[linux-2.6-block.git] / fs / cachefiles / daemon.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Daemon interface
 *
 * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/statfs.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/fs_struct.h>
#include "internal.h"

static int cachefiles_daemon_open(struct inode *, struct file *);
static int cachefiles_daemon_release(struct inode *, struct file *);
static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
				      loff_t *);
static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
				       size_t, loff_t *);
static __poll_t cachefiles_daemon_poll(struct file *,
					   struct poll_table_struct *);
static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
static int cachefiles_daemon_bind(struct cachefiles_cache *, char *);
static void cachefiles_daemon_unbind(struct cachefiles_cache *);

static unsigned long cachefiles_open;

const struct file_operations cachefiles_daemon_fops = {
	.owner		= THIS_MODULE,
	.open		= cachefiles_daemon_open,
	.release	= cachefiles_daemon_release,
	.read		= cachefiles_daemon_read,
	.write		= cachefiles_daemon_write,
	.poll		= cachefiles_daemon_poll,
	.llseek		= noop_llseek,
};

struct cachefiles_daemon_cmd {
	char name[8];
	int (*handler)(struct cachefiles_cache *cache, char *args);
};

static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
	{ "bind",	cachefiles_daemon_bind		},
	{ "brun",	cachefiles_daemon_brun		},
	{ "bcull",	cachefiles_daemon_bcull		},
	{ "bstop",	cachefiles_daemon_bstop		},
	{ "cull",	cachefiles_daemon_cull		},
	{ "debug",	cachefiles_daemon_debug		},
	{ "dir",	cachefiles_daemon_dir		},
	{ "frun",	cachefiles_daemon_frun		},
	{ "fcull",	cachefiles_daemon_fcull		},
	{ "fstop",	cachefiles_daemon_fstop		},
	{ "inuse",	cachefiles_daemon_inuse		},
	{ "secctx",	cachefiles_daemon_secctx	},
	{ "tag",	cachefiles_daemon_tag		},
#ifdef CONFIG_CACHEFILES_ONDEMAND
	{ "copen",	cachefiles_ondemand_copen	},
	{ "restore",	cachefiles_ondemand_restore	},
#endif
	{ "",		NULL				}
};


/*
 * Prepare a cache for caching.
 */
static int cachefiles_daemon_open(struct inode *inode, struct file *file)
{
	struct cachefiles_cache *cache;

	_enter("");

	/* only the superuser may do this */
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	/* the cachefiles device may only be open once at a time */
	if (xchg(&cachefiles_open, 1) == 1)
		return -EBUSY;

	/* allocate a cache record */
	cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
	if (!cache) {
		cachefiles_open = 0;
		return -ENOMEM;
	}

	mutex_init(&cache->daemon_mutex);
	init_waitqueue_head(&cache->daemon_pollwq);
	INIT_LIST_HEAD(&cache->volumes);
	INIT_LIST_HEAD(&cache->object_list);
	spin_lock_init(&cache->object_list_lock);
	refcount_set(&cache->unbind_pincount, 1);
	xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
	xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);

	/* set default caching limits
	 * - limit at 1% free space and/or free files
	 * - cull below 5% free space and/or free files
	 * - cease culling above 7% free space and/or free files
	 */
	cache->frun_percent = 7;
	cache->fcull_percent = 5;
	cache->fstop_percent = 1;
	cache->brun_percent = 7;
	cache->bcull_percent = 5;
	cache->bstop_percent = 1;

	file->private_data = cache;
	cache->cachefilesd = file;
	return 0;
}

void cachefiles_flush_reqs(struct cachefiles_cache *cache)
{
	struct xarray *xa = &cache->reqs;
	struct cachefiles_req *req;
	unsigned long index;

	/*
	 * Make sure the following two operations won't be reordered.
	 *   1) set CACHEFILES_DEAD bit
	 *   2) flush requests in the xarray
	 * Otherwise the request may be enqueued after xarray has been
	 * flushed, leaving the orphan request never being completed.
	 *
	 * CPU 1			CPU 2
	 * =====			=====
	 * flush requests in the xarray
	 *				test CACHEFILES_DEAD bit
	 *				enqueue the request
	 * set CACHEFILES_DEAD bit
	 */
	smp_mb();

	xa_lock(xa);
	xa_for_each(xa, index, req) {
		req->error = -EIO;
		complete(&req->done);
		__xa_erase(xa, index);
	}
	xa_unlock(xa);

	xa_destroy(&cache->reqs);
	xa_destroy(&cache->ondemand_ids);
}

void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
{
	if (refcount_dec_and_test(&cache->unbind_pincount)) {
		cachefiles_daemon_unbind(cache);
		cachefiles_open = 0;
		kfree(cache);
	}
}

void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
{
	refcount_inc(&cache->unbind_pincount);
}

