linux/fs/cachefiles/internal.h
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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
  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#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
  45extern struct kmem_cache *cachefiles_object_jar;
  46
  47/*
  48 * Cache files cache definition
  49 */
  50struct 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 */
  88struct 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 */
  99struct 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 */
 110struct 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 */
 119static 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 */
 128extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
 129extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
 130
 131/*
 132 * daemon.c
 133 */
 134extern const struct file_operations cachefiles_daemon_fops;
 135
 136extern int cachefiles_has_space(struct cachefiles_cache *cache,
 137                                unsigned fnr, unsigned bnr);
 138
 139/*
 140 * interface.c
 141 */
 142extern const struct fscache_cache_ops cachefiles_cache_ops;
 143
 144/*
 145 * key.c
 146 */
 147extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
 148
 149/*
 150 * namei.c
 151 */
 152extern int cachefiles_delete_object(struct cachefiles_cache *cache,
 153                                    struct cachefiles_object *object);
 154extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
 155                                     struct cachefiles_object *object,
 156                                     const char *key,
 157                                     struct cachefiles_xattr *auxdata);
 158extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 159                                               struct dentry *dir,
 160                                               const char *name);
 161
 162extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 163                           char *filename);
 164
 165extern 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
 172extern atomic_t cachefiles_lookup_histogram[HZ];
 173extern atomic_t cachefiles_mkdir_histogram[HZ];
 174extern atomic_t cachefiles_create_histogram[HZ];
 175
 176extern int __init cachefiles_proc_init(void);
 177extern void cachefiles_proc_cleanup(void);
 178static inline
 179void 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 */
 196extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
 197                                         struct page *, gfp_t);
 198extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
 199                                          struct list_head *, unsigned *,
 200                                          gfp_t);
 201extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
 202                                    gfp_t);
 203extern int cachefiles_allocate_pages(struct fscache_retrieval *,
 204                                     struct list_head *, unsigned *, gfp_t);
 205extern int cachefiles_write_page(struct fscache_storage *, struct page *);
 206extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
 207
 208/*
 209 * security.c
 210 */
 211extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 212extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 213                                               struct dentry *root,
 214                                               const struct cred **_saved_cred);
 215
 216static 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
 222static 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 */
 231extern int cachefiles_check_object_type(struct cachefiles_object *object);
 232extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
 233                                       struct cachefiles_xattr *auxdata);
 234extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
 235                                          struct cachefiles_xattr *auxdata);
 236extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
 237                                         struct cachefiles_xattr *auxdata);
 238extern 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, ...)         \
 248do {                                                    \
 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, ...)                       \
 255do {                                                                    \
 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, ...)                                \
 282do {                                                    \
 283        if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 284                kenter(FMT, ##__VA_ARGS__);             \
 285} while (0)
 286
 287#define _leave(FMT, ...)                                \
 288do {                                                    \
 289        if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 290                kleave(FMT, ##__VA_ARGS__);             \
 291} while (0)
 292
 293#define _debug(FMT, ...)                                \
 294do {                                                    \
 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#if 1 /* defined(__KDEBUGALL) */
 306
 307#define ASSERT(X)                                                       \
 308do {                                                                    \
 309        if (unlikely(!(X))) {                                           \
 310                printk(KERN_ERR "\n");                                  \
 311                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 312                BUG();                                                  \
 313        }                                                               \
 314} while (0)
 315
 316#define ASSERTCMP(X, OP, Y)                                             \
 317do {                                                                    \
 318        if (unlikely(!((X) OP (Y)))) {                                  \
 319                printk(KERN_ERR "\n");                                  \
 320                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 321                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 322                       (unsigned long)(X), (unsigned long)(Y));         \
 323                BUG();                                                  \
 324        }                                                               \
 325} while (0)
 326
 327#define ASSERTIF(C, X)                                                  \
 328do {                                                                    \
 329        if (unlikely((C) && !(X))) {                                    \
 330                printk(KERN_ERR "\n");                                  \
 331                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 332                BUG();                                                  \
 333        }                                                               \
 334} while (0)
 335
 336#define ASSERTIFCMP(C, X, OP, Y)                                        \
 337do {                                                                    \
 338        if (unlikely((C) && !((X) OP (Y)))) {                           \
 339                printk(KERN_ERR "\n");                                  \
 340                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 341                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 342                       (unsigned long)(X), (unsigned long)(Y));         \
 343                BUG();                                                  \
 344        }                                                               \
 345} while (0)
 346
 347#else
 348
 349#define ASSERT(X)                       do {} while (0)
 350#define ASSERTCMP(X, OP, Y)             do {} while (0)
 351#define ASSERTIF(C, X)                  do {} while (0)
 352#define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 353
 354#endif
 355
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