fs/overlayfs/overlayfs.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *
   4  * Copyright (C) 2011 Novell Inc.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/uuid.h>
   9 #include <linux/fs.h>
  10 #include <linux/fsverity.h>
  11 #include <linux/namei.h>
  12 #include <linux/posix_acl.h>
  13 #include <linux/posix_acl_xattr.h>
  14 #include "ovl_entry.h"
  15
  16 #undef pr_fmt
  17 #define pr_fmt(fmt) "overlayfs: " fmt
  18
  19 enum ovl_path_type {
  20         __OVL_PATH_UPPER        = (1 << 0),
  21         __OVL_PATH_MERGE        = (1 << 1),
  22         __OVL_PATH_ORIGIN       = (1 << 2),
  23 };
  24
  25 #define OVL_TYPE_UPPER(type)    ((type) & __OVL_PATH_UPPER)
  26 #define OVL_TYPE_MERGE(type)    ((type) & __OVL_PATH_MERGE)
  27 #define OVL_TYPE_ORIGIN(type)   ((type) & __OVL_PATH_ORIGIN)
  28
  29 #define OVL_XATTR_NAMESPACE "overlay."
  30 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
  31 #define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1)
  32 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
  33 #define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1)
  34
  35 #define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE
  36 #define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1)
  37 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX
  38 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1)
  39 #define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX
  40 #define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1)
  41
  42 enum ovl_xattr {
  43         OVL_XATTR_OPAQUE,
  44         OVL_XATTR_REDIRECT,
  45         OVL_XATTR_ORIGIN,
  46         OVL_XATTR_IMPURE,
  47         OVL_XATTR_NLINK,
  48         OVL_XATTR_UPPER,
  49         OVL_XATTR_UUID,
  50         OVL_XATTR_METACOPY,
  51         OVL_XATTR_PROTATTR,
  52         OVL_XATTR_XWHITEOUT,
  53 };
  54
  55 enum ovl_inode_flag {
  56         /* Pure upper dir that may contain non pure upper entries */
  57         OVL_IMPURE,
  58         /* Non-merge dir that may contain whiteout entries */
  59         OVL_WHITEOUTS,
  60         OVL_INDEX,
  61         OVL_UPPERDATA,
  62         /* Inode number will remain constant over copy up. */
  63         OVL_CONST_INO,
  64         OVL_HAS_DIGEST,
  65         OVL_VERIFIED_DIGEST,
  66 };
  67
  68 enum ovl_entry_flag {
  69         OVL_E_UPPER_ALIAS,
  70         OVL_E_OPAQUE,
  71         OVL_E_CONNECTED,
  72         /* Lower stack may contain xwhiteout entries */
  73         OVL_E_XWHITEOUTS,
  74 };
  75
  76 enum {
  77         OVL_REDIRECT_OFF,       /* "off" mode is never used. In effect  */
  78         OVL_REDIRECT_FOLLOW,    /* ...it translates to either "follow"  */
  79         OVL_REDIRECT_NOFOLLOW,  /* ...or "nofollow".                    */
  80         OVL_REDIRECT_ON,
  81 };
  82
  83 enum {
  84         OVL_UUID_OFF,
  85         OVL_UUID_NULL,
  86         OVL_UUID_AUTO,
  87         OVL_UUID_ON,
  88 };
  89
  90 enum {
  91         OVL_XINO_OFF,
  92         OVL_XINO_AUTO,
  93         OVL_XINO_ON,
  94 };
  95
  96 enum {
  97         OVL_VERITY_OFF,
  98         OVL_VERITY_ON,
  99         OVL_VERITY_REQUIRE,
 100 };
 101
 102 /*
 103  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
 104  * where:
 105  * origin.fh    - exported file handle of the lower file
 106  * origin.uuid  - uuid of the lower filesystem
 107  */
 108 #define OVL_FH_VERSION  0
 109 #define OVL_FH_MAGIC    0xfb
 110
 111 /* CPU byte order required for fid decoding:  */
 112 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
