overlayfs.h

  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/fsverity.h>
 11#include <linux/namei.h>
 12#include <linux/posix_acl.h>
 13#include <linux/posix_acl_xattr.h>
 14#include "ovl_entry.h"
 15
 16#undef pr_fmt
 17#define pr_fmt(fmt) "overlayfs: " fmt
 18
 19enum ovl_path_type {
 20	__OVL_PATH_UPPER	= (1 << 0),
 21	__OVL_PATH_MERGE	= (1 << 1),
 22	__OVL_PATH_ORIGIN	= (1 << 2),
 23};
 24
 25#define OVL_TYPE_UPPER(type)	((type) & __OVL_PATH_UPPER)
 26#define OVL_TYPE_MERGE(type)	((type) & __OVL_PATH_MERGE)
 27#define OVL_TYPE_ORIGIN(type)	((type) & __OVL_PATH_ORIGIN)
 28
 29#define OVL_XATTR_NAMESPACE "overlay."
 30#define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
 31#define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1)
 32#define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
 33#define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1)
 34
 35#define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE
 36#define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1)
 37#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX
 38#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1)
 39#define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX
 40#define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1)
 41
 42enum ovl_xattr {
 43	OVL_XATTR_OPAQUE,
 44	OVL_XATTR_REDIRECT,
 45	OVL_XATTR_ORIGIN,
 46	OVL_XATTR_IMPURE,
 47	OVL_XATTR_NLINK,
 48	OVL_XATTR_UPPER,
 49	OVL_XATTR_UUID,
 50	OVL_XATTR_METACOPY,
 51	OVL_XATTR_PROTATTR,
 52	OVL_XATTR_XWHITEOUT,
 53};
 54
 55enum ovl_inode_flag {
 56	/* Pure upper dir that may contain non pure upper entries */
 57	OVL_IMPURE,
 58	/* Non-merge dir that may contain whiteout entries */
 59	OVL_WHITEOUTS,
 60	OVL_INDEX,
 61	OVL_UPPERDATA,
 62	/* Inode number will remain constant over copy up. */
 63	OVL_CONST_INO,
 64	OVL_HAS_DIGEST,
 65	OVL_VERIFIED_DIGEST,
 66};
 67
 68enum ovl_entry_flag {
 69	OVL_E_UPPER_ALIAS,
 70	OVL_E_OPAQUE,
 71	OVL_E_CONNECTED,
 72	/* Lower stack may contain xwhiteout entries */
 73	OVL_E_XWHITEOUTS,
 74};
 75
 76enum {
 77	OVL_REDIRECT_OFF,	/* "off" mode is never used. In effect	*/
 78	OVL_REDIRECT_FOLLOW,	/* ...it translates to either "follow"	*/
 79	OVL_REDIRECT_NOFOLLOW,	/* ...or "nofollow".			*/
 80	OVL_REDIRECT_ON,
 81};
 82
 83enum {
 84	OVL_UUID_OFF,
 85	OVL_UUID_NULL,
 86	OVL_UUID_AUTO,
 87	OVL_UUID_ON,
 88};
 89
 90enum {
 91	OVL_XINO_OFF,
 92	OVL_XINO_AUTO,
 93	OVL_XINO_ON,
 94};
 95
 96enum {
 97	OVL_VERITY_OFF,
 98	OVL_VERITY_ON,
 99	OVL_VERITY_REQUIRE,
100};
101
102enum {
103	OVL_FSYNC_VOLATILE,
104	OVL_FSYNC_AUTO,
105	OVL_FSYNC_STRICT,
106};
107
108/*
109 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
110 * where:
111 * origin.fh	- exported file handle of the lower file
112 * origin.uuid	- uuid of the lower filesystem
113 */
114#define OVL_FH_VERSION	0
115#define OVL_FH_MAGIC	0xfb
116
117/* CPU byte order required for fid decoding:  */
118#define OVL_FH_FLAG_BIG_ENDIAN	(1 << 0)
119#define OVL_FH_FLAG_ANY_ENDIAN	(1 << 1)
120/* Is the real inode encoded in fid an upper inode? */
121#define OVL_FH_FLAG_PATH_UPPER	(1 << 2)
122
123#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
124			 OVL_FH_FLAG_PATH_UPPER)
125
126#if defined(__LITTLE_ENDIAN)
127#define OVL_FH_FLAG_CPU_ENDIAN 0
128#elif defined(__BIG_ENDIAN)
129#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
130#else
131#error Endianness not defined
132#endif
133
134/* The type used to be returned by overlay exportfs for misaligned fid */
135#define OVL_FILEID_V0	0xfb
136/* The type returned by overlay exportfs for 32bit aligned fid */
137#define OVL_FILEID_V1	0xf8
138
139/* On-disk format for "origin" file handle */
140struct ovl_fb {
141	u8 version;	/* 0 */
142	u8 magic;	/* 0xfb */
143	u8 len;		/* size of this header + size of fid */
144	u8 flags;	/* OVL_FH_FLAG_* */
145	u8 type;	/* fid_type of fid */
146	uuid_t uuid;	/* uuid of filesystem */
147	u32 fid[];	/* file identifier should be 32bit aligned in-memory */
148} __packed;
149
150/* In-memory and on-wire format for overlay file handle */
151struct ovl_fh {
152	u8 padding[3];	/* make sure fb.fid is 32bit aligned */
153	union {
154		struct ovl_fb fb;
155		DECLARE_FLEX_ARRAY(u8, buf);
156	};
157} __packed;
158
159#define OVL_FH_WIRE_OFFSET	offsetof(struct ovl_fh, fb)
160#define OVL_FH_LEN(fh)		(OVL_FH_WIRE_OFFSET + (fh)->fb.len)
161#define OVL_FH_FID_OFFSET	(OVL_FH_WIRE_OFFSET + \
162				 offsetof(struct ovl_fb, fid))
163
164/* On-disk format for "metacopy" xattr (if non-zero size) */
165struct ovl_metacopy {
