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FS-Cache: Initialise the object event mask with the calculated mask
[deliverable/linux.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),
d0e27b78
DH		 43 object->fscache.events,
44 object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
45 printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
46 prefix, object->fscache.n_ops, object->fscache.n_in_progress,
47 object->fscache.n_exclusive);
48 printk(KERN_ERR "%sparent=%p\n",
49 prefix, object->fscache.parent);
50
51 spin_lock(&object->fscache.lock);
52 cookie = object->fscache.cookie;
53 if (cookie) {
54 printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n",
55 prefix,
56 object->fscache.cookie,
57 object->fscache.cookie->parent,
58 object->fscache.cookie->netfs_data,
59 object->fscache.cookie->flags);
60 if (keybuf)
61 keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
62 CACHEFILES_KEYBUF_SIZE);
63 else
64 keylen = 0;
65 } else {
66 printk(KERN_ERR "%scookie=NULL\n", prefix);
67 keylen = 0;
68 }
69 spin_unlock(&object->fscache.lock);
70
71 if (keylen) {
72 printk(KERN_ERR "%skey=[%u] '", prefix, keylen);
73 for (loop = 0; loop < keylen; loop++)
74 printk("%02x", keybuf[loop]);
75 printk("'\n");
76 }
77}
78
79/*
80 * dump debugging info about a pair of objects
81 */
82static noinline void cachefiles_printk_object(struct cachefiles_object *object,
83 struct cachefiles_object *xobject)
84{
85 u8 *keybuf;
86
87 keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO);
88 if (object)
89 __cachefiles_printk_object(object, "", keybuf);
90 if (xobject)
91 __cachefiles_printk_object(xobject, "x", keybuf);
92 kfree(keybuf);
93}
94
c61ea31d
DH		 95/*
96 * mark the owner of a dentry, if there is one, to indicate that that dentry
97 * has been preemptively deleted
98 * - the caller must hold the i_mutex on the dentry's parent as required to
99 * call vfs_unlink(), vfs_rmdir() or vfs_rename()
100 */
101static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
102 struct dentry *dentry)
103{
104 struct cachefiles_object *object;
105 struct rb_node *p;
106
107 _enter(",'%*.*s'",
108 dentry->d_name.len, dentry->d_name.len, dentry->d_name.name);
109
110 write_lock(&cache->active_lock);
111
112 p = cache->active_nodes.rb_node;
113 while (p) {
114 object = rb_entry(p, struct cachefiles_object, active_node);
115 if (object->dentry > dentry)
116 p = p->rb_left;
117 else if (object->dentry < dentry)
118 p = p->rb_right;
119 else
120 goto found_dentry;
121 }
122
123 write_unlock(&cache->active_lock);
124 _leave(" [no owner]");
125 return;
126
127 /* found the dentry for */
128found_dentry:
129 kdebug("preemptive burial: OBJ%x [%s] %p",
130 object->fscache.debug_id,
131 fscache_object_states[object->fscache.state],
132 dentry);
133
134 if (object->fscache.state < FSCACHE_OBJECT_DYING) {
135 printk(KERN_ERR "\n");
136 printk(KERN_ERR "CacheFiles: Error:"
137 " Can't preemptively bury live object\n");
138 cachefiles_printk_object(object, NULL);
139 } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
140 printk(KERN_ERR "CacheFiles: Error:"
141 " Object already preemptively buried\n");
142 }
143
144 write_unlock(&cache->active_lock);
145 _leave(" [owner marked]");
146}
147
9ae326a6
DH		 148/*
149 * record the fact that an object is now active
150 */
fee096de
DH		 151static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
