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 "ovl_entry.h" 11 12#undef pr_fmt 13#define pr_fmt(fmt) "overlayfs: " fmt 14 15enum ovl_path_type { 16 __OVL_PATH_UPPER = (1 << 0), 17 __OVL_PATH_MERGE = (1 << 1), 18 __OVL_PATH_ORIGIN = (1 << 2), 19}; 20 21#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 22#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 23#define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 24 25#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay." 26 27enum ovl_xattr { 28 OVL_XATTR_OPAQUE, 29 OVL_XATTR_REDIRECT, 30 OVL_XATTR_ORIGIN, 31 OVL_XATTR_IMPURE, 32 OVL_XATTR_NLINK, 33 OVL_XATTR_UPPER, 34 OVL_XATTR_METACOPY, 35}; 36 37enum ovl_inode_flag { 38 /* Pure upper dir that may contain non pure upper entries */ 39 OVL_IMPURE, 40 /* Non-merge dir that may contain whiteout entries */ 41 OVL_WHITEOUTS, 42 OVL_INDEX, 43 OVL_UPPERDATA, 44 /* Inode number will remain constant over copy up. */ 45 OVL_CONST_INO, 46}; 47 48enum ovl_entry_flag { 49 OVL_E_UPPER_ALIAS, 50 OVL_E_OPAQUE, 51 OVL_E_CONNECTED, 52}; 53 54enum { 55 OVL_XINO_OFF, 56 OVL_XINO_AUTO, 57 OVL_XINO_ON, 58}; 59 60/* 61 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 62 * where: 63 * origin.fh - exported file handle of the lower file 64 * origin.uuid - uuid of the lower filesystem 65 */ 66#define OVL_FH_VERSION 0 67#define OVL_FH_MAGIC 0xfb 68 69/* CPU byte order required for fid decoding: */ 70#define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 71#define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 72/* Is the real inode encoded in fid an upper inode? */ 73#define OVL_FH_FLAG_PATH_UPPER (1 << 2) 74 75#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ 76 OVL_FH_FLAG_PATH_UPPER) 77 78#if defined(__LITTLE_ENDIAN) 79#define OVL_FH_FLAG_CPU_ENDIAN 0 80#elif defined(__BIG_ENDIAN) 81#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 82#else 83#error Endianness not defined 84#endif 85 86/* The type used to be returned by overlay exportfs for misaligned fid */ 87#define OVL_FILEID_V0 0xfb 88/* The type returned by overlay exportfs for 32bit aligned fid */ 89#define OVL_FILEID_V1 0xf8 90 91/* On-disk format for "origin" file handle */ 92struct ovl_fb { 93 u8 version; /* 0 */ 94 u8 magic; /* 0xfb */ 95 u8 len; /* size of this header + size of fid */ 96 u8 flags; /* OVL_FH_FLAG_* */ 97 u8 type; /* fid_type of fid */ 98 uuid_t uuid; /* uuid of filesystem */ 99 u32 fid[]; /* file identifier should be 32bit aligned in-memory */ 100} __packed; 101 102/* In-memory and on-wire format for overlay file handle */ 103struct ovl_fh { 104 u8 padding[3]; /* make sure fb.fid is 32bit aligned */ 105 union { 106 struct ovl_fb fb; 107 u8 buf[0]; 108 }; 109} __packed; 110 111#define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) 112#define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) 113#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ 114 offsetof(struct ovl_fb, fid)) 115 116extern const char *ovl_xattr_table[]; 117static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) 118{ 119 return ovl_xattr_table[ox]; 120} 121 122static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 123{ 124 int err = vfs_rmdir(dir, dentry); 125 126 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 127 return err; 128} 129 130static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 131{ 132 int err = vfs_unlink(dir, dentry, NULL); 133 134 pr_debug("unlink(%pd2) = %i\n", dentry, err); 135 return err; 136} 137 138static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 139 struct dentry *new_dentry) 140{ 141 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 142 143 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); 144 return err; 145} 146 147static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 148 umode_t mode) 149{ 150 int err = vfs_create(dir, dentry, mode, true); 151 152 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 153 return err; 154} 155 156static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 157 umode_t mode) 158{ 159 int err = vfs_mkdir(dir, dentry, mode); 160 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 161 return err; 162} 163 164static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 165 umode_t mode, dev_t dev) 166{ 167 int err = vfs_mknod(dir, dentry, mode, dev); 168 169 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); 170 return err; 171} 172 173static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 174 const char *oldname) 175{ 176 int err = vfs_symlink(dir, dentry, oldname); 177 178 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 179 return err; 180} 181 