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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", |
caaef690 | 41 | prefix, object->fscache.state->name, |
8b8edefa | 42 | object->fscache.flags, work_busy(&object->fscache.work), |
c2d35bfe | 43 | object->fscache.events, object->fscache.event_mask); |
d0e27b78 DH |
44 | printk(KERN_ERR "%sops=%u inp=%u exc=%u\n", |
45 | prefix, object->fscache.n_ops, object->fscache.n_in_progress, | |
46 | object->fscache.n_exclusive); | |
47 | printk(KERN_ERR "%sparent=%p\n", | |
48 | prefix, object->fscache.parent); | |
49 | ||
50 | spin_lock(&object->fscache.lock); | |
51 | cookie = object->fscache.cookie; | |
52 | if (cookie) { | |
53 | printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n", | |
54 | prefix, | |
55 | object->fscache.cookie, | |
56 | object->fscache.cookie->parent, | |
57 | object->fscache.cookie->netfs_data, | |
58 | object->fscache.cookie->flags); | |
509bf24d | 59 | if (keybuf && cookie->def) |
d0e27b78 DH |
60 | keylen = cookie->def->get_key(cookie->netfs_data, keybuf, |
61 | CACHEFILES_KEYBUF_SIZE); | |
62 | else | |
63 | keylen = 0; | |
64 | } else { | |
65 | printk(KERN_ERR "%scookie=NULL\n", prefix); | |
66 | keylen = 0; | |
67 | } | |
68 | spin_unlock(&object->fscache.lock); | |
69 | ||
70 | if (keylen) { | |
71 | printk(KERN_ERR "%skey=[%u] '", prefix, keylen); | |
72 | for (loop = 0; loop < keylen; loop++) | |
73 | printk("%02x", keybuf[loop]); | |
74 | printk("'\n"); | |
75 | } | |
76 | } | |
77 | ||
78 | /* | |
79 | * dump debugging info about a pair of objects | |
80 | */ | |
81 | static noinline void cachefiles_printk_object(struct cachefiles_object *object, | |
82 | struct cachefiles_object *xobject) | |
83 | { | |
84 | u8 *keybuf; | |
85 | ||
86 | keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); | |
87 | if (object) | |
88 | __cachefiles_printk_object(object, "", keybuf); | |
89 | if (xobject) | |
90 | __cachefiles_printk_object(xobject, "x", keybuf); | |
91 | kfree(keybuf); | |
92 | } | |
93 | ||
c61ea31d DH |
94 | /* |
95 | * mark the owner of a dentry, if there is one, to indicate that that dentry | |
96 | * has been preemptively deleted | |
97 | * - the caller must hold the i_mutex on the dentry's parent as required to | |
98 | * call vfs_unlink(), vfs_rmdir() or vfs_rename() | |
99 | */ | |
100 | static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, | |
101 | struct dentry *dentry) | |
102 | { | |
103 | struct cachefiles_object *object; | |
104 | struct rb_node *p; | |
105 | ||
106 | _enter(",'%*.*s'", | |
107 | dentry->d_name.len, dentry->d_name.len, dentry->d_name.name); | |
108 | ||
109 | write_lock(&cache->active_lock); | |
110 | ||
111 | p = cache->active_nodes.rb_node; | |
112 | while (p) { | |
113 | object = rb_entry(p, struct cachefiles_object, active_node); | |
114 | if (object->dentry > dentry) | |
115 | p = p->rb_left; | |
116 | else if (object->dentry < dentry) | |
117 | p = p->rb_right; | |
118 | else | |
119 | goto found_dentry; | |
120 | } | |
121 | ||
122 | write_unlock(&cache->active_lock); | |
123 | _leave(" [no owner]"); | |
124 | return; | |
125 | ||
126 | /* found the dentry for */ | |
127 | found_dentry: | |
128 | kdebug("preemptive burial: OBJ%x [%s] %p", | |
129 | object->fscache.debug_id, | |
caaef690 | 130 | object->fscache.state->name, |
c61ea31d DH |
131 | dentry); |
132 | ||
493f7bc1 | 133 | if (fscache_object_is_live(&object->fscache)) { |
c61ea31d DH |
134 | printk(KERN_ERR "\n"); |
135 | printk(KERN_ERR "CacheFiles: Error:" | |
136 | " Can't preemptively bury live object\n"); | |
