1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_DCACHE_H
3 #define __LINUX_DCACHE_H
4
5 #include <linux/atomic.h>
6 #include <linux/list.h>
7 #include <linux/math.h>
8 #include <linux/rculist.h>
9 #include <linux/rculist_bl.h>
10 #include <linux/spinlock.h>
11 #include <linux/seqlock.h>
12 #include <linux/cache.h>
13 #include <linux/rcupdate.h>
14 #include <linux/lockref.h>
15 #include <linux/stringhash.h>
16 #include <linux/wait.h>
17 #include <linux/android_kabi.h>
18
19 struct path;
20 struct file;
21 struct vfsmount;
22
23 /*
24 * linux/include/linux/dcache.h
25 *
26 * Dirent cache data structures
27 *
28 * (C) Copyright 1997 Thomas Schoebel-Theuer,
29 * with heavy changes by Linus Torvalds
30 */
31
32 #define IS_ROOT(x) ((x) == (x)->d_parent)
33
34 /* The hash is always the low bits of hash_len */
35 #ifdef __LITTLE_ENDIAN
36 #define HASH_LEN_DECLARE u32 hash; u32 len
37 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
38 #else
39 #define HASH_LEN_DECLARE u32 len; u32 hash
40 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
41 #endif
42
43 /*
44 * "quick string" -- eases parameter passing, but more importantly
45 * saves "metadata" about the string (ie length and the hash).
46 *
47 * hash comes first so it snuggles against d_parent in the
48 * dentry.
49 */
50 struct qstr {
51 union {
52 struct {
53 HASH_LEN_DECLARE;
54 };
55 u64 hash_len;
56 };
57 const unsigned char *name;
58 };
59
60 #define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
61 #define QSTR(n) (struct qstr)QSTR_INIT(n, strlen(n))
62
63 extern const struct qstr empty_name;
64 extern const struct qstr slash_name;
65 extern const struct qstr dotdot_name;
66
67 /*
68 * Try to keep struct dentry aligned on 64 byte cachelines (this will
69 * give reasonable cacheline footprint with larger lines without the
70 * large memory footprint increase).
71 */
72 #ifdef CONFIG_64BIT
73 # define DNAME_INLINE_LEN 40 /* 192 bytes */
74 #else
75 # ifdef CONFIG_SMP
76 # define DNAME_INLINE_LEN 36 /* 128 bytes */
77 # else
78 # define DNAME_INLINE_LEN 44 /* 128 bytes */
79 # endif
80 #endif
81
82 #define d_lock d_lockref.lock
83
84 struct dentry {
85 /* RCU lookup touched fields */
86 unsigned int d_flags; /* protected by d_lock */
87 seqcount_spinlock_t d_seq; /* per dentry seqlock */
88 struct hlist_bl_node d_hash; /* lookup hash list */
89 struct dentry *d_parent; /* parent directory */
90 struct qstr d_name;
91 struct inode *d_inode; /* Where the name belongs to - NULL is
92 * negative */
93 unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
94 /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */
95
96 /* Ref lookup also touches following */
97 const struct dentry_operations *d_op;
98 struct super_block *d_sb; /* The root of the dentry tree */
99 unsigned long d_time; /* used by d_revalidate */
100 void *d_fsdata; /* fs-specific data */
101 /* --- cacheline 2 boundary (128 bytes) --- */
102 struct lockref d_lockref; /* per-dentry lock and refcount
103 * keep separate from RCU lookup area if
104 * possible!