152 struct cachefiles_object *object)
9ae326a6
DH		 153{
154 struct cachefiles_object *xobject;
155 struct rb_node **_p, *_parent = NULL;
156 struct dentry *dentry;
157
158 _enter(",%p", object);
159
160try_again:
161 write_lock(&cache->active_lock);
162
d0e27b78
DH		 163 if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
164 printk(KERN_ERR "CacheFiles: Error: Object already active\n");
165 cachefiles_printk_object(object, NULL);
9ae326a6 166 BUG();
d0e27b78 167 }
9ae326a6
DH		 168
169 dentry = object->dentry;
170 _p = &cache->active_nodes.rb_node;
171 while (*_p) {
172 _parent = *_p;
173 xobject = rb_entry(_parent,
174 struct cachefiles_object, active_node);
175
176 ASSERT(xobject != object);
177
178 if (xobject->dentry > dentry)
179 _p = &(*_p)->rb_left;
180 else if (xobject->dentry < dentry)
181 _p = &(*_p)->rb_right;
182 else
183 goto wait_for_old_object;
184 }
185
186 rb_link_node(&object->active_node, _parent, _p);
187 rb_insert_color(&object->active_node, &cache->active_nodes);
188
189 write_unlock(&cache->active_lock);
fee096de
DH		 190 _leave(" = 0");
191 return 0;
9ae326a6
DH		 192
193 /* an old object from a previous incarnation is hogging the slot - we
194 * need to wait for it to be destroyed */
195wait_for_old_object:
196 if (xobject->fscache.state < FSCACHE_OBJECT_DYING) {
197 printk(KERN_ERR "\n");
198 printk(KERN_ERR "CacheFiles: Error:"
199 " Unexpected object collision\n");
d0e27b78 200 cachefiles_printk_object(object, xobject);
9ae326a6
DH		 201 BUG();
202 }
203 atomic_inc(&xobject->usage);
204 write_unlock(&cache->active_lock);
205
fee096de
DH		 206 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
207 wait_queue_head_t *wq;
208
209 signed long timeout = 60 * HZ;
210 wait_queue_t wait;
211 bool requeue;
212
213 /* if the object we're waiting for is queued for processing,
214 * then just put ourselves on the queue behind it */
8b8edefa 215 if (work_pending(&xobject->fscache.work)) {
fee096de
DH		 216 _debug("queue OBJ%x behind OBJ%x immediately",
217 object->fscache.debug_id,
218 xobject->fscache.debug_id);
219 goto requeue;
220 }
221
222 /* otherwise we sleep until either the object we're waiting for
8b8edefa 223 * is done, or the fscache_object is congested */
fee096de
DH		 224 wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
225 init_wait(&wait);
226 requeue = false;
227 do {
228 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
229 if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
230 break;
8b8edefa
TH		 231
232 requeue = fscache_object_sleep_till_congested(&timeout);
fee096de
DH		 233 } while (timeout > 0 && !requeue);
234 finish_wait(wq, &wait);
235
236 if (requeue &&
237 test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
238 _debug("queue OBJ%x behind OBJ%x after wait",
239 object->fscache.debug_id,
240 xobject->fscache.debug_id);
241 goto requeue;
242 }
243
244 if (timeout <= 0) {
245 printk(KERN_ERR "\n");
246 printk(KERN_ERR "CacheFiles: Error: Overlong"
247 " wait for old active object to go away\n");
248 cachefiles_printk_object(object, xobject);
249 goto requeue;
250 }
251 }
252
253 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags));
9ae326a6
DH		 254
255 cache->cache.ops->put_object(&xobject->fscache);
256 goto try_again;
fee096de
DH		 257
258requeue:
259 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
