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