cachefiles: Delete the cachefiles driver pending rewrite

Delete the code from the cachefiles driver to make it easier to rewrite and
resubmit in a logical manner.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819577641.215744.12718114397770666596.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906883770.143852.4149714614981373410.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967076066.1823006.7175712134577687753.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021483619.640689.7586546280515844702.stgit@warthog.procyon.org.uk/ # v4

1 files changed, 0 insertions, 748 deletions

diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
deleted file mode 100644
index 752c1e43416f..000000000000
--- a/fs/cachefiles/daemon.c
+++ /dev/null
@@ -1,748 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* Daemon interface
- *
- * Copyright (C) 2007 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/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 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;
-	unsigned long long b_released;
-	unsigned f_released;
-	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 */
-	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;
-}
-
-/*
- * 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 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;
-	__poll_t mask;
-
-	poll_wait(file, &cache->daemon_pollwq, poll);
-	mask = 0;
-
-	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 < 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;
-}