1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 *
4 * Copyright (C) 2011 Novell Inc.
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/uuid.h>
9 #include <linux/fs.h>
10 #include <linux/fsverity.h>
11 #include <linux/namei.h>
12 #include <linux/posix_acl.h>
13 #include <linux/posix_acl_xattr.h>
14 #include "ovl_entry.h"
15
16 #undef pr_fmt
17 #define pr_fmt(fmt) "overlayfs: " fmt
18
19 enum ovl_path_type {
20 __OVL_PATH_UPPER = (1 << 0),
21 __OVL_PATH_MERGE = (1 << 1),
22 __OVL_PATH_ORIGIN = (1 << 2),
23 };
24
25 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
26 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
27 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
28
29 #define OVL_XATTR_NAMESPACE "overlay."
30 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
31 #define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1)
32 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
33 #define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1)
34
35 #define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE
36 #define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1)
37 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX
38 #define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1)
39 #define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX
40 #define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1)
41
42 enum ovl_xattr {
43 OVL_XATTR_OPAQUE,
44 OVL_XATTR_REDIRECT,
45 OVL_XATTR_ORIGIN,
46 OVL_XATTR_IMPURE,
47 OVL_XATTR_NLINK,
48 OVL_XATTR_UPPER,
49 OVL_XATTR_UUID,
50 OVL_XATTR_METACOPY,
51 OVL_XATTR_PROTATTR,
52 OVL_XATTR_XWHITEOUT,
53 };
54
55 enum ovl_inode_flag {
56 /* Pure upper dir that may contain non pure upper entries */
57 OVL_IMPURE,
58 /* Non-merge dir that may contain whiteout entries */
59 OVL_WHITEOUTS,
60 OVL_INDEX,
61 OVL_UPPERDATA,
62 /* Inode number will remain constant over copy up. */
63 OVL_CONST_INO,
64 OVL_HAS_DIGEST,
65 OVL_VERIFIED_DIGEST,
66 };
67
68 enum ovl_entry_flag {
69 OVL_E_UPPER_ALIAS,
70 OVL_E_OPAQUE,
71 OVL_E_CONNECTED,
72 /* Lower stack may contain xwhiteout entries */
73 OVL_E_XWHITEOUTS,
74 };
75
76 enum {
77 OVL_REDIRECT_OFF, /* "off" mode is never used. In effect */
78 OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */
79 OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */
80 OVL_REDIRECT_ON,
81 };
82
83 enum {
84 OVL_UUID_OFF,
85 OVL_UUID_NULL,
86 OVL_UUID_AUTO,
87 OVL_UUID_ON,
88 };
89
90 enum {
91 OVL_XINO_OFF,
92 OVL_XINO_AUTO,
93 OVL_XINO_ON,
94 };
95
96 enum {
97 OVL_VERITY_OFF,
98 OVL_VERITY_ON,
99 OVL_VERITY_REQUIRE,
100 };
101
102 /*
103 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
104 * where:
105 * origin.fh - exported file handle of the lower file
106 * origin.uuid - uuid of the lower filesystem
107 */
108 #define OVL_FH_VERSION 0
109 #define OVL_FH_MAGIC 0xfb
110
111 /* CPU byte order required for fid decoding: */
112 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
113 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
114 /* Is the real inode encoded in fid an upper inode? */
115 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
116
117 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
118 OVL_FH_FLAG_PATH_UPPER)
119
120 #if defined(__LITTLE_ENDIAN)
121 #define OVL_FH_FLAG_CPU_ENDIAN 0
122 #elif defined(__BIG_ENDIAN)
123 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
124 #else
125 #error Endianness not defined
126 #endif
127
128 /* The type used to be returned by overlay exportfs for misaligned fid */
129 #define OVL_FILEID_V0 0xfb
130 /* The type returned by overlay exportfs for 32bit aligned fid */
131 #define OVL_FILEID_V1 0xf8
132
133 /* On-disk format for "origin" file handle */
134 struct ovl_fb {
135 u8 version; /* 0 */
136 u8 magic; /* 0xfb */
137 u8 len; /* size of this header + size of fid */
138 u8 flags; /* OVL_FH_FLAG_* */
139 u8 type; /* fid_type of fid */
140 uuid_t uuid; /* uuid of filesystem */
141 u32 fid[]; /* file identifier should be 32bit aligned in-memory */
142 } __packed;
143
144 /* In-memory and on-wire format for overlay file handle */
145 struct ovl_fh {
146 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
147 union {
148 struct ovl_fb fb;
149 DECLARE_FLEX_ARRAY(u8, buf);
150 };
151 } __packed;
152
153 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
154 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
155 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
156 offsetof(struct ovl_fb, fid))
157
158 /* On-disk format for "metacopy" xattr (if non-zero size) */
159 struct ovl_metacopy {
160 u8 version; /* 0 */
161 u8 len; /* size of this header + used digest bytes */
162 u8 flags;
163 u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */
164 u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; /* Only the used part on disk */
165 } __packed;
166
167 #define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy))
168 #define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE)
169 #define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE }
170
171 static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy)
172 {
173 if (metacopy->len < OVL_METACOPY_MIN_SIZE)
