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1/*
2 * Cleancache frontend
3 *
4 * This code provides the generic "frontend" layer to call a matching
5 * "backend" driver implementation of cleancache. See
6 * Documentation/vm/cleancache.txt for more information.
7 *
8 * Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
9 * Author: Dan Magenheimer
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2.
12 */
13
14#include <linux/module.h>
15#include <linux/fs.h>
16#include <linux/exportfs.h>
17#include <linux/mm.h>
18#include <linux/debugfs.h>
19#include <linux/cleancache.h>
20
21/*
22 * cleancache_ops is set by cleancache_ops_register to contain the pointers
23 * to the cleancache "backend" implementation functions.
24 */
25static struct cleancache_ops *cleancache_ops __read_mostly;
26
27/*
28 * Counters available via /sys/kernel/debug/frontswap (if debugfs is
29 * properly configured. These are for information only so are not protected
30 * against increment races.
31 */
32static u64 cleancache_succ_gets;
33static u64 cleancache_failed_gets;
34static u64 cleancache_puts;
35static u64 cleancache_invalidates;
36
37/*
38 * When no backend is registered all calls to init_fs and init_shared_fs
39 * are registered and fake poolids (FAKE_FS_POOLID_OFFSET or
40 * FAKE_SHARED_FS_POOLID_OFFSET, plus offset in the respective array
41 * [shared_|]fs_poolid_map) are given to the respective super block
42 * (sb->cleancache_poolid) and no tmem_pools are created. When a backend
43 * registers with cleancache the previous calls to init_fs and init_shared_fs
44 * are executed to create tmem_pools and set the respective poolids. While no
45 * backend is registered all "puts", "gets" and "flushes" are ignored or failed.
46 */
47#define MAX_INITIALIZABLE_FS 32
48#define FAKE_FS_POOLID_OFFSET 1000
49#define FAKE_SHARED_FS_POOLID_OFFSET 2000
50
51#define FS_NO_BACKEND (-1)
52#define FS_UNKNOWN (-2)
53static int fs_poolid_map[MAX_INITIALIZABLE_FS];
54static int shared_fs_poolid_map[MAX_INITIALIZABLE_FS];
55static char *uuids[MAX_INITIALIZABLE_FS];
56/*
57 * Mutex for the [shared_|]fs_poolid_map to guard against multiple threads
58 * invoking umount (and ending in __cleancache_invalidate_fs) and also multiple
59 * threads calling mount (and ending up in __cleancache_init_[shared|]fs).
60 */
61static DEFINE_MUTEX(poolid_mutex);
62/*
63 * When set to false (default) all calls to the cleancache functions, except
64 * the __cleancache_invalidate_fs and __cleancache_init_[shared|]fs are guarded
65 * by the if (!cleancache_ops) return. This means multiple threads (from
66 * different filesystems) will be checking cleancache_ops. The usage of a
67 * bool instead of a atomic_t or a bool guarded by a spinlock is OK - we are
68 * OK if the time between the backend's have been initialized (and
69 * cleancache_ops has been set to not NULL) and when the filesystems start
70 * actually calling the backends. The inverse (when unloading) is obviously
71 * not good - but this shim does not do that (yet).
72 */
73
74/*
75 * The backends and filesystems work all asynchronously. This is b/c the
76 * backends can be built as modules.
77 * The usual sequence of events is:
78 * a) mount / -> __cleancache_init_fs is called. We set the
79 * [shared_|]fs_poolid_map and uuids for.
80 *
81 * b). user does I/Os -> we call the rest of __cleancache_* functions
82 * which return immediately as cleancache_ops is false.
83 *
84 * c). modprobe zcache -> cleancache_register_ops. We init the backend
85 * and set cleancache_ops to true, and for any fs_poolid_map
86 * (which is set by __cleancache_init_fs) we initialize the poolid.
87 *
88 * d). user does I/Os -> now that cleancache_ops is true all the
89 * __cleancache_* functions can call the backend. They all check
90 * that fs_poolid_map is valid and if so invoke the backend.
