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9ae326a6 DH |
1 | /* FS-Cache interface to CacheFiles |
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 | ||
5a0e3ad6 | 12 | #include <linux/slab.h> |
9ae326a6 | 13 | #include <linux/mount.h> |
9ae326a6 DH |
14 | #include "internal.h" |
15 | ||
9ae326a6 DH |
16 | struct cachefiles_lookup_data { |
17 | struct cachefiles_xattr *auxdata; /* auxiliary data */ | |
18 | char *key; /* key path */ | |
19 | }; | |
20 | ||
21 | static int cachefiles_attr_changed(struct fscache_object *_object); | |
22 | ||
23 | /* | |
24 | * allocate an object record for a cookie lookup and prepare the lookup data | |
25 | */ | |
26 | static struct fscache_object *cachefiles_alloc_object( | |
27 | struct fscache_cache *_cache, | |
28 | struct fscache_cookie *cookie) | |
29 | { | |
30 | struct cachefiles_lookup_data *lookup_data; | |
31 | struct cachefiles_object *object; | |
32 | struct cachefiles_cache *cache; | |
33 | struct cachefiles_xattr *auxdata; | |
34 | unsigned keylen, auxlen; | |
35 | void *buffer; | |
36 | char *key; | |
37 | ||
38 | cache = container_of(_cache, struct cachefiles_cache, cache); | |
39 | ||
40 | _enter("{%s},%p,", cache->cache.identifier, cookie); | |
41 | ||
5f4f9f4a | 42 | lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp); |
9ae326a6 DH |
43 | if (!lookup_data) |
44 | goto nomem_lookup_data; | |
45 | ||
46 | /* create a new object record and a temporary leaf image */ | |
5f4f9f4a | 47 | object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp); |
9ae326a6 DH |
48 | if (!object) |
49 | goto nomem_object; | |
50 | ||
51 | ASSERTCMP(object->backer, ==, NULL); | |
52 | ||
53 | BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); | |
54 | atomic_set(&object->usage, 1); | |
55 | ||
56 | fscache_object_init(&object->fscache, cookie, &cache->cache); | |
57 | ||
58 | object->type = cookie->def->type; | |
59 | ||
60 | /* get hold of the raw key | |
61 | * - stick the length on the front and leave space on the back for the | |
62 | * encoder | |
63 | */ | |
5f4f9f4a | 64 | buffer = kmalloc((2 + 512) + 3, cachefiles_gfp); |
9ae326a6 DH |
65 | if (!buffer) |
66 | goto nomem_buffer; | |
67 | ||
68 | keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512); | |
69 | ASSERTCMP(keylen, <, 512); | |
70 | ||
71 | *(uint16_t *)buffer = keylen; | |
72 | ((char *)buffer)[keylen + 2] = 0; | |
73 | ((char *)buffer)[keylen + 3] = 0; | |
74 | ((char *)buffer)[keylen + 4] = 0; | |
75 | ||
76 | /* turn the raw key into something that can work with as a filename */ | |
77 | key = cachefiles_cook_key(buffer, keylen + 2, object->type); | |
78 | if (!key) | |
79 | goto nomem_key; | |
80 | ||
81 | /* get hold of the auxiliary data and prepend the object type */ | |
82 | auxdata = buffer; | |
83 | auxlen = 0; | |
84 | if (cookie->def->get_aux) { | |
85 | auxlen = cookie->def->get_aux(cookie->netfs_data, | |
86 | auxdata->data, 511); | |
87 | ASSERTCMP(auxlen, <, 511); | |
88 | } | |
89 | ||
90 | auxdata->len = auxlen + 1; | |
91 | auxdata->type = cookie->def->type; | |
92 | ||
93 | lookup_data->auxdata = auxdata; | |
94 | lookup_data->key = key; | |
95 | object->lookup_data = lookup_data; | |
96 | ||
97 | _leave(" = %p [%p]", &object->fscache, lookup_data); | |
