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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 "internal.h"
15
16struct cachefiles_lookup_data {
17 struct cachefiles_xattr *auxdata; /* auxiliary data */
18 char *key; /* key path */
19};
20
21static 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 */
26static 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, *p;
36 char *key;
37
38 cache = container_of(_cache, struct cachefiles_cache, cache);
39
40 _enter("{%s},%p,", cache->cache.identifier, cookie);
41
42 lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp);
43 if (!lookup_data)
44 goto nomem_lookup_data;
45
46 /* create a new object record and a temporary leaf image */
47 object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp);
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 */
64 buffer = kmalloc((2 + 512) + 3, cachefiles_gfp);
65 if (!buffer)
66 goto nomem_buffer;
67
68 keylen = cookie->key_len;
69 if (keylen <= sizeof(cookie->inline_key))
70 p = cookie->inline_key;
71 else
72 p = cookie->key;
73 memcpy(buffer + 2, p, keylen);
74
75 *(uint16_t *)buffer = keylen;
76 ((char *)buffer)[keylen + 2] = 0;
77 ((char *)buffer)[keylen + 3] = 0;
78 ((char *)buffer)[keylen + 4] = 0;
79
80 /* turn the raw key into something that can work with as a filename */
81 key = cachefiles_cook_key(buffer, keylen + 2, object->type);
82 if (!key)
83 goto nomem_key;
84
85 /* get hold of the auxiliary data and prepend the object type */
86 auxdata = buffer;
87 auxlen = cookie->aux_len;
88 if (auxlen) {
89 if (auxlen <= sizeof(cookie->inline_aux))
90 p = cookie->inline_aux;
91 else
92 p = cookie->aux;
93 memcpy(auxdata->data, p, auxlen);
94 }
95
96 auxdata->len = auxlen + 1;
97 auxdata->type = cookie->type;
98
99 lookup_data->auxdata = auxdata;
100 lookup_data->key = key;
101 object->lookup_data = lookup_data;
102
103 _leave(" = %p [%p]", &object->fscache, lookup_data);
104 return &object->fscache;
105
106nomem_key:
107 kfree(buffer);
108nomem_buffer:
109 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
110 kmem_cache_free(cachefiles_object_jar, object);
111 fscache_object_destroyed(&cache->cache);
112nomem_object:
113 kfree(lookup_data);
114nomem_lookup_data:
115 _leave(" = -ENOMEM");
116 return ERR_PTR(-ENOMEM);
117}
118
119/*
120 * attempt to look up the nominated node in this cache
121 * - return -ETIMEDOUT to be scheduled again
122 */
123static int cachefiles_lookup_object(struct fscache_object *_object)
124{
125 struct cachefiles_lookup_data *lookup_data;
126 struct cachefiles_object *parent, *object;
127 struct cachefiles_cache *cache;
128 const struct cred *saved_cred;
129 int ret;
130
131 _enter("{OBJ%x}", _object->debug_id);
132
133 cache = container_of(_object->cache, struct cachefiles_cache, cache);
134 parent = container_of(_object->parent,
135 struct cachefiles_object, fscache);
136 object = container_of(_object, struct cachefiles_object, fscache);
137 lookup_data = object->lookup_data;
138
139 ASSERTCMP(lookup_data, !=, NULL);
140
141 /* look up the key, creating any missing bits */
142 cachefiles_begin_secure(cache, &saved_cred);
143 ret = cachefiles_walk_to_object(parent, object,
144 lookup_data->key,
145 lookup_data->auxdata);
146 cachefiles_end_secure(cache, saved_cred);
147
148 /* polish off by setting the attributes of non-index files */
149 if (ret == 0 &&
150 object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
151 cachefiles_attr_changed(&object->fscache);
152
153 if (ret < 0 && ret != -ETIMEDOUT) {
154 if (ret != -ENOBUFS)
155 pr_warn("Lookup failed error %d\n", ret);
156 fscache_object_lookup_error(&object->fscache);
