1/* General netfs cache on cache files internal defs
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#ifdef pr_fmt
13#undef pr_fmt
14#endif
15
16#define pr_fmt(fmt) "CacheFiles: " fmt
17
18
19#include <linux/fscache-cache.h>
20#include <linux/timer.h>
21#include <linux/wait.h>
22#include <linux/workqueue.h>
23#include <linux/security.h>
24
25struct cachefiles_cache;
26struct cachefiles_object;
27
28extern unsigned cachefiles_debug;
29#define CACHEFILES_DEBUG_KENTER	1
30#define CACHEFILES_DEBUG_KLEAVE	2
31#define CACHEFILES_DEBUG_KDEBUG	4
32
33#define cachefiles_gfp (__GFP_WAIT | __GFP_NORETRY | __GFP_NOMEMALLOC)
34
35/*
36 * node records
37 */
38struct cachefiles_object {
39	struct fscache_object		fscache;	/* fscache handle */
40	struct cachefiles_lookup_data	*lookup_data;	/* cached lookup data */
41	struct dentry			*dentry;	/* the file/dir representing this object */
42	struct dentry			*backer;	/* backing file */
43	loff_t				i_size;		/* object size */
44	unsigned long			flags;
45#define CACHEFILES_OBJECT_ACTIVE	0		/* T if marked active */
46#define CACHEFILES_OBJECT_BURIED	1		/* T if preemptively buried */
47	atomic_t			usage;		/* object usage count */
48	uint8_t				type;		/* object type */
49	uint8_t				new;		/* T if object new */
50	spinlock_t			work_lock;
51	struct rb_node			active_node;	/* link in active tree (dentry is key) */
52};
53
54extern struct kmem_cache *cachefiles_object_jar;
55
56/*
57 * Cache files cache definition
58 */
59struct cachefiles_cache {
60	struct fscache_cache		cache;		/* FS-Cache record */
61	struct vfsmount			*mnt;		/* mountpoint holding the cache */
62	struct dentry			*graveyard;	/* directory into which dead objects go */
63	struct file			*cachefilesd;	/* manager daemon handle */
64	const struct cred		*cache_cred;	/* security override for accessing cache */
65	struct mutex			daemon_mutex;	/* command serialisation mutex */
66	wait_queue_head_t		daemon_pollwq;	/* poll waitqueue for daemon */
67	struct rb_root			active_nodes;	/* active nodes (can't be culled) */
68	rwlock_t			active_lock;	/* lock for active_nodes */
69	atomic_t			gravecounter;	/* graveyard uniquifier */
70	unsigned			frun_percent;	/* when to stop culling (% files) */
71	unsigned			fcull_percent;	/* when to start culling (% files) */
72	unsigned			fstop_percent;	/* when to stop allocating (% files) */
73	unsigned			brun_percent;	/* when to stop culling (% blocks) */
74	unsigned			bcull_percent;	/* when to start culling (% blocks) */
75	unsigned			bstop_percent;	/* when to stop allocating (% blocks) */
76	unsigned			bsize;		/* cache's block size */
77	unsigned			bshift;		/* min(ilog2(PAGE_SIZE / bsize), 0) */
78	uint64_t			frun;		/* when to stop culling */
79	uint64_t			fcull;		/* when to start culling */
80	uint64_t			fstop;		/* when to stop allocating */
81	sector_t			brun;		/* when to stop culling */
82	sector_t			bcull;		/* when to start culling */
83	sector_t			bstop;		/* when to stop allocating */
84	unsigned long			flags;
85#define CACHEFILES_READY		0	/* T if cache prepared */
86#define CACHEFILES_DEAD			1	/* T if cache dead */
87#define CACHEFILES_CULLING		2	/* T if cull engaged */
88#define CACHEFILES_STATE_CHANGED	3	/* T if state changed (poll trigger) */
89	char				*rootdirname;	/* name of cache root directory */
90	char				*secctx;	/* LSM security context */
91	char				*tag;		/* cache binding tag */
92};
93
94/*
95 * backing file read tracking
96 */
97struct cachefiles_one_read {
98	wait_queue_t			monitor;	/* link into monitored waitqueue */
99	struct page			*back_page;	/* backing file page we're waiting for */
100	struct page			*netfs_page;	/* netfs page we're going to fill */
101	struct fscache_retrieval	*op;		/* retrieval op covering this */
102	struct list_head		op_link;	/* link in op's todo list */
103};
104
105/*
106 * backing file write tracking
107 */
108struct cachefiles_one_write {
109	struct page			*netfs_page;	/* netfs page to copy */
110	struct cachefiles_object	*object;
111	struct list_head		obj_link;	/* link in object's lists */
112	fscache_rw_complete_t		end_io_func;
113	void				*context;
114};
115
116/*
117 * auxiliary data xattr buffer
118 */
119struct cachefiles_xattr {
120	uint16_t			len;
121	uint8_t				type;
122	uint8_t				data[];
123};
124
125/*
126 * note change of state for daemon
127 */
128static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
129{
130	set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
131	wake_up_all(&cache->daemon_pollwq);
132}
133
134/*
135 * bind.c
136 */
137extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
138extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
139
140/*
141 * daemon.c
142 */
143extern const struct file_operations cachefiles_daemon_fops;
144
145extern int cachefiles_has_space(struct cachefiles_cache *cache,
146				unsigned fnr, unsigned bnr);
147
148/*
149 * interface.c
150 */
151extern const struct fscache_cache_ops cachefiles_cache_ops;
152
153/*
154 * key.c
155 */
156extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
157
158/*
159 * namei.c
160 */
161extern int cachefiles_delete_object(struct cachefiles_cache *cache,
162				    struct cachefiles_object *object);
163extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
164				     struct cachefiles_object *object,
165				     const char *key,
166				     struct cachefiles_xattr *auxdata);
167extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
168					       struct dentry *dir,
169					       const char *name);
170
171extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
172			   char *filename);
173
174extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
