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
19#define CACHEFILES_DIO_BLOCK_SIZE 4096
20
21struct cachefiles_cache;
22struct cachefiles_object;
23
24enum cachefiles_content {
25	/* These values are saved on disk */
26	CACHEFILES_CONTENT_NO_DATA	= 0, /* No content stored */
27	CACHEFILES_CONTENT_SINGLE	= 1, /* Content is monolithic, all is present */
28	CACHEFILES_CONTENT_ALL		= 2, /* Content is all present, no map */
29	CACHEFILES_CONTENT_BACKFS_MAP	= 3, /* Content is piecemeal, mapped through backing fs */
30	CACHEFILES_CONTENT_DIRTY	= 4, /* Content is dirty (only seen on disk) */
31	nr__cachefiles_content
32};
33
34/*
35 * Cached volume representation.
36 */
37struct cachefiles_volume {
38	struct cachefiles_cache		*cache;
39	struct list_head		cache_link;	/* Link in cache->volumes */
40	struct fscache_volume		*vcookie;	/* The netfs's representation */
41	struct dentry			*dentry;	/* The volume dentry */
42	struct dentry			*fanout[256];	/* Fanout subdirs */
43};
44
45/*
46 * Backing file state.
47 */
48struct cachefiles_object {
49	struct fscache_cookie		*cookie;	/* Netfs data storage object cookie */
50	struct cachefiles_volume	*volume;	/* Cache volume that holds this object */
51	struct list_head		cache_link;	/* Link in cache->*_list */
52	struct file			*file;		/* The file representing this object */
53	char				*d_name;	/* Backing file name */
54	int				debug_id;
55	spinlock_t			lock;
56	refcount_t			ref;
57	u8				d_name_len;	/* Length of filename */
58	enum cachefiles_content		content_info:8;	/* Info about content presence */
59	unsigned long			flags;
60#define CACHEFILES_OBJECT_USING_TMPFILE	0		/* Have an unlinked tmpfile */
61};
62
63/*
64 * Cache files cache definition
65 */
66struct cachefiles_cache {
67	struct fscache_cache		*cache;		/* Cache cookie */
68	struct vfsmount			*mnt;		/* mountpoint holding the cache */
69	struct dentry			*store;		/* Directory into which live objects go */
70	struct dentry			*graveyard;	/* directory into which dead objects go */
71	struct file			*cachefilesd;	/* manager daemon handle */
72	struct list_head		volumes;	/* List of volume objects */
73	struct list_head		object_list;	/* List of active objects */
74	spinlock_t			object_list_lock; /* Lock for volumes and object_list */
75	const struct cred		*cache_cred;	/* security override for accessing cache */
76	struct mutex			daemon_mutex;	/* command serialisation mutex */
77	wait_queue_head_t		daemon_pollwq;	/* poll waitqueue for daemon */
78	atomic_t			gravecounter;	/* graveyard uniquifier */
79	atomic_t			f_released;	/* number of objects released lately */
80	atomic_long_t			b_released;	/* number of blocks released lately */
81	atomic_long_t			b_writing;	/* Number of blocks being written */
82	unsigned			frun_percent;	/* when to stop culling (% files) */
83	unsigned			fcull_percent;	/* when to start culling (% files) */
84	unsigned			fstop_percent;	/* when to stop allocating (% files) */
85	unsigned			brun_percent;	/* when to stop culling (% blocks) */
86	unsigned			bcull_percent;	/* when to start culling (% blocks) */
87	unsigned			bstop_percent;	/* when to stop allocating (% blocks) */
88	unsigned			bsize;		/* cache's block size */
89	unsigned			bshift;		/* min(ilog2(PAGE_SIZE / bsize), 0) */
90	uint64_t			frun;		/* when to stop culling */
91	uint64_t			fcull;		/* when to start culling */
92	uint64_t			fstop;		/* when to stop allocating */
93	sector_t			brun;		/* when to stop culling */
94	sector_t			bcull;		/* when to start culling */
95	sector_t			bstop;		/* when to stop allocating */
96	unsigned long			flags;
97#define CACHEFILES_READY		0	/* T if cache prepared */
98#define CACHEFILES_DEAD			1	/* T if cache dead */
99#define CACHEFILES_CULLING		2	/* T if cull engaged */
100#define CACHEFILES_STATE_CHANGED	3	/* T if state changed (poll trigger) */
101	char				*rootdirname;	/* name of cache root directory */
102	char				*secctx;	/* LSM security context */
103	char				*tag;		/* cache binding tag */
104};
105
106#include <trace/events/cachefiles.h>
107
108static inline
109struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
110{
111	return cres->cache_priv2;
112}
113
114static inline
115struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
116{
117	return fscache_cres_cookie(cres)->cache_priv;
118}
119
120/*
121 * note change of state for daemon
122 */
123static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
124{
125	set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
126	wake_up_all(&cache->daemon_pollwq);
127}
128
129/*
130 * cache.c
131 */
132extern int cachefiles_add_cache(struct cachefiles_cache *cache);
133extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
134
135enum cachefiles_has_space_for {
136	cachefiles_has_space_check,
137	cachefiles_has_space_for_write,
138	cachefiles_has_space_for_create,
139};
140extern int cachefiles_has_space(struct cachefiles_cache *cache,
141				unsigned fnr, unsigned bnr,
142				enum cachefiles_has_space_for reason);
143
144/*
145 * daemon.c
146 */
147extern const struct file_operations cachefiles_daemon_fops;
148
149/*
150 * error_inject.c
151 */
152#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
153extern unsigned int cachefiles_error_injection_state;
154extern int cachefiles_register_error_injection(void);
155extern void cachefiles_unregister_error_injection(void);
156
157#else
158#define cachefiles_error_injection_state 0
159
160static inline int cachefiles_register_error_injection(void)
161{
162	return 0;
163}
164
165static inline void cachefiles_unregister_error_injection(void)
166{
167}
168#endif
169
170
171static inline int cachefiles_inject_read_error(void)
172{
173	return cachefiles_error_injection_state & 2 ? -EIO : 0;
174}
175
176static inline int cachefiles_inject_write_error(void)
177{
178	return cachefiles_error_injection_state & 2 ? -EIO :
179		cachefiles_error_injection_state & 1 ? -ENOSPC :
180		0;
181}
182
183static inline int cachefiles_inject_remove_error(void)
184{
185	return cachefiles_error_injection_state & 2 ? -EIO : 0;
186}
187
188/*
189 * interface.c
190 */
191extern const struct fscache_cache_ops cachefiles_cache_ops;
192extern void cachefiles_see_object(struct cachefiles_object *object,
193				  enum cachefiles_obj_ref_trace why);
194extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
195							enum cachefiles_obj_ref_trace why);
196extern void cachefiles_put_object(struct cachefiles_object *object,
197				  enum cachefiles_obj_ref_trace why);
198
199/*
200 * io.c
201 */
202extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
203				       enum fscache_want_state want_state);
204
205/*
206 * key.c
207 */
208extern bool cachefiles_cook_key(struct cachefiles_object *object);
209
210/*
211 * main.c
212 */
213extern struct kmem_cache *cachefiles_object_jar;
214
215/*
216 * namei.c
217 */
218extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
219					   struct file *file);
220extern int cachefiles_bury_object(struct cachefiles_cache *cache,
221				  struct cachefiles_object *object,
222				  struct dentry *dir,
223				  struct dentry *rep,
224				  enum fscache_why_object_killed why);
225extern int cachefiles_delete_object(struct cachefiles_object *object,
226				    enum fscache_why_object_killed why);
227extern bool cachefiles_look_up_object(struct cachefiles_object *object);
228extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
229					       struct dentry *dir,
230					       const char *name,
231					       bool *_is_new);
232extern void cachefiles_put_directory(struct dentry *dir);
233
234extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
235			   char *filename);
236
237extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
238				   struct dentry *dir, char *filename);
239extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
240extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
241				      struct cachefiles_object *object);
242
243/*
244 * security.c
245 */
246extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
247extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
248					       struct dentry *root,
249					       const struct cred **_saved_cred);
250
251static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
252					   const struct cred **_saved_cred)
253{
254	*_saved_cred = override_creds(cache->cache_cred);
255}
256
