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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 <linux/slab.h> |
23 | #include "internal.h" |
24 | |
25 | #define CACHEFILES_KEYBUF_SIZE 512 |
26 | |
27 | /* |
28 | * dump debugging info about an object |
29 | */ |
30 | static noinline |
31 | void __cachefiles_printk_object(struct cachefiles_object *object, |
32 | const char *prefix, |
33 | u8 *keybuf) |
34 | { |
35 | struct fscache_cookie *cookie; |
36 | unsigned keylen, loop; |
37 | |
38 | printk(KERN_ERR "%sobject: OBJ%x\n", |
39 | prefix, object->fscache.debug_id); |
40 | printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", |
41 | prefix, fscache_object_states[object->fscache.state], |
42 | object->fscache.flags, work_busy(&object->fscache.work), |
43 | object->fscache.events, |
44 | object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK); |
45 | printk(KERN_ERR "%sops=%u inp=%u exc=%u\n", |
46 | prefix, object->fscache.n_ops, object->fscache.n_in_progress, |
47 | object->fscache.n_exclusive); |
48 | printk(KERN_ERR "%sparent=%p\n", |
49 | prefix, object->fscache.parent); |
50 | |
51 | spin_lock(&object->fscache.lock); |
52 | cookie = object->fscache.cookie; |
53 | if (cookie) { |
54 | printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n", |
55 | prefix, |
56 | object->fscache.cookie, |
57 | object->fscache.cookie->parent, |
58 | object->fscache.cookie->netfs_data, |
59 | object->fscache.cookie->flags); |
60 | if (keybuf) |
61 | keylen = cookie->def->get_key(cookie->netfs_data, keybuf, |
62 | CACHEFILES_KEYBUF_SIZE); |
63 | else |
64 | keylen = 0; |
65 | } else { |
66 | printk(KERN_ERR "%scookie=NULL\n", prefix); |
67 | keylen = 0; |
68 | } |
69 | spin_unlock(&object->fscache.lock); |
70 | |
71 | if (keylen) { |
72 | printk(KERN_ERR "%skey=[%u] '", prefix, keylen); |
73 | for (loop = 0; loop < keylen; loop++) |
74 | printk("%02x", keybuf[loop]); |
75 | printk("'\n"); |
76 | } |
77 | } |
78 | |
79 | /* |
80 | * dump debugging info about a pair of objects |
81 | */ |
82 | static noinline void cachefiles_printk_object(struct cachefiles_object *object, |
83 | struct cachefiles_object *xobject) |
84 | { |
85 | u8 *keybuf; |
86 | |
87 | keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); |
88 | if (object) |
89 | __cachefiles_printk_object(object, "", keybuf); |
90 | if (xobject) |
91 | __cachefiles_printk_object(xobject, "x", keybuf); |
92 | kfree(keybuf); |
93 | } |
94 | |
95 | /* |
96 | * mark the owner of a dentry, if there is one, to indicate that that dentry |
97 | * has been preemptively deleted |
98 | * - the caller must hold the i_mutex on the dentry's parent as required to |
99 | * call vfs_unlink(), vfs_rmdir() or vfs_rename() |
100 | */ |
101 | static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, |
102 | struct dentry *dentry) |
103 | { |
104 | struct cachefiles_object *object; |
105 | struct rb_node *p; |
106 | |
107 | _enter(",'%*.*s'", |
108 | dentry->d_name.len, dentry->d_name.len, dentry->d_name.name); |
109 | |
110 | write_lock(&cache->active_lock); |
111 | |
112 | p = cache->active_nodes.rb_node; |
113 | while (p) { |
114 | object = rb_entry(p, struct cachefiles_object, active_node); |
115 | if (object->dentry > dentry) |
116 | p = p->rb_left; |
117 | else if (object->dentry < dentry) |
118 | p = p->rb_right; |
119 | else |
120 | goto found_dentry; |
121 | } |
122 | |
123 | write_unlock(&cache->active_lock); |
124 | _leave(" [no owner]"); |
125 | return; |
126 | |
127 | /* found the dentry for */ |
128 | found_dentry: |
129 | kdebug("preemptive burial: OBJ%x [%s] %p", |
130 | object->fscache.debug_id, |
131 | fscache_object_states[object->fscache.state], |
132 | dentry); |
133 | |
134 | if (object->fscache.state < FSCACHE_OBJECT_DYING) { |
135 | printk(KERN_ERR "\n"); |
