blob: ab857ab9f40d91a375a31030e1872f9ebd704837 [file] [log] [blame]
David Howells9ae326a2009-04-03 16:42:41 +01001/* 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090022#include <linux/slab.h>
David Howells9ae326a2009-04-03 16:42:41 +010023#include "internal.h"
24
David Howellsd0e27b72009-11-19 18:12:02 +000025#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
Fabian Frederick4e1eb882014-06-06 14:37:32 -070038 pr_err("%sobject: OBJ%x\n", prefix, object->fscache.debug_id);
39 pr_err("%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
David Howellscaaef692013-05-10 19:50:26 +010040 prefix, object->fscache.state->name,
Tejun Heo8b8edef2010-07-20 22:09:01 +020041 object->fscache.flags, work_busy(&object->fscache.work),
David Howellsc2d35bf2012-12-05 13:34:47 +000042 object->fscache.events, object->fscache.event_mask);
Fabian Frederick4e1eb882014-06-06 14:37:32 -070043 pr_err("%sops=%u inp=%u exc=%u\n",
David Howellsd0e27b72009-11-19 18:12:02 +000044 prefix, object->fscache.n_ops, object->fscache.n_in_progress,
45 object->fscache.n_exclusive);
Fabian Frederick4e1eb882014-06-06 14:37:32 -070046 pr_err("%sparent=%p\n",
David Howellsd0e27b72009-11-19 18:12:02 +000047 prefix, object->fscache.parent);
48
49 spin_lock(&object->fscache.lock);
50 cookie = object->fscache.cookie;
51 if (cookie) {
Fabian Frederick4e1eb882014-06-06 14:37:32 -070052 pr_err("%scookie=%p [pr=%p nd=%p fl=%lx]\n",
David Howellsd0e27b72009-11-19 18:12:02 +000053 prefix,
54 object->fscache.cookie,
55 object->fscache.cookie->parent,
56 object->fscache.cookie->netfs_data,
57 object->fscache.cookie->flags);
David Howells509bf242013-09-20 14:18:00 +010058 if (keybuf && cookie->def)
David Howellsd0e27b72009-11-19 18:12:02 +000059 keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
60 CACHEFILES_KEYBUF_SIZE);
61 else
62 keylen = 0;
63 } else {
Fabian Frederick4e1eb882014-06-06 14:37:32 -070064 pr_err("%scookie=NULL\n", prefix);
David Howellsd0e27b72009-11-19 18:12:02 +000065 keylen = 0;
66 }
67 spin_unlock(&object->fscache.lock);
68
69 if (keylen) {
Fabian Frederick4e1eb882014-06-06 14:37:32 -070070 pr_err("%skey=[%u] '", prefix, keylen);
David Howellsd0e27b72009-11-19 18:12:02 +000071 for (loop = 0; loop < keylen; loop++)
Fabian Frederick4e1eb882014-06-06 14:37:32 -070072 pr_cont("%02x", keybuf[loop]);
73 pr_cont("'\n");
David Howellsd0e27b72009-11-19 18:12:02 +000074 }
75}
76
77/*
78 * dump debugging info about a pair of objects
79 */
80static noinline void cachefiles_printk_object(struct cachefiles_object *object,
81 struct cachefiles_object *xobject)
82{
83 u8 *keybuf;
84
85 keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO);
86 if (object)
87 __cachefiles_printk_object(object, "", keybuf);
88 if (xobject)
89 __cachefiles_printk_object(xobject, "x", keybuf);
90 kfree(keybuf);
91}
92
David Howells9ae326a2009-04-03 16:42:41 +010093/*
David Howellsc61ea312010-05-11 16:51:39 +010094 * mark the owner of a dentry, if there is one, to indicate that that dentry
95 * has been preemptively deleted
96 * - the caller must hold the i_mutex on the dentry's parent as required to
97 * call vfs_unlink(), vfs_rmdir() or vfs_rename()
98 */
99static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
100 struct dentry *dentry)
101{
102 struct cachefiles_object *object;
103 struct rb_node *p;
104
Al Viroa4555892014-10-21 20:11:25 -0400105 _enter(",'%pd'", dentry);
David Howellsc61ea312010-05-11 16:51:39 +0100106
107 write_lock(&cache->active_lock);
108
109 p = cache->active_nodes.rb_node;
110 while (p) {
111 object = rb_entry(p, struct cachefiles_object, active_node);
112 if (object->dentry > dentry)
113 p = p->rb_left;
114 else if (object->dentry < dentry)
115 p = p->rb_right;
116 else
117 goto found_dentry;
118 }
119
120 write_unlock(&cache->active_lock);
121 _leave(" [no owner]");
122 return;
123
124 /* found the dentry for */
125found_dentry:
126 kdebug("preemptive burial: OBJ%x [%s] %p",
127 object->fscache.debug_id,
David Howellscaaef692013-05-10 19:50:26 +0100128 object->fscache.state->name,
David Howellsc61ea312010-05-11 16:51:39 +0100129 dentry);
130
David Howells493f7bc2013-05-10 19:50:26 +0100131 if (fscache_object_is_live(&object->fscache)) {
Fabian Frederick4e1eb882014-06-06 14:37:32 -0700132 pr_err("\n");
Fabian Frederick0227d6ab2014-06-06 14:37:33 -0700133 pr_err("Error: Can't preemptively bury live object\n");
David Howellsc61ea312010-05-11 16:51:39 +0100134 cachefiles_printk_object(object, NULL);
135 } else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