98 | return &object->fscache; | |
99 | ||
100 | nomem_key: | |
101 | kfree(buffer); | |
102 | nomem_buffer: | |
103 | BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); | |
104 | kmem_cache_free(cachefiles_object_jar, object); | |
105 | fscache_object_destroyed(&cache->cache); | |
106 | nomem_object: | |
107 | kfree(lookup_data); | |
108 | nomem_lookup_data: | |
109 | _leave(" = -ENOMEM"); | |
110 | return ERR_PTR(-ENOMEM); | |
111 | } | |
112 | ||
113 | /* | |
114 | * attempt to look up the nominated node in this cache | |
fee096de | 115 | * - return -ETIMEDOUT to be scheduled again |
9ae326a6 | 116 | */ |
fee096de | 117 | static int cachefiles_lookup_object(struct fscache_object *_object) |
9ae326a6 DH |
118 | { |
119 | struct cachefiles_lookup_data *lookup_data; | |
120 | struct cachefiles_object *parent, *object; | |
121 | struct cachefiles_cache *cache; | |
122 | const struct cred *saved_cred; | |
123 | int ret; | |
124 | ||
125 | _enter("{OBJ%x}", _object->debug_id); | |
126 | ||
127 | cache = container_of(_object->cache, struct cachefiles_cache, cache); | |
128 | parent = container_of(_object->parent, | |
129 | struct cachefiles_object, fscache); | |
130 | object = container_of(_object, struct cachefiles_object, fscache); | |
131 | lookup_data = object->lookup_data; | |
132 | ||
133 | ASSERTCMP(lookup_data, !=, NULL); | |
134 | ||
135 | /* look up the key, creating any missing bits */ | |
136 | cachefiles_begin_secure(cache, &saved_cred); | |
137 | ret = cachefiles_walk_to_object(parent, object, | |
138 | lookup_data->key, | |
139 | lookup_data->auxdata); | |
140 | cachefiles_end_secure(cache, saved_cred); | |
141 | ||
142 | /* polish off by setting the attributes of non-index files */ | |
143 | if (ret == 0 && | |
144 | object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX) | |
145 | cachefiles_attr_changed(&object->fscache); | |
146 | ||
fee096de | 147 | if (ret < 0 && ret != -ETIMEDOUT) { |
14e69647 | 148 | if (ret != -ENOBUFS) |
4e1eb883 | 149 | pr_warn("CacheFiles: Lookup failed error %d\n", ret); |
9ae326a6 DH |
150 | fscache_object_lookup_error(&object->fscache); |
151 | } | |
152 | ||
153 | _leave(" [%d]", ret); | |
fee096de | 154 | return ret; |
9ae326a6 DH |
155 | } |
156 | ||
157 | /* | |
158 | * indication of lookup completion | |
159 | */ | |
160 | static void cachefiles_lookup_complete(struct fscache_object *_object) | |
161 | { | |
162 | struct cachefiles_object *object; | |
163 | ||
164 | object = container_of(_object, struct cachefiles_object, fscache); | |
165 | ||
166 | _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data); | |
167 | ||
168 | if (object->lookup_data) { | |
169 | kfree(object->lookup_data->key); | |
170 | kfree(object->lookup_data->auxdata); | |
171 | kfree(object->lookup_data); | |
172 | object->lookup_data = NULL; | |
173 | } | |
174 | } | |
175 | ||
176 | /* | |
177 | * increment the usage count on an inode object (may fail if unmounting) | |
178 | */ | |
179 | static | |
180 | struct fscache_object *cachefiles_grab_object(struct fscache_object *_object) | |
181 | { | |
182 | struct cachefiles_object *object = | |
183 | container_of(_object, struct cachefiles_object, fscache); | |
184 | ||
185 | _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage)); | |
186 | ||
