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1 /*
2  * fs/sdcardfs/sdcardfs.h
3  *
4  * The sdcardfs v2.0
5  *   This file system replaces the sdcard daemon on Android
6  *   On version 2.0, some of the daemon functions have been ported
7  *   to support the multi-user concepts of Android 4.4
8  *
9  * Copyright (c) 2013 Samsung Electronics Co. Ltd
10  *   Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
11  *               Sunghwan Yun, Sungjong Seo
12  *
13  * This program has been developed as a stackable file system based on
14  * the WrapFS which written by
15  *
16  * Copyright (c) 1998-2011 Erez Zadok
17  * Copyright (c) 2009     Shrikar Archak
18  * Copyright (c) 2003-2011 Stony Brook University
19  * Copyright (c) 2003-2011 The Research Foundation of SUNY
20  *
21  * This file is dual licensed.  It may be redistributed and/or modified
22  * under the terms of the Apache 2.0 License OR version 2 of the GNU
23  * General Public License.
24  */
25 
26 #ifndef _SDCARDFS_H_
27 #define _SDCARDFS_H_
28 
29 #include <linux/dcache.h>
30 #include <linux/file.h>
31 #include <linux/fs.h>
32 #include <linux/aio.h>
33 #include <linux/kref.h>
34 #include <linux/mm.h>
35 #include <linux/mount.h>
36 #include <linux/namei.h>
37 #include <linux/seq_file.h>
38 #include <linux/statfs.h>
39 #include <linux/fs_stack.h>
40 #include <linux/magic.h>
41 #include <linux/uaccess.h>
42 #include <linux/slab.h>
43 #include <linux/sched.h>
44 #include <linux/types.h>
45 #include <linux/security.h>
46 #include <linux/string.h>
47 #include <linux/list.h>
48 #include "multiuser.h"
49 
50 /* the file system name */
51 #define SDCARDFS_NAME "sdcardfs"
52 
53 /* sdcardfs root inode number */
54 #define SDCARDFS_ROOT_INO     1
55 
56 /* useful for tracking code reachability */
57 #define UDBG pr_default("DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
58 
59 #define SDCARDFS_DIRENT_SIZE 256
60 
61 /* temporary static uid settings for development */
62 #define AID_ROOT             0	/* uid for accessing /mnt/sdcard & extSdcard */
63 #define AID_MEDIA_RW      1023	/* internal media storage write access */
64 
65 #define AID_SDCARD_RW     1015	/* external storage write access */
66 #define AID_SDCARD_R      1028	/* external storage read access */
67 #define AID_SDCARD_PICS   1033	/* external storage photos access */
68 #define AID_SDCARD_AV     1034	/* external storage audio/video access */
69 #define AID_SDCARD_ALL    1035	/* access all users external storage */
70 #define AID_MEDIA_OBB     1059  /* obb files */
71 
72 #define AID_SDCARD_IMAGE  1057
73 
74 #define AID_PACKAGE_INFO  1027
75 
76 
77 /*
78  * Permissions are handled by our permission function.
79  * We don't want anyone who happens to look at our inode value to prematurely
80  * block access, so store more permissive values. These are probably never
81  * used.
82  */
83 #define fixup_tmp_permissions(x)	\
84 	do {						\
85 		(x)->i_uid = make_kuid(&init_user_ns,	\
86 				SDCARDFS_I(x)->data->d_uid);	\
87 		(x)->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW);	\
88 		(x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
89 	} while (0)
90 
91 /* OVERRIDE_CRED() and REVERT_CRED()
92  *	OVERRIDE_CRED()
93  *		backup original task->cred
94  *		and modifies task->cred->fsuid/fsgid to specified value.
95  *	REVERT_CRED()
96  *		restore original task->cred->fsuid/fsgid.
97  * These two macro should be used in pair, and OVERRIDE_CRED() should be
98  * placed at the beginning of a function, right after variable declaration.
99  */
100 #define OVERRIDE_CRED(sdcardfs_sbi, saved_cred, info)		\
101 	do {	\
102 		saved_cred = override_fsids(sdcardfs_sbi, info->data);	\
103 		if (!saved_cred)	\
104 			return -ENOMEM;	\
105 	} while (0)
106 
107 #define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred, info)	\
108 	do {	\
109 		saved_cred = override_fsids(sdcardfs_sbi, info->data);	\
110 		if (!saved_cred)	\
111 			return ERR_PTR(-ENOMEM);	\
112 	} while (0)
113 
114 #define REVERT_CRED(saved_cred)	revert_fsids(saved_cred)
115 
116 /* Android 5.0 support */
117 
118 /* Permission mode for a specific node. Controls how file permissions
119  * are derived for children nodes.
