3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
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>
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>
24 #include <linux/string.h>
25 #include <linux/fs_struct.h>
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,
32 static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
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 *);
49 static unsigned long cachefiles_open;
51 const struct file_operations cachefiles_daemon_fops = {
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,
58 .llseek = noop_llseek,
61 struct cachefiles_daemon_cmd {
63 int (*handler)(struct cachefiles_cache *cache, char *args);
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 },
87 static int cachefiles_daemon_open(struct inode *inode, struct file *file)
89 struct cachefiles_cache *cache;
93 /* only the superuser may do this */
94 if (!capable(CAP_SYS_ADMIN))
97 /* the cachefiles device may only be open once at a time */
98 if (xchg(&cachefiles_open, 1) == 1)
101 /* allocate a cache record */
102 cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
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);
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
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;
125 file->private_data = cache;
126 cache->cachefilesd = file;
133 static int cachefiles_daemon_release(struct inode *inode, struct file *file)
135 struct cachefiles_cache *cache = file->private_data;
141 set_bit(CACHEFILES_DEAD, &cache->flags);
143 cachefiles_daemon_unbind(cache);
145 ASSERT(!cache->active_nodes.rb_node);
147 /* clean up the control file interface */
148 cache->cachefilesd = NULL;
149 file->private_data = NULL;
159 * read the cache state
161 static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
162 size_t buflen, loff_t *pos)
164 struct cachefiles_cache *cache = file->private_data;
168 //_enter(",,%zu,", buflen);
170 if (!test_bit(CACHEFILES_READY, &cache->flags))
173 /* check how much space the cache has */
174 cachefiles_has_space(cache, 0, 0);
177 clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
179 n = snprintf(buffer, sizeof(buffer),
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
199 if (copy_to_user(_buffer, buffer, n) != 0)
208 static ssize_t cachefiles_daemon_write(struct file *file,
209 const char __user *_data,
213 const struct cachefiles_daemon_cmd *cmd;
214 struct cachefiles_cache *cache = file->private_data;
216 char *data, *args, *cp;
218 //_enter(",,%zu,", datalen);
222 if (test_bit(CACHEFILES_DEAD, &cache->flags))
225 if (datalen < 0 || datalen > PAGE_SIZE - 1)
228 /* drag the command string into the kernel so we can parse it */
229 data = memdup_user_nul(_data, datalen);
231 return PTR_ERR(data);
234 if (memchr(data, '\0', datalen))
237 /* strip any newline */
238 cp = memchr(data, '\n', datalen);
246 /* parse the command */
249 for (args = data; *args; args++)
256 args = skip_spaces(++args);
259 /* run the appropriate command handler */
260 for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
261 if (strcmp(cmd->name, data) == 0)
266 //_leave(" = %zd", ret);
270 mutex_lock(&cache->daemon_mutex);
273 if (!test_bit(CACHEFILES_DEAD, &cache->flags))
274 ret = cmd->handler(cache, args);
276 mutex_unlock(&cache->daemon_mutex);
284 * poll for culling state
285 * - use POLLOUT to indicate culling state
287 static unsigned int cachefiles_daemon_poll(struct file *file,
288 struct poll_table_struct *poll)
290 struct cachefiles_cache *cache = file->private_data;
293 poll_wait(file, &cache->daemon_pollwq, poll);
296 if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
299 if (test_bit(CACHEFILES_CULLING, &cache->flags))
306 * give a range error for cache space constraints
307 * - can be tail-called
309 static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
312 pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
318 * set the percentage of files at which to stop culling
319 * - command: "frun <N>%"
321 static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
330 frun = simple_strtoul(args, &args, 10);
331 if (args[0] != '%' || args[1] != '\0')
334 if (frun <= cache->fcull_percent || frun >= 100)
335 return cachefiles_daemon_range_error(cache, args);
337 cache->frun_percent = frun;
342 * set the percentage of files at which to start culling
343 * - command: "fcull <N>%"
345 static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
354 fcull = simple_strtoul(args, &args, 10);
355 if (args[0] != '%' || args[1] != '\0')
358 if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
359 return cachefiles_daemon_range_error(cache, args);
361 cache->fcull_percent = fcull;
366 * set the percentage of files at which to stop allocating
367 * - command: "fstop <N>%"
369 static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
378 fstop = simple_strtoul(args, &args, 10);
379 if (args[0] != '%' || args[1] != '\0')
382 if (fstop < 0 || fstop >= cache->fcull_percent)
383 return cachefiles_daemon_range_error(cache, args);
385 cache->fstop_percent = fstop;
390 * set the percentage of blocks at which to stop culling
