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 #ifdef pr_fmt
  13 #undef pr_fmt
  14 #endif
  15
  16 #define pr_fmt(fmt) "CacheFiles: " fmt
  17
  18
  19 #include <linux/fscache-cache.h>
  20 #include <linux/timer.h>
  21 #include <linux/wait.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/security.h>
  24
  25 struct cachefiles_cache;
  26 struct cachefiles_object;
  27
  28 extern unsigned cachefiles_debug;
  29 #define CACHEFILES_DEBUG_KENTER 1
  30 #define CACHEFILES_DEBUG_KLEAVE 2
  31 #define CACHEFILES_DEBUG_KDEBUG 4
  32
  33 #define cachefiles_gfp (__GFP_RECLAIM | __GFP_NORETRY | __GFP_NOMEMALLOC)
  34
  35 /*
  36  * node records
  37  */
  38 struct cachefiles_object {
  39         struct fscache_object           fscache;        /* fscache handle */
  40         struct cachefiles_lookup_data   *lookup_data;   /* cached lookup data */
  41         struct dentry                   *dentry;        /* the file/dir representing this object */
  42         struct dentry                   *backer;        /* backing file */
  43         loff_t                          i_size;         /* object size */
  44         unsigned long                   flags;
  45 #define CACHEFILES_OBJECT_ACTIVE        0               /* T if marked active */
  46         atomic_t                        usage;          /* object usage count */
  47         uint8_t                         type;           /* object type */
  48         uint8_t                         new;            /* T if object new */
  49         spinlock_t                      work_lock;
  50         struct rb_node                  active_node;    /* link in active tree (dentry is key) */
  51 };
  52
  53 extern struct kmem_cache *cachefiles_object_jar;
  54
  55 /*
  56  * Cache files cache definition
  57  */
  58 struct cachefiles_cache {
  59         struct fscache_cache            cache;          /* FS-Cache record */
  60         struct vfsmount                 *mnt;           /* mountpoint holding the cache */
  61         struct dentry                   *graveyard;     /* directory into which dead objects go */
  62         struct file                     *cachefilesd;   /* manager daemon handle */
  63         const struct cred               *cache_cred;    /* security override for accessing cache */
  64         struct mutex                    daemon_mutex;   /* command serialisation mutex */
  65         wait_queue_head_t               daemon_pollwq;  /* poll waitqueue for daemon */
  66         struct rb_root                  active_nodes;   /* active nodes (can't be culled) */
  67         rwlock_t                        active_lock;    /* lock for active_nodes */
  68         atomic_t                        gravecounter;   /* graveyard uniquifier */
  69         atomic_t                        f_released;     /* number of objects released lately */
  70         atomic_long_t                   b_released;     /* number of blocks released lately */
  71         unsigned                        frun_percent;   /* when to stop culling (% files) */
  72         unsigned                        fcull_percent;  /* when to start culling (% files) */
  73         unsigned                        fstop_percent;  /* when to stop allocating (% files) */
  74         unsigned                        brun_percent;   /* when to stop culling (% blocks) */
  75         unsigned                        bcull_percent;  /* when to start culling (% blocks) */
  76         unsigned                        bstop_percent;  /* when to stop allocating (% blocks) */
  77         unsigned                        bsize;          /* cache's block size */
  78         unsigned                        bshift;         /* min(ilog2(PAGE_SIZE / bsize), 0) */
  79         uint64_t                        frun;           /* when to stop culling */
  80         uint64_t                        fcull;          /* when to start culling */
  81         uint64_t                        fstop;          /* when to stop allocating */
  82         sector_t                        brun;           /* when to stop culling */
  83         sector_t                        bcull;          /* when to start culling */
  84         sector_t                        bstop;          /* when to stop allocating */
  85         unsigned long                   flags;
  86 #define CACHEFILES_READY                0       /* T if cache prepared */
  87 #define CACHEFILES_DEAD                 1       /* T if cache dead */
  88 #define CACHEFILES_CULLING              2       /* T if cull engaged */
  89 #define CACHEFILES_STATE_CHANGED        3       /* T if state changed (poll trigger) */
  90         char                            *rootdirname;   /* name of cache root directory */
  91         char                            *secctx;        /* LSM security context */
  92         char                            *tag;           /* cache binding tag */
  93 };
  94
  95 /*
  96  * backing file read tracking
  97  */
  98 struct cachefiles_one_read {
  99         wait_queue_t                    monitor;        /* link into monitored waitqueue */
 100         struct page                     *back_page;     /* backing file page we're waiting for */
 101         struct page                     *netfs_page;    /* netfs page we're going to fill */
 102         struct fscache_retrieval        *op;            /* retrieval op covering this */
 103         struct list_head                op_link;        /* link in op's todo list */
 104 };
 105
 106 /*
 107  * backing file write tracking
