]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | #ifndef __LINUX_DCACHE_H |
2 | #define __LINUX_DCACHE_H | |
3 | ||
1da177e4 LT |
4 | #include <asm/atomic.h> |
5 | #include <linux/list.h> | |
82524746 | 6 | #include <linux/rculist.h> |
1da177e4 | 7 | #include <linux/spinlock.h> |
31e6b01f | 8 | #include <linux/seqlock.h> |
1da177e4 LT |
9 | #include <linux/cache.h> |
10 | #include <linux/rcupdate.h> | |
1da177e4 LT |
11 | |
12 | struct nameidata; | |
cf28b486 | 13 | struct path; |
1da177e4 LT |
14 | struct vfsmount; |
15 | ||
16 | /* | |
17 | * linux/include/linux/dcache.h | |
18 | * | |
19 | * Dirent cache data structures | |
20 | * | |
21 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
22 | * with heavy changes by Linus Torvalds | |
23 | */ | |
24 | ||
25 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
26 | ||
27 | /* | |
28 | * "quick string" -- eases parameter passing, but more importantly | |
29 | * saves "metadata" about the string (ie length and the hash). | |
30 | * | |
31 | * hash comes first so it snuggles against d_parent in the | |
32 | * dentry. | |
33 | */ | |
34 | struct qstr { | |
35 | unsigned int hash; | |
36 | unsigned int len; | |
37 | const unsigned char *name; | |
38 | }; | |
39 | ||
40 | struct dentry_stat_t { | |
41 | int nr_dentry; | |
42 | int nr_unused; | |
43 | int age_limit; /* age in seconds */ | |
44 | int want_pages; /* pages requested by system */ | |
45 | int dummy[2]; | |
46 | }; | |
47 | extern struct dentry_stat_t dentry_stat; | |
48 | ||
49 | /* Name hashing routines. Initial hash value */ | |
50 | /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ | |
51 | #define init_name_hash() 0 | |
52 | ||
53 | /* partial hash update function. Assume roughly 4 bits per character */ | |
54 | static inline unsigned long | |
55 | partial_name_hash(unsigned long c, unsigned long prevhash) | |
56 | { | |
57 | return (prevhash + (c << 4) + (c >> 4)) * 11; | |
58 | } | |
59 | ||
60 | /* | |
61 | * Finally: cut down the number of bits to a int value (and try to avoid | |
62 | * losing bits) | |
63 | */ | |
64 | static inline unsigned long end_name_hash(unsigned long hash) | |
65 | { | |
66 | return (unsigned int) hash; | |
67 | } | |
68 | ||
69 | /* Compute the hash for a name string. */ | |
70 | static inline unsigned int | |
71 | full_name_hash(const unsigned char *name, unsigned int len) | |
72 | { | |
73 | unsigned long hash = init_name_hash(); | |
74 | while (len--) | |
75 | hash = partial_name_hash(*name++, hash); | |
76 | return end_name_hash(hash); | |
77 | } | |
78 | ||
c2452f32 NP |
79 | /* |
80 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
81 | * give reasonable cacheline footprint with larger lines without the | |
82 | * large memory footprint increase). | |
83 | */ | |
84 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 85 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 86 | #else |
44a7d7a8 NP |
87 | # ifdef CONFIG_SMP |
88 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
89 | # else | |
90 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
91 | # endif | |
c2452f32 | 92 | #endif |
1da177e4 LT |
93 | |
94 | struct dentry { | |
44a7d7a8 | 95 | /* RCU lookup touched fields */ |
1da177e4 | 96 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 97 | seqcount_t d_seq; /* per dentry seqlock */ |
3f4bb1f4 | 98 | struct hlist_node d_hash; /* lookup hash list */ |
1da177e4 LT |
99 | struct dentry *d_parent; /* parent directory */ |
100 | struct qstr d_name; | |
44a7d7a8 NP |
101 | struct inode *d_inode; /* Where the name belongs to - NULL is |
102 | * negative */ | |
103 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
104 | ||
105 | /* Ref lookup also touches following */ | |
106 | unsigned int d_count; /* protected by d_lock */ | |
107 | spinlock_t d_lock; /* per dentry lock */ | |
108 | const struct dentry_operations *d_op; | |