182static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry, 183 enum ovl_xattr ox, void *value, 184 size_t size) 185{ 186 const char *name = ovl_xattr(ofs, ox); 187 return vfs_getxattr(dentry, name, value, size); 188} 189 190static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, 191 enum ovl_xattr ox, const void *value, 192 size_t size) 193{ 194 const char *name = ovl_xattr(ofs, ox); 195 int err = vfs_setxattr(dentry, name, value, size, 0); 196 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", 197 dentry, name, min((int)size, 48), value, size, err); 198 return err; 199} 200 201static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, 202 enum ovl_xattr ox) 203{ 204 const char *name = ovl_xattr(ofs, ox); 205 int err = vfs_removexattr(dentry, name); 206 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 207 return err; 208} 209 210static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 211 struct inode *newdir, struct dentry *newdentry, 212 unsigned int flags) 213{ 214 int err; 215 216 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); 217 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 218 if (err) { 219 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 220 olddentry, newdentry, err); 221 } 222 return err; 223} 224 225static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 226{ 227 int err = vfs_whiteout(dir, dentry); 228 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 229 return err; 230} 231 232static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 233{ 234 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 235 int err = PTR_ERR_OR_ZERO(ret); 236 237 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 238 return ret; 239} 240 241static inline bool ovl_open_flags_need_copy_up(int flags) 242{ 243 if (!flags) 244 return false; 245 246 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); 247} 248 249/* util.c */ 250int ovl_want_write(struct dentry *dentry); 251void ovl_drop_write(struct dentry *dentry); 252struct dentry *ovl_workdir(struct dentry *dentry); 253const struct cred *ovl_override_creds(struct super_block *sb); 254int ovl_can_decode_fh(struct super_block *sb); 255struct dentry *ovl_indexdir(struct super_block *sb); 256bool ovl_index_all(struct super_block *sb); 257bool ovl_verify_lower(struct super_block *sb); 258struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 259bool ovl_dentry_remote(struct dentry *dentry); 260void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); 261void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry); 262void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, 263 unsigned int mask); 264bool ovl_dentry_weird(struct dentry *dentry); 265enum ovl_path_type ovl_path_type(struct dentry *dentry); 266void ovl_path_upper(struct dentry *dentry, struct path *path); 267void ovl_path_lower(struct dentry *dentry, struct path *path); 268void ovl_path_lowerdata(struct dentry *dentry, struct path *path); 269enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 270struct dentry *ovl_dentry_upper(struct dentry *dentry); 271struct dentry *ovl_dentry_lower(struct dentry *dentry); 272struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); 273const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); 274struct dentry *ovl_dentry_real(struct dentry *dentry); 275struct dentry *ovl_i_dentry_upper(struct inode *inode); 276struct inode *ovl_inode_upper(struct inode *inode); 277struct inode *ovl_inode_lower(struct inode *inode); 278struct inode *ovl_inode_lowerdata(struct inode *inode); 279struct inode *ovl_inode_real(struct inode *inode); 280struct inode *ovl_inode_realdata(struct inode *inode); 281struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); 282void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); 283void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); 284void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); 285bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); 286bool ovl_dentry_is_opaque(struct dentry *dentry); 287bool ovl_dentry_is_whiteout(struct dentry *dentry); 288void ovl_dentry_set_opaque(struct dentry *dentry); 289bool ovl_dentry_has_upper_alias(struct dentry *dentry); 290void ovl_dentry_set_upper_alias(struct dentry *dentry); 291bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); 292bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); 293bool ovl_has_upperdata(struct inode *inode); 294void ovl_set_upperdata(struct inode *inode); 295bool ovl_redirect_dir(struct super_block *sb); 296const char *ovl_dentry_get_redirect(struct dentry *dentry); 297void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 