fs/cachefiles/internal.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* General netfs cache on cache files internal defs
   3  *
   4  * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells ([email protected])
   6  */
   7
   8 #ifdef pr_fmt
   9 #undef pr_fmt
  10 #endif
  11
  12 #define pr_fmt(fmt) "CacheFiles: " fmt
  13
  14
  15 #include <linux/fscache-cache.h>
  16 #include <linux/cred.h>
  17 #include <linux/security.h>
  18 #include <linux/xarray.h>
  19 #include <linux/cachefiles.h>
  20
  21 #define CACHEFILES_DIO_BLOCK_SIZE 4096
  22
  23 struct cachefiles_cache;
  24 struct cachefiles_object;
  25
  26 enum cachefiles_content {
  27         /* These values are saved on disk */
  28         CACHEFILES_CONTENT_NO_DATA      = 0, /* No content stored */
  29         CACHEFILES_CONTENT_SINGLE       = 1, /* Content is monolithic, all is present */
  30         CACHEFILES_CONTENT_ALL          = 2, /* Content is all present, no map */
  31         CACHEFILES_CONTENT_BACKFS_MAP   = 3, /* Content is piecemeal, mapped through backing fs */
  32         CACHEFILES_CONTENT_DIRTY        = 4, /* Content is dirty (only seen on disk) */
  33         nr__cachefiles_content
  34 };
  35
  36 /*
  37  * Cached volume representation.
  38  */
  39 struct cachefiles_volume {
  40         struct cachefiles_cache         *cache;
  41         struct list_head                cache_link;     /* Link in cache->volumes */
  42         struct fscache_volume           *vcookie;       /* The netfs's representation */
  43         struct dentry                   *dentry;        /* The volume dentry */
  44         struct dentry                   *fanout[256];   /* Fanout subdirs */
  45 };
  46
  47 enum cachefiles_object_state {
  48         CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */
  49         CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */
  50         CACHEFILES_ONDEMAND_OBJSTATE_REOPENING, /* Object that was closed and is being reopened. */
  51         CACHEFILES_ONDEMAND_OBJSTATE_DROPPING, /* Object is being dropped. */
  52 };
  53
  54 struct cachefiles_ondemand_info {
  55         struct work_struct              ondemand_work;
  56         int                             ondemand_id;
  57         enum cachefiles_object_state    state;
  58         struct cachefiles_object        *object;
  59         spinlock_t                      lock;
  60 };
  61
  62 /*
  63  * Backing file state.
  64  */
  65 struct cachefiles_object {
  66         struct fscache_cookie           *cookie;        /* Netfs data storage object cookie */
  67         struct cachefiles_volume        *volume;        /* Cache volume that holds this object */
  68         struct list_head                cache_link;     /* Link in cache->*_list */
  69         struct file                     *file;          /* The file representing this object */
  70         char                            *d_name;        /* Backing file name */
  71         int                             debug_id;
  72         spinlock_t                      lock;
  73         refcount_t                      ref;
  74         u8                              d_name_len;     /* Length of filename */
  75         enum cachefiles_content         content_info:8; /* Info about content presence */
  76         unsigned long                   flags;
  77 #define CACHEFILES_OBJECT_USING_TMPFILE 0               /* Have an unlinked tmpfile */
  78 #ifdef CONFIG_CACHEFILES_ONDEMAND
  79         struct cachefiles_ondemand_info *ondemand;
  80 #endif
  81 };
  82
  83 #define CACHEFILES_ONDEMAND_ID_CLOSED   -1
  84
  85 /*
  86  * Cache files cache definition
  87  */
  88 struct cachefiles_cache {
  89         struct fscache_cache            *cache;         /* Cache cookie */
  90         struct vfsmount                 *mnt;           /* mountpoint holding the cache */
  91         struct dentry                   *store;         /* Directory into which live objects go */
  92         struct dentry                   *graveyard;     /* directory into which dead objects go */
  93         struct file                     *cachefilesd;   /* manager daemon handle */
  94         struct list_head                volumes;        /* List of volume objects */
  95         struct list_head                object_list;    /* List of active objects */
  96         spinlock_t                      object_list_lock; /* Lock for volumes and object_list */
  97         const struct cred               *cache_cred;    /* security override for accessing cache */
  98         struct mutex                    daemon_mutex;   /* command serialisation mutex */
  99         wait_queue_head_t               daemon_pollwq;  /* poll waitqueue for daemon */
 100         atomic_t                        gravecounter;   /* graveyard uniquifier */
 101         atomic_t                        f_released;     /* number of objects released lately */
 102         atomic_long_t                   b_released;     /* number of blocks released lately */
 103         atomic_long_t                   b_writing;      /* Number of blocks being written */
 104         unsigned                        frun_percent;   /* when to stop culling (% files) */
 105         unsigned                        fcull_percent;  /* when to start culling (% files) */
 106         unsigned                        fstop_percent;  /* when to stop allocating (% files) */
 107         unsigned                        brun_percent;   /* when to stop culling (% blocks) */
 108         unsigned                        bcull_percent;  /* when to start culling (% blocks) */
 109         unsigned                        bstop_percent;  /* when to stop allocating (% blocks) */
 110         unsigned                        bsize;          /* cache's block size */
 111         unsigned                        bshift;         /* ilog2(bsize) */
 112         uint64_t                        frun;           /* when to stop culling */
 113         uint64_t                        fcull;          /* when to start culling */
 114         uint64_t                        fstop;          /* when to stop allocating */
