linux/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 ([email protected])
 */

#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 __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 = …;

struct cachefiles_daemon_cmd { … };

static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = …;


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

void cachefiles_flush_reqs(struct cachefiles_cache *cache)
{ … }

void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
{ … }

void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
{ … }

/*
 * Release a cache.
 */
static int cachefiles_daemon_release(struct inode *inode, struct file *file)
{ … }

static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
					 char __user *_buffer, size_t buflen)
{ … }

/*
 * Read the cache state.
 */
static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
				      size_t buflen, loff_t *pos)
{ … }

/*
 * 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)
{ … }

/*
 * Poll for culling state
 * - use EPOLLOUT to indicate culling state
 */
static __poll_t cachefiles_daemon_poll(struct file *file,
					   struct poll_table_struct *poll)
{ … }

/*
 * Give a range error for cache space constraints
 * - can be tail-called
 */
static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
					 char *args)
{ … }

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

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

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

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

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

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

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

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

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

/*
 * 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)
{ … }

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

/*
 * 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)
{ … }

/*
 * Bind a directory as a cache
 */
static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
{ … }

/*
 * Unbind a cache.
 */
static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
{ … }