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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 | ||
105 | _enter(",'%*.*s'", | |
106 | dentry->d_name.len, dentry->d_name.len, dentry->d_name.name); | |
107 | ||
108 | write_lock(&cache->active_lock); | |
109 | ||
110 | p = cache->active_nodes.rb_node; | |
111 | while (p) { | |
112 | object = rb_entry(p, struct cachefiles_object, active_node); | |
113 | if (object->dentry > dentry) | |
114 | p = p->rb_left; | |
115 | else if (object->dentry < dentry) | |
116 | p = p->rb_right; | |
117 | else | |
118 | goto found_dentry; | |
119 | } | |
120 | ||
121 | write_unlock(&cache->active_lock); | |
122 | _leave(" [no owner]"); | |
123 | return; | |
124 | ||
125 | /* found the dentry for */ | |
126 | found_dentry: | |
127 | kdebug("preemptive burial: OBJ%x [%s] %p", | |
128 | object->fscache.debug_id, | |
caaef690 | 129 | object->fscache.state->name, |
c61ea31d DH |
130 | dentry); |
131 | ||
493f7bc1 | 132 | if (fscache_object_is_live(&object->fscache)) { |
4e1eb883 | 133 | pr_err("\n"); |
0227d6ab | 134 | pr_err("Error: Can't preemptively bury live object\n"); |
c61ea31d DH |
135 | cachefiles_printk_object(object, NULL); |
136 | } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { | |
0227d6ab | 137 | pr_err("Error: Object already preemptively buried\n"); |
c61ea31d DH |
138 | } |
139 | ||
140 | write_unlock(&cache->active_lock); | |
141 | _leave(" [owner marked]"); | |
142 | } | |
143 | ||
9ae326a6 DH |
144 | /* |
145 | * record the fact that an object is now active | |
146 | */ | |
fee096de DH |
147 | static int cachefiles_mark_object_active(struct cachefiles_cache *cache, |
148 | struct cachefiles_object *object) | |
9ae326a6 DH |
149 | { |
150 | struct cachefiles_object *xobject; | |
151 | struct rb_node **_p, *_parent = NULL; | |
152 | struct dentry *dentry; | |
153 | ||
154 | _enter(",%p", object); | |
155 | ||
156 | try_again: | |
157 | write_lock(&cache->active_lock); | |
158 | ||
d0e27b78 | 159 | if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) { |
0227d6ab | 160 | pr_err("Error: Object already active\n"); |
d0e27b78 | 161 | cachefiles_printk_object(object, NULL); |
9ae326a6 | 162 | BUG(); |
d0e27b78 | 163 | } |
9ae326a6 DH |
164 | |
165 | dentry = object->dentry; | |
166 | _p = &cache->active_nodes.rb_node; | |
167 | while (*_p) { | |
168 | _parent = *_p; | |
169 | xobject = rb_entry(_parent, | |
170 | struct cachefiles_object, active_node); | |
171 | ||
172 | ASSERT(xobject != object); | |
173 | ||
174 | if (xobject->dentry > dentry) | |
175 | _p = &(*_p)->rb_left; | |
176 | else if (xobject->dentry < dentry) | |
177 | _p = &(*_p)->rb_right; | |
178 | else | |
179 | goto wait_for_old_object; | |
180 | } | |
181 | ||
182 | rb_link_node(&object->active_node, _parent, _p); | |
183 | rb_insert_color(&object->active_node, &cache->active_nodes); | |
184 | ||
185 | write_unlock(&cache->active_lock); | |
fee096de DH |
186 | _leave(" = 0"); |
187 | return 0; | |
9ae326a6 DH |
188 | |
189 | /* an old object from a previous incarnation is hogging the slot - we | |
190 | * need to wait for it to be destroyed */ | |
191 | wait_for_old_object: | |
a30efe26 | 192 | if (fscache_object_is_live(&xobject->fscache)) { |
4e1eb883 | 193 | pr_err("\n"); |
0227d6ab | 194 | pr_err("Error: Unexpected object collision\n"); |
d0e27b78 | 195 | cachefiles_printk_object(object, xobject); |
9ae326a6 DH |
196 | BUG(); |
197 | } | |
198 | atomic_inc(&xobject->usage); | |
199 | write_unlock(&cache->active_lock); | |
200 | ||
fee096de DH |
201 | if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { |
202 | wait_queue_head_t *wq; | |
203 | ||
204 | signed long timeout = 60 * HZ; | |
205 | wait_queue_t wait; | |
206 | bool requeue; | |
207 | ||
