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