260 cache->cache.ops->put_object(&xobject->fscache);
261 _leave(" = -ETIMEDOUT");
262 return -ETIMEDOUT;
9ae326a6
DH		 263}
264
265/*
266 * delete an object representation from the cache
267 * - file backed objects are unlinked
268 * - directory backed objects are stuffed into the graveyard for userspace to
269 * delete
270 * - unlocks the directory mutex
271 */
272static int cachefiles_bury_object(struct cachefiles_cache *cache,
273 struct dentry *dir,
c61ea31d
DH		 274 struct dentry *rep,
275 bool preemptive)
9ae326a6
DH		 276{
277 struct dentry *grave, *trap;
82140443 278 struct path path, path_to_graveyard;
9ae326a6
DH		 279 char nbuffer[8 + 8 + 1];
280 int ret;
281
282 _enter(",'%*.*s','%*.*s'",
283 dir->d_name.len, dir->d_name.len, dir->d_name.name,
284 rep->d_name.len, rep->d_name.len, rep->d_name.name);
285
c61ea31d
DH		 286 _debug("remove %p from %p", rep, dir);
287
9ae326a6
DH		 288 /* non-directories can just be unlinked */
289 if (!S_ISDIR(rep->d_inode->i_mode)) {
290 _debug("unlink stale object");
9ae326a6 291
82140443
DH		 292 path.mnt = cache->mnt;
293 path.dentry = dir;
294 ret = security_path_unlink(&path, rep);
295 if (ret < 0) {
296 cachefiles_io_error(cache, "Unlink security error");
297 } else {
298 ret = vfs_unlink(dir->d_inode, rep);
299
300 if (preemptive)
301 cachefiles_mark_object_buried(cache, rep);
302 }
c61ea31d 303
9ae326a6
DH		 304 mutex_unlock(&dir->d_inode->i_mutex);
305
306 if (ret == -EIO)
307 cachefiles_io_error(cache, "Unlink failed");
308
309 _leave(" = %d", ret);
310 return ret;
311 }
312
313 /* directories have to be moved to the graveyard */
314 _debug("move stale object to graveyard");
315 mutex_unlock(&dir->d_inode->i_mutex);
316
317try_again:
318 /* first step is to make up a grave dentry in the graveyard */
319 sprintf(nbuffer, "%08x%08x",
320 (uint32_t) get_seconds(),
321 (uint32_t) atomic_inc_return(&cache->gravecounter));
322
323 /* do the multiway lock magic */
324 trap = lock_rename(cache->graveyard, dir);
325
326 /* do some checks before getting the grave dentry */
327 if (rep->d_parent != dir) {
328 /* the entry was probably culled when we dropped the parent dir
329 * lock */
330 unlock_rename(cache->graveyard, dir);
331 _leave(" = 0 [culled?]");
332 return 0;
333 }
334
335 if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) {
336 unlock_rename(cache->graveyard, dir);
337 cachefiles_io_error(cache, "Graveyard no longer a directory");
338 return -EIO;
339 }
340
341 if (trap == rep) {
342 unlock_rename(cache->graveyard, dir);
343 cachefiles_io_error(cache, "May not make directory loop");
344 return -EIO;
345 }
346
347 if (d_mountpoint(rep)) {
348 unlock_rename(cache->graveyard, dir);
349 cachefiles_io_error(cache, "Mountpoint in cache");
350 return -EIO;
351 }
352
353 grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
354 if (IS_ERR(grave)) {
355 unlock_rename(cache->graveyard, dir);
356
357 if (PTR_ERR(grave) == -ENOMEM) {
358 _leave(" = -ENOMEM");
359 return -ENOMEM;
360 }
361
362 cachefiles_io_error(cache, "Lookup error %ld",
363 PTR_ERR(grave));
364 return -EIO;
365 }
366
367 if (grave->d_inode) {
368 unlock_rename(cache->graveyard, dir);
369 dput(grave);
370 grave = NULL;
371 cond_resched();
372 goto try_again;
373 }
374
375 if (d_mountpoint(grave)) {
376 unlock_rename(cache->graveyard, dir);
377 dput(grave);
