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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* FS-Cache interface to CacheFiles
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/slab.h>
9#include <linux/mount.h>
10#include "internal.h"
11
12struct cachefiles_lookup_data {
13 struct cachefiles_xattr *auxdata; /* auxiliary data */
14 char *key; /* key path */
15};
16
17static int cachefiles_attr_changed(struct fscache_object *_object);
18
19/*
20 * allocate an object record for a cookie lookup and prepare the lookup data
21 */
22static struct fscache_object *cachefiles_alloc_object(
23 struct fscache_cache *_cache,
24 struct fscache_cookie *cookie)
25{
26 struct cachefiles_lookup_data *lookup_data;
27 struct cachefiles_object *object;
28 struct cachefiles_cache *cache;
29 struct cachefiles_xattr *auxdata;
30 unsigned keylen, auxlen;
31 void *buffer, *p;
32 char *key;
33
34 cache = container_of(_cache, struct cachefiles_cache, cache);
35
36 _enter("{%s},%p,", cache->cache.identifier, cookie);
37
38 lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp);
39 if (!lookup_data)
40 goto nomem_lookup_data;
41
42 /* create a new object record and a temporary leaf image */
43 object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp);
44 if (!object)
45 goto nomem_object;
46
47 ASSERTCMP(object->backer, ==, NULL);
48
49 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
50 atomic_set(&object->usage, 1);
51
52 fscache_object_init(&object->fscache, cookie, &cache->cache);
53
54 object->type = cookie->def->type;
55
56 /* get hold of the raw key
57 * - stick the length on the front and leave space on the back for the
58 * encoder
59 */
60 buffer = kmalloc((2 + 512) + 3, cachefiles_gfp);
61 if (!buffer)
62 goto nomem_buffer;
63
64 keylen = cookie->key_len;
65 if (keylen <= sizeof(cookie->inline_key))
66 p = cookie->inline_key;
67 else
68 p = cookie->key;
69 memcpy(buffer + 2, p, keylen);
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 = cookie->aux_len;
84 if (auxlen) {
85 if (auxlen <= sizeof(cookie->inline_aux))
86 p = cookie->inline_aux;
87 else
88 p = cookie->aux;
89 memcpy(auxdata->data, p, auxlen);
90 }
91
92 auxdata->len = auxlen + 1;
93 auxdata->type = cookie->type;
94
95 lookup_data->auxdata = auxdata;
96 lookup_data->key = key;
97 object->lookup_data = lookup_data;
98
99 _leave(" = %p [%p]", &object->fscache, lookup_data);
100 return &object->fscache;
101
102nomem_key:
103 kfree(buffer);
104nomem_buffer:
105 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
106 kmem_cache_free(cachefiles_object_jar, object);
107 fscache_object_destroyed(&cache->cache);
108nomem_object:
109 kfree(lookup_data);
110nomem_lookup_data:
111 _leave(" = -ENOMEM");
112 return ERR_PTR(-ENOMEM);
113}
114
115/*
116 * attempt to look up the nominated node in this cache
117 * - return -ETIMEDOUT to be scheduled again
118 */
119static int cachefiles_lookup_object(struct fscache_object *_object)
120{
121 struct cachefiles_lookup_data *lookup_data;
122 struct cachefiles_object *parent, *object;
123 struct cachefiles_cache *cache;
124 const struct cred *saved_cred;
125 int ret;
126
127 _enter("{OBJ%x}", _object->debug_id);
128
129 cache = container_of(_object->cache, struct cachefiles_cache, cache);
130 parent = container_of(_object->parent,
131 struct cachefiles_object, fscache);
132 object = container_of(_object, struct cachefiles_object, fscache);
133 lookup_data = object->lookup_data;
134
135 ASSERTCMP(lookup_data, !=, NULL);
136
137 /* look up the key, creating any missing bits */
138 cachefiles_begin_secure(cache, &saved_cred);
139 ret = cachefiles_walk_to_object(parent, object,
140 lookup_data->key,
141 lookup_data->auxdata);
142 cachefiles_end_secure(cache, saved_cred);
143
144 /* polish off by setting the attributes of non-index files */
