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 /*
48 * Backing file state.
49 */
50 struct cachefiles_object {
51 struct fscache_cookie *cookie; /* Netfs data storage object cookie */
52 struct cachefiles_volume *volume; /* Cache volume that holds this object */
53 struct list_head cache_link; /* Link in cache->*_list */
54 struct file *file; /* The file representing this object */
55 char *d_name; /* Backing file name */
56 int debug_id;
57 spinlock_t lock;
58 refcount_t ref;
59 u8 d_name_len; /* Length of filename */
60 enum cachefiles_content content_info:8; /* Info about content presence */
61 unsigned long flags;
62 #define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
63 #ifdef CONFIG_CACHEFILES_ONDEMAND
64 int ondemand_id;
65 #endif
66 };
67
68 #define CACHEFILES_ONDEMAND_ID_CLOSED -1
69
70 /*
71 * Cache files cache definition
72 */
73 struct cachefiles_cache {
74 struct fscache_cache *cache; /* Cache cookie */
75 struct vfsmount *mnt; /* mountpoint holding the cache */
76 struct dentry *store; /* Directory into which live objects go */
77 struct dentry *graveyard; /* directory into which dead objects go */
78 struct file *cachefilesd; /* manager daemon handle */
79 struct list_head volumes; /* List of volume objects */
80 struct list_head object_list; /* List of active objects */
81 spinlock_t object_list_lock; /* Lock for volumes and object_list */
82 const struct cred *cache_cred; /* security override for accessing cache */
83 struct mutex daemon_mutex; /* command serialisation mutex */
84 wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
85 atomic_t gravecounter; /* graveyard uniquifier */
86 atomic_t f_released; /* number of objects released lately */
87 atomic_long_t b_released; /* number of blocks released lately */
88 atomic_long_t b_writing; /* Number of blocks being written */
89 unsigned frun_percent; /* when to stop culling (% files) */
90 unsigned fcull_percent; /* when to start culling (% files) */
91 unsigned fstop_percent; /* when to stop allocating (% files) */
92 unsigned brun_percent; /* when to stop culling (% blocks) */
93 unsigned bcull_percent; /* when to start culling (% blocks) */
94 unsigned bstop_percent; /* when to stop allocating (% blocks) */
95 unsigned bsize; /* cache's block size */
96 unsigned bshift; /* ilog2(bsize) */
97 uint64_t frun; /* when to stop culling */
98 uint64_t fcull; /* when to start culling */
99 uint64_t fstop; /* when to stop allocating */
100 sector_t brun; /* when to stop culling */
101 sector_t bcull; /* when to start culling */
102 sector_t bstop; /* when to stop allocating */
103 unsigned long flags;
104 #define CACHEFILES_READY 0 /* T if cache prepared */
105 #define CACHEFILES_DEAD 1 /* T if cache dead */
106 #define CACHEFILES_CULLING 2 /* T if cull engaged */
107 #define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
108 #define CACHEFILES_ONDEMAND_MODE 4 /* T if in on-demand read mode */
109 char *rootdirname; /* name of cache root directory */
110 char *secctx; /* LSM security context */
111 char *tag; /* cache binding tag */
112 refcount_t unbind_pincount;/* refcount to do daemon unbind */
113 struct xarray reqs; /* xarray of pending on-demand requests */
114 unsigned long req_id_next;
115 struct xarray ondemand_ids; /* xarray for ondemand_id allocation */
116 u32 ondemand_id_next;
117 };
118
cachefiles_in_ondemand_mode(struct cachefiles_cache * cache)119 static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache)
120 {
121 return IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND) &&
122 test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
123 }
124
125 struct cachefiles_req {
126 struct cachefiles_object *object;
127 struct completion done;
128 int error;
129 struct cachefiles_msg msg;
130 };
131
132 #define CACHEFILES_REQ_NEW XA_MARK_1
133
134 #include <trace/events/cachefiles.h>
135
136 static inline
cachefiles_cres_file(struct netfs_cache_resources * cres)137 struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
138 {
139 return cres->cache_priv2;
140 }
141
142 static inline
cachefiles_cres_object(struct netfs_cache_resources * cres)143 struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
144 {
145 return fscache_cres_cookie(cres)->cache_priv;
146 }
147
148 /*
149 * note change of state for daemon
150 */
cachefiles_state_changed(struct cachefiles_cache * cache)151 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
152 {
153 set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
154 wake_up_all(&cache->daemon_pollwq);
155 }
156
157 /*
158 * cache.c
159 */
160 extern int cachefiles_add_cache(struct cachefiles_cache *cache);
161 extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
162
163 enum cachefiles_has_space_for {
164 cachefiles_has_space_check,