378 cachefiles_io_error(cache, "Mountpoint in graveyard");
379 return -EIO;
380 }
381
382 /* target should not be an ancestor of source */
383 if (trap == grave) {
384 unlock_rename(cache->graveyard, dir);
385 dput(grave);
386 cachefiles_io_error(cache, "May not make directory loop");
387 return -EIO;
388 }
389
390 /* attempt the rename */
82140443
DH		 391 path.mnt = cache->mnt;
392 path.dentry = dir;
393 path_to_graveyard.mnt = cache->mnt;
394 path_to_graveyard.dentry = cache->graveyard;
395 ret = security_path_rename(&path, rep, &path_to_graveyard, grave);
396 if (ret < 0) {
397 cachefiles_io_error(cache, "Rename security error %d", ret);
398 } else {
399 ret = vfs_rename(dir->d_inode, rep,
400 cache->graveyard->d_inode, grave);
401 if (ret != 0 && ret != -ENOMEM)
402 cachefiles_io_error(cache,
403 "Rename failed with error %d", ret);
9ae326a6 404
82140443
DH		 405 if (preemptive)
406 cachefiles_mark_object_buried(cache, rep);
407 }
c61ea31d 408
9ae326a6
DH		 409 unlock_rename(cache->graveyard, dir);
410 dput(grave);
411 _leave(" = 0");
412 return 0;
413}
414
415/*
416 * delete an object representation from the cache
417 */
418int cachefiles_delete_object(struct cachefiles_cache *cache,
419 struct cachefiles_object *object)
420{
421 struct dentry *dir;
422 int ret;
423
c61ea31d 424 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
9ae326a6
DH		 425
426 ASSERT(object->dentry);
427 ASSERT(object->dentry->d_inode);
428 ASSERT(object->dentry->d_parent);
429
430 dir = dget_parent(object->dentry);
431
6511de33 432 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
8f9941ae 433
c61ea31d
DH		 434 if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
435 /* object allocation for the same key preemptively deleted this
436 * object's file so that it could create its own file */
437 _debug("object preemptively buried");
8f9941ae
DH		 438 mutex_unlock(&dir->d_inode->i_mutex);
439 ret = 0;
c61ea31d
DH		 440 } else {
441 /* we need to check that our parent is _still_ our parent - it
442 * may have been renamed */
443 if (dir == object->dentry->d_parent) {
444 ret = cachefiles_bury_object(cache, dir,
445 object->dentry, false);
446 } else {
447 /* it got moved, presumably by cachefilesd culling it,
448 * so it's no longer in the key path and we can ignore
449 * it */
450 mutex_unlock(&dir->d_inode->i_mutex);
451 ret = 0;
452 }
8f9941ae 453 }
9ae326a6
DH		 454
455 dput(dir);
456 _leave(" = %d", ret);
457 return ret;
458}
459
460/*
461 * walk from the parent object to the child object through the backing
462 * filesystem, creating directories as we go
463 */
464int cachefiles_walk_to_object(struct cachefiles_object *parent,
465 struct cachefiles_object *object,
466 const char *key,
467 struct cachefiles_xattr *auxdata)
468{
469 struct cachefiles_cache *cache;
470 struct dentry *dir, *next = NULL;
82140443 471 struct path path;
9ae326a6
DH		 472 unsigned long start;
473 const char *name;
474 int ret, nlen;
475
c61ea31d
DH		 476 _enter("OBJ%x{%p},OBJ%x,%s,",
477 parent->fscache.debug_id, parent->dentry,
478 object->fscache.debug_id, key);
9ae326a6
DH		 479
480 cache = container_of(parent->fscache.cache,
481 struct cachefiles_cache, cache);
82140443 482 path.mnt = cache->mnt;
9ae326a6
DH		 483
484 ASSERT(parent->dentry);
485 ASSERT(parent->dentry->d_inode);
486
487 if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) {