166	u8 version;	/* 0 */
167	u8 len;         /* size of this header + used digest bytes */
168	u8 flags;
169	u8 digest_algo;	/* FS_VERITY_HASH_ALG_* constant, 0 for no digest */
170	u8 digest[FS_VERITY_MAX_DIGEST_SIZE];  /* Only the used part on disk */
171} __packed;
172
173#define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy))
174#define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE)
175#define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE }
176
177static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy)
178{
179	if (metacopy->len < OVL_METACOPY_MIN_SIZE)
180		return 0;
181	return (int)metacopy->len - OVL_METACOPY_MIN_SIZE;
182}
183
184/* No atime modification on underlying */
185#define OVL_OPEN_FLAGS (O_NOATIME)
186
187extern const char *const ovl_xattr_table[][2];
188static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
189{
190	return ovl_xattr_table[ox][ofs->config.userxattr];
191}
192
193/*
194 * When changing ownership of an upper object map the intended ownership
195 * according to the upper layer's idmapping. When an upper mount idmaps files
196 * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
197 * this object will report it as being owned by id 1000 when calling stat via
198 * the upper mount.
199 * In order to change ownership of an object so stat reports id 1000 when
200 * called on an idmapped upper mount the value written to disk - i.e., the
201 * value stored in ia_*id - must 1001. The mount mapping helper will thus take
202 * care to map 1000 to 1001.
203 * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
204 */
205static inline int ovl_do_notify_change(struct ovl_fs *ofs,
206				       struct dentry *upperdentry,
207				       struct iattr *attr)
208{
209	return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
210}
211
212static inline int ovl_do_rmdir(struct ovl_fs *ofs,
213			       struct inode *dir, struct dentry *dentry)
214{
215	int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
216
217	pr_debug("rmdir(%pd2) = %i\n", dentry, err);
218	return err;
219}
220
221static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
222				struct dentry *dentry)
223{
224	int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
225
226	pr_debug("unlink(%pd2) = %i\n", dentry, err);
227	return err;
228}
229
230static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
231			      struct inode *dir, struct dentry *new_dentry)
232{
233	int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir,
234			   new_dentry, NULL);
235
236	pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
237	return err;
238}
239
240static inline int ovl_do_create(struct ovl_fs *ofs,
241				struct inode *dir, struct dentry *dentry,
242				umode_t mode)
243{
244	int err = vfs_create(ovl_upper_mnt_idmap(ofs), dentry, mode, NULL);
245
246	pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
247	return err;
248}
249
250static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs,
251					  struct inode *dir,
252					  struct dentry *dentry,
253					  umode_t mode)
254{
255	struct dentry *ret;
256
257	ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, NULL);
258	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(ret));
259	return ret;
260}
261
262static inline int ovl_do_mknod(struct ovl_fs *ofs,
263			       struct inode *dir, struct dentry *dentry,
264			       umode_t mode, dev_t dev)
265{
266	int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev, NULL);
267
268	pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
269	return err;
270}
271
272static inline int ovl_do_symlink(struct ovl_fs *ofs,
273				 struct inode *dir, struct dentry *dentry,
274				 const char *oldname)
275{
276	int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname, NULL);
277
278	pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
279	return err;
280}
281
282static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
283				      void *value, size_t size)
284{
285	int err, len;
286
287	WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
288
289	err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry,
290			       name, value, size);
291	len = (value && err > 0) ? err : 0;
292
293	pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
294		 path->dentry, name, min(len, 48), value, size, err);
295	return err;
296}
297
298static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
299					 struct dentry *upperdentry,
300					 enum ovl_xattr ox, void *value,
301					 size_t size)
302{
303	struct path upperpath = {