136 | printk(KERN_ERR "CacheFiles: Error:" |
137 | " Can't preemptively bury live object\n"); |
138 | cachefiles_printk_object(object, NULL); |
139 | } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { |
140 | printk(KERN_ERR "CacheFiles: Error:" |
141 | " Object already preemptively buried\n"); |
142 | } |
143 | |
144 | write_unlock(&cache->active_lock); |
145 | _leave(" [owner marked]"); |
146 | } |
147 | |
148 | /* |
149 | * record the fact that an object is now active |
150 | */ |
151 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
152 | struct cachefiles_object *object) |
153 | { |
154 | struct cachefiles_object *xobject; |
155 | struct rb_node **_p, *_parent = NULL; |
156 | struct dentry *dentry; |
157 | |
158 | _enter(",%p", object); |
159 | |
160 | try_again: |
161 | write_lock(&cache->active_lock); |
162 | |
163 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
164 | printk(KERN_ERR "CacheFiles: Error: Object already active\n"); |
165 | cachefiles_printk_object(object, NULL); |
166 | BUG(); |
167 | } |
168 | |
169 | dentry = object->dentry; |
170 | _p = &cache->active_nodes.rb_node; |
171 | while (*_p) { |
172 | _parent = *_p; |
173 | xobject = rb_entry(_parent, |
174 | struct cachefiles_object, active_node); |
175 | |
176 | ASSERT(xobject != object); |
177 | |
178 | if (xobject->dentry > dentry) |
179 | _p = &(*_p)->rb_left; |
180 | else if (xobject->dentry < dentry) |
181 | _p = &(*_p)->rb_right; |
182 | else |
183 | goto wait_for_old_object; |
184 | } |
185 | |
186 | rb_link_node(&object->active_node, _parent, _p); |
187 | rb_insert_color(&object->active_node, &cache->active_nodes); |
188 | |
189 | write_unlock(&cache->active_lock); |
190 | _leave(" = 0"); |
191 | return 0; |
192 | |
193 | /* an old object from a previous incarnation is hogging the slot - we |
194 | * need to wait for it to be destroyed */ |
195 | wait_for_old_object: |
196 | if (xobject->fscache.state < FSCACHE_OBJECT_DYING) { |
197 | printk(KERN_ERR "\n"); |
198 | printk(KERN_ERR "CacheFiles: Error:" |
199 | " Unexpected object collision\n"); |
200 | cachefiles_printk_object(object, xobject); |
201 | BUG(); |
202 | } |
203 | atomic_inc(&xobject->usage); |
204 | write_unlock(&cache->active_lock); |
205 | |
206 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
207 | wait_queue_head_t *wq; |
208 | |
209 | signed long timeout = 60 * HZ; |
210 | wait_queue_t wait; |
211 | bool requeue; |
212 | |
213 | /* if the object we're waiting for is queued for processing, |
214 | * then just put ourselves on the queue behind it */ |
215 | if (work_pending(&xobject->fscache.work)) { |
216 | _debug("queue OBJ%x behind OBJ%x immediately", |
217 | object->fscache.debug_id, |
218 | xobject->fscache.debug_id); |
219 | goto requeue; |
220 | } |
221 | |
222 | /* otherwise we sleep until either the object we're waiting for |
223 | * is done, or the fscache_object is congested */ |
224 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); |
225 | init_wait(&wait); |
226 | requeue = false; |
227 | do { |
228 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); |
229 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) |
230 | break; |
231 | |
232 | requeue = fscache_object_sleep_till_congested(&timeout); |
233 | } while (timeout > 0 && !requeue); |
234 | finish_wait(wq, &wait); |
235 | |
236 | if (requeue && |
237 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
238 | _debug("queue OBJ%x behind OBJ%x after wait", |
239 | object->fscache.debug_id, |
240 | xobject->fscache.debug_id); |
241 | goto requeue; |
242 | } |
243 | |
244 | if (timeout <= 0) { |
245 | printk(KERN_ERR "\n"); |
246 | printk(KERN_ERR "CacheFiles: Error: Overlong" |
247 | " wait for old active object to go away\n"); |
248 | cachefiles_printk_object(object, xobject); |