 113 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
 114 /* Is the real inode encoded in fid an upper inode? */
 115 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
 116
 117 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
 118                          OVL_FH_FLAG_PATH_UPPER)
 119
 120 #if defined(__LITTLE_ENDIAN)
 121 #define OVL_FH_FLAG_CPU_ENDIAN 0
 122 #elif defined(__BIG_ENDIAN)
 123 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
 124 #else
 125 #error Endianness not defined
 126 #endif
 127
 128 /* The type used to be returned by overlay exportfs for misaligned fid */
 129 #define OVL_FILEID_V0   0xfb
 130 /* The type returned by overlay exportfs for 32bit aligned fid */
 131 #define OVL_FILEID_V1   0xf8
 132
 133 /* On-disk format for "origin" file handle */
 134 struct ovl_fb {
 135         u8 version;     /* 0 */
 136         u8 magic;       /* 0xfb */
 137         u8 len;         /* size of this header + size of fid */
 138         u8 flags;       /* OVL_FH_FLAG_* */
 139         u8 type;        /* fid_type of fid */
 140         uuid_t uuid;    /* uuid of filesystem */
 141         u32 fid[];      /* file identifier should be 32bit aligned in-memory */
 142 } __packed;
 143
 144 /* In-memory and on-wire format for overlay file handle */
 145 struct ovl_fh {
 146         u8 padding[3];  /* make sure fb.fid is 32bit aligned */
 147         union {
 148                 struct ovl_fb fb;
 149                 DECLARE_FLEX_ARRAY(u8, buf);
 150         };
 151 } __packed;
 152
 153 #define OVL_FH_WIRE_OFFSET      offsetof(struct ovl_fh, fb)
 154 #define OVL_FH_LEN(fh)          (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
 155 #define OVL_FH_FID_OFFSET       (OVL_FH_WIRE_OFFSET + \
 156                                  offsetof(struct ovl_fb, fid))
 157
 158 /* On-disk format for "metacopy" xattr (if non-zero size) */
 159 struct ovl_metacopy {
 160         u8 version;     /* 0 */
 161         u8 len;         /* size of this header + used digest bytes */
 162         u8 flags;
 163         u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */
 164         u8 digest[FS_VERITY_MAX_DIGEST_SIZE];  /* Only the used part on disk */
 165 } __packed;
 166
 167 #define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy))
 168 #define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE)
 169 #define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE }
 170
 171 static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy)
 172 {
 173         if (metacopy->len < OVL_METACOPY_MIN_SIZE)
 174                 return 0;
 175         return (int)metacopy->len - OVL_METACOPY_MIN_SIZE;
 176 }
 177
 178 /* No atime modification on underlying */
 179 #define OVL_OPEN_FLAGS (O_NOATIME)
 180
 181 extern const char *const ovl_xattr_table[][2];
 182 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
 183 {
 184         return ovl_xattr_table[ox][ofs->config.userxattr];
 185 }
 186
 187 /*
 188  * When changing ownership of an upper object map the intended ownership
 189  * according to the upper layer's idmapping. When an upper mount idmaps files
 190  * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
 191  * this object will report it as being owned by id 1000 when calling stat via
 192  * the upper mount.
 193  * In order to change ownership of an object so stat reports id 1000 when
 194  * called on an idmapped upper mount the value written to disk - i.e., the
 195  * value stored in ia_*id - must 1001. The mount mapping helper will thus take
 196  * care to map 1000 to 1001.
