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
40 /* Pure upper dir that may contain non pure upper entries */
42 /* Non-merge dir that may contain whiteout entries */
46 /* Inode number will remain constant over copy up. */
63 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
65 * origin.fh - exported file handle of the lower file
66 * origin.uuid - uuid of the lower filesystem
68 #define OVL_FH_VERSION 0
69 #define OVL_FH_MAGIC 0xfb
71 /* CPU byte order required for fid decoding: */
72 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
73 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
74 /* Is the real inode encoded in fid an upper inode? */
75 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
77 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
78 OVL_FH_FLAG_PATH_UPPER)
80 #if defined(__LITTLE_ENDIAN)
81 #define OVL_FH_FLAG_CPU_ENDIAN 0
82 #elif defined(__BIG_ENDIAN)
83 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
85 #error Endianness not defined
88 /* The type used to be returned by overlay exportfs for misaligned fid */
89 #define OVL_FILEID_V0 0xfb
90 /* The type returned by overlay exportfs for 32bit aligned fid */
91 #define OVL_FILEID_V1 0xf8
93 /* On-disk format for "origin" file handle */
97 u8 len; /* size of this header + size of fid */
98 u8 flags; /* OVL_FH_FLAG_* */
99 u8 type; /* fid_type of fid */
100 uuid_t uuid; /* uuid of filesystem */
101 u32 fid[]; /* file identifier should be 32bit aligned in-memory */
104 /* In-memory and on-wire format for overlay file handle */
106 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
113 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
114 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
115 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
116 offsetof(struct ovl_fb, fid))
118 extern const char *const ovl_xattr_table[][2];
119 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
121 return ovl_xattr_table[ox][ofs->config.userxattr];
124 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
126 int err = vfs_rmdir(&init_user_ns, dir, dentry);
128 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
132 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
134 int err = vfs_unlink(&init_user_ns, dir, dentry, NULL);
136 pr_debug("unlink(%pd2) = %i\n", dentry, err);
140 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
141 struct dentry *new_dentry)
143 int err = vfs_link(old_dentry, &init_user_ns, dir, new_dentry, NULL);
145 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
149 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
152 int err = vfs_create(&init_user_ns, dir, dentry, mode, true);
154 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
158 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
161 int err = vfs_mkdir(&init_user_ns, dir, dentry, mode);
162 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
166 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
167 umode_t mode, dev_t dev)
169 int err = vfs_mknod(&init_user_ns, dir, dentry, mode, dev);
171 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
175 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
178 int err = vfs_symlink(&init_user_ns, dir, dentry, oldname);
180 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
184 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
185 enum ovl_xattr ox, void *value,
188 const char *name = ovl_xattr(ofs, ox);
189 return vfs_getxattr(&init_user_ns, dentry, name, value, size);
192 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
193 enum ovl_xattr ox, const void *value,
196 const char *name = ovl_xattr(ofs, ox);
197 int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, 0);
198 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
199 dentry, name, min((int)size, 48), value, size, err);
203 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
206 const char *name = ovl_xattr(ofs, ox);
207 int err = vfs_removexattr(&init_user_ns, dentry, name);
208 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
212 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
213 struct inode *newdir, struct dentry *newdentry,
217 struct renamedata rd = {
218 .old_mnt_userns = &init_user_ns,
220 .old_dentry = olddentry,
221 .new_mnt_userns = &init_user_ns,
223 .new_dentry = newdentry,
227 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
228 err = vfs_rename(&rd);
230 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
231 olddentry, newdentry, err);
236 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
238 int err = vfs_whiteout(&init_user_ns, dir, dentry);
239 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
243 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
