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