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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 | 100 | |
d9171b93 AV |
101 | union { |
102 | struct list_head d_lru; /* LRU list */ | |
103 | wait_queue_head_t *d_wait; /* in-lookup ones only */ | |
104 | }; | |
946e51f2 AV |
105 | struct list_head d_child; /* child of parent list */ |
106 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 107 | /* |
946e51f2 | 108 | * d_alias and d_rcu can share memory |
5160ee6f ED |
109 | */ |
110 | union { | |
946e51f2 | 111 | struct hlist_node d_alias; /* inode alias list */ |
94bdd655 | 112 | struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ |
5160ee6f ED |
113 | struct rcu_head d_rcu; |
114 | } d_u; | |
1da177e4 LT |
115 | }; |
116 | ||
a90b9c05 IM |
117 | /* |
118 | * dentry->d_lock spinlock nesting subclasses: | |
119 | * | |
120 | * 0: normal | |
121 | * 1: nested | |
122 | */ | |
123 | enum dentry_d_lock_class | |
124 | { | |
125 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
126 | DENTRY_D_LOCK_NESTED | |
127 | }; | |
128 | ||
1da177e4 | 129 | struct dentry_operations { |
0b728e19 | 130 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 131 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 LT |
132 | int (*d_hash)(const struct dentry *, struct qstr *); |
133 | int (*d_compare)(const struct dentry *, const struct dentry *, | |
621e155a | 134 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 135 | int (*d_delete)(const struct dentry *); |
1da177e4 | 136 | void (*d_release)(struct dentry *); |
f0023bc6 | 137 | void (*d_prune)(struct dentry *); |
1da177e4 | 138 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 139 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 140 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 141 | int (*d_manage)(struct dentry *, bool); |
2d902671 | 142 | struct dentry *(*d_real)(struct dentry *, const struct inode *, unsigned int); |
44a7d7a8 | 143 | } ____cacheline_aligned; |
1da177e4 | 144 | |
5eef7fa9 NP |
145 | /* |
146 | * Locking rules for dentry_operations callbacks are to be found in | |
147 | * Documentation/filesystems/Locking. Keep it updated! | |
148 | * | |
621e155a NP |
149 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
150 | * Keep it updated too! | |
1da177e4 LT |
151 | */ |
152 | ||
153 | /* d_flags entries */ | |
b18825a7 DH |
154 | #define DCACHE_OP_HASH 0x00000001 |
155 | #define DCACHE_OP_COMPARE 0x00000002 | |
156 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
157 | #define DCACHE_OP_DELETE 0x00000008 | |
158 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 159 | |
b18825a7 | 160 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
161 | /* This dentry is possibly not currently connected to the dcache tree, in |
162 | * which case its parent will either be itself, or will have this flag as | |
163 | * well. nfsd will not use a dentry with this bit set, but will first | |
164 | * endeavour to clear the bit either by discovering that it is connected, | |
165 | * or by performing lookup operations. Any filesystem which supports | |
166 | * nfsd_operations MUST have a lookup function which, if it finds a | |
167 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
168 | * dentry into place and return that dentry rather than the passed one, | |
169 | * typically using d_splice_alias. */ | |
1da177e4 | 170 | |
b18825a7 DH |
171 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
172 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 173 | |
b18825a7 DH |
174 | #define DCACHE_CANT_MOUNT 0x00000100 |
175 | #define DCACHE_GENOCIDE 0x00000200 | |
176 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 177 | |
b18825a7 | 178 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 179 | |
b18825a7 | 180 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
181 | /* this dentry has been "silly renamed" and has to be deleted on the last |
182 | * dput() */ | |
b18825a7 DH |
183 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
184 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 185 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 186 | |
b18825a7 DH |
187 | #define DCACHE_DENTRY_KILLED 0x00008000 |
188 | ||
189 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
190 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
191 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 192 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 193 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 194 | |
b18825a7 DH |
195 | #define DCACHE_LRU_LIST 0x00080000 |
196 | ||
197 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
198 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
199 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
200 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
201 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