 197  * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
 198  */
 199 static inline int ovl_do_notify_change(struct ovl_fs *ofs,
 200                                        struct dentry *upperdentry,
 201                                        struct iattr *attr)
 202 {
 203         return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
 204 }
 205
 206 static inline int ovl_do_rmdir(struct ovl_fs *ofs,
 207                                struct inode *dir, struct dentry *dentry)
 208 {
 209         int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry);
 210
 211         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
 212         return err;
 213 }
 214
 215 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
 216                                 struct dentry *dentry)
 217 {
 218         int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
 219
 220         pr_debug("unlink(%pd2) = %i\n", dentry, err);
 221         return err;
 222 }
 223
 224 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
 225                               struct inode *dir, struct dentry *new_dentry)
 226 {
 227         int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir,
 228                            new_dentry, NULL);
 229
 230         pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
 231         return err;
 232 }
 233
 234 static inline int ovl_do_create(struct ovl_fs *ofs,
 235                                 struct inode *dir, struct dentry *dentry,
 236                                 umode_t mode)
 237 {
 238         int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true);
 239
 240         pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
 241         return err;
 242 }
 243
 244 static inline int ovl_do_mkdir(struct ovl_fs *ofs,
 245                                struct inode *dir, struct dentry *dentry,
 246                                umode_t mode)
 247 {
 248         int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
 249         pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
 250         return err;
 251 }
 252
 253 static inline int ovl_do_mknod(struct ovl_fs *ofs,
 254                                struct inode *dir, struct dentry *dentry,
 255                                umode_t mode, dev_t dev)
 256 {
 257         int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev);
 258
 259         pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
 260         return err;
 261 }
 262
 263 static inline int ovl_do_symlink(struct ovl_fs *ofs,
 264                                  struct inode *dir, struct dentry *dentry,
 265                                  const char *oldname)
 266 {
 267         int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname);
 268
 269         pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 270         return err;
 271 }
 272
 273 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
 274                                       void *value, size_t size)
 275 {
 276         int err, len;
 277
 278         WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
 279
 280         err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry,
 281                                name, value, size);
 282         len = (value && err > 0) ? err : 0;
 283
 284         pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
 285                  path->dentry, name, min(len, 48), value, size, err);
 286         return err;
 287 }
 288
 289 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
 290                                          struct dentry *upperdentry,
 291                                          enum ovl_xattr ox, void *value,
 292                                          size_t size)
 293 {
 294         struct path upperpath = {
 295                 .dentry = upperdentry,
 296                 .mnt = ovl_upper_mnt(ofs),
 297         };
 298
 299         return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
 300 }
 301
 302 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
 303                                          const struct path *path,
 304                                          enum ovl_xattr ox, void *value,
 305                                          size_t size)
 306 {
 307         return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
 308 }
 309
 310 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 311                                   const char *name, const void *value,
 312                                   size_t size, int flags)
 313 {
 314         int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
 315                                value, size, flags);
 316
 317         pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
 318                  dentry, name, min((int)size, 48), value, size, flags, err);
 319         return err;
 320 }
 321
 322 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 323                                enum ovl_xattr ox, const void *value,
 324                                size_t size)
 325 {
 326         return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
 327 }
 328
 329 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
 330                                      const char *name)
 331 {
 332         int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
 333         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 334         return err;
 335 }
 336
 337 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
 338                                   enum ovl_xattr ox)
 339 {
 340         return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
 341 }
 342
 343 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
 344                                  const char *acl_name, struct posix_acl *acl)
 345 {
 346         return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl);
 347 }
 348
 349 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
