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9ae326a6 DH |
1 | /* CacheFiles path walking and related routines |
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/sched.h> | |
14 | #include <linux/file.h> | |
15 | #include <linux/fs.h> | |
16 | #include <linux/fsnotify.h> | |
17 | #include <linux/quotaops.h> | |
18 | #include <linux/xattr.h> | |
19 | #include <linux/mount.h> | |
20 | #include <linux/namei.h> | |
21 | #include <linux/security.h> | |
22 | #include "internal.h" | |
23 | ||
d0e27b78 DH |
24 | #define CACHEFILES_KEYBUF_SIZE 512 |
25 | ||
26 | /* | |
27 | * dump debugging info about an object | |
28 | */ | |
29 | static noinline | |
30 | void __cachefiles_printk_object(struct cachefiles_object *object, | |
31 | const char *prefix, | |
32 | u8 *keybuf) | |
33 | { | |
34 | struct fscache_cookie *cookie; | |
35 | unsigned keylen, loop; | |
36 | ||
37 | printk(KERN_ERR "%sobject: OBJ%x\n", | |
38 | prefix, object->fscache.debug_id); | |
39 | printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n", | |
40 | prefix, fscache_object_states[object->fscache.state], | |
41 | object->fscache.flags, object->fscache.work.flags, | |
42 | object->fscache.events, | |
43 | object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK); | |
44 | printk(KERN_ERR "%sops=%u inp=%u exc=%u\n", | |
45 | prefix, object->fscache.n_ops, object->fscache.n_in_progress, | |
46 | object->fscache.n_exclusive); | |
47 | printk(KERN_ERR "%sparent=%p\n", | |
48 | prefix, object->fscache.parent); | |
49 | ||
50 | spin_lock(&object->fscache.lock); | |
51 | cookie = object->fscache.cookie; | |
52 | if (cookie) { | |
53 | printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n", | |
54 | prefix, | |
55 | object->fscache.cookie, | |
56 | object->fscache.cookie->parent, | |
57 | object->fscache.cookie->netfs_data, | |
58 | object->fscache.cookie->flags); | |
59 | if (keybuf) | |
60 | keylen = cookie->def->get_key(cookie->netfs_data, keybuf, | |
61 | CACHEFILES_KEYBUF_SIZE); | |
62 | else | |
63 | keylen = 0; | |
64 | } else { | |
65 | printk(KERN_ERR "%scookie=NULL\n", prefix); | |
66 | keylen = 0; | |
67 | } | |
68 | spin_unlock(&object->fscache.lock); | |
69 | ||
70 | if (keylen) { | |
71 | printk(KERN_ERR "%skey=[%u] '", prefix, keylen); | |
72 | for (loop = 0; loop < keylen; loop++) | |
73 | printk("%02x", keybuf[loop]); | |
74 | printk("'\n"); | |
75 | } | |
76 | } | |
77 | ||
78 | /* | |
79 | * dump debugging info about a pair of objects | |
80 | */ | |
81 | static noinline void cachefiles_printk_object(struct cachefiles_object *object, | |
82 | struct cachefiles_object *xobject) | |
83 | { | |
84 | u8 *keybuf; | |
85 | ||
86 | keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); | |
87 | if (object) | |
88 | __cachefiles_printk_object(object, "", keybuf); | |
89 | if (xobject) | |
90 | __cachefiles_printk_object(xobject, "x", keybuf); | |
91 | kfree(keybuf); | |
92 | } | |
93 | ||
9ae326a6 DH |
94 | /* |
95 | * record the fact that an object is now active | |
96 | */ | |
fee096de DH |
97 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
98 | struct cachefiles_object *object) | |
9ae326a6 DH |
99 | { |
100 | struct cachefiles_object *xobject; | |
101 | struct rb_node **_p, *_parent = NULL; | |
102 | struct dentry *dentry; | |
103 | ||
104 | _enter(",%p", object); | |
105 | ||
106 | try_again: | |
107 | write_lock(&cache->active_lock); | |
108 | ||
d0e27b78 DH |
109 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
110 | printk(KERN_ERR "CacheFiles: Error: Object already active\n"); | |
