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. */
58 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
60 * origin.fh - exported file handle of the lower file
61 * origin.uuid - uuid of the lower filesystem
63 #define OVL_FH_VERSION 0
64 #define OVL_FH_MAGIC 0xfb
66 /* CPU byte order required for fid decoding: */
67 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
68 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
69 /* Is the real inode encoded in fid an upper inode? */
70 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
72 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
73 OVL_FH_FLAG_PATH_UPPER)
75 #if defined(__LITTLE_ENDIAN)
76 #define OVL_FH_FLAG_CPU_ENDIAN 0
77 #elif defined(__BIG_ENDIAN)
78 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
80 #error Endianness not defined
83 /* The type used to be returned by overlay exportfs for misaligned fid */
84 #define OVL_FILEID_V0 0xfb
85 /* The type returned by overlay exportfs for 32bit aligned fid */
86 #define OVL_FILEID_V1 0xf8
88 /* On-disk format for "origin" file handle */
92 u8 len; /* size of this header + size of fid */
93 u8 flags; /* OVL_FH_FLAG_* */
94 u8 type; /* fid_type of fid */
95 uuid_t uuid; /* uuid of filesystem */
96 u32 fid[]; /* file identifier should be 32bit aligned in-memory */
99 /* In-memory and on-wire format for overlay file handle */
101 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
108 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
109 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
110 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
111 offsetof(struct ovl_fb, fid))
113 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
115 int err = vfs_rmdir(dir, dentry);
117 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
121 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
123 int err = vfs_unlink(dir, dentry, NULL);
125 pr_debug("unlink(%pd2) = %i\n", dentry, err);
129 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
130 struct dentry *new_dentry)
132 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
134 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
138 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
141 int err = vfs_create(dir, dentry, mode, true);
143 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
147 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
150 int err = vfs_mkdir(dir, dentry, mode);
151 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
155 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
156 umode_t mode, dev_t dev)
158 int err = vfs_mknod(dir, dentry, mode, dev);
160 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
164 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
167 int err = vfs_symlink(dir, dentry, oldname);
169 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
173 static inline ssize_t ovl_do_getxattr(struct dentry *dentry, const char *name,
174 void *value, size_t size)
176 return vfs_getxattr(dentry, name, value, size);
179 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
180 const void *value, size_t size)
182 int err = vfs_setxattr(dentry, name, value, size, 0);
183 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
184 dentry, name, min((int)size, 48), value, size, err);
188 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
190 int err = vfs_removexattr(dentry, name);
191 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
195 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
196 struct inode *newdir, struct dentry *newdentry,
201 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
202 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
204 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
205 olddentry, newdentry, err);
210 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
212 int err = vfs_whiteout(dir, dentry);
213 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
217 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
219 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
220 int err = PTR_ERR_OR_ZERO(ret);
222 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
226 static inline bool ovl_open_flags_need_copy_up(int flags)
231 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
235 int ovl_want_write(struct dentry *dentry);
236 void ovl_drop_write(struct dentry *dentry);
237 struct dentry *ovl_workdir(struct dentry *dentry);
238 const struct cred *ovl_override_creds(struct super_block *sb);
239 int ovl_can_decode_fh(struct super_block *sb);
240 struct dentry *ovl_indexdir(struct super_block *sb);
241 bool ovl_index_all(struct super_block *sb);
242 bool ovl_verify_lower(struct super_block *sb);
243 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
244 bool ovl_dentry_remote(struct dentry *dentry);
245 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
247 bool ovl_dentry_weird(struct dentry *dentry);
248 enum ovl_path_type ovl_path_type(struct dentry *dentry);
249 void ovl_path_upper(struct dentry *dentry, struct path *path);
250 void ovl_path_lower(struct dentry *dentry, struct path *path);
251 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
252 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
253 struct dentry *ovl_dentry_upper(struct dentry *dentry);
254 struct dentry *ovl_dentry_lower(struct dentry *dentry);
255 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
256 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
257 struct dentry *ovl_dentry_real(struct dentry *dentry);
258 struct dentry *ovl_i_dentry_upper(struct inode *inode);
259 struct inode *ovl_inode_upper(struct inode *inode);
260 struct inode *ovl_inode_lower(struct inode *inode);
261 struct inode *ovl_inode_lowerdata(struct inode *inode);
262 struct inode *ovl_inode_real(struct inode *inode);
263 struct inode *ovl_inode_realdata(struct inode *inode);
264 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
265 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
266 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
267 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
268 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
269 bool ovl_dentry_is_opaque(struct dentry *dentry);
270 bool ovl_dentry_is_whiteout(struct dentry *dentry);
271 void ovl_dentry_set_opaque(struct dentry *dentry);
272 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
273 void ovl_dentry_set_upper_alias(struct dentry *dentry);
274 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
275 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
276 bool ovl_has_upperdata(struct inode *inode);
277 void ovl_set_upperdata(struct inode *inode);
278 bool ovl_redirect_dir(struct super_block *sb);
279 const char *ovl_dentry_get_redirect(struct dentry *dentry);
280 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
281 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
282 void ovl_dir_modified(struct dentry *dentry, bool impurity);
283 u64 ovl_dentry_version_get(struct dentry *dentry);
284 bool ovl_is_whiteout(struct dentry *dentry);
285 struct file *ovl_path_open(struct path *path, int flags);
286 int ovl_copy_up_start(struct dentry *dentry, int flags);
287 void ovl_copy_up_end(struct dentry *dentry);
288 bool ovl_already_copied_up(struct dentry *dentry, int flags);
289 bool ovl_check_origin_xattr(struct dentry *dentry);
290 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
291 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
292 const char *name, const void *value, size_t size,
294 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
295 void ovl_set_flag(unsigned long flag, struct inode *inode);
296 void ovl_clear_flag(unsigned long flag, struct inode *inode);
297 bool ovl_test_flag(unsigned long flag, struct inode *inode);
298 bool ovl_inuse_trylock(struct dentry *dentry);
299 void ovl_inuse_unlock(struct dentry *dentry);
300 bool ovl_is_inuse(struct dentry *dentry);
301 bool ovl_need_index(struct dentry *dentry);
302 int ovl_nlink_start(struct dentry *dentry);
303 void ovl_nlink_end(struct dentry *dentry);
304 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
305 int ovl_check_metacopy_xattr(struct dentry *dentry);
306 bool ovl_is_metacopy_dentry(struct dentry *dentry);
307 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
309 static inline bool ovl_is_impuredir(struct dentry *dentry)
311 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
315 * With xino=auto, we do best effort to keep all inodes on same st_dev and
316 * d_ino consistent with st_ino.
