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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 | ||
4e1eb883 FF |
38 | pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id); |
39 | pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n", | |
caaef690 | 40 | prefix, object->fscache.state->name, |
8b8edefa | 41 | object->fscache.flags, work_busy(&object->fscache.work), |
c2d35bfe | 42 | object->fscache.events, object->fscache.event_mask); |
4e1eb883 | 43 | pr_err("%sops=%u inp=%u exc=%u\n", |
d0e27b78 DH |
44 | prefix, object->fscache.n_ops, object->fscache.n_in_progress, |
45 | object->fscache.n_exclusive); | |
4e1eb883 | 46 | pr_err("%sparent=%p\n", |
d0e27b78 DH |
47 | prefix, object->fscache.parent); |
48 | ||
49 | spin_lock(&object->fscache.lock); | |
50 | cookie = object->fscache.cookie; | |
51 | if (cookie) { | |
4e1eb883 | 52 | pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n", |
d0e27b78 DH |
53 | prefix, |
54 | object->fscache.cookie, | |
55 | object->fscache.cookie->parent, | |
56 | object->fscache.cookie->netfs_data, | |
57 | object->fscache.cookie->flags); | |
509bf24d | 58 | if (keybuf && cookie->def) |
d0e27b78 DH |
59 | keylen = cookie->def->get_key(cookie->netfs_data, keybuf, |
60 | CACHEFILES_KEYBUF_SIZE); | |
61 | else | |
62 | keylen = 0; | |
63 | } else { | |
4e1eb883 | 64 | pr_err("%scookie=NULL\n", prefix); |
d0e27b78 DH |
65 | keylen = 0; |
66 | } | |
67 | spin_unlock(&object->fscache.lock); | |
68 | ||
69 | if (keylen) { | |
4e1eb883 | 70 | pr_err("%skey=[%u] '", prefix, keylen); |
d0e27b78 | 71 | for (loop = 0; loop < keylen; loop++) |
4e1eb883 FF |
72 | pr_cont("%02x", keybuf[loop]); |
73 | pr_cont("'\n"); | |
d0e27b78 DH |
74 | } |
75 | } | |
76 | ||
77 | /* | |
78 | * dump debugging info about a pair of objects | |
79 | */ | |
80 | static noinline void cachefiles_printk_object(struct cachefiles_object *object, | |
81 | struct cachefiles_object *xobject) | |
82 | { | |
83 | u8 *keybuf; | |
84 | ||
85 | keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO); | |
86 | if (object) | |
87 | __cachefiles_printk_object(object, "", keybuf); | |
88 | if (xobject) | |
89 | __cachefiles_printk_object(xobject, "x", keybuf); | |
90 | kfree(keybuf); | |
91 | } | |
92 | ||
c61ea31d DH |
93 | /* |
94 | * mark the owner of a dentry, if there is one, to indicate that that dentry | |
95 | * has been preemptively deleted | |
96 | * - the caller must hold the i_mutex on the dentry's parent as required to | |
97 | * call vfs_unlink(), vfs_rmdir() or vfs_rename() | |
98 | */ | |
99 | static void cachefiles_mark_object_buried(struct cachefiles_cache *cache, | |
100 | struct dentry *dentry) | |
101 | { | |
102 | struct cachefiles_object *object; | |
103 | struct rb_node *p; | |
104 | ||
a455589f | 105 | _enter(",'%pd'", dentry); |
c61ea31d DH |
106 | |
107 | write_lock(&cache->active_lock); | |
108 | ||
109 | p = cache->active_nodes.rb_node; | |
110 | while (p) { | |
111 | object = rb_entry(p, struct cachefiles_object, active_node); | |
112 | if (object->dentry > dentry) | |
113 | p = p->rb_left; | |
114 | else if (object->dentry < dentry) | |
115 | p = p->rb_right; | |
116 | else | |
117 | goto found_dentry; | |
118 | } | |
119 | ||
120 | write_unlock(&cache->active_lock); | |
121 | _leave(" [no owner]"); | |
122 | return; | |
123 | ||
124 | /* found the dentry for */ | |
125 | found_dentry: | |
126 | kdebug("preemptive burial: OBJ%x [%s] %p", | |
127 | object->fscache.debug_id, | |
caaef690 | 128 | object->fscache.state->name, |
c61ea31d DH |
129 | dentry); |
130 | ||
493f7bc1 | 131 | if (fscache_object_is_live(&object->fscache)) { |
4e1eb883 | 132 | pr_err("\n"); |
0227d6ab | 133 | pr_err("Error: Can't preemptively bury live object\n"); |
c61ea31d DH |
134 | cachefiles_printk_object(object, NULL); |
135 | } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { | |
0227d6ab | 136 | pr_err("Error: Object already preemptively buried\n"); |
c61ea31d DH |
137 | } |
138 | ||
139 | write_unlock(&cache->active_lock); | |
