Commit | Line | Data |
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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; |
863f144f | 19 | struct file; |
1da177e4 LT |
20 | struct vfsmount; |
21 | ||
22 | /* | |
23 | * linux/include/linux/dcache.h | |
24 | * | |
25 | * Dirent cache data structures | |
26 | * | |
27 | * (C) Copyright 1997 Thomas Schoebel-Theuer, | |
28 | * with heavy changes by Linus Torvalds | |
29 | */ | |
30 | ||
31 | #define IS_ROOT(x) ((x) == (x)->d_parent) | |
32 | ||
26fe5750 LT |
33 | /* The hash is always the low bits of hash_len */ |
34 | #ifdef __LITTLE_ENDIAN | |
2bd03e49 | 35 | #define HASH_LEN_DECLARE u32 hash; u32 len |
a5c21dce | 36 | #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8)) |
26fe5750 | 37 | #else |
2bd03e49 | 38 | #define HASH_LEN_DECLARE u32 len; u32 hash |
a5c21dce | 39 | #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8)) |
26fe5750 LT |
40 | #endif |
41 | ||
1da177e4 LT |
42 | /* |
43 | * "quick string" -- eases parameter passing, but more importantly | |
44 | * saves "metadata" about the string (ie length and the hash). | |
45 | * | |
46 | * hash comes first so it snuggles against d_parent in the | |
47 | * dentry. | |
48 | */ | |
49 | struct qstr { | |
26fe5750 LT |
50 | union { |
51 | struct { | |
52 | HASH_LEN_DECLARE; | |
53 | }; | |
54 | u64 hash_len; | |
55 | }; | |
1da177e4 LT |
56 | const unsigned char *name; |
57 | }; | |
58 | ||
26fe5750 | 59 | #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } |
26fe5750 | 60 | |
cdf01226 | 61 | extern const struct qstr empty_name; |
cdf01226 | 62 | extern const struct qstr slash_name; |
80e5d1ff | 63 | extern const struct qstr dotdot_name; |
cdf01226 | 64 | |
c2452f32 NP |
65 | /* |
66 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
67 | * give reasonable cacheline footprint with larger lines without the | |
68 | * large memory footprint increase). | |
69 | */ | |
70 | #ifdef CONFIG_64BIT | |
da549bdd | 71 | # define DNAME_INLINE_LEN 40 /* 192 bytes */ |
c2452f32 | 72 | #else |
44a7d7a8 | 73 | # ifdef CONFIG_SMP |
44a7d7a8 | 74 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ |
da549bdd AV |
75 | # else |
76 | # define DNAME_INLINE_LEN 44 /* 128 bytes */ | |
44a7d7a8 | 77 | # endif |
c2452f32 | 78 | #endif |
1da177e4 | 79 | |
98474236 WL |
80 | #define d_lock d_lockref.lock |
81 | ||
1da177e4 | 82 | struct dentry { |
44a7d7a8 | 83 | /* RCU lookup touched fields */ |
1da177e4 | 84 | unsigned int d_flags; /* protected by d_lock */ |
26475371 | 85 | seqcount_spinlock_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 86 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
87 | struct dentry *d_parent; /* parent directory */ |
88 | struct qstr d_name; | |
44a7d7a8 NP |
89 | struct inode *d_inode; /* Where the name belongs to - NULL is |
90 | * negative */ | |
91 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
92 | ||
93 | /* Ref lookup also touches following */ | |
98474236 | 94 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
95 | const struct dentry_operations *d_op; |
96 | struct super_block *d_sb; /* The root of the dentry tree */ | |
97 | unsigned long d_time; /* used by d_revalidate */ | |
98 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 | 99 | |
d9171b93 AV |
100 | union { |
101 | struct list_head d_lru; /* LRU list */ | |
102 | wait_queue_head_t *d_wait; /* in-lookup ones only */ | |
103 | }; | |
da549bdd AV |
104 | struct hlist_node d_sib; /* child of parent list */ |
105 | struct hlist_head d_children; /* our children */ | |
5160ee6f | 106 | /* |
946e51f2 | 107 | * d_alias and d_rcu can share memory |
5160ee6f ED |
108 | */ |
109 | union { | |
946e51f2 | 110 | struct hlist_node d_alias; /* inode alias list */ |
94bdd655 | 111 | struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ |
5160ee6f ED |
112 | struct rcu_head d_rcu; |
113 | } d_u; | |
acfde6e8 | 114 | }; |
1da177e4 | 115 | |
a90b9c05 IM |
116 | /* |
117 | * dentry->d_lock spinlock nesting subclasses: | |
118 | * | |
