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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 if (cachefiles_ondemand_init_obj_info(object, volume)) {
35 kmem_cache_free(cachefiles_object_jar, object);
36 return NULL;
37 }
38
39 refcount_set(&object->ref, 1);
40
41 spin_lock_init(&object->lock);
42 INIT_LIST_HEAD(&object->cache_link);
43 object->volume = volume;
44 object->debug_id = atomic_inc_return(&cachefiles_object_debug_id);
45 object->cookie = fscache_get_cookie(cookie, fscache_cookie_get_attach_object);
46
47 fscache_count_object(vcookie->cache);
48 trace_cachefiles_ref(object->debug_id, cookie->debug_id, 1,
49 cachefiles_obj_new);
50 return object;
51}
52
53/*
54 * Note that an object has been seen.
55 */
56void cachefiles_see_object(struct cachefiles_object *object,
57 enum cachefiles_obj_ref_trace why)
58{
59 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id,
60 refcount_read(&object->ref), why);
61}
62
63/*
64 * Increment the usage count on an object;
65 */
66struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
67 enum cachefiles_obj_ref_trace why)
68{
69 int r;
70
71 __refcount_inc(&object->ref, &r);
72 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id, r, why);
73 return object;
74}
75
76/*
77 * dispose of a reference to an object
78 */
79void cachefiles_put_object(struct cachefiles_object *object,
80 enum cachefiles_obj_ref_trace why)
81{
82 unsigned int object_debug_id = object->debug_id;
83 unsigned int cookie_debug_id = object->cookie->debug_id;
84 struct fscache_cache *cache;
85 bool done;
86 int r;
87
88 done = __refcount_dec_and_test(&object->ref, &r);
89 trace_cachefiles_ref(object_debug_id, cookie_debug_id, r, why);
90 if (done) {
91 _debug("- kill object OBJ%x", object_debug_id);
92
93 ASSERTCMP(object->file, ==, NULL);
94
95 kfree(object->d_name);
96 cachefiles_ondemand_deinit_obj_info(object);
97 cache = object->volume->cache->cache;
98 fscache_put_cookie(object->cookie, fscache_cookie_put_object);
99 object->cookie = NULL;
100 kmem_cache_free(cachefiles_object_jar, object);
101 fscache_uncount_object(cache);
102 }
103
104 _leave("");
105}
106
107/*
108 * Adjust the size of a cache file if necessary to match the DIO size. We keep
109 * the EOF marker a multiple of DIO blocks so that we don't fall back to doing
110 * non-DIO for a partial block straddling the EOF, but we also have to be
111 * careful of someone expanding the file and accidentally accreting the
112 * padding.
113 */
114static int cachefiles_adjust_size(struct cachefiles_object *object)
115{
116 struct iattr newattrs;
117 struct file *file = object->file;
118 uint64_t ni_size;
119 loff_t oi_size;
120 int ret;
121
122 ni_size = object->cookie->object_size;
123 ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
124
125 _enter("{OBJ%x},[%llu]",
126 object->debug_id, (unsigned long long) ni_size);
127
128 if (!file)
129 return -ENOBUFS;
130
131 oi_size = i_size_read(file_inode(file));
132 if (oi_size == ni_size)
133 return 0;
134
135 inode_lock(file_inode(file));
136
137 /* if there's an extension to a partial page at the end of the backing
138 * file, we need to discard the partial page so that we pick up new
139 * data after it */
140 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
141 _debug("discard tail %llx", oi_size);
142 newattrs.ia_valid = ATTR_SIZE;
143 newattrs.ia_size = oi_size & PAGE_MASK;
144 ret = cachefiles_inject_remove_error();
145 if (ret == 0)
146 ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
147 &newattrs, NULL);
148 if (ret < 0)
149 goto truncate_failed;
150 }
151
152 newattrs.ia_valid = ATTR_SIZE;
153 newattrs.ia_size = ni_size;
154 ret = cachefiles_inject_write_error();
155 if (ret == 0)
156 ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
157 &newattrs, NULL);
158
159truncate_failed:
160 inode_unlock(file_inode(file));
161
162 if (ret < 0)
163 trace_cachefiles_io_error(NULL, file_inode(file), ret,
164 cachefiles_trace_notify_change_error);
165 if (ret == -EIO) {
166 cachefiles_io_error_obj(object, "Size set failed");
167 ret = -ENOBUFS;
168 }
169
170 _leave(" = %d", ret);
171 return ret;
172}
173
174/*
175 * Attempt to look up the nominated node in this cache
176 */
177static bool cachefiles_lookup_cookie(struct fscache_cookie *cookie)
178{
179 struct cachefiles_object *object;
180 struct cachefiles_cache *cache = cookie->volume->cache->cache_priv;
181 const struct cred *saved_cred;
182 bool success;
183
184 object = cachefiles_alloc_object(cookie);
185 if (!object)
186 goto fail;
187
188 _enter("{OBJ%x}", object->debug_id);
189
190 if (!cachefiles_cook_key(object))
191 goto fail_put;
192
193 cookie->cache_priv = object;
194
195 cachefiles_begin_secure(cache, &saved_cred);
196
197 success = cachefiles_look_up_object(object);
198 if (!success)
199 goto fail_withdraw;
200
201 cachefiles_see_object(object, cachefiles_obj_see_lookup_cookie);
202
203 spin_lock(&cache->object_list_lock);
204 list_add(&object->cache_link, &cache->object_list);
205 spin_unlock(&cache->object_list_lock);
206 cachefiles_adjust_size(object);
207
208 cachefiles_end_secure(cache, saved_cred);
209 _leave(" = t");
210 return true;
211
212fail_withdraw:
213 cachefiles_end_secure(cache, saved_cred);
214 cachefiles_see_object(object, cachefiles_obj_see_lookup_failed);
215 fscache_caching_failed(cookie);
216 _debug("failed c=%08x o=%08x", cookie->debug_id, object->debug_id);
217 /* The caller holds an access count on the cookie, so we need them to
218 * drop it before we can withdraw the object.