/*
 * Release a cache.
 */
static int cachefiles_daemon_release(struct inode *inode, struct file *file)
{
	struct cachefiles_cache *cache = file->private_data;

	_enter("");

	ASSERT(cache);

	set_bit(CACHEFILES_DEAD, &cache->flags);

	if (cachefiles_in_ondemand_mode(cache))
		cachefiles_flush_reqs(cache);

	/* clean up the control file interface */
	cache->cachefilesd = NULL;
	file->private_data = NULL;

	cachefiles_put_unbind_pincount(cache);

	_leave("");
	return 0;
}

static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
					 char __user *_buffer, size_t buflen)
{
	unsigned long long b_released;
	unsigned f_released;
	char buffer[256];
	int n;

	/* check how much space the cache has */
	cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);

	/* summarise */
	f_released = atomic_xchg(&cache->f_released, 0);
	b_released = atomic_long_xchg(&cache->b_released, 0);
	clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);

	n = snprintf(buffer, sizeof(buffer),
		     "cull=%c"
		     " frun=%llx"
		     " fcull=%llx"
		     " fstop=%llx"
		     " brun=%llx"
		     " bcull=%llx"
		     " bstop=%llx"
		     " freleased=%x"
		     " breleased=%llx",
		     test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
		     (unsigned long long) cache->frun,
		     (unsigned long long) cache->fcull,
		     (unsigned long long) cache->fstop,
		     (unsigned long long) cache->brun,
		     (unsigned long long) cache->bcull,
		     (unsigned long long) cache->bstop,
		     f_released,
		     b_released);

	if (n > buflen)
		return -EMSGSIZE;

	if (copy_to_user(_buffer, buffer, n) != 0)
		return -EFAULT;

	return n;
}

/*
 * Read the cache state.
 */
static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
				      size_t buflen, loff_t *pos)
{
	struct cachefiles_cache *cache = file->private_data;

	//_enter(",,%zu,", buflen);

	if (!test_bit(CACHEFILES_READY, &cache->flags))
		return 0;

	if (cachefiles_in_ondemand_mode(cache))
		return cachefiles_ondemand_daemon_read(cache, _buffer, buflen);
	else
		return cachefiles_do_daemon_read(cache, _buffer, buflen);
}

/*
 * Take a command from cachefilesd, parse it and act on it.
 */
static ssize_t cachefiles_daemon_write(struct file *file,
				       const char __user *_data,
				       size_t datalen,
				       loff_t *pos)
{
	const struct cachefiles_daemon_cmd *cmd;
	struct cachefiles_cache *cache = file->private_data;
	ssize_t ret;
	char *data, *args, *cp;

	//_enter(",,%zu,", datalen);

	ASSERT(cache);

	if (test_bit(CACHEFILES_DEAD, &cache->flags))
		return -EIO;

	if (datalen > PAGE_SIZE - 1)
		return -EOPNOTSUPP;

	/* drag the command string into the kernel so we can parse it */
	data = memdup_user_nul(_data, datalen);
	if (IS_ERR(data))
		return PTR_ERR(data);

	ret = -EINVAL;
	if (memchr(data, '\0', datalen))
		goto error;

	/* strip any newline */
	cp = memchr(data, '\n', datalen);
	if (cp) {
		if (cp == data)
			goto error;

		*cp = '\0';
	}

	/* parse the command */
	ret = -EOPNOTSUPP;

	for (args = data; *args; args++)
		if (isspace(*args))
			break;
	if (*args) {
		if (args == data)
			goto error;
		*args = '\0';
		args = skip_spaces(++args);
	}