140 | _leave(" [owner marked]"); | |
141 | } | |
142 | ||
9ae326a6 DH |
143 | /* |
144 | * record the fact that an object is now active | |
145 | */ | |
fee096de DH |
146 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
147 | struct cachefiles_object *object) | |
9ae326a6 DH |
148 | { |
149 | struct cachefiles_object *xobject; | |
150 | struct rb_node **_p, *_parent = NULL; | |
151 | struct dentry *dentry; | |
152 | ||
153 | _enter(",%p", object); | |
154 | ||
155 | try_again: | |
156 | write_lock(&cache->active_lock); | |
157 | ||
d0e27b78 | 158 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
0227d6ab | 159 | pr_err("Error: Object already active\n"); |
d0e27b78 | 160 | cachefiles_printk_object(object, NULL); |
9ae326a6 | 161 | BUG(); |
d0e27b78 | 162 | } |
9ae326a6 DH |
163 | |
164 | dentry = object->dentry; | |
165 | _p = &cache->active_nodes.rb_node; | |
166 | while (*_p) { | |
167 | _parent = *_p; | |
168 | xobject = rb_entry(_parent, | |
169 | struct cachefiles_object, active_node); | |
170 | ||
171 | ASSERT(xobject != object); | |
172 | ||
173 | if (xobject->dentry > dentry) | |
174 | _p = &(*_p)->rb_left; | |
175 | else if (xobject->dentry < dentry) | |
176 | _p = &(*_p)->rb_right; | |
177 | else | |
178 | goto wait_for_old_object; | |
179 | } | |
180 | ||
181 | rb_link_node(&object->active_node, _parent, _p); | |
182 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
183 | ||
184 | write_unlock(&cache->active_lock); | |
fee096de DH |
185 | _leave(" = 0"); |
186 | return 0; | |
9ae326a6 DH |
187 | |
188 | /* an old object from a previous incarnation is hogging the slot - we | |
189 | * need to wait for it to be destroyed */ | |
190 | wait_for_old_object: | |
a30efe26 | 191 | if (fscache_object_is_live(&xobject->fscache)) { |
4e1eb883 | 192 | pr_err("\n"); |
0227d6ab | 193 | pr_err("Error: Unexpected object collision\n"); |
d0e27b78 | 194 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
195 | BUG(); |
196 | } | |
197 | atomic_inc(&xobject->usage); | |
198 | write_unlock(&cache->active_lock); | |
199 | ||
fee096de DH |
200 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
201 | wait_queue_head_t *wq; | |
202 | ||
203 | signed long timeout = 60 * HZ; | |
204 | wait_queue_t wait; | |
205 | bool requeue; | |
206 | ||
207 | /* if the object we're waiting for is queued for processing, | |
208 | * then just put ourselves on the queue behind it */ | |
8b8edefa | 209 | if (work_pending(&xobject->fscache.work)) { |
fee096de DH |
210 | _debug("queue OBJ%x behind OBJ%x immediately", |
211 | object->fscache.debug_id, | |
212 | xobject->fscache.debug_id); | |
213 | goto requeue; | |
214 | } | |
215 | ||
216 | /* otherwise we sleep until either the object we're waiting for | |
8b8edefa | 217 | * is done, or the fscache_object is congested */ |
fee096de DH |
218 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); |
219 | init_wait(&wait); | |
220 | requeue = false; | |
221 | do { | |
222 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
223 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
224 | break; | |
8b8edefa TH |
225 | |
226 | requeue = fscache_object_sleep_till_congested(&timeout); | |
fee096de DH |
227 | } while (timeout > 0 && !requeue); |
228 | finish_wait(wq, &wait); | |
229 | ||
230 | if (requeue && | |
231 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
232 | _debug("queue OBJ%x behind OBJ%x after wait", | |
233 | object->fscache.debug_id, | |
234 | xobject->fscache.debug_id); | |
235 | goto requeue; | |
236 | } | |
237 | ||
238 | if (timeout <= 0) { | |
4e1eb883 | 239 | pr_err("\n"); |
0227d6ab | 240 | pr_err("Error: Overlong wait for old active object to go away\n"); |
fee096de DH |
241 | cachefiles_printk_object(object, xobject); |
242 | goto requeue; | |
243 | } | |
244 | } | |
245 | ||
246 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
9ae326a6 DH |
247 | |
248 | cache->cache.ops->put_object(&xobject->fscache); | |
249 | goto try_again; | |
fee096de DH |
250 | |
251 | requeue: | |
252 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
