if (d_is_positive(grave)) { | |
385 | unlock_rename(cache->graveyard, dir); | |
386 | dput(grave); | |
387 | grave = NULL; | |
388 | cond_resched(); | |
389 | goto try_again; | |
390 | } | |
391 | ||
392 | if (d_mountpoint(grave)) { | |
393 | unlock_rename(cache->graveyard, dir); | |
394 | dput(grave); | |
395 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
396 | return -EIO; | |
397 | } | |
398 | ||
399 | /* target should not be an ancestor of source */ | |
400 | if (trap == grave) { | |
401 | unlock_rename(cache->graveyard, dir); | |
402 | dput(grave); | |
403 | cachefiles_io_error(cache, "May not make directory loop"); | |
404 | return -EIO; | |
405 | } | |
406 | ||
407 | /* attempt the rename */ | |
408 | path.mnt = cache->mnt; | |
409 | path.dentry = dir; | |
410 | path_to_graveyard.mnt = cache->mnt; | |
411 | path_to_graveyard.dentry = cache->graveyard; | |
412 | ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); | |
413 | if (ret < 0) { | |
414 | cachefiles_io_error(cache, "Rename security error %d", ret); | |
415 | } else { | |
416 | ret = vfs_rename(d_inode(dir), rep, | |
417 | d_inode(cache->graveyard), grave, NULL, 0); | |
418 | if (ret != 0 && ret != -ENOMEM) | |
419 | cachefiles_io_error(cache, | |
420 | "Rename failed with error %d", ret); | |
421 | ||
422 | if (preemptive) | |
423 | cachefiles_mark_object_buried(cache, rep, why); | |
424 | } | |
425 | ||
426 | unlock_rename(cache->graveyard, dir); | |
427 | dput(grave); | |
428 | _leave(" = 0"); | |
429 | return 0; | |
430 | } | |
431 | ||
432 | /* | |
433 | * delete an object representation from the cache | |
434 | */ | |
435 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
436 | struct cachefiles_object *object) | |
437 | { | |
438 | struct dentry *dir; | |
439 | int ret; | |
440 | ||
441 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); | |
442 | ||
443 | ASSERT(object->dentry); | |
444 | ASSERT(d_backing_inode(object->dentry)); | |
445 | ASSERT(object->dentry->d_parent); | |
446 | ||
447 | dir = dget_parent(object->dentry); | |
448 | ||
449 | inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); | |
450 | ||
451 | if (test_bit(FSCACHE_OBJECT_KILLED_BY_CACHE, &object->fscache.flags)) { | |
452 | /* object allocation for the same key preemptively deleted this | |
453 | * object's file so that it could create its own file */ | |
454 | _debug("object preemptively buried"); | |
455 | inode_unlock(d_inode(dir)); | |
456 | ret = 0; | |
457 | } else { | |
458 | /* we need to check that our parent is _still_ our parent - it | |
459 | * may have been renamed */ | |
460 | if (dir == object->dentry->d_parent) { | |
461 | ret = cachefiles_bury_object(cache, dir, | |
462 | object->dentry, false, | |
463 | FSCACHE_OBJECT_WAS_RETIRED); | |
464 | } else { | |
465 | /* it got moved, presumably by cachefilesd culling it, | |
466 | * so it's no longer in the key path and we can ignore | |
467 | * it */ | |
468 | inode_unlock(d_inode(dir)); | |
469 | ret = 0; | |
470 | } | |
471 | } | |
472 | ||
473 | dput(dir); | |
474 | _leave(" = %d", ret); | |
475 | return ret; | |
476 | } | |
477 | ||
478 | /* | |
479 | * walk from the parent object to the child object through the backing | |
480 | * filesystem, creating directories as we go | |
481 | */ | |
482 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