120  */
121 typedef enum {
122 	/* Nothing special; this node should just inherit from its parent. */
123 	PERM_INHERIT,
124 	/* This node is one level above a normal root; used for legacy layouts
125 	 * which use the first level to represent user_id.
126 	 */
127 	PERM_PRE_ROOT,
128 	/* This node is "/" */
129 	PERM_ROOT,
130 	/* This node is "/Android" */
131 	PERM_ANDROID,
132 	/* This node is "/Android/data" */
133 	PERM_ANDROID_DATA,
134 	/* This node is "/Android/obb" */
135 	PERM_ANDROID_OBB,
136 	/* This node is "/Android/media" */
137 	PERM_ANDROID_MEDIA,
138 	/* This node is "/Android/[data|media|obb]/[package]" */
139 	PERM_ANDROID_PACKAGE,
140 	/* This node is "/Android/[data|media|obb]/[package]/cache" */
141 	PERM_ANDROID_PACKAGE_CACHE,
142 } perm_t;
143 
144 struct sdcardfs_sb_info;
145 struct sdcardfs_mount_options;
146 struct sdcardfs_inode_info;
147 struct sdcardfs_inode_data;
148 
149 /* Do not directly use this function. Use OVERRIDE_CRED() instead. */
150 const struct cred *override_fsids(struct sdcardfs_sb_info *sbi,
151 			struct sdcardfs_inode_data *data);
152 /* Do not directly use this function, use REVERT_CRED() instead. */
153 void revert_fsids(const struct cred *old_cred);
154 
155 /* operations vectors defined in specific files */
156 extern const struct file_operations sdcardfs_main_fops;
157 extern const struct file_operations sdcardfs_dir_fops;
158 extern const struct inode_operations sdcardfs_main_iops;
159 extern const struct inode_operations sdcardfs_dir_iops;
160 extern const struct inode_operations sdcardfs_symlink_iops;
161 extern const struct super_operations sdcardfs_sops;
162 extern const struct dentry_operations sdcardfs_ci_dops;
163 extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
164 extern const struct vm_operations_struct sdcardfs_vm_ops;
165 
166 extern int sdcardfs_init_inode_cache(void);
167 extern void sdcardfs_destroy_inode_cache(void);
168 extern int sdcardfs_init_dentry_cache(void);
169 extern void sdcardfs_destroy_dentry_cache(void);
170 extern int new_dentry_private_data(struct dentry *dentry);
171 extern void free_dentry_private_data(struct dentry *dentry);
172 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
173 				unsigned int flags);
174 extern struct inode *sdcardfs_iget(struct super_block *sb,
175 				 struct inode *lower_inode, userid_t id);
176 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
177 			    struct path *lower_path, userid_t id);
178 
179 /* file private data */
180 struct sdcardfs_file_info {
181 	struct file *lower_file;
182 	const struct vm_operations_struct *lower_vm_ops;
183 };
184 
185 struct sdcardfs_inode_data {
186 	struct kref refcount;
187 	bool abandoned;
188 
189 	perm_t perm;
190 	userid_t userid;
191 	uid_t d_uid;
192 	bool under_android;
193 	bool under_cache;
194 	bool under_obb;
195 };
196 
197 /* sdcardfs inode data in memory */
198 struct sdcardfs_inode_info {
199 	struct inode *lower_inode;
200 	/* state derived based on current position in hierarchy */
201 	struct sdcardfs_inode_data *data;
202 
203 	/* top folder for ownership */
204 	spinlock_t top_lock;
205 	struct sdcardfs_inode_data *top_data;
206 
207 	struct inode vfs_inode;
208 };
209 
210 
211 /* sdcardfs dentry data in memory */
212 struct sdcardfs_dentry_info {
213 	spinlock_t lock;	/* protects lower_path */
214 	struct path lower_path;
215 	struct path orig_path;
216 };
217 
218 struct sdcardfs_mount_options {
219 	uid_t fs_low_uid;
220 	gid_t fs_low_gid;
221 	userid_t fs_user_id;
222 	bool multiuser;
223 	bool gid_derivation;
224 	bool default_normal;
225 	unsigned int reserved_mb;
226 };
227 
228 struct sdcardfs_vfsmount_options {
229 	gid_t gid;
230 	mode_t mask;
231 };
232 
233 extern int parse_options_remount(struct super_block *sb, char *options, int silent,
234 		struct sdcardfs_vfsmount_options *vfsopts);
235 
236 /* sdcardfs super-block data in memory */
237 struct sdcardfs_sb_info {
238 	struct super_block *sb;
239 	struct super_block *lower_sb;
240 	/* derived perm policy : some of options have been added
241 	 * to sdcardfs_mount_options (Android 4.4 support)
242 	 */
243 	struct sdcardfs_mount_options options;
244 	spinlock_t lock;	/* protects obbpath */
245 	char *obbpath_s;
246 	struct path obbpath;
247 	void *pkgl_id;
248 	struct list_head list;
249 };
250 
251 /*
252  * inode to private data
253  *
254  * Since we use containers and the struct inode is _inside_ the
255  * sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
256  * inode pointer), return a valid non-NULL pointer.