 115         sector_t                        brun;           /* when to stop culling */
 116         sector_t                        bcull;          /* when to start culling */
 117         sector_t                        bstop;          /* when to stop allocating */
 118         unsigned long                   flags;
 119 #define CACHEFILES_READY                0       /* T if cache prepared */
 120 #define CACHEFILES_DEAD                 1       /* T if cache dead */
 121 #define CACHEFILES_CULLING              2       /* T if cull engaged */
 122 #define CACHEFILES_STATE_CHANGED        3       /* T if state changed (poll trigger) */
 123 #define CACHEFILES_ONDEMAND_MODE        4       /* T if in on-demand read mode */
 124         char                            *rootdirname;   /* name of cache root directory */
 125         char                            *tag;           /* cache binding tag */
 126         refcount_t                      unbind_pincount;/* refcount to do daemon unbind */
 127         struct xarray                   reqs;           /* xarray of pending on-demand requests */
 128         unsigned long                   req_id_next;
 129         struct xarray                   ondemand_ids;   /* xarray for ondemand_id allocation */
 130         u32                             ondemand_id_next;
 131         u32                             msg_id_next;
 132         u32                             secid;          /* LSM security id */
 133         bool                            have_secid;     /* whether "secid" was set */
 134 };
 135
 136 static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache)
 137 {
 138         return IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND) &&
 139                 test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
 140 }
 141
 142 struct cachefiles_req {
 143         struct cachefiles_object *object;
 144         struct completion done;
 145         refcount_t ref;
 146         int error;
 147         struct cachefiles_msg msg;
 148 };
 149
 150 #define CACHEFILES_REQ_NEW      XA_MARK_1
 151
 152 #include <trace/events/cachefiles.h>
 153
 154 static inline
 155 struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
 156 {
 157         return cres->cache_priv2;
 158 }
 159
 160 static inline
 161 struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
 162 {
 163         return fscache_cres_cookie(cres)->cache_priv;
 164 }
 165
 166 /*
 167  * note change of state for daemon
 168  */
 169 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
 170 {
 171         set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
 172         wake_up_all(&cache->daemon_pollwq);
 173 }
 174
 175 /*
 176  * cache.c
 177  */
 178 extern int cachefiles_add_cache(struct cachefiles_cache *cache);
 179 extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
 180
 181 enum cachefiles_has_space_for {
 182         cachefiles_has_space_check,
 183         cachefiles_has_space_for_write,
 184         cachefiles_has_space_for_create,
 185 };
 186 extern int cachefiles_has_space(struct cachefiles_cache *cache,
 187                                 unsigned fnr, unsigned bnr,
 188                                 enum cachefiles_has_space_for reason);
 189
 190 /*
 191  * daemon.c
 192  */
 193 extern const struct file_operations cachefiles_daemon_fops;
 194 extern void cachefiles_flush_reqs(struct cachefiles_cache *cache);
 195 extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
 196 extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
 197
 198 /*
 199  * error_inject.c
 200  */
 201 #ifdef CONFIG_CACHEFILES_ERROR_INJECTION
 202 extern unsigned int cachefiles_error_injection_state;
 203 extern int cachefiles_register_error_injection(void);
 204 extern void cachefiles_unregister_error_injection(void);
 205
 206 #else
 207 #define cachefiles_error_injection_state 0
 208
 209 static inline int cachefiles_register_error_injection(void)
 210 {
 211         return 0;
 212 }
 213
 214 static inline void cachefiles_unregister_error_injection(void)
 215 {
 216 }
 217 #endif
 218
 219
 220 static inline int cachefiles_inject_read_error(void)
 221 {
 222         return cachefiles_error_injection_state & 2 ? -EIO : 0;
 223 }
 224
 225 static inline int cachefiles_inject_write_error(void)
 226 {
 227         return cachefiles_error_injection_state & 2 ? -EIO :
 228                 cachefiles_error_injection_state & 1 ? -ENOSPC :
 229                 0;
 230 }
 231
 232 static inline int cachefiles_inject_remove_error(void)
 233 {
 234         return cachefiles_error_injection_state & 2 ? -EIO : 0;
 235 }
 236
 237 /*
 238  * interface.c
 239  */
 240 extern const struct fscache_cache_ops cachefiles_cache_ops;
 241 extern void cachefiles_see_object(struct cachefiles_object *object,
 242                                   enum cachefiles_obj_ref_trace why);
 243 extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
 244                                                         enum cachefiles_obj_ref_trace why);
 245 extern void cachefiles_put_object(struct cachefiles_object *object,
 246                                   enum cachefiles_obj_ref_trace why);
 247
 248 /*
 249  * io.c
 250  */
 251 extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
 252                                        enum fscache_want_state want_state);
 253 extern int __cachefiles_prepare_write(struct cachefiles_object *object,
 254                                       struct file *file,
 255                                       loff_t *_start, size_t *_len, size_t upper_len,
 256                                       bool no_space_allocated_yet);
 257 extern int __cachefiles_write(struct cachefiles_object *object,
 258                               struct file *file,
 259                               loff_t start_pos,
 260                               struct iov_iter *iter,
 261                               netfs_io_terminated_t term_func,
 262                               void *term_func_priv);
 263
 264 /*
 265  * key.c
 266  */
 267 extern bool cachefiles_cook_key(struct cachefiles_object *object);
 268
 269 /*
 270  * main.c
 271  */
