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ovl: fix documentation of non-standard behavior
[linux-block.git] / fs / overlayfs / overlayfs.h
CommitLineData
e9be9d5e
MS		 1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/kernel.h>
3a1e819b 11#include <linux/uuid.h>
46e5d0a3 12#include <linux/fs.h>
ee023c30 13#include "ovl_entry.h"
e9be9d5e 14
e9be9d5e 15enum ovl_path_type {
38e813db
MS		 16 __OVL_PATH_UPPER = (1 << 0),
17 __OVL_PATH_MERGE = (1 << 1),
59548503 18 __OVL_PATH_ORIGIN = (1 << 2),
e9be9d5e
MS		 19};
20
1afaba1e
MS		 21#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
22#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
59548503 23#define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
d837a49b 24
fe2b7595
AG		 25#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
26#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
02b69b28 27#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
3a1e819b 28#define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
ee1d6d37 29#define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
5f8415d6 30#define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
ad1d615c 31#define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
3a1e819b 32
c62520a8 33enum ovl_inode_flag {
b79e05aa 34 /* Pure upper dir that may contain non pure upper entries */
13c72075 35 OVL_IMPURE,
b79e05aa
AG		 36 /* Non-merge dir that may contain whiteout entries */
37 OVL_WHITEOUTS,
359f392c 38 OVL_INDEX,
13c72075
MS		 39};
40
c62520a8
AG		 41enum ovl_entry_flag {
42 OVL_E_UPPER_ALIAS,
43 OVL_E_OPAQUE,
2ca3c148 44 OVL_E_CONNECTED,
c62520a8
AG		 45};
46
3a1e819b
AG		 47/*
48 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
49 * where:
50 * origin.fh - exported file handle of the lower file
51 * origin.uuid - uuid of the lower filesystem
52 */
53#define OVL_FH_VERSION 0
54#define OVL_FH_MAGIC 0xfb
55
56/* CPU byte order required for fid decoding: */
57#define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
58#define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
54fb347e
AG		 59/* Is the real inode encoded in fid an upper inode? */
60#define OVL_FH_FLAG_PATH_UPPER (1 << 2)
3a1e819b 61
961af647
AG		 62#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
63 OVL_FH_FLAG_PATH_UPPER)
3a1e819b
AG		 64
65#if defined(__LITTLE_ENDIAN)
66#define OVL_FH_FLAG_CPU_ENDIAN 0
67#elif defined(__BIG_ENDIAN)
68#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
69#else
70#error Endianness not defined
71#endif
72
8ed5eec9
AG		 73/* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
74#define OVL_FILEID 0xfb
75
3a1e819b
AG		 76/* On-disk and in-memeory format for redirect by file handle */
77struct ovl_fh {
78 u8 version; /* 0 */
79 u8 magic; /* 0xfb */
80 u8 len; /* size of this header + size of fid */
81 u8 flags; /* OVL_FH_FLAG_* */
82 u8 type; /* fid_type of fid */
01633fd2 83 uuid_t uuid; /* uuid of filesystem */
3a1e819b
AG		 84 u8 fid[0]; /* file identifier */
85} __packed;
e9be9d5e
MS		 86
87static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
88{
89 int err = vfs_rmdir(dir, dentry);
6cf00764 90
e9be9d5e
MS		 91 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
92 return err;
93}
94
95static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
96{
97 int err = vfs_unlink(dir, dentry, NULL);
6cf00764 98
e9be9d5e
MS		 99 pr_debug("unlink(%pd2) = %i\n", dentry, err);
100 return err;
101}
102
103static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
6cf00764 104 struct dentry *new_dentry)
e9be9d5e
MS		 105{
106 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
6cf00764
AG		 107
108 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
e9be9d5e
MS		 109 return err;
110}
111
112static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
6cf00764 113 umode_t mode)
e9be9d5e
MS		 114{
115 int err = vfs_create(dir, dentry, mode, true);
6cf00764
AG		 116
117 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
e9be9d5e
MS		 118 return err;
119}
120
121static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
6cf00764 122 umode_t mode)
e9be9d5e
MS		 123{
124 int err = vfs_mkdir(dir, dentry, mode);
6cf00764 125 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
e9be9d5e
MS		 126 return err;
127}
128
129static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
6cf00764 130 umode_t mode, dev_t dev)
e9be9d5e
MS		 131{
132 int err = vfs_mknod(dir, dentry, mode, dev);
6cf00764
AG		 133
134 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
e9be9d5e
MS		 135 return err;
136}
137
138static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
6cf00764 139 const char *oldname)
e9be9d5e
MS		 140{
141 int err = vfs_symlink(dir, dentry, oldname);
6cf00764
AG		 142
143 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
e9be9d5e
MS		 144 return err;
145}
146
147static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
148 const void *value, size_t size, int flags)
149{
150 int err = vfs_setxattr(dentry, name, value, size, flags);
151 pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
152 dentry, name, (int) size, (char *) value, flags, err);
153 return err;
154}
155
156static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
157{
158 int err = vfs_removexattr(dentry, name);
159 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
160 return err;
161}
162
