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 <linux/namei.h>
11 #include "ovl_entry.h"
12 
13 #undef pr_fmt
14 #define pr_fmt(fmt) "overlayfs: " fmt
15 
16 enum ovl_path_type {
17 	__OVL_PATH_UPPER	= (1 << 0),
18 	__OVL_PATH_MERGE	= (1 << 1),
19 	__OVL_PATH_ORIGIN	= (1 << 2),
20 };
21 
22 #define OVL_TYPE_UPPER(type)	((type) & __OVL_PATH_UPPER)
23 #define OVL_TYPE_MERGE(type)	((type) & __OVL_PATH_MERGE)
24 #define OVL_TYPE_ORIGIN(type)	((type) & __OVL_PATH_ORIGIN)
25 
26 #define OVL_XATTR_NAMESPACE "overlay."
27 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
28 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
29 
30 enum ovl_xattr {
31 	OVL_XATTR_OPAQUE,
32 	OVL_XATTR_REDIRECT,
33 	OVL_XATTR_ORIGIN,
34 	OVL_XATTR_IMPURE,
35 	OVL_XATTR_NLINK,
36 	OVL_XATTR_UPPER,
37 	OVL_XATTR_METACOPY,
38 	OVL_XATTR_PROTATTR,
39 };
40 
41 enum ovl_inode_flag {
42 	/* Pure upper dir that may contain non pure upper entries */
43 	OVL_IMPURE,
44 	/* Non-merge dir that may contain whiteout entries */
45 	OVL_WHITEOUTS,
46 	OVL_INDEX,
47 	OVL_UPPERDATA,
48 	/* Inode number will remain constant over copy up. */
49 	OVL_CONST_INO,
50 };
51 
52 enum ovl_entry_flag {
53 	OVL_E_UPPER_ALIAS,
54 	OVL_E_OPAQUE,
55 	OVL_E_CONNECTED,
56 };
57 
58 enum {
59 	OVL_XINO_OFF,
60 	OVL_XINO_AUTO,
61 	OVL_XINO_ON,
62 };
63 
64 /*
65  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
66  * where:
67  * origin.fh	- exported file handle of the lower file
68  * origin.uuid	- uuid of the lower filesystem
69  */
70 #define OVL_FH_VERSION	0
71 #define OVL_FH_MAGIC	0xfb
72 
73 /* CPU byte order required for fid decoding:  */
74 #define OVL_FH_FLAG_BIG_ENDIAN	(1 << 0)
75 #define OVL_FH_FLAG_ANY_ENDIAN	(1 << 1)
76 /* Is the real inode encoded in fid an upper inode? */
77 #define OVL_FH_FLAG_PATH_UPPER	(1 << 2)
78 
79 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
80 			 OVL_FH_FLAG_PATH_UPPER)
81 
82 #if defined(__LITTLE_ENDIAN)
83 #define OVL_FH_FLAG_CPU_ENDIAN 0
84 #elif defined(__BIG_ENDIAN)
85 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
86 #else
87 #error Endianness not defined
88 #endif
89 
90 /* The type used to be returned by overlay exportfs for misaligned fid */
91 #define OVL_FILEID_V0	0xfb
92 /* The type returned by overlay exportfs for 32bit aligned fid */
93 #define OVL_FILEID_V1	0xf8
94 
95 /* On-disk format for "origin" file handle */
96 struct ovl_fb {
97 	u8 version;	/* 0 */
98 	u8 magic;	/* 0xfb */
99 	u8 len;		/* size of this header + size of fid */
100 	u8 flags;	/* OVL_FH_FLAG_* */
101 	u8 type;	/* fid_type of fid */
102 	uuid_t uuid;	/* uuid of filesystem */
103 	u32 fid[];	/* file identifier should be 32bit aligned in-memory */
104 } __packed;
105 
106 /* In-memory and on-wire format for overlay file handle */
107 struct ovl_fh {
108 	u8 padding[3];	/* make sure fb.fid is 32bit aligned */
109 	union {
110 		struct ovl_fb fb;
111 		u8 buf[0];
112 	};
113 } __packed;
114 
115 #define OVL_FH_WIRE_OFFSET	offsetof(struct ovl_fh, fb)
116 #define OVL_FH_LEN(fh)		(OVL_FH_WIRE_OFFSET + (fh)->fb.len)
117 #define OVL_FH_FID_OFFSET	(OVL_FH_WIRE_OFFSET + \
118 				 offsetof(struct ovl_fb, fid))
119 
120 extern const char *const ovl_xattr_table[][2];
ovl_xattr(struct ovl_fs * ofs,enum ovl_xattr ox)121 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
122 {
123 	return ovl_xattr_table[ox][ofs->config.userxattr];
124 }
125 
126 /*
127  * When changing ownership of an upper object map the intended ownership
128  * according to the upper layer's idmapping. When an upper mount idmaps files
129  * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
130  * this object will report it as being owned by id 1000 when calling stat via
131  * the upper mount.
