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
14struct nameidata;
15struct path;
16struct vfsmount;
17
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20
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24
25
26
27#define IS_ROOT(x) ((x) == (x)->d_parent)
28
29
30#ifdef __LITTLE_ENDIAN
31 #define HASH_LEN_DECLARE u32 hash; u32 len;
32#else
33 #define HASH_LEN_DECLARE u32 len; u32 hash;
34#endif
35
36
37
38
39
40
41
42
43struct qstr {
44 union {
45 struct {
46 HASH_LEN_DECLARE;
47 };
48 u64 hash_len;
49 };
50 const unsigned char *name;
51};
52
53#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
54#define hashlen_hash(hashlen) ((u32) (hashlen))
55#define hashlen_len(hashlen) ((u32)((hashlen) >> 32))
56
57struct dentry_stat_t {
58 int nr_dentry;
59 int nr_unused;
60 int age_limit;
61 int want_pages;
62 int dummy[2];
63};
64extern struct dentry_stat_t dentry_stat;
65
66
67
68#define init_name_hash() 0
69
70
71static inline unsigned long
72partial_name_hash(unsigned long c, unsigned long prevhash)
73{
74 return (prevhash + (c << 4) + (c >> 4)) * 11;
75}
76
77
78
79
80
81static inline unsigned long end_name_hash(unsigned long hash)
82{
83 return (unsigned int) hash;
84}
85
86
87extern unsigned int full_name_hash(const unsigned char *, unsigned int);
88
89
90
91
92
93
94#ifdef CONFIG_64BIT
95# define DNAME_INLINE_LEN 32
96#else
97# ifdef CONFIG_SMP
98# define DNAME_INLINE_LEN 36
99# else
100# define DNAME_INLINE_LEN 40
101# endif
102#endif
103
104#define d_lock d_lockref.lock
105
106struct dentry {
107
108 unsigned int d_flags;
109 seqcount_t d_seq;
110 struct hlist_bl_node d_hash;
111 struct dentry *d_parent;
112 struct qstr d_name;
113 struct inode *d_inode;
114
115 unsigned char d_iname[DNAME_INLINE_LEN];
116
117
118 struct lockref d_lockref;
119 const struct dentry_operations *d_op;
120 struct super_block *d_sb;
121 unsigned long d_time;
122 void *d_fsdata;
123
124 struct list_head d_lru;
125
126
127
128 union {
129 struct list_head d_child;
130 struct rcu_head d_rcu;
131 } d_u;
132 struct list_head d_subdirs;
133 struct hlist_node d_alias;
134};
135
136
137
138
139
140
141
142enum dentry_d_lock_class
143{
144 DENTRY_D_LOCK_NORMAL,
145 DENTRY_D_LOCK_NESTED
146};
147
148struct dentry_operations {
149 int (*d_revalidate)(struct dentry *, unsigned int);
150 int (*d_weak_revalidate)(struct dentry *, unsigned int);
151 int (*d_hash)(const struct dentry *, struct qstr *);
152 int (*d_compare)(const struct dentry *, const struct dentry *,
153 unsigned int, const char *, const struct qstr *);
154 int (*d_delete)(const struct dentry *);
155 void (*d_release)(struct dentry *);
156 void (*d_prune)(struct dentry *);
157 void (*d_iput)(struct dentry *, struct inode *);
158 char *(*d_dname)(struct dentry *, char *, int);
159 struct vfsmount *(*d_automount)(struct path *);
160 RH_KABI_REPLACE(int (*d_manage)(struct dentry *, bool),
161 int (*d_manage)(const struct path *, bool))
162} ____cacheline_aligned;
163
164typedef struct dentry* (*dop_real_t) (struct dentry *, const struct inode *, unsigned int);
165
166struct dentry_operations_wrapper {
167 struct dentry_operations ops;
168 size_t size;
169
170 struct dentry *(*d_real)(struct dentry *, const struct inode *,
171 unsigned int);
172} ____cacheline_aligned;
173
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181
182
183#define DCACHE_OP_HASH 0x0001
184#define DCACHE_OP_COMPARE 0x0002
185#define DCACHE_OP_REVALIDATE 0x0004
186#define DCACHE_OP_DELETE 0x0008
187#define DCACHE_OP_PRUNE 0x0010
188
189#define DCACHE_DISCONNECTED 0x0020
190
191
192
193
194
195
196
197
198
199
200#define DCACHE_REFERENCED 0x0040
201#define DCACHE_RCUACCESS 0x0080
202
203#define DCACHE_CANT_MOUNT 0x0100
204#define DCACHE_GENOCIDE 0x0200
205#define DCACHE_SHRINK_LIST 0x0400
206
207#define DCACHE_OP_WEAK_REVALIDATE 0x0800
208
209#define DCACHE_NFSFS_RENAMED 0x1000
210
211
212#define DCACHE_COOKIE 0x2000
213#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
214
215
216#define DCACHE_MOUNTED 0x10000
