1#ifndef __LINUX_DCACHE_H
2#define __LINUX_DCACHE_H
3
4#include <asm/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
13struct nameidata;
14struct path;
15struct vfsmount;
16
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24
25
26#define IS_ROOT(x) ((x) == (x)->d_parent)
27
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30
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32
33
34
35struct qstr {
36 unsigned int hash;
37 unsigned int len;
38 const unsigned char *name;
39};
40
41struct dentry_stat_t {
42 int nr_dentry;
43 int nr_unused;
44 int age_limit;
45 int want_pages;
46 int dummy[2];
47};
48extern struct dentry_stat_t dentry_stat;
49
50
51
52
53
54static inline int dentry_cmp(const unsigned char *cs, size_t scount,
55 const unsigned char *ct, size_t tcount)
56{
57 int ret;
58 if (scount != tcount)
59 return 1;
60 do {
61 ret = (*cs != *ct);
62 if (ret)
63 break;
64 cs++;
65 ct++;
66 tcount--;
67 } while (tcount);
68 return ret;
69}
70
71
72
73#define init_name_hash() 0
74
75
76static inline unsigned long
77partial_name_hash(unsigned long c, unsigned long prevhash)
78{
79 return (prevhash + (c << 4) + (c >> 4)) * 11;
80}
81
82
83
84
85
86static inline unsigned long end_name_hash(unsigned long hash)
87{
88 return (unsigned int) hash;
89}
90
91
92static inline unsigned int
93full_name_hash(const unsigned char *name, unsigned int len)
94{
95 unsigned long hash = init_name_hash();
96 while (len--)
97 hash = partial_name_hash(*name++, hash);
98 return end_name_hash(hash);
99}
100
101
102
103
104
105
106#ifdef CONFIG_64BIT
107# define DNAME_INLINE_LEN 32
108#else
109# ifdef CONFIG_SMP
110# define DNAME_INLINE_LEN 36
111# else
112# define DNAME_INLINE_LEN 40
113# endif
114#endif
115
116struct dentry {
117
118 unsigned int d_flags;
119 seqcount_t d_seq;
120 struct hlist_bl_node d_hash;
121 struct dentry *d_parent;
122 struct qstr d_name;
123 struct inode *d_inode;
124
125 unsigned char d_iname[DNAME_INLINE_LEN];
126
127
128 unsigned int d_count;
129 spinlock_t d_lock;
130 const struct dentry_operations *d_op;
131 struct super_block *d_sb;
132 unsigned long d_time;
133 void *d_fsdata;
134
135 struct list_head d_lru;
136
137
138
139 union {
140 struct list_head d_child;
141 struct rcu_head d_rcu;
142 } d_u;
143 struct list_head d_subdirs;
144 struct list_head d_alias;
145};
146
147
148
149
150
151
152
153enum dentry_d_lock_class
154{
155 DENTRY_D_LOCK_NORMAL,
156 DENTRY_D_LOCK_NESTED
157};
158
159struct dentry_operations {
160 int (*d_revalidate)(struct dentry *, struct nameidata *);
161 int (*d_hash)(const struct dentry *, const struct inode *,
162 struct qstr *);
163 int (*d_compare)(const struct dentry *, const struct inode *,
164 const struct dentry *, const struct inode *,
165 unsigned int, const char *, const struct qstr *);
166 int (*d_delete)(const struct dentry *);
167 void (*d_release)(struct dentry *);
168 void (*d_iput)(struct dentry *, struct inode *);
169 char *(*d_dname)(struct dentry *, char *, int);
170 struct vfsmount *(*d_automount)(struct path *);
171 int (*d_manage)(struct dentry *, bool);
172} ____cacheline_aligned;
173
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180
181
182
183#define DCACHE_AUTOFS_PENDING 0x0001
184#define DCACHE_NFSFS_RENAMED 0x0002
185
186
187
188#define DCACHE_DISCONNECTED 0x0004
189
190
191
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196
197
198
199#define DCACHE_REFERENCED 0x0008
200#define DCACHE_RCUACCESS 0x0010
201#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020
202
203
204#define DCACHE_COOKIE 0x0040
205#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080
206
207
208#define DCACHE_CANT_MOUNT 0x0100
209#define DCACHE_GENOCIDE 0x0200
210
211#define DCACHE_OP_HASH 0x1000
212#define DCACHE_OP_COMPARE 0x2000
213#define DCACHE_OP_REVALIDATE 0x4000
214#define DCACHE_OP_DELETE 0x8000
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
222extern seqlock_t rename_lock;
223
224static inline int dname_external(struct dentry *dentry)
225{
226 return dentry->d_name.name != dentry->d_iname;
227}
228
229
230
231
232extern void d_instantiate(struct dentry *, struct inode *);
233extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
234extern struct dentry * d_materialise_unique(struct dentry *, struct inode *);
235extern void __d_drop(struct dentry *dentry);
236extern void d_drop(struct dentry *dentry);
237extern void d_delete(struct dentry *);
238extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
239
240
241extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
242extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
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_obtain_alias(struct inode *);
246extern void shrink_dcache_sb(struct super_block *);
247extern void shrink_dcache_parent(struct dentry *);
248extern void shrink_dcache_for_umount(struct super_block *);
249extern int d_invalidate(struct dentry *);
250
251
252extern struct dentry * d_alloc_root(struct inode *);
253
254
255extern void d_genocide(struct dentry *);
256
257extern struct dentry *d_find_alias(struct inode *);
258extern void d_prune_aliases(struct inode *);
259
260
261extern int have_submounts(struct dentry *);
262
263
264
265
266extern void d_rehash(struct dentry *);
267
268
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275
276
277static inline void d_add(struct dentry *entry, struct inode *inode)
278{
279 d_instantiate(entry, inode);
280 d_rehash(entry);
281}
282
283
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285
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287
288
289
290
291static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode)
292{
293 struct dentry *res;
294
295 res = d_instantiate_unique(entry, inode);
296 d_rehash(res != NULL ? res : entry);
297 return res;
298}
299
300extern void dentry_update_name_case(struct dentry *, struct qstr *);
301
302
303extern void d_move(struct dentry *, struct dentry *);
304extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
305
306
307extern struct dentry *d_lookup(struct dentry *, struct qstr *);
308extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
309extern struct dentry *__d_lookup(struct dentry *, struct qstr *);
310extern struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
311 unsigned *seq, struct inode **inode);
312
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320
321
322static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq)
323{
324 int ret = 0;
325
326 assert_spin_locked(&dentry->d_lock);
327 if (!read_seqcount_retry(&dentry->d_seq, seq)) {
328 ret = 1;
329 dentry->d_count++;
330 }
331
332 return ret;
333}
334
335
336extern int d_validate(struct dentry *, struct dentry *);
337
338
339
340
341extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
342
343extern char *__d_path(const struct path *path, struct path *root, char *, int);
344extern char *d_path(const struct path *, char *, int);
345extern char *d_path_with_unreachable(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_count++;
363 return dentry;
364}
365
366static inline struct dentry *dget(struct dentry *dentry)
367{
368 if (dentry) {
369 spin_lock(&dentry->d_lock);
370 dget_dlock(dentry);
371 spin_unlock(&dentry->d_lock);
372 }
373 return dentry;
374}
375
376extern struct dentry *dget_parent(struct dentry *dentry);
377
378
379
380
381
382
383
384
385static inline int d_unhashed(struct dentry *dentry)
386{
387 return hlist_bl_unhashed(&dentry->d_hash);
388}
389
390static inline int d_unlinked(struct dentry *dentry)
391{
392 return d_unhashed(dentry) && !IS_ROOT(dentry);
393}
394
395static inline int cant_mount(struct dentry *dentry)
396{
397 return (dentry->d_flags & DCACHE_CANT_MOUNT);
398}
399
400static inline void dont_mount(struct dentry *dentry)
401{
402 spin_lock(&dentry->d_lock);
403 dentry->d_flags |= DCACHE_CANT_MOUNT;
404 spin_unlock(&dentry->d_lock);
405}
406
407extern void dput(struct dentry *);
408
409static inline bool d_managed(struct dentry *dentry)
410{
411 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
412}
413
414static inline bool d_mountpoint(struct dentry *dentry)
415{
416 return dentry->d_flags & DCACHE_MOUNTED;
417}
418
419extern struct dentry *lookup_create(struct nameidata *nd, int is_dir);
420
421extern int sysctl_vfs_cache_pressure;
422
423#endif
424