111 | cachefiles_printk_object(object, NULL); | |
9ae326a6 | 112 | BUG(); |
d0e27b78 | 113 | } |
9ae326a6 DH |
114 | |
115 | dentry = object->dentry; | |
116 | _p = &cache->active_nodes.rb_node; | |
117 | while (*_p) { | |
118 | _parent = *_p; | |
119 | xobject = rb_entry(_parent, | |
120 | struct cachefiles_object, active_node); | |
121 | ||
122 | ASSERT(xobject != object); | |
123 | ||
124 | if (xobject->dentry > dentry) | |
125 | _p = &(*_p)->rb_left; | |
126 | else if (xobject->dentry < dentry) | |
127 | _p = &(*_p)->rb_right; | |
128 | else | |
129 | goto wait_for_old_object; | |
130 | } | |
131 | ||
132 | rb_link_node(&object->active_node, _parent, _p); | |
133 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
134 | ||
135 | write_unlock(&cache->active_lock); | |
fee096de DH |
136 | _leave(" = 0"); |
137 | return 0; | |
9ae326a6 DH |
138 | |
139 | /* an old object from a previous incarnation is hogging the slot - we | |
140 | * need to wait for it to be destroyed */ | |
141 | wait_for_old_object: | |
142 | if (xobject->fscache.state < FSCACHE_OBJECT_DYING) { | |
143 | printk(KERN_ERR "\n"); | |
144 | printk(KERN_ERR "CacheFiles: Error:" | |
145 | " Unexpected object collision\n"); | |
d0e27b78 | 146 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
147 | BUG(); |
148 | } | |
149 | atomic_inc(&xobject->usage); | |
150 | write_unlock(&cache->active_lock); | |
151 | ||
fee096de DH |
152 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
153 | wait_queue_head_t *wq; | |
154 | ||
155 | signed long timeout = 60 * HZ; | |
156 | wait_queue_t wait; | |
157 | bool requeue; | |
158 | ||
159 | /* if the object we're waiting for is queued for processing, | |
160 | * then just put ourselves on the queue behind it */ | |
161 | if (slow_work_is_queued(&xobject->fscache.work)) { | |
162 | _debug("queue OBJ%x behind OBJ%x immediately", | |
163 | object->fscache.debug_id, | |
164 | xobject->fscache.debug_id); | |
165 | goto requeue; | |
166 | } | |
167 | ||
168 | /* otherwise we sleep until either the object we're waiting for | |
169 | * is done, or the slow-work facility wants the thread back to | |
170 | * do other work */ | |
171 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); | |
172 | init_wait(&wait); | |
173 | requeue = false; | |
174 | do { | |
175 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
176 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
177 | break; | |
178 | requeue = slow_work_sleep_till_thread_needed( | |
179 | &object->fscache.work, &timeout); | |
180 | } while (timeout > 0 && !requeue); | |
181 | finish_wait(wq, &wait); | |
182 | ||
183 | if (requeue && | |
184 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
185 | _debug("queue OBJ%x behind OBJ%x after wait", | |
186 | object->fscache.debug_id, | |
187 | xobject->fscache.debug_id); | |
188 | goto requeue; | |
189 | } | |
190 | ||
191 | if (timeout <= 0) { | |
192 | printk(KERN_ERR "\n"); | |
193 | printk(KERN_ERR "CacheFiles: Error: Overlong" | |
194 | " wait for old active object to go away\n"); | |
195 | cachefiles_printk_object(object, xobject); | |
196 | goto requeue; | |
197 | } | |
198 | } | |
199 | ||
200 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
9ae326a6 DH |
201 | |
202 | cache->cache.ops->put_object(&xobject->fscache); | |
203 | goto try_again; | |
fee096de DH |
204 | |
205 | requeue: | |
206 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
207 | cache->cache.ops->put_object(&xobject->fscache); | |
208 | _leave(" = -ETIMEDOUT"); | |
209 | return -ETIMEDOUT; | |
9ae326a6 DH |
210 | } |
211 | ||