 350                                     const char *acl_name)
 351 {
 352         return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name);
 353 }
 354
 355 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
 356                                 struct dentry *olddentry, struct inode *newdir,
 357                                 struct dentry *newdentry, unsigned int flags)
 358 {
 359         int err;
 360         struct renamedata rd = {
 361                 .old_mnt_idmap  = ovl_upper_mnt_idmap(ofs),
 362                 .old_dir        = olddir,
 363                 .old_dentry     = olddentry,
 364                 .new_mnt_idmap  = ovl_upper_mnt_idmap(ofs),
 365                 .new_dir        = newdir,
 366                 .new_dentry     = newdentry,
 367                 .flags          = flags,
 368         };
 369
 370         pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
 371         err = vfs_rename(&rd);
 372         if (err) {
 373                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 374                          olddentry, newdentry, err);
 375         }
 376         return err;
 377 }
 378
 379 static inline int ovl_do_whiteout(struct ovl_fs *ofs,
 380                                   struct inode *dir, struct dentry *dentry)
 381 {
 382         int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry);
 383         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 384         return err;
 385 }
 386
 387 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
 388                                           struct dentry *dentry, umode_t mode)
 389 {
 390         struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
 391         struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path,
 392                                                 mode, O_LARGEFILE | O_WRONLY,
 393                                                 current_cred());
 394         int err = PTR_ERR_OR_ZERO(file);
 395
 396         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 397         return file;
 398 }
 399
 400 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
 401                                               const char *name,
 402                                               struct dentry *base, int len)
 403 {
 404         return lookup_one(ovl_upper_mnt_idmap(ofs), name, base, len);
 405 }
 406
 407 static inline bool ovl_open_flags_need_copy_up(int flags)
 408 {
 409         if (!flags)
 410                 return false;
 411
 412         return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
 413 }
 414
 415 /* util.c */
 416 int ovl_get_write_access(struct dentry *dentry);
 417 void ovl_put_write_access(struct dentry *dentry);
 418 void ovl_start_write(struct dentry *dentry);
 419 void ovl_end_write(struct dentry *dentry);
 420 int ovl_want_write(struct dentry *dentry);
 421 void ovl_drop_write(struct dentry *dentry);
 422 struct dentry *ovl_workdir(struct dentry *dentry);
 423 const struct cred *ovl_override_creds(struct super_block *sb);
 424 void ovl_revert_creds(const struct cred *old_cred);
 425
 426 static inline const struct cred *ovl_creds(struct super_block *sb)
 427 {
 428         return OVL_FS(sb)->creator_cred;
 429 }
 430
 431 int ovl_can_decode_fh(struct super_block *sb);
 432 struct dentry *ovl_indexdir(struct super_block *sb);
 433 bool ovl_index_all(struct super_block *sb);
 434 bool ovl_verify_lower(struct super_block *sb);
 435 struct ovl_path *ovl_stack_alloc(unsigned int n);
 436 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
 437 void ovl_stack_put(struct ovl_path *stack, unsigned int n);
 438 void ovl_stack_free(struct ovl_path *stack, unsigned int n);
 439 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 440 void ovl_free_entry(struct ovl_entry *oe);
 441 bool ovl_dentry_remote(struct dentry *dentry);
 442 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
 443 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
 444                            struct ovl_entry *oe);
 445 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
 446                            struct ovl_entry *oe, unsigned int mask);
 447 bool ovl_dentry_weird(struct dentry *dentry);
 448 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 449 void ovl_path_upper(struct dentry *dentry, struct path *path);
 450 void ovl_path_lower(struct dentry *dentry, struct path *path);
 451 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
 452 struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
 453 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 454 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
 455 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 456 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 457 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
 458 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
 459 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
 460 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
 461 struct dentry *ovl_dentry_real(struct dentry *dentry);
 462 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 463 struct inode *ovl_inode_upper(struct inode *inode);
 464 struct inode *ovl_inode_lower(struct inode *inode);
 465 struct inode *ovl_inode_lowerdata(struct inode *inode);
 466 struct inode *ovl_inode_real(struct inode *inode);
 467 struct inode *ovl_inode_realdata(struct inode *inode);
 468 const char *ovl_lowerdata_redirect(struct inode *inode);
 469 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 470 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 471 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
 472 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
 473 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
 474 bool ovl_dentry_is_opaque(struct dentry *dentry);
 475 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 476 void ovl_dentry_set_opaque(struct dentry *dentry);
 477 bool ovl_dentry_has_xwhiteouts(struct dentry *dentry);
