fs/sdcardfs/sdcardfs.h

   1 /*
   2  * fs/sdcardfs/sdcardfs.h
   3  *
   4  * The sdcardfs v2.0
   5  *   This file system replaces the sdcard daemon on Android
   6  *   On version 2.0, some of the daemon functions have been ported
   7  *   to support the multi-user concepts of Android 4.4
   8  *
   9  * Copyright (c) 2013 Samsung Electronics Co. Ltd
  10  *   Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
  11  *               Sunghwan Yun, Sungjong Seo
  12  *
  13  * This program has been developed as a stackable file system based on
  14  * the WrapFS which written by
  15  *
  16  * Copyright (c) 1998-2011 Erez Zadok
  17  * Copyright (c) 2009     Shrikar Archak
  18  * Copyright (c) 2003-2011 Stony Brook University
  19  * Copyright (c) 2003-2011 The Research Foundation of SUNY
  20  *
  21  * This file is dual licensed.  It may be redistributed and/or modified
  22  * under the terms of the Apache 2.0 License OR version 2 of the GNU
  23  * General Public License.
  24  */
  25
  26 #ifndef _SDCARDFS_H_
  27 #define _SDCARDFS_H_
  28
  29 #include <linux/dcache.h>
  30 #include <linux/file.h>
  31 #include <linux/fs.h>
  32 #include <linux/aio.h>
  33 #include <linux/mm.h>
  34 #include <linux/mount.h>
  35 #include <linux/namei.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/statfs.h>
  38 #include <linux/fs_stack.h>
  39 #include <linux/magic.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/slab.h>
  42 #include <linux/sched.h>
  43 #include <linux/types.h>
  44 #include <linux/security.h>
  45 #include <linux/string.h>
  46 #include <linux/list.h>
  47 #include "multiuser.h"
  48
  49 /* the file system name */
  50 #define SDCARDFS_NAME "sdcardfs"
  51
  52 /* sdcardfs root inode number */
  53 #define SDCARDFS_ROOT_INO     1
  54
  55 /* useful for tracking code reachability */
  56 #define UDBG printk(KERN_DEFAULT "DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
  57
  58 #define SDCARDFS_DIRENT_SIZE 256
  59
  60 /* temporary static uid settings for development */
  61 #define AID_ROOT             0  /* uid for accessing /mnt/sdcard & extSdcard */
  62 #define AID_MEDIA_RW      1023  /* internal media storage write access */
  63
  64 #define AID_SDCARD_RW     1015  /* external storage write access */
  65 #define AID_SDCARD_R      1028  /* external storage read access */
  66 #define AID_SDCARD_PICS   1033  /* external storage photos access */
  67 #define AID_SDCARD_AV     1034  /* external storage audio/video access */
  68 #define AID_SDCARD_ALL    1035  /* access all users external storage */
  69 #define AID_MEDIA_OBB     1059  /* obb files */
  70
  71 #define AID_SDCARD_IMAGE  1057
  72
  73 #define AID_PACKAGE_INFO  1027
  74
  75
  76 /*
  77  * Permissions are handled by our permission function.
  78  * We don't want anyone who happens to look at our inode value to prematurely
  79  * block access, so store more permissive values. These are probably never
  80  * used.
  81  */
  82 #define fixup_tmp_permissions(x)        \
  83         do {                                            \
  84                 (x)->i_uid = SDCARDFS_I(x)->d_uid;      \
  85                 (x)->i_gid = AID_SDCARD_RW;     \
  86                 (x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
  87         } while (0)
  88
  89 /* OVERRIDE_CRED() and REVERT_CRED()
  90  *      OVERRID_CRED()
  91  *              backup original task->cred
  92  *              and modifies task->cred->fsuid/fsgid to specified value.
  93  *      REVERT_CRED()
  94  *              restore original task->cred->fsuid/fsgid.
  95  * These two macro should be used in pair, and OVERRIDE_CRED() should be
  96  * placed at the beginning of a function, right after variable declaration.
