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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> | |
24 | #include <linux/fs_struct.h> | |
25 | #include "internal.h" | |
26 | ||
27 | static int cachefiles_daemon_open(struct inode *, struct file *); | |
28 | static int cachefiles_daemon_release(struct inode *, struct file *); | |
29 | static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t, | |
30 | loff_t *); | |
31 | static ssize_t cachefiles_daemon_write(struct file *, const char __user *, | |
32 | size_t, loff_t *); | |
33 | static unsigned int cachefiles_daemon_poll(struct file *, | |
34 | struct poll_table_struct *); | |
35 | static int cachefiles_daemon_frun(struct cachefiles_cache *, char *); | |
36 | static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *); | |
37 | static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *); | |
38 | static int cachefiles_daemon_brun(struct cachefiles_cache *, char *); | |
39 | static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *); | |
40 | static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *); | |
41 | static int cachefiles_daemon_cull(struct cachefiles_cache *, char *); | |
42 | static int cachefiles_daemon_debug(struct cachefiles_cache *, char *); | |
43 | static int cachefiles_daemon_dir(struct cachefiles_cache *, char *); | |
44 | static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *); | |
45 | static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *); | |
46 | static int cachefiles_daemon_tag(struct cachefiles_cache *, char *); | |
47 | ||
48 | static unsigned long cachefiles_open; | |
49 | ||
50 | const struct file_operations cachefiles_daemon_fops = { | |
51 | .owner = THIS_MODULE, | |
52 | .open = cachefiles_daemon_open, | |
53 | .release = cachefiles_daemon_release, | |
54 | .read = cachefiles_daemon_read, | |
55 | .write = cachefiles_daemon_write, | |
56 | .poll = cachefiles_daemon_poll, | |
57 | }; | |
58 | ||
59 | struct cachefiles_daemon_cmd { | |
60 | char name[8]; | |
61 | int (*handler)(struct cachefiles_cache *cache, char *args); | |
62 | }; | |
63 | ||
64 | static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = { | |
65 | { "bind", cachefiles_daemon_bind }, | |
66 | { "brun", cachefiles_daemon_brun }, | |
67 | { "bcull", cachefiles_daemon_bcull }, | |
68 | { "bstop", cachefiles_daemon_bstop }, | |
69 | { "cull", cachefiles_daemon_cull }, | |
70 | { "debug", cachefiles_daemon_debug }, | |
71 | { "dir", cachefiles_daemon_dir }, | |
72 | { "frun", cachefiles_daemon_frun }, | |
73 | { "fcull", cachefiles_daemon_fcull }, | |
74 | { "fstop", cachefiles_daemon_fstop }, | |
75 | { "inuse", cachefiles_daemon_inuse }, | |
76 | { "secctx", cachefiles_daemon_secctx }, | |
77 | { "tag", cachefiles_daemon_tag }, | |
78 | { "", NULL } | |
79 | }; | |
80 | ||
81 | ||
82 | /* | |
83 | * do various checks | |
84 | */ | |
85 | static int cachefiles_daemon_open(struct inode *inode, struct file *file) | |
86 | { | |
87 | struct cachefiles_cache *cache; | |
88 | ||
89 | _enter(""); | |
90 | ||
91 | /* only the superuser may do this */ | |
92 | if (!capable(CAP_SYS_ADMIN)) | |
93 | return -EPERM; | |
94 | ||
95 | /* the cachefiles device may only be open once at a time */ | |
96 | if (xchg(&cachefiles_open, 1) == 1) | |
97 | return -EBUSY; | |
98 | ||
99 | /* allocate a cache record */ | |
100 | cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL); | |
101 | if (!cache) { | |
102 | cachefiles_open = 0; | |
103 | return -ENOMEM; | |
104 | } | |
105 | ||
106 | mutex_init(&cache->daemon_mutex); | |
107 | cache->active_nodes = RB_ROOT; | |
108 | rwlock_init(&cache->active_lock); | |
109 | init_waitqueue_head(&cache->daemon_pollwq); | |