145 if (ret == 0 &&
146 object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
147 cachefiles_attr_changed(&object->fscache);
148
149 if (ret < 0 && ret != -ETIMEDOUT) {
150 if (ret != -ENOBUFS)
151 pr_warn("Lookup failed error %d\n", ret);
152 fscache_object_lookup_error(&object->fscache);
153 }
154
155 _leave(" [%d]", ret);
156 return ret;
157}
158
159/*
160 * indication of lookup completion
161 */
162static void cachefiles_lookup_complete(struct fscache_object *_object)
163{
164 struct cachefiles_object *object;
165
166 object = container_of(_object, struct cachefiles_object, fscache);
167
168 _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
169
170 if (object->lookup_data) {
171 kfree(object->lookup_data->key);
172 kfree(object->lookup_data->auxdata);
173 kfree(object->lookup_data);
174 object->lookup_data = NULL;
175 }
176}
177
178/*
179 * increment the usage count on an inode object (may fail if unmounting)
180 */
181static
182struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
183 enum fscache_obj_ref_trace why)
184{
185 struct cachefiles_object *object =
186 container_of(_object, struct cachefiles_object, fscache);
187 int u;
188
189 _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
190
191#ifdef CACHEFILES_DEBUG_SLAB
192 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
193#endif
194
195 u = atomic_inc_return(&object->usage);
196 trace_cachefiles_ref(object, _object->cookie,
197 (enum cachefiles_obj_ref_trace)why, u);
198 return &object->fscache;
199}
200
201/*
202 * update the auxiliary data for an object object on disk
203 */
204static void cachefiles_update_object(struct fscache_object *_object)
205{
206 struct cachefiles_object *object;
207 struct cachefiles_xattr *auxdata;
208 struct cachefiles_cache *cache;
209 struct fscache_cookie *cookie;
210 const struct cred *saved_cred;
211 const void *aux;
212 unsigned auxlen;
213
214 _enter("{OBJ%x}", _object->debug_id);
215
216 object = container_of(_object, struct cachefiles_object, fscache);
217 cache = container_of(object->fscache.cache, struct cachefiles_cache,
218 cache);
219
220 if (!fscache_use_cookie(_object)) {
221 _leave(" [relinq]");
222 return;
223 }
224
225 cookie = object->fscache.cookie;
226 auxlen = cookie->aux_len;
227
228 if (!auxlen) {
229 fscache_unuse_cookie(_object);
230 _leave(" [no aux]");
231 return;
232 }
233
234 auxdata = kmalloc(2 + auxlen + 3, cachefiles_gfp);
235 if (!auxdata) {
236 fscache_unuse_cookie(_object);
237 _leave(" [nomem]");
238 return;
239 }
240
241 aux = (auxlen <= sizeof(cookie->inline_aux)) ?
242 cookie->inline_aux : cookie->aux;
243
244 memcpy(auxdata->data, aux, auxlen);
245 fscache_unuse_cookie(_object);
246
247 auxdata->len = auxlen + 1;
248 auxdata->type = cookie->type;
249
250 cachefiles_begin_secure(cache, &saved_cred);
251 cachefiles_update_object_xattr(object, auxdata);
252 cachefiles_end_secure(cache, saved_cred);
253 kfree(auxdata);
254 _leave("");
255}
256
257/*
258 * discard the resources pinned by an object and effect retirement if
259 * requested
260 */
261static void cachefiles_drop_object(struct fscache_object *_object)
262{
263 struct cachefiles_object *object;
264 struct cachefiles_cache *cache;
265 const struct cred *saved_cred;
266 struct inode *inode;
267 blkcnt_t i_blocks = 0;
268
269 ASSERT(_object);
270
271 object = container_of(_object, struct cachefiles_object, fscache);
272
273 _enter("{OBJ%x,%d}",
274 object->fscache.debug_id, atomic_read(&object->usage));
275
276 cache = container_of(object->fscache.cache,
277 struct cachefiles_cache, cache);
278
279#ifdef CACHEFILES_DEBUG_SLAB
280 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
281#endif
282
283 /* We need to tidy the object up if we did in fact manage to open it.