  97  */
  98 #define OVERRIDE_CRED(sdcardfs_sbi, saved_cred, info)           \
  99         saved_cred = override_fsids(sdcardfs_sbi, info);        \
 100         if (!saved_cred) { return -ENOMEM; }
 101
 102 #define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred, info)       \
 103         saved_cred = override_fsids(sdcardfs_sbi, info);        \
 104         if (!saved_cred) { return ERR_PTR(-ENOMEM); }
 105
 106 #define REVERT_CRED(saved_cred) revert_fsids(saved_cred)
 107
 108 #define DEBUG_CRED()            \
 109         printk("KAKJAGI: %s:%d fsuid %d fsgid %d\n",    \
 110                 __FUNCTION__, __LINE__,                 \
 111                 (int)current->cred->fsuid,              \
 112                 (int)current->cred->fsgid);
 113
 114 /* Android 5.0 support */
 115
 116 /* Permission mode for a specific node. Controls how file permissions
 117  * are derived for children nodes. */
 118 typedef enum {
 119     /* Nothing special; this node should just inherit from its parent. */
 120     PERM_INHERIT,
 121     /* This node is one level above a normal root; used for legacy layouts
 122      * which use the first level to represent user_id. */
 123     PERM_PRE_ROOT,
 124     /* This node is "/" */
 125     PERM_ROOT,
 126     /* This node is "/Android" */
 127     PERM_ANDROID,
 128     /* This node is "/Android/data" */
 129     PERM_ANDROID_DATA,
 130     /* This node is "/Android/obb" */
 131     PERM_ANDROID_OBB,
 132     /* This node is "/Android/media" */
 133     PERM_ANDROID_MEDIA,
 134     /* This node is "/Android/[data|media|obb]/[package]" */
 135     PERM_ANDROID_PACKAGE,
 136     /* This node is "/Android/[data|media|obb]/[package]/cache" */
 137     PERM_ANDROID_PACKAGE_CACHE,
 138 } perm_t;
 139
 140 struct sdcardfs_sb_info;
 141 struct sdcardfs_mount_options;
 142 struct sdcardfs_inode_info;
 143
 144 /* Do not directly use this function. Use OVERRIDE_CRED() instead. */
 145 const struct cred * override_fsids(struct sdcardfs_sb_info* sbi, struct sdcardfs_inode_info *info);
 146 /* Do not directly use this function, use REVERT_CRED() instead. */
 147 void revert_fsids(const struct cred * old_cred);
 148
 149 /* operations vectors defined in specific files */
 150 extern const struct file_operations sdcardfs_main_fops;
 151 extern const struct file_operations sdcardfs_dir_fops;
 152 extern const struct inode_operations sdcardfs_main_iops;
 153 extern const struct inode_operations sdcardfs_dir_iops;
 154 extern const struct inode_operations sdcardfs_symlink_iops;
 155 extern const struct super_operations sdcardfs_sops;
 156 extern const struct dentry_operations sdcardfs_ci_dops;
 157 extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
 158 extern const struct vm_operations_struct sdcardfs_vm_ops;
 159
 160 extern int sdcardfs_init_inode_cache(void);
 161 extern void sdcardfs_destroy_inode_cache(void);
 162 extern int sdcardfs_init_dentry_cache(void);
 163 extern void sdcardfs_destroy_dentry_cache(void);
 164 extern int new_dentry_private_data(struct dentry *dentry);
 165 extern void free_dentry_private_data(struct dentry *dentry);
 166 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
 167                                 unsigned int flags);
 168 extern struct inode *sdcardfs_iget(struct super_block *sb,
 169                                  struct inode *lower_inode, userid_t id);
 170 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
 171                             struct path *lower_path, userid_t id);
 172
 173 /* file private data */
 174 struct sdcardfs_file_info {
 175         struct file *lower_file;
 176         const struct vm_operations_struct *lower_vm_ops;
 177 };
 178
 179 /* sdcardfs inode data in memory */
 180 struct sdcardfs_inode_info {
 181         struct inode *lower_inode;
 182         /* state derived based on current position in hierachy */
 183         perm_t perm;
 184         userid_t userid;
 185         uid_t d_uid;
