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."
26 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
27 #define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
28 #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
29 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
30 #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
31 #define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
32 #define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
35 /* Pure upper dir that may contain non pure upper entries */
37 /* Non-merge dir that may contain whiteout entries */
41 /* Inode number will remain constant over copy up. */
52 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
54 * origin.fh - exported file handle of the lower file
55 * origin.uuid - uuid of the lower filesystem
57 #define OVL_FH_VERSION 0
58 #define OVL_FH_MAGIC 0xfb
60 /* CPU byte order required for fid decoding: */
61 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
62 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
63 /* Is the real inode encoded in fid an upper inode? */
64 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
66 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
67 OVL_FH_FLAG_PATH_UPPER)
69 #if defined(__LITTLE_ENDIAN)
70 #define OVL_FH_FLAG_CPU_ENDIAN 0
71 #elif defined(__BIG_ENDIAN)
72 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
74 #error Endianness not defined
77 /* The type used to be returned by overlay exportfs for misaligned fid */
78 #define OVL_FILEID_V0 0xfb
79 /* The type returned by overlay exportfs for 32bit aligned fid */
80 #define OVL_FILEID_V1 0xf8
82 /* On-disk format for "origin" file handle */
86 u8 len; /* size of this header + size of fid */
87 u8 flags; /* OVL_FH_FLAG_* */
88 u8 type; /* fid_type of fid */
89 uuid_t uuid; /* uuid of filesystem */
90 u32 fid[0]; /* file identifier should be 32bit aligned in-memory */
93 /* In-memory and on-wire format for overlay file handle */
95 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
102 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
103 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
104 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
105 offsetof(struct ovl_fb, fid))
107 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
109 int err = vfs_rmdir(dir, dentry);
111 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
115 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
117 int err = vfs_unlink(dir, dentry, NULL);
119 pr_debug("unlink(%pd2) = %i\n", dentry, err);
123 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
124 struct dentry *new_dentry)
126 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
128 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
132 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
135 int err = vfs_create(dir, dentry, mode, true);
137 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
141 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
144 int err = vfs_mkdir(dir, dentry, mode);
145 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
149 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
150 umode_t mode, dev_t dev)
152 int err = vfs_mknod(dir, dentry, mode, dev);
154 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
158 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
161 int err = vfs_symlink(dir, dentry, oldname);
163 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
167 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
168 const void *value, size_t size, int flags)
170 int err = vfs_setxattr(dentry, name, value, size, flags);
171 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
172 dentry, name, min((int)size, 48), value, size, flags, err);
176 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
178 int err = vfs_removexattr(dentry, name);
179 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
183 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
184 struct inode *newdir, struct dentry *newdentry,
189 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
190 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
192 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
193 olddentry, newdentry, err);
198 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
200 int err = vfs_whiteout(dir, dentry);
201 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
205 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
207 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
208 int err = PTR_ERR_OR_ZERO(ret);
210 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
214 static inline bool ovl_open_flags_need_copy_up(int flags)
219 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
223 int ovl_want_write(struct dentry *dentry);
224 void ovl_drop_write(struct dentry *dentry);
225 struct dentry *ovl_workdir(struct dentry *dentry);
226 const struct cred *ovl_override_creds(struct super_block *sb);
227 int ovl_can_decode_fh(struct super_block *sb);
228 struct dentry *ovl_indexdir(struct super_block *sb);
229 bool ovl_index_all(struct super_block *sb);
230 bool ovl_verify_lower(struct super_block *sb);
231 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
232 bool ovl_dentry_remote(struct dentry *dentry);
233 bool ovl_dentry_weird(struct dentry *dentry);
234 enum ovl_path_type ovl_path_type(struct dentry *dentry);
235 void ovl_path_upper(struct dentry *dentry, struct path *path);
236 void ovl_path_lower(struct dentry *dentry, struct path *path);
237 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
238 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
239 struct dentry *ovl_dentry_upper(struct dentry *dentry);
240 struct dentry *ovl_dentry_lower(struct dentry *dentry);
241 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
242 struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
243 struct dentry *ovl_dentry_real(struct dentry *dentry);
244 struct dentry *ovl_i_dentry_upper(struct inode *inode);
245 struct inode *ovl_inode_upper(struct inode *inode);
246 struct inode *ovl_inode_lower(struct inode *inode);
247 struct inode *ovl_inode_lowerdata(struct inode *inode);
248 struct inode *ovl_inode_real(struct inode *inode);
249 struct inode *ovl_inode_realdata(struct inode *inode);
250 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
251 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
252 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
253 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
254 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
255 bool ovl_dentry_is_opaque(struct dentry *dentry);
256 bool ovl_dentry_is_whiteout(struct dentry *dentry);
257 void ovl_dentry_set_opaque(struct dentry *dentry);
258 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
259 void ovl_dentry_set_upper_alias(struct dentry *dentry);
260 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
261 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
262 bool ovl_has_upperdata(struct inode *inode);
263 void ovl_set_upperdata(struct inode *inode);
264 bool ovl_redirect_dir(struct super_block *sb);
265 const char *ovl_dentry_get_redirect(struct dentry *dentry);