	/* run the appropriate command handler */
	for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
		if (strcmp(cmd->name, data) == 0)
			goto found_command;

error:
	kfree(data);
	//_leave(" = %zd", ret);
	return ret;

found_command:
	mutex_lock(&cache->daemon_mutex);

	ret = -EIO;
	if (!test_bit(CACHEFILES_DEAD, &cache->flags))
		ret = cmd->handler(cache, args);

	mutex_unlock(&cache->daemon_mutex);

	if (ret == 0)
		ret = datalen;
	goto error;
}

/*
 * Poll for culling state
 * - use EPOLLOUT to indicate culling state
 */
static __poll_t cachefiles_daemon_poll(struct file *file,
					   struct poll_table_struct *poll)
{
	struct cachefiles_cache *cache = file->private_data;
	XA_STATE(xas, &cache->reqs, 0);
	struct cachefiles_req *req;
	__poll_t mask;

	poll_wait(file, &cache->daemon_pollwq, poll);
	mask = 0;

	if (cachefiles_in_ondemand_mode(cache)) {
		if (!xa_empty(&cache->reqs)) {
			xas_lock(&xas);
			xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
				if (!cachefiles_ondemand_is_reopening_read(req)) {
					mask |= EPOLLIN;
					break;
				}
			}
			xas_unlock(&xas);
		}
	} else {
		if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
			mask |= EPOLLIN;
	}

	if (test_bit(CACHEFILES_CULLING, &cache->flags))
		mask |= EPOLLOUT;

	return mask;
}

/*
 * Give a range error for cache space constraints
 * - can be tail-called
 */
static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
					 char *args)
{
	pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");

	return -EINVAL;
}

/*
 * Set the percentage of files at which to stop culling
 * - command: "frun <N>%"
 */
static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
{
	unsigned long frun;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	frun = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (frun <= cache->fcull_percent || frun >= 100)
		return cachefiles_daemon_range_error(cache, args);

	cache->frun_percent = frun;
	return 0;
}

/*
 * Set the percentage of files at which to start culling
 * - command: "fcull <N>%"
 */
static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
{
	unsigned long fcull;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	fcull = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
		return cachefiles_daemon_range_error(cache, args);

	cache->fcull_percent = fcull;
	return 0;
}

/*
 * Set the percentage of files at which to stop allocating
 * - command: "fstop <N>%"
 */
static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
{
	unsigned long fstop;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	fstop = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (fstop >= cache->fcull_percent)
		return cachefiles_daemon_range_error(cache, args);

	cache->fstop_percent = fstop;
	return 0;
}

/*
 * Set the percentage of blocks at which to stop culling
 * - command: "brun <N>%"
 */
static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
{
	unsigned long brun;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	brun = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (brun <= cache->bcull_percent || brun >= 100)
		return cachefiles_daemon_range_error(cache, args);

	cache->brun_percent = brun;
	return 0;
}

/*
 * Set the percentage of blocks at which to start culling
 * - command: "bcull <N>%"
 */
static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
{
	unsigned long bcull;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	bcull = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
		return cachefiles_daemon_range_error(cache, args);

	cache->bcull_percent = bcull;
	return 0;
}

/*
 * Set the percentage of blocks at which to stop allocating
 * - command: "bstop <N>%"
 */
static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
{
	unsigned long bstop;

	_enter(",%s", args);

	if (!*args)
		return -EINVAL;

	bstop = simple_strtoul(args, &args, 10);
	if (args[0] != '%' || args[1] != '\0')
		return -EINVAL;

	if (bstop >= cache->bcull_percent)
		return cachefiles_daemon_range_error(cache, args);

	cache->bstop_percent = bstop;
	return 0;
}

/*
 * Set the cache directory
 * - command: "dir <name>"
 */
static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
{
	char *dir;

	_enter(",%s", args);

	if (!*args) {
		pr_err("Empty directory specified\n");
		return -EINVAL;
	}

	if (cache->rootdirname) {
		pr_err("Second cache directory specified\n");
		return -EEXIST;
	}

	dir = kstrdup(args, GFP_KERNEL);
	if (!dir)
		return -ENOMEM;

	cache->rootdirname = dir;
	return 0;
}

/*
 * Set the cache security context
 * - command: "secctx <ctx>"
 */
static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
{
	int err;