208 | /* if the object we're waiting for is queued for processing, | |
209 | * then just put ourselves on the queue behind it */ | |
8b8edefa | 210 | if (work_pending(&xobject->fscache.work)) { |
fee096de DH |
211 | _debug("queue OBJ%x behind OBJ%x immediately", |
212 | object->fscache.debug_id, | |
213 | xobject->fscache.debug_id); | |
214 | goto requeue; | |
215 | } | |
216 | ||
217 | /* otherwise we sleep until either the object we're waiting for | |
8b8edefa | 218 | * is done, or the fscache_object is congested */ |
fee096de DH |
219 | wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE); |
220 | init_wait(&wait); | |
221 | requeue = false; | |
222 | do { | |
223 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
224 | if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) | |
225 | break; | |
8b8edefa TH |
226 | |
227 | requeue = fscache_object_sleep_till_congested(&timeout); | |
fee096de DH |
228 | } while (timeout > 0 && !requeue); |
229 | finish_wait(wq, &wait); | |
230 | ||
231 | if (requeue && | |
232 | test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) { | |
233 | _debug("queue OBJ%x behind OBJ%x after wait", | |
234 | object->fscache.debug_id, | |
235 | xobject->fscache.debug_id); | |
236 | goto requeue; | |
237 | } | |
238 | ||
239 | if (timeout <= 0) { | |
4e1eb883 | 240 | pr_err("\n"); |
0227d6ab | 241 | pr_err("Error: Overlong wait for old active object to go away\n"); |
fee096de DH |
242 | cachefiles_printk_object(object, xobject); |
243 | goto requeue; | |
244 | } | |
245 | } | |
246 | ||
247 | ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)); | |
9ae326a6 DH |
248 | |
249 | cache->cache.ops->put_object(&xobject->fscache); | |
250 | goto try_again; | |
fee096de DH |
251 | |
252 | requeue: | |
253 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
254 | cache->cache.ops->put_object(&xobject->fscache); | |
255 | _leave(" = -ETIMEDOUT"); | |
256 | return -ETIMEDOUT; | |
9ae326a6 DH |
257 | } |
258 | ||
259 | /* | |
260 | * delete an object representation from the cache | |
261 | * - file backed objects are unlinked | |
262 | * - directory backed objects are stuffed into the graveyard for userspace to | |
263 | * delete | |
264 | * - unlocks the directory mutex | |
265 | */ | |
266 | static int cachefiles_bury_object(struct cachefiles_cache *cache, | |
267 | struct dentry *dir, | |
c61ea31d DH |
268 | struct dentry *rep, |
269 | bool preemptive) | |
9ae326a6 DH |
270 | { |
271 | struct dentry *grave, *trap; | |
82140443 | 272 | struct path path, path_to_graveyard; |
9ae326a6 DH |
273 | char nbuffer[8 + 8 + 1]; |
274 | int ret; | |
275 | ||
276 | _enter(",'%*.*s','%*.*s'", | |
277 | dir->d_name.len, dir->d_name.len, dir->d_name.name, | |
278 | rep->d_name.len, rep->d_name.len, rep->d_name.name); | |
279 | ||
c61ea31d DH |
280 | _debug("remove %p from %p", rep, dir); |
281 | ||
9ae326a6 DH |
282 | /* non-directories can just be unlinked */ |
283 | if (!S_ISDIR(rep->d_inode->i_mode)) { | |
284 | _debug("unlink stale object"); | |
9ae326a6 | 285 | |
82140443 DH |
286 | path.mnt = cache->mnt; |
287 | path.dentry = dir; | |
288 | ret = security_path_unlink(&path, rep); | |
289 | if (ret < 0) { | |
290 | cachefiles_io_error(cache, "Unlink security error"); | |
291 | } else { | |
b21996e3 | 292 | ret = vfs_unlink(dir->d_inode, rep, NULL); |
82140443 DH |
293 | |
294 | if (preemptive) | |
295 | cachefiles_mark_object_buried(cache, rep); | |
296 | } | |
c61ea31d | 297 | |
9ae326a6 DH |
298 | mutex_unlock(&dir->d_inode->i_mutex); |
299 | ||
300 | if (ret == -EIO) | |
301 | cachefiles_io_error(cache, "Unlink failed"); | |
302 | ||
303 | _leave(" = %d", ret); | |
304 | return ret; | |
305 | } | |
306 | ||
307 | /* directories have to be moved to the graveyard */ | |
308 | _debug("move stale object to graveyard"); | |