137 | cachefiles_printk_object(object, NULL); | |
138 | } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { | |
139 | printk(KERN_ERR "CacheFiles: Error:" | |
140 | " Object already preemptively buried\n"); | |
141 | } | |
142 | ||
143 | write_unlock(&cache->active_lock); | |
144 | _leave(" [owner marked]"); | |
145 | } | |
146 | ||
9ae326a6 DH |
147 | /* |
148 | * record the fact that an object is now active | |
149 | */ | |
fee096de DH |
150 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
151 | struct cachefiles_object *object) | |
9ae326a6 DH |
152 | { |
153 | struct cachefiles_object *xobject; | |
154 | struct rb_node **_p, *_parent = NULL; | |
155 | struct dentry *dentry; | |
156 | ||
157 | _enter(",%p", object); | |
158 | ||
159 | try_again: | |
160 | write_lock(&cache->active_lock); | |
161 | ||
d0e27b78 DH |
162 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
163 | printk(KERN_ERR "CacheFiles: Error: Object already active\n"); | |
164 | cachefiles_printk_object(object, NULL); | |
9ae326a6 | 165 | BUG(); |
d0e27b78 | 166 | } |
9ae326a6 DH |
167 | |
168 | dentry = object->dentry; | |
169 | _p = &cache->active_nodes.rb_node; | |
170 | while (*_p) { | |
171 | _parent = *_p; | |
172 | xobject = rb_entry(_parent, | |
173 | struct cachefiles_object, active_node); | |
174 | ||
175 | ASSERT(xobject != object); | |
176 | ||
177 | if (xobject->dentry > dentry) | |
178 | _p = &(*_p)->rb_left; | |
179 | else if (xobject->dentry < dentry) | |
180 | _p = &(*_p)->rb_right; | |
181 | else | |
182 | goto wait_for_old_object; | |
183 | } | |
184 | ||
185 | rb_link_node(&object->active_node, _parent, _p); | |
186 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
187 | ||
188 | write_unlock(&cache->active_lock); | |
fee096de DH |
189 | _leave(" = 0"); |
190 | return 0; | |
9ae326a6 DH |
191 | |
192 | /* an old object from a previous incarnation is hogging the slot - we | |
193 | * need to wait for it to be destroyed */ | |
194 | wait_for_old_object: | |
493f7bc1 | 195 | if (fscache_object_is_live(&object->fscache)) { |
9ae326a6 DH |
196 | printk(KERN_ERR "\n"); |
197 | printk(KERN_ERR "CacheFiles: Error:" | |
198 | " Unexpected object collision\n"); | |
d0e27b78 | 199 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
200 | BUG(); |
201 | } | |
202 | atomic_inc(&xobject->usage); | |
203 | write_unlock(&cache->active_lock); | |
204 | ||
fee096de DH |
205 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
206 | wait_queue_head_t *wq; | |
207 | ||
208 | signed long timeout = 60 * HZ; | |
209 | wait_queue_t wait; | |
210 | bool requeue; | |
211 | ||
212 | /* if the object we're waiting for is queued for processing, | |
213 | * then just put ourselves on the queue behind it */ | |
8b8edefa | 214 | if (work_pending(&xobject->fscache.work)) { |
fee096de DH |
215 | _debug("queue OBJ%x behind OBJ%x immediately", |
216 | object->fscache.debug_id, | |
217 | xobject->fscache.debug_id); | |
218 | goto requeue; | |
219 | } | |
220 | ||
221 | /* otherwise we sleep until either the object we're waiting for | |
8b8edefa | 222 | * is done, or the fscache_object is congested */ |
fee096de DH |
223 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); |
224 | init_wait(&wait); | |
225 | requeue = false; | |
226 | do { | |
227 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
228 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
229 | break; | |
8b8edefa TH |
230 | |
231 | requeue = fscache_object_sleep_till_congested(&timeout); | |
fee096de DH |
232 | } while (timeout > 0 && !requeue); |
233 | finish_wait(wq, &wait); | |
