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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* FS-Cache interface to CacheFiles
3 *
4 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/slab.h>
9#include <linux/mount.h>
10#include <linux/xattr.h>
11#include <linux/file.h>
12#include <linux/falloc.h>
13#include <trace/events/fscache.h>
14#include "internal.h"
15
16static atomic_t cachefiles_object_debug_id;
17
18/*
19 * Allocate a cache object record.
20 */
21static
22struct cachefiles_object *cachefiles_alloc_object(struct fscache_cookie *cookie)
23{
24 struct fscache_volume *vcookie = cookie->volume;
25 struct cachefiles_volume *volume = vcookie->cache_priv;
26 struct cachefiles_object *object;
27
28 _enter("{%s},%x,", vcookie->key, cookie->debug_id);
29
30 object = kmem_cache_zalloc(cachefiles_object_jar, GFP_KERNEL);
31 if (!object)
32 return NULL;
33
34 if (cachefiles_ondemand_init_obj_info(object, volume)) {
35 kmem_cache_free(cachefiles_object_jar, object);
36 return NULL;
37 }
38
39 refcount_set(&object->ref, 1);
40
41 spin_lock_init(&object->lock);
42 INIT_LIST_HEAD(&object->cache_link);
43 object->volume = volume;
44 object->debug_id = atomic_inc_return(&cachefiles_object_debug_id);
45 object->cookie = fscache_get_cookie(cookie, fscache_cookie_get_attach_object);
46
47 fscache_count_object(vcookie->cache);
48 trace_cachefiles_ref(object->debug_id, cookie->debug_id, 1,
49 cachefiles_obj_new);
50 return object;
51}
52
53/*
54 * Note that an object has been seen.
55 */
56void cachefiles_see_object(struct cachefiles_object *object,
57 enum cachefiles_obj_ref_trace why)
58{
59 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id,
60 refcount_read(&object->ref), why);
61}
62
63/*
64 * Increment the usage count on an object;
65 */
66struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
67 enum cachefiles_obj_ref_trace why)
68{
69 int r;
70
71 __refcount_inc(&object->ref, &r);
72 trace_cachefiles_ref(object->debug_id, object->cookie->debug_id, r, why);
73 return object;
74}
75
76/*
77 * dispose of a reference to an object
78 */
79void cachefiles_put_object(struct cachefiles_object *object,
80 enum cachefiles_obj_ref_trace why)
81{
82 unsigned int object_debug_id = object->debug_id;
83 unsigned int cookie_debug_id = object->cookie->debug_id;
84 struct fscache_cache *cache;
85 bool done;
86 int r;
87
88 done = __refcount_dec_and_test(&object->ref, &r);
89 trace_cachefiles_ref(object_debug_id, cookie_debug_id, r, why);
90 if (done) {
91 _debug("- kill object OBJ%x", object_debug_id);
92
93 ASSERTCMP(object->file, ==, NULL);
94
95 kfree(object->d_name);
96 cachefiles_ondemand_deinit_obj_info(object);
97 cache = object->volume->cache->cache;
98 fscache_put_cookie(object->cookie, fscache_cookie_put_object);
99 object->cookie = NULL;
100 kmem_cache_free(cachefiles_object_jar, object);
101 fscache_uncount_object(cache);
102 }
103
104 _leave("");
105}
106
107/*
108 * Adjust the size of a cache file if necessary to match the DIO size. We keep
109 * the EOF marker a multiple of DIO blocks so that we don't fall back to doing
110 * non-DIO for a partial block straddling the EOF, but we also have to be
111 * careful of someone expanding the file and accidentally accreting the
112 * padding.