284 * It's possible for us to get here before the object is fully
285 * initialised if the parent goes away or the object gets retired
286 * before we set it up.
287 */
288 if (object->dentry) {
289 /* delete retired objects */
290 if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
291 _object != cache->cache.fsdef
292 ) {
293 _debug("- retire object OBJ%x", object->fscache.debug_id);
294 inode = d_backing_inode(object->dentry);
295 if (inode)
296 i_blocks = inode->i_blocks;
297
298 cachefiles_begin_secure(cache, &saved_cred);
299 cachefiles_delete_object(cache, object);
300 cachefiles_end_secure(cache, saved_cred);
301 }
302
303 /* close the filesystem stuff attached to the object */
304 if (object->backer != object->dentry)
305 dput(object->backer);
306 object->backer = NULL;
307 }
308
309 /* note that the object is now inactive */
310 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
311 cachefiles_mark_object_inactive(cache, object, i_blocks);
312
313 dput(object->dentry);
314 object->dentry = NULL;
315
316 _leave("");
317}
318
319/*
320 * dispose of a reference to an object
321 */
322static void cachefiles_put_object(struct fscache_object *_object,
323 enum fscache_obj_ref_trace why)
324{
325 struct cachefiles_object *object;
326 struct fscache_cache *cache;
327 int u;
328
329 ASSERT(_object);
330
331 object = container_of(_object, struct cachefiles_object, fscache);
332
333 _enter("{OBJ%x,%d}",
334 object->fscache.debug_id, atomic_read(&object->usage));
335
336#ifdef CACHEFILES_DEBUG_SLAB
337 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
338#endif
339
340 ASSERTIFCMP(object->fscache.parent,
341 object->fscache.parent->n_children, >, 0);
342
343 u = atomic_dec_return(&object->usage);
344 trace_cachefiles_ref(object, _object->cookie,
345 (enum cachefiles_obj_ref_trace)why, u);
346 ASSERTCMP(u, !=, -1);
347 if (u == 0) {
348 _debug("- kill object OBJ%x", object->fscache.debug_id);
349
350 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
351 ASSERTCMP(object->fscache.parent, ==, NULL);
352 ASSERTCMP(object->backer, ==, NULL);
353 ASSERTCMP(object->dentry, ==, NULL);
354 ASSERTCMP(object->fscache.n_ops, ==, 0);
355 ASSERTCMP(object->fscache.n_children, ==, 0);
356
357 if (object->lookup_data) {
358 kfree(object->lookup_data->key);
359 kfree(object->lookup_data->auxdata);
360 kfree(object->lookup_data);
361 object->lookup_data = NULL;
362 }
363
364 cache = object->fscache.cache;
365 fscache_object_destroy(&object->fscache);
366 kmem_cache_free(cachefiles_object_jar, object);
367 fscache_object_destroyed(cache);
368 }
369
370 _leave("");
371}
372
373/*
374 * sync a cache
375 */
376static void cachefiles_sync_cache(struct fscache_cache *_cache)
377{
378 struct cachefiles_cache *cache;
379 const struct cred *saved_cred;
380 int ret;
381
382 _enter("%p", _cache);
383
384 cache = container_of(_cache, struct cachefiles_cache, cache);
385
386 /* make sure all pages pinned by operations on behalf of the netfs are
387 * written to disc */
388 cachefiles_begin_secure(cache, &saved_cred);
389 down_read(&cache->mnt->mnt_sb->s_umount);
390 ret = sync_filesystem(cache->mnt->mnt_sb);
391 up_read(&cache->mnt->mnt_sb->s_umount);
392 cachefiles_end_secure(cache, saved_cred);
393
394 if (ret == -EIO)
395 cachefiles_io_error(cache,
396 "Attempt to sync backing fs superblock"
397 " returned error %d",
398 ret);
399}
400
401/*
402 * check if the backing cache is updated to FS-Cache
403 * - called by FS-Cache when evaluates if need to invalidate the cache
404 */
405static int cachefiles_check_consistency(struct fscache_operation *op)
406{
407 struct cachefiles_object *object;
