1 // SPDX-License-Identifier: GPL-2.0-or-later
2 #include <linux/anon_inodes.h>
3 #include <linux/uio.h>
4 #include "internal.h"
5
6 struct ondemand_anon_file {
7 struct file *file;
8 int fd;
9 };
10
cachefiles_req_put(struct cachefiles_req * req)11 static inline void cachefiles_req_put(struct cachefiles_req *req)
12 {
13 if (refcount_dec_and_test(&req->ref))
14 kfree(req);
15 }
16
cachefiles_ondemand_fd_release(struct inode * inode,struct file * file)17 static int cachefiles_ondemand_fd_release(struct inode *inode,
18 struct file *file)
19 {
20 struct cachefiles_object *object = file->private_data;
21 struct cachefiles_cache *cache;
22 struct cachefiles_ondemand_info *info;
23 int object_id;
24 struct cachefiles_req *req;
25 XA_STATE(xas, NULL, 0);
26
27 if (!object)
28 return 0;
29
30 info = object->ondemand;
31 cache = object->volume->cache;
32 xas.xa = &cache->reqs;
33
34 xa_lock(&cache->reqs);
35 spin_lock(&info->lock);
36 object_id = info->ondemand_id;
37 info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED;
38 cachefiles_ondemand_set_object_close(object);
39 spin_unlock(&info->lock);
40
41 /* Only flush CACHEFILES_REQ_NEW marked req to avoid race with daemon_read */
42 xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
43 if (req->msg.object_id == object_id &&
44 req->msg.opcode == CACHEFILES_OP_CLOSE) {
45 complete(&req->done);
46 xas_store(&xas, NULL);
47 }
48 }
49 xa_unlock(&cache->reqs);
50
51 xa_erase(&cache->ondemand_ids, object_id);
52 trace_cachefiles_ondemand_fd_release(object, object_id);
53 cachefiles_put_object(object, cachefiles_obj_put_ondemand_fd);
54 cachefiles_put_unbind_pincount(cache);
55 return 0;
56 }
57
cachefiles_ondemand_fd_write_iter(struct kiocb * kiocb,struct iov_iter * iter)58 static ssize_t cachefiles_ondemand_fd_write_iter(struct kiocb *kiocb,
59 struct iov_iter *iter)
60 {
61 struct cachefiles_object *object = kiocb->ki_filp->private_data;
62 struct cachefiles_cache *cache = object->volume->cache;
63 struct file *file;
64 size_t len = iter->count, aligned_len = len;
65 loff_t pos = kiocb->ki_pos;
66 const struct cred *saved_cred;
67 int ret;
68
69 spin_lock(&object->lock);
70 file = object->file;
71 if (!file) {
72 spin_unlock(&object->lock);
73 return -ENOBUFS;
74 }
75 get_file(file);
76 spin_unlock(&object->lock);
77
78 cachefiles_begin_secure(cache, &saved_cred);
79 ret = __cachefiles_prepare_write(object, file, &pos, &aligned_len, len, true);
80 cachefiles_end_secure(cache, saved_cred);
81 if (ret < 0)
82 goto out;
83
84 trace_cachefiles_ondemand_fd_write(object, file_inode(file), pos, len);
85 ret = __cachefiles_write(object, file, pos, iter, NULL, NULL);
86 if (!ret) {
87 ret = len;
88 kiocb->ki_pos += ret;
89 }
90
91 out:
92 fput(file);
93 return ret;
94 }
95
cachefiles_ondemand_fd_llseek(struct file * filp,loff_t pos,int whence)96 static loff_t cachefiles_ondemand_fd_llseek(struct file *filp, loff_t pos,
97 int whence)
98 {
99 struct cachefiles_object *object = filp->private_data;
100 struct file *file;
101 loff_t ret;
102
103 spin_lock(&object->lock);
104 file = object->file;
105 if (!file) {
106 spin_unlock(&object->lock);
107 return -ENOBUFS;
108 }
109 get_file(file);
110 spin_unlock(&object->lock);
111
