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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef __LINUX_DCACHE_H |
3 | #define __LINUX_DCACHE_H | |
4 | ||
60063497 | 5 | #include <linux/atomic.h> |
1da177e4 | 6 | #include <linux/list.h> |
aa6159ab | 7 | #include <linux/math.h> |
82524746 | 8 | #include <linux/rculist.h> |
ceb5bdc2 | 9 | #include <linux/rculist_bl.h> |
1da177e4 | 10 | #include <linux/spinlock.h> |
31e6b01f | 11 | #include <linux/seqlock.h> |
1da177e4 LT |
12 | #include <linux/cache.h> |
13 | #include <linux/rcupdate.h> | |
98474236 | 14 | #include <linux/lockref.h> |
f4bcbe79 | 15 | #include <linux/stringhash.h> |
f9411ebe | 16 | #include <linux/wait.h> |
1da177e4 | 17 | |
cf28b486 | 18 | struct path; |
1da177e4 LT |
19 | struct vfsmount; |
20 | ||
21 | /* | |
22 | * linux/include/linux/dcache.h | |
23 | * | |
24 | * Dirent cache data structures | |
25 | * | |
26 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
27 | * with heavy changes by Linus Torvalds | |
28 | */ | |
29 | ||
30 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
31 | ||
26fe5750 LT |
32 | /* The hash is always the low bits of hash_len */ |
33 | #ifdef __LITTLE_ENDIAN | |
2bd03e49 | 34 | #define HASH_LEN_DECLARE u32 hash; u32 len |
a5c21dce | 35 | #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) |
26fe5750 | 36 | #else |
2bd03e49 | 37 | #define HASH_LEN_DECLARE u32 len; u32 hash |
a5c21dce | 38 | #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) |
26fe5750 LT |
39 | #endif |
40 | ||
1da177e4 LT |
41 | /* |
42 | * "quick string" -- eases parameter passing, but more importantly | |
43 | * saves "metadata" about the string (ie length and the hash). | |
44 | * | |
45 | * hash comes first so it snuggles against d_parent in the | |
46 | * dentry. | |
47 | */ | |
48 | struct qstr { | |
26fe5750 LT |
49 | union { |
50 | struct { | |
51 | HASH_LEN_DECLARE; | |
52 | }; | |
53 | u64 hash_len; | |
54 | }; | |
1da177e4 LT |
55 | const unsigned char *name; |
56 | }; | |
57 | ||
26fe5750 | 58 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
26fe5750 | 59 | |
cdf01226 | 60 | extern const struct qstr empty_name; |
cdf01226 | 61 | extern const struct qstr slash_name; |
80e5d1ff | 62 | extern const struct qstr dotdot_name; |
cdf01226 | 63 | |
1da177e4 | 64 | struct dentry_stat_t { |
3942c07c GC |
65 | long nr_dentry; |
66 | long nr_unused; | |
af0c9af1 WL |
67 | long age_limit; /* age in seconds */ |
68 | long want_pages; /* pages requested by system */ | |
69 | long nr_negative; /* # of unused negative dentries */ | |
70 | long dummy; /* Reserved for future use */ | |
1da177e4 LT |
71 | }; |
72 | extern struct dentry_stat_t dentry_stat; | |
73 | ||
c2452f32 NP |
74 | /* |
75 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
76 | * give reasonable cacheline footprint with larger lines without the | |
77 | * large memory footprint increase). | |
78 | */ | |
79 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 80 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 81 | #else |
44a7d7a8 NP |
82 | # ifdef CONFIG_SMP |
83 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
84 | # else | |
85 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
86 | # endif | |
c2452f32 | 87 | #endif |
1da177e4 | 88 | |
98474236 WL |
89 | #define d_lock d_lockref.lock |
90 | ||
1da177e4 | 91 | struct dentry { |
44a7d7a8 | 92 | /* RCU lookup touched fields */ |
1da177e4 | 93 | unsigned int d_flags; /* protected by d_lock */ |
26475371 | 94 | seqcount_spinlock_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 95 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
96 | struct dentry *d_parent; /* parent directory */ |
97 | struct qstr d_name; | |
44a7d7a8 NP |
98 | struct inode *d_inode; /* Where the name belongs to - NULL is |
99 | * negative */ | |
100 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
101 | ||
102 | /* Ref lookup also touches following */ | |
98474236 | 103 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
104 | const struct dentry_operations *d_op; |
105 | struct super_block *d_sb; /* The root of the dentry tree */ | |
106 | unsigned long d_time; /* used by d_revalidate */ | |