174 return 0;
175 return (int)metacopy->len - OVL_METACOPY_MIN_SIZE;
176 }
177
178 /* No atime modification on underlying */
179 #define OVL_OPEN_FLAGS (O_NOATIME)
180
181 extern const char *const ovl_xattr_table[][2];
182 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
183 {
184 return ovl_xattr_table[ox][ofs->config.userxattr];
185 }
186
187 /*
188 * When changing ownership of an upper object map the intended ownership
189 * according to the upper layer's idmapping. When an upper mount idmaps files
190 * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
191 * this object will report it as being owned by id 1000 when calling stat via
192 * the upper mount.
193 * In order to change ownership of an object so stat reports id 1000 when
194 * called on an idmapped upper mount the value written to disk - i.e., the
195 * value stored in ia_*id - must 1001. The mount mapping helper will thus take
196 * care to map 1000 to 1001.
197 * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
198 */
199 static inline int ovl_do_notify_change(struct ovl_fs *ofs,
200 struct dentry *upperdentry,
201 struct iattr *attr)
202 {
203 return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
204 }
205
206 static inline int ovl_do_rmdir(struct ovl_fs *ofs,
207 struct inode *dir, struct dentry *dentry)
208 {
209 int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry);
210
211 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
212 return err;
213 }
214
215 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
216 struct dentry *dentry)
217 {
218 int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
219
220 pr_debug("unlink(%pd2) = %i\n", dentry, err);
221 return err;
222 }
223
224 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
225 struct inode *dir, struct dentry *new_dentry)
226 {
227 int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir,
228 new_dentry, NULL);
229
230 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
231 return err;
232 }
233
234 static inline int ovl_do_create(struct ovl_fs *ofs,
235 struct inode *dir, struct dentry *dentry,
236 umode_t mode)
237 {
238 int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true);
239
240 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
241 return err;
242 }
243
244 static inline int ovl_do_mkdir(struct ovl_fs *ofs,
245 struct inode *dir, struct dentry *dentry,
246 umode_t mode)
247 {
248 int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
249 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
250 return err;
251 }
252
253 static inline int ovl_do_mknod(struct ovl_fs *ofs,
254 struct inode *dir, struct dentry *dentry,
255 umode_t mode, dev_t dev)
256 {
257 int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev);
258
259 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
260 return err;
261 }
262
263 static inline int ovl_do_symlink(struct ovl_fs *ofs,
264 struct inode *dir, struct dentry *dentry,
265 const char *oldname)
266 {
267 int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname);
268
269 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
270 return err;
271 }
272
273 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
274 void *value, size_t size)
275 {
276 int err, len;
277
278 WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
279
280 err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry,
281 name, value, size);
282 len = (value && err > 0) ? err : 0;
283
284 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
285 path->dentry, name, min(len, 48), value, size, err);
286 return err;
287 }
288
289 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
290 struct dentry *upperdentry,
291 enum ovl_xattr ox, void *value,
292 size_t size)
293 {
294 struct path upperpath = {
295 .dentry = upperdentry,
296 .mnt = ovl_upper_mnt(ofs),
297 };
298
299 return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
300 }
301
302 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
303 const struct path *path,
304 enum ovl_xattr ox, void *value,
305 size_t size)
306 {
307 return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
308 }
309
310 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
311 const char *name, const void *value,
312 size_t size, int flags)
313 {
314 int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
315 value, size, flags);
316
317 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
318 dentry, name, min((int)size, 48), value, size, flags, err);
319 return err;
320 }
321
322 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
323 enum ovl_xattr ox, const void *value,
324 size_t size)
325 {
326 return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
327 }
328
329 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
330 const char *name)
331 {
332 int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
333 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
334 return err;
335 }
336
337 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
338 enum ovl_xattr ox)
339 {
340 return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
341 }
342
343 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
