1#ifndef __LINUX_DCACHE_H
2#define __LINUX_DCACHE_H
3
4#include <linux/atomic.h>
5#include <linux/list.h>
6#include <linux/rculist.h>
7#include <linux/rculist_bl.h>
8#include <linux/spinlock.h>
9#include <linux/seqlock.h>
10#include <linux/cache.h>
11#include <linux/rcupdate.h>
12#include <linux/lockref.h>
13#include <linux/stringhash.h>
14#include <linux/wait.h>
15
16struct path;
17struct vfsmount;
18
19
20
21
22
23
24
25
26
27
28#define IS_ROOT(x) ((x) == (x)->d_parent)
29
30
31#ifdef __LITTLE_ENDIAN
32 #define HASH_LEN_DECLARE u32 hash; u32 len
33 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
34#else
35 #define HASH_LEN_DECLARE u32 len; u32 hash
36 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
37#endif
38
39
40
41
42
43
44
45
46struct qstr {
47 union {
48 struct {
49 HASH_LEN_DECLARE;
50 };
51 u64 hash_len;
52 };
53 const unsigned char *name;
54};
55
56#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
57
58struct dentry_stat_t {
59 long nr_dentry;
60 long nr_unused;
61 long age_limit;
62 long want_pages;
63 long dummy[2];
64};
65extern struct dentry_stat_t dentry_stat;
66
67
68
69
70
71
72#ifdef CONFIG_64BIT
73# define DNAME_INLINE_LEN 32
74#else
75# ifdef CONFIG_SMP
76# define DNAME_INLINE_LEN 36
77# else
78# define DNAME_INLINE_LEN 40
79# endif
80#endif
81
82#define d_lock d_lockref.lock
83
84struct dentry {
85
86 unsigned int d_flags;
87 seqcount_t d_seq;
88 struct hlist_bl_node d_hash;
89 struct dentry *d_parent;
90 struct qstr d_name;
91 struct inode *d_inode;
92
93 unsigned char d_iname[DNAME_INLINE_LEN];
94
95
96 struct lockref d_lockref;
97 const struct dentry_operations *d_op;
98 struct super_block *d_sb;
99 unsigned long d_time;
100 void *d_fsdata;
101
102 union {
103 struct list_head d_lru;
104 wait_queue_head_t *d_wait;
105 };
106 struct list_head d_child;
107 struct list_head d_subdirs;
108
109
110
111 union {
112 struct hlist_node d_alias;
113 struct hlist_bl_node d_in_lookup_hash;
114 struct rcu_head d_rcu;
115 } d_u;
116};
117
118
119
120
121
122
123
124enum dentry_d_lock_class
125{
126 DENTRY_D_LOCK_NORMAL,
127 DENTRY_D_LOCK_NESTED
128};
129
130struct dentry_operations {
131 int (*d_revalidate)(struct dentry *, unsigned int);
132 int (*d_weak_revalidate)(struct dentry *, unsigned int);
133 int (*d_hash)(const struct dentry *, struct qstr *);
134 int (*d_compare)(const struct dentry *,
135 unsigned int, const char *, const struct qstr *);
136 int (*d_delete)(const struct dentry *);
137 int (*d_init)(struct dentry *);
138 void (*d_release)(struct dentry *);
139 void (*d_prune)(struct dentry *);
140 void (*d_iput)(struct dentry *, struct inode *);
141 char *(*d_dname)(struct dentry *, char *, int);
142 struct vfsmount *(*d_automount)(struct path *);
143 int (*d_manage)(const struct path *, bool);
144 struct dentry *(*d_real)(struct dentry *, const struct inode *,
145 unsigned int);
146} ____cacheline_aligned;
147
148
149
150
151
152
153
154
155
156
157#define DCACHE_OP_HASH 0x00000001
158#define DCACHE_OP_COMPARE 0x00000002
159#define DCACHE_OP_REVALIDATE 0x00000004
160#define DCACHE_OP_DELETE 0x00000008
161#define DCACHE_OP_PRUNE 0x00000010
162
163#define DCACHE_DISCONNECTED 0x00000020
164
165
166
167
168
169
170
171
172
173
174#define DCACHE_REFERENCED 0x00000040
175#define DCACHE_RCUACCESS 0x00000080
176
177#define DCACHE_CANT_MOUNT 0x00000100
178#define DCACHE_GENOCIDE 0x00000200
179#define DCACHE_SHRINK_LIST 0x00000400
180
181#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
182
183#define DCACHE_NFSFS_RENAMED 0x00001000
184
185
186#define DCACHE_COOKIE 0x00002000
187#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
188
189
190#define DCACHE_DENTRY_KILLED 0x00008000
191
192#define DCACHE_MOUNTED 0x00010000
193#define DCACHE_NEED_AUTOMOUNT 0x00020000
194#define DCACHE_MANAGE_TRANSIT 0x00040000
195#define DCACHE_MANAGED_DENTRY \
196 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
197
198#define DCACHE_LRU_LIST 0x00080000
199
200#define DCACHE_ENTRY_TYPE 0x00700000
201#define DCACHE_MISS_TYPE 0x00000000
202#define DCACHE_WHITEOUT_TYPE 0x00100000
203#define DCACHE_DIRECTORY_TYPE 0x00200000
204#define DCACHE_AUTODIR_TYPE 0x00300000
205#define DCACHE_REGULAR_TYPE 0x00400000
