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
= kmalloc(datalen
+ 1, GFP_KERNEL
);
234 if (copy_from_user(data
, _data
, datalen
) != 0)
237 data
[datalen
] = '\0';
240 if (memchr(data
, '\0', datalen
))
243 /* strip any newline */
244 cp
= memchr(data
, '\n', datalen
);
252 /* parse the command */
255 for (args
= data
; *args
; args
++)
262 args
= skip_spaces(++args
);
265 /* run the appropriate command handler */
266 for (cmd
= cachefiles_daemon_cmds
; cmd
->name
[0]; cmd
++)
267 if (strcmp(cmd
->name
, data
) == 0)
272 //_leave(" = %zd", ret);
276 mutex_lock(&cache
->daemon_mutex
);
279 if (!test_bit(CACHEFILES_DEAD
, &cache
->flags
))
280 ret
= cmd
->handler(cache
, args
);
282 mutex_unlock(&cache
->daemon_mutex
);
290 * poll for culling state
291 * - use POLLOUT to indicate culling state
293 static unsigned int cachefiles_daemon_poll(struct file
*file
,
294 struct poll_table_struct
*poll
)
296 struct cachefiles_cache
*cache
= file
->private_data
;
299 poll_wait(file
, &cache
->daemon_pollwq
, poll
);
302 if (test_bit(CACHEFILES_STATE_CHANGED
, &cache
->flags
))
305 if (test_bit(CACHEFILES_CULLING
, &cache
->flags
))
312 * give a range error for cache space constraints
313 * - can be tail-called
315 static int cachefiles_daemon_range_error(struct cachefiles_cache
*cache
,
318 pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
324 * set the percentage of files at which to stop culling
325 * - command: "frun <N>%"
327 static int cachefiles_daemon_frun(struct cachefiles_cache
*cache
, char *args
)
336 frun
= simple_strtoul(args
, &args
, 10);
337 if (args
[0] != '%' || args
[1] != '\0')
340 if (frun
<= cache
->fcull_percent
|| frun
>= 100)
341 return cachefiles_daemon_range_error(cache
, args
);
343 cache
->frun_percent
= frun
;
348 * set the percentage of files at which to start culling
349 * - command: "fcull <N>%"
351 static int cachefiles_daemon_fcull(struct cachefiles_cache
*cache
, char *args
)
360 fcull
= simple_strtoul(args
, &args
, 10);
361 if (args
[0] != '%' || args
[1] != '\0')
364 if (fcull
<= cache
->fstop_percent
|| fcull
>= cache
->frun_percent
)
365 return cachefiles_daemon_range_error(cache
, args
);
367 cache
->fcull_percent
= fcull
;
372 * set the percentage of files at which to stop allocating
373 * - command: "fstop <N>%"
375 static int cachefiles_daemon_fstop(struct cachefiles_cache
*cache
, char *args
)
384 fstop
= simple_strtoul(args
, &args
, 10);
385 if (args
[0] != '%' || args
[1] != '\0')
388 if (fstop
< 0 || fstop
>= cache
->fcull_percent
)
389 return cachefiles_daemon_range_error(cache
, args
);
391 cache
->fstop_percent
= fstop
;
396 * set the percentage of blocks at which to stop culling
397 * - command: "brun <N>%"
399 static int cachefiles_daemon_brun(struct cachefiles_cache
*cache
, char *args
)
408 brun
= simple_strtoul(args
, &args
, 10);
409 if (args
[0] != '%' || args
[1] != '\0')
412 if (brun
<= cache
->bcull_percent
|| brun
>= 100)
413 return cachefiles_daemon_range_error(cache
, args
);
415 cache
->brun_percent
= brun
;
420 * set the percentage of blocks at which to start culling
421 * - command: "bcull <N>%"
423 static int cachefiles_daemon_bcull(struct cachefiles_cache
*cache
, char *args
)
432 bcull
= simple_strtoul(args
, &args
, 10);
433 if (args
[0] != '%' || args
[1] != '\0')
436 if (bcull
<= cache
->bstop_percent
|| bcull
>= cache
->brun_percent
)
437 return cachefiles_daemon_range_error(cache
, args
);
439 cache
->bcull_percent
= bcull
;
444 * set the percentage of blocks at which to stop allocating
445 * - command: "bstop <N>%"
447 static int cachefiles_daemon_bstop(struct cachefiles_cache
*cache
, char *args
)
456 bstop
= simple_strtoul(args
, &args
, 10);
457 if (args
[0] != '%' || args
[1] != '\0')
460 if (bstop
< 0 || bstop
>= cache
->bcull_percent
)
461 return cachefiles_daemon_range_error(cache
, args
);
463 cache
->bstop_percent
= bstop
;
468 * set the cache directory
469 * - command: "dir <name>"
471 static int cachefiles_daemon_dir(struct cachefiles_cache
*cache
, char *args
)
478 pr_err("Empty directory specified\n");
482 if (cache
->rootdirname
) {
483 pr_err("Second cache directory specified\n");
487 dir
= kstrdup(args
, GFP_KERNEL
);
491 cache
->rootdirname
= dir
;
496 * set the cache security context