304		.dentry = upperdentry,
305		.mnt = ovl_upper_mnt(ofs),
306	};
307
308	return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
309}
310
311static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
312					 const struct path *path,
313					 enum ovl_xattr ox, void *value,
314					 size_t size)
315{
316	return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
317}
318
319static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
320				  const char *name, const void *value,
321				  size_t size, int flags)
322{
323	int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
324			       value, size, flags);
325
326	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
327		 dentry, name, min((int)size, 48), value, size, flags, err);
328	return err;
329}
330
331static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
332			       enum ovl_xattr ox, const void *value,
333			       size_t size)
334{
335	return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
336}
337
338static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
339				     const char *name)
340{
341	int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
342	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
343	return err;
344}
345
346static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
347				  enum ovl_xattr ox)
348{
349	return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
350}
351
352static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
353				 const char *acl_name, struct posix_acl *acl)
354{
355	return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl);
356}
357
358static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
359				    const char *acl_name)
360{
361	return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name);
362}
363
364static inline int ovl_do_rename_rd(struct renamedata *rd)
365{
366	int err;
367
368	pr_debug("rename(%pd2, %pd2, 0x%x)\n", rd->old_dentry, rd->new_dentry,
369		 rd->flags);
370	err = vfs_rename(rd);
371	if (err) {
372		pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
373			 rd->old_dentry, rd->new_dentry, err);
374	}
375	return err;
376}
377
378static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir,
379				struct dentry *olddentry, struct dentry *newdir,
380				struct dentry *newdentry, unsigned int flags)
381{
382	struct renamedata rd = {
383		.mnt_idmap	= ovl_upper_mnt_idmap(ofs),
384		.old_parent	= olddir,
385		.old_dentry	= olddentry,
386		.new_parent	= newdir,
387		.new_dentry	= newdentry,
388		.flags		= flags,
389	};
390
391	return ovl_do_rename_rd(&rd);
392}
393
394static inline int ovl_do_whiteout(struct ovl_fs *ofs,
395				  struct inode *dir, struct dentry *dentry)
396{
397	int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry);
398	pr_debug("whiteout(%pd2) = %i\n", dentry, err);
399	return err;
400}
401
402static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
403					  struct dentry *dentry, umode_t mode)
404{
405	struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
406	struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path,
407						mode, O_LARGEFILE | O_WRONLY,
408						current_cred());
409	int err = PTR_ERR_OR_ZERO(file);
410
411	pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
412	return file;
413}
414
415static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
416					      const char *name,
417					      struct dentry *base, int len)
418{
419	return lookup_one(ovl_upper_mnt_idmap(ofs), &QSTR_LEN(name, len), base);
420}
421
422static inline struct dentry *ovl_lookup_upper_unlocked(struct ovl_fs *ofs,
423						       const char *name,
424						       struct dentry *base,
425						       int len)
426{
427	return lookup_one_unlocked(ovl_upper_mnt_idmap(ofs),
428				   &QSTR_LEN(name, len), base);
429}
430
431static inline struct dentry *ovl_start_creating_upper(struct ovl_fs *ofs,
432						      struct dentry *parent,
433						      struct qstr *name)
434{
435	return start_creating(ovl_upper_mnt_idmap(ofs),
436			      parent, name);
437}
438
439static inline struct dentry *ovl_start_removing_upper(struct ovl_fs *ofs,
440						      struct dentry *parent,
441						      struct qstr *name)
442{
443	return start_removing(ovl_upper_mnt_idmap(ofs),
444			      parent, name);
445}
446
447static inline bool ovl_open_flags_need_copy_up(int flags)
448{
449	if (!flags)
450		return false;
451
452	return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
453}
454
455/* util.c */
456int ovl_get_write_access(struct dentry *dentry);