110 | ||
111 | /* set default caching limits | |
112 | * - limit at 1% free space and/or free files | |
113 | * - cull below 5% free space and/or free files | |
114 | * - cease culling above 7% free space and/or free files | |
115 | */ | |
116 | cache->frun_percent = 7; | |
117 | cache->fcull_percent = 5; | |
118 | cache->fstop_percent = 1; | |
119 | cache->brun_percent = 7; | |
120 | cache->bcull_percent = 5; | |
121 | cache->bstop_percent = 1; | |
122 | ||
123 | file->private_data = cache; | |
124 | cache->cachefilesd = file; | |
125 | return 0; | |
126 | } | |
127 | ||
128 | /* | |
129 | * release a cache | |
130 | */ | |
131 | static int cachefiles_daemon_release(struct inode *inode, struct file *file) | |
132 | { | |
133 | struct cachefiles_cache *cache = file->private_data; | |
134 | ||
135 | _enter(""); | |
136 | ||
137 | ASSERT(cache); | |
138 | ||
139 | set_bit(CACHEFILES_DEAD, &cache->flags); | |
140 | ||
141 | cachefiles_daemon_unbind(cache); | |
142 | ||
143 | ASSERT(!cache->active_nodes.rb_node); | |
144 | ||
145 | /* clean up the control file interface */ | |
146 | cache->cachefilesd = NULL; | |
147 | file->private_data = NULL; | |
148 | cachefiles_open = 0; | |
149 | ||
150 | kfree(cache); | |
151 | ||
152 | _leave(""); | |
153 | return 0; | |
154 | } | |
155 | ||
156 | /* | |
157 | * read the cache state | |
158 | */ | |
159 | static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, | |
160 | size_t buflen, loff_t *pos) | |
161 | { | |
162 | struct cachefiles_cache *cache = file->private_data; | |
163 | char buffer[256]; | |
164 | int n; | |
165 | ||
166 | //_enter(",,%zu,", buflen); | |
167 | ||
168 | if (!test_bit(CACHEFILES_READY, &cache->flags)) | |
169 | return 0; | |
170 | ||
171 | /* check how much space the cache has */ | |
172 | cachefiles_has_space(cache, 0, 0); | |
173 | ||
174 | /* summarise */ | |
175 | clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags); | |
176 | ||
177 | n = snprintf(buffer, sizeof(buffer), | |
178 | "cull=%c" | |
179 | " frun=%llx" | |
180 | " fcull=%llx" | |
181 | " fstop=%llx" | |
182 | " brun=%llx" | |
183 | " bcull=%llx" | |
184 | " bstop=%llx", | |
185 | test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0', | |
186 | (unsigned long long) cache->frun, | |
187 | (unsigned long long) cache->fcull, | |
188 | (unsigned long long) cache->fstop, | |
189 | (unsigned long long) cache->brun, | |
190 | (unsigned long long) cache->bcull, | |
191 | (unsigned long long) cache->bstop | |
192 | ); | |
193 | ||
194 | if (n > buflen) | |
195 | return -EMSGSIZE; | |
196 | ||
197 | if (copy_to_user(_buffer, buffer, n) != 0) | |
198 | return -EFAULT; | |
199 | ||
200 | return n; | |
201 | } | |
202 | ||
203 | /* | |
204 | * command the cache | |
205 | */ | |
206 | static ssize_t cachefiles_daemon_write(struct file *file, | |
207 | const char __user *_data, | |
208 | size_t datalen, | |
209 | loff_t *pos) | |
210 | { | |
211 | const struct cachefiles_daemon_cmd *cmd; | |
212 | struct cachefiles_cache *cache = file->private_data; | |
213 | ssize_t ret; | |
214 | char *data, *args, *cp; | |
215 | ||
216 | //_enter(",,%zu,", datalen); | |
217 | ||
218 | ASSERT(cache); | |
219 | ||
220 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) | |
221 | return -EIO; | |
222 | ||
223 | if (datalen < 0 || datalen > PAGE_SIZE - 1) | |
224 | return -EOPNOTSUPP; | |
225 | ||
226 | /* drag the command string into the kernel so we can parse it */ | |
227 | data = kmalloc(datalen + 1, GFP_KERNEL); | |
228 | if (!data) | |
229 | return -ENOMEM; | |
230 | ||
231 | ret = -EFAULT; | |
232 | if (copy_from_user(data, _data, datalen) != 0) | |
233 | goto error; | |
234 | ||