107 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 | 108 | |
d9171b93 AV |
109 | union { |
110 | struct list_head d_lru; /* LRU list */ | |
111 | wait_queue_head_t *d_wait; /* in-lookup ones only */ | |
112 | }; | |
946e51f2 AV |
113 | struct list_head d_child; /* child of parent list */ |
114 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 115 | /* |
946e51f2 | 116 | * d_alias and d_rcu can share memory |
5160ee6f ED |
117 | */ |
118 | union { | |
946e51f2 | 119 | struct hlist_node d_alias; /* inode alias list */ |
94bdd655 | 120 | struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ |
5160ee6f ED |
121 | struct rcu_head d_rcu; |
122 | } d_u; | |
3859a271 | 123 | } __randomize_layout; |
1da177e4 | 124 | |
a90b9c05 IM |
125 | /* |
126 | * dentry->d_lock spinlock nesting subclasses: | |
127 | * | |
128 | * 0: normal | |
129 | * 1: nested | |
130 | */ | |
131 | enum dentry_d_lock_class | |
132 | { | |
133 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
134 | DENTRY_D_LOCK_NESTED | |
135 | }; | |
136 | ||
1da177e4 | 137 | struct dentry_operations { |
0b728e19 | 138 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 139 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 | 140 | int (*d_hash)(const struct dentry *, struct qstr *); |
6fa67e70 | 141 | int (*d_compare)(const struct dentry *, |
621e155a | 142 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 143 | int (*d_delete)(const struct dentry *); |
285b102d | 144 | int (*d_init)(struct dentry *); |
1da177e4 | 145 | void (*d_release)(struct dentry *); |
f0023bc6 | 146 | void (*d_prune)(struct dentry *); |
1da177e4 | 147 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 148 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 149 | struct vfsmount *(*d_automount)(struct path *); |
fb5f51c7 | 150 | int (*d_manage)(const struct path *, bool); |
fb16043b | 151 | struct dentry *(*d_real)(struct dentry *, const struct inode *); |
44a7d7a8 | 152 | } ____cacheline_aligned; |
1da177e4 | 153 | |
5eef7fa9 NP |
154 | /* |
155 | * Locking rules for dentry_operations callbacks are to be found in | |
ec23eb54 | 156 | * Documentation/filesystems/locking.rst. Keep it updated! |
5eef7fa9 | 157 | * |
5c437fa2 | 158 | * FUrther descriptions are found in Documentation/filesystems/vfs.rst. |
621e155a | 159 | * Keep it updated too! |
1da177e4 LT |
160 | */ |
161 | ||
162 | /* d_flags entries */ | |
b18825a7 DH |
163 | #define DCACHE_OP_HASH 0x00000001 |
164 | #define DCACHE_OP_COMPARE 0x00000002 | |
165 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
166 | #define DCACHE_OP_DELETE 0x00000008 | |
167 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 168 | |
b18825a7 | 169 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
170 | /* This dentry is possibly not currently connected to the dcache tree, in |
171 | * which case its parent will either be itself, or will have this flag as | |
172 | * well. nfsd will not use a dentry with this bit set, but will first | |
173 | * endeavour to clear the bit either by discovering that it is connected, | |
174 | * or by performing lookup operations. Any filesystem which supports | |
175 | * nfsd_operations MUST have a lookup function which, if it finds a | |
176 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
177 | * dentry into place and return that dentry rather than the passed one, | |
178 | * typically using d_splice_alias. */ | |
1da177e4 | 179 | |
b18825a7 | 180 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
c28f7e56 | 181 | |
2c567af4 IW |
182 | #define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ |
183 | ||
b18825a7 DH |
184 | #define DCACHE_CANT_MOUNT 0x00000100 |
185 | #define DCACHE_GENOCIDE 0x00000200 | |
186 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 187 | |
b18825a7 | 188 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 189 | |
b18825a7 | 190 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
191 | /* this dentry has been "silly renamed" and has to be deleted on the last |
192 | * dput() */ | |
b18825a7 DH |
193 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
194 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 195 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 196 | |
