1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Daemon interface
3 *
4 * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/sched.h>
11 #include <linux/completion.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14 #include <linux/file.h>
15 #include <linux/namei.h>
16 #include <linux/poll.h>
17 #include <linux/mount.h>
18 #include <linux/statfs.h>
19 #include <linux/ctype.h>
20 #include <linux/string.h>
21 #include <linux/fs_struct.h>
22 #include "internal.h"
23
24 static int cachefiles_daemon_open(struct inode *, struct file *);
25 static int cachefiles_daemon_release(struct inode *, struct file *);
26 static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
27 loff_t *);
28 static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
29 size_t, loff_t *);
30 static __poll_t cachefiles_daemon_poll(struct file *,
31 struct poll_table_struct *);
32 static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
33 static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
34 static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
35 static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
36 static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
37 static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
38 static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
39 static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
40 static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
41 static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
42 static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
43 static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
44 static int cachefiles_daemon_bind(struct cachefiles_cache *, char *);
45 static void cachefiles_daemon_unbind(struct cachefiles_cache *);
46
47 static unsigned long cachefiles_open;
48
49 const struct file_operations cachefiles_daemon_fops = {
50 .owner = THIS_MODULE,
51 .open = cachefiles_daemon_open,
52 .release = cachefiles_daemon_release,
53 .read = cachefiles_daemon_read,
54 .write = cachefiles_daemon_write,
55 .poll = cachefiles_daemon_poll,
56 .llseek = noop_llseek,
57 };
58
59 struct cachefiles_daemon_cmd {
60 char name[8];
61 int (*handler)(struct cachefiles_cache *cache, char *args);
62 };
63
64 static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
65 { "bind", cachefiles_daemon_bind },
66 { "brun", cachefiles_daemon_brun },
67 { "bcull", cachefiles_daemon_bcull },
68 { "bstop", cachefiles_daemon_bstop },
69 { "cull", cachefiles_daemon_cull },
70 { "debug", cachefiles_daemon_debug },
71 { "dir", cachefiles_daemon_dir },
72 { "frun", cachefiles_daemon_frun },
73 { "fcull", cachefiles_daemon_fcull },
74 { "fstop", cachefiles_daemon_fstop },
75 { "inuse", cachefiles_daemon_inuse },
76 { "secctx", cachefiles_daemon_secctx },
77 { "tag", cachefiles_daemon_tag },
78 #ifdef CONFIG_CACHEFILES_ONDEMAND
79 { "copen", cachefiles_ondemand_copen },
80 #endif
81 { "", NULL }
82 };
83
84
85 /*
86 * Prepare a cache for caching.
87 */
cachefiles_daemon_open(struct inode * inode,struct file * file)88 static int cachefiles_daemon_open(struct inode *inode, struct file *file)
89 {
90 struct cachefiles_cache *cache;
91
92 _enter("");
93
94 /* only the superuser may do this */
95 if (!capable(CAP_SYS_ADMIN))
96 return -EPERM;
97
98 /* the cachefiles device may only be open once at a time */
99 if (xchg(&cachefiles_open, 1) == 1)
100 return -EBUSY;
101
102 /* allocate a cache record */
103 cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
104 if (!cache) {
105 cachefiles_open = 0;
106 return -ENOMEM;
107 }
108
109 mutex_init(&cache->daemon_mutex);
110 init_waitqueue_head(&cache->daemon_pollwq);
111 INIT_LIST_HEAD(&cache->volumes);
112 INIT_LIST_HEAD(&cache->object_list);
113 spin_lock_init(&cache->object_list_lock);
114 refcount_set(&cache->unbind_pincount, 1);
115 xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
116 xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);
117
118 /* set default caching limits
119 * - limit at 1% free space and/or free files
120 * - cull below 5% free space and/or free files
121 * - cease culling above 7% free space and/or free files
122 */
123 cache->frun_percent = 7;
124 cache->fcull_percent = 5;
125 cache->fstop_percent = 1;
126 cache->brun_percent = 7;
127 cache->bcull_percent = 5;
128 cache->bstop_percent = 1;
129
130 file->private_data = cache;
131 cache->cachefilesd = file;
132 return 0;
133 }
134
cachefiles_flush_reqs(struct cachefiles_cache * cache)135 static void cachefiles_flush_reqs(struct cachefiles_cache *cache)
136 {
137 struct xarray *xa = &cache->reqs;
138 struct cachefiles_req *req;
139 unsigned long index;
140
141 /*
142 * Make sure the following two operations won't be reordered.
