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Merge tag 'mm-hotfixes-stable-2025-07-11-16-16' of git://git.kernel.org/pub/scm/linux...
[linux-2.6-block.git] / fs / cachefiles / daemon.c
CommitLineData
8667d434
DH		 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>
e5a8b644 18#include <linux/security.h>
8667d434
DH		 19#include <linux/statfs.h>
20#include <linux/ctype.h>
21#include <linux/string.h>
22#include <linux/fs_struct.h>
23#include "internal.h"
24
25static int cachefiles_daemon_open(struct inode *, struct file *);
26static int cachefiles_daemon_release(struct inode *, struct file *);
27static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
28 loff_t *);
29static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
30 size_t, loff_t *);
31static __poll_t cachefiles_daemon_poll(struct file *,
32 struct poll_table_struct *);
33static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
34static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
35static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
36static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
37static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
38static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
39static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
40static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
41static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
42static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
43static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
44static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
45static int cachefiles_daemon_bind(struct cachefiles_cache *, char *);
46static void cachefiles_daemon_unbind(struct cachefiles_cache *);
47
48static unsigned long cachefiles_open;
49
50const struct file_operations cachefiles_daemon_fops = {
51 .owner = THIS_MODULE,
52 .open = cachefiles_daemon_open,
53 .release = cachefiles_daemon_release,
54 .read = cachefiles_daemon_read,
55 .write = cachefiles_daemon_write,
56 .poll = cachefiles_daemon_poll,
57 .llseek = noop_llseek,
58};
59
60struct cachefiles_daemon_cmd {
61 char name[8];
62 int (*handler)(struct cachefiles_cache *cache, char *args);
63};
64
65static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
66 { "bind", cachefiles_daemon_bind },
67 { "brun", cachefiles_daemon_brun },
68 { "bcull", cachefiles_daemon_bcull },
69 { "bstop", cachefiles_daemon_bstop },
70 { "cull", cachefiles_daemon_cull },
71 { "debug", cachefiles_daemon_debug },
72 { "dir", cachefiles_daemon_dir },
73 { "frun", cachefiles_daemon_frun },
74 { "fcull", cachefiles_daemon_fcull },
75 { "fstop", cachefiles_daemon_fstop },
76 { "inuse", cachefiles_daemon_inuse },
77 { "secctx", cachefiles_daemon_secctx },
78 { "tag", cachefiles_daemon_tag },
c8383054
JX		 79#ifdef CONFIG_CACHEFILES_ONDEMAND
80 { "copen", cachefiles_ondemand_copen },
e73fa11a 81 { "restore", cachefiles_ondemand_restore },
c8383054 82#endif
8667d434
DH		 83 { "", NULL }
84};
85
86
87/*
88 * Prepare a cache for caching.
89 */
90static int cachefiles_daemon_open(struct inode *inode, struct file *file)
91{
92 struct cachefiles_cache *cache;
93
94 _enter("");
95
96 /* only the superuser may do this */
97 if (!capable(CAP_SYS_ADMIN))
98 return -EPERM;
99
100 /* the cachefiles device may only be open once at a time */
101 if (xchg(&cachefiles_open, 1) == 1)
102 return -EBUSY;
103
104 /* allocate a cache record */
105 cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
106 if (!cache) {
107 cachefiles_open = 0;
108 return -ENOMEM;
109 }
110
111 mutex_init(&cache->daemon_mutex);
112 init_waitqueue_head(&cache->daemon_pollwq);
fe2140e2 113 INIT_LIST_HEAD(&cache->volumes);
1f08c925 114 INIT_LIST_HEAD(&cache->object_list);
fe2140e2 115 spin_lock_init(&cache->object_list_lock);
d11b0b04 116 refcount_set(&cache->unbind_pincount, 1);
c8383054
JX		 117 xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
118 xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);
8667d434
DH		 119
120 /* set default caching limits
121 * - limit at 1% free space and/or free files
122 * - cull below 5% free space and/or free files
123 * - cease culling above 7% free space and/or free files
124 */
125 cache->frun_percent = 7;
126 cache->fcull_percent = 5;
127 cache->fstop_percent = 1;
128 cache->brun_percent = 7;
129 cache->bcull_percent = 5;
130 cache->bstop_percent = 1;
131
132 file->private_data = cache;
133 cache->cachefilesd = file;
134 return 0;
135}
136
85e833cd 137void cachefiles_flush_reqs(struct cachefiles_cache *cache)
c8383054
JX		 138{
139 struct xarray *xa = &cache->reqs;
140 struct cachefiles_req *req;
141 unsigned long index;
142
143 /*
144 * Make sure the following two operations won't be reordered.