249 | goto requeue; |
250 | } |
251 | } |
252 | |
253 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); |
254 | |
255 | cache->cache.ops->put_object(&xobject->fscache); |
256 | goto try_again; |
257 | |
258 | requeue: |
259 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); |
260 | cache->cache.ops->put_object(&xobject->fscache); |
261 | _leave(" = -ETIMEDOUT"); |
262 | return -ETIMEDOUT; |
263 | } |
264 | |
265 | /* |
266 | * delete an object representation from the cache |
267 | * - file backed objects are unlinked |
268 | * - directory backed objects are stuffed into the graveyard for userspace to |
269 | * delete |
270 | * - unlocks the directory mutex |
271 | */ |
272 | static int cachefiles_bury_object(struct cachefiles_cache *cache, |
273 | struct dentry *dir, |
274 | struct dentry *rep, |
275 | bool preemptive) |
276 | { |
277 | struct dentry *grave, *trap; |
278 | struct path path, path_to_graveyard; |
279 | char nbuffer[8 + 8 + 1]; |
280 | int ret; |
281 | |
282 | _enter(",'%*.*s','%*.*s'", |
283 | dir->d_name.len, dir->d_name.len, dir->d_name.name, |
284 | rep->d_name.len, rep->d_name.len, rep->d_name.name); |
285 | |
286 | _debug("remove %p from %p", rep, dir); |
287 | |
288 | /* non-directories can just be unlinked */ |
289 | if (!S_ISDIR(rep->d_inode->i_mode)) { |
290 | _debug("unlink stale object"); |
291 | |
292 | path.mnt = cache->mnt; |
293 | path.dentry = dir; |
294 | ret = security_path_unlink(&path, rep); |
295 | if (ret < 0) { |
296 | cachefiles_io_error(cache, "Unlink security error"); |
297 | } else { |
298 | ret = vfs_unlink(dir->d_inode, rep); |
299 | |
300 | if (preemptive) |
301 | cachefiles_mark_object_buried(cache, rep); |
302 | } |
303 | |
304 | mutex_unlock(&dir->d_inode->i_mutex); |
305 | |
306 | if (ret == -EIO) |
307 | cachefiles_io_error(cache, "Unlink failed"); |
308 | |
309 | _leave(" = %d", ret); |
310 | return ret; |
311 | } |
312 | |
313 | /* directories have to be moved to the graveyard */ |
314 | _debug("move stale object to graveyard"); |
315 | mutex_unlock(&dir->d_inode->i_mutex); |
316 | |
317 | try_again: |
318 | /* first step is to make up a grave dentry in the graveyard */ |
319 | sprintf(nbuffer, "%08x%08x", |
320 | (uint32_t) get_seconds(), |
321 | (uint32_t) atomic_inc_return(&cache->gravecounter)); |
322 | |
323 | /* do the multiway lock magic */ |
324 | trap = lock_rename(cache->graveyard, dir); |
325 | |
326 | /* do some checks before getting the grave dentry */ |
327 | if (rep->d_parent != dir) { |
328 | /* the entry was probably culled when we dropped the parent dir |
329 | * lock */ |
330 | unlock_rename(cache->graveyard, dir); |
331 | _leave(" = 0 [culled?]"); |
332 | return 0; |
333 | } |
334 | |
335 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { |
336 | unlock_rename(cache->graveyard, dir); |
337 | cachefiles_io_error(cache, "Graveyard no longer a directory"); |
338 | return -EIO; |
339 | } |
340 | |
341 | if (trap == rep) { |
342 | unlock_rename(cache->graveyard, dir); |
343 | cachefiles_io_error(cache, "May not make directory loop"); |
344 | return -EIO; |
345 | } |
346 | |
347 | if (d_mountpoint(rep)) { |
348 | unlock_rename(cache->graveyard, dir); |
349 | cachefiles_io_error(cache, "Mountpoint in cache"); |
350 | return -EIO; |
351 | } |
352 | |
353 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); |
354 | if (IS_ERR(grave)) { |
355 | unlock_rename(cache->graveyard, dir); |
356 | |
357 | if (PTR_ERR(grave) == -ENOMEM) { |
358 | _leave(" = -ENOMEM"); |
359 | return -ENOMEM; |
360 | } |
361 | |
362 | cachefiles_io_error(cache, "Lookup error %ld", |
363 | PTR_ERR(grave)); |
364 | return -EIO; |
365 | } |
366 | |
367 | if (grave->d_inode) { |
368 | unlock_rename(cache->graveyard, dir); |
369 | dput(grave); |
370 | grave = NULL; |
371 | cond_resched(); |
