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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> | |
1da177e4 LT |
12 | |
13 | struct nameidata; | |
cf28b486 | 14 | struct path; |
1da177e4 LT |
15 | struct vfsmount; |
16 | ||
17 | /* | |
18 | * linux/include/linux/dcache.h | |
19 | * | |
20 | * Dirent cache data structures | |
21 | * | |
22 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
23 | * with heavy changes by Linus Torvalds | |
24 | */ | |
25 | ||
26 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
27 | ||
26fe5750 LT |
28 | /* The hash is always the low bits of hash_len */ |
29 | #ifdef __LITTLE_ENDIAN | |
30 | #define HASH_LEN_DECLARE u32 hash; u32 len; | |
31 | #else | |
32 | #define HASH_LEN_DECLARE u32 len; u32 hash; | |
33 | #endif | |
34 | ||
1da177e4 LT |
35 | /* |
36 | * "quick string" -- eases parameter passing, but more importantly | |
37 | * saves "metadata" about the string (ie length and the hash). | |
38 | * | |
39 | * hash comes first so it snuggles against d_parent in the | |
40 | * dentry. | |
41 | */ | |
42 | struct qstr { | |
26fe5750 LT |
43 | union { |
44 | struct { | |
45 | HASH_LEN_DECLARE; | |
46 | }; | |
47 | u64 hash_len; | |
48 | }; | |
1da177e4 LT |
49 | const unsigned char *name; |
50 | }; | |
51 | ||
26fe5750 LT |
52 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
53 | #define hashlen_hash(hashlen) ((u32) (hashlen)) | |
54 | #define hashlen_len(hashlen) ((u32)((hashlen) >> 32)) | |
55 | ||
1da177e4 LT |
56 | struct dentry_stat_t { |
57 | int nr_dentry; | |
58 | int nr_unused; | |
59 | int age_limit; /* age in seconds */ | |
60 | int want_pages; /* pages requested by system */ | |
61 | int dummy[2]; | |
62 | }; | |
63 | extern struct dentry_stat_t dentry_stat; | |
64 | ||
65 | /* Name hashing routines. Initial hash value */ | |
66 | /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ | |
67 | #define init_name_hash() 0 | |
68 | ||
69 | /* partial hash update function. Assume roughly 4 bits per character */ | |
70 | static inline unsigned long | |
71 | partial_name_hash(unsigned long c, unsigned long prevhash) | |
72 | { | |
73 | return (prevhash + (c << 4) + (c >> 4)) * 11; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Finally: cut down the number of bits to a int value (and try to avoid | |
78 | * losing bits) | |
79 | */ | |
80 | static inline unsigned long end_name_hash(unsigned long hash) | |
81 | { | |
82 | return (unsigned int) hash; | |
83 | } | |
84 | ||
85 | /* Compute the hash for a name string. */ | |
0145acc2 | 86 | extern unsigned int full_name_hash(const unsigned char *, unsigned int); |
1da177e4 | 87 | |
c2452f32 NP |
88 | /* |
89 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
90 | * give reasonable cacheline footprint with larger lines without the | |
91 | * large memory footprint increase). | |
92 | */ | |
93 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 94 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 95 | #else |
44a7d7a8 NP |
96 | # ifdef CONFIG_SMP |
97 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
98 | # else | |
99 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
100 | # endif | |
c2452f32 | 101 | #endif |
1da177e4 LT |
102 | |
103 | struct dentry { | |
44a7d7a8 | 104 | /* RCU lookup touched fields */ |
1da177e4 | 105 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 106 | seqcount_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 107 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
108 | struct dentry *d_parent; /* parent directory */ |
109 | struct qstr d_name; | |
44a7d7a8 NP |
110 | struct inode *d_inode; /* Where the name belongs to - NULL is |
111 | * negative */ | |
112 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
113 | ||
114 | /* Ref lookup also touches following */ | |
115 | unsigned int d_count; /* protected by d_lock */ | |
116 | spinlock_t d_lock; /* per dentry lock */ | |
117 | const struct dentry_operations *d_op; | |
118 | struct super_block *d_sb; /* The root of the dentry tree */ | |