483 | struct cachefiles_object *object, | |
484 | const char *key, | |
485 | struct cachefiles_xattr *auxdata) | |
486 | { | |
487 | struct cachefiles_cache *cache; | |
488 | struct dentry *dir, *next = NULL; | |
489 | struct path path; | |
490 | unsigned long start; | |
491 | const char *name; | |
492 | int ret, nlen; | |
493 | ||
494 | _enter("OBJ%x{%p},OBJ%x,%s,", | |
495 | parent->fscache.debug_id, parent->dentry, | |
496 | object->fscache.debug_id, key); | |
497 | ||
498 | cache = container_of(parent->fscache.cache, | |
499 | struct cachefiles_cache, cache); | |
500 | path.mnt = cache->mnt; | |
501 | ||
502 | ASSERT(parent->dentry); | |
503 | ASSERT(d_backing_inode(parent->dentry)); | |
504 | ||
505 | if (!(d_is_dir(parent->dentry))) { | |
506 | // TODO: convert file to dir | |
507 | _leave("looking up in none directory"); | |
508 | return -ENOBUFS; | |
509 | } | |
510 | ||
511 | dir = dget(parent->dentry); | |
512 | ||
513 | advance: | |
514 | /* attempt to transit the first directory component */ | |
515 | name = key; | |
516 | nlen = strlen(key); | |
517 | ||
518 | /* key ends in a double NUL */ | |
519 | key = key + nlen + 1; | |
520 | if (!*key) | |
521 | key = NULL; | |
522 | ||
523 | lookup_again: | |
524 | /* search the current directory for the element name */ | |
525 | _debug("lookup '%s'", name); | |
526 | ||
527 | inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); | |
528 | ||
529 | start = jiffies; | |
530 | next = lookup_one_len(name, dir, nlen); | |
531 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
532 | if (IS_ERR(next)) | |
533 | goto lookup_error; | |
534 | ||
535 | _debug("next -> %p %s", next, d_backing_inode(next) ? "positive" : "negative"); | |
536 | ||
537 | if (!key) | |
538 | object->new = !d_backing_inode(next); | |
539 | ||
540 | /* if this element of the path doesn't exist, then the lookup phase | |
541 | * failed, and we can release any readers in the certain knowledge that | |
542 | * there's nothing for them to actually read */ | |
543 | if (d_is_negative(next)) | |
544 | fscache_object_lookup_negative(&object->fscache); | |
545 | ||
546 | /* we need to create the object if it's negative */ | |
547 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
548 | /* index objects and intervening tree levels must be subdirs */ | |
549 | if (d_is_negative(next)) { | |
550 | ret = cachefiles_has_space(cache, 1, 0); | |
551 | if (ret < 0) | |
552 | goto no_space_error; | |
553 | ||
554 | path.dentry = dir; | |
555 | ret = security_path_mkdir(&path, next, 0); | |
556 | if (ret < 0) | |
557 | goto create_error; | |
558 | start = jiffies; | |
559 | ret = vfs_mkdir(d_inode(dir), next, 0); | |
560 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
561 | if (ret < 0) | |
562 | goto create_error; | |
563 | ||
564 | ASSERT(d_backing_inode(next)); | |
565 | ||
566 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
567 | next, d_backing_inode(next), d_backing_inode(next)->i_ino); | |
568 | ||
569 | } else if (!d_can_lookup(next)) { | |
570 | pr_err("inode %lu is not a directory\n", | |
571 | d_backing_inode(next)->i_ino); | |
572 | ret = -ENOBUFS; | |
573 | goto error; | |
574 | } | |
575 | ||
576 | } else { | |
577 | /* non-index objects start out life as files */ | |
578 | if (d_is_negative(next)) { | |
579 | ret = cachefiles_has_space(cache, 1, 0); | |
