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

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