132  * In order to change ownership of an object so stat reports id 1000 when
133  * called on an idmapped upper mount the value written to disk - i.e., the
134  * value stored in ia_*id - must 1001. The mount mapping helper will thus take
135  * care to map 1000 to 1001.
136  * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
137  */
ovl_do_notify_change(struct ovl_fs * ofs,struct dentry * upperdentry,struct iattr * attr)138 static inline int ovl_do_notify_change(struct ovl_fs *ofs,
139 				       struct dentry *upperdentry,
140 				       struct iattr *attr)
141 {
142 	struct user_namespace *upper_mnt_userns = ovl_upper_mnt_userns(ofs);
143 	struct user_namespace *fs_userns = i_user_ns(d_inode(upperdentry));
144 
145 	if (attr->ia_valid & ATTR_UID)
146 		attr->ia_uid = mapped_kuid_user(upper_mnt_userns,
147 						fs_userns, attr->ia_uid);
148 	if (attr->ia_valid & ATTR_GID)
149 		attr->ia_gid = mapped_kgid_user(upper_mnt_userns,
150 						fs_userns, attr->ia_gid);
151 
152 	return notify_change(upper_mnt_userns, upperdentry, attr, NULL);
153 }
154 
ovl_do_rmdir(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry)155 static inline int ovl_do_rmdir(struct ovl_fs *ofs,
156 			       struct inode *dir, struct dentry *dentry)
157 {
158 	int err = vfs_rmdir(ovl_upper_mnt_userns(ofs), dir, dentry);
159 
160 	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
161 	return err;
162 }
163 
ovl_do_unlink(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry)164 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
165 				struct dentry *dentry)
166 {
167 	int err = vfs_unlink(ovl_upper_mnt_userns(ofs), dir, dentry, NULL);
168 
169 	pr_debug("unlink(%pd2) = %i\n", dentry, err);
170 	return err;
171 }
172 
ovl_do_link(struct ovl_fs * ofs,struct dentry * old_dentry,struct inode * dir,struct dentry * new_dentry)173 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
174 			      struct inode *dir, struct dentry *new_dentry)
175 {
176 	int err = vfs_link(old_dentry, ovl_upper_mnt_userns(ofs), dir, new_dentry, NULL);
177 
178 	pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
179 	return err;
180 }
181 
ovl_do_create(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry,umode_t mode)182 static inline int ovl_do_create(struct ovl_fs *ofs,
183 				struct inode *dir, struct dentry *dentry,
184 				umode_t mode)
185 {
186 	int err = vfs_create(ovl_upper_mnt_userns(ofs), dir, dentry, mode, true);
187 
188 	pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
189 	return err;
190 }
191 
ovl_do_mkdir(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry,umode_t mode)192 static inline int ovl_do_mkdir(struct ovl_fs *ofs,
193 			       struct inode *dir, struct dentry *dentry,
194 			       umode_t mode)
195 {
196 	int err = vfs_mkdir(ovl_upper_mnt_userns(ofs), dir, dentry, mode);
197 	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
198 	return err;
199 }
200 
ovl_do_mknod(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)201 static inline int ovl_do_mknod(struct ovl_fs *ofs,
202 			       struct inode *dir, struct dentry *dentry,
203 			       umode_t mode, dev_t dev)
204 {
205 	int err = vfs_mknod(ovl_upper_mnt_userns(ofs), dir, dentry, mode, dev);
206 
207 	pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
208 	return err;
209 }
210 
ovl_do_symlink(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry,const char * oldname)211 static inline int ovl_do_symlink(struct ovl_fs *ofs,
212 				 struct inode *dir, struct dentry *dentry,
213 				 const char *oldname)
214 {
215 	int err = vfs_symlink(ovl_upper_mnt_userns(ofs), dir, dentry, oldname);
216 
217 	pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
218 	return err;
219 }
220 
ovl_do_getxattr(struct path * path,const char * name,void * value,size_t size)221 static inline ssize_t ovl_do_getxattr(struct path *path, const char *name,
222 				      void *value, size_t size)
223 {
224 	int err, len;
225 
226 	WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
227 
228 	err = vfs_getxattr(mnt_user_ns(path->mnt), path->dentry,
229 			       name, value, size);
230 	len = (value && err > 0) ? err : 0;
231 
232 	pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
233 		 path->dentry, name, min(len, 48), value, size, err);
234 	return err;
235 }
236 
ovl_getxattr_upper(struct ovl_fs * ofs,struct dentry * upperdentry,enum ovl_xattr ox,void * value,size_t size)237 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