112 ret = vfs_llseek(file, pos, whence);
113 fput(file);
114
115 return ret;
116 }
117
cachefiles_ondemand_fd_ioctl(struct file * filp,unsigned int ioctl,unsigned long id)118 static long cachefiles_ondemand_fd_ioctl(struct file *filp, unsigned int ioctl,
119 unsigned long id)
120 {
121 struct cachefiles_object *object = filp->private_data;
122 struct cachefiles_cache *cache = object->volume->cache;
123 struct cachefiles_req *req;
124 XA_STATE(xas, &cache->reqs, id);
125
126 if (ioctl != CACHEFILES_IOC_READ_COMPLETE)
127 return -EINVAL;
128
129 if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
130 return -EOPNOTSUPP;
131
132 xa_lock(&cache->reqs);
133 req = xas_load(&xas);
134 if (!req || req->msg.opcode != CACHEFILES_OP_READ ||
135 req->object != object) {
136 xa_unlock(&cache->reqs);
137 return -EINVAL;
138 }
139 xas_store(&xas, NULL);
140 xa_unlock(&cache->reqs);
141
142 trace_cachefiles_ondemand_cread(object, id);
143 complete(&req->done);
144 return 0;
145 }
146
147 static const struct file_operations cachefiles_ondemand_fd_fops = {
148 .owner = THIS_MODULE,
149 .release = cachefiles_ondemand_fd_release,
150 .write_iter = cachefiles_ondemand_fd_write_iter,
151 .llseek = cachefiles_ondemand_fd_llseek,
152 .unlocked_ioctl = cachefiles_ondemand_fd_ioctl,
153 };
154
155 /*
156 * OPEN request Completion (copen)
157 * - command: "copen <id>,<cache_size>"
158 * <cache_size> indicates the object size if >=0, error code if negative
159 */
cachefiles_ondemand_copen(struct cachefiles_cache * cache,char * args)160 int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args)
161 {
162 struct cachefiles_req *req;
163 struct fscache_cookie *cookie;
164 struct cachefiles_ondemand_info *info;
165 char *pid, *psize;
166 unsigned long id;
167 long size;
168 int ret;
169 XA_STATE(xas, &cache->reqs, 0);
170
171 if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
172 return -EOPNOTSUPP;
173
174 if (!*args) {
175 pr_err("Empty id specified\n");
176 return -EINVAL;
177 }
178
179 pid = args;
180 psize = strchr(args, ',');
181 if (!psize) {
182 pr_err("Cache size is not specified\n");
183 return -EINVAL;
184 }
185
186 *psize = 0;
187 psize++;
188
189 ret = kstrtoul(pid, 0, &id);
190 if (ret)
191 return ret;
192
193 xa_lock(&cache->reqs);
194 xas.xa_index = id;
195 req = xas_load(&xas);
196 if (!req || req->msg.opcode != CACHEFILES_OP_OPEN ||
197 !req->object->ondemand->ondemand_id) {
198 xa_unlock(&cache->reqs);
199 return -EINVAL;
200 }
201 xas_store(&xas, NULL);
202 xa_unlock(&cache->reqs);
203
204 info = req->object->ondemand;
205 /* fail OPEN request if copen format is invalid */
206 ret = kstrtol(psize, 0, &size);
207 if (ret) {
208 req->error = ret;
209 goto out;
210 }
211
212 /* fail OPEN request if daemon reports an error */
213 if (size < 0) {
214 if (!IS_ERR_VALUE(size)) {
215 req->error = -EINVAL;
216 ret = -EINVAL;
217 } else {
218 req->error = size;
219 ret = 0;
220 }
221 goto out;
222 }
223
224 spin_lock(&info->lock);
225 /*
226 * The anonymous fd was closed before copen ? Fail the request.
227 *
228 * t1 | t2
229 * ---------------------------------------------------------
230 * cachefiles_ondemand_copen
231 * req = xa_erase(&cache->reqs, id)
232 * // Anon fd is maliciously closed.