344 const char *acl_name, struct posix_acl *acl)
345 {
346 return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl);
347 }
348
349 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
350 const char *acl_name)
351 {
352 return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name);
353 }
354
355 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
356 struct dentry *olddentry, struct inode *newdir,
357 struct dentry *newdentry, unsigned int flags)
358 {
359 int err;
360 struct renamedata rd = {
361 .old_mnt_idmap = ovl_upper_mnt_idmap(ofs),
362 .old_dir = olddir,
363 .old_dentry = olddentry,
364 .new_mnt_idmap = ovl_upper_mnt_idmap(ofs),
365 .new_dir = newdir,
366 .new_dentry = newdentry,
367 .flags = flags,
368 };
369
370 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
371 err = vfs_rename(&rd);
372 if (err) {
373 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
374 olddentry, newdentry, err);
375 }
376 return err;
377 }
378
379 static inline int ovl_do_whiteout(struct ovl_fs *ofs,
380 struct inode *dir, struct dentry *dentry)
381 {
382 int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry);
383 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
384 return err;
385 }
386
387 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
388 struct dentry *dentry, umode_t mode)
389 {
390 struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
391 struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path,
392 mode, O_LARGEFILE | O_WRONLY,
393 current_cred());
394 int err = PTR_ERR_OR_ZERO(file);
395
396 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
397 return file;
398 }
399
400 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
401 const char *name,
402 struct dentry *base, int len)
403 {
404 return lookup_one(ovl_upper_mnt_idmap(ofs), name, base, len);
405 }
406
407 static inline bool ovl_open_flags_need_copy_up(int flags)
408 {
409 if (!flags)
410 return false;
411
412 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
413 }
414
415 static inline int ovl_do_getattr(const struct path *path, struct kstat *stat,
416 u32 request_mask, unsigned int flags)
417 {
418 if (flags & AT_GETATTR_NOSEC)
419 return vfs_getattr_nosec(path, stat, request_mask, flags);
420 return vfs_getattr(path, stat, request_mask, flags);
421 }
422
423 /* util.c */
424 int ovl_get_write_access(struct dentry *dentry);
425 void ovl_put_write_access(struct dentry *dentry);
426 void ovl_start_write(struct dentry *dentry);
427 void ovl_end_write(struct dentry *dentry);
428 int ovl_want_write(struct dentry *dentry);
429 void ovl_drop_write(struct dentry *dentry);
430 struct dentry *ovl_workdir(struct dentry *dentry);
431 const struct cred *ovl_override_creds(struct super_block *sb);
432
433 static inline const struct cred *ovl_creds(struct super_block *sb)
434 {
435 return OVL_FS(sb)->creator_cred;
436 }
437
438 int ovl_can_decode_fh(struct super_block *sb);
439 struct dentry *ovl_indexdir(struct super_block *sb);
440 bool ovl_index_all(struct super_block *sb);
441 bool ovl_verify_lower(struct super_block *sb);
442 struct ovl_path *ovl_stack_alloc(unsigned int n);
443 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
444 void ovl_stack_put(struct ovl_path *stack, unsigned int n);
445 void ovl_stack_free(struct ovl_path *stack, unsigned int n);
446 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
447 void ovl_free_entry(struct ovl_entry *oe);
448 bool ovl_dentry_remote(struct dentry *dentry);
449 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
450 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
451 struct ovl_entry *oe);
452 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
453 struct ovl_entry *oe, unsigned int mask);
454 bool ovl_dentry_weird(struct dentry *dentry);
455 enum ovl_path_type ovl_path_type(struct dentry *dentry);
456 void ovl_path_upper(struct dentry *dentry, struct path *path);
457 void ovl_path_lower(struct dentry *dentry, struct path *path);
458 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
459 struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
460 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
461 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
462 struct dentry *ovl_dentry_upper(struct dentry *dentry);
463 struct dentry *ovl_dentry_lower(struct dentry *dentry);
464 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
465 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
466 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
467 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
468 struct dentry *ovl_dentry_real(struct dentry *dentry);
469 struct dentry *ovl_i_dentry_upper(struct inode *inode);
470 struct inode *ovl_inode_upper(struct inode *inode);
471 struct inode *ovl_inode_lower(struct inode *inode);
472 struct inode *ovl_inode_lowerdata(struct inode *inode);
473 struct inode *ovl_inode_real(struct inode *inode);
474 struct inode *ovl_inode_realdata(struct inode *inode);
475 const char *ovl_lowerdata_redirect(struct inode *inode);
476 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
477 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
