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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* CacheFiles path walking and related routines
3 *
4 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/fs.h>
9#include <linux/namei.h>
10#include "internal.h"
11
12/*
13 * Mark the backing file as being a cache file if it's not already in use. The
14 * mark tells the culling request command that it's not allowed to cull the
15 * file or directory. The caller must hold the inode lock.
16 */
17static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
18 struct inode *inode)
19{
20 bool can_use = false;
21
22 if (!(inode->i_flags & S_KERNEL_FILE)) {
23 inode->i_flags |= S_KERNEL_FILE;
24 trace_cachefiles_mark_active(object, inode);
25 can_use = true;
26 } else {
27 trace_cachefiles_mark_failed(object, inode);
28 }
29
30 return can_use;
31}
32
33static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
34 struct inode *inode)
35{
36 bool can_use;
37
38 inode_lock(inode);
39 can_use = __cachefiles_mark_inode_in_use(object, inode);
40 inode_unlock(inode);
41 return can_use;
42}
43
44/*
45 * Unmark a backing inode. The caller must hold the inode lock.
46 */
47static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
48 struct inode *inode)
49{
50 inode->i_flags &= ~S_KERNEL_FILE;
51 trace_cachefiles_mark_inactive(object, inode);
52}
53
54static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
55 struct inode *inode)
56{
57 inode_lock(inode);
58 __cachefiles_unmark_inode_in_use(object, inode);
59 inode_unlock(inode);
60}
61
62/*
63 * Unmark a backing inode and tell cachefilesd that there's something that can
64 * be culled.
65 */
66void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
67 struct file *file)
68{
69 struct cachefiles_cache *cache = object->volume->cache;
70 struct inode *inode = file_inode(file);
71
72 cachefiles_do_unmark_inode_in_use(object, inode);
73
74 if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
75 atomic_long_add(inode->i_blocks, &cache->b_released);
76 if (atomic_inc_return(&cache->f_released))
77 cachefiles_state_changed(cache);
78 }
79}
80
81/*
82 * get a subdirectory
83 */
84struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
85 struct dentry *dir,
86 const char *dirname,
87 bool *_is_new)
88{
89 struct dentry *subdir;
90 struct path path;
91 int ret;
92
93 _enter(",,%s", dirname);
94
95 /* search the current directory for the element name */
96 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
97
98retry:
99 ret = cachefiles_inject_read_error();
100 if (ret == 0)
101 subdir = lookup_one_len(dirname, dir, strlen(dirname));
102 else
103 subdir = ERR_PTR(ret);
104 trace_cachefiles_lookup(NULL, dir, subdir);
105 if (IS_ERR(subdir)) {
106 trace_cachefiles_vfs_error(NULL, d_backing_inode(dir),
107 PTR_ERR(subdir),
108 cachefiles_trace_lookup_error);
109 if (PTR_ERR(subdir) == -ENOMEM)
110 goto nomem_d_alloc;
111 goto lookup_error;
112 }
113
114 _debug("subdir -> %pd %s",
115 subdir, d_backing_inode(subdir) ? "positive" : "negative");
116
117 /* we need to create the subdir if it doesn't exist yet */
118 if (d_is_negative(subdir)) {
119 ret = cachefiles_has_space(cache, 1, 0,
120 cachefiles_has_space_for_create);
121 if (ret < 0)
122 goto mkdir_error;
123
124 _debug("attempt mkdir");
125
126 path.mnt = cache->mnt;
127 path.dentry = dir;
128 ret = security_path_mkdir(&path, subdir, 0700);
129 if (ret < 0)
130 goto mkdir_error;
131 ret = cachefiles_inject_write_error();
132 if (ret == 0)
133 ret = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700);
134 if (ret < 0) {
135 trace_cachefiles_vfs_error(NULL, d_inode(dir), ret,
136 cachefiles_trace_mkdir_error);
137 goto mkdir_error;
138 }
139 trace_cachefiles_mkdir(dir, subdir);