157 }
158
159 _leave(" [%d]", ret);
160 return ret;
161}
162
163/*
164 * indication of lookup completion
165 */
166static void cachefiles_lookup_complete(struct fscache_object *_object)
167{
168 struct cachefiles_object *object;
169
170 object = container_of(_object, struct cachefiles_object, fscache);
171
172 _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
173
174 if (object->lookup_data) {
175 kfree(object->lookup_data->key);
176 kfree(object->lookup_data->auxdata);
177 kfree(object->lookup_data);
178 object->lookup_data = NULL;
179 }
180}
181
182/*
183 * increment the usage count on an inode object (may fail if unmounting)
184 */
185static
186struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
187 enum fscache_obj_ref_trace why)
188{
189 struct cachefiles_object *object =
190 container_of(_object, struct cachefiles_object, fscache);
191 int u;
192
193 _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
194
195#ifdef CACHEFILES_DEBUG_SLAB
196 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
197#endif
198
199 u = atomic_inc_return(&object->usage);
200 trace_cachefiles_ref(object, _object->cookie,
201 (enum cachefiles_obj_ref_trace)why, u);
202 return &object->fscache;
203}
204
205/*
206 * update the auxiliary data for an object object on disk
207 */
208static void cachefiles_update_object(struct fscache_object *_object)
209{
210 struct cachefiles_object *object;
211 struct cachefiles_xattr *auxdata;
212 struct cachefiles_cache *cache;
213 struct fscache_cookie *cookie;
214 const struct cred *saved_cred;
215 const void *aux;
216 unsigned auxlen;
217
218 _enter("{OBJ%x}", _object->debug_id);
219
220 object = container_of(_object, struct cachefiles_object, fscache);
221 cache = container_of(object->fscache.cache, struct cachefiles_cache,
222 cache);
223
224 if (!fscache_use_cookie(_object)) {
225 _leave(" [relinq]");
226 return;
227 }
228
229 cookie = object->fscache.cookie;
230 auxlen = cookie->aux_len;
231
232 if (!auxlen) {
233 fscache_unuse_cookie(_object);
234 _leave(" [no aux]");
235 return;
236 }
237
238 auxdata = kmalloc(2 + auxlen + 3, cachefiles_gfp);
239 if (!auxdata) {
240 fscache_unuse_cookie(_object);
241 _leave(" [nomem]");
242 return;
243 }
244
245 aux = (auxlen <= sizeof(cookie->inline_aux)) ?
246 cookie->inline_aux : cookie->aux;
247
248 memcpy(auxdata->data, aux, auxlen);
249 fscache_unuse_cookie(_object);
250
251 auxdata->len = auxlen + 1;
252 auxdata->type = cookie->type;
253
254 cachefiles_begin_secure(cache, &saved_cred);
255 cachefiles_update_object_xattr(object, auxdata);
256 cachefiles_end_secure(cache, saved_cred);
257 kfree(auxdata);
258 _leave("");
259}
260
261/*
262 * discard the resources pinned by an object and effect retirement if
263 * requested
264 */
265static void cachefiles_drop_object(struct fscache_object *_object)
266{
267 struct cachefiles_object *object;
268 struct cachefiles_cache *cache;
269 const struct cred *saved_cred;
270 struct inode *inode;
271 blkcnt_t i_blocks = 0;
272
273 ASSERT(_object);
274
275 object = container_of(_object, struct cachefiles_object, fscache);
276
277 _enter("{OBJ%x,%d}",
278 object->fscache.debug_id, atomic_read(&object->usage));
279
280 cache = container_of(object->fscache.cache,
281 struct cachefiles_cache, cache);
282
283#ifdef CACHEFILES_DEBUG_SLAB
284 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
285#endif
286
287 /* We need to tidy the object up if we did in fact manage to open it.
288 * It's possible for us to get here before the object is fully
289 * initialised if the parent goes away or the object gets retired
290 * before we set it up.