 186         bool under_android;
 187         bool under_cache;
 188         bool under_obb;
 189         /* top folder for ownership */
 190         struct inode *top;
 191
 192         struct inode vfs_inode;
 193 };
 194
 195
 196 /* sdcardfs dentry data in memory */
 197 struct sdcardfs_dentry_info {
 198         spinlock_t lock;        /* protects lower_path */
 199         struct path lower_path;
 200         struct path orig_path;
 201 };
 202
 203 struct sdcardfs_mount_options {
 204         uid_t fs_low_uid;
 205         gid_t fs_low_gid;
 206         userid_t fs_user_id;
 207         bool multiuser;
 208         unsigned int reserved_mb;
 209 };
 210
 211 struct sdcardfs_vfsmount_options {
 212         gid_t gid;
 213         mode_t mask;
 214 };
 215
 216 extern int parse_options_remount(struct super_block *sb, char *options, int silent,
 217                 struct sdcardfs_vfsmount_options *vfsopts);
 218
 219 /* sdcardfs super-block data in memory */
 220 struct sdcardfs_sb_info {
 221         struct super_block *sb;
 222         struct super_block *lower_sb;
 223         /* derived perm policy : some of options have been added
 224          * to sdcardfs_mount_options (Android 4.4 support) */
 225         struct sdcardfs_mount_options options;
 226         spinlock_t lock;        /* protects obbpath */
 227         char *obbpath_s;
 228         struct path obbpath;
 229         void *pkgl_id;
 230         struct list_head list;
 231 };
 232
 233 /*
 234  * inode to private data
 235  *
 236  * Since we use containers and the struct inode is _inside_ the
 237  * sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
 238  * inode pointer), return a valid non-NULL pointer.
 239  */
 240 static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
 241 {
 242         return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
 243 }
 244
 245 /* dentry to private data */
 246 #define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
 247
 248 /* superblock to private data */
 249 #define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
 250
 251 /* file to private Data */
 252 #define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
 253
 254 /* file to lower file */
 255 static inline struct file *sdcardfs_lower_file(const struct file *f)
 256 {
 257         return SDCARDFS_F(f)->lower_file;
 258 }
 259
 260 static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
 261 {
 262         SDCARDFS_F(f)->lower_file = val;
 263 }
 264
 265 /* inode to lower inode. */
 266 static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
 267 {
 268         return SDCARDFS_I(i)->lower_inode;
 269 }
 270
 271 static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
 272 {
 273         SDCARDFS_I(i)->lower_inode = val;
 274 }
 275
 276 /* superblock to lower superblock */
 277 static inline struct super_block *sdcardfs_lower_super(
 278         const struct super_block *sb)
 279 {
 280         return SDCARDFS_SB(sb)->lower_sb;
 281 }
 282
 283 static inline void sdcardfs_set_lower_super(struct super_block *sb,
 284                                           struct super_block *val)
 285 {
 286         SDCARDFS_SB(sb)->lower_sb = val;
 287 }
 288
 289 /* path based (dentry/mnt) macros */
 290 static inline void pathcpy(struct path *dst, const struct path *src)
 291 {
 292         dst->dentry = src->dentry;
 293         dst->mnt = src->mnt;
 294 }
 295
 296 /* sdcardfs_get_pname functions calls path_get()
 297  * therefore, the caller must call "proper" path_put functions
 298  */
 299 #define SDCARDFS_DENT_FUNC(pname) \
 300 static inline void sdcardfs_get_##pname(const struct dentry *dent, \
 301                                         struct path *pname) \
 302 { \
 303         spin_lock(&SDCARDFS_D(dent)->lock); \
 304         pathcpy(pname, &SDCARDFS_D(dent)->pname); \
 305         path_get(pname); \
 306         spin_unlock(&SDCARDFS_D(dent)->lock); \
 307         return; \
 308 } \
