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/rculist.h>
8#include <linux/rculist_bl.h>
9#include <linux/spinlock.h>
10#include <linux/seqlock.h>
11#include <linux/cache.h>
12#include <linux/rcupdate.h>
13#include <linux/lockref.h>
14#include <linux/stringhash.h>
15#include <linux/wait.h>
16
17struct path;
18struct vfsmount;
19
20
21
22
23
24
25
26
27
28
29#define IS_ROOT(x) ((x) == (x)->d_parent)
30
31
32#ifdef __LITTLE_ENDIAN
33 #define HASH_LEN_DECLARE u32 hash; u32 len
34 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
35#else
36 #define HASH_LEN_DECLARE u32 len; u32 hash
37 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
38#endif
39
40
41
42
43
44
45
46
47struct qstr {
48 union {
49 struct {
50 HASH_LEN_DECLARE;
51 };
52 u64 hash_len;
53 };
54 const unsigned char *name;
55};
56
57#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
58
59extern const struct qstr empty_name;
60extern const struct qstr slash_name;
61
62struct dentry_stat_t {
63 long nr_dentry;
64 long nr_unused;
65 long age_limit;
66 long want_pages;
67 long nr_negative;
68 long dummy;
69};
70extern struct dentry_stat_t dentry_stat;
71
72
73
74
75
76
77#ifdef CONFIG_64BIT
78# define DNAME_INLINE_LEN 32
79#else
80# ifdef CONFIG_SMP
81# define DNAME_INLINE_LEN 36
82# else
83# define DNAME_INLINE_LEN 40
84# endif
85#endif
86
87#define d_lock d_lockref.lock
88
89struct dentry {
90
91 unsigned int d_flags;
92 seqcount_spinlock_t d_seq;
93 struct hlist_bl_node d_hash;
94 struct dentry *d_parent;
95 struct qstr d_name;
96 struct inode *d_inode;
97
98 unsigned char d_iname[DNAME_INLINE_LEN];
99
100
101 struct lockref d_lockref;
102 const struct dentry_operations *d_op;
103 struct super_block *d_sb;
104 unsigned long d_time;
105 void *d_fsdata;
106
107 union {
108 struct list_head d_lru;
109 wait_queue_head_t *d_wait;
110 };
111 struct list_head d_child;
112 struct list_head d_subdirs;
113
114
115
116 union {
117 struct hlist_node d_alias;
118 struct hlist_bl_node d_in_lookup_hash;
119 struct rcu_head d_rcu;
120 } d_u;
121} __randomize_layout;
122
123
124
125
126
127
128
129enum dentry_d_lock_class
130{
131 DENTRY_D_LOCK_NORMAL,
132 DENTRY_D_LOCK_NESTED
133};
134
135struct dentry_operations {
136 int (*d_revalidate)(struct dentry *, unsigned int);
137 int (*d_weak_revalidate)(struct dentry *, unsigned int);
138 int (*d_hash)(const struct dentry *, struct qstr *);
139 int (*d_compare)(const struct dentry *,
140 unsigned int, const char *, const struct qstr *);
141 int (*d_delete)(const struct dentry *);
142 int (*d_init)(struct dentry *);
143 void (*d_release)(struct dentry *);
144 void (*d_prune)(struct dentry *);
145 void (*d_iput)(struct dentry *, struct inode *);
146 char *(*d_dname)(struct dentry *, char *, int);
147 struct vfsmount *(*d_automount)(struct path *);
148 int (*d_manage)(const struct path *, bool);
149 struct dentry *(*d_real)(struct dentry *, const struct inode *);
150} ____cacheline_aligned;
151
152
153
154
155
156
157
158
159
160
161#define DCACHE_OP_HASH 0x00000001
162#define DCACHE_OP_COMPARE 0x00000002
163#define DCACHE_OP_REVALIDATE 0x00000004
164#define DCACHE_OP_DELETE 0x00000008
165#define DCACHE_OP_PRUNE 0x00000010
166
167#define DCACHE_DISCONNECTED 0x00000020
168
169
170
171
172
173
174
175
176
177
178#define DCACHE_REFERENCED 0x00000040
179
180#define DCACHE_DONTCACHE 0x00000080
181
182#define DCACHE_CANT_MOUNT 0x00000100
183#define DCACHE_GENOCIDE 0x00000200
184#define DCACHE_SHRINK_LIST 0x00000400
185
186#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
187
188#define DCACHE_NFSFS_RENAMED 0x00001000
189
190
191#define DCACHE_COOKIE 0x00002000
192#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
193
194
195#define DCACHE_DENTRY_KILLED 0x00008000
196
197#define DCACHE_MOUNTED 0x00010000
198#define DCACHE_NEED_AUTOMOUNT 0x00020000
199#define DCACHE_MANAGE_TRANSIT 0x00040000
200#define DCACHE_MANAGED_DENTRY \
201 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
202
203#define DCACHE_LRU_LIST 0x00080000
204
205#define DCACHE_ENTRY_TYPE 0x00700000
206#define DCACHE_MISS_TYPE 0x00000000
207#define DCACHE_WHITEOUT_TYPE 0x00100000
208#define DCACHE_DIRECTORY_TYPE 0x00200000
209#define DCACHE_AUTODIR_TYPE 0x00300000
210#define DCACHE_REGULAR_TYPE 0x00400000
211#define DCACHE_SPECIAL_TYPE 0x00500000
212#define DCACHE_SYMLINK_TYPE 0x00600000
213
214#define DCACHE_MAY_FREE 0x00800000
