f7c255f9c624eaf3e3e71bca056e41c05ccb64f3
[linux-2.6.git] / fs / cachefiles / internal.h
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 #include <linux/fscache-cache.h>
13 #include <linux/timer.h>
14 #include <linux/wait.h>
15 #include <linux/workqueue.h>
16 #include <linux/security.h>
17
18 struct cachefiles_cache;
19 struct cachefiles_object;
20
21 extern unsigned cachefiles_debug;
22 #define CACHEFILES_DEBUG_KENTER 1
23 #define CACHEFILES_DEBUG_KLEAVE 2
24 #define CACHEFILES_DEBUG_KDEBUG 4
25
26 /*
27  * node records
28  */
29 struct cachefiles_object {
30         struct fscache_object           fscache;        /* fscache handle */
31         struct cachefiles_lookup_data   *lookup_data;   /* cached lookup data */
32         struct dentry                   *dentry;        /* the file/dir representing this object */
33         struct dentry                   *backer;        /* backing file */
34         loff_t                          i_size;         /* object size */
35         unsigned long                   flags;
36 #define CACHEFILES_OBJECT_ACTIVE        0               /* T if marked active */
37         atomic_t                        usage;          /* object usage count */
38         uint8_t                         type;           /* object type */
39         uint8_t                         new;            /* T if object new */
40         spinlock_t                      work_lock;
41         struct rb_node                  active_node;    /* link in active tree (dentry is key) */
42 };
43
44 extern struct kmem_cache *cachefiles_object_jar;
45
46 /*
47  * Cache files cache definition
48  */
49 struct cachefiles_cache {
50         struct fscache_cache            cache;          /* FS-Cache record */
51         struct vfsmount                 *mnt;           /* mountpoint holding the cache */
52         struct dentry                   *graveyard;     /* directory into which dead objects go */
53         struct file                     *cachefilesd;   /* manager daemon handle */
54         const struct cred               *cache_cred;    /* security override for accessing cache */
55         struct mutex                    daemon_mutex;   /* command serialisation mutex */
56         wait_queue_head_t               daemon_pollwq;  /* poll waitqueue for daemon */
57         struct rb_root                  active_nodes;   /* active nodes (can't be culled) */
58         rwlock_t                        active_lock;    /* lock for active_nodes */
59         atomic_t                        gravecounter;   /* graveyard uniquifier */
60         unsigned                        frun_percent;   /* when to stop culling (% files) */
61         unsigned                        fcull_percent;  /* when to start culling (% files) */
62         unsigned                        fstop_percent;  /* when to stop allocating (% files) */
63         unsigned                        brun_percent;   /* when to stop culling (% blocks) */
64         unsigned                        bcull_percent;  /* when to start culling (% blocks) */
65         unsigned                        bstop_percent;  /* when to stop allocating (% blocks) */
66         unsigned                        bsize;          /* cache's block size */
67         unsigned                        bshift;         /* min(ilog2(PAGE_SIZE / bsize), 0) */
68         uint64_t                        frun;           /* when to stop culling */
69         uint64_t                        fcull;          /* when to start culling */
70         uint64_t                        fstop;          /* when to stop allocating */
71         sector_t                        brun;           /* when to stop culling */
72         sector_t                        bcull;          /* when to start culling */
73         sector_t                        bstop;          /* when to stop allocating */
74         unsigned long                   flags;
75 #define CACHEFILES_READY                0       /* T if cache prepared */
76 #define CACHEFILES_DEAD                 1       /* T if cache dead */
77 #define CACHEFILES_CULLING              2       /* T if cull engaged */
78 #define CACHEFILES_STATE_CHANGED        3       /* T if state changed (poll trigger) */
79         char                            *rootdirname;   /* name of cache root directory */
80         char                            *secctx;        /* LSM security context */
81         char                            *tag;           /* cache binding tag */
82 };
83
84 /*
85  * backing file read tracking
86  */
87 struct cachefiles_one_read {
88         wait_queue_t                    monitor;        /* link into monitored waitqueue */
89         struct page                     *back_page;     /* backing file page we're waiting for */
90         struct page                     *netfs_page;    /* netfs page we're going to fill */
91         struct fscache_retrieval        *op;            /* retrieval op covering this */
92         struct list_head                op_link;        /* link in op's todo list */
93 };
94
95 /*
96  * backing file write tracking
97  */
98 struct cachefiles_one_write {
99         struct page                     *netfs_page;    /* netfs page to copy */
100         struct cachefiles_object        *object;
101         struct list_head                obj_link;       /* link in object's lists */
