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 | 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 *); |
285b102d | 136 | int (*d_init)(struct dentry *); |
1da177e4 | 137 | void (*d_release)(struct dentry *); |
f0023bc6 | 138 | void (*d_prune)(struct dentry *); |
1da177e4 | 139 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 140 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 141 | struct vfsmount *(*d_automount)(struct path *); |
1aed3e42 | 142 | int (*d_manage)(struct dentry *, bool); |
e698b8a4 MS |
143 | struct dentry *(*d_real)(struct dentry *, const struct inode *, |
144 | unsigned int); | |
44a7d7a8 | 145 | } ____cacheline_aligned; |
1da177e4 | 146 | |
5eef7fa9 NP |
147 | /* |
148 | * Locking rules for dentry_operations callbacks are to be found in | |
149 | * Documentation/filesystems/Locking. Keep it updated! | |
150 | * | |
621e155a NP |
151 | * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
152 | * Keep it updated too! | |
1da177e4 LT |
153 | */ |
154 | ||
155 | /* d_flags entries */ | |
b18825a7 DH |
156 | #define DCACHE_OP_HASH 0x00000001 |
157 | #define DCACHE_OP_COMPARE 0x00000002 | |
158 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
159 | #define DCACHE_OP_DELETE 0x00000008 | |
160 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 161 | |
b18825a7 | 162 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
163 | /* This dentry is possibly not currently connected to the dcache tree, in |
164 | * which case its parent will either be itself, or will have this flag as | |
165 | * well. nfsd will not use a dentry with this bit set, but will first | |
166 | * endeavour to clear the bit either by discovering that it is connected, | |
167 | * or by performing lookup operations. Any filesystem which supports | |
168 | * nfsd_operations MUST have a lookup function which, if it finds a | |
169 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
170 | * dentry into place and return that dentry rather than the passed one, | |
171 | * typically using d_splice_alias. */ | |
1da177e4 | 172 | |
b18825a7 DH |
173 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
174 | #define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */ | |
c28f7e56 | 175 | |
b18825a7 DH |
176 | #define DCACHE_CANT_MOUNT 0x00000100 |
177 | #define DCACHE_GENOCIDE 0x00000200 | |
178 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 179 | |
b18825a7 | 180 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 181 | |
b18825a7 | 182 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
183 | /* this dentry has been "silly renamed" and has to be deleted on the last |
184 | * dput() */ | |
b18825a7 DH |
185 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
186 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 187 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 188 | |
b18825a7 DH |
189 | #define DCACHE_DENTRY_KILLED 0x00008000 |
190 | ||
191 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
192 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
193 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 194 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 195 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 196 | |
b18825a7 DH |
197 | #define DCACHE_LRU_LIST 0x00080000 |
198 | ||
199 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
200 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
201 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
202 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
203 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
204 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
205 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
206 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 207 | |
41edf278 | 208 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 209 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
2d902671 MS |
210 | #define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */ |
211 | #define DCACHE_OP_REAL 0x04000000 | |
0b81d077 | 212 | |
85c7f810 | 213 | #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ |
ba65dc5e | 214 | #define DCACHE_DENTRY_CURSOR 0x20000000 |
85c7f810 | 215 | |
74c3cbe3 | 216 | extern seqlock_t rename_lock; |
1da177e4 | 217 | |
1da177e4 LT |
218 | /* |
219 | * These are the low-level FS interfaces to the dcache.. | |
220 | */ | |
221 | extern void d_instantiate(struct dentry *, struct inode *); | |
222 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); | |
b70a80e7 | 223 | extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |
789680d1 NP |
224 | extern void __d_drop(struct dentry *dentry); |
