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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> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
9ae326a6 DH |
23 | #include "internal.h" |
24 | ||
d0e27b78 DH |
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 swfl=%lx ev=%lx[%lx]\n", | |
41 | prefix, fscache_object_states[object->fscache.state], | |
42 | object->fscache.flags, object->fscache.work.flags, | |
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 | ||
9ae326a6 DH |
95 | /* |
96 | * record the fact that an object is now active | |
97 | */ | |
fee096de DH |
98 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
99 | struct cachefiles_object *object) | |
9ae326a6 DH |
100 | { |
101 | struct cachefiles_object *xobject; | |
102 | struct rb_node **_p, *_parent = NULL; | |
103 | struct dentry *dentry; | |
104 | ||
105 | _enter(",%p", object); | |
106 | ||
107 | try_again: | |
108 | write_lock(&cache->active_lock); | |
109 | ||
d0e27b78 DH |
110 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
111 | printk(KERN_ERR "CacheFiles: Error: Object already active\n"); | |
112 | cachefiles_printk_object(object, NULL); | |
9ae326a6 | 113 | BUG(); |
d0e27b78 | 114 | } |
9ae326a6 DH |
115 | |
116 | dentry = object->dentry; | |
117 | _p = &cache->active_nodes.rb_node; | |
118 | while (*_p) { | |
119 | _parent = *_p; | |
120 | xobject = rb_entry(_parent, | |
121 | struct cachefiles_object, active_node); | |
122 | ||
123 | ASSERT(xobject != object); | |
124 | ||
125 | if (xobject->dentry > dentry) | |
126 | _p = &(*_p)->rb_left; | |
127 | else if (xobject->dentry < dentry) | |
128 | _p = &(*_p)->rb_right; | |
129 | else | |
130 | goto wait_for_old_object; | |
131 | } | |
132 | ||
133 | rb_link_node(&object->active_node, _parent, _p); | |
134 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
135 | ||
136 | write_unlock(&cache->active_lock); | |
fee096de DH |
137 | _leave(" = 0"); |
138 | return 0; | |
9ae326a6 DH |
139 | |
140 | /* an old object from a previous incarnation is hogging the slot - we | |
141 | * need to wait for it to be destroyed */ | |
142 | wait_for_old_object: | |
143 | if (xobject->fscache.state < FSCACHE_OBJECT_DYING) { | |
144 | printk(KERN_ERR "\n"); | |
145 | printk(KERN_ERR "CacheFiles: Error:" | |
146 | " Unexpected object collision\n"); | |
d0e27b78 | 147 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
148 | BUG(); |
149 | } | |
150 | atomic_inc(&xobject->usage); | |
151 | write_unlock(&cache->active_lock); | |
152 | ||
fee096de DH |
153 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
154 | wait_queue_head_t *wq; | |
155 | ||
156 | signed long timeout = 60 * HZ; | |
157 | wait_queue_t wait; | |
158 | bool requeue; | |
159 | ||
160 | /* if the object we're waiting for is queued for processing, | |
161 | * then just put ourselves on the queue behind it */ | |
162 | if (slow_work_is_queued(&xobject->fscache.work)) { | |
163 | _debug("queue OBJ%x behind OBJ%x immediately", | |
164 | object->fscache.debug_id, | |
165 | xobject->fscache.debug_id); | |
166 | goto requeue; | |
167 | } | |
168 | ||
169 | /* otherwise we sleep until either the object we're waiting for | |
170 | * is done, or the slow-work facility wants the thread back to | |
171 | * do other work */ | |
172 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); | |
173 | init_wait(&wait); | |
174 | requeue = false; | |
175 | do { | |
176 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
177 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
178 | break; | |
179 | requeue = slow_work_sleep_till_thread_needed( | |
180 | &object->fscache.work, &timeout); | |
181 | } while (timeout > 0 && !requeue); | |
182 | finish_wait(wq, &wait); | |
183 | ||