105 */
106
107 union {
108 struct list_head d_lru; /* LRU list */
109 wait_queue_head_t *d_wait; /* in-lookup ones only */
110 };
111 struct hlist_node d_sib; /* child of parent list */
112 struct hlist_head d_children; /* our children */
113 /*
114 * d_alias and d_rcu can share memory
115 */
116 union {
117 struct hlist_node d_alias; /* inode alias list */
118 struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */
119 struct rcu_head d_rcu;
120 } d_u;
121
122 ANDROID_KABI_RESERVE(1);
123 ANDROID_KABI_RESERVE(2);
124 };
125
126 /*
127 * dentry->d_lock spinlock nesting subclasses:
128 *
129 * 0: normal
130 * 1: nested
131 */
132 enum dentry_d_lock_class
133 {
134 DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
135 DENTRY_D_LOCK_NESTED
136 };
137
138 enum d_real_type {
139 D_REAL_DATA,
140 D_REAL_METADATA,
141 };
142
143 struct dentry_operations {
144 int (*d_revalidate)(struct dentry *, unsigned int);
145 int (*d_weak_revalidate)(struct dentry *, unsigned int);
146 int (*d_hash)(const struct dentry *, struct qstr *);
147 int (*d_compare)(const struct dentry *,
148 unsigned int, const char *, const struct qstr *);
149 int (*d_delete)(const struct dentry *);
150 int (*d_init)(struct dentry *);
151 void (*d_release)(struct dentry *);
152 void (*d_prune)(struct dentry *);
153 void (*d_iput)(struct dentry *, struct inode *);
154 char *(*d_dname)(struct dentry *, char *, int);
155 struct vfsmount *(*d_automount)(struct path *);
156 int (*d_manage)(const struct path *, bool);
157 struct dentry *(*d_real)(struct dentry *, enum d_real_type type);
158 int (*d_canonical_path)(const struct path *, struct path *);
159
160 ANDROID_KABI_RESERVE(1);
161 ANDROID_KABI_RESERVE(2);
162 ANDROID_KABI_RESERVE(3);
163 ANDROID_KABI_RESERVE(4);
164 } ____cacheline_aligned;
165
166 /*
167 * Locking rules for dentry_operations callbacks are to be found in
168 * Documentation/filesystems/locking.rst. Keep it updated!
169 *
170 * FUrther descriptions are found in Documentation/filesystems/vfs.rst.
171 * Keep it updated too!
172 */
173
174 /* d_flags entries */
175 #define DCACHE_OP_HASH BIT(0)
176 #define DCACHE_OP_COMPARE BIT(1)
177 #define DCACHE_OP_REVALIDATE BIT(2)
178 #define DCACHE_OP_DELETE BIT(3)
179 #define DCACHE_OP_PRUNE BIT(4)
180
181 #define DCACHE_DISCONNECTED BIT(5)
182 /* This dentry is possibly not currently connected to the dcache tree, in
183 * which case its parent will either be itself, or will have this flag as
184 * well. nfsd will not use a dentry with this bit set, but will first
185 * endeavour to clear the bit either by discovering that it is connected,
186 * or by performing lookup operations. Any filesystem which supports
187 * nfsd_operations MUST have a lookup function which, if it finds a
188 * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
189 * dentry into place and return that dentry rather than the passed one,
190 * typically using d_splice_alias. */
191
192 #define DCACHE_REFERENCED BIT(6) /* Recently used, don't discard. */
193
194 #define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */
195
196 #define DCACHE_CANT_MOUNT BIT(8)
197 #define DCACHE_GENOCIDE BIT(9)
198 #define DCACHE_SHRINK_LIST BIT(10)
199
200 #define DCACHE_OP_WEAK_REVALIDATE BIT(11)
201
202 #define DCACHE_NFSFS_RENAMED BIT(12)
203 /* this dentry has been "silly renamed" and has to be deleted on the last
204 * dput() */
205 #define DCACHE_FSNOTIFY_PARENT_WATCHED BIT(14)
206 /* Parent inode is watched by some fsnotify listener */
207
208 #define DCACHE_DENTRY_KILLED BIT(15)
209
210 #define DCACHE_MOUNTED BIT(16) /* is a mountpoint */
211 #define DCACHE_NEED_AUTOMOUNT BIT(17) /* handle automount on this dir */
212 #define DCACHE_MANAGE_TRANSIT BIT(18) /* manage transit from this dirent */
213 #define DCACHE_MANAGED_DENTRY \
214 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
215
216 #define DCACHE_LRU_LIST BIT(19)
217
218 #define DCACHE_ENTRY_TYPE (7 << 20) /* bits 20..22 are for storing type: */
219 #define DCACHE_MISS_TYPE (0 << 20) /* Negative dentry */