408 struct cachefiles_cache *cache;
409 const struct cred *saved_cred;
410 int ret;
411
412 _enter("{OBJ%x}", op->object->debug_id);
413
414 object = container_of(op->object, struct cachefiles_object, fscache);
415 cache = container_of(object->fscache.cache,
416 struct cachefiles_cache, cache);
417
418 cachefiles_begin_secure(cache, &saved_cred);
419 ret = cachefiles_check_auxdata(object);
420 cachefiles_end_secure(cache, saved_cred);
421
422 _leave(" = %d", ret);
423 return ret;
424}
425
426/*
427 * notification the attributes on an object have changed
428 * - called with reads/writes excluded by FS-Cache
429 */
430static int cachefiles_attr_changed(struct fscache_object *_object)
431{
432 struct cachefiles_object *object;
433 struct cachefiles_cache *cache;
434 const struct cred *saved_cred;
435 struct iattr newattrs;
436 uint64_t ni_size;
437 loff_t oi_size;
438 int ret;
439
440 ni_size = _object->store_limit_l;
441
442 _enter("{OBJ%x},[%llu]",
443 _object->debug_id, (unsigned long long) ni_size);
444
445 object = container_of(_object, struct cachefiles_object, fscache);
446 cache = container_of(object->fscache.cache,
447 struct cachefiles_cache, cache);
448
449 if (ni_size == object->i_size)
450 return 0;
451
452 if (!object->backer)
453 return -ENOBUFS;
454
455 ASSERT(d_is_reg(object->backer));
456
457 fscache_set_store_limit(&object->fscache, ni_size);
458
459 oi_size = i_size_read(d_backing_inode(object->backer));
460 if (oi_size == ni_size)
461 return 0;
462
463 cachefiles_begin_secure(cache, &saved_cred);
464 inode_lock(d_inode(object->backer));
465
466 /* if there's an extension to a partial page at the end of the backing
467 * file, we need to discard the partial page so that we pick up new
468 * data after it */
469 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
470 _debug("discard tail %llx", oi_size);
471 newattrs.ia_valid = ATTR_SIZE;
472 newattrs.ia_size = oi_size & PAGE_MASK;
473 ret = notify_change(object->backer, &newattrs, NULL);
474 if (ret < 0)
475 goto truncate_failed;
476 }
477
478 newattrs.ia_valid = ATTR_SIZE;
479 newattrs.ia_size = ni_size;
480 ret = notify_change(object->backer, &newattrs, NULL);
481
482truncate_failed:
483 inode_unlock(d_inode(object->backer));
484 cachefiles_end_secure(cache, saved_cred);
485
486 if (ret == -EIO) {
487 fscache_set_store_limit(&object->fscache, 0);
488 cachefiles_io_error_obj(object, "Size set failed");
489 ret = -ENOBUFS;
490 }
491
492 _leave(" = %d", ret);
493 return ret;
494}
495
496/*
497 * Invalidate an object
498 */
499static void cachefiles_invalidate_object(struct fscache_operation *op)
500{
501 struct cachefiles_object *object;
502 struct cachefiles_cache *cache;
503 const struct cred *saved_cred;
504 struct path path;
505 uint64_t ni_size;
506 int ret;
507
508 object = container_of(op->object, struct cachefiles_object, fscache);
509 cache = container_of(object->fscache.cache,
510 struct cachefiles_cache, cache);
511
512 ni_size = op->object->store_limit_l;
513
514 _enter("{OBJ%x},[%llu]",
515 op->object->debug_id, (unsigned long long)ni_size);
516
517 if (object->backer) {
518 ASSERT(d_is_reg(object->backer));
519
520 fscache_set_store_limit(&object->fscache, ni_size);
521
522 path.dentry = object->backer;
523 path.mnt = cache->mnt;
524
525 cachefiles_begin_secure(cache, &saved_cred);
526 ret = vfs_truncate(&path, 0);
527 if (ret == 0)
528 ret = vfs_truncate(&path, ni_size);
529 cachefiles_end_secure(cache, saved_cred);
530
531 if (ret != 0) {
532 fscache_set_store_limit(&object->fscache, 0);
533 if (ret == -EIO)
534 cachefiles_io_error_obj(object,
535 "Invalidate failed");
536 }
537 }
538
539 fscache_op_complete(op, true);