257  */
SDCARDFS_I(const struct inode * inode)258 static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
259 {
260 	return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
261 }
262 
263 /* dentry to private data */
264 #define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
265 
266 /* superblock to private data */
267 #define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
268 
269 /* file to private Data */
270 #define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
271 
272 /* file to lower file */
sdcardfs_lower_file(const struct file * f)273 static inline struct file *sdcardfs_lower_file(const struct file *f)
274 {
275 	return SDCARDFS_F(f)->lower_file;
276 }
277 
sdcardfs_set_lower_file(struct file * f,struct file * val)278 static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
279 {
280 	SDCARDFS_F(f)->lower_file = val;
281 }
282 
283 /* inode to lower inode. */
sdcardfs_lower_inode(const struct inode * i)284 static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
285 {
286 	return SDCARDFS_I(i)->lower_inode;
287 }
288 
sdcardfs_set_lower_inode(struct inode * i,struct inode * val)289 static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
290 {
291 	SDCARDFS_I(i)->lower_inode = val;
292 }
293 
294 /* superblock to lower superblock */
sdcardfs_lower_super(const struct super_block * sb)295 static inline struct super_block *sdcardfs_lower_super(
296 	const struct super_block *sb)
297 {
298 	return SDCARDFS_SB(sb)->lower_sb;
299 }
300 
sdcardfs_set_lower_super(struct super_block * sb,struct super_block * val)301 static inline void sdcardfs_set_lower_super(struct super_block *sb,
302 					  struct super_block *val)
303 {
304 	SDCARDFS_SB(sb)->lower_sb = val;
305 }
306 
307 /* path based (dentry/mnt) macros */
pathcpy(struct path * dst,const struct path * src)308 static inline void pathcpy(struct path *dst, const struct path *src)
309 {
310 	dst->dentry = src->dentry;
311 	dst->mnt = src->mnt;
312 }
313 
314 /* sdcardfs_get_pname functions calls path_get()
315  * therefore, the caller must call "proper" path_put functions
316  */
317 #define SDCARDFS_DENT_FUNC(pname) \
318 static inline void sdcardfs_get_##pname(const struct dentry *dent, \
319 					struct path *pname) \
320 { \
321 	spin_lock(&SDCARDFS_D(dent)->lock); \
322 	pathcpy(pname, &SDCARDFS_D(dent)->pname); \
323 	path_get(pname); \
324 	spin_unlock(&SDCARDFS_D(dent)->lock); \
325 	return; \
326 } \
327 static inline void sdcardfs_put_##pname(const struct dentry *dent, \
328 					struct path *pname) \
329 { \
330 	path_put(pname); \
331 	return; \
332 } \
333 static inline void sdcardfs_set_##pname(const struct dentry *dent, \
334 					struct path *pname) \
335 { \
336 	spin_lock(&SDCARDFS_D(dent)->lock); \
337 	pathcpy(&SDCARDFS_D(dent)->pname, pname); \
338 	spin_unlock(&SDCARDFS_D(dent)->lock); \
339 	return; \
340 } \
341 static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
342 { \
343 	spin_lock(&SDCARDFS_D(dent)->lock); \
344 	SDCARDFS_D(dent)->pname.dentry = NULL; \
345 	SDCARDFS_D(dent)->pname.mnt = NULL; \
346 	spin_unlock(&SDCARDFS_D(dent)->lock); \
347 	return; \
348 } \
349 static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
350 { \
351 	struct path pname; \