91 *
92 * e). umount / -> __cleancache_invalidate_fs, the fs_poolid_map is
93 * reset (which is the second check in the __cleancache_* ops
94 * to call the backend).
95 *
96 * The sequence of event could also be c), followed by a), and d). and e). The
97 * c) would not happen anymore. There is also the chance of c), and one thread
98 * doing a) + d), and another doing e). For that case we depend on the
99 * filesystem calling __cleancache_invalidate_fs in the proper sequence (so
100 * that it handles all I/Os before it invalidates the fs (which is last part
101 * of unmounting process).
102 *
103 * Note: The acute reader will notice that there is no "rmmod zcache" case.
104 * This is b/c the functionality for that is not yet implemented and when
105 * done, will require some extra locking not yet devised.
106 */
107
108/*
109 * Register operations for cleancache, returning previous thus allowing
110 * detection of multiple backends and possible nesting.
111 */
112struct cleancache_ops *cleancache_register_ops(struct cleancache_ops *ops)
113{
114 struct cleancache_ops *old = cleancache_ops;
115 int i;
116
117 mutex_lock(&poolid_mutex);
118 for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
119 if (fs_poolid_map[i] == FS_NO_BACKEND)
120 fs_poolid_map[i] = ops->init_fs(PAGE_SIZE);
121 if (shared_fs_poolid_map[i] == FS_NO_BACKEND)
122 shared_fs_poolid_map[i] = ops->init_shared_fs
123 (uuids[i], PAGE_SIZE);
124 }
125 /*
126 * We MUST set cleancache_ops _after_ we have called the backends
127 * init_fs or init_shared_fs functions. Otherwise the compiler might
128 * re-order where cleancache_ops is set in this function.
129 */
130 barrier();
131 cleancache_ops = ops;
132 mutex_unlock(&poolid_mutex);
133 return old;
134}
135EXPORT_SYMBOL(cleancache_register_ops);
136
137/* Called by a cleancache-enabled filesystem at time of mount */
138void __cleancache_init_fs(struct super_block *sb)
139{
140 int i;
141
142 mutex_lock(&poolid_mutex);
143 for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
144 if (fs_poolid_map[i] == FS_UNKNOWN) {
145 sb->cleancache_poolid = i + FAKE_FS_POOLID_OFFSET;
146 if (cleancache_ops)
147 fs_poolid_map[i] = cleancache_ops->init_fs(PAGE_SIZE);
148 else
149 fs_poolid_map[i] = FS_NO_BACKEND;
150 break;
151 }
152 }
153 mutex_unlock(&poolid_mutex);
154}
155EXPORT_SYMBOL(__cleancache_init_fs);
156
157/* Called by a cleancache-enabled clustered filesystem at time of mount */
158void __cleancache_init_shared_fs(char *uuid, struct super_block *sb)
159{
160 int i;
161
162 mutex_lock(&poolid_mutex);
163 for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
164 if (shared_fs_poolid_map[i] == FS_UNKNOWN) {
165 sb->cleancache_poolid = i + FAKE_SHARED_FS_POOLID_OFFSET;
166 uuids[i] = uuid;
167 if (cleancache_ops)
168 shared_fs_poolid_map[i] = cleancache_ops->init_shared_fs
169 (uuid, PAGE_SIZE);
170 else
171 shared_fs_poolid_map[i] = FS_NO_BACKEND;
172 break;
173 }
174 }
175 mutex_unlock(&poolid_mutex);
176}
177EXPORT_SYMBOL(__cleancache_init_shared_fs);
178
179/*
180 * If the filesystem uses exportable filehandles, use the filehandle as
181 * the key, else use the inode number.