143 * 1) set CACHEFILES_DEAD bit
144 * 2) flush requests in the xarray
145 * Otherwise the request may be enqueued after xarray has been
146 * flushed, leaving the orphan request never being completed.
147 *
148 * CPU 1 CPU 2
149 * ===== =====
150 * flush requests in the xarray
151 * test CACHEFILES_DEAD bit
152 * enqueue the request
153 * set CACHEFILES_DEAD bit
154 */
155 smp_mb();
156
157 xa_lock(xa);
158 xa_for_each(xa, index, req) {
159 req->error = -EIO;
160 complete(&req->done);
161 }
162 xa_unlock(xa);
163
164 xa_destroy(&cache->reqs);
165 xa_destroy(&cache->ondemand_ids);
166 }
167
cachefiles_put_unbind_pincount(struct cachefiles_cache * cache)168 void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
169 {
170 if (refcount_dec_and_test(&cache->unbind_pincount)) {
171 cachefiles_daemon_unbind(cache);
172 cachefiles_open = 0;
173 kfree(cache);
174 }
175 }
176
cachefiles_get_unbind_pincount(struct cachefiles_cache * cache)177 void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
178 {
179 refcount_inc(&cache->unbind_pincount);
180 }
181
182 /*
183 * Release a cache.
184 */
cachefiles_daemon_release(struct inode * inode,struct file * file)185 static int cachefiles_daemon_release(struct inode *inode, struct file *file)
186 {
187 struct cachefiles_cache *cache = file->private_data;
188
189 _enter("");
190
191 ASSERT(cache);
192
193 set_bit(CACHEFILES_DEAD, &cache->flags);
194
195 if (cachefiles_in_ondemand_mode(cache))
196 cachefiles_flush_reqs(cache);
197
198 /* clean up the control file interface */
199 cache->cachefilesd = NULL;
200 file->private_data = NULL;
201
202 cachefiles_put_unbind_pincount(cache);
203
204 _leave("");
205 return 0;
206 }
207
cachefiles_do_daemon_read(struct cachefiles_cache * cache,char __user * _buffer,size_t buflen)208 static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
209 char __user *_buffer, size_t buflen)
210 {
211 unsigned long long b_released;
212 unsigned f_released;
213 char buffer[256];
214 int n;
215
216 /* check how much space the cache has */
217 cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
218
219 /* summarise */
220 f_released = atomic_xchg(&cache->f_released, 0);
221 b_released = atomic_long_xchg(&cache->b_released, 0);
222 clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
223
224 n = snprintf(buffer, sizeof(buffer),
225 "cull=%c"
226 " frun=%llx"
227 " fcull=%llx"
228 " fstop=%llx"
229 " brun=%llx"
230 " bcull=%llx"
231 " bstop=%llx"
232 " freleased=%x"
233 " breleased=%llx",
234 test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
235 (unsigned long long) cache->frun,
236 (unsigned long long) cache->fcull,
237 (unsigned long long) cache->fstop,
238 (unsigned long long) cache->brun,
239 (unsigned long long) cache->bcull,
240 (unsigned long long) cache->bstop,
241 f_released,
242 b_released);
243
244 if (n > buflen)
245 return -EMSGSIZE;
246
247 if (copy_to_user(_buffer, buffer, n) != 0)
248 return -EFAULT;
249
250 return n;
251 }
252
253 /*
254 * Read the cache state.