352 	spin_lock(&SDCARDFS_D(dent)->lock); \
353 	if (SDCARDFS_D(dent)->pname.dentry) { \
354 		pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
355 		SDCARDFS_D(dent)->pname.dentry = NULL; \
356 		SDCARDFS_D(dent)->pname.mnt = NULL; \
357 		spin_unlock(&SDCARDFS_D(dent)->lock); \
358 		path_put(&pname); \
359 	} else \
360 		spin_unlock(&SDCARDFS_D(dent)->lock); \
361 	return; \
362 }
363 
364 SDCARDFS_DENT_FUNC(lower_path)
SDCARDFS_DENT_FUNC(orig_path)365 SDCARDFS_DENT_FUNC(orig_path)
366 
367 static inline bool sbinfo_has_sdcard_magic(struct sdcardfs_sb_info *sbinfo)
368 {
369 	return sbinfo && sbinfo->sb
370 			&& sbinfo->sb->s_magic == SDCARDFS_SUPER_MAGIC;
371 }
372 
data_get(struct sdcardfs_inode_data * data)373 static inline struct sdcardfs_inode_data *data_get(
374 		struct sdcardfs_inode_data *data)
375 {
376 	if (data)
377 		kref_get(&data->refcount);
378 	return data;
379 }
380 
top_data_get(struct sdcardfs_inode_info * info)381 static inline struct sdcardfs_inode_data *top_data_get(
382 		struct sdcardfs_inode_info *info)
383 {
384 	struct sdcardfs_inode_data *top_data;
385 
386 	spin_lock(&info->top_lock);
387 	top_data = data_get(info->top_data);
388 	spin_unlock(&info->top_lock);
389 	return top_data;
390 }
391 
392 extern void data_release(struct kref *ref);
393 
data_put(struct sdcardfs_inode_data * data)394 static inline void data_put(struct sdcardfs_inode_data *data)
395 {
396 	kref_put(&data->refcount, data_release);
397 }
398 
release_own_data(struct sdcardfs_inode_info * info)399 static inline void release_own_data(struct sdcardfs_inode_info *info)
400 {
401 	/*
402 	 * This happens exactly once per inode. At this point, the inode that
403 	 * originally held this data is about to be freed, and all references
404 	 * to it are held as a top value, and will likely be released soon.
405 	 */
406 	info->data->abandoned = true;
407 	data_put(info->data);
408 }
409 
set_top(struct sdcardfs_inode_info * info,struct sdcardfs_inode_info * top_owner)410 static inline void set_top(struct sdcardfs_inode_info *info,
411 			struct sdcardfs_inode_info *top_owner)
412 {
413 	struct sdcardfs_inode_data *old_top;
414 	struct sdcardfs_inode_data *new_top = NULL;
415 
416 	if (top_owner)
417 		new_top = top_data_get(top_owner);
418 
419 	spin_lock(&info->top_lock);
420 	old_top = info->top_data;
421 	info->top_data = new_top;
422 	if (old_top)
423 		data_put(old_top);
424 	spin_unlock(&info->top_lock);
425 }
426 
get_gid(struct vfsmount * mnt,struct super_block * sb,struct sdcardfs_inode_data * data)427 static inline int get_gid(struct vfsmount *mnt,
428 		struct super_block *sb,
429 		struct sdcardfs_inode_data *data)
430 {
431 	struct sdcardfs_vfsmount_options *vfsopts = mnt->data;
432 	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(sb);
433 
434 	if (vfsopts->gid == AID_SDCARD_RW && !sbi->options.default_normal)
435 		/* As an optimization, certain trusted system components only run
436 		 * as owner but operate across all users. Since we're now handing
437 		 * out the sdcard_rw GID only to trusted apps, we're okay relaxing
438 		 * the user boundary enforcement for the default view. The UIDs
439 		 * assigned to app directories are still multiuser aware.