488 // TODO: convert file to dir
489 _leave("looking up in none directory");
490 return -ENOBUFS;
491 }
492
493 dir = dget(parent->dentry);
494
495advance:
496 /* attempt to transit the first directory component */
497 name = key;
498 nlen = strlen(key);
499
500 /* key ends in a double NUL */
501 key = key + nlen + 1;
502 if (!*key)
503 key = NULL;
504
505lookup_again:
506 /* search the current directory for the element name */
507 _debug("lookup '%s'", name);
508
6511de33 509 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
9ae326a6
DH		 510
511 start = jiffies;
512 next = lookup_one_len(name, dir, nlen);
513 cachefiles_hist(cachefiles_lookup_histogram, start);
514 if (IS_ERR(next))
515 goto lookup_error;
516
517 _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative");
518
519 if (!key)
520 object->new = !next->d_inode;
521
522 /* if this element of the path doesn't exist, then the lookup phase
523 * failed, and we can release any readers in the certain knowledge that
524 * there's nothing for them to actually read */
525 if (!next->d_inode)
526 fscache_object_lookup_negative(&object->fscache);
527
528 /* we need to create the object if it's negative */
529 if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) {
530 /* index objects and intervening tree levels must be subdirs */
531 if (!next->d_inode) {
532 ret = cachefiles_has_space(cache, 1, 0);
533 if (ret < 0)
534 goto create_error;
535
82140443
DH		 536 path.dentry = dir;
537 ret = security_path_mkdir(&path, next, 0);
538 if (ret < 0)
539 goto create_error;
9ae326a6
DH		 540 start = jiffies;
541 ret = vfs_mkdir(dir->d_inode, next, 0);
542 cachefiles_hist(cachefiles_mkdir_histogram, start);
543 if (ret < 0)
544 goto create_error;
545
546 ASSERT(next->d_inode);
547
548 _debug("mkdir -> %p{%p{ino=%lu}}",
549 next, next->d_inode, next->d_inode->i_ino);
550
551 } else if (!S_ISDIR(next->d_inode->i_mode)) {
552 kerror("inode %lu is not a directory",
553 next->d_inode->i_ino);
554 ret = -ENOBUFS;
555 goto error;
556 }
557
558 } else {
559 /* non-index objects start out life as files */
560 if (!next->d_inode) {
561 ret = cachefiles_has_space(cache, 1, 0);
562 if (ret < 0)
563 goto create_error;
564
82140443
DH		 565 path.dentry = dir;
566 ret = security_path_mknod(&path, next, S_IFREG, 0);
567 if (ret < 0)
568 goto create_error;
9ae326a6 569 start = jiffies;
312b63fb 570 ret = vfs_create(dir->d_inode, next, S_IFREG, true);
9ae326a6
DH		 571 cachefiles_hist(cachefiles_create_histogram, start);
572 if (ret < 0)
573 goto create_error;
574
575 ASSERT(next->d_inode);
576
577 _debug("create -> %p{%p{ino=%lu}}",
578 next, next->d_inode, next->d_inode->i_ino);
579
580 } else if (!S_ISDIR(next->d_inode->i_mode) &&
581 !S_ISREG(next->d_inode->i_mode)
582 ) {
583 kerror("inode %lu is not a file or directory",
584 next->d_inode->i_ino);
585 ret = -ENOBUFS;
586 goto error;
587 }
588 }
589
590 /* process the next component */
591 if (key) {
592 _debug("advance");
593 mutex_unlock(&dir->d_inode->i_mutex);
594 dput(dir);
595 dir = next;
596 next = NULL;
597 goto advance;
598 }
599
600 /* we've found the object we were looking for */
601 object->dentry = next;
602
603 /* if we've found that the terminal object exists, then we need to
604 * check its attributes and delete it if it's out of date */
605 if (!object->new) {
606 _debug("validate '%*.*s'",
