1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* General netfs cache on cache files internal defs
3 *
4 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #ifdef pr_fmt
9 #undef pr_fmt
10 #endif
11
12 #define pr_fmt(fmt) "CacheFiles: " fmt
13
14
15 #include <linux/fscache-cache.h>
16 #include <linux/cred.h>
17 #include <linux/security.h>
18 #include <linux/xarray.h>
19 #include <linux/cachefiles.h>
20
21 #define CACHEFILES_DIO_BLOCK_SIZE 4096
22
23 struct cachefiles_cache;
24 struct cachefiles_object;
25
26 enum cachefiles_content {
27 /* These values are saved on disk */
28 CACHEFILES_CONTENT_NO_DATA = 0, /* No content stored */
29 CACHEFILES_CONTENT_SINGLE = 1, /* Content is monolithic, all is present */
30 CACHEFILES_CONTENT_ALL = 2, /* Content is all present, no map */
31 CACHEFILES_CONTENT_BACKFS_MAP = 3, /* Content is piecemeal, mapped through backing fs */
32 CACHEFILES_CONTENT_DIRTY = 4, /* Content is dirty (only seen on disk) */
33 nr__cachefiles_content
34 };
35
36 /*
37 * Cached volume representation.
38 */
39 struct cachefiles_volume {
40 struct cachefiles_cache *cache;
41 struct list_head cache_link; /* Link in cache->volumes */
42 struct fscache_volume *vcookie; /* The netfs's representation */
43 struct dentry *dentry; /* The volume dentry */
44 struct dentry *fanout[256]; /* Fanout subdirs */
45 };
46
47 enum cachefiles_object_state {
48 CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */
49 CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */
50 CACHEFILES_ONDEMAND_OBJSTATE_REOPENING, /* Object that was closed and is being reopened. */
51 CACHEFILES_ONDEMAND_OBJSTATE_DROPPING, /* Object is being dropped. */
52 };
53
54 struct cachefiles_ondemand_info {
55 struct work_struct ondemand_work;
56 int ondemand_id;
57 enum cachefiles_object_state state;
58 struct cachefiles_object *object;
59 spinlock_t lock;
60 };
61
62 /*
63 * Backing file state.
64 */
65 struct cachefiles_object {
66 struct fscache_cookie *cookie; /* Netfs data storage object cookie */
67 struct cachefiles_volume *volume; /* Cache volume that holds this object */
68 struct list_head cache_link; /* Link in cache->*_list */
69 struct file *file; /* The file representing this object */
70 char *d_name; /* Backing file name */
71 int debug_id;
72 spinlock_t lock;
73 refcount_t ref;
74 u8 d_name_len; /* Length of filename */
75 enum cachefiles_content content_info:8; /* Info about content presence */
76 unsigned long flags;
77 #define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
78 #ifdef CONFIG_CACHEFILES_ONDEMAND
79 struct cachefiles_ondemand_info *ondemand;
80 #endif
81 };
82
83 #define CACHEFILES_ONDEMAND_ID_CLOSED -1
84
85 /*
86 * Cache files cache definition
87 */
88 struct cachefiles_cache {
89 struct fscache_cache *cache; /* Cache cookie */
90 struct vfsmount *mnt; /* mountpoint holding the cache */
91 struct dentry *store; /* Directory into which live objects go */
92 struct dentry *graveyard; /* directory into which dead objects go */
93 struct file *cachefilesd; /* manager daemon handle */
94 struct list_head volumes; /* List of volume objects */
95 struct list_head object_list; /* List of active objects */
96 spinlock_t object_list_lock; /* Lock for volumes and object_list */
97 const struct cred *cache_cred; /* security override for accessing cache */
98 struct mutex daemon_mutex; /* command serialisation mutex */
99 wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
100 atomic_t gravecounter; /* graveyard uniquifier */
101 atomic_t f_released; /* number of objects released lately */
102 atomic_long_t b_released; /* number of blocks released lately */
103 atomic_long_t b_writing; /* Number of blocks being written */
104 unsigned frun_percent; /* when to stop culling (% files) */
105 unsigned fcull_percent; /* when to start culling (% files) */
106 unsigned fstop_percent; /* when to stop allocating (% files) */
107 unsigned brun_percent; /* when to stop culling (% blocks) */
108 unsigned bcull_percent; /* when to start culling (% blocks) */
109 unsigned bstop_percent; /* when to stop allocating (% blocks) */
110 unsigned bsize; /* cache's block size */
111 unsigned bshift; /* ilog2(bsize) */
112 uint64_t frun; /* when to stop culling */
