xref: /linux/fs/cachefiles/internal.h (revision 83ab4b461eb7bdf90984eb56d4954dbe11e926d4)
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 
cachefiles_in_ondemand_mode(struct cachefiles_cache * cache)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
cachefiles_cres_file(struct netfs_cache_resources * cres)154 struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
155 {
156 	return cres->cache_priv2;
157 }
158 
159 static inline
cachefiles_cres_object(struct netfs_cache_resources * cres)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  */
cachefiles_state_changed(struct cachefiles_cache * cache)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 
cachefiles_register_error_injection(void)208 static inline int cachefiles_register_error_injection(void)
209 {
210 	return 0;
211 }
212 
cachefiles_unregister_error_injection(void)213 static inline void cachefiles_unregister_error_injection(void)
214 {
215 }
216 #endif
217 
218 
cachefiles_inject_read_error(void)219 static inline int cachefiles_inject_read_error(void)
220 {
221 	return cachefiles_error_injection_state & 2 ? -EIO : 0;
222 }
223 
cachefiles_inject_write_error(void)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 
cachefiles_inject_remove_error(void)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 
cachefiles_ondemand_is_reopening_read(struct cachefiles_req * req)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
cachefiles_ondemand_daemon_read(struct cachefiles_cache * cache,char __user * _buffer,size_t buflen)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 
cachefiles_ondemand_init_object(struct cachefiles_object * object)355 static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
356 {
357 	return 0;
358 }
359 
cachefiles_ondemand_clean_object(struct cachefiles_object * object)360 static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
361 {
362 }
363 
cachefiles_ondemand_read(struct cachefiles_object * object,loff_t pos,size_t len)364 static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
365 					   loff_t pos, size_t len)
366 {
367 	return -EOPNOTSUPP;
368 }
369 
cachefiles_ondemand_init_obj_info(struct cachefiles_object * obj,struct cachefiles_volume * volume)370 static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
371 						struct cachefiles_volume *volume)
372 {
373 	return 0;
374 }
cachefiles_ondemand_deinit_obj_info(struct cachefiles_object * obj)375 static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
376 {
377 }
378 
cachefiles_ondemand_is_reopening_read(struct cachefiles_req * req)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 
cachefiles_begin_secure(struct cachefiles_cache * cache,const struct cred ** _saved_cred)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 
cachefiles_end_secure(struct cachefiles_cache * cache,const struct cred * saved_cred)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