607 next->d_name.len, next->d_name.len, next->d_name.name);
608
609 ret = cachefiles_check_object_xattr(object, auxdata);
610 if (ret == -ESTALE) {
611 /* delete the object (the deleter drops the directory
612 * mutex) */
613 object->dentry = NULL;
614
c61ea31d 615 ret = cachefiles_bury_object(cache, dir, next, true);
9ae326a6
DH		 616 dput(next);
617 next = NULL;
618
619 if (ret < 0)
620 goto delete_error;
621
622 _debug("redo lookup");
623 goto lookup_again;
624 }
625 }
626
627 /* note that we're now using this object */
fee096de 628 ret = cachefiles_mark_object_active(cache, object);
9ae326a6
DH		 629
630 mutex_unlock(&dir->d_inode->i_mutex);
631 dput(dir);
632 dir = NULL;
633
fee096de
DH		 634 if (ret == -ETIMEDOUT)
635 goto mark_active_timed_out;
636
9ae326a6
DH		 637 _debug("=== OBTAINED_OBJECT ===");
638
639 if (object->new) {
640 /* attach data to a newly constructed terminal object */
641 ret = cachefiles_set_object_xattr(object, auxdata);
642 if (ret < 0)
643 goto check_error;
644 } else {
645 /* always update the atime on an object we've just looked up
646 * (this is used to keep track of culling, and atimes are only
647 * updated by read, write and readdir but not lookup or
648 * open) */
68ac1234
AV		 649 path.dentry = next;
650 touch_atime(&path);
9ae326a6
DH		 651 }
652
653 /* open a file interface onto a data file */
654 if (object->type != FSCACHE_COOKIE_TYPE_INDEX) {
655 if (S_ISREG(object->dentry->d_inode->i_mode)) {
656 const struct address_space_operations *aops;
657
658 ret = -EPERM;
659 aops = object->dentry->d_inode->i_mapping->a_ops;
660 if (!aops->bmap)
661 goto check_error;
662
663 object->backer = object->dentry;
664 } else {
665 BUG(); // TODO: open file in data-class subdir
666 }
667 }
668
669 object->new = 0;
670 fscache_obtained_object(&object->fscache);
671
672 _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino);
673 return 0;
674
675create_error:
676 _debug("create error %d", ret);
677 if (ret == -EIO)
678 cachefiles_io_error(cache, "Create/mkdir failed");
679 goto error;
680
fee096de
DH		 681mark_active_timed_out:
682 _debug("mark active timed out");
683 goto release_dentry;
684
9ae326a6
DH		 685check_error:
686 _debug("check error %d", ret);
687 write_lock(&cache->active_lock);
688 rb_erase(&object->active_node, &cache->active_nodes);
689 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
690 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
691 write_unlock(&cache->active_lock);
fee096de 692release_dentry:
9ae326a6
DH		 693 dput(object->dentry);
694 object->dentry = NULL;
695 goto error_out;
696
697delete_error:
698 _debug("delete error %d", ret);
699 goto error_out2;
700
701lookup_error:
702 _debug("lookup error %ld", PTR_ERR(next));
703 ret = PTR_ERR(next);
704 if (ret == -EIO)
705 cachefiles_io_error(cache, "Lookup failed");
706 next = NULL;
707error:
708 mutex_unlock(&dir->d_inode->i_mutex);
709 dput(next);
710error_out2:
711 dput(dir);
712error_out:
9ae326a6
DH		 713 _leave(" = error %d", -ret);
714 return ret;
715}
716
717/*
718 * get a subdirectory
719 */
720struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
721 struct dentry *dir,
722 const char *dirname)
723{
724 struct dentry *subdir;
725 unsigned long start;
82140443 726 struct path path;
9ae326a6
DH		 727 int ret;
728
729 _enter(",,%s", dirname);
730
731 /* search the current directory for the element name */