187 | #ifdef CACHEFILES_DEBUG_SLAB | |
188 | ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); | |
189 | #endif | |
190 | ||
191 | atomic_inc(&object->usage); | |
192 | return &object->fscache; | |
193 | } | |
194 | ||
195 | /* | |
25985edc | 196 | * update the auxiliary data for an object object on disk |
9ae326a6 DH |
197 | */ |
198 | static void cachefiles_update_object(struct fscache_object *_object) | |
199 | { | |
200 | struct cachefiles_object *object; | |
201 | struct cachefiles_xattr *auxdata; | |
202 | struct cachefiles_cache *cache; | |
203 | struct fscache_cookie *cookie; | |
204 | const struct cred *saved_cred; | |
205 | unsigned auxlen; | |
206 | ||
207 | _enter("{OBJ%x}", _object->debug_id); | |
208 | ||
209 | object = container_of(_object, struct cachefiles_object, fscache); | |
210 | cache = container_of(object->fscache.cache, struct cachefiles_cache, | |
211 | cache); | |
1362729b DH |
212 | |
213 | if (!fscache_use_cookie(_object)) { | |
214 | _leave(" [relinq]"); | |
215 | return; | |
216 | } | |
217 | ||
9ae326a6 DH |
218 | cookie = object->fscache.cookie; |
219 | ||
220 | if (!cookie->def->get_aux) { | |
1362729b | 221 | fscache_unuse_cookie(_object); |
9ae326a6 DH |
222 | _leave(" [no aux]"); |
223 | return; | |
224 | } | |
225 | ||
5f4f9f4a | 226 | auxdata = kmalloc(2 + 512 + 3, cachefiles_gfp); |
9ae326a6 | 227 | if (!auxdata) { |
1362729b | 228 | fscache_unuse_cookie(_object); |
9ae326a6 DH |
229 | _leave(" [nomem]"); |
230 | return; | |
231 | } | |
232 | ||
233 | auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511); | |
1362729b | 234 | fscache_unuse_cookie(_object); |
9ae326a6 DH |
235 | ASSERTCMP(auxlen, <, 511); |
236 | ||
237 | auxdata->len = auxlen + 1; | |
238 | auxdata->type = cookie->def->type; | |
239 | ||
240 | cachefiles_begin_secure(cache, &saved_cred); | |
241 | cachefiles_update_object_xattr(object, auxdata); | |
242 | cachefiles_end_secure(cache, saved_cred); | |
243 | kfree(auxdata); | |
244 | _leave(""); | |
245 | } | |
246 | ||
247 | /* | |
248 | * discard the resources pinned by an object and effect retirement if | |
249 | * requested | |
250 | */ | |
251 | static void cachefiles_drop_object(struct fscache_object *_object) | |
252 | { | |
253 | struct cachefiles_object *object; | |
254 | struct cachefiles_cache *cache; | |
255 | const struct cred *saved_cred; | |
256 | ||
257 | ASSERT(_object); | |
258 | ||
259 | object = container_of(_object, struct cachefiles_object, fscache); | |
260 | ||
261 | _enter("{OBJ%x,%d}", | |
262 | object->fscache.debug_id, atomic_read(&object->usage)); | |
263 | ||
264 | cache = container_of(object->fscache.cache, | |
265 | struct cachefiles_cache, cache); | |
266 | ||
267 | #ifdef CACHEFILES_DEBUG_SLAB | |
268 | ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); | |
269 | #endif | |
270 | ||
271 | /* delete retired objects */ | |
94d30ae9 | 272 | if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) && |
9ae326a6 DH |
273 | _object != cache->cache.fsdef |
274 | ) { | |
275 | _debug("- retire object OBJ%x", object->fscache.debug_id); | |
276 | cachefiles_begin_secure(cache, &saved_cred); | |
277 | cachefiles_delete_object(cache, object); | |
278 | cachefiles_end_secure(cache, saved_cred); | |
279 | } | |
280 | ||