 309 static inline void sdcardfs_put_##pname(const struct dentry *dent, \
 310                                         struct path *pname) \
 311 { \
 312         path_put(pname); \
 313         return; \
 314 } \
 315 static inline void sdcardfs_set_##pname(const struct dentry *dent, \
 316                                         struct path *pname) \
 317 { \
 318         spin_lock(&SDCARDFS_D(dent)->lock); \
 319         pathcpy(&SDCARDFS_D(dent)->pname, pname); \
 320         spin_unlock(&SDCARDFS_D(dent)->lock); \
 321         return; \
 322 } \
 323 static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
 324 { \
 325         spin_lock(&SDCARDFS_D(dent)->lock); \
 326         SDCARDFS_D(dent)->pname.dentry = NULL; \
 327         SDCARDFS_D(dent)->pname.mnt = NULL; \
 328         spin_unlock(&SDCARDFS_D(dent)->lock); \
 329         return; \
 330 } \
 331 static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
 332 { \
 333         struct path pname; \
 334         spin_lock(&SDCARDFS_D(dent)->lock); \
 335         if(SDCARDFS_D(dent)->pname.dentry) { \
 336                 pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
 337                 SDCARDFS_D(dent)->pname.dentry = NULL; \
 338                 SDCARDFS_D(dent)->pname.mnt = NULL; \
 339                 spin_unlock(&SDCARDFS_D(dent)->lock); \
 340                 path_put(&pname); \
 341         } else \
 342                 spin_unlock(&SDCARDFS_D(dent)->lock); \
 343         return; \
 344 }
 345
 346 SDCARDFS_DENT_FUNC(lower_path)
 347 SDCARDFS_DENT_FUNC(orig_path)
 348
 349 static inline bool sbinfo_has_sdcard_magic(struct sdcardfs_sb_info *sbinfo)
 350 {
 351   return sbinfo && sbinfo->sb && sbinfo->sb->s_magic == SDCARDFS_SUPER_MAGIC;
 352 }
 353
 354 /* grab a refererence if we aren't linking to ourself */
 355 static inline void set_top(struct sdcardfs_inode_info *info, struct inode *top)
 356 {
 357         struct inode *old_top = NULL;
 358         BUG_ON(IS_ERR_OR_NULL(top));
 359         if (info->top && info->top != &info->vfs_inode) {
 360                 old_top = info->top;
 361         }
 362         if (top != &info->vfs_inode)
 363                 igrab(top);
 364         info->top = top;
 365         iput(old_top);
 366 }
 367
 368 static inline struct inode *grab_top(struct sdcardfs_inode_info *info)
 369 {
 370         struct inode *top = info->top;
 371         if (top) {
 372                 return igrab(top);
 373         } else {
 374                 return NULL;
 375         }
 376 }
 377
 378 static inline void release_top(struct sdcardfs_inode_info *info)
 379 {
 380         iput(info->top);
 381 }
 382
 383 static inline int get_gid(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
 384         struct sdcardfs_vfsmount_options *opts = mnt->data;
 385
 386         if (opts->gid == AID_SDCARD_RW) {
 387                 /* As an optimization, certain trusted system components only run
 388                  * as owner but operate across all users. Since we're now handing
 389                  * out the sdcard_rw GID only to trusted apps, we're okay relaxing
 390                  * the user boundary enforcement for the default view. The UIDs
 391                  * assigned to app directories are still multiuser aware. */
 392                 return AID_SDCARD_RW;
 393         } else {
 394                 return multiuser_get_uid(info->userid, opts->gid);
 395         }
 396 }
 397 static inline int get_mode(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
 398         int owner_mode;
 399         int filtered_mode;
 400         struct sdcardfs_vfsmount_options *opts = mnt->data;
 401         int visible_mode = 0775 & ~opts->mask;
 402
 403
 404         if (info->perm == PERM_PRE_ROOT) {
 405                 /* Top of multi-user view should always be visible to ensure
 406                 * secondary users can traverse inside. */
 407                 visible_mode = 0711;
 408         } else if (info->under_android) {
