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

/* Daemon interface
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#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/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 unsigned int 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 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		},
	{ "",		NULL				}
};


/*
 * do various checks
 */
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);
	cache->active_nodes = RB_ROOT;
	rwlock_init(&cache->active_lock);
	init_waitqueue_head(&cache->daemon_pollwq);

	/* 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;
}

/*
 * 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);

	cachefiles_daemon_unbind(cache);

	ASSERT(!cache->active_nodes.rb_node);

	/* clean up the control file interface */
	cache->cachefilesd = NULL;
	file->private_data = NULL;
	cachefiles_open = 0;

	kfree(cache);

	_leave("");
	return 0;
}

/*
 * 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;
	char buffer[256];
	int n;

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

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

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

	/* summarise */
	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",
		     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
		     );

	if (n > buflen)
		return -EMSGSIZE;

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

	return n;
}

/*
 * command the cache
 */
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 < 0 || 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 POLLOUT to indicate culling state
 */
static unsigned int cachefiles_daemon_poll(struct file *file,
					   struct poll_table_struct *poll)
{
	struct cachefiles_cache *cache = file->private_data;
	unsigned int mask;

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

	if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
		mask |= POLLIN;

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

	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 < 0 || 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 < 0 || 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)
{
	char *secctx;

	_enter(",%s", args);

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

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

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

	cache->secctx = secctx;
	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;
	}

	/* extract the directory dentry from the cwd */
	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;
	}

	/* extract the directory dentry from the cwd */
	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;
}

/*
 * see if we have space for a number of pages and/or a number of files in the
 * cache
 */
int cachefiles_has_space(struct cachefiles_cache *cache,
			 unsigned fnr, unsigned bnr)
{
	struct kstatfs stats;
	struct path path = {
		.mnt	= cache->mnt,
		.dentry	= cache->mnt->mnt_root,
	};
	int ret;

	//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
	//       (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,
	//       fnr, bnr);

	/* find out how many pages of blockdev are available */
	memset(&stats, 0, sizeof(stats));

	ret = vfs_statfs(&path, &stats);
	if (ret < 0) {
		if (ret == -EIO)
			cachefiles_io_error(cache, "statfs failed");
		_leave(" = %d", ret);
		return ret;
	}

	stats.f_bavail >>= cache->bshift;

	//_debug("avail %llu,%llu",
	//       (unsigned long long) stats.f_ffree,
	//       (unsigned long long) stats.f_bavail);

	/* see if there is sufficient space */
	if (stats.f_ffree > fnr)
		stats.f_ffree -= fnr;
	else
		stats.f_ffree = 0;

	if (stats.f_bavail > bnr)
		stats.f_bavail -= bnr;
	else
		stats.f_bavail = 0;

	ret = -ENOBUFS;
	if (stats.f_ffree < cache->fstop ||
	    stats.f_bavail < cache->bstop)
		goto begin_cull;

	ret = 0;
	if (stats.f_ffree < cache->fcull ||
	    stats.f_bavail < cache->bcull)
		goto begin_cull;

	if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
	    stats.f_ffree >= cache->frun &&
	    stats.f_bavail >= cache->brun &&
	    test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
	    ) {
		_debug("cease culling");
		cachefiles_state_changed(cache);
	}

	//_leave(" = 0");
	return 0;

begin_cull:
	if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
		_debug("### CULL CACHE ###");
		cachefiles_state_changed(cache);
	}