184 | if (requeue && | |
185 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
186 | _debug("queue OBJ%x behind OBJ%x after wait", | |
187 | object->fscache.debug_id, | |
188 | xobject->fscache.debug_id); | |
189 | goto requeue; | |
190 | } | |
191 | ||
192 | if (timeout <= 0) { | |
193 | printk(KERN_ERR "\n"); | |
194 | printk(KERN_ERR "CacheFiles: Error: Overlong" | |
195 | " wait for old active object to go away\n"); | |
196 | cachefiles_printk_object(object, xobject); | |
197 | goto requeue; | |
198 | } | |
199 | } | |
200 | ||
201 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
9ae326a6 DH |
202 | |
203 | cache->cache.ops->put_object(&xobject->fscache); | |
204 | goto try_again; | |
fee096de DH |
205 | |
206 | requeue: | |
207 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
208 | cache->cache.ops->put_object(&xobject->fscache); | |
209 | _leave(" = -ETIMEDOUT"); | |
210 | return -ETIMEDOUT; | |
9ae326a6 DH |
211 | } |
212 | ||
213 | /* | |
214 | * delete an object representation from the cache | |
215 | * - file backed objects are unlinked | |
216 | * - directory backed objects are stuffed into the graveyard for userspace to | |
217 | * delete | |
218 | * - unlocks the directory mutex | |
219 | */ | |
220 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
221 | struct dentry *dir, | |
222 | struct dentry *rep) | |
223 | { | |
224 | struct dentry *grave, *trap; | |
225 | char nbuffer[8 + 8 + 1]; | |
226 | int ret; | |
227 | ||
228 | _enter(",'%*.*s','%*.*s'", | |
229 | dir->d_name.len, dir->d_name.len, dir->d_name.name, | |
230 | rep->d_name.len, rep->d_name.len, rep->d_name.name); | |
231 | ||
232 | /* non-directories can just be unlinked */ | |
233 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
234 | _debug("unlink stale object"); | |
235 | ret = vfs_unlink(dir->d_inode, rep); | |
236 | ||
237 | mutex_unlock(&dir->d_inode->i_mutex); | |
238 | ||
239 | if (ret == -EIO) | |
240 | cachefiles_io_error(cache, "Unlink failed"); | |
241 | ||
242 | _leave(" = %d", ret); | |
243 | return ret; | |
244 | } | |
245 | ||
246 | /* directories have to be moved to the graveyard */ | |
247 | _debug("move stale object to graveyard"); | |
248 | mutex_unlock(&dir->d_inode->i_mutex); | |
249 | ||
250 | try_again: | |
251 | /* first step is to make up a grave dentry in the graveyard */ | |
252 | sprintf(nbuffer, "%08x%08x", | |
253 | (uint32_t) get_seconds(), | |
254 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
255 | ||
256 | /* do the multiway lock magic */ | |
257 | trap = lock_rename(cache->graveyard, dir); | |
258 | ||
259 | /* do some checks before getting the grave dentry */ | |
260 | if (rep->d_parent != dir) { | |
261 | /* the entry was probably culled when we dropped the parent dir | |
262 | * lock */ | |
263 | unlock_rename(cache->graveyard, dir); | |
264 | _leave(" = 0 [culled?]"); | |
265 | return 0; | |
266 | } | |
267 | ||
268 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { | |
269 | unlock_rename(cache->graveyard, dir); | |
270 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
271 | return -EIO; | |
272 | } | |
273 | ||
274 | if (trap == rep) { | |
275 | unlock_rename(cache->graveyard, dir); | |
276 | cachefiles_io_error(cache, "May not make directory loop"); | |
277 | return -EIO; | |
278 | } | |
279 | ||
280 | if (d_mountpoint(rep)) { | |
281 | unlock_rename(cache->graveyard, dir); | |
282 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
283 | return -EIO; | |
284 | } | |
285 | ||
286 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
287 | if (IS_ERR(grave)) { | |
288 | unlock_rename(cache->graveyard, dir); | |
289 | ||
290 | if (PTR_ERR(grave) == -ENOMEM) { | |
291 | _leave(" = -ENOMEM"); | |
292 | return -ENOMEM; | |