119 | * 0: normal | |
120 | * 1: nested | |
121 | */ | |
122 | enum dentry_d_lock_class | |
123 | { | |
124 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
125 | DENTRY_D_LOCK_NESTED | |
126 | }; | |
127 | ||
11b3f8ae AG |
128 | enum d_real_type { |
129 | D_REAL_DATA, | |
130 | D_REAL_METADATA, | |
131 | }; | |
132 | ||
1da177e4 | 133 | struct dentry_operations { |
0b728e19 | 134 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 135 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 | 136 | int (*d_hash)(const struct dentry *, struct qstr *); |
6fa67e70 | 137 | int (*d_compare)(const struct dentry *, |
621e155a | 138 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 139 | int (*d_delete)(const struct dentry *); |
285b102d | 140 | int (*d_init)(struct dentry *); |
1da177e4 | 141 | void (*d_release)(struct dentry *); |
f0023bc6 | 142 | void (*d_prune)(struct dentry *); |
1da177e4 | 143 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 144 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 145 | struct vfsmount *(*d_automount)(struct path *); |
fb5f51c7 | 146 | int (*d_manage)(const struct path *, bool); |
11b3f8ae | 147 | struct dentry *(*d_real)(struct dentry *, enum d_real_type type); |
44a7d7a8 | 148 | } ____cacheline_aligned; |
1da177e4 | 149 | |
5eef7fa9 NP |
150 | /* |
151 | * Locking rules for dentry_operations callbacks are to be found in | |
ec23eb54 | 152 | * Documentation/filesystems/locking.rst. Keep it updated! |
5eef7fa9 | 153 | * |
5c437fa2 | 154 | * FUrther descriptions are found in Documentation/filesystems/vfs.rst. |
621e155a | 155 | * Keep it updated too! |
1da177e4 LT |
156 | */ |
157 | ||
158 | /* d_flags entries */ | |
641c3ef5 AV |
159 | #define DCACHE_OP_HASH BIT(0) |
160 | #define DCACHE_OP_COMPARE BIT(1) | |
161 | #define DCACHE_OP_REVALIDATE BIT(2) | |
162 | #define DCACHE_OP_DELETE BIT(3) | |
163 | #define DCACHE_OP_PRUNE BIT(4) | |
5f57cbcc | 164 | |
641c3ef5 | 165 | #define DCACHE_DISCONNECTED BIT(5) |
5f57cbcc NP |
166 | /* This dentry is possibly not currently connected to the dcache tree, in |
167 | * which case its parent will either be itself, or will have this flag as | |
168 | * well. nfsd will not use a dentry with this bit set, but will first | |
169 | * endeavour to clear the bit either by discovering that it is connected, | |
170 | * or by performing lookup operations. Any filesystem which supports | |
171 | * nfsd_operations MUST have a lookup function which, if it finds a | |
172 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
173 | * dentry into place and return that dentry rather than the passed one, | |
174 | * typically using d_splice_alias. */ | |
1da177e4 | 175 | |
641c3ef5 | 176 | #define DCACHE_REFERENCED BIT(6) /* Recently used, don't discard. */ |
c28f7e56 | 177 | |
641c3ef5 | 178 | #define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */ |
2c567af4 | 179 | |
641c3ef5 | 180 | #define DCACHE_CANT_MOUNT BIT(8) |
7e4a205f | 181 | #define DCACHE_GENOCIDE BIT(9) |
641c3ef5 | 182 | #define DCACHE_SHRINK_LIST BIT(10) |
5f57cbcc | 183 | |
641c3ef5 | 184 | #define DCACHE_OP_WEAK_REVALIDATE BIT(11) |
ecf3d1f1 | 185 | |
641c3ef5 | 186 | #define DCACHE_NFSFS_RENAMED BIT(12) |
830c0f0e LT |
187 | /* this dentry has been "silly renamed" and has to be deleted on the last |
188 | * dput() */ | |
641c3ef5 | 189 | #define DCACHE_FSNOTIFY_PARENT_WATCHED BIT(14) |
830c0f0e | 190 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 191 | |
641c3ef5 | 192 | #define DCACHE_DENTRY_KILLED BIT(15) |
b18825a7 | 193 | |
641c3ef5 AV |
194 | #define DCACHE_MOUNTED BIT(16) /* is a mountpoint */ |
195 | #define DCACHE_NEED_AUTOMOUNT BIT(17) /* handle automount on this dir */ | |
196 | #define DCACHE_MANAGE_TRANSIT BIT(18) /* manage transit from this dirent */ | |
9875cf80 | 197 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 198 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 199 | |
641c3ef5 AV |
200 | #define DCACHE_LRU_LIST BIT(19) |
201 | ||