202 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
203 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
204 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 205 | |
41edf278 | 206 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 207 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
2d902671 MS |
208 | #define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */ |
209 | #define DCACHE_OP_REAL 0x04000000 | |
0b81d077 | 210 | |
85c7f810 | 211 | #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ |
ba65dc5e | 212 | #define DCACHE_DENTRY_CURSOR 0x20000000 |
85c7f810 | 213 | |
74c3cbe3 | 214 | extern seqlock_t rename_lock; |
1da177e4 | 215 | |
1da177e4 LT |
216 | /* |
217 | * These are the low-level FS interfaces to the dcache.. | |
218 | */ | |
219 | extern void d_instantiate(struct dentry *, struct inode *); | |
220 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
b70a80e7 | 221 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
222 | extern void __d_drop(struct dentry *dentry); |
223 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 224 | extern void d_delete(struct dentry *); |
fb045adb | 225 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
226 | |
227 | /* allocate/de-allocate */ | |
228 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 229 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
d9171b93 AV |
230 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
231 | wait_queue_head_t *); | |
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 *); |
668d0cd5 | 234 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 235 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 236 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 237 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
238 | extern void shrink_dcache_sb(struct super_block *); |
239 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 240 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 241 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
242 | |
243 | /* only used at mount-time */ | |
adc0e91a | 244 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
245 | |
246 | /* <clickety>-<click> the ramfs-type tree */ | |
247 | extern void d_genocide(struct dentry *); | |
248 | ||
60545d0d AV |
249 | extern void d_tmpfile(struct dentry *, struct inode *); |
250 | ||
1da177e4 LT |
251 | extern struct dentry *d_find_alias(struct inode *); |
252 | extern void d_prune_aliases(struct inode *); | |
253 | ||
254 | /* test whether we have any submounts in a subdir tree */ | |
255 | extern int have_submounts(struct dentry *); | |
256 | ||
257 | /* | |
258 | * This adds the entry to the hash queues. | |
259 | */ | |
260 | extern void d_rehash(struct dentry *); | |
1da177e4 | 261 | |
34d0d19d | 262 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 263 | |
fb2d5b86 NP |
264 | extern void dentry_update_name_case(struct dentry *, struct qstr *); |
265 | ||
1da177e4 LT |
266 | /* used for rename() and baskets */ |
267 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 268 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 269 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
270 | |
271 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 272 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 273 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 274 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 275 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 276 | const struct qstr *name, unsigned *seq); |
31e6b01f | 277 | |
24924a20 | 278 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 279 | { |
98474236 | 280 | return dentry->d_lockref.count; |
84d08fa8 AV |
281 | } |
282 | ||
c23fbb6b ED |
283 | /* |
284 | * helper function for dentry_operations.d_dname() members | |
285 | */ | |
8db14860 NI |
286 | extern __printf(4, 5) |
287 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 288 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 289 | |
02125a82 AV |
290 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
291 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 292 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 293 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 294 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 295 | |
1da177e4 LT |
296 | /* Allocation counts.. */ |
297 | ||
298 | /** | |
dc0474be | 299 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
300 | * @dentry: dentry to get a reference to |
301 | * | |
302 | * Given a dentry or %NULL pointer increment the reference count | |
303 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 304 | * destroyed when it has references. |
1da177e4 | 305 | */ |
b7ab39f6 NP |
306 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
307 | { | |
dc0474be | 308 | if (dentry) |
98474236 | 309 | dentry->d_lockref.count++; |