 108  */
 109 struct cachefiles_one_write {
 110         struct page                     *netfs_page;    /* netfs page to copy */
 111         struct cachefiles_object        *object;
 112         struct list_head                obj_link;       /* link in object's lists */
 113         fscache_rw_complete_t           end_io_func;
 114         void                            *context;
 115 };
 116
 117 /*
 118  * auxiliary data xattr buffer
 119  */
 120 struct cachefiles_xattr {
 121         uint16_t                        len;
 122         uint8_t                         type;
 123         uint8_t                         data[];
 124 };
 125
 126 /*
 127  * note change of state for daemon
 128  */
 129 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
 130 {
 131         set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
 132         wake_up_all(&cache->daemon_pollwq);
 133 }
 134
 135 /*
 136  * bind.c
 137  */
 138 extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
 139 extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
 140
 141 /*
 142  * daemon.c
 143  */
 144 extern const struct file_operations cachefiles_daemon_fops;
 145
 146 extern int cachefiles_has_space(struct cachefiles_cache *cache,
 147                                 unsigned fnr, unsigned bnr);
 148
 149 /*
 150  * interface.c
 151  */
 152 extern const struct fscache_cache_ops cachefiles_cache_ops;
 153
 154 /*
 155  * key.c
 156  */
 157 extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
 158
 159 /*
 160  * namei.c
 161  */
 162 extern void cachefiles_mark_object_inactive(struct cachefiles_cache *cache,
 163                                             struct cachefiles_object *object);
 164 extern int cachefiles_delete_object(struct cachefiles_cache *cache,
 165                                     struct cachefiles_object *object);
 166 extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
 167                                      struct cachefiles_object *object,
 168                                      const char *key,
 169                                      struct cachefiles_xattr *auxdata);
 170 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 171                                                struct dentry *dir,
 172                                                const char *name);
 173
 174 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 175                            char *filename);
 176
 177 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
 178                                    struct dentry *dir, char *filename);
 179
 180 /*
 181  * proc.c
 182  */
 183 #ifdef CONFIG_CACHEFILES_HISTOGRAM
 184 extern atomic_t cachefiles_lookup_histogram[HZ];
 185 extern atomic_t cachefiles_mkdir_histogram[HZ];
 186 extern atomic_t cachefiles_create_histogram[HZ];
 187
 188 extern int __init cachefiles_proc_init(void);
 189 extern void cachefiles_proc_cleanup(void);
 190 static inline
 191 void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
 192 {
 193         unsigned long jif = jiffies - start_jif;
 194         if (jif >= HZ)
 195                 jif = HZ - 1;
 196         atomic_inc(&histogram[jif]);
 197 }
 198
 199 #else
 200 #define cachefiles_proc_init()          (0)
 201 #define cachefiles_proc_cleanup()       do {} while (0)
 202 #define cachefiles_hist(hist, start_jif) do {} while (0)
 203 #endif
 204
 205 /*
 206  * rdwr.c
 207  */
 208 extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
 209                                          struct page *, gfp_t);
 210 extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
 211                                           struct list_head *, unsigned *,
 212                                           gfp_t);
 213 extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
 214                                     gfp_t);
 215 extern int cachefiles_allocate_pages(struct fscache_retrieval *,
 216                                      struct list_head *, unsigned *, gfp_t);
 217 extern int cachefiles_write_page(struct fscache_storage *, struct page *);
 218 extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
 219
 220 /*
 221  * security.c
 222  */
 223 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 224 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 225                                                struct dentry *root,
 226                                                const struct cred **_saved_cred);
 227
 228 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
 229                                            const struct cred **_saved_cred)
 230 {
 231         *_saved_cred = override_creds(cache->cache_cred);
 232 }
 233
 234 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
 235                                          const struct cred *saved_cred)
 236 {
 237         revert_creds(saved_cred);
 238 }
 239
 240 /*
 241  * xattr.c
 242  */
 243 extern int cachefiles_check_object_type(struct cachefiles_object *object);
 244 extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
 245                                        struct cachefiles_xattr *auxdata);
 246 extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
 247                                           struct cachefiles_xattr *auxdata);
 248 extern int cachefiles_check_auxdata(struct cachefiles_object *object);
 249 extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
 250                                          struct cachefiles_xattr *auxdata);
 251 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