732 mutex_lock(&dir->d_inode->i_mutex);
733
734 start = jiffies;
735 subdir = lookup_one_len(dirname, dir, strlen(dirname));
736 cachefiles_hist(cachefiles_lookup_histogram, start);
737 if (IS_ERR(subdir)) {
738 if (PTR_ERR(subdir) == -ENOMEM)
739 goto nomem_d_alloc;
740 goto lookup_error;
741 }
742
743 _debug("subdir -> %p %s",
744 subdir, subdir->d_inode ? "positive" : "negative");
745
746 /* we need to create the subdir if it doesn't exist yet */
747 if (!subdir->d_inode) {
748 ret = cachefiles_has_space(cache, 1, 0);
749 if (ret < 0)
750 goto mkdir_error;
751
752 _debug("attempt mkdir");
753
82140443
DH		 754 path.mnt = cache->mnt;
755 path.dentry = dir;
756 ret = security_path_mkdir(&path, subdir, 0700);
757 if (ret < 0)
758 goto mkdir_error;
9ae326a6
DH		 759 ret = vfs_mkdir(dir->d_inode, subdir, 0700);
760 if (ret < 0)
761 goto mkdir_error;
762
763 ASSERT(subdir->d_inode);
764
765 _debug("mkdir -> %p{%p{ino=%lu}}",
766 subdir,
767 subdir->d_inode,
768 subdir->d_inode->i_ino);
769 }
770
771 mutex_unlock(&dir->d_inode->i_mutex);
772
773 /* we need to make sure the subdir is a directory */
774 ASSERT(subdir->d_inode);
775
776 if (!S_ISDIR(subdir->d_inode->i_mode)) {
777 kerror("%s is not a directory", dirname);
778 ret = -EIO;
779 goto check_error;
780 }
781
782 ret = -EPERM;
783 if (!subdir->d_inode->i_op ||
784 !subdir->d_inode->i_op->setxattr ||
785 !subdir->d_inode->i_op->getxattr ||
786 !subdir->d_inode->i_op->lookup ||
787 !subdir->d_inode->i_op->mkdir ||
788 !subdir->d_inode->i_op->create ||
789 !subdir->d_inode->i_op->rename ||
790 !subdir->d_inode->i_op->rmdir ||
791 !subdir->d_inode->i_op->unlink)
792 goto check_error;
793
794 _leave(" = [%lu]", subdir->d_inode->i_ino);
795 return subdir;
796
797check_error:
798 dput(subdir);
799 _leave(" = %d [check]", ret);
800 return ERR_PTR(ret);
801
802mkdir_error:
803 mutex_unlock(&dir->d_inode->i_mutex);
804 dput(subdir);
805 kerror("mkdir %s failed with error %d", dirname, ret);
806 return ERR_PTR(ret);
807
808lookup_error:
809 mutex_unlock(&dir->d_inode->i_mutex);
810 ret = PTR_ERR(subdir);
811 kerror("Lookup %s failed with error %d", dirname, ret);
812 return ERR_PTR(ret);
813
814nomem_d_alloc:
815 mutex_unlock(&dir->d_inode->i_mutex);
816 _leave(" = -ENOMEM");
817 return ERR_PTR(-ENOMEM);
818}
819
820/*
821 * find out if an object is in use or not
822 * - if finds object and it's not in use:
823 * - returns a pointer to the object and a reference on it
824 * - returns with the directory locked
825 */
826static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
827 struct dentry *dir,
828 char *filename)
829{
830 struct cachefiles_object *object;
831 struct rb_node *_n;
832 struct dentry *victim;
833 unsigned long start;
834 int ret;
835
836 //_enter(",%*.*s/,%s",
837 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
838
839 /* look up the victim */
840 mutex_lock_nested(&dir->d_inode->i_mutex, 1);
841
842 start = jiffies;
843 victim = lookup_one_len(filename, dir, strlen(filename));
844 cachefiles_hist(cachefiles_lookup_histogram, start);
845 if (IS_ERR(victim))
846 goto lookup_error;
847
848 //_debug("victim -> %p %s",
849 // victim, victim->d_inode ? "positive" : "negative");
850
851 /* if the object is no longer there then we probably retired the object
852 * at the netfs's request whilst the cull was in progress
853 */
854 if (!victim->d_inode) {