182 */
183static int cleancache_get_key(struct inode *inode,
184 struct cleancache_filekey *key)
185{
186 int (*fhfn)(struct inode *, __u32 *fh, int *, struct inode *);
187 int len = 0, maxlen = CLEANCACHE_KEY_MAX;
188 struct super_block *sb = inode->i_sb;
189
190 key->u.ino = inode->i_ino;
191 if (sb->s_export_op != NULL) {
192 fhfn = sb->s_export_op->encode_fh;
193 if (fhfn) {
194 len = (*fhfn)(inode, &key->u.fh[0], &maxlen, NULL);
195 if (len <= FILEID_ROOT || len == FILEID_INVALID)
196 return -1;
197 if (maxlen > CLEANCACHE_KEY_MAX)
198 return -1;
199 }
200 }
201 return 0;
202}
203
204/*
205 * Returns a pool_id that is associated with a given fake poolid.
206 */
207static int get_poolid_from_fake(int fake_pool_id)
208{
209 if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET)
210 return shared_fs_poolid_map[fake_pool_id -
211 FAKE_SHARED_FS_POOLID_OFFSET];
212 else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET)
213 return fs_poolid_map[fake_pool_id - FAKE_FS_POOLID_OFFSET];
214 return FS_NO_BACKEND;
215}
216
217/*
218 * "Get" data from cleancache associated with the poolid/inode/index
219 * that were specified when the data was put to cleanache and, if
220 * successful, use it to fill the specified page with data and return 0.
221 * The pageframe is unchanged and returns -1 if the get fails.
222 * Page must be locked by caller.
223 *
224 * The function has two checks before any action is taken - whether
225 * a backend is registered and whether the sb->cleancache_poolid
226 * is correct.
227 */
228int __cleancache_get_page(struct page *page)
229{
230 int ret = -1;
231 int pool_id;
232 int fake_pool_id;
233 struct cleancache_filekey key = { .u.key = { 0 } };
234
235 if (!cleancache_ops) {
236 cleancache_failed_gets++;
237 goto out;
238 }
239
240 VM_BUG_ON_PAGE(!PageLocked(page), page);
241 fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
242 if (fake_pool_id < 0)
243 goto out;
244 pool_id = get_poolid_from_fake(fake_pool_id);
245
246 if (cleancache_get_key(page->mapping->host, &key) < 0)
247 goto out;
248
249 if (pool_id >= 0)
250 ret = cleancache_ops->get_page(pool_id,
251 key, page->index, page);
252 if (ret == 0)
253 cleancache_succ_gets++;
254 else
255 cleancache_failed_gets++;
256out:
257 return ret;
258}
259EXPORT_SYMBOL(__cleancache_get_page);
260
261/*
262 * "Put" data from a page to cleancache and associate it with the
263 * (previously-obtained per-filesystem) poolid and the page's,
264 * inode and page index. Page must be locked. Note that a put_page
265 * always "succeeds", though a subsequent get_page may succeed or fail.
266 *
267 * The function has two checks before any action is taken - whether
268 * a backend is registered and whether the sb->cleancache_poolid
269 * is correct.
270 */
271void __cleancache_put_page(struct page *page)
272{
273 int pool_id;
274 int fake_pool_id;
275 struct cleancache_filekey key = { .u.key = { 0 } };
276
277 if (!cleancache_ops) {
278 cleancache_puts++;
279 return;
280 }
281
282 VM_BUG_ON_PAGE(!PageLocked(page), page);
283 fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
284 if (fake_pool_id < 0)
285 return;
286
287 pool_id = get_poolid_from_fake(fake_pool_id);
288
289 if (pool_id >= 0 &&
290 cleancache_get_key(page->mapping->host, &key) >= 0) {
291 cleancache_ops->put_page(pool_id, key, page->index, page);
292 cleancache_puts++;
293 }
294}
295EXPORT_SYMBOL(__cleancache_put_page);
296
297/*
298 * Invalidate any data from cleancache associated with the poolid and the
299 * page's inode and page index so that a subsequent "get" will fail.
300 *
301 * The function has two checks before any action is taken - whether
302 * a backend is registered and whether the sb->cleancache_poolid
303 * is correct.