113 uint64_t fcull; /* when to start culling */
114 uint64_t fstop; /* when to stop allocating */
115 sector_t brun; /* when to stop culling */
116 sector_t bcull; /* when to start culling */
117 sector_t bstop; /* when to stop allocating */
118 unsigned long flags;
119 #define CACHEFILES_READY 0 /* T if cache prepared */
120 #define CACHEFILES_DEAD 1 /* T if cache dead */
121 #define CACHEFILES_CULLING 2 /* T if cull engaged */
122 #define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
123 #define CACHEFILES_ONDEMAND_MODE 4 /* T if in on-demand read mode */
124 char *rootdirname; /* name of cache root directory */
125 char *secctx; /* LSM security context */
126 char *tag; /* cache binding tag */
127 refcount_t unbind_pincount;/* refcount to do daemon unbind */
128 struct xarray reqs; /* xarray of pending on-demand requests */
129 unsigned long req_id_next;
130 struct xarray ondemand_ids; /* xarray for ondemand_id allocation */
131 u32 ondemand_id_next;
132 u32 msg_id_next;
133 };
134
135 static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache)
136 {
137 return IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND) &&
138 test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
139 }
140
141 struct cachefiles_req {
142 struct cachefiles_object *object;
143 struct completion done;
144 refcount_t ref;
145 int error;
146 struct cachefiles_msg msg;
147 };
148
149 #define CACHEFILES_REQ_NEW XA_MARK_1
150
151 #include <trace/events/cachefiles.h>
152
153 static inline
154 struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
155 {
156 return cres->cache_priv2;
157 }
158
159 static inline
160 struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
161 {
162 return fscache_cres_cookie(cres)->cache_priv;
163 }
164
165 /*
166 * note change of state for daemon
167 */
168 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
169 {
170 set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
171 wake_up_all(&cache->daemon_pollwq);
172 }
173
174 /*
175 * cache.c
176 */
177 extern int cachefiles_add_cache(struct cachefiles_cache *cache);
178 extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
179
180 enum cachefiles_has_space_for {
181 cachefiles_has_space_check,
182 cachefiles_has_space_for_write,
183 cachefiles_has_space_for_create,
184 };
185 extern int cachefiles_has_space(struct cachefiles_cache *cache,
186 unsigned fnr, unsigned bnr,
187 enum cachefiles_has_space_for reason);
188
189 /*
190 * daemon.c
191 */
192 extern const struct file_operations cachefiles_daemon_fops;
193 extern void cachefiles_flush_reqs(struct cachefiles_cache *cache);
194 extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
195 extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
196
197 /*
198 * error_inject.c
199 */
200 #ifdef CONFIG_CACHEFILES_ERROR_INJECTION
201 extern unsigned int cachefiles_error_injection_state;
202 extern int cachefiles_register_error_injection(void);
203 extern void cachefiles_unregister_error_injection(void);
204
205 #else
206 #define cachefiles_error_injection_state 0
207
208 static inline int cachefiles_register_error_injection(void)
209 {
210 return 0;
211 }
212
213 static inline void cachefiles_unregister_error_injection(void)
214 {
215 }
216 #endif
217
218
219 static inline int cachefiles_inject_read_error(void)
220 {
221 return cachefiles_error_injection_state & 2 ? -EIO : 0;
222 }
223
224 static inline int cachefiles_inject_write_error(void)
225 {
226 return cachefiles_error_injection_state & 2 ? -EIO :
227 cachefiles_error_injection_state & 1 ? -ENOSPC :
228 0;
229 }
230
231 static inline int cachefiles_inject_remove_error(void)
232 {
233 return cachefiles_error_injection_state & 2 ? -EIO : 0;
234 }
235
236 /*
237 * interface.c
238 */
239 extern const struct fscache_cache_ops cachefiles_cache_ops;
240 extern void cachefiles_see_object(struct cachefiles_object *object,
241 enum cachefiles_obj_ref_trace why);
242 extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
243 enum cachefiles_obj_ref_trace why);
244 extern void cachefiles_put_object(struct cachefiles_object *object,
245 enum cachefiles_obj_ref_trace why);
246
247 /*
248 * io.c
249 */
250 extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