119 | unsigned long d_time; /* used by d_revalidate */ | |
120 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 LT |
121 | |
122 | struct list_head d_lru; /* LRU list */ | |
5160ee6f ED |
123 | /* |
124 | * d_child and d_rcu can share memory | |
125 | */ | |
126 | union { | |
127 | struct list_head d_child; /* child of parent list */ | |
128 | struct rcu_head d_rcu; | |
129 | } d_u; | |
1da177e4 | 130 | struct list_head d_subdirs; /* our children */ |
b3d9b7a3 | 131 | struct hlist_node d_alias; /* inode alias list */ |
1da177e4 LT |
132 | }; |
133 | ||
a90b9c05 IM |
134 | /* |
135 | * dentry->d_lock spinlock nesting subclasses: | |
136 | * | |
137 | * 0: normal | |
138 | * 1: nested | |
139 | */ | |
140 | enum dentry_d_lock_class | |
141 | { | |
142 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
143 | DENTRY_D_LOCK_NESTED | |
144 | }; | |
145 | ||
1da177e4 | 146 | struct dentry_operations { |
0b728e19 | 147 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 148 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 LT |
149 | int (*d_hash)(const struct dentry *, struct qstr *); |
150 | int (*d_compare)(const struct dentry *, const struct dentry *, | |
621e155a | 151 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 152 | int (*d_delete)(const struct dentry *); |
1da177e4 | 153 | void (*d_release)(struct dentry *); |
f0023bc6 | 154 | void (*d_prune)(struct dentry *); |
1da177e4 | 155 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 156 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 157 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 158 | int (*d_manage)(struct dentry *, bool); |
44a7d7a8 | 159 | } ____cacheline_aligned; |
1da177e4 | 160 | |
5eef7fa9 NP |
161 | /* |
162 | * Locking rules for dentry_operations callbacks are to be found in | |
163 | * Documentation/filesystems/Locking. Keep it updated! | |
164 | * | |
621e155a NP |
165 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
166 | * Keep it updated too! | |
1da177e4 LT |
167 | */ |
168 | ||
169 | /* d_flags entries */ | |
830c0f0e LT |
170 | #define DCACHE_OP_HASH 0x0001 |
171 | #define DCACHE_OP_COMPARE 0x0002 | |
172 | #define DCACHE_OP_REVALIDATE 0x0004 | |
173 | #define DCACHE_OP_DELETE 0x0008 | |
f0023bc6 | 174 | #define DCACHE_OP_PRUNE 0x0010 |
5f57cbcc | 175 | |
f0023bc6 | 176 | #define DCACHE_DISCONNECTED 0x0020 |
5f57cbcc NP |
177 | /* This dentry is possibly not currently connected to the dcache tree, in |
178 | * which case its parent will either be itself, or will have this flag as | |
179 | * well. nfsd will not use a dentry with this bit set, but will first | |
180 | * endeavour to clear the bit either by discovering that it is connected, | |
181 | * or by performing lookup operations. Any filesystem which supports | |
182 | * nfsd_operations MUST have a lookup function which, if it finds a | |
183 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
184 | * dentry into place and return that dentry rather than the passed one, | |
185 | * typically using d_splice_alias. */ | |
1da177e4 | 186 | |
f0023bc6 SW |
187 | #define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */ |
188 | #define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 189 | |
d83c49f3 | 190 | #define DCACHE_CANT_MOUNT 0x0100 |
949854d0 | 191 | #define DCACHE_GENOCIDE 0x0200 |
eaf5f907 | 192 | #define DCACHE_SHRINK_LIST 0x0400 |
5f57cbcc | 193 | |
ecf3d1f1 JL |
194 | #define DCACHE_OP_WEAK_REVALIDATE 0x0800 |
195 | ||
830c0f0e LT |
196 | #define DCACHE_NFSFS_RENAMED 0x1000 |
197 | /* this dentry has been "silly renamed" and has to be deleted on the last | |
198 | * dput() */ | |
199 | #define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */ | |
200 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000 | |
201 | /* Parent inode is watched by some fsnotify listener */ | |
fb045adb | 202 | |
9875cf80 DH |
203 | #define DCACHE_MOUNTED 0x10000 /* is a mountpoint */ |
204 | #define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */ | |
cc53ce53 | 205 | #define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */ |
9875cf80 | 206 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 207 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 208 | |
b161dfa6 MS |
209 | #define DCACHE_DENTRY_KILLED 0x100000 |
210 | ||
74c3cbe3 | 211 | extern seqlock_t rename_lock; |
1da177e4 | 212 | |
1da177e4 LT |
213 | static inline int dname_external(struct dentry *dentry) |
214 | { | |
215 | return dentry->d_name.name != dentry->d_iname; | |
216 | } | |
217 | ||
218 | /* | |
219 | * These are the low-level FS interfaces to the dcache.. | |
220 | */ | |
221 | extern void d_instantiate(struct dentry *, struct inode *); | |
222 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
770bfad8 | 223 | extern struct dentry * d_materialise_unique(struct dentry *, struct inode *); |
789680d1 NP |
224 | extern void __d_drop(struct dentry *dentry); |
225 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 226 | extern void d_delete(struct dentry *); |
fb045adb | 227 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
228 | |
229 | /* allocate/de-allocate */ | |
230 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 231 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
1da177e4 | 232 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 233 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
46f72b34 | 234 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 235 | extern struct dentry * d_obtain_alias(struct inode *); |
1da177e4 LT |
236 | extern void shrink_dcache_sb(struct super_block *); |
237 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 238 | extern void shrink_dcache_for_umount(struct super_block *); |
1da177e4 LT |
239 | extern int d_invalidate(struct dentry *); |
240 | ||
241 | /* only used at mount-time */ | |
adc0e91a | 242 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
243 | |
244 | /* <clickety>-<click> the ramfs-type tree */ | |
245 | extern void d_genocide(struct dentry *); | |
246 | ||
60545d0d AV |
247 | extern void d_tmpfile(struct dentry *, struct inode *); |
248 | ||
1da177e4 LT |
249 | extern struct dentry *d_find_alias(struct inode *); |
250 | extern void d_prune_aliases(struct inode *); | |
251 | ||
252 | /* test whether we have any submounts in a subdir tree */ | |
253 | extern int have_submounts(struct dentry *); | |
254 | ||
255 | /* | |
256 | * This adds the entry to the hash queues. | |
257 | */ | |
258 | extern void d_rehash(struct dentry *); | |
259 | ||
260 | /** | |
261 | * d_add - add dentry to hash queues | |
262 | * @entry: dentry to add | |
263 | * @inode: The inode to attach to this dentry | |
264 | * | |
265 | * This adds the entry to the hash queues and initializes @inode. | |
266 | * The entry was actually filled in earlier during d_alloc(). | |
267 | */ | |
268 | ||
269 | static inline void d_add(struct dentry *entry, struct inode *inode) | |
270 | { | |
271 | d_instantiate(entry, inode); | |
272 | d_rehash(entry); | |
273 | } | |
274 | ||
275 | /** | |
276 | * d_add_unique - add dentry to hash queues without aliasing | |
277 | * @entry: dentry to add | |
278 | * @inode: The inode to attach to this dentry | |
279 | * | |
280 | * This adds the entry to the hash queues and initializes @inode. | |
281 | * The entry was actually filled in earlier during d_alloc(). | |
282 | */ | |
283 | static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode) | |
284 | { | |
285 | struct dentry *res; | |
286 | ||
287 | res = d_instantiate_unique(entry, inode); | |
288 | d_rehash(res != NULL ? res : entry); | |
289 | return res; | |
290 | } | |
291 | ||
fb2d5b86 NP |
292 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
293 | ||
1da177e4 LT |
294 | /* used for rename() and baskets */ |
295 | extern void d_move(struct dentry *, struct dentry *); | |
e2761a11 | 296 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
297 | |