140
141 if (unlikely(d_unhashed(subdir))) {
142 cachefiles_put_directory(subdir);
143 goto retry;
144 }
145 ASSERT(d_backing_inode(subdir));
146
147 _debug("mkdir -> %pd{ino=%lu}",
148 subdir, d_backing_inode(subdir)->i_ino);
149 if (_is_new)
150 *_is_new = true;
151 }
152
153 /* Tell rmdir() it's not allowed to delete the subdir */
154 inode_lock(d_inode(subdir));
155 inode_unlock(d_inode(dir));
156
157 if (!__cachefiles_mark_inode_in_use(NULL, d_inode(subdir))) {
158 pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
159 subdir, d_inode(subdir)->i_ino);
160 goto mark_error;
161 }
162
163 inode_unlock(d_inode(subdir));
164
165 /* we need to make sure the subdir is a directory */
166 ASSERT(d_backing_inode(subdir));
167
168 if (!d_can_lookup(subdir)) {
169 pr_err("%s is not a directory\n", dirname);
170 ret = -EIO;
171 goto check_error;
172 }
173
174 ret = -EPERM;
175 if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
176 !d_backing_inode(subdir)->i_op->lookup ||
177 !d_backing_inode(subdir)->i_op->mkdir ||
178 !d_backing_inode(subdir)->i_op->rename ||
179 !d_backing_inode(subdir)->i_op->rmdir ||
180 !d_backing_inode(subdir)->i_op->unlink)
181 goto check_error;
182
183 _leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
184 return subdir;
185
186check_error:
187 cachefiles_put_directory(subdir);
188 _leave(" = %d [check]", ret);
189 return ERR_PTR(ret);
190
191mark_error:
192 inode_unlock(d_inode(subdir));
193 dput(subdir);
194 return ERR_PTR(-EBUSY);
195
196mkdir_error:
197 inode_unlock(d_inode(dir));
198 dput(subdir);
199 pr_err("mkdir %s failed with error %d\n", dirname, ret);
200 return ERR_PTR(ret);
201
202lookup_error:
203 inode_unlock(d_inode(dir));
204 ret = PTR_ERR(subdir);
205 pr_err("Lookup %s failed with error %d\n", dirname, ret);
206 return ERR_PTR(ret);
207
208nomem_d_alloc:
209 inode_unlock(d_inode(dir));
210 _leave(" = -ENOMEM");
211 return ERR_PTR(-ENOMEM);
212}
213
214/*
215 * Put a subdirectory.
216 */
217void cachefiles_put_directory(struct dentry *dir)
218{
219 if (dir) {
220 cachefiles_do_unmark_inode_in_use(NULL, d_inode(dir));
221 dput(dir);
222 }
223}
224
225/*
226 * Remove a regular file from the cache.
227 */
228static int cachefiles_unlink(struct cachefiles_cache *cache,
229 struct cachefiles_object *object,
230 struct dentry *dir, struct dentry *dentry,
231 enum fscache_why_object_killed why)
232{
233 struct path path = {
234 .mnt = cache->mnt,
235 .dentry = dir,
236 };
237 int ret;
238
239 trace_cachefiles_unlink(object, d_inode(dentry)->i_ino, why);
240 ret = security_path_unlink(&path, dentry);
241 if (ret < 0) {
242 cachefiles_io_error(cache, "Unlink security error");
243 return ret;
244 }
245
246 ret = cachefiles_inject_remove_error();
247 if (ret == 0) {
248 ret = vfs_unlink(&nop_mnt_idmap, d_backing_inode(dir), dentry, NULL);
249 if (ret == -EIO)
250 cachefiles_io_error(cache, "Unlink failed");
251 }
252 if (ret != 0)
253 trace_cachefiles_vfs_error(object, d_backing_inode(dir), ret,
254 cachefiles_trace_unlink_error);
255 return ret;
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 */
264int cachefiles_bury_object(struct cachefiles_cache *cache,
265 struct cachefiles_object *object,
266 struct dentry *dir,
267 struct dentry *rep,
268 enum fscache_why_object_killed why)
269{
270 struct dentry *grave, *trap;
271 struct path path, path_to_graveyard;
272 char nbuffer[8 + 8 + 1];
273 int ret;
274
275 _enter(",'%pd','%pd'", dir, rep);
276
277 if (rep->d_parent != dir) {
278 inode_unlock(d_inode(dir));
279 _leave(" = -ESTALE");
280 return -ESTALE;
281 }
282
283 /* non-directories can just be unlinked */
284 if (!d_is_dir(rep)) {
285 dget(rep); /* Stop the dentry being negated if it's only pinned
286 * by a file struct.
