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
47/*
48 * Backing file state.
49 */
50struct 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 */
73struct 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
119static 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
125struct 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
136static inline
137struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
138{
139	return cres->cache_priv2;
140}
141
142static inline
143struct 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 */
151static 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 */
160extern int cachefiles_add_cache(struct cachefiles_cache *cache);
161extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
162
163enum cachefiles_has_space_for {
164	cachefiles_has_space_check,
165	cachefiles_has_space_for_write,
166	cachefiles_has_space_for_create,
167};
168extern 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 */
175extern const struct file_operations cachefiles_daemon_fops;
176extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
177extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
178
179/*
180 * error_inject.c
181 */
182#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
183extern unsigned int cachefiles_error_injection_state;
184extern int cachefiles_register_error_injection(void);
185extern void cachefiles_unregister_error_injection(void);
186
187#else
188#define cachefiles_error_injection_state 0
189
190static inline int cachefiles_register_error_injection(void)
191{
192	return 0;
193}
194
195static inline void cachefiles_unregister_error_injection(void)
196{
197}
198#endif
199
200
201static inline int cachefiles_inject_read_error(void)
202{
203	return cachefiles_error_injection_state & 2 ? -EIO : 0;
204}
205
206static 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
213static inline int cachefiles_inject_remove_error(void)
214{
215	return cachefiles_error_injection_state & 2 ? -EIO : 0;
216}
217
218/*
219 * interface.c
220 */
221extern const struct fscache_cache_ops cachefiles_cache_ops;
222extern void cachefiles_see_object(struct cachefiles_object *object,
223				  enum cachefiles_obj_ref_trace why);
224extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
225							enum cachefiles_obj_ref_trace why);
226extern void cachefiles_put_object(struct cachefiles_object *object,
227				  enum cachefiles_obj_ref_trace why);
228
229/*
230 * io.c
231 */
232extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
233				       enum fscache_want_state want_state);
234extern 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);
238extern 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 */
248extern bool cachefiles_cook_key(struct cachefiles_object *object);
249
250/*
251 * main.c
252 */
253extern struct kmem_cache *cachefiles_object_jar;
254
255/*
256 * namei.c
257 */
258extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
259					   struct file *file);
260extern 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);
265extern int cachefiles_delete_object(struct cachefiles_object *object,
266				    enum fscache_why_object_killed why);
267extern bool cachefiles_look_up_object(struct cachefiles_object *object);
268extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
269					       struct dentry *dir,
270					       const char *name,
271					       bool *_is_new);
272extern void cachefiles_put_directory(struct dentry *dir);
273
274extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
275			   char *filename);
276
277extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
278				   struct dentry *dir, char *filename);
279extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
280extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
281				      struct cachefiles_object *object);
282
283/*
284 * ondemand.c
285 */
286#ifdef CONFIG_CACHEFILES_ONDEMAND
287extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
288					char __user *_buffer, size_t buflen);
289
290extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
291				     char *args);
292
293extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
294extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
295
296extern int cachefiles_ondemand_read(struct cachefiles_object *object,
297				    loff_t pos, size_t len);
298
299#else
300static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
301					char __user *_buffer, size_t buflen)
302{
303	return -EOPNOTSUPP;
304}
305
306static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
307{
308	return 0;
309}
310
311static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
312{
313}
314
315static 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 */
325extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
326extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
327					       struct dentry *root,
328					       const struct cred **_saved_cred);
329
330static 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
336static 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 */
345void cachefiles_acquire_volume(struct fscache_volume *volume);
346void cachefiles_free_volume(struct fscache_volume *volume);
347void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
348
349/*
350 * xattr.c
351 */
352extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
353extern int cachefiles_check_auxdata(struct cachefiles_object *object,
354				    struct file *file);
355extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
356					  struct cachefiles_object *object,
357					  struct dentry *dentry);
358extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
359extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
360extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
361
362/*
363 * Error handling
364 */
365#define cachefiles_io_error(___cache, FMT, ...)		\
366do {							\
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, ...)			\
373do {									\
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 */
385extern 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, ...)				\
405do {							\
406	if (cachefiles_debug & CACHEFILES_DEBUG_KENTER)	\
407		kenter(FMT, ##__VA_ARGS__);		\
408} while (0)
409
410#define _leave(FMT, ...)				\
411do {							\
412	if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE)	\
413		kleave(FMT, ##__VA_ARGS__);		\
414} while (0)
415
416#define _debug(FMT, ...)				\
417do {							\
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)							\
431do {									\
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)						\
440do {									\
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)							\
451do {									\
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)					\
460do {									\
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