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 "ovl_entry.h"
11
12 enum ovl_path_type {
13 __OVL_PATH_UPPER = (1 << 0),
14 __OVL_PATH_MERGE = (1 << 1),
15 __OVL_PATH_ORIGIN = (1 << 2),
16 };
17
18 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
19 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
20 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
21
22 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
23 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
24 #define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
25 #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
26 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
27 #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
28 #define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
29 #define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
30
31 enum ovl_inode_flag {
32 /* Pure upper dir that may contain non pure upper entries */
33 OVL_IMPURE,
34 /* Non-merge dir that may contain whiteout entries */
35 OVL_WHITEOUTS,
36 OVL_INDEX,
37 OVL_UPPERDATA,
38 /* Inode number will remain constant over copy up. */
39 OVL_CONST_INO,
40 };
41
42 enum ovl_entry_flag {
43 OVL_E_UPPER_ALIAS,
44 OVL_E_OPAQUE,
45 OVL_E_CONNECTED,
46 };
47
48 /*
49 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
50 * where:
51 * origin.fh - exported file handle of the lower file
52 * origin.uuid - uuid of the lower filesystem
53 */
54 #define OVL_FH_VERSION 0
55 #define OVL_FH_MAGIC 0xfb
56
57 /* CPU byte order required for fid decoding: */
58 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
59 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
60 /* Is the real inode encoded in fid an upper inode? */
61 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
62
63 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
64 OVL_FH_FLAG_PATH_UPPER)
65
66 #if defined(__LITTLE_ENDIAN)
67 #define OVL_FH_FLAG_CPU_ENDIAN 0
68 #elif defined(__BIG_ENDIAN)
69 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
70 #else
71 #error Endianness not defined
72 #endif
73
74 /* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
75 #define OVL_FILEID 0xfb
76
77 /* On-disk and in-memeory format for redirect by file handle */
78 struct ovl_fh {
79 u8 version; /* 0 */
80 u8 magic; /* 0xfb */
81 u8 len; /* size of this header + size of fid */
82 u8 flags; /* OVL_FH_FLAG_* */
83 u8 type; /* fid_type of fid */
84 uuid_t uuid; /* uuid of filesystem */
85 u8 fid[0]; /* file identifier */
86 } __packed;
87
ovl_do_rmdir(struct inode * dir,struct dentry * dentry)88 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
89 {
90 int err = vfs_rmdir(dir, dentry);
91
92 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
93 return err;
94 }
95
ovl_do_unlink(struct inode * dir,struct dentry * dentry)96 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
97 {
98 int err = vfs_unlink(dir, dentry, NULL);
99
100 pr_debug("unlink(%pd2) = %i\n", dentry, err);
101 return err;
102 }
103
ovl_do_link(struct dentry * old_dentry,struct inode * dir,struct dentry * new_dentry)104 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
105 struct dentry *new_dentry)
106 {
107 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
108
109 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
110 return err;
111 }
112
ovl_do_create(struct inode * dir,struct dentry * dentry,umode_t mode)113 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
114 umode_t mode)
115 {
116 int err = vfs_create(dir, dentry, mode, true);
117
118 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
119 return err;
120 }
121
ovl_do_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)122 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
123 umode_t mode)
124 {
125 int err = vfs_mkdir(dir, dentry, mode);
126 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
127 return err;
128 }
129
ovl_do_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)130 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
131 umode_t mode, dev_t dev)
132 {
133 int err = vfs_mknod(dir, dentry, mode, dev);
134
135 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
136 return err;
137 }
138
ovl_do_symlink(struct inode * dir,struct dentry * dentry,const char * oldname)139 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
140 const char *oldname)
141 {
142 int err = vfs_symlink(dir, dentry, oldname);
143
144 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
145 return err;
146 }
147
ovl_do_setxattr(struct dentry * dentry,const char * name,const void * value,size_t size,int flags)148 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
149 const void *value, size_t size, int flags)
150 {
151 int err = vfs_setxattr(dentry, name, value, size, flags);
152 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
153 dentry, name, min((int)size, 48), value, size, flags, err);
154 return err;
155 }
156
ovl_do_removexattr(struct dentry * dentry,const char * name)157 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
158 {
159 int err = vfs_removexattr(dentry, name);
160 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
161 return err;
162 }
163
ovl_do_rename(struct inode * olddir,struct dentry * olddentry,struct inode * newdir,struct dentry * newdentry,unsigned int flags)164 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
165 struct inode *newdir, struct dentry *newdentry,
166 unsigned int flags)
167 {
168 int err;
169
170 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
171 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