266 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
267 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
268 struct dentry *lowerdentry, struct dentry *lowerdata);
269 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
270 void ovl_dir_modified(struct dentry *dentry, bool impurity);
271 u64 ovl_dentry_version_get(struct dentry *dentry);
272 bool ovl_is_whiteout(struct dentry *dentry);
273 struct file *ovl_path_open(struct path *path, int flags);
274 int ovl_copy_up_start(struct dentry *dentry, int flags);
275 void ovl_copy_up_end(struct dentry *dentry);
276 bool ovl_already_copied_up(struct dentry *dentry, int flags);
277 bool ovl_check_origin_xattr(struct dentry *dentry);
278 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
279 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
280 const char *name, const void *value, size_t size,
282 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
283 void ovl_set_flag(unsigned long flag, struct inode *inode);
284 void ovl_clear_flag(unsigned long flag, struct inode *inode);
285 bool ovl_test_flag(unsigned long flag, struct inode *inode);
286 bool ovl_inuse_trylock(struct dentry *dentry);
287 void ovl_inuse_unlock(struct dentry *dentry);
288 bool ovl_is_inuse(struct dentry *dentry);
289 bool ovl_need_index(struct dentry *dentry);
290 int ovl_nlink_start(struct dentry *dentry);
291 void ovl_nlink_end(struct dentry *dentry);
292 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
293 int ovl_check_metacopy_xattr(struct dentry *dentry);
294 bool ovl_is_metacopy_dentry(struct dentry *dentry);
295 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
296 ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
299 static inline bool ovl_is_impuredir(struct dentry *dentry)
301 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
304 /* All layers on same fs? */
305 static inline bool ovl_same_fs(struct super_block *sb)
307 return OVL_FS(sb)->xino_mode == 0;
310 /* All overlay inodes have same st_dev? */
311 static inline bool ovl_same_dev(struct super_block *sb)
313 return OVL_FS(sb)->xino_mode >= 0;
316 static inline unsigned int ovl_xino_bits(struct super_block *sb)
318 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
321 static inline int ovl_inode_lock(struct inode *inode)
323 return mutex_lock_interruptible(&OVL_I(inode)->lock);
326 static inline void ovl_inode_unlock(struct inode *inode)
328 mutex_unlock(&OVL_I(inode)->lock);
333 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
335 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
337 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
340 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
342 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
343 struct dentry *upperdentry, struct ovl_path **stackp);
344 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
345 struct dentry *real, bool is_upper, bool set);
346 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
347 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
348 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
349 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
350 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
351 struct dentry *origin, bool verify);
352 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
353 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
355 bool ovl_lower_positive(struct dentry *dentry);
357 static inline int ovl_verify_origin(struct dentry *upper,
358 struct dentry *origin, bool set)
360 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
363 static inline int ovl_verify_upper(struct dentry *index,
364 struct dentry *upper, bool set)
366 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
370 extern const struct file_operations ovl_dir_operations;
371 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
372 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
373 void ovl_cache_free(struct list_head *list);
374 void ovl_dir_cache_free(struct inode *inode);
375 int ovl_check_d_type_supported(struct path *realpath);
376 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
377 struct dentry *dentry, int level);
378 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
381 int ovl_set_nlink_upper(struct dentry *dentry);
382 int ovl_set_nlink_lower(struct dentry *dentry);
383 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
384 struct dentry *upperdentry,
385 unsigned int fallback);
386 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
387 int ovl_getattr(const struct path *path, struct kstat *stat,
388 u32 request_mask, unsigned int flags);
389 int ovl_permission(struct inode *inode, int mask);
390 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
391 const void *value, size_t size, int flags);
392 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
393 void *value, size_t size);
394 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
395 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
396 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
397 bool ovl_is_private_xattr(const char *name);
399 struct ovl_inode_params {
400 struct inode *newinode;
401 struct dentry *upperdentry;
402 struct ovl_path *lowerpath;
403 struct dentry *index;
404 unsigned int numlower;
406 struct dentry *lowerdata;
408 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
409 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
411 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
412 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
413 struct inode *ovl_get_inode(struct super_block *sb,
414 struct ovl_inode_params *oip);
415 static inline void ovl_copyattr(struct inode *from, struct inode *to)
417 to->i_uid = from->i_uid;
418 to->i_gid = from->i_gid;
419 to->i_mode = from->i_mode;
420 to->i_atime = from->i_atime;
421 to->i_mtime = from->i_mtime;
422 to->i_ctime = from->i_ctime;
423 i_size_write(to, i_size_read(from));
426 static inline void ovl_copyflags(struct inode *from, struct inode *to)
428 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
430 inode_set_flags(to, from->i_flags & mask, mask);
434 extern const struct inode_operations ovl_dir_inode_operations;
435 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
436 struct dentry *dentry);
441 struct dentry *hardlink;
444 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
446 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
447 struct ovl_cattr *attr);
448 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
449 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
452 extern const struct file_operations ovl_file_operations;
455 int ovl_copy_up(struct dentry *dentry);
456 int ovl_copy_up_with_data(struct dentry *dentry);
457 int ovl_copy_up_flags(struct dentry *dentry, int flags);
458 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
459 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
460 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
461 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
462 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
463 struct dentry *upper);
466 extern const struct export_operations ovl_export_operations;