298void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); 299void ovl_dir_modified(struct dentry *dentry, bool impurity); 300u64 ovl_dentry_version_get(struct dentry *dentry); 301bool ovl_is_whiteout(struct dentry *dentry); 302struct file *ovl_path_open(struct path *path, int flags); 303int ovl_copy_up_start(struct dentry *dentry, int flags); 304void ovl_copy_up_end(struct dentry *dentry); 305bool ovl_already_copied_up(struct dentry *dentry, int flags); 306bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry); 307bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, 308 enum ovl_xattr ox); 309int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 310 enum ovl_xattr ox, const void *value, size_t size, 311 int xerr); 312int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 313bool ovl_inuse_trylock(struct dentry *dentry); 314void ovl_inuse_unlock(struct dentry *dentry); 315bool ovl_is_inuse(struct dentry *dentry); 316bool ovl_need_index(struct dentry *dentry); 317int ovl_nlink_start(struct dentry *dentry); 318void ovl_nlink_end(struct dentry *dentry); 319int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); 320int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry); 321bool ovl_is_metacopy_dentry(struct dentry *dentry); 322char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, 323 int padding); 324int ovl_sync_status(struct ovl_fs *ofs); 325 326static inline void ovl_set_flag(unsigned long flag, struct inode *inode) 327{ 328 set_bit(flag, &OVL_I(inode)->flags); 329} 330 331static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) 332{ 333 clear_bit(flag, &OVL_I(inode)->flags); 334} 335 336static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) 337{ 338 return test_bit(flag, &OVL_I(inode)->flags); 339} 340 341static inline bool ovl_is_impuredir(struct super_block *sb, 342 struct dentry *dentry) 343{ 344 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE); 345} 346 347/* 348 * With xino=auto, we do best effort to keep all inodes on same st_dev and 349 * d_ino consistent with st_ino. 350 * With xino=on, we do the same effort but we warn if we failed. 351 */ 352static inline bool ovl_xino_warn(struct super_block *sb) 353{ 354 return OVL_FS(sb)->config.xino == OVL_XINO_ON; 355} 356 357/* All layers on same fs? */ 358static inline bool ovl_same_fs(struct super_block *sb) 359{ 360 return OVL_FS(sb)->xino_mode == 0; 361} 362 363/* All overlay inodes have same st_dev? */ 364static inline bool ovl_same_dev(struct super_block *sb) 365{ 366 return OVL_FS(sb)->xino_mode >= 0; 367} 368 369static inline unsigned int ovl_xino_bits(struct super_block *sb) 370{ 371 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0; 372} 373 374static inline void ovl_inode_lock(struct inode *inode) 375{ 376 mutex_lock(&OVL_I(inode)->lock); 377} 378 379static inline int ovl_inode_lock_interruptible(struct inode *inode) 380{ 381 return mutex_lock_interruptible(&OVL_I(inode)->lock); 382} 383 384static inline void ovl_inode_unlock(struct inode *inode) 385{ 386 mutex_unlock(&OVL_I(inode)->lock); 387} 388 389 390/* namei.c */ 391int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); 392 393static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) 394{ 395 if (fh_len < sizeof(struct ovl_fh)) 396 return -EINVAL; 397 398 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); 399} 400 401struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, 402 bool connected); 403int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, 404 struct dentry *upperdentry, struct ovl_path **stackp); 405int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, 406 enum ovl_xattr ox, struct dentry *real, bool is_upper, 407 bool set); 408struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); 409int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); 410int ovl_get_index_name(struct dentry *origin, struct qstr *name); 411struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); 412struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, 413 struct dentry *origin, bool verify); 414int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 415struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, 416 unsigned int flags); 417bool ovl_lower_positive(struct dentry *dentry); 418 419static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, 420 struct dentry *origin, bool set) 421{ 422 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, 423 false, set); 424} 425 426static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, 427 struct dentry *upper, bool set) 428{ 429 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); 430} 431 432/* readdir.c */ 433extern const struct file_operations ovl_dir_operations; 434struct file *ovl_dir_real_file(const struct file *file, bool want_upper); 435int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 436void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 437void ovl_cache_free(struct list_head *list); 438void ovl_dir_cache_free(struct inode *inode); 439int ovl_check_d_type_supported(struct path *realpath); 440int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 441 struct dentry *dentry, int level); 442int ovl_indexdir_cleanup(struct ovl_fs *ofs); 443 444/* 445 * Can we iterate real dir directly? 