172 if (err) {
173 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
174 olddentry, newdentry, err);
175 }
176 return err;
177 }
178
ovl_do_whiteout(struct inode * dir,struct dentry * dentry)179 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
180 {
181 int err = vfs_whiteout(dir, dentry);
182 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
183 return err;
184 }
185
ovl_do_tmpfile(struct dentry * dentry,umode_t mode)186 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
187 {
188 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
189 int err = PTR_ERR_OR_ZERO(ret);
190
191 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
192 return ret;
193 }
194
ovl_open_flags_need_copy_up(int flags)195 static inline bool ovl_open_flags_need_copy_up(int flags)
196 {
197 if (!flags)
198 return false;
199
200 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
201 }
202
203 /* util.c */
204 int ovl_want_write(struct dentry *dentry);
205 void ovl_drop_write(struct dentry *dentry);
206 struct dentry *ovl_workdir(struct dentry *dentry);
207 const struct cred *ovl_override_creds(struct super_block *sb);
208 struct super_block *ovl_same_sb(struct super_block *sb);
209 int ovl_can_decode_fh(struct super_block *sb);
210 struct dentry *ovl_indexdir(struct super_block *sb);
211 bool ovl_index_all(struct super_block *sb);
212 bool ovl_verify_lower(struct super_block *sb);
213 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
214 bool ovl_dentry_remote(struct dentry *dentry);
215 bool ovl_dentry_weird(struct dentry *dentry);
216 enum ovl_path_type ovl_path_type(struct dentry *dentry);
217 void ovl_path_upper(struct dentry *dentry, struct path *path);
218 void ovl_path_lower(struct dentry *dentry, struct path *path);
219 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
220 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
221 struct dentry *ovl_dentry_upper(struct dentry *dentry);
222 struct dentry *ovl_dentry_lower(struct dentry *dentry);
223 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
224 struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
225 struct dentry *ovl_dentry_real(struct dentry *dentry);
226 struct dentry *ovl_i_dentry_upper(struct inode *inode);
227 struct inode *ovl_inode_upper(struct inode *inode);
228 struct inode *ovl_inode_lower(struct inode *inode);
229 struct inode *ovl_inode_lowerdata(struct inode *inode);
230 struct inode *ovl_inode_real(struct inode *inode);
231 struct inode *ovl_inode_realdata(struct inode *inode);
232 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
233 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
234 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
235 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
236 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
237 bool ovl_dentry_is_opaque(struct dentry *dentry);
238 bool ovl_dentry_is_whiteout(struct dentry *dentry);
239 void ovl_dentry_set_opaque(struct dentry *dentry);
240 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
241 void ovl_dentry_set_upper_alias(struct dentry *dentry);
242 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
243 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
244 bool ovl_has_upperdata(struct inode *inode);
245 void ovl_set_upperdata(struct inode *inode);
246 bool ovl_redirect_dir(struct super_block *sb);
247 const char *ovl_dentry_get_redirect(struct dentry *dentry);
248 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
249 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
250 struct dentry *lowerdentry, struct dentry *lowerdata);
251 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
252 void ovl_dir_modified(struct dentry *dentry, bool impurity);
253 u64 ovl_dentry_version_get(struct dentry *dentry);
254 bool ovl_is_whiteout(struct dentry *dentry);
255 struct file *ovl_path_open(struct path *path, int flags);
256 int ovl_copy_up_start(struct dentry *dentry, int flags);
257 void ovl_copy_up_end(struct dentry *dentry);
258 bool ovl_already_copied_up(struct dentry *dentry, int flags);
259 bool ovl_check_origin_xattr(struct dentry *dentry);
260 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
261 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
262 const char *name, const void *value, size_t size,
263 int xerr);
264 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
265 void ovl_set_flag(unsigned long flag, struct inode *inode);
266 void ovl_clear_flag(unsigned long flag, struct inode *inode);
267 bool ovl_test_flag(unsigned long flag, struct inode *inode);
268 bool ovl_inuse_trylock(struct dentry *dentry);
269 void ovl_inuse_unlock(struct dentry *dentry);
270 bool ovl_is_inuse(struct dentry *dentry);
271 bool ovl_need_index(struct dentry *dentry);
272 int ovl_nlink_start(struct dentry *dentry);
273 void ovl_nlink_end(struct dentry *dentry);
274 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
275 int ovl_check_metacopy_xattr(struct dentry *dentry);
276 bool ovl_is_metacopy_dentry(struct dentry *dentry);
277 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
278 ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
279 size_t padding);
280
ovl_is_impuredir(struct dentry * dentry)281 static inline bool ovl_is_impuredir(struct dentry *dentry)
282 {
283 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
284 }
285
ovl_xino_bits(struct super_block * sb)286 static inline unsigned int ovl_xino_bits(struct super_block *sb)
287 {
288 struct ovl_fs *ofs = sb->s_fs_info;
289
290 return ofs->xino_bits;
291 }
292
