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