855 mutex_unlock(&dir->d_inode->i_mutex);
856 dput(victim);
857 _leave(" = -ENOENT [absent]");
858 return ERR_PTR(-ENOENT);
859 }
860
861 /* check to see if we're using this object */
862 read_lock(&cache->active_lock);
863
864 _n = cache->active_nodes.rb_node;
865
866 while (_n) {
867 object = rb_entry(_n, struct cachefiles_object, active_node);
868
869 if (object->dentry > victim)
870 _n = _n->rb_left;
871 else if (object->dentry < victim)
872 _n = _n->rb_right;
873 else
874 goto object_in_use;
875 }
876
877 read_unlock(&cache->active_lock);
878
879 //_leave(" = %p", victim);
880 return victim;
881
882object_in_use:
883 read_unlock(&cache->active_lock);
884 mutex_unlock(&dir->d_inode->i_mutex);
885 dput(victim);
886 //_leave(" = -EBUSY [in use]");
887 return ERR_PTR(-EBUSY);
888
889lookup_error:
890 mutex_unlock(&dir->d_inode->i_mutex);
891 ret = PTR_ERR(victim);
892 if (ret == -ENOENT) {
893 /* file or dir now absent - probably retired by netfs */
894 _leave(" = -ESTALE [absent]");
895 return ERR_PTR(-ESTALE);
896 }
897
898 if (ret == -EIO) {
899 cachefiles_io_error(cache, "Lookup failed");
900 } else if (ret != -ENOMEM) {
901 kerror("Internal error: %d", ret);
902 ret = -EIO;
903 }
904
905 _leave(" = %d", ret);
906 return ERR_PTR(ret);
907}
908
909/*
910 * cull an object if it's not in use
911 * - called only by cache manager daemon
912 */
913int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
914 char *filename)
915{
916 struct dentry *victim;
917 int ret;
918
919 _enter(",%*.*s/,%s",
920 dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
921
922 victim = cachefiles_check_active(cache, dir, filename);
923 if (IS_ERR(victim))
924 return PTR_ERR(victim);
925
926 _debug("victim -> %p %s",
927 victim, victim->d_inode ? "positive" : "negative");
928
929 /* okay... the victim is not being used so we can cull it
930 * - start by marking it as stale
931 */
932 _debug("victim is cullable");
933
934 ret = cachefiles_remove_object_xattr(cache, victim);
935 if (ret < 0)
936 goto error_unlock;
937
938 /* actually remove the victim (drops the dir mutex) */
939 _debug("bury");
940
c61ea31d 941 ret = cachefiles_bury_object(cache, dir, victim, false);
9ae326a6
DH		 942 if (ret < 0)
943 goto error;
944
945 dput(victim);
946 _leave(" = 0");
947 return 0;
948
949error_unlock:
950 mutex_unlock(&dir->d_inode->i_mutex);
951error:
952 dput(victim);
953 if (ret == -ENOENT) {
954 /* file or dir now absent - probably retired by netfs */
955 _leave(" = -ESTALE [absent]");
956 return -ESTALE;
957 }
958
959 if (ret != -ENOMEM) {
960 kerror("Internal error: %d", ret);
961 ret = -EIO;
962 }
963
964 _leave(" = %d", ret);
965 return ret;
966}
967
968/*
969 * find out if an object is in use or not
970 * - called only by cache manager daemon
971 * - returns -EBUSY or 0 to indicate whether an object is in use or not
972 */
973int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
974 char *filename)
975{
976 struct dentry *victim;
977
978 //_enter(",%*.*s/,%s",
979 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
980
981 victim = cachefiles_check_active(cache, dir, filename);
982 if (IS_ERR(victim))
983 return PTR_ERR(victim);
984
985 mutex_unlock(&dir->d_inode->i_mutex);
986 dput(victim);
987 //_leave(" = 0");
988 return 0;
989}
Linux kernel - Deliverables
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