 252                                           struct dentry *dentry);
 253
 254
 255 /*
 256  * error handling
 257  */
 258
 259 #define cachefiles_io_error(___cache, FMT, ...)         \
 260 do {                                                    \
 261         pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__);   \
 262         fscache_io_error(&(___cache)->cache);           \
 263         set_bit(CACHEFILES_DEAD, &(___cache)->flags);   \
 264 } while (0)
 265
 266 #define cachefiles_io_error_obj(object, FMT, ...)                       \
 267 do {                                                                    \
 268         struct cachefiles_cache *___cache;                              \
 269                                                                         \
 270         ___cache = container_of((object)->fscache.cache,                \
 271                                 struct cachefiles_cache, cache);        \
 272         cachefiles_io_error(___cache, FMT, ##__VA_ARGS__);              \
 273 } while (0)
 274
 275
 276 /*
 277  * debug tracing
 278  */
 279 #define dbgprintk(FMT, ...) \
 280         printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 281
 282 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 283 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 284 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 285
 286
 287 #if defined(__KDEBUG)
 288 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 289 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 290 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 291
 292 #elif defined(CONFIG_CACHEFILES_DEBUG)
 293 #define _enter(FMT, ...)                                \
 294 do {                                                    \
 295         if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 296                 kenter(FMT, ##__VA_ARGS__);             \
 297 } while (0)
 298
 299 #define _leave(FMT, ...)                                \
 300 do {                                                    \
 301         if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 302                 kleave(FMT, ##__VA_ARGS__);             \
 303 } while (0)
 304
 305 #define _debug(FMT, ...)                                \
 306 do {                                                    \
 307         if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
 308                 kdebug(FMT, ##__VA_ARGS__);             \
 309 } while (0)
 310
 311 #else
 312 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 313 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 314 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 315 #endif
 316
 317 #if 1 /* defined(__KDEBUGALL) */
 318
 319 #define ASSERT(X)                                                       \
 320 do {                                                                    \
 321         if (unlikely(!(X))) {                                           \
 322                 pr_err("\n");                                           \
 323                 pr_err("Assertion failed\n");           \
 324                 BUG();                                                  \
 325         }                                                               \
 326 } while (0)
 327
 328 #define ASSERTCMP(X, OP, Y)                                             \
 329 do {                                                                    \
 330         if (unlikely(!((X) OP (Y)))) {                                  \
 331                 pr_err("\n");                                           \
 332                 pr_err("Assertion failed\n");           \
 333                 pr_err("%lx " #OP " %lx is false\n",                    \
 334                        (unsigned long)(X), (unsigned long)(Y));         \
 335                 BUG();                                                  \
 336         }                                                               \
 337 } while (0)
 338
 339 #define ASSERTIF(C, X)                                                  \
 340 do {                                                                    \
 341         if (unlikely((C) && !(X))) {                                    \
 342                 pr_err("\n");                                           \
 343                 pr_err("Assertion failed\n");           \
 344                 BUG();                                                  \
 345         }                                                               \
 346 } while (0)
 347
 348 #define ASSERTIFCMP(C, X, OP, Y)                                        \
 349 do {                                                                    \
 350         if (unlikely((C) && !((X) OP (Y)))) {                           \
 351                 pr_err("\n");                                           \
 352                 pr_err("Assertion failed\n");           \
 353                 pr_err("%lx " #OP " %lx is false\n",                    \
 354                        (unsigned long)(X), (unsigned long)(Y));         \
 355                 BUG();                                                  \
 356         }                                                               \
 357 } while (0)
 358
 359 #else
 360
 361 #define ASSERT(X)                       do {} while (0)
 362 #define ASSERTCMP(X, OP, Y)             do {} while (0)
 363 #define ASSERTIF(C, X)                  do {} while (0)
 364 #define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 365
 366 #endif