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
ovl_do_vfs_getxattr(struct dentry * dentry,const char * name,void * buf,size_t size)203 static inline ssize_t ovl_do_vfs_getxattr(struct dentry *dentry,
204 const char *name, void *buf,
205 size_t size)
206 {
207 return __vfs_getxattr(dentry, d_inode(dentry), name, buf, size,
208 XATTR_NOSECURITY);
209 }
210
211 /* util.c */
212 int ovl_want_write(struct dentry *dentry);
213 void ovl_drop_write(struct dentry *dentry);
214 struct dentry *ovl_workdir(struct dentry *dentry);
215 const struct cred *ovl_override_creds(struct super_block *sb);
216 void ovl_revert_creds(struct super_block *sb, const struct cred *oldcred);
217 struct super_block *ovl_same_sb(struct super_block *sb);
218 int ovl_can_decode_fh(struct super_block *sb);
219 struct dentry *ovl_indexdir(struct super_block *sb);
220 bool ovl_index_all(struct super_block *sb);
221 bool ovl_verify_lower(struct super_block *sb);
222 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
223 bool ovl_dentry_remote(struct dentry *dentry);
224 bool ovl_dentry_weird(struct dentry *dentry);
225 enum ovl_path_type ovl_path_type(struct dentry *dentry);
226 void ovl_path_upper(struct dentry *dentry, struct path *path);
227 void ovl_path_lower(struct dentry *dentry, struct path *path);
228 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
229 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
230 struct dentry *ovl_dentry_upper(struct dentry *dentry);
231 struct dentry *ovl_dentry_lower(struct dentry *dentry);
232 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
233 struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
234 struct dentry *ovl_dentry_real(struct dentry *dentry);
235 struct dentry *ovl_i_dentry_upper(struct inode *inode);
236 struct inode *ovl_inode_upper(struct inode *inode);
237 struct inode *ovl_inode_lower(struct inode *inode);
238 struct inode *ovl_inode_lowerdata(struct inode *inode);
239 struct inode *ovl_inode_real(struct inode *inode);
240 struct inode *ovl_inode_realdata(struct inode *inode);
241 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
242 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
243 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
244 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
245 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
246 bool ovl_dentry_is_opaque(struct dentry *dentry);
247 bool ovl_dentry_is_whiteout(struct dentry *dentry);
248 void ovl_dentry_set_opaque(struct dentry *dentry);
249 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
250 void ovl_dentry_set_upper_alias(struct dentry *dentry);
251 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
252 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
253 bool ovl_has_upperdata(struct inode *inode);
254 void ovl_set_upperdata(struct inode *inode);
255 bool ovl_redirect_dir(struct super_block *sb);
256 const char *ovl_dentry_get_redirect(struct dentry *dentry);
257 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
258 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
259 struct dentry *lowerdentry, struct dentry *lowerdata);
260 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
261 void ovl_dir_modified(struct dentry *dentry, bool impurity);
262 u64 ovl_dentry_version_get(struct dentry *dentry);
263 bool ovl_is_whiteout(struct dentry *dentry);
264 struct file *ovl_path_open(struct path *path, int flags);
265 int ovl_copy_up_start(struct dentry *dentry, int flags);
266 void ovl_copy_up_end(struct dentry *dentry);
267 bool ovl_already_copied_up(struct dentry *dentry, int flags);
268 bool ovl_check_origin_xattr(struct dentry *dentry);
269 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
270 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
271 const char *name, const void *value, size_t size,
272 int xerr);
273 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
274 void ovl_set_flag(unsigned long flag, struct inode *inode);
275 void ovl_clear_flag(unsigned long flag, struct inode *inode);
276 bool ovl_test_flag(unsigned long flag, struct inode *inode);
277 bool ovl_inuse_trylock(struct dentry *dentry);
278 void ovl_inuse_unlock(struct dentry *dentry);
279 bool ovl_is_inuse(struct dentry *dentry);
280 bool ovl_need_index(struct dentry *dentry);
281 int ovl_nlink_start(struct dentry *dentry);
282 void ovl_nlink_end(struct dentry *dentry);
283 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
284 int ovl_check_metacopy_xattr(struct dentry *dentry);
285 bool ovl_is_metacopy_dentry(struct dentry *dentry);
286 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
287 ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
288 size_t padding);
289
ovl_is_impuredir(struct dentry * dentry)290 static inline bool ovl_is_impuredir(struct dentry *dentry)
291 {
292 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
293 }
294
ovl_xino_bits(struct super_block * sb)295 static inline unsigned int ovl_xino_bits(struct super_block *sb)
296 {
297 struct ovl_fs *ofs = sb->s_fs_info;
298
299 return ofs->xino_bits;
300 }
301
ovl_inode_lock(struct inode * inode)302 static inline int ovl_inode_lock(struct inode *inode)
303 {
304 return mutex_lock_interruptible(&OVL_I(inode)->lock);
305 }
306
ovl_inode_unlock(struct inode * inode)307 static inline void ovl_inode_unlock(struct inode *inode)