540 _leave("");
541}
542
543/*
544 * dissociate a cache from all the pages it was backing
545 */
546static void cachefiles_dissociate_pages(struct fscache_cache *cache)
547{
548 _enter("");
549}
550
551const struct fscache_cache_ops cachefiles_cache_ops = {
552 .name = "cachefiles",
553 .alloc_object = cachefiles_alloc_object,
554 .lookup_object = cachefiles_lookup_object,
555 .lookup_complete = cachefiles_lookup_complete,
556 .grab_object = cachefiles_grab_object,
557 .update_object = cachefiles_update_object,
558 .invalidate_object = cachefiles_invalidate_object,
559 .drop_object = cachefiles_drop_object,
560 .put_object = cachefiles_put_object,
561 .sync_cache = cachefiles_sync_cache,
562 .attr_changed = cachefiles_attr_changed,
563 .read_or_alloc_page = cachefiles_read_or_alloc_page,
564 .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
565 .allocate_page = cachefiles_allocate_page,
566 .allocate_pages = cachefiles_allocate_pages,
567 .write_page = cachefiles_write_page,
568 .uncache_page = cachefiles_uncache_page,
569 .dissociate_pages = cachefiles_dissociate_pages,
570 .check_consistency = cachefiles_check_consistency,
571};
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
12#include <linux/slab.h>
13#include <linux/mount.h>
14#include <linux/buffer_head.h>
15#include "internal.h"
16
17#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
18
19struct cachefiles_lookup_data {
20 struct cachefiles_xattr *auxdata; /* auxiliary data */
21 char *key; /* key path */
22};
23
24static int cachefiles_attr_changed(struct fscache_object *_object);
25
26/*
27 * allocate an object record for a cookie lookup and prepare the lookup data
28 */
29static struct fscache_object *cachefiles_alloc_object(
30 struct fscache_cache *_cache,
31 struct fscache_cookie *cookie)
32{
33 struct cachefiles_lookup_data *lookup_data;
34 struct cachefiles_object *object;
35 struct cachefiles_cache *cache;
36 struct cachefiles_xattr *auxdata;
37 unsigned keylen, auxlen;
38 void *buffer;
39 char *key;
40
41 cache = container_of(_cache, struct cachefiles_cache, cache);
42
43 _enter("{%s},%p,", cache->cache.identifier, cookie);
44
45 lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
46 if (!lookup_data)
47 goto nomem_lookup_data;
48
49 /* create a new object record and a temporary leaf image */
50 object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
51 if (!object)
52 goto nomem_object;
53
54 ASSERTCMP(object->backer, ==, NULL);
55
56 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
57 atomic_set(&object->usage, 1);
58
59 fscache_object_init(&object->fscache, cookie, &cache->cache);
60
61 object->type = cookie->def->type;
62
63 /* get hold of the raw key
64 * - stick the length on the front and leave space on the back for the
65 * encoder
66 */
67 buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
68 if (!buffer)
69 goto nomem_buffer;
70
71 keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
72 ASSERTCMP(keylen, <, 512);
73
74 *(uint16_t *)buffer = keylen;
75 ((char *)buffer)[keylen + 2] = 0;
76 ((char *)buffer)[keylen + 3] = 0;
77 ((char *)buffer)[keylen + 4] = 0;
78
79 /* turn the raw key into something that can work with as a filename */
80 key = cachefiles_cook_key(buffer, keylen + 2, object->type);
81 if (!key)
82 goto nomem_key;
83
84 /* get hold of the auxiliary data and prepend the object type */
85 auxdata = buffer;
86 auxlen = 0;
87 if (cookie->def->get_aux) {
88 auxlen = cookie->def->get_aux(cookie->netfs_data,
89 auxdata->data, 511);
90 ASSERTCMP(auxlen, <, 511);
91 }
92
93 auxdata->len = auxlen + 1;
94 auxdata->type = cookie->def->type;
95
96 lookup_data->auxdata = auxdata;