253 | cache->cache.ops->put_object(&xobject->fscache); | |
254 | _leave(" = -ETIMEDOUT"); | |
255 | return -ETIMEDOUT; | |
9ae326a6 DH |
256 | } |
257 | ||
258 | /* | |
259 | * delete an object representation from the cache | |
260 | * - file backed objects are unlinked | |
261 | * - directory backed objects are stuffed into the graveyard for userspace to | |
262 | * delete | |
263 | * - unlocks the directory mutex | |
264 | */ | |
265 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
266 | struct dentry *dir, | |
c61ea31d DH |
267 | struct dentry *rep, |
268 | bool preemptive) | |
9ae326a6 DH |
269 | { |
270 | struct dentry *grave, *trap; | |
82140443 | 271 | struct path path, path_to_graveyard; |
9ae326a6 DH |
272 | char nbuffer[8 + 8 + 1]; |
273 | int ret; | |
274 | ||
a455589f | 275 | _enter(",'%pd','%pd'", dir, rep); |
9ae326a6 | 276 | |
c61ea31d DH |
277 | _debug("remove %p from %p", rep, dir); |
278 | ||
9ae326a6 DH |
279 | /* non-directories can just be unlinked */ |
280 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
281 | _debug("unlink stale object"); | |
9ae326a6 | 282 | |
82140443 DH |
283 | path.mnt = cache->mnt; |
284 | path.dentry = dir; | |
285 | ret = security_path_unlink(&path, rep); | |
286 | if (ret < 0) { | |
287 | cachefiles_io_error(cache, "Unlink security error"); | |
288 | } else { | |
b21996e3 | 289 | ret = vfs_unlink(dir->d_inode, rep, NULL); |
82140443 DH |
290 | |
291 | if (preemptive) | |
292 | cachefiles_mark_object_buried(cache, rep); | |
293 | } | |
c61ea31d | 294 | |
9ae326a6 DH |
295 | mutex_unlock(&dir->d_inode->i_mutex); |
296 | ||
297 | if (ret == -EIO) | |
298 | cachefiles_io_error(cache, "Unlink failed"); | |
299 | ||
300 | _leave(" = %d", ret); | |
301 | return ret; | |
302 | } | |
303 | ||
304 | /* directories have to be moved to the graveyard */ | |
305 | _debug("move stale object to graveyard"); | |
306 | mutex_unlock(&dir->d_inode->i_mutex); | |
307 | ||
308 | try_again: | |
309 | /* first step is to make up a grave dentry in the graveyard */ | |
310 | sprintf(nbuffer, "%08x%08x", | |
311 | (uint32_t) get_seconds(), | |
312 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
313 | ||
314 | /* do the multiway lock magic */ | |
315 | trap = lock_rename(cache->graveyard, dir); | |
316 | ||
317 | /* do some checks before getting the grave dentry */ | |
318 | if (rep->d_parent != dir) { | |
319 | /* the entry was probably culled when we dropped the parent dir | |
320 | * lock */ | |
321 | unlock_rename(cache->graveyard, dir); | |
322 | _leave(" = 0 [culled?]"); | |
323 | return 0; | |
324 | } | |
325 | ||
326 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { | |
327 | unlock_rename(cache->graveyard, dir); | |
328 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
329 | return -EIO; | |
330 | } | |
331 | ||
332 | if (trap == rep) { | |
333 | unlock_rename(cache->graveyard, dir); | |
334 | cachefiles_io_error(cache, "May not make directory loop"); | |
335 | return -EIO; | |
336 | } | |
337 | ||
338 | if (d_mountpoint(rep)) { | |
339 | unlock_rename(cache->graveyard, dir); | |
340 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
341 | return -EIO; | |
342 | } | |
343 | ||
344 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
345 | if (IS_ERR(grave)) { | |
346 | unlock_rename(cache->graveyard, dir); | |
347 | ||
348 | if (PTR_ERR(grave) == -ENOMEM) { | |
349 | _leave(" = -ENOMEM"); | |
350 | return -ENOMEM; | |
351 | } | |
352 | ||
353 | cachefiles_io_error(cache, "Lookup error %ld", | |
354 | PTR_ERR(grave)); | |
355 | return -EIO; | |
356 | } | |
357 | ||
358 | if (grave->d_inode) { | |
359 | unlock_rename(cache->graveyard, dir); | |
360 | dput(grave); | |
361 | grave = NULL; | |
362 | cond_resched(); | |
363 | goto try_again; | |
364 | } | |
365 | ||
366 | if (d_mountpoint(grave)) { | |
367 | unlock_rename(cache->graveyard, dir); | |
368 | dput(grave); | |
369 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
370 | return -EIO; | |
371 | } | |
372 | ||