212 | /* | |
213 | * delete an object representation from the cache | |
214 | * - file backed objects are unlinked | |
215 | * - directory backed objects are stuffed into the graveyard for userspace to | |
216 | * delete | |
217 | * - unlocks the directory mutex | |
218 | */ | |
219 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
220 | struct dentry *dir, | |
221 | struct dentry *rep) | |
222 | { | |
223 | struct dentry *grave, *trap; | |
224 | char nbuffer[8 + 8 + 1]; | |
225 | int ret; | |
226 | ||
227 | _enter(",'%*.*s','%*.*s'", | |
228 | dir->d_name.len, dir->d_name.len, dir->d_name.name, | |
229 | rep->d_name.len, rep->d_name.len, rep->d_name.name); | |
230 | ||
231 | /* non-directories can just be unlinked */ | |
232 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
233 | _debug("unlink stale object"); | |
234 | ret = vfs_unlink(dir->d_inode, rep); | |
235 | ||
236 | mutex_unlock(&dir->d_inode->i_mutex); | |
237 | ||
238 | if (ret == -EIO) | |
239 | cachefiles_io_error(cache, "Unlink failed"); | |
240 | ||
241 | _leave(" = %d", ret); | |
242 | return ret; | |
243 | } | |
244 | ||
245 | /* directories have to be moved to the graveyard */ | |
246 | _debug("move stale object to graveyard"); | |
247 | mutex_unlock(&dir->d_inode->i_mutex); | |
248 | ||
249 | try_again: | |
250 | /* first step is to make up a grave dentry in the graveyard */ | |
251 | sprintf(nbuffer, "%08x%08x", | |
252 | (uint32_t) get_seconds(), | |
253 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
254 | ||
255 | /* do the multiway lock magic */ | |
256 | trap = lock_rename(cache->graveyard, dir); | |
257 | ||
258 | /* do some checks before getting the grave dentry */ | |
259 | if (rep->d_parent != dir) { | |
260 | /* the entry was probably culled when we dropped the parent dir | |
261 | * lock */ | |
262 | unlock_rename(cache->graveyard, dir); | |
263 | _leave(" = 0 [culled?]"); | |
264 | return 0; | |
265 | } | |
266 | ||
267 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { | |
268 | unlock_rename(cache->graveyard, dir); | |
269 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
270 | return -EIO; | |
271 | } | |
272 | ||
273 | if (trap == rep) { | |
274 | unlock_rename(cache->graveyard, dir); | |
275 | cachefiles_io_error(cache, "May not make directory loop"); | |
276 | return -EIO; | |
277 | } | |
278 | ||
279 | if (d_mountpoint(rep)) { | |
280 | unlock_rename(cache->graveyard, dir); | |
281 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
282 | return -EIO; | |
283 | } | |
284 | ||
285 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
286 | if (IS_ERR(grave)) { | |
287 | unlock_rename(cache->graveyard, dir); | |
288 | ||
289 | if (PTR_ERR(grave) == -ENOMEM) { | |
290 | _leave(" = -ENOMEM"); | |
291 | return -ENOMEM; | |
292 | } | |
293 | ||
294 | cachefiles_io_error(cache, "Lookup error %ld", | |
295 | PTR_ERR(grave)); | |
296 | return -EIO; | |
297 | } | |
298 | ||
299 | if (grave->d_inode) { | |
300 | unlock_rename(cache->graveyard, dir); | |
301 | dput(grave); | |
302 | grave = NULL; | |
303 | cond_resched(); | |
304 | goto try_again; | |
305 | } | |
306 | ||
307 | if (d_mountpoint(grave)) { | |
308 | unlock_rename(cache->graveyard, dir); | |
309 | dput(grave); | |
310 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
311 | return -EIO; | |
312 | } | |
313 | ||
314 | /* target should not be an ancestor of source */ | |
315 | if (trap == grave) { | |
316 | unlock_rename(cache->graveyard, dir); | |
317 | dput(grave); | |
318 | cachefiles_io_error(cache, "May not make directory loop"); | |