219 */
220 return false;
221
222fail_put:
223 cachefiles_put_object(object, cachefiles_obj_put_alloc_fail);
224fail:
225 return false;
226}
227
228/*
229 * Shorten the backing object to discard any dirty data and free up
230 * any unused granules.
231 */
232static bool cachefiles_shorten_object(struct cachefiles_object *object,
233 struct file *file, loff_t new_size)
234{
235 struct cachefiles_cache *cache = object->volume->cache;
236 struct inode *inode = file_inode(file);
237 loff_t i_size, dio_size;
238 int ret;
239
240 dio_size = round_up(new_size, CACHEFILES_DIO_BLOCK_SIZE);
241 i_size = i_size_read(inode);
242
243 trace_cachefiles_trunc(object, inode, i_size, dio_size,
244 cachefiles_trunc_shrink);
245 ret = cachefiles_inject_remove_error();
246 if (ret == 0)
247 ret = vfs_truncate(&file->f_path, dio_size);
248 if (ret < 0) {
249 trace_cachefiles_io_error(object, file_inode(file), ret,
250 cachefiles_trace_trunc_error);
251 cachefiles_io_error_obj(object, "Trunc-to-size failed %d", ret);
252 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
253 return false;
254 }
255
256 if (new_size < dio_size) {
257 trace_cachefiles_trunc(object, inode, dio_size, new_size,
258 cachefiles_trunc_dio_adjust);
259 ret = cachefiles_inject_write_error();
260 if (ret == 0)
261 ret = vfs_fallocate(file, FALLOC_FL_ZERO_RANGE,
262 new_size, dio_size - new_size);
263 if (ret < 0) {
264 trace_cachefiles_io_error(object, file_inode(file), ret,
265 cachefiles_trace_fallocate_error);
266 cachefiles_io_error_obj(object, "Trunc-to-dio-size failed %d", ret);
267 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
268 return false;
269 }
270 }
271
272 return true;
273}
274
275/*
276 * Resize the backing object.
277 */
278static void cachefiles_resize_cookie(struct netfs_cache_resources *cres,
279 loff_t new_size)
280{
281 struct cachefiles_object *object = cachefiles_cres_object(cres);
282 struct cachefiles_cache *cache = object->volume->cache;
283 struct fscache_cookie *cookie = object->cookie;
284 const struct cred *saved_cred;
285 struct file *file = cachefiles_cres_file(cres);
286 loff_t old_size = cookie->object_size;
287
288 _enter("%llu->%llu", old_size, new_size);
289
290 if (new_size < old_size) {
291 cachefiles_begin_secure(cache, &saved_cred);
292 cachefiles_shorten_object(object, file, new_size);
293 cachefiles_end_secure(cache, saved_cred);
294 object->cookie->object_size = new_size;
295 return;
296 }
297
298 /* The file is being expanded. We don't need to do anything
299 * particularly. cookie->initial_size doesn't change and so the point
300 * at which we have to download before doesn't change.
301 */
302 cookie->object_size = new_size;
303}
304
305/*
306 * Commit changes to the object as we drop it.
307 */
308static void cachefiles_commit_object(struct cachefiles_object *object,
309 struct cachefiles_cache *cache)
310{
311 bool update = false;
312
313 if (test_and_clear_bit(FSCACHE_COOKIE_LOCAL_WRITE, &object->cookie->flags))
314 update = true;
315 if (test_and_clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags))
316 update = true;
317 if (update)
318 cachefiles_set_object_xattr(object);
319
320 if (test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags))
321 cachefiles_commit_tmpfile(cache, object);
322}
323
324/*
325 * Finalise and object and close the VFS structs that we have.