Fabian Frederick0227d6ab2014-06-06 14:37:33 -0700136 pr_err("Error: Object already preemptively buried\n");
David Howellsc61ea312010-05-11 16:51:39 +0100137 }
138
139 write_unlock(&cache->active_lock);
140 _leave(" [owner marked]");
141}
142
143/*
David Howells9ae326a2009-04-03 16:42:41 +0100144 * record the fact that an object is now active
145 */
David Howellsfee096d2009-11-19 18:12:05 +0000146static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
147 struct cachefiles_object *object)
David Howells9ae326a2009-04-03 16:42:41 +0100148{
149 struct cachefiles_object *xobject;
150 struct rb_node **_p, *_parent = NULL;
151 struct dentry *dentry;
152
153 _enter(",%p", object);
154
155try_again:
156 write_lock(&cache->active_lock);
157
David Howellsd0e27b72009-11-19 18:12:02 +0000158 if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
Fabian Frederick0227d6ab2014-06-06 14:37:33 -0700159 pr_err("Error: Object already active\n");
David Howellsd0e27b72009-11-19 18:12:02 +0000160 cachefiles_printk_object(object, NULL);
David Howells9ae326a2009-04-03 16:42:41 +0100161 BUG();
David Howellsd0e27b72009-11-19 18:12:02 +0000162 }
David Howells9ae326a2009-04-03 16:42:41 +0100163
164 dentry = object->dentry;
165 _p = &cache->active_nodes.rb_node;
166 while (*_p) {
167 _parent = *_p;
168 xobject = rb_entry(_parent,
169 struct cachefiles_object, active_node);
170
171 ASSERT(xobject != object);
172
173 if (xobject->dentry > dentry)
174 _p = &(*_p)->rb_left;
175 else if (xobject->dentry < dentry)
176 _p = &(*_p)->rb_right;
177 else
178 goto wait_for_old_object;
179 }
180
181 rb_link_node(&object->active_node, _parent, _p);
182 rb_insert_color(&object->active_node, &cache->active_nodes);
183
184 write_unlock(&cache->active_lock);
David Howellsfee096d2009-11-19 18:12:05 +0000185 _leave(" = 0");
186 return 0;
David Howells9ae326a2009-04-03 16:42:41 +0100187
188 /* an old object from a previous incarnation is hogging the slot - we
189 * need to wait for it to be destroyed */
190wait_for_old_object:
David Howellsa30efe22014-09-30 14:50:30 +0100191 if (fscache_object_is_live(&xobject->fscache)) {
Fabian Frederick4e1eb882014-06-06 14:37:32 -0700192 pr_err("\n");
Fabian Frederick0227d6ab2014-06-06 14:37:33 -0700193 pr_err("Error: Unexpected object collision\n");
David Howellsd0e27b72009-11-19 18:12:02 +0000194 cachefiles_printk_object(object, xobject);
David Howells9ae326a2009-04-03 16:42:41 +0100195 BUG();
196 }
197 atomic_inc(&xobject->usage);
198 write_unlock(&cache->active_lock);
199
David Howellsfee096d2009-11-19 18:12:05 +0000200 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
201 wait_queue_head_t *wq;
202
203 signed long timeout = 60 * HZ;
204 wait_queue_t wait;
205 bool requeue;
206
207 /* if the object we're waiting for is queued for processing,
208 * then just put ourselves on the queue behind it */
Tejun Heo8b8edef2010-07-20 22:09:01 +0200209 if (work_pending(&xobject->fscache.work)) {
David Howellsfee096d2009-11-19 18:12:05 +0000210 _debug("queue OBJ%x behind OBJ%x immediately",
211 object->fscache.debug_id,
212 xobject->fscache.debug_id);
213 goto requeue;
214 }
215
216 /* otherwise we sleep until either the object we're waiting for
Tejun Heo8b8edef2010-07-20 22:09:01 +0200217 * is done, or the fscache_object is congested */
David Howellsfee096d2009-11-19 18:12:05 +0000218 wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
219 init_wait(&wait);
220 requeue = false;
221 do {
222 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
223 if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
224 break;
Tejun Heo8b8edef2010-07-20 22:09:01 +0200225
226 requeue = fscache_object_sleep_till_congested(&timeout);
David Howellsfee096d2009-11-19 18:12:05 +0000227 } while (timeout > 0 && !requeue);
228 finish_wait(wq, &wait);
229
230 if (requeue &&
231 test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags)) {
232 _debug("queue OBJ%x behind OBJ%x after wait",
233 object->fscache.debug_id,
234 xobject->fscache.debug_id);
235 goto requeue;
236 }
237
238 if (timeout <= 0) {
Fabian Frederick4e1eb882014-06-06 14:37:32 -0700239 pr_err("\n");
Fabian Frederick0227d6ab2014-06-06 14:37:33 -0700240 pr_err("Error: Overlong wait for old active object to go away\n");
David Howellsfee096d2009-11-19 18:12:05 +0000241 cachefiles_printk_object(object, xobject);
242 goto requeue;
243 }
244 }
245
246 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags));
David Howells9ae326a2009-04-03 16:42:41 +0100247
248 cache->cache.ops->put_object(&xobject->fscache);
249 goto try_again;
David Howellsfee096d2009-11-19 18:12:05 +0000250
251requeue:
252 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
253 cache->cache.ops->put_object(&xobject->fscache);
254 _leave(" = -ETIMEDOUT");
255 return -ETIMEDOUT;
David Howells9ae326a2009-04-03 16:42:41 +0100256}
257
258/*
259 * delete an object representation from the cache
260 * - file backed objects are unlinked
261 * - directory backed objects are stuffed into the graveyard for userspace to
262 * delete
263 * - unlocks the directory mutex
264 */
265static int cachefiles_bury_object(struct cachefiles_cache *cache,
266 struct dentry *dir,
David Howellsc61ea312010-05-11 16:51:39 +0100267 struct dentry *rep,
268 bool preemptive)
David Howells9ae326a2009-04-03 16:42:41 +0100269{
270 struct dentry *grave, *trap;
David Howells82140442010-12-24 14:48:35 +0000271 struct path path, path_to_graveyard;
David Howells9ae326a2009-04-03 16:42:41 +0100272 char nbuffer[8 + 8 + 1];
273 int ret;
274
Al Viroa4555892014-10-21 20:11:25 -0400275 _enter(",'%pd','%pd'", dir, rep);
David Howells9ae326a2009-04-03 16:42:41 +0100276
David Howellsc61ea312010-05-11 16:51:39 +0100277 _debug("remove %p from %p", rep, dir);
278
David Howells9ae326a2009-04-03 16:42:41 +0100279 /* non-directories can just be unlinked */
David Howellse36cb0b2015-01-29 12:02:35 +0000280 if (!d_is_dir(rep)) {
David Howells9ae326a2009-04-03 16:42:41 +0100281 _debug("unlink stale object");
David Howells9ae326a2009-04-03 16:42:41 +0100282
David Howells82140442010-12-24 14:48:35 +0000283 path.mnt = cache->mnt;
284 path.dentry = dir;
285 ret = security_path_unlink(&path, rep);
286 if (ret < 0) {
287 cachefiles_io_error(cache, "Unlink security error");
288 } else {
David Howells5153bc82015-03-06 14:08:58 +0000289 ret = vfs_unlink(d_inode(dir), rep, NULL);
David Howells82140442010-12-24 14:48:35 +0000290
291 if (preemptive)
292 cachefiles_mark_object_buried(cache, rep);
293 }
David Howellsc61ea312010-05-11 16:51:39 +0100294
David Howells5153bc82015-03-06 14:08:58 +0000295 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100296
297 if (ret == -EIO)
298 cachefiles_io_error(cache, "Unlink failed");
299
300 _leave(" = %d", ret);
301 return ret;
302 }
303
304 /* directories have to be moved to the graveyard */
305 _debug("move stale object to graveyard");
David Howells5153bc82015-03-06 14:08:58 +0000306 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100307
308try_again:
309 /* first step is to make up a grave dentry in the graveyard */
310 sprintf(nbuffer, "%08x%08x",
311 (uint32_t) get_seconds(),
312 (uint32_t) atomic_inc_return(&cache->gravecounter));
313
314 /* do the multiway lock magic */
315 trap = lock_rename(cache->graveyard, dir);
316
317 /* do some checks before getting the grave dentry */
318 if (rep->d_parent != dir) {
319 /* the entry was probably culled when we dropped the parent dir
320 * lock */
321 unlock_rename(cache->graveyard, dir);
322 _leave(" = 0 [culled?]");
323 return 0;
324 }
325
David Howellsce40fa72015-01-29 12:02:36 +0000326 if (!d_can_lookup(cache->graveyard)) {
David Howells9ae326a2009-04-03 16:42:41 +0100327 unlock_rename(cache->graveyard, dir);
328 cachefiles_io_error(cache, "Graveyard no longer a directory");
329 return -EIO;
330 }
331
332 if (trap == rep) {
333 unlock_rename(cache->graveyard, dir);
334 cachefiles_io_error(cache, "May not make directory loop");
335 return -EIO;
336 }
337
338 if (d_mountpoint(rep)) {
339 unlock_rename(cache->graveyard, dir);
340 cachefiles_io_error(cache, "Mountpoint in cache");
341 return -EIO;
342 }
343
344 grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
345 if (IS_ERR(grave)) {
346 unlock_rename(cache->graveyard, dir);
347
348 if (PTR_ERR(grave) == -ENOMEM) {
349 _leave(" = -ENOMEM");
350 return -ENOMEM;
351 }
352
353 cachefiles_io_error(cache, "Lookup error %ld",
354 PTR_ERR(grave));
355 return -EIO;
356 }
357
David Howells466b77b2015-03-17 22:26:21 +0000358 if (d_is_positive(grave)) {
David Howells9ae326a2009-04-03 16:42:41 +0100359 unlock_rename(cache->graveyard, dir);
360 dput(grave);
361 grave = NULL;
362 cond_resched();
363 goto try_again;
364 }
365
366 if (d_mountpoint(grave)) {
367 unlock_rename(cache->graveyard, dir);
368 dput(grave);
369 cachefiles_io_error(cache, "Mountpoint in graveyard");
370 return -EIO;
371 }
372
373 /* target should not be an ancestor of source */
374 if (trap == grave) {
375 unlock_rename(cache->graveyard, dir);
376 dput(grave);
377 cachefiles_io_error(cache, "May not make directory loop");
378 return -EIO;
379 }
380
381 /* attempt the rename */
David Howells82140442010-12-24 14:48:35 +0000382 path.mnt = cache->mnt;
383 path.dentry = dir;