251 enum fscache_want_state want_state);
252 extern int __cachefiles_prepare_write(struct cachefiles_object *object,
253 struct file *file,
254 loff_t *_start, size_t *_len, size_t upper_len,
255 bool no_space_allocated_yet);
256 extern int __cachefiles_write(struct cachefiles_object *object,
257 struct file *file,
258 loff_t start_pos,
259 struct iov_iter *iter,
260 netfs_io_terminated_t term_func,
261 void *term_func_priv);
262
263 /*
264 * key.c
265 */
266 extern bool cachefiles_cook_key(struct cachefiles_object *object);
267
268 /*
269 * main.c
270 */
271 extern struct kmem_cache *cachefiles_object_jar;
272
273 /*
274 * namei.c
275 */
276 extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
277 struct file *file);
278 extern int cachefiles_bury_object(struct cachefiles_cache *cache,
279 struct cachefiles_object *object,
280 struct dentry *dir,
281 struct dentry *rep,
282 enum fscache_why_object_killed why);
283 extern int cachefiles_delete_object(struct cachefiles_object *object,
284 enum fscache_why_object_killed why);
285 extern bool cachefiles_look_up_object(struct cachefiles_object *object);
286 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
287 struct dentry *dir,
288 const char *name,
289 bool *_is_new);
290 extern void cachefiles_put_directory(struct dentry *dir);
291
292 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
293 char *filename);
294
295 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
296 struct dentry *dir, char *filename);
297 extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
298 extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
299 struct cachefiles_object *object);
300
301 /*
302 * ondemand.c
303 */
304 #ifdef CONFIG_CACHEFILES_ONDEMAND
305 extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
306 char __user *_buffer, size_t buflen);
307
308 extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
309 char *args);
310
311 extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache,
312 char *args);
313
314 extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
315 extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
316
317 extern int cachefiles_ondemand_read(struct cachefiles_object *object,
318 loff_t pos, size_t len);
319
320 extern int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
321 struct cachefiles_volume *volume);
322 extern void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj);
323
324 #define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \
325 static inline bool \
326 cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
327 { \
328 return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
329 } \
330 \
331 static inline void \
332 cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
333 { \
334 object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
335 }
336
337 CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
338 CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
339 CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
340 CACHEFILES_OBJECT_STATE_FUNCS(dropping, DROPPING);
341
342 static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
343 {
344 return cachefiles_ondemand_object_is_reopening(req->object) &&
345 req->msg.opcode == CACHEFILES_OP_READ;
346 }
347
348 #else
349 static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
350 char __user *_buffer, size_t buflen)
351 {
352 return -EOPNOTSUPP;
353 }
354
355 static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
356 {
357 return 0;
358 }
359
360 static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
361 {
362 }
363
364 static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
365 loff_t pos, size_t len)
366 {
367 return -EOPNOTSUPP;
368 }
369
370 static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
371 struct cachefiles_volume *volume)
372 {
373 return 0;
374 }
375 static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
376 {
377 }
378
379 static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
380 {
381 return false;
382 }
383 #endif
384
385 /*
386 * security.c
387 */
388 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
389 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
390 struct dentry *root,
391 const struct cred **_saved_cred);
392