234 | ||
235 | if (requeue && | |
236 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
237 | _debug("queue OBJ%x behind OBJ%x after wait", | |
238 | object->fscache.debug_id, | |
239 | xobject->fscache.debug_id); | |
240 | goto requeue; | |
241 | } | |
242 | ||
243 | if (timeout <= 0) { | |
244 | printk(KERN_ERR "\n"); | |
245 | printk(KERN_ERR "CacheFiles: Error: Overlong" | |
246 | " wait for old active object to go away\n"); | |
247 | cachefiles_printk_object(object, xobject); | |
248 | goto requeue; | |
249 | } | |
250 | } | |
251 | ||
252 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
9ae326a6 DH |
253 | |
254 | cache->cache.ops->put_object(&xobject->fscache); | |
255 | goto try_again; | |
fee096de DH |
256 | |
257 | requeue: | |
258 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
259 | cache->cache.ops->put_object(&xobject->fscache); | |
260 | _leave(" = -ETIMEDOUT"); | |
261 | return -ETIMEDOUT; | |
9ae326a6 DH |
262 | } |
263 | ||
264 | /* | |
265 | * delete an object representation from the cache | |
266 | * - file backed objects are unlinked | |
267 | * - directory backed objects are stuffed into the graveyard for userspace to | |
268 | * delete | |
269 | * - unlocks the directory mutex | |
270 | */ | |
271 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
272 | struct dentry *dir, | |
c61ea31d DH |
273 | struct dentry *rep, |
274 | bool preemptive) | |
9ae326a6 DH |
275 | { |
276 | struct dentry *grave, *trap; | |
82140443 | 277 | struct path path, path_to_graveyard; |
9ae326a6 DH |
278 | char nbuffer[8 + 8 + 1]; |
279 | int ret; | |
280 | ||
281 | _enter(",'%*.*s','%*.*s'", | |
282 | dir->d_name.len, dir->d_name.len, dir->d_name.name, | |
283 | rep->d_name.len, rep->d_name.len, rep->d_name.name); | |
284 | ||
c61ea31d DH |
285 | _debug("remove %p from %p", rep, dir); |
286 | ||
9ae326a6 DH |
287 | /* non-directories can just be unlinked */ |
288 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
289 | _debug("unlink stale object"); | |
9ae326a6 | 290 | |
82140443 DH |
291 | path.mnt = cache->mnt; |
292 | path.dentry = dir; | |
293 | ret = security_path_unlink(&path, rep); | |
294 | if (ret < 0) { | |
295 | cachefiles_io_error(cache, "Unlink security error"); | |
296 | } else { | |
b21996e3 | 297 | ret = vfs_unlink(dir->d_inode, rep, NULL); |
82140443 DH |
298 | |
299 | if (preemptive) | |
300 | cachefiles_mark_object_buried(cache, rep); | |
301 | } | |
c61ea31d | 302 | |
9ae326a6 DH |
303 | mutex_unlock(&dir->d_inode->i_mutex); |
304 | ||
305 | if (ret == -EIO) | |
306 | cachefiles_io_error(cache, "Unlink failed"); | |
307 | ||
308 | _leave(" = %d", ret); | |
309 | return ret; | |
310 | } | |
311 | ||
312 | /* directories have to be moved to the graveyard */ | |
313 | _debug("move stale object to graveyard"); | |
314 | mutex_unlock(&dir->d_inode->i_mutex); | |
315 | ||
316 | try_again: | |
317 | /* first step is to make up a grave dentry in the graveyard */ | |
318 | sprintf(nbuffer, "%08x%08x", | |
319 | (uint32_t) get_seconds(), | |
320 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
321 | ||
322 | /* do the multiway lock magic */ | |
323 | trap = lock_rename(cache->graveyard, dir); | |
324 | ||
325 | /* do some checks before getting the grave dentry */ | |
326 | if (rep->d_parent != dir) { | |
327 | /* the entry was probably culled when we dropped the parent dir | |
328 | * lock */ | |
329 | unlock_rename(cache->graveyard, dir); | |
330 | _leave(" = 0 [culled?]"); | |
331 | return 0; | |
332 | } | |
333 | ||
334 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { | |
335 | unlock_rename(cache->graveyard, dir); | |
336 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
337 | return -EIO; | |
338 | } | |
339 | ||
340 | if (trap == rep) { | |
341 | unlock_rename(cache->graveyard, dir); | |
342 | cachefiles_io_error(cache, "May not make directory loop"); | |
343 | return -EIO; | |
344 | } | |
345 | ||
346 | if (d_mountpoint(rep)) { | |
347 | unlock_rename(cache->graveyard, dir); | |
348 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
349 | return -EIO; | |
350 | } | |
351 | ||
352 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
353 | if (IS_ERR(grave)) { | |
354 | unlock_rename(cache->graveyard, dir); | |
355 | ||
356 | if (PTR_ERR(grave) == -ENOMEM) { | |
357 | _leave(" = -ENOMEM"); | |
358 | return -ENOMEM; | |
359 | } | |
360 | ||
361 | cachefiles_io_error(cache, "Lookup error %ld", | |
362 | PTR_ERR(grave)); | |
363 | return -EIO; | |
364 | } | |
365 | ||
366 | if (grave->d_inode) { | |
367 | unlock_rename(cache->graveyard, dir); | |
368 | dput(grave); | |
369 | grave = NULL; | |
370 | cond_resched(); | |
371 | goto try_again; | |
372 | } | |
373 | ||
374 | if (d_mountpoint(grave)) { | |
375 | unlock_rename(cache->graveyard, dir); | |
376 | dput(grave); | |
377 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
378 | return -EIO; | |
379 | } | |
380 | ||
381 | /* target should not be an ancestor of source */ | |
382 | if (trap == grave) { | |
383 | unlock_rename(cache->graveyard, dir); | |
384 | dput(grave); | |
385 | cachefiles_io_error(cache, "May not make directory loop"); | |
386 | return -EIO; | |
387 | } | |
388 | ||
389 | /* attempt the rename */ | |
82140443 DH |
390 | path.mnt = cache->mnt; |
391 | path.dentry = dir; | |
392 | path_to_graveyard.mnt = cache->mnt; | |
393 | path_to_graveyard.dentry = cache->graveyard; | |
0b3974eb | 394 | ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); |
82140443 DH |
395 | if (ret < 0) { |
396 | cachefiles_io_error(cache, "Rename security error %d", ret); | |
397 | } else { | |
398 | ret = vfs_rename(dir->d_inode, rep, | |
520c8b16 | 399 | cache->graveyard->d_inode, grave, NULL, 0); |
82140443 DH |
400 | if (ret != 0 && ret != -ENOMEM) |
401 | cachefiles_io_error(cache, | |
402 | "Rename failed with error %d", ret); | |
9ae326a6 | 403 | |
82140443 DH |
404 | if (preemptive) |
405 | cachefiles_mark_object_buried(cache, rep); | |
406 | } | |
c61ea31d | 407 | |
9ae326a6 DH |
408 | unlock_rename(cache->graveyard, dir); |
409 | dput(grave); | |
410 | _leave(" = 0"); | |
411 | return 0; | |
412 | } | |
413 | ||
414 | /* | |
415 | * delete an object representation from the cache | |
416 | */ | |
417 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
418 | struct cachefiles_object *object) | |
419 | { | |
420 | struct dentry *dir; | |
421 | int ret; | |
422 | ||
c61ea31d | 423 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); |
9ae326a6 DH |
424 | |
425 | ASSERT(object->dentry); | |
426 | ASSERT(object->dentry->d_inode); | |
427 | ASSERT(object->dentry->d_parent); | |
428 | ||
429 | dir = dget_parent(object->dentry); | |
430 | ||
6511de33 | 431 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae | 432 | |
c61ea31d DH |
433 | if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { |
434 | /* object allocation for the same key preemptively deleted this | |
435 | * object's file so that it could create its own file */ | |
436 | _debug("object preemptively buried"); | |
8f9941ae DH |
437 | mutex_unlock(&dir->d_inode->i_mutex); |
438 | ret = 0; | |
c61ea31d DH |
439 | } else { |
440 | /* we need to check that our parent is _still_ our parent - it | |