372 | goto try_again; |
373 | } |
374 | |
375 | if (d_mountpoint(grave)) { |
376 | unlock_rename(cache->graveyard, dir); |
377 | dput(grave); |
378 | cachefiles_io_error(cache, "Mountpoint in graveyard"); |
379 | return -EIO; |
380 | } |
381 | |
382 | /* target should not be an ancestor of source */ |
383 | if (trap == grave) { |
384 | unlock_rename(cache->graveyard, dir); |
385 | dput(grave); |
386 | cachefiles_io_error(cache, "May not make directory loop"); |
387 | return -EIO; |
388 | } |
389 | |
390 | /* attempt the rename */ |
391 | path.mnt = cache->mnt; |
392 | path.dentry = dir; |
393 | path_to_graveyard.mnt = cache->mnt; |
394 | path_to_graveyard.dentry = cache->graveyard; |
395 | ret = security_path_rename(&path, rep, &path_to_graveyard, grave); |
396 | if (ret < 0) { |
397 | cachefiles_io_error(cache, "Rename security error %d", ret); |
398 | } else { |
399 | ret = vfs_rename(dir->d_inode, rep, |
400 | cache->graveyard->d_inode, grave); |
401 | if (ret != 0 && ret != -ENOMEM) |
402 | cachefiles_io_error(cache, |
403 | "Rename failed with error %d", ret); |
404 | |
405 | if (preemptive) |
406 | cachefiles_mark_object_buried(cache, rep); |
407 | } |
408 | |
409 | unlock_rename(cache->graveyard, dir); |
410 | dput(grave); |
411 | _leave(" = 0"); |
412 | return 0; |
413 | } |
414 | |
415 | /* |
416 | * delete an object representation from the cache |
417 | */ |
418 | int cachefiles_delete_object(struct cachefiles_cache *cache, |
419 | struct cachefiles_object *object) |
420 | { |
421 | struct dentry *dir; |
422 | int ret; |
423 | |
424 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); |
425 | |
426 | ASSERT(object->dentry); |
427 | ASSERT(object->dentry->d_inode); |
428 | ASSERT(object->dentry->d_parent); |
429 | |
430 | dir = dget_parent(object->dentry); |
431 | |
432 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
433 | |
434 | if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { |
435 | /* object allocation for the same key preemptively deleted this |
436 | * object's file so that it could create its own file */ |
437 | _debug("object preemptively buried"); |
438 | mutex_unlock(&dir->d_inode->i_mutex); |
439 | ret = 0; |
440 | } else { |
441 | /* we need to check that our parent is _still_ our parent - it |
442 | * may have been renamed */ |
443 | if (dir == object->dentry->d_parent) { |
444 | ret = cachefiles_bury_object(cache, dir, |
445 | object->dentry, false); |
446 | } else { |
447 | /* it got moved, presumably by cachefilesd culling it, |
448 | * so it's no longer in the key path and we can ignore |
449 | * it */ |
450 | mutex_unlock(&dir->d_inode->i_mutex); |
451 | ret = 0; |
452 | } |
453 | } |
454 | |
455 | dput(dir); |
456 | _leave(" = %d", ret); |
457 | return ret; |
458 | } |
459 | |
460 | /* |
461 | * walk from the parent object to the child object through the backing |
462 | * filesystem, creating directories as we go |
463 | */ |
464 | int cachefiles_walk_to_object(struct cachefiles_object *parent, |
465 | struct cachefiles_object *object, |
466 | const char *key, |
467 | struct cachefiles_xattr *auxdata) |
468 | { |
469 | struct cachefiles_cache *cache; |
470 | struct dentry *dir, *next = NULL; |
471 | struct path path; |
472 | unsigned long start; |
473 | const char *name; |
474 | int ret, nlen; |
475 | |
476 | _enter("OBJ%x{%p},OBJ%x,%s,", |
477 | parent->fscache.debug_id, parent->dentry, |
478 | object->fscache.debug_id, key); |
479 | |
480 | cache = container_of(parent->fscache.cache, |
481 | struct cachefiles_cache, cache); |
482 | path.mnt = cache->mnt; |
483 | |
484 | ASSERT(parent->dentry); |
485 | ASSERT(parent->dentry->d_inode); |
486 | |
487 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { |
488 | // TODO: convert file to dir |
489 | _leave("looking up in none directory"); |