287 */
288 ret = cachefiles_unlink(cache, object, dir, rep, why);
289 dput(rep);
290
291 inode_unlock(d_inode(dir));
292 _leave(" = %d", ret);
293 return ret;
294 }
295
296 /* directories have to be moved to the graveyard */
297 _debug("move stale object to graveyard");
298 inode_unlock(d_inode(dir));
299
300try_again:
301 /* first step is to make up a grave dentry in the graveyard */
302 sprintf(nbuffer, "%08x%08x",
303 (uint32_t) ktime_get_real_seconds(),
304 (uint32_t) atomic_inc_return(&cache->gravecounter));
305
306 /* do the multiway lock magic */
307 trap = lock_rename(cache->graveyard, dir);
308 if (IS_ERR(trap))
309 return PTR_ERR(trap);
310
311 /* do some checks before getting the grave dentry */
312 if (rep->d_parent != dir || IS_DEADDIR(d_inode(rep))) {
313 /* the entry was probably culled when we dropped the parent dir
314 * lock */
315 unlock_rename(cache->graveyard, dir);
316 _leave(" = 0 [culled?]");
317 return 0;
318 }
319
320 if (!d_can_lookup(cache->graveyard)) {
321 unlock_rename(cache->graveyard, dir);
322 cachefiles_io_error(cache, "Graveyard no longer a directory");
323 return -EIO;
324 }
325
326 if (trap == rep) {
327 unlock_rename(cache->graveyard, dir);
328 cachefiles_io_error(cache, "May not make directory loop");
329 return -EIO;
330 }
331
332 if (d_mountpoint(rep)) {
333 unlock_rename(cache->graveyard, dir);
334 cachefiles_io_error(cache, "Mountpoint in cache");
335 return -EIO;
336 }
337
338 grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
339 if (IS_ERR(grave)) {
340 unlock_rename(cache->graveyard, dir);
341 trace_cachefiles_vfs_error(object, d_inode(cache->graveyard),
342 PTR_ERR(grave),
343 cachefiles_trace_lookup_error);
344
345 if (PTR_ERR(grave) == -ENOMEM) {
346 _leave(" = -ENOMEM");
347 return -ENOMEM;
348 }
349
350 cachefiles_io_error(cache, "Lookup error %ld", PTR_ERR(grave));
351 return -EIO;
352 }
353
354 if (d_is_positive(grave)) {
355 unlock_rename(cache->graveyard, dir);
356 dput(grave);
357 grave = NULL;
358 cond_resched();
359 goto try_again;
360 }
361
362 if (d_mountpoint(grave)) {
363 unlock_rename(cache->graveyard, dir);
364 dput(grave);
365 cachefiles_io_error(cache, "Mountpoint in graveyard");
366 return -EIO;
367 }
368
369 /* target should not be an ancestor of source */
370 if (trap == grave) {
371 unlock_rename(cache->graveyard, dir);
372 dput(grave);
373 cachefiles_io_error(cache, "May not make directory loop");
374 return -EIO;
375 }
376
377 /* attempt the rename */
378 path.mnt = cache->mnt;
379 path.dentry = dir;
380 path_to_graveyard.mnt = cache->mnt;
381 path_to_graveyard.dentry = cache->graveyard;
382 ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
383 if (ret < 0) {
384 cachefiles_io_error(cache, "Rename security error %d", ret);
385 } else {
386 struct renamedata rd = {
387 .old_mnt_idmap = &nop_mnt_idmap,
388 .old_dir = d_inode(dir),
389 .old_dentry = rep,
390 .new_mnt_idmap = &nop_mnt_idmap,
391 .new_dir = d_inode(cache->graveyard),
392 .new_dentry = grave,
393 };
394 trace_cachefiles_rename(object, d_inode(rep)->i_ino, why);
395 ret = cachefiles_inject_read_error();
396 if (ret == 0)
397 ret = vfs_rename(&rd);
398 if (ret != 0)
399 trace_cachefiles_vfs_error(object, d_inode(dir), ret,
400 cachefiles_trace_rename_error);
401 if (ret != 0 && ret != -ENOMEM)
402 cachefiles_io_error(cache,
403 "Rename failed with error %d", ret);
404 }
405
406 __cachefiles_unmark_inode_in_use(object, d_inode(rep));
407 unlock_rename(cache->graveyard, dir);
408 dput(grave);
409 _leave(" = 0");
410 return 0;
411}
412
413/*
414 * Delete a cache file.
415 */
416int cachefiles_delete_object(struct cachefiles_object *object,
417 enum fscache_why_object_killed why)
418{
419 struct cachefiles_volume *volume = object->volume;
420 struct dentry *dentry = object->file->f_path.dentry;
421 struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
422 int ret;
423
424 _enter(",OBJ%x{%pD}", object->debug_id, object->file);
425
426 /* Stop the dentry being negated if it's only pinned by a file struct. */
427 dget(dentry);
428
429 inode_lock_nested(d_backing_inode(fan), I_MUTEX_PARENT);
430 ret = cachefiles_unlink(volume->cache, object, fan, dentry, why);
431 inode_unlock(d_backing_inode(fan));
432 dput(dentry);
433 return ret;
434}
435
436/*
437 * Create a temporary file and leave it unattached and un-xattr'd until the
438 * time comes to discard the object from memory.