233 * cachefiles_ondemand_fd_release
234 * xa_lock(&cache->reqs)
235 * cachefiles_ondemand_set_object_close(object)
236 * xa_unlock(&cache->reqs)
237 * cachefiles_ondemand_set_object_open
238 * // No one will ever close it again.
239 * cachefiles_ondemand_daemon_read
240 * cachefiles_ondemand_select_req
241 *
242 * Get a read req but its fd is already closed. The daemon can't
243 * issue a cread ioctl with an closed fd, then hung.
244 */
245 if (info->ondemand_id == CACHEFILES_ONDEMAND_ID_CLOSED) {
246 spin_unlock(&info->lock);
247 req->error = -EBADFD;
248 goto out;
249 }
250 cookie = req->object->cookie;
251 cookie->object_size = size;
252 if (size)
253 clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
254 else
255 set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
256 trace_cachefiles_ondemand_copen(req->object, id, size);
257
258 cachefiles_ondemand_set_object_open(req->object);
259 spin_unlock(&info->lock);
260 wake_up_all(&cache->daemon_pollwq);
261
262 out:
263 spin_lock(&info->lock);
264 /* Need to set object close to avoid reopen status continuing */
265 if (info->ondemand_id == CACHEFILES_ONDEMAND_ID_CLOSED)
266 cachefiles_ondemand_set_object_close(req->object);
267 spin_unlock(&info->lock);
268 complete(&req->done);
269 return ret;
270 }
271
cachefiles_ondemand_restore(struct cachefiles_cache * cache,char * args)272 int cachefiles_ondemand_restore(struct cachefiles_cache *cache, char *args)
273 {
274 struct cachefiles_req *req;
275
276 XA_STATE(xas, &cache->reqs, 0);
277
278 if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
279 return -EOPNOTSUPP;
280
281 /*
282 * Reset the requests to CACHEFILES_REQ_NEW state, so that the
283 * requests have been processed halfway before the crash of the
284 * user daemon could be reprocessed after the recovery.
285 */
286 xas_lock(&xas);
287 xas_for_each(&xas, req, ULONG_MAX)
288 xas_set_mark(&xas, CACHEFILES_REQ_NEW);
289 xas_unlock(&xas);
290
291 wake_up_all(&cache->daemon_pollwq);
292 return 0;
293 }
294
cachefiles_ondemand_get_fd(struct cachefiles_req * req,struct ondemand_anon_file * anon_file)295 static int cachefiles_ondemand_get_fd(struct cachefiles_req *req,
296 struct ondemand_anon_file *anon_file)
297 {
298 struct cachefiles_object *object;
299 struct cachefiles_cache *cache;
300 struct cachefiles_open *load;
301 u32 object_id;
302 int ret;
303
304 object = cachefiles_grab_object(req->object,
305 cachefiles_obj_get_ondemand_fd);
306 cache = object->volume->cache;
307
308 ret = xa_alloc_cyclic(&cache->ondemand_ids, &object_id, NULL,
309 XA_LIMIT(1, INT_MAX),
310 &cache->ondemand_id_next, GFP_KERNEL);
311 if (ret < 0)
312 goto err;
313
314 anon_file->fd = get_unused_fd_flags(O_WRONLY);
315 if (anon_file->fd < 0) {
316 ret = anon_file->fd;
317 goto err_free_id;
318 }
319
320 anon_file->file = anon_inode_getfile_fmode("[cachefiles]",
321 &cachefiles_ondemand_fd_fops, object,
322 O_WRONLY, FMODE_PWRITE | FMODE_LSEEK);
323 if (IS_ERR(anon_file->file)) {
324 ret = PTR_ERR(anon_file->file);
325 goto err_put_fd;
326 }
327
328 spin_lock(&object->ondemand->lock);
329 if (object->ondemand->ondemand_id > 0) {
330 spin_unlock(&object->ondemand->lock);
331 /* Pair with check in cachefiles_ondemand_fd_release(). */