441 | * may have been renamed */ | |
442 | if (dir == object->dentry->d_parent) { | |
443 | ret = cachefiles_bury_object(cache, dir, | |
444 | object->dentry, false); | |
445 | } else { | |
446 | /* it got moved, presumably by cachefilesd culling it, | |
447 | * so it's no longer in the key path and we can ignore | |
448 | * it */ | |
449 | mutex_unlock(&dir->d_inode->i_mutex); | |
450 | ret = 0; | |
451 | } | |
8f9941ae | 452 | } |
9ae326a6 DH |
453 | |
454 | dput(dir); | |
455 | _leave(" = %d", ret); | |
456 | return ret; | |
457 | } | |
458 | ||
459 | /* | |
460 | * walk from the parent object to the child object through the backing | |
461 | * filesystem, creating directories as we go | |
462 | */ | |
463 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
464 | struct cachefiles_object *object, | |
465 | const char *key, | |
466 | struct cachefiles_xattr *auxdata) | |
467 | { | |
468 | struct cachefiles_cache *cache; | |
469 | struct dentry *dir, *next = NULL; | |
82140443 | 470 | struct path path; |
9ae326a6 DH |
471 | unsigned long start; |
472 | const char *name; | |
473 | int ret, nlen; | |
474 | ||
c61ea31d DH |
475 | _enter("OBJ%x{%p},OBJ%x,%s,", |
476 | parent->fscache.debug_id, parent->dentry, | |
477 | object->fscache.debug_id, key); | |
9ae326a6 DH |
478 | |
479 | cache = container_of(parent->fscache.cache, | |
480 | struct cachefiles_cache, cache); | |
82140443 | 481 | path.mnt = cache->mnt; |
9ae326a6 DH |
482 | |
483 | ASSERT(parent->dentry); | |
484 | ASSERT(parent->dentry->d_inode); | |
485 | ||
486 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { | |
487 | // TODO: convert file to dir | |
488 | _leave("looking up in none directory"); | |
489 | return -ENOBUFS; | |
490 | } | |
491 | ||
492 | dir = dget(parent->dentry); | |
493 | ||
494 | advance: | |
495 | /* attempt to transit the first directory component */ | |
496 | name = key; | |
497 | nlen = strlen(key); | |
498 | ||
499 | /* key ends in a double NUL */ | |
500 | key = key + nlen + 1; | |
501 | if (!*key) | |
502 | key = NULL; | |
503 | ||
504 | lookup_again: | |
505 | /* search the current directory for the element name */ | |
506 | _debug("lookup '%s'", name); | |
507 | ||
6511de33 | 508 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
509 | |
510 | start = jiffies; | |
511 | next = lookup_one_len(name, dir, nlen); | |
512 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
513 | if (IS_ERR(next)) | |
514 | goto lookup_error; | |
515 | ||
516 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); | |
517 | ||
518 | if (!key) | |
519 | object->new = !next->d_inode; | |
520 | ||
521 | /* if this element of the path doesn't exist, then the lookup phase | |
522 | * failed, and we can release any readers in the certain knowledge that | |
523 | * there's nothing for them to actually read */ | |
524 | if (!next->d_inode) | |
525 | fscache_object_lookup_negative(&object->fscache); | |
526 | ||
527 | /* we need to create the object if it's negative */ | |
528 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
529 | /* index objects and intervening tree levels must be subdirs */ | |
530 | if (!next->d_inode) { | |
531 | ret = cachefiles_has_space(cache, 1, 0); | |
532 | if (ret < 0) | |
533 | goto create_error; | |
534 | ||
82140443 DH |
535 | path.dentry = dir; |
536 | ret = security_path_mkdir(&path, next, 0); | |
537 | if (ret < 0) | |
538 | goto create_error; | |
9ae326a6 DH |
539 | start = jiffies; |
540 | ret = vfs_mkdir(dir->d_inode, next, 0); | |
541 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