490 | return -ENOBUFS; |
491 | } |
492 | |
493 | dir = dget(parent->dentry); |
494 | |
495 | advance: |
496 | /* attempt to transit the first directory component */ |
497 | name = key; |
498 | nlen = strlen(key); |
499 | |
500 | /* key ends in a double NUL */ |
501 | key = key + nlen + 1; |
502 | if (!*key) |
503 | key = NULL; |
504 | |
505 | lookup_again: |
506 | /* search the current directory for the element name */ |
507 | _debug("lookup '%s'", name); |
508 | |
509 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
510 | |
511 | start = jiffies; |
512 | next = lookup_one_len(name, dir, nlen); |
513 | cachefiles_hist(cachefiles_lookup_histogram, start); |
514 | if (IS_ERR(next)) |
515 | goto lookup_error; |
516 | |
517 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); |
518 | |
519 | if (!key) |
520 | object->new = !next->d_inode; |
521 | |
522 | /* if this element of the path doesn't exist, then the lookup phase |
523 | * failed, and we can release any readers in the certain knowledge that |
524 | * there's nothing for them to actually read */ |
525 | if (!next->d_inode) |
526 | fscache_object_lookup_negative(&object->fscache); |
527 | |
528 | /* we need to create the object if it's negative */ |
529 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { |
530 | /* index objects and intervening tree levels must be subdirs */ |
531 | if (!next->d_inode) { |
532 | ret = cachefiles_has_space(cache, 1, 0); |
533 | if (ret < 0) |
534 | goto create_error; |
535 | |
536 | path.dentry = dir; |
537 | ret = security_path_mkdir(&path, next, 0); |
538 | if (ret < 0) |
539 | goto create_error; |
540 | start = jiffies; |
541 | ret = vfs_mkdir(dir->d_inode, next, 0); |
542 | cachefiles_hist(cachefiles_mkdir_histogram, start); |
543 | if (ret < 0) |
544 | goto create_error; |
545 | |
546 | ASSERT(next->d_inode); |
547 | |
548 | _debug("mkdir -> %p{%p{ino=%lu}}", |
549 | next, next->d_inode, next->d_inode->i_ino); |
550 | |
551 | } else if (!S_ISDIR(next->d_inode->i_mode)) { |
552 | kerror("inode %lu is not a directory", |
553 | next->d_inode->i_ino); |
554 | ret = -ENOBUFS; |
555 | goto error; |
556 | } |
557 | |
558 | } else { |
559 | /* non-index objects start out life as files */ |
560 | if (!next->d_inode) { |
561 | ret = cachefiles_has_space(cache, 1, 0); |
562 | if (ret < 0) |
563 | goto create_error; |
564 | |
565 | path.dentry = dir; |
566 | ret = security_path_mknod(&path, next, S_IFREG, 0); |
567 | if (ret < 0) |
568 | goto create_error; |
569 | start = jiffies; |
570 | ret = vfs_create(dir->d_inode, next, S_IFREG, NULL); |
571 | cachefiles_hist(cachefiles_create_histogram, start); |
572 | if (ret < 0) |
573 | goto create_error; |
574 | |
575 | ASSERT(next->d_inode); |
576 | |
577 | _debug("create -> %p{%p{ino=%lu}}", |
578 | next, next->d_inode, next->d_inode->i_ino); |
579 | |
580 | } else if (!S_ISDIR(next->d_inode->i_mode) && |
581 | !S_ISREG(next->d_inode->i_mode) |
582 | ) { |
583 | kerror("inode %lu is not a file or directory", |
584 | next->d_inode->i_ino); |
585 | ret = -ENOBUFS; |
586 | goto error; |
587 | } |
588 | } |
589 | |
590 | /* process the next component */ |
591 | if (key) { |
592 | _debug("advance"); |
593 | mutex_unlock(&dir->d_inode->i_mutex); |
594 | dput(dir); |
595 | dir = next; |
596 | next = NULL; |
597 | goto advance; |
598 | } |
599 | |
600 | /* we've found the object we were looking for */ |
601 | object->dentry = next; |
602 | |
603 | /* if we've found that the terminal object exists, then we need to |
604 | * check its attributes and delete it if it's out of date */ |
605 | if (!object->new) { |
606 | _debug("validate '%*.*s'", |
607 | next->d_name.len, next->d_name.len, next->d_name.name); |
608 | |
609 | ret = cachefiles_check_object_xattr(object, auxdata); |
