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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); | |
8b8edefa | 40 | printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", |
d0e27b78 | 41 | prefix, fscache_object_states[object->fscache.state], |
8b8edefa | 42 | object->fscache.flags, work_busy(&object->fscache.work), |
d0e27b78 DH |
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 | ||
c61ea31d DH |
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 | ||
9ae326a6 DH |
148 | /* |
149 | * record the fact that an object is now active | |
150 | */ | |
fee096de DH |
151 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
152 | struct cachefiles_object *object) | |
9ae326a6 DH |
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 | ||
d0e27b78 DH |
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); | |
9ae326a6 | 166 | BUG(); |
d0e27b78 | 167 | } |
9ae326a6 DH |
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); | |
fee096de DH |
190 | _leave(" = 0"); |
191 | return 0; | |
9ae326a6 DH |
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"); | |
d0e27b78 | 200 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
201 | BUG(); |
202 | } | |
203 | atomic_inc(&xobject->usage); | |
204 | write_unlock(&cache->active_lock); | |
205 | ||
fee096de DH |
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 */ | |
8b8edefa | 215 | if (work_pending(&xobject->fscache.work)) { |
fee096de DH |
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 | |
8b8edefa | 223 | * is done, or the fscache_object is congested */ |
fee096de DH |
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; | |
8b8edefa TH |
231 | |
232 | requeue = fscache_object_sleep_till_congested(&timeout); | |
fee096de DH |
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)); | |
9ae326a6 DH |
254 | |
255 | cache->cache.ops->put_object(&xobject->fscache); | |
256 | goto try_again; | |
fee096de DH |
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; | |
9ae326a6 DH |
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, | |
c61ea31d DH |
274 | struct dentry *rep, |
275 | bool preemptive) | |
9ae326a6 DH |
276 | { |
277 | struct dentry *grave, *trap; | |
82140443 | 278 | struct path path, path_to_graveyard; |
9ae326a6 DH |
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 | ||
c61ea31d DH |
286 | _debug("remove %p from %p", rep, dir); |
287 | ||
9ae326a6 DH |
288 | /* non-directories can just be unlinked */ |
289 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
290 | _debug("unlink stale object"); | |
9ae326a6 | 291 | |
82140443 DH |
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 | } | |
c61ea31d | 303 | |
9ae326a6 DH |
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 */ | |
82140443 DH |
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); | |
9ae326a6 | 404 | |
82140443 DH |
405 | if (preemptive) |
406 | cachefiles_mark_object_buried(cache, rep); | |
407 | } | |
c61ea31d | 408 | |
9ae326a6 DH |
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 | ||
c61ea31d | 424 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); |
9ae326a6 DH |
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 | ||
6511de33 | 432 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae | 433 | |
c61ea31d DH |
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"); | |
8f9941ae DH |
438 | mutex_unlock(&dir->d_inode->i_mutex); |
439 | ret = 0; | |
c61ea31d DH |
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 | } | |
8f9941ae | 453 | } |
9ae326a6 DH |
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; | |
82140443 | 471 | struct path path; |
9ae326a6 DH |
472 | unsigned long start; |
473 | const char *name; | |
474 | int ret, nlen; | |
475 | ||
c61ea31d DH |
476 | _enter("OBJ%x{%p},OBJ%x,%s,", |
477 | parent->fscache.debug_id, parent->dentry, | |
478 | object->fscache.debug_id, key); | |
9ae326a6 DH |
479 | |
480 | cache = container_of(parent->fscache.cache, | |
481 | struct cachefiles_cache, cache); | |