298 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 299 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 300 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 301 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 302 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 303 | const struct qstr *name, unsigned *seq); |
31e6b01f NP |
304 | |
305 | /** | |
306 | * __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok | |
307 | * @dentry: dentry to take a ref on | |
308 | * @seq: seqcount to verify against | |
2a8c0c68 | 309 | * Returns: 0 on failure, else 1. |
31e6b01f NP |
310 | * |
311 | * __d_rcu_to_refcount operates on a dentry,seq pair that was returned | |
312 | * by __d_lookup_rcu, to get a reference on an rcu-walk dentry. | |
313 | */ | |
314 | static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq) | |
315 | { | |
316 | int ret = 0; | |
317 | ||
318 | assert_spin_locked(&dentry->d_lock); | |
319 | if (!read_seqcount_retry(&dentry->d_seq, seq)) { | |
320 | ret = 1; | |
321 | dentry->d_count++; | |
322 | } | |
323 | ||
324 | return ret; | |
325 | } | |
1da177e4 LT |
326 | |
327 | /* validate "insecure" dentry pointer */ | |
328 | extern int d_validate(struct dentry *, struct dentry *); | |
329 | ||
c23fbb6b ED |
330 | /* |
331 | * helper function for dentry_operations.d_dname() members | |
332 | */ | |
333 | extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
334 | ||
02125a82 AV |
335 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
336 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 337 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 338 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 339 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 340 | |
1da177e4 LT |
341 | /* Allocation counts.. */ |
342 | ||
343 | /** | |
dc0474be | 344 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
345 | * @dentry: dentry to get a reference to |
346 | * | |
347 | * Given a dentry or %NULL pointer increment the reference count | |
348 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 349 | * destroyed when it has references. |
1da177e4 | 350 | */ |
b7ab39f6 NP |
351 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
352 | { | |
dc0474be | 353 | if (dentry) |
b7ab39f6 | 354 | dentry->d_count++; |
b7ab39f6 NP |
355 | return dentry; |
356 | } | |
2fd6b7f5 | 357 | |
1da177e4 LT |
358 | static inline struct dentry *dget(struct dentry *dentry) |
359 | { | |
360 | if (dentry) { | |
b7ab39f6 NP |
361 | spin_lock(&dentry->d_lock); |
362 | dget_dlock(dentry); | |
363 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
364 | } |
365 | return dentry; | |
366 | } | |
367 | ||
b7ab39f6 | 368 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
369 | |
370 | /** | |
371 | * d_unhashed - is dentry hashed | |
372 | * @dentry: entry to check | |
373 | * | |
374 | * Returns true if the dentry passed is not currently hashed. | |
375 | */ | |
376 | ||
377 | static inline int d_unhashed(struct dentry *dentry) | |
378 | { | |
dea3667b | 379 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
380 | } |
381 | ||
f3da392e AD |
382 | static inline int d_unlinked(struct dentry *dentry) |
383 | { | |
384 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
385 | } | |
386 | ||
d83c49f3 AV |
387 | static inline int cant_mount(struct dentry *dentry) |
388 | { | |
389 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
390 | } | |
391 | ||
392 | static inline void dont_mount(struct dentry *dentry) | |
393 | { | |
394 | spin_lock(&dentry->d_lock); | |
395 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
396 | spin_unlock(&dentry->d_lock); | |
397 | } | |
398 | ||
1da177e4 LT |
399 | extern void dput(struct dentry *); |
400 | ||
cc53ce53 DH |
401 | static inline bool d_managed(struct dentry *dentry) |
402 | { | |
403 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
404 | } | |
405 | ||
406 | static inline bool d_mountpoint(struct dentry *dentry) | |
1da177e4 | 407 | { |
5f57cbcc | 408 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
409 | } |
410 | ||
1da177e4 LT |
411 | extern int sysctl_vfs_cache_pressure; |
412 | ||
1da177e4 | 413 | #endif /* __LINUX_DCACHE_H */ |