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   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