102         fscache_rw_complete_t           end_io_func;
103         void                            *context;
104 };
105
106 /*
107  * auxiliary data xattr buffer
108  */
109 struct cachefiles_xattr {
110         uint16_t                        len;
111         uint8_t                         type;
112         uint8_t                         data[];
113 };
114
115 /*
116  * note change of state for daemon
117  */
118 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
119 {
120         set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
121         wake_up_all(&cache->daemon_pollwq);
122 }
123
124 /*
125  * bind.c
126  */
127 extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
128 extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
129
130 /*
131  * daemon.c
132  */
133 extern const struct file_operations cachefiles_daemon_fops;
134
135 extern int cachefiles_has_space(struct cachefiles_cache *cache,
136                                 unsigned fnr, unsigned bnr);
137
138 /*
139  * interface.c
140  */
141 extern const struct fscache_cache_ops cachefiles_cache_ops;
142
143 /*
144  * key.c
145  */
146 extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
147
148 /*
149  * namei.c
150  */
151 extern int cachefiles_delete_object(struct cachefiles_cache *cache,
152                                     struct cachefiles_object *object);
153 extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
154                                      struct cachefiles_object *object,
155                                      const char *key,
156                                      struct cachefiles_xattr *auxdata);
157 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
158                                                struct dentry *dir,
159                                                const char *name);
160
161 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
162                            char *filename);
163
164 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
165                                    struct dentry *dir, char *filename);
166
167 /*
168  * proc.c
169  */
170 #ifdef CONFIG_CACHEFILES_HISTOGRAM
171 extern atomic_t cachefiles_lookup_histogram[HZ];
172 extern atomic_t cachefiles_mkdir_histogram[HZ];
173 extern atomic_t cachefiles_create_histogram[HZ];
174
175 extern int __init cachefiles_proc_init(void);
176 extern void cachefiles_proc_cleanup(void);
177 static inline
178 void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
179 {
180         unsigned long jif = jiffies - start_jif;
181         if (jif >= HZ)
182                 jif = HZ - 1;
183         atomic_inc(&histogram[jif]);
184 }
185
186 #else
187 #define cachefiles_proc_init()          (0)
188 #define cachefiles_proc_cleanup()       do {} while (0)
189 #define cachefiles_hist(hist, start_jif) do {} while (0)
190 #endif
191
192 /*
193  * rdwr.c
194  */
195 extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
196                                          struct page *, gfp_t);
197 extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
198                                           struct list_head *, unsigned *,
199                                           gfp_t);
200 extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
201                                     gfp_t);
202 extern int cachefiles_allocate_pages(struct fscache_retrieval *,
203                                      struct list_head *, unsigned *, gfp_t);
204 extern int cachefiles_write_page(struct fscache_storage *, struct page *);
205 extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
206
207 /*
208  * security.c
209  */
210 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
211 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
212                                                struct dentry *root,
213                                                const struct cred **_saved_cred);
214
215 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
216                                            const struct cred **_saved_cred)
217 {
218         *_saved_cred = override_creds(cache->cache_cred);
219 }
220
221 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
222                                          const struct cred *saved_cred)
223 {
224         revert_creds(saved_cred);
225 }
226
227 /*
228  * xattr.c
229  */
230 extern int cachefiles_check_object_type(struct cachefiles_object *object);
231 extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
232                                        struct cachefiles_xattr *auxdata);
233 extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
234                                           struct cachefiles_xattr *auxdata);
235 extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
236                                          struct cachefiles_xattr *auxdata);
237 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
238                                           struct dentry *dentry);
239
240
241 /*
242  * error handling
243  */
244 #define kerror(FMT, ...) printk(KERN_ERR "CacheFiles: "FMT"\n", ##__VA_ARGS__)
245
246 #define cachefiles_io_error(___cache, FMT, ...)         \
247 do {                                                    \
248         kerror("I/O Error: " FMT, ##__VA_ARGS__);       \
249         fscache_io_error(&(___cache)->cache);           \