b18825a7 DH |
197 | #define DCACHE_DENTRY_KILLED 0x00008000 |
198 | ||
199 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
200 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
201 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 202 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 203 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 204 | |
b18825a7 DH |
205 | #define DCACHE_LRU_LIST 0x00080000 |
206 | ||
207 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
208 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
209 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
210 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
211 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
212 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
213 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
214 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 215 | |
41edf278 | 216 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 217 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
501e43fb | 218 | #define DCACHE_NOKEY_NAME 0x02000000 /* Encrypted name encoded without key */ |
2d902671 | 219 | #define DCACHE_OP_REAL 0x04000000 |
0b81d077 | 220 | |
85c7f810 | 221 | #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ |
ba65dc5e | 222 | #define DCACHE_DENTRY_CURSOR 0x20000000 |
5467a68c | 223 | #define DCACHE_NORCU 0x40000000 /* No RCU delay for freeing */ |
85c7f810 | 224 | |
74c3cbe3 | 225 | extern seqlock_t rename_lock; |
1da177e4 | 226 | |
1da177e4 LT |
227 | /* |
228 | * These are the low-level FS interfaces to the dcache.. | |
229 | */ | |
230 | extern void d_instantiate(struct dentry *, struct inode *); | |
1e2e547a | 231 | extern void d_instantiate_new(struct dentry *, struct inode *); |
1da177e4 | 232 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); |
f9c34674 | 233 | extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *); |
789680d1 NP |
234 | extern void __d_drop(struct dentry *dentry); |
235 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 236 | extern void d_delete(struct dentry *); |
fb045adb | 237 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
238 | |
239 | /* allocate/de-allocate */ | |
240 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
f9c34674 | 241 | extern struct dentry * d_alloc_anon(struct super_block *); |
d9171b93 AV |
242 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
243 | wait_queue_head_t *); | |
1da177e4 | 244 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 245 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 246 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 247 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 248 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 249 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
250 | extern void shrink_dcache_sb(struct super_block *); |
251 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 252 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 253 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
254 | |
255 | /* only used at mount-time */ | |
adc0e91a | 256 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
257 | |
258 | /* <clickety>-<click> the ramfs-type tree */ | |
259 | extern void d_genocide(struct dentry *); | |
260 | ||
60545d0d AV |
261 | extern void d_tmpfile(struct dentry *, struct inode *); |
262 | ||
1da177e4 LT |
263 | extern struct dentry *d_find_alias(struct inode *); |
264 | extern void d_prune_aliases(struct inode *); | |
265 | ||
bca585d2 AV |
266 | extern struct dentry *d_find_alias_rcu(struct inode *); |
267 | ||
1da177e4 | 268 | /* test whether we have any submounts in a subdir tree */ |
01619491 | 269 | extern int path_has_submounts(const struct path *); |
1da177e4 LT |
270 | |
271 | /* | |
272 | * This adds the entry to the hash queues. | |
273 | */ | |
274 | extern void d_rehash(struct dentry *); | |
1da177e4 | 275 | |
34d0d19d | 276 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 277 | |
1da177e4 LT |
278 | /* used for rename() and baskets */ |
279 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 280 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 281 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