220 #define DCACHE_WHITEOUT_TYPE (1 << 20) /* Whiteout dentry (stop pathwalk) */
221 #define DCACHE_DIRECTORY_TYPE (2 << 20) /* Normal directory */
222 #define DCACHE_AUTODIR_TYPE (3 << 20) /* Lookupless directory (presumed automount) */
223 #define DCACHE_REGULAR_TYPE (4 << 20) /* Regular file type */
224 #define DCACHE_SPECIAL_TYPE (5 << 20) /* Other file type */
225 #define DCACHE_SYMLINK_TYPE (6 << 20) /* Symlink */
226
227 #define DCACHE_NOKEY_NAME BIT(25) /* Encrypted name encoded without key */
228 #define DCACHE_OP_REAL BIT(26)
229
230 #define DCACHE_PAR_LOOKUP BIT(28) /* being looked up (with parent locked shared) */
231 #define DCACHE_DENTRY_CURSOR BIT(29)
232 #define DCACHE_NORCU BIT(30) /* No RCU delay for freeing */
233
234 extern seqlock_t rename_lock;
235
236 /*
237 * These are the low-level FS interfaces to the dcache..
238 */
239 extern void d_instantiate(struct dentry *, struct inode *);
240 extern void d_instantiate_new(struct dentry *, struct inode *);
241 extern void __d_drop(struct dentry *dentry);
242 extern void d_drop(struct dentry *dentry);
243 extern void d_delete(struct dentry *);
244 extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
245
246 /* allocate/de-allocate */
247 extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
248 extern struct dentry * d_alloc_anon(struct super_block *);
249 extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
250 wait_queue_head_t *);
251 extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
252 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
253 extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent,
254 const struct qstr *name);
255 extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
256 extern struct dentry *d_find_any_alias(struct inode *inode);
257 extern struct dentry * d_obtain_alias(struct inode *);
258 extern struct dentry * d_obtain_root(struct inode *);
259 extern void shrink_dcache_sb(struct super_block *);
260 extern void shrink_dcache_parent(struct dentry *);
261 extern void d_invalidate(struct dentry *);
262
263 /* only used at mount-time */
264 extern struct dentry * d_make_root(struct inode *);
265
266 extern void d_mark_tmpfile(struct file *, struct inode *);
267 extern void d_tmpfile(struct file *, struct inode *);
268
269 extern struct dentry *d_find_alias(struct inode *);
270 extern void d_prune_aliases(struct inode *);
271
272 extern struct dentry *d_find_alias_rcu(struct inode *);
273
274 /* test whether we have any submounts in a subdir tree */
275 extern int path_has_submounts(const struct path *);
276
277 /*
278 * This adds the entry to the hash queues.
279 */
280 extern void d_rehash(struct dentry *);
281
282 extern void d_add(struct dentry *, struct inode *);
283
284 /* used for rename() and baskets */
285 extern void d_move(struct dentry *, struct dentry *);
286 extern void d_exchange(struct dentry *, struct dentry *);
287 extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
288
289 extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
290 extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
291
d_count(const struct dentry * dentry)292 static inline unsigned d_count(const struct dentry *dentry)
293 {
294 return dentry->d_lockref.count;
295 }
296
297 ino_t d_parent_ino(struct dentry *dentry);
298
299 /*
300 * helper function for dentry_operations.d_dname() members
301 */
302 extern __printf(3, 4)
303 char *dynamic_dname(char *, int, const char *, ...);
304
305 extern char *__d_path(const struct path *, const struct path *, char *, int);
306 extern char *d_absolute_path(const struct path *, char *, int);
307 extern char *d_path(const struct path *, char *, int);
308 extern char *dentry_path_raw(const struct dentry *, char *, int);
309 extern char *dentry_path(const struct dentry *, char *, int);
310
311 /* Allocation counts.. */
312
313 /**
314 * dget_dlock - get a reference to a dentry
315 * @dentry: dentry to get a reference to
316 *
317 * Given a live dentry, increment the reference count and return the dentry.