 478 void ovl_dentry_set_xwhiteouts(struct dentry *dentry);
 479 void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
 480                               const struct ovl_layer *layer);
 481 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 482 void ovl_dentry_set_upper_alias(struct dentry *dentry);
 483 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
 484 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
 485 bool ovl_has_upperdata(struct inode *inode);
 486 void ovl_set_upperdata(struct inode *inode);
 487 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 488 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 489 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 490 void ovl_dir_modified(struct dentry *dentry, bool impurity);
 491 u64 ovl_inode_version_get(struct inode *inode);
 492 bool ovl_is_whiteout(struct dentry *dentry);
 493 bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
 494 struct file *ovl_path_open(const struct path *path, int flags);
 495 int ovl_copy_up_start(struct dentry *dentry, int flags);
 496 void ovl_copy_up_end(struct dentry *dentry);
 497 bool ovl_already_copied_up(struct dentry *dentry, int flags);
 498 char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
 499                            enum ovl_xattr ox);
 500 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
 501 bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
 502 bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
 503                          const struct path *upperpath);
 504
 505 static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
 506                                          struct dentry *upperdentry)
 507 {
 508         struct path upperpath = {
 509                 .dentry = upperdentry,
 510                 .mnt = ovl_upper_mnt(ofs),
 511         };
 512         return ovl_path_is_whiteout(ofs, &upperpath);
 513 }
 514
 515 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
 516                                           struct dentry *upperdentry)
 517 {
 518         struct path upperpath = {
 519                 .dentry = upperdentry,
 520                 .mnt = ovl_upper_mnt(ofs),
 521         };
 522         return ovl_path_check_origin_xattr(ofs, &upperpath);
 523 }
 524
 525 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
 526                        enum ovl_xattr ox, const void *value, size_t size,
 527                        int xerr);
 528 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 529 bool ovl_inuse_trylock(struct dentry *dentry);
 530 void ovl_inuse_unlock(struct dentry *dentry);
 531 bool ovl_is_inuse(struct dentry *dentry);
 532 bool ovl_need_index(struct dentry *dentry);
 533 int ovl_nlink_start(struct dentry *dentry);
 534 void ovl_nlink_end(struct dentry *dentry);
 535 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 536 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path,
 537                              struct ovl_metacopy *data);
 538 int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d,
 539                            struct ovl_metacopy *metacopy);
 540 bool ovl_is_metacopy_dentry(struct dentry *dentry);
 541 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
 542 int ovl_ensure_verity_loaded(struct path *path);
 543 int ovl_get_verity_xattr(struct ovl_fs *ofs, const struct path *path,
 544                          u8 *digest_buf, int *buf_length);
 545 int ovl_validate_verity(struct ovl_fs *ofs,
 546                         struct path *metapath,
 547                         struct path *datapath);
 548 int ovl_get_verity_digest(struct ovl_fs *ofs, struct path *src,
 549                           struct ovl_metacopy *metacopy);
 550 int ovl_sync_status(struct ovl_fs *ofs);
 551
 552 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
 553 {
 554         set_bit(flag, &OVL_I(inode)->flags);
 555 }
 556
 557 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
 558 {
 559         clear_bit(flag, &OVL_I(inode)->flags);
 560 }
 561
 562 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
 563 {
 564         return test_bit(flag, &OVL_I(inode)->flags);
 565 }
 566
 567 static inline bool ovl_is_impuredir(struct super_block *sb,
 568                                     struct dentry *upperdentry)
 569 {
 570         struct ovl_fs *ofs = OVL_FS(sb);
 571         struct path upperpath = {
 572                 .dentry = upperdentry,
 573                 .mnt = ovl_upper_mnt(ofs),
 574         };
 575
 576         return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y';
 577 }
 578
 579 static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs,
 580                                          const struct path *path)
 581 {
 582         return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE);
 583 }
 584
 585 static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
 586 {
 587         return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
 588 }
 589
 590 static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
 591 {
 592         return ofs->config.redirect_mode == OVL_REDIRECT_ON;
 593 }
 594
 595 static inline bool ovl_origin_uuid(struct ovl_fs *ofs)
 596 {
 597         return ofs->config.uuid != OVL_UUID_OFF;
 598 }
 599
 600 static inline bool ovl_has_fsid(struct ovl_fs *ofs)
 601 {
 602         return ofs->config.uuid == OVL_UUID_ON ||
 603                ofs->config.uuid == OVL_UUID_AUTO;
 604 }
 605
 606 /*
 607  * With xino=auto, we do best effort to keep all inodes on same st_dev and
 608  * d_ino consistent with st_ino.
 609  * With xino=on, we do the same effort but we warn if we failed.
 610  */
 611 static inline bool ovl_xino_warn(struct ovl_fs *ofs)
 612 {
 613         return ofs->config.xino == OVL_XINO_ON;
 614 }
 615
 616 /*
 617  * To avoid regressions in existing setups with overlay lower offline changes,
 618  * we allow lower changes only if none of the new features are used.
