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_PREFIX XATTR_TRUSTED_PREFIX "overlay."
38 /* Pure upper dir that may contain non pure upper entries */
40 /* Non-merge dir that may contain whiteout entries */
44 /* Inode number will remain constant over copy up. */
61 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
63 * origin.fh - exported file handle of the lower file
64 * origin.uuid - uuid of the lower filesystem
66 #define OVL_FH_VERSION 0
67 #define OVL_FH_MAGIC 0xfb
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)
75 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
76 OVL_FH_FLAG_PATH_UPPER)
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
83 #error Endianness not defined
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
91 /* On-disk format for "origin" file handle */
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 */
102 /* In-memory and on-wire format for overlay file handle */
104 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
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))
116 extern const char *ovl_xattr_table[];
117 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
119 return ovl_xattr_table[ox];
122 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
124 int err = vfs_rmdir(dir, dentry);
126 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
130 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
132 int err = vfs_unlink(dir, dentry, NULL);
134 pr_debug("unlink(%pd2) = %i\n", dentry, err);
138 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
139 struct dentry *new_dentry)
141 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
143 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
147 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
150 int err = vfs_create(dir, dentry, mode, true);
152 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
156 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
159 int err = vfs_mkdir(dir, dentry, mode);
160 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
164 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
165 umode_t mode, dev_t dev)
167 int err = vfs_mknod(dir, dentry, mode, dev);
169 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
173 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
176 int err = vfs_symlink(dir, dentry, oldname);
178 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
182 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
183 enum ovl_xattr ox, void *value,
186 const char *name = ovl_xattr(ofs, ox);
187 return vfs_getxattr(dentry, name, value, size);
190 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
191 enum ovl_xattr ox, const void *value,
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);
201 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
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);
210 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
211 struct inode *newdir, struct dentry *newdentry,
216 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
217 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
219 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
220 olddentry, newdentry, err);
225 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
227 int err = vfs_whiteout(dir, dentry);
228 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
232 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
234 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
235 int err = PTR_ERR_OR_ZERO(ret);
237 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
241 static inline bool ovl_open_flags_need_copy_up(int flags)
246 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
250 int ovl_want_write(struct dentry *dentry);
251 void ovl_drop_write(struct dentry *dentry);
252 struct dentry *ovl_workdir(struct dentry *dentry);
253 const struct cred *ovl_override_creds(struct super_block *sb);
254 int ovl_can_decode_fh(struct super_block *sb);
255 struct dentry *ovl_indexdir(struct super_block *sb);
256 bool ovl_index_all(struct super_block *sb);
257 bool ovl_verify_lower(struct super_block *sb);
258 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
259 bool ovl_dentry_remote(struct dentry *dentry);
260 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
261 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry);
262 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
264 bool ovl_dentry_weird(struct dentry *dentry);
265 enum ovl_path_type ovl_path_type(struct dentry *dentry);
266 void ovl_path_upper(struct dentry *dentry, struct path *path);
267 void ovl_path_lower(struct dentry *dentry, struct path *path);
268 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
269 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
270 struct dentry *ovl_dentry_upper(struct dentry *dentry);
271 struct dentry *ovl_dentry_lower(struct dentry *dentry);
272 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
273 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
274 struct dentry *ovl_dentry_real(struct dentry *dentry);
275 struct dentry *ovl_i_dentry_upper(struct inode *inode);
276 struct inode *ovl_inode_upper(struct inode *inode);
277 struct inode *ovl_inode_lower(struct inode *inode);
278 struct inode *ovl_inode_lowerdata(struct inode *inode);
279 struct inode *ovl_inode_real(struct inode *inode);
280 struct inode *ovl_inode_realdata(struct inode *inode);
281 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
282 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
283 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
284 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
285 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
286 bool ovl_dentry_is_opaque(struct dentry *dentry);
287 bool ovl_dentry_is_whiteout(struct dentry *dentry);
288 void ovl_dentry_set_opaque(struct dentry *dentry);
289 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
290 void ovl_dentry_set_upper_alias(struct dentry *dentry);
291 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
292 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
293 bool ovl_has_upperdata(struct inode *inode);
294 void ovl_set_upperdata(struct inode *inode);
295 bool ovl_redirect_dir(struct super_block *sb);
296 const char *ovl_dentry_get_redirect(struct dentry *dentry);
297 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
298 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
299 void ovl_dir_modified(struct dentry *dentry, bool impurity);
300 u64 ovl_dentry_version_get(struct dentry *dentry);
301 bool ovl_is_whiteout(struct dentry *dentry);
302 struct file *ovl_path_open(struct path *path, int flags);
303 int ovl_copy_up_start(struct dentry *dentry, int flags);
304 void ovl_copy_up_end(struct dentry *dentry);
305 bool ovl_already_copied_up(struct dentry *dentry, int flags);
306 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
307 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
309 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
310 enum ovl_xattr ox, const void *value, size_t size,
312 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
313 bool ovl_inuse_trylock(struct dentry *dentry);
314 void ovl_inuse_unlock(struct dentry *dentry);
315 bool ovl_is_inuse(struct dentry *dentry);
316 bool ovl_need_index(struct dentry *dentry);
317 int ovl_nlink_start(struct dentry *dentry);
318 void ovl_nlink_end(struct dentry *dentry);
319 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
320 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry);
321 bool ovl_is_metacopy_dentry(struct dentry *dentry);
322 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
324 int ovl_sync_status(struct ovl_fs *ofs);
326 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
328 set_bit(flag, &OVL_I(inode)->flags);
331 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
333 clear_bit(flag, &OVL_I(inode)->flags);
336 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
338 return test_bit(flag, &OVL_I(inode)->flags);
341 static inline bool ovl_is_impuredir(struct super_block *sb,
342 struct dentry *dentry)
344 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE);
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.