113 */
114static int cachefiles_adjust_size(struct cachefiles_object *object)
115{
116 struct iattr newattrs;
117 struct file *file = object->file;
118 uint64_t ni_size;
119 loff_t oi_size;
120 int ret;
121
122 ni_size = object->cookie->object_size;
123 ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
124
125 _enter("{OBJ%x},[%llu]",
126 object->debug_id, (unsigned long long) ni_size);
127
128 if (!file)
129 return -ENOBUFS;
130
131 oi_size = i_size_read(file_inode(file));
132 if (oi_size == ni_size)
133 return 0;
134
135 inode_lock(file_inode(file));
136
137 /* if there's an extension to a partial page at the end of the backing
138 * file, we need to discard the partial page so that we pick up new
139 * data after it */
140 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
141 _debug("discard tail %llx", oi_size);
142 newattrs.ia_valid = ATTR_SIZE;
143 newattrs.ia_size = oi_size & PAGE_MASK;
144 ret = cachefiles_inject_remove_error();
145 if (ret == 0)
146 ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
147 &newattrs, NULL);
148 if (ret < 0)
149 goto truncate_failed;
150 }
151
152 newattrs.ia_valid = ATTR_SIZE;
153 newattrs.ia_size = ni_size;
154 ret = cachefiles_inject_write_error();
155 if (ret == 0)
156 ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
157 &newattrs, NULL);
158
159truncate_failed:
160 inode_unlock(file_inode(file));
161
162 if (ret < 0)
163 trace_cachefiles_io_error(NULL, file_inode(file), ret,
164 cachefiles_trace_notify_change_error);
165 if (ret == -EIO) {
166 cachefiles_io_error_obj(object, "Size set failed");
167 ret = -ENOBUFS;
168 }
169
170 _leave(" = %d", ret);
171 return ret;
172}
173
174/*
175 * Attempt to look up the nominated node in this cache
176 */
177static bool cachefiles_lookup_cookie(struct fscache_cookie *cookie)
178{
179 struct cachefiles_object *object;
180 struct cachefiles_cache *cache = cookie->volume->cache->cache_priv;
181 const struct cred *saved_cred;
182 bool success;
183
184 object = cachefiles_alloc_object(cookie);
185 if (!object)
186 goto fail;
187
188 _enter("{OBJ%x}", object->debug_id);
189
190 if (!cachefiles_cook_key(object))
191 goto fail_put;
192
193 cookie->cache_priv = object;
194
195 cachefiles_begin_secure(cache, &saved_cred);
196
197 success = cachefiles_look_up_object(object);
198 if (!success)
199 goto fail_withdraw;
200
201 cachefiles_see_object(object, cachefiles_obj_see_lookup_cookie);
202
203 spin_lock(&cache->object_list_lock);
204 list_add(&object->cache_link, &cache->object_list);
205 spin_unlock(&cache->object_list_lock);
206 cachefiles_adjust_size(object);
207
208 cachefiles_end_secure(cache, saved_cred);
209 _leave(" = t");
210 return true;
211
212fail_withdraw:
213 cachefiles_end_secure(cache, saved_cred);
214 cachefiles_see_object(object, cachefiles_obj_see_lookup_failed);
215 fscache_caching_failed(cookie);
216 _debug("failed c=%08x o=%08x", cookie->debug_id, object->debug_id);
217 /* The caller holds an access count on the cookie, so we need them to
218 * drop it before we can withdraw the object.
219 */
220 return false;
221
222fail_put:
223 cachefiles_put_object(object, cachefiles_obj_put_alloc_fail);
224fail:
225 return false;
226}
227
228/*
229 * Shorten the backing object to discard any dirty data and free up
230 * any unused granules.
231 */
232static bool cachefiles_shorten_object(struct cachefiles_object *object,
233 struct file *file, loff_t new_size)
234{
235 struct cachefiles_cache *cache = object->volume->cache;
236 struct inode *inode = file_inode(file);
237 loff_t i_size, dio_size;
238 int ret;
239
240 dio_size = round_up(new_size, CACHEFILES_DIO_BLOCK_SIZE);
241 i_size = i_size_read(inode);
242
243 trace_cachefiles_trunc(object, inode, i_size, dio_size,
244 cachefiles_trunc_shrink);
245 ret = cachefiles_inject_remove_error();
246 if (ret == 0)
247 ret = vfs_truncate(&file->f_path, dio_size);
248 if (ret < 0) {
249 trace_cachefiles_io_error(object, file_inode(file), ret,
250 cachefiles_trace_trunc_error);
251 cachefiles_io_error_obj(object, "Trunc-to-size failed %d", ret);
252 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
253 return false;
254 }
255
256 if (new_size < dio_size) {
257 trace_cachefiles_trunc(object, inode, dio_size, new_size,
258 cachefiles_trunc_dio_adjust);
259 ret = cachefiles_inject_write_error();
260 if (ret == 0)
261 ret = vfs_fallocate(file, FALLOC_FL_ZERO_RANGE,
262 new_size, dio_size - new_size);
263 if (ret < 0) {
264 trace_cachefiles_io_error(object, file_inode(file), ret,
265 cachefiles_trace_fallocate_error);
266 cachefiles_io_error_obj(object, "Trunc-to-dio-size failed %d", ret);
267 cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
268 return false;
269 }
270 }
271
272 return true;
273}
274
275/*
276 * Resize the backing object.