373 | /* target should not be an ancestor of source */ | |
374 | if (trap == grave) { | |
375 | unlock_rename(cache->graveyard, dir); | |
376 | dput(grave); | |
377 | cachefiles_io_error(cache, "May not make directory loop"); | |
378 | return -EIO; | |
379 | } | |
380 | ||
381 | /* attempt the rename */ | |
82140443 DH |
382 | path.mnt = cache->mnt; |
383 | path.dentry = dir; | |
384 | path_to_graveyard.mnt = cache->mnt; | |
385 | path_to_graveyard.dentry = cache->graveyard; | |
0b3974eb | 386 | ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); |
82140443 DH |
387 | if (ret < 0) { |
388 | cachefiles_io_error(cache, "Rename security error %d", ret); | |
389 | } else { | |
390 | ret = vfs_rename(dir->d_inode, rep, | |
520c8b16 | 391 | cache->graveyard->d_inode, grave, NULL, 0); |
82140443 DH |
392 | if (ret != 0 && ret != -ENOMEM) |
393 | cachefiles_io_error(cache, | |
394 | "Rename failed with error %d", ret); | |
9ae326a6 | 395 | |
82140443 DH |
396 | if (preemptive) |
397 | cachefiles_mark_object_buried(cache, rep); | |
398 | } | |
c61ea31d | 399 | |
9ae326a6 DH |
400 | unlock_rename(cache->graveyard, dir); |
401 | dput(grave); | |
402 | _leave(" = 0"); | |
403 | return 0; | |
404 | } | |
405 | ||
406 | /* | |
407 | * delete an object representation from the cache | |
408 | */ | |
409 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
410 | struct cachefiles_object *object) | |
411 | { | |
412 | struct dentry *dir; | |
413 | int ret; | |
414 | ||
c61ea31d | 415 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); |
9ae326a6 DH |
416 | |
417 | ASSERT(object->dentry); | |
418 | ASSERT(object->dentry->d_inode); | |
419 | ASSERT(object->dentry->d_parent); | |
420 | ||
421 | dir = dget_parent(object->dentry); | |
422 | ||
6511de33 | 423 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae | 424 | |
c61ea31d DH |
425 | if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { |
426 | /* object allocation for the same key preemptively deleted this | |
427 | * object's file so that it could create its own file */ | |
428 | _debug("object preemptively buried"); | |
8f9941ae DH |
429 | mutex_unlock(&dir->d_inode->i_mutex); |
430 | ret = 0; | |
c61ea31d DH |
431 | } else { |
432 | /* we need to check that our parent is _still_ our parent - it | |
433 | * may have been renamed */ | |
434 | if (dir == object->dentry->d_parent) { | |
435 | ret = cachefiles_bury_object(cache, dir, | |
436 | object->dentry, false); | |
437 | } else { | |
438 | /* it got moved, presumably by cachefilesd culling it, | |
439 | * so it's no longer in the key path and we can ignore | |
440 | * it */ | |
441 | mutex_unlock(&dir->d_inode->i_mutex); | |
442 | ret = 0; | |
443 | } | |
8f9941ae | 444 | } |
9ae326a6 DH |
445 | |
446 | dput(dir); | |
447 | _leave(" = %d", ret); | |
448 | return ret; | |
449 | } | |
450 | ||
451 | /* | |
452 | * walk from the parent object to the child object through the backing | |
453 | * filesystem, creating directories as we go | |
454 | */ | |
455 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
456 | struct cachefiles_object *object, | |
457 | const char *key, | |
458 | struct cachefiles_xattr *auxdata) | |
459 | { | |
460 | struct cachefiles_cache *cache; | |
461 | struct dentry *dir, *next = NULL; | |
82140443 | 462 | struct path path; |
9ae326a6 DH |
463 | unsigned long start; |
464 | const char *name; | |
465 | int ret, nlen; | |
466 | ||
c61ea31d DH |
467 | _enter("OBJ%x{%p},OBJ%x,%s,", |
468 | parent->fscache.debug_id, parent->dentry, | |
469 | object->fscache.debug_id, key); | |
9ae326a6 DH |
470 | |
471 | cache = container_of(parent->fscache.cache, | |
472 | struct cachefiles_cache, cache); | |
82140443 | 473 | path.mnt = cache->mnt; |
9ae326a6 DH |
474 | |
475 | ASSERT(parent->dentry); | |
476 | ASSERT(parent->dentry->d_inode); | |
477 | ||
478 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { | |
479 | // TODO: convert file to dir | |
480 | _leave("looking up in none directory"); | |
481 | return -ENOBUFS; | |
482 | } | |
483 | ||
484 | dir = dget(parent->dentry); | |
