1
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
18struct path;
19struct vfsmount;
20
21
22
23
24
25
26
27
28
29
30#define IS_ROOT(x) ((x) == (x)->d_parent)
31
32
33#ifdef __LITTLE_ENDIAN
34 #define HASH_LEN_DECLARE u32 hash; u32 len
35 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
36#else
37 #define HASH_LEN_DECLARE u32 len; u32 hash
38 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
39#endif
40
41
42
43
44
45
46
47
48struct qstr {
49 union {
50 struct {
51 HASH_LEN_DECLARE;
52 };
53 u64 hash_len;
54 };
55 const unsigned char *name;
56};
57
58#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
59
60extern const struct qstr empty_name;
61extern const struct qstr slash_name;
62extern const struct qstr dotdot_name;
63
64struct dentry_stat_t {
65 long nr_dentry;
66 long nr_unused;
67 long age_limit;
68 long want_pages;
69 long nr_negative;
70 long dummy;
71};
72extern struct dentry_stat_t dentry_stat;
73
74
75
76
77
78
79#ifdef CONFIG_64BIT
80# define DNAME_INLINE_LEN 32
81#else
82# ifdef CONFIG_SMP
83# define DNAME_INLINE_LEN 36
84# else
85# define DNAME_INLINE_LEN 40
86# endif
87#endif
88
89#define d_lock d_lockref.lock
90
91struct dentry {
92
93 unsigned int d_flags;
94 seqcount_spinlock_t d_seq;
95 struct hlist_bl_node d_hash;
96 struct dentry *d_parent;
97 struct qstr d_name;
98 struct inode *d_inode;
99
100 unsigned char d_iname[DNAME_INLINE_LEN];
101
102
103 struct lockref d_lockref;
104 const struct dentry_operations *d_op;
105 struct super_block *d_sb;
106 unsigned long d_time;
107 void *d_fsdata;
108
109 union {
110 struct list_head d_lru;
111 wait_queue_head_t *d_wait;
112 };
113 struct list_head d_child;
114 struct list_head d_subdirs;
115
116
117
118 union {
119 struct hlist_node d_alias;
120 struct hlist_bl_node d_in_lookup_hash;
121 struct rcu_head d_rcu;
122 } d_u;
123} __randomize_layout;
124
125
126
127
128
129
130
131enum dentry_d_lock_class
132{
133 DENTRY_D_LOCK_NORMAL,
134 DENTRY_D_LOCK_NESTED
135};
136
137struct dentry_operations {
138 int (*d_revalidate)(struct dentry *, unsigned int);
139 int (*d_weak_revalidate)(struct dentry *, unsigned int);
140 int (*d_hash)(const struct dentry *, struct qstr *);
141 int (*d_compare)(const struct dentry *,
142 unsigned int, const char *, const struct qstr *);
143 int (*d_delete)(const struct dentry *);
144 int (*d_init)(struct dentry *);
145 void (*d_release)(struct dentry *);
146 void (*d_prune)(struct dentry *);
147 void (*d_iput)(struct dentry *, struct inode *);
148 char *(*d_dname)(struct dentry *, char *, int);
149 struct vfsmount *(*d_automount)(struct path *);
150 int (*d_manage)(const struct path *, bool);
151 struct dentry *(*d_real)(struct dentry *, const struct inode *);
152} ____cacheline_aligned;
153
154
155
156
157
158
159
160
161
162
163#define DCACHE_OP_HASH 0x00000001
164#define DCACHE_OP_COMPARE 0x00000002
165#define DCACHE_OP_REVALIDATE 0x00000004
166#define DCACHE_OP_DELETE 0x00000008
167#define DCACHE_OP_PRUNE 0x00000010
168
169#define DCACHE_DISCONNECTED 0x00000020
170
171
172
173
174
175
176
177
178
179
180#define DCACHE_REFERENCED 0x00000040
181
182#define DCACHE_DONTCACHE 0x00000080
183
184#define DCACHE_CANT_MOUNT 0x00000100
185#define DCACHE_GENOCIDE 0x00000200
186#define DCACHE_SHRINK_LIST 0x00000400
187
188#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
189
190#define DCACHE_NFSFS_RENAMED 0x00001000
191
192
193#define DCACHE_COOKIE 0x00002000
194#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
195
196
197#define DCACHE_DENTRY_KILLED 0x00008000
198
199#define DCACHE_MOUNTED 0x00010000
200#define DCACHE_NEED_AUTOMOUNT 0x00020000
201#define DCACHE_MANAGE_TRANSIT 0x00040000
202#define DCACHE_MANAGED_DENTRY \
203 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
204
205#define DCACHE_LRU_LIST 0x00080000
206
207#define DCACHE_ENTRY_TYPE 0x00700000
208#define DCACHE_MISS_TYPE 0x00000000
209#define DCACHE_WHITEOUT_TYPE 0x00100000
210#define DCACHE_DIRECTORY_TYPE 0x00200000
211#define DCACHE_AUTODIR_TYPE 0x00300000
212#define DCACHE_REGULAR_TYPE 0x00400000
213#define DCACHE_SPECIAL_TYPE 0x00500000
214#define DCACHE_SYMLINK_TYPE 0x00600000
215
216#define DCACHE_MAY_FREE 0x00800000
217#define DCACHE_FALLTHRU 0x01000000
218#define DCACHE_NOKEY_NAME 0x02000000
219#define DCACHE_OP_REAL 0x04000000