	_enter(",%s", args);

	if (!*args) {
		pr_err("Empty security context specified\n");
		return -EINVAL;
	}

	if (cache->have_secid) {
		pr_err("Second security context specified\n");
		return -EINVAL;
	}

	err = security_secctx_to_secid(args, strlen(args), &cache->secid);
	if (err)
		return err;

	cache->have_secid = true;
	return 0;
}

/*
 * Set the cache tag
 * - command: "tag <name>"
 */
static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
{
	char *tag;

	_enter(",%s", args);

	if (!*args) {
		pr_err("Empty tag specified\n");
		return -EINVAL;
	}

	if (cache->tag)
		return -EEXIST;

	tag = kstrdup(args, GFP_KERNEL);
	if (!tag)
		return -ENOMEM;

	cache->tag = tag;
	return 0;
}

/*
 * Request a node in the cache be culled from the current working directory
 * - command: "cull <name>"
 */
static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
{
	struct path path;
	const struct cred *saved_cred;
	int ret;

	_enter(",%s", args);

	if (strchr(args, '/'))
		goto inval;

	if (!test_bit(CACHEFILES_READY, &cache->flags)) {
		pr_err("cull applied to unready cache\n");
		return -EIO;
	}

	if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
		pr_err("cull applied to dead cache\n");
		return -EIO;
	}

	get_fs_pwd(current->fs, &path);

	if (!d_can_lookup(path.dentry))
		goto notdir;

	cachefiles_begin_secure(cache, &saved_cred);
	ret = cachefiles_cull(cache, path.dentry, args);
	cachefiles_end_secure(cache, saved_cred);

	path_put(&path);
	_leave(" = %d", ret);
	return ret;

notdir:
	path_put(&path);
	pr_err("cull command requires dirfd to be a directory\n");
	return -ENOTDIR;

inval:
	pr_err("cull command requires dirfd and filename\n");
	return -EINVAL;
}

/*
 * Set debugging mode
 * - command: "debug <mask>"
 */
static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
{
	unsigned long mask;

	_enter(",%s", args);

	mask = simple_strtoul(args, &args, 0);
	if (args[0] != '\0')
		goto inval;

	cachefiles_debug = mask;
	_leave(" = 0");
	return 0;

inval:
	pr_err("debug command requires mask\n");
	return -EINVAL;
}

/*
 * Find out whether an object in the current working directory is in use or not
 * - command: "inuse <name>"
 */
static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
{
	struct path path;
	const struct cred *saved_cred;
	int ret;

	//_enter(",%s", args);

	if (strchr(args, '/'))
		goto inval;

	if (!test_bit(CACHEFILES_READY, &cache->flags)) {
		pr_err("inuse applied to unready cache\n");
		return -EIO;
	}

	if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
		pr_err("inuse applied to dead cache\n");
		return -EIO;
	}

	get_fs_pwd(current->fs, &path);

	if (!d_can_lookup(path.dentry))
		goto notdir;

	cachefiles_begin_secure(cache, &saved_cred);
	ret = cachefiles_check_in_use(cache, path.dentry, args);
	cachefiles_end_secure(cache, saved_cred);

	path_put(&path);
	//_leave(" = %d", ret);
	return ret;

notdir:
	path_put(&path);
	pr_err("inuse command requires dirfd to be a directory\n");
	return -ENOTDIR;

inval:
	pr_err("inuse command requires dirfd and filename\n");
	return -EINVAL;
}

/*
 * Bind a directory as a cache
 */
static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
{
	_enter("{%u,%u,%u,%u,%u,%u},%s",
	       cache->frun_percent,
	       cache->fcull_percent,
	       cache->fstop_percent,
	       cache->brun_percent,
	       cache->bcull_percent,
	       cache->bstop_percent,
	       args);

	if (cache->fstop_percent >= cache->fcull_percent ||
	    cache->fcull_percent >= cache->frun_percent ||
	    cache->frun_percent  >= 100)
		return -ERANGE;

	if (cache->bstop_percent >= cache->bcull_percent ||
	    cache->bcull_percent >= cache->brun_percent ||
	    cache->brun_percent  >= 100)
		return -ERANGE;

	if (!cache->rootdirname) {
		pr_err("No cache directory specified\n");
		return -EINVAL;
	}

	/* Don't permit already bound caches to be re-bound */
	if (test_bit(CACHEFILES_READY, &cache->flags)) {
		pr_err("Cache already bound\n");
		return -EBUSY;
	}

	if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) {
		if (!strcmp(args, "ondemand")) {
			set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
		} else if (*args) {
			pr_err("Invalid argument to the 'bind' command\n");
			return -EINVAL;
		}
	} else if (*args) {
		pr_err("'bind' command doesn't take an argument\n");
		return -EINVAL;
	}