580 | if (ret < 0) | |
581 | goto no_space_error; | |
582 | ||
583 | path.dentry = dir; | |
584 | ret = security_path_mknod(&path, next, S_IFREG, 0); | |
585 | if (ret < 0) | |
586 | goto create_error; | |
587 | start = jiffies; | |
588 | ret = vfs_create(d_inode(dir), next, S_IFREG, true); | |
589 | cachefiles_hist(cachefiles_create_histogram, start); | |
590 | if (ret < 0) | |
591 | goto create_error; | |
592 | ||
593 | ASSERT(d_backing_inode(next)); | |
594 | ||
595 | _debug("create -> %p{%p{ino=%lu}}", | |
596 | next, d_backing_inode(next), d_backing_inode(next)->i_ino); | |
597 | ||
598 | } else if (!d_can_lookup(next) && | |
599 | !d_is_reg(next) | |
600 | ) { | |
601 | pr_err("inode %lu is not a file or directory\n", | |
602 | d_backing_inode(next)->i_ino); | |
603 | ret = -ENOBUFS; | |
604 | goto error; | |
605 | } | |
606 | } | |
607 | ||
608 | /* process the next component */ | |
609 | if (key) { | |
610 | _debug("advance"); | |
611 | inode_unlock(d_inode(dir)); | |
612 | dput(dir); | |
613 | dir = next; | |
614 | next = NULL; | |
615 | goto advance; | |
616 | } | |
617 | ||
618 | /* we've found the object we were looking for */ | |
619 | object->dentry = next; | |
620 | ||
621 | /* if we've found that the terminal object exists, then we need to | |
622 | * check its attributes and delete it if it's out of date */ | |
623 | if (!object->new) { | |
624 | _debug("validate '%pd'", next); | |
625 | ||
626 | ret = cachefiles_check_object_xattr(object, auxdata); | |
627 | if (ret == -ESTALE) { | |
628 | /* delete the object (the deleter drops the directory | |
629 | * mutex) */ | |
630 | object->dentry = NULL; | |
631 | ||
632 | ret = cachefiles_bury_object(cache, dir, next, true, | |
633 | FSCACHE_OBJECT_IS_STALE); | |
634 | dput(next); | |
635 | next = NULL; | |
636 | ||
637 | if (ret < 0) | |
638 | goto delete_error; | |
639 | ||
640 | _debug("redo lookup"); | |
641 | fscache_object_retrying_stale(&object->fscache); | |
642 | goto lookup_again; | |
643 | } | |
644 | } | |
645 | ||
646 | /* note that we're now using this object */ | |
647 | ret = cachefiles_mark_object_active(cache, object); | |
648 | ||
649 | inode_unlock(d_inode(dir)); | |
650 | dput(dir); | |
651 | dir = NULL; | |
652 | ||
653 | if (ret == -ETIMEDOUT) | |
654 | goto mark_active_timed_out; | |
655 | ||
656 | _debug("=== OBTAINED_OBJECT ==="); | |
657 | ||
658 | if (object->new) { | |
659 | /* attach data to a newly constructed terminal object */ | |
660 | ret = cachefiles_set_object_xattr(object, auxdata); | |
661 | if (ret < 0) | |
662 | goto check_error; | |
663 | } else { | |
664 | /* always update the atime on an object we've just looked up | |
665 | * (this is used to keep track of culling, and atimes are only | |
666 | * updated by read, write and readdir but not lookup or | |
667 | * open) */ | |
668 | path.dentry = next; | |
669 | touch_atime(&path); | |
670 | } | |
671 | ||
672 | /* open a file interface onto a data file */ | |
673 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
674 | if (d_is_reg(object->dentry)) { | |
675 | const struct address_space_operations *aops; | |
676 | ||
677 | ret = -EPERM; | |
678 | aops = d_backing_inode(object->dentry)->i_mapping->a_ops; | |
679 | if (!aops->bmap) | |
680 | goto check_error; | |
681 | if (object->dentry->d_sb->s_blocksize > PAGE_SIZE) | |