291 */
292 if (object->dentry) {
293 /* delete retired objects */
294 if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
295 _object != cache->cache.fsdef
296 ) {
297 _debug("- retire object OBJ%x", object->fscache.debug_id);
298 inode = d_backing_inode(object->dentry);
299 if (inode)
300 i_blocks = inode->i_blocks;
301
302 cachefiles_begin_secure(cache, &saved_cred);
303 cachefiles_delete_object(cache, object);
304 cachefiles_end_secure(cache, saved_cred);
305 }
306
307 /* close the filesystem stuff attached to the object */
308 if (object->backer != object->dentry)
309 dput(object->backer);
310 object->backer = NULL;
311 }
312
313 /* note that the object is now inactive */
314 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
315 cachefiles_mark_object_inactive(cache, object, i_blocks);
316
317 dput(object->dentry);
318 object->dentry = NULL;
319
320 _leave("");
321}
322
323/*
324 * dispose of a reference to an object
325 */
326static void cachefiles_put_object(struct fscache_object *_object,
327 enum fscache_obj_ref_trace why)
328{
329 struct cachefiles_object *object;
330 struct fscache_cache *cache;
331 int u;
332
333 ASSERT(_object);
334
335 object = container_of(_object, struct cachefiles_object, fscache);
336
337 _enter("{OBJ%x,%d}",
338 object->fscache.debug_id, atomic_read(&object->usage));
339
340#ifdef CACHEFILES_DEBUG_SLAB
341 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
342#endif
343
344 ASSERTIFCMP(object->fscache.parent,
345 object->fscache.parent->n_children, >, 0);
346
347 u = atomic_dec_return(&object->usage);
348 trace_cachefiles_ref(object, _object->cookie,
349 (enum cachefiles_obj_ref_trace)why, u);
350 ASSERTCMP(u, !=, -1);
351 if (u == 0) {
352 _debug("- kill object OBJ%x", object->fscache.debug_id);
353
354 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
355 ASSERTCMP(object->fscache.parent, ==, NULL);
356 ASSERTCMP(object->backer, ==, NULL);
357 ASSERTCMP(object->dentry, ==, NULL);
358 ASSERTCMP(object->fscache.n_ops, ==, 0);
359 ASSERTCMP(object->fscache.n_children, ==, 0);
360
361 if (object->lookup_data) {
362 kfree(object->lookup_data->key);
363 kfree(object->lookup_data->auxdata);
364 kfree(object->lookup_data);
365 object->lookup_data = NULL;
366 }
367
368 cache = object->fscache.cache;
369 fscache_object_destroy(&object->fscache);
370 kmem_cache_free(cachefiles_object_jar, object);
371 fscache_object_destroyed(cache);
372 }
373
374 _leave("");
375}
376
377/*
378 * sync a cache
379 */
380static void cachefiles_sync_cache(struct fscache_cache *_cache)
381{
382 struct cachefiles_cache *cache;
383 const struct cred *saved_cred;
384 int ret;
385
386 _enter("%p", _cache);
387
388 cache = container_of(_cache, struct cachefiles_cache, cache);
389
390 /* make sure all pages pinned by operations on behalf of the netfs are
391 * written to disc */
392 cachefiles_begin_secure(cache, &saved_cred);
393 down_read(&cache->mnt->mnt_sb->s_umount);
394 ret = sync_filesystem(cache->mnt->mnt_sb);
395 up_read(&cache->mnt->mnt_sb->s_umount);
396 cachefiles_end_secure(cache, saved_cred);
397
398 if (ret == -EIO)
399 cachefiles_io_error(cache,
400 "Attempt to sync backing fs superblock"
401 " returned error %d",
402 ret);
403}
404
405/*
406 * check if the backing cache is updated to FS-Cache
407 * - called by FS-Cache when evaluates if need to invalidate the cache
408 */
409static int cachefiles_check_consistency(struct fscache_operation *op)
410{
411 struct cachefiles_object *object;
412 struct cachefiles_cache *cache;
413 const struct cred *saved_cred;
414 int ret;
415
416 _enter("{OBJ%x}", op->object->debug_id);
417
418 object = container_of(op->object, struct cachefiles_object, fscache);
419 cache = container_of(object->fscache.cache,
420 struct cachefiles_cache, cache);
421
422 cachefiles_begin_secure(cache, &saved_cred);
423 ret = cachefiles_check_auxdata(object);
424 cachefiles_end_secure(cache, saved_cred);
425
426 _leave(" = %d", ret);
427 return ret;
428}
429
430/*
431 * notification the attributes on an object have changed
432 * - called with reads/writes excluded by FS-Cache
433 */
434static int cachefiles_attr_changed(struct fscache_object *_object)
435{