319 | return -EIO; | |
320 | } | |
321 | ||
322 | /* attempt the rename */ | |
323 | ret = vfs_rename(dir->d_inode, rep, cache->graveyard->d_inode, grave); | |
324 | if (ret != 0 && ret != -ENOMEM) | |
325 | cachefiles_io_error(cache, "Rename failed with error %d", ret); | |
326 | ||
327 | unlock_rename(cache->graveyard, dir); | |
328 | dput(grave); | |
329 | _leave(" = 0"); | |
330 | return 0; | |
331 | } | |
332 | ||
333 | /* | |
334 | * delete an object representation from the cache | |
335 | */ | |
336 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
337 | struct cachefiles_object *object) | |
338 | { | |
339 | struct dentry *dir; | |
340 | int ret; | |
341 | ||
342 | _enter(",{%p}", object->dentry); | |
343 | ||
344 | ASSERT(object->dentry); | |
345 | ASSERT(object->dentry->d_inode); | |
346 | ASSERT(object->dentry->d_parent); | |
347 | ||
348 | dir = dget_parent(object->dentry); | |
349 | ||
6511de33 | 350 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae DH |
351 | |
352 | /* we need to check that our parent is _still_ our parent - it may have | |
353 | * been renamed */ | |
354 | if (dir == object->dentry->d_parent) { | |
355 | ret = cachefiles_bury_object(cache, dir, object->dentry); | |
356 | } else { | |
357 | /* it got moved, presumably by cachefilesd culling it, so it's | |
358 | * no longer in the key path and we can ignore it */ | |
359 | mutex_unlock(&dir->d_inode->i_mutex); | |
360 | ret = 0; | |
361 | } | |
9ae326a6 DH |
362 | |
363 | dput(dir); | |
364 | _leave(" = %d", ret); | |
365 | return ret; | |
366 | } | |
367 | ||
368 | /* | |
369 | * walk from the parent object to the child object through the backing | |
370 | * filesystem, creating directories as we go | |
371 | */ | |
372 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
373 | struct cachefiles_object *object, | |
374 | const char *key, | |
375 | struct cachefiles_xattr *auxdata) | |
376 | { | |
377 | struct cachefiles_cache *cache; | |
378 | struct dentry *dir, *next = NULL; | |
379 | unsigned long start; | |
380 | const char *name; | |
381 | int ret, nlen; | |
382 | ||
383 | _enter("{%p},,%s,", parent->dentry, key); | |
384 | ||
385 | cache = container_of(parent->fscache.cache, | |
386 | struct cachefiles_cache, cache); | |
387 | ||
388 | ASSERT(parent->dentry); | |
389 | ASSERT(parent->dentry->d_inode); | |
390 | ||
391 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { | |
392 | // TODO: convert file to dir | |
393 | _leave("looking up in none directory"); | |
394 | return -ENOBUFS; | |
395 | } | |
396 | ||
397 | dir = dget(parent->dentry); | |
398 | ||
399 | advance: | |
400 | /* attempt to transit the first directory component */ | |
401 | name = key; | |
402 | nlen = strlen(key); | |
403 | ||
404 | /* key ends in a double NUL */ | |
405 | key = key + nlen + 1; | |
406 | if (!*key) | |
407 | key = NULL; | |
408 | ||
409 | lookup_again: | |
410 | /* search the current directory for the element name */ | |
411 | _debug("lookup '%s'", name); | |
412 | ||
6511de33 | 413 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
414 | |
415 | start = jiffies; | |
416 | next = lookup_one_len(name, dir, nlen); | |
417 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
418 | if (IS_ERR(next)) | |
419 | goto lookup_error; | |
420 | ||
421 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); | |
422 | ||
423 | if (!key) | |
424 | object->new = !next->d_inode; | |
425 | ||
426 | /* if this element of the path doesn't exist, then the lookup phase | |
427 | * failed, and we can release any readers in the certain knowledge that | |