332 anon_file->file->private_data = NULL;
333 ret = -EEXIST;
334 goto err_put_file;
335 }
336
337 load = (void *)req->msg.data;
338 load->fd = anon_file->fd;
339 object->ondemand->ondemand_id = object_id;
340 spin_unlock(&object->ondemand->lock);
341
342 cachefiles_get_unbind_pincount(cache);
343 trace_cachefiles_ondemand_open(object, &req->msg, load);
344 return 0;
345
346 err_put_file:
347 fput(anon_file->file);
348 anon_file->file = NULL;
349 err_put_fd:
350 put_unused_fd(anon_file->fd);
351 anon_file->fd = ret;
352 err_free_id:
353 xa_erase(&cache->ondemand_ids, object_id);
354 err:
355 spin_lock(&object->ondemand->lock);
356 /* Avoid marking an opened object as closed. */
357 if (object->ondemand->ondemand_id <= 0)
358 cachefiles_ondemand_set_object_close(object);
359 spin_unlock(&object->ondemand->lock);
360 cachefiles_put_object(object, cachefiles_obj_put_ondemand_fd);
361 return ret;
362 }
363
ondemand_object_worker(struct work_struct * work)364 static void ondemand_object_worker(struct work_struct *work)
365 {
366 struct cachefiles_ondemand_info *info =
367 container_of(work, struct cachefiles_ondemand_info, ondemand_work);
368
369 cachefiles_ondemand_init_object(info->object);
370 }
371
372 /*
373 * If there are any inflight or subsequent READ requests on the
374 * closed object, reopen it.
375 * Skip read requests whose related object is reopening.
376 */
cachefiles_ondemand_select_req(struct xa_state * xas,unsigned long xa_max)377 static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xas,
378 unsigned long xa_max)
379 {
380 struct cachefiles_req *req;
381 struct cachefiles_object *object;
382 struct cachefiles_ondemand_info *info;
383
384 xas_for_each_marked(xas, req, xa_max, CACHEFILES_REQ_NEW) {
385 if (req->msg.opcode != CACHEFILES_OP_READ)
386 return req;
387 object = req->object;
388 info = object->ondemand;
389 if (cachefiles_ondemand_object_is_close(object)) {
390 cachefiles_ondemand_set_object_reopening(object);
391 queue_work(fscache_wq, &info->ondemand_work);
392 continue;
393 }
394 if (cachefiles_ondemand_object_is_reopening(object))
395 continue;
396 return req;
397 }
398 return NULL;
399 }
400
cachefiles_ondemand_finish_req(struct cachefiles_req * req,struct xa_state * xas,int err)401 static inline bool cachefiles_ondemand_finish_req(struct cachefiles_req *req,
402 struct xa_state *xas, int err)
403 {
404 if (unlikely(!xas || !req))
405 return false;
406
407 if (xa_cmpxchg(xas->xa, xas->xa_index, req, NULL, 0) != req)
408 return false;
409
410 req->error = err;
411 complete(&req->done);
412 return true;
413 }
414
cachefiles_ondemand_daemon_read(struct cachefiles_cache * cache,char __user * _buffer,size_t buflen)415 ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
416 char __user *_buffer, size_t buflen)
417 {
418 struct cachefiles_req *req;
419 struct cachefiles_msg *msg;
420 size_t n;
421 int ret = 0;
422 struct ondemand_anon_file anon_file;
423 XA_STATE(xas, &cache->reqs, cache->req_id_next);
424
425 xa_lock(&cache->reqs);
426 /*
427 * Cyclically search for a request that has not ever been processed,
428 * to prevent requests from being processed repeatedly, and make
429 * request distribution fair.
