Commit | Line | Data |
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1da177e4 LT |
1 | #ifndef __LINUX_DCACHE_H |
2 | #define __LINUX_DCACHE_H | |
3 | ||
60063497 | 4 | #include <linux/atomic.h> |
1da177e4 | 5 | #include <linux/list.h> |
82524746 | 6 | #include <linux/rculist.h> |
ceb5bdc2 | 7 | #include <linux/rculist_bl.h> |
1da177e4 | 8 | #include <linux/spinlock.h> |
31e6b01f | 9 | #include <linux/seqlock.h> |
1da177e4 LT |
10 | #include <linux/cache.h> |
11 | #include <linux/rcupdate.h> | |
98474236 | 12 | #include <linux/lockref.h> |
1da177e4 LT |
13 | |
14 | struct nameidata; | |
cf28b486 | 15 | struct path; |
1da177e4 LT |
16 | struct vfsmount; |
17 | ||
18 | /* | |
19 | * linux/include/linux/dcache.h | |
20 | * | |
21 | * Dirent cache data structures | |
22 | * | |
23 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
24 | * with heavy changes by Linus Torvalds | |
25 | */ | |
26 | ||
27 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
28 | ||
26fe5750 LT |
29 | /* The hash is always the low bits of hash_len */ |
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 | ||
1da177e4 LT |
36 | /* |
37 | * "quick string" -- eases parameter passing, but more importantly | |
38 | * saves "metadata" about the string (ie length and the hash). | |
39 | * | |
40 | * hash comes first so it snuggles against d_parent in the | |
41 | * dentry. | |
42 | */ | |
43 | struct qstr { | |
26fe5750 LT |
44 | union { |
45 | struct { | |
46 | HASH_LEN_DECLARE; | |
47 | }; | |
48 | u64 hash_len; | |
49 | }; | |
1da177e4 LT |
50 | const unsigned char *name; |
51 | }; | |
52 | ||
26fe5750 LT |
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 | ||
1da177e4 | 57 | struct dentry_stat_t { |
3942c07c GC |
58 | long nr_dentry; |
59 | long nr_unused; | |
60 | long age_limit; /* age in seconds */ | |
61 | long want_pages; /* pages requested by system */ | |
62 | long dummy[2]; | |
1da177e4 LT |
63 | }; |
64 | extern struct dentry_stat_t dentry_stat; | |
65 | ||
66 | /* Name hashing routines. Initial hash value */ | |
67 | /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ | |
68 | #define init_name_hash() 0 | |
69 | ||
70 | /* partial hash update function. Assume roughly 4 bits per character */ | |
71 | static inline unsigned long | |
72 | partial_name_hash(unsigned long c, unsigned long prevhash) | |
73 | { | |
74 | return (prevhash + (c << 4) + (c >> 4)) * 11; | |
75 | } | |
76 | ||
77 | /* | |
78 | * Finally: cut down the number of bits to a int value (and try to avoid | |
79 | * losing bits) | |
80 | */ | |
81 | static inline unsigned long end_name_hash(unsigned long hash) | |
82 | { | |
83 | return (unsigned int) hash; | |
84 | } | |
85 | ||
86 | /* Compute the hash for a name string. */ | |
0145acc2 | 87 | extern unsigned int full_name_hash(const unsigned char *, unsigned int); |
1da177e4 | 88 | |
c2452f32 NP |
89 | /* |
90 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
91 | * give reasonable cacheline footprint with larger lines without the | |
92 | * large memory footprint increase). | |
93 | */ | |
94 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 95 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 96 | #else |
44a7d7a8 NP |
97 | # ifdef CONFIG_SMP |
98 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
99 | # else | |
100 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
101 | # endif | |
c2452f32 | 102 | #endif |
1da177e4 | 103 | |
98474236 WL |
104 | #define d_lock d_lockref.lock |
105 | ||
1da177e4 | 106 | struct dentry { |
44a7d7a8 | 107 | /* RCU lookup touched fields */ |
1da177e4 | 108 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 109 | seqcount_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 110 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
111 | struct dentry *d_parent; /* parent directory */ |
112 | struct qstr d_name; | |
44a7d7a8 NP |
113 | struct inode *d_inode; /* Where the name belongs to - NULL is |
114 | * negative */ | |
115 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
116 | ||
117 | /* Ref lookup also touches following */ | |
98474236 | 118 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
119 | const struct dentry_operations *d_op; |
120 | struct super_block *d_sb; /* The root of the dentry tree */ | |
121 | unsigned long d_time; /* used by d_revalidate */ | |
122 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 LT |
123 | |
124 | struct list_head d_lru; /* LRU list */ | |
5160ee6f ED |
125 | /* |
126 | * d_child and d_rcu can share memory | |
127 | */ | |
128 | union { | |