250         set_bit(CACHEFILES_DEAD, &(___cache)->flags);   \
251 } while (0)
252
253 #define cachefiles_io_error_obj(object, FMT, ...)                       \
254 do {                                                                    \
255         struct cachefiles_cache *___cache;                              \
256                                                                         \
257         ___cache = container_of((object)->fscache.cache,                \
258                                 struct cachefiles_cache, cache);        \
259         cachefiles_io_error(___cache, FMT, ##__VA_ARGS__);              \
260 } while (0)
261
262
263 /*
264  * debug tracing
265  */
266 #define dbgprintk(FMT, ...) \
267         printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
268
269 /* make sure we maintain the format strings, even when debugging is disabled */
270 static inline void _dbprintk(const char *fmt, ...)
271         __attribute__((format(printf, 1, 2)));
272 static inline void _dbprintk(const char *fmt, ...)
273 {
274 }
275
276 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
277 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
278 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
279
280
281 #if defined(__KDEBUG)
282 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
283 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
284 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
285
286 #elif defined(CONFIG_CACHEFILES_DEBUG)
287 #define _enter(FMT, ...)                                \
288 do {                                                    \
289         if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
290                 kenter(FMT, ##__VA_ARGS__);             \
291 } while (0)
292
293 #define _leave(FMT, ...)                                \
294 do {                                                    \
295         if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
296                 kleave(FMT, ##__VA_ARGS__);             \
297 } while (0)
298
299 #define _debug(FMT, ...)                                \
300 do {                                                    \
301         if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
302                 kdebug(FMT, ##__VA_ARGS__);             \
303 } while (0)
304
305 #else
306 #define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
307 #define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
308 #define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
309 #endif
310
311 #if 1 /* defined(__KDEBUGALL) */
312
313 #define ASSERT(X)                                                       \
314 do {                                                                    \
315         if (unlikely(!(X))) {                                           \
316                 printk(KERN_ERR "\n");                                  \
317                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
318                 BUG();                                                  \
319         }                                                               \
320 } while (0)
321
322 #define ASSERTCMP(X, OP, Y)                                             \
323 do {                                                                    \
324         if (unlikely(!((X) OP (Y)))) {                                  \
325                 printk(KERN_ERR "\n");                                  \
326                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
327                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
328                        (unsigned long)(X), (unsigned long)(Y));         \
329                 BUG();                                                  \
330         }                                                               \
331 } while (0)
332
333 #define ASSERTIF(C, X)                                                  \
334 do {                                                                    \
335         if (unlikely((C) && !(X))) {                                    \
336                 printk(KERN_ERR "\n");                                  \
337                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
338                 BUG();                                                  \
339         }                                                               \
340 } while (0)
341
342 #define ASSERTIFCMP(C, X, OP, Y)                                        \
343 do {                                                                    \
344         if (unlikely((C) && !((X) OP (Y)))) {                           \
345                 printk(KERN_ERR "\n");                                  \
346                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
347                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
348                        (unsigned long)(X), (unsigned long)(Y));         \
349                 BUG();                                                  \
350         }                                                               \
351 } while (0)
352
353 #else
354
355 #define ASSERT(X)                       do {} while (0)
356 #define ASSERTCMP(X, OP, Y)             do {} while (0)
357 #define ASSERTIF(C, X)                  do {} while (0)
358 #define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
359
360 #endif