428 | * there's nothing for them to actually read */ | |
429 | if (!next->d_inode) | |
430 | fscache_object_lookup_negative(&object->fscache); | |
431 | ||
432 | /* we need to create the object if it's negative */ | |
433 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
434 | /* index objects and intervening tree levels must be subdirs */ | |
435 | if (!next->d_inode) { | |
436 | ret = cachefiles_has_space(cache, 1, 0); | |
437 | if (ret < 0) | |
438 | goto create_error; | |
439 | ||
440 | start = jiffies; | |
441 | ret = vfs_mkdir(dir->d_inode, next, 0); | |
442 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
443 | if (ret < 0) | |
444 | goto create_error; | |
445 | ||
446 | ASSERT(next->d_inode); | |
447 | ||
448 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
449 | next, next->d_inode, next->d_inode->i_ino); | |
450 | ||
451 | } else if (!S_ISDIR(next->d_inode->i_mode)) { | |
452 | kerror("inode %lu is not a directory", | |
453 | next->d_inode->i_ino); | |
454 | ret = -ENOBUFS; | |
455 | goto error; | |
456 | } | |
457 | ||
458 | } else { | |
459 | /* non-index objects start out life as files */ | |
460 | if (!next->d_inode) { | |
461 | ret = cachefiles_has_space(cache, 1, 0); | |
462 | if (ret < 0) | |
463 | goto create_error; | |
464 | ||
465 | start = jiffies; | |
466 | ret = vfs_create(dir->d_inode, next, S_IFREG, NULL); | |
467 | cachefiles_hist(cachefiles_create_histogram, start); | |
468 | if (ret < 0) | |
469 | goto create_error; | |
470 | ||
471 | ASSERT(next->d_inode); | |
472 | ||
473 | _debug("create -> %p{%p{ino=%lu}}", | |
474 | next, next->d_inode, next->d_inode->i_ino); | |
475 | ||
476 | } else if (!S_ISDIR(next->d_inode->i_mode) && | |
477 | !S_ISREG(next->d_inode->i_mode) | |
478 | ) { | |
479 | kerror("inode %lu is not a file or directory", | |
480 | next->d_inode->i_ino); | |
481 | ret = -ENOBUFS; | |
482 | goto error; | |
483 | } | |
484 | } | |
485 | ||
486 | /* process the next component */ | |
487 | if (key) { | |
488 | _debug("advance"); | |
489 | mutex_unlock(&dir->d_inode->i_mutex); | |
490 | dput(dir); | |
491 | dir = next; | |
492 | next = NULL; | |
493 | goto advance; | |
494 | } | |
495 | ||
496 | /* we've found the object we were looking for */ | |
497 | object->dentry = next; | |
498 | ||
499 | /* if we've found that the terminal object exists, then we need to | |
500 | * check its attributes and delete it if it's out of date */ | |
501 | if (!object->new) { | |
502 | _debug("validate '%*.*s'", | |
503 | next->d_name.len, next->d_name.len, next->d_name.name); | |
504 | ||
505 | ret = cachefiles_check_object_xattr(object, auxdata); | |
506 | if (ret == -ESTALE) { | |
507 | /* delete the object (the deleter drops the directory | |
508 | * mutex) */ | |
509 | object->dentry = NULL; | |
510 | ||
511 | ret = cachefiles_bury_object(cache, dir, next); | |
512 | dput(next); | |
513 | next = NULL; | |
514 | ||
515 | if (ret < 0) | |
516 | goto delete_error; | |
517 | ||
518 | _debug("redo lookup"); | |
519 | goto lookup_again; | |
520 | } | |
521 | } | |
522 | ||
523 | /* note that we're now using this object */ | |
fee096de | 524 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
525 | |
526 | mutex_unlock(&dir->d_inode->i_mutex); | |
527 | dput(dir); | |
528 | dir = NULL; | |
529 | ||
fee096de DH |
530 | if (ret == -ETIMEDOUT) |
531 | goto mark_active_timed_out; | |
532 | ||
9ae326a6 DH |
533 | _debug("=== OBTAINED_OBJECT ==="); |
534 | ||
535 | if (object->new) { | |
536 | /* attach data to a newly constructed terminal object */ | |