439 */
440struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
441{
442 struct cachefiles_volume *volume = object->volume;
443 struct cachefiles_cache *cache = volume->cache;
444 const struct cred *saved_cred;
445 struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
446 struct file *file;
447 const struct path parentpath = { .mnt = cache->mnt, .dentry = fan };
448 uint64_t ni_size;
449 long ret;
450
451
452 cachefiles_begin_secure(cache, &saved_cred);
453
454 ret = cachefiles_inject_write_error();
455 if (ret == 0) {
456 file = kernel_tmpfile_open(&nop_mnt_idmap, &parentpath,
457 S_IFREG | 0600,
458 O_RDWR | O_LARGEFILE | O_DIRECT,
459 cache->cache_cred);
460 ret = PTR_ERR_OR_ZERO(file);
461 }
462 if (ret) {
463 trace_cachefiles_vfs_error(object, d_inode(fan), ret,
464 cachefiles_trace_tmpfile_error);
465 if (ret == -EIO)
466 cachefiles_io_error_obj(object, "Failed to create tmpfile");
467 goto err;
468 }
469
470 trace_cachefiles_tmpfile(object, file_inode(file));
471
472 /* This is a newly created file with no other possible user */
473 if (!cachefiles_mark_inode_in_use(object, file_inode(file)))
474 WARN_ON(1);
475
476 ret = cachefiles_ondemand_init_object(object);
477 if (ret < 0)
478 goto err_unuse;
479
480 ni_size = object->cookie->object_size;
481 ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
482
483 if (ni_size > 0) {
484 trace_cachefiles_trunc(object, file_inode(file), 0, ni_size,
485 cachefiles_trunc_expand_tmpfile);
486 ret = cachefiles_inject_write_error();
487 if (ret == 0)
488 ret = vfs_truncate(&file->f_path, ni_size);
489 if (ret < 0) {
490 trace_cachefiles_vfs_error(
491 object, file_inode(file), ret,
492 cachefiles_trace_trunc_error);
493 goto err_unuse;
494 }
495 }
496
497 ret = -EINVAL;
498 if (unlikely(!file->f_op->read_iter) ||
499 unlikely(!file->f_op->write_iter)) {
500 fput(file);
501 pr_notice("Cache does not support read_iter and write_iter\n");
502 goto err_unuse;
503 }
504out:
505 cachefiles_end_secure(cache, saved_cred);
506 return file;
507
508err_unuse:
509 cachefiles_do_unmark_inode_in_use(object, file_inode(file));
510 fput(file);
511err:
512 file = ERR_PTR(ret);
513 goto out;
514}
515
516/*
517 * Create a new file.
518 */
519static bool cachefiles_create_file(struct cachefiles_object *object)
520{
521 struct file *file;
522 int ret;
523
524 ret = cachefiles_has_space(object->volume->cache, 1, 0,
525 cachefiles_has_space_for_create);
526 if (ret < 0)
527 return false;
528
529 file = cachefiles_create_tmpfile(object);
530 if (IS_ERR(file))
531 return false;
532
533 set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
534 set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
535 _debug("create -> %pD{ino=%lu}", file, file_inode(file)->i_ino);
536 object->file = file;
537 return true;
538}
539
540/*
541 * Open an existing file, checking its attributes and replacing it if it is
542 * stale.
543 */
544static bool cachefiles_open_file(struct cachefiles_object *object,
545 struct dentry *dentry)
546{
547 struct cachefiles_cache *cache = object->volume->cache;
548 struct file *file;
549 struct path path;
550 int ret;
551
552 _enter("%pd", dentry);
553
554 if (!cachefiles_mark_inode_in_use(object, d_inode(dentry))) {
555 pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
556 dentry, d_inode(dentry)->i_ino);
557 return false;
558 }
559
560 /* We need to open a file interface onto a data file now as we can't do
561 * it on demand because writeback called from do_exit() sees
562 * current->fs == NULL - which breaks d_path() called from ext4 open.
563 */
564 path.mnt = cache->mnt;
565 path.dentry = dentry;
566 file = kernel_file_open(&path, O_RDWR | O_LARGEFILE | O_DIRECT,
567 d_backing_inode(dentry), cache->cache_cred);
568 if (IS_ERR(file)) {
569 trace_cachefiles_vfs_error(object, d_backing_inode(dentry),
570 PTR_ERR(file),
571 cachefiles_trace_open_error);
572 goto error;
573 }
574
575 if (unlikely(!file->f_op->read_iter) ||
576 unlikely(!file->f_op->write_iter)) {
577 pr_notice("Cache does not support read_iter and write_iter\n");
578 goto error_fput;
579 }
580 _debug("file -> %pd positive", dentry);
581
582 ret = cachefiles_ondemand_init_object(object);
583 if (ret < 0)
584 goto error_fput;
585
586 ret = cachefiles_check_auxdata(object, file);
587 if (ret < 0)
588 goto check_failed;
589
590 clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &object->cookie->flags);
591
592 object->file = file;
593
594 /* Always update the atime on an object we've just looked up (this is
595 * used to keep track of culling, and atimes are only updated by read,
596 * write and readdir but not lookup or open).