217#define DCACHE_NEED_AUTOMOUNT 0x20000
218#define DCACHE_MANAGE_TRANSIT 0x40000
219#define DCACHE_MANAGED_DENTRY \
220 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
221
222#define DCACHE_LRU_LIST 0x80000
223#define DCACHE_DENTRY_KILLED 0x100000
224
225#define DCACHE_ENTRY_TYPE 0x07000000
226#define DCACHE_MISS_TYPE 0x00000000
227#define DCACHE_DIRECTORY_TYPE 0x01000000
228#define DCACHE_AUTODIR_TYPE 0x02000000
229#define DCACHE_SYMLINK_TYPE 0x03000000
230#define DCACHE_FILE_TYPE 0x04000000
231#define DCACHE_OP_REAL 0x08000000
232
233extern seqlock_t rename_lock;
234
235static inline int dname_external(struct dentry *dentry)
236{
237 return dentry->d_name.name != dentry->d_iname;
238}
239
240
241
242
243extern void d_instantiate(struct dentry *, struct inode *);
244extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
245extern struct dentry * d_materialise_unique(struct dentry *, struct inode *);
246extern void __d_drop(struct dentry *dentry);
247extern void d_drop(struct dentry *dentry);
248extern void d_delete(struct dentry *);
249extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
250
251
252extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
253extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
254extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
255extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
256extern struct dentry *d_find_any_alias(struct inode *inode);
257extern struct dentry * d_obtain_alias(struct inode *);
258extern void shrink_dcache_sb(struct super_block *);
259extern void shrink_dcache_parent(struct dentry *);
260extern void shrink_dcache_for_umount(struct super_block *);
261extern int d_invalidate(struct dentry *);
262
263
264extern struct dentry * d_make_root(struct inode *);
265
266
267extern void d_genocide(struct dentry *);
268
269extern void d_tmpfile(struct dentry *, struct inode *);
270
271extern struct dentry *d_find_alias(struct inode *);
272extern void d_prune_aliases(struct inode *);
273
274
275extern int have_submounts(struct dentry *);
276extern int path_has_submounts(const struct path *);
277
278
279
280
281extern void d_rehash(struct dentry *);
282
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290
291
292static inline void d_add(struct dentry *entry, struct inode *inode)
293{
294 d_instantiate(entry, inode);
295 d_rehash(entry);
296}
297
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301
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303
304
305
306static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode)
307{
308 struct dentry *res;
309
310 res = d_instantiate_unique(entry, inode);
311 d_rehash(res != NULL ? res : entry);
312 return res;
313}
314
315extern void dentry_update_name_case(struct dentry *, struct qstr *);
316
317
318extern void d_move(struct dentry *, struct dentry *);
319extern void d_exchange(struct dentry *, struct dentry *);
320extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
321
322
323extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
324extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
325extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
326extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
327 const struct qstr *name, unsigned *seq);
328
329static inline unsigned d_count(const struct dentry *dentry)
330{
331 return dentry->d_lockref.count;
332}
333
334
335extern int d_validate(struct dentry *, struct dentry *);
336
337
338
339
340extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
341extern char *simple_dname(struct dentry *, char *, int);
342
343extern char *__d_path(const struct path *, const struct path *, char *, int);
344extern char *d_absolute_path(const struct path *, char *, int);
345extern char *d_path(const struct path *, char *, int);
346extern char *dentry_path_raw(struct dentry *, char *, int);
347extern char *dentry_path(struct dentry *, char *, int);
348
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357
358
359static inline struct dentry *dget_dlock(struct dentry *dentry)