352 static inline bool ovl_xino_warn(struct super_block *sb)
354 return OVL_FS(sb)->config.xino == OVL_XINO_ON;
357 /* All layers on same fs? */
358 static inline bool ovl_same_fs(struct super_block *sb)
360 return OVL_FS(sb)->xino_mode == 0;
363 /* All overlay inodes have same st_dev? */
364 static inline bool ovl_same_dev(struct super_block *sb)
366 return OVL_FS(sb)->xino_mode >= 0;
369 static inline unsigned int ovl_xino_bits(struct super_block *sb)
371 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
374 static inline void ovl_inode_lock(struct inode *inode)
376 mutex_lock(&OVL_I(inode)->lock);
379 static inline int ovl_inode_lock_interruptible(struct inode *inode)
381 return mutex_lock_interruptible(&OVL_I(inode)->lock);
384 static inline void ovl_inode_unlock(struct inode *inode)
386 mutex_unlock(&OVL_I(inode)->lock);
391 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
393 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
395 if (fh_len < sizeof(struct ovl_fh))
398 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
401 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
403 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
404 struct dentry *upperdentry, struct ovl_path **stackp);
405 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
406 enum ovl_xattr ox, struct dentry *real, bool is_upper,
408 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
409 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
410 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
411 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
412 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
413 struct dentry *origin, bool verify);
414 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
415 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
417 bool ovl_lower_positive(struct dentry *dentry);
419 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
420 struct dentry *origin, bool set)
422 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
426 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
427 struct dentry *upper, bool set)
429 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
433 extern const struct file_operations ovl_dir_operations;
434 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
435 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
436 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
437 void ovl_cache_free(struct list_head *list);
438 void ovl_dir_cache_free(struct inode *inode);
439 int ovl_check_d_type_supported(struct path *realpath);
440 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
441 struct dentry *dentry, int level);
442 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
445 * Can we iterate real dir directly?
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
451 static inline bool ovl_dir_is_real(struct dentry *dir)
453 return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
457 int ovl_set_nlink_upper(struct dentry *dentry);
458 int ovl_set_nlink_lower(struct dentry *dentry);
459 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
460 struct dentry *upperdentry,
461 unsigned int fallback);
462 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
463 int ovl_getattr(const struct path *path, struct kstat *stat,
464 u32 request_mask, unsigned int flags);
465 int ovl_permission(struct inode *inode, int mask);
466 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
467 const void *value, size_t size, int flags);
468 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
469 void *value, size_t size);
470 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
471 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
472 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
473 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
475 struct ovl_inode_params {
476 struct inode *newinode;
477 struct dentry *upperdentry;
478 struct ovl_path *lowerpath;
480 unsigned int numlower;
482 struct dentry *lowerdata;
484 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
485 unsigned long ino, int fsid);
486 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
487 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
489 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
490 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
491 struct inode *ovl_get_inode(struct super_block *sb,
492 struct ovl_inode_params *oip);
493 static inline void ovl_copyattr(struct inode *from, struct inode *to)
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));
504 static inline void ovl_copyflags(struct inode *from, struct inode *to)
506 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
508 inode_set_flags(to, from->i_flags & mask, mask);
512 extern const struct inode_operations ovl_dir_inode_operations;
513 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
514 struct dentry *dentry);
519 struct dentry *hardlink;
522 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
524 int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode);
525 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
526 struct ovl_cattr *attr);
527 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
528 struct dentry *ovl_lookup_temp(struct dentry *workdir);
529 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
532 extern const struct file_operations ovl_file_operations;
533 int __init ovl_aio_request_cache_init(void);
534 void ovl_aio_request_cache_destroy(void);
535 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
536 long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
539 int ovl_copy_up(struct dentry *dentry);
540 int ovl_copy_up_with_data(struct dentry *dentry);
541 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
542 int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
544 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
545 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
546 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
547 struct dentry *upper);
550 extern const struct export_operations ovl_export_operations;