235 | data[datalen] = '\0'; | |
236 | ||
237 | ret = -EINVAL; | |
238 | if (memchr(data, '\0', datalen)) | |
239 | goto error; | |
240 | ||
241 | /* strip any newline */ | |
242 | cp = memchr(data, '\n', datalen); | |
243 | if (cp) { | |
244 | if (cp == data) | |
245 | goto error; | |
246 | ||
247 | *cp = '\0'; | |
248 | } | |
249 | ||
250 | /* parse the command */ | |
251 | ret = -EOPNOTSUPP; | |
252 | ||
253 | for (args = data; *args; args++) | |
254 | if (isspace(*args)) | |
255 | break; | |
256 | if (*args) { | |
257 | if (args == data) | |
258 | goto error; | |
259 | *args = '\0'; | |
260 | for (args++; isspace(*args); args++) | |
261 | continue; | |
262 | } | |
263 | ||
264 | /* run the appropriate command handler */ | |
265 | for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++) | |
266 | if (strcmp(cmd->name, data) == 0) | |
267 | goto found_command; | |
268 | ||
269 | error: | |
270 | kfree(data); | |
271 | //_leave(" = %zd", ret); | |
272 | return ret; | |
273 | ||
274 | found_command: | |
275 | mutex_lock(&cache->daemon_mutex); | |
276 | ||
277 | ret = -EIO; | |
278 | if (!test_bit(CACHEFILES_DEAD, &cache->flags)) | |
279 | ret = cmd->handler(cache, args); | |
280 | ||
281 | mutex_unlock(&cache->daemon_mutex); | |
282 | ||
283 | if (ret == 0) | |
284 | ret = datalen; | |
285 | goto error; | |
286 | } | |
287 | ||
288 | /* | |
289 | * poll for culling state | |
290 | * - use POLLOUT to indicate culling state | |
291 | */ | |
292 | static unsigned int cachefiles_daemon_poll(struct file *file, | |
293 | struct poll_table_struct *poll) | |
294 | { | |
295 | struct cachefiles_cache *cache = file->private_data; | |
296 | unsigned int mask; | |
297 | ||
298 | poll_wait(file, &cache->daemon_pollwq, poll); | |
299 | mask = 0; | |
300 | ||
301 | if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) | |
302 | mask |= POLLIN; | |
303 | ||
304 | if (test_bit(CACHEFILES_CULLING, &cache->flags)) | |
305 | mask |= POLLOUT; | |
306 | ||
307 | return mask; | |
308 | } | |
309 | ||
310 | /* | |
311 | * give a range error for cache space constraints | |
312 | * - can be tail-called | |
313 | */ | |
314 | static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, | |
315 | char *args) | |
316 | { | |
317 | kerror("Free space limits must be in range" | |
318 | " 0%%<=stop<cull<run<100%%"); | |
319 | ||
320 | return -EINVAL; | |
321 | } | |
322 | ||
323 | /* | |
324 | * set the percentage of files at which to stop culling | |
325 | * - command: "frun <N>%" | |
326 | */ | |
327 | static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) | |
328 | { | |
329 | unsigned long frun; | |
330 | ||
331 | _enter(",%s", args); | |
332 | ||
333 | if (!*args) | |
334 | return -EINVAL; | |
335 | ||
336 | frun = simple_strtoul(args, &args, 10); | |
337 | if (args[0] != '%' || args[1] != '\0') | |
338 | return -EINVAL; | |
339 | ||
340 | if (frun <= cache->fcull_percent || frun >= 100) | |
341 | return cachefiles_daemon_range_error(cache, args); | |
342 | ||
343 | cache->frun_percent = frun; | |
344 | return 0; | |
345 | } | |
346 | ||
347 | /* | |
348 | * set the percentage of files at which to start culling | |
349 | * - command: "fcull <N>%" | |
350 | */ | |
351 | static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) | |
352 | { | |
353 | unsigned long fcull; | |
354 | ||
355 | _enter(",%s", args); | |
356 | ||
357 | if (!*args) | |
358 | return -EINVAL; | |
359 | ||
360 | fcull = simple_strtoul(args, &args, 10); | |
361 | if (args[0] != '%' || args[1] != '\0') | |
362 | return -EINVAL; | |
363 | ||
364 | if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent) | |
365 | return cachefiles_daemon_range_error(cache, args); | |