610 | if (ret == -ESTALE) { |
611 | /* delete the object (the deleter drops the directory |
612 | * mutex) */ |
613 | object->dentry = NULL; |
614 | |
615 | ret = cachefiles_bury_object(cache, dir, next, true); |
616 | dput(next); |
617 | next = NULL; |
618 | |
619 | if (ret < 0) |
620 | goto delete_error; |
621 | |
622 | _debug("redo lookup"); |
623 | goto lookup_again; |
624 | } |
625 | } |
626 | |
627 | /* note that we're now using this object */ |
628 | ret = cachefiles_mark_object_active(cache, object); |
629 | |
630 | mutex_unlock(&dir->d_inode->i_mutex); |
631 | dput(dir); |
632 | dir = NULL; |
633 | |
634 | if (ret == -ETIMEDOUT) |
635 | goto mark_active_timed_out; |
636 | |
637 | _debug("=== OBTAINED_OBJECT ==="); |
638 | |
639 | if (object->new) { |
640 | /* attach data to a newly constructed terminal object */ |
641 | ret = cachefiles_set_object_xattr(object, auxdata); |
642 | if (ret < 0) |
643 | goto check_error; |
644 | } else { |
645 | /* always update the atime on an object we've just looked up |
646 | * (this is used to keep track of culling, and atimes are only |
647 | * updated by read, write and readdir but not lookup or |
648 | * open) */ |
649 | touch_atime(cache->mnt, next); |
650 | } |
651 | |
652 | /* open a file interface onto a data file */ |
653 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { |
654 | if (S_ISREG(object->dentry->d_inode->i_mode)) { |
655 | const struct address_space_operations *aops; |
656 | |
657 | ret = -EPERM; |
658 | aops = object->dentry->d_inode->i_mapping->a_ops; |
659 | if (!aops->bmap) |
660 | goto check_error; |
661 | |
662 | object->backer = object->dentry; |
663 | } else { |
664 | BUG(); // TODO: open file in data-class subdir |
665 | } |
666 | } |
667 | |
668 | object->new = 0; |
669 | fscache_obtained_object(&object->fscache); |
670 | |
671 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); |
672 | return 0; |
673 | |
674 | create_error: |
675 | _debug("create error %d", ret); |
676 | if (ret == -EIO) |
677 | cachefiles_io_error(cache, "Create/mkdir failed"); |
678 | goto error; |
679 | |
680 | mark_active_timed_out: |
681 | _debug("mark active timed out"); |
682 | goto release_dentry; |
683 | |
684 | check_error: |
685 | _debug("check error %d", ret); |
686 | write_lock(&cache->active_lock); |
687 | rb_erase(&object->active_node, &cache->active_nodes); |
688 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); |
689 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); |
690 | write_unlock(&cache->active_lock); |
691 | release_dentry: |
692 | dput(object->dentry); |
693 | object->dentry = NULL; |
694 | goto error_out; |
695 | |
696 | delete_error: |
697 | _debug("delete error %d", ret); |
698 | goto error_out2; |
699 | |
700 | lookup_error: |
701 | _debug("lookup error %ld", PTR_ERR(next)); |
702 | ret = PTR_ERR(next); |
703 | if (ret == -EIO) |
704 | cachefiles_io_error(cache, "Lookup failed"); |
705 | next = NULL; |
706 | error: |
707 | mutex_unlock(&dir->d_inode->i_mutex); |
708 | dput(next); |
709 | error_out2: |
710 | dput(dir); |
711 | error_out: |
712 | _leave(" = error %d", -ret); |
713 | return ret; |
714 | } |
715 | |
716 | /* |
717 | * get a subdirectory |
718 | */ |
719 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, |
720 | struct dentry *dir, |
721 | const char *dirname) |
722 | { |
723 | struct dentry *subdir; |
724 | unsigned long start; |
725 | struct path path; |
726 | int ret; |
727 | |
728 | _enter(",,%s", dirname); |
729 | |
730 | /* search the current directory for the element name */ |
731 | mutex_lock(&dir->d_inode->i_mutex); |
732 | |
733 | start = jiffies; |
734 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); |
735 | cachefiles_hist(cachefiles_lookup_histogram, start); |
736 | if (IS_ERR(subdir)) { |
737 | if (PTR_ERR(subdir) == -ENOMEM) |
