release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 271 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 272 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 273
 274
 275 #if defined(__KDEBUG)
 276 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 277 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 278 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 279
 280 #elif defined(CONFIG_CACHEFILES_DEBUG)
 281 #define _enter(FMT, ...)                                \
 282 do {                                                    \
 283         if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 284                 kenter(FMT, ##__VA_ARGS__);             \
 285 } while (0)
 286
 287 #define _leave(FMT, ...)                                \
 288 do {                                                    \
 289         if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 290                 kleave(FMT, ##__VA_ARGS__);             \
 291 } while (0)
 292
 293 #define _debug(FMT, ...)                                \
 294 do {                                                    \
 295         if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
 296                 kdebug(FMT, ##__VA_ARGS__);             \
 297 } while (0)
 298
 299 #else
 300 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 301 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 302 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 303 #endif
 304
 305
 306 #define ASSERT(X)                                                       \
 307 do {                                                                    \
 308         if (unlikely(!(X))) {                                           \
 309                 printk(KERN_ERR "\n");                                  \
 310                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 311                 BUG();                                                  \
 312         }                                                               \
 313 } while (0)
 314
 315 #define ASSERTCMP(X, OP, Y)                                             \
 316 do {                                                                    \
 317         if (unlikely(!((X) OP (Y)))) {                                  \
 318                 printk(KERN_ERR "\n");                                  \
 319                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 320                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 321                        (unsigned long)(X), (unsigned long)(Y));         \
 322                 BUG();                                                  \
 323         }                                                               \
 324 } while (0)
 325
 326 #define ASSERTIF(C, X)                                                  \
 327 do {                                                                    \
 328         if (unlikely((C) && !(X))) {                                    \
 329                 printk(KERN_ERR "\n");                                  \
 330                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 331                 BUG();                                                  \
 332         }                                                               \
 333 } while (0)
 334
 335 #define ASSERTIFCMP(C, X, OP, Y)                                        \
 336 do {                                                                    \
 337         if (unlikely((C) && !((X) OP (Y)))) {                           \
 338                 printk(KERN_ERR "\n");                                  \
 339                 printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 340                 printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 341                        (unsigned long)(X), (unsigned long)(Y));         \
 342                 BUG();                                                  \
 343         }                                                               \
 344 } while (0)