220
221#define DCACHE_PAR_LOOKUP 0x10000000
222#define DCACHE_DENTRY_CURSOR 0x20000000
223#define DCACHE_NORCU 0x40000000
224
225extern seqlock_t rename_lock;
226
227
228
229
230extern void d_instantiate(struct dentry *, struct inode *);
231extern void d_instantiate_new(struct dentry *, struct inode *);
232extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
233extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *);
234extern void __d_drop(struct dentry *dentry);
235extern void d_drop(struct dentry *dentry);
236extern void d_delete(struct dentry *);
237extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
238
239
240extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
241extern struct dentry * d_alloc_anon(struct super_block *);
242extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
243 wait_queue_head_t *);
244extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
245extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
246extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
247extern struct dentry *d_find_any_alias(struct inode *inode);
248extern struct dentry * d_obtain_alias(struct inode *);
249extern struct dentry * d_obtain_root(struct inode *);
250extern void shrink_dcache_sb(struct super_block *);
251extern void shrink_dcache_parent(struct dentry *);
252extern void shrink_dcache_for_umount(struct super_block *);
253extern void d_invalidate(struct dentry *);
254
255
256extern struct dentry * d_make_root(struct inode *);
257
258
259extern void d_genocide(struct dentry *);
260
261extern void d_tmpfile(struct dentry *, struct inode *);
262
263extern struct dentry *d_find_alias(struct inode *);
264extern void d_prune_aliases(struct inode *);
265
266extern struct dentry *d_find_alias_rcu(struct inode *);
267
268
269extern int path_has_submounts(const struct path *);
270
271
272
273
274extern void d_rehash(struct dentry *);
275
276extern void d_add(struct dentry *, struct inode *);
277
278
279extern void d_move(struct dentry *, struct dentry *);
280extern void d_exchange(struct dentry *, struct dentry *);
281extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
282
283
284extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
285extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
286extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
287extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
288 const struct qstr *name, unsigned *seq);
289
290static inline unsigned d_count(const struct dentry *dentry)
291{
292 return dentry->d_lockref.count;
293}
294
295
296
297
298extern __printf(4, 5)
299char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
300
301extern char *__d_path(const struct path *, const struct path *, char *, int);
302extern char *d_absolute_path(const struct path *, char *, int);
303extern char *d_path(const struct path *, char *, int);
304extern char *dentry_path_raw(const struct dentry *, char *, int);
305extern char *dentry_path(const struct dentry *, char *, int);
306
307
308
309
310
311
312
313
314
315
316
317static inline struct dentry *dget_dlock(struct dentry *dentry)
318{
319 if (dentry)
320 dentry->d_lockref.count++;
321 return dentry;
322}
323
324static inline struct dentry *dget(struct dentry *dentry)
325{
326 if (dentry)
327 lockref_get(&dentry->d_lockref);
328 return dentry;
329}
330
331extern struct dentry *dget_parent(struct dentry *dentry);
332
333
334
335
336
337
338
339
340static inline int d_unhashed(const struct dentry *dentry)
341{
342 return hlist_bl_unhashed(&dentry->d_hash);
343}
344
345static inline int d_unlinked(const struct dentry *dentry)
346{
347 return d_unhashed(dentry) && !IS_ROOT(dentry);
348}
349
350static inline int cant_mount(const struct dentry *dentry)
351{
352 return (dentry->d_flags & DCACHE_CANT_MOUNT);
353}
354
355static inline void dont_mount(struct dentry *dentry)
356{
357 spin_lock(&dentry->d_lock);
358 dentry->d_flags |= DCACHE_CANT_MOUNT;
359 spin_unlock(&dentry->d_lock);
360}
361
362extern void __d_lookup_done(struct dentry *);
363
364static inline int d_in_lookup(const struct dentry *dentry)
365{
366 return dentry->d_flags & DCACHE_PAR_LOOKUP;
367}
368
369static inline void d_lookup_done(struct dentry *dentry)
370{
371 if (unlikely(d_in_lookup(dentry))) {
372 spin_lock(&dentry->d_lock);
