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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
23struct cachefiles_cache;
24struct cachefiles_object;
25
26enum 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 */
39struct 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
47enum 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
54struct 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 */
65struct 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 */
88struct 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 *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 u32 msg_id_next;
132 u32 secid; /* LSM security id */
133 bool have_secid; /* whether "secid" was set */
134};
135
136static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache)
137{
138 return IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND) &&
139 test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
140}
141
142struct cachefiles_req {
143 struct cachefiles_object *object;
144 struct completion done;
145 refcount_t ref;
146 int error;
147 struct cachefiles_msg msg;
148};
149
150#define CACHEFILES_REQ_NEW XA_MARK_1
151
152#include <trace/events/cachefiles.h>
153
154static inline
155struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
156{
157 return cres->cache_priv2;
158}
159
160static inline
161struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
162{
163 return fscache_cres_cookie(cres)->cache_priv;
164}
165
166/*
167 * note change of state for daemon
168 */
169static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
170{
171 set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
172 wake_up_all(&cache->daemon_pollwq);
173}
174
175/*
176 * cache.c
177 */
178extern int cachefiles_add_cache(struct cachefiles_cache *cache);
179extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
180
181enum cachefiles_has_space_for {
182 cachefiles_has_space_check,
183 cachefiles_has_space_for_write,
184 cachefiles_has_space_for_create,
185};
186extern int cachefiles_has_space(struct cachefiles_cache *cache,
187 unsigned fnr, unsigned bnr,
188 enum cachefiles_has_space_for reason);
189
190/*
191 * daemon.c
192 */
193extern const struct file_operations cachefiles_daemon_fops;
194extern void cachefiles_flush_reqs(struct cachefiles_cache *cache);
195extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
196extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
197
198/*
199 * error_inject.c
200 */
201#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
202extern unsigned int cachefiles_error_injection_state;
203extern int cachefiles_register_error_injection(void);
204extern void cachefiles_unregister_error_injection(void);
205
206#else
207#define cachefiles_error_injection_state 0
208
209static inline int cachefiles_register_error_injection(void)
210{
211 return 0;
212}
213
214static inline void cachefiles_unregister_error_injection(void)
215{
216}
217#endif
218
219
220static inline int cachefiles_inject_read_error(void)
221{
222 return cachefiles_error_injection_state & 2 ? -EIO : 0;
223}
224
225static inline int cachefiles_inject_write_error(void)
226{
227 return cachefiles_error_injection_state & 2 ? -EIO :
228 cachefiles_error_injection_state & 1 ? -ENOSPC :
229 0;
230}
231
232static inline int cachefiles_inject_remove_error(void)
233{
234 return cachefiles_error_injection_state & 2 ? -EIO : 0;
235}
236
237/*
238 * interface.c
239 */
240extern const struct fscache_cache_ops cachefiles_cache_ops;
241extern void cachefiles_see_object(struct cachefiles_object *object,
242 enum cachefiles_obj_ref_trace why);
243extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
244 enum cachefiles_obj_ref_trace why);
245extern void cachefiles_put_object(struct cachefiles_object *object,
246 enum cachefiles_obj_ref_trace why);
247
248/*
249 * io.c
250 */
251extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
252 enum fscache_want_state want_state);
253extern int __cachefiles_prepare_write(struct cachefiles_object *object,
254 struct file *file,
255 loff_t *_start, size_t *_len, size_t upper_len,
256 bool no_space_allocated_yet);
257extern int __cachefiles_write(struct cachefiles_object *object,
258 struct file *file,
259 loff_t start_pos,
260 struct iov_iter *iter,
261 netfs_io_terminated_t term_func,
262 void *term_func_priv);
263
264/*
265 * key.c
266 */
267extern bool cachefiles_cook_key(struct cachefiles_object *object);
268
269/*
270 * main.c
271 */
272extern struct kmem_cache *cachefiles_object_jar;
273
274/*
275 * namei.c
276 */
277extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
278 struct file *file);
279extern int cachefiles_bury_object(struct cachefiles_cache *cache,
280 struct cachefiles_object *object,
281 struct dentry *dir,
282 struct dentry *rep,
283 enum fscache_why_object_killed why);
284extern int cachefiles_delete_object(struct cachefiles_object *object,
285 enum fscache_why_object_killed why);
286extern bool cachefiles_look_up_object(struct cachefiles_object *object);
287extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
288 struct dentry *dir,
289 const char *name,
290 bool *_is_new);
291extern void cachefiles_put_directory(struct dentry *dir);
292
293extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
294 char *filename);
295
296extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
297 struct dentry *dir, char *filename);
298extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
299extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
300 struct cachefiles_object *object);
301
302/*
303 * ondemand.c
304 */
305#ifdef CONFIG_CACHEFILES_ONDEMAND
306extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
307 char __user *_buffer, size_t buflen);
308
309extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
310 char *args);
311
312extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache,
313 char *args);
314
315extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
316extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
317
318extern int cachefiles_ondemand_read(struct cachefiles_object *object,
319 loff_t pos, size_t len);
320