304 */
305void __cleancache_invalidate_page(struct address_space *mapping,
306 struct page *page)
307{
308 /* careful... page->mapping is NULL sometimes when this is called */
309 int pool_id;
310 int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
311 struct cleancache_filekey key = { .u.key = { 0 } };
312
313 if (!cleancache_ops)
314 return;
315
316 if (fake_pool_id >= 0) {
317 pool_id = get_poolid_from_fake(fake_pool_id);
318 if (pool_id < 0)
319 return;
320
321 VM_BUG_ON_PAGE(!PageLocked(page), page);
322 if (cleancache_get_key(mapping->host, &key) >= 0) {
323 cleancache_ops->invalidate_page(pool_id,
324 key, page->index);
325 cleancache_invalidates++;
326 }
327 }
328}
329EXPORT_SYMBOL(__cleancache_invalidate_page);
330
331/*
332 * Invalidate all data from cleancache associated with the poolid and the
333 * mappings's inode so that all subsequent gets to this poolid/inode
334 * will fail.
335 *
336 * The function has two checks before any action is taken - whether
337 * a backend is registered and whether the sb->cleancache_poolid
338 * is correct.
339 */
340void __cleancache_invalidate_inode(struct address_space *mapping)
341{
342 int pool_id;
343 int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
344 struct cleancache_filekey key = { .u.key = { 0 } };
345
346 if (!cleancache_ops)
347 return;
348
349 if (fake_pool_id < 0)
350 return;
351
352 pool_id = get_poolid_from_fake(fake_pool_id);
353
354 if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
355 cleancache_ops->invalidate_inode(pool_id, key);
356}
357EXPORT_SYMBOL(__cleancache_invalidate_inode);
358
359/*
360 * Called by any cleancache-enabled filesystem at time of unmount;
361 * note that pool_id is surrendered and may be returned by a subsequent
362 * cleancache_init_fs or cleancache_init_shared_fs.
363 */
364void __cleancache_invalidate_fs(struct super_block *sb)
365{
366 int index;
367 int fake_pool_id = sb->cleancache_poolid;
368 int old_poolid = fake_pool_id;
369
370 mutex_lock(&poolid_mutex);
371 if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET) {
372 index = fake_pool_id - FAKE_SHARED_FS_POOLID_OFFSET;
373 old_poolid = shared_fs_poolid_map[index];
374 shared_fs_poolid_map[index] = FS_UNKNOWN;
375 uuids[index] = NULL;
376 } else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET) {
377 index = fake_pool_id - FAKE_FS_POOLID_OFFSET;
378 old_poolid = fs_poolid_map[index];
379 fs_poolid_map[index] = FS_UNKNOWN;
380 }
381 sb->cleancache_poolid = -1;
382 if (cleancache_ops)
383 cleancache_ops->invalidate_fs(old_poolid);
384 mutex_unlock(&poolid_mutex);
385}
386EXPORT_SYMBOL(__cleancache_invalidate_fs);
387
388static int __init init_cleancache(void)
389{
390 int i;
391
392#ifdef CONFIG_DEBUG_FS
393 struct dentry *root = debugfs_create_dir("cleancache", NULL);
394 if (root == NULL)
395 return -ENXIO;
396 debugfs_create_u64("succ_gets", S_IRUGO, root, &cleancache_succ_gets);
397 debugfs_create_u64("failed_gets", S_IRUGO,
398 root, &cleancache_failed_gets);
399 debugfs_create_u64("puts", S_IRUGO, root, &cleancache_puts);
400 debugfs_create_u64("invalidates", S_IRUGO,
401 root, &cleancache_invalidates);
402#endif
403 for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
404 fs_poolid_map[i] = FS_UNKNOWN;
405 shared_fs_poolid_map[i] = FS_UNKNOWN;
406 }
407 return 0;
408}
409module_init(init_cleancache)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Cleancache frontend
4 *
5 * This code provides the generic "frontend" layer to call a matching
6 * "backend" driver implementation of cleancache. See
7 * Documentation/vm/cleancache.rst for more information.