318 * Caller must hold @dentry->d_lock. Making sure that dentry is alive is
319 * caller's resonsibility. There are many conditions sufficient to guarantee
320 * that; e.g. anything with non-negative refcount is alive, so's anything
321 * hashed, anything positive, anyone's parent, etc.
322 */
dget_dlock(struct dentry * dentry)323 static inline struct dentry *dget_dlock(struct dentry *dentry)
324 {
325 dentry->d_lockref.count++;
326 return dentry;
327 }
328
329
330 /**
331 * dget - get a reference to a dentry
332 * @dentry: dentry to get a reference to
333 *
334 * Given a dentry or %NULL pointer increment the reference count
335 * if appropriate and return the dentry. A dentry will not be
336 * destroyed when it has references. Conversely, a dentry with
337 * no references can disappear for any number of reasons, starting
338 * with memory pressure. In other words, that primitive is
339 * used to clone an existing reference; using it on something with
340 * zero refcount is a bug.
341 *
342 * NOTE: it will spin if @dentry->d_lock is held. From the deadlock
343 * avoidance point of view it is equivalent to spin_lock()/increment
344 * refcount/spin_unlock(), so calling it under @dentry->d_lock is
345 * always a bug; so's calling it under ->d_lock on any of its descendents.
346 *
347 */
dget(struct dentry * dentry)348 static inline struct dentry *dget(struct dentry *dentry)
349 {
350 if (dentry)
351 lockref_get(&dentry->d_lockref);
352 return dentry;
353 }
354
355 extern struct dentry *dget_parent(struct dentry *dentry);
356
357 /**
358 * d_unhashed - is dentry hashed
359 * @dentry: entry to check
360 *
361 * Returns true if the dentry passed is not currently hashed.
362 */
d_unhashed(const struct dentry * dentry)363 static inline int d_unhashed(const struct dentry *dentry)
364 {
365 return hlist_bl_unhashed(&dentry->d_hash);
366 }
367
d_unlinked(const struct dentry * dentry)368 static inline int d_unlinked(const struct dentry *dentry)
369 {
370 return d_unhashed(dentry) && !IS_ROOT(dentry);
371 }
372
cant_mount(const struct dentry * dentry)373 static inline int cant_mount(const struct dentry *dentry)
374 {
375 return (dentry->d_flags & DCACHE_CANT_MOUNT);
376 }
377
dont_mount(struct dentry * dentry)378 static inline void dont_mount(struct dentry *dentry)
379 {
380 spin_lock(&dentry->d_lock);
381 dentry->d_flags |= DCACHE_CANT_MOUNT;
382 spin_unlock(&dentry->d_lock);
383 }
384
385 extern void __d_lookup_unhash_wake(struct dentry *dentry);
386
d_in_lookup(const struct dentry * dentry)387 static inline int d_in_lookup(const struct dentry *dentry)
388 {
389 return dentry->d_flags & DCACHE_PAR_LOOKUP;
390 }
391
d_lookup_done(struct dentry * dentry)392 static inline void d_lookup_done(struct dentry *dentry)
393 {
394 if (unlikely(d_in_lookup(dentry)))
395 __d_lookup_unhash_wake(dentry);
396 }
397
398 extern void dput(struct dentry *);
399
d_managed(const struct dentry * dentry)400 static inline bool d_managed(const struct dentry *dentry)
401 {
402 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
403 }
404
d_mountpoint(const struct dentry * dentry)405 static inline bool d_mountpoint(const struct dentry *dentry)
406 {
407 return dentry->d_flags & DCACHE_MOUNTED;
408 }
409
410 /*
411 * Directory cache entry type accessor functions.