542 | if (ret < 0) | |
543 | goto create_error; | |
544 | ||
545 | ASSERT(next->d_inode); | |
546 | ||
547 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
548 | next, next->d_inode, next->d_inode->i_ino); | |
549 | ||
550 | } else if (!S_ISDIR(next->d_inode->i_mode)) { | |
551 | kerror("inode %lu is not a directory", | |
552 | next->d_inode->i_ino); | |
553 | ret = -ENOBUFS; | |
554 | goto error; | |
555 | } | |
556 | ||
557 | } else { | |
558 | /* non-index objects start out life as files */ | |
559 | if (!next->d_inode) { | |
560 | ret = cachefiles_has_space(cache, 1, 0); | |
561 | if (ret < 0) | |
562 | goto create_error; | |
563 | ||
82140443 DH |
564 | path.dentry = dir; |
565 | ret = security_path_mknod(&path, next, S_IFREG, 0); | |
566 | if (ret < 0) | |
567 | goto create_error; | |
9ae326a6 | 568 | start = jiffies; |
312b63fb | 569 | ret = vfs_create(dir->d_inode, next, S_IFREG, true); |
9ae326a6 DH |
570 | cachefiles_hist(cachefiles_create_histogram, start); |
571 | if (ret < 0) | |
572 | goto create_error; | |
573 | ||
574 | ASSERT(next->d_inode); | |
575 | ||
576 | _debug("create -> %p{%p{ino=%lu}}", | |
577 | next, next->d_inode, next->d_inode->i_ino); | |
578 | ||
579 | } else if (!S_ISDIR(next->d_inode->i_mode) && | |
580 | !S_ISREG(next->d_inode->i_mode) | |
581 | ) { | |
582 | kerror("inode %lu is not a file or directory", | |
583 | next->d_inode->i_ino); | |
584 | ret = -ENOBUFS; | |
585 | goto error; | |
586 | } | |
587 | } | |
588 | ||
589 | /* process the next component */ | |
590 | if (key) { | |
591 | _debug("advance"); | |
592 | mutex_unlock(&dir->d_inode->i_mutex); | |
593 | dput(dir); | |
594 | dir = next; | |
595 | next = NULL; | |
596 | goto advance; | |
597 | } | |
598 | ||
599 | /* we've found the object we were looking for */ | |
600 | object->dentry = next; | |
601 | ||
602 | /* if we've found that the terminal object exists, then we need to | |
603 | * check its attributes and delete it if it's out of date */ | |
604 | if (!object->new) { | |
605 | _debug("validate '%*.*s'", | |
606 | next->d_name.len, next->d_name.len, next->d_name.name); | |
607 | ||
608 | ret = cachefiles_check_object_xattr(object, auxdata); | |
609 | if (ret == -ESTALE) { | |
610 | /* delete the object (the deleter drops the directory | |
611 | * mutex) */ | |
612 | object->dentry = NULL; | |
613 | ||
c61ea31d | 614 | ret = cachefiles_bury_object(cache, dir, next, true); |
9ae326a6 DH |
615 | dput(next); |
616 | next = NULL; | |
617 | ||
618 | if (ret < 0) | |
619 | goto delete_error; | |
620 | ||
621 | _debug("redo lookup"); | |
622 | goto lookup_again; | |
623 | } | |
624 | } | |
625 | ||
626 | /* note that we're now using this object */ | |
fee096de | 627 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
628 | |
629 | mutex_unlock(&dir->d_inode->i_mutex); | |
630 | dput(dir); | |
631 | dir = NULL; | |
632 | ||
fee096de DH |
633 | if (ret == -ETIMEDOUT) |
634 | goto mark_active_timed_out; | |
635 | ||
9ae326a6 DH |
636 | _debug("=== OBTAINED_OBJECT ==="); |
637 | ||
638 | if (object->new) { | |
639 | /* attach data to a newly constructed terminal object */ | |
640 | ret = cachefiles_set_object_xattr(object, auxdata); | |
641 | if (ret < 0) | |
642 | goto check_error; | |
643 | } else { | |
644 | /* always update the atime on an object we've just looked up | |
645 | * (this is used to keep track of culling, and atimes are only | |
646 | * updated by read, write and readdir but not lookup or | |
647 | * open) */ | |
68ac1234 AV |
648 | path.dentry = next; |
649 | touch_atime(&path); | |
9ae326a6 DH |