225 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 226 | extern void d_delete(struct dentry *); |
fb045adb | 227 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
228 | |
229 | /* allocate/de-allocate */ | |
230 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
4b936885 | 231 | extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
d9171b93 AV |
232 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
233 | wait_queue_head_t *); | |
1da177e4 | 234 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 235 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 236 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 237 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 238 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 239 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
240 | extern void shrink_dcache_sb(struct super_block *); |
241 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 242 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 243 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
244 | |
245 | /* only used at mount-time */ | |
adc0e91a | 246 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
247 | |
248 | /* <clickety>-<click> the ramfs-type tree */ | |
249 | extern void d_genocide(struct dentry *); | |
250 | ||
60545d0d AV |
251 | extern void d_tmpfile(struct dentry *, struct inode *); |
252 | ||
1da177e4 LT |
253 | extern struct dentry *d_find_alias(struct inode *); |
254 | extern void d_prune_aliases(struct inode *); | |
255 | ||
256 | /* test whether we have any submounts in a subdir tree */ | |
257 | extern int have_submounts(struct dentry *); | |
258 | ||
259 | /* | |
260 | * This adds the entry to the hash queues. | |
261 | */ | |
262 | extern void d_rehash(struct dentry *); | |
1da177e4 | 263 | |
34d0d19d | 264 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 265 | |
9aba36de | 266 | extern void dentry_update_name_case(struct dentry *, const struct qstr *); |
fb2d5b86 | 267 | |
1da177e4 LT |
268 | /* used for rename() and baskets */ |
269 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 270 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 271 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
272 | |
273 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 274 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 275 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 276 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 277 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 278 | const struct qstr *name, unsigned *seq); |
31e6b01f | 279 | |
24924a20 | 280 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 281 | { |
98474236 | 282 | return dentry->d_lockref.count; |
84d08fa8 AV |
283 | } |
284 | ||
c23fbb6b ED |
285 | /* |
286 | * helper function for dentry_operations.d_dname() members | |
287 | */ | |
8db14860 NI |
288 | extern __printf(4, 5) |
289 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
118b2302 | 290 | extern char *simple_dname(struct dentry *, char *, int); |
c23fbb6b | 291 | |
02125a82 AV |
292 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
293 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 294 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 295 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 296 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 297 | |
1da177e4 LT |
298 | /* Allocation counts.. */ |
299 | ||
300 | /** | |
dc0474be | 301 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
302 | * @dentry: dentry to get a reference to |
303 | * | |
304 | * Given a dentry or %NULL pointer increment the reference count | |
305 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 306 | * destroyed when it has references. |
1da177e4 | 307 | */ |
b7ab39f6 NP |
308 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
309 | { | |
dc0474be | 310 | if (dentry) |
98474236 | 311 | dentry->d_lockref.count++; |
b7ab39f6 NP |
312 | return dentry; |
313 | } | |
2fd6b7f5 | 314 | |
1da177e4 LT |
315 | static inline struct dentry *dget(struct dentry *dentry) |
316 | { | |
98474236 WL |
317 | if (dentry) |
318 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
319 | return dentry; |
320 | } | |
321 | ||
b7ab39f6 | 322 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
323 | |
324 | /** | |
325 | * d_unhashed - is dentry hashed | |
326 | * @dentry: entry to check | |
327 | * | |
328 | * Returns true if the dentry passed is not currently hashed. | |
329 | */ | |
330 | ||
f0d3b3de | 331 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 332 | { |
dea3667b | 333 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
334 | } |
335 | ||
f0d3b3de | 336 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