366 | ||
367 | cache->fcull_percent = fcull; | |
368 | return 0; | |
369 | } | |
370 | ||
371 | /* | |
372 | * set the percentage of files at which to stop allocating | |
373 | * - command: "fstop <N>%" | |
374 | */ | |
375 | static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) | |
376 | { | |
377 | unsigned long fstop; | |
378 | ||
379 | _enter(",%s", args); | |
380 | ||
381 | if (!*args) | |
382 | return -EINVAL; | |
383 | ||
384 | fstop = simple_strtoul(args, &args, 10); | |
385 | if (args[0] != '%' || args[1] != '\0') | |
386 | return -EINVAL; | |
387 | ||
388 | if (fstop < 0 || fstop >= cache->fcull_percent) | |
389 | return cachefiles_daemon_range_error(cache, args); | |
390 | ||
391 | cache->fstop_percent = fstop; | |
392 | return 0; | |
393 | } | |
394 | ||
395 | /* | |
396 | * set the percentage of blocks at which to stop culling | |
397 | * - command: "brun <N>%" | |
398 | */ | |
399 | static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) | |
400 | { | |
401 | unsigned long brun; | |
402 | ||
403 | _enter(",%s", args); | |
404 | ||
405 | if (!*args) | |
406 | return -EINVAL; | |
407 | ||
408 | brun = simple_strtoul(args, &args, 10); | |
409 | if (args[0] != '%' || args[1] != '\0') | |
410 | return -EINVAL; | |
411 | ||
412 | if (brun <= cache->bcull_percent || brun >= 100) | |
413 | return cachefiles_daemon_range_error(cache, args); | |
414 | ||
415 | cache->brun_percent = brun; | |
416 | return 0; | |
417 | } | |
418 | ||
419 | /* | |
420 | * set the percentage of blocks at which to start culling | |
421 | * - command: "bcull <N>%" | |
422 | */ | |
423 | static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) | |
424 | { | |
425 | unsigned long bcull; | |
426 | ||
427 | _enter(",%s", args); | |
428 | ||
429 | if (!*args) | |
430 | return -EINVAL; | |
431 | ||
432 | bcull = simple_strtoul(args, &args, 10); | |
433 | if (args[0] != '%' || args[1] != '\0') | |
434 | return -EINVAL; | |
435 | ||
436 | if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent) | |
437 | return cachefiles_daemon_range_error(cache, args); | |
438 | ||
439 | cache->bcull_percent = bcull; | |
440 | return 0; | |
441 | } | |
442 | ||
443 | /* | |
444 | * set the percentage of blocks at which to stop allocating | |
445 | * - command: "bstop <N>%" | |
446 | */ | |
447 | static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) | |
448 | { | |
449 | unsigned long bstop; | |
450 | ||
451 | _enter(",%s", args); | |
452 | ||
453 | if (!*args) | |
454 | return -EINVAL; | |
455 | ||
456 | bstop = simple_strtoul(args, &args, 10); | |
457 | if (args[0] != '%' || args[1] != '\0') | |
458 | return -EINVAL; | |
459 | ||
460 | if (bstop < 0 || bstop >= cache->bcull_percent) | |
461 | return cachefiles_daemon_range_error(cache, args); | |
462 | ||
463 | cache->bstop_percent = bstop; | |
464 | return 0; | |
465 | } | |
466 | ||
467 | /* | |
468 | * set the cache directory | |
469 | * - command: "dir <name>" | |
470 | */ | |
471 | static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) | |
472 | { | |
473 | char *dir; | |
474 | ||
475 | _enter(",%s", args); | |
476 | ||
477 | if (!*args) { | |
478 | kerror("Empty directory specified"); | |
479 | return -EINVAL; | |
480 | } | |
481 | ||
482 | if (cache->rootdirname) { | |
483 | kerror("Second cache directory specified"); | |
484 | return -EEXIST; | |
485 | } | |
486 | ||
487 | dir = kstrdup(args, GFP_KERNEL); | |
488 | if (!dir) | |
489 | return -ENOMEM; | |
490 | ||
491 | cache->rootdirname = dir; | |
492 | return 0; | |
493 | } | |
494 | ||
495 | /* | |
496 | * set the cache security context | |
497 | * - command: "secctx <ctx>" | |
498 | */ | |