485 | ||
486 | advance: | |
487 | /* attempt to transit the first directory component */ | |
488 | name = key; | |
489 | nlen = strlen(key); | |
490 | ||
491 | /* key ends in a double NUL */ | |
492 | key = key + nlen + 1; | |
493 | if (!*key) | |
494 | key = NULL; | |
495 | ||
496 | lookup_again: | |
497 | /* search the current directory for the element name */ | |
498 | _debug("lookup '%s'", name); | |
499 | ||
6511de33 | 500 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
501 | |
502 | start = jiffies; | |
503 | next = lookup_one_len(name, dir, nlen); | |
504 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
505 | if (IS_ERR(next)) | |
506 | goto lookup_error; | |
507 | ||
508 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); | |
509 | ||
510 | if (!key) | |
511 | object->new = !next->d_inode; | |
512 | ||
513 | /* if this element of the path doesn't exist, then the lookup phase | |
514 | * failed, and we can release any readers in the certain knowledge that | |
515 | * there's nothing for them to actually read */ | |
516 | if (!next->d_inode) | |
517 | fscache_object_lookup_negative(&object->fscache); | |
518 | ||
519 | /* we need to create the object if it's negative */ | |
520 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
521 | /* index objects and intervening tree levels must be subdirs */ | |
522 | if (!next->d_inode) { | |
523 | ret = cachefiles_has_space(cache, 1, 0); | |
524 | if (ret < 0) | |
525 | goto create_error; | |
526 | ||
82140443 DH |
527 | path.dentry = dir; |
528 | ret = security_path_mkdir(&path, next, 0); | |
529 | if (ret < 0) | |
530 | goto create_error; | |
9ae326a6 DH |
531 | start = jiffies; |
532 | ret = vfs_mkdir(dir->d_inode, next, 0); | |
533 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
534 | if (ret < 0) | |
535 | goto create_error; | |
536 | ||
537 | ASSERT(next->d_inode); | |
538 | ||
539 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
540 | next, next->d_inode, next->d_inode->i_ino); | |
541 | ||
542 | } else if (!S_ISDIR(next->d_inode->i_mode)) { | |
6ff66ac7 | 543 | pr_err("inode %lu is not a directory\n", |
9ae326a6 DH |
544 | next->d_inode->i_ino); |
545 | ret = -ENOBUFS; | |
546 | goto error; | |
547 | } | |
548 | ||
549 | } else { | |
550 | /* non-index objects start out life as files */ | |
551 | if (!next->d_inode) { | |
552 | ret = cachefiles_has_space(cache, 1, 0); | |
553 | if (ret < 0) | |
554 | goto create_error; | |
555 | ||
82140443 DH |
556 | path.dentry = dir; |
557 | ret = security_path_mknod(&path, next, S_IFREG, 0); | |
558 | if (ret < 0) | |
559 | goto create_error; | |
9ae326a6 | 560 | start = jiffies; |
312b63fb | 561 | ret = vfs_create(dir->d_inode, next, S_IFREG, true); |
9ae326a6 DH |
562 | cachefiles_hist(cachefiles_create_histogram, start); |
563 | if (ret < 0) | |
564 | goto create_error; | |
565 | ||
566 | ASSERT(next->d_inode); | |
567 | ||
568 | _debug("create -> %p{%p{ino=%lu}}", | |
569 | next, next->d_inode, next->d_inode->i_ino); | |
570 | ||
571 | } else if (!S_ISDIR(next->d_inode->i_mode) && | |
572 | !S_ISREG(next->d_inode->i_mode) | |
573 | ) { | |
6ff66ac7 | 574 | pr_err("inode %lu is not a file or directory\n", |
9ae326a6 DH |
575 | next->d_inode->i_ino); |
576 | ret = -ENOBUFS; | |
577 | goto error; | |
578 | } | |
579 | } | |
580 | ||
581 | /* process the next component */ | |
582 | if (key) { | |
583 | _debug("advance"); | |
584 | mutex_unlock(&dir->d_inode->i_mutex); | |
585 | dput(dir); | |
586 | dir = next; | |
587 | next = NULL; | |
588 | goto advance; | |
589 | } | |
590 | ||
591 | /* we've found the object we were looking for */ | |
592 | object->dentry = next; | |
593 | ||
594 | /* if we've found that the terminal object exists, then we need to | |
595 | * check its attributes and delete it if it's out of date */ | |
596 | if (!object->new) { | |
a455589f | 597 | _debug("validate '%pd'", next); |
9ae326a6 DH |
598 | |
599 | ret = cachefiles_check_object_xattr(object, auxdata); | |
600 | if (ret == -ESTALE) { | |