497 * - command: "secctx <ctx>"
499 static int cachefiles_daemon_secctx(struct cachefiles_cache
*cache
, char *args
)
506 pr_err("Empty security context specified\n");
511 pr_err("Second security context specified\n");
515 secctx
= kstrdup(args
, GFP_KERNEL
);
519 cache
->secctx
= secctx
;
525 * - command: "tag <name>"
527 static int cachefiles_daemon_tag(struct cachefiles_cache
*cache
, char *args
)
534 pr_err("Empty tag specified\n");
541 tag
= kstrdup(args
, GFP_KERNEL
);
550 * request a node in the cache be culled from the current working directory
551 * - command: "cull <name>"
553 static int cachefiles_daemon_cull(struct cachefiles_cache
*cache
, char *args
)
556 const struct cred
*saved_cred
;
561 if (strchr(args
, '/'))
564 if (!test_bit(CACHEFILES_READY
, &cache
->flags
)) {
565 pr_err("cull applied to unready cache\n");
569 if (test_bit(CACHEFILES_DEAD
, &cache
->flags
)) {
570 pr_err("cull applied to dead cache\n");
574 /* extract the directory dentry from the cwd */
575 get_fs_pwd(current
->fs
, &path
);
577 if (!d_can_lookup(path
.dentry
))
580 cachefiles_begin_secure(cache
, &saved_cred
);
581 ret
= cachefiles_cull(cache
, path
.dentry
, args
);
582 cachefiles_end_secure(cache
, saved_cred
);
585 _leave(" = %d", ret
);
590 pr_err("cull command requires dirfd to be a directory\n");
594 pr_err("cull command requires dirfd and filename\n");
600 * - command: "debug <mask>"
602 static int cachefiles_daemon_debug(struct cachefiles_cache
*cache
, char *args
)
608 mask
= simple_strtoul(args
, &args
, 0);
612 cachefiles_debug
= mask
;
617 pr_err("debug command requires mask\n");
622 * find out whether an object in the current working directory is in use or not
623 * - command: "inuse <name>"
625 static int cachefiles_daemon_inuse(struct cachefiles_cache
*cache
, char *args
)
628 const struct cred
*saved_cred
;
631 //_enter(",%s", args);
633 if (strchr(args
, '/'))
636 if (!test_bit(CACHEFILES_READY
, &cache
->flags
)) {
637 pr_err("inuse applied to unready cache\n");
641 if (test_bit(CACHEFILES_DEAD
, &cache
->flags
)) {
642 pr_err("inuse applied to dead cache\n");
646 /* extract the directory dentry from the cwd */
647 get_fs_pwd(current
->fs
, &path
);
649 if (!d_can_lookup(path
.dentry
))
652 cachefiles_begin_secure(cache
, &saved_cred
);
653 ret
= cachefiles_check_in_use(cache
, path
.dentry
, args
);
654 cachefiles_end_secure(cache
, saved_cred
);
657 //_leave(" = %d", ret);
662 pr_err("inuse command requires dirfd to be a directory\n");
666 pr_err("inuse command requires dirfd and filename\n");
671 * see if we have space for a number of pages and/or a number of files in the
674 int cachefiles_has_space(struct cachefiles_cache
*cache
,
675 unsigned fnr
, unsigned bnr
)
677 struct kstatfs stats
;
680 .dentry
= cache
->mnt
->mnt_root
,
684 //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
685 // (unsigned long long) cache->frun,
686 // (unsigned long long) cache->fcull,
687 // (unsigned long long) cache->fstop,
688 // (unsigned long long) cache->brun,
689 // (unsigned long long) cache->bcull,
690 // (unsigned long long) cache->bstop,
693 /* find out how many pages of blockdev are available */
694 memset(&stats
, 0, sizeof(stats
));
696 ret
= vfs_statfs(&path
, &stats
);
699 cachefiles_io_error(cache
, "statfs failed");
700 _leave(" = %d", ret
);
704 stats
.f_bavail
>>= cache
->bshift
;
706 //_debug("avail %llu,%llu",
707 // (unsigned long long) stats.f_ffree,
708 // (unsigned long long) stats.f_bavail);
710 /* see if there is sufficient space */
711 if (stats
.f_ffree
> fnr
)
712 stats
.f_ffree
-= fnr
;
716 if (stats
.f_bavail
> bnr
)
717 stats
.f_bavail
-= bnr
;
722 if (stats
.f_ffree
< cache
->fstop
||
723 stats
.f_bavail
< cache
->bstop
)
727 if (stats
.f_ffree
< cache
->fcull
||
728 stats
.f_bavail
< cache
->bcull
)
731 if (test_bit(CACHEFILES_CULLING
, &cache
->flags
) &&
732 stats
.f_ffree
>= cache
->frun
&&
733 stats
.f_bavail
>= cache
->brun
&&
734 test_and_clear_bit(CACHEFILES_CULLING
, &cache
->flags
)
736 _debug("cease culling");
737 cachefiles_state_changed(cache
);
744 if (!test_and_set_bit(CACHEFILES_CULLING
, &cache
->flags
)) {
745 _debug("### CULL CACHE ###");
746 cachefiles_state_changed(cache
);
749 _leave(" = %d", ret
);