436 struct cachefiles_object *object;
437 struct cachefiles_cache *cache;
438 const struct cred *saved_cred;
439 struct iattr newattrs;
440 uint64_t ni_size;
441 loff_t oi_size;
442 int ret;
443
444 ni_size = _object->store_limit_l;
445
446 _enter("{OBJ%x},[%llu]",
447 _object->debug_id, (unsigned long long) ni_size);
448
449 object = container_of(_object, struct cachefiles_object, fscache);
450 cache = container_of(object->fscache.cache,
451 struct cachefiles_cache, cache);
452
453 if (ni_size == object->i_size)
454 return 0;
455
456 if (!object->backer)
457 return -ENOBUFS;
458
459 ASSERT(d_is_reg(object->backer));
460
461 fscache_set_store_limit(&object->fscache, ni_size);
462
463 oi_size = i_size_read(d_backing_inode(object->backer));
464 if (oi_size == ni_size)
465 return 0;
466
467 cachefiles_begin_secure(cache, &saved_cred);
468 inode_lock(d_inode(object->backer));
469
470 /* if there's an extension to a partial page at the end of the backing
471 * file, we need to discard the partial page so that we pick up new
472 * data after it */
473 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
474 _debug("discard tail %llx", oi_size);
475 newattrs.ia_valid = ATTR_SIZE;
476 newattrs.ia_size = oi_size & PAGE_MASK;
477 ret = notify_change(object->backer, &newattrs, NULL);
478 if (ret < 0)
479 goto truncate_failed;
480 }
481
482 newattrs.ia_valid = ATTR_SIZE;
483 newattrs.ia_size = ni_size;
484 ret = notify_change(object->backer, &newattrs, NULL);
485
486truncate_failed:
487 inode_unlock(d_inode(object->backer));
488 cachefiles_end_secure(cache, saved_cred);
489
490 if (ret == -EIO) {
491 fscache_set_store_limit(&object->fscache, 0);
492 cachefiles_io_error_obj(object, "Size set failed");
493 ret = -ENOBUFS;
494 }
495
496 _leave(" = %d", ret);
497 return ret;
498}
499
500/*
501 * Invalidate an object
502 */
503static void cachefiles_invalidate_object(struct fscache_operation *op)
504{
505 struct cachefiles_object *object;
506 struct cachefiles_cache *cache;
507 const struct cred *saved_cred;
508 struct path path;
509 uint64_t ni_size;
510 int ret;
511
512 object = container_of(op->object, struct cachefiles_object, fscache);
513 cache = container_of(object->fscache.cache,
514 struct cachefiles_cache, cache);
515
516 ni_size = op->object->store_limit_l;
517
518 _enter("{OBJ%x},[%llu]",
519 op->object->debug_id, (unsigned long long)ni_size);
520
521 if (object->backer) {
522 ASSERT(d_is_reg(object->backer));
523
524 fscache_set_store_limit(&object->fscache, ni_size);
525
526 path.dentry = object->backer;
527 path.mnt = cache->mnt;
528
529 cachefiles_begin_secure(cache, &saved_cred);
530 ret = vfs_truncate(&path, 0);
531 if (ret == 0)
532 ret = vfs_truncate(&path, ni_size);
533 cachefiles_end_secure(cache, saved_cred);
534
535 if (ret != 0) {
536 fscache_set_store_limit(&object->fscache, 0);
537 if (ret == -EIO)
538 cachefiles_io_error_obj(object,
539 "Invalidate failed");
540 }
541 }
542
543 fscache_op_complete(op, true);
544 _leave("");
545}
546
547/*
548 * dissociate a cache from all the pages it was backing
549 */
550static void cachefiles_dissociate_pages(struct fscache_cache *cache)
551{
552 _enter("");
553}
554
555const struct fscache_cache_ops cachefiles_cache_ops = {
556 .name = "cachefiles",
557 .alloc_object = cachefiles_alloc_object,
558 .lookup_object = cachefiles_lookup_object,
559 .lookup_complete = cachefiles_lookup_complete,
560 .grab_object = cachefiles_grab_object,
561 .update_object = cachefiles_update_object,
562 .invalidate_object = cachefiles_invalidate_object,
563 .drop_object = cachefiles_drop_object,
564 .put_object = cachefiles_put_object,
565 .sync_cache = cachefiles_sync_cache,
566 .attr_changed = cachefiles_attr_changed,
567 .read_or_alloc_page = cachefiles_read_or_alloc_page,
568 .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
569 .allocate_page = cachefiles_allocate_page,
570 .allocate_pages = cachefiles_allocate_pages,
571 .write_page = cachefiles_write_page,
572 .uncache_page = cachefiles_uncache_page,
573 .dissociate_pages = cachefiles_dissociate_pages,
574 .check_consistency = cachefiles_check_consistency,
575};
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};