 619  */
 620 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
 621 {
 622         return (!ofs->config.index && !ofs->config.metacopy &&
 623                 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
 624 }
 625
 626 /* All layers on same fs? */
 627 static inline bool ovl_same_fs(struct ovl_fs *ofs)
 628 {
 629         return ofs->xino_mode == 0;
 630 }
 631
 632 /* All overlay inodes have same st_dev? */
 633 static inline bool ovl_same_dev(struct ovl_fs *ofs)
 634 {
 635         return ofs->xino_mode >= 0;
 636 }
 637
 638 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
 639 {
 640         return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
 641 }
 642
 643 static inline void ovl_inode_lock(struct inode *inode)
 644 {
 645         mutex_lock(&OVL_I(inode)->lock);
 646 }
 647
 648 static inline int ovl_inode_lock_interruptible(struct inode *inode)
 649 {
 650         return mutex_lock_interruptible(&OVL_I(inode)->lock);
 651 }
 652
 653 static inline void ovl_inode_unlock(struct inode *inode)
 654 {
 655         mutex_unlock(&OVL_I(inode)->lock);
 656 }
 657
 658
 659 /* namei.c */
 660 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
 661
 662 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
 663 {
 664         if (fh_len < sizeof(struct ovl_fh))
 665                 return -EINVAL;
 666
 667         return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
 668 }
 669
 670 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
 671                                   struct vfsmount *mnt, bool connected);
 672 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 673                         struct dentry *upperdentry, struct ovl_path **stackp);
 674 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 675                       enum ovl_xattr ox, const struct ovl_fh *fh,
 676                       bool is_upper, bool set);
 677 int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
 678                             enum ovl_xattr ox, struct dentry *real,
 679                             bool is_upper, bool set);
 680 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
 681                                bool connected);
 682 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 683 int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
 684 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
 685                        struct qstr *name);
 686 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
 687 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
 688                                 struct dentry *origin, bool verify);
 689 int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
 690                   const struct ovl_layer **layer);
 691 int ovl_verify_lowerdata(struct dentry *dentry);
 692 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 693                           unsigned int flags);
 694 bool ovl_lower_positive(struct dentry *dentry);
 695
 696 static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper,
 697                                        const struct ovl_fh *fh, bool set)
 698 {
 699         return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set);
 700 }
 701
 702 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
 703                                     struct dentry *origin, bool set)
 704 {
 705         return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin,
 706                                        false, set);
 707 }
 708
 709 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
 710                                    struct dentry *upper, bool set)
 711 {
 712         return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper,
 713                                        true, set);
 714 }
 715
 716 /* readdir.c */
 717 extern const struct file_operations ovl_dir_operations;
 718 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
 719 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 720 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
 721                            struct list_head *list);
 722 void ovl_cache_free(struct list_head *list);
 723 void ovl_dir_cache_free(struct inode *inode);
 724 int ovl_check_d_type_supported(const struct path *realpath);
 725 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
 726                         struct vfsmount *mnt, struct dentry *dentry, int level);
 727 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 728
 729 /*
 730  * Can we iterate real dir directly?
 731  *
 732  * Non-merge dir may contain whiteouts from a time it was a merge upper, before
 733  * lower dir was removed under it and possibly before it was rotated from upper
 734  * to lower layer.
