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#define cachefiles_gfp (__GFP_WAIT | __GFP_NORETRY | __GFP_NOMEMALLOC)
  27
  28/*
  29 * node records
  30 */
  31struct cachefiles_object {
  32        struct fscache_object           fscache;        /* fscache handle */
  33        struct cachefiles_lookup_data   *lookup_data;   /* cached lookup data */
  34        struct dentry                   *dentry;        /* the file/dir representing this object */
  35        struct dentry                   *backer;        /* backing file */
  36        loff_t                          i_size;         /* object size */
  37        unsigned long                   flags;
  38#define CACHEFILES_OBJECT_ACTIVE        0               /* T if marked active */
  39#define CACHEFILES_OBJECT_BURIED        1               /* T if preemptively buried */
  40        atomic_t                        usage;          /* object usage count */
  41        uint8_t                         type;           /* object type */
  42        uint8_t                         new;            /* T if object new */
  43        spinlock_t                      work_lock;
  44        struct rb_node                  active_node;    /* link in active tree (dentry is key) */
  45};
  46
  47extern struct kmem_cache *cachefiles_object_jar;
  48
  49/*
  50 * Cache files cache definition
  51 */
  52struct cachefiles_cache {
  53        struct fscache_cache            cache;          /* FS-Cache record */
  54        struct vfsmount                 *mnt;           /* mountpoint holding the cache */
  55        struct dentry                   *graveyard;     /* directory into which dead objects go */
  56        struct file                     *cachefilesd;   /* manager daemon handle */
  57        const struct cred               *cache_cred;    /* security override for accessing cache */
  58        struct mutex                    daemon_mutex;   /* command serialisation mutex */
  59        wait_queue_head_t               daemon_pollwq;  /* poll waitqueue for daemon */
  60        struct rb_root                  active_nodes;   /* active nodes (can't be culled) */
  61        rwlock_t                        active_lock;    /* lock for active_nodes */
  62        atomic_t                        gravecounter;   /* graveyard uniquifier */
  63        unsigned                        frun_percent;   /* when to stop culling (% files) */
  64        unsigned                        fcull_percent;  /* when to start culling (% files) */
  65        unsigned                        fstop_percent;  /* when to stop allocating (% files) */
  66        unsigned                        brun_percent;   /* when to stop culling (% blocks) */
  67        unsigned                        bcull_percent;  /* when to start culling (% blocks) */
  68        unsigned                        bstop_percent;  /* when to stop allocating (% blocks) */
  69        unsigned                        bsize;          /* cache's block size */
  70        unsigned                        bshift;         /* min(ilog2(PAGE_SIZE / bsize), 0) */
  71        uint64_t                        frun;           /* when to stop culling */
  72        uint64_t                        fcull;          /* when to start culling */
  73        uint64_t                        fstop;          /* when to stop allocating */
  74        sector_t                        brun;           /* when to stop culling */
  75        sector_t                        bcull;          /* when to start culling */
  76        sector_t                        bstop;          /* when to stop allocating */
  77        unsigned long                   flags;
  78#define CACHEFILES_READY                0       /* T if cache prepared */
  79#define CACHEFILES_DEAD                 1       /* T if cache dead */
  80#define CACHEFILES_CULLING              2       /* T if cull engaged */
  81#define CACHEFILES_STATE_CHANGED        3       /* T if state changed (poll trigger) */
  82        char                            *rootdirname;   /* name of cache root directory */
  83        char                            *secctx;        /* LSM security context */
  84        char                            *tag;           /* cache binding tag */
  85};
  86
  87/*
  88 * backing file read tracking
  89 */
  90struct cachefiles_one_read {
  91        wait_queue_t                    monitor;        /* link into monitored waitqueue */
  92        struct page                     *back_page;     /* backing file page we're waiting for */
  93        struct page                     *netfs_page;    /* netfs page we're going to fill */
  94        struct fscache_retrieval        *op;            /* retrieval op covering this */
  95        struct list_head                op_link;        /* link in op's todo list */
  96};
  97
  98/*
  99 * backing file write tracking
 100 */
 101struct cachefiles_one_write {
 102        struct page                     *netfs_page;    /* netfs page to copy */
 103        struct cachefiles_object        *object;
 104        struct list_head                obj_link;       /* link in object's lists */
 105        fscache_rw_complete_t           end_io_func;
 106        void                            *context;
