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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> |
f9411ebe | 14 | #include <linux/wait.h> |
1da177e4 | 15 | |
cf28b486 | 16 | struct path; |
1da177e4 LT |
17 | struct vfsmount; |
18 | ||
19 | /* | |
20 | * linux/include/linux/dcache.h | |
21 | * | |
22 | * Dirent cache data structures | |
23 | * | |
24 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
25 | * with heavy changes by Linus Torvalds | |
26 | */ | |
27 | ||
28 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
29 | ||
26fe5750 LT |
30 | /* The hash is always the low bits of hash_len */ |
31 | #ifdef __LITTLE_ENDIAN | |
2bd03e49 | 32 | #define HASH_LEN_DECLARE u32 hash; u32 len |
a5c21dce | 33 | #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) |
26fe5750 | 34 | #else |
2bd03e49 | 35 | #define HASH_LEN_DECLARE u32 len; u32 hash |
a5c21dce | 36 | #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) |
26fe5750 LT |
37 | #endif |
38 | ||
1da177e4 LT |
39 | /* |
40 | * "quick string" -- eases parameter passing, but more importantly | |
41 | * saves "metadata" about the string (ie length and the hash). | |
42 | * | |
43 | * hash comes first so it snuggles against d_parent in the | |
44 | * dentry. | |
45 | */ | |
46 | struct qstr { | |
26fe5750 LT |
47 | union { |
48 | struct { | |
49 | HASH_LEN_DECLARE; | |
50 | }; | |
51 | u64 hash_len; | |
52 | }; | |
1da177e4 LT |
53 | const unsigned char *name; |
54 | }; | |
55 | ||
26fe5750 | 56 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
26fe5750 | 57 | |
1da177e4 | 58 | struct dentry_stat_t { |
3942c07c GC |
59 | long nr_dentry; |
60 | long nr_unused; | |
61 | long age_limit; /* age in seconds */ | |
62 | long want_pages; /* pages requested by system */ | |
63 | long dummy[2]; | |
1da177e4 LT |
64 | }; |
65 | extern struct dentry_stat_t dentry_stat; | |
66 | ||
c2452f32 NP |
67 | /* |
68 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
69 | * give reasonable cacheline footprint with larger lines without the | |
70 | * large memory footprint increase). | |
71 | */ | |
72 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 73 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 74 | #else |
44a7d7a8 NP |
75 | # ifdef CONFIG_SMP |
76 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
77 | # else | |
78 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
79 | # endif | |
c2452f32 | 80 | #endif |
1da177e4 | 81 | |
98474236 WL |
82 | #define d_lock d_lockref.lock |
83 | ||
1da177e4 | 84 | struct dentry { |
44a7d7a8 | 85 | /* RCU lookup touched fields */ |
1da177e4 | 86 | unsigned int d_flags; /* protected by d_lock */ |
31e6b01f | 87 | seqcount_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 88 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
89 | struct dentry *d_parent; /* parent directory */ |
90 | struct qstr d_name; | |
44a7d7a8 NP |
91 | struct inode *d_inode; /* Where the name belongs to - NULL is |
92 | * negative */ | |
93 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
94 | ||
95 | /* Ref lookup also touches following */ | |
98474236 | 96 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
97 | const struct dentry_operations *d_op; |
98 | struct super_block *d_sb; /* The root of the dentry tree */ | |
99 | unsigned long d_time; /* used by d_revalidate */ | |
100 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 | 101 | |
d9171b93 AV |
102 | union { |
103 | struct list_head d_lru; /* LRU list */ | |
104 | wait_queue_head_t *d_wait; /* in-lookup ones only */ | |
105 | }; | |
946e51f2 AV |
106 | struct list_head d_child; /* child of parent list */ |
107 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 108 | /* |
946e51f2 | 109 | * d_alias and d_rcu can share memory |
5160ee6f ED |
110 | */ |
111 | union { | |
946e51f2 | 112 | struct hlist_node d_alias; /* inode alias list */ |
94bdd655 | 113 | struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ |
5160ee6f ED |
114 | struct rcu_head d_rcu; |
115 | } d_u; | |
1da177e4 LT |
116 | }; |
117 | ||
a90b9c05 IM |
118 | /* |
119 | * dentry->d_lock spinlock nesting subclasses: | |
120 | * | |
121 | * 0: normal | |
122 | * 1: nested | |
123 | */ | |
124 | enum dentry_d_lock_class | |
125 | { | |
126 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
127 | DENTRY_D_LOCK_NESTED | |
128 | }; | |
129 | ||
1da177e4 | 130 | struct dentry_operations { |
0b728e19 | 131 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 132 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 | 133 | int (*d_hash)(const struct dentry *, struct qstr *); |
6fa67e70 | 134 | int (*d_compare)(const struct dentry *, |
