1 |
1275 |
phoenix |
#ifndef __LINUX_DCACHE_H
|
2 |
|
|
#define __LINUX_DCACHE_H
|
3 |
|
|
|
4 |
|
|
#ifdef __KERNEL__
|
5 |
|
|
|
6 |
|
|
#include <asm/atomic.h>
|
7 |
|
|
#include <linux/mount.h>
|
8 |
|
|
#include <linux/kernel.h>
|
9 |
|
|
|
10 |
|
|
/*
|
11 |
|
|
* linux/include/linux/dcache.h
|
12 |
|
|
*
|
13 |
|
|
* Dirent cache data structures
|
14 |
|
|
*
|
15 |
|
|
* (C) Copyright 1997 Thomas Schoebel-Theuer,
|
16 |
|
|
* with heavy changes by Linus Torvalds
|
17 |
|
|
*/
|
18 |
|
|
|
19 |
|
|
#define IS_ROOT(x) ((x) == (x)->d_parent)
|
20 |
|
|
|
21 |
|
|
/*
|
22 |
|
|
* "quick string" -- eases parameter passing, but more importantly
|
23 |
|
|
* saves "metadata" about the string (ie length and the hash).
|
24 |
|
|
*/
|
25 |
|
|
struct qstr {
|
26 |
|
|
const unsigned char * name;
|
27 |
|
|
unsigned int len;
|
28 |
|
|
unsigned int hash;
|
29 |
|
|
};
|
30 |
|
|
|
31 |
|
|
struct dentry_stat_t {
|
32 |
|
|
int nr_dentry;
|
33 |
|
|
int nr_unused;
|
34 |
|
|
int age_limit; /* age in seconds */
|
35 |
|
|
int want_pages; /* pages requested by system */
|
36 |
|
|
int dummy[2];
|
37 |
|
|
};
|
38 |
|
|
extern struct dentry_stat_t dentry_stat;
|
39 |
|
|
|
40 |
|
|
/* Name hashing routines. Initial hash value */
|
41 |
|
|
/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
|
42 |
|
|
#define init_name_hash() 0
|
43 |
|
|
|
44 |
|
|
/* partial hash update function. Assume roughly 4 bits per character */
|
45 |
|
|
static __inline__ unsigned long partial_name_hash(unsigned long c, unsigned long prevhash)
|
46 |
|
|
{
|
47 |
|
|
return (prevhash + (c << 4) + (c >> 4)) * 11;
|
48 |
|
|
}
|
49 |
|
|
|
50 |
|
|
/* Finally: cut down the number of bits to a int value (and try to avoid losing bits) */
|
51 |
|
|
static __inline__ unsigned long end_name_hash(unsigned long hash)
|
52 |
|
|
{
|
53 |
|
|
return (unsigned int) hash;
|
54 |
|
|
}
|
55 |
|
|
|
56 |
|
|
/* Compute the hash for a name string. */
|
57 |
|
|
static __inline__ unsigned int full_name_hash(const unsigned char * name, unsigned int len)
|
58 |
|
|
{
|
59 |
|
|
unsigned long hash = init_name_hash();
|
60 |
|
|
while (len--)
|
61 |
|
|
hash = partial_name_hash(*name++, hash);
|
62 |
|
|
return end_name_hash(hash);
|
63 |
|
|
}
|
64 |
|
|
|
65 |
|
|
#define DNAME_INLINE_LEN 16
|
66 |
|
|
|
67 |
|
|
struct dentry {
|
68 |
|
|
atomic_t d_count;
|
69 |
|
|
unsigned int d_flags;
|
70 |
|
|
struct inode * d_inode; /* Where the name belongs to - NULL is negative */
|
71 |
|
|
struct dentry * d_parent; /* parent directory */
|
72 |
|
|
struct list_head d_hash; /* lookup hash list */
|
73 |
|
|
struct list_head d_lru; /* d_count = 0 LRU list */
|
74 |
|
|
struct list_head d_child; /* child of parent list */
|
75 |
|
|
struct list_head d_subdirs; /* our children */
|
76 |
|
|
struct list_head d_alias; /* inode alias list */
|
77 |
|
|
int d_mounted;
|
78 |
|
|
struct qstr d_name;
|
79 |
|
|
unsigned long d_time; /* used by d_revalidate */
|
80 |
|
|
struct dentry_operations *d_op;
|
81 |
|
|
struct super_block * d_sb; /* The root of the dentry tree */
|
82 |
|
|
unsigned long d_vfs_flags;
|
83 |
|
|
void * d_fsdata; /* fs-specific data */
|
84 |
|
|
unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
|
85 |
|
|
};
|
86 |
|
|
|
87 |
|
|
struct dentry_operations {
|
88 |
|
|
int (*d_revalidate)(struct dentry *, int);
|
89 |
|
|
int (*d_hash) (struct dentry *, struct qstr *);
|
90 |
|
|
int (*d_compare) (struct dentry *, struct qstr *, struct qstr *);
|
91 |
|
|
int (*d_delete)(struct dentry *);
|
92 |
|
|
void (*d_release)(struct dentry *);
|
93 |
|
|
void (*d_iput)(struct dentry *, struct inode *);
|
94 |
|
|
};
|
95 |
|
|
|
96 |
|
|
/* the dentry parameter passed to d_hash and d_compare is the parent
|
97 |
|
|
* directory of the entries to be compared. It is used in case these
|
98 |
|
|
* functions need any directory specific information for determining
|
99 |
|
|
* equivalency classes. Using the dentry itself might not work, as it
|
100 |
|
|
