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
19enum 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
42enum 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
55enum 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
68enum 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
76enum {
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
83enum {
84 OVL_UUID_OFF,
85 OVL_UUID_NULL,
86 OVL_UUID_AUTO,
87 OVL_UUID_ON,
88};
89
90enum {
91 OVL_XINO_OFF,
92 OVL_XINO_AUTO,
93 OVL_XINO_ON,
94};
95
96enum {
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 */
134struct 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 */
145struct 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) */
159struct 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
171static 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
181extern const char *const ovl_xattr_table[][2];
182static 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 */
199static 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
206static 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, NULL);
210
211 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
212 return err;
213}
214
215static 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
224static 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
234static 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), dentry, mode, NULL);
239
240 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
241 return err;
242}
243
244static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs,
245 struct inode *dir,
246 struct dentry *dentry,
247 umode_t mode)
248{
249 struct dentry *ret;
250
251 ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, NULL);
252 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(ret));
253 return ret;
254}
255
256static inline int ovl_do_mknod(struct ovl_fs *ofs,
257 struct inode *dir, struct dentry *dentry,
258 umode_t mode, dev_t dev)
259{
260 int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev, NULL);
261
262 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
263 return err;
264}
265
266static inline int ovl_do_symlink(struct ovl_fs *ofs,
267 struct inode *dir, struct dentry *dentry,
268 const char *oldname)
269{
270 int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname, NULL);
271
272 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
273 return err;
274}
275
276static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
277 void *value, size_t size)
278{
279 int err, len;
280
281 WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
282
283 err = vfs_getxattr(mnt_idmap(mnt: path->mnt), path->dentry,
284 name, value, size);
285 len = (value && err > 0) ? err : 0;
286
287 pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
288 path->dentry, name, min(len, 48), value, size, err);
289 return err;
290}
291
292static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
293 struct dentry *upperdentry,
294 enum ovl_xattr ox, void *value,
295 size_t size)
296{
297 struct path upperpath = {
298 .dentry = upperdentry,
299 .mnt = ovl_upper_mnt(ofs),
300 };
301
302 return ovl_do_getxattr(path: &upperpath, name: ovl_xattr(ofs, ox), value, size);
303}
304
305static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
306 const struct path *path,
307 enum ovl_xattr ox, void *value,
308 size_t size)
309{
310 return ovl_do_getxattr(path, name: ovl_xattr(ofs, ox), value, size);
311}
312
313static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
314 const char *name, const void *value,
315 size_t size, int flags)
316{
317 int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
318 value, size, flags);
319
320 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
321 dentry, name, min((int)size, 48), value, size, flags, err);
322 return err;
323}
324
325static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
326 enum ovl_xattr ox, const void *value,
327 size_t size)
328{
329 return ovl_do_setxattr(ofs, dentry, name: ovl_xattr(ofs, ox), value, size, flags: 0);
330}
331
332static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
333 const char *name)
334{
335 int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
336 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
337 return err;
338}
339
340static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
341 enum ovl_xattr ox)
342{
343 return ovl_do_removexattr(ofs, dentry, name: ovl_xattr(ofs, ox));
344}
345
346static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
347 const char *acl_name, struct posix_acl *acl)
348{
349 return vfs_set_acl(idmap: ovl_upper_mnt_idmap(ofs), dentry, acl_name, kacl: acl);
350}
351
352static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
353 const char *acl_name)
354{
355 return vfs_remove_acl(idmap: ovl_upper_mnt_idmap(ofs), dentry, acl_name);
356}
357
358static inline int ovl_do_rename_rd(struct renamedata *rd)
359{
360 int err;
361
362 pr_debug("rename(%pd2, %pd2, 0x%x)\n", rd->old_dentry, rd->new_dentry,
363 rd->flags);
364 err = vfs_rename(rd);
365 if (err) {
366 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
367 rd->old_dentry, rd->new_dentry, err);
368 }
369 return err;
370}
371
372static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir,