145 * 1) set CACHEFILES_DEAD bit
146 * 2) flush requests in the xarray
147 * Otherwise the request may be enqueued after xarray has been
148 * flushed, leaving the orphan request never being completed.
149 *
150 * CPU 1 CPU 2
151 * ===== =====
152 * flush requests in the xarray
153 * test CACHEFILES_DEAD bit
154 * enqueue the request
155 * set CACHEFILES_DEAD bit
156 */
157 smp_mb();
158
159 xa_lock(xa);
160 xa_for_each(xa, index, req) {
161 req->error = -EIO;
162 complete(&req->done);
0fc75c59 163 __xa_erase(xa, index);
c8383054
JX		 164 }
165 xa_unlock(xa);
166
167 xa_destroy(&cache->reqs);
168 xa_destroy(&cache->ondemand_ids);
169}
170
d11b0b04
JX		 171void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
172{
173 if (refcount_dec_and_test(&cache->unbind_pincount)) {
174 cachefiles_daemon_unbind(cache);
175 cachefiles_open = 0;
176 kfree(cache);
177 }
178}
179
180void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
181{
182 refcount_inc(&cache->unbind_pincount);
183}
184
8667d434
DH		 185/*
186 * Release a cache.
187 */
188static int cachefiles_daemon_release(struct inode *inode, struct file *file)
189{
190 struct cachefiles_cache *cache = file->private_data;
191
192 _enter("");
193
194 ASSERT(cache);
195
196 set_bit(CACHEFILES_DEAD, &cache->flags);
197
c8383054
JX		 198 if (cachefiles_in_ondemand_mode(cache))
199 cachefiles_flush_reqs(cache);
8667d434
DH		 200
201 /* clean up the control file interface */
202 cache->cachefilesd = NULL;
203 file->private_data = NULL;
8667d434 204
d11b0b04 205 cachefiles_put_unbind_pincount(cache);
8667d434
DH		 206
207 _leave("");
208 return 0;
209}
210
c8383054
JX		 211static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
212 char __user *_buffer, size_t buflen)
8667d434 213{
8667d434
DH		 214 unsigned long long b_released;
215 unsigned f_released;
216 char buffer[256];
217 int n;
218
8667d434 219 /* check how much space the cache has */
3929eca7 220 cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
8667d434
DH		 221
222 /* summarise */
223 f_released = atomic_xchg(&cache->f_released, 0);
224 b_released = atomic_long_xchg(&cache->b_released, 0);
225 clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
226
227 n = snprintf(buffer, sizeof(buffer),
228 "cull=%c"
229 " frun=%llx"
230 " fcull=%llx"
231 " fstop=%llx"
232 " brun=%llx"
233 " bcull=%llx"
234 " bstop=%llx"
235 " freleased=%x"
236 " breleased=%llx",
237 test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
238 (unsigned long long) cache->frun,
239 (unsigned long long) cache->fcull,
240 (unsigned long long) cache->fstop,
241 (unsigned long long) cache->brun,
242 (unsigned long long) cache->bcull,
243 (unsigned long long) cache->bstop,
244 f_released,
245 b_released);
246
247 if (n > buflen)
248 return -EMSGSIZE;
249
250 if (copy_to_user(_buffer, buffer, n) != 0)
251 return -EFAULT;
252
253 return n;
254}
255
c8383054
JX		 256/*
257 * Read the cache state.
258 */
259static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
260 size_t buflen, loff_t *pos)
261{
262 struct cachefiles_cache *cache = file->private_data;
263
264 //_enter(",,%zu,", buflen);
265
266 if (!test_bit(CACHEFILES_READY, &cache->flags))
267 return 0;
268
269 if (cachefiles_in_ondemand_mode(cache))
270 return cachefiles_ondemand_daemon_read(cache, _buffer, buflen);
271 else
272 return cachefiles_do_daemon_read(cache, _buffer, buflen);
273}
274
8667d434
DH		 275/*
276 * Take a command from cachefilesd, parse it and act on it.