293 | } | |
294 | ||
295 | cachefiles_io_error(cache, "Lookup error %ld", | |
296 | PTR_ERR(grave)); | |
297 | return -EIO; | |
298 | } | |
299 | ||
300 | if (grave->d_inode) { | |
301 | unlock_rename(cache->graveyard, dir); | |
302 | dput(grave); | |
303 | grave = NULL; | |
304 | cond_resched(); | |
305 | goto try_again; | |
306 | } | |
307 | ||
308 | if (d_mountpoint(grave)) { | |
309 | unlock_rename(cache->graveyard, dir); | |
310 | dput(grave); | |
311 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
312 | return -EIO; | |
313 | } | |
314 | ||
315 | /* target should not be an ancestor of source */ | |
316 | if (trap == grave) { | |
317 | unlock_rename(cache->graveyard, dir); | |
318 | dput(grave); | |
319 | cachefiles_io_error(cache, "May not make directory loop"); | |
320 | return -EIO; | |
321 | } | |
322 | ||
323 | /* attempt the rename */ | |
324 | ret = vfs_rename(dir->d_inode, rep, cache->graveyard->d_inode, grave); | |
325 | if (ret != 0 && ret != -ENOMEM) | |
326 | cachefiles_io_error(cache, "Rename failed with error %d", ret); | |
327 | ||
328 | unlock_rename(cache->graveyard, dir); | |
329 | dput(grave); | |
330 | _leave(" = 0"); | |
331 | return 0; | |
332 | } | |
333 | ||
334 | /* | |
335 | * delete an object representation from the cache | |
336 | */ | |
337 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
338 | struct cachefiles_object *object) | |
339 | { | |
340 | struct dentry *dir; | |
341 | int ret; | |
342 | ||
343 | _enter(",{%p}", object->dentry); | |
344 | ||
345 | ASSERT(object->dentry); | |
346 | ASSERT(object->dentry->d_inode); | |
347 | ASSERT(object->dentry->d_parent); | |
348 | ||
349 | dir = dget_parent(object->dentry); | |
350 | ||
6511de33 | 351 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae DH |
352 | |
353 | /* we need to check that our parent is _still_ our parent - it may have | |
354 | * been renamed */ | |
355 | if (dir == object->dentry->d_parent) { | |
356 | ret = cachefiles_bury_object(cache, dir, object->dentry); | |
357 | } else { | |
358 | /* it got moved, presumably by cachefilesd culling it, so it's | |
359 | * no longer in the key path and we can ignore it */ | |
360 | mutex_unlock(&dir->d_inode->i_mutex); | |
361 | ret = 0; | |
362 | } | |
9ae326a6 DH |
363 | |
364 | dput(dir); | |
365 | _leave(" = %d", ret); | |
366 | return ret; | |
367 | } | |
368 | ||
369 | /* | |
370 | * walk from the parent object to the child object through the backing | |
371 | * filesystem, creating directories as we go | |
372 | */ | |
373 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
374 | struct cachefiles_object *object, | |
375 | const char *key, | |
376 | struct cachefiles_xattr *auxdata) | |
377 | { | |
378 | struct cachefiles_cache *cache; | |
379 | struct dentry *dir, *next = NULL; | |
380 | unsigned long start; | |
381 | const char *name; | |
382 | int ret, nlen; | |
383 | ||
384 | _enter("{%p},,%s,", parent->dentry, key); | |
385 | ||
386 | cache = container_of(parent->fscache.cache, | |
387 | struct cachefiles_cache, cache); | |
388 | ||
389 | ASSERT(parent->dentry); | |
390 | ASSERT(parent->dentry->d_inode); | |
391 | ||
392 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { | |
393 | // TODO: convert file to dir | |
394 | _leave("looking up in none directory"); | |
395 | return -ENOBUFS; | |
396 | } | |
397 | ||
398 | dir = dget(parent->dentry); | |
399 | ||
400 | advance: | |
401 | /* attempt to transit the first directory component */ | |
402 | name = key; | |
403 | nlen = strlen(key); | |
404 | ||
405 | /* key ends in a double NUL */ | |
406 | key = key + nlen + 1; | |
407 | if (!*key) | |
408 | key = NULL; | |
409 | ||
410 | lookup_again: | |
411 | /* search the current directory for the element name */ | |