109 | struct super_block *d_sb; /* The root of the dentry tree */ | |
110 | unsigned long d_time; /* used by d_revalidate */ | |
111 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 LT |
112 | |
113 | struct list_head d_lru; /* LRU list */ | |
5160ee6f ED |
114 | /* |
115 | * d_child and d_rcu can share memory | |
116 | */ | |
117 | union { | |
118 | struct list_head d_child; /* child of parent list */ | |
119 | struct rcu_head d_rcu; | |
120 | } d_u; | |
1da177e4 LT |
121 | struct list_head d_subdirs; /* our children */ |
122 | struct list_head d_alias; /* inode alias list */ | |
1da177e4 LT |
123 | }; |
124 | ||
a90b9c05 IM |
125 | /* |
126 | * dentry->d_lock spinlock nesting subclasses: | |
127 | * | |
128 | * 0: normal | |
129 | * 1: nested | |
130 | */ | |
131 | enum dentry_d_lock_class | |
132 | { | |
133 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
134 | DENTRY_D_LOCK_NESTED | |
135 | }; | |
136 | ||
1da177e4 LT |
137 | struct dentry_operations { |
138 | int (*d_revalidate)(struct dentry *, struct nameidata *); | |
b1e6a015 NP |
139 | int (*d_hash)(const struct dentry *, const struct inode *, |
140 | struct qstr *); | |
621e155a NP |
141 | int (*d_compare)(const struct dentry *, const struct inode *, |
142 | const struct dentry *, const struct inode *, | |
143 | unsigned int, const char *, const struct qstr *); | |
fe15ce44 | 144 | int (*d_delete)(const struct dentry *); |
1da177e4 LT |
145 | void (*d_release)(struct dentry *); |
146 | void (*d_iput)(struct dentry *, struct inode *); | |
c23fbb6b | 147 | char *(*d_dname)(struct dentry *, char *, int); |
44a7d7a8 | 148 | } ____cacheline_aligned; |
1da177e4 | 149 | |
5eef7fa9 NP |
150 | /* |
151 | * Locking rules for dentry_operations callbacks are to be found in | |
152 | * Documentation/filesystems/Locking. Keep it updated! | |
153 | * | |
621e155a NP |
154 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
155 | * Keep it updated too! | |
1da177e4 LT |
156 | */ |
157 | ||
158 | /* d_flags entries */ | |
159 | #define DCACHE_AUTOFS_PENDING 0x0001 /* autofs: "under construction" */ | |
5f57cbcc NP |
160 | #define DCACHE_NFSFS_RENAMED 0x0002 |
161 | /* this dentry has been "silly renamed" and has to be deleted on the last | |
162 | * dput() */ | |
163 | ||
164 | #define DCACHE_DISCONNECTED 0x0004 | |
165 | /* This dentry is possibly not currently connected to the dcache tree, in | |
166 | * which case its parent will either be itself, or will have this flag as | |
167 | * well. nfsd will not use a dentry with this bit set, but will first | |
168 | * endeavour to clear the bit either by discovering that it is connected, | |
169 | * or by performing lookup operations. Any filesystem which supports | |
170 | * nfsd_operations MUST have a lookup function which, if it finds a | |
171 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
172 | * dentry into place and return that dentry rather than the passed one, | |
173 | * typically using d_splice_alias. */ | |
1da177e4 LT |
174 | |
175 | #define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */ | |
176 | #define DCACHE_UNHASHED 0x0010 | |
5f57cbcc NP |
177 | #define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 |
178 | /* Parent inode is watched by inotify */ | |
c32ccd87 | 179 | |
c2452f32 | 180 | #define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */ |
5f57cbcc NP |
181 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 |
182 | /* Parent inode is watched by some fsnotify listener */ | |
c28f7e56 | 183 | |
d83c49f3 | 184 | #define DCACHE_CANT_MOUNT 0x0100 |
949854d0 | 185 | #define DCACHE_GENOCIDE 0x0200 |
5f57cbcc NP |
186 | #define DCACHE_MOUNTED 0x0400 /* is a mountpoint */ |
187 | ||
fb045adb NP |
188 | #define DCACHE_OP_HASH 0x1000 |
189 | #define DCACHE_OP_COMPARE 0x2000 | |
190 | #define DCACHE_OP_REVALIDATE 0x4000 | |
191 | #define DCACHE_OP_DELETE 0x8000 | |
