1 /* SPDX-License-Identifier: GPL-2.0-only */
4 * Copyright (C) 2011 Novell Inc.
7 #include <linux/kernel.h>
8 #include <linux/uuid.h>
10 #include "ovl_entry.h"
13 #define pr_fmt(fmt) "overlayfs: " fmt
16 __OVL_PATH_UPPER = (1 << 0),
17 __OVL_PATH_MERGE = (1 << 1),
18 __OVL_PATH_ORIGIN = (1 << 2),
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)
25 #define OVL_XATTR_NAMESPACE "overlay."
26 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
27 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
41 /* Pure upper dir that may contain non pure upper entries */
43 /* Non-merge dir that may contain whiteout entries */
47 /* Inode number will remain constant over copy up. */
64 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
66 * origin.fh - exported file handle of the lower file
67 * origin.uuid - uuid of the lower filesystem
69 #define OVL_FH_VERSION 0
70 #define OVL_FH_MAGIC 0xfb
72 /* CPU byte order required for fid decoding: */
73 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
74 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
75 /* Is the real inode encoded in fid an upper inode? */
76 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
78 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
79 OVL_FH_FLAG_PATH_UPPER)
81 #if defined(__LITTLE_ENDIAN)
82 #define OVL_FH_FLAG_CPU_ENDIAN 0
83 #elif defined(__BIG_ENDIAN)
84 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
86 #error Endianness not defined
89 /* The type used to be returned by overlay exportfs for misaligned fid */
90 #define OVL_FILEID_V0 0xfb
91 /* The type returned by overlay exportfs for 32bit aligned fid */
92 #define OVL_FILEID_V1 0xf8
94 /* On-disk format for "origin" file handle */
98 u8 len; /* size of this header + size of fid */
99 u8 flags; /* OVL_FH_FLAG_* */
100 u8 type; /* fid_type of fid */
101 uuid_t uuid; /* uuid of filesystem */
102 u32 fid[]; /* file identifier should be 32bit aligned in-memory */
105 /* In-memory and on-wire format for overlay file handle */
107 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
110 DECLARE_FLEX_ARRAY(u8, buf);
114 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
115 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
116 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
117 offsetof(struct ovl_fb, fid))
119 extern const char *const ovl_xattr_table[][2];
120 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
122 return ovl_xattr_table[ox][ofs->config.userxattr];
125 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
127 int err = vfs_rmdir(&init_user_ns, dir, dentry);
129 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
133 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
135 int err = vfs_unlink(&init_user_ns, dir, dentry, NULL);
137 pr_debug("unlink(%pd2) = %i\n", dentry, err);
141 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
142 struct dentry *new_dentry)
144 int err = vfs_link(old_dentry, &init_user_ns, dir, new_dentry, NULL);
146 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
150 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
153 int err = vfs_create(&init_user_ns, dir, dentry, mode, true);
155 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
159 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
162 int err = vfs_mkdir(&init_user_ns, dir, dentry, mode);
163 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
167 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
168 umode_t mode, dev_t dev)
170 int err = vfs_mknod(&init_user_ns, dir, dentry, mode, dev);
172 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
176 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
179 int err = vfs_symlink(&init_user_ns, dir, dentry, oldname);
181 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
185 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
186 enum ovl_xattr ox, void *value,
189 const char *name = ovl_xattr(ofs, ox);
190 int err = vfs_getxattr(&init_user_ns, dentry, name, value, size);
191 int len = (value && err > 0) ? err : 0;
193 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
194 dentry, name, min(len, 48), value, size, err);
198 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
199 enum ovl_xattr ox, const void *value,
202 const char *name = ovl_xattr(ofs, ox);
203 int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, 0);
204 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
205 dentry, name, min((int)size, 48), value, size, err);
209 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
212 const char *name = ovl_xattr(ofs, ox);
213 int err = vfs_removexattr(&init_user_ns, dentry, name);
214 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
218 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
219 struct inode *newdir, struct dentry *newdentry,
223 struct renamedata rd = {
224 .old_mnt_userns = &init_user_ns,
226 .old_dentry = olddentry,
227 .new_mnt_userns = &init_user_ns,
229 .new_dentry = newdentry,
233 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
234 err = vfs_rename(&rd);
236 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
237 olddentry, newdentry, err);
242 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
244 int err = vfs_whiteout(&init_user_ns, dir, dentry);
245 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
249 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
