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