	_leave(" = %d", ret);
	return ret;
}
Commit	Line	Data
9ae326a6 DH	1	/* Daemon interface
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14	#include <linux/sched.h>
	15	#include <linux/completion.h>
	16	#include <linux/slab.h>
	17	#include <linux/fs.h>
	18	#include <linux/file.h>
	19	#include <linux/namei.h>
	20	#include <linux/poll.h>
	21	#include <linux/mount.h>
	22	#include <linux/statfs.h>
	23	#include <linux/ctype.h>
e7d2860b	24	#include <linux/string.h>
9ae326a6 DH	25	#include <linux/fs_struct.h>
	26	#include "internal.h"
	27
	28	static int cachefiles_daemon_open(struct inode , struct file );
	29	static int cachefiles_daemon_release(struct inode , struct file );
	30	static ssize_t cachefiles_daemon_read(struct file , char __user , size_t,
	31	loff_t *);
	32	static ssize_t cachefiles_daemon_write(struct file , const char __user ,
	33	size_t, loff_t *);
	34	static unsigned int cachefiles_daemon_poll(struct file *,
	35	struct poll_table_struct *);
	36	static int cachefiles_daemon_frun(struct cachefiles_cache , char );
	37	static int cachefiles_daemon_fcull(struct cachefiles_cache , char );
	38	static int cachefiles_daemon_fstop(struct cachefiles_cache , char );
	39	static int cachefiles_daemon_brun(struct cachefiles_cache , char );
	40	static int cachefiles_daemon_bcull(struct cachefiles_cache , char );
	41	static int cachefiles_daemon_bstop(struct cachefiles_cache , char );
	42	static int cachefiles_daemon_cull(struct cachefiles_cache , char );
	43	static int cachefiles_daemon_debug(struct cachefiles_cache , char );
	44	static int cachefiles_daemon_dir(struct cachefiles_cache , char );
	45	static int cachefiles_daemon_inuse(struct cachefiles_cache , char );
	46	static int cachefiles_daemon_secctx(struct cachefiles_cache , char );
	47	static int cachefiles_daemon_tag(struct cachefiles_cache , char );
	48
	49	static unsigned long cachefiles_open;
	50
	51	const struct file_operations cachefiles_daemon_fops = {
	52	.owner = THIS_MODULE,
	53	.open = cachefiles_daemon_open,
	54	.release = cachefiles_daemon_release,
	55	.read = cachefiles_daemon_read,
	56	.write = cachefiles_daemon_write,
	57	.poll = cachefiles_daemon_poll,
6038f373	58	.llseek = noop_llseek,
9ae326a6 DH	59	};
	60
	61	struct cachefiles_daemon_cmd {
	62	char name[8];
	63	int (handler)(struct cachefiles_cache cache, char *args);
	64	};
	65
	66	static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
	67	{ "bind", cachefiles_daemon_bind },
	68	{ "brun", cachefiles_daemon_brun },
	69	{ "bcull", cachefiles_daemon_bcull },
	70	{ "bstop", cachefiles_daemon_bstop },
	71	{ "cull", cachefiles_daemon_cull },
	72	{ "debug", cachefiles_daemon_debug },
	73	{ "dir", cachefiles_daemon_dir },
	74	{ "frun", cachefiles_daemon_frun },
	75	{ "fcull", cachefiles_daemon_fcull },
	76	{ "fstop", cachefiles_daemon_fstop },
	77	{ "inuse", cachefiles_daemon_inuse },
	78	{ "secctx", cachefiles_daemon_secctx },
	79	{ "tag", cachefiles_daemon_tag },
	80	{ "", NULL }
	81	};
	82
	83
	84	/*
	85	* do various checks
	86	*/
	87	static int cachefiles_daemon_open(struct inode inode, struct file file)
	88	{
	89	struct cachefiles_cache *cache;
	90
	91	_enter("");
	92
	93	/* only the superuser may do this */
	94	if (!capable(CAP_SYS_ADMIN))