129 | struct list_head d_child; /* child of parent list */ | |
130 | struct rcu_head d_rcu; | |
131 | } d_u; | |
1da177e4 | 132 | struct list_head d_subdirs; /* our children */ |
b3d9b7a3 | 133 | struct hlist_node d_alias; /* inode alias list */ |
1da177e4 LT |
134 | }; |
135 | ||
a90b9c05 IM |
136 | /* |
137 | * dentry->d_lock spinlock nesting subclasses: | |
138 | * | |
139 | * 0: normal | |
140 | * 1: nested | |
141 | */ | |
142 | enum dentry_d_lock_class | |
143 | { | |
144 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
145 | DENTRY_D_LOCK_NESTED | |
146 | }; | |
147 | ||
1da177e4 | 148 | struct dentry_operations { |
0b728e19 | 149 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 150 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 LT |
151 | int (*d_hash)(const struct dentry *, struct qstr *); |
152 | int (*d_compare)(const struct dentry *, const struct dentry *, | |
621e155a | 153 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 154 | int (*d_delete)(const struct dentry *); |
1da177e4 | 155 | void (*d_release)(struct dentry *); |
f0023bc6 | 156 | void (*d_prune)(struct dentry *); |
1da177e4 | 157 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 158 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 159 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 160 | int (*d_manage)(struct dentry *, bool); |
44a7d7a8 | 161 | } ____cacheline_aligned; |
1da177e4 | 162 | |
5eef7fa9 NP |
163 | /* |
164 | * Locking rules for dentry_operations callbacks are to be found in | |
165 | * Documentation/filesystems/Locking. Keep it updated! | |
166 | * | |
621e155a NP |
167 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
168 | * Keep it updated too! | |
1da177e4 LT |
169 | */ |
170 | ||
171 | /* d_flags entries */ | |
b18825a7 DH |
172 | #define DCACHE_OP_HASH 0x00000001 |
173 | #define DCACHE_OP_COMPARE 0x00000002 | |
174 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
175 | #define DCACHE_OP_DELETE 0x00000008 | |
176 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 177 | |
b18825a7 | 178 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
179 | /* This dentry is possibly not currently connected to the dcache tree, in |
180 | * which case its parent will either be itself, or will have this flag as | |
181 | * well. nfsd will not use a dentry with this bit set, but will first | |
182 | * endeavour to clear the bit either by discovering that it is connected, | |
183 | * or by performing lookup operations. Any filesystem which supports | |
184 | * nfsd_operations MUST have a lookup function which, if it finds a | |
185 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
186 | * dentry into place and return that dentry rather than the passed one, | |
187 | * typically using d_splice_alias. */ | |
1da177e4 | 188 | |
b18825a7 DH |
189 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
190 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 191 | |
b18825a7 DH |
192 | #define DCACHE_CANT_MOUNT 0x00000100 |
193 | #define DCACHE_GENOCIDE 0x00000200 | |
194 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 195 | |
b18825a7 | 196 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 197 | |
b18825a7 | 198 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
199 | /* this dentry has been "silly renamed" and has to be deleted on the last |
200 | * dput() */ | |
b18825a7 DH |
201 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
202 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 203 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 204 | |
b18825a7 DH |
205 | #define DCACHE_DENTRY_KILLED 0x00008000 |
206 | ||
207 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
208 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
209 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 210 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 211 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 212 | |
b18825a7 DH |
213 | #define DCACHE_LRU_LIST 0x00080000 |
214 | ||
215 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
216 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry */ | |
217 | #define DCACHE_DIRECTORY_TYPE 0x00100000 /* Normal directory */ | |
218 | #define DCACHE_AUTODIR_TYPE 0x00200000 /* Lookupless directory (presumed automount) */ | |
219 | #define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */ | |
220 | #define DCACHE_FILE_TYPE 0x00400000 /* Other file type */ | |
b161dfa6 | 221 | |
74c3cbe3 | 222 | extern seqlock_t rename_lock; |
1da177e4 | 223 | |
f0d3b3de | 224 | static inline int dname_external(const struct dentry *dentry) |
