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