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 | 13 | |
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 | |
2bd03e49 | 30 | #define HASH_LEN_DECLARE u32 hash; u32 len |
a5c21dce | 31 | #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) |
26fe5750 | 32 | #else |
2bd03e49 | 33 | #define HASH_LEN_DECLARE u32 len; u32 hash |
a5c21dce | 34 | #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) |
26fe5750 LT |
35 | #endif |
36 | ||
1da177e4 LT |
37 | /* |
38 | * "quick string" -- eases parameter passing, but more importantly | |
39 | * saves "metadata" about the string (ie length and the hash). | |
40 | * | |
41 | * hash comes first so it snuggles against d_parent in the | |
42 | * dentry. | |
43 | */ | |
44 | struct qstr { | |
26fe5750 LT |
45 | union { |
46 | struct { | |
47 | HASH_LEN_DECLARE; | |
48 | }; | |
49 | u64 hash_len; | |
50 | }; | |
1da177e4 LT |
51 | const unsigned char *name; |
52 | }; | |
53 | ||
26fe5750 LT |
54 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
55 | #define hashlen_hash(hashlen) ((u32) (hashlen)) | |
56 | #define hashlen_len(hashlen) ((u32)((hashlen) >> 32)) | |
9226b5b4 | 57 | #define hashlen_create(hash,len) (((u64)(len)<<32)|(u32)(hash)) |
26fe5750 | 58 | |
1da177e4 | 59 | struct dentry_stat_t { |
3942c07c GC |
60 | long nr_dentry; |
61 | long nr_unused; | |
62 | long age_limit; /* age in seconds */ | |
63 | long want_pages; /* pages requested by system */ | |
64 | long dummy[2]; | |
1da177e4 LT |
65 | }; |
66 | extern struct dentry_stat_t dentry_stat; | |
67 | ||
68 | /* Name hashing routines. Initial hash value */ | |
69 | /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ | |
70 | #define init_name_hash() 0 | |
71 | ||
72 | /* partial hash update function. Assume roughly 4 bits per character */ | |
73 | static inline unsigned long | |
74 | partial_name_hash(unsigned long c, unsigned long prevhash) | |
75 | { | |
76 | return (prevhash + (c << 4) + (c >> 4)) * 11; | |
77 | } | |
78 | ||
79 | /* | |
80 | * Finally: cut down the number of bits to a int value (and try to avoid | |
81 | * losing bits) | |
82 | */ | |
83 | static inline unsigned long end_name_hash(unsigned long hash) | |
84 | { | |
85 | return (unsigned int) hash; | |
86 | } | |
87 | ||
88 | /* Compute the hash for a name string. */ | |
0145acc2 | 89 | extern unsigned int full_name_hash(const unsigned char *, unsigned int); |
1da177e4 | 90 | |
c2452f32 NP |
91 | /* |
92 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
93 | * give reasonable cacheline footprint with larger lines without the | |
94 | * large memory footprint increase). | |
95 | */ | |
96 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 97 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 98 | #else |
44a7d7a8 NP |
99 | # ifdef CONFIG_SMP |
100 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
101 | # else | |
102 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
103 | # endif | |
c2452f32 | 104 | #endif |
1da177e4 | 105 | |
98474236 WL |
106 | #define d_lock d_lockref.lock |
107 | ||
1da177e4 | 108 | struct dentry { |
44a7d7a8 | 109 | /* RCU lookup touched fields */ |
1da177e4 | 110 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 111 | seqcount_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 112 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
113 | struct dentry *d_parent; /* parent directory */ |
114 | struct qstr d_name; | |
44a7d7a8 NP |
115 | struct inode *d_inode; /* Where the name belongs to - NULL is |
116 | * negative */ | |
117 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
118 | ||
119 | /* Ref lookup also touches following */ | |
98474236 | 120 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
121 | const struct dentry_operations *d_op; |
122 | struct super_block *d_sb; /* The root of the dentry tree */ | |
123 | unsigned long d_time; /* used by d_revalidate */ | |
124 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 LT |
125 | |
126 | struct list_head d_lru; /* LRU list */ | |
946e51f2 AV |
127 | struct list_head d_child; /* child of parent list */ |
128 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 129 | /* |
946e51f2 | 130 | * d_alias and d_rcu can share memory |
5160ee6f ED |
131 | */ |
132 | union { | |
946e51f2 | 133 | struct hlist_node d_alias; /* inode alias list */ |
5160ee6f ED |
134 | struct rcu_head d_rcu; |
135 | } d_u; | |
1da177e4 LT |
136 | }; |
137 | ||
a90b9c05 IM |
138 | /* |
139 | * dentry->d_lock spinlock nesting subclasses: | |
140 | * | |
141 | * 0: normal | |
142 | * 1: nested | |
143 | */ | |
144 | enum dentry_d_lock_class | |
145 | { | |
146 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
147 | DENTRY_D_LOCK_NESTED | |
148 | }; | |
149 | ||
1da177e4 | 150 | struct dentry_operations { |
0b728e19 | 151 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 152 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 LT |
153 | int (*d_hash)(const struct dentry *, struct qstr *); |
154 | int (*d_compare)(const struct dentry *, const struct dentry *, | |
621e155a | 155 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 156 | int (*d_delete)(const struct dentry *); |
1da177e4 | 157 | void (*d_release)(struct dentry *); |
f0023bc6 | 158 | void (*d_prune)(struct dentry *); |
1da177e4 | 159 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 160 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 161 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 162 | int (*d_manage)(struct dentry *, bool); |