373 __d_lookup_done(dentry);
374 spin_unlock(&dentry->d_lock);
375 }
376}
377
378extern void dput(struct dentry *);
379
380static inline bool d_managed(const struct dentry *dentry)
381{
382 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
383}
384
385static inline bool d_mountpoint(const struct dentry *dentry)
386{
387 return dentry->d_flags & DCACHE_MOUNTED;
388}
389
390
391
392
393static inline unsigned __d_entry_type(const struct dentry *dentry)
394{
395 return dentry->d_flags & DCACHE_ENTRY_TYPE;
396}
397
398static inline bool d_is_miss(const struct dentry *dentry)
399{
400 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
401}
402
403static inline bool d_is_whiteout(const struct dentry *dentry)
404{
405 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
406}
407
408static inline bool d_can_lookup(const struct dentry *dentry)
409{
410 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
411}
412
413static inline bool d_is_autodir(const struct dentry *dentry)
414{
415 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
416}
417
418static inline bool d_is_dir(const struct dentry *dentry)
419{
420 return d_can_lookup(dentry) || d_is_autodir(dentry);
421}
422
423static inline bool d_is_symlink(const struct dentry *dentry)
424{
425 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
426}
427
428static inline bool d_is_reg(const struct dentry *dentry)
429{
430 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
431}
432
433static inline bool d_is_special(const struct dentry *dentry)
434{
435 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
436}
437
438static inline bool d_is_file(const struct dentry *dentry)
439{
440 return d_is_reg(dentry) || d_is_special(dentry);
441}
442
443static inline bool d_is_negative(const struct dentry *dentry)
444{
445
446 return d_is_miss(dentry);
447}
448
449static inline bool d_flags_negative(unsigned flags)
450{
451 return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE;
452}
453
454static inline bool d_is_positive(const struct dentry *dentry)
455{
456 return !d_is_negative(dentry);
457}
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474static inline bool d_really_is_negative(const struct dentry *dentry)
475{
476 return dentry->d_inode == NULL;
477}
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492static inline bool d_really_is_positive(const struct dentry *dentry)
493{
494 return dentry->d_inode != NULL;
495}
496
497static inline int simple_positive(const struct dentry *dentry)
498{
499 return d_really_is_positive(dentry) && !d_unhashed(dentry);
500}
501
502extern void d_set_fallthru(struct dentry *dentry);
503
504static inline bool d_is_fallthru(const struct dentry *dentry)
505{
506 return dentry->d_flags & DCACHE_FALLTHRU;
507}
508
509
510extern int sysctl_vfs_cache_pressure;
511
512static inline unsigned long vfs_pressure_ratio(unsigned long val)
513{
514 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
515}
516
517
518
519
520
521
522
523
524static inline struct inode *d_inode(const struct dentry *dentry)
525{
526 return dentry->d_inode;
527}
528
529
530
531
532
533
534
535
536static inline struct inode *d_inode_rcu(const struct dentry *dentry)
537{
538 return READ_ONCE(dentry->d_inode);
539}
540
541
542
543
544
545
546
547
548
549
550
551static inline struct inode *d_backing_inode(const struct dentry *upper)
552{
553 struct inode *inode = upper->d_inode;
554
555 return inode;
556}
557
558
559
560
561
562
563
564
565
566
567
568static inline struct dentry *d_backing_dentry(struct dentry *upper)
569{
570 return upper;
571}
572
573
574
575
576
577
578
579
580
581
582
583static inline struct dentry *d_real(struct dentry *dentry,
584 const struct inode *inode)
585{
586 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
587 return dentry->d_op->d_real(dentry, inode);
588 else
589 return dentry;
590}
591
592
593
594
595
596
597
598
599static inline struct inode *d_real_inode(const struct dentry *dentry)
600{
601
602 return d_backing_inode(d_real((struct dentry *) dentry, NULL));
603}
604
605struct name_snapshot {
606 struct qstr name;
607 unsigned char inline_name[DNAME_INLINE_LEN];
608};
609void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
610void release_dentry_name_snapshot(struct name_snapshot *);
611
612#endif
613