326 */
327static void cachefiles_clean_up_object(struct cachefiles_object *object,
328 struct cachefiles_cache *cache)
329{
330 struct file *file;
331
332 if (test_bit(FSCACHE_COOKIE_RETIRED, &object->cookie->flags)) {
333 if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
334 cachefiles_see_object(object, cachefiles_obj_see_clean_delete);
335 _debug("- inval object OBJ%x", object->debug_id);
336 cachefiles_delete_object(object, FSCACHE_OBJECT_WAS_RETIRED);
337 } else {
338 cachefiles_see_object(object, cachefiles_obj_see_clean_drop_tmp);
339 _debug("- inval object OBJ%x tmpfile", object->debug_id);
340 }
341 } else {
342 cachefiles_see_object(object, cachefiles_obj_see_clean_commit);
343 cachefiles_commit_object(object, cache);
344 }
345
346 cachefiles_unmark_inode_in_use(object, object->file);
347
348 spin_lock(&object->lock);
349 file = object->file;
350 object->file = NULL;
351 spin_unlock(&object->lock);
352
353 if (file)
354 fput(file);
355}
356
357/*
358 * Withdraw caching for a cookie.
359 */
360static void cachefiles_withdraw_cookie(struct fscache_cookie *cookie)
361{
362 struct cachefiles_object *object = cookie->cache_priv;
363 struct cachefiles_cache *cache = object->volume->cache;
364 const struct cred *saved_cred;
365
366 _enter("o=%x", object->debug_id);
367 cachefiles_see_object(object, cachefiles_obj_see_withdraw_cookie);
368
369 if (!list_empty(&object->cache_link)) {
370 spin_lock(&cache->object_list_lock);
371 cachefiles_see_object(object, cachefiles_obj_see_withdrawal);
372 list_del_init(&object->cache_link);
373 spin_unlock(&cache->object_list_lock);
374 }
375
376 cachefiles_ondemand_clean_object(object);
377
378 if (object->file) {
379 cachefiles_begin_secure(cache, &saved_cred);
380 cachefiles_clean_up_object(object, cache);
381 cachefiles_end_secure(cache, saved_cred);
382 }
383
384 cookie->cache_priv = NULL;
385 cachefiles_put_object(object, cachefiles_obj_put_detach);
386}
387
388/*
389 * Invalidate the storage associated with a cookie.
390 */
391static bool cachefiles_invalidate_cookie(struct fscache_cookie *cookie)
392{
393 struct cachefiles_object *object = cookie->cache_priv;
394 struct file *new_file, *old_file;
395 bool old_tmpfile;
396
397 _enter("o=%x,[%llu]", object->debug_id, object->cookie->object_size);
398
399 old_tmpfile = test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
400
401 if (!object->file) {
402 fscache_resume_after_invalidation(cookie);
403 _leave(" = t [light]");
404 return true;
405 }
406
407 new_file = cachefiles_create_tmpfile(object);
408 if (IS_ERR(new_file))
409 goto failed;
410
411 /* Substitute the VFS target */
412 _debug("sub");
413 spin_lock(&object->lock);
414
415 old_file = object->file;
416 object->file = new_file;
417 object->content_info = CACHEFILES_CONTENT_NO_DATA;
418 set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
419 set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
420
421 spin_unlock(&object->lock);
422 _debug("subbed");
423
424 /* Allow I/O to take place again */
425 fscache_resume_after_invalidation(cookie);
426
427 if (old_file) {
428 if (!old_tmpfile) {
429 struct cachefiles_volume *volume = object->volume;
430 struct dentry *fan = volume->fanout[(u8)cookie->key_hash];
431
432 inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
433 cachefiles_bury_object(volume->cache, object, fan,
434 old_file->f_path.dentry,
435 FSCACHE_OBJECT_INVALIDATED);
436 }
437 fput(old_file);
438 }
439
440 _leave(" = t");
441 return true;
442
443failed:
444 _leave(" = f");
445 return false;
446}
447
448const struct fscache_cache_ops cachefiles_cache_ops = {
449 .name = "cachefiles",
450 .acquire_volume = cachefiles_acquire_volume,
451 .free_volume = cachefiles_free_volume,
452 .lookup_cookie = cachefiles_lookup_cookie,
453 .withdraw_cookie = cachefiles_withdraw_cookie,
454 .invalidate_cookie = cachefiles_invalidate_cookie,
455 .begin_operation = cachefiles_begin_operation,
456 .resize_cookie = cachefiles_resize_cookie,
457 .prepare_to_write = cachefiles_prepare_to_write,
458};