David Howells | 9ae326a | 2009-04-03 16:42:41 +0100 | [diff] [blame] | 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 | } |