 735  */
 736 static inline bool ovl_dir_is_real(struct inode *dir)
 737 {
 738         return !ovl_test_flag(OVL_WHITEOUTS, dir);
 739 }
 740
 741 /* inode.c */
 742 int ovl_set_nlink_upper(struct dentry *dentry);
 743 int ovl_set_nlink_lower(struct dentry *dentry);
 744 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 745                            struct dentry *upperdentry,
 746                            unsigned int fallback);
 747 int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
 748                    int mask);
 749
 750 #ifdef CONFIG_FS_POSIX_ACL
 751 struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
 752                                  struct inode *inode, int type,
 753                                  bool rcu, bool noperm);
 754 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
 755                                                   bool rcu)
 756 {
 757         return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true);
 758 }
 759 static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
 760                                             struct dentry *dentry, int type)
 761 {
 762         return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false);
 763 }
 764 int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 765                 struct posix_acl *acl, int type);
 766 struct posix_acl *ovl_get_acl_path(const struct path *path,
 767                                    const char *acl_name, bool noperm);
 768 #else
 769 #define ovl_get_inode_acl       NULL
 770 #define ovl_get_acl             NULL
 771 #define ovl_set_acl             NULL
 772 static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
 773                                                  const char *acl_name,
 774                                                  bool noperm)
 775 {
 776         return NULL;
 777 }
 778 #endif
 779
 780 int ovl_update_time(struct inode *inode, int flags);
 781 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 782
 783 struct ovl_inode_params {
 784         struct inode *newinode;
 785         struct dentry *upperdentry;
 786         struct ovl_entry *oe;
 787         bool index;
 788         char *redirect;
 789         char *lowerdata_redirect;
 790 };
 791 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 792                     unsigned long ino, int fsid);
 793 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 794 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
 795                                bool is_upper);
 796 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
 797 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
 798 struct inode *ovl_get_inode(struct super_block *sb,
 799                             struct ovl_inode_params *oip);
 800 void ovl_copyattr(struct inode *to);
 801
 802 /* vfs inode flags copied from real to ovl inode */
 803 #define OVL_COPY_I_FLAGS_MASK   (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
 804 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
 805 #define OVL_PROT_I_FLAGS_MASK   (S_APPEND | S_IMMUTABLE)
 806
 807 /*
 808  * fileattr flags copied from lower to upper inode on copy up.
 809  * We cannot copy up immutable/append-only flags, because that would prevent
 810  * linking temp inode to upper dir, so we store them in xattr instead.
 811  */
 812 #define OVL_COPY_FS_FLAGS_MASK  (FS_SYNC_FL | FS_NOATIME_FL)
 813 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
 814 #define OVL_PROT_FS_FLAGS_MASK  (FS_APPEND_FL | FS_IMMUTABLE_FL)
 815 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
 816
 817 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
 818 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
 819                       struct fileattr *fa);
 820
 821 static inline void ovl_copyflags(struct inode *from, struct inode *to)
 822 {
 823         unsigned int mask = OVL_COPY_I_FLAGS_MASK;
 824
 825         inode_set_flags(to, from->i_flags & mask, mask);
 826 }
 827
 828 /* dir.c */
 829 extern const struct inode_operations ovl_dir_inode_operations;
 830 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
 831                              struct dentry *dentry);
 832 struct ovl_cattr {
 833         dev_t rdev;
 834         umode_t mode;
 835         const char *link;
 836         struct dentry *hardlink;
 837 };
 838
 839 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
 840
 841 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
 842                    struct dentry **newdentry, umode_t mode);
 843 struct dentry *ovl_create_real(struct ovl_fs *ofs,
 844                                struct inode *dir, struct dentry *newdentry,
 845                                struct ovl_cattr *attr);
 846 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
 847 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
 848 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
 849                                struct ovl_cattr *attr);
 850
 851 /* file.c */
 852 extern const struct file_operations ovl_file_operations;
 853 int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa);
 854 int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa);
 855 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
 856 int ovl_fileattr_set(struct mnt_idmap *idmap,
 857                      struct dentry *dentry, struct fileattr *fa);
 858 struct ovl_file;
 859 struct ovl_file *ovl_file_alloc(struct file *realfile);
 860 void ovl_file_free(struct ovl_file *of);
 861
 862 /* copy_up.c */
 863 int ovl_copy_up(struct dentry *dentry);
 864 int ovl_copy_up_with_data(struct dentry *dentry);
 865 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
 866 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
 867 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
 868 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
 869                                   bool is_upper);
 870 struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
 871 int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
 872                       struct dentry *upper);
 873
 874 /* export.c */
 875 extern const struct export_operations ovl_export_operations;
 876 extern const struct export_operations ovl_export_fid_operations;
 877
 878 /* super.c */
 879 int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
 880
 881 /* Will this overlay be forced to mount/remount ro? */
 882 static inline bool ovl_force_readonly(struct ovl_fs *ofs)
 883 {
 884         return (!ovl_upper_mnt(ofs) || !ofs->workdir);
 885 }
 886
 887 /* xattr.c */
 888
 889 const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
 890 int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 891                 struct iattr *attr);
 892 int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 893                 struct kstat *stat, u32 request_mask, unsigned int flags);
 894 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);