175				   struct dentry *dir, char *filename);
176
177/*
178 * proc.c
179 */
180#ifdef CONFIG_CACHEFILES_HISTOGRAM
181extern atomic_t cachefiles_lookup_histogram[HZ];
182extern atomic_t cachefiles_mkdir_histogram[HZ];
183extern atomic_t cachefiles_create_histogram[HZ];
184
185extern int __init cachefiles_proc_init(void);
186extern void cachefiles_proc_cleanup(void);
187static inline
188void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
189{
190	unsigned long jif = jiffies - start_jif;
191	if (jif >= HZ)
192		jif = HZ - 1;
193	atomic_inc(&histogram[jif]);
194}
195
196#else
197#define cachefiles_proc_init()		(0)
198#define cachefiles_proc_cleanup()	do {} while (0)
199#define cachefiles_hist(hist, start_jif) do {} while (0)
200#endif
201
202/*
203 * rdwr.c
204 */
205extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
206					 struct page *, gfp_t);
207extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
208					  struct list_head *, unsigned *,
209					  gfp_t);
210extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
211				    gfp_t);
212extern int cachefiles_allocate_pages(struct fscache_retrieval *,
213				     struct list_head *, unsigned *, gfp_t);
214extern int cachefiles_write_page(struct fscache_storage *, struct page *);
215extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
216
217/*
218 * security.c
219 */
220extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
221extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
222					       struct dentry *root,
223					       const struct cred **_saved_cred);
224
225static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
226					   const struct cred **_saved_cred)
227{
228	*_saved_cred = override_creds(cache->cache_cred);
229}
230
231static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
232					 const struct cred *saved_cred)
233{
234	revert_creds(saved_cred);
235}
236
237/*
238 * xattr.c
239 */
240extern int cachefiles_check_object_type(struct cachefiles_object *object);
241extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
242				       struct cachefiles_xattr *auxdata);
243extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
244					  struct cachefiles_xattr *auxdata);
245extern int cachefiles_check_auxdata(struct cachefiles_object *object);
246extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
247					 struct cachefiles_xattr *auxdata);
248extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
249					  struct dentry *dentry);
250
251
252/*
253 * error handling
254 */
255
256#define cachefiles_io_error(___cache, FMT, ...)		\
257do {							\
258	pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__);	\
259	fscache_io_error(&(___cache)->cache);		\
260	set_bit(CACHEFILES_DEAD, &(___cache)->flags);	\
261} while (0)
262
263#define cachefiles_io_error_obj(object, FMT, ...)			\
264do {									\
265	struct cachefiles_cache *___cache;				\
266									\
267	___cache = container_of((object)->fscache.cache,		\
268				struct cachefiles_cache, cache);	\
269	cachefiles_io_error(___cache, FMT, ##__VA_ARGS__);		\
270} while (0)
271
272
273/*
274 * debug tracing
275 */
276#define dbgprintk(FMT, ...) \
277	printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
278
279#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
280#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
281#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
282
283
284#if defined(__KDEBUG)
285#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
286#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
287#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
288
289#elif defined(CONFIG_CACHEFILES_DEBUG)
290#define _enter(FMT, ...)				\
291do {							\
292	if (cachefiles_debug & CACHEFILES_DEBUG_KENTER)	\
293		kenter(FMT, ##__VA_ARGS__);		\
294} while (0)
295
296#define _leave(FMT, ...)				\
297do {							\
298	if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE)	\
299		kleave(FMT, ##__VA_ARGS__);		\
300} while (0)
301
302#define _debug(FMT, ...)				\
303do {							\
304	if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG)	\
305		kdebug(FMT, ##__VA_ARGS__);		\
306} while (0)
307
308#else
309#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
310#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
311#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
312#endif
313
314#if 1 /* defined(__KDEBUGALL) */
315
316#define ASSERT(X)							\
317do {									\
318	if (unlikely(!(X))) {						\
319		pr_err("\n");						\
320		pr_err("Assertion failed\n");		\
321		BUG();							\
322	}								\
323} while (0)
324
325#define ASSERTCMP(X, OP, Y)						\
326do {									\
327	if (unlikely(!((X) OP (Y)))) {					\
328		pr_err("\n");						\
329		pr_err("Assertion failed\n");		\
330		pr_err("%lx " #OP " %lx is false\n",			\
331		       (unsigned long)(X), (unsigned long)(Y));		\
332		BUG();							\
333	}								\
334} while (0)
335
336#define ASSERTIF(C, X)							\
337do {									\
338	if (unlikely((C) && !(X))) {					\
339		pr_err("\n");						\
340		pr_err("Assertion failed\n");		\
341		BUG();							\
342	}								\
343} while (0)
344
345#define ASSERTIFCMP(C, X, OP, Y)					\
346do {									\
347	if (unlikely((C) && !((X) OP (Y)))) {				\
348		pr_err("\n");						\
349		pr_err("Assertion failed\n");		\
350		pr_err("%lx " #OP " %lx is false\n",			\
351		       (unsigned long)(X), (unsigned long)(Y));		\
352		BUG();							\
353	}								\
354} while (0)
355
356#else
357
358#define ASSERT(X)			do {} while (0)
359#define ASSERTCMP(X, OP, Y)		do {} while (0)
360#define ASSERTIF(C, X)			do {} while (0)
361#define ASSERTIFCMP(C, X, OP, Y)	do {} while (0)
362
363#endif
364