277 */
278static void cachefiles_resize_cookie(struct netfs_cache_resources *cres,
279 loff_t new_size)
280{
281 struct cachefiles_object *object = cachefiles_cres_object(cres);
282 struct cachefiles_cache *cache = object->volume->cache;
283 struct fscache_cookie *cookie = object->cookie;
284 const struct cred *saved_cred;
285 struct file *file = cachefiles_cres_file(cres);
286 loff_t old_size = cookie->object_size;
287
288 _enter("%llu->%llu", old_size, new_size);
289
290 if (new_size < old_size) {
291 cachefiles_begin_secure(cache, &saved_cred);
292 cachefiles_shorten_object(object, file, new_size);
293 cachefiles_end_secure(cache, saved_cred);
294 object->cookie->object_size = new_size;
295 return;
296 }
297
298 /* The file is being expanded. We don't need to do anything
299 * particularly. cookie->initial_size doesn't change and so the point
300 * at which we have to download before doesn't change.
301 */
302 cookie->object_size = new_size;
303}
304
305/*
306 * Commit changes to the object as we drop it.
307 */
308static void cachefiles_commit_object(struct cachefiles_object *object,
309 struct cachefiles_cache *cache)
310{
311 bool update = false;
312
313 if (test_and_clear_bit(FSCACHE_COOKIE_LOCAL_WRITE, &object->cookie->flags))
314 update = true;
315 if (test_and_clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags))
316 update = true;
317 if (update)
318 cachefiles_set_object_xattr(object);
319
320 if (test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags))
321 cachefiles_commit_tmpfile(cache, object);
322}
323
324/*
325 * Finalise and object and close the VFS structs that we have.
326 */
327static void cachefiles_clean_up_object(struct cachefiles_object *object,
328 struct cachefiles_cache *cache)
329{
330 if (test_bit(FSCACHE_COOKIE_RETIRED, &object->cookie->flags)) {
331 if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
332 cachefiles_see_object(object, cachefiles_obj_see_clean_delete);
333 _debug("- inval object OBJ%x", object->debug_id);
334 cachefiles_delete_object(object, FSCACHE_OBJECT_WAS_RETIRED);
335 } else {
336 cachefiles_see_object(object, cachefiles_obj_see_clean_drop_tmp);
337 _debug("- inval object OBJ%x tmpfile", object->debug_id);
338 }
339 } else {
340 cachefiles_see_object(object, cachefiles_obj_see_clean_commit);
341 cachefiles_commit_object(object, cache);
342 }
343
344 cachefiles_unmark_inode_in_use(object, object->file);
345 if (object->file) {
346 fput(object->file);
347 object->file = NULL;
348 }
349}
350
351/*
352 * Withdraw caching for a cookie.
353 */
354static void cachefiles_withdraw_cookie(struct fscache_cookie *cookie)
355{
356 struct cachefiles_object *object = cookie->cache_priv;
357 struct cachefiles_cache *cache = object->volume->cache;
358 const struct cred *saved_cred;
359
360 _enter("o=%x", object->debug_id);
361 cachefiles_see_object(object, cachefiles_obj_see_withdraw_cookie);
362
363 if (!list_empty(&object->cache_link)) {
364 spin_lock(&cache->object_list_lock);
365 cachefiles_see_object(object, cachefiles_obj_see_withdrawal);
366 list_del_init(&object->cache_link);
367 spin_unlock(&cache->object_list_lock);
368 }
369
370 cachefiles_ondemand_clean_object(object);
371
372 if (object->file) {
373 cachefiles_begin_secure(cache, &saved_cred);
374 cachefiles_clean_up_object(object, cache);
375 cachefiles_end_secure(cache, saved_cred);
376 }
377
378 cookie->cache_priv = NULL;
379 cachefiles_put_object(object, cachefiles_obj_put_detach);
380}
381
382/*
383 * Invalidate the storage associated with a cookie.