309 | mutex_unlock(&dir->d_inode->i_mutex); | |
310 | ||
311 | try_again: | |
312 | /* first step is to make up a grave dentry in the graveyard */ | |
313 | sprintf(nbuffer, "%08x%08x", | |
314 | (uint32_t) get_seconds(), | |
315 | (uint32_t) atomic_inc_return(&cache->gravecounter)); | |
316 | ||
317 | /* do the multiway lock magic */ | |
318 | trap = lock_rename(cache->graveyard, dir); | |
319 | ||
320 | /* do some checks before getting the grave dentry */ | |
321 | if (rep->d_parent != dir) { | |
322 | /* the entry was probably culled when we dropped the parent dir | |
323 | * lock */ | |
324 | unlock_rename(cache->graveyard, dir); | |
325 | _leave(" = 0 [culled?]"); | |
326 | return 0; | |
327 | } | |
328 | ||
329 | if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) { | |
330 | unlock_rename(cache->graveyard, dir); | |
331 | cachefiles_io_error(cache, "Graveyard no longer a directory"); | |
332 | return -EIO; | |
333 | } | |
334 | ||
335 | if (trap == rep) { | |
336 | unlock_rename(cache->graveyard, dir); | |
337 | cachefiles_io_error(cache, "May not make directory loop"); | |
338 | return -EIO; | |
339 | } | |
340 | ||
341 | if (d_mountpoint(rep)) { | |
342 | unlock_rename(cache->graveyard, dir); | |
343 | cachefiles_io_error(cache, "Mountpoint in cache"); | |
344 | return -EIO; | |
345 | } | |
346 | ||
347 | grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer)); | |
348 | if (IS_ERR(grave)) { | |
349 | unlock_rename(cache->graveyard, dir); | |
350 | ||
351 | if (PTR_ERR(grave) == -ENOMEM) { | |
352 | _leave(" = -ENOMEM"); | |
353 | return -ENOMEM; | |
354 | } | |
355 | ||
356 | cachefiles_io_error(cache, "Lookup error %ld", | |
357 | PTR_ERR(grave)); | |
358 | return -EIO; | |
359 | } | |
360 | ||
361 | if (grave->d_inode) { | |
362 | unlock_rename(cache->graveyard, dir); | |
363 | dput(grave); | |
364 | grave = NULL; | |
365 | cond_resched(); | |
366 | goto try_again; | |
367 | } | |
368 | ||
369 | if (d_mountpoint(grave)) { | |
370 | unlock_rename(cache->graveyard, dir); | |
371 | dput(grave); | |
372 | cachefiles_io_error(cache, "Mountpoint in graveyard"); | |
373 | return -EIO; | |
374 | } | |
375 | ||
376 | /* target should not be an ancestor of source */ | |
377 | if (trap == grave) { | |
378 | unlock_rename(cache->graveyard, dir); | |
379 | dput(grave); | |
380 | cachefiles_io_error(cache, "May not make directory loop"); | |
381 | return -EIO; | |
382 | } | |
383 | ||
384 | /* attempt the rename */ | |
82140443 DH |
385 | path.mnt = cache->mnt; |
386 | path.dentry = dir; | |
387 | path_to_graveyard.mnt = cache->mnt; | |
388 | path_to_graveyard.dentry = cache->graveyard; | |
0b3974eb | 389 | ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0); |
82140443 DH |
390 | if (ret < 0) { |
391 | cachefiles_io_error(cache, "Rename security error %d", ret); | |
392 | } else { | |
393 | ret = vfs_rename(dir->d_inode, rep, | |
520c8b16 | 394 | cache->graveyard->d_inode, grave, NULL, 0); |
82140443 DH |
395 | if (ret != 0 && ret != -ENOMEM) |
396 | cachefiles_io_error(cache, | |
397 | "Rename failed with error %d", ret); | |
9ae326a6 | 398 | |
82140443 DH |
399 | if (preemptive) |
400 | cachefiles_mark_object_buried(cache, rep); | |
401 | } | |
c61ea31d | 402 | |
9ae326a6 DH |
403 | unlock_rename(cache->graveyard, dir); |
404 | dput(grave); | |
405 | _leave(" = 0"); | |
406 | return 0; | |
407 | } | |
408 | ||
409 | /* | |
410 | * delete an object representation from the cache | |
411 | */ | |
412 | int cachefiles_delete_object(struct cachefiles_cache *cache, | |
413 | struct cachefiles_object *object) | |
414 | { | |
415 | struct dentry *dir; | |
416 | int ret; | |
417 | ||
c61ea31d | 418 | _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry); |
9ae326a6 DH |
419 | |
420 | ASSERT(object->dentry); | |