282 | |
283 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 284 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 285 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 286 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 287 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 288 | const struct qstr *name, unsigned *seq); |
31e6b01f | 289 | |
24924a20 | 290 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 291 | { |
98474236 | 292 | return dentry->d_lockref.count; |
84d08fa8 AV |
293 | } |
294 | ||
c23fbb6b ED |
295 | /* |
296 | * helper function for dentry_operations.d_dname() members | |
297 | */ | |
8db14860 NI |
298 | extern __printf(4, 5) |
299 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
c23fbb6b | 300 | |
02125a82 AV |
301 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
302 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 303 | extern char *d_path(const struct path *, char *, int); |
a2bbe664 AV |
304 | extern char *dentry_path_raw(const struct dentry *, char *, int); |
305 | extern char *dentry_path(const struct dentry *, char *, int); | |
cf28b486 | 306 | |
1da177e4 LT |
307 | /* Allocation counts.. */ |
308 | ||
309 | /** | |
dc0474be | 310 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
311 | * @dentry: dentry to get a reference to |
312 | * | |
313 | * Given a dentry or %NULL pointer increment the reference count | |
314 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 315 | * destroyed when it has references. |
1da177e4 | 316 | */ |
b7ab39f6 NP |
317 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
318 | { | |
dc0474be | 319 | if (dentry) |
98474236 | 320 | dentry->d_lockref.count++; |
b7ab39f6 NP |
321 | return dentry; |
322 | } | |
2fd6b7f5 | 323 | |
1da177e4 LT |
324 | static inline struct dentry *dget(struct dentry *dentry) |
325 | { | |
98474236 WL |
326 | if (dentry) |
327 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
328 | return dentry; |
329 | } | |
330 | ||
b7ab39f6 | 331 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
332 | |
333 | /** | |
334 | * d_unhashed - is dentry hashed | |
335 | * @dentry: entry to check | |
336 | * | |
337 | * Returns true if the dentry passed is not currently hashed. | |
338 | */ | |
339 | ||
f0d3b3de | 340 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 341 | { |
dea3667b | 342 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
343 | } |
344 | ||
f0d3b3de | 345 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
346 | { |
347 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
348 | } | |
349 | ||
f0d3b3de | 350 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
351 | { |
352 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
353 | } | |
354 | ||
355 | static inline void dont_mount(struct dentry *dentry) | |
356 | { | |
357 | spin_lock(&dentry->d_lock); | |
358 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
359 | spin_unlock(&dentry->d_lock); | |
360 | } | |
361 | ||
85c7f810 AV |
362 | extern void __d_lookup_done(struct dentry *); |
363 | ||
4ded097b | 364 | static inline int d_in_lookup(const struct dentry *dentry) |
85c7f810 AV |
365 | { |
366 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
367 | } | |
368 | ||
369 | static inline void d_lookup_done(struct dentry *dentry) | |
370 | { | |
371 | if (unlikely(d_in_lookup(dentry))) { | |
372 | spin_lock(&dentry->d_lock); | |
373 | __d_lookup_done(dentry); | |
374 | spin_unlock(&dentry->d_lock); | |
375 | } | |
376 | } | |
377 | ||
1da177e4 LT |
378 | extern void dput(struct dentry *); |
379 | ||
f0d3b3de | 380 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
381 | { |
382 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
383 | } | |
384 | ||
f0d3b3de | 385 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 386 | { |
5f57cbcc | 387 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
388 | } |
389 | ||
b18825a7 DH |
390 | /* |
391 | * Directory cache entry type accessor functions. | |
392 | */ | |
b18825a7 DH |
393 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
394 | { | |
a528aca7 | 395 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