621e155a | 135 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 136 | int (*d_delete)(const struct dentry *); |
285b102d | 137 | int (*d_init)(struct dentry *); |
1da177e4 | 138 | void (*d_release)(struct dentry *); |
f0023bc6 | 139 | void (*d_prune)(struct dentry *); |
1da177e4 | 140 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 141 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 142 | struct vfsmount *(*d_automount)(struct path *); |
fb5f51c7 | 143 | int (*d_manage)(const struct path *, bool); |
e698b8a4 MS |
144 | struct dentry *(*d_real)(struct dentry *, const struct inode *, |
145 | unsigned int); | |
44a7d7a8 | 146 | } ____cacheline_aligned; |
1da177e4 | 147 | |
5eef7fa9 NP |
148 | /* |
149 | * Locking rules for dentry_operations callbacks are to be found in | |
150 | * Documentation/filesystems/Locking. Keep it updated! | |
151 | * | |
621e155a NP |
152 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
153 | * Keep it updated too! | |
1da177e4 LT |
154 | */ |
155 | ||
156 | /* d_flags entries */ | |
b18825a7 DH |
157 | #define DCACHE_OP_HASH 0x00000001 |
158 | #define DCACHE_OP_COMPARE 0x00000002 | |
159 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
160 | #define DCACHE_OP_DELETE 0x00000008 | |
161 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 162 | |
b18825a7 | 163 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
164 | /* This dentry is possibly not currently connected to the dcache tree, in |
165 | * which case its parent will either be itself, or will have this flag as | |
166 | * well. nfsd will not use a dentry with this bit set, but will first | |
167 | * endeavour to clear the bit either by discovering that it is connected, | |
168 | * or by performing lookup operations. Any filesystem which supports | |
169 | * nfsd_operations MUST have a lookup function which, if it finds a | |
170 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
171 | * dentry into place and return that dentry rather than the passed one, | |
172 | * typically using d_splice_alias. */ | |
1da177e4 | 173 | |
b18825a7 DH |
174 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
175 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 176 | |
b18825a7 DH |
177 | #define DCACHE_CANT_MOUNT 0x00000100 |
178 | #define DCACHE_GENOCIDE 0x00000200 | |
179 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 180 | |
b18825a7 | 181 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 182 | |
b18825a7 | 183 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
184 | /* this dentry has been "silly renamed" and has to be deleted on the last |
185 | * dput() */ | |
b18825a7 DH |
186 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
187 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 188 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 189 | |
b18825a7 DH |
190 | #define DCACHE_DENTRY_KILLED 0x00008000 |
191 | ||
192 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
193 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
194 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 195 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 196 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 197 | |
b18825a7 DH |
198 | #define DCACHE_LRU_LIST 0x00080000 |
199 | ||
200 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
201 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
202 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
203 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
204 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
205 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
206 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
207 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 208 | |
41edf278 | 209 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 210 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
2d902671 MS |
211 | #define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */ |
212 | #define DCACHE_OP_REAL 0x04000000 | |
0b81d077 | 213 | |
85c7f810 | 214 | #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ |
ba65dc5e | 215 | #define DCACHE_DENTRY_CURSOR 0x20000000 |
85c7f810 | 216 | |
74c3cbe3 | 217 | extern seqlock_t rename_lock; |
1da177e4 | 218 | |
1da177e4 LT |
219 | /* |
220 | * These are the low-level FS interfaces to the dcache.. | |
221 | */ | |
222 | extern void d_instantiate(struct dentry *, struct inode *); | |
223 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
b70a80e7 | 224 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
225 | extern void __d_drop(struct dentry *dentry); |
226 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 227 | extern void d_delete(struct dentry *); |