601 | /* delete the object (the deleter drops the directory | |
602 | * mutex) */ | |
603 | object->dentry = NULL; | |
604 | ||
c61ea31d | 605 | ret = cachefiles_bury_object(cache, dir, next, true); |
9ae326a6 DH |
606 | dput(next); |
607 | next = NULL; | |
608 | ||
609 | if (ret < 0) | |
610 | goto delete_error; | |
611 | ||
612 | _debug("redo lookup"); | |
613 | goto lookup_again; | |
614 | } | |
615 | } | |
616 | ||
617 | /* note that we're now using this object */ | |
fee096de | 618 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
619 | |
620 | mutex_unlock(&dir->d_inode->i_mutex); | |
621 | dput(dir); | |
622 | dir = NULL; | |
623 | ||
fee096de DH |
624 | if (ret == -ETIMEDOUT) |
625 | goto mark_active_timed_out; | |
626 | ||
9ae326a6 DH |
627 | _debug("=== OBTAINED_OBJECT ==="); |
628 | ||
629 | if (object->new) { | |
630 | /* attach data to a newly constructed terminal object */ | |
631 | ret = cachefiles_set_object_xattr(object, auxdata); | |
632 | if (ret < 0) | |
633 | goto check_error; | |
634 | } else { | |
635 | /* always update the atime on an object we've just looked up | |
636 | * (this is used to keep track of culling, and atimes are only | |
637 | * updated by read, write and readdir but not lookup or | |
638 | * open) */ | |
68ac1234 AV |
639 | path.dentry = next; |
640 | touch_atime(&path); | |
9ae326a6 DH |
641 | } |
642 | ||
643 | /* open a file interface onto a data file */ | |
644 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
645 | if (S_ISREG(object->dentry->d_inode->i_mode)) { | |
646 | const struct address_space_operations *aops; | |
647 | ||
648 | ret = -EPERM; | |
649 | aops = object->dentry->d_inode->i_mapping->a_ops; | |
650 | if (!aops->bmap) | |
651 | goto check_error; | |
652 | ||
653 | object->backer = object->dentry; | |
654 | } else { | |
655 | BUG(); // TODO: open file in data-class subdir | |
656 | } | |
657 | } | |
658 | ||
659 | object->new = 0; | |
660 | fscache_obtained_object(&object->fscache); | |
661 | ||
662 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); | |
663 | return 0; | |
664 | ||
665 | create_error: | |
666 | _debug("create error %d", ret); | |
667 | if (ret == -EIO) | |
668 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
669 | goto error; | |
670 | ||
fee096de DH |
671 | mark_active_timed_out: |
672 | _debug("mark active timed out"); | |
673 | goto release_dentry; | |
674 | ||
9ae326a6 DH |
675 | check_error: |
676 | _debug("check error %d", ret); | |
677 | write_lock(&cache->active_lock); | |
678 | rb_erase(&object->active_node, &cache->active_nodes); | |
679 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
680 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
681 | write_unlock(&cache->active_lock); | |
fee096de | 682 | release_dentry: |
9ae326a6 DH |
683 | dput(object->dentry); |
684 | object->dentry = NULL; | |
685 | goto error_out; | |
686 | ||
687 | delete_error: | |
688 | _debug("delete error %d", ret); | |
689 | goto error_out2; | |
690 | ||
691 | lookup_error: | |
692 | _debug("lookup error %ld", PTR_ERR(next)); | |
693 | ret = PTR_ERR(next); | |
694 | if (ret == -EIO) | |
695 | cachefiles_io_error(cache, "Lookup failed"); | |
696 | next = NULL; | |
697 | error: | |
698 | mutex_unlock(&dir->d_inode->i_mutex); | |
699 | dput(next); | |
700 | error_out2: | |
701 | dput(dir); | |
702 | error_out: | |
9ae326a6 DH |
703 | _leave(" = error %d", -ret); |
704 | return ret; | |
705 | } | |
706 | ||
707 | /* | |
708 | * get a subdirectory | |
709 | */ | |
710 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
711 | struct dentry *dir, | |
712 | const char *dirname) | |
713 | { | |
714 | struct dentry *subdir; | |
715 | unsigned long start; | |
82140443 | 716 | struct path path; |
9ae326a6 DH |
717 | int ret; |
718 | ||
719 | _enter(",,%s", dirname); | |
720 | ||
721 | /* search the current directory for the element name */ | |
722 | mutex_lock(&dir->d_inode->i_mutex); | |
723 | ||
724 | start = jiffies; | |
725 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
