LXR linux/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
  18struct cachefiles_cache;
  19struct cachefiles_object;
  20
  21extern 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 */
  29struct 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
  44extern struct kmem_cache *cachefiles_object_jar;
  45
  46/*
  47 * Cache files cache definition
  48 */
  49struct 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 */
  87struct 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 */
  98struct 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 */
 109struct 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 */
 118static 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 */
 127extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
 128extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
 129
 130/*
 131 * daemon.c
 132 */
 133extern const struct file_operations cachefiles_daemon_fops;
 134
 135extern int cachefiles_has_space(struct cachefiles_cache *cache,
 136                                unsigned fnr, unsigned bnr);
 137
 138/*
 139 * interface.c
 140 */
 141extern const struct fscache_cache_ops cachefiles_cache_ops;
 142
 143/*
 144 * key.c
 145 */
 146extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
 147
 148/*
 149 * namei.c
 150 */
 151extern int cachefiles_delete_object(struct cachefiles_cache *cache,
 152                                    struct cachefiles_object *object);
 153extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
 154                                     struct cachefiles_object *object,
 155                                     const char *key,
 156                                     struct cachefiles_xattr *auxdata);
 157extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 158                                               struct dentry *dir,
 159                                               const char *name);
 160
 161extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 162                           char *filename);
 163
 164extern 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
 171extern atomic_t cachefiles_lookup_histogram[HZ];
 172extern atomic_t cachefiles_mkdir_histogram[HZ];
 173extern atomic_t cachefiles_create_histogram[HZ];
 174
 175extern int __init cachefiles_proc_init(void);
 176extern void cachefiles_proc_cleanup(void);
 177static inline
 178void 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 */
 195extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
 196                                         struct page *, gfp_t);
 197extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
 198                                          struct list_head *, unsigned *,
 199                                          gfp_t);
 200extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
 201                                    gfp_t);
 202extern int cachefiles_allocate_pages(struct fscache_retrieval *,
 203                                     struct list_head *, unsigned *, gfp_t);
 204extern int cachefiles_write_page(struct fscache_storage *, struct page *);
 205extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
 206
 207/*
 208 * security.c
 209 */
 210extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 211extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 212                                               struct dentry *root,
 213                                               const struct cred **_saved_cred);
 214
 215static 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
 221static 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 */
 230extern int cachefiles_check_object_type(struct cachefiles_object *object);
 231extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
 232                                       struct cachefiles_xattr *auxdata);
 233extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
 234                                          struct cachefiles_xattr *auxdata);
 235extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
 236                                         struct cachefiles_xattr *auxdata);
 237extern 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, ...)         \
 247do {                                                    \
 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, ...)                       \
 254do {                                                                    \
 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 */
 270static inline void _dbprintk(const char *fmt, ...)
 271        __attribute__((format(printf, 1, 2)));
 272static 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, ...)                                \
 288do {                                                    \
 289        if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 290                kenter(FMT, ##__VA_ARGS__);             \
 291} while (0)
 292
 293#define _leave(FMT, ...)                                \
 294do {                                                    \
 295        if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 296                kleave(FMT, ##__VA_ARGS__);             \
 297} while (0)
 298
 299#define _debug(FMT, ...)                                \
 300do {                                                    \
 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)                                                       \
 314do {                                                                    \
 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)                                             \
 323do {                                                                    \
 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)                                                  \
 334do {                                                                    \
 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)                                        \
 343do {                                                                    \
 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
 361