412 | _debug("lookup '%s'", name); | |
413 | ||
6511de33 | 414 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
415 | |
416 | start = jiffies; | |
417 | next = lookup_one_len(name, dir, nlen); | |
418 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
419 | if (IS_ERR(next)) | |
420 | goto lookup_error; | |
421 | ||
422 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); | |
423 | ||
424 | if (!key) | |
425 | object->new = !next->d_inode; | |
426 | ||
427 | /* if this element of the path doesn't exist, then the lookup phase | |
428 | * failed, and we can release any readers in the certain knowledge that | |
429 | * there's nothing for them to actually read */ | |
430 | if (!next->d_inode) | |
431 | fscache_object_lookup_negative(&object->fscache); | |
432 | ||
433 | /* we need to create the object if it's negative */ | |
434 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
435 | /* index objects and intervening tree levels must be subdirs */ | |
436 | if (!next->d_inode) { | |
437 | ret = cachefiles_has_space(cache, 1, 0); | |
438 | if (ret < 0) | |
439 | goto create_error; | |
440 | ||
441 | start = jiffies; | |
442 | ret = vfs_mkdir(dir->d_inode, next, 0); | |
443 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
444 | if (ret < 0) | |
445 | goto create_error; | |
446 | ||
447 | ASSERT(next->d_inode); | |
448 | ||
449 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
450 | next, next->d_inode, next->d_inode->i_ino); | |
451 | ||
452 | } else if (!S_ISDIR(next->d_inode->i_mode)) { | |
453 | kerror("inode %lu is not a directory", | |
454 | next->d_inode->i_ino); | |
455 | ret = -ENOBUFS; | |
456 | goto error; | |
457 | } | |
458 | ||
459 | } else { | |
460 | /* non-index objects start out life as files */ | |
461 | if (!next->d_inode) { | |
462 | ret = cachefiles_has_space(cache, 1, 0); | |
463 | if (ret < 0) | |
464 | goto create_error; | |
465 | ||
466 | start = jiffies; | |
467 | ret = vfs_create(dir->d_inode, next, S_IFREG, NULL); | |
468 | cachefiles_hist(cachefiles_create_histogram, start); | |
469 | if (ret < 0) | |
470 | goto create_error; | |
471 | ||
472 | ASSERT(next->d_inode); | |
473 | ||
474 | _debug("create -> %p{%p{ino=%lu}}", | |
475 | next, next->d_inode, next->d_inode->i_ino); | |
476 | ||
477 | } else if (!S_ISDIR(next->d_inode->i_mode) && | |
478 | !S_ISREG(next->d_inode->i_mode) | |
479 | ) { | |
480 | kerror("inode %lu is not a file or directory", | |
481 | next->d_inode->i_ino); | |
482 | ret = -ENOBUFS; | |
483 | goto error; | |
484 | } | |
485 | } | |
486 | ||
487 | /* process the next component */ | |
488 | if (key) { | |
489 | _debug("advance"); | |
490 | mutex_unlock(&dir->d_inode->i_mutex); | |
491 | dput(dir); | |
492 | dir = next; | |
493 | next = NULL; | |
494 | goto advance; | |
495 | } | |
496 | ||
497 | /* we've found the object we were looking for */ | |
498 | object->dentry = next; | |
499 | ||
500 | /* if we've found that the terminal object exists, then we need to | |
501 | * check its attributes and delete it if it's out of date */ | |
502 | if (!object->new) { | |
503 | _debug("validate '%*.*s'", | |
504 | next->d_name.len, next->d_name.len, next->d_name.name); | |
505 | ||
506 | ret = cachefiles_check_object_xattr(object, auxdata); | |
507 | if (ret == -ESTALE) { | |
508 | /* delete the object (the deleter drops the directory | |
509 | * mutex) */ | |
510 | object->dentry = NULL; | |
511 | ||
512 | ret = cachefiles_bury_object(cache, dir, next); | |
513 | dput(next); | |
514 | next = NULL; | |
515 | ||
516 | if (ret < 0) | |
517 | goto delete_error; | |
518 | ||
519 | _debug("redo lookup"); | |
520 | goto lookup_again; | |
521 | } | |
522 | } | |
523 | ||