738 | goto nomem_d_alloc; |
739 | goto lookup_error; |
740 | } |
741 | |
742 | _debug("subdir -> %p %s", |
743 | subdir, subdir->d_inode ? "positive" : "negative"); |
744 | |
745 | /* we need to create the subdir if it doesn't exist yet */ |
746 | if (!subdir->d_inode) { |
747 | ret = cachefiles_has_space(cache, 1, 0); |
748 | if (ret < 0) |
749 | goto mkdir_error; |
750 | |
751 | _debug("attempt mkdir"); |
752 | |
753 | path.mnt = cache->mnt; |
754 | path.dentry = dir; |
755 | ret = security_path_mkdir(&path, subdir, 0700); |
756 | if (ret < 0) |
757 | goto mkdir_error; |
758 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); |
759 | if (ret < 0) |
760 | goto mkdir_error; |
761 | |
762 | ASSERT(subdir->d_inode); |
763 | |
764 | _debug("mkdir -> %p{%p{ino=%lu}}", |
765 | subdir, |
766 | subdir->d_inode, |
767 | subdir->d_inode->i_ino); |
768 | } |
769 | |
770 | mutex_unlock(&dir->d_inode->i_mutex); |
771 | |
772 | /* we need to make sure the subdir is a directory */ |
773 | ASSERT(subdir->d_inode); |
774 | |
775 | if (!S_ISDIR(subdir->d_inode->i_mode)) { |
776 | kerror("%s is not a directory", dirname); |
777 | ret = -EIO; |
778 | goto check_error; |
779 | } |
780 | |
781 | ret = -EPERM; |
782 | if (!subdir->d_inode->i_op || |
783 | !subdir->d_inode->i_op->setxattr || |
784 | !subdir->d_inode->i_op->getxattr || |
785 | !subdir->d_inode->i_op->lookup || |
786 | !subdir->d_inode->i_op->mkdir || |
787 | !subdir->d_inode->i_op->create || |
788 | !subdir->d_inode->i_op->rename || |
789 | !subdir->d_inode->i_op->rmdir || |
790 | !subdir->d_inode->i_op->unlink) |
791 | goto check_error; |
792 | |
793 | _leave(" = [%lu]", subdir->d_inode->i_ino); |
794 | return subdir; |
795 | |
796 | check_error: |
797 | dput(subdir); |
798 | _leave(" = %d [check]", ret); |
799 | return ERR_PTR(ret); |
800 | |
801 | mkdir_error: |
802 | mutex_unlock(&dir->d_inode->i_mutex); |
803 | dput(subdir); |
804 | kerror("mkdir %s failed with error %d", dirname, ret); |
805 | return ERR_PTR(ret); |
806 | |
807 | lookup_error: |
808 | mutex_unlock(&dir->d_inode->i_mutex); |
809 | ret = PTR_ERR(subdir); |
810 | kerror("Lookup %s failed with error %d", dirname, ret); |
811 | return ERR_PTR(ret); |
812 | |
813 | nomem_d_alloc: |
814 | mutex_unlock(&dir->d_inode->i_mutex); |
815 | _leave(" = -ENOMEM"); |
816 | return ERR_PTR(-ENOMEM); |
817 | } |
818 | |
819 | /* |
820 | * find out if an object is in use or not |
821 | * - if finds object and it's not in use: |
822 | * - returns a pointer to the object and a reference on it |
823 | * - returns with the directory locked |
824 | */ |
825 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, |
826 | struct dentry *dir, |
827 | char *filename) |
828 | { |
829 | struct cachefiles_object *object; |
830 | struct rb_node *_n; |
831 | struct dentry *victim; |
832 | unsigned long start; |
833 | int ret; |
834 | |
835 | //_enter(",%*.*s/,%s", |
836 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); |
837 | |
838 | /* look up the victim */ |
839 | mutex_lock_nested(&dir->d_inode->i_mutex, 1); |
840 | |
841 | start = jiffies; |
842 | victim = lookup_one_len(filename, dir, strlen(filename)); |
843 | cachefiles_hist(cachefiles_lookup_histogram, start); |
844 | if (IS_ERR(victim)) |
845 | goto lookup_error; |
846 | |
847 | //_debug("victim -> %p %s", |
848 | // victim, victim->d_inode ? "positive" : "negative"); |
849 | |
850 | /* if the object is no longer there then we probably retired the object |
851 | * at the netfs's request whilst the cull was in progress |
852 | */ |
853 | if (!victim->d_inode) { |
854 | mutex_unlock(&dir->d_inode->i_mutex); |
855 | dput(victim); |
856 | _leave(" = -ENOENT [absent]"); |
857 | return ERR_PTR(-ENOENT); |
858 | } |
859 | |
860 | /* check to see if we're using this object */ |
