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> |
f4bcbe79 | 13 | #include <linux/stringhash.h> |
1da177e4 | 14 | |
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 | |
2bd03e49 | 31 | #define HASH_LEN_DECLARE u32 hash; u32 len |
a5c21dce | 32 | #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) |
26fe5750 | 33 | #else |
2bd03e49 | 34 | #define HASH_LEN_DECLARE u32 len; u32 hash |
a5c21dce | 35 | #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) |
26fe5750 LT |
36 | #endif |
37 | ||
1da177e4 LT |
38 | /* |
39 | * "quick string" -- eases parameter passing, but more importantly | |
40 | * saves "metadata" about the string (ie length and the hash). | |
41 | * | |
42 | * hash comes first so it snuggles against d_parent in the | |
43 | * dentry. | |
44 | */ | |
45 | struct qstr { | |
26fe5750 LT |
46 | union { |
47 | struct { | |
48 | HASH_LEN_DECLARE; | |
49 | }; | |
50 | u64 hash_len; | |
51 | }; | |
1da177e4 LT |
52 | const unsigned char *name; |
53 | }; | |
54 | ||
26fe5750 | 55 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
26fe5750 | 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 | ||
c2452f32 NP |
66 | /* |
67 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
68 | * give reasonable cacheline footprint with larger lines without the | |
69 | * large memory footprint increase). | |
70 | */ | |
71 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 72 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 73 | #else |
44a7d7a8 NP |
74 | # ifdef CONFIG_SMP |
75 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
76 | # else | |
77 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
78 | # endif | |
c2452f32 | 79 | #endif |
1da177e4 | 80 | |
98474236 WL |
81 | #define d_lock d_lockref.lock |
82 | ||
1da177e4 | 83 | struct dentry { |
44a7d7a8 | 84 | /* RCU lookup touched fields */ |
1da177e4 | 85 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 86 | seqcount_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 87 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
88 | struct dentry *d_parent; /* parent directory */ |
89 | struct qstr d_name; | |
44a7d7a8 NP |
90 | struct inode *d_inode; /* Where the name belongs to - NULL is |
91 | * negative */ | |
92 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
93 | ||
94 | /* Ref lookup also touches following */ | |
98474236 | 95 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
96 | const struct dentry_operations *d_op; |
97 | struct super_block *d_sb; /* The root of the dentry tree */ | |
98 | unsigned long d_time; /* used by d_revalidate */ | |
99 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 LT |
100 | |
101 | struct list_head d_lru; /* LRU list */ | |
946e51f2 AV |
102 | struct list_head d_child; /* child of parent list */ |
103 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 104 | /* |
946e51f2 | 105 | * d_alias and d_rcu can share memory |
5160ee6f ED |
106 | */ |
107 | union { | |
946e51f2 | 108 | struct hlist_node d_alias; /* inode alias list */ |
5160ee6f ED |
109 | struct rcu_head d_rcu; |
110 | } d_u; | |
1da177e4 LT |
111 | }; |
112 | ||
a90b9c05 IM |
113 | /* |
114 | * dentry->d_lock spinlock nesting subclasses: | |
115 | * | |
116 | * 0: normal | |
117 | * 1: nested | |
118 | */ | |
119 | enum dentry_d_lock_class | |
120 | { | |
121 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
122 | DENTRY_D_LOCK_NESTED | |
123 | }; | |
124 | ||
1da177e4 | 125 | struct dentry_operations { |
0b728e19 | 126 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 127 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 LT |
128 | int (*d_hash)(const struct dentry *, struct qstr *); |
129 | int (*d_compare)(const struct dentry *, const struct dentry *, | |
621e155a | 130 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 131 | int (*d_delete)(const struct dentry *); |
1da177e4 | 132 | void (*d_release)(struct dentry *); |
f0023bc6 | 133 | void (*d_prune)(struct dentry *); |
1da177e4 | 134 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 135 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 136 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 137 | int (*d_manage)(struct dentry *, bool); |
4bacc9c9 | 138 | struct inode *(*d_select_inode)(struct dentry *, unsigned); |
d101a125 | 139 | struct dentry *(*d_real)(struct dentry *, struct inode *); |
44a7d7a8 | 140 | } ____cacheline_aligned; |
1da177e4 | 141 | |
5eef7fa9 NP |
142 | /* |
143 | * Locking rules for dentry_operations callbacks are to be found in | |
144 | * Documentation/filesystems/Locking. Keep it updated! | |
145 | * | |
621e155a NP |
146 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
147 | * Keep it updated too! | |
1da177e4 LT |
148 | */ |
149 | ||
150 | /* d_flags entries */ | |
b18825a7 DH |
151 | #define DCACHE_OP_HASH 0x00000001 |
152 | #define DCACHE_OP_COMPARE 0x00000002 | |
153 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
154 | #define DCACHE_OP_DELETE 0x00000008 | |
155 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 156 | |
b18825a7 | 157 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
158 | /* This dentry is possibly not currently connected to the dcache tree, in |
159 | * which case its parent will either be itself, or will have this flag as | |