255 */
cachefiles_daemon_read(struct file * file,char __user * _buffer,size_t buflen,loff_t * pos)256 static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
257 size_t buflen, loff_t *pos)
258 {
259 struct cachefiles_cache *cache = file->private_data;
260
261 //_enter(",,%zu,", buflen);
262
263 if (!test_bit(CACHEFILES_READY, &cache->flags))
264 return 0;
265
266 if (cachefiles_in_ondemand_mode(cache))
267 return cachefiles_ondemand_daemon_read(cache, _buffer, buflen);
268 else
269 return cachefiles_do_daemon_read(cache, _buffer, buflen);
270 }
271
272 /*
273 * Take a command from cachefilesd, parse it and act on it.
274 */
cachefiles_daemon_write(struct file * file,const char __user * _data,size_t datalen,loff_t * pos)275 static ssize_t cachefiles_daemon_write(struct file *file,
276 const char __user *_data,
277 size_t datalen,
278 loff_t *pos)
279 {
280 const struct cachefiles_daemon_cmd *cmd;
281 struct cachefiles_cache *cache = file->private_data;
282 ssize_t ret;
283 char *data, *args, *cp;
284
285 //_enter(",,%zu,", datalen);
286
287 ASSERT(cache);
288
289 if (test_bit(CACHEFILES_DEAD, &cache->flags))
290 return -EIO;
291
292 if (datalen > PAGE_SIZE - 1)
293 return -EOPNOTSUPP;
294
295 /* drag the command string into the kernel so we can parse it */
296 data = memdup_user_nul(_data, datalen);
297 if (IS_ERR(data))
298 return PTR_ERR(data);
299
300 ret = -EINVAL;
301 if (memchr(data, '\0', datalen))
302 goto error;
303
304 /* strip any newline */
305 cp = memchr(data, '\n', datalen);
306 if (cp) {
307 if (cp == data)
308 goto error;
309
310 *cp = '\0';
311 }
312
313 /* parse the command */
314 ret = -EOPNOTSUPP;
315
316 for (args = data; *args; args++)
317 if (isspace(*args))
318 break;
319 if (*args) {
320 if (args == data)
321 goto error;
322 *args = '\0';
323 args = skip_spaces(++args);
324 }
325
326 /* run the appropriate command handler */
327 for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
328 if (strcmp(cmd->name, data) == 0)
329 goto found_command;
330
331 error:
332 kfree(data);
333 //_leave(" = %zd", ret);
334 return ret;
335
336 found_command:
337 mutex_lock(&cache->daemon_mutex);
338
339 ret = -EIO;
340 if (!test_bit(CACHEFILES_DEAD, &cache->flags))
341 ret = cmd->handler(cache, args);
342
343 mutex_unlock(&cache->daemon_mutex);
344
345 if (ret == 0)
346 ret = datalen;
347 goto error;
348 }
349
350 /*
351 * Poll for culling state
352 * - use EPOLLOUT to indicate culling state
353 */
cachefiles_daemon_poll(struct file * file,struct poll_table_struct * poll)354 static __poll_t cachefiles_daemon_poll(struct file *file,
355 struct poll_table_struct *poll)
356 {
357 struct cachefiles_cache *cache = file->private_data;
358 __poll_t mask;
359
360 poll_wait(file, &cache->daemon_pollwq, poll);
361 mask = 0;
362
363 if (cachefiles_in_ondemand_mode(cache)) {
364 if (!xa_empty(&cache->reqs))
365 mask |= EPOLLIN;
366 } else {
367 if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
368 mask |= EPOLLIN;
369 }
370
371 if (test_bit(CACHEFILES_CULLING, &cache->flags))
372 mask |= EPOLLOUT;
373
374 return mask;
375 }
376
377 /*
378 * Give a range error for cache space constraints
379 * - can be tail-called
380 */
cachefiles_daemon_range_error(struct cachefiles_cache * cache,char * args)381 static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
382 char *args)
383 {
384 pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
385
386 return -EINVAL;
387 }
388
389 /*
390 * Set the percentage of files at which to stop culling