384 */
385static bool cachefiles_invalidate_cookie(struct fscache_cookie *cookie)
386{
387 struct cachefiles_object *object = cookie->cache_priv;
388 struct file *new_file, *old_file;
389 bool old_tmpfile;
390
391 _enter("o=%x,[%llu]", object->debug_id, object->cookie->object_size);
392
393 old_tmpfile = test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
394
395 if (!object->file) {
396 fscache_resume_after_invalidation(cookie);
397 _leave(" = t [light]");
398 return true;
399 }
400
401 new_file = cachefiles_create_tmpfile(object);
402 if (IS_ERR(new_file))
403 goto failed;
404
405 /* Substitute the VFS target */
406 _debug("sub");
407 spin_lock(&object->lock);
408
409 old_file = object->file;
410 object->file = new_file;
411 object->content_info = CACHEFILES_CONTENT_NO_DATA;
412 set_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags);
413 set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &object->cookie->flags);
414
415 spin_unlock(&object->lock);
416 _debug("subbed");
417
418 /* Allow I/O to take place again */
419 fscache_resume_after_invalidation(cookie);
420
421 if (old_file) {
422 if (!old_tmpfile) {
423 struct cachefiles_volume *volume = object->volume;
424 struct dentry *fan = volume->fanout[(u8)cookie->key_hash];
425
426 inode_lock_nested(d_inode(fan), I_MUTEX_PARENT);
427 cachefiles_bury_object(volume->cache, object, fan,
428 old_file->f_path.dentry,
429 FSCACHE_OBJECT_INVALIDATED);
430 }
431 fput(old_file);
432 }
433
434 _leave(" = t");
435 return true;
436
437failed:
438 _leave(" = f");
439 return false;
440}
441
442const struct fscache_cache_ops cachefiles_cache_ops = {
443 .name = "cachefiles",
444 .acquire_volume = cachefiles_acquire_volume,
445 .free_volume = cachefiles_free_volume,
446 .lookup_cookie = cachefiles_lookup_cookie,
447 .withdraw_cookie = cachefiles_withdraw_cookie,
448 .invalidate_cookie = cachefiles_invalidate_cookie,
449 .begin_operation = cachefiles_begin_operation,
450 .resize_cookie = cachefiles_resize_cookie,
451 .prepare_to_write = cachefiles_prepare_to_write,
452};
1/* FS-Cache interface to CacheFiles
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/slab.h>
13#include <linux/mount.h>
14#include <linux/buffer_head.h>
15#include "internal.h"
16
17#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
18
19struct cachefiles_lookup_data {
20 struct cachefiles_xattr *auxdata; /* auxiliary data */
21 char *key; /* key path */
22};
23
24static int cachefiles_attr_changed(struct fscache_object *_object);
25
26/*
27 * allocate an object record for a cookie lookup and prepare the lookup data
28 */
29static struct fscache_object *cachefiles_alloc_object(
30 struct fscache_cache *_cache,
31 struct fscache_cookie *cookie)
32{
33 struct cachefiles_lookup_data *lookup_data;
34 struct cachefiles_object *object;
35 struct cachefiles_cache *cache;
36 struct cachefiles_xattr *auxdata;
37 unsigned keylen, auxlen;
38 void *buffer;
39 char *key;
40
41 cache = container_of(_cache, struct cachefiles_cache, cache);
42
43 _enter("{%s},%p,", cache->cache.identifier, cookie);
44
45 lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
46 if (!lookup_data)
47 goto nomem_lookup_data;
48
49 /* create a new object record and a temporary leaf image */
50 object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
51 if (!object)
52 goto nomem_object;
53
54 ASSERTCMP(object->backer, ==, NULL);
55
56 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
57 atomic_set(&object->usage, 1);
58
59 fscache_object_init(&object->fscache, cookie, &cache->cache);
60
61 object->type = cookie->def->type;
62
63 /* get hold of the raw key
64 * - stick the length on the front and leave space on the back for the
65 * encoder
66 */
67 buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
68 if (!buffer)
69 goto nomem_buffer;
70
71 keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
72 ASSERTCMP(keylen, <, 512);