457void ovl_put_write_access(struct dentry *dentry);
458void ovl_start_write(struct dentry *dentry);
459void ovl_end_write(struct dentry *dentry);
460int ovl_want_write(struct dentry *dentry);
461void ovl_drop_write(struct dentry *dentry);
462struct dentry *ovl_workdir(struct dentry *dentry);
463const struct cred *ovl_override_creds(struct super_block *sb);
464
465EXTEND_CLASS(override_creds, _ovl, ovl_override_creds(sb), struct super_block *sb)
466
467#define with_ovl_creds(sb) \
468	scoped_class(override_creds_ovl, __UNIQUE_ID(label), sb)
469
470static inline const struct cred *ovl_creds(struct super_block *sb)
471{
472	return OVL_FS(sb)->creator_cred;
473}
474
475int ovl_can_decode_fh(struct super_block *sb);
476struct dentry *ovl_indexdir(struct super_block *sb);
477bool ovl_index_all(struct super_block *sb);
478bool ovl_verify_lower(struct super_block *sb);
479struct ovl_path *ovl_stack_alloc(unsigned int n);
480void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
481void ovl_stack_put(struct ovl_path *stack, unsigned int n);
482void ovl_stack_free(struct ovl_path *stack, unsigned int n);
483struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
484void ovl_free_entry(struct ovl_entry *oe);
485bool ovl_dentry_remote(struct dentry *dentry);
486void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
487void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
488			   struct ovl_entry *oe);
489void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
490			   struct ovl_entry *oe, unsigned int mask);
491bool ovl_dentry_weird(struct dentry *dentry);
492
493static inline bool ovl_dentry_casefolded(struct dentry *dentry)
494{
495	return sb_has_encoding(dentry->d_sb) && IS_CASEFOLDED(d_inode(dentry));
496}
497
498enum ovl_path_type ovl_path_type(struct dentry *dentry);
499void ovl_path_upper(struct dentry *dentry, struct path *path);
500void ovl_path_lower(struct dentry *dentry, struct path *path);
501void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
502struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
503enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
504enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
505struct dentry *ovl_dentry_upper(struct dentry *dentry);
506struct dentry *ovl_dentry_lower(struct dentry *dentry);
507struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
508int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
509const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
510const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
511struct dentry *ovl_dentry_real(struct dentry *dentry);
512struct dentry *ovl_i_dentry_upper(struct inode *inode);
513struct inode *ovl_inode_upper(struct inode *inode);
514struct inode *ovl_inode_lower(struct inode *inode);
515struct inode *ovl_inode_lowerdata(struct inode *inode);
516struct inode *ovl_inode_real(struct inode *inode);
517struct inode *ovl_inode_realdata(struct inode *inode);
518const char *ovl_lowerdata_redirect(struct inode *inode);
519struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
520void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
521void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
522void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
523bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
524bool ovl_dentry_is_opaque(struct dentry *dentry);
525bool ovl_dentry_is_whiteout(struct dentry *dentry);
526void ovl_dentry_set_opaque(struct dentry *dentry);
527bool ovl_dentry_has_xwhiteouts(struct dentry *dentry);
528void ovl_dentry_set_xwhiteouts(struct dentry *dentry);
529void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs,
530			      const struct ovl_layer *layer);
531bool ovl_dentry_has_upper_alias(struct dentry *dentry);
532void ovl_dentry_set_upper_alias(struct dentry *dentry);
533bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
534bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
535bool ovl_has_upperdata(struct inode *inode);
536void ovl_set_upperdata(struct inode *inode);
537const char *ovl_dentry_get_redirect(struct dentry *dentry);
538void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
539void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
540void ovl_dir_modified(struct dentry *dentry, bool impurity);
541u64 ovl_inode_version_get(struct inode *inode);
542bool ovl_is_whiteout(struct dentry *dentry);
543bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
544struct file *ovl_path_open(const struct path *path, int flags);
545int ovl_copy_up_start(struct dentry *dentry, int flags);