	/* Make sure we have copies of the tag string */
	if (!cache->tag) {
		/*
		 * The tag string is released by the fops->release()
		 * function, so we don't release it on error here
		 */
		cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
		if (!cache->tag)
			return -ENOMEM;
	}

	return cachefiles_add_cache(cache);
}

/*
 * Unbind a cache.
 */
static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
{
	_enter("");

	if (test_bit(CACHEFILES_READY, &cache->flags))
		cachefiles_withdraw_cache(cache);

	cachefiles_put_directory(cache->graveyard);
	cachefiles_put_directory(cache->store);
	mntput(cache->mnt);
	put_cred(cache->cache_cred);

	kfree(cache->rootdirname);
	kfree(cache->tag);

	_leave("");
}
Commit	Line	Data
	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
	25	static int cachefiles_daemon_open(struct inode , struct file );
	26	static int cachefiles_daemon_release(struct inode , struct file );
	27	static ssize_t cachefiles_daemon_read(struct file , char __user , size_t,
	28	loff_t *);
	29	static ssize_t cachefiles_daemon_write(struct file , const char __user ,
	30	size_t, loff_t *);
	31	static __poll_t cachefiles_daemon_poll(struct file *,
	32	struct poll_table_struct *);
	33	static int cachefiles_daemon_frun(struct cachefiles_cache , char );
	34	static int cachefiles_daemon_fcull(struct cachefiles_cache , char );
	35	static int cachefiles_daemon_fstop(struct cachefiles_cache , char );
	36	static int cachefiles_daemon_brun(struct cachefiles_cache , char );
	37	static int cachefiles_daemon_bcull(struct cachefiles_cache , char );
	38	static int cachefiles_daemon_bstop(struct cachefiles_cache , char );
	39	static int cachefiles_daemon_cull(struct cachefiles_cache , char );
	40	static int cachefiles_daemon_debug(struct cachefiles_cache , char );
	41	static int cachefiles_daemon_dir(struct cachefiles_cache , char );
	42	static int cachefiles_daemon_inuse(struct cachefiles_cache , char );
	43	static int cachefiles_daemon_secctx(struct cachefiles_cache , char );
	44	static int cachefiles_daemon_tag(struct cachefiles_cache , char );
	45	static int cachefiles_daemon_bind(struct cachefiles_cache , char );
	46	static void cachefiles_daemon_unbind(struct cachefiles_cache *);
	47
	48	static unsigned long cachefiles_open;
	49
	50	const 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
	60	struct cachefiles_daemon_cmd {
	61	char name[8];
	62	int (handler)(struct cachefiles_cache cache, char *args);
	63	};
	64
	65	static 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	*/
	90	static 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
	137	void 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
	171	void 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
	180	void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
	181	{
	182	refcount_inc(&cache->unbind_pincount);
	183	}
	184
	185	/*
	186	* Release a cache.
	187	*/
	188	static 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
	211	static 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	*/
	259	static 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	*/
	278	static 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
	334	error:
	335	kfree(data);
	336	//_leave(" = %zd", ret);
	337	return ret;
	338
	339	found_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	*/
	357	static __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	*/
	394	static 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	*/
	406	static 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	*/
	430	static 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	*/
	454	static 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	*/
	478	static 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	*/
	502	static 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	*/
	526	static 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	*/
	550	static 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	*/
	578	static 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	*/
	606	static 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	*/
	632	static 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
	666	notdir:
	667	path_put(&path);
	668	pr_err("cull command requires dirfd to be a directory\n");
	669	return -ENOTDIR;
	670
	671	inval:
	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	*/
	680	static 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
	694	inval:
	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	*/
	703	static 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
	737	notdir:
	738	path_put(&path);
	739	pr_err("inuse command requires dirfd to be a directory\n");
	740	return -ENOTDIR;
	741
	742	inval:
	743	pr_err("inuse command requires dirfd and filename\n");
	744	return -EINVAL;
	745	}
	746
	747	/*
	748	* Bind a directory as a cache
	749	*/
	750	static 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	*/
	811	static 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	}