160 | * well. nfsd will not use a dentry with this bit set, but will first | |
161 | * endeavour to clear the bit either by discovering that it is connected, | |
162 | * or by performing lookup operations. Any filesystem which supports | |
163 | * nfsd_operations MUST have a lookup function which, if it finds a | |
164 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
165 | * dentry into place and return that dentry rather than the passed one, | |
166 | * typically using d_splice_alias. */ | |
1da177e4 | 167 | |
b18825a7 DH |
168 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
169 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 170 | |
b18825a7 DH |
171 | #define DCACHE_CANT_MOUNT 0x00000100 |
172 | #define DCACHE_GENOCIDE 0x00000200 | |
173 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 174 | |
b18825a7 | 175 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 176 | |
b18825a7 | 177 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
178 | /* this dentry has been "silly renamed" and has to be deleted on the last |
179 | * dput() */ | |
b18825a7 DH |
180 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
181 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 182 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 183 | |
b18825a7 DH |
184 | #define DCACHE_DENTRY_KILLED 0x00008000 |
185 | ||
186 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
187 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
188 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 189 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 190 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 191 | |
b18825a7 DH |
192 | #define DCACHE_LRU_LIST 0x00080000 |
193 | ||
194 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
195 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
196 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
197 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
198 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
199 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
200 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
201 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 202 | |
41edf278 | 203 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 204 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
4bacc9c9 | 205 | #define DCACHE_OP_SELECT_INODE 0x02000000 /* Unioned entry: dcache op selects inode */ |
41edf278 | 206 | |
0b81d077 | 207 | #define DCACHE_ENCRYPTED_WITH_KEY 0x04000000 /* dir is encrypted with a valid key */ |
d101a125 | 208 | #define DCACHE_OP_REAL 0x08000000 |
0b81d077 | 209 | |
74c3cbe3 | 210 | extern seqlock_t rename_lock; |
1da177e4 | 211 | |
1da177e4 LT |
212 | /* |
213 | * These are the low-level FS interfaces to the dcache.. | |
214 | */ | |
215 | extern void d_instantiate(struct dentry *, struct inode *); | |
216 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
b70a80e7 | 217 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
218 | extern void __d_drop(struct dentry *dentry); |
219 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 220 | extern void d_delete(struct dentry *); |
fb045adb | 221 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
222 | |
223 | /* allocate/de-allocate */ | |
224 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 225 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
1da177e4 | 226 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 227 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 228 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 229 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 230 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 231 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
232 | extern void shrink_dcache_sb(struct super_block *); |
233 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 234 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 235 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
236 | |
237 | /* only used at mount-time */ | |
adc0e91a | 238 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
239 | |
240 | /* <clickety>-<click> the ramfs-type tree */ | |
241 | extern void d_genocide(struct dentry *); | |
242 | ||
60545d0d AV |
243 | extern void d_tmpfile(struct dentry *, struct inode *); |
244 | ||
1da177e4 LT |
245 | extern struct dentry *d_find_alias(struct inode *); |
246 | extern void d_prune_aliases(struct inode *); | |
247 | ||
248 | /* test whether we have any submounts in a subdir tree */ | |
249 | extern int have_submounts(struct dentry *); | |
250 | ||
251 | /* | |
252 | * This adds the entry to the hash queues. | |
253 | */ | |
254 | extern void d_rehash(struct dentry *); | |
1da177e4 | 255 | |
34d0d19d | 256 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 257 | |
fb2d5b86 NP |
258 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
259 | ||
1da177e4 LT |
260 | /* used for rename() and baskets */ |
261 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 262 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 263 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
264 | |