192 | ||
b23fb0a6 | 193 | extern spinlock_t dcache_inode_lock; |
74c3cbe3 | 194 | extern seqlock_t rename_lock; |
1da177e4 | 195 | |
1da177e4 LT |
196 | static inline int dname_external(struct dentry *dentry) |
197 | { | |
198 | return dentry->d_name.name != dentry->d_iname; | |
199 | } | |
200 | ||
201 | /* | |
202 | * These are the low-level FS interfaces to the dcache.. | |
203 | */ | |
204 | extern void d_instantiate(struct dentry *, struct inode *); | |
205 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
770bfad8 | 206 | extern struct dentry * d_materialise_unique(struct dentry *, struct inode *); |
789680d1 NP |
207 | extern void __d_drop(struct dentry *dentry); |
208 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 209 | extern void d_delete(struct dentry *); |
fb045adb | 210 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
211 | |
212 | /* allocate/de-allocate */ | |
213 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
1da177e4 | 214 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 215 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
4ea3ada2 | 216 | extern struct dentry * d_obtain_alias(struct inode *); |
1da177e4 LT |
217 | extern void shrink_dcache_sb(struct super_block *); |
218 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 219 | extern void shrink_dcache_for_umount(struct super_block *); |
1da177e4 LT |
220 | extern int d_invalidate(struct dentry *); |
221 | ||
222 | /* only used at mount-time */ | |
223 | extern struct dentry * d_alloc_root(struct inode *); | |
224 | ||
225 | /* <clickety>-<click> the ramfs-type tree */ | |
226 | extern void d_genocide(struct dentry *); | |
227 | ||
228 | extern struct dentry *d_find_alias(struct inode *); | |
229 | extern void d_prune_aliases(struct inode *); | |
230 | ||
231 | /* test whether we have any submounts in a subdir tree */ | |
232 | extern int have_submounts(struct dentry *); | |
233 | ||
234 | /* | |
235 | * This adds the entry to the hash queues. | |
236 | */ | |
237 | extern void d_rehash(struct dentry *); | |
238 | ||
239 | /** | |
240 | * d_add - add dentry to hash queues | |
241 | * @entry: dentry to add | |
242 | * @inode: The inode to attach to this dentry | |
243 | * | |
244 | * This adds the entry to the hash queues and initializes @inode. | |
245 | * The entry was actually filled in earlier during d_alloc(). | |
246 | */ | |
247 | ||
248 | static inline void d_add(struct dentry *entry, struct inode *inode) | |
249 | { | |
250 | d_instantiate(entry, inode); | |
251 | d_rehash(entry); | |
252 | } | |
253 | ||
254 | /** | |
255 | * d_add_unique - add dentry to hash queues without aliasing | |
256 | * @entry: dentry to add | |
257 | * @inode: The inode to attach to this dentry | |
258 | * | |
259 | * This adds the entry to the hash queues and initializes @inode. | |
260 | * The entry was actually filled in earlier during d_alloc(). | |
261 | */ | |
262 | static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode) | |
263 | { | |
264 | struct dentry *res; | |
265 | ||
266 | res = d_instantiate_unique(entry, inode); | |
267 | d_rehash(res != NULL ? res : entry); | |
268 | return res; | |
269 | } | |
270 | ||
fb2d5b86 NP |
271 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
272 | ||
1da177e4 LT |
273 | /* used for rename() and baskets */ |
274 | extern void d_move(struct dentry *, struct dentry *); | |
e2761a11 | 275 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
276 | |
277 | /* appendix may either be NULL or be used for transname suffixes */ | |
31e6b01f NP |
278 | extern struct dentry *d_lookup(struct dentry *, struct qstr *); |
279 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); | |
280 | extern struct dentry *__d_lookup(struct dentry *, struct qstr *); | |
281 | extern struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, | |
282 | unsigned *seq, struct inode **inode); | |