4bacc9c9 | 163 | struct inode *(*d_select_inode)(struct dentry *, unsigned); |
44a7d7a8 | 164 | } ____cacheline_aligned; |
1da177e4 | 165 | |
5eef7fa9 NP |
166 | /* |
167 | * Locking rules for dentry_operations callbacks are to be found in | |
168 | * Documentation/filesystems/Locking. Keep it updated! | |
169 | * | |
621e155a NP |
170 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
171 | * Keep it updated too! | |
1da177e4 LT |
172 | */ |
173 | ||
174 | /* d_flags entries */ | |
b18825a7 DH |
175 | #define DCACHE_OP_HASH 0x00000001 |
176 | #define DCACHE_OP_COMPARE 0x00000002 | |
177 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
178 | #define DCACHE_OP_DELETE 0x00000008 | |
179 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 180 | |
b18825a7 | 181 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
182 | /* This dentry is possibly not currently connected to the dcache tree, in |
183 | * which case its parent will either be itself, or will have this flag as | |
184 | * well. nfsd will not use a dentry with this bit set, but will first | |
185 | * endeavour to clear the bit either by discovering that it is connected, | |
186 | * or by performing lookup operations. Any filesystem which supports | |
187 | * nfsd_operations MUST have a lookup function which, if it finds a | |
188 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
189 | * dentry into place and return that dentry rather than the passed one, | |
190 | * typically using d_splice_alias. */ | |
1da177e4 | 191 | |
b18825a7 DH |
192 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
193 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 194 | |
b18825a7 DH |
195 | #define DCACHE_CANT_MOUNT 0x00000100 |
196 | #define DCACHE_GENOCIDE 0x00000200 | |
197 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 198 | |
b18825a7 | 199 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 200 | |
b18825a7 | 201 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
202 | /* this dentry has been "silly renamed" and has to be deleted on the last |
203 | * dput() */ | |
b18825a7 DH |
204 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
205 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 206 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 207 | |
b18825a7 DH |
208 | #define DCACHE_DENTRY_KILLED 0x00008000 |
209 | ||
210 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
211 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
212 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 213 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 214 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 215 | |
b18825a7 DH |
216 | #define DCACHE_LRU_LIST 0x00080000 |
217 | ||
218 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
219 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
220 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
221 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
222 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
223 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
224 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
225 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 226 | |
41edf278 | 227 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 228 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
4bacc9c9 | 229 | #define DCACHE_OP_SELECT_INODE 0x02000000 /* Unioned entry: dcache op selects inode */ |
41edf278 | 230 | |
0b81d077 JK |
231 | #define DCACHE_ENCRYPTED_WITH_KEY 0x04000000 /* dir is encrypted with a valid key */ |
232 | ||
74c3cbe3 | 233 | extern seqlock_t rename_lock; |
1da177e4 | 234 | |
1da177e4 LT |
235 | /* |
236 | * These are the low-level FS interfaces to the dcache.. | |
237 | */ | |
238 | extern void d_instantiate(struct dentry *, struct inode *); | |
239 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
b70a80e7 | 240 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
241 | extern void __d_drop(struct dentry *dentry); |
242 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 243 | extern void d_delete(struct dentry *); |
fb045adb | 244 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
245 | |
246 | /* allocate/de-allocate */ | |
247 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 248 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
1da177e4 | 249 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 250 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 251 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 252 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 253 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 254 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
255 | extern void shrink_dcache_sb(struct super_block *); |
256 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 257 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 258 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
259 | |
260 | /* only used at mount-time */ | |
adc0e91a | 261 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
262 | |
263 | /* <clickety>-<click> the ramfs-type tree */ | |
264 | extern void d_genocide(struct dentry *); | |
265 | ||
60545d0d AV |
266 | extern void d_tmpfile(struct dentry *, struct inode *); |
267 | ||
1da177e4 LT |