 107};
 108
 109/*
 110 * auxiliary data xattr buffer
 111 */
 112struct cachefiles_xattr {
 113        uint16_t                        len;
 114        uint8_t                         type;
 115        uint8_t                         data[];
 116};
 117
 118/*
 119 * note change of state for daemon
 120 */
 121static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
 122{
 123        set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
 124        wake_up_all(&cache->daemon_pollwq);
 125}
 126
 127/*
 128 * bind.c
 129 */
 130extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
 131extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
 132
 133/*
 134 * daemon.c
 135 */
 136extern const struct file_operations cachefiles_daemon_fops;
 137
 138extern int cachefiles_has_space(struct cachefiles_cache *cache,
 139                                unsigned fnr, unsigned bnr);
 140
 141/*
 142 * interface.c
 143 */
 144extern const struct fscache_cache_ops cachefiles_cache_ops;
 145
 146/*
 147 * key.c
 148 */
 149extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
 150
 151/*
 152 * namei.c
 153 */
 154extern int cachefiles_delete_object(struct cachefiles_cache *cache,
 155                                    struct cachefiles_object *object);
 156extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
 157                                     struct cachefiles_object *object,
 158                                     const char *key,
 159                                     struct cachefiles_xattr *auxdata);
 160extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 161                                               struct dentry *dir,
 162                                               const char *name);
 163
 164extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 165                           char *filename);
 166
 167extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
 168                                   struct dentry *dir, char *filename);
 169
 170/*
 171 * proc.c
 172 */
 173#ifdef CONFIG_CACHEFILES_HISTOGRAM
 174extern atomic_t cachefiles_lookup_histogram[HZ];
 175extern atomic_t cachefiles_mkdir_histogram[HZ];
 176extern atomic_t cachefiles_create_histogram[HZ];
 177
 178extern int __init cachefiles_proc_init(void);
 179extern void cachefiles_proc_cleanup(void);
 180static inline
 181void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
 182{
 183        unsigned long jif = jiffies - start_jif;
 184        if (jif >= HZ)
 185                jif = HZ - 1;
 186        atomic_inc(&histogram[jif]);
 187}
 188
 189#else
 190#define cachefiles_proc_init()          (0)
 191#define cachefiles_proc_cleanup()       do {} while (0)
 192#define cachefiles_hist(hist, start_jif) do {} while (0)
 193#endif
 194
 195/*
 196 * rdwr.c
 197 */
 198extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
 199                                         struct page *, gfp_t);
 200extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
 201                                          struct list_head *, unsigned *,
 202                                          gfp_t);
 203extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
 204                                    gfp_t);
 205extern int cachefiles_allocate_pages(struct fscache_retrieval *,
 206                                     struct list_head *, unsigned *, gfp_t);
 207extern int cachefiles_write_page(struct fscache_storage *, struct page *);
 208extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
 209
 210/*
 211 * security.c
 212 */
 213extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 214extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 215                                               struct dentry *root,
 216                                               const struct cred **_saved_cred);
 217
 218static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
 219                                           const struct cred **_saved_cred)
 220{
 221        *_saved_cred = override_creds(cache->cache_cred);
 222}
 223
 224static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
 225                                         const struct cred *saved_cred)
 226{
 227        revert_creds(saved_cred);
 228}
 229
 230/*
 231 * xattr.c
 232 */
 233extern int cachefiles_check_object_type(struct cachefiles_object *object);
 234extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
 235                                       struct cachefiles_xattr *auxdata);
 236extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
 237                                          struct cachefiles_xattr *auxdata);
 238extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
 239                                         struct cachefiles_xattr *auxdata);
 240extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
 241                                          struct dentry *dentry);
 242
 243
 244/*
 245 * error handling
 246 */
 247#define kerror(FMT, ...) printk(KERN_ERR "CacheFiles: "FMT"\n", ##__VA_ARGS__)
 248
 249#define cachefiles_io_error(___cache, FMT, ...)         \
 250do {                                                    \
 251        kerror("I/O Error: " FMT, ##__VA_ARGS__);       \