281 | /* close the filesystem stuff attached to the object */ | |
282 | if (object->backer != object->dentry) | |
283 | dput(object->backer); | |
284 | object->backer = NULL; | |
285 | ||
286 | /* note that the object is now inactive */ | |
287 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { | |
288 | write_lock(&cache->active_lock); | |
289 | if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE, | |
290 | &object->flags)) | |
291 | BUG(); | |
292 | rb_erase(&object->active_node, &cache->active_nodes); | |
293 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
294 | write_unlock(&cache->active_lock); | |
295 | } | |
296 | ||
297 | dput(object->dentry); | |
298 | object->dentry = NULL; | |
299 | ||
300 | _leave(""); | |
301 | } | |
302 | ||
303 | /* | |
304 | * dispose of a reference to an object | |
305 | */ | |
306 | static void cachefiles_put_object(struct fscache_object *_object) | |
307 | { | |
308 | struct cachefiles_object *object; | |
309 | struct fscache_cache *cache; | |
310 | ||
311 | ASSERT(_object); | |
312 | ||
313 | object = container_of(_object, struct cachefiles_object, fscache); | |
314 | ||
315 | _enter("{OBJ%x,%d}", | |
316 | object->fscache.debug_id, atomic_read(&object->usage)); | |
317 | ||
318 | #ifdef CACHEFILES_DEBUG_SLAB | |
319 | ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000); | |
320 | #endif | |
321 | ||
322 | ASSERTIFCMP(object->fscache.parent, | |
323 | object->fscache.parent->n_children, >, 0); | |
324 | ||
325 | if (atomic_dec_and_test(&object->usage)) { | |
326 | _debug("- kill object OBJ%x", object->fscache.debug_id); | |
327 | ||
328 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)); | |
329 | ASSERTCMP(object->fscache.parent, ==, NULL); | |
330 | ASSERTCMP(object->backer, ==, NULL); | |
331 | ASSERTCMP(object->dentry, ==, NULL); | |
332 | ASSERTCMP(object->fscache.n_ops, ==, 0); | |
333 | ASSERTCMP(object->fscache.n_children, ==, 0); | |
334 | ||
335 | if (object->lookup_data) { | |
336 | kfree(object->lookup_data->key); | |
337 | kfree(object->lookup_data->auxdata); | |
338 | kfree(object->lookup_data); | |
339 | object->lookup_data = NULL; | |
340 | } | |
341 | ||
342 | cache = object->fscache.cache; | |
4fbf4291 | 343 | fscache_object_destroy(&object->fscache); |
9ae326a6 DH |
344 | kmem_cache_free(cachefiles_object_jar, object); |
345 | fscache_object_destroyed(cache); | |
346 | } | |
347 | ||
348 | _leave(""); | |
349 | } | |
350 | ||
351 | /* | |
352 | * sync a cache | |
353 | */ | |
354 | static void cachefiles_sync_cache(struct fscache_cache *_cache) | |
355 | { | |
356 | struct cachefiles_cache *cache; | |
357 | const struct cred *saved_cred; | |
358 | int ret; | |
359 | ||
360 | _enter("%p", _cache); | |
361 | ||
362 | cache = container_of(_cache, struct cachefiles_cache, cache); | |
363 | ||
364 | /* make sure all pages pinned by operations on behalf of the netfs are | |
365 | * written to disc */ | |
366 | cachefiles_begin_secure(cache, &saved_cred); | |
5af7926f | 367 | down_read(&cache->mnt->mnt_sb->s_umount); |
60b0680f | 368 | ret = sync_filesystem(cache->mnt->mnt_sb); |
5af7926f | 369 | up_read(&cache->mnt->mnt_sb->s_umount); |
9ae326a6 DH |
370 | cachefiles_end_secure(cache, saved_cred); |
371 | ||
372 | if (ret == -EIO) | |