73
74 *(uint16_t *)buffer = keylen;
75 ((char *)buffer)[keylen + 2] = 0;
76 ((char *)buffer)[keylen + 3] = 0;
77 ((char *)buffer)[keylen + 4] = 0;
78
79 /* turn the raw key into something that can work with as a filename */
80 key = cachefiles_cook_key(buffer, keylen + 2, object->type);
81 if (!key)
82 goto nomem_key;
83
84 /* get hold of the auxiliary data and prepend the object type */
85 auxdata = buffer;
86 auxlen = 0;
87 if (cookie->def->get_aux) {
88 auxlen = cookie->def->get_aux(cookie->netfs_data,
89 auxdata->data, 511);
90 ASSERTCMP(auxlen, <, 511);
91 }
92
93 auxdata->len = auxlen + 1;
94 auxdata->type = cookie->def->type;
95
96 lookup_data->auxdata = auxdata;
97 lookup_data->key = key;
98 object->lookup_data = lookup_data;
99
100 _leave(" = %p [%p]", &object->fscache, lookup_data);
101 return &object->fscache;
102
103nomem_key:
104 kfree(buffer);
105nomem_buffer:
106 BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
107 kmem_cache_free(cachefiles_object_jar, object);
108 fscache_object_destroyed(&cache->cache);
109nomem_object:
110 kfree(lookup_data);
111nomem_lookup_data:
112 _leave(" = -ENOMEM");
113 return ERR_PTR(-ENOMEM);
114}
115
116/*
117 * attempt to look up the nominated node in this cache
118 * - return -ETIMEDOUT to be scheduled again
119 */
120static int cachefiles_lookup_object(struct fscache_object *_object)
121{
122 struct cachefiles_lookup_data *lookup_data;
123 struct cachefiles_object *parent, *object;
124 struct cachefiles_cache *cache;
125 const struct cred *saved_cred;
126 int ret;
127
128 _enter("{OBJ%x}", _object->debug_id);
129
130 cache = container_of(_object->cache, struct cachefiles_cache, cache);
131 parent = container_of(_object->parent,
132 struct cachefiles_object, fscache);
133 object = container_of(_object, struct cachefiles_object, fscache);
134 lookup_data = object->lookup_data;
135
136 ASSERTCMP(lookup_data, !=, NULL);
137
138 /* look up the key, creating any missing bits */
139 cachefiles_begin_secure(cache, &saved_cred);
140 ret = cachefiles_walk_to_object(parent, object,
141 lookup_data->key,
142 lookup_data->auxdata);
143 cachefiles_end_secure(cache, saved_cred);
144
145 /* polish off by setting the attributes of non-index files */
146 if (ret == 0 &&
147 object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
148 cachefiles_attr_changed(&object->fscache);
149
150 if (ret < 0 && ret != -ETIMEDOUT) {
151 if (ret != -ENOBUFS)
152 printk(KERN_WARNING
153 "CacheFiles: Lookup failed error %d\n", ret);
154 fscache_object_lookup_error(&object->fscache);
155 }
156
157 _leave(" [%d]", ret);
158 return ret;
159}
160
161/*
162 * indication of lookup completion
163 */
164static void cachefiles_lookup_complete(struct fscache_object *_object)
165{
166 struct cachefiles_object *object;
167
168 object = container_of(_object, struct cachefiles_object, fscache);
169
170 _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
171
172 if (object->lookup_data) {
173 kfree(object->lookup_data->key);
174 kfree(object->lookup_data->auxdata);
175 kfree(object->lookup_data);
176 object->lookup_data = NULL;
177 }
178}
179
180/*
181 * increment the usage count on an inode object (may fail if unmounting)
182 */
183static
184struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
185{
186 struct cachefiles_object *object =
187 container_of(_object, struct cachefiles_object, fscache);
188
189 _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
190
191#ifdef CACHEFILES_DEBUG_SLAB
192 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
193#endif
194
195 atomic_inc(&object->usage);
196 return &object->fscache;
197}
198
199/*
200 * update the auxiliary data for an object object on disk
201 */
202static void cachefiles_update_object(struct fscache_object *_object)
203{
204 struct cachefiles_object *object;
205 struct cachefiles_xattr *auxdata;
206 struct cachefiles_cache *cache;