421 | ASSERT(object->dentry->d_inode); | |
422 | ASSERT(object->dentry->d_parent); | |
423 | ||
424 | dir = dget_parent(object->dentry); | |
425 | ||
6511de33 | 426 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
8f9941ae | 427 | |
c61ea31d DH |
428 | if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) { |
429 | /* object allocation for the same key preemptively deleted this | |
430 | * object's file so that it could create its own file */ | |
431 | _debug("object preemptively buried"); | |
8f9941ae DH |
432 | mutex_unlock(&dir->d_inode->i_mutex); |
433 | ret = 0; | |
c61ea31d DH |
434 | } else { |
435 | /* we need to check that our parent is _still_ our parent - it | |
436 | * may have been renamed */ | |
437 | if (dir == object->dentry->d_parent) { | |
438 | ret = cachefiles_bury_object(cache, dir, | |
439 | object->dentry, false); | |
440 | } else { | |
441 | /* it got moved, presumably by cachefilesd culling it, | |
442 | * so it's no longer in the key path and we can ignore | |
443 | * it */ | |
444 | mutex_unlock(&dir->d_inode->i_mutex); | |
445 | ret = 0; | |
446 | } | |
8f9941ae | 447 | } |
9ae326a6 DH |
448 | |
449 | dput(dir); | |
450 | _leave(" = %d", ret); | |
451 | return ret; | |
452 | } | |
453 | ||
454 | /* | |
455 | * walk from the parent object to the child object through the backing | |
456 | * filesystem, creating directories as we go | |
457 | */ | |
458 | int cachefiles_walk_to_object(struct cachefiles_object *parent, | |
459 | struct cachefiles_object *object, | |
460 | const char *key, | |
461 | struct cachefiles_xattr *auxdata) | |
462 | { | |
463 | struct cachefiles_cache *cache; | |
464 | struct dentry *dir, *next = NULL; | |
82140443 | 465 | struct path path; |
9ae326a6 DH |
466 | unsigned long start; |
467 | const char *name; | |
468 | int ret, nlen; | |
469 | ||
c61ea31d DH |
470 | _enter("OBJ%x{%p},OBJ%x,%s,", |
471 | parent->fscache.debug_id, parent->dentry, | |
472 | object->fscache.debug_id, key); | |
9ae326a6 DH |
473 | |
474 | cache = container_of(parent->fscache.cache, | |
475 | struct cachefiles_cache, cache); | |
82140443 | 476 | path.mnt = cache->mnt; |
9ae326a6 DH |
477 | |
478 | ASSERT(parent->dentry); | |
479 | ASSERT(parent->dentry->d_inode); | |
480 | ||
481 | if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) { | |
482 | // TODO: convert file to dir | |
483 | _leave("looking up in none directory"); | |
484 | return -ENOBUFS; | |
485 | } | |
486 | ||
487 | dir = dget(parent->dentry); | |
488 | ||
489 | advance: | |
490 | /* attempt to transit the first directory component */ | |
491 | name = key; | |
492 | nlen = strlen(key); | |
493 | ||
494 | /* key ends in a double NUL */ | |
495 | key = key + nlen + 1; | |
496 | if (!*key) | |
497 | key = NULL; | |
498 | ||
499 | lookup_again: | |
500 | /* search the current directory for the element name */ | |
501 | _debug("lookup '%s'", name); | |
502 | ||
6511de33 | 503 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
504 | |
505 | start = jiffies; | |
506 | next = lookup_one_len(name, dir, nlen); | |
507 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
508 | if (IS_ERR(next)) | |
509 | goto lookup_error; | |
510 | ||
511 | _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative"); | |
512 | ||
513 | if (!key) | |
514 | object->new = !next->d_inode; | |
515 | ||
516 | /* if this element of the path doesn't exist, then the lookup phase | |
517 | * failed, and we can release any readers in the certain knowledge that | |
518 | * there's nothing for them to actually read */ | |
519 | if (!next->d_inode) | |
520 | fscache_object_lookup_negative(&object->fscache); | |
521 | ||
522 | /* we need to create the object if it's negative */ | |
523 | if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) { | |