440 		 */
441 		return AID_SDCARD_RW;
442 	else
443 		return multiuser_get_uid(data->userid, vfsopts->gid);
444 }
445 
get_mode(struct vfsmount * mnt,struct sdcardfs_inode_info * info,struct sdcardfs_inode_data * data)446 static inline int get_mode(struct vfsmount *mnt,
447 		struct sdcardfs_inode_info *info,
448 		struct sdcardfs_inode_data *data)
449 {
450 	int owner_mode;
451 	int filtered_mode;
452 	struct sdcardfs_vfsmount_options *opts = mnt->data;
453 	int visible_mode = 0775 & ~opts->mask;
454 
455 
456 	if (data->perm == PERM_PRE_ROOT) {
457 		/* Top of multi-user view should always be visible to ensure
458 		* secondary users can traverse inside.
459 		*/
460 		visible_mode = 0711;
461 	} else if (data->under_android) {
462 		/* Block "other" access to Android directories, since only apps
463 		* belonging to a specific user should be in there; we still
464 		* leave +x open for the default view.
465 		*/
466 		if (opts->gid == AID_SDCARD_RW)
467 			visible_mode = visible_mode & ~0006;
468 		else
469 			visible_mode = visible_mode & ~0007;
470 	}
471 	owner_mode = info->lower_inode->i_mode & 0700;
472 	filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
473 	return filtered_mode;
474 }
475 
has_graft_path(const struct dentry * dent)476 static inline int has_graft_path(const struct dentry *dent)
477 {
478 	int ret = 0;
479 
480 	spin_lock(&SDCARDFS_D(dent)->lock);
481 	if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
482 		ret = 1;
483 	spin_unlock(&SDCARDFS_D(dent)->lock);
484 
485 	return ret;
486 }
487 
sdcardfs_get_real_lower(const struct dentry * dent,struct path * real_lower)488 static inline void sdcardfs_get_real_lower(const struct dentry *dent,
489 						struct path *real_lower)
490 {
491 	/* in case of a local obb dentry
492 	 * the orig_path should be returned
493 	 */
494 	if (has_graft_path(dent))
495 		sdcardfs_get_orig_path(dent, real_lower);
496 	else
497 		sdcardfs_get_lower_path(dent, real_lower);
498 }
499 
sdcardfs_put_real_lower(const struct dentry * dent,struct path * real_lower)500 static inline void sdcardfs_put_real_lower(const struct dentry *dent,
501 						struct path *real_lower)
502 {
503 	if (has_graft_path(dent))
504 		sdcardfs_put_orig_path(dent, real_lower);
505 	else
506 		sdcardfs_put_lower_path(dent, real_lower);
507 }
508 
509 extern struct mutex sdcardfs_super_list_lock;
510 extern struct list_head sdcardfs_super_list;
511 
512 /* for packagelist.c */
513 extern appid_t get_appid(const char *app_name);
514 extern appid_t get_ext_gid(const char *app_name);
515 extern appid_t is_excluded(const char *app_name, userid_t userid);
516 extern int check_caller_access_to_name(struct inode *parent_node, const struct qstr *name);
517 extern int packagelist_init(void);
518 extern void packagelist_exit(void);
519 
520 /* for derived_perm.c */
521 #define BY_NAME		(1 << 0)
522 #define BY_USERID	(1 << 1)
523 struct limit_search {
524 	unsigned int flags;
525 	struct qstr name;
526 	userid_t userid;
527 };
528 
529 extern void setup_derived_state(struct inode *inode, perm_t perm,
530 			userid_t userid, uid_t uid);
531 extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
532 extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, const struct qstr *name);
533 extern void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit);
534 
535 extern void update_derived_permission_lock(struct dentry *dentry);
536 void fixup_lower_ownership(struct dentry *dentry, const char *name);
537 extern int need_graft_path(struct dentry *dentry);
538 extern int is_base_obbpath(struct dentry *dentry);
539 extern int is_obbpath_invalid(struct dentry *dentry);
540 extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
541 
542 /* locking helpers */
lock_parent(struct dentry * dentry)543 static inline struct dentry *lock_parent(struct dentry *dentry)
544 {
545 	struct dentry *dir = dget_parent(dentry);
546 
547 	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