391 * - command: "frun <N>%"
392 */
cachefiles_daemon_frun(struct cachefiles_cache * cache,char * args)393 static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
394 {
395 unsigned long frun;
396
397 _enter(",%s", args);
398
399 if (!*args)
400 return -EINVAL;
401
402 frun = simple_strtoul(args, &args, 10);
403 if (args[0] != '%' || args[1] != '\0')
404 return -EINVAL;
405
406 if (frun <= cache->fcull_percent || frun >= 100)
407 return cachefiles_daemon_range_error(cache, args);
408
409 cache->frun_percent = frun;
410 return 0;
411 }
412
413 /*
414 * Set the percentage of files at which to start culling
415 * - command: "fcull <N>%"
416 */
cachefiles_daemon_fcull(struct cachefiles_cache * cache,char * args)417 static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
418 {
419 unsigned long fcull;
420
421 _enter(",%s", args);
422
423 if (!*args)
424 return -EINVAL;
425
426 fcull = simple_strtoul(args, &args, 10);
427 if (args[0] != '%' || args[1] != '\0')
428 return -EINVAL;
429
430 if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
431 return cachefiles_daemon_range_error(cache, args);
432
433 cache->fcull_percent = fcull;
434 return 0;
435 }
436
437 /*
438 * Set the percentage of files at which to stop allocating
439 * - command: "fstop <N>%"
440 */
cachefiles_daemon_fstop(struct cachefiles_cache * cache,char * args)441 static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
442 {
443 unsigned long fstop;
444
445 _enter(",%s", args);
446
447 if (!*args)
448 return -EINVAL;
449
450 fstop = simple_strtoul(args, &args, 10);
451 if (args[0] != '%' || args[1] != '\0')
452 return -EINVAL;
453
454 if (fstop >= cache->fcull_percent)
455 return cachefiles_daemon_range_error(cache, args);
456
457 cache->fstop_percent = fstop;
458 return 0;
459 }
460
461 /*
462 * Set the percentage of blocks at which to stop culling
463 * - command: "brun <N>%"
464 */
cachefiles_daemon_brun(struct cachefiles_cache * cache,char * args)465 static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
466 {
467 unsigned long brun;
468
469 _enter(",%s", args);
470
471 if (!*args)
472 return -EINVAL;
473
474 brun = simple_strtoul(args, &args, 10);
475 if (args[0] != '%' || args[1] != '\0')
476 return -EINVAL;
477
478 if (brun <= cache->bcull_percent || brun >= 100)
479 return cachefiles_daemon_range_error(cache, args);
480
481 cache->brun_percent = brun;
482 return 0;
483 }
484
485 /*
486 * Set the percentage of blocks at which to start culling
487 * - command: "bcull <N>%"
488 */
cachefiles_daemon_bcull(struct cachefiles_cache * cache,char * args)489 static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
490 {
491 unsigned long bcull;
492
493 _enter(",%s", args);
494
495 if (!*args)
496 return -EINVAL;
497
498 bcull = simple_strtoul(args, &args, 10);
499 if (args[0] != '%' || args[1] != '\0')
500 return -EINVAL;
501
502 if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
503 return cachefiles_daemon_range_error(cache, args);
504
505 cache->bcull_percent = bcull;
506 return 0;
507 }
508
509 /*
510 * Set the percentage of blocks at which to stop allocating
511 * - command: "bstop <N>%"
512 */
cachefiles_daemon_bstop(struct cachefiles_cache * cache,char * args)513 static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
514 {
515 unsigned long bstop;
516
517 _enter(",%s", args);
518
519 if (!*args)
520 return -EINVAL;
521
522 bstop = simple_strtoul(args, &args, 10);
523 if (args[0] != '%' || args[1] != '\0')
524 return -EINVAL;
525
526 if (bstop >= cache->bcull_percent)