499 | static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) | |
500 | { | |
501 | char *secctx; | |
502 | ||
503 | _enter(",%s", args); | |
504 | ||
505 | if (!*args) { | |
506 | kerror("Empty security context specified"); | |
507 | return -EINVAL; | |
508 | } | |
509 | ||
510 | if (cache->secctx) { | |
511 | kerror("Second security context specified"); | |
512 | return -EINVAL; | |
513 | } | |
514 | ||
515 | secctx = kstrdup(args, GFP_KERNEL); | |
516 | if (!secctx) | |
517 | return -ENOMEM; | |
518 | ||
519 | cache->secctx = secctx; | |
520 | return 0; | |
521 | } | |
522 | ||
523 | /* | |
524 | * set the cache tag | |
525 | * - command: "tag <name>" | |
526 | */ | |
527 | static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) | |
528 | { | |
529 | char *tag; | |
530 | ||
531 | _enter(",%s", args); | |
532 | ||
533 | if (!*args) { | |
534 | kerror("Empty tag specified"); | |
535 | return -EINVAL; | |
536 | } | |
537 | ||
538 | if (cache->tag) | |
539 | return -EEXIST; | |
540 | ||
541 | tag = kstrdup(args, GFP_KERNEL); | |
542 | if (!tag) | |
543 | return -ENOMEM; | |
544 | ||
545 | cache->tag = tag; | |
546 | return 0; | |
547 | } | |
548 | ||
549 | /* | |
550 | * request a node in the cache be culled from the current working directory | |
551 | * - command: "cull <name>" | |
552 | */ | |
553 | static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) | |
554 | { | |
555 | struct fs_struct *fs; | |
556 | struct dentry *dir; | |
557 | const struct cred *saved_cred; | |
558 | int ret; | |
559 | ||
560 | _enter(",%s", args); | |
561 | ||
562 | if (strchr(args, '/')) | |
563 | goto inval; | |
564 | ||
565 | if (!test_bit(CACHEFILES_READY, &cache->flags)) { | |
566 | kerror("cull applied to unready cache"); | |
567 | return -EIO; | |
568 | } | |
569 | ||
570 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) { | |
571 | kerror("cull applied to dead cache"); | |
572 | return -EIO; | |
573 | } | |
574 | ||
575 | /* extract the directory dentry from the cwd */ | |
576 | fs = current->fs; | |
577 | read_lock(&fs->lock); | |
578 | dir = dget(fs->pwd.dentry); | |
579 | read_unlock(&fs->lock); | |
580 | ||
581 | if (!S_ISDIR(dir->d_inode->i_mode)) | |
582 | goto notdir; | |
583 | ||
584 | cachefiles_begin_secure(cache, &saved_cred); | |
585 | ret = cachefiles_cull(cache, dir, args); | |
586 | cachefiles_end_secure(cache, saved_cred); | |
587 | ||
588 | dput(dir); | |
589 | _leave(" = %d", ret); | |
590 | return ret; | |
591 | ||
592 | notdir: | |
593 | dput(dir); | |
594 | kerror("cull command requires dirfd to be a directory"); | |
595 | return -ENOTDIR; | |
596 | ||
597 | inval: | |
598 | kerror("cull command requires dirfd and filename"); | |
599 | return -EINVAL; | |
600 | } | |
601 | ||
602 | /* | |
603 | * set debugging mode | |
604 | * - command: "debug <mask>" | |
605 | */ | |
606 | static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) | |
607 | { | |
608 | unsigned long mask; | |
609 | ||
610 | _enter(",%s", args); | |
611 | ||
612 | mask = simple_strtoul(args, &args, 0); | |
613 | if (args[0] != '\0') | |
614 | goto inval; | |
615 | ||
616 | cachefiles_debug = mask; | |
617 | _leave(" = 0"); | |
618 | return 0; | |
619 | ||
620 | inval: | |
621 | kerror("debug command requires mask"); | |
622 | return -EINVAL; | |
623 | } | |
624 | ||
625 | /* | |
626 | * find out whether an object in the current working directory is in use or not | |
627 | * - command: "inuse <name>" | |
628 | */ | |
629 | static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) | |
630 | { | |
631 | struct fs_struct *fs; | |
632 | struct dentry *dir; | |
633 | const struct cred *saved_cred; | |
634 | int ret; | |
635 | ||
636 | //_enter(",%s", args); | |