412 */
__d_entry_type(const struct dentry * dentry)413 static inline unsigned __d_entry_type(const struct dentry *dentry)
414 {
415 return dentry->d_flags & DCACHE_ENTRY_TYPE;
416 }
417
d_is_miss(const struct dentry * dentry)418 static inline bool d_is_miss(const struct dentry *dentry)
419 {
420 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
421 }
422
d_is_whiteout(const struct dentry * dentry)423 static inline bool d_is_whiteout(const struct dentry *dentry)
424 {
425 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
426 }
427
d_can_lookup(const struct dentry * dentry)428 static inline bool d_can_lookup(const struct dentry *dentry)
429 {
430 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
431 }
432
d_is_autodir(const struct dentry * dentry)433 static inline bool d_is_autodir(const struct dentry *dentry)
434 {
435 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
436 }
437
d_is_dir(const struct dentry * dentry)438 static inline bool d_is_dir(const struct dentry *dentry)
439 {
440 return d_can_lookup(dentry) || d_is_autodir(dentry);
441 }
442
d_is_symlink(const struct dentry * dentry)443 static inline bool d_is_symlink(const struct dentry *dentry)
444 {
445 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
446 }
447
d_is_reg(const struct dentry * dentry)448 static inline bool d_is_reg(const struct dentry *dentry)
449 {
450 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
451 }
452
d_is_special(const struct dentry * dentry)453 static inline bool d_is_special(const struct dentry *dentry)
454 {
455 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
456 }
457
d_is_file(const struct dentry * dentry)458 static inline bool d_is_file(const struct dentry *dentry)
459 {
460 return d_is_reg(dentry) || d_is_special(dentry);
461 }
462
d_is_negative(const struct dentry * dentry)463 static inline bool d_is_negative(const struct dentry *dentry)
464 {
465 // TODO: check d_is_whiteout(dentry) also.
466 return d_is_miss(dentry);
467 }
468
d_flags_negative(unsigned flags)469 static inline bool d_flags_negative(unsigned flags)
470 {
471 return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE;
472 }
473
d_is_positive(const struct dentry * dentry)474 static inline bool d_is_positive(const struct dentry *dentry)
475 {
476 return !d_is_negative(dentry);
477 }
478
479 /**
480 * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
481 * @dentry: The dentry in question
482 *
483 * Returns true if the dentry represents either an absent name or a name that
484 * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent
485 * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
486 * fallthrough marker in an opaque directory.
487 *
488 * Note! (1) This should be used *only* by a filesystem to examine its own
489 * dentries. It should not be used to look at some other filesystem's
490 * dentries. (2) It should also be used in combination with d_inode() to get
491 * the inode. (3) The dentry may have something attached to ->d_lower and the
492 * type field of the flags may be set to something other than miss or whiteout.
493 */
d_really_is_negative(const struct dentry * dentry)494 static inline bool d_really_is_negative(const struct dentry *dentry)
495 {
496 return dentry->d_inode == NULL;
497 }
498
499 /**
500 * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
501 * @dentry: The dentry in question
502 *
503 * Returns true if the dentry represents a name that maps to an inode
504 * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if
505 * that is represented on medium as a 0,0 chardev.
506 *
507 * Note! (1) This should be used *only* by a filesystem to examine its own
508 * dentries. It should not be used to look at some other filesystem's
509 * dentries. (2) It should also be used in combination with d_inode() to get
510 * the inode.