396 | } |
397 | ||
e7f7d225 DH |
398 | static inline bool d_is_miss(const struct dentry *dentry) |
399 | { | |
400 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
401 | } | |
402 | ||
403 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
404 | { | |
405 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
406 | } | |
407 | ||
44b1d530 | 408 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
409 | { |
410 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
411 | } | |
412 | ||
413 | static inline bool d_is_autodir(const struct dentry *dentry) | |
414 | { | |
415 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
416 | } | |
417 | ||
44b1d530 MS |
418 | static inline bool d_is_dir(const struct dentry *dentry) |
419 | { | |
420 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
421 | } | |
422 | ||
b18825a7 DH |
423 | static inline bool d_is_symlink(const struct dentry *dentry) |
424 | { | |
425 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
426 | } | |
427 | ||
44bdb5e5 DH |
428 | static inline bool d_is_reg(const struct dentry *dentry) |
429 | { | |
430 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
431 | } | |
432 | ||
433 | static inline bool d_is_special(const struct dentry *dentry) | |
434 | { | |
435 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
436 | } | |
437 | ||
b18825a7 DH |
438 | static inline bool d_is_file(const struct dentry *dentry) |
439 | { | |
44bdb5e5 | 440 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
441 | } |
442 | ||
443 | static inline bool d_is_negative(const struct dentry *dentry) | |
444 | { | |
e7f7d225 DH |
445 | // TODO: check d_is_whiteout(dentry) also. |
446 | return d_is_miss(dentry); | |
b18825a7 DH |
447 | } |
448 | ||
d41efb52 AV |
449 | static inline bool d_flags_negative(unsigned flags) |
450 | { | |
451 | return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE; | |
452 | } | |
453 | ||
b18825a7 DH |
454 | static inline bool d_is_positive(const struct dentry *dentry) |
455 | { | |
456 | return !d_is_negative(dentry); | |
457 | } | |
458 | ||
525d27b2 DH |
459 | /** |
460 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
461 | * @dentry: The dentry in question | |
462 | * | |
463 | * Returns true if the dentry represents either an absent name or a name that | |
464 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
465 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
466 | * fallthrough marker in an opaque directory. | |
467 | * | |
468 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
469 | * dentries. It should not be used to look at some other filesystem's | |
470 | * dentries. (2) It should also be used in combination with d_inode() to get | |
471 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
472 | * type field of the flags may be set to something other than miss or whiteout. | |
473 | */ | |
474 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
475 | { | |
476 | return dentry->d_inode == NULL; | |
477 | } | |
478 | ||
479 | /** | |
480 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
481 | * @dentry: The dentry in question | |
482 | * | |
483 | * Returns true if the dentry represents a name that maps to an inode | |
484 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
485 | * that is represented on medium as a 0,0 chardev. | |
486 | * | |
487 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
488 | * dentries. It should not be used to look at some other filesystem's | |
489 | * dentries. (2) It should also be used in combination with d_inode() to get | |
490 | * the inode. | |
491 | */ | |
492 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
493 | { | |
494 | return dentry->d_inode != NULL; | |
495 | } | |
496 | ||
4ded097b | 497 | static inline int simple_positive(const struct dentry *dentry) |
dc3f4198 AV |
498 | { |
499 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
500 | } | |
501 | ||
df1a085a DH |
502 | extern void d_set_fallthru(struct dentry *dentry); |
503 | ||
504 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
505 | { | |
506 | return dentry->d_flags & DCACHE_FALLTHRU; | |
507 | } | |
508 | ||
509 | ||
1da177e4 LT |