637 | ||
638 | if (strchr(args, '/')) | |
639 | goto inval; | |
640 | ||
641 | if (!test_bit(CACHEFILES_READY, &cache->flags)) { | |
642 | kerror("inuse applied to unready cache"); | |
643 | return -EIO; | |
644 | } | |
645 | ||
646 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) { | |
647 | kerror("inuse applied to dead cache"); | |
648 | return -EIO; | |
649 | } | |
650 | ||
651 | /* extract the directory dentry from the cwd */ | |
652 | fs = current->fs; | |
653 | read_lock(&fs->lock); | |
654 | dir = dget(fs->pwd.dentry); | |
655 | read_unlock(&fs->lock); | |
656 | ||
657 | if (!S_ISDIR(dir->d_inode->i_mode)) | |
658 | goto notdir; | |
659 | ||
660 | cachefiles_begin_secure(cache, &saved_cred); | |
661 | ret = cachefiles_check_in_use(cache, dir, args); | |
662 | cachefiles_end_secure(cache, saved_cred); | |
663 | ||
664 | dput(dir); | |
665 | //_leave(" = %d", ret); | |
666 | return ret; | |
667 | ||
668 | notdir: | |
669 | dput(dir); | |
670 | kerror("inuse command requires dirfd to be a directory"); | |
671 | return -ENOTDIR; | |
672 | ||
673 | inval: | |
674 | kerror("inuse command requires dirfd and filename"); | |
675 | return -EINVAL; | |
676 | } | |
677 | ||
678 | /* | |
679 | * see if we have space for a number of pages and/or a number of files in the | |
680 | * cache | |
681 | */ | |
682 | int cachefiles_has_space(struct cachefiles_cache *cache, | |
683 | unsigned fnr, unsigned bnr) | |
684 | { | |
685 | struct kstatfs stats; | |
686 | int ret; | |
687 | ||
688 | //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u", | |
689 | // (unsigned long long) cache->frun, | |
690 | // (unsigned long long) cache->fcull, | |
691 | // (unsigned long long) cache->fstop, | |
692 | // (unsigned long long) cache->brun, | |
693 | // (unsigned long long) cache->bcull, | |
694 | // (unsigned long long) cache->bstop, | |
695 | // fnr, bnr); | |
696 | ||
697 | /* find out how many pages of blockdev are available */ | |
698 | memset(&stats, 0, sizeof(stats)); | |
699 | ||
700 | ret = vfs_statfs(cache->mnt->mnt_root, &stats); | |
701 | if (ret < 0) { | |
702 | if (ret == -EIO) | |
703 | cachefiles_io_error(cache, "statfs failed"); | |
704 | _leave(" = %d", ret); | |
705 | return ret; | |
706 | } | |
707 | ||
708 | stats.f_bavail >>= cache->bshift; | |
709 | ||
710 | //_debug("avail %llu,%llu", | |
711 | // (unsigned long long) stats.f_ffree, | |
712 | // (unsigned long long) stats.f_bavail); | |
713 | ||
714 | /* see if there is sufficient space */ | |
715 | if (stats.f_ffree > fnr) | |
716 | stats.f_ffree -= fnr; | |
717 | else | |
718 | stats.f_ffree = 0; | |
719 | ||
720 | if (stats.f_bavail > bnr) | |
721 | stats.f_bavail -= bnr; | |
722 | else | |
723 | stats.f_bavail = 0; | |
724 | ||
725 | ret = -ENOBUFS; | |
726 | if (stats.f_ffree < cache->fstop || | |
727 | stats.f_bavail < cache->bstop) | |
728 | goto begin_cull; | |
729 | ||
730 | ret = 0; | |
731 | if (stats.f_ffree < cache->fcull || | |
732 | stats.f_bavail < cache->bcull) | |
733 | goto begin_cull; | |
734 | ||
735 | if (test_bit(CACHEFILES_CULLING, &cache->flags) && | |
736 | stats.f_ffree >= cache->frun && | |
737 | stats.f_bavail >= cache->brun && | |
738 | test_and_clear_bit(CACHEFILES_CULLING, &cache->flags) | |
739 | ) { | |
740 | _debug("cease culling"); | |
741 | cachefiles_state_changed(cache); | |
742 | } | |
743 | ||
744 | //_leave(" = 0"); | |
745 | return 0; | |
746 | ||
747 | begin_cull: | |
748 | if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { | |
749 | _debug("### CULL CACHE ###"); | |
750 | cachefiles_state_changed(cache); | |
751 | } | |
752 | ||
753 | _leave(" = %d", ret); | |
754 | return ret; | |
755 | } |