478 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
479 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
480 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
481 bool ovl_dentry_is_opaque(struct dentry *dentry);
482 bool ovl_dentry_is_whiteout(struct dentry *dentry);
483 void ovl_dentry_set_opaque(struct dentry *dentry);
484 bool ovl_dentry_has_xwhiteouts(struct dentry *dentry);
485 void ovl_dentry_set_xwhiteouts(struct dentry *dentry);
486 void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
487 const struct ovl_layer *layer);
488 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
489 void ovl_dentry_set_upper_alias(struct dentry *dentry);
490 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
491 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
492 bool ovl_has_upperdata(struct inode *inode);
493 void ovl_set_upperdata(struct inode *inode);
494 const char *ovl_dentry_get_redirect(struct dentry *dentry);
495 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
496 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
497 void ovl_dir_modified(struct dentry *dentry, bool impurity);
498 u64 ovl_inode_version_get(struct inode *inode);
499 bool ovl_is_whiteout(struct dentry *dentry);
500 bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
501 struct file *ovl_path_open(const struct path *path, int flags);
502 int ovl_copy_up_start(struct dentry *dentry, int flags);
503 void ovl_copy_up_end(struct dentry *dentry);
504 bool ovl_already_copied_up(struct dentry *dentry, int flags);
505 char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
506 enum ovl_xattr ox);
507 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
508 bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
509 bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
510 const struct path *upperpath);
511
512 static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
513 struct dentry *upperdentry)
514 {
515 struct path upperpath = {
516 .dentry = upperdentry,
517 .mnt = ovl_upper_mnt(ofs),
518 };
519 return ovl_path_is_whiteout(ofs, &upperpath);
520 }
521
522 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
523 struct dentry *upperdentry)
524 {
525 struct path upperpath = {
526 .dentry = upperdentry,
527 .mnt = ovl_upper_mnt(ofs),
528 };
529 return ovl_path_check_origin_xattr(ofs, &upperpath);
530 }
531
532 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
533 enum ovl_xattr ox, const void *value, size_t size,
534 int xerr);
535 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
536 bool ovl_inuse_trylock(struct dentry *dentry);
537 void ovl_inuse_unlock(struct dentry *dentry);
538 bool ovl_is_inuse(struct dentry *dentry);
539 bool ovl_need_index(struct dentry *dentry);
540 int ovl_nlink_start(struct dentry *dentry);
541 void ovl_nlink_end(struct dentry *dentry);
542 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
543 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path,
544 struct ovl_metacopy *data);
545 int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d,
546 struct ovl_metacopy *metacopy);
547 bool ovl_is_metacopy_dentry(struct dentry *dentry);
548 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
549 int ovl_ensure_verity_loaded(struct path *path);
550 int ovl_get_verity_xattr(struct ovl_fs *ofs, const struct path *path,
551 u8 *digest_buf, int *buf_length);
552 int ovl_validate_verity(struct ovl_fs *ofs,
553 struct path *metapath,
554 struct path *datapath);
555 int ovl_get_verity_digest(struct ovl_fs *ofs, struct path *src,
556 struct ovl_metacopy *metacopy);
557 int ovl_sync_status(struct ovl_fs *ofs);
558
559 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
560 {
561 set_bit(flag, &OVL_I(inode)->flags);
562 }
563
564 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
565 {
566 clear_bit(flag, &OVL_I(inode)->flags);
567 }
568
569 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
570 {
571 return test_bit(flag, &OVL_I(inode)->flags);
572 }
573
574 static inline bool ovl_is_impuredir(struct super_block *sb,
575 struct dentry *upperdentry)
576 {
577 struct ovl_fs *ofs = OVL_FS(sb);
578 struct path upperpath = {
579 .dentry = upperdentry,
580 .mnt = ovl_upper_mnt(ofs),
581 };
582
583 return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y';
584 }
585
586 static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs,
587 const struct path *path)
588 {
589 return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE);
590 }
591
592 static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
593 {
594 return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
595 }
596
597 static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
598 {
599 return ofs->config.redirect_mode == OVL_REDIRECT_ON;
600 }
601
602 static inline bool ovl_origin_uuid(struct ovl_fs *ofs)
603 {
604 return ofs->config.uuid != OVL_UUID_OFF;
605 }
606
607 static inline bool ovl_has_fsid(struct ovl_fs *ofs)
608 {
609 return ofs->config.uuid == OVL_UUID_ON ||
610 ofs->config.uuid == OVL_UUID_AUTO;
611 }
612
613 /*
614 * With xino=auto, we do best effort to keep all inodes on same st_dev and
615 * d_ino consistent with st_ino.