308 {
309 mutex_unlock(&OVL_I(inode)->lock);
310 }
311
312
313 /* namei.c */
314 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
315 struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
316 bool connected);
317 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
318 struct dentry *upperdentry, struct ovl_path **stackp);
319 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
320 struct dentry *real, bool is_upper, bool set);
321 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
322 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
323 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
324 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
325 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
326 struct dentry *origin, bool verify);
327 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
328 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
329 unsigned int flags);
330 bool ovl_lower_positive(struct dentry *dentry);
331
ovl_verify_origin(struct dentry * upper,struct dentry * origin,bool set)332 static inline int ovl_verify_origin(struct dentry *upper,
333 struct dentry *origin, bool set)
334 {
335 return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
336 }
337
ovl_verify_upper(struct dentry * index,struct dentry * upper,bool set)338 static inline int ovl_verify_upper(struct dentry *index,
339 struct dentry *upper, bool set)
340 {
341 return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
342 }
343
344 /* readdir.c */
345 extern const struct file_operations ovl_dir_operations;
346 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
347 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
348 void ovl_cache_free(struct list_head *list);
349 void ovl_dir_cache_free(struct inode *inode);
350 int ovl_check_d_type_supported(struct path *realpath);
351 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
352 struct dentry *dentry, int level);
353 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
354
355 /* inode.c */
356 int ovl_set_nlink_upper(struct dentry *dentry);
357 int ovl_set_nlink_lower(struct dentry *dentry);
358 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
359 struct dentry *upperdentry,
360 unsigned int fallback);
361 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
362 int ovl_getattr(const struct path *path, struct kstat *stat,
363 u32 request_mask, unsigned int flags);
364 int ovl_permission(struct inode *inode, int mask);
365 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
366 const void *value, size_t size, int flags);
367 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
368 void *value, size_t size, int flags);
369 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
370 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
371 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
372 bool ovl_is_private_xattr(const char *name);
373
374 struct ovl_inode_params {
375 struct inode *newinode;
376 struct dentry *upperdentry;
377 struct ovl_path *lowerpath;
378 struct dentry *index;
379 unsigned int numlower;
380 char *redirect;
381 struct dentry *lowerdata;
382 };
383 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
384 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
385 bool is_upper);
386 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
387 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
388 struct inode *ovl_get_inode(struct super_block *sb,
389 struct ovl_inode_params *oip);
ovl_copyattr(struct inode * from,struct inode * to)390 static inline void ovl_copyattr(struct inode *from, struct inode *to)
391 {
392 to->i_uid = from->i_uid;
393 to->i_gid = from->i_gid;
394 to->i_mode = from->i_mode;
395 to->i_atime = from->i_atime;
396 to->i_mtime = from->i_mtime;
397 to->i_ctime = from->i_ctime;
398 i_size_write(to, i_size_read(from));
399 }
400
ovl_copyflags(struct inode * from,struct inode * to)401 static inline void ovl_copyflags(struct inode *from, struct inode *to)
402 {
403 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
404
405 inode_set_flags(to, from->i_flags & mask, mask);
406 }
407
408 /* dir.c */
409 extern const struct inode_operations ovl_dir_inode_operations;
410 int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
411 struct dentry *dentry);
412 struct ovl_cattr {
413 dev_t rdev;
414 umode_t mode;
415 const char *link;
416 struct dentry *hardlink;
417 };
418
419 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
420
421 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
422 struct ovl_cattr *attr);
423 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
424 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
425
426 /* file.c */
427 extern const struct file_operations ovl_file_operations;
428
429 /* copy_up.c */
430 int ovl_copy_up(struct dentry *dentry);
431 int ovl_copy_up_with_data(struct dentry *dentry);
432 int ovl_copy_up_flags(struct dentry *dentry, int flags);
433 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
434 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
435 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
436 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
437 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
438 struct dentry *upper);
439
440 /* export.c */
441 extern const struct export_operations ovl_export_operations;
442