206#define DCACHE_SPECIAL_TYPE 0x00500000
207#define DCACHE_SYMLINK_TYPE 0x00600000
208
209#define DCACHE_MAY_FREE 0x00800000
210#define DCACHE_FALLTHRU 0x01000000
211#define DCACHE_ENCRYPTED_WITH_KEY 0x02000000
212#define DCACHE_OP_REAL 0x04000000
213
214#define DCACHE_PAR_LOOKUP 0x10000000
215#define DCACHE_DENTRY_CURSOR 0x20000000
216
217extern seqlock_t rename_lock;
218
219
220
221
222extern void d_instantiate(struct dentry *, struct inode *);
223extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
224extern int d_instantiate_no_diralias(struct dentry *, struct inode *);
225extern void __d_drop(struct dentry *dentry);
226extern void d_drop(struct dentry *dentry);
227extern void d_delete(struct dentry *);
228extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
229
230
231extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
232extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
233extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
234 wait_queue_head_t *);
235extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
236extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
237extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
238extern struct dentry *d_find_any_alias(struct inode *inode);
239extern struct dentry * d_obtain_alias(struct inode *);
240extern struct dentry * d_obtain_root(struct inode *);
241extern void shrink_dcache_sb(struct super_block *);
242extern void shrink_dcache_parent(struct dentry *);
243extern void shrink_dcache_for_umount(struct super_block *);
244extern void d_invalidate(struct dentry *);
245
246
247extern struct dentry * d_make_root(struct inode *);
248
249
250extern void d_genocide(struct dentry *);
251
252extern void d_tmpfile(struct dentry *, struct inode *);
253
254extern struct dentry *d_find_alias(struct inode *);
255extern void d_prune_aliases(struct inode *);
256
257
258extern int path_has_submounts(const struct path *);
259
260
261
262
263extern void d_rehash(struct dentry *);
264
265extern void d_add(struct dentry *, struct inode *);
266
267extern void dentry_update_name_case(struct dentry *, const struct qstr *);
268
269
270extern void d_move(struct dentry *, struct dentry *);
271extern void d_exchange(struct dentry *, struct dentry *);
272extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
273
274
275extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
276extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
277extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
278extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
279 const struct qstr *name, unsigned *seq);
280
281static inline unsigned d_count(const struct dentry *dentry)
282{
283 return dentry->d_lockref.count;
284}
285
286
287
288
289extern __printf(4, 5)
290char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
291extern char *simple_dname(struct dentry *, char *, int);
292
293extern char *__d_path(const struct path *, const struct path *, char *, int);
294extern char *d_absolute_path(const struct path *, char *, int);
295extern char *d_path(const struct path *, char *, int);
296extern char *dentry_path_raw(struct dentry *, char *, int);
297extern char *dentry_path(struct dentry *, char *, int);
298
299
300
301
302
303
304
305
306
307
308
309static inline struct dentry *dget_dlock(struct dentry *dentry)
310{
311 if (dentry)
312 dentry->d_lockref.count++;
313 return dentry;
314}
315
316static inline struct dentry *dget(struct dentry *dentry)
317{
318 if (dentry)
319 lockref_get(&dentry->d_lockref);
320 return dentry;
321}
322
323extern struct dentry *dget_parent(struct dentry *dentry);
324
325
326
327
328
329
330
331
332static inline int d_unhashed(const struct dentry *dentry)
333{
334 return hlist_bl_unhashed(&dentry->d_hash);
335}
336
337static inline int d_unlinked(const struct dentry *dentry)
338{
339 return d_unhashed(dentry) && !IS_ROOT(dentry);
340}
341
342static inline int cant_mount(const struct dentry *dentry)
343{
344 return (dentry->d_flags & DCACHE_CANT_MOUNT);
345}
346
347static inline void dont_mount(struct dentry *dentry)
348{
349 spin_lock(&dentry->d_lock);
350 dentry->d_flags |= DCACHE_CANT_MOUNT;
351 spin_unlock(&dentry->d_lock);
352}
353
354extern void __d_lookup_done(struct dentry *);