 272 extern struct kmem_cache *cachefiles_object_jar;
 273
 274 /*
 275  * namei.c
 276  */
 277 extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 278                                            struct file *file);
 279 extern int cachefiles_bury_object(struct cachefiles_cache *cache,
 280                                   struct cachefiles_object *object,
 281                                   struct dentry *dir,
 282                                   struct dentry *rep,
 283                                   enum fscache_why_object_killed why);
 284 extern int cachefiles_delete_object(struct cachefiles_object *object,
 285                                     enum fscache_why_object_killed why);
 286 extern bool cachefiles_look_up_object(struct cachefiles_object *object);
 287 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 288                                                struct dentry *dir,
 289                                                const char *name,
 290                                                bool *_is_new);
 291 extern void cachefiles_put_directory(struct dentry *dir);
 292
 293 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 294                            char *filename);
 295
 296 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
 297                                    struct dentry *dir, char *filename);
 298 extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
 299 extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
 300                                       struct cachefiles_object *object);
 301
 302 /*
 303  * ondemand.c
 304  */
 305 #ifdef CONFIG_CACHEFILES_ONDEMAND
 306 extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
 307                                         char __user *_buffer, size_t buflen);
 308
 309 extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
 310                                      char *args);
 311
 312 extern int cachefiles_ondemand_restore(struct cachefiles_cache *cache,
 313                                         char *args);
 314
 315 extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
 316 extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
 317
 318 extern int cachefiles_ondemand_read(struct cachefiles_object *object,
 319                                     loff_t pos, size_t len);
 320
 321 extern int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
 322                                         struct cachefiles_volume *volume);
 323 extern void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj);
 324
 325 #define CACHEFILES_OBJECT_STATE_FUNCS(_state, _STATE)   \
 326 static inline bool                                                              \
 327 cachefiles_ondemand_object_is_##_state(const struct cachefiles_object *object) \
 328 {                                                                                               \
 329         return object->ondemand->state == CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
 330 }                                                                                               \
 331                                                                                                 \
 332 static inline void                                                              \
 333 cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \
 334 {                                                                                               \
 335         object->ondemand->state = CACHEFILES_ONDEMAND_OBJSTATE_##_STATE; \
 336 }
 337
 338 CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);
 339 CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);
 340 CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);
 341 CACHEFILES_OBJECT_STATE_FUNCS(dropping, DROPPING);
 342
 343 static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
 344 {
 345         return cachefiles_ondemand_object_is_reopening(req->object) &&
 346                         req->msg.opcode == CACHEFILES_OP_READ;
 347 }
 348
 349 #else
 350 static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
 351                                         char __user *_buffer, size_t buflen)
 352 {
 353         return -EOPNOTSUPP;
 354 }
 355
 356 static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
 357 {
 358         return 0;
 359 }
 360
 361 static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
 362 {
 363 }
 364
 365 static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
 366                                            loff_t pos, size_t len)
 367 {
 368         return -EOPNOTSUPP;
 369 }
 370
 371 static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *obj,
 372                                                 struct cachefiles_volume *volume)
 373 {
 374         return 0;
 375 }
 376 static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)
 377 {
 378 }
 379
 380 static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)
 381 {
 382         return false;
 383 }
 384 #endif
 385
 386 /*
 387  * security.c
 388  */
 389 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 390 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 391                                                struct dentry *root,
 392                                                const struct cred **_saved_cred);
 393
 394 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
 395                                            const struct cred **_saved_cred)
 396 {
 397         *_saved_cred = override_creds(cache->cache_cred);
 398 }
 399
 400 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
 401                                          const struct cred *saved_cred)
 402 {
 403         revert_creds(saved_cred);
 404 }
 405
 406 /*
 407  * volume.c
 408  */
 409 void cachefiles_acquire_volume(struct fscache_volume *volume);
 410 void cachefiles_free_volume(struct fscache_volume *volume);
 411 void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
 412
 413 /*
 414  * xattr.c
 415  */
 416 extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
 417 extern int cachefiles_check_auxdata(struct cachefiles_object *object,
 418                                     struct file *file);