546void ovl_copy_up_end(struct dentry *dentry);
547bool ovl_already_copied_up(struct dentry *dentry, int flags);
548char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path,
549			   enum ovl_xattr ox);
550bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
551bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
552bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
553			 const struct path *upperpath);
554
555static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
556					 struct dentry *upperdentry)
557{
558	struct path upperpath = {
559		.dentry = upperdentry,
560		.mnt = ovl_upper_mnt(ofs),
561	};
562	return ovl_path_is_whiteout(ofs, &upperpath);
563}
564
565static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
566					  struct dentry *upperdentry)
567{
568	struct path upperpath = {
569		.dentry = upperdentry,
570		.mnt = ovl_upper_mnt(ofs),
571	};
572	return ovl_path_check_origin_xattr(ofs, &upperpath);
573}
574
575int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
576		       enum ovl_xattr ox, const void *value, size_t size,
577		       int xerr);
578int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
579bool ovl_inuse_trylock(struct dentry *dentry);
580void ovl_inuse_unlock(struct dentry *dentry);
581bool ovl_is_inuse(struct dentry *dentry);
582bool ovl_need_index(struct dentry *dentry);
583int ovl_nlink_start(struct dentry *dentry);
584void ovl_nlink_end(struct dentry *dentry);
585int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *work,
586			    struct dentry *upperdir, struct dentry *upper);
587int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path,
588			     struct ovl_metacopy *data);
589int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d,
590			   struct ovl_metacopy *metacopy);
591bool ovl_is_metacopy_dentry(struct dentry *dentry);
592char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
593int ovl_ensure_verity_loaded(const struct path *path);
594int ovl_validate_verity(struct ovl_fs *ofs,
595			const struct path *metapath,
596			const struct path *datapath);
597int ovl_get_verity_digest(struct ovl_fs *ofs, const struct path *src,
598			  struct ovl_metacopy *metacopy);
599int ovl_sync_status(struct ovl_fs *ofs);
600
601static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
602{
603	set_bit(flag, &OVL_I(inode)->flags);
604}
605
606static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
607{
608	clear_bit(flag, &OVL_I(inode)->flags);
609}
610
611static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
612{
613	return test_bit(flag, &OVL_I(inode)->flags);
614}
615
616static inline bool ovl_is_impuredir(struct super_block *sb,
617				    struct dentry *upperdentry)
618{
619	struct ovl_fs *ofs = OVL_FS(sb);
620	struct path upperpath = {
621		.dentry = upperdentry,
622		.mnt = ovl_upper_mnt(ofs),
623	};
624
625	return ovl_get_dir_xattr_val(ofs, &upperpath, OVL_XATTR_IMPURE) == 'y';
626}
627
628static inline char ovl_get_opaquedir_val(struct ovl_fs *ofs,
629					 const struct path *path)
630{
631	return ovl_get_dir_xattr_val(ofs, path, OVL_XATTR_OPAQUE);
632}
633
634static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
635{
636	return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
637}
638
639static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
640{
641	return ofs->config.redirect_mode == OVL_REDIRECT_ON;
642}
643
644static inline bool ovl_origin_uuid(struct ovl_fs *ofs)
645{
646	return ofs->config.uuid != OVL_UUID_OFF;
647}
648
649static inline bool ovl_has_fsid(struct ovl_fs *ofs)
650{
651	return ofs->config.uuid == OVL_UUID_ON ||
652	       ofs->config.uuid == OVL_UUID_AUTO;
653}
654
655/*
656 * With xino=auto, we do best effort to keep all inodes on same st_dev and
657 * d_ino consistent with st_ino.
658 * With xino=on, we do the same effort but we warn if we failed.
659 */
660static inline bool ovl_xino_warn(struct ovl_fs *ofs)
661{
662	return ofs->config.xino == OVL_XINO_ON;
663}
664
665static inline bool ovl_should_sync(struct ovl_fs *ofs)
666{
667	return ofs->config.fsync_mode != OVL_FSYNC_VOLATILE;
668}
669
670static inline bool ovl_should_sync_metadata(struct ovl_fs *ofs)
671{
672	return ofs->config.fsync_mode == OVL_FSYNC_STRICT;
673}
674
675static inline bool ovl_is_volatile(struct ovl_config *config)
676{
677	return config->fsync_mode == OVL_FSYNC_VOLATILE;
678}
679
680/*
681 * To avoid regressions in existing setups with overlay lower offline changes,
682 * we allow lower changes only if none of the new features are used.