ovl_inode_lock(struct inode * inode)293 static inline int ovl_inode_lock(struct inode *inode)
294 {
295 return mutex_lock_interruptible(&OVL_I(inode)->lock);
296 }
297
ovl_inode_unlock(struct inode * inode)298 static inline void ovl_inode_unlock(struct inode *inode)
299 {
300 mutex_unlock(&OVL_I(inode)->lock);
301 }
302
303
304 /* namei.c */
305 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
306 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
307 bool connected);
308 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
309 struct dentry *upperdentry, struct ovl_path **stackp);
310 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
311 struct dentry *real, bool is_upper, bool set);
312 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
313 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
314 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
315 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
316 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
317 struct dentry *origin, bool verify);
318 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
319 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
320 unsigned int flags);
321 bool ovl_lower_positive(struct dentry *dentry);
322
ovl_verify_origin(struct dentry * upper,struct dentry * origin,bool set)323 static inline int ovl_verify_origin(struct dentry *upper,
324 struct dentry *origin, bool set)
325 {
326 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
327 }
328
ovl_verify_upper(struct dentry * index,struct dentry * upper,bool set)329 static inline int ovl_verify_upper(struct dentry *index,
330 struct dentry *upper, bool set)
331 {
332 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
333 }
334
335 /* readdir.c */
336 extern const struct file_operations ovl_dir_operations;
337 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
338 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
339 void ovl_cache_free(struct list_head *list);
340 void ovl_dir_cache_free(struct inode *inode);
341 int ovl_check_d_type_supported(struct path *realpath);
342 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
343 struct dentry *dentry, int level);
344 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
345
346 /* inode.c */
347 int ovl_set_nlink_upper(struct dentry *dentry);
348 int ovl_set_nlink_lower(struct dentry *dentry);
349 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
350 struct dentry *upperdentry,
351 unsigned int fallback);
352 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
353 int ovl_getattr(const struct path *path, struct kstat *stat,
354 u32 request_mask, unsigned int flags);
355 int ovl_permission(struct inode *inode, int mask);
356 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
357 const void *value, size_t size, int flags);
358 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
359 void *value, size_t size);
360 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
361 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
362 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
363 bool ovl_is_private_xattr(const char *name);
364
365 struct ovl_inode_params {
366 struct inode *newinode;
367 struct dentry *upperdentry;
368 struct ovl_path *lowerpath;
369 struct dentry *index;
370 unsigned int numlower;
371 char *redirect;
372 struct dentry *lowerdata;
373 };
374 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
375 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
376 bool is_upper);
377 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
378 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
379 struct inode *ovl_get_inode(struct super_block *sb,
380 struct ovl_inode_params *oip);
ovl_copyattr(struct inode * from,struct inode * to)381 static inline void ovl_copyattr(struct inode *from, struct inode *to)
382 {
383 to->i_uid = from->i_uid;
384 to->i_gid = from->i_gid;
385 to->i_mode = from->i_mode;
386 to->i_atime = from->i_atime;
387 to->i_mtime = from->i_mtime;
388 to->i_ctime = from->i_ctime;
389 i_size_write(to, i_size_read(from));
390 }
391
ovl_copyflags(struct inode * from,struct inode * to)392 static inline void ovl_copyflags(struct inode *from, struct inode *to)
393 {
394 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
395
396 inode_set_flags(to, from->i_flags & mask, mask);
397 }
398
399 /* dir.c */
400 extern const struct inode_operations ovl_dir_inode_operations;
401 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
402 struct dentry *dentry);
403 struct ovl_cattr {
404 dev_t rdev;
405 umode_t mode;
406 const char *link;
407 struct dentry *hardlink;
408 };
409
410 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
411
412 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
413 struct ovl_cattr *attr);
414 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
415 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
416
417 /* file.c */
418 extern const struct file_operations ovl_file_operations;
419
420 /* copy_up.c */
421 int ovl_copy_up(struct dentry *dentry);
422 int ovl_copy_up_with_data(struct dentry *dentry);
423 int ovl_copy_up_flags(struct dentry *dentry, int flags);
424 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
425 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
426 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
427 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
428 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
429 struct dentry *upper);
430
431 /* export.c */
432 extern const struct export_operations ovl_export_operations;
433