	95	return -EPERM;
	96
	97	/* the cachefiles device may only be open once at a time */
	98	if (xchg(&cachefiles_open, 1) == 1)
	99	return -EBUSY;
	100
	101	/* allocate a cache record */
	102	cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
	103	if (!cache) {
	104	cachefiles_open = 0;
	105	return -ENOMEM;
	106	}
	107
	108	mutex_init(&cache->daemon_mutex);
	109	cache->active_nodes = RB_ROOT;
	110	rwlock_init(&cache->active_lock);
	111	init_waitqueue_head(&cache->daemon_pollwq);
	112
	113	/* set default caching limits
	114	* - limit at 1% free space and/or free files
	115	* - cull below 5% free space and/or free files
	116	* - cease culling above 7% free space and/or free files
	117	*/
	118	cache->frun_percent = 7;
	119	cache->fcull_percent = 5;
	120	cache->fstop_percent = 1;
	121	cache->brun_percent = 7;
	122	cache->bcull_percent = 5;
123	cache->bstop_percent = 1;
124
125	file->private_data = cache;
126	cache->cachefilesd = file;
127	return 0;
128	}
129
130	/*
131	* release a cache
132	*/
133	static int cachefiles_daemon_release(struct inode inode, struct file file)
134	{
135	struct cachefiles_cache *cache = file->private_data;
136
137	_enter("");
138
139	ASSERT(cache);
140
141	set_bit(CACHEFILES_DEAD, &cache->flags);
142
143	cachefiles_daemon_unbind(cache);
144
145	ASSERT(!cache->active_nodes.rb_node);
146
147	/* clean up the control file interface */
148	cache->cachefilesd = NULL;
149	file->private_data = NULL;
150	cachefiles_open = 0;
151
152	kfree(cache);
153
154	_leave("");
155	return 0;
156	}
157
158	/*
159	* read the cache state
160	*/
161	static ssize_t cachefiles_daemon_read(struct file file, char __user _buffer,
162	size_t buflen, loff_t *pos)
163	{
164	struct cachefiles_cache *cache = file->private_data;
165	char buffer[256];
166	int n;
167
168	//_enter(",,%zu,", buflen);
169
170	if (!test_bit(CACHEFILES_READY, &cache->flags))
171	return 0;
172
173	/* check how much space the cache has */
174	cachefiles_has_space(cache, 0, 0);
175
176	/* summarise */
177	clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
178
179	n = snprintf(buffer, sizeof(buffer),
180	"cull=%c"
181	" frun=%llx"
182	" fcull=%llx"
183	" fstop=%llx"
184	" brun=%llx"
185	" bcull=%llx"
186	" bstop=%llx",
187	test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
188	(unsigned long long) cache->frun,
189	(unsigned long long) cache->fcull,
190	(unsigned long long) cache->fstop,
191	(unsigned long long) cache->brun,
192	(unsigned long long) cache->bcull,
193	(unsigned long long) cache->bstop
194	);
195
196	if (n > buflen)
197	return -EMSGSIZE;
198
199	if (copy_to_user(_buffer, buffer, n) != 0)
200	return -EFAULT;
201
202	return n;
203	}
204
205	/*
206	* command the cache
207	*/
208	static ssize_t cachefiles_daemon_write(struct file *file,
209	const char __user *_data,
210	size_t datalen,
211	loff_t *pos)
212	{
213	const struct cachefiles_daemon_cmd *cmd;
214	struct cachefiles_cache *cache = file->private_data;
215	ssize_t ret;
216	char data, args, *cp;
217
218	//_enter(",,%zu,", datalen);
219
220	ASSERT(cache);
221
222	if (test_bit(CACHEFILES_DEAD, &cache->flags))
223	return -EIO;
224
225	if (datalen < 0 \|\| datalen > PAGE_SIZE - 1)
226	return -EOPNOTSUPP;
227
