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
13 enum ovl_path_type {
14 __OVL_PATH_UPPER = (1 << 0),
15 __OVL_PATH_MERGE = (1 << 1),
16 __OVL_PATH_ORIGIN = (1 << 2),
17 };
18
19 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
20 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
21 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
22
23 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
24 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
25 #define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
26 #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
27 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
28 #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
29
30 enum ovl_flag {
31 OVL_IMPURE,
32 OVL_INDEX,
33 };
34
35 /*
36 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
37 * where:
38 * origin.fh - exported file handle of the lower file
39 * origin.uuid - uuid of the lower filesystem
40 */
41 #define OVL_FH_VERSION 0
42 #define OVL_FH_MAGIC 0xfb
43
44 /* CPU byte order required for fid decoding: */
45 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
46 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
47 /* Is the real inode encoded in fid an upper inode? */
48 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
49
50 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
51 OVL_FH_FLAG_PATH_UPPER)
52
53 #if defined(__LITTLE_ENDIAN)
54 #define OVL_FH_FLAG_CPU_ENDIAN 0
55 #elif defined(__BIG_ENDIAN)
56 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
57 #else
58 #error Endianness not defined
59 #endif
60
61 /* On-disk and in-memeory format for redirect by file handle */
62 struct ovl_fh {
63 u8 version; /* 0 */
64 u8 magic; /* 0xfb */
65 u8 len; /* size of this header + size of fid */
66 u8 flags; /* OVL_FH_FLAG_* */
67 u8 type; /* fid_type of fid */
68 uuid_t uuid; /* uuid of filesystem */
69 u8 fid[0]; /* file identifier */
70 } __packed;
71
ovl_do_rmdir(struct inode * dir,struct dentry * dentry)72 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
73 {
74 int err = vfs_rmdir(dir, dentry);
75 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
76 return err;
77 }
78
ovl_do_unlink(struct inode * dir,struct dentry * dentry)79 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
80 {
81 int err = vfs_unlink(dir, dentry, NULL);
82 pr_debug("unlink(%pd2) = %i\n", dentry, err);
83 return err;
84 }
85
ovl_do_link(struct dentry * old_dentry,struct inode * dir,struct dentry * new_dentry,bool debug)86 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
87 struct dentry *new_dentry, bool debug)
88 {
89 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
90 if (debug) {
91 pr_debug("link(%pd2, %pd2) = %i\n",
92 old_dentry, new_dentry, err);
93 }
94 return err;
95 }
96
ovl_do_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool debug)97 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
98 umode_t mode, bool debug)
99 {
100 int err = vfs_create(dir, dentry, mode, true);
101 if (debug)
102 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
103 return err;
104 }
105
ovl_do_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode,bool debug)106 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
107 umode_t mode, bool debug)
108 {
109 int err = vfs_mkdir(dir, dentry, mode);
110 if (debug)
111 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
112 return err;
113 }
114
ovl_do_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev,bool debug)115 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
116 umode_t mode, dev_t dev, bool debug)
117 {
118 int err = vfs_mknod(dir, dentry, mode, dev);
119 if (debug) {
120 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
121 dentry, mode, dev, err);
122 }
123 return err;
124 }
125
ovl_do_symlink(struct inode * dir,struct dentry * dentry,const char * oldname,bool debug)126 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
127 const char *oldname, bool debug)
128 {
129 int err = vfs_symlink(dir, dentry, oldname);
130 if (debug)
131 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
132 return err;
133 }
134
ovl_do_setxattr(struct dentry * dentry,const char * name,const void * value,size_t size,int flags)135 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
136 const void *value, size_t size, int flags)
137 {
138 int err = vfs_setxattr(dentry, name, value, size, flags);
139 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
140 dentry, name, min((int)size, 48), value, size, flags, err);
141 return err;
142 }
143
ovl_do_removexattr(struct dentry * dentry,const char * name)144 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
145 {
146 int err = vfs_removexattr(dentry, name);
147 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
148 return err;
149 }
150
ovl_do_rename(struct inode * olddir,struct dentry * olddentry,struct inode * newdir,struct dentry * newdentry,unsigned int flags)151 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
152 struct inode *newdir, struct dentry *newdentry,
153 unsigned int flags)
154 {
155 int err;
156
157 pr_debug("rename(%pd2, %pd2, 0x%x)\n",
158 olddentry, newdentry, flags);
159
160 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
161
162 if (err) {
163 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
164 olddentry, newdentry, err);
165 }
166 return err;
167 }
168
ovl_do_whiteout(struct inode * dir,struct dentry * dentry)169 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
170 {
171 int err = vfs_whiteout(dir, dentry);
172 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
173 return err;
174 }
175
ovl_do_tmpfile(struct dentry * dentry,umode_t mode)176 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
177 {
178 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
179 int err = IS_ERR(ret) ? PTR_ERR(ret) : 0;
180
181 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
182 return ret;
183 }
184
185 /* util.c */
186 int ovl_want_write(struct dentry *dentry);
187 void ovl_drop_write(struct dentry *dentry);
188 struct dentry *ovl_workdir(struct dentry *dentry);
189 const struct cred *ovl_override_creds(struct super_block *sb);
190 void ovl_revert_creds(const struct cred *oldcred);
191 ssize_t ovl_vfs_getxattr(struct dentry *dentry, const char *name, void *buf,