1da177e4 LT |
225 | { |
226 | return dentry->d_name.name != dentry->d_iname; | |
227 | } | |
228 | ||
229 | /* | |
230 | * These are the low-level FS interfaces to the dcache.. | |
231 | */ | |
232 | extern void d_instantiate(struct dentry *, struct inode *); | |
233 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
770bfad8 | 234 | extern struct dentry * d_materialise_unique(struct dentry *, struct inode *); |
b70a80e7 | 235 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
236 | extern void __d_drop(struct dentry *dentry); |
237 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 238 | extern void d_delete(struct dentry *); |
fb045adb | 239 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
240 | |
241 | /* allocate/de-allocate */ | |
242 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 243 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
1da177e4 | 244 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 245 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
46f72b34 | 246 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 247 | extern struct dentry * d_obtain_alias(struct inode *); |
1da177e4 LT |
248 | extern void shrink_dcache_sb(struct super_block *); |
249 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 250 | extern void shrink_dcache_for_umount(struct super_block *); |
1da177e4 LT |
251 | extern int d_invalidate(struct dentry *); |
252 | ||
253 | /* only used at mount-time */ | |
adc0e91a | 254 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
255 | |
256 | /* <clickety>-<click> the ramfs-type tree */ | |
257 | extern void d_genocide(struct dentry *); | |
258 | ||
60545d0d AV |
259 | extern void d_tmpfile(struct dentry *, struct inode *); |
260 | ||
1da177e4 LT |
261 | extern struct dentry *d_find_alias(struct inode *); |
262 | extern void d_prune_aliases(struct inode *); | |
263 | ||
264 | /* test whether we have any submounts in a subdir tree */ | |
265 | extern int have_submounts(struct dentry *); | |
848ac114 | 266 | extern int check_submounts_and_drop(struct dentry *); |
1da177e4 LT |
267 | |
268 | /* | |
269 | * This adds the entry to the hash queues. | |
270 | */ | |
271 | extern void d_rehash(struct dentry *); | |
272 | ||
273 | /** | |
274 | * d_add - add dentry to hash queues | |
275 | * @entry: dentry to add | |
276 | * @inode: The inode to attach to this dentry | |
277 | * | |
278 | * This adds the entry to the hash queues and initializes @inode. | |
279 | * The entry was actually filled in earlier during d_alloc(). | |
280 | */ | |
281 | ||
282 | static inline void d_add(struct dentry *entry, struct inode *inode) | |
283 | { | |
284 | d_instantiate(entry, inode); | |
285 | d_rehash(entry); | |
286 | } | |
287 | ||
288 | /** | |
289 | * d_add_unique - add dentry to hash queues without aliasing | |
290 | * @entry: dentry to add | |
291 | * @inode: The inode to attach to this dentry | |
292 | * | |
293 | * This adds the entry to the hash queues and initializes @inode. | |
294 | * The entry was actually filled in earlier during d_alloc(). | |
295 | */ | |
296 | static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode) | |
297 | { | |
298 | struct dentry *res; | |
299 | ||
300 | res = d_instantiate_unique(entry, inode); | |
301 | d_rehash(res != NULL ? res : entry); | |
302 | return res; | |
303 | } | |
304 | ||
fb2d5b86 NP |
305 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
306 | ||
1da177e4 LT |
307 | /* used for rename() and baskets */ |
308 | extern void d_move(struct dentry *, struct dentry *); | |
e2761a11 | 309 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
310 | |
311 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 312 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 313 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 314 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 315 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 316 | const struct qstr *name, unsigned *seq); |
31e6b01f | 317 | |
24924a20 | 318 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 319 | { |
98474236 | 320 | return dentry->d_lockref.count; |
84d08fa8 AV |
321 | } |
322 | ||
1da177e4 LT |
323 | /* validate "insecure" dentry pointer */ |
324 | extern int d_validate(struct dentry *, struct dentry *); | |
325 | ||
c23fbb6b ED |
326 | /* |
327 | * helper function for dentry_operations.d_dname() members | |
328 | */ | |
329 | extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 330 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 331 | |
02125a82 AV |