fb045adb | 228 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
229 | |
230 | /* allocate/de-allocate */ | |
231 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 232 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
d9171b93 AV |
233 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
234 | wait_queue_head_t *); | |
1da177e4 | 235 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 236 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 237 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 238 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 239 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 240 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
241 | extern void shrink_dcache_sb(struct super_block *); |
242 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 243 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 244 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
245 | |
246 | /* only used at mount-time */ | |
adc0e91a | 247 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
248 | |
249 | /* <clickety>-<click> the ramfs-type tree */ | |
250 | extern void d_genocide(struct dentry *); | |
251 | ||
60545d0d AV |
252 | extern void d_tmpfile(struct dentry *, struct inode *); |
253 | ||
1da177e4 LT |
254 | extern struct dentry *d_find_alias(struct inode *); |
255 | extern void d_prune_aliases(struct inode *); | |
256 | ||
257 | /* test whether we have any submounts in a subdir tree */ | |
01619491 | 258 | extern int path_has_submounts(const struct path *); |
1da177e4 LT |
259 | |
260 | /* | |
261 | * This adds the entry to the hash queues. | |
262 | */ | |
263 | extern void d_rehash(struct dentry *); | |
1da177e4 | 264 | |
34d0d19d | 265 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 266 | |
9aba36de | 267 | extern void dentry_update_name_case(struct dentry *, const struct qstr *); |
fb2d5b86 | 268 | |
1da177e4 LT |
269 | /* used for rename() and baskets */ |
270 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 271 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 272 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
273 | |
274 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 275 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 276 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 277 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 278 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 279 | const struct qstr *name, unsigned *seq); |
31e6b01f | 280 | |
24924a20 | 281 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 282 | { |
98474236 | 283 | return dentry->d_lockref.count; |
84d08fa8 AV |
284 | } |
285 | ||
c23fbb6b ED |
286 | /* |
287 | * helper function for dentry_operations.d_dname() members | |
288 | */ | |
8db14860 NI |
289 | extern __printf(4, 5) |
290 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 291 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 292 | |
02125a82 AV |
293 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
294 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 295 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 296 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 297 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 298 | |
1da177e4 LT |
299 | /* Allocation counts.. */ |
300 | ||
301 | /** | |
dc0474be | 302 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
303 | * @dentry: dentry to get a reference to |
304 | * | |
305 | * Given a dentry or %NULL pointer increment the reference count | |
306 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 307 | * destroyed when it has references. |
1da177e4 | 308 | */ |
b7ab39f6 NP |
309 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
310 | { | |
dc0474be | 311 | if (dentry) |
98474236 | 312 | dentry->d_lockref.count++; |
b7ab39f6 NP |
313 | return dentry; |
314 | } | |
2fd6b7f5 | 315 | |
1da177e4 LT |
316 | static inline struct dentry *dget(struct dentry *dentry) |
317 | { | |
98474236 WL |
318 | if (dentry) |
319 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
320 | return dentry; |
321 | } | |
322 | ||
b7ab39f6 | 323 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
324 | |
325 | /** | |
326 | * d_unhashed - is dentry hashed | |
327 | * @dentry: entry to check | |
328 | * | |
329 | * Returns true if the dentry passed is not currently hashed. | |
330 | */ | |
331 | ||
f0d3b3de | 332 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 333 | { |
dea3667b | 334 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
335 | } |
336 | ||
f0d3b3de | 337 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
338 | { |
339 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
340 | } | |
341 | ||