97 lookup_data->key = key;
98 object->lookup_data = lookup_data;
99
100 _leave(" = %p [%p]", &object->fscache, lookup_data);
101 return &object->fscache;
102
103nomem_key:
104 kfree(buffer);
105nomem_buffer:
106 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
107 kmem_cache_free(cachefiles_object_jar, object);
108 fscache_object_destroyed(&cache->cache);
109nomem_object:
110 kfree(lookup_data);
111nomem_lookup_data:
112 _leave(" = -ENOMEM");
113 return ERR_PTR(-ENOMEM);
114}
115
116/*
117 * attempt to look up the nominated node in this cache
118 * - return -ETIMEDOUT to be scheduled again
119 */
120static int cachefiles_lookup_object(struct fscache_object *_object)
121{
122 struct cachefiles_lookup_data *lookup_data;
123 struct cachefiles_object *parent, *object;
124 struct cachefiles_cache *cache;
125 const struct cred *saved_cred;
126 int ret;
127
128 _enter("{OBJ%x}", _object->debug_id);
129
130 cache = container_of(_object->cache, struct cachefiles_cache, cache);
131 parent = container_of(_object->parent,
132 struct cachefiles_object, fscache);
133 object = container_of(_object, struct cachefiles_object, fscache);
134 lookup_data = object->lookup_data;
135
136 ASSERTCMP(lookup_data, !=, NULL);
137
138 /* look up the key, creating any missing bits */
139 cachefiles_begin_secure(cache, &saved_cred);
140 ret = cachefiles_walk_to_object(parent, object,
141 lookup_data->key,
142 lookup_data->auxdata);
143 cachefiles_end_secure(cache, saved_cred);
144
145 /* polish off by setting the attributes of non-index files */
146 if (ret == 0 &&
147 object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
148 cachefiles_attr_changed(&object->fscache);
149
150 if (ret < 0 && ret != -ETIMEDOUT) {
151 if (ret != -ENOBUFS)
152 printk(KERN_WARNING
153 "CacheFiles: Lookup failed error %d\n", ret);
154 fscache_object_lookup_error(&object->fscache);
155 }
156
157 _leave(" [%d]", ret);
158 return ret;
159}
160
161/*
162 * indication of lookup completion
163 */
164static void cachefiles_lookup_complete(struct fscache_object *_object)
165{
166 struct cachefiles_object *object;
167
168 object = container_of(_object, struct cachefiles_object, fscache);
169
170 _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
171
172 if (object->lookup_data) {
173 kfree(object->lookup_data->key);
174 kfree(object->lookup_data->auxdata);
175 kfree(object->lookup_data);
176 object->lookup_data = NULL;
177 }
178}
179
180/*
181 * increment the usage count on an inode object (may fail if unmounting)
182 */
183static
184struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
185{
186 struct cachefiles_object *object =
187 container_of(_object, struct cachefiles_object, fscache);
188
189 _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
190
191#ifdef CACHEFILES_DEBUG_SLAB
192 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
193#endif
194
195 atomic_inc(&object->usage);
196 return &object->fscache;
197}
198
199/*
200 * update the auxiliary data for an object object on disk
201 */
202static void cachefiles_update_object(struct fscache_object *_object)
203{
204 struct cachefiles_object *object;
205 struct cachefiles_xattr *auxdata;
206 struct cachefiles_cache *cache;
207 struct fscache_cookie *cookie;
208 const struct cred *saved_cred;
209 unsigned auxlen;
210
211 _enter("{OBJ%x}", _object->debug_id);
212
213 object = container_of(_object, struct cachefiles_object, fscache);
214 cache = container_of(object->fscache.cache, struct cachefiles_cache,
215 cache);
216 cookie = object->fscache.cookie;
217
218 if (!cookie->def->get_aux) {
219 _leave(" [no aux]");
220 return;
221 }
222
223 auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