277 */
278static ssize_t cachefiles_daemon_write(struct file *file,
279 const char __user *_data,
280 size_t datalen,
281 loff_t *pos)
282{
283 const struct cachefiles_daemon_cmd *cmd;
284 struct cachefiles_cache *cache = file->private_data;
285 ssize_t ret;
286 char *data, *args, *cp;
287
288 //_enter(",,%zu,", datalen);
289
290 ASSERT(cache);
291
292 if (test_bit(CACHEFILES_DEAD, &cache->flags))
293 return -EIO;
294
295 if (datalen > PAGE_SIZE - 1)
296 return -EOPNOTSUPP;
297
298 /* drag the command string into the kernel so we can parse it */
299 data = memdup_user_nul(_data, datalen);
300 if (IS_ERR(data))
301 return PTR_ERR(data);
302
303 ret = -EINVAL;
304 if (memchr(data, '\0', datalen))
305 goto error;
306
307 /* strip any newline */
308 cp = memchr(data, '\n', datalen);
309 if (cp) {
310 if (cp == data)
311 goto error;
312
313 *cp = '\0';
314 }
315
316 /* parse the command */
317 ret = -EOPNOTSUPP;
318
319 for (args = data; *args; args++)
320 if (isspace(*args))
321 break;
322 if (*args) {
323 if (args == data)
324 goto error;
325 *args = '\0';
326 args = skip_spaces(++args);
327 }
328
329 /* run the appropriate command handler */
330 for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
331 if (strcmp(cmd->name, data) == 0)
332 goto found_command;
333
334error:
335 kfree(data);
336 //_leave(" = %zd", ret);
337 return ret;
338
339found_command:
340 mutex_lock(&cache->daemon_mutex);
341
342 ret = -EIO;
343 if (!test_bit(CACHEFILES_DEAD, &cache->flags))
344 ret = cmd->handler(cache, args);
345
346 mutex_unlock(&cache->daemon_mutex);
347
348 if (ret == 0)
349 ret = datalen;
350 goto error;
351}
352
353/*
354 * Poll for culling state
355 * - use EPOLLOUT to indicate culling state
356 */
357static __poll_t cachefiles_daemon_poll(struct file *file,
358 struct poll_table_struct *poll)
359{
360 struct cachefiles_cache *cache = file->private_data;
b817e22b
JZ		 361 XA_STATE(xas, &cache->reqs, 0);
362 struct cachefiles_req *req;
8667d434
DH		 363 __poll_t mask;
364
365 poll_wait(file, &cache->daemon_pollwq, poll);
366 mask = 0;
367
c8383054 368 if (cachefiles_in_ondemand_mode(cache)) {
b817e22b 369 if (!xa_empty(&cache->reqs)) {
cf5bb09e 370 xas_lock(&xas);
b817e22b
JZ		 371 xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
372 if (!cachefiles_ondemand_is_reopening_read(req)) {
373 mask |= EPOLLIN;
374 break;
375 }
376 }
cf5bb09e 377 xas_unlock(&xas);
b817e22b 378 }
c8383054
JX		 379 } else {
380 if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
381 mask |= EPOLLIN;
382 }
8667d434
DH		 383
384 if (test_bit(CACHEFILES_CULLING, &cache->flags))
385 mask |= EPOLLOUT;
386
387 return mask;
388}
389
390/*
391 * Give a range error for cache space constraints
392 * - can be tail-called
393 */
394static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
395 char *args)
396{
397 pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
398
399 return -EINVAL;
400}
401
402/*
403 * Set the percentage of files at which to stop culling
404 * - command: "frun <N>%"
405 */
406static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
407{
408 unsigned long frun;
409
410 _enter(",%s", args);
411
412 if (!*args)
413 return -EINVAL;
414
415 frun = simple_strtoul(args, &args, 10);
416 if (args[0] != '%' || args[1] != '\0')
417 return -EINVAL;
418
419 if (frun <= cache->fcull_percent || frun >= 100)
420 return cachefiles_daemon_range_error(cache, args);
421
422 cache->frun_percent = frun;
423 return 0;
424}
425
426/*
427 * Set the percentage of files at which to start culling
428 * - command: "fcull <N>%"
429 */
430static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
431{
432 unsigned long fcull;
433
434 _enter(",%s", args);
435
436 if (!*args)
437 return -EINVAL;
438
439 fcull = simple_strtoul(args, &args, 10);
440 if (args[0] != '%' || args[1] != '\0')
441 return -EINVAL;
442
443 if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
444 return cachefiles_daemon_range_error(cache, args);
445
446 cache->fcull_percent = fcull;
447 return 0;
448}
449
450/*
451 * Set the percentage of files at which to stop allocating
452 * - command: "fstop <N>%"
453 */
454static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
455{
456 unsigned long fstop;
457
458 _enter(",%s", args);
459
460 if (!*args)
461 return -EINVAL;
462