511 */
d_really_is_positive(const struct dentry * dentry)512 static inline bool d_really_is_positive(const struct dentry *dentry)
513 {
514 return dentry->d_inode != NULL;
515 }
516
simple_positive(const struct dentry * dentry)517 static inline int simple_positive(const struct dentry *dentry)
518 {
519 return d_really_is_positive(dentry) && !d_unhashed(dentry);
520 }
521
522 extern int sysctl_vfs_cache_pressure;
523
vfs_pressure_ratio(unsigned long val)524 static inline unsigned long vfs_pressure_ratio(unsigned long val)
525 {
526 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
527 }
528
529 /**
530 * d_inode - Get the actual inode of this dentry
531 * @dentry: The dentry to query
532 *
533 * This is the helper normal filesystems should use to get at their own inodes
534 * in their own dentries and ignore the layering superimposed upon them.
535 */
d_inode(const struct dentry * dentry)536 static inline struct inode *d_inode(const struct dentry *dentry)
537 {
538 return dentry->d_inode;
539 }
540
541 /**
542 * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE()
543 * @dentry: The dentry to query
544 *
545 * This is the helper normal filesystems should use to get at their own inodes
546 * in their own dentries and ignore the layering superimposed upon them.
547 */
d_inode_rcu(const struct dentry * dentry)548 static inline struct inode *d_inode_rcu(const struct dentry *dentry)
549 {
550 return READ_ONCE(dentry->d_inode);
551 }
552
553 /**
554 * d_backing_inode - Get upper or lower inode we should be using
555 * @upper: The upper layer
556 *
557 * This is the helper that should be used to get at the inode that will be used
558 * if this dentry were to be opened as a file. The inode may be on the upper
559 * dentry or it may be on a lower dentry pinned by the upper.
560 *
561 * Normal filesystems should not use this to access their own inodes.
562 */
d_backing_inode(const struct dentry * upper)563 static inline struct inode *d_backing_inode(const struct dentry *upper)
564 {
565 struct inode *inode = upper->d_inode;
566
567 return inode;
568 }
569
570 /**
571 * d_real - Return the real dentry
572 * @dentry: the dentry to query
573 * @type: the type of real dentry (data or metadata)
574 *
575 * If dentry is on a union/overlay, then return the underlying, real dentry.
576 * Otherwise return the dentry itself.
577 *
578 * See also: Documentation/filesystems/vfs.rst
579 */
d_real(struct dentry * dentry,enum d_real_type type)580 static inline struct dentry *d_real(struct dentry *dentry, enum d_real_type type)
581 {
582 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
583 return dentry->d_op->d_real(dentry, type);
584 else
585 return dentry;
586 }
587
588 /**
589 * d_real_inode - Return the real inode hosting the data
590 * @dentry: The dentry to query
591 *
592 * If dentry is on a union/overlay, then return the underlying, real inode.
593 * Otherwise return d_inode().
594 */
d_real_inode(const struct dentry * dentry)595 static inline struct inode *d_real_inode(const struct dentry *dentry)
596 {
597 /* This usage of d_real() results in const dentry */
598 return d_inode(d_real((struct dentry *) dentry, D_REAL_DATA));
599 }
600
601 struct name_snapshot {
602 struct qstr name;
603 unsigned char inline_name[DNAME_INLINE_LEN];
604 };
605 void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
606 void release_dentry_name_snapshot(struct name_snapshot *);
607
d_first_child(const struct dentry * dentry)608 static inline struct dentry *d_first_child(const struct dentry *dentry)
609 {
610 return hlist_entry_safe(dentry->d_children.first, struct dentry, d_sib);
611 }
612
d_next_sibling(const struct dentry * dentry)613 static inline struct dentry *d_next_sibling(const struct dentry *dentry)
614 {
615 return hlist_entry_safe(dentry->d_sib.next, struct dentry, d_sib);
616 }
617
618 #endif /* __LINUX_DCACHE_H */
619