202 | #define DCACHE_ENTRY_TYPE (7 << 20) /* bits 20..22 are for storing type: */ | |
8219cb58 | 203 | #define DCACHE_MISS_TYPE (0 << 20) /* Negative dentry */ |
641c3ef5 AV |
204 | #define DCACHE_WHITEOUT_TYPE (1 << 20) /* Whiteout dentry (stop pathwalk) */ |
205 | #define DCACHE_DIRECTORY_TYPE (2 << 20) /* Normal directory */ | |
206 | #define DCACHE_AUTODIR_TYPE (3 << 20) /* Lookupless directory (presumed automount) */ | |
8219cb58 AV |
207 | #define DCACHE_REGULAR_TYPE (4 << 20) /* Regular file type */ |
208 | #define DCACHE_SPECIAL_TYPE (5 << 20) /* Other file type */ | |
209 | #define DCACHE_SYMLINK_TYPE (6 << 20) /* Symlink */ | |
641c3ef5 | 210 | |
641c3ef5 AV |
211 | #define DCACHE_NOKEY_NAME BIT(25) /* Encrypted name encoded without key */ |
212 | #define DCACHE_OP_REAL BIT(26) | |
213 | ||
214 | #define DCACHE_PAR_LOOKUP BIT(28) /* being looked up (with parent locked shared) */ | |
215 | #define DCACHE_DENTRY_CURSOR BIT(29) | |
216 | #define DCACHE_NORCU BIT(30) /* No RCU delay for freeing */ | |
85c7f810 | 217 | |
74c3cbe3 | 218 | extern seqlock_t rename_lock; |
1da177e4 | 219 | |
1da177e4 LT |
220 | /* |
221 | * These are the low-level FS interfaces to the dcache.. | |
222 | */ | |
223 | extern void d_instantiate(struct dentry *, struct inode *); | |
1e2e547a | 224 | extern void d_instantiate_new(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 *); | |
f9c34674 | 232 | extern struct dentry * d_alloc_anon(struct super_block *); |
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 *); |
4f48d5da XL |
237 | extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent, |
238 | const struct qstr *name); | |
668d0cd5 | 239 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 240 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 241 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 242 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
243 | extern void shrink_dcache_sb(struct super_block *); |
244 | extern void shrink_dcache_parent(struct dentry *); | |
5542aa2f | 245 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
246 | |
247 | /* only used at mount-time */ | |
adc0e91a | 248 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 | 249 | |
771eb4fe | 250 | extern void d_mark_tmpfile(struct file *, struct inode *); |
863f144f | 251 | extern void d_tmpfile(struct file *, struct inode *); |
60545d0d | 252 | |
1da177e4 LT |
253 | extern struct dentry *d_find_alias(struct inode *); |
254 | extern void d_prune_aliases(struct inode *); | |
255 | ||
bca585d2 AV |
256 | extern struct dentry *d_find_alias_rcu(struct inode *); |
257 | ||
1da177e4 | 258 | /* test whether we have any submounts in a subdir tree */ |
01619491 | 259 | extern int path_has_submounts(const struct path *); |
1da177e4 LT |
260 | |
261 | /* | |
262 | * This adds the entry to the hash queues. | |
263 | */ | |
264 | extern void d_rehash(struct dentry *); | |
1da177e4 | 265 | |
34d0d19d | 266 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 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 | 272 | |
da2d8455 | 273 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 274 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
31e6b01f | 275 | |
24924a20 | 276 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 277 | { |
98474236 | 278 | return dentry->d_lockref.count; |
84d08fa8 AV |
279 | } |
280 | ||
c23fbb6b ED |
281 | /* |
282 | * helper function for dentry_operations.d_dname() members | |
283 | */ | |
0f60d288 AV |
284 | extern __printf(3, 4) |
285 | char *dynamic_dname(char *, int, const char *, ...); | |
c23fbb6b | 286 | |
02125a82 AV |
287 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
288 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 289 | extern char *d_path(const struct path *, char *, int); |
a2bbe664 AV |
290 | extern char *dentry_path_raw(const struct dentry *, char *, int); |
291 | extern char *dentry_path(const struct dentry *, char *, int); | |
cf28b486 | 292 | |
1da177e4 LT |
293 | /* Allocation counts.. */ |
294 | ||
295 | /** | |