207 struct fscache_cookie *cookie;
208 const struct cred *saved_cred;
209 unsigned auxlen;
210
211 _enter("{OBJ%x}", _object->debug_id);
212
213 object = container_of(_object, struct cachefiles_object, fscache);
214 cache = container_of(object->fscache.cache, struct cachefiles_cache,
215 cache);
216 cookie = object->fscache.cookie;
217
218 if (!cookie->def->get_aux) {
219 _leave(" [no aux]");
220 return;
221 }
222
223 auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
224 if (!auxdata) {
225 _leave(" [nomem]");
226 return;
227 }
228
229 auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
230 ASSERTCMP(auxlen, <, 511);
231
232 auxdata->len = auxlen + 1;
233 auxdata->type = cookie->def->type;
234
235 cachefiles_begin_secure(cache, &saved_cred);
236 cachefiles_update_object_xattr(object, auxdata);
237 cachefiles_end_secure(cache, saved_cred);
238 kfree(auxdata);
239 _leave("");
240}
241
242/*
243 * discard the resources pinned by an object and effect retirement if
244 * requested
245 */
246static void cachefiles_drop_object(struct fscache_object *_object)
247{
248 struct cachefiles_object *object;
249 struct cachefiles_cache *cache;
250 const struct cred *saved_cred;
251
252 ASSERT(_object);
253
254 object = container_of(_object, struct cachefiles_object, fscache);
255
256 _enter("{OBJ%x,%d}",
257 object->fscache.debug_id, atomic_read(&object->usage));
258
259 cache = container_of(object->fscache.cache,
260 struct cachefiles_cache, cache);
261
262#ifdef CACHEFILES_DEBUG_SLAB
263 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
264#endif
265
266 /* delete retired objects */
267 if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
268 _object != cache->cache.fsdef
269 ) {
270 _debug("- retire object OBJ%x", object->fscache.debug_id);
271 cachefiles_begin_secure(cache, &saved_cred);
272 cachefiles_delete_object(cache, object);
273 cachefiles_end_secure(cache, saved_cred);
274 }
275
276 /* close the filesystem stuff attached to the object */
277 if (object->backer != object->dentry)
278 dput(object->backer);
279 object->backer = NULL;
280
281 /* note that the object is now inactive */
282 if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
283 write_lock(&cache->active_lock);
284 if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE,
285 &object->flags))
286 BUG();
287 rb_erase(&object->active_node, &cache->active_nodes);
288 wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
289 write_unlock(&cache->active_lock);
290 }
291
292 dput(object->dentry);
293 object->dentry = NULL;
294
295 _leave("");
296}
297
298/*
299 * dispose of a reference to an object
300 */
301static void cachefiles_put_object(struct fscache_object *_object)
302{
303 struct cachefiles_object *object;
304 struct fscache_cache *cache;
305
306 ASSERT(_object);
307
308 object = container_of(_object, struct cachefiles_object, fscache);
309
310 _enter("{OBJ%x,%d}",
311 object->fscache.debug_id, atomic_read(&object->usage));
312
313#ifdef CACHEFILES_DEBUG_SLAB
314 ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
315#endif
316
317 ASSERTIFCMP(object->fscache.parent,
318 object->fscache.parent->n_children, >, 0);
319
320 if (atomic_dec_and_test(&object->usage)) {
321 _debug("- kill object OBJ%x", object->fscache.debug_id);
322
323 ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
324 ASSERTCMP(object->fscache.parent, ==, NULL);
325 ASSERTCMP(object->backer, ==, NULL);
326 ASSERTCMP(object->dentry, ==, NULL);
327 ASSERTCMP(object->fscache.n_ops, ==, 0);
328 ASSERTCMP(object->fscache.n_children, ==, 0);
329
330 if (object->lookup_data) {
331 kfree(object->lookup_data->key);
332 kfree(object->lookup_data->auxdata);
333 kfree(object->lookup_data);
334 object->lookup_data = NULL;
335 }
336
337 cache = object->fscache.cache;
338 fscache_object_destroy(&object->fscache);
339 kmem_cache_free(cachefiles_object_jar, object);