* might be a negative dentry which has no information associated with
|
101 |
|
|
* it */
|
102 |
|
|
|
103 |
|
|
/*
|
104 |
|
|
locking rules:
|
105 |
|
|
big lock dcache_lock may block
|
106 |
|
|
d_revalidate: no no yes
|
107 |
|
|
d_hash no no yes
|
108 |
|
|
d_compare: no yes no
|
109 |
|
|
d_delete: no yes no
|
110 |
|
|
d_release: no no yes
|
111 |
|
|
d_iput: no no yes
|
112 |
|
|
*/
|
113 |
|
|
|
114 |
|
|
/* d_flags entries */
|
115 |
|
|
#define DCACHE_AUTOFS_PENDING 0x0001 /* autofs: "under construction" */
|
116 |
|
|
#define DCACHE_NFSFS_RENAMED 0x0002 /* this dentry has been "silly
|
117 |
|
|
* renamed" and has to be
|
118 |
|
|
* deleted on the last dput()
|
119 |
|
|
*/
|
120 |
|
|
#define DCACHE_NFSD_DISCONNECTED 0x0004 /* This dentry is not currently connected to the
|
121 |
|
|
* dcache tree. Its parent will either be itself,
|
122 |
|
|
* or will have this flag as well.
|
123 |
|
|
* If this dentry points to a directory, then
|
124 |
|
|
* s_nfsd_free_path semaphore will be down
|
125 |
|
|
*/
|
126 |
|
|
#define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */
|
127 |
|
|
|
128 |
|
|
extern spinlock_t dcache_lock;
|
129 |
|
|
|
130 |
|
|
/**
|
131 |
|
|
* d_drop - drop a dentry
|
132 |
|
|
* @dentry: dentry to drop
|
133 |
|
|
*
|
134 |
|
|
* d_drop() unhashes the entry from the parent
|
135 |
|
|
* dentry hashes, so that it won't be found through
|
136 |
|
|
* a VFS lookup any more. Note that this is different
|
137 |
|
|
* from deleting the dentry - d_delete will try to
|
138 |
|
|
* mark the dentry negative if possible, giving a
|
139 |
|
|
* successful _negative_ lookup, while d_drop will
|
140 |
|
|
* just make the cache lookup fail.
|
141 |
|
|
*
|
142 |
|
|
* d_drop() is used mainly for stuff that wants
|
143 |
|
|
* to invalidate a dentry for some reason (NFS
|
144 |
|
|
* timeouts or autofs deletes).
|
145 |
|
|
*/
|
146 |
|
|
|
147 |
|
|
static __inline__ void d_drop(struct dentry * dentry)
|
148 |
|
|
{
|
149 |
|
|
spin_lock(&dcache_lock);
|
150 |
|
|
list_del(&dentry->d_hash);
|
151 |
|
|
INIT_LIST_HEAD(&dentry->d_hash);
|
152 |
|
|
spin_unlock(&dcache_lock);
|
153 |
|
|
}
|
154 |
|
|
|
155 |
|
|
static __inline__ int dname_external(struct dentry *d)
|
156 |
|
|
{
|
157 |
|
|
return d->d_name.name != d->d_iname;
|
158 |
|
|
}
|
159 |
|
|
|
160 |
|
|
/*
|
161 |
|
|
* These are the low-level FS interfaces to the dcache..
|
162 |
|
|
*/
|
163 |
|
|
extern void d_instantiate(struct dentry *, struct inode *);
|
164 |
|
|
extern void d_delete(struct dentry *);
|
165 |
|
|
|
166 |
|
|
/* allocate/de-allocate */
|
167 |
|
|
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
|
168 |
|
|
extern void shrink_dcache_sb(struct super_block *);
|
169 |
|
|
extern void shrink_dcache_parent(struct dentry *);
|
170 |
|
|
extern int d_invalidate(struct dentry *);
|
171 |
|
|
|
172 |
|
|
#define shrink_dcache() prune_dcache(0)
|
173 |
|
|
struct zone_struct;
|
174 |
|
|
/* dcache memory management */
|
175 |
|
|
extern int shrink_dcache_memory(int, unsigned int);
|
176 |
|
|
extern void prune_dcache(int);
|
177 |
|
|
|
178 |
|
|
/* icache memory management (defined in linux/fs/inode.c) */
|
179 |
|
|
extern int shrink_icache_memory(int, int);
|
180 |
|
|
extern void prune_icache(int);
|
181 |
|
|
|
182 |
|
|
/* quota cache memory management (defined in linux/fs/dquot.c) */
|
183 |
|
|
extern int shrink_dqcache_memory(int, unsigned int);
|
184 |
|
|
|
185 |
|
|
/* only used at mount-time */
|
186 |
|
|
extern struct dentry * d_alloc_root(struct inode *);
|
187 |
|
|
|
188 |
|
|
/* <clickety>-<click> the ramfs-type tree */
|
189 |
|
|
extern void d_genocide(struct dentry *);
|
190 |
|
|
|
191 |
|
|
extern struct dentry *d_find_alias(struct inode *);
|
192 |
|
|
extern void d_prune_aliases(struct inode *);
|
193 |
|
|
|
194 |
|
|
/* test whether we have any submounts in a subdir tree */
|
195 |
|
|
extern int have_submounts(struct dentry *);
|
196 |
|
|
|
197 |
|
|
/*
|
198 |
|
|
* This adds the entry to the hash queues.
