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