524 | /* note that we're now using this object */ | |
fee096de | 525 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
526 | |
527 | mutex_unlock(&dir->d_inode->i_mutex); | |
528 | dput(dir); | |
529 | dir = NULL; | |
530 | ||
fee096de DH |
531 | if (ret == -ETIMEDOUT) |
532 | goto mark_active_timed_out; | |
533 | ||
9ae326a6 DH |
534 | _debug("=== OBTAINED_OBJECT ==="); |
535 | ||
536 | if (object->new) { | |
537 | /* attach data to a newly constructed terminal object */ | |
538 | ret = cachefiles_set_object_xattr(object, auxdata); | |
539 | if (ret < 0) | |
540 | goto check_error; | |
541 | } else { | |
542 | /* always update the atime on an object we've just looked up | |
543 | * (this is used to keep track of culling, and atimes are only | |
544 | * updated by read, write and readdir but not lookup or | |
545 | * open) */ | |
546 | touch_atime(cache->mnt, next); | |
547 | } | |
548 | ||
549 | /* open a file interface onto a data file */ | |
550 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
551 | if (S_ISREG(object->dentry->d_inode->i_mode)) { | |
552 | const struct address_space_operations *aops; | |
553 | ||
554 | ret = -EPERM; | |
555 | aops = object->dentry->d_inode->i_mapping->a_ops; | |
556 | if (!aops->bmap) | |
557 | goto check_error; | |
558 | ||
559 | object->backer = object->dentry; | |
560 | } else { | |
561 | BUG(); // TODO: open file in data-class subdir | |
562 | } | |
563 | } | |
564 | ||
565 | object->new = 0; | |
566 | fscache_obtained_object(&object->fscache); | |
567 | ||
568 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); | |
569 | return 0; | |
570 | ||
571 | create_error: | |
572 | _debug("create error %d", ret); | |
573 | if (ret == -EIO) | |
574 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
575 | goto error; | |
576 | ||
fee096de DH |
577 | mark_active_timed_out: |
578 | _debug("mark active timed out"); | |
579 | goto release_dentry; | |
580 | ||
9ae326a6 DH |
581 | check_error: |
582 | _debug("check error %d", ret); | |
583 | write_lock(&cache->active_lock); | |
584 | rb_erase(&object->active_node, &cache->active_nodes); | |
585 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
586 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
587 | write_unlock(&cache->active_lock); | |
fee096de | 588 | release_dentry: |
9ae326a6 DH |
589 | dput(object->dentry); |
590 | object->dentry = NULL; | |
591 | goto error_out; | |
592 | ||
593 | delete_error: | |
594 | _debug("delete error %d", ret); | |
595 | goto error_out2; | |
596 | ||
597 | lookup_error: | |
598 | _debug("lookup error %ld", PTR_ERR(next)); | |
599 | ret = PTR_ERR(next); | |
600 | if (ret == -EIO) | |
601 | cachefiles_io_error(cache, "Lookup failed"); | |
602 | next = NULL; | |
603 | error: | |
604 | mutex_unlock(&dir->d_inode->i_mutex); | |
605 | dput(next); | |
606 | error_out2: | |
607 | dput(dir); | |
608 | error_out: | |
9ae326a6 DH |
609 | _leave(" = error %d", -ret); |
610 | return ret; | |
611 | } | |
612 | ||
613 | /* | |
614 | * get a subdirectory | |
615 | */ | |
616 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
617 | struct dentry *dir, | |
618 | const char *dirname) | |
619 | { | |
620 | struct dentry *subdir; | |
621 | unsigned long start; | |
622 | int ret; | |
623 | ||
624 | _enter(",,%s", dirname); | |
625 | ||
626 | /* search the current directory for the element name */ | |
627 | mutex_lock(&dir->d_inode->i_mutex); | |
628 | ||
629 | start = jiffies; | |
630 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
631 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
632 | if (IS_ERR(subdir)) { | |
633 | if (PTR_ERR(subdir) == -ENOMEM) | |
634 | goto nomem_d_alloc; | |
635 | goto lookup_error; | |
636 | } | |
637 | ||
638 | _debug("subdir -> %p %s", | |