384 path_to_graveyard.mnt = cache->mnt;
385 path_to_graveyard.dentry = cache->graveyard;
Miklos Szeredi0b3974e2014-04-01 17:08:43 +0200386 ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
David Howells82140442010-12-24 14:48:35 +0000387 if (ret < 0) {
388 cachefiles_io_error(cache, "Rename security error %d", ret);
389 } else {
David Howells5153bc82015-03-06 14:08:58 +0000390 ret = vfs_rename(d_inode(dir), rep,
391 d_inode(cache->graveyard), grave, NULL, 0);
David Howells82140442010-12-24 14:48:35 +0000392 if (ret != 0 && ret != -ENOMEM)
393 cachefiles_io_error(cache,
394 "Rename failed with error %d", ret);
David Howells9ae326a2009-04-03 16:42:41 +0100395
David Howells82140442010-12-24 14:48:35 +0000396 if (preemptive)
397 cachefiles_mark_object_buried(cache, rep);
398 }
David Howellsc61ea312010-05-11 16:51:39 +0100399
David Howells9ae326a2009-04-03 16:42:41 +0100400 unlock_rename(cache->graveyard, dir);
401 dput(grave);
402 _leave(" = 0");
403 return 0;
404}
405
406/*
407 * delete an object representation from the cache
408 */
409int cachefiles_delete_object(struct cachefiles_cache *cache,
410 struct cachefiles_object *object)
411{
412 struct dentry *dir;
413 int ret;
414
David Howellsc61ea312010-05-11 16:51:39 +0100415 _enter(",OBJ%x{%p}", object->fscache.debug_id, object->dentry);
David Howells9ae326a2009-04-03 16:42:41 +0100416
417 ASSERT(object->dentry);
David Howells466b77b2015-03-17 22:26:21 +0000418 ASSERT(d_backing_inode(object->dentry));
David Howells9ae326a2009-04-03 16:42:41 +0100419 ASSERT(object->dentry->d_parent);
420
421 dir = dget_parent(object->dentry);
422
David Howells5153bc82015-03-06 14:08:58 +0000423 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
David Howells8f9941a2010-02-19 18:14:21 +0000424
David Howellsc61ea312010-05-11 16:51:39 +0100425 if (test_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
426 /* object allocation for the same key preemptively deleted this
427 * object's file so that it could create its own file */
428 _debug("object preemptively buried");
David Howells5153bc82015-03-06 14:08:58 +0000429 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells8f9941a2010-02-19 18:14:21 +0000430 ret = 0;
David Howellsc61ea312010-05-11 16:51:39 +0100431 } else {
432 /* we need to check that our parent is _still_ our parent - it
433 * may have been renamed */
434 if (dir == object->dentry->d_parent) {
435 ret = cachefiles_bury_object(cache, dir,
436 object->dentry, false);
437 } else {
438 /* it got moved, presumably by cachefilesd culling it,
439 * so it's no longer in the key path and we can ignore
440 * it */
David Howells5153bc82015-03-06 14:08:58 +0000441 mutex_unlock(&d_inode(dir)->i_mutex);
David Howellsc61ea312010-05-11 16:51:39 +0100442 ret = 0;
443 }
David Howells8f9941a2010-02-19 18:14:21 +0000444 }
David Howells9ae326a2009-04-03 16:42:41 +0100445
446 dput(dir);
447 _leave(" = %d", ret);
448 return ret;
449}
450
451/*
452 * walk from the parent object to the child object through the backing
453 * filesystem, creating directories as we go
454 */
455int cachefiles_walk_to_object(struct cachefiles_object *parent,
456 struct cachefiles_object *object,
457 const char *key,
458 struct cachefiles_xattr *auxdata)
459{
460 struct cachefiles_cache *cache;
461 struct dentry *dir, *next = NULL;
David Howells82140442010-12-24 14:48:35 +0000462 struct path path;
David Howells9ae326a2009-04-03 16:42:41 +0100463 unsigned long start;
464 const char *name;
465 int ret, nlen;
466
David Howellsc61ea312010-05-11 16:51:39 +0100467 _enter("OBJ%x{%p},OBJ%x,%s,",
468 parent->fscache.debug_id, parent->dentry,
469 object->fscache.debug_id, key);
David Howells9ae326a2009-04-03 16:42:41 +0100470
471 cache = container_of(parent->fscache.cache,
472 struct cachefiles_cache, cache);
David Howells82140442010-12-24 14:48:35 +0000473 path.mnt = cache->mnt;
David Howells9ae326a2009-04-03 16:42:41 +0100474
475 ASSERT(parent->dentry);
David Howells466b77b2015-03-17 22:26:21 +0000476 ASSERT(d_backing_inode(parent->dentry));
David Howells9ae326a2009-04-03 16:42:41 +0100477
David Howellse36cb0b2015-01-29 12:02:35 +0000478 if (!(d_is_dir(parent->dentry))) {
David Howells9ae326a2009-04-03 16:42:41 +0100479 // TODO: convert file to dir
480 _leave("looking up in none directory");
481 return -ENOBUFS;
482 }
483
484 dir = dget(parent->dentry);
485
486advance:
487 /* attempt to transit the first directory component */
488 name = key;
489 nlen = strlen(key);
490
491 /* key ends in a double NUL */
492 key = key + nlen + 1;
493 if (!*key)
494 key = NULL;
495
496lookup_again:
497 /* search the current directory for the element name */
498 _debug("lookup '%s'", name);
499
David Howells5153bc82015-03-06 14:08:58 +0000500 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
David Howells9ae326a2009-04-03 16:42:41 +0100501
502 start = jiffies;
503 next = lookup_one_len(name, dir, nlen);
504 cachefiles_hist(cachefiles_lookup_histogram, start);
505 if (IS_ERR(next))
506 goto lookup_error;
507
David Howells466b77b2015-03-17 22:26:21 +0000508 _debug("next -> %p %s", next, d_backing_inode(next) ? "positive" : "negative");
David Howells9ae326a2009-04-03 16:42:41 +0100509
510 if (!key)
David Howells466b77b2015-03-17 22:26:21 +0000511 object->new = !d_backing_inode(next);
David Howells9ae326a2009-04-03 16:42:41 +0100512
513 /* if this element of the path doesn't exist, then the lookup phase
514 * failed, and we can release any readers in the certain knowledge that
515 * there's nothing for them to actually read */
David Howells466b77b2015-03-17 22:26:21 +0000516 if (d_is_negative(next))
David Howells9ae326a2009-04-03 16:42:41 +0100517 fscache_object_lookup_negative(&object->fscache);
518
519 /* we need to create the object if it's negative */
520 if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) {
521 /* index objects and intervening tree levels must be subdirs */
David Howells466b77b2015-03-17 22:26:21 +0000522 if (d_is_negative(next)) {
David Howells9ae326a2009-04-03 16:42:41 +0100523 ret = cachefiles_has_space(cache, 1, 0);
524 if (ret < 0)
525 goto create_error;
526
David Howells82140442010-12-24 14:48:35 +0000527 path.dentry = dir;
528 ret = security_path_mkdir(&path, next, 0);
529 if (ret < 0)
530 goto create_error;
David Howells9ae326a2009-04-03 16:42:41 +0100531 start = jiffies;
David Howells5153bc82015-03-06 14:08:58 +0000532 ret = vfs_mkdir(d_inode(dir), next, 0);
David Howells9ae326a2009-04-03 16:42:41 +0100533 cachefiles_hist(cachefiles_mkdir_histogram, start);
534 if (ret < 0)
535 goto create_error;
536
David Howells466b77b2015-03-17 22:26:21 +0000537 ASSERT(d_backing_inode(next));
David Howells9ae326a2009-04-03 16:42:41 +0100538
539 _debug("mkdir -> %p{%p{ino=%lu}}",
David Howells466b77b2015-03-17 22:26:21 +0000540 next, d_backing_inode(next), d_backing_inode(next)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100541
David Howellsce40fa72015-01-29 12:02:36 +0000542 } else if (!d_can_lookup(next)) {
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700543 pr_err("inode %lu is not a directory\n",
David Howells466b77b2015-03-17 22:26:21 +0000544 d_backing_inode(next)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100545 ret = -ENOBUFS;
546 goto error;
547 }
548
549 } else {
550 /* non-index objects start out life as files */
David Howells466b77b2015-03-17 22:26:21 +0000551 if (d_is_negative(next)) {
David Howells9ae326a2009-04-03 16:42:41 +0100552 ret = cachefiles_has_space(cache, 1, 0);
553 if (ret < 0)
554 goto create_error;
555
David Howells82140442010-12-24 14:48:35 +0000556 path.dentry = dir;
557 ret = security_path_mknod(&path, next, S_IFREG, 0);
558 if (ret < 0)
559 goto create_error;
David Howells9ae326a2009-04-03 16:42:41 +0100560 start = jiffies;
David Howells5153bc82015-03-06 14:08:58 +0000561 ret = vfs_create(d_inode(dir), next, S_IFREG, true);
David Howells9ae326a2009-04-03 16:42:41 +0100562 cachefiles_hist(cachefiles_create_histogram, start);
563 if (ret < 0)
564 goto create_error;
565
David Howells466b77b2015-03-17 22:26:21 +0000566 ASSERT(d_backing_inode(next));
David Howells9ae326a2009-04-03 16:42:41 +0100567
568 _debug("create -> %p{%p{ino=%lu}}",
David Howells466b77b2015-03-17 22:26:21 +0000569 next, d_backing_inode(next), d_backing_inode(next)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100570
David Howellsce40fa72015-01-29 12:02:36 +0000571 } else if (!d_can_lookup(next) &&
David Howellse36cb0b2015-01-29 12:02:35 +0000572 !d_is_reg(next)
David Howells9ae326a2009-04-03 16:42:41 +0100573 ) {
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700574 pr_err("inode %lu is not a file or directory\n",
David Howells466b77b2015-03-17 22:26:21 +0000575 d_backing_inode(next)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100576 ret = -ENOBUFS;
577 goto error;
578 }
579 }
580
581 /* process the next component */
582 if (key) {
583 _debug("advance");
David Howells5153bc82015-03-06 14:08:58 +0000584 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100585 dput(dir);
586 dir = next;
587 next = NULL;
588 goto advance;
589 }
590
591 /* we've found the object we were looking for */
592 object->dentry = next;
593