82140443 | 482 | path.mnt = cache->mnt; |
9ae326a6 DH |
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 | ||
6511de33 | 509 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
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 | ||
82140443 DH |
536 | path.dentry = dir; |
537 | ret = security_path_mkdir(&path, next, 0); | |
538 | if (ret < 0) | |
539 | goto create_error; | |
9ae326a6 DH |
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 | ||
82140443 DH |
565 | path.dentry = dir; |
566 | ret = security_path_mknod(&path, next, S_IFREG, 0); | |
567 | if (ret < 0) | |
568 | goto create_error; | |
9ae326a6 | 569 | start = jiffies; |
312b63fb | 570 | ret = vfs_create(dir->d_inode, next, S_IFREG, true); |
9ae326a6 DH |
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 | ||
c61ea31d | 615 | ret = cachefiles_bury_object(cache, dir, next, true); |
9ae326a6 DH |
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 */ | |
fee096de | 628 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
629 | |
630 | mutex_unlock(&dir->d_inode->i_mutex); | |
631 | dput(dir); | |
632 | dir = NULL; | |
633 | ||
fee096de DH |
634 | if (ret == -ETIMEDOUT) |
635 | goto mark_active_timed_out; | |
636 | ||
9ae326a6 DH |
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) */ | |
68ac1234 AV |
649 | path.dentry = next; |
650 | touch_atime(&path); | |
9ae326a6 DH |
651 | } |
652 | ||
653 | /* open a file interface onto a data file */ | |
654 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
655 | if (S_ISREG(object->dentry->d_inode->i_mode)) { | |
656 | const struct address_space_operations *aops; | |
657 | ||
658 | ret = -EPERM; | |
659 | aops = object->dentry->d_inode->i_mapping->a_ops; | |
660 | if (!aops->bmap) | |
661 | goto check_error; | |
662 | ||
663 | object->backer = object->dentry; | |
664 | } else { | |
665 | BUG(); // TODO: open file in data-class subdir | |
666 | } | |
667 | } | |
668 | ||
669 | object->new = 0; | |
670 | fscache_obtained_object(&object->fscache); | |
671 | ||
672 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); | |
673 | return 0; | |
674 | ||
675 | create_error: | |
676 | _debug("create error %d", ret); | |
677 | if (ret == -EIO) | |
678 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
679 | goto error; | |
680 | ||
fee096de DH |
681 | mark_active_timed_out: |
682 | _debug("mark active timed out"); | |
683 | goto release_dentry; | |
684 | ||
9ae326a6 DH |
685 | check_error: |
686 | _debug("check error %d", ret); | |
687 | write_lock(&cache->active_lock); | |
688 | rb_erase(&object->active_node, &cache->active_nodes); | |
689 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
690 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
691 | write_unlock(&cache->active_lock); | |
fee096de | 692 | release_dentry: |
9ae326a6 DH |
693 | dput(object->dentry); |
694 | object->dentry = NULL; | |
695 | goto error_out; | |
696 | ||
697 | delete_error: | |
698 | _debug("delete error %d", ret); | |
699 | goto error_out2; | |
700 | ||
701 | lookup_error: | |
702 | _debug("lookup error %ld", PTR_ERR(next)); | |
703 | ret = PTR_ERR(next); | |
704 | if (ret == -EIO) | |
705 | cachefiles_io_error(cache, "Lookup failed"); | |
706 | next = NULL; | |
707 | error: | |
708 | mutex_unlock(&dir->d_inode->i_mutex); | |
709 | dput(next); | |
710 | error_out2: | |
711 | dput(dir); | |
712 | error_out: | |
9ae326a6 DH |
713 | _leave(" = error %d", -ret); |
714 | return ret; | |
715 | } | |
716 | ||
717 | /* | |
718 | * get a subdirectory | |
719 | */ | |
720 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
721 | struct dentry *dir, | |
722 | const char *dirname) | |
723 | { | |
724 | struct dentry *subdir; | |
725 | unsigned long start; | |
82140443 | 726 | struct path path; |
9ae326a6 DH |
727 | int ret; |
728 | ||
729 | _enter(",,%s", dirname); | |
730 | ||
731 | /* search the current directory for the element name */ | |
732 | mutex_lock(&dir->d_inode->i_mutex); | |
733 | ||
734 | start = jiffies; | |