340 fscache_object_destroyed(cache);
341 }
342
343 _leave("");
344}
345
346/*
347 * sync a cache
348 */
349static void cachefiles_sync_cache(struct fscache_cache *_cache)
350{
351 struct cachefiles_cache *cache;
352 const struct cred *saved_cred;
353 int ret;
354
355 _enter("%p", _cache);
356
357 cache = container_of(_cache, struct cachefiles_cache, cache);
358
359 /* make sure all pages pinned by operations on behalf of the netfs are
360 * written to disc */
361 cachefiles_begin_secure(cache, &saved_cred);
362 down_read(&cache->mnt->mnt_sb->s_umount);
363 ret = sync_filesystem(cache->mnt->mnt_sb);
364 up_read(&cache->mnt->mnt_sb->s_umount);
365 cachefiles_end_secure(cache, saved_cred);
366
367 if (ret == -EIO)
368 cachefiles_io_error(cache,
369 "Attempt to sync backing fs superblock"
370 " returned error %d",
371 ret);
372}
373
374/*
375 * notification the attributes on an object have changed
376 * - called with reads/writes excluded by FS-Cache
377 */
378static int cachefiles_attr_changed(struct fscache_object *_object)
379{
380 struct cachefiles_object *object;
381 struct cachefiles_cache *cache;
382 const struct cred *saved_cred;
383 struct iattr newattrs;
384 uint64_t ni_size;
385 loff_t oi_size;
386 int ret;
387
388 _object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
389
390 _enter("{OBJ%x},[%llu]",
391 _object->debug_id, (unsigned long long) ni_size);
392
393 object = container_of(_object, struct cachefiles_object, fscache);
394 cache = container_of(object->fscache.cache,
395 struct cachefiles_cache, cache);
396
397 if (ni_size == object->i_size)
398 return 0;
399
400 if (!object->backer)
401 return -ENOBUFS;
402
403 ASSERT(S_ISREG(object->backer->d_inode->i_mode));
404
405 fscache_set_store_limit(&object->fscache, ni_size);
406
407 oi_size = i_size_read(object->backer->d_inode);
408 if (oi_size == ni_size)
409 return 0;
410
411 cachefiles_begin_secure(cache, &saved_cred);
412 mutex_lock(&object->backer->d_inode->i_mutex);
413
414 /* if there's an extension to a partial page at the end of the backing
415 * file, we need to discard the partial page so that we pick up new
416 * data after it */
417 if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
418 _debug("discard tail %llx", oi_size);
419 newattrs.ia_valid = ATTR_SIZE;
420 newattrs.ia_size = oi_size & PAGE_MASK;
421 ret = notify_change(object->backer, &newattrs);
422 if (ret < 0)
423 goto truncate_failed;
424 }
425
426 newattrs.ia_valid = ATTR_SIZE;
427 newattrs.ia_size = ni_size;
428 ret = notify_change(object->backer, &newattrs);
429
430truncate_failed:
431 mutex_unlock(&object->backer->d_inode->i_mutex);
432 cachefiles_end_secure(cache, saved_cred);
433
434 if (ret == -EIO) {
435 fscache_set_store_limit(&object->fscache, 0);
436 cachefiles_io_error_obj(object, "Size set failed");
437 ret = -ENOBUFS;
438 }
439
440 _leave(" = %d", ret);
441 return ret;
442}
443
444/*
445 * dissociate a cache from all the pages it was backing
446 */
447static void cachefiles_dissociate_pages(struct fscache_cache *cache)
448{
449 _enter("");
450}
451
452const struct fscache_cache_ops cachefiles_cache_ops = {
453 .name = "cachefiles",
454 .alloc_object = cachefiles_alloc_object,
455 .lookup_object = cachefiles_lookup_object,
456 .lookup_complete = cachefiles_lookup_complete,
457 .grab_object = cachefiles_grab_object,
458 .update_object = cachefiles_update_object,
459 .drop_object = cachefiles_drop_object,
460 .put_object = cachefiles_put_object,
461 .sync_cache = cachefiles_sync_cache,
462 .attr_changed = cachefiles_attr_changed,
463 .read_or_alloc_page = cachefiles_read_or_alloc_page,
464 .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
465 .allocate_page = cachefiles_allocate_page,
466 .allocate_pages = cachefiles_allocate_pages,
467 .write_page = cachefiles_write_page,
468 .uncache_page = cachefiles_uncache_page,
469 .dissociate_pages = cachefiles_dissociate_pages,
470};