393 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
394 const struct cred **_saved_cred)
395 {
396 *_saved_cred = override_creds(cache->cache_cred);
397 }
398
399 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
400 const struct cred *saved_cred)
401 {
402 revert_creds(saved_cred);
403 }
404
405 /*
406 * volume.c
407 */
408 void cachefiles_acquire_volume(struct fscache_volume *volume);
409 void cachefiles_free_volume(struct fscache_volume *volume);
410 void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
411
412 /*
413 * xattr.c
414 */
415 extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
416 extern int cachefiles_check_auxdata(struct cachefiles_object *object,
417 struct file *file);
418 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
419 struct cachefiles_object *object,
420 struct dentry *dentry);
421 extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
422 extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
423 extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
424
425 /*
426 * Error handling
427 */
428 #define cachefiles_io_error(___cache, FMT, ...) \
429 do { \
430 pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
431 fscache_io_error((___cache)->cache); \
432 set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
433 if (cachefiles_in_ondemand_mode(___cache)) \
434 cachefiles_flush_reqs(___cache); \
435 } while (0)
436
437 #define cachefiles_io_error_obj(object, FMT, ...) \
438 do { \
439 struct cachefiles_cache *___cache; \
440 \
441 ___cache = (object)->volume->cache; \
442 cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
443 (object)->debug_id); \
444 } while (0)
445
446
447 /*
448 * Debug tracing
449 */
450 extern unsigned cachefiles_debug;
451 #define CACHEFILES_DEBUG_KENTER 1
452 #define CACHEFILES_DEBUG_KLEAVE 2
453 #define CACHEFILES_DEBUG_KDEBUG 4
454
455 #define dbgprintk(FMT, ...) \
456 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
457
458 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
459 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
460 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
461
462
463 #if defined(__KDEBUG)
464 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
465 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
466 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
467
468 #elif defined(CONFIG_CACHEFILES_DEBUG)
469 #define _enter(FMT, ...) \
470 do { \
471 if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
472 kenter(FMT, ##__VA_ARGS__); \
473 } while (0)
474
475 #define _leave(FMT, ...) \
476 do { \
477 if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
478 kleave(FMT, ##__VA_ARGS__); \
479 } while (0)
480
481 #define _debug(FMT, ...) \
482 do { \
483 if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
484 kdebug(FMT, ##__VA_ARGS__); \
485 } while (0)
486
487 #else
488 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
489 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
490 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
491 #endif
492
493 #if 1 /* defined(__KDEBUGALL) */
494
495 #define ASSERT(X) \
496 do { \
497 if (unlikely(!(X))) { \
498 pr_err("\n"); \
499 pr_err("Assertion failed\n"); \
500 BUG(); \
501 } \
502 } while (0)
503
504 #define ASSERTCMP(X, OP, Y) \
505 do { \
506 if (unlikely(!((X) OP (Y)))) { \
507 pr_err("\n"); \
508 pr_err("Assertion failed\n"); \
509 pr_err("%lx " #OP " %lx is false\n", \
510 (unsigned long)(X), (unsigned long)(Y)); \
511 BUG(); \
512 } \
513 } while (0)
514
515 #define ASSERTIF(C, X) \
516 do { \
517 if (unlikely((C) && !(X))) { \
518 pr_err("\n"); \
519 pr_err("Assertion failed\n"); \
520 BUG(); \
521 } \
522 } while (0)
523
524 #define ASSERTIFCMP(C, X, OP, Y) \
525 do { \
526 if (unlikely((C) && !((X) OP (Y)))) { \
527 pr_err("\n"); \
528 pr_err("Assertion failed\n"); \
529 pr_err("%lx " #OP " %lx is false\n", \
530 (unsigned long)(X), (unsigned long)(Y)); \
531 BUG(); \
532 } \
533 } while (0)
534
535 #else
536
537 #define ASSERT(X) do {} while (0)
538 #define ASSERTCMP(X, OP, Y) do {} while (0)
539 #define ASSERTIF(C, X) do {} while (0)
540 #define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
541
542 #endif
543
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