238 					 struct dentry *upperdentry,
239 					 enum ovl_xattr ox, void *value,
240 					 size_t size)
241 {
242 	struct path upperpath = {
243 		.dentry = upperdentry,
244 		.mnt = ovl_upper_mnt(ofs),
245 	};
246 
247 	return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
248 }
249 
ovl_path_getxattr(struct ovl_fs * ofs,struct path * path,enum ovl_xattr ox,void * value,size_t size)250 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
251 					 struct path *path,
252 					 enum ovl_xattr ox, void *value,
253 					 size_t size)
254 {
255 	return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
256 }
257 
ovl_do_setxattr(struct ovl_fs * ofs,struct dentry * dentry,const char * name,const void * value,size_t size,int flags)258 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
259 				  const char *name, const void *value,
260 				  size_t size, int flags)
261 {
262 	int err = vfs_setxattr(ovl_upper_mnt_userns(ofs), dentry, name, value, size, flags);
263 
264 	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
265 		 dentry, name, min((int)size, 48), value, size, flags, err);
266 	return err;
267 }
268 
ovl_setxattr(struct ovl_fs * ofs,struct dentry * dentry,enum ovl_xattr ox,const void * value,size_t size)269 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
270 			       enum ovl_xattr ox, const void *value,
271 			       size_t size)
272 {
273 	return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
274 }
275 
ovl_do_removexattr(struct ovl_fs * ofs,struct dentry * dentry,const char * name)276 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
277 				     const char *name)
278 {
279 	int err = vfs_removexattr(ovl_upper_mnt_userns(ofs), dentry, name);
280 	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
281 	return err;
282 }
283 
ovl_removexattr(struct ovl_fs * ofs,struct dentry * dentry,enum ovl_xattr ox)284 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
285 				  enum ovl_xattr ox)
286 {
287 	return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
288 }
289 
ovl_do_rename(struct ovl_fs * ofs,struct inode * olddir,struct dentry * olddentry,struct inode * newdir,struct dentry * newdentry,unsigned int flags)290 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
291 				struct dentry *olddentry, struct inode *newdir,
292 				struct dentry *newdentry, unsigned int flags)
293 {
294 	int err;
295 	struct renamedata rd = {
296 		.old_mnt_userns	= ovl_upper_mnt_userns(ofs),
297 		.old_dir 	= olddir,
298 		.old_dentry 	= olddentry,
299 		.new_mnt_userns	= ovl_upper_mnt_userns(ofs),
300 		.new_dir 	= newdir,
301 		.new_dentry 	= newdentry,
302 		.flags 		= flags,
303 	};
304 
305 	pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
306 	err = vfs_rename(&rd);
307 	if (err) {
308 		pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
309 			 olddentry, newdentry, err);
310 	}
311 	return err;
312 }
313 
ovl_do_whiteout(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry)314 static inline int ovl_do_whiteout(struct ovl_fs *ofs,
315 				  struct inode *dir, struct dentry *dentry)
316 {
317 	int err = vfs_whiteout(ovl_upper_mnt_userns(ofs), dir, dentry);
318 	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
319 	return err;
320 }
321 
ovl_do_tmpfile(struct ovl_fs * ofs,struct dentry * dentry,umode_t mode)322 static inline struct dentry *ovl_do_tmpfile(struct ovl_fs *ofs,
323 					    struct dentry *dentry, umode_t mode)
324 {
325 	struct dentry *ret = vfs_tmpfile(ovl_upper_mnt_userns(ofs), dentry, mode, 0);
326 	int err = PTR_ERR_OR_ZERO(ret);
327 
328 	pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
329 	return ret;
330 }
331 
ovl_lookup_upper(struct ovl_fs * ofs,const char * name,struct dentry * base,int len)332 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
333 					      const char *name,
334 					      struct dentry *base, int len)
335 {
336 	return lookup_one(ovl_upper_mnt_userns(ofs), name, base, len);
337 }
338 
ovl_open_flags_need_copy_up(int flags)339 static inline bool ovl_open_flags_need_copy_up(int flags)
340 {
341 	if (!flags)
342 		return false;
343 
344 	return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
345 }
346 
ovl_allow_offline_changes(struct ovl_fs * ofs)347 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
348 {
349 	/*
350 	 * To avoid regressions in existing setups with overlay lower offline
351 	 * changes, we allow lower changes only if none of the new features
352 	 * are used.