192 size_t size);
193 struct super_block *ovl_same_sb(struct super_block *sb);
194 bool ovl_can_decode_fh(struct super_block *sb);
195 struct dentry *ovl_indexdir(struct super_block *sb);
196 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
197 bool ovl_dentry_remote(struct dentry *dentry);
198 bool ovl_dentry_weird(struct dentry *dentry);
199 enum ovl_path_type ovl_path_type(struct dentry *dentry);
200 void ovl_path_upper(struct dentry *dentry, struct path *path);
201 void ovl_path_lower(struct dentry *dentry, struct path *path);
202 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
203 struct dentry *ovl_dentry_upper(struct dentry *dentry);
204 struct dentry *ovl_dentry_lower(struct dentry *dentry);
205 struct dentry *ovl_dentry_real(struct dentry *dentry);
206 struct dentry *ovl_i_dentry_upper(struct inode *inode);
207 struct inode *ovl_inode_upper(struct inode *inode);
208 struct inode *ovl_inode_lower(struct inode *inode);
209 struct inode *ovl_inode_real(struct inode *inode);
210 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
211 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
212 bool ovl_dentry_is_opaque(struct dentry *dentry);
213 bool ovl_dentry_is_whiteout(struct dentry *dentry);
214 void ovl_dentry_set_opaque(struct dentry *dentry);
215 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
216 void ovl_dentry_set_upper_alias(struct dentry *dentry);
217 bool ovl_redirect_dir(struct super_block *sb);
218 const char *ovl_dentry_get_redirect(struct dentry *dentry);
219 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
220 void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
221 struct dentry *lowerdentry);
222 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
223 void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
224 u64 ovl_dentry_version_get(struct dentry *dentry);
225 bool ovl_is_whiteout(struct dentry *dentry);
226 struct file *ovl_path_open(struct path *path, int flags);
227 int ovl_copy_up_start(struct dentry *dentry);
228 void ovl_copy_up_end(struct dentry *dentry);
229 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
230 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
231 const char *name, const void *value, size_t size,
232 int xerr);
233 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
234 void ovl_set_flag(unsigned long flag, struct inode *inode);
235 void ovl_clear_flag(unsigned long flag, struct inode *inode);
236 bool ovl_test_flag(unsigned long flag, struct inode *inode);
237 bool ovl_inuse_trylock(struct dentry *dentry);
238 void ovl_inuse_unlock(struct dentry *dentry);
239 int ovl_nlink_start(struct dentry *dentry, bool *locked);
240 void ovl_nlink_end(struct dentry *dentry, bool locked);
241 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
242
ovl_is_impuredir(struct dentry * dentry)243 static inline bool ovl_is_impuredir(struct dentry *dentry)
244 {
245 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
246 }
247
248
249 /* namei.c */
250 int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt,
251 struct dentry *origin, bool is_upper, bool set);
252 int ovl_verify_index(struct dentry *index, struct path *lowerstack,
253 unsigned int numlower);
254 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
255 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
256 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
257 bool ovl_lower_positive(struct dentry *dentry);
258
259 /* readdir.c */
260 extern const struct file_operations ovl_dir_operations;
261 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
262 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
263 void ovl_cache_free(struct list_head *list);
264 void ovl_dir_cache_free(struct inode *inode);
265 int ovl_check_d_type_supported(struct path *realpath);
266 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
267 struct dentry *dentry, int level);
268 int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
269 struct path *lowerstack, unsigned int numlower);
270
271 /* inode.c */
272 int ovl_set_nlink_upper(struct dentry *dentry);
273 int ovl_set_nlink_lower(struct dentry *dentry);
274 unsigned int ovl_get_nlink(struct dentry *lowerdentry,
275 struct dentry *upperdentry,
276 unsigned int fallback);
277 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
278 int ovl_getattr(const struct path *path, struct kstat *stat,
279 u32 request_mask, unsigned int flags);
280 int ovl_permission(struct inode *inode, int mask);
281 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
282 const void *value, size_t size, int flags);
283 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
284 void *value, size_t size);
285 int __ovl_xattr_get(struct dentry *dentry, struct inode *inode,
286 const char *name, void *value, size_t size);
287 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
288 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
289 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
290 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
291 bool ovl_is_private_xattr(const char *name);
292
293 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
294 struct inode *ovl_get_inode(struct dentry *dentry, struct dentry *upperdentry,
295 struct dentry *index);
ovl_copyattr(struct inode * from,struct inode * to)296 static inline void ovl_copyattr(struct inode *from, struct inode *to)
297 {
298 to->i_uid = from->i_uid;
299 to->i_gid = from->i_gid;
300 to->i_mode = from->i_mode;
301 to->i_atime = from->i_atime;
302 to->i_mtime = from->i_mtime;
303 to->i_ctime = from->i_ctime;
304 }
305
306 /* dir.c */
307 extern const struct inode_operations ovl_dir_inode_operations;
308 struct dentry *ovl_lookup_temp(struct dentry *workdir);
309 struct cattr {
310 dev_t rdev;
311 umode_t mode;
312 const char *link;
313 };
314 int ovl_create_real(struct inode *dir, struct dentry *newdentry,
315 struct cattr *attr,
316 struct dentry *hardlink, bool debug);
317 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
318
319 /* copy_up.c */
320 int ovl_copy_up(struct dentry *dentry);
321 int ovl_copy_up_flags(struct dentry *dentry, int flags);
322 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
323 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
324 struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper);
325