163static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
164 struct inode *newdir, struct dentry *newdentry,
165 unsigned int flags)
166{
167 int err;
168
6cf00764 169 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
e9be9d5e 170 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
e9be9d5e 171 if (err) {
2773bf00 172 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
e9be9d5e
MS		 173 olddentry, newdentry, err);
174 }
175 return err;
176}
177
178static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
179{
180 int err = vfs_whiteout(dir, dentry);
181 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
182 return err;
183}
184
e7f52429
AG		 185static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
186{
187 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
7879cb43 188 int err = PTR_ERR_OR_ZERO(ret);
e7f52429
AG		 189
190 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
191 return ret;
192}
193
bbb1e54d
MS		 194/* util.c */
195int ovl_want_write(struct dentry *dentry);
196void ovl_drop_write(struct dentry *dentry);
197struct dentry *ovl_workdir(struct dentry *dentry);
198const struct cred *ovl_override_creds(struct super_block *sb);
7bcd74b9 199struct super_block *ovl_same_sb(struct super_block *sb);
e487d889 200int ovl_can_decode_fh(struct super_block *sb);
02bcd157 201struct dentry *ovl_indexdir(struct super_block *sb);
f168f109
AG		 202bool ovl_index_all(struct super_block *sb);
203bool ovl_verify_lower(struct super_block *sb);
bbb1e54d
MS		 204struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
205bool ovl_dentry_remote(struct dentry *dentry);
206bool ovl_dentry_weird(struct dentry *dentry);
e9be9d5e 207enum ovl_path_type ovl_path_type(struct dentry *dentry);
e9be9d5e
MS		 208void ovl_path_upper(struct dentry *dentry, struct path *path);
209void ovl_path_lower(struct dentry *dentry, struct path *path);
210enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
211struct dentry *ovl_dentry_upper(struct dentry *dentry);
212struct dentry *ovl_dentry_lower(struct dentry *dentry);
da309e8c 213struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
e9be9d5e 214struct dentry *ovl_dentry_real(struct dentry *dentry);
1d88f183 215struct dentry *ovl_i_dentry_upper(struct inode *inode);
09d8b586
MS		 216struct inode *ovl_inode_upper(struct inode *inode);
217struct inode *ovl_inode_lower(struct inode *inode);
218struct inode *ovl_inode_real(struct inode *inode);
4edb83bb
MS		 219struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
220void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
c62520a8
AG		 221void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
222void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
223bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
e9be9d5e 224bool ovl_dentry_is_opaque(struct dentry *dentry);
c412ce49 225bool ovl_dentry_is_whiteout(struct dentry *dentry);
5cf5b477 226void ovl_dentry_set_opaque(struct dentry *dentry);
55acc661
MS		 227bool ovl_dentry_has_upper_alias(struct dentry *dentry);
228void ovl_dentry_set_upper_alias(struct dentry *dentry);
a6c60655 229bool ovl_redirect_dir(struct super_block *sb);
a6c60655
MS		 230const char *ovl_dentry_get_redirect(struct dentry *dentry);
231void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
09d8b586
MS		 232void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
233 struct dentry *lowerdentry);
234void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
d9854c87 235void ovl_dir_modified(struct dentry *dentry, bool impurity);
bbb1e54d
MS		 236u64 ovl_dentry_version_get(struct dentry *dentry);
237bool ovl_is_whiteout(struct dentry *dentry);
e9be9d5e 238struct file *ovl_path_open(struct path *path, int flags);
39d3d60a
AG		 239int ovl_copy_up_start(struct dentry *dentry);
240void ovl_copy_up_end(struct dentry *dentry);
b79e05aa 241bool ovl_check_origin_xattr(struct dentry *dentry);
f3a15685
AG		 242bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
243int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
244 const char *name, const void *value, size_t size,
245 int xerr);
246int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
13c72075 247void ovl_set_flag(unsigned long flag, struct inode *inode);
4edb83bb 248void ovl_clear_flag(unsigned long flag, struct inode *inode);
13c72075 249bool ovl_test_flag(unsigned long flag, struct inode *inode);
ad0af710
AG		 250bool ovl_inuse_trylock(struct dentry *dentry);
251void ovl_inuse_unlock(struct dentry *dentry);
24b33ee1 252bool ovl_need_index(struct dentry *dentry);
5f8415d6
AG		 253int ovl_nlink_start(struct dentry *dentry, bool *locked);
254void ovl_nlink_end(struct dentry *dentry, bool locked);
5820dc08 255int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
f3a15685
AG		 256
257static inline bool ovl_is_impuredir(struct dentry *dentry)
258{
259 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
260}
261
e487d889
AG		 262static inline unsigned int ovl_xino_bits(struct super_block *sb)
263{
264 struct ovl_fs *ofs = sb->s_fs_info;
265
266 return ofs->xino_bits;
267}
268
e9be9d5e 269
bbb1e54d 270/* namei.c */
8556a420 271int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
8a22efa1
AG		 272struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
273 bool connected);
274int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