735 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
736 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
737 | if (IS_ERR(subdir)) { | |
738 | if (PTR_ERR(subdir) == -ENOMEM) | |
739 | goto nomem_d_alloc; | |
740 | goto lookup_error; | |
741 | } | |
742 | ||
743 | _debug("subdir -> %p %s", | |
744 | subdir, subdir->d_inode ? "positive" : "negative"); | |
745 | ||
746 | /* we need to create the subdir if it doesn't exist yet */ | |
747 | if (!subdir->d_inode) { | |
748 | ret = cachefiles_has_space(cache, 1, 0); | |
749 | if (ret < 0) | |
750 | goto mkdir_error; | |
751 | ||
752 | _debug("attempt mkdir"); | |
753 | ||
82140443 DH |
754 | path.mnt = cache->mnt; |
755 | path.dentry = dir; | |
756 | ret = security_path_mkdir(&path, subdir, 0700); | |
757 | if (ret < 0) | |
758 | goto mkdir_error; | |
9ae326a6 DH |
759 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); |
760 | if (ret < 0) | |
761 | goto mkdir_error; | |
762 | ||
763 | ASSERT(subdir->d_inode); | |
764 | ||
765 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
766 | subdir, | |
767 | subdir->d_inode, | |
768 | subdir->d_inode->i_ino); | |
769 | } | |
770 | ||
771 | mutex_unlock(&dir->d_inode->i_mutex); | |
772 | ||
773 | /* we need to make sure the subdir is a directory */ | |
774 | ASSERT(subdir->d_inode); | |
775 | ||
776 | if (!S_ISDIR(subdir->d_inode->i_mode)) { | |
777 | kerror("%s is not a directory", dirname); | |
778 | ret = -EIO; | |
779 | goto check_error; | |
780 | } | |
781 | ||
782 | ret = -EPERM; | |
783 | if (!subdir->d_inode->i_op || | |
784 | !subdir->d_inode->i_op->setxattr || | |
785 | !subdir->d_inode->i_op->getxattr || | |
786 | !subdir->d_inode->i_op->lookup || | |
787 | !subdir->d_inode->i_op->mkdir || | |
788 | !subdir->d_inode->i_op->create || | |
789 | !subdir->d_inode->i_op->rename || | |
790 | !subdir->d_inode->i_op->rmdir || | |
791 | !subdir->d_inode->i_op->unlink) | |
792 | goto check_error; | |
793 | ||
794 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
795 | return subdir; | |
796 | ||
797 | check_error: | |
798 | dput(subdir); | |
799 | _leave(" = %d [check]", ret); | |
800 | return ERR_PTR(ret); | |
801 | ||
802 | mkdir_error: | |
803 | mutex_unlock(&dir->d_inode->i_mutex); | |
804 | dput(subdir); | |
805 | kerror("mkdir %s failed with error %d", dirname, ret); | |
806 | return ERR_PTR(ret); | |
807 | ||
808 | lookup_error: | |
809 | mutex_unlock(&dir->d_inode->i_mutex); | |
810 | ret = PTR_ERR(subdir); | |
811 | kerror("Lookup %s failed with error %d", dirname, ret); | |
812 | return ERR_PTR(ret); | |
813 | ||
814 | nomem_d_alloc: | |
815 | mutex_unlock(&dir->d_inode->i_mutex); | |
816 | _leave(" = -ENOMEM"); | |
817 | return ERR_PTR(-ENOMEM); | |
818 | } | |
819 | ||
820 | /* | |
821 | * find out if an object is in use or not | |
822 | * - if finds object and it's not in use: | |
823 | * - returns a pointer to the object and a reference on it | |
824 | * - returns with the directory locked | |
825 | */ | |
826 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
827 | struct dentry *dir, | |
828 | char *filename) | |
829 | { | |
830 | struct cachefiles_object *object; | |
831 | struct rb_node *_n; | |
832 | struct dentry *victim; | |
833 | unsigned long start; | |
834 | int ret; | |
835 | ||
836 | //_enter(",%*.*s/,%s", | |
837 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
838 | ||
839 | /* look up the victim */ | |
840 | mutex_lock_nested(&dir->d_inode->i_mutex, 1); | |
841 | ||
842 | start = jiffies; | |
843 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
844 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
845 | if (IS_ERR(victim)) | |
846 | goto lookup_error; | |
847 | ||
848 | //_debug("victim -> %p %s", | |
849 | // victim, victim->d_inode ? "positive" : "negative"); | |
850 | ||
851 | /* if the object is no longer there then we probably retired the object | |
852 | * at the netfs's request whilst the cull was in progress | |
853 | */ | |
854 | if (!victim->d_inode) { | |