373 | cachefiles_io_error(cache, | |
374 | "Attempt to sync backing fs superblock" | |
375 | " returned error %d", | |
376 | ret); | |
377 | } | |
378 | ||
5002d7be DH |
379 | /* |
380 | * check if the backing cache is updated to FS-Cache | |
381 | * - called by FS-Cache when evaluates if need to invalidate the cache | |
382 | */ | |
383 | static bool cachefiles_check_consistency(struct fscache_operation *op) | |
384 | { | |
385 | struct cachefiles_object *object; | |
386 | struct cachefiles_cache *cache; | |
387 | const struct cred *saved_cred; | |
388 | int ret; | |
389 | ||
390 | _enter("{OBJ%x}", op->object->debug_id); | |
391 | ||
392 | object = container_of(op->object, struct cachefiles_object, fscache); | |
393 | cache = container_of(object->fscache.cache, | |
394 | struct cachefiles_cache, cache); | |
395 | ||
396 | cachefiles_begin_secure(cache, &saved_cred); | |
397 | ret = cachefiles_check_auxdata(object); | |
398 | cachefiles_end_secure(cache, saved_cred); | |
399 | ||
400 | _leave(" = %d", ret); | |
401 | return ret; | |
402 | } | |
403 | ||
9ae326a6 DH |
404 | /* |
405 | * notification the attributes on an object have changed | |
406 | * - called with reads/writes excluded by FS-Cache | |
407 | */ | |
408 | static int cachefiles_attr_changed(struct fscache_object *_object) | |
409 | { | |
410 | struct cachefiles_object *object; | |
411 | struct cachefiles_cache *cache; | |
412 | const struct cred *saved_cred; | |
413 | struct iattr newattrs; | |
414 | uint64_t ni_size; | |
415 | loff_t oi_size; | |
416 | int ret; | |
417 | ||
418 | _object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size); | |
419 | ||
420 | _enter("{OBJ%x},[%llu]", | |
421 | _object->debug_id, (unsigned long long) ni_size); | |
422 | ||
423 | object = container_of(_object, struct cachefiles_object, fscache); | |
424 | cache = container_of(object->fscache.cache, | |
425 | struct cachefiles_cache, cache); | |
426 | ||
427 | if (ni_size == object->i_size) | |
428 | return 0; | |
429 | ||
430 | if (!object->backer) | |
431 | return -ENOBUFS; | |
432 | ||
433 | ASSERT(S_ISREG(object->backer->d_inode->i_mode)); | |
434 | ||
435 | fscache_set_store_limit(&object->fscache, ni_size); | |
436 | ||
437 | oi_size = i_size_read(object->backer->d_inode); | |
438 | if (oi_size == ni_size) | |
439 | return 0; | |
440 | ||
9ae326a6 DH |
441 | cachefiles_begin_secure(cache, &saved_cred); |
442 | mutex_lock(&object->backer->d_inode->i_mutex); | |
a17754fb DH |
443 | |
444 | /* if there's an extension to a partial page at the end of the backing | |
445 | * file, we need to discard the partial page so that we pick up new | |
446 | * data after it */ | |
447 | if (oi_size & ~PAGE_MASK && ni_size > oi_size) { | |
448 | _debug("discard tail %llx", oi_size); | |
449 | newattrs.ia_valid = ATTR_SIZE; | |
450 | newattrs.ia_size = oi_size & PAGE_MASK; | |
27ac0ffe | 451 | ret = notify_change(object->backer, &newattrs, NULL); |
a17754fb DH |
452 | if (ret < 0) |
453 | goto truncate_failed; | |
454 | } | |
455 | ||
456 | newattrs.ia_valid = ATTR_SIZE; | |
457 | newattrs.ia_size = ni_size; | |
27ac0ffe | 458 | ret = notify_change(object->backer, &newattrs, NULL); |
a17754fb DH |
459 | |
460 | truncate_failed: | |
9ae326a6 DH |
461 | mutex_unlock(&object->backer->d_inode->i_mutex); |