594 /* if we've found that the terminal object exists, then we need to
595 * check its attributes and delete it if it's out of date */
596 if (!object->new) {
Al Viroa4555892014-10-21 20:11:25 -0400597 _debug("validate '%pd'", next);
David Howells9ae326a2009-04-03 16:42:41 +0100598
599 ret = cachefiles_check_object_xattr(object, auxdata);
600 if (ret == -ESTALE) {
601 /* delete the object (the deleter drops the directory
602 * mutex) */
603 object->dentry = NULL;
604
David Howellsc61ea312010-05-11 16:51:39 +0100605 ret = cachefiles_bury_object(cache, dir, next, true);
David Howells9ae326a2009-04-03 16:42:41 +0100606 dput(next);
607 next = NULL;
608
609 if (ret < 0)
610 goto delete_error;
611
612 _debug("redo lookup");
613 goto lookup_again;
614 }
615 }
616
617 /* note that we're now using this object */
David Howellsfee096d2009-11-19 18:12:05 +0000618 ret = cachefiles_mark_object_active(cache, object);
David Howells9ae326a2009-04-03 16:42:41 +0100619
David Howells5153bc82015-03-06 14:08:58 +0000620 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100621 dput(dir);
622 dir = NULL;
623
David Howellsfee096d2009-11-19 18:12:05 +0000624 if (ret == -ETIMEDOUT)
625 goto mark_active_timed_out;
626
David Howells9ae326a2009-04-03 16:42:41 +0100627 _debug("=== OBTAINED_OBJECT ===");
628
629 if (object->new) {
630 /* attach data to a newly constructed terminal object */
631 ret = cachefiles_set_object_xattr(object, auxdata);
632 if (ret < 0)
633 goto check_error;
634 } else {
635 /* always update the atime on an object we've just looked up
636 * (this is used to keep track of culling, and atimes are only
637 * updated by read, write and readdir but not lookup or
638 * open) */
Al Viro68ac1232012-03-15 08:21:57 -0400639 path.dentry = next;
640 touch_atime(&path);
David Howells9ae326a2009-04-03 16:42:41 +0100641 }
642
643 /* open a file interface onto a data file */
644 if (object->type != FSCACHE_COOKIE_TYPE_INDEX) {
David Howellse36cb0b2015-01-29 12:02:35 +0000645 if (d_is_reg(object->dentry)) {
David Howells9ae326a2009-04-03 16:42:41 +0100646 const struct address_space_operations *aops;
647
648 ret = -EPERM;
David Howells466b77b2015-03-17 22:26:21 +0000649 aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
David Howells9ae326a2009-04-03 16:42:41 +0100650 if (!aops->bmap)
651 goto check_error;
652
653 object->backer = object->dentry;
654 } else {
655 BUG(); // TODO: open file in data-class subdir
656 }
657 }
658
659 object->new = 0;
660 fscache_obtained_object(&object->fscache);
661
David Howells466b77b2015-03-17 22:26:21 +0000662 _leave(" = 0 [%lu]", d_backing_inode(object->dentry)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100663 return 0;
664
665create_error:
666 _debug("create error %d", ret);
667 if (ret == -EIO)
668 cachefiles_io_error(cache, "Create/mkdir failed");
669 goto error;
670
David Howellsfee096d2009-11-19 18:12:05 +0000671mark_active_timed_out:
672 _debug("mark active timed out");
673 goto release_dentry;
674
David Howells9ae326a2009-04-03 16:42:41 +0100675check_error:
676 _debug("check error %d", ret);
677 write_lock(&cache->active_lock);
678 rb_erase(&object->active_node, &cache->active_nodes);
679 clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
680 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
681 write_unlock(&cache->active_lock);
David Howellsfee096d2009-11-19 18:12:05 +0000682release_dentry:
David Howells9ae326a2009-04-03 16:42:41 +0100683 dput(object->dentry);
684 object->dentry = NULL;
685 goto error_out;
686
687delete_error:
688 _debug("delete error %d", ret);
689 goto error_out2;
690
691lookup_error:
692 _debug("lookup error %ld", PTR_ERR(next));
693 ret = PTR_ERR(next);
694 if (ret == -EIO)
695 cachefiles_io_error(cache, "Lookup failed");
696 next = NULL;
697error:
David Howells5153bc82015-03-06 14:08:58 +0000698 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100699 dput(next);
700error_out2:
701 dput(dir);
702error_out:
David Howells9ae326a2009-04-03 16:42:41 +0100703 _leave(" = error %d", -ret);
704 return ret;
705}
706
707/*
708 * get a subdirectory
709 */
710struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
711 struct dentry *dir,
712 const char *dirname)
713{
714 struct dentry *subdir;
715 unsigned long start;
David Howells82140442010-12-24 14:48:35 +0000716 struct path path;
David Howells9ae326a2009-04-03 16:42:41 +0100717 int ret;
718
719 _enter(",,%s", dirname);
720
721 /* search the current directory for the element name */
David Howells5153bc82015-03-06 14:08:58 +0000722 mutex_lock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100723