855 | mutex_unlock(&dir->d_inode->i_mutex); | |
856 | dput(victim); | |
857 | _leave(" = -ENOENT [absent]"); | |
858 | return ERR_PTR(-ENOENT); | |
859 | } | |
860 | ||
861 | /* check to see if we're using this object */ | |
862 | read_lock(&cache->active_lock); | |
863 | ||
864 | _n = cache->active_nodes.rb_node; | |
865 | ||
866 | while (_n) { | |
867 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
868 | ||
869 | if (object->dentry > victim) | |
870 | _n = _n->rb_left; | |
871 | else if (object->dentry < victim) | |
872 | _n = _n->rb_right; | |
873 | else | |
874 | goto object_in_use; | |
875 | } | |
876 | ||
877 | read_unlock(&cache->active_lock); | |
878 | ||
879 | //_leave(" = %p", victim); | |
880 | return victim; | |
881 | ||
882 | object_in_use: | |
883 | read_unlock(&cache->active_lock); | |
884 | mutex_unlock(&dir->d_inode->i_mutex); | |
885 | dput(victim); | |
886 | //_leave(" = -EBUSY [in use]"); | |
887 | return ERR_PTR(-EBUSY); | |
888 | ||
889 | lookup_error: | |
890 | mutex_unlock(&dir->d_inode->i_mutex); | |
891 | ret = PTR_ERR(victim); | |
892 | if (ret == -ENOENT) { | |
893 | /* file or dir now absent - probably retired by netfs */ | |
894 | _leave(" = -ESTALE [absent]"); | |
895 | return ERR_PTR(-ESTALE); | |
896 | } | |
897 | ||
898 | if (ret == -EIO) { | |
899 | cachefiles_io_error(cache, "Lookup failed"); | |
900 | } else if (ret != -ENOMEM) { | |
901 | kerror("Internal error: %d", ret); | |
902 | ret = -EIO; | |
903 | } | |
904 | ||
905 | _leave(" = %d", ret); | |
906 | return ERR_PTR(ret); | |
907 | } | |
908 | ||
909 | /* | |
910 | * cull an object if it's not in use | |
911 | * - called only by cache manager daemon | |
912 | */ | |
913 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
914 | char *filename) | |
915 | { | |
916 | struct dentry *victim; | |
917 | int ret; | |
918 | ||
919 | _enter(",%*.*s/,%s", | |
920 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
921 | ||
922 | victim = cachefiles_check_active(cache, dir, filename); | |
923 | if (IS_ERR(victim)) | |
924 | return PTR_ERR(victim); | |
925 | ||
926 | _debug("victim -> %p %s", | |
927 | victim, victim->d_inode ? "positive" : "negative"); | |
928 | ||
929 | /* okay... the victim is not being used so we can cull it | |
930 | * - start by marking it as stale | |
931 | */ | |
932 | _debug("victim is cullable"); | |
933 | ||
934 | ret = cachefiles_remove_object_xattr(cache, victim); | |
935 | if (ret < 0) | |
936 | goto error_unlock; | |
937 | ||
938 | /* actually remove the victim (drops the dir mutex) */ | |
939 | _debug("bury"); | |
940 | ||
c61ea31d | 941 | ret = cachefiles_bury_object(cache, dir, victim, false); |
9ae326a6 DH |
942 | if (ret < 0) |
943 | goto error; | |
944 | ||
945 | dput(victim); | |
946 | _leave(" = 0"); | |
947 | return 0; | |
948 | ||
949 | error_unlock: | |
950 | mutex_unlock(&dir->d_inode->i_mutex); | |
951 | error: | |
952 | dput(victim); | |
953 | if (ret == -ENOENT) { | |
954 | /* file or dir now absent - probably retired by netfs */ | |
955 | _leave(" = -ESTALE [absent]"); | |
956 | return -ESTALE; | |
957 | } | |
958 | ||
959 | if (ret != -ENOMEM) { | |
960 | kerror("Internal error: %d", ret); | |
961 | ret = -EIO; | |
962 | } | |
963 | ||
964 | _leave(" = %d", ret); | |
965 | return ret; | |
966 | } | |
967 | ||
968 | /* | |
969 | * find out if an object is in use or not | |
970 | * - called only by cache manager daemon | |
971 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
972 | */ | |
973 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
974 | char *filename) | |
975 | { | |
976 | struct dentry *victim; | |
977 | ||
978 | //_enter(",%*.*s/,%s", | |
979 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
980 | ||
981 | victim = cachefiles_check_active(cache, dir, filename); | |
982 | if (IS_ERR(victim)) | |
983 | return PTR_ERR(victim); | |
984 | ||
985 | mutex_unlock(&dir->d_inode->i_mutex); | |
986 | dput(victim); | |
987 | //_leave(" = 0"); | |
988 | return 0; | |
989 | } |