228	/* drag the command string into the kernel so we can parse it */
16e5c1fc AV	229	data = memdup_user_nul(_data, datalen);
	230	if (IS_ERR(data))
	231	return PTR_ERR(data);
9ae326a6 DH	232
	233	ret = -EINVAL;
	234	if (memchr(data, '\0', datalen))
	235	goto error;
	236
	237	/* strip any newline */
	238	cp = memchr(data, '\n', datalen);
	239	if (cp) {
	240	if (cp == data)
	241	goto error;
	242
	243	*cp = '\0';
	244	}
	245
	246	/* parse the command */
	247	ret = -EOPNOTSUPP;
	248
	249	for (args = data; *args; args++)
	250	if (isspace(*args))
	251	break;
	252	if (*args) {
	253	if (args == data)
	254	goto error;
	255	*args = '\0';
e7d2860b	256	args = skip_spaces(++args);
9ae326a6 DH	257	}
	258
	259	/* run the appropriate command handler */
	260	for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
	261	if (strcmp(cmd->name, data) == 0)
	262	goto found_command;
	263
	264	error:
	265	kfree(data);
	266	//_leave(" = %zd", ret);
	267	return ret;
	268
	269	found_command:
	270	mutex_lock(&cache->daemon_mutex);
	271
	272	ret = -EIO;
	273	if (!test_bit(CACHEFILES_DEAD, &cache->flags))
	274	ret = cmd->handler(cache, args);
	275
	276	mutex_unlock(&cache->daemon_mutex);
	277
	278	if (ret == 0)
	279	ret = datalen;
	280	goto error;
	281	}
	282
	283	/*
	284	* poll for culling state
	285	* - use POLLOUT to indicate culling state
	286	*/
	287	static unsigned int cachefiles_daemon_poll(struct file *file,
	288	struct poll_table_struct *poll)
	289	{
	290	struct cachefiles_cache *cache = file->private_data;
	291	unsigned int mask;
	292
	293	poll_wait(file, &cache->daemon_pollwq, poll);
	294	mask = 0;
	295
	296	if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
	297	mask \|= POLLIN;
	298
	299	if (test_bit(CACHEFILES_CULLING, &cache->flags))
	300	mask \|= POLLOUT;
	301
	302	return mask;
	303	}
	304
	305	/*
	306	* give a range error for cache space constraints
	307	* - can be tail-called
	308	*/
	309	static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
	310	char *args)
	311	{
6ff66ac7	312	pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
9ae326a6 DH	313
	314	return -EINVAL;
	315	}
	316
	317	/*
	318	* set the percentage of files at which to stop culling
	319	* - command: "frun <N>%"
	320	*/
	321	static int cachefiles_daemon_frun(struct cachefiles_cache cache, char args)
	322	{
	323	unsigned long frun;
	324
	325	_enter(",%s", args);
	326
	327	if (!*args)
	328	return -EINVAL;
	329
	330	frun = simple_strtoul(args, &args, 10);
	331	if (args[0] != '%' \|\| args[1] != '\0')
	332	return -EINVAL;
	333
	334	if (frun <= cache->fcull_percent \|\| frun >= 100)
	335	return cachefiles_daemon_range_error(cache, args);
	336
	337	cache->frun_percent = frun;
	338	return 0;
	339	}
	340
	341	/*
	342	* set the percentage of files at which to start culling
	343	* - command: "fcull <N>%"
	344	*/
	345	static int cachefiles_daemon_fcull(struct cachefiles_cache cache, char args)
	346	{
	347	unsigned long fcull;
	348
	349	_enter(",%s", args);
	350
	351	if (!*args)
	352	return -EINVAL;
	353
	354	fcull = simple_strtoul(args, &args, 10);
	355	if (args[0] != '%' \|\| args[1] != '\0')
	356	return -EINVAL;
	357
	358	if (fcull <= cache->fstop_percent \|\| fcull >= cache->frun_percent)