251 struct dentry *ret = vfs_tmpfile(&init_user_ns, dentry, mode, 0);
252 int err = PTR_ERR_OR_ZERO(ret);
254 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
258 static inline bool ovl_open_flags_need_copy_up(int flags)
263 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
266 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
269 * To avoid regressions in existing setups with overlay lower offline
270 * changes, we allow lower changes only if none of the new features
273 return (!ofs->config.index && !ofs->config.metacopy &&
274 !ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
279 int ovl_want_write(struct dentry *dentry);
280 void ovl_drop_write(struct dentry *dentry);
281 struct dentry *ovl_workdir(struct dentry *dentry);
282 const struct cred *ovl_override_creds(struct super_block *sb);
283 int ovl_can_decode_fh(struct super_block *sb);
284 struct dentry *ovl_indexdir(struct super_block *sb);
285 bool ovl_index_all(struct super_block *sb);
286 bool ovl_verify_lower(struct super_block *sb);
287 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
288 bool ovl_dentry_remote(struct dentry *dentry);
289 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
290 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry);
291 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
293 bool ovl_dentry_weird(struct dentry *dentry);
294 enum ovl_path_type ovl_path_type(struct dentry *dentry);
295 void ovl_path_upper(struct dentry *dentry, struct path *path);
296 void ovl_path_lower(struct dentry *dentry, struct path *path);
297 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
298 void ovl_i_path_real(struct inode *inode, struct path *path);
299 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
300 struct dentry *ovl_dentry_upper(struct dentry *dentry);
301 struct dentry *ovl_dentry_lower(struct dentry *dentry);
302 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
303 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
304 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
305 struct dentry *ovl_dentry_real(struct dentry *dentry);
306 struct dentry *ovl_i_dentry_upper(struct inode *inode);
307 struct inode *ovl_inode_upper(struct inode *inode);
308 struct inode *ovl_inode_lower(struct inode *inode);
309 struct inode *ovl_inode_lowerdata(struct inode *inode);
310 struct inode *ovl_inode_real(struct inode *inode);
311 struct inode *ovl_inode_realdata(struct inode *inode);
312 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
313 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
314 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
315 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
316 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
317 bool ovl_dentry_is_opaque(struct dentry *dentry);
318 bool ovl_dentry_is_whiteout(struct dentry *dentry);
319 void ovl_dentry_set_opaque(struct dentry *dentry);
320 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
321 void ovl_dentry_set_upper_alias(struct dentry *dentry);
322 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
323 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
324 bool ovl_has_upperdata(struct inode *inode);
325 void ovl_set_upperdata(struct inode *inode);
326 bool ovl_redirect_dir(struct super_block *sb);
327 const char *ovl_dentry_get_redirect(struct dentry *dentry);
328 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
329 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
330 void ovl_dir_modified(struct dentry *dentry, bool impurity);
331 u64 ovl_dentry_version_get(struct dentry *dentry);
332 bool ovl_is_whiteout(struct dentry *dentry);
333 struct file *ovl_path_open(struct path *path, int flags);
334 int ovl_copy_up_start(struct dentry *dentry, int flags);
335 void ovl_copy_up_end(struct dentry *dentry);
336 bool ovl_already_copied_up(struct dentry *dentry, int flags);
337 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
338 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
340 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
341 enum ovl_xattr ox, const void *value, size_t size,
343 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
344 bool ovl_inuse_trylock(struct dentry *dentry);
345 void ovl_inuse_unlock(struct dentry *dentry);
346 bool ovl_is_inuse(struct dentry *dentry);
347 bool ovl_need_index(struct dentry *dentry);
348 int ovl_nlink_start(struct dentry *dentry);
349 void ovl_nlink_end(struct dentry *dentry);
350 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
351 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry);
352 bool ovl_is_metacopy_dentry(struct dentry *dentry);
353 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
355 int ovl_sync_status(struct ovl_fs *ofs);
357 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
359 set_bit(flag, &OVL_I(inode)->flags);
362 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
364 clear_bit(flag, &OVL_I(inode)->flags);
367 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
369 return test_bit(flag, &OVL_I(inode)->flags);
372 static inline bool ovl_is_impuredir(struct super_block *sb,
373 struct dentry *dentry)
375 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE);
379 * With xino=auto, we do best effort to keep all inodes on same st_dev and
380 * d_ino consistent with st_ino.
381 * With xino=on, we do the same effort but we warn if we failed.