165 cachefiles_has_space_for_write,
166 cachefiles_has_space_for_create,
167 };
168 extern int cachefiles_has_space(struct cachefiles_cache *cache,
169 unsigned fnr, unsigned bnr,
170 enum cachefiles_has_space_for reason);
171
172 /*
173 * daemon.c
174 */
175 extern const struct file_operations cachefiles_daemon_fops;
176 extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
177 extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
178
179 /*
180 * error_inject.c
181 */
182 #ifdef CONFIG_CACHEFILES_ERROR_INJECTION
183 extern unsigned int cachefiles_error_injection_state;
184 extern int cachefiles_register_error_injection(void);
185 extern void cachefiles_unregister_error_injection(void);
186
187 #else
188 #define cachefiles_error_injection_state 0
189
cachefiles_register_error_injection(void)190 static inline int cachefiles_register_error_injection(void)
191 {
192 return 0;
193 }
194
cachefiles_unregister_error_injection(void)195 static inline void cachefiles_unregister_error_injection(void)
196 {
197 }
198 #endif
199
200
cachefiles_inject_read_error(void)201 static inline int cachefiles_inject_read_error(void)
202 {
203 return cachefiles_error_injection_state & 2 ? -EIO : 0;
204 }
205
cachefiles_inject_write_error(void)206 static inline int cachefiles_inject_write_error(void)
207 {
208 return cachefiles_error_injection_state & 2 ? -EIO :
209 cachefiles_error_injection_state & 1 ? -ENOSPC :
210 0;
211 }
212
cachefiles_inject_remove_error(void)213 static inline int cachefiles_inject_remove_error(void)
214 {
215 return cachefiles_error_injection_state & 2 ? -EIO : 0;
216 }
217
218 /*
219 * interface.c
220 */
221 extern const struct fscache_cache_ops cachefiles_cache_ops;
222 extern void cachefiles_see_object(struct cachefiles_object *object,
223 enum cachefiles_obj_ref_trace why);
224 extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
225 enum cachefiles_obj_ref_trace why);
226 extern void cachefiles_put_object(struct cachefiles_object *object,
227 enum cachefiles_obj_ref_trace why);
228
229 /*
230 * io.c
231 */
232 extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
233 enum fscache_want_state want_state);
234 extern int __cachefiles_prepare_write(struct cachefiles_object *object,
235 struct file *file,
236 loff_t *_start, size_t *_len,
237 bool no_space_allocated_yet);
238 extern int __cachefiles_write(struct cachefiles_object *object,
239 struct file *file,
240 loff_t start_pos,
241 struct iov_iter *iter,
242 netfs_io_terminated_t term_func,
243 void *term_func_priv);
244
245 /*
246 * key.c
247 */
248 extern bool cachefiles_cook_key(struct cachefiles_object *object);
249
250 /*
251 * main.c
252 */
253 extern struct kmem_cache *cachefiles_object_jar;
254
255 /*
256 * namei.c
257 */
258 extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
259 struct file *file);
260 extern int cachefiles_bury_object(struct cachefiles_cache *cache,
261 struct cachefiles_object *object,
262 struct dentry *dir,
263 struct dentry *rep,
264 enum fscache_why_object_killed why);
265 extern int cachefiles_delete_object(struct cachefiles_object *object,
266 enum fscache_why_object_killed why);
267 extern bool cachefiles_look_up_object(struct cachefiles_object *object);
268 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
269 struct dentry *dir,
270 const char *name,
271 bool *_is_new);
272 extern void cachefiles_put_directory(struct dentry *dir);
273
274 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
275 char *filename);
276
277 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
278 struct dentry *dir, char *filename);
279 extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
280 extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
281 struct cachefiles_object *object);
282
283 /*
284 * ondemand.c
285 */
286 #ifdef CONFIG_CACHEFILES_ONDEMAND
287 extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
288 char __user *_buffer, size_t buflen);
289
290 extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
291 char *args);
292
293 extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
294 extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
295
296 extern int cachefiles_ondemand_read(struct cachefiles_object *object,
297 loff_t pos, size_t len);
298
299 #else
cachefiles_ondemand_daemon_read(struct cachefiles_cache * cache,char __user * _buffer,size_t buflen)300 static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
301 char __user *_buffer, size_t buflen)
302 {
303 return -EOPNOTSUPP;
304 }
305
cachefiles_ondemand_init_object(struct cachefiles_object * object)306 static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
307 {
308 return 0;
309 }
310
cachefiles_ondemand_clean_object(struct cachefiles_object * object)311 static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