 419 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
 420                                           struct cachefiles_object *object,
 421                                           struct dentry *dentry);
 422 extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
 423 extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
 424 extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
 425
 426 /*
 427  * Error handling
 428  */
 429 #define cachefiles_io_error(___cache, FMT, ...)         \
 430 do {                                                    \
 431         pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__);   \
 432         fscache_io_error((___cache)->cache);            \
 433         set_bit(CACHEFILES_DEAD, &(___cache)->flags);   \
 434         if (cachefiles_in_ondemand_mode(___cache))      \
 435                 cachefiles_flush_reqs(___cache);        \
 436 } while (0)
 437
 438 #define cachefiles_io_error_obj(object, FMT, ...)                       \
 439 do {                                                                    \
 440         struct cachefiles_cache *___cache;                              \
 441                                                                         \
 442         ___cache = (object)->volume->cache;                             \
 443         cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__,   \
 444                             (object)->debug_id);                        \
 445 } while (0)
 446
 447
 448 /*
 449  * Debug tracing
 450  */
 451 extern unsigned cachefiles_debug;
 452 #define CACHEFILES_DEBUG_KENTER 1
 453 #define CACHEFILES_DEBUG_KLEAVE 2
 454 #define CACHEFILES_DEBUG_KDEBUG 4
 455
 456 #define dbgprintk(FMT, ...) \
 457         printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 458
 459 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 460 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 461 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
 462
 463
 464 #if defined(__KDEBUG)
 465 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 466 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 467 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
 468
 469 #elif defined(CONFIG_CACHEFILES_DEBUG)
 470 #define _enter(FMT, ...)                                \
 471 do {                                                    \
 472         if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
 473                 kenter(FMT, ##__VA_ARGS__);             \
 474 } while (0)
 475
 476 #define _leave(FMT, ...)                                \
 477 do {                                                    \
 478         if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
 479                 kleave(FMT, ##__VA_ARGS__);             \
 480 } while (0)
 481
 482 #define _debug(FMT, ...)                                \
 483 do {                                                    \
 484         if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
 485                 kdebug(FMT, ##__VA_ARGS__);             \
 486 } while (0)
 487
 488 #else
 489 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 490 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 491 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 492 #endif
 493
 494 #if 1 /* defined(__KDEBUGALL) */
 495
 496 #define ASSERT(X)                                                       \
 497 do {                                                                    \
 498         if (unlikely(!(X))) {                                           \
 499                 pr_err("\n");                                           \
 500                 pr_err("Assertion failed\n");           \
 501                 BUG();                                                  \
 502         }                                                               \
 503 } while (0)
 504
 505 #define ASSERTCMP(X, OP, Y)                                             \
 506 do {                                                                    \
 507         if (unlikely(!((X) OP (Y)))) {                                  \
 508                 pr_err("\n");                                           \
 509                 pr_err("Assertion failed\n");           \
 510                 pr_err("%lx " #OP " %lx is false\n",                    \
 511                        (unsigned long)(X), (unsigned long)(Y));         \
 512                 BUG();                                                  \
 513         }                                                               \
 514 } while (0)
 515
 516 #define ASSERTIF(C, X)                                                  \
 517 do {                                                                    \
 518         if (unlikely((C) && !(X))) {                                    \
 519                 pr_err("\n");                                           \
 520                 pr_err("Assertion failed\n");           \
 521                 BUG();                                                  \
 522         }                                                               \
 523 } while (0)
 524
 525 #define ASSERTIFCMP(C, X, OP, Y)                                        \
 526 do {                                                                    \
 527         if (unlikely((C) && !((X) OP (Y)))) {                           \
 528                 pr_err("\n");                                           \
 529                 pr_err("Assertion failed\n");           \
 530                 pr_err("%lx " #OP " %lx is false\n",                    \
 531                        (unsigned long)(X), (unsigned long)(Y));         \
 532                 BUG();                                                  \
 533         }                                                               \
 534 } while (0)
 535
 536 #else
 537
 538 #define ASSERT(X)                       do {} while (0)
 539 #define ASSERTCMP(X, OP, Y)             do {} while (0)
 540 #define ASSERTIF(C, X)                  do {} while (0)
 541 #define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
 542
 543 #endif