373 struct dentry *olddentry, struct dentry *newdir,
374 struct dentry *newdentry, unsigned int flags)
375{
376 struct renamedata rd = {
377 .mnt_idmap = ovl_upper_mnt_idmap(ofs),
378 .old_parent = olddir,
379 .old_dentry = olddentry,
380 .new_parent = newdir,
381 .new_dentry = newdentry,
382 .flags = flags,
383 };
384
385 return ovl_do_rename_rd(rd: &rd);
386}
387
388static inline int ovl_do_whiteout(struct ovl_fs *ofs,
389 struct inode *dir, struct dentry *dentry)
390{
391 int err = vfs_whiteout(idmap: ovl_upper_mnt_idmap(ofs), dir, dentry);
392 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
393 return err;
394}
395
396static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
397 struct dentry *dentry, umode_t mode)
398{
399 struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
400 struct file *file = kernel_tmpfile_open(idmap: ovl_upper_mnt_idmap(ofs), parentpath: &path,
401 mode, O_LARGEFILE | O_WRONLY,
402 current_cred());
403 int err = PTR_ERR_OR_ZERO(ptr: file);
404
405 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
406 return file;
407}
408
409static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
410 const char *name,
411 struct dentry *base, int len)
412{
413 return lookup_one(ovl_upper_mnt_idmap(ofs), &QSTR_LEN(name, len), base);
414}
415
416static inline struct dentry *ovl_lookup_upper_unlocked(struct ovl_fs *ofs,
417 const char *name,
418 struct dentry *base,
419 int len)
420{
421 return lookup_one_unlocked(idmap: ovl_upper_mnt_idmap(ofs),
422 name: &QSTR_LEN(name, len), base);
423}
424
425static inline struct dentry *ovl_start_creating_upper(struct ovl_fs *ofs,
426 struct dentry *parent,
427 struct qstr *name)
428{
429 return start_creating(idmap: ovl_upper_mnt_idmap(ofs),
430 parent, name);
431}
432
433static inline struct dentry *ovl_start_removing_upper(struct ovl_fs *ofs,
434 struct dentry *parent,
435 struct qstr *name)
436{
437 return start_removing(idmap: ovl_upper_mnt_idmap(ofs),
438 parent, name);
439}
440
441static inline bool ovl_open_flags_need_copy_up(int flags)
442{
443 if (!flags)
444 return false;
445
446 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
447}
448
449/* util.c */
450int ovl_get_write_access(struct dentry *dentry);
451void ovl_put_write_access(struct dentry *dentry);
452void ovl_start_write(struct dentry *dentry);
453void ovl_end_write(struct dentry *dentry);
454int ovl_want_write(struct dentry *dentry);
455void ovl_drop_write(struct dentry *dentry);
456struct dentry *ovl_workdir(struct dentry *dentry);
457const struct cred *ovl_override_creds(struct super_block *sb);
458
459EXTEND_CLASS(override_creds, _ovl, ovl_override_creds(sb), struct super_block *sb)
460
461#define with_ovl_creds(sb) \
462 scoped_class(override_creds_ovl, __UNIQUE_ID(label), sb)
463
464static inline const struct cred *ovl_creds(struct super_block *sb)
465{
466 return OVL_FS(sb)->creator_cred;
467}
468
469int ovl_can_decode_fh(struct super_block *sb);
470struct dentry *ovl_indexdir(struct super_block *sb);
471bool ovl_index_all(struct super_block *sb);
472bool ovl_verify_lower(struct super_block *sb);
473struct ovl_path *ovl_stack_alloc(unsigned int n);
474void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
475void ovl_stack_put(struct ovl_path *stack, unsigned int n);
476void ovl_stack_free(struct ovl_path *stack, unsigned int n);
477struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
478void ovl_free_entry(struct ovl_entry *oe);
479bool ovl_dentry_remote(struct dentry *dentry);
480void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
481void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
482 struct ovl_entry *oe);
483void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
484 struct ovl_entry *oe, unsigned int mask);
485bool ovl_dentry_weird(struct dentry *dentry);
486
487static inline bool ovl_dentry_casefolded(struct dentry *dentry)
488{
489 return sb_has_encoding(sb: dentry->d_sb) && IS_CASEFOLDED(d_inode(dentry));
490}
491
492enum ovl_path_type ovl_path_type(struct dentry *dentry);
493void ovl_path_upper(struct dentry *dentry, struct path *path);
494void ovl_path_lower(struct dentry *dentry, struct path *path);
495void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
496struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
497enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
498enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
499struct dentry *ovl_dentry_upper(struct dentry *dentry);
500struct dentry *ovl_dentry_lower(struct dentry *dentry);
501struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
502int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
503const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
504const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
505struct dentry *ovl_dentry_real(struct dentry *dentry);
506struct dentry *ovl_i_dentry_upper(struct inode *inode);
507struct inode *ovl_inode_upper(struct inode *inode);
508struct inode *ovl_inode_lower(struct inode *inode);
509struct inode *ovl_inode_lowerdata(struct inode *inode);
510struct inode *ovl_inode_real(struct inode *inode);
511struct inode *ovl_inode_realdata(struct inode *inode);
512const char *ovl_lowerdata_redirect(struct inode *inode);
513struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
514void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
515void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
516void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
517bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
518bool ovl_dentry_is_opaque(struct dentry *dentry);
519bool ovl_dentry_is_whiteout(struct dentry *dentry);
520void ovl_dentry_set_opaque(struct dentry *dentry);
521bool ovl_dentry_has_xwhiteouts(struct dentry *dentry);
522void ovl_dentry_set_xwhiteouts(struct dentry *dentry);
523void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
524 const struct ovl_layer *layer);
525bool ovl_dentry_has_upper_alias(struct dentry *dentry);
526void ovl_dentry_set_upper_alias(struct dentry *dentry);
527bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
528bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
529bool ovl_has_upperdata(struct inode *inode);
530void ovl_set_upperdata(struct inode *inode);
531const char *ovl_dentry_get_redirect(struct dentry *dentry);
532void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
533void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
534void ovl_dir_modified(struct dentry *dentry, bool impurity);
535u64 ovl_inode_version_get(struct inode *inode);
536bool ovl_is_whiteout(struct dentry *dentry);
537bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
538struct file *ovl_path_open(const struct path *path, int flags);
539int ovl_copy_up_start(struct dentry *dentry, int flags);
540void ovl_copy_up_end(struct dentry *dentry);
541bool ovl_already_copied_up(struct dentry *dentry, int flags);
542char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
543 enum ovl_xattr ox);
544bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
545bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
546bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
547 const struct path *upperpath);
548
549static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
550 struct dentry *upperdentry)
551{
552 struct path upperpath = {
553 .dentry = upperdentry,
554 .mnt = ovl_upper_mnt(ofs),
555 };
556 return ovl_path_is_whiteout(ofs, path: &upperpath);
557}
558
559static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
560 struct dentry *upperdentry)
561{
562 struct path upperpath = {
563 .dentry = upperdentry,
564 .mnt = ovl_upper_mnt(ofs),
565 };
566 return ovl_path_check_origin_xattr(ofs, path: &upperpath);
567}
568
569int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
570 enum ovl_xattr ox, const void *value, size_t size,
571 int xerr);
572int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
573bool ovl_inuse_trylock(struct dentry *dentry);
574void ovl_inuse_unlock(struct dentry *dentry);
575bool ovl_is_inuse(struct dentry *dentry);
576bool ovl_need_index(struct dentry *dentry);
577int ovl_nlink_start(struct dentry *dentry);
578void ovl_nlink_end(struct dentry *dentry);
579int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *work,
580 struct dentry *upperdir, struct dentry *upper);
581int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path,
582 struct ovl_metacopy *data);
583int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d,
584 struct ovl_metacopy *metacopy);
585bool ovl_is_metacopy_dentry(struct dentry *dentry);
586char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
587int ovl_ensure_verity_loaded(const struct path *path);
588int ovl_validate_verity(struct ovl_fs *ofs,
589 const struct path *metapath,
590 const struct path *datapath);
591int ovl_get_verity_digest(struct ovl_fs *ofs, const struct path *src,
592 struct ovl_metacopy *metacopy);
593int ovl_sync_status(struct ovl_fs *ofs);
594
595static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
596{
597 set_bit(nr: flag, addr: &OVL_I(inode)->flags);
598}
599
600static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
601{
602 clear_bit(nr: flag, addr: &OVL_I(inode)->flags);
603}
604
605static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
606{
607 return test_bit(flag, &OVL_I(inode)->flags);
608}
609
610static inline bool ovl_is_impuredir(struct super_block *sb,
611 struct dentry *upperdentry)
612{
613 struct ovl_fs *ofs = OVL_FS(sb);
614 struct path upperpath = {
615 .dentry = upperdentry,
616 .mnt = ovl_upper_mnt(ofs),
617 };
618
619 return ovl_get_dir_xattr_val(ofs, path: &upperpath, ox: OVL_XATTR_IMPURE) == 'y';
620}
621
622static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs,
623 const struct path *path)
624{
625 return ovl_get_dir_xattr_val(ofs, path, ox: OVL_XATTR_OPAQUE);
626}
627
628static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
629{
630 return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
631}
632
633static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
634{
635 return ofs->config.redirect_mode == OVL_REDIRECT_ON;
636}
637
638static inline bool ovl_origin_uuid(struct ovl_fs *ofs)
639{
640 return ofs->config.uuid != OVL_UUID_OFF;
641}
642
643static inline bool ovl_has_fsid(struct ovl_fs *ofs)
644{
645 return ofs->config.uuid == OVL_UUID_ON ||
646 ofs->config.uuid == OVL_UUID_AUTO;
647}
648
649/*
650 * With xino=auto, we do best effort to keep all inodes on same st_dev and
651 * d_ino consistent with st_ino.