337 | { |
338 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
339 | } | |
340 | ||
f0d3b3de | 341 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
342 | { |
343 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
344 | } | |
345 | ||
346 | static inline void dont_mount(struct dentry *dentry) | |
347 | { | |
348 | spin_lock(&dentry->d_lock); | |
349 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
350 | spin_unlock(&dentry->d_lock); | |
351 | } | |
352 | ||
85c7f810 AV |
353 | extern void __d_lookup_done(struct dentry *); |
354 | ||
355 | static inline int d_in_lookup(struct dentry *dentry) | |
356 | { | |
357 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
358 | } | |
359 | ||
360 | static inline void d_lookup_done(struct dentry *dentry) | |
361 | { | |
362 | if (unlikely(d_in_lookup(dentry))) { | |
363 | spin_lock(&dentry->d_lock); | |
364 | __d_lookup_done(dentry); | |
365 | spin_unlock(&dentry->d_lock); | |
366 | } | |
367 | } | |
368 | ||
1da177e4 LT |
369 | extern void dput(struct dentry *); |
370 | ||
f0d3b3de | 371 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
372 | { |
373 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
374 | } | |
375 | ||
f0d3b3de | 376 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 377 | { |
5f57cbcc | 378 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
379 | } |
380 | ||
b18825a7 DH |
381 | /* |
382 | * Directory cache entry type accessor functions. | |
383 | */ | |
b18825a7 DH |
384 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
385 | { | |
a528aca7 | 386 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
387 | } |
388 | ||
e7f7d225 DH |
389 | static inline bool d_is_miss(const struct dentry *dentry) |
390 | { | |
391 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
392 | } | |
393 | ||
394 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
395 | { | |
396 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
397 | } | |
398 | ||
44b1d530 | 399 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
400 | { |
401 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
402 | } | |
403 | ||
404 | static inline bool d_is_autodir(const struct dentry *dentry) | |
405 | { | |
406 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
407 | } | |
408 | ||
44b1d530 MS |
409 | static inline bool d_is_dir(const struct dentry *dentry) |
410 | { | |
411 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
412 | } | |
413 | ||
b18825a7 DH |
414 | static inline bool d_is_symlink(const struct dentry *dentry) |
415 | { | |
416 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
417 | } | |
418 | ||
44bdb5e5 DH |
419 | static inline bool d_is_reg(const struct dentry *dentry) |
420 | { | |
421 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
422 | } | |
423 | ||
424 | static inline bool d_is_special(const struct dentry *dentry) | |
425 | { | |
426 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
427 | } | |
428 | ||
b18825a7 DH |
429 | static inline bool d_is_file(const struct dentry *dentry) |
430 | { | |
44bdb5e5 | 431 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
432 | } |
433 | ||
434 | static inline bool d_is_negative(const struct dentry *dentry) | |
435 | { | |
e7f7d225 DH |
436 | // TODO: check d_is_whiteout(dentry) also. |
437 | return d_is_miss(dentry); | |
b18825a7 DH |
438 | } |
439 | ||
440 | static inline bool d_is_positive(const struct dentry *dentry) | |
441 | { | |
442 | return !d_is_negative(dentry); | |
443 | } | |
444 | ||
525d27b2 DH |
445 | /** |
446 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
447 | * @dentry: The dentry in question | |
448 | * | |
449 | * Returns true if the dentry represents either an absent name or a name that | |
450 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
451 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
452 | * fallthrough marker in an opaque directory. | |
453 | * | |
454 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
455 | * dentries. It should not be used to look at some other filesystem's | |
456 | * dentries. (2) It should also be used in combination with d_inode() to get | |
457 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
458 | * type field of the flags may be set to something other than miss or whiteout. | |
459 | */ | |
460 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
461 | { | |
462 | return dentry->d_inode == NULL; | |
463 | } | |
464 | ||
465 | /** | |
466 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
467 | * @dentry: The dentry in question | |
468 | * | |
469 | * Returns true if the dentry represents a name that maps to an inode | |
470 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