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 | ||
fee096de DH |
680 | mark_active_timed_out: |
681 | _debug("mark active timed out"); | |
682 | goto release_dentry; | |
683 | ||
9ae326a6 DH |
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); | |
fee096de | 691 | release_dentry: |
9ae326a6 DH |
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: | |
9ae326a6 DH |
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; | |
82140443 | 725 | struct path path; |
9ae326a6 DH |
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 | ||
82140443 DH |
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; | |
9ae326a6 DH |
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; | |
627bf81a | 782 | if (!subdir->d_inode->i_op->setxattr || |
9ae326a6 DH |
783 | !subdir->d_inode->i_op->getxattr || |
784 | !subdir->d_inode->i_op->lookup || | |
785 | !subdir->d_inode->i_op->mkdir || | |
786 | !subdir->d_inode->i_op->create || | |
787 | !subdir->d_inode->i_op->rename || | |
788 | !subdir->d_inode->i_op->rmdir || | |
789 | !subdir->d_inode->i_op->unlink) | |
790 | goto check_error; | |
791 | ||
792 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
793 | return subdir; | |
794 | ||
795 | check_error: | |
796 | dput(subdir); | |
797 | _leave(" = %d [check]", ret); | |
798 | return ERR_PTR(ret); | |
799 | ||
800 | mkdir_error: | |
801 | mutex_unlock(&dir->d_inode->i_mutex); | |
802 | dput(subdir); | |
803 | kerror("mkdir %s failed with error %d", dirname, ret); | |
804 | return ERR_PTR(ret); | |
805 | ||
806 | lookup_error: | |
807 | mutex_unlock(&dir->d_inode->i_mutex); | |
808 | ret = PTR_ERR(subdir); | |
809 | kerror("Lookup %s failed with error %d", dirname, ret); | |
810 | return ERR_PTR(ret); | |
811 | ||
812 | nomem_d_alloc: | |
813 | mutex_unlock(&dir->d_inode->i_mutex); | |
814 | _leave(" = -ENOMEM"); | |
815 | return ERR_PTR(-ENOMEM); | |
816 | } | |
817 | ||
818 | /* | |
819 | * find out if an object is in use or not | |
820 | * - if finds object and it's not in use: | |
821 | * - returns a pointer to the object and a reference on it | |
822 | * - returns with the directory locked | |
823 | */ | |
824 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
825 | struct dentry *dir, | |
826 | char *filename) | |
827 | { | |
828 | struct cachefiles_object *object; | |
829 | struct rb_node *_n; | |
830 | struct dentry *victim; | |
831 | unsigned long start; | |
832 | int ret; | |
833 | ||
834 | //_enter(",%*.*s/,%s", | |
835 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
836 | ||
837 | /* look up the victim */ | |
6bd5e82b | 838 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
839 | |
840 | start = jiffies; | |
841 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
842 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
843 | if (IS_ERR(victim)) | |
844 | goto lookup_error; | |
845 | ||
846 | //_debug("victim -> %p %s", | |
847 | // victim, victim->d_inode ? "positive" : "negative"); | |
848 | ||
849 | /* if the object is no longer there then we probably retired the object | |
850 | * at the netfs's request whilst the cull was in progress | |
851 | */ | |
852 | if (!victim->d_inode) { | |
853 | mutex_unlock(&dir->d_inode->i_mutex); | |
854 | dput(victim); | |
855 | _leave(" = -ENOENT [absent]"); | |
856 | return ERR_PTR(-ENOENT); | |
857 | } | |
858 | ||
859 | /* check to see if we're using this object */ | |
860 | read_lock(&cache->active_lock); | |
861 | ||
862 | _n = cache->active_nodes.rb_node; | |
863 | ||
864 | while (_n) { | |
865 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