537 | ret = cachefiles_set_object_xattr(object, auxdata); | |
538 | if (ret < 0) | |
539 | goto check_error; | |
540 | } else { | |
541 | /* always update the atime on an object we've just looked up | |
542 | * (this is used to keep track of culling, and atimes are only | |
543 | * updated by read, write and readdir but not lookup or | |
544 | * open) */ | |
545 | touch_atime(cache->mnt, next); | |
546 | } | |
547 | ||
548 | /* open a file interface onto a data file */ | |
549 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
550 | if (S_ISREG(object->dentry->d_inode->i_mode)) { | |
551 | const struct address_space_operations *aops; | |
552 | ||
553 | ret = -EPERM; | |
554 | aops = object->dentry->d_inode->i_mapping->a_ops; | |
555 | if (!aops->bmap) | |
556 | goto check_error; | |
557 | ||
558 | object->backer = object->dentry; | |
559 | } else { | |
560 | BUG(); // TODO: open file in data-class subdir | |
561 | } | |
562 | } | |
563 | ||
564 | object->new = 0; | |
565 | fscache_obtained_object(&object->fscache); | |
566 | ||
567 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); | |
568 | return 0; | |
569 | ||
570 | create_error: | |
571 | _debug("create error %d", ret); | |
572 | if (ret == -EIO) | |
573 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
574 | goto error; | |
575 | ||
fee096de DH |
576 | mark_active_timed_out: |
577 | _debug("mark active timed out"); | |
578 | goto release_dentry; | |
579 | ||
9ae326a6 DH |
580 | check_error: |
581 | _debug("check error %d", ret); | |
582 | write_lock(&cache->active_lock); | |
583 | rb_erase(&object->active_node, &cache->active_nodes); | |
584 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
585 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
586 | write_unlock(&cache->active_lock); | |
fee096de | 587 | release_dentry: |
9ae326a6 DH |
588 | dput(object->dentry); |
589 | object->dentry = NULL; | |
590 | goto error_out; | |
591 | ||
592 | delete_error: | |
593 | _debug("delete error %d", ret); | |
594 | goto error_out2; | |
595 | ||
596 | lookup_error: | |
597 | _debug("lookup error %ld", PTR_ERR(next)); | |
598 | ret = PTR_ERR(next); | |
599 | if (ret == -EIO) | |
600 | cachefiles_io_error(cache, "Lookup failed"); | |
601 | next = NULL; | |
602 | error: | |
603 | mutex_unlock(&dir->d_inode->i_mutex); | |
604 | dput(next); | |
605 | error_out2: | |
606 | dput(dir); | |
607 | error_out: | |
9ae326a6 DH |
608 | _leave(" = error %d", -ret); |
609 | return ret; | |
610 | } | |
611 | ||
612 | /* | |
613 | * get a subdirectory | |
614 | */ | |
615 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
616 | struct dentry *dir, | |
617 | const char *dirname) | |
618 | { | |
619 | struct dentry *subdir; | |
620 | unsigned long start; | |
621 | int ret; | |
622 | ||
623 | _enter(",,%s", dirname); | |
624 | ||
625 | /* search the current directory for the element name */ | |
626 | mutex_lock(&dir->d_inode->i_mutex); | |
627 | ||
628 | start = jiffies; | |
629 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
630 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
631 | if (IS_ERR(subdir)) { | |
632 | if (PTR_ERR(subdir) == -ENOMEM) | |
633 | goto nomem_d_alloc; | |
634 | goto lookup_error; | |
635 | } | |
636 | ||
637 | _debug("subdir -> %p %s", | |
638 | subdir, subdir->d_inode ? "positive" : "negative"); | |
639 | ||
640 | /* we need to create the subdir if it doesn't exist yet */ | |
641 | if (!subdir->d_inode) { | |
642 | ret = cachefiles_has_space(cache, 1, 0); | |
643 | if (ret < 0) | |
644 | goto mkdir_error; | |
645 | ||
646 | _debug("attempt mkdir"); | |