446 * 447 * Non-merge dir may contain whiteouts from a time it was a merge upper, before 448 * lower dir was removed under it and possibly before it was rotated from upper 449 * to lower layer. 450 */ 451static inline bool ovl_dir_is_real(struct dentry *dir) 452{ 453 return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir)); 454} 455 456/* inode.c */ 457int ovl_set_nlink_upper(struct dentry *dentry); 458int ovl_set_nlink_lower(struct dentry *dentry); 459unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 460 struct dentry *upperdentry, 461 unsigned int fallback); 462int ovl_setattr(struct dentry *dentry, struct iattr *attr); 463int ovl_getattr(const struct path *path, struct kstat *stat, 464 u32 request_mask, unsigned int flags); 465int ovl_permission(struct inode *inode, int mask); 466int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 467 const void *value, size_t size, int flags); 468int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 469 void *value, size_t size); 470ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 471struct posix_acl *ovl_get_acl(struct inode *inode, int type); 472int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); 473bool ovl_is_private_xattr(struct super_block *sb, const char *name); 474 475struct ovl_inode_params { 476 struct inode *newinode; 477 struct dentry *upperdentry; 478 struct ovl_path *lowerpath; 479 bool index; 480 unsigned int numlower; 481 char *redirect; 482 struct dentry *lowerdata; 483}; 484void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 485 unsigned long ino, int fsid); 486struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 487struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 488 bool is_upper); 489bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); 490struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); 491struct inode *ovl_get_inode(struct super_block *sb, 492 struct ovl_inode_params *oip); 493static inline void ovl_copyattr(struct inode *from, struct inode *to) 494{ 495 to->i_uid = from->i_uid; 496 to->i_gid = from->i_gid; 497 to->i_mode = from->i_mode; 498 to->i_atime = from->i_atime; 499 to->i_mtime = from->i_mtime; 500 to->i_ctime = from->i_ctime; 501 i_size_write(to, i_size_read(from)); 502} 503 504static inline void ovl_copyflags(struct inode *from, struct inode *to) 505{ 506 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; 507 508 inode_set_flags(to, from->i_flags & mask, mask); 509} 510 511/* dir.c */ 512extern const struct inode_operations ovl_dir_inode_operations; 513int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, 514 struct dentry *dentry); 515struct ovl_cattr { 516 dev_t rdev; 517 umode_t mode; 518 const char *link; 519 struct dentry *hardlink; 520}; 521 522#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) 523 524int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode); 525struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, 526 struct ovl_cattr *attr); 527int ovl_cleanup(struct inode *dir, struct dentry *dentry); 528struct dentry *ovl_lookup_temp(struct dentry *workdir); 529struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); 530 531/* file.c */ 532extern const struct file_operations ovl_file_operations; 533int __init ovl_aio_request_cache_init(void); 534void ovl_aio_request_cache_destroy(void); 535long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 536long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); 537 538/* copy_up.c */ 539int ovl_copy_up(struct dentry *dentry); 540int ovl_copy_up_with_data(struct dentry *dentry); 541int ovl_maybe_copy_up(struct dentry *dentry, int flags); 542int ovl_copy_xattr(struct super_block *sb, struct dentry *old, 543 struct dentry *new); 544int ovl_set_attr(struct dentry *upper, struct kstat *stat); 545struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); 546int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 547 struct dentry *upper); 548 549/* export.c */ 550extern const struct export_operations ovl_export_operations; 551