283 | ||
284 | /** | |
285 | * __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok | |
286 | * @dentry: dentry to take a ref on | |
287 | * @seq: seqcount to verify against | |
288 | * @Returns: 0 on failure, else 1. | |
289 | * | |
290 | * __d_rcu_to_refcount operates on a dentry,seq pair that was returned | |
291 | * by __d_lookup_rcu, to get a reference on an rcu-walk dentry. | |
292 | */ | |
293 | static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq) | |
294 | { | |
295 | int ret = 0; | |
296 | ||
297 | assert_spin_locked(&dentry->d_lock); | |
298 | if (!read_seqcount_retry(&dentry->d_seq, seq)) { | |
299 | ret = 1; | |
300 | dentry->d_count++; | |
301 | } | |
302 | ||
303 | return ret; | |
304 | } | |
1da177e4 LT |
305 | |
306 | /* validate "insecure" dentry pointer */ | |
307 | extern int d_validate(struct dentry *, struct dentry *); | |
308 | ||
c23fbb6b ED |
309 | /* |
310 | * helper function for dentry_operations.d_dname() members | |
311 | */ | |
312 | extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
313 | ||
9d1bc601 | 314 | extern char *__d_path(const struct path *path, struct path *root, char *, int); |
20d4fdc1 | 315 | extern char *d_path(const struct path *, char *, int); |
8df9d1a4 | 316 | extern char *d_path_with_unreachable(const struct path *, char *, int); |
ec2447c2 | 317 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 318 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 319 | |
1da177e4 LT |
320 | /* Allocation counts.. */ |
321 | ||
322 | /** | |
dc0474be | 323 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
324 | * @dentry: dentry to get a reference to |
325 | * | |
326 | * Given a dentry or %NULL pointer increment the reference count | |
327 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 328 | * destroyed when it has references. |
1da177e4 | 329 | */ |
b7ab39f6 NP |
330 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
331 | { | |
dc0474be | 332 | if (dentry) |
b7ab39f6 | 333 | dentry->d_count++; |
b7ab39f6 NP |
334 | return dentry; |
335 | } | |
2fd6b7f5 | 336 | |
1da177e4 LT |
337 | static inline struct dentry *dget(struct dentry *dentry) |
338 | { | |
339 | if (dentry) { | |
b7ab39f6 NP |
340 | spin_lock(&dentry->d_lock); |
341 | dget_dlock(dentry); | |
342 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
343 | } |
344 | return dentry; | |
345 | } | |
346 | ||
b7ab39f6 | 347 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
348 | |
349 | /** | |
350 | * d_unhashed - is dentry hashed | |
351 | * @dentry: entry to check | |
352 | * | |
353 | * Returns true if the dentry passed is not currently hashed. | |
354 | */ | |
355 | ||
356 | static inline int d_unhashed(struct dentry *dentry) | |
357 | { | |
358 | return (dentry->d_flags & DCACHE_UNHASHED); | |
359 | } | |
360 | ||
f3da392e AD |
361 | static inline int d_unlinked(struct dentry *dentry) |
362 | { | |
363 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
364 | } | |
365 | ||
d83c49f3 AV |
366 | static inline int cant_mount(struct dentry *dentry) |
367 | { | |
368 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
369 | } | |
370 | ||
371 | static inline void dont_mount(struct dentry *dentry) | |
372 | { | |
373 | spin_lock(&dentry->d_lock); | |
374 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
375 | spin_unlock(&dentry->d_lock); | |
376 | } | |
377 | ||
1da177e4 LT |
378 | extern void dput(struct dentry *); |
379 | ||
380 | static inline int d_mountpoint(struct dentry *dentry) | |
381 | { | |
5f57cbcc | 382 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
383 | } |
384 | ||
1c755af4 | 385 | extern struct vfsmount *lookup_mnt(struct path *); |
1da177e4 LT |
386 | extern struct dentry *lookup_create(struct nameidata *nd, int is_dir); |
387 | ||
388 | extern int sysctl_vfs_cache_pressure; | |
389 | ||
1da177e4 | 390 | #endif /* __LINUX_DCACHE_H */ |