524 | /* index objects and intervening tree levels must be subdirs */ | |
525 | if (!next->d_inode) { | |
526 | ret = cachefiles_has_space(cache, 1, 0); | |
527 | if (ret < 0) | |
528 | goto create_error; | |
529 | ||
82140443 DH |
530 | path.dentry = dir; |
531 | ret = security_path_mkdir(&path, next, 0); | |
532 | if (ret < 0) | |
533 | goto create_error; | |
9ae326a6 DH |
534 | start = jiffies; |
535 | ret = vfs_mkdir(dir->d_inode, next, 0); | |
536 | cachefiles_hist(cachefiles_mkdir_histogram, start); | |
537 | if (ret < 0) | |
538 | goto create_error; | |
539 | ||
540 | ASSERT(next->d_inode); | |
541 | ||
542 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
543 | next, next->d_inode, next->d_inode->i_ino); | |
544 | ||
545 | } else if (!S_ISDIR(next->d_inode->i_mode)) { | |
6ff66ac7 | 546 | pr_err("inode %lu is not a directory\n", |
9ae326a6 DH |
547 | next->d_inode->i_ino); |
548 | ret = -ENOBUFS; | |
549 | goto error; | |
550 | } | |
551 | ||
552 | } else { | |
553 | /* non-index objects start out life as files */ | |
554 | if (!next->d_inode) { | |
555 | ret = cachefiles_has_space(cache, 1, 0); | |
556 | if (ret < 0) | |
557 | goto create_error; | |
558 | ||
82140443 DH |
559 | path.dentry = dir; |
560 | ret = security_path_mknod(&path, next, S_IFREG, 0); | |
561 | if (ret < 0) | |
562 | goto create_error; | |
9ae326a6 | 563 | start = jiffies; |
312b63fb | 564 | ret = vfs_create(dir->d_inode, next, S_IFREG, true); |
9ae326a6 DH |
565 | cachefiles_hist(cachefiles_create_histogram, start); |
566 | if (ret < 0) | |
567 | goto create_error; | |
568 | ||
569 | ASSERT(next->d_inode); | |
570 | ||
571 | _debug("create -> %p{%p{ino=%lu}}", | |
572 | next, next->d_inode, next->d_inode->i_ino); | |
573 | ||
574 | } else if (!S_ISDIR(next->d_inode->i_mode) && | |
575 | !S_ISREG(next->d_inode->i_mode) | |
576 | ) { | |
6ff66ac7 | 577 | pr_err("inode %lu is not a file or directory\n", |
9ae326a6 DH |
578 | next->d_inode->i_ino); |
579 | ret = -ENOBUFS; | |
580 | goto error; | |
581 | } | |
582 | } | |
583 | ||
584 | /* process the next component */ | |
585 | if (key) { | |
586 | _debug("advance"); | |
587 | mutex_unlock(&dir->d_inode->i_mutex); | |
588 | dput(dir); | |
589 | dir = next; | |
590 | next = NULL; | |
591 | goto advance; | |
592 | } | |
593 | ||
594 | /* we've found the object we were looking for */ | |
595 | object->dentry = next; | |
596 | ||
597 | /* if we've found that the terminal object exists, then we need to | |
598 | * check its attributes and delete it if it's out of date */ | |
599 | if (!object->new) { | |
600 | _debug("validate '%*.*s'", | |
601 | next->d_name.len, next->d_name.len, next->d_name.name); | |
602 | ||
603 | ret = cachefiles_check_object_xattr(object, auxdata); | |
604 | if (ret == -ESTALE) { | |
605 | /* delete the object (the deleter drops the directory | |
606 | * mutex) */ | |
607 | object->dentry = NULL; | |
608 | ||
c61ea31d | 609 | ret = cachefiles_bury_object(cache, dir, next, true); |
9ae326a6 DH |
610 | dput(next); |
611 | next = NULL; | |
612 | ||
613 | if (ret < 0) | |
614 | goto delete_error; | |
615 | ||
616 | _debug("redo lookup"); | |
617 | goto lookup_again; | |
618 | } | |
619 | } | |
620 | ||
621 | /* note that we're now using this object */ | |
fee096de | 622 | ret = cachefiles_mark_object_active(cache, object); |
9ae326a6 DH |
623 | |
624 | mutex_unlock(&dir->d_inode->i_mutex); | |
625 | dput(dir); | |
626 | dir = NULL; | |
627 | ||
fee096de DH |
628 | if (ret == -ETIMEDOUT) |
629 | goto mark_active_timed_out; | |
630 | ||
9ae326a6 DH |
631 | _debug("=== OBTAINED_OBJECT ==="); |
632 | ||
633 | if (object->new) { | |
634 | /* attach data to a newly constructed terminal object */ | |
635 | ret = cachefiles_set_object_xattr(object, auxdata); | |