b7ab39f6 NP |
310 | return dentry; |
311 | } | |
2fd6b7f5 | 312 | |
1da177e4 LT |
313 | static inline struct dentry *dget(struct dentry *dentry) |
314 | { | |
98474236 WL |
315 | if (dentry) |
316 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
317 | return dentry; |
318 | } | |
319 | ||
b7ab39f6 | 320 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
321 | |
322 | /** | |
323 | * d_unhashed - is dentry hashed | |
324 | * @dentry: entry to check | |
325 | * | |
326 | * Returns true if the dentry passed is not currently hashed. | |
327 | */ | |
328 | ||
f0d3b3de | 329 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 330 | { |
dea3667b | 331 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
332 | } |
333 | ||
f0d3b3de | 334 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
335 | { |
336 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
337 | } | |
338 | ||
f0d3b3de | 339 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
340 | { |
341 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
342 | } | |
343 | ||
344 | static inline void dont_mount(struct dentry *dentry) | |
345 | { | |
346 | spin_lock(&dentry->d_lock); | |
347 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
348 | spin_unlock(&dentry->d_lock); | |
349 | } | |
350 | ||
85c7f810 AV |
351 | extern void __d_lookup_done(struct dentry *); |
352 | ||
353 | static inline int d_in_lookup(struct dentry *dentry) | |
354 | { | |
355 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
356 | } | |
357 | ||
358 | static inline void d_lookup_done(struct dentry *dentry) | |
359 | { | |
360 | if (unlikely(d_in_lookup(dentry))) { | |
361 | spin_lock(&dentry->d_lock); | |
362 | __d_lookup_done(dentry); | |
363 | spin_unlock(&dentry->d_lock); | |
364 | } | |
365 | } | |
366 | ||
1da177e4 LT |
367 | extern void dput(struct dentry *); |
368 | ||
f0d3b3de | 369 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
370 | { |
371 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
372 | } | |
373 | ||
f0d3b3de | 374 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 375 | { |
5f57cbcc | 376 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
377 | } |
378 | ||
b18825a7 DH |
379 | /* |
380 | * Directory cache entry type accessor functions. | |
381 | */ | |
b18825a7 DH |
382 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
383 | { | |
a528aca7 | 384 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
385 | } |
386 | ||
e7f7d225 DH |
387 | static inline bool d_is_miss(const struct dentry *dentry) |
388 | { | |
389 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
390 | } | |
391 | ||
392 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
393 | { | |
394 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
395 | } | |
396 | ||
44b1d530 | 397 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
398 | { |
399 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
400 | } | |
401 | ||
402 | static inline bool d_is_autodir(const struct dentry *dentry) | |
403 | { | |
404 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
405 | } | |
406 | ||
44b1d530 MS |
407 | static inline bool d_is_dir(const struct dentry *dentry) |
408 | { | |
409 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
410 | } | |
411 | ||
b18825a7 DH |
412 | static inline bool d_is_symlink(const struct dentry *dentry) |
413 | { | |
414 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
415 | } | |
416 | ||
44bdb5e5 DH |
417 | static inline bool d_is_reg(const struct dentry *dentry) |
418 | { | |
419 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
420 | } | |
421 | ||
422 | static inline bool d_is_special(const struct dentry *dentry) | |
423 | { | |
424 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
425 | } | |
426 | ||
b18825a7 DH |
427 | static inline bool d_is_file(const struct dentry *dentry) |
428 | { | |
44bdb5e5 | 429 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
430 | } |
431 | ||
432 | static inline bool d_is_negative(const struct dentry *dentry) | |
433 | { | |
e7f7d225 DH |
434 | // TODO: check d_is_whiteout(dentry) also. |
435 | return d_is_miss(dentry); | |
b18825a7 DH |
436 | } |
437 | ||
438 | static inline bool d_is_positive(const struct dentry *dentry) | |
439 | { | |
440 | return !d_is_negative(dentry); | |
441 | } | |
442 | ||
525d27b2 DH |
443 | /** |
444 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
445 | * @dentry: The dentry in question | |
446 | * | |
447 | * Returns true if the dentry represents either an absent name or a name that | |
448 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
449 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
450 | * fallthrough marker in an opaque directory. | |
451 | * | |
452 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
453 | * dentries. It should not be used to look at some other filesystem's | |