430 */
431 req = cachefiles_ondemand_select_req(&xas, ULONG_MAX);
432 if (!req && cache->req_id_next > 0) {
433 xas_set(&xas, 0);
434 req = cachefiles_ondemand_select_req(&xas, cache->req_id_next - 1);
435 }
436 if (!req) {
437 xa_unlock(&cache->reqs);
438 return 0;
439 }
440
441 msg = &req->msg;
442 n = msg->len;
443
444 if (n > buflen) {
445 xa_unlock(&cache->reqs);
446 return -EMSGSIZE;
447 }
448
449 xas_clear_mark(&xas, CACHEFILES_REQ_NEW);
450 cache->req_id_next = xas.xa_index + 1;
451 refcount_inc(&req->ref);
452 cachefiles_grab_object(req->object, cachefiles_obj_get_read_req);
453 xa_unlock(&cache->reqs);
454
455 if (msg->opcode == CACHEFILES_OP_OPEN) {
456 ret = cachefiles_ondemand_get_fd(req, &anon_file);
457 if (ret)
458 goto out;
459 }
460
461 msg->msg_id = xas.xa_index;
462 msg->object_id = req->object->ondemand->ondemand_id;
463
464 if (copy_to_user(_buffer, msg, n) != 0)
465 ret = -EFAULT;
466
467 if (msg->opcode == CACHEFILES_OP_OPEN) {
468 if (ret < 0) {
469 fput(anon_file.file);
470 put_unused_fd(anon_file.fd);
471 goto out;
472 }
473 fd_install(anon_file.fd, anon_file.file);
474 }
475 out:
476 cachefiles_put_object(req->object, cachefiles_obj_put_read_req);
477 /* Remove error request and CLOSE request has no reply */
478 if (ret || msg->opcode == CACHEFILES_OP_CLOSE)
479 cachefiles_ondemand_finish_req(req, &xas, ret);
480 cachefiles_req_put(req);
481 return ret ? ret : n;
482 }
483
484 typedef int (*init_req_fn)(struct cachefiles_req *req, void *private);
485
cachefiles_ondemand_send_req(struct cachefiles_object * object,enum cachefiles_opcode opcode,size_t data_len,init_req_fn init_req,void * private)486 static int cachefiles_ondemand_send_req(struct cachefiles_object *object,
487 enum cachefiles_opcode opcode,
488 size_t data_len,
489 init_req_fn init_req,
490 void *private)
491 {
492 struct cachefiles_cache *cache = object->volume->cache;
493 struct cachefiles_req *req = NULL;
494 XA_STATE(xas, &cache->reqs, 0);
495 int ret;
496
497 if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags))
498 return 0;
499
500 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
501 ret = -EIO;
502 goto out;
503 }
504
505 req = kzalloc(sizeof(*req) + data_len, GFP_KERNEL);
506 if (!req) {
507 ret = -ENOMEM;
508 goto out;
509 }
510
511 refcount_set(&req->ref, 1);
512 req->object = object;
513 init_completion(&req->done);
514 req->msg.opcode = opcode;
515 req->msg.len = sizeof(struct cachefiles_msg) + data_len;
516
517 ret = init_req(req, private);
518 if (ret)
519 goto out;
520
521 do {
522 /*
523 * Stop enqueuing the request when daemon is dying. The
524 * following two operations need to be atomic as a whole.
525 * 1) check cache state, and
526 * 2) enqueue request if cache is alive.
527 * Otherwise the request may be enqueued after xarray has been
528 * flushed, leaving the orphan request never being completed.
529 *
530 * CPU 1 CPU 2
531 * ===== =====
532 * test CACHEFILES_DEAD bit
533 * set CACHEFILES_DEAD bit
534 * flush requests in the xarray
535 * enqueue the request
536 */
537 xas_lock(&xas);
538
539 if (test_bit(CACHEFILES_DEAD, &cache->flags) ||
540 cachefiles_ondemand_object_is_dropping(object)) {
541 xas_unlock(&xas);
542 ret = -EIO;
543 goto out;
544 }
545
546 /* coupled with the barrier in cachefiles_flush_reqs() */
547 smp_mb();
548
549 if (opcode == CACHEFILES_OP_CLOSE &&
550 !cachefiles_ondemand_object_is_open(object)) {
551 WARN_ON_ONCE(object->ondemand->ondemand_id == 0);
552 xas_unlock(&xas);
553 ret = -EIO;
554 goto out;
555 }
556
557 /*
558 * Cyclically find a free xas to avoid msg_id reuse that would
559 * cause the daemon to successfully copen a stale msg_id.