647 | ||
648 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); | |
649 | if (ret < 0) | |
650 | goto mkdir_error; | |
651 | ||
652 | ASSERT(subdir->d_inode); | |
653 | ||
654 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
655 | subdir, | |
656 | subdir->d_inode, | |
657 | subdir->d_inode->i_ino); | |
658 | } | |
659 | ||
660 | mutex_unlock(&dir->d_inode->i_mutex); | |
661 | ||
662 | /* we need to make sure the subdir is a directory */ | |
663 | ASSERT(subdir->d_inode); | |
664 | ||
665 | if (!S_ISDIR(subdir->d_inode->i_mode)) { | |
666 | kerror("%s is not a directory", dirname); | |
667 | ret = -EIO; | |
668 | goto check_error; | |
669 | } | |
670 | ||
671 | ret = -EPERM; | |
672 | if (!subdir->d_inode->i_op || | |
673 | !subdir->d_inode->i_op->setxattr || | |
674 | !subdir->d_inode->i_op->getxattr || | |
675 | !subdir->d_inode->i_op->lookup || | |
676 | !subdir->d_inode->i_op->mkdir || | |
677 | !subdir->d_inode->i_op->create || | |
678 | !subdir->d_inode->i_op->rename || | |
679 | !subdir->d_inode->i_op->rmdir || | |
680 | !subdir->d_inode->i_op->unlink) | |
681 | goto check_error; | |
682 | ||
683 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
684 | return subdir; | |
685 | ||
686 | check_error: | |
687 | dput(subdir); | |
688 | _leave(" = %d [check]", ret); | |
689 | return ERR_PTR(ret); | |
690 | ||
691 | mkdir_error: | |
692 | mutex_unlock(&dir->d_inode->i_mutex); | |
693 | dput(subdir); | |
694 | kerror("mkdir %s failed with error %d", dirname, ret); | |
695 | return ERR_PTR(ret); | |
696 | ||
697 | lookup_error: | |
698 | mutex_unlock(&dir->d_inode->i_mutex); | |
699 | ret = PTR_ERR(subdir); | |
700 | kerror("Lookup %s failed with error %d", dirname, ret); | |
701 | return ERR_PTR(ret); | |
702 | ||
703 | nomem_d_alloc: | |
704 | mutex_unlock(&dir->d_inode->i_mutex); | |
705 | _leave(" = -ENOMEM"); | |
706 | return ERR_PTR(-ENOMEM); | |
707 | } | |
708 | ||
709 | /* | |
710 | * find out if an object is in use or not | |
711 | * - if finds object and it's not in use: | |
712 | * - returns a pointer to the object and a reference on it | |
713 | * - returns with the directory locked | |
714 | */ | |
715 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
716 | struct dentry *dir, | |
717 | char *filename) | |
718 | { | |
719 | struct cachefiles_object *object; | |
720 | struct rb_node *_n; | |
721 | struct dentry *victim; | |
722 | unsigned long start; | |
723 | int ret; | |
724 | ||
725 | //_enter(",%*.*s/,%s", | |
726 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
727 | ||
728 | /* look up the victim */ | |
729 | mutex_lock_nested(&dir->d_inode->i_mutex, 1); | |
730 | ||
731 | start = jiffies; | |
732 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
733 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
734 | if (IS_ERR(victim)) | |
735 | goto lookup_error; | |
736 | ||
737 | //_debug("victim -> %p %s", | |
738 | // victim, victim->d_inode ? "positive" : "negative"); | |
739 | ||
740 | /* if the object is no longer there then we probably retired the object | |
741 | * at the netfs's request whilst the cull was in progress | |
742 | */ | |
743 | if (!victim->d_inode) { | |
744 | mutex_unlock(&dir->d_inode->i_mutex); | |
745 | dput(victim); | |
746 | _leave(" = -ENOENT [absent]"); | |
747 | return ERR_PTR(-ENOENT); | |
748 | } | |
749 | ||
750 | /* check to see if we're using this object */ | |
751 | read_lock(&cache->active_lock); | |
752 | ||
753 | _n = cache->active_nodes.rb_node; | |
754 | ||
755 | while (_n) { | |
756 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