682 | goto check_error; | |
683 | ||
684 | object->backer = object->dentry; | |
685 | } else { | |
686 | BUG(); // TODO: open file in data-class subdir | |
687 | } | |
688 | } | |
689 | ||
690 | object->new = 0; | |
691 | fscache_obtained_object(&object->fscache); | |
692 | ||
693 | _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino); | |
694 | return 0; | |
695 | ||
696 | no_space_error: | |
697 | fscache_object_mark_killed(&object->fscache, FSCACHE_OBJECT_NO_SPACE); | |
698 | create_error: | |
699 | _debug("create error %d", ret); | |
700 | if (ret == -EIO) | |
701 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
702 | goto error; | |
703 | ||
704 | mark_active_timed_out: | |
705 | _debug("mark active timed out"); | |
706 | goto release_dentry; | |
707 | ||
708 | check_error: | |
709 | _debug("check error %d", ret); | |
710 | cachefiles_mark_object_inactive( | |
711 | cache, object, d_backing_inode(object->dentry)->i_blocks); | |
712 | release_dentry: | |
713 | dput(object->dentry); | |
714 | object->dentry = NULL; | |
715 | goto error_out; | |
716 | ||
717 | delete_error: | |
718 | _debug("delete error %d", ret); | |
719 | goto error_out2; | |
720 | ||
721 | lookup_error: | |
722 | _debug("lookup error %ld", PTR_ERR(next)); | |
723 | ret = PTR_ERR(next); | |
724 | if (ret == -EIO) | |
725 | cachefiles_io_error(cache, "Lookup failed"); | |
726 | next = NULL; | |
727 | error: | |
728 | inode_unlock(d_inode(dir)); | |
729 | dput(next); | |
730 | error_out2: | |
731 | dput(dir); | |
732 | error_out: | |
733 | _leave(" = error %d", -ret); | |
734 | return ret; | |
735 | } | |
736 | ||
737 | /* | |
738 | * get a subdirectory | |
739 | */ | |
740 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
741 | struct dentry *dir, | |
742 | const char *dirname) | |
743 | { | |
744 | struct dentry *subdir; | |
745 | unsigned long start; | |
746 | struct path path; | |
747 | int ret; | |
748 | ||
749 | _enter(",,%s", dirname); | |
750 | ||
751 | /* search the current directory for the element name */ | |
752 | inode_lock(d_inode(dir)); | |
753 | ||
754 | start = jiffies; | |
755 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
756 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
757 | if (IS_ERR(subdir)) { | |
758 | if (PTR_ERR(subdir) == -ENOMEM) | |
759 | goto nomem_d_alloc; | |
760 | goto lookup_error; | |
761 | } | |
762 | ||
763 | _debug("subdir -> %p %s", | |
764 | subdir, d_backing_inode(subdir) ? "positive" : "negative"); | |
765 | ||
766 | /* we need to create the subdir if it doesn't exist yet */ | |
767 | if (d_is_negative(subdir)) { | |
768 | ret = cachefiles_has_space(cache, 1, 0); | |
769 | if (ret < 0) | |
770 | goto mkdir_error; | |
771 | ||
772 | _debug("attempt mkdir"); | |
773 | ||
774 | path.mnt = cache->mnt; | |
775 | path.dentry = dir; | |
776 | ret = security_path_mkdir(&path, subdir, 0700); | |
777 | if (ret < 0) | |
778 | goto mkdir_error; | |
779 | ret = vfs_mkdir(d_inode(dir), subdir, 0700); | |
780 | if (ret < 0) | |
781 | goto mkdir_error; | |
782 | ||
783 | ASSERT(d_backing_inode(subdir)); | |
784 | ||
785 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
786 | subdir, | |
787 | d_backing_inode(subdir), | |
788 | d_backing_inode(subdir)->i_ino); | |
789 | } | |
790 | ||
791 | inode_unlock(d_inode(dir)); | |