454 | * dentries. (2) It should also be used in combination with d_inode() to get | |
455 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
456 | * type field of the flags may be set to something other than miss or whiteout. | |
457 | */ | |
458 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
459 | { | |
460 | return dentry->d_inode == NULL; | |
461 | } | |
462 | ||
463 | /** | |
464 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
465 | * @dentry: The dentry in question | |
466 | * | |
467 | * Returns true if the dentry represents a name that maps to an inode | |
468 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
469 | * that is represented on medium as a 0,0 chardev. | |
470 | * | |
471 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
472 | * dentries. It should not be used to look at some other filesystem's | |
473 | * dentries. (2) It should also be used in combination with d_inode() to get | |
474 | * the inode. | |
475 | */ | |
476 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
477 | { | |
478 | return dentry->d_inode != NULL; | |
479 | } | |
480 | ||
dc3f4198 AV |
481 | static inline int simple_positive(struct dentry *dentry) |
482 | { | |
483 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
484 | } | |
485 | ||
df1a085a DH |
486 | extern void d_set_fallthru(struct dentry *dentry); |
487 | ||
488 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
489 | { | |
490 | return dentry->d_flags & DCACHE_FALLTHRU; | |
491 | } | |
492 | ||
493 | ||
1da177e4 LT |
494 | extern int sysctl_vfs_cache_pressure; |
495 | ||
55f841ce GC |
496 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
497 | { | |
498 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
499 | } | |
155e35d4 DH |
500 | |
501 | /** | |
502 | * d_inode - Get the actual inode of this dentry | |
503 | * @dentry: The dentry to query | |
504 | * | |
505 | * This is the helper normal filesystems should use to get at their own inodes | |
506 | * in their own dentries and ignore the layering superimposed upon them. | |
507 | */ | |
508 | static inline struct inode *d_inode(const struct dentry *dentry) | |
509 | { | |
510 | return dentry->d_inode; | |
511 | } | |
512 | ||
513 | /** | |
514 | * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE() | |
515 | * @dentry: The dentry to query | |
516 | * | |
517 | * This is the helper normal filesystems should use to get at their own inodes | |
518 | * in their own dentries and ignore the layering superimposed upon them. | |
519 | */ | |
520 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
521 | { | |
522 | return ACCESS_ONCE(dentry->d_inode); | |
523 | } | |
524 | ||
525 | /** | |
526 | * d_backing_inode - Get upper or lower inode we should be using | |
527 | * @upper: The upper layer | |
528 | * | |
529 | * This is the helper that should be used to get at the inode that will be used | |
530 | * if this dentry were to be opened as a file. The inode may be on the upper | |
531 | * dentry or it may be on a lower dentry pinned by the upper. | |
532 | * | |
533 | * Normal filesystems should not use this to access their own inodes. | |
534 | */ | |
535 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
536 | { | |
537 | struct inode *inode = upper->d_inode; | |
538 | ||
539 | return inode; | |
540 | } | |
541 | ||
542 | /** | |
543 | * d_backing_dentry - Get upper or lower dentry we should be using | |
544 | * @upper: The upper layer | |
545 | * | |
546 | * This is the helper that should be used to get the dentry of the inode that | |
547 | * will be used if this dentry were opened as a file. It may be the upper | |
548 | * dentry or it may be a lower dentry pinned by the upper. | |
549 | * | |
550 | * Normal filesystems should not use this to access their own dentries. | |
551 | */ | |
552 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
553 | { | |
554 | return upper; | |
555 | } | |
556 | ||
2d902671 MS |
557 | static inline struct dentry *d_real(struct dentry *dentry, |
558 | const struct inode *inode, | |
559 | unsigned int flags) | |
d101a125 MS |
560 | { |
561 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
2d902671 | 562 | return dentry->d_op->d_real(dentry, inode, flags); |
d101a125 MS |
563 | else |
564 | return dentry; | |
565 | } | |
566 | ||
a1180844 MS |
567 | /** |
568 | * d_real_inode - Return the real inode | |
569 | * @dentry: The dentry to query | |
570 | * | |
571 | * If dentry is on an union/overlay, then return the underlying, real inode. | |
572 | * Otherwise return d_inode(). | |
573 | */ | |
574 | static inline struct inode *d_real_inode(struct dentry *dentry) | |
575 | { | |
2d902671 | 576 | return d_backing_inode(d_real(dentry, NULL, 0)); |
a1180844 MS |
577 | } |
578 | ||
54d5ca87 | 579 | |
1da177e4 | 580 | #endif /* __LINUX_DCACHE_H */ |