	359	return cachefiles_daemon_range_error(cache, args);
	360
	361	cache->fcull_percent = fcull;
	362	return 0;
	363	}
	364
	365	/*
	366	* set the percentage of files at which to stop allocating
	367	* - command: "fstop <N>%"
	368	*/
	369	static int cachefiles_daemon_fstop(struct cachefiles_cache cache, char args)
	370	{
	371	unsigned long fstop;
	372
	373	_enter(",%s", args);
	374
	375	if (!*args)
	376	return -EINVAL;
377
378	fstop = simple_strtoul(args, &args, 10);
379	if (args[0] != '%' \|\| args[1] != '\0')
380	return -EINVAL;
381
382	if (fstop < 0 \|\| fstop >= cache->fcull_percent)
383	return cachefiles_daemon_range_error(cache, args);
384
385	cache->fstop_percent = fstop;
386	return 0;
387	}
388
389	/*
390	* set the percentage of blocks at which to stop culling
391	* - command: "brun <N>%"
392	*/
393	static int cachefiles_daemon_brun(struct cachefiles_cache cache, char args)
394	{
395	unsigned long brun;
396
397	_enter(",%s", args);
398
399	if (!*args)
400	return -EINVAL;
401
402	brun = simple_strtoul(args, &args, 10);
403	if (args[0] != '%' \|\| args[1] != '\0')
404	return -EINVAL;
405
406	if (brun <= cache->bcull_percent \|\| brun >= 100)
407	return cachefiles_daemon_range_error(cache, args);
408
409	cache->brun_percent = brun;
410	return 0;
411	}
412
413	/*
414	* set the percentage of blocks at which to start culling
415	* - command: "bcull <N>%"
416	*/
417	static int cachefiles_daemon_bcull(struct cachefiles_cache cache, char args)
418	{
419	unsigned long bcull;
420
421	_enter(",%s", args);
422
423	if (!*args)
424	return -EINVAL;
425
426	bcull = simple_strtoul(args, &args, 10);
427	if (args[0] != '%' \|\| args[1] != '\0')
428	return -EINVAL;
429
430	if (bcull <= cache->bstop_percent \|\| bcull >= cache->brun_percent)
431	return cachefiles_daemon_range_error(cache, args);
432
433	cache->bcull_percent = bcull;
434	return 0;
435	}
436
437	/*
438	* set the percentage of blocks at which to stop allocating
439	* - command: "bstop <N>%"
440	*/
441	static int cachefiles_daemon_bstop(struct cachefiles_cache cache, char args)
442	{
443	unsigned long bstop;
444
445	_enter(",%s", args);
446
447	if (!*args)
448	return -EINVAL;
449
450	bstop = simple_strtoul(args, &args, 10);
451	if (args[0] != '%' \|\| args[1] != '\0')
452	return -EINVAL;
453
454	if (bstop < 0 \|\| bstop >= cache->bcull_percent)
455	return cachefiles_daemon_range_error(cache, args);
456
457	cache->bstop_percent = bstop;
458	return 0;
459	}
460
461	/*
462	* set the cache directory
463	* - command: "dir <name>"
464	*/
465	static int cachefiles_daemon_dir(struct cachefiles_cache cache, char args)
466	{
467	char *dir;
468
469	_enter(",%s", args);
470
471	if (!*args) {
6ff66ac7	472	pr_err("Empty directory specified\n");
9ae326a6 DH	473	return -EINVAL;
	474	}
	475
	476	if (cache->rootdirname) {
6ff66ac7	477	pr_err("Second cache directory specified\n");
9ae326a6 DH	478	return -EEXIST;
	479	}
	480
	481	dir = kstrdup(args, GFP_KERNEL);
	482	if (!dir)
	483	return -ENOMEM;
	484
	485	cache->rootdirname = dir;
	486	return 0;
	487	}
	488
	489	/*
	490	* set the cache security context
	491	* - command: "secctx <ctx>"
	492	*/
	493	static int cachefiles_daemon_secctx(struct cachefiles_cache cache, char args)
	494	{
	495	char *secctx;