215#define DCACHE_FALLTHRU 0x01000000
216#define DCACHE_NOKEY_NAME 0x02000000
217#define DCACHE_OP_REAL 0x04000000
218
219#define DCACHE_PAR_LOOKUP 0x10000000
220#define DCACHE_DENTRY_CURSOR 0x20000000
221#define DCACHE_NORCU 0x40000000
222
223extern seqlock_t rename_lock;
224
225
226
227
228extern void d_instantiate(struct dentry *, struct inode *);
229extern void d_instantiate_new(struct dentry *, struct inode *);
230extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
231extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *);
232extern void __d_drop(struct dentry *dentry);
233extern void d_drop(struct dentry *dentry);
234extern void d_delete(struct dentry *);
235extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
236
237
238extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
239extern struct dentry * d_alloc_anon(struct super_block *);
240extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
241 wait_queue_head_t *);
242extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
243extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
244extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
245extern struct dentry *d_find_any_alias(struct inode *inode);
246extern struct dentry * d_obtain_alias(struct inode *);
247extern struct dentry * d_obtain_root(struct inode *);
248extern void shrink_dcache_sb(struct super_block *);
249extern void shrink_dcache_parent(struct dentry *);
250extern void shrink_dcache_for_umount(struct super_block *);
251extern void d_invalidate(struct dentry *);
252
253
254extern struct dentry * d_make_root(struct inode *);
255
256
257extern void d_genocide(struct dentry *);
258
259extern void d_tmpfile(struct dentry *, struct inode *);
260
261extern struct dentry *d_find_alias(struct inode *);
262extern void d_prune_aliases(struct inode *);
263
264
265extern int path_has_submounts(const struct path *);
266
267
268
269
270extern void d_rehash(struct dentry *);
271
272extern void d_add(struct dentry *, struct inode *);
273
274
275extern void d_move(struct dentry *, struct dentry *);
276extern void d_exchange(struct dentry *, struct dentry *);
277extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
278
279
280extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
281extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
282extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
283extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
284 const struct qstr *name, unsigned *seq);
285
286static inline unsigned d_count(const struct dentry *dentry)
287{
288 return dentry->d_lockref.count;
289}
290
291
292
293
294extern __printf(4, 5)
295char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
296
297extern char *__d_path(const struct path *, const struct path *, char *, int);
298extern char *d_absolute_path(const struct path *, char *, int);
299extern char *d_path(const struct path *, char *, int);
300extern char *dentry_path_raw(struct dentry *, char *, int);
301extern char *dentry_path(struct dentry *, char *, int);
302
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310
311
312
313static inline struct dentry *dget_dlock(struct dentry *dentry)
314{
315 if (dentry)
316 dentry->d_lockref.count++;
317 return dentry;
318}
319
320static inline struct dentry *dget(struct dentry *dentry)
321{
322 if (dentry)
323 lockref_get(&dentry->d_lockref);
324 return dentry;
325}
326
327extern struct dentry *dget_parent(struct dentry *dentry);
328
329
330
331
332
333
334
335
336static inline int d_unhashed(const struct dentry *dentry)
337{
338 return hlist_bl_unhashed(&dentry->d_hash);
339}
340
341static inline int d_unlinked(const struct dentry *dentry)
342{
343 return d_unhashed(dentry) && !IS_ROOT(dentry);
344}
345
346static inline int cant_mount(const struct dentry *dentry)
347{
348 return (dentry->d_flags & DCACHE_CANT_MOUNT);
349}
350
351static inline void dont_mount(struct dentry *dentry)
352{
353 spin_lock(&dentry->d_lock);
354 dentry->d_flags |= DCACHE_CANT_MOUNT;
355 spin_unlock(&dentry->d_lock);
356}
357
358extern void __d_lookup_done(struct dentry *);
359
360static inline int d_in_lookup(const struct dentry *dentry)
361{
362 return dentry->d_flags & DCACHE_PAR_LOOKUP;
363}
364
365static inline void d_lookup_done(struct dentry *dentry)
366{
367 if (unlikely(d_in_lookup(dentry))) {
368 spin_lock(&dentry->d_lock);
369 __d_lookup_done(dentry);
370 spin_unlock(&dentry->d_lock);
371 }