 409                 /* Block "other" access to Android directories, since only apps
 410                 * belonging to a specific user should be in there; we still
 411                 * leave +x open for the default view. */
 412                 if (opts->gid == AID_SDCARD_RW) {
 413                         visible_mode = visible_mode & ~0006;
 414                 } else {
 415                         visible_mode = visible_mode & ~0007;
 416                 }
 417         }
 418         owner_mode = info->lower_inode->i_mode & 0700;
 419         filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
 420         return filtered_mode;
 421 }
 422
 423 static inline int has_graft_path(const struct dentry *dent)
 424 {
 425         int ret = 0;
 426
 427         spin_lock(&SDCARDFS_D(dent)->lock);
 428         if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
 429                 ret = 1;
 430         spin_unlock(&SDCARDFS_D(dent)->lock);
 431
 432         return ret;
 433 }
 434
 435 static inline void sdcardfs_get_real_lower(const struct dentry *dent,
 436                                                 struct path *real_lower)
 437 {
 438         /* in case of a local obb dentry
 439          * the orig_path should be returned
 440          */
 441         if(has_graft_path(dent))
 442                 sdcardfs_get_orig_path(dent, real_lower);
 443         else
 444                 sdcardfs_get_lower_path(dent, real_lower);
 445 }
 446
 447 static inline void sdcardfs_put_real_lower(const struct dentry *dent,
 448                                                 struct path *real_lower)
 449 {
 450         if(has_graft_path(dent))
 451                 sdcardfs_put_orig_path(dent, real_lower);
 452         else
 453                 sdcardfs_put_lower_path(dent, real_lower);
 454 }
 455
 456 extern struct mutex sdcardfs_super_list_lock;
 457 extern struct list_head sdcardfs_super_list;
 458
 459 /* for packagelist.c */
 460 extern appid_t get_appid(const char *app_name);
 461 extern appid_t get_ext_gid(const char *app_name);
 462 extern appid_t is_excluded(const char *app_name, userid_t userid);
 463 extern int check_caller_access_to_name(struct inode *parent_node, const struct qstr* name);
 464 extern int open_flags_to_access_mode(int open_flags);
 465 extern int packagelist_init(void);
 466 extern void packagelist_exit(void);
 467
 468 /* for derived_perm.c */
 469 #define BY_NAME         (1 << 0)
 470 #define BY_USERID       (1 << 1)
 471 struct limit_search {
 472         unsigned int flags;
 473         const char *name;
 474         size_t length;
 475         userid_t userid;
 476 };
 477
 478 extern void setup_derived_state(struct inode *inode, perm_t perm, userid_t userid,
 479                         uid_t uid, bool under_android, struct inode *top);
 480 extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
 481 extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, const struct qstr *name);
 482 extern void drop_recursive(struct dentry *parent);
 483 extern void fixup_top_recursive(struct dentry *parent);
 484 extern void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit);
 485
 486 extern void update_derived_permission_lock(struct dentry *dentry);
 487 void fixup_lower_ownership(struct dentry* dentry, const char *name);
 488 extern int need_graft_path(struct dentry *dentry);
 489 extern int is_base_obbpath(struct dentry *dentry);
 490 extern int is_obbpath_invalid(struct dentry *dentry);
 491 extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
 492
 493 /* locking helpers */
 494 static inline struct dentry *lock_parent(struct dentry *dentry)
 495 {
 496         struct dentry *dir = dget_parent(dentry);
 497         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 498         return dir;
 499 }
 500
 501 static inline void unlock_dir(struct dentry *dir)
 502 {
 503         mutex_unlock(&dir->d_inode->i_mutex);
 504         dput(dir);
 505 }
 506
 507 static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