257static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
258					 const struct cred *saved_cred)
259{
260	revert_creds(saved_cred);
261}
262
263/*
264 * volume.c
265 */
266void cachefiles_acquire_volume(struct fscache_volume *volume);
267void cachefiles_free_volume(struct fscache_volume *volume);
268void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
269
270/*
271 * xattr.c
272 */
273extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
274extern int cachefiles_check_auxdata(struct cachefiles_object *object,
275				    struct file *file);
276extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
277					  struct cachefiles_object *object,
278					  struct dentry *dentry);
279extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
280extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
281extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
282
283/*
284 * Error handling
285 */
286#define cachefiles_io_error(___cache, FMT, ...)		\
287do {							\
288	pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__);	\
289	fscache_io_error((___cache)->cache);		\
290	set_bit(CACHEFILES_DEAD, &(___cache)->flags);	\
291} while (0)
292
293#define cachefiles_io_error_obj(object, FMT, ...)			\
294do {									\
295	struct cachefiles_cache *___cache;				\
296									\
297	___cache = (object)->volume->cache;				\
298	cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__,	\
299			    (object)->debug_id);			\
300} while (0)
301
302
303/*
304 * Debug tracing
305 */
306extern unsigned cachefiles_debug;
307#define CACHEFILES_DEBUG_KENTER	1
308#define CACHEFILES_DEBUG_KLEAVE	2
309#define CACHEFILES_DEBUG_KDEBUG	4
310
311#define dbgprintk(FMT, ...) \
312	printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
313
314#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
315#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
316#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
317
318
319#if defined(__KDEBUG)
320#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
321#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
322#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
323
324#elif defined(CONFIG_CACHEFILES_DEBUG)
325#define _enter(FMT, ...)				\
326do {							\
327	if (cachefiles_debug & CACHEFILES_DEBUG_KENTER)	\
328		kenter(FMT, ##__VA_ARGS__);		\
329} while (0)
330
331#define _leave(FMT, ...)				\
332do {							\
333	if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE)	\
334		kleave(FMT, ##__VA_ARGS__);		\
335} while (0)
336
337#define _debug(FMT, ...)				\
338do {							\
339	if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG)	\
340		kdebug(FMT, ##__VA_ARGS__);		\
341} while (0)
342
343#else
344#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
345#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
346#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
347#endif
348
349#if 1 /* defined(__KDEBUGALL) */
350
351#define ASSERT(X)							\
352do {									\
353	if (unlikely(!(X))) {						\
354		pr_err("\n");						\
355		pr_err("Assertion failed\n");		\
356		BUG();							\
357	}								\
358} while (0)
359
360#define ASSERTCMP(X, OP, Y)						\
361do {									\
362	if (unlikely(!((X) OP (Y)))) {					\
363		pr_err("\n");						\
364		pr_err("Assertion failed\n");		\
365		pr_err("%lx " #OP " %lx is false\n",			\
366		       (unsigned long)(X), (unsigned long)(Y));		\
367		BUG();							\
368	}								\
369} while (0)
370
371#define ASSERTIF(C, X)							\
372do {									\
373	if (unlikely((C) && !(X))) {					\
374		pr_err("\n");						\
375		pr_err("Assertion failed\n");		\
376		BUG();							\
377	}								\
378} while (0)
379
380#define ASSERTIFCMP(C, X, OP, Y)					\
381do {									\
382	if (unlikely((C) && !((X) OP (Y)))) {				\
383		pr_err("\n");						\
384		pr_err("Assertion failed\n");		\
385		pr_err("%lx " #OP " %lx is false\n",			\
386		       (unsigned long)(X), (unsigned long)(Y));		\
387		BUG();							\
388	}								\
389} while (0)
390
391#else
392
393#define ASSERT(X)			do {} while (0)
394#define ASSERTCMP(X, OP, Y)		do {} while (0)
395#define ASSERTIF(C, X)			do {} while (0)
396#define ASSERTIFCMP(C, X, OP, Y)	do {} while (0)
397
398#endif
399