597 */
598 touch_atime(&file->f_path);
599 dput(dentry);
600 return true;
601
602check_failed:
603 fscache_cookie_lookup_negative(object->cookie);
604 cachefiles_unmark_inode_in_use(object, file);
605 fput(file);
606 dput(dentry);
607 if (ret == -ESTALE)
608 return cachefiles_create_file(object);
609 return false;
610
611error_fput:
612 fput(file);
613error:
614 cachefiles_do_unmark_inode_in_use(object, d_inode(dentry));
615 dput(dentry);
616 return false;
617}
618
619/*
620 * walk from the parent object to the child object through the backing
621 * filesystem, creating directories as we go
622 */
623bool cachefiles_look_up_object(struct cachefiles_object *object)
624{
625 struct cachefiles_volume *volume = object->volume;
626 struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash];
627 int ret;
628
629 _enter("OBJ%x,%s,", object->debug_id, object->d_name);
630
631 /* Look up path "cache/vol/fanout/file". */
632 ret = cachefiles_inject_read_error();
633 if (ret == 0)
634 dentry = lookup_positive_unlocked(object->d_name, fan,
635 object->d_name_len);
636 else
637 dentry = ERR_PTR(ret);
638 trace_cachefiles_lookup(object, fan, dentry);
639 if (IS_ERR(dentry)) {
640 if (dentry == ERR_PTR(-ENOENT))
641 goto new_file;
642 if (dentry == ERR_PTR(-EIO))
643 cachefiles_io_error_obj(object, "Lookup failed");
644 return false;
645 }
646
647 if (!d_is_reg(dentry)) {
648 pr_err("%pd is not a file\n", dentry);
649 inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
650 ret = cachefiles_bury_object(volume->cache, object, fan, dentry,
651 FSCACHE_OBJECT_IS_WEIRD);
652 dput(dentry);
653 if (ret < 0)
654 return false;
655 goto new_file;
656 }
657
658 if (!cachefiles_open_file(object, dentry))
659 return false;
660
661 _leave(" = t [%lu]", file_inode(object->file)->i_ino);
662 return true;
663
664new_file:
665 fscache_cookie_lookup_negative(object->cookie);
666 return cachefiles_create_file(object);
667}
668
669/*
670 * Attempt to link a temporary file into its rightful place in the cache.
671 */
672bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
673 struct cachefiles_object *object)
674{
675 struct cachefiles_volume *volume = object->volume;
676 struct dentry *dentry, *fan = volume->fanout[(u8)object->cookie->key_hash];
677 bool success = false;
678 int ret;
679
680 _enter(",%pD", object->file);
681
682 inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
683 ret = cachefiles_inject_read_error();
684 if (ret == 0)
685 dentry = lookup_one_len(object->d_name, fan, object->d_name_len);
686 else
687 dentry = ERR_PTR(ret);
688 if (IS_ERR(dentry)) {
689 trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry),
690 cachefiles_trace_lookup_error);
691 _debug("lookup fail %ld", PTR_ERR(dentry));
692 goto out_unlock;
693 }
694
695 if (!d_is_negative(dentry)) {
696 if (d_backing_inode(dentry) == file_inode(object->file)) {
697 success = true;
698 goto out_dput;
699 }
700
701 ret = cachefiles_unlink(volume->cache, object, fan, dentry,
702 FSCACHE_OBJECT_IS_STALE);
703 if (ret < 0)
704 goto out_dput;
705
706 dput(dentry);
707 ret = cachefiles_inject_read_error();
708 if (ret == 0)
709 dentry = lookup_one_len(object->d_name, fan, object->d_name_len);
710 else
711 dentry = ERR_PTR(ret);
712 if (IS_ERR(dentry)) {
713 trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(dentry),
714 cachefiles_trace_lookup_error);
715 _debug("lookup fail %ld", PTR_ERR(dentry));
716 goto out_unlock;
717 }
718 }
719
720 ret = cachefiles_inject_read_error();
721 if (ret == 0)
722 ret = vfs_link(object->file->f_path.dentry, &nop_mnt_idmap,
723 d_inode(fan), dentry, NULL);
724 if (ret < 0) {
725 trace_cachefiles_vfs_error(object, d_inode(fan), ret,
726 cachefiles_trace_link_error);
727 _debug("link fail %d", ret);
728 } else {
729 trace_cachefiles_link(object, file_inode(object->file));
730 spin_lock(&object->lock);
731 /* TODO: Do we want to switch the file pointer to the new dentry? */
732 clear_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
733 spin_unlock(&object->lock);
734 success = true;
735 }
736
737out_dput:
738 dput(dentry);
739out_unlock:
740 inode_unlock(d_inode(fan));
741 _leave(" = %u", success);
742 return success;
743}
744
745/*
746 * Look up an inode to be checked or culled. Return -EBUSY if the inode is
747 * marked in use.