724 start = jiffies;
725 subdir = lookup_one_len(dirname, dir, strlen(dirname));
726 cachefiles_hist(cachefiles_lookup_histogram, start);
727 if (IS_ERR(subdir)) {
728 if (PTR_ERR(subdir) == -ENOMEM)
729 goto nomem_d_alloc;
730 goto lookup_error;
731 }
732
733 _debug("subdir -> %p %s",
David Howells466b77b2015-03-17 22:26:21 +0000734 subdir, d_backing_inode(subdir) ? "positive" : "negative");
David Howells9ae326a2009-04-03 16:42:41 +0100735
736 /* we need to create the subdir if it doesn't exist yet */
David Howells466b77b2015-03-17 22:26:21 +0000737 if (d_is_negative(subdir)) {
David Howells9ae326a2009-04-03 16:42:41 +0100738 ret = cachefiles_has_space(cache, 1, 0);
739 if (ret < 0)
740 goto mkdir_error;
741
742 _debug("attempt mkdir");
743
David Howells82140442010-12-24 14:48:35 +0000744 path.mnt = cache->mnt;
745 path.dentry = dir;
746 ret = security_path_mkdir(&path, subdir, 0700);
747 if (ret < 0)
748 goto mkdir_error;
David Howells5153bc82015-03-06 14:08:58 +0000749 ret = vfs_mkdir(d_inode(dir), subdir, 0700);
David Howells9ae326a2009-04-03 16:42:41 +0100750 if (ret < 0)
751 goto mkdir_error;
752
David Howells466b77b2015-03-17 22:26:21 +0000753 ASSERT(d_backing_inode(subdir));
David Howells9ae326a2009-04-03 16:42:41 +0100754
755 _debug("mkdir -> %p{%p{ino=%lu}}",
756 subdir,
David Howells466b77b2015-03-17 22:26:21 +0000757 d_backing_inode(subdir),
758 d_backing_inode(subdir)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100759 }
760
David Howells5153bc82015-03-06 14:08:58 +0000761 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100762
763 /* we need to make sure the subdir is a directory */
David Howells466b77b2015-03-17 22:26:21 +0000764 ASSERT(d_backing_inode(subdir));
David Howells9ae326a2009-04-03 16:42:41 +0100765
David Howellsce40fa72015-01-29 12:02:36 +0000766 if (!d_can_lookup(subdir)) {
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700767 pr_err("%s is not a directory\n", dirname);
David Howells9ae326a2009-04-03 16:42:41 +0100768 ret = -EIO;
769 goto check_error;
770 }
771
772 ret = -EPERM;
David Howells466b77b2015-03-17 22:26:21 +0000773 if (!d_backing_inode(subdir)->i_op->setxattr ||
774 !d_backing_inode(subdir)->i_op->getxattr ||
775 !d_backing_inode(subdir)->i_op->lookup ||
776 !d_backing_inode(subdir)->i_op->mkdir ||
777 !d_backing_inode(subdir)->i_op->create ||
778 (!d_backing_inode(subdir)->i_op->rename &&
779 !d_backing_inode(subdir)->i_op->rename2) ||
780 !d_backing_inode(subdir)->i_op->rmdir ||
781 !d_backing_inode(subdir)->i_op->unlink)
David Howells9ae326a2009-04-03 16:42:41 +0100782 goto check_error;
783
David Howells466b77b2015-03-17 22:26:21 +0000784 _leave(" = [%lu]", d_backing_inode(subdir)->i_ino);
David Howells9ae326a2009-04-03 16:42:41 +0100785 return subdir;
786
787check_error:
788 dput(subdir);
789 _leave(" = %d [check]", ret);
790 return ERR_PTR(ret);
791
792mkdir_error:
David Howells5153bc82015-03-06 14:08:58 +0000793 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100794 dput(subdir);
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700795 pr_err("mkdir %s failed with error %d\n", dirname, ret);
David Howells9ae326a2009-04-03 16:42:41 +0100796 return ERR_PTR(ret);
797
798lookup_error:
David Howells5153bc82015-03-06 14:08:58 +0000799 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100800 ret = PTR_ERR(subdir);
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700801 pr_err("Lookup %s failed with error %d\n", dirname, ret);
David Howells9ae326a2009-04-03 16:42:41 +0100802 return ERR_PTR(ret);
803
804nomem_d_alloc:
David Howells5153bc82015-03-06 14:08:58 +0000805 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100806 _leave(" = -ENOMEM");
807 return ERR_PTR(-ENOMEM);
808}
809
810/*
811 * find out if an object is in use or not
812 * - if finds object and it's not in use:
813 * - returns a pointer to the object and a reference on it
814 * - returns with the directory locked
815 */
816static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
817 struct dentry *dir,
818 char *filename)
819{
820 struct cachefiles_object *object;
821 struct rb_node *_n;
822 struct dentry *victim;
823 unsigned long start;
824 int ret;
825
Al Viroa4555892014-10-21 20:11:25 -0400826 //_enter(",%pd/,%s",
827 // dir, filename);
David Howells9ae326a2009-04-03 16:42:41 +0100828
829 /* look up the victim */
David Howells5153bc82015-03-06 14:08:58 +0000830 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
David Howells9ae326a2009-04-03 16:42:41 +0100831
832 start = jiffies;
833 victim = lookup_one_len(filename, dir, strlen(filename));