726 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
727 | if (IS_ERR(subdir)) { | |
728 | if (PTR_ERR(subdir) == -ENOMEM) | |
729 | goto nomem_d_alloc; | |
730 | goto lookup_error; | |
731 | } | |
732 | ||
733 | _debug("subdir -> %p %s", | |
734 | subdir, subdir->d_inode ? "positive" : "negative"); | |
735 | ||
736 | /* we need to create the subdir if it doesn't exist yet */ | |
737 | if (!subdir->d_inode) { | |
738 | ret = cachefiles_has_space(cache, 1, 0); | |
739 | if (ret < 0) | |
740 | goto mkdir_error; | |
741 | ||
742 | _debug("attempt mkdir"); | |
743 | ||
82140443 DH |
744 | path.mnt = cache->mnt; |
745 | path.dentry = dir; | |
746 | ret = security_path_mkdir(&path, subdir, 0700); | |
747 | if (ret < 0) | |
748 | goto mkdir_error; | |
9ae326a6 DH |
749 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); |
750 | if (ret < 0) | |
751 | goto mkdir_error; | |
752 | ||
753 | ASSERT(subdir->d_inode); | |
754 | ||
755 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
756 | subdir, | |
757 | subdir->d_inode, | |
758 | subdir->d_inode->i_ino); | |
759 | } | |
760 | ||
761 | mutex_unlock(&dir->d_inode->i_mutex); | |
762 | ||
763 | /* we need to make sure the subdir is a directory */ | |
764 | ASSERT(subdir->d_inode); | |
765 | ||
766 | if (!S_ISDIR(subdir->d_inode->i_mode)) { | |
6ff66ac7 | 767 | pr_err("%s is not a directory\n", dirname); |
9ae326a6 DH |
768 | ret = -EIO; |
769 | goto check_error; | |
770 | } | |
771 | ||
772 | ret = -EPERM; | |
627bf81a | 773 | if (!subdir->d_inode->i_op->setxattr || |
9ae326a6 DH |
774 | !subdir->d_inode->i_op->getxattr || |
775 | !subdir->d_inode->i_op->lookup || | |
776 | !subdir->d_inode->i_op->mkdir || | |
777 | !subdir->d_inode->i_op->create || | |
e2cf1f1c DH |
778 | (!subdir->d_inode->i_op->rename && |
779 | !subdir->d_inode->i_op->rename2) || | |
9ae326a6 DH |
780 | !subdir->d_inode->i_op->rmdir || |
781 | !subdir->d_inode->i_op->unlink) | |
782 | goto check_error; | |
783 | ||
784 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
785 | return subdir; | |
786 | ||
787 | check_error: | |
788 | dput(subdir); | |
789 | _leave(" = %d [check]", ret); | |
790 | return ERR_PTR(ret); | |
791 | ||
792 | mkdir_error: | |
793 | mutex_unlock(&dir->d_inode->i_mutex); | |
794 | dput(subdir); | |
6ff66ac7 | 795 | pr_err("mkdir %s failed with error %d\n", dirname, ret); |
9ae326a6 DH |
796 | return ERR_PTR(ret); |
797 | ||
798 | lookup_error: | |
799 | mutex_unlock(&dir->d_inode->i_mutex); | |
800 | ret = PTR_ERR(subdir); | |
6ff66ac7 | 801 | pr_err("Lookup %s failed with error %d\n", dirname, ret); |
9ae326a6 DH |
802 | return ERR_PTR(ret); |
803 | ||
804 | nomem_d_alloc: | |
805 | mutex_unlock(&dir->d_inode->i_mutex); | |
806 | _leave(" = -ENOMEM"); | |
807 | return ERR_PTR(-ENOMEM); | |
808 | } | |
809 | ||
810 | /* | |
811 | * find out if an object is in use or not | |
812 | * - if finds object and it's not in use: | |
813 | * - returns a pointer to the object and a reference on it | |
814 | * - returns with the directory locked | |
815 | */ | |
816 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
817 | struct dentry *dir, | |
818 | char *filename) | |
819 | { | |
820 | struct cachefiles_object *object; | |
821 | struct rb_node *_n; | |
822 | struct dentry *victim; | |
823 | unsigned long start; | |
824 | int ret; | |
825 | ||
a455589f AV |
826 | //_enter(",%pd/,%s", |
827 | // dir, filename); | |
9ae326a6 DH |
828 | |
829 | /* look up the victim */ | |
6bd5e82b | 830 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
831 | |
832 | start = jiffies; | |
833 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
834 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
835 | if (IS_ERR(victim)) | |
836 | goto lookup_error; | |
837 | ||
838 | //_debug("victim -> %p %s", | |
839 | // victim, victim->d_inode ? "positive" : "negative"); | |
840 | ||
841 | /* if the object is no longer there then we probably retired the object | |
842 | * at the netfs's request whilst the cull was in progress | |
843 | */ | |