471 | * that is represented on medium as a 0,0 chardev. | |
472 | * | |
473 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
474 | * dentries. It should not be used to look at some other filesystem's | |
475 | * dentries. (2) It should also be used in combination with d_inode() to get | |
476 | * the inode. | |
477 | */ | |
478 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
479 | { | |
480 | return dentry->d_inode != NULL; | |
481 | } | |
482 | ||
dc3f4198 AV |
483 | static inline int simple_positive(struct dentry *dentry) |
484 | { | |
485 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
486 | } | |
487 | ||
df1a085a DH |
488 | extern void d_set_fallthru(struct dentry *dentry); |
489 | ||
490 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
491 | { | |
492 | return dentry->d_flags & DCACHE_FALLTHRU; | |
493 | } | |
494 | ||
495 | ||
1da177e4 LT |
496 | extern int sysctl_vfs_cache_pressure; |
497 | ||
55f841ce GC |
498 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
499 | { | |
500 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
501 | } | |
155e35d4 DH |
502 | |
503 | /** | |
504 | * d_inode - Get the actual inode of this dentry | |
505 | * @dentry: The dentry to query | |
506 | * | |
507 | * This is the helper normal filesystems should use to get at their own inodes | |
508 | * in their own dentries and ignore the layering superimposed upon them. | |
509 | */ | |
510 | static inline struct inode *d_inode(const struct dentry *dentry) | |
511 | { | |
512 | return dentry->d_inode; | |
513 | } | |
514 | ||
515 | /** | |
516 | * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE() | |
517 | * @dentry: The dentry to query | |
518 | * | |
519 | * This is the helper normal filesystems should use to get at their own inodes | |
520 | * in their own dentries and ignore the layering superimposed upon them. | |
521 | */ | |
522 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
523 | { | |
524 | return ACCESS_ONCE(dentry->d_inode); | |
525 | } | |
526 | ||
527 | /** | |
528 | * d_backing_inode - Get upper or lower inode we should be using | |
529 | * @upper: The upper layer | |
530 | * | |
531 | * This is the helper that should be used to get at the inode that will be used | |
532 | * if this dentry were to be opened as a file. The inode may be on the upper | |
533 | * dentry or it may be on a lower dentry pinned by the upper. | |
534 | * | |
535 | * Normal filesystems should not use this to access their own inodes. | |
536 | */ | |
537 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
538 | { | |
539 | struct inode *inode = upper->d_inode; | |
540 | ||
541 | return inode; | |
542 | } | |
543 | ||
544 | /** | |
545 | * d_backing_dentry - Get upper or lower dentry we should be using | |
546 | * @upper: The upper layer | |
547 | * | |
548 | * This is the helper that should be used to get the dentry of the inode that | |
549 | * will be used if this dentry were opened as a file. It may be the upper | |
550 | * dentry or it may be a lower dentry pinned by the upper. | |
551 | * | |
552 | * Normal filesystems should not use this to access their own dentries. | |
553 | */ | |
554 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
555 | { | |
556 | return upper; | |
557 | } | |
558 | ||
e698b8a4 MS |
559 | /** |
560 | * d_real - Return the real dentry | |
561 | * @dentry: the dentry to query | |
562 | * @inode: inode to select the dentry from multiple layers (can be NULL) | |
563 | * @flags: open flags to control copy-up behavior | |
564 | * | |
565 | * If dentry is on an union/overlay, then return the underlying, real dentry. | |
566 | * Otherwise return the dentry itself. | |
567 | * | |
568 | * See also: Documentation/filesystems/vfs.txt | |
569 | */ | |
2d902671 MS |
570 | static inline struct dentry *d_real(struct dentry *dentry, |
571 | const struct inode *inode, | |
572 | unsigned int flags) | |
d101a125 MS |
573 | { |
574 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
2d902671 | 575 | return dentry->d_op->d_real(dentry, inode, flags); |
d101a125 MS |
576 | else |
577 | return dentry; | |
578 | } | |
579 | ||
a1180844 MS |
580 | /** |
581 | * d_real_inode - Return the real inode | |
582 | * @dentry: The dentry to query | |
583 | * | |
584 | * If dentry is on an union/overlay, then return the underlying, real inode. | |
585 | * Otherwise return d_inode(). | |
586 | */ | |
587 | static inline struct inode *d_real_inode(struct dentry *dentry) | |
588 | { | |
2d902671 | 589 | return d_backing_inode(d_real(dentry, NULL, 0)); |
a1180844 MS |
590 | } |
591 | ||
54d5ca87 | 592 | |
1da177e4 | 593 | #endif /* __LINUX_DCACHE_H */ |