f0d3b3de | 342 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
343 | { |
344 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
345 | } | |
346 | ||
347 | static inline void dont_mount(struct dentry *dentry) | |
348 | { | |
349 | spin_lock(&dentry->d_lock); | |
350 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
351 | spin_unlock(&dentry->d_lock); | |
352 | } | |
353 | ||
85c7f810 AV |
354 | extern void __d_lookup_done(struct dentry *); |
355 | ||
356 | static inline int d_in_lookup(struct dentry *dentry) | |
357 | { | |
358 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
359 | } | |
360 | ||
361 | static inline void d_lookup_done(struct dentry *dentry) | |
362 | { | |
363 | if (unlikely(d_in_lookup(dentry))) { | |
364 | spin_lock(&dentry->d_lock); | |
365 | __d_lookup_done(dentry); | |
366 | spin_unlock(&dentry->d_lock); | |
367 | } | |
368 | } | |
369 | ||
1da177e4 LT |
370 | extern void dput(struct dentry *); |
371 | ||
f0d3b3de | 372 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
373 | { |
374 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
375 | } | |
376 | ||
f0d3b3de | 377 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 378 | { |
5f57cbcc | 379 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
380 | } |
381 | ||
b18825a7 DH |
382 | /* |
383 | * Directory cache entry type accessor functions. | |
384 | */ | |
b18825a7 DH |
385 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
386 | { | |
a528aca7 | 387 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
388 | } |
389 | ||
e7f7d225 DH |
390 | static inline bool d_is_miss(const struct dentry *dentry) |
391 | { | |
392 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
393 | } | |
394 | ||
395 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
396 | { | |
397 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
398 | } | |
399 | ||
44b1d530 | 400 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
401 | { |
402 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
403 | } | |
404 | ||
405 | static inline bool d_is_autodir(const struct dentry *dentry) | |
406 | { | |
407 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
408 | } | |
409 | ||
44b1d530 MS |
410 | static inline bool d_is_dir(const struct dentry *dentry) |
411 | { | |
412 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
413 | } | |
414 | ||
b18825a7 DH |
415 | static inline bool d_is_symlink(const struct dentry *dentry) |
416 | { | |
417 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
418 | } | |
419 | ||
44bdb5e5 DH |
420 | static inline bool d_is_reg(const struct dentry *dentry) |
421 | { | |
422 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
423 | } | |
424 | ||
425 | static inline bool d_is_special(const struct dentry *dentry) | |
426 | { | |
427 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
428 | } | |
429 | ||
b18825a7 DH |
430 | static inline bool d_is_file(const struct dentry *dentry) |
431 | { | |
44bdb5e5 | 432 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
433 | } |
434 | ||
435 | static inline bool d_is_negative(const struct dentry *dentry) | |
436 | { | |
e7f7d225 DH |
437 | // TODO: check d_is_whiteout(dentry) also. |
438 | return d_is_miss(dentry); | |
b18825a7 DH |
439 | } |
440 | ||
441 | static inline bool d_is_positive(const struct dentry *dentry) | |
442 | { | |
443 | return !d_is_negative(dentry); | |
444 | } | |
445 | ||
525d27b2 DH |
446 | /** |
447 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
448 | * @dentry: The dentry in question | |
449 | * | |
450 | * Returns true if the dentry represents either an absent name or a name that | |
451 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
452 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
453 | * fallthrough marker in an opaque directory. | |
454 | * | |
455 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
456 | * dentries. It should not be used to look at some other filesystem's | |
457 | * dentries. (2) It should also be used in combination with d_inode() to get | |
458 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
459 | * type field of the flags may be set to something other than miss or whiteout. | |
460 | */ | |
461 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
462 | { | |
463 | return dentry->d_inode == NULL; | |
464 | } | |
465 | ||
466 | /** | |
467 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
468 | * @dentry: The dentry in question | |
469 | * | |
470 | * Returns true if the dentry represents a name that maps to an inode | |
471 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
472 | * that is represented on medium as a 0,0 chardev. | |
473 | * | |
474 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