527 return cachefiles_daemon_range_error(cache, args);
528
529 cache->bstop_percent = bstop;
530 return 0;
531 }
532
533 /*
534 * Set the cache directory
535 * - command: "dir <name>"
536 */
cachefiles_daemon_dir(struct cachefiles_cache * cache,char * args)537 static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
538 {
539 char *dir;
540
541 _enter(",%s", args);
542
543 if (!*args) {
544 pr_err("Empty directory specified\n");
545 return -EINVAL;
546 }
547
548 if (cache->rootdirname) {
549 pr_err("Second cache directory specified\n");
550 return -EEXIST;
551 }
552
553 dir = kstrdup(args, GFP_KERNEL);
554 if (!dir)
555 return -ENOMEM;
556
557 cache->rootdirname = dir;
558 return 0;
559 }
560
561 /*
562 * Set the cache security context
563 * - command: "secctx <ctx>"
564 */
cachefiles_daemon_secctx(struct cachefiles_cache * cache,char * args)565 static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
566 {
567 char *secctx;
568
569 _enter(",%s", args);
570
571 if (!*args) {
572 pr_err("Empty security context specified\n");
573 return -EINVAL;
574 }
575
576 if (cache->secctx) {
577 pr_err("Second security context specified\n");
578 return -EINVAL;
579 }
580
581 secctx = kstrdup(args, GFP_KERNEL);
582 if (!secctx)
583 return -ENOMEM;
584
585 cache->secctx = secctx;
586 return 0;
587 }
588
589 /*
590 * Set the cache tag
591 * - command: "tag <name>"
592 */
cachefiles_daemon_tag(struct cachefiles_cache * cache,char * args)593 static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
594 {
595 char *tag;
596
597 _enter(",%s", args);
598
599 if (!*args) {
600 pr_err("Empty tag specified\n");
601 return -EINVAL;
602 }
603
604 if (cache->tag)
605 return -EEXIST;
606
607 tag = kstrdup(args, GFP_KERNEL);
608 if (!tag)
609 return -ENOMEM;
610
611 cache->tag = tag;
612 return 0;
613 }
614
615 /*
616 * Request a node in the cache be culled from the current working directory
617 * - command: "cull <name>"
618 */
cachefiles_daemon_cull(struct cachefiles_cache * cache,char * args)619 static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
620 {
621 struct path path;
622 const struct cred *saved_cred;
623 int ret;
624
625 _enter(",%s", args);
626
627 if (strchr(args, '/'))
628 goto inval;
629
630 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
631 pr_err("cull applied to unready cache\n");
632 return -EIO;
633 }
634
635 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
636 pr_err("cull applied to dead cache\n");
637 return -EIO;
638 }
639
640 get_fs_pwd(current->fs, &path);
641
642 if (!d_can_lookup(path.dentry))
643 goto notdir;
644
645 cachefiles_begin_secure(cache, &saved_cred);
646 ret = cachefiles_cull(cache, path.dentry, args);
647 cachefiles_end_secure(cache, saved_cred);
648
649 path_put(&path);
650 _leave(" = %d", ret);
651 return ret;
652
653 notdir:
654 path_put(&path);
655 pr_err("cull command requires dirfd to be a directory\n");
656 return -ENOTDIR;
657
658 inval:
659 pr_err("cull command requires dirfd and filename\n");
660 return -EINVAL;
661 }
662
663 /*
664 * Set debugging mode
665 * - command: "debug <mask>"
666 */
cachefiles_daemon_debug(struct cachefiles_cache * cache,char * args)667 static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
668 {
669 unsigned long mask;
670
671 _enter(",%s", args);
672
673 mask = simple_strtoul(args, &args, 0);
674 if (args[0] != '\0')
675 goto inval;
676
677 cachefiles_debug = mask;
678 _leave(" = 0");
679 return 0;
680
681 inval:
682 pr_err("debug command requires mask\n");