391 * - command: "brun <N>%"
393 static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
402 brun = simple_strtoul(args, &args, 10);
403 if (args[0] != '%' || args[1] != '\0')
406 if (brun <= cache->bcull_percent || brun >= 100)
407 return cachefiles_daemon_range_error(cache, args);
409 cache->brun_percent = brun;
414 * set the percentage of blocks at which to start culling
415 * - command: "bcull <N>%"
417 static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
426 bcull = simple_strtoul(args, &args, 10);
427 if (args[0] != '%' || args[1] != '\0')
430 if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
431 return cachefiles_daemon_range_error(cache, args);
433 cache->bcull_percent = bcull;
438 * set the percentage of blocks at which to stop allocating
439 * - command: "bstop <N>%"
441 static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
450 bstop = simple_strtoul(args, &args, 10);
451 if (args[0] != '%' || args[1] != '\0')
454 if (bstop < 0 || bstop >= cache->bcull_percent)
455 return cachefiles_daemon_range_error(cache, args);
457 cache->bstop_percent = bstop;
462 * set the cache directory
463 * - command: "dir <name>"
465 static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
472 pr_err("Empty directory specified\n");
476 if (cache->rootdirname) {
477 pr_err("Second cache directory specified\n");
481 dir = kstrdup(args, GFP_KERNEL);
485 cache->rootdirname = dir;
490 * set the cache security context
491 * - command: "secctx <ctx>"
493 static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
500 pr_err("Empty security context specified\n");
505 pr_err("Second security context specified\n");
509 secctx = kstrdup(args, GFP_KERNEL);
513 cache->secctx = secctx;
519 * - command: "tag <name>"
521 static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
528 pr_err("Empty tag specified\n");
535 tag = kstrdup(args, GFP_KERNEL);
544 * request a node in the cache be culled from the current working directory
545 * - command: "cull <name>"
547 static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
550 const struct cred *saved_cred;
555 if (strchr(args, '/'))
558 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
559 pr_err("cull applied to unready cache\n");
563 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
564 pr_err("cull applied to dead cache\n");
568 /* extract the directory dentry from the cwd */
569 get_fs_pwd(current->fs, &path);
571 if (!d_can_lookup(path.dentry))
574 cachefiles_begin_secure(cache, &saved_cred);
575 ret = cachefiles_cull(cache, path.dentry, args);
576 cachefiles_end_secure(cache, saved_cred);
579 _leave(" = %d", ret);
584 pr_err("cull command requires dirfd to be a directory\n");
588 pr_err("cull command requires dirfd and filename\n");
594 * - command: "debug <mask>"
596 static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
602 mask = simple_strtoul(args, &args, 0);
606 cachefiles_debug = mask;
611 pr_err("debug command requires mask\n");
616 * find out whether an object in the current working directory is in use or not
617 * - command: "inuse <name>"
619 static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
622 const struct cred *saved_cred;
625 //_enter(",%s", args);
627 if (strchr(args, '/'))
630 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
631 pr_err("inuse applied to unready cache\n");
635 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
636 pr_err("inuse applied to dead cache\n");
640 /* extract the directory dentry from the cwd */
641 get_fs_pwd(current->fs, &path);
643 if (!d_can_lookup(path.dentry))
646 cachefiles_begin_secure(cache, &saved_cred);
647 ret = cachefiles_check_in_use(cache, path.dentry, args);
648 cachefiles_end_secure(cache, saved_cred);
651 //_leave(" = %d", ret);
656 pr_err("inuse command requires dirfd to be a directory\n");
660 pr_err("inuse command requires dirfd and filename\n");
665 * see if we have space for a number of pages and/or a number of files in the
668 int cachefiles_has_space(struct cachefiles_cache *cache,
669 unsigned fnr, unsigned bnr)
671 struct kstatfs stats;
674 .dentry = cache->mnt->mnt_root,
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,
687 /* find out how many pages of blockdev are available */
688 memset(&stats, 0, sizeof(stats));
690 ret = vfs_statfs(&path, &stats);
693 cachefiles_io_error(cache, "statfs failed");
694 _leave(" = %d", ret);
698 stats.f_bavail >>= cache->bshift;
700 //_debug("avail %llu,%llu",
701 // (unsigned long long) stats.f_ffree,
702 // (unsigned long long) stats.f_bavail);
704 /* see if there is sufficient space */
705 if (stats.f_ffree > fnr)
706 stats.f_ffree -= fnr;
710 if (stats.f_bavail > bnr)
711 stats.f_bavail -= bnr;
716 if (stats.f_ffree < cache->fstop ||
717 stats.f_bavail < cache->bstop)
721 if (stats.f_ffree < cache->fcull ||
722 stats.f_bavail < cache->bcull)
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)
730 _debug("cease culling");
731 cachefiles_state_changed(cache);
738 if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
739 _debug("### CULL CACHE ###");
740 cachefiles_state_changed(cache);
743 _leave(" = %d", ret);