353 	 */
354 	return (!ofs->config.index && !ofs->config.metacopy &&
355 		!ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
356 }
357 
358 
359 /* util.c */
360 int ovl_want_write(struct dentry *dentry);
361 void ovl_drop_write(struct dentry *dentry);
362 struct dentry *ovl_workdir(struct dentry *dentry);
363 const struct cred *ovl_override_creds(struct super_block *sb);
364 int ovl_can_decode_fh(struct super_block *sb);
365 struct dentry *ovl_indexdir(struct super_block *sb);
366 bool ovl_index_all(struct super_block *sb);
367 bool ovl_verify_lower(struct super_block *sb);
368 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
369 bool ovl_dentry_remote(struct dentry *dentry);
370 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
371 			     unsigned int mask);
372 bool ovl_dentry_weird(struct dentry *dentry);
373 enum ovl_path_type ovl_path_type(struct dentry *dentry);
374 void ovl_path_upper(struct dentry *dentry, struct path *path);
375 void ovl_path_lower(struct dentry *dentry, struct path *path);
376 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
377 void ovl_i_path_real(struct inode *inode, struct path *path);
378 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
379 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
380 struct dentry *ovl_dentry_upper(struct dentry *dentry);
381 struct dentry *ovl_dentry_lower(struct dentry *dentry);
382 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
383 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
384 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
385 struct dentry *ovl_dentry_real(struct dentry *dentry);
386 struct dentry *ovl_i_dentry_upper(struct inode *inode);
387 struct inode *ovl_inode_upper(struct inode *inode);
388 struct inode *ovl_inode_lower(struct inode *inode);
389 struct inode *ovl_inode_lowerdata(struct inode *inode);
390 struct inode *ovl_inode_real(struct inode *inode);
391 struct inode *ovl_inode_realdata(struct inode *inode);
392 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
393 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
394 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
395 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
396 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
397 bool ovl_dentry_is_opaque(struct dentry *dentry);
398 bool ovl_dentry_is_whiteout(struct dentry *dentry);
399 void ovl_dentry_set_opaque(struct dentry *dentry);
400 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
401 void ovl_dentry_set_upper_alias(struct dentry *dentry);
402 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
403 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
404 bool ovl_has_upperdata(struct inode *inode);
405 void ovl_set_upperdata(struct inode *inode);
406 bool ovl_redirect_dir(struct super_block *sb);
407 const char *ovl_dentry_get_redirect(struct dentry *dentry);
408 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
409 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
410 void ovl_dir_modified(struct dentry *dentry, bool impurity);
411 u64 ovl_dentry_version_get(struct dentry *dentry);
412 bool ovl_is_whiteout(struct dentry *dentry);
413 struct file *ovl_path_open(struct path *path, int flags);
414 int ovl_copy_up_start(struct dentry *dentry, int flags);
415 void ovl_copy_up_end(struct dentry *dentry);
416 bool ovl_already_copied_up(struct dentry *dentry, int flags);
417 bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, struct path *path,
418 			      enum ovl_xattr ox);
419 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path);
420 
ovl_check_origin_xattr(struct ovl_fs * ofs,struct dentry * upperdentry)421 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
422 					  struct dentry *upperdentry)
423 {
424 	struct path upperpath = {
425 		.dentry = upperdentry,
426 		.mnt = ovl_upper_mnt(ofs),
427 	};
428 	return ovl_path_check_origin_xattr(ofs, &upperpath);
429 }
430 
431 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
432 		       enum ovl_xattr ox, const void *value, size_t size,
433 		       int xerr);
434 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
435 bool ovl_inuse_trylock(struct dentry *dentry);
436 void ovl_inuse_unlock(struct dentry *dentry);
437 bool ovl_is_inuse(struct dentry *dentry);
438 bool ovl_need_index(struct dentry *dentry);
439 int ovl_nlink_start(struct dentry *dentry);
440 void ovl_nlink_end(struct dentry *dentry);
441 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
442 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct path *path);
443 bool ovl_is_metacopy_dentry(struct dentry *dentry);
444 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct path *path, int padding);
445 int ovl_sync_status(struct ovl_fs *ofs);
446 
ovl_set_flag(unsigned long flag,struct inode * inode)447 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