 252        fscache_io_error(&(___cache)->cache);           \
 253        set_bit(CACHEFILES_DEAD, &(___cache)->flags);   \
 254} while (0)
 255
 256#define cachefiles_io_error_obj(object, FMT, ...)                       \
 257do {                                                                    \
 258        struct cachefiles_cache *___cache;                              \
 259                                                                        \
 260        ___cache = container_of((object)->fscache.cache,                \
 261                                struct cachefiles_cache, cache);        \
 262        cachefiles_io_error(___cache, FMT, ##__VA_ARGS__);              \
 263} while (0)
 264
 265
 266/*
 267 * debug tracing
 268 */
 269#define dbgprintk(FMT, ...) \
 270        printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 271
 272#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 273#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 274#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 275
 276
 277#if defined(__KDEBUG)
 278#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 279#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 280#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 281
 282#elif defined(CONFIG_CACHEFILES_DEBUG)
 283#define _enter(FMT, ...)                                \
 284do {                                                    \
 285        if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 286                kenter(FMT, ##__VA_ARGS__);             \
 287} while (0)
 288
 289#define _leave(FMT, ...)                                \
 290do {                                                    \
 291        if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 292                kleave(FMT, ##__VA_ARGS__);             \
 293} while (0)
 294
 295#define _debug(FMT, ...)                                \
 296do {                                                    \
 297        if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
 298                kdebug(FMT, ##__VA_ARGS__);             \
 299} while (0)
 300
 301#else
 302#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 303#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 304#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 305#endif
 306
 307#if 1 /* defined(__KDEBUGALL) */
 308
 309#define ASSERT(X)                                                       \
 310do {                                                                    \
 311        if (unlikely(!(X))) {                                           \
 312                printk(KERN_ERR "\n");                                  \
 313                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 314                BUG();                                                  \
 315        }                                                               \
 316} while (0)
 317
 318#define ASSERTCMP(X, OP, Y)                                             \
 319do {                                                                    \
 320        if (unlikely(!((X) OP (Y)))) {                                  \
 321                printk(KERN_ERR "\n");                                  \
 322                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 323                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 324                       (unsigned long)(X), (unsigned long)(Y));         \
 325                BUG();                                                  \
 326        }                                                               \
 327} while (0)
 328
 329#define ASSERTIF(C, X)                                                  \
 330do {                                                                    \
 331        if (unlikely((C) && !(X))) {                                    \
 332                printk(KERN_ERR "\n");                                  \
 333                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 334                BUG();                                                  \
 335        }                                                               \
 336} while (0)
 337
 338#define ASSERTIFCMP(C, X, OP, Y)                                        \
 339do {                                                                    \
 340        if (unlikely((C) && !((X) OP (Y)))) {                           \
 341                printk(KERN_ERR "\n");                                  \
 342                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
 343                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
 344                       (unsigned long)(X), (unsigned long)(Y));         \
 345                BUG();                                                  \
 346        }                                                               \
 347} while (0)
 348
 349#else
 350
 351#define ASSERT(X)                       do {} while (0)
 352#define ASSERTCMP(X, OP, Y)             do {} while (0)
 353#define ASSERTIF(C, X)                  do {} while (0)
 354#define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 355
 356#endif
 357
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