8 *
9 * Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
10 * Author: Dan Magenheimer
11 */
12
13#include <linux/module.h>
14#include <linux/fs.h>
15#include <linux/exportfs.h>
16#include <linux/mm.h>
17#include <linux/debugfs.h>
18#include <linux/cleancache.h>
19
20/*
21 * cleancache_ops is set by cleancache_register_ops to contain the pointers
22 * to the cleancache "backend" implementation functions.
23 */
24static const struct cleancache_ops *cleancache_ops __read_mostly;
25
26/*
27 * Counters available via /sys/kernel/debug/cleancache (if debugfs is
28 * properly configured. These are for information only so are not protected
29 * against increment races.
30 */
31static u64 cleancache_succ_gets;
32static u64 cleancache_failed_gets;
33static u64 cleancache_puts;
34static u64 cleancache_invalidates;
35
36static void cleancache_register_ops_sb(struct super_block *sb, void *unused)
37{
38 switch (sb->cleancache_poolid) {
39 case CLEANCACHE_NO_BACKEND:
40 __cleancache_init_fs(sb);
41 break;
42 case CLEANCACHE_NO_BACKEND_SHARED:
43 __cleancache_init_shared_fs(sb);
44 break;
45 }
46}
47
48/*
49 * Register operations for cleancache. Returns 0 on success.
50 */
51int cleancache_register_ops(const struct cleancache_ops *ops)
52{
53 if (cmpxchg(&cleancache_ops, NULL, ops))
54 return -EBUSY;
55
56 /*
57 * A cleancache backend can be built as a module and hence loaded after
58 * a cleancache enabled filesystem has called cleancache_init_fs. To
59 * handle such a scenario, here we call ->init_fs or ->init_shared_fs
60 * for each active super block. To differentiate between local and
61 * shared filesystems, we temporarily initialize sb->cleancache_poolid
62 * to CLEANCACHE_NO_BACKEND or CLEANCACHE_NO_BACKEND_SHARED
63 * respectively in case there is no backend registered at the time
64 * cleancache_init_fs or cleancache_init_shared_fs is called.
65 *
66 * Since filesystems can be mounted concurrently with cleancache
67 * backend registration, we have to be careful to guarantee that all
68 * cleancache enabled filesystems that has been mounted by the time
69 * cleancache_register_ops is called has got and all mounted later will
70 * get cleancache_poolid. This is assured by the following statements
71 * tied together:
72 *
73 * a) iterate_supers skips only those super blocks that has started
74 * ->kill_sb
75 *
76 * b) if iterate_supers encounters a super block that has not finished
77 * ->mount yet, it waits until it is finished
78 *
79 * c) cleancache_init_fs is called from ->mount and
80 * cleancache_invalidate_fs is called from ->kill_sb
81 *
82 * d) we call iterate_supers after cleancache_ops has been set
83 *
84 * From a) it follows that if iterate_supers skips a super block, then
85 * either the super block is already dead, in which case we do not need
86 * to bother initializing cleancache for it, or it was mounted after we
87 * initiated iterate_supers. In the latter case, it must have seen
88 * cleancache_ops set according to d) and initialized cleancache from
89 * ->mount by itself according to c). This proves that we call
90 * ->init_fs at least once for each active super block.
91 *
92 * From b) and c) it follows that if iterate_supers encounters a super
93 * block that has already started ->init_fs, it will wait until ->mount
94 * and hence ->init_fs has finished, then check cleancache_poolid, see
95 * that it has already been set and therefore do nothing. This proves
96 * that we call ->init_fs no more than once for each super block.
97 *
98 * Combined together, the last two paragraphs prove the function
99 * correctness.
100 *
101 * Note that various cleancache callbacks may proceed before this
102 * function is called or even concurrently with it, but since
103 * CLEANCACHE_NO_BACKEND is negative, they will all result in a noop
104 * until the corresponding ->init_fs has been actually called and
105 * cleancache_ops has been set.