683 return -EINVAL;
684 }
685
686 /*
687 * Find out whether an object in the current working directory is in use or not
688 * - command: "inuse <name>"
689 */
cachefiles_daemon_inuse(struct cachefiles_cache * cache,char * args)690 static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
691 {
692 struct path path;
693 const struct cred *saved_cred;
694 int ret;
695
696 //_enter(",%s", args);
697
698 if (strchr(args, '/'))
699 goto inval;
700
701 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
702 pr_err("inuse applied to unready cache\n");
703 return -EIO;
704 }
705
706 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
707 pr_err("inuse applied to dead cache\n");
708 return -EIO;
709 }
710
711 get_fs_pwd(current->fs, &path);
712
713 if (!d_can_lookup(path.dentry))
714 goto notdir;
715
716 cachefiles_begin_secure(cache, &saved_cred);
717 ret = cachefiles_check_in_use(cache, path.dentry, args);
718 cachefiles_end_secure(cache, saved_cred);
719
720 path_put(&path);
721 //_leave(" = %d", ret);
722 return ret;
723
724 notdir:
725 path_put(&path);
726 pr_err("inuse command requires dirfd to be a directory\n");
727 return -ENOTDIR;
728
729 inval:
730 pr_err("inuse command requires dirfd and filename\n");
731 return -EINVAL;
732 }
733
734 /*
735 * Bind a directory as a cache
736 */
cachefiles_daemon_bind(struct cachefiles_cache * cache,char * args)737 static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
738 {
739 _enter("{%u,%u,%u,%u,%u,%u},%s",
740 cache->frun_percent,
741 cache->fcull_percent,
742 cache->fstop_percent,
743 cache->brun_percent,
744 cache->bcull_percent,
745 cache->bstop_percent,
746 args);
747
748 if (cache->fstop_percent >= cache->fcull_percent ||
749 cache->fcull_percent >= cache->frun_percent ||
750 cache->frun_percent >= 100)
751 return -ERANGE;
752
753 if (cache->bstop_percent >= cache->bcull_percent ||
754 cache->bcull_percent >= cache->brun_percent ||
755 cache->brun_percent >= 100)
756 return -ERANGE;
757
758 if (!cache->rootdirname) {
759 pr_err("No cache directory specified\n");
760 return -EINVAL;
761 }
762
763 /* Don't permit already bound caches to be re-bound */
764 if (test_bit(CACHEFILES_READY, &cache->flags)) {
765 pr_err("Cache already bound\n");
766 return -EBUSY;
767 }
768
769 if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) {
770 if (!strcmp(args, "ondemand")) {
771 set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
772 } else if (*args) {
773 pr_err("Invalid argument to the 'bind' command\n");
774 return -EINVAL;
775 }
776 } else if (*args) {
777 pr_err("'bind' command doesn't take an argument\n");
778 return -EINVAL;
779 }
780
781 /* Make sure we have copies of the tag string */
782 if (!cache->tag) {
783 /*
784 * The tag string is released by the fops->release()
785 * function, so we don't release it on error here
786 */
787 cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
788 if (!cache->tag)
789 return -ENOMEM;
790 }
791
792 return cachefiles_add_cache(cache);
793 }
794
795 /*
796 * Unbind a cache.
797 */
cachefiles_daemon_unbind(struct cachefiles_cache * cache)798 static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
799 {
800 _enter("");
801
802 if (test_bit(CACHEFILES_READY, &cache->flags))
803 cachefiles_withdraw_cache(cache);
804
805 cachefiles_put_directory(cache->graveyard);
806 cachefiles_put_directory(cache->store);
807 mntput(cache->mnt);
808
809 kfree(cache->rootdirname);
810 kfree(cache->secctx);
811 kfree(cache->tag);
812
813 _leave("");
814 }
815