834 cachefiles_hist(cachefiles_lookup_histogram, start);
835 if (IS_ERR(victim))
836 goto lookup_error;
837
838 //_debug("victim -> %p %s",
David Howells466b77b2015-03-17 22:26:21 +0000839 // victim, d_backing_inode(victim) ? "positive" : "negative");
David Howells9ae326a2009-04-03 16:42:41 +0100840
841 /* if the object is no longer there then we probably retired the object
842 * at the netfs's request whilst the cull was in progress
843 */
David Howells466b77b2015-03-17 22:26:21 +0000844 if (d_is_negative(victim)) {
David Howells5153bc82015-03-06 14:08:58 +0000845 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100846 dput(victim);
847 _leave(" = -ENOENT [absent]");
848 return ERR_PTR(-ENOENT);
849 }
850
851 /* check to see if we're using this object */
852 read_lock(&cache->active_lock);
853
854 _n = cache->active_nodes.rb_node;
855
856 while (_n) {
857 object = rb_entry(_n, struct cachefiles_object, active_node);
858
859 if (object->dentry > victim)
860 _n = _n->rb_left;
861 else if (object->dentry < victim)
862 _n = _n->rb_right;
863 else
864 goto object_in_use;
865 }
866
867 read_unlock(&cache->active_lock);
868
869 //_leave(" = %p", victim);
870 return victim;
871
872object_in_use:
873 read_unlock(&cache->active_lock);
David Howells5153bc82015-03-06 14:08:58 +0000874 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100875 dput(victim);
876 //_leave(" = -EBUSY [in use]");
877 return ERR_PTR(-EBUSY);
878
879lookup_error:
David Howells5153bc82015-03-06 14:08:58 +0000880 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100881 ret = PTR_ERR(victim);
882 if (ret == -ENOENT) {
883 /* file or dir now absent - probably retired by netfs */
884 _leave(" = -ESTALE [absent]");
885 return ERR_PTR(-ESTALE);
886 }
887
888 if (ret == -EIO) {
889 cachefiles_io_error(cache, "Lookup failed");
890 } else if (ret != -ENOMEM) {
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700891 pr_err("Internal error: %d\n", ret);
David Howells9ae326a2009-04-03 16:42:41 +0100892 ret = -EIO;
893 }
894
895 _leave(" = %d", ret);
896 return ERR_PTR(ret);
897}
898
899/*
900 * cull an object if it's not in use
901 * - called only by cache manager daemon
902 */
903int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
904 char *filename)
905{
906 struct dentry *victim;
907 int ret;
908
Al Viroa4555892014-10-21 20:11:25 -0400909 _enter(",%pd/,%s", dir, filename);
David Howells9ae326a2009-04-03 16:42:41 +0100910
911 victim = cachefiles_check_active(cache, dir, filename);
912 if (IS_ERR(victim))
913 return PTR_ERR(victim);
914
915 _debug("victim -> %p %s",
David Howells466b77b2015-03-17 22:26:21 +0000916 victim, d_backing_inode(victim) ? "positive" : "negative");
David Howells9ae326a2009-04-03 16:42:41 +0100917
918 /* okay... the victim is not being used so we can cull it
919 * - start by marking it as stale
920 */
921 _debug("victim is cullable");
922
923 ret = cachefiles_remove_object_xattr(cache, victim);
924 if (ret < 0)
925 goto error_unlock;
926
927 /* actually remove the victim (drops the dir mutex) */
928 _debug("bury");
929
David Howellsc61ea312010-05-11 16:51:39 +0100930 ret = cachefiles_bury_object(cache, dir, victim, false);
David Howells9ae326a2009-04-03 16:42:41 +0100931 if (ret < 0)
932 goto error;
933
934 dput(victim);
935 _leave(" = 0");
936 return 0;
937
938error_unlock:
David Howells5153bc82015-03-06 14:08:58 +0000939 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100940error:
941 dput(victim);
942 if (ret == -ENOENT) {
943 /* file or dir now absent - probably retired by netfs */
944 _leave(" = -ESTALE [absent]");
945 return -ESTALE;
946 }
947
948 if (ret != -ENOMEM) {
Fabian Frederick6ff66ac2014-09-25 16:05:27 -0700949 pr_err("Internal error: %d\n", ret);
David Howells9ae326a2009-04-03 16:42:41 +0100950 ret = -EIO;
951 }
952
953 _leave(" = %d", ret);
954 return ret;
955}
956
957/*
958 * find out if an object is in use or not
959 * - called only by cache manager daemon
960 * - returns -EBUSY or 0 to indicate whether an object is in use or not
961 */
962int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
963 char *filename)
964{
965 struct dentry *victim;
966
Al Viroa4555892014-10-21 20:11:25 -0400967 //_enter(",%pd/,%s",
968 // dir, filename);
David Howells9ae326a2009-04-03 16:42:41 +0100969
970 victim = cachefiles_check_active(cache, dir, filename);
971 if (IS_ERR(victim))
972 return PTR_ERR(victim);
973
David Howells5153bc82015-03-06 14:08:58 +0000974 mutex_unlock(&d_inode(dir)->i_mutex);
David Howells9ae326a2009-04-03 16:42:41 +0100975 dput(victim);
976 //_leave(" = 0");
977 return 0;
978}