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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// SPDX-License-Identifier: GPL-2.0-or-later
2/* FS-Cache interface to CacheFiles
3 *
4 * Copyright (C) 2021 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 <linux/xattr.h>
11#include <linux/file.h>
12#include <linux/falloc.h>
13#include <trace/events/fscache.h>
14#include "internal.h"
15
16static atomic_t cachefiles_object_debug_id;
17
18/*
19 * Allocate a cache object record.
20 */
21static
22struct cachefiles_object *cachefiles_alloc_object(struct fscache_cookie *cookie)
23{
24 struct fscache_volume *vcookie = cookie->volume;
25 struct cachefiles_volume *volume = vcookie->cache_priv;
26 struct cachefiles_object *object;
27
28 _enter("{%s},%x,", vcookie->key, cookie->debug_id);
29
30 object = kmem_cache_zalloc(cachefiles_object_jar, GFP_KERNEL);
31 if (!object)
32 return NULL;
33
34 refcount_set(&object->ref, 1);
35
36 spin_lock_init(&object->lock);
37 INIT_LIST_HEAD(&object->cache_link);
38 object->volume = volume;
39 object->debug_id = atomic_inc_return(&cachefiles_object_debug_id);
40 object->cookie = fscache_get_cookie(cookie, fscache_cookie_get_attach_object);
41
42 fscache_count_object(vcookie->cache);
43 trace_cachefiles_ref(object->debug_id, cookie->debug_id, 1,
44 cachefiles_obj_new);
45 return object;
46}
47
48/*
49 * Note that an object has been seen.
50 */
51void cachefiles_see_object(struct cachefiles_object *object,
52 enum cachefiles_obj_ref_trace why)
53{
54 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id,
55 refcount_read(&object->ref), why);
56}
57
58/*
59 * Increment the usage count on an object;
60 */
61struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
62 enum cachefiles_obj_ref_trace why)
63{
64 int r;
65
66 __refcount_inc(&object->ref, &r);
67 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id, r, why);
68 return object;
69}
70
71/*
72 * dispose of a reference to an object
73 */
74void cachefiles_put_object(struct cachefiles_object *object,
75 enum cachefiles_obj_ref_trace why)
76{
77 unsigned int object_debug_id = object->debug_id;
78 unsigned int cookie_debug_id = object->cookie->debug_id;
79 struct fscache_cache *cache;
80 bool done;
81 int r;
82
83 done = __refcount_dec_and_test(&object->ref, &r);
84 trace_cachefiles_ref(object_debug_id, cookie_debug_id, r, why);
85 if (done) {
86 _debug("- kill object OBJ%x", object_debug_id);
87
88 ASSERTCMP(object->file, ==, NULL);
89
90 kfree(object->d_name);
91
92 cache = object->volume->cache->cache;
93 fscache_put_cookie(object->cookie, fscache_cookie_put_object);
94 object->cookie = NULL;
95 kmem_cache_free(cachefiles_object_jar, object);
96 fscache_uncount_object(cache);
97 }
98
99 _leave("");
100}
101
102/*
103 * Adjust the size of a cache file if necessary to match the DIO size. We keep
104 * the EOF marker a multiple of DIO blocks so that we don't fall back to doing
105 * non-DIO for a partial block straddling the EOF, but we also have to be
106 * careful of someone expanding the file and accidentally accreting the
107 * padding.
108 */
109static int cachefiles_adjust_size(struct cachefiles_object *object)
110{
111 struct iattr newattrs;
112 struct file *file = object->file;
113 uint64_t ni_size;
114 loff_t oi_size;
115 int ret;
116
117 ni_size = object->cookie->object_size;
118 ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
119
120 _enter("{OBJ%x},[%llu]",
121 object->debug_id, (unsigned long long) ni_size);
122
123 if (!file)
124 return -ENOBUFS;
125
126 oi_size = i_size_read(file_inode(file));
127 if (oi_size == ni_size)
128 return 0;
129
130 inode_lock(file_inode(file));
131
132 /* if there's an extension to a partial page at the end of the backing
133 * file, we need to discard the partial page so that we pick up new
134 * data after it */
135 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
136 _debug("discard tail %llx", oi_size);
137 newattrs.ia_valid = ATTR_SIZE;
138 newattrs.ia_size = oi_size & PAGE_MASK;
139 ret = cachefiles_inject_remove_error();
140 if (ret == 0)
141 ret = notify_change(&init_user_ns, file->f_path.dentry,
142 &newattrs, NULL);
143 if (ret < 0)
144 goto truncate_failed;
145 }
146
147 newattrs.ia_valid = ATTR_SIZE;
148 newattrs.ia_size = ni_size;
149 ret = cachefiles_inject_write_error();
150 if (ret == 0)
151 ret = notify_change(&init_user_ns, file->f_path.dentry,
152 &newattrs, NULL);
153
154truncate_failed:
155 inode_unlock(file_inode(file));
156
157 if (ret < 0)
158 trace_cachefiles_io_error(NULL, file_inode(file), ret,
159 cachefiles_trace_notify_change_error);
160 if (ret == -EIO) {
161 cachefiles_io_error_obj(object, "Size set failed");
162 ret = -ENOBUFS;
163 }
164
165 _leave(" = %d", ret);
166 return ret;
167}
168
169/*
170 * Attempt to look up the nominated node in this cache
171 */
172static bool cachefiles_lookup_cookie(struct fscache_cookie *cookie)
173{
174 struct cachefiles_object *object;
175 struct cachefiles_cache *cache = cookie->volume->cache->cache_priv;
176 const struct cred *saved_cred;
177 bool success;
178
179 object = cachefiles_alloc_object(cookie);
180 if (!object)
181 goto fail;
182
183 _enter("{OBJ%x}", object->debug_id);
184
185 if (!cachefiles_cook_key(object))
186 goto fail_put;
187
188 cookie->cache_priv = object;
189
190 cachefiles_begin_secure(cache, &saved_cred);
191
192 success = cachefiles_look_up_object(object);
193 if (!success)
194 goto fail_withdraw;
195
196 cachefiles_see_object(object, cachefiles_obj_see_lookup_cookie);
197
198 spin_lock(&cache->object_list_lock);
199 list_add(&object->cache_link, &cache->object_list);
200 spin_unlock(&cache->object_list_lock);
201 cachefiles_adjust_size(object);
202
203 cachefiles_end_secure(cache, saved_cred);
204 _leave(" = t");
205 return true;
206
207fail_withdraw:
208 cachefiles_end_secure(cache, saved_cred);
209 cachefiles_see_object(object, cachefiles_obj_see_lookup_failed);
210 fscache_caching_failed(cookie);
211 _debug("failed c=%08x o=%08x", cookie->debug_id, object->debug_id);
212 /* The caller holds an access count on the cookie, so we need them to
213 * drop it before we can withdraw the object.
214 */
215 return false;
216
217fail_put:
218 cachefiles_put_object(object, cachefiles_obj_put_alloc_fail);
219fail:
220 return false;
221}
222
223/*
224 * Shorten the backing object to discard any dirty data and free up
225 * any unused granules.
226 */
227static bool cachefiles_shorten_object(struct cachefiles_object *object,
228 struct file *file, loff_t new_size)
229{
230 struct cachefiles_cache *cache = object->volume->cache;
231 struct inode *inode = file_inode(file);
232 loff_t i_size, dio_size;
233 int ret;
234
235 dio_size = round_up(new_size, CACHEFILES_DIO_BLOCK_SIZE);
236 i_size = i_size_read(inode);
237
238 trace_cachefiles_trunc(object, inode, i_size, dio_size,
239 cachefiles_trunc_shrink);
240 ret = cachefiles_inject_remove_error();
241 if (ret == 0)
242 ret = vfs_truncate(&file->f_path, dio_size);
243 if (ret < 0) {
244 trace_cachefiles_io_error(object, file_inode(file), ret,
245 cachefiles_trace_trunc_error);
246 cachefiles_io_error_obj(object, "Trunc-to-size failed %d", ret);
247 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
248 return false;
249 }
250
251 if (new_size < dio_size) {
252 trace_cachefiles_trunc(object, inode, dio_size, new_size,
253 cachefiles_trunc_dio_adjust);
254 ret = cachefiles_inject_write_error();
255 if (ret == 0)
256 ret = vfs_fallocate(file, FALLOC_FL_ZERO_RANGE,
257 new_size, dio_size - new_size);
258 if (ret < 0) {
259 trace_cachefiles_io_error(object, file_inode(file), ret,
260 cachefiles_trace_fallocate_error);
261 cachefiles_io_error_obj(object, "Trunc-to-dio-size failed %d", ret);
262 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
263 return false;
264 }
265 }
266
267 return true;
268}
269
270/*
271 * Resize the backing object.
272 */
273static void cachefiles_resize_cookie(struct netfs_cache_resources *cres,
274 loff_t new_size)
275{
276 struct cachefiles_object *object = cachefiles_cres_object(cres);
277 struct cachefiles_cache *cache = object->volume->cache;
278 struct fscache_cookie *cookie = object->cookie;
279 const struct cred *saved_cred;
280 struct file *file = cachefiles_cres_file(cres);
281 loff_t old_size = cookie->object_size;
282
283 _enter("%llu->%llu", old_size, new_size);
284
285 if (new_size < old_size) {
286 cachefiles_begin_secure(cache, &saved_cred);
287 cachefiles_shorten_object(object, file, new_size);
288 cachefiles_end_secure(cache, saved_cred);
289 object->cookie->object_size = new_size;
290 return;
291 }
292
293 /* The file is being expanded. We don't need to do anything
294 * particularly. cookie->initial_size doesn't change and so the point
295 * at which we have to download before doesn't change.
296 */
297 cookie->object_size = new_size;
298}
299
300/*
301 * Commit changes to the object as we drop it.
