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; |
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 DH |
61 | extern const struct qstr slash_name; |
62 | ||
1da177e4 | 63 | struct dentry_stat_t { |
3942c07c GC |
64 | long nr_dentry; |
65 | long nr_unused; | |
af0c9af1 WL |
66 | long age_limit; /* age in seconds */ |
67 | long want_pages; /* pages requested by system */ | |
68 | long nr_negative; /* # of unused negative dentries */ | |
69 | long dummy; /* Reserved for future use */ | |
1da177e4 LT |
70 | }; |
71 | extern struct dentry_stat_t dentry_stat; | |
72 | ||
c2452f32 NP |
73 | /* |
74 | * Try to keep struct dentry aligned on 64 byte cachelines (this will | |
75 | * give reasonable cacheline footprint with larger lines without the | |
76 | * large memory footprint increase). | |
77 | */ | |
78 | #ifdef CONFIG_64BIT | |
44a7d7a8 | 79 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 80 | #else |
44a7d7a8 NP |
81 | # ifdef CONFIG_SMP |
82 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
83 | # else | |
84 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
85 | # endif | |
c2452f32 | 86 | #endif |
1da177e4 | 87 | |
98474236 WL |
88 | #define d_lock d_lockref.lock |
89 | ||
1da177e4 | 90 | struct dentry { |
44a7d7a8 | 91 | /* RCU lookup touched fields */ |
1da177e4 | 92 | unsigned int d_flags; /* protected by d_lock */ |
26475371 | 93 | seqcount_spinlock_t d_seq; /* per dentry seqlock */ |
ceb5bdc2 | 94 | struct hlist_bl_node d_hash; /* lookup hash list */ |
1da177e4 LT |
95 | struct dentry *d_parent; /* parent directory */ |
96 | struct qstr d_name; | |
44a7d7a8 NP |
97 | struct inode *d_inode; /* Where the name belongs to - NULL is |
98 | * negative */ | |
99 | unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ | |
100 | ||
101 | /* Ref lookup also touches following */ | |
98474236 | 102 | struct lockref d_lockref; /* per-dentry lock and refcount */ |
44a7d7a8 NP |
103 | const struct dentry_operations *d_op; |
104 | struct super_block *d_sb; /* The root of the dentry tree */ | |
105 | unsigned long d_time; /* used by d_revalidate */ | |
106 | void *d_fsdata; /* fs-specific data */ | |
1da177e4 | 107 | |
d9171b93 AV |
108 | union { |
109 | struct list_head d_lru; /* LRU list */ | |
110 | wait_queue_head_t *d_wait; /* in-lookup ones only */ | |
111 | }; | |
946e51f2 AV |
112 | struct list_head d_child; /* child of parent list */ |
113 | struct list_head d_subdirs; /* our children */ | |
5160ee6f | 114 | /* |
946e51f2 | 115 | * d_alias and d_rcu can share memory |
5160ee6f ED |
116 | */ |
117 | union { | |
946e51f2 | 118 | struct hlist_node d_alias; /* inode alias list */ |
94bdd655 | 119 | struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ |
5160ee6f ED |
120 | struct rcu_head d_rcu; |
121 | } d_u; | |
3859a271 | 122 | } __randomize_layout; |
1da177e4 | 123 | |
a90b9c05 IM |
124 | /* |
125 | * dentry->d_lock spinlock nesting subclasses: | |
126 | * | |
127 | * 0: normal | |
128 | * 1: nested | |
129 | */ | |
130 | enum dentry_d_lock_class | |
131 | { | |
132 | DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ | |
133 | DENTRY_D_LOCK_NESTED | |
134 | }; | |
135 | ||
1da177e4 | 136 | struct dentry_operations { |
0b728e19 | 137 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 138 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 | 139 | int (*d_hash)(const struct dentry *, struct qstr *); |
6fa67e70 | 140 | int (*d_compare)(const struct dentry *, |
621e155a | 141 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 142 | int (*d_delete)(const struct dentry *); |
285b102d | 143 | int (*d_init)(struct dentry *); |
1da177e4 | 144 | void (*d_release)(struct dentry *); |
f0023bc6 | 145 | void (*d_prune)(struct dentry *); |
1da177e4 | 146 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 147 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 148 | struct vfsmount *(*d_automount)(struct path *); |
fb5f51c7 | 149 | int (*d_manage)(const struct path *, bool); |
fb16043b | 150 | struct dentry *(*d_real)(struct dentry *, const struct inode *); |
44a7d7a8 | 151 | } ____cacheline_aligned; |
1da177e4 | 152 | |
5eef7fa9 NP |
153 | /* |
154 | * Locking rules for dentry_operations callbacks are to be found in | |
ec23eb54 | 155 | * Documentation/filesystems/locking.rst. Keep it updated! |
5eef7fa9 | 156 | * |
5c437fa2 | 157 | * FUrther descriptions are found in Documentation/filesystems/vfs.rst. |
621e155a | 158 | * Keep it updated too! |
1da177e4 LT |
159 | */ |
160 | ||
161 | /* d_flags entries */ | |
b18825a7 DH |
162 | #define DCACHE_OP_HASH 0x00000001 |
163 | #define DCACHE_OP_COMPARE 0x00000002 | |
164 | #define DCACHE_OP_REVALIDATE 0x00000004 | |
165 | #define DCACHE_OP_DELETE 0x00000008 | |
166 | #define DCACHE_OP_PRUNE 0x00000010 | |
5f57cbcc | 167 | |
b18825a7 | 168 | #define DCACHE_DISCONNECTED 0x00000020 |
5f57cbcc NP |
169 | /* This dentry is possibly not currently connected to the dcache tree, in |
170 | * which case its parent will either be itself, or will have this flag as | |
171 | * well. nfsd will not use a dentry with this bit set, but will first | |
172 | * endeavour to clear the bit either by discovering that it is connected, | |
173 | * or by performing lookup operations. Any filesystem which supports | |
174 | * nfsd_operations MUST have a lookup function which, if it finds a | |
175 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
176 | * dentry into place and return that dentry rather than the passed one, | |
177 | * typically using d_splice_alias. */ | |
1da177e4 | 178 | |
b18825a7 | 179 | #define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */ |
c28f7e56 | 180 | |
2c567af4 IW |