639 | subdir, subdir->d_inode ? "positive" : "negative"); | |
640 | ||
641 | /* we need to create the subdir if it doesn't exist yet */ | |
642 | if (!subdir->d_inode) { | |
643 | ret = cachefiles_has_space(cache, 1, 0); | |
644 | if (ret < 0) | |
645 | goto mkdir_error; | |
646 | ||
647 | _debug("attempt mkdir"); | |
648 | ||
649 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); | |
650 | if (ret < 0) | |
651 | goto mkdir_error; | |
652 | ||
653 | ASSERT(subdir->d_inode); | |
654 | ||
655 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
656 | subdir, | |
657 | subdir->d_inode, | |
658 | subdir->d_inode->i_ino); | |
659 | } | |
660 | ||
661 | mutex_unlock(&dir->d_inode->i_mutex); | |
662 | ||
663 | /* we need to make sure the subdir is a directory */ | |
664 | ASSERT(subdir->d_inode); | |
665 | ||
666 | if (!S_ISDIR(subdir->d_inode->i_mode)) { | |
667 | kerror("%s is not a directory", dirname); | |
668 | ret = -EIO; | |
669 | goto check_error; | |
670 | } | |
671 | ||
672 | ret = -EPERM; | |
673 | if (!subdir->d_inode->i_op || | |
674 | !subdir->d_inode->i_op->setxattr || | |
675 | !subdir->d_inode->i_op->getxattr || | |
676 | !subdir->d_inode->i_op->lookup || | |
677 | !subdir->d_inode->i_op->mkdir || | |
678 | !subdir->d_inode->i_op->create || | |
679 | !subdir->d_inode->i_op->rename || | |
680 | !subdir->d_inode->i_op->rmdir || | |
681 | !subdir->d_inode->i_op->unlink) | |
682 | goto check_error; | |
683 | ||
684 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
685 | return subdir; | |
686 | ||
687 | check_error: | |
688 | dput(subdir); | |
689 | _leave(" = %d [check]", ret); | |
690 | return ERR_PTR(ret); | |
691 | ||
692 | mkdir_error: | |
693 | mutex_unlock(&dir->d_inode->i_mutex); | |
694 | dput(subdir); | |
695 | kerror("mkdir %s failed with error %d", dirname, ret); | |
696 | return ERR_PTR(ret); | |
697 | ||
698 | lookup_error: | |
699 | mutex_unlock(&dir->d_inode->i_mutex); | |
700 | ret = PTR_ERR(subdir); | |
701 | kerror("Lookup %s failed with error %d", dirname, ret); | |
702 | return ERR_PTR(ret); | |
703 | ||
704 | nomem_d_alloc: | |
705 | mutex_unlock(&dir->d_inode->i_mutex); | |
706 | _leave(" = -ENOMEM"); | |
707 | return ERR_PTR(-ENOMEM); | |
708 | } | |
709 | ||
710 | /* | |
711 | * find out if an object is in use or not | |
712 | * - if finds object and it's not in use: | |
713 | * - returns a pointer to the object and a reference on it | |
714 | * - returns with the directory locked | |
715 | */ | |
716 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
717 | struct dentry *dir, | |
718 | char *filename) | |
719 | { | |
720 | struct cachefiles_object *object; | |
721 | struct rb_node *_n; | |
722 | struct dentry *victim; | |
723 | unsigned long start; | |
724 | int ret; | |
725 | ||
726 | //_enter(",%*.*s/,%s", | |
727 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
728 | ||
729 | /* look up the victim */ | |
730 | mutex_lock_nested(&dir->d_inode->i_mutex, 1); | |
731 | ||
732 | start = jiffies; | |
733 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
734 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
735 | if (IS_ERR(victim)) | |
736 | goto lookup_error; | |
737 | ||
738 | //_debug("victim -> %p %s", | |
739 | // victim, victim->d_inode ? "positive" : "negative"); | |
740 | ||
741 | /* if the object is no longer there then we probably retired the object | |
742 | * at the netfs's request whilst the cull was in progress | |
743 | */ | |
744 | if (!victim->d_inode) { | |
745 | mutex_unlock(&dir->d_inode->i_mutex); | |
746 | dput(victim); | |
747 | _leave(" = -ENOENT [absent]"); | |
748 | return ERR_PTR(-ENOENT); | |
749 | } | |
750 | ||
751 | /* check to see if we're using this object */ | |