560 */
561 xas.xa_index = cache->msg_id_next;
562 xas_find_marked(&xas, UINT_MAX, XA_FREE_MARK);
563 if (xas.xa_node == XAS_RESTART) {
564 xas.xa_index = 0;
565 xas_find_marked(&xas, cache->msg_id_next - 1, XA_FREE_MARK);
566 }
567 if (xas.xa_node == XAS_RESTART)
568 xas_set_err(&xas, -EBUSY);
569
570 xas_store(&xas, req);
571 if (xas_valid(&xas)) {
572 cache->msg_id_next = xas.xa_index + 1;
573 xas_clear_mark(&xas, XA_FREE_MARK);
574 xas_set_mark(&xas, CACHEFILES_REQ_NEW);
575 }
576 xas_unlock(&xas);
577 } while (xas_nomem(&xas, GFP_KERNEL));
578
579 ret = xas_error(&xas);
580 if (ret)
581 goto out;
582
583 wake_up_all(&cache->daemon_pollwq);
584 wait:
585 ret = wait_for_completion_killable(&req->done);
586 if (!ret) {
587 ret = req->error;
588 } else {
589 ret = -EINTR;
590 if (!cachefiles_ondemand_finish_req(req, &xas, ret)) {
591 /* Someone will complete it soon. */
592 cpu_relax();
593 goto wait;
594 }
595 }
596 cachefiles_req_put(req);
597 return ret;
598 out:
599 /* Reset the object to close state in error handling path.
600 * If error occurs after creating the anonymous fd,
601 * cachefiles_ondemand_fd_release() will set object to close.
602 */
603 if (opcode == CACHEFILES_OP_OPEN &&
604 !cachefiles_ondemand_object_is_dropping(object))
605 cachefiles_ondemand_set_object_close(object);
606 kfree(req);
607 return ret;
608 }
609
cachefiles_ondemand_init_open_req(struct cachefiles_req * req,void * private)610 static int cachefiles_ondemand_init_open_req(struct cachefiles_req *req,
611 void *private)
612 {
613 struct cachefiles_object *object = req->object;
614 struct fscache_cookie *cookie = object->cookie;
615 struct fscache_volume *volume = object->volume->vcookie;
616 struct cachefiles_open *load = (void *)req->msg.data;
617 size_t volume_key_size, cookie_key_size;
618 void *volume_key, *cookie_key;
619
620 /*
621 * Volume key is a NUL-terminated string. key[0] stores strlen() of the
622 * string, followed by the content of the string (excluding '\0').
623 */
624 volume_key_size = volume->key[0] + 1;
625 volume_key = volume->key + 1;
626
627 /* Cookie key is binary data, which is netfs specific. */
628 cookie_key_size = cookie->key_len;
629 cookie_key = fscache_get_key(cookie);
630
631 if (!(object->cookie->advice & FSCACHE_ADV_WANT_CACHE_SIZE)) {
632 pr_err("WANT_CACHE_SIZE is needed for on-demand mode\n");
633 return -EINVAL;
634 }
635
636 load->volume_key_size = volume_key_size;
637 load->cookie_key_size = cookie_key_size;
638 memcpy(load->data, volume_key, volume_key_size);
639 memcpy(load->data + volume_key_size, cookie_key, cookie_key_size);
640
641 return 0;
642 }
643
cachefiles_ondemand_init_close_req(struct cachefiles_req * req,void * private)644 static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req,
645 void *private)
646 {
647 struct cachefiles_object *object = req->object;
648
649 if (!cachefiles_ondemand_object_is_open(object))
650 return -ENOENT;
651
652 trace_cachefiles_ondemand_close(object, &req->msg);
653 return 0;
654 }
655
656 struct cachefiles_read_ctx {
657 loff_t off;
658 size_t len;
659 };
660
cachefiles_ondemand_init_read_req(struct cachefiles_req * req,void * private)661 static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req,
662 void *private)
663 {
664 struct cachefiles_object *object = req->object;
665 struct cachefiles_read *load = (void *)req->msg.data;
666 struct cachefiles_read_ctx *read_ctx = private;
667
668 load->off = read_ctx->off;
669 load->len = read_ctx->len;
670 trace_cachefiles_ondemand_read(object, &req->msg, load);
671 return 0;
672 }
673
cachefiles_ondemand_init_object(struct cachefiles_object * object)674 int cachefiles_ondemand_init_object(struct cachefiles_object *object)
675 {
676 struct fscache_cookie *cookie = object->cookie;
677 struct fscache_volume *volume = object->volume->vcookie;
678 size_t volume_key_size, cookie_key_size, data_len;
679
680 if (!object->ondemand)
681 return 0;
682
683 /*
684 * CacheFiles will firstly check the cache file under the root cache
685 * directory. If the coherency check failed, it will fallback to
686 * creating a new tmpfile as the cache file. Reuse the previously
687 * allocated object ID if any.