463 fstop = simple_strtoul(args, &args, 10);
464 if (args[0] != '%' || args[1] != '\0')
465 return -EINVAL;
466
467 if (fstop >= cache->fcull_percent)
468 return cachefiles_daemon_range_error(cache, args);
469
470 cache->fstop_percent = fstop;
471 return 0;
472}
473
474/*
475 * Set the percentage of blocks at which to stop culling
476 * - command: "brun <N>%"
477 */
478static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
479{
480 unsigned long brun;
481
482 _enter(",%s", args);
483
484 if (!*args)
485 return -EINVAL;
486
487 brun = simple_strtoul(args, &args, 10);
488 if (args[0] != '%' || args[1] != '\0')
489 return -EINVAL;
490
491 if (brun <= cache->bcull_percent || brun >= 100)
492 return cachefiles_daemon_range_error(cache, args);
493
494 cache->brun_percent = brun;
495 return 0;
496}
497
498/*
499 * Set the percentage of blocks at which to start culling
500 * - command: "bcull <N>%"
501 */
502static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
503{
504 unsigned long bcull;
505
506 _enter(",%s", args);
507
508 if (!*args)
509 return -EINVAL;
510
511 bcull = simple_strtoul(args, &args, 10);
512 if (args[0] != '%' || args[1] != '\0')
513 return -EINVAL;
514
515 if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
516 return cachefiles_daemon_range_error(cache, args);
517
518 cache->bcull_percent = bcull;
519 return 0;
520}
521
522/*
523 * Set the percentage of blocks at which to stop allocating
524 * - command: "bstop <N>%"
525 */
526static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
527{
528 unsigned long bstop;
529
530 _enter(",%s", args);
531
532 if (!*args)
533 return -EINVAL;
534
535 bstop = simple_strtoul(args, &args, 10);
536 if (args[0] != '%' || args[1] != '\0')
537 return -EINVAL;
538
539 if (bstop >= cache->bcull_percent)
540 return cachefiles_daemon_range_error(cache, args);
541
542 cache->bstop_percent = bstop;
543 return 0;
544}
545
546/*
547 * Set the cache directory
548 * - command: "dir <name>"
549 */
550static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
551{
552 char *dir;
553
554 _enter(",%s", args);
555
556 if (!*args) {
557 pr_err("Empty directory specified\n");
558 return -EINVAL;
559 }
560
561 if (cache->rootdirname) {
562 pr_err("Second cache directory specified\n");
563 return -EEXIST;
564 }
565
566 dir = kstrdup(args, GFP_KERNEL);
567 if (!dir)
568 return -ENOMEM;
569
570 cache->rootdirname = dir;
571 return 0;
572}
573
574/*
575 * Set the cache security context
576 * - command: "secctx <ctx>"
577 */
578static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
579{
e5a8b644 580 int err;
8667d434
DH		 581
582 _enter(",%s", args);
583
584 if (!*args) {
585 pr_err("Empty security context specified\n");
586 return -EINVAL;
587 }
588
e5a8b644 589 if (cache->have_secid) {
8667d434
DH		 590 pr_err("Second security context specified\n");
591 return -EINVAL;
592 }
593
e5a8b644
MK		 594 err = security_secctx_to_secid(args, strlen(args), &cache->secid);
595 if (err)
596 return err;
8667d434 597
e5a8b644 598 cache->have_secid = true;
8667d434
DH		 599 return 0;
600}
601
602/*
603 * Set the cache tag
604 * - command: "tag <name>"
605 */
606static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
607{
608 char *tag;
609
610 _enter(",%s", args);
611
612 if (!*args) {
613 pr_err("Empty tag specified\n");
614 return -EINVAL;
615 }
616
617 if (cache->tag)
618 return -EEXIST;
619
620 tag = kstrdup(args, GFP_KERNEL);
621 if (!tag)
622 return -ENOMEM;
623
624 cache->tag = tag;
625 return 0;
626}
627
628/*
629 * Request a node in the cache be culled from the current working directory
630 * - command: "cull <name>"
631 */
632static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
633{
634 struct path path;
635 const struct cred *saved_cred;
636 int ret;
637
638 _enter(",%s", args);
639
640 if (strchr(args, '/'))
641 goto inval;
642
643 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
644 pr_err("cull applied to unready cache\n");
645 return -EIO;
646 }
647
648 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
649 pr_err("cull applied to dead cache\n");
650 return -EIO;
651 }
652
653 get_fs_pwd(current->fs, &path);
654
655 if (!d_can_lookup(path.dentry))
656 goto notdir;
657
658 cachefiles_begin_secure(cache, &saved_cred);
07a90e97 659 ret = cachefiles_cull(cache, path.dentry, args);
