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drivers: power: report battery voltage in AOSP compatible format
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / cachefiles / namei.c
CommitLineData
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 */
30static noinline
31void __cachefiles_printk_object(struct cachefiles_object *object,
32 const char *prefix,
33 u8 *keybuf)
34{
35 struct fscache_cookie *cookie;
36 unsigned keylen, loop;
37
38 printk(KERN_ERR "%sobject: OBJ%x\n",
39 prefix, object->fscache.debug_id);
8b8edefa 40 printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
d0e27b78 41 prefix, fscache_object_states[object->fscache.state],
8b8edefa 42 object->fscache.flags, work_busy(&object->fscache.work),
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);
59 if (keybuf)
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 */
81static 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 */
100static 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 */
127found_dentry:
128 kdebug("preemptive burial: OBJ%x [%s] %p",
129 object->fscache.debug_id,
130 fscache_object_states[object->fscache.state],
131 dentry);
132
133 if (object->fscache.state < FSCACHE_OBJECT_DYING) {
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		 150static 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
159try_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 */
194wait_for_old_object:
195 if (xobject->fscache.state < FSCACHE_OBJECT_DYING) {
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
257requeue:
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 */
271static 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 {
297 ret = vfs_unlink(dir->d_inode, rep);
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
316try_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;
394 ret = security_path_rename(&path, rep, &path_to_graveyard, grave);
395 if (ret < 0) {
396 cachefiles_io_error(cache, "Rename security error %d", ret);
397 } else {
398 ret = vfs_rename(dir->d_inode, rep,
399 cache->graveyard->d_inode, grave);
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 */
417int 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 */
463int 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
494advance:
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
504lookup_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
674create_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		 680mark_active_timed_out:
681 _debug("mark active timed out");
682 goto release_dentry;
683
9ae326a6
DH		 684check_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 691release_dentry:
9ae326a6
DH		 692 dput(object->dentry);
693 object->dentry = NULL;
694 goto error_out;
695
696delete_error:
697 _debug("delete error %d", ret);
698 goto error_out2;
699
700lookup_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;
706error:
707 mutex_unlock(&dir->d_inode->i_mutex);
708 dput(next);
709error_out2:
710 dput(dir);
711error_out:
9ae326a6
DH		 712 _leave(" = error %d", -ret);
713 return ret;
714}
715
716/*
717 * get a subdirectory
718 */
719struct 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;
782 if (!subdir->d_inode->i_op ||
783 !subdir->d_inode->i_op->setxattr ||
784 !subdir->d_inode->i_op->getxattr ||
785 !subdir->d_inode->i_op->lookup ||
786 !subdir->d_inode->i_op->mkdir ||
787 !subdir->d_inode->i_op->create ||
788 !subdir->d_inode->i_op->rename ||
789 !subdir->d_inode->i_op->rmdir ||
790 !subdir->d_inode->i_op->unlink)
791 goto check_error;
792
793 _leave(" = [%lu]", subdir->d_inode->i_ino);
794 return subdir;
795
796check_error:
797 dput(subdir);
798 _leave(" = %d [check]", ret);
799 return ERR_PTR(ret);
800
801mkdir_error:
802 mutex_unlock(&dir->d_inode->i_mutex);
803 dput(subdir);
804 kerror("mkdir %s failed with error %d", dirname, ret);
805 return ERR_PTR(ret);
806
807lookup_error:
808 mutex_unlock(&dir->d_inode->i_mutex);
809 ret = PTR_ERR(subdir);
810 kerror("Lookup %s failed with error %d", dirname, ret);
811 return ERR_PTR(ret);
812
813nomem_d_alloc:
814 mutex_unlock(&dir->d_inode->i_mutex);
815 _leave(" = -ENOMEM");
816 return ERR_PTR(-ENOMEM);
817}
818
819/*
820 * find out if an object is in use or not
821 * - if finds object and it's not in use:
822 * - returns a pointer to the object and a reference on it
823 * - returns with the directory locked
824 */
825static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
826 struct dentry *dir,
827 char *filename)
828{
829 struct cachefiles_object *object;
830 struct rb_node *_n;
831 struct dentry *victim;
832 unsigned long start;
833 int ret;
834
835 //_enter(",%*.*s/,%s",
836 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
837
838 /* look up the victim */
839 mutex_lock_nested(&dir->d_inode->i_mutex, 1);
840
841 start = jiffies;
842 victim = lookup_one_len(filename, dir, strlen(filename));
843 cachefiles_hist(cachefiles_lookup_histogram, start);
844 if (IS_ERR(victim))
845 goto lookup_error;
846
847 //_debug("victim -> %p %s",
848 // victim, victim->d_inode ? "positive" : "negative");
849
850 /* if the object is no longer there then we probably retired the object
851 * at the netfs's request whilst the cull was in progress
852 */
853 if (!victim->d_inode) {
854 mutex_unlock(&dir->d_inode->i_mutex);
855 dput(victim);
856 _leave(" = -ENOENT [absent]");
857 return ERR_PTR(-ENOENT);
858 }
859
860 /* check to see if we're using this object */
861 read_lock(&cache->active_lock);
862
863 _n = cache->active_nodes.rb_node;
864
865 while (_n) {
866 object = rb_entry(_n, struct cachefiles_object, active_node);
867
868 if (object->dentry > victim)
869 _n = _n->rb_left;
870 else if (object->dentry < victim)
871 _n = _n->rb_right;
872 else
873 goto object_in_use;
874 }
875
876 read_unlock(&cache->active_lock);
877
878 //_leave(" = %p", victim);
879 return victim;
880
881object_in_use:
882 read_unlock(&cache->active_lock);
883 mutex_unlock(&dir->d_inode->i_mutex);
884 dput(victim);
885 //_leave(" = -EBUSY [in use]");
886 return ERR_PTR(-EBUSY);
887
888lookup_error:
889 mutex_unlock(&dir->d_inode->i_mutex);
890 ret = PTR_ERR(victim);
891 if (ret == -ENOENT) {
892 /* file or dir now absent - probably retired by netfs */
893 _leave(" = -ESTALE [absent]");
894 return ERR_PTR(-ESTALE);
895 }
896
897 if (ret == -EIO) {
898 cachefiles_io_error(cache, "Lookup failed");
899 } else if (ret != -ENOMEM) {
900 kerror("Internal error: %d", ret);
901 ret = -EIO;
902 }
903
904 _leave(" = %d", ret);
905 return ERR_PTR(ret);
906}
907
908/*
909 * cull an object if it's not in use
910 * - called only by cache manager daemon
911 */
912int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
913 char *filename)
914{
915 struct dentry *victim;
916 int ret;
917
918 _enter(",%*.*s/,%s",
919 dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
920
921 victim = cachefiles_check_active(cache, dir, filename);
922 if (IS_ERR(victim))
923 return PTR_ERR(victim);
924
925 _debug("victim -> %p %s",
926 victim, victim->d_inode ? "positive" : "negative");
927
928 /* okay... the victim is not being used so we can cull it
929 * - start by marking it as stale
930 */
931 _debug("victim is cullable");
932
933 ret = cachefiles_remove_object_xattr(cache, victim);
934 if (ret < 0)
935 goto error_unlock;
936
937 /* actually remove the victim (drops the dir mutex) */
938 _debug("bury");
939
c61ea31d 940 ret = cachefiles_bury_object(cache, dir, victim, false);
9ae326a6
DH		 941 if (ret < 0)
942 goto error;
943
944 dput(victim);
945 _leave(" = 0");
946 return 0;
947
948error_unlock:
949 mutex_unlock(&dir->d_inode->i_mutex);
950error:
951 dput(victim);
952 if (ret == -ENOENT) {
953 /* file or dir now absent - probably retired by netfs */
954 _leave(" = -ESTALE [absent]");
955 return -ESTALE;
956 }
957
958 if (ret != -ENOMEM) {
959 kerror("Internal error: %d", ret);
960 ret = -EIO;
961 }
962
963 _leave(" = %d", ret);
964 return ret;
965}
966
967/*
968 * find out if an object is in use or not
969 * - called only by cache manager daemon
970 * - returns -EBUSY or 0 to indicate whether an object is in use or not
971 */
972int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
973 char *filename)
974{
975 struct dentry *victim;
976
977 //_enter(",%*.*s/,%s",
978 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
979
980 victim = cachefiles_check_active(cache, dir, filename);
981 if (IS_ERR(victim))
982 return PTR_ERR(victim);
983
984 mutex_unlock(&dir->d_inode->i_mutex);
985 dput(victim);
986 //_leave(" = 0");
987 return 0;
988}
kernel source for telekom puls (alcatel/mediatek)