652 * With xino=on, we do the same effort but we warn if we failed.
653 */
654static inline bool ovl_xino_warn(struct ovl_fs *ofs)
655{
656 return ofs->config.xino == OVL_XINO_ON;
657}
658
659/*
660 * To avoid regressions in existing setups with overlay lower offline changes,
661 * we allow lower changes only if none of the new features are used.
662 */
663static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
664{
665 return (!ofs->config.index && !ofs->config.metacopy &&
666 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
667}
668
669/* All layers on same fs? */
670static inline bool ovl_same_fs(struct ovl_fs *ofs)
671{
672 return ofs->xino_mode == 0;
673}
674
675/* All overlay inodes have same st_dev? */
676static inline bool ovl_same_dev(struct ovl_fs *ofs)
677{
678 return ofs->xino_mode >= 0;
679}
680
681static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
682{
683 return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
684}
685
686static inline void ovl_inode_lock(struct inode *inode)
687{
688 mutex_lock(&OVL_I(inode)->lock);
689}
690
691static inline int ovl_inode_lock_interruptible(struct inode *inode)
692{
693 return mutex_lock_interruptible(&OVL_I(inode)->lock);
694}
695
696static inline void ovl_inode_unlock(struct inode *inode)
697{
698 mutex_unlock(lock: &OVL_I(inode)->lock);
699}
700
701
702/* namei.c */
703int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
704
705static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
706{
707 if (fh_len < sizeof(struct ovl_fh))
708 return -EINVAL;
709
710 return ovl_check_fb_len(fb: &fh->fb, fb_len: fh_len - OVL_FH_WIRE_OFFSET);
711}
712
713struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
714 struct vfsmount *mnt, bool connected);
715int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
716 struct dentry *upperdentry, struct ovl_path **stackp);
717int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
718 enum ovl_xattr ox, const struct ovl_fh *fh,
719 bool is_upper, bool set);
720int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
721 enum ovl_xattr ox, struct dentry *real,
722 bool is_upper, bool set);
723struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
724 bool connected);
725int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
726int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
727int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
728 struct qstr *name);
729struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
730struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
731 struct dentry *origin, bool verify);
732int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
733 const struct ovl_layer **layer);
734int ovl_verify_lowerdata(struct dentry *dentry);
735struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
736 unsigned int flags);
737bool ovl_lower_positive(struct dentry *dentry);
738
739static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper,
740 const struct ovl_fh *fh, bool set)
741{
742 return ovl_verify_set_fh(ofs, dentry: upper, ox: OVL_XATTR_ORIGIN, fh, is_upper: false, set);
743}
744
745static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
746 struct dentry *origin, bool set)
747{
748 return ovl_verify_origin_xattr(ofs, dentry: upper, ox: OVL_XATTR_ORIGIN, real: origin,
749 is_upper: false, set);
750}
751
752static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
753 struct dentry *upper, bool set)
754{
755 return ovl_verify_origin_xattr(ofs, dentry: index, ox: OVL_XATTR_UPPER, real: upper,
756 is_upper: true, set);
757}
758
759/* readdir.c */
760extern const struct file_operations ovl_dir_operations;
761struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
762int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
763void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
764 struct list_head *list);
765void ovl_cache_free(struct list_head *list);
766void ovl_dir_cache_free(struct inode *inode);
767int ovl_check_d_type_supported(const struct path *realpath);
768int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent,
769 struct vfsmount *mnt, struct dentry *dentry, int level);
770int ovl_indexdir_cleanup(struct ovl_fs *ofs);
771
772/*
773 * Can we iterate real dir directly?
774 *
775 * Non-merge dir may contain whiteouts from a time it was a merge upper, before
776 * lower dir was removed under it and possibly before it was rotated from upper
777 * to lower layer.