616 * With xino=on, we do the same effort but we warn if we failed.
617 */
618 static inline bool ovl_xino_warn(struct ovl_fs *ofs)
619 {
620 return ofs->config.xino == OVL_XINO_ON;
621 }
622
623 /*
624 * To avoid regressions in existing setups with overlay lower offline changes,
625 * we allow lower changes only if none of the new features are used.
626 */
627 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
628 {
629 return (!ofs->config.index && !ofs->config.metacopy &&
630 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
631 }
632
633 /* All layers on same fs? */
634 static inline bool ovl_same_fs(struct ovl_fs *ofs)
635 {
636 return ofs->xino_mode == 0;
637 }
638
639 /* All overlay inodes have same st_dev? */
640 static inline bool ovl_same_dev(struct ovl_fs *ofs)
641 {
642 return ofs->xino_mode >= 0;
643 }
644
645 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
646 {
647 return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
648 }
649
650 static inline void ovl_inode_lock(struct inode *inode)
651 {
652 mutex_lock(&OVL_I(inode)->lock);
653 }
654
655 static inline int ovl_inode_lock_interruptible(struct inode *inode)
656 {
657 return mutex_lock_interruptible(&OVL_I(inode)->lock);
658 }
659
660 static inline void ovl_inode_unlock(struct inode *inode)
661 {
662 mutex_unlock(&OVL_I(inode)->lock);
663 }
664
665
666 /* namei.c */
667 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
668
669 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
670 {
671 if (fh_len < sizeof(struct ovl_fh))
672 return -EINVAL;
673
674 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
675 }
676
677 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
678 struct vfsmount *mnt, bool connected);
679 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
680 struct dentry *upperdentry, struct ovl_path **stackp);
681 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
682 enum ovl_xattr ox, const struct ovl_fh *fh,
683 bool is_upper, bool set);
684 int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
685 enum ovl_xattr ox, struct dentry *real,
686 bool is_upper, bool set);
687 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
688 bool connected);
689 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
690 int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
691 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
692 struct qstr *name);
693 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
694 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
695 struct dentry *origin, bool verify);
696 int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
697 const struct ovl_layer **layer);
698 int ovl_verify_lowerdata(struct dentry *dentry);
699 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
700 unsigned int flags);
701 bool ovl_lower_positive(struct dentry *dentry);
702
703 static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper,
704 const struct ovl_fh *fh, bool set)
705 {
706 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set);
707 }
708
709 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
710 struct dentry *origin, bool set)
711 {
712 return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin,
713 false, set);
714 }
715
716 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
717 struct dentry *upper, bool set)
718 {
719 return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper,
720 true, set);
721 }
722
723 /* readdir.c */
724 extern const struct file_operations ovl_dir_operations;
725 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
726 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
727 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
728 struct list_head *list);
729 void ovl_cache_free(struct list_head *list);
730 void ovl_dir_cache_free(struct inode *inode);
731 int ovl_check_d_type_supported(const struct path *realpath);
732 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
733 struct vfsmount *mnt, struct dentry *dentry, int level);
734 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
735
736 /*
737 * Can we iterate real dir directly?
738 *
739 * Non-merge dir may contain whiteouts from a time it was a merge upper, before
740 * lower dir was removed under it and possibly before it was rotated from upper
741 * to lower layer.