752 | read_lock(&cache->active_lock); | |
753 | ||
754 | _n = cache->active_nodes.rb_node; | |
755 | ||
756 | while (_n) { | |
757 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
758 | ||
759 | if (object->dentry > victim) | |
760 | _n = _n->rb_left; | |
761 | else if (object->dentry < victim) | |
762 | _n = _n->rb_right; | |
763 | else | |
764 | goto object_in_use; | |
765 | } | |
766 | ||
767 | read_unlock(&cache->active_lock); | |
768 | ||
769 | //_leave(" = %p", victim); | |
770 | return victim; | |
771 | ||
772 | object_in_use: | |
773 | read_unlock(&cache->active_lock); | |
774 | mutex_unlock(&dir->d_inode->i_mutex); | |
775 | dput(victim); | |
776 | //_leave(" = -EBUSY [in use]"); | |
777 | return ERR_PTR(-EBUSY); | |
778 | ||
779 | lookup_error: | |
780 | mutex_unlock(&dir->d_inode->i_mutex); | |
781 | ret = PTR_ERR(victim); | |
782 | if (ret == -ENOENT) { | |
783 | /* file or dir now absent - probably retired by netfs */ | |
784 | _leave(" = -ESTALE [absent]"); | |
785 | return ERR_PTR(-ESTALE); | |
786 | } | |
787 | ||
788 | if (ret == -EIO) { | |
789 | cachefiles_io_error(cache, "Lookup failed"); | |
790 | } else if (ret != -ENOMEM) { | |
791 | kerror("Internal error: %d", ret); | |
792 | ret = -EIO; | |
793 | } | |
794 | ||
795 | _leave(" = %d", ret); | |
796 | return ERR_PTR(ret); | |
797 | } | |
798 | ||
799 | /* | |
800 | * cull an object if it's not in use | |
801 | * - called only by cache manager daemon | |
802 | */ | |
803 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
804 | char *filename) | |
805 | { | |
806 | struct dentry *victim; | |
807 | int ret; | |
808 | ||
809 | _enter(",%*.*s/,%s", | |
810 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
811 | ||
812 | victim = cachefiles_check_active(cache, dir, filename); | |
813 | if (IS_ERR(victim)) | |
814 | return PTR_ERR(victim); | |
815 | ||
816 | _debug("victim -> %p %s", | |
817 | victim, victim->d_inode ? "positive" : "negative"); | |
818 | ||
819 | /* okay... the victim is not being used so we can cull it | |
820 | * - start by marking it as stale | |
821 | */ | |
822 | _debug("victim is cullable"); | |
823 | ||
824 | ret = cachefiles_remove_object_xattr(cache, victim); | |
825 | if (ret < 0) | |
826 | goto error_unlock; | |
827 | ||
828 | /* actually remove the victim (drops the dir mutex) */ | |
829 | _debug("bury"); | |
830 | ||
831 | ret = cachefiles_bury_object(cache, dir, victim); | |
832 | if (ret < 0) | |
833 | goto error; | |
834 | ||
835 | dput(victim); | |
836 | _leave(" = 0"); | |
837 | return 0; | |
838 | ||
839 | error_unlock: | |
840 | mutex_unlock(&dir->d_inode->i_mutex); | |
841 | error: | |
842 | dput(victim); | |
843 | if (ret == -ENOENT) { | |
844 | /* file or dir now absent - probably retired by netfs */ | |
845 | _leave(" = -ESTALE [absent]"); | |
846 | return -ESTALE; | |
847 | } | |
848 | ||
849 | if (ret != -ENOMEM) { | |
850 | kerror("Internal error: %d", ret); | |
851 | ret = -EIO; | |
852 | } | |
853 | ||
854 | _leave(" = %d", ret); | |
855 | return ret; | |
856 | } | |
857 | ||
858 | /* | |
859 | * find out if an object is in use or not | |
860 | * - called only by cache manager daemon | |
861 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
862 | */ | |
863 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
864 | char *filename) | |
865 | { | |
866 | struct dentry *victim; | |
867 | ||
868 | //_enter(",%*.*s/,%s", | |
869 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
870 | ||
871 | victim = cachefiles_check_active(cache, dir, filename); | |
872 | if (IS_ERR(victim)) | |
873 | return PTR_ERR(victim); | |
874 | ||
875 | mutex_unlock(&dir->d_inode->i_mutex); | |
876 | dput(victim); | |
877 | //_leave(" = 0"); | |
878 | return 0; | |
879 | } |