1b6ae9f6 VN |
296 | * dget_dlock - get a reference to a dentry |
297 | * @dentry: dentry to get a reference to | |
1da177e4 | 298 | * |
1b6ae9f6 VN |
299 | * Given a live dentry, increment the reference count and return the dentry. |
300 | * Caller must hold @dentry->d_lock. Making sure that dentry is alive is | |
301 | * caller's resonsibility. There are many conditions sufficient to guarantee | |
302 | * that; e.g. anything with non-negative refcount is alive, so's anything | |
303 | * hashed, anything positive, anyone's parent, etc. | |
1da177e4 | 304 | */ |
b7ab39f6 NP |
305 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
306 | { | |
1b6ae9f6 | 307 | dentry->d_lockref.count++; |
b7ab39f6 NP |
308 | return dentry; |
309 | } | |
2fd6b7f5 | 310 | |
1b6ae9f6 VN |
311 | |
312 | /** | |
313 | * dget - get a reference to a dentry | |
314 | * @dentry: dentry to get a reference to | |
315 | * | |
316 | * Given a dentry or %NULL pointer increment the reference count | |
317 | * if appropriate and return the dentry. A dentry will not be | |
318 | * destroyed when it has references. Conversely, a dentry with | |
319 | * no references can disappear for any number of reasons, starting | |
320 | * with memory pressure. In other words, that primitive is | |
321 | * used to clone an existing reference; using it on something with | |
322 | * zero refcount is a bug. | |
323 | * | |
324 | * NOTE: it will spin if @dentry->d_lock is held. From the deadlock | |
325 | * avoidance point of view it is equivalent to spin_lock()/increment | |
326 | * refcount/spin_unlock(), so calling it under @dentry->d_lock is | |
327 | * always a bug; so's calling it under ->d_lock on any of its descendents. | |
328 | * | |
329 | */ | |
1da177e4 LT |
330 | static inline struct dentry *dget(struct dentry *dentry) |
331 | { | |
98474236 WL |
332 | if (dentry) |
333 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
334 | return dentry; |
335 | } | |
336 | ||
b7ab39f6 | 337 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
338 | |
339 | /** | |
1b6ae9f6 VN |
340 | * d_unhashed - is dentry hashed |
341 | * @dentry: entry to check | |
1da177e4 | 342 | * |
1b6ae9f6 | 343 | * Returns true if the dentry passed is not currently hashed. |
1da177e4 | 344 | */ |
f0d3b3de | 345 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 346 | { |
dea3667b | 347 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
348 | } |
349 | ||
f0d3b3de | 350 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
351 | { |
352 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
353 | } | |
354 | ||
f0d3b3de | 355 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
356 | { |
357 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
358 | } | |
359 | ||
360 | static inline void dont_mount(struct dentry *dentry) | |
361 | { | |
362 | spin_lock(&dentry->d_lock); | |
363 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
364 | spin_unlock(&dentry->d_lock); | |
365 | } | |
366 | ||
45f78b0a | 367 | extern void __d_lookup_unhash_wake(struct dentry *dentry); |
85c7f810 | 368 | |
4ded097b | 369 | static inline int d_in_lookup(const struct dentry *dentry) |
85c7f810 AV |
370 | { |
371 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
372 | } | |
373 | ||
374 | static inline void d_lookup_done(struct dentry *dentry) | |
375 | { | |
45f78b0a SAS |
376 | if (unlikely(d_in_lookup(dentry))) |
377 | __d_lookup_unhash_wake(dentry); | |
85c7f810 AV |
378 | } |
379 | ||
1da177e4 LT |
380 | extern void dput(struct dentry *); |
381 | ||
f0d3b3de | 382 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
383 | { |
384 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
385 | } | |
386 | ||
f0d3b3de | 387 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 388 | { |
5f57cbcc | 389 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
390 | } |
391 | ||
b18825a7 DH |
392 | /* |
393 | * Directory cache entry type accessor functions. | |
394 | */ | |
b18825a7 DH |
395 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