636 | if (ret < 0) | |
637 | goto check_error; | |
638 | } else { | |
639 | /* always update the atime on an object we've just looked up | |
640 | * (this is used to keep track of culling, and atimes are only | |
641 | * updated by read, write and readdir but not lookup or | |
642 | * open) */ | |
68ac1234 AV |
643 | path.dentry = next; |
644 | touch_atime(&path); | |
9ae326a6 DH |
645 | } |
646 | ||
647 | /* open a file interface onto a data file */ | |
648 | if (object->type != FSCACHE_COOKIE_TYPE_INDEX) { | |
649 | if (S_ISREG(object->dentry->d_inode->i_mode)) { | |
650 | const struct address_space_operations *aops; | |
651 | ||
652 | ret = -EPERM; | |
653 | aops = object->dentry->d_inode->i_mapping->a_ops; | |
654 | if (!aops->bmap) | |
655 | goto check_error; | |
656 | ||
657 | object->backer = object->dentry; | |
658 | } else { | |
659 | BUG(); // TODO: open file in data-class subdir | |
660 | } | |
661 | } | |
662 | ||
663 | object->new = 0; | |
664 | fscache_obtained_object(&object->fscache); | |
665 | ||
666 | _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino); | |
667 | return 0; | |
668 | ||
669 | create_error: | |
670 | _debug("create error %d", ret); | |
671 | if (ret == -EIO) | |
672 | cachefiles_io_error(cache, "Create/mkdir failed"); | |
673 | goto error; | |
674 | ||
fee096de DH |
675 | mark_active_timed_out: |
676 | _debug("mark active timed out"); | |
677 | goto release_dentry; | |
678 | ||
9ae326a6 DH |
679 | check_error: |
680 | _debug("check error %d", ret); | |
681 | write_lock(&cache->active_lock); | |
682 | rb_erase(&object->active_node, &cache->active_nodes); | |
683 | clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); | |
684 | wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); | |
685 | write_unlock(&cache->active_lock); | |
fee096de | 686 | release_dentry: |
9ae326a6 DH |
687 | dput(object->dentry); |
688 | object->dentry = NULL; | |
689 | goto error_out; | |
690 | ||
691 | delete_error: | |
692 | _debug("delete error %d", ret); | |
693 | goto error_out2; | |
694 | ||
695 | lookup_error: | |
696 | _debug("lookup error %ld", PTR_ERR(next)); | |
697 | ret = PTR_ERR(next); | |
698 | if (ret == -EIO) | |
699 | cachefiles_io_error(cache, "Lookup failed"); | |
700 | next = NULL; | |
701 | error: | |
702 | mutex_unlock(&dir->d_inode->i_mutex); | |
703 | dput(next); | |
704 | error_out2: | |
705 | dput(dir); | |
706 | error_out: | |
9ae326a6 DH |
707 | _leave(" = error %d", -ret); |
708 | return ret; | |
709 | } | |
710 | ||
711 | /* | |
712 | * get a subdirectory | |
713 | */ | |
714 | struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, | |
715 | struct dentry *dir, | |
716 | const char *dirname) | |
717 | { | |
718 | struct dentry *subdir; | |
719 | unsigned long start; | |
82140443 | 720 | struct path path; |
9ae326a6 DH |
721 | int ret; |
722 | ||
723 | _enter(",,%s", dirname); | |
724 | ||
725 | /* search the current directory for the element name */ | |
726 | mutex_lock(&dir->d_inode->i_mutex); | |
727 | ||
728 | start = jiffies; | |
729 | subdir = lookup_one_len(dirname, dir, strlen(dirname)); | |
730 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
731 | if (IS_ERR(subdir)) { | |
732 | if (PTR_ERR(subdir) == -ENOMEM) | |
733 | goto nomem_d_alloc; | |
734 | goto lookup_error; | |
735 | } | |
736 | ||
737 | _debug("subdir -> %p %s", | |
738 | subdir, subdir->d_inode ? "positive" : "negative"); | |
739 | ||
740 | /* we need to create the subdir if it doesn't exist yet */ | |
741 | if (!subdir->d_inode) { | |
742 | ret = cachefiles_has_space(cache, 1, 0); | |
743 | if (ret < 0) | |
744 | goto mkdir_error; | |
745 | ||
746 | _debug("attempt mkdir"); | |
747 | ||
82140443 DH |
748 | path.mnt = cache->mnt; |
749 | path.dentry = dir; | |