792 | ||
793 | /* we need to make sure the subdir is a directory */ | |
794 | ASSERT(d_backing_inode(subdir)); | |
795 | ||
796 | if (!d_can_lookup(subdir)) { | |
797 | pr_err("%s is not a directory\n", dirname); | |
798 | ret = -EIO; | |
799 | goto check_error; | |
800 | } | |
801 | ||
802 | ret = -EPERM; | |
803 | if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) || | |
804 | !d_backing_inode(subdir)->i_op->lookup || | |
805 | !d_backing_inode(subdir)->i_op->mkdir || | |
806 | !d_backing_inode(subdir)->i_op->create || | |
807 | !d_backing_inode(subdir)->i_op->rename || | |
808 | !d_backing_inode(subdir)->i_op->rmdir || | |
809 | !d_backing_inode(subdir)->i_op->unlink) | |
810 | goto check_error; | |
811 | ||
812 | _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); | |
813 | return subdir; | |
814 | ||
815 | check_error: | |
816 | dput(subdir); | |
817 | _leave(" = %d [check]", ret); | |
818 | return ERR_PTR(ret); | |
819 | ||
820 | mkdir_error: | |
821 | inode_unlock(d_inode(dir)); | |
822 | dput(subdir); | |
823 | pr_err("mkdir %s failed with error %d\n", dirname, ret); | |
824 | return ERR_PTR(ret); | |
825 | ||
826 | lookup_error: | |
827 | inode_unlock(d_inode(dir)); | |
828 | ret = PTR_ERR(subdir); | |
829 | pr_err("Lookup %s failed with error %d\n", dirname, ret); | |
830 | return ERR_PTR(ret); | |
831 | ||
832 | nomem_d_alloc: | |
833 | inode_unlock(d_inode(dir)); | |
834 | _leave(" = -ENOMEM"); | |
835 | return ERR_PTR(-ENOMEM); | |
836 | } | |
837 | ||
838 | /* | |
839 | * find out if an object is in use or not | |
840 | * - if finds object and it's not in use: | |
841 | * - returns a pointer to the object and a reference on it | |
842 | * - returns with the directory locked | |
843 | */ | |
844 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
845 | struct dentry *dir, | |
846 | char *filename) | |
847 | { | |
848 | struct cachefiles_object *object; | |
849 | struct rb_node *_n; | |
850 | struct dentry *victim; | |
851 | unsigned long start; | |
852 | int ret; | |
853 | ||
854 | //_enter(",%pd/,%s", | |
855 | // dir, filename); | |
856 | ||
857 | /* look up the victim */ | |
858 | inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); | |
859 | ||
860 | start = jiffies; | |
861 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
862 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
863 | if (IS_ERR(victim)) | |
864 | goto lookup_error; | |
865 | ||
866 | //_debug("victim -> %p %s", | |
867 | // victim, d_backing_inode(victim) ? "positive" : "negative"); | |
868 | ||
869 | /* if the object is no longer there then we probably retired the object | |
870 | * at the netfs's request whilst the cull was in progress | |
871 | */ | |
872 | if (d_is_negative(victim)) { | |
873 | inode_unlock(d_inode(dir)); | |
874 | dput(victim); | |
875 | _leave(" = -ENOENT [absent]"); | |
876 | return ERR_PTR(-ENOENT); | |
877 | } | |
878 | ||
879 | /* check to see if we're using this object */ | |
880 | read_lock(&cache->active_lock); | |
881 | ||
882 | _n = cache->active_nodes.rb_node; | |
883 | ||
884 | while (_n) { | |
885 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
886 | ||
887 | if (object->dentry > victim) | |
888 | _n = _n->rb_left; | |
889 | else if (object->dentry < victim) | |
890 | _n = _n->rb_right; | |
891 | else | |