396 | { | |
a528aca7 | 397 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
398 | } |
399 | ||
e7f7d225 DH |
400 | static inline bool d_is_miss(const struct dentry *dentry) |
401 | { | |
402 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
403 | } | |
404 | ||
405 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
406 | { | |
407 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
408 | } | |
409 | ||
44b1d530 | 410 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
411 | { |
412 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
413 | } | |
414 | ||
415 | static inline bool d_is_autodir(const struct dentry *dentry) | |
416 | { | |
417 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
418 | } | |
419 | ||
44b1d530 MS |
420 | static inline bool d_is_dir(const struct dentry *dentry) |
421 | { | |
422 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
423 | } | |
424 | ||
b18825a7 DH |
425 | static inline bool d_is_symlink(const struct dentry *dentry) |
426 | { | |
427 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
428 | } | |
429 | ||
44bdb5e5 DH |
430 | static inline bool d_is_reg(const struct dentry *dentry) |
431 | { | |
432 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
433 | } | |
434 | ||
435 | static inline bool d_is_special(const struct dentry *dentry) | |
436 | { | |
437 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
438 | } | |
439 | ||
b18825a7 DH |
440 | static inline bool d_is_file(const struct dentry *dentry) |
441 | { | |
44bdb5e5 | 442 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
443 | } |
444 | ||
445 | static inline bool d_is_negative(const struct dentry *dentry) | |
446 | { | |
e7f7d225 DH |
447 | // TODO: check d_is_whiteout(dentry) also. |
448 | return d_is_miss(dentry); | |
b18825a7 DH |
449 | } |
450 | ||
d41efb52 AV |
451 | static inline bool d_flags_negative(unsigned flags) |
452 | { | |
453 | return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE; | |
454 | } | |
455 | ||
b18825a7 DH |
456 | static inline bool d_is_positive(const struct dentry *dentry) |
457 | { | |
458 | return !d_is_negative(dentry); | |
459 | } | |
460 | ||
525d27b2 DH |
461 | /** |
462 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
463 | * @dentry: The dentry in question | |
464 | * | |
465 | * Returns true if the dentry represents either an absent name or a name that | |
466 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
467 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
468 | * fallthrough marker in an opaque directory. | |
469 | * | |
470 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
471 | * dentries. It should not be used to look at some other filesystem's | |
472 | * dentries. (2) It should also be used in combination with d_inode() to get | |
473 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
474 | * type field of the flags may be set to something other than miss or whiteout. | |
475 | */ | |
476 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
477 | { | |
478 | return dentry->d_inode == NULL; | |
479 | } | |
480 | ||
481 | /** | |
482 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
483 | * @dentry: The dentry in question | |
484 | * | |
485 | * Returns true if the dentry represents a name that maps to an inode | |
486 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
487 | * that is represented on medium as a 0,0 chardev. | |
488 | * | |
489 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
490 | * dentries. It should not be used to look at some other filesystem's | |
491 | * dentries. (2) It should also be used in combination with d_inode() to get | |
492 | * the inode. | |
493 | */ | |
494 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
495 | { | |
496 | return dentry->d_inode != NULL; | |
497 | } | |
498 | ||
4ded097b | 499 | static inline int simple_positive(const struct dentry *dentry) |
dc3f4198 AV |
500 | { |
501 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
502 | } | |
503 | ||