	496
	497	_enter(",%s", args);
	498
	499	if (!*args) {
6ff66ac7	500	pr_err("Empty security context specified\n");
9ae326a6 DH	501	return -EINVAL;
	502	}
	503
	504	if (cache->secctx) {
6ff66ac7	505	pr_err("Second security context specified\n");
9ae326a6 DH	506	return -EINVAL;
	507	}
	508
	509	secctx = kstrdup(args, GFP_KERNEL);
	510	if (!secctx)
	511	return -ENOMEM;
	512
	513	cache->secctx = secctx;
	514	return 0;
	515	}
	516
	517	/*
	518	* set the cache tag
	519	* - command: "tag <name>"
	520	*/
	521	static int cachefiles_daemon_tag(struct cachefiles_cache cache, char args)
	522	{
	523	char *tag;
	524
	525	_enter(",%s", args);
	526
	527	if (!*args) {
6ff66ac7	528	pr_err("Empty tag specified\n");
9ae326a6 DH	529	return -EINVAL;
	530	}
	531
	532	if (cache->tag)
	533	return -EEXIST;
	534
	535	tag = kstrdup(args, GFP_KERNEL);
	536	if (!tag)
	537	return -ENOMEM;
	538
	539	cache->tag = tag;
	540	return 0;
	541	}
	542
	543	/*
	544	* request a node in the cache be culled from the current working directory
	545	* - command: "cull <name>"
	546	*/
	547	static int cachefiles_daemon_cull(struct cachefiles_cache cache, char args)
	548	{
542ce7a9	549	struct path path;
9ae326a6 DH	550	const struct cred *saved_cred;
	551	int ret;
	552
	553	_enter(",%s", args);
	554
	555	if (strchr(args, '/'))
	556	goto inval;
	557
	558	if (!test_bit(CACHEFILES_READY, &cache->flags)) {
6ff66ac7	559	pr_err("cull applied to unready cache\n");
9ae326a6 DH	560	return -EIO;
	561	}
	562
	563	if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
6ff66ac7	564	pr_err("cull applied to dead cache\n");
9ae326a6 DH	565	return -EIO;
	566	}
	567
	568	/* extract the directory dentry from the cwd */
f7ad3c6b	569	get_fs_pwd(current->fs, &path);
9ae326a6	570
ce40fa78	571	if (!d_can_lookup(path.dentry))
9ae326a6 DH	572	goto notdir;
	573
	574	cachefiles_begin_secure(cache, &saved_cred);
542ce7a9	575	ret = cachefiles_cull(cache, path.dentry, args);
9ae326a6 DH	576	cachefiles_end_secure(cache, saved_cred);
9ae326a6 DH	577
542ce7a9	578	path_put(&path);
9ae326a6 DH	579	_leave(" = %d", ret);
	580	return ret;
	581
	582	notdir:
542ce7a9	583	path_put(&path);
6ff66ac7	584	pr_err("cull command requires dirfd to be a directory\n");
9ae326a6 DH	585	return -ENOTDIR;
	586
	587	inval:
6ff66ac7	588	pr_err("cull command requires dirfd and filename\n");
9ae326a6 DH	589	return -EINVAL;
	590	}
	591
	592	/*
	593	* set debugging mode
	594	* - command: "debug <mask>"
	595	*/
	596	static int cachefiles_daemon_debug(struct cachefiles_cache cache, char args)
	597	{
	598	unsigned long mask;
	599
	600	_enter(",%s", args);
	601
	602	mask = simple_strtoul(args, &args, 0);
	603	if (args[0] != '\0')
	604	goto inval;
	605
	606	cachefiles_debug = mask;
	607	_leave(" = 0");
	608	return 0;
	609
	610	inval:
6ff66ac7	611	pr_err("debug command requires mask\n");
9ae326a6 DH	612	return -EINVAL;
	613	}
	614
	615	/*
	616	* find out whether an object in the current working directory is in use or not
	617	* - command: "inuse <name>"
	618	*/
	619	static int cachefiles_daemon_inuse(struct cachefiles_cache cache, char args)
	620	{
542ce7a9	621	struct path path;
9ae326a6 DH	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)) {