332 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
333 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 334 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 335 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 336 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 337 | |
1da177e4 LT |
338 | /* Allocation counts.. */ |
339 | ||
340 | /** | |
dc0474be | 341 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
342 | * @dentry: dentry to get a reference to |
343 | * | |
344 | * Given a dentry or %NULL pointer increment the reference count | |
345 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 346 | * destroyed when it has references. |
1da177e4 | 347 | */ |
b7ab39f6 NP |
348 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
349 | { | |
dc0474be | 350 | if (dentry) |
98474236 | 351 | dentry->d_lockref.count++; |
b7ab39f6 NP |
352 | return dentry; |
353 | } | |
2fd6b7f5 | 354 | |
1da177e4 LT |
355 | static inline struct dentry *dget(struct dentry *dentry) |
356 | { | |
98474236 WL |
357 | if (dentry) |
358 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
359 | return dentry; |
360 | } | |
361 | ||
b7ab39f6 | 362 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
363 | |
364 | /** | |
365 | * d_unhashed - is dentry hashed | |
366 | * @dentry: entry to check | |
367 | * | |
368 | * Returns true if the dentry passed is not currently hashed. | |
369 | */ | |
370 | ||
f0d3b3de | 371 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 372 | { |
dea3667b | 373 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
374 | } |
375 | ||
f0d3b3de | 376 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
377 | { |
378 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
379 | } | |
380 | ||
f0d3b3de | 381 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
382 | { |
383 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
384 | } | |
385 | ||
386 | static inline void dont_mount(struct dentry *dentry) | |
387 | { | |
388 | spin_lock(&dentry->d_lock); | |
389 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
390 | spin_unlock(&dentry->d_lock); | |
391 | } | |
392 | ||
1da177e4 LT |
393 | extern void dput(struct dentry *); |
394 | ||
f0d3b3de | 395 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
396 | { |
397 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
398 | } | |
399 | ||
f0d3b3de | 400 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 401 | { |
5f57cbcc | 402 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
403 | } |
404 | ||
b18825a7 DH |
405 | /* |
406 | * Directory cache entry type accessor functions. | |
407 | */ | |
408 | static inline void __d_set_type(struct dentry *dentry, unsigned type) | |
409 | { | |
410 | dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type; | |
411 | } | |
412 | ||
413 | static inline void __d_clear_type(struct dentry *dentry) | |
414 | { | |
415 | __d_set_type(dentry, DCACHE_MISS_TYPE); | |
416 | } | |
417 | ||
418 | static inline void d_set_type(struct dentry *dentry, unsigned type) | |
419 | { | |
420 | spin_lock(&dentry->d_lock); | |
421 | __d_set_type(dentry, type); | |
422 | spin_unlock(&dentry->d_lock); | |
423 | } | |
424 | ||
425 | static inline unsigned __d_entry_type(const struct dentry *dentry) | |
426 | { | |
427 | return dentry->d_flags & DCACHE_ENTRY_TYPE; | |
428 | } | |
429 | ||
430 | static inline bool d_is_directory(const struct dentry *dentry) | |
431 | { | |
432 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
433 | } | |
434 | ||
435 | static inline bool d_is_autodir(const struct dentry *dentry) | |
436 | { | |
437 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
438 | } | |
439 | ||
440 | static inline bool d_is_symlink(const struct dentry *dentry) | |
441 | { | |
442 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
443 | } | |
444 | ||
445 | static inline bool d_is_file(const struct dentry *dentry) | |
446 | { | |
447 | return __d_entry_type(dentry) == DCACHE_FILE_TYPE; | |
448 | } | |
449 | ||
450 | static inline bool d_is_negative(const struct dentry *dentry) | |
451 | { | |
452 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
453 | } | |
454 | ||
455 | static inline bool d_is_positive(const struct dentry *dentry) | |
456 | { | |
457 | return !d_is_negative(dentry); | |
458 | } | |
459 | ||
1da177e4 LT |
460 | extern int sysctl_vfs_cache_pressure; |
461 | ||
55f841ce GC |
462 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
463 | { | |
464 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
465 | } | |
1da177e4 | 466 | #endif /* __LINUX_DCACHE_H */ |