1da177e4 LT |
504 | extern int sysctl_vfs_cache_pressure; |
505 | ||
55f841ce GC |
506 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
507 | { | |
508 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
509 | } | |
155e35d4 DH |
510 | |
511 | /** | |
512 | * d_inode - Get the actual inode of this dentry | |
513 | * @dentry: The dentry to query | |
514 | * | |
515 | * This is the helper normal filesystems should use to get at their own inodes | |
516 | * in their own dentries and ignore the layering superimposed upon them. | |
517 | */ | |
518 | static inline struct inode *d_inode(const struct dentry *dentry) | |
519 | { | |
520 | return dentry->d_inode; | |
521 | } | |
522 | ||
523 | /** | |
66702eb5 | 524 | * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE() |
155e35d4 DH |
525 | * @dentry: The dentry to query |
526 | * | |
527 | * This is the helper normal filesystems should use to get at their own inodes | |
528 | * in their own dentries and ignore the layering superimposed upon them. | |
529 | */ | |
530 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
531 | { | |
66702eb5 | 532 | return READ_ONCE(dentry->d_inode); |
155e35d4 DH |
533 | } |
534 | ||
535 | /** | |
536 | * d_backing_inode - Get upper or lower inode we should be using | |
537 | * @upper: The upper layer | |
538 | * | |
539 | * This is the helper that should be used to get at the inode that will be used | |
540 | * if this dentry were to be opened as a file. The inode may be on the upper | |
541 | * dentry or it may be on a lower dentry pinned by the upper. | |
542 | * | |
543 | * Normal filesystems should not use this to access their own inodes. | |
544 | */ | |
545 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
546 | { | |
547 | struct inode *inode = upper->d_inode; | |
548 | ||
549 | return inode; | |
550 | } | |
551 | ||
e698b8a4 MS |
552 | /** |
553 | * d_real - Return the real dentry | |
554 | * @dentry: the dentry to query | |
11b3f8ae | 555 | * @type: the type of real dentry (data or metadata) |
e698b8a4 | 556 | * |
03440c4e | 557 | * If dentry is on a union/overlay, then return the underlying, real dentry. |
e698b8a4 MS |
558 | * Otherwise return the dentry itself. |
559 | * | |
5c437fa2 | 560 | * See also: Documentation/filesystems/vfs.rst |
e698b8a4 | 561 | */ |
11b3f8ae | 562 | static inline struct dentry *d_real(struct dentry *dentry, enum d_real_type type) |
d101a125 MS |
563 | { |
564 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
11b3f8ae | 565 | return dentry->d_op->d_real(dentry, type); |
d101a125 MS |
566 | else |
567 | return dentry; | |
568 | } | |
569 | ||
a1180844 | 570 | /** |
11b3f8ae | 571 | * d_real_inode - Return the real inode hosting the data |
a1180844 MS |
572 | * @dentry: The dentry to query |
573 | * | |
03440c4e | 574 | * If dentry is on a union/overlay, then return the underlying, real inode. |
a1180844 MS |
575 | * Otherwise return d_inode(). |
576 | */ | |
7b1742eb | 577 | static inline struct inode *d_real_inode(const struct dentry *dentry) |
a1180844 | 578 | { |
7b1742eb | 579 | /* This usage of d_real() results in const dentry */ |
11b3f8ae | 580 | return d_inode(d_real((struct dentry *) dentry, D_REAL_DATA)); |
a1180844 MS |
581 | } |
582 | ||
49d31c2f | 583 | struct name_snapshot { |
230c6402 | 584 | struct qstr name; |
0a2c13d9 | 585 | unsigned char inline_name[DNAME_INLINE_LEN]; |
49d31c2f AV |
586 | }; |
587 | void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); | |
588 | void release_dentry_name_snapshot(struct name_snapshot *); | |
54d5ca87 | 589 | |
da549bdd AV |
590 | static inline struct dentry *d_first_child(const struct dentry *dentry) |
591 | { | |
592 | return hlist_entry_safe(dentry->d_children.first, struct dentry, d_sib); | |
593 | } | |
594 | ||
595 | static inline struct dentry *d_next_sibling(const struct dentry *dentry) | |
596 | { | |
597 | return hlist_entry_safe(dentry->d_sib.next, struct dentry, d_sib); | |
598 | } | |
599 | ||
1da177e4 | 600 | #endif /* __LINUX_DCACHE_H */ |