 508 {
 509         int err;
 510         struct dentry *dent;
 511         struct iattr attrs;
 512         struct path parent;
 513
 514         dent = kern_path_locked(path_s, &parent);
 515         if (IS_ERR(dent)) {
 516                 err = PTR_ERR(dent);
 517                 if (err == -EEXIST)
 518                         err = 0;
 519                 goto out_unlock;
 520         }
 521
 522         err = vfs_mkdir2(parent.mnt, parent.dentry->d_inode, dent, mode);
 523         if (err) {
 524                 if (err == -EEXIST)
 525                         err = 0;
 526                 goto out_dput;
 527         }
 528
 529         attrs.ia_uid = uid;
 530         attrs.ia_gid = gid;
 531         attrs.ia_valid = ATTR_UID | ATTR_GID;
 532         mutex_lock(&dent->d_inode->i_mutex);
 533         notify_change2(parent.mnt, dent, &attrs);
 534         mutex_unlock(&dent->d_inode->i_mutex);
 535
 536 out_dput:
 537         dput(dent);
 538
 539 out_unlock:
 540         /* parent dentry locked by lookup_create */
 541         mutex_unlock(&parent.dentry->d_inode->i_mutex);
 542         path_put(&parent);
 543         return err;
 544 }
 545
 546 /*
 547  * Return 1, if a disk has enough free space, otherwise 0.
 548  * We assume that any files can not be overwritten.
 549  */
 550 static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
 551 {
 552         int err;
 553         struct path lower_path;
 554         struct kstatfs statfs;
 555         u64 avail;
 556         struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
 557
 558         if (sbi->options.reserved_mb) {
 559                 /* Get fs stat of lower filesystem. */
 560                 sdcardfs_get_lower_path(dentry, &lower_path);
 561                 err = vfs_statfs(&lower_path, &statfs);
 562                 sdcardfs_put_lower_path(dentry, &lower_path);
 563
 564                 if (unlikely(err))
 565                         return 0;
 566
 567                 /* Invalid statfs informations. */
 568                 if (unlikely(statfs.f_bsize == 0))
 569                         return 0;
 570
 571                 /* if you are checking directory, set size to f_bsize. */
 572                 if (unlikely(dir))
 573                         size = statfs.f_bsize;
 574
 575                 /* available size */
 576                 avail = statfs.f_bavail * statfs.f_bsize;
 577
 578                 /* not enough space */
 579                 if ((u64)size > avail)
 580                         return 0;
 581
 582                 /* enough space */
 583                 if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
 584                         return 1;
 585
 586                 return 0;
 587         } else
 588                 return 1;
 589 }
 590
 591 /*
 592  * Copies attrs and maintains sdcardfs managed attrs
 593  * Since our permission check handles all special permissions, set those to be open
 594  */
 595 static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
 596 {
 597
 598         dest->i_mode = (src->i_mode  & S_IFMT) | S_IRWXU | S_IRWXG |
 599                         S_IROTH | S_IXOTH; /* 0775 */
 600         dest->i_uid = SDCARDFS_I(dest)->d_uid;
 601         dest->i_gid = AID_SDCARD_RW;
 602         dest->i_rdev = src->i_rdev;
 603         dest->i_atime = src->i_atime;
 604         dest->i_mtime = src->i_mtime;
 605         dest->i_ctime = src->i_ctime;
 606         dest->i_blkbits = src->i_blkbits;
 607         dest->i_flags = src->i_flags;
 608         set_nlink(dest, src->i_nlink);
 609 }
 610
 611 static inline bool str_case_eq(const char *s1, const char *s2)
 612 {
 613         return !strcasecmp(s1, s2);
 614 }
 615
 616 static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2)
 617 {
 618         return q1->len == q2->len && str_case_eq(q1->name, q2->name);
 619 }
 620
 621 #define QSTR_LITERAL(string) QSTR_INIT(string, sizeof(string)-1)
 622
 623 #endif  /* not _SDCARDFS_H_ */