683 */
684static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
685{
686	return (!ofs->config.index && !ofs->config.metacopy &&
687		!ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
688}
689
690/* All layers on same fs? */
691static inline bool ovl_same_fs(struct ovl_fs *ofs)
692{
693	return ofs->xino_mode == 0;
694}
695
696/* All overlay inodes have same st_dev? */
697static inline bool ovl_same_dev(struct ovl_fs *ofs)
698{
699	return ofs->xino_mode >= 0;
700}
701
702static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
703{
704	return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
705}
706
707static inline void ovl_inode_lock(struct inode *inode)
708{
709	mutex_lock(&OVL_I(inode)->lock);
710}
711
712static inline int ovl_inode_lock_interruptible(struct inode *inode)
713{
714	return mutex_lock_interruptible(&OVL_I(inode)->lock);
715}
716
717static inline void ovl_inode_unlock(struct inode *inode)
718{
719	mutex_unlock(&OVL_I(inode)->lock);
720}
721
722
723/* namei.c */
724int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
725
726static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
727{
728	if (fh_len < sizeof(struct ovl_fh))
729		return -EINVAL;
730
731	return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
732}
733
734struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
735				  struct vfsmount *mnt, bool connected);
736int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
737			struct dentry *upperdentry, struct ovl_path **stackp);
738int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
739		      enum ovl_xattr ox, const struct ovl_fh *fh,
740		      bool is_upper, bool set);
741int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry,
742			    enum ovl_xattr ox, struct dentry *real,
743			    bool is_upper, bool set);
744struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
745			       bool connected);
746int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
747int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
748int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
749		       struct qstr *name);
750struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
751struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
752				struct dentry *origin, bool verify);
753int ovl_path_next(int idx, struct dentry *dentry, struct path *path,
754		  const struct ovl_layer **layer);
755int ovl_verify_lowerdata(struct dentry *dentry);
756struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
757			  unsigned int flags);
758bool ovl_lower_positive(struct dentry *dentry);
759
760static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper,
761				       const struct ovl_fh *fh, bool set)
762{
763	return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set);
764}
765
766static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
767				    struct dentry *origin, bool set)
768{
769	return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin,
770				       false, set);
771}
772
773static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
774				   struct dentry *upper, bool set)
775{
776	return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper,
777				       true, set);
778}
779
780/* readdir.c */
781extern const struct file_operations ovl_dir_operations;
782struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
783int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
784void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
785			   struct list_head *list);
786void ovl_cache_free(struct list_head *list);
787void ovl_dir_cache_free(struct inode *inode);
788int ovl_check_d_type_supported(const struct path *realpath);
789int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent,
790			struct vfsmount *mnt, struct dentry *dentry, int level);
791int ovl_indexdir_cleanup(struct ovl_fs *ofs);
792
793/*
794 * Can we iterate real dir directly?
795 *
796 * Non-merge dir may contain whiteouts from a time it was a merge upper, before
797 * lower dir was removed under it and possibly before it was rotated from upper
798 * to lower layer.
799 */
800static inline bool ovl_dir_is_real(struct inode *dir)
801{
802	return !ovl_test_flag(OVL_WHITEOUTS, dir);
803}
804
805/* inode.c */
806int ovl_set_nlink_upper(struct dentry *dentry);
807int ovl_set_nlink_lower(struct dentry *dentry);
808unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
809			   struct dentry *upperdentry,
810			   unsigned int fallback);
811int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
812		   int mask);
813
814#ifdef CONFIG_FS_POSIX_ACL
815struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
816				 struct inode *inode, int type,
817				 bool rcu, bool noperm);
818static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
819						  bool rcu)
820{
821	return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true);
822}
823static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
824					    struct dentry *dentry, int type)
825{
826	return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false);
827}
828int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
829		struct posix_acl *acl, int type);
830struct posix_acl *ovl_get_acl_path(const struct path *path,
831				   const char *acl_name, bool noperm);
832#else
833#define ovl_get_inode_acl	NULL
834#define ovl_get_acl		NULL
835#define ovl_set_acl		NULL
836static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
837						 const char *acl_name,
838						 bool noperm)
839{
840	return NULL;
841}
842#endif
843
844int ovl_update_time(struct inode *inode, int flags);
845bool ovl_is_private_xattr(struct super_block *sb, const char *name);
846
847struct ovl_inode_params {
848	struct inode *newinode;
849	struct dentry *upperdentry;
850	struct ovl_entry *oe;
851	bool index;
852	char *redirect;
853	char *lowerdata_redirect;
854};
855void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
856		    unsigned long ino, int fsid);
857struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
858struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
859			       bool is_upper);
860bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
861struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
862struct inode *ovl_get_inode(struct super_block *sb,
863			    struct ovl_inode_params *oip);
864void ovl_copyattr(struct inode *to);
865
866/* vfs fileattr flags read from overlay.protattr xattr to ovl inode */
867#define OVL_PROT_I_FLAGS_MASK  (S_APPEND | S_IMMUTABLE)
868/* vfs fileattr flags copied from real to ovl inode */
869#define OVL_FATTR_I_FLAGS_MASK (OVL_PROT_I_FLAGS_MASK | S_SYNC | S_NOATIME)
870/* vfs inode flags copied from real to ovl inode */
871#define OVL_COPY_I_FLAGS_MASK  (OVL_FATTR_I_FLAGS_MASK | S_CASEFOLD)
872
873/*
874 * fileattr flags copied from lower to upper inode on copy up.