|
199 |
|
|
*/
|
200 |
|
|
extern void d_rehash(struct dentry *);
|
201 |
|
|
|
202 |
|
|
/**
|
203 |
|
|
* d_add - add dentry to hash queues
|
204 |
|
|
* @entry: dentry to add
|
205 |
|
|
* @inode: The inode to attach to this dentry
|
206 |
|
|
*
|
207 |
|
|
* This adds the entry to the hash queues and initializes @inode.
|
208 |
|
|
* The entry was actually filled in earlier during d_alloc().
|
209 |
|
|
*/
|
210 |
|
|
|
211 |
|
|
static __inline__ void d_add(struct dentry * entry, struct inode * inode)
|
212 |
|
|
{
|
213 |
|
|
d_instantiate(entry, inode);
|
214 |
|
|
d_rehash(entry);
|
215 |
|
|
}
|
216 |
|
|
|
217 |
|
|
/* used for rename() and baskets */
|
218 |
|
|
extern void d_move(struct dentry *, struct dentry *);
|
219 |
|
|
|
220 |
|
|
/* appendix may either be NULL or be used for transname suffixes */
|
221 |
|
|
extern struct dentry * d_lookup(struct dentry *, struct qstr *);
|
222 |
|
|
|
223 |
|
|
/* validate "insecure" dentry pointer */
|
224 |
|
|
extern int d_validate(struct dentry *, struct dentry *);
|
225 |
|
|
|
226 |
|
|
extern char * __d_path(struct dentry *, struct vfsmount *, struct dentry *,
|
227 |
|
|
struct vfsmount *, char *, int);
|
228 |
|
|
|
229 |
|
|
/* Allocation counts.. */
|
230 |
|
|
|
231 |
|
|
/**
|
232 |
|
|
* dget, dget_locked - get a reference to a dentry
|
233 |
|
|
* @dentry: dentry to get a reference to
|
234 |
|
|
*
|
235 |
|
|
* Given a dentry or %NULL pointer increment the reference count
|
236 |
|
|
* if appropriate and return the dentry. A dentry will not be
|
237 |
|
|
* destroyed when it has references. dget() should never be
|
238 |
|
|
* called for dentries with zero reference counter. For these cases
|
239 |
|
|
* (preferably none, functions in dcache.c are sufficient for normal
|
240 |
|
|
* needs and they take necessary precautions) you should hold dcache_lock
|
241 |
|
|
* and call dget_locked() instead of dget().
|
242 |
|
|
*/
|
243 |
|
|
|
244 |
|
|
static __inline__ struct dentry * dget(struct dentry *dentry)
|
245 |
|
|
{
|
246 |
|
|
if (dentry) {
|
247 |
|
|
if (!atomic_read(&dentry->d_count))
|
248 |
|
|
out_of_line_bug();
|
249 |
|
|
atomic_inc(&dentry->d_count);
|
250 |
|
|
}
|
251 |
|
|
return dentry;
|
252 |
|
|
}
|
253 |
|
|
|
254 |
|
|
extern struct dentry * dget_locked(struct dentry *);
|
255 |
|
|
|
256 |
|
|
/**
|
257 |
|
|
* d_unhashed - is dentry hashed
|
258 |
|
|
* @dentry: entry to check
|
259 |
|
|
*
|
260 |
|
|
* Returns true if the dentry passed is not currently hashed.
|
261 |
|
|
*/
|
262 |
|
|
|
263 |
|
|
static __inline__ int d_unhashed(struct dentry *dentry)
|
264 |
|
|
{
|
265 |
|
|
return list_empty(&dentry->d_hash);
|
266 |
|
|
}
|
267 |
|
|
|
268 |
|
|
extern void dput(struct dentry *);
|
269 |
|
|
|
270 |
|
|
static __inline__ int d_mountpoint(struct dentry *dentry)
|
271 |
|
|
{
|
272 |
|
|
return dentry->d_mounted;
|
273 |
|
|
}
|
274 |
|
|
|
275 |
|
|
extern struct vfsmount *lookup_mnt(struct vfsmount *, struct dentry *);
|
276 |
|
|
#endif /* __KERNEL__ */
|
277 |
|
|
|
278 |
|
|
#endif /* __LINUX_DCACHE_H */
|