8667d434
DH		 660 cachefiles_end_secure(cache, saved_cred);
661
662 path_put(&path);
663 _leave(" = %d", ret);
664 return ret;
665
666notdir:
667 path_put(&path);
668 pr_err("cull command requires dirfd to be a directory\n");
669 return -ENOTDIR;
670
671inval:
672 pr_err("cull command requires dirfd and filename\n");
673 return -EINVAL;
674}
675
676/*
677 * Set debugging mode
678 * - command: "debug <mask>"
679 */
680static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
681{
682 unsigned long mask;
683
684 _enter(",%s", args);
685
686 mask = simple_strtoul(args, &args, 0);
687 if (args[0] != '\0')
688 goto inval;
689
690 cachefiles_debug = mask;
691 _leave(" = 0");
692 return 0;
693
694inval:
695 pr_err("debug command requires mask\n");
696 return -EINVAL;
697}
698
699/*
700 * Find out whether an object in the current working directory is in use or not
701 * - command: "inuse <name>"
702 */
703static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
704{
705 struct path path;
706 const struct cred *saved_cred;
707 int ret;
708
709 //_enter(",%s", args);
710
711 if (strchr(args, '/'))
712 goto inval;
713
714 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
715 pr_err("inuse applied to unready cache\n");
716 return -EIO;
717 }
718
719 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
720 pr_err("inuse applied to dead cache\n");
721 return -EIO;
722 }
723
724 get_fs_pwd(current->fs, &path);
725
726 if (!d_can_lookup(path.dentry))
727 goto notdir;
728
729 cachefiles_begin_secure(cache, &saved_cred);
07a90e97 730 ret = cachefiles_check_in_use(cache, path.dentry, args);
8667d434
DH		 731 cachefiles_end_secure(cache, saved_cred);
732
733 path_put(&path);
734 //_leave(" = %d", ret);
735 return ret;
736
737notdir:
738 path_put(&path);
739 pr_err("inuse command requires dirfd to be a directory\n");
740 return -ENOTDIR;
741
742inval:
743 pr_err("inuse command requires dirfd and filename\n");
744 return -EINVAL;
745}
746
747/*
748 * Bind a directory as a cache
749 */
750static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
751{
752 _enter("{%u,%u,%u,%u,%u,%u},%s",
753 cache->frun_percent,
754 cache->fcull_percent,
755 cache->fstop_percent,
756 cache->brun_percent,
757 cache->bcull_percent,
758 cache->bstop_percent,
759 args);
760
761 if (cache->fstop_percent >= cache->fcull_percent ||
762 cache->fcull_percent >= cache->frun_percent ||
763 cache->frun_percent >= 100)
764 return -ERANGE;
765
766 if (cache->bstop_percent >= cache->bcull_percent ||
767 cache->bcull_percent >= cache->brun_percent ||
768 cache->brun_percent >= 100)
769 return -ERANGE;
770
8667d434
DH		 771 if (!cache->rootdirname) {
772 pr_err("No cache directory specified\n");
773 return -EINVAL;
774 }
775
776 /* Don't permit already bound caches to be re-bound */
777 if (test_bit(CACHEFILES_READY, &cache->flags)) {
778 pr_err("Cache already bound\n");
779 return -EBUSY;
780 }
781
4e4f1788
JX		 782 if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) {
783 if (!strcmp(args, "ondemand")) {
784 set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
785 } else if (*args) {
786 pr_err("Invalid argument to the 'bind' command\n");
787 return -EINVAL;
788 }
789 } else if (*args) {
790 pr_err("'bind' command doesn't take an argument\n");
791 return -EINVAL;
792 }
793
c7ca7315
JX		 794 /* Make sure we have copies of the tag string */
795 if (!cache->tag) {
796 /*
797 * The tag string is released by the fops->release()
798 * function, so we don't release it on error here
799 */
800 cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
801 if (!cache->tag)
802 return -ENOMEM;
803 }
804
ecd1a5f6 805 return cachefiles_add_cache(cache);
8667d434
DH		 806}
807
808/*
809 * Unbind a cache.
810 */
811static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
812{
813 _enter("");
814
d1065b0a
DH		 815 if (test_bit(CACHEFILES_READY, &cache->flags))
816 cachefiles_withdraw_cache(cache);
8667d434 817
d1065b0a
DH		 818 cachefiles_put_directory(cache->graveyard);
819 cachefiles_put_directory(cache->store);
8667d434 820 mntput(cache->mnt);
e21a2f17 821 put_cred(cache->cache_cred);
8667d434
DH		 822
823 kfree(cache->rootdirname);
8667d434
DH		 824 kfree(cache->tag);
825
826 _leave("");
827}
Linux 6.x block layer and io_uring tree(s)