106 */
107 iterate_supers(cleancache_register_ops_sb, NULL);
108 return 0;
109}
110EXPORT_SYMBOL(cleancache_register_ops);
111
112/* Called by a cleancache-enabled filesystem at time of mount */
113void __cleancache_init_fs(struct super_block *sb)
114{
115 int pool_id = CLEANCACHE_NO_BACKEND;
116
117 if (cleancache_ops) {
118 pool_id = cleancache_ops->init_fs(PAGE_SIZE);
119 if (pool_id < 0)
120 pool_id = CLEANCACHE_NO_POOL;
121 }
122 sb->cleancache_poolid = pool_id;
123}
124EXPORT_SYMBOL(__cleancache_init_fs);
125
126/* Called by a cleancache-enabled clustered filesystem at time of mount */
127void __cleancache_init_shared_fs(struct super_block *sb)
128{
129 int pool_id = CLEANCACHE_NO_BACKEND_SHARED;
130
131 if (cleancache_ops) {
132 pool_id = cleancache_ops->init_shared_fs(&sb->s_uuid, PAGE_SIZE);
133 if (pool_id < 0)
134 pool_id = CLEANCACHE_NO_POOL;
135 }
136 sb->cleancache_poolid = pool_id;
137}
138EXPORT_SYMBOL(__cleancache_init_shared_fs);
139
140/*
141 * If the filesystem uses exportable filehandles, use the filehandle as
142 * the key, else use the inode number.
143 */
144static int cleancache_get_key(struct inode *inode,
145 struct cleancache_filekey *key)
146{
147 int (*fhfn)(struct inode *, __u32 *fh, int *, struct inode *);
148 int len = 0, maxlen = CLEANCACHE_KEY_MAX;
149 struct super_block *sb = inode->i_sb;
150
151 key->u.ino = inode->i_ino;
152 if (sb->s_export_op != NULL) {
153 fhfn = sb->s_export_op->encode_fh;
154 if (fhfn) {
155 len = (*fhfn)(inode, &key->u.fh[0], &maxlen, NULL);
156 if (len <= FILEID_ROOT || len == FILEID_INVALID)
157 return -1;
158 if (maxlen > CLEANCACHE_KEY_MAX)
159 return -1;
160 }
161 }
162 return 0;
163}
164
165/*
166 * "Get" data from cleancache associated with the poolid/inode/index
167 * that were specified when the data was put to cleanache and, if
168 * successful, use it to fill the specified page with data and return 0.
169 * The pageframe is unchanged and returns -1 if the get fails.
170 * Page must be locked by caller.
171 *
172 * The function has two checks before any action is taken - whether
173 * a backend is registered and whether the sb->cleancache_poolid
174 * is correct.
175 */
176int __cleancache_get_page(struct page *page)
177{
178 int ret = -1;
179 int pool_id;
180 struct cleancache_filekey key = { .u.key = { 0 } };
181
182 if (!cleancache_ops) {
183 cleancache_failed_gets++;
184 goto out;
185 }
186
187 VM_BUG_ON_PAGE(!PageLocked(page), page);
188 pool_id = page->mapping->host->i_sb->cleancache_poolid;
189 if (pool_id < 0)
190 goto out;
191
192 if (cleancache_get_key(page->mapping->host, &key) < 0)
193 goto out;
194
195 ret = cleancache_ops->get_page(pool_id, key, page->index, page);
196 if (ret == 0)
197 cleancache_succ_gets++;
198 else
199 cleancache_failed_gets++;
200out:
201 return ret;
202}
203EXPORT_SYMBOL(__cleancache_get_page);
204
205/*
206 * "Put" data from a page to cleancache and associate it with the
207 * (previously-obtained per-filesystem) poolid and the page's,
208 * inode and page index. Page must be locked. Note that a put_page
209 * always "succeeds", though a subsequent get_page may succeed or fail.