548 	return dir;
549 }
550 
unlock_dir(struct dentry * dir)551 static inline void unlock_dir(struct dentry *dir)
552 {
553 	inode_unlock(d_inode(dir));
554 	dput(dir);
555 }
556 
prepare_dir(const char * path_s,uid_t uid,gid_t gid,mode_t mode)557 static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
558 {
559 	int err;
560 	struct dentry *dent;
561 	struct iattr attrs;
562 	struct path parent;
563 
564 	dent = kern_path_locked(path_s, &parent);
565 	if (IS_ERR(dent)) {
566 		err = PTR_ERR(dent);
567 		if (err == -EEXIST)
568 			err = 0;
569 		goto out_unlock;
570 	}
571 
572 	err = vfs_mkdir2(parent.mnt, d_inode(parent.dentry), dent, mode);
573 	if (err) {
574 		if (err == -EEXIST)
575 			err = 0;
576 		goto out_dput;
577 	}
578 
579 	attrs.ia_uid = make_kuid(&init_user_ns, uid);
580 	attrs.ia_gid = make_kgid(&init_user_ns, gid);
581 	attrs.ia_valid = ATTR_UID | ATTR_GID;
582 	inode_lock(d_inode(dent));
583 	notify_change2(parent.mnt, dent, &attrs, NULL);
584 	inode_unlock(d_inode(dent));
585 
586 out_dput:
587 	dput(dent);
588 
589 out_unlock:
590 	/* parent dentry locked by lookup_create */
591 	inode_unlock(d_inode(parent.dentry));
592 	path_put(&parent);
593 	return err;
594 }
595 
596 /*
597  * Return 1, if a disk has enough free space, otherwise 0.
598  * We assume that any files can not be overwritten.
599  */
check_min_free_space(struct dentry * dentry,size_t size,int dir)600 static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
601 {
602 	int err;
603 	struct path lower_path;
604 	struct kstatfs statfs;
605 	u64 avail;
606 	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
607 
608 	if (sbi->options.reserved_mb) {
609 		/* Get fs stat of lower filesystem. */
610 		sdcardfs_get_lower_path(dentry, &lower_path);
611 		err = vfs_statfs(&lower_path, &statfs);
612 		sdcardfs_put_lower_path(dentry, &lower_path);
613 
614 		if (unlikely(err))
615 			return 0;
616 
617 		/* Invalid statfs informations. */
618 		if (unlikely(statfs.f_bsize == 0))
619 			return 0;
620 
621 		/* if you are checking directory, set size to f_bsize. */
622 		if (unlikely(dir))
623 			size = statfs.f_bsize;
624 
625 		/* available size */
626 		avail = statfs.f_bavail * statfs.f_bsize;
627 
628 		/* not enough space */
629 		if ((u64)size > avail)
630 			return 0;
631 
632 		/* enough space */
633 		if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
634 			return 1;
635 
636 		return 0;
637 	} else
638 		return 1;
639 }
640 
641 /*
642  * Copies attrs and maintains sdcardfs managed attrs
643  * Since our permission check handles all special permissions, set those to be open
644  */
sdcardfs_copy_and_fix_attrs(struct inode * dest,const struct inode * src)645 static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
646 {
647 	dest->i_mode = (src->i_mode  & S_IFMT) | S_IRWXU | S_IRWXG |
648 			S_IROTH | S_IXOTH; /* 0775 */
649 	dest->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(dest)->data->d_uid);
650 	dest->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW);
651 	dest->i_rdev = src->i_rdev;
652 	dest->i_atime = src->i_atime;
653 	dest->i_mtime = src->i_mtime;
654 	dest->i_ctime = src->i_ctime;
655 	dest->i_blkbits = src->i_blkbits;
656 	dest->i_flags = src->i_flags;
657 	set_nlink(dest, src->i_nlink);
658 }
659 
str_case_eq(const char * s1,const char * s2)660 static inline bool str_case_eq(const char *s1, const char *s2)
661 {
662 	return !strcasecmp(s1, s2);
663 }
664 
str_n_case_eq(const char * s1,const char * s2,size_t len)665 static inline bool str_n_case_eq(const char *s1, const char *s2, size_t len)
666 {
667 	return !strncasecmp(s1, s2, len);
668 }
669 
qstr_case_eq(const struct qstr * q1,const struct qstr * q2)670 static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2)
671 {
672 	return q1->len == q2->len && str_n_case_eq(q1->name, q2->name, q2->len);
673 }
674 
675 #define QSTR_LITERAL(string) QSTR_INIT(string, sizeof(string)-1)
676 
677 #endif	/* not _SDCARDFS_H_ */
678