265 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 266 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 267 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 268 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 269 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 270 | const struct qstr *name, unsigned *seq); |
31e6b01f | 271 | |
24924a20 | 272 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 273 | { |
98474236 | 274 | return dentry->d_lockref.count; |
84d08fa8 AV |
275 | } |
276 | ||
c23fbb6b ED |
277 | /* |
278 | * helper function for dentry_operations.d_dname() members | |
279 | */ | |
8db14860 NI |
280 | extern __printf(4, 5) |
281 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 282 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 283 | |
02125a82 AV |
284 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
285 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 286 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 287 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 288 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 289 | |
1da177e4 LT |
290 | /* Allocation counts.. */ |
291 | ||
292 | /** | |
dc0474be | 293 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
294 | * @dentry: dentry to get a reference to |
295 | * | |
296 | * Given a dentry or %NULL pointer increment the reference count | |
297 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 298 | * destroyed when it has references. |
1da177e4 | 299 | */ |
b7ab39f6 NP |
300 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
301 | { | |
dc0474be | 302 | if (dentry) |
98474236 | 303 | dentry->d_lockref.count++; |
b7ab39f6 NP |
304 | return dentry; |
305 | } | |
2fd6b7f5 | 306 | |
1da177e4 LT |
307 | static inline struct dentry *dget(struct dentry *dentry) |
308 | { | |
98474236 WL |
309 | if (dentry) |
310 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
311 | return dentry; |
312 | } | |
313 | ||
b7ab39f6 | 314 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
315 | |
316 | /** | |
317 | * d_unhashed - is dentry hashed | |
318 | * @dentry: entry to check | |
319 | * | |
320 | * Returns true if the dentry passed is not currently hashed. | |
321 | */ | |
322 | ||
f0d3b3de | 323 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 324 | { |
dea3667b | 325 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
326 | } |
327 | ||
f0d3b3de | 328 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
329 | { |
330 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
331 | } | |
332 | ||
f0d3b3de | 333 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
334 | { |
335 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
336 | } | |
337 | ||
338 | static inline void dont_mount(struct dentry *dentry) | |
339 | { | |
340 | spin_lock(&dentry->d_lock); | |
341 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
342 | spin_unlock(&dentry->d_lock); | |
343 | } | |
344 | ||
1da177e4 LT |
345 | extern void dput(struct dentry *); |
346 | ||
f0d3b3de | 347 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
348 | { |
349 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
350 | } | |
351 | ||
f0d3b3de | 352 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 353 | { |
5f57cbcc | 354 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
355 | } |
356 | ||
b18825a7 DH |
357 | /* |
358 | * Directory cache entry type accessor functions. | |
359 | */ | |
b18825a7 DH |
360 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
361 | { | |
a528aca7 | 362 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
363 | } |
364 | ||
e7f7d225 DH |
365 | static inline bool d_is_miss(const struct dentry *dentry) |
366 | { | |
367 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
368 | } | |
369 | ||
370 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
371 | { | |
372 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
373 | } | |
374 | ||
44b1d530 | 375 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
376 | { |
377 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
378 | } | |
379 | ||
380 | static inline bool d_is_autodir(const struct dentry *dentry) | |
381 | { | |
382 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
383 | } | |
384 | ||
44b1d530 MS |
385 | static inline bool d_is_dir(const struct dentry *dentry) |
386 | { | |
387 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
388 | } | |
389 | ||
b18825a7 DH |
390 | static inline bool d_is_symlink(const struct dentry *dentry) |
391 | { | |
392 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
393 | } | |
394 | ||
44bdb5e5 DH |
395 | static inline bool d_is_reg(const struct dentry *dentry) |
396 | { | |
397 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
398 | } | |
399 | ||
400 | static inline bool d_is_special(const struct dentry *dentry) | |
401 | { | |
402 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
403 | } | |
404 | ||
b18825a7 DH |
405 | static inline bool d_is_file(const struct dentry *dentry) |
406 | { | |
44bdb5e5 | 407 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
408 | } |
409 | ||
410 | static inline bool d_is_negative(const struct dentry *dentry) | |
411 | { | |
e7f7d225 DH |
412 | // TODO: check d_is_whiteout(dentry) also. |
413 | return d_is_miss(dentry); | |
b18825a7 DH |
414 | } |
415 | ||
416 | static inline bool d_is_positive(const struct dentry *dentry) | |