742 */
743 static inline bool ovl_dir_is_real(struct inode *dir)
744 {
745 return !ovl_test_flag(OVL_WHITEOUTS, dir);
746 }
747
748 /* inode.c */
749 int ovl_set_nlink_upper(struct dentry *dentry);
750 int ovl_set_nlink_lower(struct dentry *dentry);
751 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
752 struct dentry *upperdentry,
753 unsigned int fallback);
754 int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
755 int mask);
756
757 #ifdef CONFIG_FS_POSIX_ACL
758 struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
759 struct inode *inode, int type,
760 bool rcu, bool noperm);
761 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
762 bool rcu)
763 {
764 return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true);
765 }
766 static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
767 struct dentry *dentry, int type)
768 {
769 return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false);
770 }
771 int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
772 struct posix_acl *acl, int type);
773 struct posix_acl *ovl_get_acl_path(const struct path *path,
774 const char *acl_name, bool noperm);
775 #else
776 #define ovl_get_inode_acl NULL
777 #define ovl_get_acl NULL
778 #define ovl_set_acl NULL
779 static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
780 const char *acl_name,
781 bool noperm)
782 {
783 return NULL;
784 }
785 #endif
786
787 int ovl_update_time(struct inode *inode, int flags);
788 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
789
790 struct ovl_inode_params {
791 struct inode *newinode;
792 struct dentry *upperdentry;
793 struct ovl_entry *oe;
794 bool index;
795 char *redirect;
796 char *lowerdata_redirect;
797 };
798 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
799 unsigned long ino, int fsid);
800 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
801 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
802 bool is_upper);
803 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
804 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
805 struct inode *ovl_get_inode(struct super_block *sb,
806 struct ovl_inode_params *oip);
807 void ovl_copyattr(struct inode *to);
808
809 /* vfs inode flags copied from real to ovl inode */
810 #define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
811 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
812 #define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE)
813
814 /*
815 * fileattr flags copied from lower to upper inode on copy up.
816 * We cannot copy up immutable/append-only flags, because that would prevent
817 * linking temp inode to upper dir, so we store them in xattr instead.
818 */
819 #define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL)
820 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
821 #define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL)
822 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
823
824 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
825 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
826 struct fileattr *fa);
827
828 static inline void ovl_copyflags(struct inode *from, struct inode *to)
829 {
830 unsigned int mask = OVL_COPY_I_FLAGS_MASK;
831
832 inode_set_flags(to, from->i_flags & mask, mask);
833 }
834
835 /* dir.c */
836 extern const struct inode_operations ovl_dir_inode_operations;
837 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
838 struct dentry *dentry);
839 struct ovl_cattr {
840 dev_t rdev;
841 umode_t mode;
842 const char *link;
843 struct dentry *hardlink;
844 };
845
846 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
847
848 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
849 struct dentry **newdentry, umode_t mode);
850 struct dentry *ovl_create_real(struct ovl_fs *ofs,
851 struct inode *dir, struct dentry *newdentry,
852 struct ovl_cattr *attr);
853 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
854 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
855 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
856 struct ovl_cattr *attr);
857
858 /* file.c */
859 extern const struct file_operations ovl_file_operations;
860 int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa);
861 int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa);
862 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
863 int ovl_fileattr_set(struct mnt_idmap *idmap,
864 struct dentry *dentry, struct fileattr *fa);
865
866 /* copy_up.c */
867 int ovl_copy_up(struct dentry *dentry);
868 int ovl_copy_up_with_data(struct dentry *dentry);
869 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
870 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
871 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
872 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
873 bool is_upper);
874 struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
875 int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
876 struct dentry *upper);
877
878 /* export.c */
879 extern const struct export_operations ovl_export_operations;
880 extern const struct export_operations ovl_export_fid_operations;
881
882 /* super.c */
883 int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
884
885 /* Will this overlay be forced to mount/remount ro? */
886 static inline bool ovl_force_readonly(struct ovl_fs *ofs)
887 {
888 return (!ovl_upper_mnt(ofs) || !ofs->workdir);
889 }
890
891 /* xattr.c */
892
893 const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
894 int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
895 struct iattr *attr);
896 int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
897 struct kstat *stat, u32 request_mask, unsigned int flags);
898 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
899
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