462 | cachefiles_end_secure(cache, saved_cred); | |
463 | ||
464 | if (ret == -EIO) { | |
465 | fscache_set_store_limit(&object->fscache, 0); | |
466 | cachefiles_io_error_obj(object, "Size set failed"); | |
467 | ret = -ENOBUFS; | |
468 | } | |
469 | ||
470 | _leave(" = %d", ret); | |
471 | return ret; | |
472 | } | |
473 | ||
9dc8d9bf DH |
474 | /* |
475 | * Invalidate an object | |
476 | */ | |
477 | static void cachefiles_invalidate_object(struct fscache_operation *op) | |
478 | { | |
479 | struct cachefiles_object *object; | |
480 | struct cachefiles_cache *cache; | |
481 | const struct cred *saved_cred; | |
482 | struct path path; | |
483 | uint64_t ni_size; | |
484 | int ret; | |
485 | ||
486 | object = container_of(op->object, struct cachefiles_object, fscache); | |
487 | cache = container_of(object->fscache.cache, | |
488 | struct cachefiles_cache, cache); | |
489 | ||
490 | op->object->cookie->def->get_attr(op->object->cookie->netfs_data, | |
491 | &ni_size); | |
492 | ||
493 | _enter("{OBJ%x},[%llu]", | |
494 | op->object->debug_id, (unsigned long long)ni_size); | |
495 | ||
496 | if (object->backer) { | |
497 | ASSERT(S_ISREG(object->backer->d_inode->i_mode)); | |
498 | ||
499 | fscache_set_store_limit(&object->fscache, ni_size); | |
500 | ||
501 | path.dentry = object->backer; | |
502 | path.mnt = cache->mnt; | |
503 | ||
504 | cachefiles_begin_secure(cache, &saved_cred); | |
505 | ret = vfs_truncate(&path, 0); | |
506 | if (ret == 0) | |
507 | ret = vfs_truncate(&path, ni_size); | |
508 | cachefiles_end_secure(cache, saved_cred); | |
509 | ||
510 | if (ret != 0) { | |
511 | fscache_set_store_limit(&object->fscache, 0); | |
512 | if (ret == -EIO) | |
513 | cachefiles_io_error_obj(object, | |
514 | "Invalidate failed"); | |
515 | } | |
516 | } | |
517 | ||
1f372dff | 518 | fscache_op_complete(op, true); |
9dc8d9bf DH |
519 | _leave(""); |
520 | } | |
521 | ||
9ae326a6 DH |
522 | /* |
523 | * dissociate a cache from all the pages it was backing | |
524 | */ | |
525 | static void cachefiles_dissociate_pages(struct fscache_cache *cache) | |
526 | { | |
527 | _enter(""); | |
528 | } | |
529 | ||
530 | const struct fscache_cache_ops cachefiles_cache_ops = { | |
531 | .name = "cachefiles", | |
532 | .alloc_object = cachefiles_alloc_object, | |
533 | .lookup_object = cachefiles_lookup_object, | |
534 | .lookup_complete = cachefiles_lookup_complete, | |
535 | .grab_object = cachefiles_grab_object, | |
536 | .update_object = cachefiles_update_object, | |
9dc8d9bf | 537 | .invalidate_object = cachefiles_invalidate_object, |
9ae326a6 DH |
538 | .drop_object = cachefiles_drop_object, |
539 | .put_object = cachefiles_put_object, | |
540 | .sync_cache = cachefiles_sync_cache, | |
541 | .attr_changed = cachefiles_attr_changed, | |
542 | .read_or_alloc_page = cachefiles_read_or_alloc_page, | |
543 | .read_or_alloc_pages = cachefiles_read_or_alloc_pages, | |
544 | .allocate_page = cachefiles_allocate_page, | |
545 | .allocate_pages = cachefiles_allocate_pages, | |
546 | .write_page = cachefiles_write_page, | |
547 | .uncache_page = cachefiles_uncache_page, | |
548 | .dissociate_pages = cachefiles_dissociate_pages, | |
5002d7be | 549 | .check_consistency = cachefiles_check_consistency, |
9ae326a6 | 550 | }; |