844 | if (!victim->d_inode) { | |
845 | mutex_unlock(&dir->d_inode->i_mutex); | |
846 | dput(victim); | |
847 | _leave(" = -ENOENT [absent]"); | |
848 | return ERR_PTR(-ENOENT); | |
849 | } | |
850 | ||
851 | /* check to see if we're using this object */ | |
852 | read_lock(&cache->active_lock); | |
853 | ||
854 | _n = cache->active_nodes.rb_node; | |
855 | ||
856 | while (_n) { | |
857 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
858 | ||
859 | if (object->dentry > victim) | |
860 | _n = _n->rb_left; | |
861 | else if (object->dentry < victim) | |
862 | _n = _n->rb_right; | |
863 | else | |
864 | goto object_in_use; | |
865 | } | |
866 | ||
867 | read_unlock(&cache->active_lock); | |
868 | ||
869 | //_leave(" = %p", victim); | |
870 | return victim; | |
871 | ||
872 | object_in_use: | |
873 | read_unlock(&cache->active_lock); | |
874 | mutex_unlock(&dir->d_inode->i_mutex); | |
875 | dput(victim); | |
876 | //_leave(" = -EBUSY [in use]"); | |
877 | return ERR_PTR(-EBUSY); | |
878 | ||
879 | lookup_error: | |
880 | mutex_unlock(&dir->d_inode->i_mutex); | |
881 | ret = PTR_ERR(victim); | |
882 | if (ret == -ENOENT) { | |
883 | /* file or dir now absent - probably retired by netfs */ | |
884 | _leave(" = -ESTALE [absent]"); | |
885 | return ERR_PTR(-ESTALE); | |
886 | } | |
887 | ||
888 | if (ret == -EIO) { | |
889 | cachefiles_io_error(cache, "Lookup failed"); | |
890 | } else if (ret != -ENOMEM) { | |
6ff66ac7 | 891 | pr_err("Internal error: %d\n", ret); |
9ae326a6 DH |
892 | ret = -EIO; |
893 | } | |
894 | ||
895 | _leave(" = %d", ret); | |
896 | return ERR_PTR(ret); | |
897 | } | |
898 | ||
899 | /* | |
900 | * cull an object if it's not in use | |
901 | * - called only by cache manager daemon | |
902 | */ | |
903 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
904 | char *filename) | |
905 | { | |
906 | struct dentry *victim; | |
907 | int ret; | |
908 | ||
a455589f | 909 | _enter(",%pd/,%s", dir, filename); |
9ae326a6 DH |
910 | |
911 | victim = cachefiles_check_active(cache, dir, filename); | |
912 | if (IS_ERR(victim)) | |
913 | return PTR_ERR(victim); | |
914 | ||
915 | _debug("victim -> %p %s", | |
916 | victim, victim->d_inode ? "positive" : "negative"); | |
917 | ||
918 | /* okay... the victim is not being used so we can cull it | |
919 | * - start by marking it as stale | |
920 | */ | |
921 | _debug("victim is cullable"); | |
922 | ||
923 | ret = cachefiles_remove_object_xattr(cache, victim); | |
924 | if (ret < 0) | |
925 | goto error_unlock; | |
926 | ||
927 | /* actually remove the victim (drops the dir mutex) */ | |
928 | _debug("bury"); | |
929 | ||
c61ea31d | 930 | ret = cachefiles_bury_object(cache, dir, victim, false); |
9ae326a6 DH |
931 | if (ret < 0) |
932 | goto error; | |
933 | ||
934 | dput(victim); | |
935 | _leave(" = 0"); | |
936 | return 0; | |
937 | ||
938 | error_unlock: | |
939 | mutex_unlock(&dir->d_inode->i_mutex); | |
940 | error: | |
941 | dput(victim); | |
942 | if (ret == -ENOENT) { | |
943 | /* file or dir now absent - probably retired by netfs */ | |
944 | _leave(" = -ESTALE [absent]"); | |
945 | return -ESTALE; | |
946 | } | |
947 | ||
948 | if (ret != -ENOMEM) { | |
6ff66ac7 | 949 | pr_err("Internal error: %d\n", ret); |
9ae326a6 DH |
950 | ret = -EIO; |
951 | } | |
952 | ||
953 | _leave(" = %d", ret); | |
954 | return ret; | |
955 | } | |
956 | ||
957 | /* | |
958 | * find out if an object is in use or not | |
959 | * - called only by cache manager daemon | |
960 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
961 | */ | |
962 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
963 | char *filename) | |
964 | { | |
965 | struct dentry *victim; | |
966 | ||
a455589f AV |
967 | //_enter(",%pd/,%s", |
968 | // dir, filename); | |
9ae326a6 DH |
969 | |
970 | victim = cachefiles_check_active(cache, dir, filename); | |
971 | if (IS_ERR(victim)) | |
972 | return PTR_ERR(victim); | |
973 | ||
974 | mutex_unlock(&dir->d_inode->i_mutex); | |
975 | dput(victim); | |
976 | //_leave(" = 0"); | |
977 | return 0; | |
978 | } |