312 {
313 }
314
cachefiles_ondemand_read(struct cachefiles_object * object,loff_t pos,size_t len)315 static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
316 loff_t pos, size_t len)
317 {
318 return -EOPNOTSUPP;
319 }
320 #endif
321
322 /*
323 * security.c
324 */
325 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
326 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
327 struct dentry *root,
328 const struct cred **_saved_cred);
329
cachefiles_begin_secure(struct cachefiles_cache * cache,const struct cred ** _saved_cred)330 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
331 const struct cred **_saved_cred)
332 {
333 *_saved_cred = override_creds(cache->cache_cred);
334 }
335
cachefiles_end_secure(struct cachefiles_cache * cache,const struct cred * saved_cred)336 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
337 const struct cred *saved_cred)
338 {
339 revert_creds(saved_cred);
340 }
341
342 /*
343 * volume.c
344 */
345 void cachefiles_acquire_volume(struct fscache_volume *volume);
346 void cachefiles_free_volume(struct fscache_volume *volume);
347 void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
348
349 /*
350 * xattr.c
351 */
352 extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
353 extern int cachefiles_check_auxdata(struct cachefiles_object *object,
354 struct file *file);
355 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
356 struct cachefiles_object *object,
357 struct dentry *dentry);
358 extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
359 extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
360 extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
361
362 /*
363 * Error handling
364 */
365 #define cachefiles_io_error(___cache, FMT, ...) \
366 do { \
367 pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
368 fscache_io_error((___cache)->cache); \
369 set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
370 } while (0)
371
372 #define cachefiles_io_error_obj(object, FMT, ...) \
373 do { \
374 struct cachefiles_cache *___cache; \
375 \
376 ___cache = (object)->volume->cache; \
377 cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
378 (object)->debug_id); \
379 } while (0)
380
381
382 /*
383 * Debug tracing
384 */
385 extern unsigned cachefiles_debug;
386 #define CACHEFILES_DEBUG_KENTER 1
387 #define CACHEFILES_DEBUG_KLEAVE 2
388 #define CACHEFILES_DEBUG_KDEBUG 4
389
390 #define dbgprintk(FMT, ...) \
391 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
392
393 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
394 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
395 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
396
397
398 #if defined(__KDEBUG)
399 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
400 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
401 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
402
403 #elif defined(CONFIG_CACHEFILES_DEBUG)
404 #define _enter(FMT, ...) \
405 do { \
406 if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
407 kenter(FMT, ##__VA_ARGS__); \
408 } while (0)
409
410 #define _leave(FMT, ...) \
411 do { \
412 if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
413 kleave(FMT, ##__VA_ARGS__); \
414 } while (0)
415
416 #define _debug(FMT, ...) \
417 do { \
418 if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
419 kdebug(FMT, ##__VA_ARGS__); \
420 } while (0)
421
422 #else
423 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
424 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
425 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
426 #endif
427
428 #if 1 /* defined(__KDEBUGALL) */
429
430 #define ASSERT(X) \
431 do { \
432 if (unlikely(!(X))) { \
433 pr_err("\n"); \
434 pr_err("Assertion failed\n"); \
435 BUG(); \
436 } \
437 } while (0)
438
439 #define ASSERTCMP(X, OP, Y) \
440 do { \
441 if (unlikely(!((X) OP (Y)))) { \
442 pr_err("\n"); \
443 pr_err("Assertion failed\n"); \
444 pr_err("%lx " #OP " %lx is false\n", \
445 (unsigned long)(X), (unsigned long)(Y)); \
446 BUG(); \
447 } \
448 } while (0)
449
450 #define ASSERTIF(C, X) \
451 do { \
452 if (unlikely((C) && !(X))) { \
453 pr_err("\n"); \
454 pr_err("Assertion failed\n"); \
455 BUG(); \
456 } \
457 } while (0)
458
459 #define ASSERTIFCMP(C, X, OP, Y) \
460 do { \
461 if (unlikely((C) && !((X) OP (Y)))) { \
462 pr_err("\n"); \
463 pr_err("Assertion failed\n"); \
464 pr_err("%lx " #OP " %lx is false\n", \
465 (unsigned long)(X), (unsigned long)(Y)); \
466 BUG(); \
467 } \
468 } while (0)
469
470 #else
471
472 #define ASSERT(X) do {} while (0)
473 #define ASSERTCMP(X, OP, Y) do {} while (0)
474 #define ASSERTIF(C, X) do {} while (0)
475 #define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
476
477 #endif
478