224 if (!auxdata) {
225 _leave(" [nomem]");
226 return;
227 }
228
229 auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
230 ASSERTCMP(auxlen, <, 511);
231
232 auxdata->len = auxlen + 1;
233 auxdata->type = cookie->def->type;
234
235 cachefiles_begin_secure(cache, &saved_cred);
236 cachefiles_update_object_xattr(object, auxdata);
237 cachefiles_end_secure(cache, saved_cred);
238 kfree(auxdata);
239 _leave("");
240}
241
242/*
243 * discard the resources pinned by an object and effect retirement if
244 * requested
245 */
246static void cachefiles_drop_object(struct fscache_object *_object)
247{
248 struct cachefiles_object *object;
249 struct cachefiles_cache *cache;
250 const struct cred *saved_cred;
251
252 ASSERT(_object);
253
254 object = container_of(_object, struct cachefiles_object, fscache);
255
256 _enter("{OBJ%x,%d}",
257 object->fscache.debug_id, atomic_read(&object->usage));
258
259 cache = container_of(object->fscache.cache,
260 struct cachefiles_cache, cache);
261
262#ifdef CACHEFILES_DEBUG_SLAB
263 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
264#endif
265
266 /* delete retired objects */
267 if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
268 _object != cache->cache.fsdef
269 ) {
270 _debug("- retire object OBJ%x", object->fscache.debug_id);
271 cachefiles_begin_secure(cache, &saved_cred);
272 cachefiles_delete_object(cache, object);
273 cachefiles_end_secure(cache, saved_cred);
274 }
275
276 /* close the filesystem stuff attached to the object */
277 if (object->backer != object->dentry)
278 dput(object->backer);
279 object->backer = NULL;
280
281 /* note that the object is now inactive */
282 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
283 write_lock(&cache->active_lock);
284 if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE,
285 &object->flags))
286 BUG();
287 rb_erase(&object->active_node, &cache->active_nodes);
288 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
289 write_unlock(&cache->active_lock);
290 }
291
292 dput(object->dentry);
293 object->dentry = NULL;
294
295 _leave("");
296}
297
298/*
299 * dispose of a reference to an object
300 */
301static void cachefiles_put_object(struct fscache_object *_object)
302{
303 struct cachefiles_object *object;
304 struct fscache_cache *cache;
305
306 ASSERT(_object);
307
308 object = container_of(_object, struct cachefiles_object, fscache);
309
310 _enter("{OBJ%x,%d}",
311 object->fscache.debug_id, atomic_read(&object->usage));
312
313#ifdef CACHEFILES_DEBUG_SLAB
314 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
315#endif
316
317 ASSERTIFCMP(object->fscache.parent,
318 object->fscache.parent->n_children, >, 0);
319
320 if (atomic_dec_and_test(&object->usage)) {
321 _debug("- kill object OBJ%x", object->fscache.debug_id);
322
323 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
324 ASSERTCMP(object->fscache.parent, ==, NULL);
325 ASSERTCMP(object->backer, ==, NULL);
326 ASSERTCMP(object->dentry, ==, NULL);
327 ASSERTCMP(object->fscache.n_ops, ==, 0);
328 ASSERTCMP(object->fscache.n_children, ==, 0);
329
330 if (object->lookup_data) {
331 kfree(object->lookup_data->key);
332 kfree(object->lookup_data->auxdata);
333 kfree(object->lookup_data);
334 object->lookup_data = NULL;
335 }
336
337 cache = object->fscache.cache;
338 fscache_object_destroy(&object->fscache);
339 kmem_cache_free(cachefiles_object_jar, object);
340 fscache_object_destroyed(cache);
341 }
342
343 _leave("");
344}
345
346/*
347 * sync a cache
348 */
349static void cachefiles_sync_cache(struct fscache_cache *_cache)
350{
351 struct cachefiles_cache *cache;
352 const struct cred *saved_cred;