750 | ret = security_path_mkdir(&path, subdir, 0700); | |
751 | if (ret < 0) | |
752 | goto mkdir_error; | |
9ae326a6 DH |
753 | ret = vfs_mkdir(dir->d_inode, subdir, 0700); |
754 | if (ret < 0) | |
755 | goto mkdir_error; | |
756 | ||
757 | ASSERT(subdir->d_inode); | |
758 | ||
759 | _debug("mkdir -> %p{%p{ino=%lu}}", | |
760 | subdir, | |
761 | subdir->d_inode, | |
762 | subdir->d_inode->i_ino); | |
763 | } | |
764 | ||
765 | mutex_unlock(&dir->d_inode->i_mutex); | |
766 | ||
767 | /* we need to make sure the subdir is a directory */ | |
768 | ASSERT(subdir->d_inode); | |
769 | ||
770 | if (!S_ISDIR(subdir->d_inode->i_mode)) { | |
6ff66ac7 | 771 | pr_err("%s is not a directory\n", dirname); |
9ae326a6 DH |
772 | ret = -EIO; |
773 | goto check_error; | |
774 | } | |
775 | ||
776 | ret = -EPERM; | |
627bf81a | 777 | if (!subdir->d_inode->i_op->setxattr || |
9ae326a6 DH |
778 | !subdir->d_inode->i_op->getxattr || |
779 | !subdir->d_inode->i_op->lookup || | |
780 | !subdir->d_inode->i_op->mkdir || | |
781 | !subdir->d_inode->i_op->create || | |
e2cf1f1c DH |
782 | (!subdir->d_inode->i_op->rename && |
783 | !subdir->d_inode->i_op->rename2) || | |
9ae326a6 DH |
784 | !subdir->d_inode->i_op->rmdir || |
785 | !subdir->d_inode->i_op->unlink) | |
786 | goto check_error; | |
787 | ||
788 | _leave(" = [%lu]", subdir->d_inode->i_ino); | |
789 | return subdir; | |
790 | ||
791 | check_error: | |
792 | dput(subdir); | |
793 | _leave(" = %d [check]", ret); | |
794 | return ERR_PTR(ret); | |
795 | ||
796 | mkdir_error: | |
797 | mutex_unlock(&dir->d_inode->i_mutex); | |
798 | dput(subdir); | |
6ff66ac7 | 799 | pr_err("mkdir %s failed with error %d\n", dirname, ret); |
9ae326a6 DH |
800 | return ERR_PTR(ret); |
801 | ||
802 | lookup_error: | |
803 | mutex_unlock(&dir->d_inode->i_mutex); | |
804 | ret = PTR_ERR(subdir); | |
6ff66ac7 | 805 | pr_err("Lookup %s failed with error %d\n", dirname, ret); |
9ae326a6 DH |
806 | return ERR_PTR(ret); |
807 | ||
808 | nomem_d_alloc: | |
809 | mutex_unlock(&dir->d_inode->i_mutex); | |
810 | _leave(" = -ENOMEM"); | |
811 | return ERR_PTR(-ENOMEM); | |
812 | } | |
813 | ||
814 | /* | |
815 | * find out if an object is in use or not | |
816 | * - if finds object and it's not in use: | |
817 | * - returns a pointer to the object and a reference on it | |
818 | * - returns with the directory locked | |
819 | */ | |
820 | static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache, | |
821 | struct dentry *dir, | |
822 | char *filename) | |
823 | { | |
824 | struct cachefiles_object *object; | |
825 | struct rb_node *_n; | |
826 | struct dentry *victim; | |
827 | unsigned long start; | |
828 | int ret; | |
829 | ||
830 | //_enter(",%*.*s/,%s", | |
831 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
832 | ||
833 | /* look up the victim */ | |
6bd5e82b | 834 | mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); |
9ae326a6 DH |
835 | |
836 | start = jiffies; | |
837 | victim = lookup_one_len(filename, dir, strlen(filename)); | |
838 | cachefiles_hist(cachefiles_lookup_histogram, start); | |
839 | if (IS_ERR(victim)) | |
840 | goto lookup_error; | |
841 | ||
842 | //_debug("victim -> %p %s", | |
843 | // victim, victim->d_inode ? "positive" : "negative"); | |
844 | ||
845 | /* if the object is no longer there then we probably retired the object | |
846 | * at the netfs's request whilst the cull was in progress | |
847 | */ | |
848 | if (!victim->d_inode) { | |
849 | mutex_unlock(&dir->d_inode->i_mutex); | |
850 | dput(victim); | |
851 | _leave(" = -ENOENT [absent]"); | |
852 | return ERR_PTR(-ENOENT); | |
853 | } | |
854 | ||
855 | /* check to see if we're using this object */ | |
856 | read_lock(&cache->active_lock); | |
857 | ||
858 | _n = cache->active_nodes.rb_node; | |
859 | ||
860 | while (_n) { | |
