summaryrefslogtreecommitdiffstats
path: root/fs/overlayfs/overlayfs.h
blob: d26efed9f80af753767fbac1b28f38edacc491ea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/*
 *
 * Copyright (C) 2011 Novell Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/uuid.h>
#include <linux/fs.h>
#include "ovl_entry.h"

enum ovl_path_type {
	__OVL_PATH_UPPER	= (1 << 0),
	__OVL_PATH_MERGE	= (1 << 1),
	__OVL_PATH_ORIGIN	= (1 << 2),
};

#define OVL_TYPE_UPPER(type)	((type) & __OVL_PATH_UPPER)
#define OVL_TYPE_MERGE(type)	((type) & __OVL_PATH_MERGE)
#define OVL_TYPE_ORIGIN(type)	((type) & __OVL_PATH_ORIGIN)

#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
#define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
#define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
#define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
#define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
#define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"

enum ovl_inode_flag {
	/* Pure upper dir that may contain non pure upper entries */
	OVL_IMPURE,
	/* Non-merge dir that may contain whiteout entries */
	OVL_WHITEOUTS,
	OVL_INDEX,
	OVL_UPPERDATA,
	/* Inode number will remain constant over copy up. */
	OVL_CONST_INO,
};

enum ovl_entry_flag {
	OVL_E_UPPER_ALIAS,
	OVL_E_OPAQUE,
	OVL_E_CONNECTED,
};

/*
 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
 * where:
 * origin.fh	- exported file handle of the lower file
 * origin.uuid	- uuid of the lower filesystem
 */
#define OVL_FH_VERSION	0
#define OVL_FH_MAGIC	0xfb

/* CPU byte order required for fid decoding:  */
#define OVL_FH_FLAG_BIG_ENDIAN	(1 << 0)
#define OVL_FH_FLAG_ANY_ENDIAN	(1 << 1)
/* Is the real inode encoded in fid an upper inode? */
#define OVL_FH_FLAG_PATH_UPPER	(1 << 2)

#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
			 OVL_FH_FLAG_PATH_UPPER)

#if defined(__LITTLE_ENDIAN)
#define OVL_FH_FLAG_CPU_ENDIAN 0
#elif defined(__BIG_ENDIAN)
#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
#else
#error Endianness not defined
#endif

/* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
#define OVL_FILEID	0xfb

/* On-disk and in-memeory format for redirect by file handle */
struct ovl_fh {
	u8 version;	/* 0 */
	u8 magic;	/* 0xfb */
	u8 len;		/* size of this header + size of fid */
	u8 flags;	/* OVL_FH_FLAG_* */
	u8 type;	/* fid_type of fid */
	uuid_t uuid;	/* uuid of filesystem */
	u8 fid[0];	/* file identifier */
} __packed;

static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_rmdir(dir, dentry);

	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
	return err;
}

static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_unlink(dir, dentry, NULL);

	pr_debug("unlink(%pd2) = %i\n", dentry, err);
	return err;
}

static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
			      struct dentry *new_dentry)
{
	int err = vfs_link(old_dentry, dir, new_dentry, NULL);

	pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
	return err;
}

static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
				umode_t mode)
{
	int err = vfs_create(dir, dentry, mode, true);

	pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
	return err;
}

static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
			       umode_t mode)
{
	int err = vfs_mkdir(dir, dentry, mode);
	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
	return err;
}

static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
			       umode_t mode, dev_t dev)
{
	int err = vfs_mknod(dir, dentry, mode, dev);

	pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
	return err;
}

static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
				 const char *oldname)
{
	int err = vfs_symlink(dir, dentry, oldname);

	pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
	return err;
}

static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
				  const void *value, size_t size, int flags)
{
	int err = vfs_setxattr(dentry, name, value, size, flags);
	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
		 dentry, name, min((int)size, 48), value, size, flags, err);
	return err;
}

static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
{
	int err = vfs_removexattr(dentry, name);
	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
	return err;
}

static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
				struct inode *newdir, struct dentry *newdentry,
				unsigned int flags)
{
	int err;

	pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
	err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
	if (err) {
		pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
			 olddentry, newdentry, err);
	}
	return err;
}

static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
{
	int err = vfs_whiteout(dir, dentry);
	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
	return err;
}

static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
{
	struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
	int err = PTR_ERR_OR_ZERO(ret);

	pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
	return ret;
}

static inline bool ovl_open_flags_need_copy_up(int flags)
{
	if (!flags)
		return false;