268 | extern struct dentry *d_find_alias(struct inode *); |
269 | extern void d_prune_aliases(struct inode *); | |
270 | ||
271 | /* test whether we have any submounts in a subdir tree */ | |
272 | extern int have_submounts(struct dentry *); | |
273 | ||
274 | /* | |
275 | * This adds the entry to the hash queues. | |
276 | */ | |
277 | extern void d_rehash(struct dentry *); | |
1da177e4 | 278 | |
34d0d19d | 279 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 280 | |
fb2d5b86 NP |
281 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
282 | ||
1da177e4 LT |
283 | /* used for rename() and baskets */ |
284 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 285 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 286 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
287 | |
288 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 289 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 290 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 291 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 292 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 293 | const struct qstr *name, unsigned *seq); |
31e6b01f | 294 | |
24924a20 | 295 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 296 | { |
98474236 | 297 | return dentry->d_lockref.count; |
84d08fa8 AV |
298 | } |
299 | ||
c23fbb6b ED |
300 | /* |
301 | * helper function for dentry_operations.d_dname() members | |
302 | */ | |
8db14860 NI |
303 | extern __printf(4, 5) |
304 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 305 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 306 | |
02125a82 AV |
307 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
308 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 309 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 310 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 311 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 312 | |
1da177e4 LT |
313 | /* Allocation counts.. */ |
314 | ||
315 | /** | |
dc0474be | 316 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
317 | * @dentry: dentry to get a reference to |
318 | * | |
319 | * Given a dentry or %NULL pointer increment the reference count | |
320 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 321 | * destroyed when it has references. |
1da177e4 | 322 | */ |
b7ab39f6 NP |
323 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
324 | { | |
dc0474be | 325 | if (dentry) |
98474236 | 326 | dentry->d_lockref.count++; |
b7ab39f6 NP |
327 | return dentry; |
328 | } | |
2fd6b7f5 | 329 | |
1da177e4 LT |
330 | static inline struct dentry *dget(struct dentry *dentry) |
331 | { | |
98474236 WL |
332 | if (dentry) |
333 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
334 | return dentry; |
335 | } | |
336 | ||
b7ab39f6 | 337 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
338 | |
339 | /** | |
340 | * d_unhashed - is dentry hashed | |
341 | * @dentry: entry to check | |
342 | * | |
343 | * Returns true if the dentry passed is not currently hashed. | |
344 | */ | |
345 | ||
f0d3b3de | 346 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 347 | { |
dea3667b | 348 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
349 | } |
350 | ||
f0d3b3de | 351 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
352 | { |
353 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
354 | } | |
355 | ||
f0d3b3de | 356 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
357 | { |
358 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
359 | } | |
360 | ||
361 | static inline void dont_mount(struct dentry *dentry) | |
362 | { | |
363 | spin_lock(&dentry->d_lock); | |
364 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
365 | spin_unlock(&dentry->d_lock); | |
366 | } | |
367 | ||
1da177e4 LT |
368 | extern void dput(struct dentry *); |
369 | ||
f0d3b3de | 370 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
371 | { |
372 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
373 | } | |
374 | ||
f0d3b3de | 375 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 376 | { |
5f57cbcc | 377 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
378 | } |
379 | ||
b18825a7 DH |
380 | /* |
381 | * Directory cache entry type accessor functions. | |
382 | */ | |
b18825a7 DH |
383 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
384 | { | |
a528aca7 | 385 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
386 | } |
387 | ||
e7f7d225 DH |
388 | static inline bool d_is_miss(const struct dentry *dentry) |
389 | { | |
390 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
391 | } | |
392 | ||
393 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
394 | { | |
395 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
396 | } | |
397 | ||
44b1d530 | 398 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
399 | { |
400 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
401 | } | |
402 | ||
403 | static inline bool d_is_autodir(const struct dentry *dentry) | |
404 | { | |
405 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
406 | } | |
407 | ||
44b1d530 MS |
408 | static inline bool d_is_dir(const struct dentry *dentry) |
409 | { | |
410 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
411 | } | |
412 | ||
b18825a7 DH |
413 | static inline bool d_is_symlink(const struct dentry *dentry) |
414 | { | |
415 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
416 | } | |
417 | ||
44bdb5e5 DH |