861 | object = rb_entry(_n, struct cachefiles_object, active_node); | |
862 | ||
863 | if (object->dentry > victim) | |
864 | _n = _n->rb_left; | |
865 | else if (object->dentry < victim) | |
866 | _n = _n->rb_right; | |
867 | else | |
868 | goto object_in_use; | |
869 | } | |
870 | ||
871 | read_unlock(&cache->active_lock); | |
872 | ||
873 | //_leave(" = %p", victim); | |
874 | return victim; | |
875 | ||
876 | object_in_use: | |
877 | read_unlock(&cache->active_lock); | |
878 | mutex_unlock(&dir->d_inode->i_mutex); | |
879 | dput(victim); | |
880 | //_leave(" = -EBUSY [in use]"); | |
881 | return ERR_PTR(-EBUSY); | |
882 | ||
883 | lookup_error: | |
884 | mutex_unlock(&dir->d_inode->i_mutex); | |
885 | ret = PTR_ERR(victim); | |
886 | if (ret == -ENOENT) { | |
887 | /* file or dir now absent - probably retired by netfs */ | |
888 | _leave(" = -ESTALE [absent]"); | |
889 | return ERR_PTR(-ESTALE); | |
890 | } | |
891 | ||
892 | if (ret == -EIO) { | |
893 | cachefiles_io_error(cache, "Lookup failed"); | |
894 | } else if (ret != -ENOMEM) { | |
6ff66ac7 | 895 | pr_err("Internal error: %d\n", ret); |
9ae326a6 DH |
896 | ret = -EIO; |
897 | } | |
898 | ||
899 | _leave(" = %d", ret); | |
900 | return ERR_PTR(ret); | |
901 | } | |
902 | ||
903 | /* | |
904 | * cull an object if it's not in use | |
905 | * - called only by cache manager daemon | |
906 | */ | |
907 | int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir, | |
908 | char *filename) | |
909 | { | |
910 | struct dentry *victim; | |
911 | int ret; | |
912 | ||
913 | _enter(",%*.*s/,%s", | |
914 | dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
915 | ||
916 | victim = cachefiles_check_active(cache, dir, filename); | |
917 | if (IS_ERR(victim)) | |
918 | return PTR_ERR(victim); | |
919 | ||
920 | _debug("victim -> %p %s", | |
921 | victim, victim->d_inode ? "positive" : "negative"); | |
922 | ||
923 | /* okay... the victim is not being used so we can cull it | |
924 | * - start by marking it as stale | |
925 | */ | |
926 | _debug("victim is cullable"); | |
927 | ||
928 | ret = cachefiles_remove_object_xattr(cache, victim); | |
929 | if (ret < 0) | |
930 | goto error_unlock; | |
931 | ||
932 | /* actually remove the victim (drops the dir mutex) */ | |
933 | _debug("bury"); | |
934 | ||
c61ea31d | 935 | ret = cachefiles_bury_object(cache, dir, victim, false); |
9ae326a6 DH |
936 | if (ret < 0) |
937 | goto error; | |
938 | ||
939 | dput(victim); | |
940 | _leave(" = 0"); | |
941 | return 0; | |
942 | ||
943 | error_unlock: | |
944 | mutex_unlock(&dir->d_inode->i_mutex); | |
945 | error: | |
946 | dput(victim); | |
947 | if (ret == -ENOENT) { | |
948 | /* file or dir now absent - probably retired by netfs */ | |
949 | _leave(" = -ESTALE [absent]"); | |
950 | return -ESTALE; | |
951 | } | |
952 | ||
953 | if (ret != -ENOMEM) { | |
6ff66ac7 | 954 | pr_err("Internal error: %d\n", ret); |
9ae326a6 DH |
955 | ret = -EIO; |
956 | } | |
957 | ||
958 | _leave(" = %d", ret); | |
959 | return ret; | |
960 | } | |
961 | ||
962 | /* | |
963 | * find out if an object is in use or not | |
964 | * - called only by cache manager daemon | |
965 | * - returns -EBUSY or 0 to indicate whether an object is in use or not | |
966 | */ | |
967 | int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir, | |
968 | char *filename) | |
969 | { | |
970 | struct dentry *victim; | |
971 | ||
972 | //_enter(",%*.*s/,%s", | |
973 | // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename); | |
974 | ||
975 | victim = cachefiles_check_active(cache, dir, filename); | |
976 | if (IS_ERR(victim)) | |
977 | return PTR_ERR(victim); | |
978 | ||
979 | mutex_unlock(&dir->d_inode->i_mutex); | |
980 | dput(victim); | |
981 | //_leave(" = 0"); | |
982 | return 0; | |
983 | } |