383 static inline bool ovl_xino_warn(struct super_block *sb)
385 return OVL_FS(sb)->config.xino == OVL_XINO_ON;
388 /* All layers on same fs? */
389 static inline bool ovl_same_fs(struct super_block *sb)
391 return OVL_FS(sb)->xino_mode == 0;
394 /* All overlay inodes have same st_dev? */
395 static inline bool ovl_same_dev(struct super_block *sb)
397 return OVL_FS(sb)->xino_mode >= 0;
400 static inline unsigned int ovl_xino_bits(struct super_block *sb)
402 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
405 static inline void ovl_inode_lock(struct inode *inode)
407 mutex_lock(&OVL_I(inode)->lock);
410 static inline int ovl_inode_lock_interruptible(struct inode *inode)
412 return mutex_lock_interruptible(&OVL_I(inode)->lock);
415 static inline void ovl_inode_unlock(struct inode *inode)
417 mutex_unlock(&OVL_I(inode)->lock);
422 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
424 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
426 if (fh_len < sizeof(struct ovl_fh))
429 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
432 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
433 struct vfsmount *mnt, bool connected);
434 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
435 struct dentry *upperdentry, struct ovl_path **stackp);
436 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
437 enum ovl_xattr ox, struct dentry *real, bool is_upper,
439 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
440 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
441 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
443 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
444 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
445 struct dentry *origin, bool verify);
446 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
447 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
449 bool ovl_lower_positive(struct dentry *dentry);
451 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
452 struct dentry *origin, bool set)
454 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
458 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
459 struct dentry *upper, bool set)
461 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
465 extern const struct file_operations ovl_dir_operations;
466 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
467 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
468 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
469 void ovl_cache_free(struct list_head *list);
470 void ovl_dir_cache_free(struct inode *inode);
471 int ovl_check_d_type_supported(struct path *realpath);
472 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
473 struct dentry *dentry, int level);
474 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
477 * Can we iterate real dir directly?
479 * Non-merge dir may contain whiteouts from a time it was a merge upper, before
480 * lower dir was removed under it and possibly before it was rotated from upper
483 static inline bool ovl_dir_is_real(struct dentry *dir)
485 return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
489 int ovl_set_nlink_upper(struct dentry *dentry);
490 int ovl_set_nlink_lower(struct dentry *dentry);
491 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
492 struct dentry *upperdentry,
493 unsigned int fallback);
494 int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
496 int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
497 struct kstat *stat, u32 request_mask, unsigned int flags);
498 int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode,
500 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
501 const void *value, size_t size, int flags);
502 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
503 void *value, size_t size);
504 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
505 struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu);
506 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
507 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
509 struct ovl_inode_params {
510 struct inode *newinode;
511 struct dentry *upperdentry;
512 struct ovl_path *lowerpath;
514 unsigned int numlower;
516 struct dentry *lowerdata;
518 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
519 unsigned long ino, int fsid);
520 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
521 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
523 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
524 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
525 struct inode *ovl_get_inode(struct super_block *sb,
526 struct ovl_inode_params *oip);
527 void ovl_copyattr(struct inode *to);
529 /* vfs inode flags copied from real to ovl inode */
530 #define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
531 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
532 #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE)
535 * fileattr flags copied from lower to upper inode on copy up.
536 * We cannot copy up immutable/append-only flags, because that would prevent
537 * linking temp inode to upper dir, so we store them in xattr instead.
539 #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL)
540 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
541 #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL)
542 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
544 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
545 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
546 struct fileattr *fa);
548 static inline void ovl_copyflags(struct inode *from, struct inode *to)
550 unsigned int mask = OVL_COPY_I_FLAGS_MASK;
552 inode_set_flags(to, from->i_flags & mask, mask);
556 extern const struct inode_operations ovl_dir_inode_operations;
557 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
558 struct dentry *dentry);
563 struct dentry *hardlink;
566 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
568 int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode);
569 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
570 struct ovl_cattr *attr);
571 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
572 struct dentry *ovl_lookup_temp(struct dentry *workdir);
573 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
576 extern const struct file_operations ovl_file_operations;
577 int __init ovl_aio_request_cache_init(void);
578 void ovl_aio_request_cache_destroy(void);
579 int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa);
580 int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa);
581 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
582 int ovl_fileattr_set(struct user_namespace *mnt_userns,
583 struct dentry *dentry, struct fileattr *fa);
586 int ovl_copy_up(struct dentry *dentry);
587 int ovl_copy_up_with_data(struct dentry *dentry);
588 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
589 int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
591 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
592 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
594 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
595 struct dentry *upper);
598 extern const struct export_operations ovl_export_operations;