448 {
449 	set_bit(flag, &OVL_I(inode)->flags);
450 }
451 
ovl_clear_flag(unsigned long flag,struct inode * inode)452 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
453 {
454 	clear_bit(flag, &OVL_I(inode)->flags);
455 }
456 
ovl_test_flag(unsigned long flag,struct inode * inode)457 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
458 {
459 	return test_bit(flag, &OVL_I(inode)->flags);
460 }
461 
ovl_is_impuredir(struct super_block * sb,struct dentry * upperdentry)462 static inline bool ovl_is_impuredir(struct super_block *sb,
463 				    struct dentry *upperdentry)
464 {
465 	struct ovl_fs *ofs = OVL_FS(sb);
466 	struct path upperpath = {
467 		.dentry = upperdentry,
468 		.mnt = ovl_upper_mnt(ofs),
469 	};
470 
471 	return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
472 }
473 
474 /*
475  * With xino=auto, we do best effort to keep all inodes on same st_dev and
476  * d_ino consistent with st_ino.
477  * With xino=on, we do the same effort but we warn if we failed.
478  */
ovl_xino_warn(struct super_block * sb)479 static inline bool ovl_xino_warn(struct super_block *sb)
480 {
481 	return OVL_FS(sb)->config.xino == OVL_XINO_ON;
482 }
483 
484 /* All layers on same fs? */
ovl_same_fs(struct super_block * sb)485 static inline bool ovl_same_fs(struct super_block *sb)
486 {
487 	return OVL_FS(sb)->xino_mode == 0;
488 }
489 
490 /* All overlay inodes have same st_dev? */
ovl_same_dev(struct super_block * sb)491 static inline bool ovl_same_dev(struct super_block *sb)
492 {
493 	return OVL_FS(sb)->xino_mode >= 0;
494 }
495 
ovl_xino_bits(struct super_block * sb)496 static inline unsigned int ovl_xino_bits(struct super_block *sb)
497 {
498 	return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
499 }
500 
ovl_inode_lock(struct inode * inode)501 static inline void ovl_inode_lock(struct inode *inode)
502 {
503 	mutex_lock(&OVL_I(inode)->lock);
504 }
505 
ovl_inode_lock_interruptible(struct inode * inode)506 static inline int ovl_inode_lock_interruptible(struct inode *inode)
507 {
508 	return mutex_lock_interruptible(&OVL_I(inode)->lock);
509 }
510 
ovl_inode_unlock(struct inode * inode)511 static inline void ovl_inode_unlock(struct inode *inode)
512 {
513 	mutex_unlock(&OVL_I(inode)->lock);
514 }
515 
516 
517 /* namei.c */
518 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
519 
ovl_check_fh_len(struct ovl_fh * fh,int fh_len)520 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
521 {
522 	if (fh_len < sizeof(struct ovl_fh))
523 		return -EINVAL;
524 
525 	return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
526 }
527 
528 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
529 				  struct vfsmount *mnt, bool connected);
530 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
531 			struct dentry *upperdentry, struct ovl_path **stackp);
532 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
533 		      enum ovl_xattr ox, struct dentry *real, bool is_upper,
534 		      bool set);
535 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
536 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
537 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
538 		       struct qstr *name);
539 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
540 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
541 				struct dentry *origin, bool verify);
542 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
543 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
544 			  unsigned int flags);
545 bool ovl_lower_positive(struct dentry *dentry);
546 
ovl_verify_origin(struct ovl_fs * ofs,struct dentry * upper,struct dentry * origin,bool set)547 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
548 				    struct dentry *origin, bool set)
549 {
550 	return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
551 				 false, set);
552 }
553 
ovl_verify_upper(struct ovl_fs * ofs,struct dentry * index,struct dentry * upper,bool set)554 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
555 				   struct dentry *upper, bool set)
556 {
557 	return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
558 }
559 
560 /* readdir.c */
561 extern const struct file_operations ovl_dir_operations;
562 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
563 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
564 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
565 			   struct list_head *list);
566 void ovl_cache_free(struct list_head *list);
567 void ovl_dir_cache_free(struct inode *inode);
568 int ovl_check_d_type_supported(struct path *realpath);
569 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
570 			struct vfsmount *mnt, struct dentry *dentry, int level);
571 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
572 
573 /*
574  * Can we iterate real dir directly?