748 */
749static struct dentry *cachefiles_lookup_for_cull(struct cachefiles_cache *cache,
750 struct dentry *dir,
751 char *filename)
752{
753 struct dentry *victim;
754 int ret = -ENOENT;
755
756 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
757
758 victim = lookup_one_len(filename, dir, strlen(filename));
759 if (IS_ERR(victim))
760 goto lookup_error;
761 if (d_is_negative(victim))
762 goto lookup_put;
763 if (d_inode(victim)->i_flags & S_KERNEL_FILE)
764 goto lookup_busy;
765 return victim;
766
767lookup_busy:
768 ret = -EBUSY;
769lookup_put:
770 inode_unlock(d_inode(dir));
771 dput(victim);
772 return ERR_PTR(ret);
773
774lookup_error:
775 inode_unlock(d_inode(dir));
776 ret = PTR_ERR(victim);
777 if (ret == -ENOENT)
778 return ERR_PTR(-ESTALE); /* Probably got retired by the netfs */
779
780 if (ret == -EIO) {
781 cachefiles_io_error(cache, "Lookup failed");
782 } else if (ret != -ENOMEM) {
783 pr_err("Internal error: %d\n", ret);
784 ret = -EIO;
785 }
786
787 return ERR_PTR(ret);
788}
789
790/*
791 * Cull an object if it's not in use
792 * - called only by cache manager daemon
793 */
794int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
795 char *filename)
796{
797 struct dentry *victim;
798 struct inode *inode;
799 int ret;
800
801 _enter(",%pd/,%s", dir, filename);
802
803 victim = cachefiles_lookup_for_cull(cache, dir, filename);
804 if (IS_ERR(victim))
805 return PTR_ERR(victim);
806
807 /* check to see if someone is using this object */
808 inode = d_inode(victim);
809 inode_lock(inode);
810 if (inode->i_flags & S_KERNEL_FILE) {
811 ret = -EBUSY;
812 } else {
813 /* Stop the cache from picking it back up */
814 inode->i_flags |= S_KERNEL_FILE;
815 ret = 0;
816 }
817 inode_unlock(inode);
818 if (ret < 0)
819 goto error_unlock;
820
821 ret = cachefiles_bury_object(cache, NULL, dir, victim,
822 FSCACHE_OBJECT_WAS_CULLED);
823 if (ret < 0)
824 goto error;
825
826 fscache_count_culled();
827 dput(victim);
828 _leave(" = 0");
829 return 0;
830
831error_unlock:
832 inode_unlock(d_inode(dir));
833error:
834 dput(victim);
835 if (ret == -ENOENT)
836 return -ESTALE; /* Probably got retired by the netfs */
837
838 if (ret != -ENOMEM) {
839 pr_err("Internal error: %d\n", ret);
840 ret = -EIO;
841 }
842
843 _leave(" = %d", ret);
844 return ret;
845}
846
847/*
848 * Find out if an object is in use or not
849 * - called only by cache manager daemon
850 * - returns -EBUSY or 0 to indicate whether an object is in use or not
851 */
852int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
853 char *filename)
854{
855 struct dentry *victim;
856 int ret = 0;
857
858 victim = cachefiles_lookup_for_cull(cache, dir, filename);
859 if (IS_ERR(victim))
860 return PTR_ERR(victim);
861
862 inode_unlock(d_inode(dir));
863 dput(victim);
864 return ret;
865}
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>
22#include <linux/slab.h>
23#include "internal.h"
24
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);
40 printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
41 prefix, object->fscache.state->name,
42 object->fscache.flags, work_busy(&object->fscache.work),
43 object->fscache.events, object->fscache.event_mask);
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 && cookie->def)
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
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 object->fscache.state->name,
131 dentry);
132
133 if (fscache_object_is_live(&object->fscache)) {
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
147/*
148 * record the fact that an object is now active
149 */
150static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
151 struct cachefiles_object *object)
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
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);
165 BUG();
166 }
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);
189 _leave(" = 0");
190 return 0;
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 (fscache_object_is_live(&object->fscache)) {
196 printk(KERN_ERR "\n");
197 printk(KERN_ERR "CacheFiles: Error:"
198 " Unexpected object collision\n");
199 cachefiles_printk_object(object, xobject);
200 BUG();
201 }
202 atomic_inc(&xobject->usage);
203 write_unlock(&cache->active_lock);
204
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 */
214 if (work_pending(&xobject->fscache.work)) {
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
222 * is done, or the fscache_object is congested */