245 struct dentry *ret = vfs_tmpfile(&init_user_ns, dentry, mode, 0);
246 int err = PTR_ERR_OR_ZERO(ret);
248 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
252 static inline bool ovl_open_flags_need_copy_up(int flags)
257 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
261 int ovl_want_write(struct dentry *dentry);
262 void ovl_drop_write(struct dentry *dentry);
263 struct dentry *ovl_workdir(struct dentry *dentry);
264 const struct cred *ovl_override_creds(struct super_block *sb);
265 int ovl_can_decode_fh(struct super_block *sb);
266 struct dentry *ovl_indexdir(struct super_block *sb);
267 bool ovl_index_all(struct super_block *sb);
268 bool ovl_verify_lower(struct super_block *sb);
269 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
270 bool ovl_dentry_remote(struct dentry *dentry);
271 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
273 bool ovl_dentry_weird(struct dentry *dentry);
274 enum ovl_path_type ovl_path_type(struct dentry *dentry);
275 void ovl_path_upper(struct dentry *dentry, struct path *path);
276 void ovl_path_lower(struct dentry *dentry, struct path *path);
277 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
278 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
279 struct dentry *ovl_dentry_upper(struct dentry *dentry);
280 struct dentry *ovl_dentry_lower(struct dentry *dentry);
281 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
282 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
283 struct dentry *ovl_dentry_real(struct dentry *dentry);
284 struct dentry *ovl_i_dentry_upper(struct inode *inode);
285 struct inode *ovl_inode_upper(struct inode *inode);
286 struct inode *ovl_inode_lower(struct inode *inode);
287 struct inode *ovl_inode_lowerdata(struct inode *inode);
288 struct inode *ovl_inode_real(struct inode *inode);
289 struct inode *ovl_inode_realdata(struct inode *inode);
290 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
291 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
292 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
293 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
294 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
295 bool ovl_dentry_is_opaque(struct dentry *dentry);
296 bool ovl_dentry_is_whiteout(struct dentry *dentry);
297 void ovl_dentry_set_opaque(struct dentry *dentry);
298 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
299 void ovl_dentry_set_upper_alias(struct dentry *dentry);
300 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
301 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
302 bool ovl_has_upperdata(struct inode *inode);
303 void ovl_set_upperdata(struct inode *inode);
304 bool ovl_redirect_dir(struct super_block *sb);
305 const char *ovl_dentry_get_redirect(struct dentry *dentry);
306 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
307 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
308 void ovl_dir_modified(struct dentry *dentry, bool impurity);
309 u64 ovl_dentry_version_get(struct dentry *dentry);
310 bool ovl_is_whiteout(struct dentry *dentry);
311 struct file *ovl_path_open(struct path *path, int flags);
312 int ovl_copy_up_start(struct dentry *dentry, int flags);
313 void ovl_copy_up_end(struct dentry *dentry);
314 bool ovl_already_copied_up(struct dentry *dentry, int flags);
315 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
316 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
318 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
319 enum ovl_xattr ox, const void *value, size_t size,
321 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
322 void ovl_set_flag(unsigned long flag, struct inode *inode);
323 void ovl_clear_flag(unsigned long flag, struct inode *inode);
324 bool ovl_test_flag(unsigned long flag, struct inode *inode);
325 bool ovl_inuse_trylock(struct dentry *dentry);
326 void ovl_inuse_unlock(struct dentry *dentry);
327 bool ovl_is_inuse(struct dentry *dentry);
328 bool ovl_need_index(struct dentry *dentry);
329 int ovl_nlink_start(struct dentry *dentry);
330 void ovl_nlink_end(struct dentry *dentry);
331 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
332 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry);
333 bool ovl_is_metacopy_dentry(struct dentry *dentry);
334 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
336 int ovl_sync_status(struct ovl_fs *ofs);
338 static inline bool ovl_is_impuredir(struct super_block *sb,
339 struct dentry *dentry)
341 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE);
345 * With xino=auto, we do best effort to keep all inodes on same st_dev and
346 * d_ino consistent with st_ino.
347 * With xino=on, we do the same effort but we warn if we failed.