510 | extern int sysctl_vfs_cache_pressure; |
511 | ||
55f841ce GC |
512 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
513 | { | |
514 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
515 | } | |
155e35d4 DH |
516 | |
517 | /** | |
518 | * d_inode - Get the actual inode of this dentry | |
519 | * @dentry: The dentry to query | |
520 | * | |
521 | * This is the helper normal filesystems should use to get at their own inodes | |
522 | * in their own dentries and ignore the layering superimposed upon them. | |
523 | */ | |
524 | static inline struct inode *d_inode(const struct dentry *dentry) | |
525 | { | |
526 | return dentry->d_inode; | |
527 | } | |
528 | ||
529 | /** | |
66702eb5 | 530 | * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE() |
155e35d4 DH |
531 | * @dentry: The dentry to query |
532 | * | |
533 | * This is the helper normal filesystems should use to get at their own inodes | |
534 | * in their own dentries and ignore the layering superimposed upon them. | |
535 | */ | |
536 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
537 | { | |
66702eb5 | 538 | return READ_ONCE(dentry->d_inode); |
155e35d4 DH |
539 | } |
540 | ||
541 | /** | |
542 | * d_backing_inode - Get upper or lower inode we should be using | |
543 | * @upper: The upper layer | |
544 | * | |
545 | * This is the helper that should be used to get at the inode that will be used | |
546 | * if this dentry were to be opened as a file. The inode may be on the upper | |
547 | * dentry or it may be on a lower dentry pinned by the upper. | |
548 | * | |
549 | * Normal filesystems should not use this to access their own inodes. | |
550 | */ | |
551 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
552 | { | |
553 | struct inode *inode = upper->d_inode; | |
554 | ||
555 | return inode; | |
556 | } | |
557 | ||
558 | /** | |
559 | * d_backing_dentry - Get upper or lower dentry we should be using | |
560 | * @upper: The upper layer | |
561 | * | |
562 | * This is the helper that should be used to get the dentry of the inode that | |
563 | * will be used if this dentry were opened as a file. It may be the upper | |
564 | * dentry or it may be a lower dentry pinned by the upper. | |
565 | * | |
566 | * Normal filesystems should not use this to access their own dentries. | |
567 | */ | |
568 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
569 | { | |
570 | return upper; | |
571 | } | |
572 | ||
e698b8a4 MS |
573 | /** |
574 | * d_real - Return the real dentry | |
575 | * @dentry: the dentry to query | |
576 | * @inode: inode to select the dentry from multiple layers (can be NULL) | |
e698b8a4 | 577 | * |
03440c4e | 578 | * If dentry is on a union/overlay, then return the underlying, real dentry. |
e698b8a4 MS |
579 | * Otherwise return the dentry itself. |
580 | * | |
5c437fa2 | 581 | * See also: Documentation/filesystems/vfs.rst |
e698b8a4 | 582 | */ |
2d902671 | 583 | static inline struct dentry *d_real(struct dentry *dentry, |
fb16043b | 584 | const struct inode *inode) |
d101a125 MS |
585 | { |
586 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
fb16043b | 587 | return dentry->d_op->d_real(dentry, inode); |
d101a125 MS |
588 | else |
589 | return dentry; | |
590 | } | |
591 | ||
a1180844 MS |
592 | /** |
593 | * d_real_inode - Return the real inode | |
594 | * @dentry: The dentry to query | |
595 | * | |
03440c4e | 596 | * If dentry is on a union/overlay, then return the underlying, real inode. |
a1180844 MS |
597 | * Otherwise return d_inode(). |
598 | */ | |
7b1742eb | 599 | static inline struct inode *d_real_inode(const struct dentry *dentry) |
a1180844 | 600 | { |
7b1742eb | 601 | /* This usage of d_real() results in const dentry */ |
fb16043b | 602 | return d_backing_inode(d_real((struct dentry *) dentry, NULL)); |
a1180844 MS |
603 | } |
604 | ||
49d31c2f | 605 | struct name_snapshot { |
230c6402 | 606 | struct qstr name; |
0a2c13d9 | 607 | unsigned char inline_name[DNAME_INLINE_LEN]; |
49d31c2f AV |
608 | }; |
609 | void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); | |
610 | void release_dentry_name_snapshot(struct name_snapshot *); | |
54d5ca87 | 611 | |
1da177e4 | 612 | #endif /* __LINUX_DCACHE_H */ |