302 */
303static void cachefiles_commit_object(struct cachefiles_object *object,
304 struct cachefiles_cache *cache)
305{
306 bool update = false;
307
308 if (test_and_clear_bit(FSCACHE_COOKIE_LOCAL_WRITE, &object->cookie->flags))
309 update = true;
310 if (test_and_clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags))
311 update = true;
312 if (update)
313 cachefiles_set_object_xattr(object);
314
315 if (test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags))
316 cachefiles_commit_tmpfile(cache, object);
317}
318
319/*
320 * Finalise and object and close the VFS structs that we have.
321 */
322static void cachefiles_clean_up_object(struct cachefiles_object *object,
323 struct cachefiles_cache *cache)
324{
325 if (test_bit(FSCACHE_COOKIE_RETIRED, &object->cookie->flags)) {
326 if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
327 cachefiles_see_object(object, cachefiles_obj_see_clean_delete);
328 _debug("- inval object OBJ%x", object->debug_id);
329 cachefiles_delete_object(object, FSCACHE_OBJECT_WAS_RETIRED);
330 } else {
331 cachefiles_see_object(object, cachefiles_obj_see_clean_drop_tmp);
332 _debug("- inval object OBJ%x tmpfile", object->debug_id);
333 }
334 } else {
335 cachefiles_see_object(object, cachefiles_obj_see_clean_commit);
336 cachefiles_commit_object(object, cache);
337 }
338
339 cachefiles_unmark_inode_in_use(object, object->file);
340 if (object->file) {
341 fput(object->file);
342 object->file = NULL;
343 }
344}
345
346/*
347 * Withdraw caching for a cookie.
348 */
349static void cachefiles_withdraw_cookie(struct fscache_cookie *cookie)
350{
351 struct cachefiles_object *object = cookie->cache_priv;
352 struct cachefiles_cache *cache = object->volume->cache;
353 const struct cred *saved_cred;
354
355 _enter("o=%x", object->debug_id);
356 cachefiles_see_object(object, cachefiles_obj_see_withdraw_cookie);
357
358 if (!list_empty(&object->cache_link)) {
359 spin_lock(&cache->object_list_lock);
360 cachefiles_see_object(object, cachefiles_obj_see_withdrawal);
361 list_del_init(&object->cache_link);
362 spin_unlock(&cache->object_list_lock);
363 }
364
365 cachefiles_ondemand_clean_object(object);
366
367 if (object->file) {
368 cachefiles_begin_secure(cache, &saved_cred);
369 cachefiles_clean_up_object(object, cache);
370 cachefiles_end_secure(cache, saved_cred);
371 }
372
373 cookie->cache_priv = NULL;
374 cachefiles_put_object(object, cachefiles_obj_put_detach);
375}
376
377/*
378 * Invalidate the storage associated with a cookie.
379 */
380static bool cachefiles_invalidate_cookie(struct fscache_cookie *cookie)
381{
382 struct cachefiles_object *object = cookie->cache_priv;
383 struct file *new_file, *old_file;
384 bool old_tmpfile;
385
386 _enter("o=%x,[%llu]", object->debug_id, object->cookie->object_size);
387
388 old_tmpfile = test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
389
390 if (!object->file) {
391 fscache_resume_after_invalidation(cookie);
392 _leave(" = t [light]");
393 return true;
394 }
395
396 new_file = cachefiles_create_tmpfile(object);
397 if (IS_ERR(new_file))
398 goto failed;
399
400 /* Substitute the VFS target */
401 _debug("sub");
402 spin_lock(&object->lock);
403
404 old_file = object->file;
405 object->file = new_file;
406 object->content_info = CACHEFILES_CONTENT_NO_DATA;
407 set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
408 set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
409
410 spin_unlock(&object->lock);
411 _debug("subbed");
412
413 /* Allow I/O to take place again */
414 fscache_resume_after_invalidation(cookie);
415
416 if (old_file) {
417 if (!old_tmpfile) {
418 struct cachefiles_volume *volume = object->volume;
419 struct dentry *fan = volume->fanout[(u8)cookie->key_hash];
420
421 inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
422 cachefiles_bury_object(volume->cache, object, fan,
423 old_file->f_path.dentry,
424 FSCACHE_OBJECT_INVALIDATED);
425 }
426 fput(old_file);
427 }
428
429 _leave(" = t");
430 return true;
431
432failed:
433 _leave(" = f");
434 return false;
435}
436
437const struct fscache_cache_ops cachefiles_cache_ops = {
438 .name = "cachefiles",
439 .acquire_volume = cachefiles_acquire_volume,
440 .free_volume = cachefiles_free_volume,
441 .lookup_cookie = cachefiles_lookup_cookie,
442 .withdraw_cookie = cachefiles_withdraw_cookie,
443 .invalidate_cookie = cachefiles_invalidate_cookie,
444 .begin_operation = cachefiles_begin_operation,
445 .resize_cookie = cachefiles_resize_cookie,
446 .prepare_to_write = cachefiles_prepare_to_write,
447};