688 */
689 if (cachefiles_ondemand_object_is_open(object))
690 return 0;
691
692 volume_key_size = volume->key[0] + 1;
693 cookie_key_size = cookie->key_len;
694 data_len = sizeof(struct cachefiles_open) +
695 volume_key_size + cookie_key_size;
696
697 return cachefiles_ondemand_send_req(object, CACHEFILES_OP_OPEN,
698 data_len, cachefiles_ondemand_init_open_req, NULL);
699 }
700
cachefiles_ondemand_clean_object(struct cachefiles_object * object)701 void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
702 {
703 unsigned long index;
704 struct cachefiles_req *req;
705 struct cachefiles_cache *cache;
706
707 if (!object->ondemand)
708 return;
709
710 cachefiles_ondemand_send_req(object, CACHEFILES_OP_CLOSE, 0,
711 cachefiles_ondemand_init_close_req, NULL);
712
713 if (!object->ondemand->ondemand_id)
714 return;
715
716 /* Cancel all requests for the object that is being dropped. */
717 cache = object->volume->cache;
718 xa_lock(&cache->reqs);
719 cachefiles_ondemand_set_object_dropping(object);
720 xa_for_each(&cache->reqs, index, req) {
721 if (req->object == object) {
722 req->error = -EIO;
723 complete(&req->done);
724 __xa_erase(&cache->reqs, index);
725 }
726 }
727 xa_unlock(&cache->reqs);
728
729 /* Wait for ondemand_object_worker() to finish to avoid UAF. */
730 cancel_work_sync(&object->ondemand->ondemand_work);
731 }
732
cachefiles_ondemand_init_obj_info(struct cachefiles_object * object,struct cachefiles_volume * volume)733 int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object,
734 struct cachefiles_volume *volume)
735 {
736 if (!cachefiles_in_ondemand_mode(volume->cache))
737 return 0;
738
739 object->ondemand = kzalloc(sizeof(struct cachefiles_ondemand_info),
740 GFP_KERNEL);
741 if (!object->ondemand)
742 return -ENOMEM;
743
744 object->ondemand->object = object;
745 spin_lock_init(&object->ondemand->lock);
746 INIT_WORK(&object->ondemand->ondemand_work, ondemand_object_worker);
747 return 0;
748 }
749
cachefiles_ondemand_deinit_obj_info(struct cachefiles_object * object)750 void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *object)
751 {
752 kfree(object->ondemand);
753 object->ondemand = NULL;
754 }
755
cachefiles_ondemand_read(struct cachefiles_object * object,loff_t pos,size_t len)756 int cachefiles_ondemand_read(struct cachefiles_object *object,
757 loff_t pos, size_t len)
758 {
759 struct cachefiles_read_ctx read_ctx = {pos, len};
760
761 return cachefiles_ondemand_send_req(object, CACHEFILES_OP_READ,
762 sizeof(struct cachefiles_read),
763 cachefiles_ondemand_init_read_req, &read_ctx);
764 }
765