360{
361 if (dentry)
362 dentry->d_lockref.count++;
363 return dentry;
364}
365
366static inline struct dentry *dget(struct dentry *dentry)
367{
368 if (dentry)
369 lockref_get(&dentry->d_lockref);
370 return dentry;
371}
372
373extern struct dentry *dget_parent(struct dentry *dentry);
374
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378
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380
381
382static inline int d_unhashed(struct dentry *dentry)
383{
384 return hlist_bl_unhashed(&dentry->d_hash);
385}
386
387static inline int d_unlinked(struct dentry *dentry)
388{
389 return d_unhashed(dentry) && !IS_ROOT(dentry);
390}
391
392static inline int cant_mount(struct dentry *dentry)
393{
394 return (dentry->d_flags & DCACHE_CANT_MOUNT);
395}
396
397static inline void dont_mount(struct dentry *dentry)
398{
399 spin_lock(&dentry->d_lock);
400 dentry->d_flags |= DCACHE_CANT_MOUNT;
401 spin_unlock(&dentry->d_lock);
402}
403
404extern void dput(struct dentry *);
405
406static inline bool d_managed(struct dentry *dentry)
407{
408 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
409}
410
411static inline bool d_mountpoint(struct dentry *dentry)
412{
413 return dentry->d_flags & DCACHE_MOUNTED;
414}
415
416
417
418
419static inline void __d_set_type(struct dentry *dentry, unsigned type)
420{
421 dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
422}
423
424static inline void __d_clear_type(struct dentry *dentry)
425{
426 __d_set_type(dentry, DCACHE_MISS_TYPE);
427}
428
429static inline void d_set_type(struct dentry *dentry, unsigned type)
430{
431 spin_lock(&dentry->d_lock);
432 __d_set_type(dentry, type);
433 spin_unlock(&dentry->d_lock);
434}
435
436static inline unsigned __d_entry_type(const struct dentry *dentry)
437{
438 return dentry->d_flags & DCACHE_ENTRY_TYPE;
439}
440
441static inline bool d_can_lookup(const struct dentry *dentry)
442{
443 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
444}
445
446static inline bool d_is_autodir(const struct dentry *dentry)
447{
448 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
449}
450
451static inline bool d_is_dir(const struct dentry *dentry)
452{
453 return d_can_lookup(dentry) || d_is_autodir(dentry);
454}
455
456static inline bool d_is_symlink(const struct dentry *dentry)
457{
458 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
459}
460
461static inline bool d_is_file(const struct dentry *dentry)
462{
463 return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
464}
465
466static inline bool d_is_negative(const struct dentry *dentry)
467{
468 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
469}
470
471static inline bool d_is_positive(const struct dentry *dentry)
472{
473 return !d_is_negative(dentry);
474}
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490
491static inline bool d_really_is_negative(const struct dentry *dentry)
492{
493 return dentry->d_inode == NULL;
494}
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508
509static inline bool d_really_is_positive(const struct dentry *dentry)
510{
511 return dentry->d_inode != NULL;
512}
513
514extern int sysctl_vfs_cache_pressure;
515
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524static inline struct inode *d_inode(const struct dentry *dentry)
525{
526 return dentry->d_inode;
527}
528
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535
536static inline struct inode *d_inode_rcu(const struct dentry *dentry)
537{
538 return ACCESS_ONCE(dentry->d_inode);
539}
540
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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
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567
568static inline struct dentry *d_backing_dentry(struct dentry *upper)
569{
570 return upper;
571}
572
573struct name_snapshot {
574 const char *name;
575 char inline_name[DNAME_INLINE_LEN];
576};
577void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
578void release_dentry_name_snapshot(struct name_snapshot *);
579
580#endif
581