f941866f 275 struct dentry *upperdentry, struct ovl_path **stackp);
05122443
AG		 276int ovl_verify_set_fh(struct dentry *dentry, const char *name,
277 struct dentry *real, bool is_upper, bool set);
3b0bfc6e 278struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
1eff1a1d 279int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
359f392c 280int ovl_get_index_name(struct dentry *origin, struct qstr *name);
91ffe7be 281struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
06170154
AG		 282struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
283 struct dentry *origin, bool verify);
bbb1e54d 284int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
1eff1a1d
AG		 285struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
286 unsigned int flags);
bbb1e54d 287bool ovl_lower_positive(struct dentry *dentry);
e9be9d5e 288
05122443
AG		 289static inline int ovl_verify_origin(struct dentry *upper,
290 struct dentry *origin, bool set)
291{
292 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
293}
294
ad1d615c
AG		 295static inline int ovl_verify_upper(struct dentry *index,
296 struct dentry *upper, bool set)
297{
298 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
299}
300
e9be9d5e
MS		 301/* readdir.c */
302extern const struct file_operations ovl_dir_operations;
303int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
304void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
305void ovl_cache_free(struct list_head *list);
4edb83bb 306void ovl_dir_cache_free(struct inode *inode);
45aebeaf 307int ovl_check_d_type_supported(struct path *realpath);
eea2fb48
MS		 308void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
309 struct dentry *dentry, int level);
1eff1a1d 310int ovl_indexdir_cleanup(struct ovl_fs *ofs);
e9be9d5e
MS		 311
312/* inode.c */
5f8415d6
AG		 313int ovl_set_nlink_upper(struct dentry *dentry);
314int ovl_set_nlink_lower(struct dentry *dentry);
caf70cb2
AG		 315unsigned int ovl_get_nlink(struct dentry *lowerdentry,
316 struct dentry *upperdentry,
317 unsigned int fallback);
e9be9d5e 318int ovl_setattr(struct dentry *dentry, struct iattr *attr);
5b712091
MS		 319int ovl_getattr(const struct path *path, struct kstat *stat,
320 u32 request_mask, unsigned int flags);
e9be9d5e 321int ovl_permission(struct inode *inode, int mask);
1d88f183
MS		 322int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
323 const void *value, size_t size, int flags);
324int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
0eb45fc3 325 void *value, size_t size);
e9be9d5e 326ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
39a25b2b 327struct posix_acl *ovl_get_acl(struct inode *inode, int type);
2d902671 328int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
95582b00 329int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
0956254a 330bool ovl_is_private_xattr(const char *name);
e9be9d5e 331
ac6a52eb 332struct ovl_inode_params {
01b39dcc 333 struct inode *newinode;
ac6a52eb
VG		 334 struct dentry *upperdentry;
335 struct ovl_path *lowerpath;
336 struct dentry *index;
337 unsigned int numlower;
338};
ca4c8a3a 339struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
4b91c30a
AG		 340struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
341 bool is_upper);
ac6a52eb
VG		 342struct inode *ovl_get_inode(struct super_block *sb,
343 struct ovl_inode_params *oip);
e9be9d5e
MS		 344static inline void ovl_copyattr(struct inode *from, struct inode *to)
345{
346 to->i_uid = from->i_uid;
347 to->i_gid = from->i_gid;
07a2daab 348 to->i_mode = from->i_mode;
d719e8f2
MS		 349 to->i_atime = from->i_atime;
350 to->i_mtime = from->i_mtime;
351 to->i_ctime = from->i_ctime;
46e5d0a3 352 i_size_write(to, i_size_read(from));
e9be9d5e
MS		 353}
354
4f357295
MS		 355static inline void ovl_copyflags(struct inode *from, struct inode *to)
356{
357 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
358
359 inode_set_flags(to, from->i_flags & mask, mask);
360}
361
e9be9d5e
MS		 362/* dir.c */
363extern const struct inode_operations ovl_dir_inode_operations;
e7dd0e71
AG		 364int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
365 struct dentry *dentry);
471ec5dc 366struct ovl_cattr {
32a3d848
AV		 367 dev_t rdev;
368 umode_t mode;
369 const char *link;
471ec5dc 370 struct dentry *hardlink;
32a3d848 371};
471ec5dc
AG		 372
373#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
374
95a1c815
MS		 375struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
376 struct ovl_cattr *attr);
415543d5 377int ovl_cleanup(struct inode *dir, struct dentry *dentry);
137ec526 378struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
e9be9d5e 379
d1d04ef8
MS		 380/* file.c */
381extern const struct file_operations ovl_file_operations;
382
e9be9d5e
MS		 383/* copy_up.c */
384int ovl_copy_up(struct dentry *dentry);
9aba6521 385int ovl_copy_up_flags(struct dentry *dentry, int flags);
e9be9d5e
MS		 386int ovl_copy_xattr(struct dentry *old, struct dentry *new);
387int ovl_set_attr(struct dentry *upper, struct kstat *stat);
5b2cccd3 388struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
9678e630
AG		 389int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
390 struct dentry *upper);
8ed5eec9
AG		 391
392/* export.c */
393extern const struct export_operations ovl_export_operations;
Linux 6.x block layer and io_uring tree(s)