daemon.c

  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/security.h>
 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		},
 79#ifdef CONFIG_CACHEFILES_ONDEMAND
 80	{ "copen",	cachefiles_ondemand_copen	},
 81	{ "restore",	cachefiles_ondemand_restore	},
 82#endif
 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);
113	INIT_LIST_HEAD(&cache->volumes);
114	INIT_LIST_HEAD(&cache->object_list);
115	spin_lock_init(&cache->object_list_lock);
116	refcount_set(&cache->unbind_pincount, 1);
117	xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
118	xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);
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
137void cachefiles_flush_reqs(struct cachefiles_cache *cache)
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);
163		__xa_erase(xa, index);
164	}
165	xa_unlock(xa);
166
167	xa_destroy(&cache->reqs);
168	xa_destroy(&cache->ondemand_ids);
169}
170
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
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
198	if (cachefiles_in_ondemand_mode(cache))
199		cachefiles_flush_reqs(cache);
200
201	/* clean up the control file interface */
202	cache->cachefilesd = NULL;
203	file->private_data = NULL;
204
205	cachefiles_put_unbind_pincount(cache);
206
207	_leave("");
208	return 0;
209}
210
211static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
212					 char __user *_buffer, size_t buflen)
213{
214	unsigned long long b_released;
215	unsigned f_released;
216	char buffer[256];
217	int n;
218
219	/* check how much space the cache has */
220	cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
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
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
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;
361	XA_STATE(xas, &cache->reqs, 0);
362	struct cachefiles_req *req;
363	__poll_t mask;
364
365	poll_wait(file, &cache->daemon_pollwq, poll);
366	mask = 0;
367
368	if (cachefiles_in_ondemand_mode(cache)) {
369		if (!xa_empty(&cache->reqs)) {
370			xas_lock(&xas);
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			}
377			xas_unlock(&xas);
378		}
379	} else {
380		if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
381			mask |= EPOLLIN;
382	}
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{
580	int err;
581
582	_enter(",%s", args);
583
584	if (!*args) {
585		pr_err("Empty security context specified\n");
586		return -EINVAL;
587	}
588
589	if (cache->have_secid) {
590		pr_err("Second security context specified\n");
591		return -EINVAL;
592	}
593
594	err = security_secctx_to_secid(args, strlen(args), &cache->secid);
595	if (err)
596		return err;
597
598	cache->have_secid = true;
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);
659	ret = cachefiles_cull(cache, path.dentry, args);
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);
730	ret = cachefiles_check_in_use(cache, path.dentry, args);
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
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
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
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
805	return cachefiles_add_cache(cache);
806}
807
808/*
809 * Unbind a cache.
810 */
811static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
812{
813	_enter("");
814
815	if (test_bit(CACHEFILES_READY, &cache->flags))
816		cachefiles_withdraw_cache(cache);
817
818	cachefiles_put_directory(cache->graveyard);
819	cachefiles_put_directory(cache->store);
820	mntput(cache->mnt);
821	put_cred(cache->cache_cred);
822
823	kfree(cache->rootdirname);
824	kfree(cache->tag);
825
826	_leave("");
827}