349 static inline bool ovl_xino_warn(struct super_block *sb)
351 return OVL_FS(sb)->config.xino == OVL_XINO_ON;
354 /* All layers on same fs? */
355 static inline bool ovl_same_fs(struct super_block *sb)
357 return OVL_FS(sb)->xino_mode == 0;
360 /* All overlay inodes have same st_dev? */
361 static inline bool ovl_same_dev(struct super_block *sb)
363 return OVL_FS(sb)->xino_mode >= 0;
366 static inline unsigned int ovl_xino_bits(struct super_block *sb)
368 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
371 static inline void ovl_inode_lock(struct inode *inode)
373 mutex_lock(&OVL_I(inode)->lock);
376 static inline int ovl_inode_lock_interruptible(struct inode *inode)
378 return mutex_lock_interruptible(&OVL_I(inode)->lock);
381 static inline void ovl_inode_unlock(struct inode *inode)
383 mutex_unlock(&OVL_I(inode)->lock);
388 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
390 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
392 if (fh_len < sizeof(struct ovl_fh))
395 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
398 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
399 struct vfsmount *mnt, bool connected);
400 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
401 struct dentry *upperdentry, struct ovl_path **stackp);
402 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
403 enum ovl_xattr ox, struct dentry *real, bool is_upper,
405 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
406 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
407 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
409 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
410 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
411 struct dentry *origin, bool verify);
412 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
413 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
415 bool ovl_lower_positive(struct dentry *dentry);
417 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
418 struct dentry *origin, bool set)
420 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
424 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
425 struct dentry *upper, bool set)
427 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
431 extern const struct file_operations ovl_dir_operations;
432 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
433 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
434 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
435 void ovl_cache_free(struct list_head *list);
436 void ovl_dir_cache_free(struct inode *inode);
437 int ovl_check_d_type_supported(struct path *realpath);
438 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
439 struct dentry *dentry, int level);
440 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
443 int ovl_set_nlink_upper(struct dentry *dentry);
444 int ovl_set_nlink_lower(struct dentry *dentry);
445 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
446 struct dentry *upperdentry,
447 unsigned int fallback);
448 int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
450 int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
451 struct kstat *stat, u32 request_mask, unsigned int flags);
452 int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode,
454 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
455 const void *value, size_t size, int flags);
456 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
457 void *value, size_t size);
458 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
459 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
460 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
461 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
463 struct ovl_inode_params {
464 struct inode *newinode;
465 struct dentry *upperdentry;
466 struct ovl_path *lowerpath;
468 unsigned int numlower;
470 struct dentry *lowerdata;
472 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
473 unsigned long ino, int fsid);
474 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
475 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
477 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
478 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
479 struct inode *ovl_get_inode(struct super_block *sb,
480 struct ovl_inode_params *oip);
481 static inline void ovl_copyattr(struct inode *from, struct inode *to)
483 to->i_uid = from->i_uid;
484 to->i_gid = from->i_gid;
485 to->i_mode = from->i_mode;
486 to->i_atime = from->i_atime;
487 to->i_mtime = from->i_mtime;
488 to->i_ctime = from->i_ctime;
489 i_size_write(to, i_size_read(from));
492 static inline void ovl_copyflags(struct inode *from, struct inode *to)
494 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
496 inode_set_flags(to, from->i_flags & mask, mask);
500 extern const struct inode_operations ovl_dir_inode_operations;
501 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
502 struct dentry *dentry);
507 struct dentry *hardlink;
510 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
512 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
513 struct ovl_cattr *attr);
514 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
515 struct dentry *ovl_lookup_temp(struct dentry *workdir);
516 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
519 extern const struct file_operations ovl_file_operations;
520 int __init ovl_aio_request_cache_init(void);
521 void ovl_aio_request_cache_destroy(void);
522 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
523 long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
526 int ovl_copy_up(struct dentry *dentry);
527 int ovl_copy_up_with_data(struct dentry *dentry);
528 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
529 int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
531 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
532 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
534 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry,
535 struct dentry *lower, struct dentry *upper);
538 extern const struct export_operations ovl_export_operations;