6ff66ac7	631	pr_err("inuse applied to unready cache\n");
9ae326a6 DH	632	return -EIO;
	633	}
	634
	635	if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
6ff66ac7	636	pr_err("inuse applied to dead cache\n");
9ae326a6 DH	637	return -EIO;
	638	}
	639
	640	/* extract the directory dentry from the cwd */
f7ad3c6b	641	get_fs_pwd(current->fs, &path);
9ae326a6	642
ce40fa78	643	if (!d_can_lookup(path.dentry))
9ae326a6 DH	644	goto notdir;
	645
	646	cachefiles_begin_secure(cache, &saved_cred);
542ce7a9	647	ret = cachefiles_check_in_use(cache, path.dentry, args);
9ae326a6 DH	648	cachefiles_end_secure(cache, saved_cred);
9ae326a6 DH	649
542ce7a9	650	path_put(&path);
9ae326a6 DH	651	//_leave(" = %d", ret);
	652	return ret;
	653
	654	notdir:
542ce7a9	655	path_put(&path);
6ff66ac7	656	pr_err("inuse command requires dirfd to be a directory\n");
9ae326a6 DH	657	return -ENOTDIR;
	658
	659	inval:
6ff66ac7	660	pr_err("inuse command requires dirfd and filename\n");
9ae326a6 DH	661	return -EINVAL;
	662	}
	663
	664	/*
	665	* see if we have space for a number of pages and/or a number of files in the
	666	* cache
	667	*/
	668	int cachefiles_has_space(struct cachefiles_cache *cache,
	669	unsigned fnr, unsigned bnr)
	670	{
	671	struct kstatfs stats;
ebabe9a9 CH	672	struct path path = {
	673	.mnt = cache->mnt,
	674	.dentry = cache->mnt->mnt_root,
	675	};
9ae326a6 DH	676	int ret;
	677
	678	//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
	679	// (unsigned long long) cache->frun,
	680	// (unsigned long long) cache->fcull,
	681	// (unsigned long long) cache->fstop,
	682	// (unsigned long long) cache->brun,
	683	// (unsigned long long) cache->bcull,
	684	// (unsigned long long) cache->bstop,
	685	// fnr, bnr);
	686
	687	/* find out how many pages of blockdev are available */
	688	memset(&stats, 0, sizeof(stats));
	689
ebabe9a9	690	ret = vfs_statfs(&path, &stats);
9ae326a6 DH	691	if (ret < 0) {
	692	if (ret == -EIO)
	693	cachefiles_io_error(cache, "statfs failed");
	694	_leave(" = %d", ret);
	695	return ret;
	696	}
	697
	698	stats.f_bavail >>= cache->bshift;
	699
	700	//_debug("avail %llu,%llu",
	701	// (unsigned long long) stats.f_ffree,
	702	// (unsigned long long) stats.f_bavail);
	703
	704	/* see if there is sufficient space */
	705	if (stats.f_ffree > fnr)
	706	stats.f_ffree -= fnr;
	707	else
	708	stats.f_ffree = 0;
	709
	710	if (stats.f_bavail > bnr)
	711	stats.f_bavail -= bnr;
	712	else
	713	stats.f_bavail = 0;
	714
	715	ret = -ENOBUFS;
	716	if (stats.f_ffree < cache->fstop \|\|
	717	stats.f_bavail < cache->bstop)
	718	goto begin_cull;
	719
	720	ret = 0;
	721	if (stats.f_ffree < cache->fcull \|\|
	722	stats.f_bavail < cache->bcull)
	723	goto begin_cull;
	724
	725	if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
	726	stats.f_ffree >= cache->frun &&
	727	stats.f_bavail >= cache->brun &&
	728	test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
	729	) {
	730	_debug("cease culling");
	731	cachefiles_state_changed(cache);
	732	}
	733
	734	//_leave(" = 0");
	735	return 0;
	736
	737	begin_cull:
	738	if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
	739	_debug("### CULL CACHE ###");
	740	cachefiles_state_changed(cache);
	741	}
	742
	743	_leave(" = %d", ret);
	744	return ret;
	745	}