353 int ret;
354
355 _enter("%p", _cache);
356
357 cache = container_of(_cache, struct cachefiles_cache, cache);
358
359 /* make sure all pages pinned by operations on behalf of the netfs are
360 * written to disc */
361 cachefiles_begin_secure(cache, &saved_cred);
362 down_read(&cache->mnt->mnt_sb->s_umount);
363 ret = sync_filesystem(cache->mnt->mnt_sb);
364 up_read(&cache->mnt->mnt_sb->s_umount);
365 cachefiles_end_secure(cache, saved_cred);
366
367 if (ret == -EIO)
368 cachefiles_io_error(cache,
369 "Attempt to sync backing fs superblock"
370 " returned error %d",
371 ret);
372}
373
374/*
375 * notification the attributes on an object have changed
376 * - called with reads/writes excluded by FS-Cache
377 */
378static int cachefiles_attr_changed(struct fscache_object *_object)
379{
380 struct cachefiles_object *object;
381 struct cachefiles_cache *cache;
382 const struct cred *saved_cred;
383 struct iattr newattrs;
384 uint64_t ni_size;
385 loff_t oi_size;
386 int ret;
387
388 _object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
389
390 _enter("{OBJ%x},[%llu]",
391 _object->debug_id, (unsigned long long) ni_size);
392
393 object = container_of(_object, struct cachefiles_object, fscache);
394 cache = container_of(object->fscache.cache,
395 struct cachefiles_cache, cache);
396
397 if (ni_size == object->i_size)
398 return 0;
399
400 if (!object->backer)
401 return -ENOBUFS;
402
403 ASSERT(S_ISREG(object->backer->d_inode->i_mode));
404
405 fscache_set_store_limit(&object->fscache, ni_size);
406
407 oi_size = i_size_read(object->backer->d_inode);
408 if (oi_size == ni_size)
409 return 0;
410
411 cachefiles_begin_secure(cache, &saved_cred);
412 mutex_lock(&object->backer->d_inode->i_mutex);
413
414 /* if there's an extension to a partial page at the end of the backing
415 * file, we need to discard the partial page so that we pick up new
416 * data after it */
417 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
418 _debug("discard tail %llx", oi_size);
419 newattrs.ia_valid = ATTR_SIZE;
420 newattrs.ia_size = oi_size & PAGE_MASK;
421 ret = notify_change(object->backer, &newattrs);
422 if (ret < 0)
423 goto truncate_failed;
424 }
425
426 newattrs.ia_valid = ATTR_SIZE;
427 newattrs.ia_size = ni_size;
428 ret = notify_change(object->backer, &newattrs);
429
430truncate_failed:
431 mutex_unlock(&object->backer->d_inode->i_mutex);
432 cachefiles_end_secure(cache, saved_cred);
433
434 if (ret == -EIO) {
435 fscache_set_store_limit(&object->fscache, 0);
436 cachefiles_io_error_obj(object, "Size set failed");
437 ret = -ENOBUFS;
438 }
439
440 _leave(" = %d", ret);
441 return ret;
442}
443
444/*
445 * dissociate a cache from all the pages it was backing
446 */
447static void cachefiles_dissociate_pages(struct fscache_cache *cache)
448{
449 _enter("");
450}
451
452const struct fscache_cache_ops cachefiles_cache_ops = {
453 .name = "cachefiles",
454 .alloc_object = cachefiles_alloc_object,
455 .lookup_object = cachefiles_lookup_object,
456 .lookup_complete = cachefiles_lookup_complete,
457 .grab_object = cachefiles_grab_object,
458 .update_object = cachefiles_update_object,
459 .drop_object = cachefiles_drop_object,
460 .put_object = cachefiles_put_object,
461 .sync_cache = cachefiles_sync_cache,
462 .attr_changed = cachefiles_attr_changed,
463 .read_or_alloc_page = cachefiles_read_or_alloc_page,
464 .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
465 .allocate_page = cachefiles_allocate_page,
466 .allocate_pages = cachefiles_allocate_pages,
467 .write_page = cachefiles_write_page,
468 .uncache_page = cachefiles_uncache_page,
469 .dissociate_pages = cachefiles_dissociate_pages,
470};