	return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
}

/* util.c */
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
struct dentry *ovl_workdir(struct dentry *dentry);
const struct cred *ovl_override_creds(struct super_block *sb);
struct super_block *ovl_same_sb(struct super_block *sb);
int ovl_can_decode_fh(struct super_block *sb);
struct dentry *ovl_indexdir(struct super_block *sb);
bool ovl_index_all(struct super_block *sb);
bool ovl_verify_lower(struct super_block *sb);
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
bool ovl_dentry_remote(struct dentry *dentry);
bool ovl_dentry_weird(struct dentry *dentry);
enum ovl_path_type ovl_path_type(struct dentry *dentry);
void ovl_path_upper(struct dentry *dentry, struct path *path);
void ovl_path_lower(struct dentry *dentry, struct path *path);
void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
struct dentry *ovl_i_dentry_upper(struct inode *inode);
struct inode *ovl_inode_upper(struct inode *inode);
struct inode *ovl_inode_lower(struct inode *inode);
struct inode *ovl_inode_lowerdata(struct inode *inode);
struct inode *ovl_inode_real(struct inode *inode);
struct inode *ovl_inode_realdata(struct inode *inode);
struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
bool ovl_dentry_has_upper_alias(struct dentry *dentry);
void ovl_dentry_set_upper_alias(struct dentry *dentry);
bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
bool ovl_has_upperdata(struct inode *inode);
void ovl_set_upperdata(struct inode *inode);
bool ovl_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
		    struct dentry *lowerdentry, struct dentry *lowerdata);
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
void ovl_dir_modified(struct dentry *dentry, bool impurity);
u64 ovl_dentry_version_get(struct dentry *dentry);
bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
int ovl_copy_up_start(struct dentry *dentry, int flags);
void ovl_copy_up_end(struct dentry *dentry);
bool ovl_already_copied_up(struct dentry *dentry, int flags);
bool ovl_check_origin_xattr(struct dentry *dentry);
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
		       const char *name, const void *value, size_t size,
		       int xerr);
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
void ovl_set_flag(unsigned long flag, struct inode *inode);
void ovl_clear_flag(unsigned long flag, struct inode *inode);
bool ovl_test_flag(unsigned long flag, struct inode *inode);
bool ovl_inuse_trylock(struct dentry *dentry);
void ovl_inuse_unlock(struct dentry *dentry);
bool ovl_need_index(struct dentry *dentry);
int ovl_nlink_start(struct dentry *dentry);
void ovl_nlink_end(struct dentry *dentry);
int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
int ovl_check_metacopy_xattr(struct dentry *dentry);
bool ovl_is_metacopy_dentry(struct dentry *dentry);
char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
		     size_t padding);

static inline bool ovl_is_impuredir(struct dentry *dentry)
{
	return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
}

static inline unsigned int ovl_xino_bits(struct super_block *sb)
{
	struct ovl_fs *ofs = sb->s_fs_info;

	return ofs->xino_bits;
}

static inline int ovl_inode_lock(struct inode *inode)
{
	return mutex_lock_interruptible(&OVL_I(inode)->lock);
}

static inline void ovl_inode_unlock(struct inode *inode)
{
	mutex_unlock(&OVL_I(inode)->lock);
}


/* namei.c */
int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
				  bool connected);
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
			struct dentry *upperdentry, struct ovl_path **stackp);
int ovl_verify_set_fh(struct dentry *dentry, const char *name,
		      struct dentry *real, bool is_upper, bool set);
struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
int ovl_get_index_name(struct dentry *origin, struct qstr *name);
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
				struct dentry *origin, bool verify);
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
			  unsigned int flags);
bool ovl_lower_positive(struct dentry *dentry);

static inline int ovl_verify_origin(struct dentry *upper,
				    struct dentry *origin, bool set)
{
	return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
}

static inline int ovl_verify_upper(struct dentry *index,
				    struct dentry *upper, bool set)
{
	return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
}

/* readdir.c */
extern const struct file_operations ovl_dir_operations;
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
void ovl_cache_free(struct list_head *list);
void ovl_dir_cache_free(struct inode *inode);
int ovl_check_d_type_supported(struct path *realpath);
void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
			 struct dentry *dentry, int level);
int ovl_indexdir_cleanup(struct ovl_fs *ofs);

/* inode.c */
int ovl_set_nlink_upper(struct dentry *dentry);
int ovl_set_nlink_lower(struct dentry *dentry);
unsigned int ovl_get_nlink(struct dentry *lowerdentry,
			   struct dentry *upperdentry,
			   unsigned int fallback);
int ovl_setattr(struct dentry *dentry, struct iattr *attr);
int ovl_getattr(const struct path *path, struct kstat *stat,
		u32 request_mask, unsigned int flags);
int ovl_permission(struct inode *inode, int mask);
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
		  const void *value, size_t size, int flags);
int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
		  void *value, size_t size);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
struct posix_acl *ovl_get_acl(struct inode *inode, int type);
int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
bool ovl_is_private_xattr(const char *name);

struct ovl_inode_params {
	struct inode *newinode;
	struct dentry *upperdentry;
	struct ovl_path *lowerpath;
	struct dentry *index;
	unsigned int numlower;
	char *redirect;
	struct dentry *lowerdata;
};
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
			       bool is_upper);
struct inode *ovl_get_inode(struct super_block *sb,
			    struct ovl_inode_params *oip);
static inline void ovl_copyattr(struct inode *from, struct inode *to)
{
	to->i_uid = from->i_uid;
	to->i_gid = from->i_gid;
	to->i_mode = from->i_mode;
	to->i_atime = from->i_atime;
	to->i_mtime = from->i_mtime;
	to->i_ctime = from->i_ctime;
	i_size_write(to, i_size_read(from));
}

static inline void ovl_copyflags(struct inode *from, struct inode *to)
{
	unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;

	inode_set_flags(to, from->i_flags & mask, mask);
}

/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
			     struct dentry *dentry);
struct ovl_cattr {
	dev_t rdev;
	umode_t mode;
	const char *link;
	struct dentry *hardlink;
};

#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })

struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
			       struct ovl_cattr *attr);
int ovl_cleanup(struct inode *dir, struct dentry *dentry);
struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);

/* file.c */
extern const struct file_operations ovl_file_operations;

/* copy_up.c */
int ovl_copy_up(struct dentry *dentry);
int ovl_copy_up_with_data(struct dentry *dentry);
int ovl_copy_up_flags(struct dentry *dentry, int flags);
int ovl_maybe_copy_up(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
		   struct dentry *upper);

/* export.c */
extern const struct export_operations ovl_export_operations;