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;
230
231 requeue = fscache_object_sleep_till_congested(&timeout);
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));
253
254 cache->cache.ops->put_object(&xobject->fscache);
255 goto try_again;
256
257requeue:
258 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
259 cache->cache.ops->put_object(&xobject->fscache);
260 _leave(" = -ETIMEDOUT");
261 return -ETIMEDOUT;
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,
273 struct dentry *rep,
274 bool preemptive)
275{
276 struct dentry *grave, *trap;
277 struct path path, path_to_graveyard;
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
285 _debug("remove %p from %p", rep, dir);
286
287 /* non-directories can just be unlinked */
288 if (!S_ISDIR(rep->d_inode->i_mode)) {
289 _debug("unlink stale object");
290
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, NULL);
298
299 if (preemptive)
300 cachefiles_mark_object_buried(cache, rep);
301 }
302
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 */
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, 0);
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, NULL, 0);
400 if (ret != 0 && ret != -ENOMEM)
401 cachefiles_io_error(cache,
402 "Rename failed with error %d", ret);
403
404 if (preemptive)
405 cachefiles_mark_object_buried(cache, rep);
406 }
407
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
423 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
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
431 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
432
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");
437 mutex_unlock(&dir->d_inode->i_mutex);
438 ret = 0;
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 }
452 }
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;
470 struct path path;
471 unsigned long start;
472 const char *name;
473 int ret, nlen;
474
475 _enter("OBJ%x{%p},OBJ%x,%s,",
476 parent->fscache.debug_id, parent->dentry,
477 object->fscache.debug_id, key);
478
479 cache = container_of(parent->fscache.cache,
480 struct cachefiles_cache, cache);
481 path.mnt = cache->mnt;
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
508 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
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
535 path.dentry = dir;
536 ret = security_path_mkdir(&path, next, 0);
537 if (ret < 0)
538 goto create_error;
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
564 path.dentry = dir;
565 ret = security_path_mknod(&path, next, S_IFREG, 0);
566 if (ret < 0)
567 goto create_error;
568 start = jiffies;
569 ret = vfs_create(dir->d_inode, next, S_IFREG, true);
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
614 ret = cachefiles_bury_object(cache, dir, next, true);
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 */
627 ret = cachefiles_mark_object_active(cache, object);
628
629 mutex_unlock(&dir->d_inode->i_mutex);
630 dput(dir);
631 dir = NULL;
632
633 if (ret == -ETIMEDOUT)
634 goto mark_active_timed_out;
635
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) */
648 path.dentry = next;
649 touch_atime(&path);
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
680mark_active_timed_out:
681 _debug("mark active timed out");
682 goto release_dentry;
683
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);
691release_dentry:
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:
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;
725 struct path path;
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
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;
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->setxattr ||
783 !subdir->d_inode->i_op->getxattr ||
784 !subdir->d_inode->i_op->lookup ||
785 !subdir->d_inode->i_op->mkdir ||
786 !subdir->d_inode->i_op->create ||
787 !subdir->d_inode->i_op->rename ||
788 !subdir->d_inode->i_op->rmdir ||
789 !subdir->d_inode->i_op->unlink)
790 goto check_error;
791
792 _leave(" = [%lu]", subdir->d_inode->i_ino);
793 return subdir;
794
795check_error:
796 dput(subdir);
797 _leave(" = %d [check]", ret);
798 return ERR_PTR(ret);
799
800mkdir_error:
801 mutex_unlock(&dir->d_inode->i_mutex);
802 dput(subdir);
803 kerror("mkdir %s failed with error %d", dirname, ret);
804 return ERR_PTR(ret);
805
806lookup_error:
807 mutex_unlock(&dir->d_inode->i_mutex);
808 ret = PTR_ERR(subdir);
809 kerror("Lookup %s failed with error %d", dirname, ret);
810 return ERR_PTR(ret);
811