892 | goto object_in_use; | |
893 | } | |
894 | ||
895 | read_unlock(&cache->active_lock); | |
896 | ||
897 | //_leave(" = %p", victim); | |
898 | return victim; | |
899 | ||
900 | object_in_use: | |
901 | read_unlock(&cache->active_lock); | |
902 | inode_unlock(d_inode(dir)); | |
903 | dput(victim); | |
904 | //_leave(" = -EBUSY [in use]"); | |
905 | return ERR_PTR(-EBUSY); | |
906 | ||
907 | lookup_error: | |
908 | inode_unlock(d_inode(dir)); | |
909 | ret = PTR_ERR(victim); | |
910 | if (ret == -ENOENT) { | |
911 | /* file or dir now absent - probably retired by netfs */ | |
912 | _leave(" = -ESTALE [absent]"); | |
913 | return ERR_PTR(-ESTALE); | |
914 | } | |
915 | ||
916 | if (ret == -EIO) { | |
917 | cachefiles_io_error(cache, "Lookup failed"); | |
918 | } else if (ret != -ENOMEM) { | |
919 | pr_err("Internal error: %d\n", ret); | |
920 | ret = -EIO; | |
921 | } | |
922 | ||
923 | _leave(" = %d", ret); | |
924 | return ERR_PTR(ret); | |
925 | } | |
926 | ||
927 | /* | |
928 | * cull an object if it's not in use | |
929 | * - called only by cache manager daemon | |
930 | */ | |
931 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
932 | char *filename) | |
933 | { | |
934 | struct dentry *victim; | |
935 | int ret; | |
936 | ||
937 | _enter(",%pd/,%s", dir, filename); | |
938 | ||
939 | victim = cachefiles_check_active(cache, dir, filename); | |
940 | if (IS_ERR(victim)) | |
941 | return PTR_ERR(victim); | |
942 | ||
943 | _debug("victim -> %p %s", | |
944 | victim, d_backing_inode(victim) ? "positive" : "negative"); | |
945 | ||
946 | /* okay... the victim is not being used so we can cull it | |
947 | * - start by marking it as stale | |
948 | */ | |
949 | _debug("victim is cullable"); | |
950 | ||
951 | ret = cachefiles_remove_object_xattr(cache, victim); | |
952 | if (ret < 0) | |
953 | goto error_unlock; | |
954 | ||
955 | /* actually remove the victim (drops the dir mutex) */ | |
956 | _debug("bury"); | |
957 | ||
958 | ret = cachefiles_bury_object(cache, dir, victim, false, | |
959 | FSCACHE_OBJECT_WAS_CULLED); | |
960 | if (ret < 0) | |
961 | goto error; | |
962 | ||
963 | dput(victim); | |
964 | _leave(" = 0"); | |
965 | return 0; | |
966 | ||
967 | error_unlock: | |
968 | inode_unlock(d_inode(dir)); | |
969 | error: | |
970 | dput(victim); | |
971 | if (ret == -ENOENT) { | |
972 | /* file or dir now absent - probably retired by netfs */ | |
973 | _leave(" = -ESTALE [absent]"); | |
974 | return -ESTALE; | |
975 | } | |
976 | ||
977 | if (ret != -ENOMEM) { | |
978 | pr_err("Internal error: %d\n", ret); | |
979 | ret = -EIO; | |
980 | } | |
981 | ||
982 | _leave(" = %d", ret); | |
983 | return ret; | |
984 | } | |
985 | ||
986 | /* | |
987 | * find out if an object is in use or not | |
988 | * - called only by cache manager daemon | |
989 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
990 | */ | |
991 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
992 | char *filename) | |
993 | { | |
994 | struct dentry *victim; | |
995 | ||
996 | //_enter(",%pd/,%s", | |
997 | // dir, filename); | |
998 | ||
999 | victim = cachefiles_check_active(cache, dir, filename); | |
1000 | if (IS_ERR(victim)) | |
1001 | return PTR_ERR(victim); | |
1002 | ||
1003 | inode_unlock(d_inode(dir)); | |
1004 | dput(victim); | |
1005 | //_leave(" = 0"); | |
1006 | return 0; | |
1007 | } |