866 | ||
867 | if (object->dentry > victim) | |
868 | _n = _n->rb_left; | |
869 | else if (object->dentry < victim) | |
870 | _n = _n->rb_right; | |
871 | else | |
872 | goto object_in_use; | |
873 | } | |
874 | ||
875 | read_unlock(&cache->active_lock); | |
876 | ||
877 | //_leave(" = %p", victim); | |
878 | return victim; | |
879 | ||
880 | object_in_use: | |
881 | read_unlock(&cache->active_lock); | |
882 | mutex_unlock(&dir->d_inode->i_mutex); | |
883 | dput(victim); | |
884 | //_leave(" = -EBUSY [in use]"); | |
885 | return ERR_PTR(-EBUSY); | |
886 | ||
887 | lookup_error: | |
888 | mutex_unlock(&dir->d_inode->i_mutex); | |
889 | ret = PTR_ERR(victim); | |
890 | if (ret == -ENOENT) { | |
891 | /* file or dir now absent - probably retired by netfs */ | |
892 | _leave(" = -ESTALE [absent]"); | |
893 | return ERR_PTR(-ESTALE); | |
894 | } | |
895 | ||
896 | if (ret == -EIO) { | |
897 | cachefiles_io_error(cache, "Lookup failed"); | |
898 | } else if (ret != -ENOMEM) { | |
899 | kerror("Internal error: %d", ret); | |
900 | ret = -EIO; | |
901 | } | |
902 | ||
903 | _leave(" = %d", ret); | |
904 | return ERR_PTR(ret); | |
905 | } | |
906 | ||
907 | /* | |
908 | * cull an object if it's not in use | |
909 | * - called only by cache manager daemon | |
910 | */ | |
911 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
912 | char *filename) | |
913 | { | |
914 | struct dentry *victim; | |
915 | int ret; | |
916 | ||
917 | _enter(",%*.*s/,%s", | |
918 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
919 | ||
920 | victim = cachefiles_check_active(cache, dir, filename); | |
921 | if (IS_ERR(victim)) | |
922 | return PTR_ERR(victim); | |
923 | ||
924 | _debug("victim -> %p %s", | |
925 | victim, victim->d_inode ? "positive" : "negative"); | |
926 | ||
927 | /* okay... the victim is not being used so we can cull it | |
928 | * - start by marking it as stale | |
929 | */ | |
930 | _debug("victim is cullable"); | |
931 | ||
932 | ret = cachefiles_remove_object_xattr(cache, victim); | |
933 | if (ret < 0) | |
934 | goto error_unlock; | |
935 | ||
936 | /* actually remove the victim (drops the dir mutex) */ | |
937 | _debug("bury"); | |
938 | ||
c61ea31d | 939 | ret = cachefiles_bury_object(cache, dir, victim, false); |
9ae326a6 DH |
940 | if (ret < 0) |
941 | goto error; | |
942 | ||
943 | dput(victim); | |
944 | _leave(" = 0"); | |
945 | return 0; | |
946 | ||
947 | error_unlock: | |
948 | mutex_unlock(&dir->d_inode->i_mutex); | |
949 | error: | |
950 | dput(victim); | |
951 | if (ret == -ENOENT) { | |
952 | /* file or dir now absent - probably retired by netfs */ | |
953 | _leave(" = -ESTALE [absent]"); | |
954 | return -ESTALE; | |
955 | } | |
956 | ||
957 | if (ret != -ENOMEM) { | |
958 | kerror("Internal error: %d", ret); | |
959 | ret = -EIO; | |
960 | } | |
961 | ||
962 | _leave(" = %d", ret); | |
963 | return ret; | |
964 | } | |
965 | ||
966 | /* | |
967 | * find out if an object is in use or not | |
968 | * - called only by cache manager daemon | |
969 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
970 | */ | |
971 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
972 | char *filename) | |
973 | { | |
974 | struct dentry *victim; | |
975 | ||
976 | //_enter(",%*.*s/,%s", | |
977 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
978 | ||
979 | victim = cachefiles_check_active(cache, dir, filename); | |
980 | if (IS_ERR(victim)) | |
981 | return PTR_ERR(victim); | |
982 | ||
983 | mutex_unlock(&dir->d_inode->i_mutex); | |
984 | dput(victim); | |
985 | //_leave(" = 0"); | |
986 | return 0; | |
987 | } |