812nomem_d_alloc:
813 mutex_unlock(&dir->d_inode->i_mutex);
814 _leave(" = -ENOMEM");
815 return ERR_PTR(-ENOMEM);
816}
817
818/*
819 * find out if an object is in use or not
820 * - if finds object and it's not in use:
821 * - returns a pointer to the object and a reference on it
822 * - returns with the directory locked
823 */
824static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
825 struct dentry *dir,
826 char *filename)
827{
828 struct cachefiles_object *object;
829 struct rb_node *_n;
830 struct dentry *victim;
831 unsigned long start;
832 int ret;
833
834 //_enter(",%*.*s/,%s",
835 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
836
837 /* look up the victim */
838 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
839
840 start = jiffies;
841 victim = lookup_one_len(filename, dir, strlen(filename));
842 cachefiles_hist(cachefiles_lookup_histogram, start);
843 if (IS_ERR(victim))
844 goto lookup_error;
845
846 //_debug("victim -> %p %s",
847 // victim, victim->d_inode ? "positive" : "negative");
848
849 /* if the object is no longer there then we probably retired the object
850 * at the netfs's request whilst the cull was in progress
851 */
852 if (!victim->d_inode) {
853 mutex_unlock(&dir->d_inode->i_mutex);
854 dput(victim);
855 _leave(" = -ENOENT [absent]");
856 return ERR_PTR(-ENOENT);
857 }
858
859 /* check to see if we're using this object */
860 read_lock(&cache->active_lock);
861
862 _n = cache->active_nodes.rb_node;
863
864 while (_n) {
865 object = rb_entry(_n, struct cachefiles_object, active_node);
866
867 if (object->dentry > victim)
868 _n = _n->rb_left;
869 else if (object->dentry < victim)
870 _n = _n->rb_right;
871 else
872 goto object_in_use;
873 }
874
875 read_unlock(&cache->active_lock);
876
877 //_leave(" = %p", victim);
878 return victim;
879
880object_in_use:
881 read_unlock(&cache->active_lock);
882 mutex_unlock(&dir->d_inode->i_mutex);
883 dput(victim);
884 //_leave(" = -EBUSY [in use]");
885 return ERR_PTR(-EBUSY);
886
887lookup_error:
888 mutex_unlock(&dir->d_inode->i_mutex);
889 ret = PTR_ERR(victim);
890 if (ret == -ENOENT) {
891 /* file or dir now absent - probably retired by netfs */
892 _leave(" = -ESTALE [absent]");
893 return ERR_PTR(-ESTALE);
894 }
895
896 if (ret == -EIO) {
897 cachefiles_io_error(cache, "Lookup failed");
898 } else if (ret != -ENOMEM) {
899 kerror("Internal error: %d", ret);
900 ret = -EIO;
901 }
902
903 _leave(" = %d", ret);
904 return ERR_PTR(ret);
905}
906
907/*
908 * cull an object if it's not in use
909 * - called only by cache manager daemon
910 */
911int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
912 char *filename)
913{
914 struct dentry *victim;
915 int ret;
916
917 _enter(",%*.*s/,%s",
918 dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
919
920 victim = cachefiles_check_active(cache, dir, filename);
921 if (IS_ERR(victim))
922 return PTR_ERR(victim);
923
924 _debug("victim -> %p %s",
925 victim, victim->d_inode ? "positive" : "negative");
926
927 /* okay... the victim is not being used so we can cull it
928 * - start by marking it as stale
929 */
930 _debug("victim is cullable");
931
932 ret = cachefiles_remove_object_xattr(cache, victim);
933 if (ret < 0)
934 goto error_unlock;
935
936 /* actually remove the victim (drops the dir mutex) */
937 _debug("bury");
938
939 ret = cachefiles_bury_object(cache, dir, victim, false);
940 if (ret < 0)
941 goto error;
942
943 dput(victim);
944 _leave(" = 0");
945 return 0;
946
947error_unlock:
948 mutex_unlock(&dir->d_inode->i_mutex);
949error:
950 dput(victim);
951 if (ret == -ENOENT) {
952 /* file or dir now absent - probably retired by netfs */
953 _leave(" = -ESTALE [absent]");
954 return -ESTALE;
955 }
956
957 if (ret != -ENOMEM) {
958 kerror("Internal error: %d", ret);
959 ret = -EIO;
960 }
961
962 _leave(" = %d", ret);
963 return ret;
964}
965
966/*
967 * find out if an object is in use or not
968 * - called only by cache manager daemon
969 * - returns -EBUSY or 0 to indicate whether an object is in use or not
970 */
971int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
972 char *filename)
973{
974 struct dentry *victim;
975
976 //_enter(",%*.*s/,%s",
977 // dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
978
979 victim = cachefiles_check_active(cache, dir, filename);
980 if (IS_ERR(victim))
981 return PTR_ERR(victim);
982
983 mutex_unlock(&dir->d_inode->i_mutex);
984 dput(victim);
985 //_leave(" = 0");
986 return 0;
987}