778 */
779static inline bool ovl_dir_is_real(struct inode *dir)
780{
781 return !ovl_test_flag(flag: OVL_WHITEOUTS, inode: dir);
782}
783
784/* inode.c */
785int ovl_set_nlink_upper(struct dentry *dentry);
786int ovl_set_nlink_lower(struct dentry *dentry);
787unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
788 struct dentry *upperdentry,
789 unsigned int fallback);
790int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
791 int mask);
792
793#ifdef CONFIG_FS_POSIX_ACL
794struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
795 struct inode *inode, int type,
796 bool rcu, bool noperm);
797static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
798 bool rcu)
799{
800 return do_ovl_get_acl(idmap: &nop_mnt_idmap, inode, type, rcu, noperm: true);
801}
802static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
803 struct dentry *dentry, int type)
804{
805 return do_ovl_get_acl(idmap, inode: d_inode(dentry), type, rcu: false, noperm: false);
806}
807int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
808 struct posix_acl *acl, int type);
809struct posix_acl *ovl_get_acl_path(const struct path *path,
810 const char *acl_name, bool noperm);
811#else
812#define ovl_get_inode_acl NULL
813#define ovl_get_acl NULL
814#define ovl_set_acl NULL
815static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
816 const char *acl_name,
817 bool noperm)
818{
819 return NULL;
820}
821#endif
822
823int ovl_update_time(struct inode *inode, int flags);
824bool ovl_is_private_xattr(struct super_block *sb, const char *name);
825
826struct ovl_inode_params {
827 struct inode *newinode;
828 struct dentry *upperdentry;
829 struct ovl_entry *oe;
830 bool index;
831 char *redirect;
832 char *lowerdata_redirect;
833};
834void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
835 unsigned long ino, int fsid);
836struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
837struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
838 bool is_upper);
839bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
840struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
841struct inode *ovl_get_inode(struct super_block *sb,
842 struct ovl_inode_params *oip);
843void ovl_copyattr(struct inode *to);
844
845/* vfs fileattr flags read from overlay.protattr xattr to ovl inode */
846#define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE)
847/* vfs fileattr flags copied from real to ovl inode */
848#define OVL_FATTR_I_FLAGS_MASK (OVL_PROT_I_FLAGS_MASK | S_SYNC | S_NOATIME)
849/* vfs inode flags copied from real to ovl inode */
850#define OVL_COPY_I_FLAGS_MASK (OVL_FATTR_I_FLAGS_MASK | S_CASEFOLD)
851
852/*
853 * fileattr flags copied from lower to upper inode on copy up.
854 * We cannot copy up immutable/append-only flags, because that would prevent
855 * linking temp inode to upper dir, so we store them in xattr instead.
856 */
857#define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL)
858#define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
859#define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL)
860#define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
861
862void ovl_check_protattr(struct inode *inode, struct dentry *upper);
863int ovl_set_protattr(struct inode *inode, struct dentry *upper,
864 struct file_kattr *fa);
865
866static inline void ovl_copyflags(struct inode *from, struct inode *to)
867{
868 unsigned int mask = OVL_COPY_I_FLAGS_MASK;
869
870 inode_set_flags(inode: to, flags: from->i_flags & mask, mask);
871}
872
873/* dir.c */
874extern const struct inode_operations ovl_dir_inode_operations;
875int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir,
876 struct dentry *dentry);
877struct ovl_cattr {
878 dev_t rdev;
879 umode_t mode;
880 const char *link;
881 struct dentry *hardlink;
882};
883
884#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
885
886struct dentry *ovl_create_real(struct ovl_fs *ofs,
887 struct dentry *parent, struct dentry *newdentry,
888 struct ovl_cattr *attr);
889int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir, struct dentry *dentry);
890#define OVL_TEMPNAME_SIZE 20
891void ovl_tempname(char name[OVL_TEMPNAME_SIZE]);
892struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
893 struct ovl_cattr *attr);
894
895/* file.c */
896extern const struct file_operations ovl_file_operations;
897int ovl_real_fileattr_get(const struct path *realpath, struct file_kattr *fa);
898int ovl_real_fileattr_set(const struct path *realpath, struct file_kattr *fa);
899int ovl_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
900int ovl_fileattr_set(struct mnt_idmap *idmap,
901 struct dentry *dentry, struct file_kattr *fa);
902struct ovl_file;
903struct ovl_file *ovl_file_alloc(struct file *realfile);
904void ovl_file_free(struct ovl_file *of);
905
906/* copy_up.c */
907int ovl_copy_up(struct dentry *dentry);
908int ovl_copy_up_with_data(struct dentry *dentry);
909int ovl_maybe_copy_up(struct dentry *dentry, int flags);
910int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
911int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
912struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct inode *realinode,
913 bool is_upper);
914struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
915int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
916 struct dentry *upper);
917
918/* export.c */
919extern const struct export_operations ovl_export_operations;
920extern const struct export_operations ovl_export_fid_operations;
921
922/* super.c */
923int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
924
925/* Will this overlay be forced to mount/remount ro? */
926static inline bool ovl_force_readonly(struct ovl_fs *ofs)
927{
928 return (!ovl_upper_mnt(ofs) || !ofs->workdir);
929}
930
931/* xattr.c */
932
933const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
934int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
935 struct iattr *attr);
936int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
937 struct kstat *stat, u32 request_mask, unsigned int flags);
938ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
939

source code of linux/fs/overlayfs/overlayfs.h