575  *
576  * Non-merge dir may contain whiteouts from a time it was a merge upper, before
577  * lower dir was removed under it and possibly before it was rotated from upper
578  * to lower layer.
579  */
ovl_dir_is_real(struct dentry * dir)580 static inline bool ovl_dir_is_real(struct dentry *dir)
581 {
582 	return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
583 }
584 
585 /* inode.c */
586 int ovl_set_nlink_upper(struct dentry *dentry);
587 int ovl_set_nlink_lower(struct dentry *dentry);
588 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
589 			   struct dentry *upperdentry,
590 			   unsigned int fallback);
591 int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
592 		struct iattr *attr);
593 int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
594 		struct kstat *stat, u32 request_mask, unsigned int flags);
595 int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode,
596 		   int mask);
597 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
598 		  const void *value, size_t size, int flags);
599 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
600 		  void *value, size_t size);
601 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
602 struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu);
603 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
604 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
605 
606 struct ovl_inode_params {
607 	struct inode *newinode;
608 	struct dentry *upperdentry;
609 	struct ovl_path *lowerpath;
610 	bool index;
611 	unsigned int numlower;
612 	char *redirect;
613 	struct dentry *lowerdata;
614 };
615 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
616 		    unsigned long ino, int fsid);
617 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
618 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
619 			       bool is_upper);
620 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
621 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
622 struct inode *ovl_get_inode(struct super_block *sb,
623 			    struct ovl_inode_params *oip);
624 void ovl_copyattr(struct inode *to);
625 
626 /* vfs inode flags copied from real to ovl inode */
627 #define OVL_COPY_I_FLAGS_MASK	(S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
628 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
629 #define OVL_PROT_I_FLAGS_MASK	(S_APPEND | S_IMMUTABLE)
630 
631 /*
632  * fileattr flags copied from lower to upper inode on copy up.
633  * We cannot copy up immutable/append-only flags, because that would prevent
634  * linking temp inode to upper dir, so we store them in xattr instead.
635  */
636 #define OVL_COPY_FS_FLAGS_MASK	(FS_SYNC_FL | FS_NOATIME_FL)
637 #define OVL_COPY_FSX_FLAGS_MASK	(FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
638 #define OVL_PROT_FS_FLAGS_MASK  (FS_APPEND_FL | FS_IMMUTABLE_FL)
639 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
640 
641 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
642 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
643 		      struct fileattr *fa);
644 
ovl_copyflags(struct inode * from,struct inode * to)645 static inline void ovl_copyflags(struct inode *from, struct inode *to)
646 {
647 	unsigned int mask = OVL_COPY_I_FLAGS_MASK;
648 
649 	inode_set_flags(to, from->i_flags & mask, mask);
650 }
651 
652 /* dir.c */
653 extern const struct inode_operations ovl_dir_inode_operations;
654 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
655 			     struct dentry *dentry);
656 struct ovl_cattr {
657 	dev_t rdev;
658 	umode_t mode;
659 	const char *link;
660 	struct dentry *hardlink;
661 };
662 
663 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
664 
665 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
666 		   struct dentry **newdentry, umode_t mode);
667 struct dentry *ovl_create_real(struct ovl_fs *ofs,
668 			       struct inode *dir, struct dentry *newdentry,
669 			       struct ovl_cattr *attr);
670 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
671 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
672 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
673 			       struct ovl_cattr *attr);
674 
675 /* file.c */
676 extern const struct file_operations ovl_file_operations;
677 int __init ovl_aio_request_cache_init(void);
678 void ovl_aio_request_cache_destroy(void);
679 int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa);
680 int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa);
681 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
682 int ovl_fileattr_set(struct user_namespace *mnt_userns,
683 		     struct dentry *dentry, struct fileattr *fa);
684 
685 /* copy_up.c */
686 int ovl_copy_up(struct dentry *dentry);
687 int ovl_copy_up_with_data(struct dentry *dentry);
688 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
689 int ovl_copy_xattr(struct super_block *sb, struct path *path, struct dentry *new);
690 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
691 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
692 				  bool is_upper);
693 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
694 		   struct dentry *upper);
695 
696 /* export.c */
697 extern const struct export_operations ovl_export_operations;
698