317 * With xino=on, we do the same effort but we warn if we failed.
319 static inline bool ovl_xino_warn(struct super_block *sb)
321 return OVL_FS(sb)->config.xino == OVL_XINO_ON;
324 /* All layers on same fs? */
325 static inline bool ovl_same_fs(struct super_block *sb)
327 return OVL_FS(sb)->xino_mode == 0;
330 /* All overlay inodes have same st_dev? */
331 static inline bool ovl_same_dev(struct super_block *sb)
333 return OVL_FS(sb)->xino_mode >= 0;
336 static inline unsigned int ovl_xino_bits(struct super_block *sb)
338 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
341 static inline void ovl_inode_lock(struct inode *inode)
343 mutex_lock(&OVL_I(inode)->lock);
346 static inline int ovl_inode_lock_interruptible(struct inode *inode)
348 return mutex_lock_interruptible(&OVL_I(inode)->lock);
351 static inline void ovl_inode_unlock(struct inode *inode)
353 mutex_unlock(&OVL_I(inode)->lock);
358 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
360 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
362 if (fh_len < sizeof(struct ovl_fh))
365 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
368 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
370 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
371 struct dentry *upperdentry, struct ovl_path **stackp);
372 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
373 struct dentry *real, bool is_upper, bool set);
374 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
375 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
376 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
377 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
378 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
379 struct dentry *origin, bool verify);
380 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
381 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
383 bool ovl_lower_positive(struct dentry *dentry);
385 static inline int ovl_verify_origin(struct dentry *upper,
386 struct dentry *origin, bool set)
388 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
391 static inline int ovl_verify_upper(struct dentry *index,
392 struct dentry *upper, bool set)
394 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
398 extern const struct file_operations ovl_dir_operations;
399 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
400 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
401 void ovl_cache_free(struct list_head *list);
402 void ovl_dir_cache_free(struct inode *inode);
403 int ovl_check_d_type_supported(struct path *realpath);
404 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
405 struct dentry *dentry, int level);
406 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
409 int ovl_set_nlink_upper(struct dentry *dentry);
410 int ovl_set_nlink_lower(struct dentry *dentry);
411 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
412 struct dentry *upperdentry,
413 unsigned int fallback);
414 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
415 int ovl_getattr(const struct path *path, struct kstat *stat,
416 u32 request_mask, unsigned int flags);
417 int ovl_permission(struct inode *inode, int mask);
418 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
419 const void *value, size_t size, int flags);
420 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
421 void *value, size_t size);
422 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
423 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
424 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
425 bool ovl_is_private_xattr(const char *name);
427 struct ovl_inode_params {
428 struct inode *newinode;
429 struct dentry *upperdentry;
430 struct ovl_path *lowerpath;
432 unsigned int numlower;
434 struct dentry *lowerdata;
436 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
437 unsigned long ino, int fsid);
438 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
439 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
441 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
442 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
443 struct inode *ovl_get_inode(struct super_block *sb,
444 struct ovl_inode_params *oip);
445 static inline void ovl_copyattr(struct inode *from, struct inode *to)
447 to->i_uid = from->i_uid;
448 to->i_gid = from->i_gid;
449 to->i_mode = from->i_mode;
450 to->i_atime = from->i_atime;
451 to->i_mtime = from->i_mtime;
452 to->i_ctime = from->i_ctime;
453 i_size_write(to, i_size_read(from));
456 static inline void ovl_copyflags(struct inode *from, struct inode *to)
458 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
460 inode_set_flags(to, from->i_flags & mask, mask);
464 extern const struct inode_operations ovl_dir_inode_operations;
465 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
466 struct dentry *dentry);
471 struct dentry *hardlink;
474 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
476 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
477 struct ovl_cattr *attr);
478 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
479 struct dentry *ovl_lookup_temp(struct dentry *workdir);
480 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
483 extern const struct file_operations ovl_file_operations;
484 int __init ovl_aio_request_cache_init(void);
485 void ovl_aio_request_cache_destroy(void);
488 int ovl_copy_up(struct dentry *dentry);
489 int ovl_copy_up_with_data(struct dentry *dentry);
490 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
491 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
492 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
493 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
494 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
495 struct dentry *upper);
498 extern const struct export_operations ovl_export_operations;