875 * We cannot copy up immutable/append-only flags, because that would prevent
876 * linking temp inode to upper dir, so we store them in xattr instead.
877 */
878#define OVL_COPY_FS_FLAGS_MASK	(FS_SYNC_FL | FS_NOATIME_FL)
879#define OVL_COPY_FSX_FLAGS_MASK	(FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
880#define OVL_PROT_FS_FLAGS_MASK  (FS_APPEND_FL | FS_IMMUTABLE_FL)
881#define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
882
883void ovl_check_protattr(struct inode *inode, struct dentry *upper);
884int ovl_set_protattr(struct inode *inode, struct dentry *upper,
885		      struct file_kattr *fa);
886
887static inline void ovl_copyflags(struct inode *from, struct inode *to)
888{
889	unsigned int mask = OVL_COPY_I_FLAGS_MASK;
890
891	inode_set_flags(to, from->i_flags & mask, mask);
892}
893
894/* dir.c */
895extern const struct inode_operations ovl_dir_inode_operations;
896int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir,
897			     struct dentry *dentry);
898struct ovl_cattr {
899	dev_t rdev;
900	umode_t mode;
901	const char *link;
902	struct dentry *hardlink;
903};
904
905#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
906
907struct dentry *ovl_create_real(struct ovl_fs *ofs,
908			       struct dentry *parent, struct dentry *newdentry,
909			       struct ovl_cattr *attr);
910int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir, struct dentry *dentry);
911#define OVL_TEMPNAME_SIZE 20
912void ovl_tempname(char name[OVL_TEMPNAME_SIZE]);
913struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
914			       struct ovl_cattr *attr);
915
916/* file.c */
917extern const struct file_operations ovl_file_operations;
918int ovl_real_fileattr_get(const struct path *realpath, struct file_kattr *fa);
919int ovl_real_fileattr_set(const struct path *realpath, struct file_kattr *fa);
920int ovl_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
921int ovl_fileattr_set(struct mnt_idmap *idmap,
922		     struct dentry *dentry, struct file_kattr *fa);
923struct ovl_file;
924struct ovl_file *ovl_file_alloc(struct file *realfile);
925void ovl_file_free(struct ovl_file *of);
926
927/* copy_up.c */
928int ovl_copy_up(struct dentry *dentry);
929int ovl_copy_up_with_data(struct dentry *dentry);
930int ovl_maybe_copy_up(struct dentry *dentry, int flags);
931int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
932int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
933struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct inode *realinode,
934				  bool is_upper);
935struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
936int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
937		      struct dentry *upper);
938
939/* export.c */
940extern const struct export_operations ovl_export_operations;
941extern const struct export_operations ovl_export_fid_operations;
942
943/* super.c */
944int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
945
946/* Will this overlay be forced to mount/remount ro? */
947static inline bool ovl_force_readonly(struct ovl_fs *ofs)
948{
949	return (!ovl_upper_mnt(ofs) || !ofs->workdir);
950}
951
952/* xattr.c */
953
954const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
955int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
956		struct iattr *attr);
957int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
958		struct kstat *stat, u32 request_mask, unsigned int flags);
959ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);