861 | read_lock(&cache->active_lock); |
862 | |
863 | _n = cache->active_nodes.rb_node; |
864 | |
865 | while (_n) { |
866 | object = rb_entry(_n, struct cachefiles_object, active_node); |
867 | |
868 | if (object->dentry > victim) |
869 | _n = _n->rb_left; |
870 | else if (object->dentry < victim) |
871 | _n = _n->rb_right; |
872 | else |
873 | goto object_in_use; |
874 | } |
875 | |
876 | read_unlock(&cache->active_lock); |
877 | |
878 | //_leave(" = %p", victim); |
879 | return victim; |
880 | |
881 | object_in_use: |
882 | read_unlock(&cache->active_lock); |
883 | mutex_unlock(&dir->d_inode->i_mutex); |
884 | dput(victim); |
885 | //_leave(" = -EBUSY [in use]"); |
886 | return ERR_PTR(-EBUSY); |
887 | |
888 | lookup_error: |
889 | mutex_unlock(&dir->d_inode->i_mutex); |
890 | ret = PTR_ERR(victim); |
891 | if (ret == -ENOENT) { |
892 | /* file or dir now absent - probably retired by netfs */ |
893 | _leave(" = -ESTALE [absent]"); |
894 | return ERR_PTR(-ESTALE); |
895 | } |
896 | |
897 | if (ret == -EIO) { |
898 | cachefiles_io_error(cache, "Lookup failed"); |
899 | } else if (ret != -ENOMEM) { |
900 | kerror("Internal error: %d", ret); |
901 | ret = -EIO; |
902 | } |
903 | |
904 | _leave(" = %d", ret); |
905 | return ERR_PTR(ret); |
906 | } |
907 | |
908 | /* |
909 | * cull an object if it's not in use |
910 | * - called only by cache manager daemon |
911 | */ |
912 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, |
913 | char *filename) |
914 | { |
915 | struct dentry *victim; |
916 | int ret; |
917 | |
918 | _enter(",%*.*s/,%s", |
919 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); |
920 | |
921 | victim = cachefiles_check_active(cache, dir, filename); |
922 | if (IS_ERR(victim)) |
923 | return PTR_ERR(victim); |
924 | |
925 | _debug("victim -> %p %s", |
926 | victim, victim->d_inode ? "positive" : "negative"); |
927 | |
928 | /* okay... the victim is not being used so we can cull it |
929 | * - start by marking it as stale |
930 | */ |
931 | _debug("victim is cullable"); |
932 | |
933 | ret = cachefiles_remove_object_xattr(cache, victim); |
934 | if (ret < 0) |
935 | goto error_unlock; |
936 | |
937 | /* actually remove the victim (drops the dir mutex) */ |
938 | _debug("bury"); |
939 | |
940 | ret = cachefiles_bury_object(cache, dir, victim, false); |
941 | if (ret < 0) |
942 | goto error; |
943 | |
944 | dput(victim); |
945 | _leave(" = 0"); |
946 | return 0; |
947 | |
948 | error_unlock: |
949 | mutex_unlock(&dir->d_inode->i_mutex); |
950 | error: |
951 | dput(victim); |
952 | if (ret == -ENOENT) { |
953 | /* file or dir now absent - probably retired by netfs */ |
954 | _leave(" = -ESTALE [absent]"); |
955 | return -ESTALE; |
956 | } |
957 | |
958 | if (ret != -ENOMEM) { |
959 | kerror("Internal error: %d", ret); |
960 | ret = -EIO; |
961 | } |
962 | |
963 | _leave(" = %d", ret); |
964 | return ret; |
965 | } |
966 | |
967 | /* |
968 | * find out if an object is in use or not |
969 | * - called only by cache manager daemon |
970 | * - returns -EBUSY or 0 to indicate whether an object is in use or not |
971 | */ |
972 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, |
973 | char *filename) |
974 | { |
975 | struct dentry *victim; |
976 | |
977 | //_enter(",%*.*s/,%s", |
978 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); |
979 | |
980 | victim = cachefiles_check_active(cache, dir, filename); |
981 | if (IS_ERR(victim)) |
982 | return PTR_ERR(victim); |
983 | |
984 | mutex_unlock(&dir->d_inode->i_mutex); |
985 | dput(victim); |
986 | //_leave(" = 0"); |
987 | return 0; |
988 | } |
989 |
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Tags:
od-2011-09-04
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v2.6.34-rc5
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v3.9