210 *
211 * The function has two checks before any action is taken - whether
212 * a backend is registered and whether the sb->cleancache_poolid
213 * is correct.
214 */
215void __cleancache_put_page(struct page *page)
216{
217 int pool_id;
218 struct cleancache_filekey key = { .u.key = { 0 } };
219
220 if (!cleancache_ops) {
221 cleancache_puts++;
222 return;
223 }
224
225 VM_BUG_ON_PAGE(!PageLocked(page), page);
226 pool_id = page->mapping->host->i_sb->cleancache_poolid;
227 if (pool_id >= 0 &&
228 cleancache_get_key(page->mapping->host, &key) >= 0) {
229 cleancache_ops->put_page(pool_id, key, page->index, page);
230 cleancache_puts++;
231 }
232}
233EXPORT_SYMBOL(__cleancache_put_page);
234
235/*
236 * Invalidate any data from cleancache associated with the poolid and the
237 * page's inode and page index so that a subsequent "get" will fail.
238 *
239 * The function has two checks before any action is taken - whether
240 * a backend is registered and whether the sb->cleancache_poolid
241 * is correct.
242 */
243void __cleancache_invalidate_page(struct address_space *mapping,
244 struct page *page)
245{
246 /* careful... page->mapping is NULL sometimes when this is called */
247 int pool_id = mapping->host->i_sb->cleancache_poolid;
248 struct cleancache_filekey key = { .u.key = { 0 } };
249
250 if (!cleancache_ops)
251 return;
252
253 if (pool_id >= 0) {
254 VM_BUG_ON_PAGE(!PageLocked(page), page);
255 if (cleancache_get_key(mapping->host, &key) >= 0) {
256 cleancache_ops->invalidate_page(pool_id,
257 key, page->index);
258 cleancache_invalidates++;
259 }
260 }
261}
262EXPORT_SYMBOL(__cleancache_invalidate_page);
263
264/*
265 * Invalidate all data from cleancache associated with the poolid and the
266 * mappings's inode so that all subsequent gets to this poolid/inode
267 * will fail.
268 *
269 * The function has two checks before any action is taken - whether
270 * a backend is registered and whether the sb->cleancache_poolid
271 * is correct.
272 */
273void __cleancache_invalidate_inode(struct address_space *mapping)
274{
275 int pool_id = mapping->host->i_sb->cleancache_poolid;
276 struct cleancache_filekey key = { .u.key = { 0 } };
277
278 if (!cleancache_ops)
279 return;
280
281 if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
282 cleancache_ops->invalidate_inode(pool_id, key);
283}
284EXPORT_SYMBOL(__cleancache_invalidate_inode);
285
286/*
287 * Called by any cleancache-enabled filesystem at time of unmount;
288 * note that pool_id is surrendered and may be returned by a subsequent
289 * cleancache_init_fs or cleancache_init_shared_fs.
290 */
291void __cleancache_invalidate_fs(struct super_block *sb)
292{
293 int pool_id;
294
295 pool_id = sb->cleancache_poolid;
296 sb->cleancache_poolid = CLEANCACHE_NO_POOL;
297
298 if (cleancache_ops && pool_id >= 0)
299 cleancache_ops->invalidate_fs(pool_id);
300}
301EXPORT_SYMBOL(__cleancache_invalidate_fs);
302
303static int __init init_cleancache(void)
304{
305#ifdef CONFIG_DEBUG_FS
306 struct dentry *root = debugfs_create_dir("cleancache", NULL);
307
308 debugfs_create_u64("succ_gets", 0444, root, &cleancache_succ_gets);
309 debugfs_create_u64("failed_gets", 0444, root, &cleancache_failed_gets);
310 debugfs_create_u64("puts", 0444, root, &cleancache_puts);
311 debugfs_create_u64("invalidates", 0444, root, &cleancache_invalidates);
312#endif
313 return 0;
314}
315module_init(init_cleancache)