417 | { | |
418 | return !d_is_negative(dentry); | |
419 | } | |
420 | ||
525d27b2 DH |
421 | /** |
422 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
423 | * @dentry: The dentry in question | |
424 | * | |
425 | * Returns true if the dentry represents either an absent name or a name that | |
426 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
427 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
428 | * fallthrough marker in an opaque directory. | |
429 | * | |
430 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
431 | * dentries. It should not be used to look at some other filesystem's | |
432 | * dentries. (2) It should also be used in combination with d_inode() to get | |
433 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
434 | * type field of the flags may be set to something other than miss or whiteout. | |
435 | */ | |
436 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
437 | { | |
438 | return dentry->d_inode == NULL; | |
439 | } | |
440 | ||
441 | /** | |
442 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
443 | * @dentry: The dentry in question | |
444 | * | |
445 | * Returns true if the dentry represents a name that maps to an inode | |
446 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
447 | * that is represented on medium as a 0,0 chardev. | |
448 | * | |
449 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
450 | * dentries. It should not be used to look at some other filesystem's | |
451 | * dentries. (2) It should also be used in combination with d_inode() to get | |
452 | * the inode. | |
453 | */ | |
454 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
455 | { | |
456 | return dentry->d_inode != NULL; | |
457 | } | |
458 | ||
dc3f4198 AV |
459 | static inline int simple_positive(struct dentry *dentry) |
460 | { | |
461 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
462 | } | |
463 | ||
df1a085a DH |
464 | extern void d_set_fallthru(struct dentry *dentry); |
465 | ||
466 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
467 | { | |
468 | return dentry->d_flags & DCACHE_FALLTHRU; | |
469 | } | |
470 | ||
471 | ||
1da177e4 LT |
472 | extern int sysctl_vfs_cache_pressure; |
473 | ||
55f841ce GC |
474 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
475 | { | |
476 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
477 | } | |
155e35d4 DH |
478 | |
479 | /** | |
480 | * d_inode - Get the actual inode of this dentry | |
481 | * @dentry: The dentry to query | |
482 | * | |
483 | * This is the helper normal filesystems should use to get at their own inodes | |
484 | * in their own dentries and ignore the layering superimposed upon them. | |
485 | */ | |
486 | static inline struct inode *d_inode(const struct dentry *dentry) | |
487 | { | |
488 | return dentry->d_inode; | |
489 | } | |
490 | ||
491 | /** | |
492 | * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE() | |
493 | * @dentry: The dentry to query | |
494 | * | |
495 | * This is the helper normal filesystems should use to get at their own inodes | |
496 | * in their own dentries and ignore the layering superimposed upon them. | |
497 | */ | |
498 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
499 | { | |
500 | return ACCESS_ONCE(dentry->d_inode); | |
501 | } | |
502 | ||
503 | /** | |
504 | * d_backing_inode - Get upper or lower inode we should be using | |
505 | * @upper: The upper layer | |
506 | * | |
507 | * This is the helper that should be used to get at the inode that will be used | |
508 | * if this dentry were to be opened as a file. The inode may be on the upper | |
509 | * dentry or it may be on a lower dentry pinned by the upper. | |
510 | * | |
511 | * Normal filesystems should not use this to access their own inodes. | |
512 | */ | |
513 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
514 | { | |
515 | struct inode *inode = upper->d_inode; | |
516 | ||
517 | return inode; | |
518 | } | |
519 | ||
520 | /** | |
521 | * d_backing_dentry - Get upper or lower dentry we should be using | |
522 | * @upper: The upper layer | |
523 | * | |
524 | * This is the helper that should be used to get the dentry of the inode that | |
525 | * will be used if this dentry were opened as a file. It may be the upper | |
526 | * dentry or it may be a lower dentry pinned by the upper. | |
527 | * | |
528 | * Normal filesystems should not use this to access their own dentries. | |
529 | */ | |
530 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
531 | { | |
532 | return upper; | |
533 | } | |
534 | ||
d101a125 MS |
535 | static inline struct dentry *d_real(struct dentry *dentry) |
536 | { | |
537 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
538 | return dentry->d_op->d_real(dentry, NULL); | |
539 | else | |
540 | return dentry; | |
541 | } | |
542 | ||
54d5ca87 MS |
543 | static inline struct inode *vfs_select_inode(struct dentry *dentry, |
544 | unsigned open_flags) | |
545 | { | |
546 | struct inode *inode = d_inode(dentry); | |
547 | ||
548 | if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE)) | |
549 | inode = dentry->d_op->d_select_inode(dentry, open_flags); | |
550 | ||
551 | return inode; | |
552 | } | |
553 | ||
554 | ||
1da177e4 | 555 | #endif /* __LINUX_DCACHE_H */ |