372}
373
374extern void dput(struct dentry *);
375
376static inline bool d_managed(const struct dentry *dentry)
377{
378 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
379}
380
381static inline bool d_mountpoint(const struct dentry *dentry)
382{
383 return dentry->d_flags & DCACHE_MOUNTED;
384}
385
386
387
388
389static inline unsigned __d_entry_type(const struct dentry *dentry)
390{
391 return dentry->d_flags & DCACHE_ENTRY_TYPE;
392}
393
394static inline bool d_is_miss(const struct dentry *dentry)
395{
396 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
397}
398
399static inline bool d_is_whiteout(const struct dentry *dentry)
400{
401 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
402}
403
404static inline bool d_can_lookup(const struct dentry *dentry)
405{
406 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
407}
408
409static inline bool d_is_autodir(const struct dentry *dentry)
410{
411 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
412}
413
414static inline bool d_is_dir(const struct dentry *dentry)
415{
416 return d_can_lookup(dentry) || d_is_autodir(dentry);
417}
418
419static inline bool d_is_symlink(const struct dentry *dentry)
420{
421 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
422}
423
424static inline bool d_is_reg(const struct dentry *dentry)
425{
426 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
427}
428
429static inline bool d_is_special(const struct dentry *dentry)
430{
431 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
432}
433
434static inline bool d_is_file(const struct dentry *dentry)
435{
436 return d_is_reg(dentry) || d_is_special(dentry);
437}
438
439static inline bool d_is_negative(const struct dentry *dentry)
440{
441
442 return d_is_miss(dentry);
443}
444
445static inline bool d_flags_negative(unsigned flags)
446{
447 return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE;
448}
449
450static inline bool d_is_positive(const struct dentry *dentry)
451{
452 return !d_is_negative(dentry);
453}
454
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469
470static inline bool d_really_is_negative(const struct dentry *dentry)
471{
472 return dentry->d_inode == NULL;
473}
474
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487
488static inline bool d_really_is_positive(const struct dentry *dentry)
489{
490 return dentry->d_inode != NULL;
491}
492
493static inline int simple_positive(const struct dentry *dentry)
494{
495 return d_really_is_positive(dentry) && !d_unhashed(dentry);
496}
497
498extern void d_set_fallthru(struct dentry *dentry);
499
500static inline bool d_is_fallthru(const struct dentry *dentry)
501{
502 return dentry->d_flags & DCACHE_FALLTHRU;
503}
504
505
506extern int sysctl_vfs_cache_pressure;
507
508static inline unsigned long vfs_pressure_ratio(unsigned long val)
509{
510 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
511}
512
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518
519
520static inline struct inode *d_inode(const struct dentry *dentry)
521{
522 return dentry->d_inode;
523}
524
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531
532static inline struct inode *d_inode_rcu(const struct dentry *dentry)
533{
534 return READ_ONCE(dentry->d_inode);
535}
536
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545
546
547static inline struct inode *d_backing_inode(const struct dentry *upper)
548{
549 struct inode *inode = upper->d_inode;
550
551 return inode;
552}
553
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562
563
564static inline struct dentry *d_backing_dentry(struct dentry *upper)
565{
566 return upper;
567}
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578
579static inline struct dentry *d_real(struct dentry *dentry,
580 const struct inode *inode)
581{
582 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
583 return dentry->d_op->d_real(dentry, inode);
584 else
585 return dentry;
586}
587
588
589
590
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592
593
594
595static inline struct inode *d_real_inode(const struct dentry *dentry)
596{
597
598 return d_backing_inode(d_real((struct dentry *) dentry, NULL));
599}
600
601struct name_snapshot {
602 struct qstr name;
603 unsigned char inline_name[DNAME_INLINE_LEN];
604};
605void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
606void release_dentry_name_snapshot(struct name_snapshot *);
607
608#endif
609