418 | static inline bool d_is_reg(const struct dentry *dentry) |
419 | { | |
420 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
421 | } | |
422 | ||
423 | static inline bool d_is_special(const struct dentry *dentry) | |
424 | { | |
425 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
426 | } | |
427 | ||
b18825a7 DH |
428 | static inline bool d_is_file(const struct dentry *dentry) |
429 | { | |
44bdb5e5 | 430 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
431 | } |
432 | ||
433 | static inline bool d_is_negative(const struct dentry *dentry) | |
434 | { | |
e7f7d225 DH |
435 | // TODO: check d_is_whiteout(dentry) also. |
436 | return d_is_miss(dentry); | |
b18825a7 DH |
437 | } |
438 | ||
439 | static inline bool d_is_positive(const struct dentry *dentry) | |
440 | { | |
441 | return !d_is_negative(dentry); | |
442 | } | |
443 | ||
525d27b2 DH |
444 | /** |
445 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
446 | * @dentry: The dentry in question | |
447 | * | |
448 | * Returns true if the dentry represents either an absent name or a name that | |
449 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
450 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
451 | * fallthrough marker in an opaque directory. | |
452 | * | |
453 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
454 | * dentries. It should not be used to look at some other filesystem's | |
455 | * dentries. (2) It should also be used in combination with d_inode() to get | |
456 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
457 | * type field of the flags may be set to something other than miss or whiteout. | |
458 | */ | |
459 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
460 | { | |
461 | return dentry->d_inode == NULL; | |
462 | } | |
463 | ||
464 | /** | |
465 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
466 | * @dentry: The dentry in question | |
467 | * | |
468 | * Returns true if the dentry represents a name that maps to an inode | |
469 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
470 | * that is represented on medium as a 0,0 chardev. | |
471 | * | |
472 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
473 | * dentries. It should not be used to look at some other filesystem's | |
474 | * dentries. (2) It should also be used in combination with d_inode() to get | |
475 | * the inode. | |
476 | */ | |
477 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
478 | { | |
479 | return dentry->d_inode != NULL; | |
480 | } | |
481 | ||
dc3f4198 AV |
482 | static inline int simple_positive(struct dentry *dentry) |
483 | { | |
484 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
485 | } | |
486 | ||
df1a085a DH |
487 | extern void d_set_fallthru(struct dentry *dentry); |
488 | ||
489 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
490 | { | |
491 | return dentry->d_flags & DCACHE_FALLTHRU; | |
492 | } | |
493 | ||
494 | ||
1da177e4 LT |
495 | extern int sysctl_vfs_cache_pressure; |
496 | ||
55f841ce GC |
497 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
498 | { | |
499 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
500 | } | |
155e35d4 DH |
501 | |
502 | /** | |
503 | * d_inode - Get the actual inode of this dentry | |
504 | * @dentry: The dentry to query | |
505 | * | |
506 | * This is the helper normal filesystems should use to get at their own inodes | |
507 | * in their own dentries and ignore the layering superimposed upon them. | |
508 | */ | |
509 | static inline struct inode *d_inode(const struct dentry *dentry) | |
510 | { | |
511 | return dentry->d_inode; | |
512 | } | |
513 | ||
514 | /** | |
515 | * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE() | |
516 | * @dentry: The dentry to query | |
517 | * | |
518 | * This is the helper normal filesystems should use to get at their own inodes | |
519 | * in their own dentries and ignore the layering superimposed upon them. | |
520 | */ | |
521 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
522 | { | |
523 | return ACCESS_ONCE(dentry->d_inode); | |
524 | } | |
525 | ||
526 | /** | |
527 | * d_backing_inode - Get upper or lower inode we should be using | |
528 | * @upper: The upper layer | |
529 | * | |
530 | * This is the helper that should be used to get at the inode that will be used | |
531 | * if this dentry were to be opened as a file. The inode may be on the upper | |
532 | * dentry or it may be on a lower dentry pinned by the upper. | |
533 | * | |
534 | * Normal filesystems should not use this to access their own inodes. | |
535 | */ | |
536 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
537 | { | |
538 | struct inode *inode = upper->d_inode; | |
539 | ||
540 | return inode; | |
541 | } | |
542 | ||
543 | /** | |
544 | * d_backing_dentry - Get upper or lower dentry we should be using | |
545 | * @upper: The upper layer | |
546 | * | |
547 | * This is the helper that should be used to get the dentry of the inode that | |
548 | * will be used if this dentry were opened as a file. It may be the upper | |
549 | * dentry or it may be a lower dentry pinned by the upper. | |
550 | * | |
551 | * Normal filesystems should not use this to access their own dentries. | |
552 | */ | |
553 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
554 | { | |
555 | return upper; | |
556 | } | |
557 | ||
1da177e4 | 558 | #endif /* __LINUX_DCACHE_H */ |