757 | ||
758 | if (object->dentry > victim) | |
759 | _n = _n->rb_left; | |
760 | else if (object->dentry < victim) | |
761 | _n = _n->rb_right; | |
762 | else | |
763 | goto object_in_use; | |
764 | } | |
765 | ||
766 | read_unlock(&cache->active_lock); | |
767 | ||
768 | //_leave(" = %p", victim); | |
769 | return victim; | |
770 | ||
771 | object_in_use: | |
772 | read_unlock(&cache->active_lock); | |
773 | mutex_unlock(&dir->d_inode->i_mutex); | |
774 | dput(victim); | |
775 | //_leave(" = -EBUSY [in use]"); | |
776 | return ERR_PTR(-EBUSY); | |
777 | ||
778 | lookup_error: | |
779 | mutex_unlock(&dir->d_inode->i_mutex); | |
780 | ret = PTR_ERR(victim); | |
781 | if (ret == -ENOENT) { | |
782 | /* file or dir now absent - probably retired by netfs */ | |
783 | _leave(" = -ESTALE [absent]"); | |
784 | return ERR_PTR(-ESTALE); | |
785 | } | |
786 | ||
787 | if (ret == -EIO) { | |
788 | cachefiles_io_error(cache, "Lookup failed"); | |
789 | } else if (ret != -ENOMEM) { | |
790 | kerror("Internal error: %d", ret); | |
791 | ret = -EIO; | |
792 | } | |
793 | ||
794 | _leave(" = %d", ret); | |
795 | return ERR_PTR(ret); | |
796 | } | |
797 | ||
798 | /* | |
799 | * cull an object if it's not in use | |
800 | * - called only by cache manager daemon | |
801 | */ | |
802 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
803 | char *filename) | |
804 | { | |
805 | struct dentry *victim; | |
806 | int ret; | |
807 | ||
808 | _enter(",%*.*s/,%s", | |
809 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
810 | ||
811 | victim = cachefiles_check_active(cache, dir, filename); | |
812 | if (IS_ERR(victim)) | |
813 | return PTR_ERR(victim); | |
814 | ||
815 | _debug("victim -> %p %s", | |
816 | victim, victim->d_inode ? "positive" : "negative"); | |
817 | ||
818 | /* okay... the victim is not being used so we can cull it | |
819 | * - start by marking it as stale | |
820 | */ | |
821 | _debug("victim is cullable"); | |
822 | ||
823 | ret = cachefiles_remove_object_xattr(cache, victim); | |
824 | if (ret < 0) | |
825 | goto error_unlock; | |
826 | ||
827 | /* actually remove the victim (drops the dir mutex) */ | |
828 | _debug("bury"); | |
829 | ||
830 | ret = cachefiles_bury_object(cache, dir, victim); | |
831 | if (ret < 0) | |
832 | goto error; | |
833 | ||
834 | dput(victim); | |
835 | _leave(" = 0"); | |
836 | return 0; | |
837 | ||
838 | error_unlock: | |
839 | mutex_unlock(&dir->d_inode->i_mutex); | |
840 | error: | |
841 | dput(victim); | |
842 | if (ret == -ENOENT) { | |
843 | /* file or dir now absent - probably retired by netfs */ | |
844 | _leave(" = -ESTALE [absent]"); | |
845 | return -ESTALE; | |
846 | } | |
847 | ||
848 | if (ret != -ENOMEM) { | |
849 | kerror("Internal error: %d", ret); | |
850 | ret = -EIO; | |
851 | } | |
852 | ||
853 | _leave(" = %d", ret); | |
854 | return ret; | |
855 | } | |
856 | ||
857 | /* | |
858 | * find out if an object is in use or not | |
859 | * - called only by cache manager daemon | |
860 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
861 | */ | |
862 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
863 | char *filename) | |
864 | { | |
865 | struct dentry *victim; | |
866 | ||
867 | //_enter(",%*.*s/,%s", | |
868 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
869 | ||
870 | victim = cachefiles_check_active(cache, dir, filename); | |
871 | if (IS_ERR(victim)) | |
872 | return PTR_ERR(victim); | |
873 | ||
874 | mutex_unlock(&dir->d_inode->i_mutex); | |
875 | dput(victim); | |
876 | //_leave(" = 0"); | |
877 | return 0; | |
878 | } |