355
356static inline int d_in_lookup(struct dentry *dentry)
357{
358 return dentry->d_flags & DCACHE_PAR_LOOKUP;
359}
360
361static inline void d_lookup_done(struct dentry *dentry)
362{
363 if (unlikely(d_in_lookup(dentry))) {
364 spin_lock(&dentry->d_lock);
365 __d_lookup_done(dentry);
366 spin_unlock(&dentry->d_lock);
367 }
368}
369
370extern void dput(struct dentry *);
371
372static inline bool d_managed(const struct dentry *dentry)
373{
374 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
375}
376
377static inline bool d_mountpoint(const struct dentry *dentry)
378{
379 return dentry->d_flags & DCACHE_MOUNTED;
380}
381
382
383
384
385static inline unsigned __d_entry_type(const struct dentry *dentry)
386{
387 return dentry->d_flags & DCACHE_ENTRY_TYPE;
388}
389
390static inline bool d_is_miss(const struct dentry *dentry)
391{
392 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
393}
394
395static inline bool d_is_whiteout(const struct dentry *dentry)
396{
397 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
398}
399
400static inline bool d_can_lookup(const struct dentry *dentry)
401{
402 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
403}
404
405static inline bool d_is_autodir(const struct dentry *dentry)
406{
407 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
408}
409
410static inline bool d_is_dir(const struct dentry *dentry)
411{
412 return d_can_lookup(dentry) || d_is_autodir(dentry);
413}
414
415static inline bool d_is_symlink(const struct dentry *dentry)
416{
417 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
418}
419
420static inline bool d_is_reg(const struct dentry *dentry)
421{
422 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
423}
424
425static inline bool d_is_special(const struct dentry *dentry)
426{
427 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
428}
429
430static inline bool d_is_file(const struct dentry *dentry)
431{
432 return d_is_reg(dentry) || d_is_special(dentry);
433}
434
435static inline bool d_is_negative(const struct dentry *dentry)
436{
437
438 return d_is_miss(dentry);
439}
440
441static inline bool d_is_positive(const struct dentry *dentry)
442{
443 return !d_is_negative(dentry);
444}
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461static inline bool d_really_is_negative(const struct dentry *dentry)
462{
463 return dentry->d_inode == NULL;
464}
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479static inline bool d_really_is_positive(const struct dentry *dentry)
480{
481 return dentry->d_inode != NULL;
482}
483
484static inline int simple_positive(struct dentry *dentry)
485{
486 return d_really_is_positive(dentry) && !d_unhashed(dentry);
487}
488
489extern void d_set_fallthru(struct dentry *dentry);
490
491static inline bool d_is_fallthru(const struct dentry *dentry)
492{
493 return dentry->d_flags & DCACHE_FALLTHRU;
494}
495
496
497extern int sysctl_vfs_cache_pressure;
498
499static inline unsigned long vfs_pressure_ratio(unsigned long val)
500{
501 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
502}
503
504
505
506
507
508
509
510
511static inline struct inode *d_inode(const struct dentry *dentry)
512{
513 return dentry->d_inode;
514}
515
516
517
518
519
520
521
522
523static inline struct inode *d_inode_rcu(const struct dentry *dentry)
524{
525 return ACCESS_ONCE(dentry->d_inode);
526}
527
528
529
530
531
532
533
534
535
536
537
538static inline struct inode *d_backing_inode(const struct dentry *upper)
539{
540 struct inode *inode = upper->d_inode;
541
542 return inode;
543}
544
545
546
547
548
549
550
551
552
553
554
555static inline struct dentry *d_backing_dentry(struct dentry *upper)
556{
557 return upper;
558}
559
560
561
562
563
564
565
566
567
568
569
570
571static inline struct dentry *d_real(struct dentry *dentry,
572 const struct inode *inode,
573 unsigned int flags)
574{
575 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
576 return dentry->d_op->d_real(dentry, inode, flags);
577 else
578 return dentry;
579}
580
581
582
583
584
585
586
587
588static inline struct inode *d_real_inode(const struct dentry *dentry)
589{
590
591 return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0));
592}
593
594
595#endif
596