475 | * dentries. It should not be used to look at some other filesystem's | |
476 | * dentries. (2) It should also be used in combination with d_inode() to get | |
477 | * the inode. | |
478 | */ | |
479 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
480 | { | |
481 | return dentry->d_inode != NULL; | |
482 | } | |
483 | ||
dc3f4198 AV |
484 | static inline int simple_positive(struct dentry *dentry) |
485 | { | |
486 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
487 | } | |
488 | ||
df1a085a DH |
489 | extern void d_set_fallthru(struct dentry *dentry); |
490 | ||
491 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
492 | { | |
493 | return dentry->d_flags & DCACHE_FALLTHRU; | |
494 | } | |
495 | ||
496 | ||
1da177e4 LT |
497 | extern int sysctl_vfs_cache_pressure; |
498 | ||
55f841ce GC |
499 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
500 | { | |
501 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
502 | } | |
155e35d4 DH |
503 | |
504 | /** | |
505 | * d_inode - Get the actual inode of this dentry | |
506 | * @dentry: The dentry to query | |
507 | * | |
508 | * This is the helper normal filesystems should use to get at their own inodes | |
509 | * in their own dentries and ignore the layering superimposed upon them. | |
510 | */ | |
511 | static inline struct inode *d_inode(const struct dentry *dentry) | |
512 | { | |
513 | return dentry->d_inode; | |
514 | } | |
515 | ||
516 | /** | |
517 | * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE() | |
518 | * @dentry: The dentry to query | |
519 | * | |
520 | * This is the helper normal filesystems should use to get at their own inodes | |
521 | * in their own dentries and ignore the layering superimposed upon them. | |
522 | */ | |
523 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
524 | { | |
525 | return ACCESS_ONCE(dentry->d_inode); | |
526 | } | |
527 | ||
528 | /** | |
529 | * d_backing_inode - Get upper or lower inode we should be using | |
530 | * @upper: The upper layer | |
531 | * | |
532 | * This is the helper that should be used to get at the inode that will be used | |
533 | * if this dentry were to be opened as a file. The inode may be on the upper | |
534 | * dentry or it may be on a lower dentry pinned by the upper. | |
535 | * | |
536 | * Normal filesystems should not use this to access their own inodes. | |
537 | */ | |
538 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
539 | { | |
540 | struct inode *inode = upper->d_inode; | |
541 | ||
542 | return inode; | |
543 | } | |
544 | ||
545 | /** | |
546 | * d_backing_dentry - Get upper or lower dentry we should be using | |
547 | * @upper: The upper layer | |
548 | * | |
549 | * This is the helper that should be used to get the dentry of the inode that | |
550 | * will be used if this dentry were opened as a file. It may be the upper | |
551 | * dentry or it may be a lower dentry pinned by the upper. | |
552 | * | |
553 | * Normal filesystems should not use this to access their own dentries. | |
554 | */ | |
555 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
556 | { | |
557 | return upper; | |
558 | } | |
559 | ||
e698b8a4 MS |
560 | /** |
561 | * d_real - Return the real dentry | |
562 | * @dentry: the dentry to query | |
563 | * @inode: inode to select the dentry from multiple layers (can be NULL) | |
564 | * @flags: open flags to control copy-up behavior | |
565 | * | |
03440c4e | 566 | * If dentry is on a union/overlay, then return the underlying, real dentry. |
e698b8a4 MS |
567 | * Otherwise return the dentry itself. |
568 | * | |
569 | * See also: Documentation/filesystems/vfs.txt | |
570 | */ | |
2d902671 MS |
571 | static inline struct dentry *d_real(struct dentry *dentry, |
572 | const struct inode *inode, | |
573 | unsigned int flags) | |
d101a125 MS |
574 | { |
575 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
2d902671 | 576 | return dentry->d_op->d_real(dentry, inode, flags); |
d101a125 MS |
577 | else |
578 | return dentry; | |
579 | } | |
580 | ||
a1180844 MS |
581 | /** |
582 | * d_real_inode - Return the real inode | |
583 | * @dentry: The dentry to query | |
584 | * | |
03440c4e | 585 | * If dentry is on a union/overlay, then return the underlying, real inode. |
a1180844 MS |
586 | * Otherwise return d_inode(). |
587 | */ | |
7b1742eb | 588 | static inline struct inode *d_real_inode(const struct dentry *dentry) |
a1180844 | 589 | { |
7b1742eb MS |
590 | /* This usage of d_real() results in const dentry */ |
591 | return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0)); | |
a1180844 MS |
592 | } |
593 | ||
54d5ca87 | 594 | |
1da177e4 | 595 | #endif /* __LINUX_DCACHE_H */ |