321extern int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
322 struct cachefiles_volume *volume);
323extern void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj);
324
325#define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE) \
326static inline bool \
327cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
328{ \
329 return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
330} \
331 \
332static inline void \
333cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
334{ \
335 object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
336}
337
338CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
339CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
340CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
341CACHEFILES_OBJECT_STATE_FUNCS(dropping, DROPPING);
342
343static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
344{
345 return cachefiles_ondemand_object_is_reopening(req->object) &&
346 req->msg.opcode == CACHEFILES_OP_READ;
347}
348
349#else
350static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
351 char __user *_buffer, size_t buflen)
352{
353 return -EOPNOTSUPP;
354}
355
356static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
357{
358 return 0;
359}
360
361static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
362{
363}
364
365static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
366 loff_t pos, size_t len)
367{
368 return -EOPNOTSUPP;
369}
370
371static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
372 struct cachefiles_volume *volume)
373{
374 return 0;
375}
376static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
377{
378}
379
380static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
381{
382 return false;
383}
384#endif
385
386/*
387 * security.c
388 */
389extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
390extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
391 struct dentry *root,
392 const struct cred **_saved_cred);
393
394static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
395 const struct cred **_saved_cred)
396{
397 *_saved_cred = override_creds(cache->cache_cred);
398}
399
400static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
401 const struct cred *saved_cred)
402{
403 revert_creds(saved_cred);
404}
405
406/*
407 * volume.c
408 */
409void cachefiles_acquire_volume(struct fscache_volume *volume);
410void cachefiles_free_volume(struct fscache_volume *volume);
411void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
412
413/*
414 * xattr.c
415 */
416extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
417extern int cachefiles_check_auxdata(struct cachefiles_object *object,
418 struct file *file);
419extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
420 struct cachefiles_object *object,
421 struct dentry *dentry);
422extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
423extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
424extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
425
426/*
427 * Error handling
428 */
429#define cachefiles_io_error(___cache, FMT, ...) \
430do { \
431 pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
432 fscache_io_error((___cache)->cache); \
433 set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
434 if (cachefiles_in_ondemand_mode(___cache)) \
435 cachefiles_flush_reqs(___cache); \
436} while (0)
437
438#define cachefiles_io_error_obj(object, FMT, ...) \
439do { \
440 struct cachefiles_cache *___cache; \
441 \
442 ___cache = (object)->volume->cache; \
443 cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
444 (object)->debug_id); \
445} while (0)
446
447
448/*
449 * Debug tracing
450 */
451extern unsigned cachefiles_debug;
452#define CACHEFILES_DEBUG_KENTER 1
453#define CACHEFILES_DEBUG_KLEAVE 2
454#define CACHEFILES_DEBUG_KDEBUG 4
455
456#define dbgprintk(FMT, ...) \
457 printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
458
459#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
460#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
461#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
462
463
464#if defined(__KDEBUG)
465#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
466#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
467#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
468
469#elif defined(CONFIG_CACHEFILES_DEBUG)
470#define _enter(FMT, ...) \
471do { \
472 if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
473 kenter(FMT, ##__VA_ARGS__); \
474} while (0)
475
476#define _leave(FMT, ...) \
477do { \
478 if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
479 kleave(FMT, ##__VA_ARGS__); \
480} while (0)
481
482#define _debug(FMT, ...) \
483do { \
484 if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
485 kdebug(FMT, ##__VA_ARGS__); \
486} while (0)
487
488#else
489#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
490#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
491#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
492#endif
493
494#if 1 /* defined(__KDEBUGALL) */
495
496#define ASSERT(X) \
497do { \
498 if (unlikely(!(X))) { \
499 pr_err("\n"); \
500 pr_err("Assertion failed\n"); \
501 BUG(); \
502 } \
503} while (0)
504
505#define ASSERTCMP(X, OP, Y) \
506do { \
507 if (unlikely(!((X) OP (Y)))) { \
508 pr_err("\n"); \
509 pr_err("Assertion failed\n"); \
510 pr_err("%lx " #OP " %lx is false\n", \
511 (unsigned long)(X), (unsigned long)(Y)); \
512 BUG(); \
513 } \
514} while (0)
515
516#define ASSERTIF(C, X) \
517do { \
518 if (unlikely((C) && !(X))) { \
519 pr_err("\n"); \
520 pr_err("Assertion failed\n"); \
521 BUG(); \
522 } \
523} while (0)
524
525#define ASSERTIFCMP(C, X, OP, Y) \
526do { \
527 if (unlikely((C) && !((X) OP (Y)))) { \
528 pr_err("\n"); \
529 pr_err("Assertion failed\n"); \
530 pr_err("%lx " #OP " %lx is false\n", \
531 (unsigned long)(X), (unsigned long)(Y)); \
532 BUG(); \
533 } \
534} while (0)
535
536#else
537
538#define ASSERT(X) do {} while (0)
539#define ASSERTCMP(X, OP, Y) do {} while (0)
540#define ASSERTIF(C, X) do {} while (0)
541#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
542
543#endif