181 | #define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ |
182 | ||
b18825a7 DH |
183 | #define DCACHE_CANT_MOUNT 0x00000100 |
184 | #define DCACHE_GENOCIDE 0x00000200 | |
185 | #define DCACHE_SHRINK_LIST 0x00000400 | |
5f57cbcc | 186 | |
b18825a7 | 187 | #define DCACHE_OP_WEAK_REVALIDATE 0x00000800 |
ecf3d1f1 | 188 | |
b18825a7 | 189 | #define DCACHE_NFSFS_RENAMED 0x00001000 |
830c0f0e LT |
190 | /* this dentry has been "silly renamed" and has to be deleted on the last |
191 | * dput() */ | |
b18825a7 DH |
192 | #define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ |
193 | #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 | |
830c0f0e | 194 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 195 | |
b18825a7 DH |
196 | #define DCACHE_DENTRY_KILLED 0x00008000 |
197 | ||
198 | #define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ | |
199 | #define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ | |
200 | #define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */ | |
9875cf80 | 201 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 202 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 203 | |
b18825a7 DH |
204 | #define DCACHE_LRU_LIST 0x00080000 |
205 | ||
206 | #define DCACHE_ENTRY_TYPE 0x00700000 | |
e7f7d225 DH |
207 | #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ |
208 | #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ | |
209 | #define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ | |
210 | #define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ | |
44bdb5e5 DH |
211 | #define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ |
212 | #define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ | |
213 | #define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ | |
b161dfa6 | 214 | |
41edf278 | 215 | #define DCACHE_MAY_FREE 0x00800000 |
df1a085a | 216 | #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ |
501e43fb | 217 | #define DCACHE_NOKEY_NAME 0x02000000 /* Encrypted name encoded without key */ |
2d902671 | 218 | #define DCACHE_OP_REAL 0x04000000 |
0b81d077 | 219 | |
85c7f810 | 220 | #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ |
ba65dc5e | 221 | #define DCACHE_DENTRY_CURSOR 0x20000000 |
5467a68c | 222 | #define DCACHE_NORCU 0x40000000 /* No RCU delay for freeing */ |
85c7f810 | 223 | |
74c3cbe3 | 224 | extern seqlock_t rename_lock; |
1da177e4 | 225 | |
1da177e4 LT |
226 | /* |
227 | * These are the low-level FS interfaces to the dcache.. | |
228 | */ | |
229 | extern void d_instantiate(struct dentry *, struct inode *); | |
1e2e547a | 230 | extern void d_instantiate_new(struct dentry *, struct inode *); |
1da177e4 | 231 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); |
f9c34674 | 232 | extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *); |
789680d1 NP |
233 | extern void __d_drop(struct dentry *dentry); |
234 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 235 | extern void d_delete(struct dentry *); |
fb045adb | 236 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
237 | |
238 | /* allocate/de-allocate */ | |
239 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
f9c34674 | 240 | extern struct dentry * d_alloc_anon(struct super_block *); |
d9171b93 AV |
241 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
242 | wait_queue_head_t *); | |
1da177e4 | 243 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 244 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
668d0cd5 | 245 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 246 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 247 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 248 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
249 | extern void shrink_dcache_sb(struct super_block *); |
250 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 251 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 252 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
253 | |
254 | /* only used at mount-time */ | |
adc0e91a | 255 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
256 | |
257 | /* <clickety>-<click> the ramfs-type tree */ | |
258 | extern void d_genocide(struct dentry *); | |
259 | ||
60545d0d AV |
260 | extern void d_tmpfile(struct dentry *, struct inode *); |
261 | ||
1da177e4 LT |
262 | extern struct dentry *d_find_alias(struct inode *); |
263 | extern void d_prune_aliases(struct inode *); | |
264 | ||
265 | /* test whether we have any submounts in a subdir tree */ | |
01619491 | 266 | extern int path_has_submounts(const struct path *); |
1da177e4 LT |
267 | |
268 | /* | |
269 | * This adds the entry to the hash queues. | |
270 | */ | |
271 | extern void d_rehash(struct dentry *); | |
1da177e4 | 272 | |
34d0d19d | 273 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 274 | |
1da177e4 LT |
275 | /* used for rename() and baskets */ |
276 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 277 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 278 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
279 | |
280 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 281 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 282 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 283 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 284 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 285 | const struct qstr *name, unsigned *seq); |
31e6b01f | 286 | |
24924a20 | 287 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 288 | { |
98474236 | 289 | return dentry->d_lockref.count; |
84d08fa8 AV |
290 | } |
291 | ||
c23fbb6b ED |
292 | /* |
293 | * helper function for dentry_operations.d_dname() members | |
294 | */ | |
8db14860 NI |
295 | extern __printf(4, 5) |
296 | char *dynamic_dname(struct dentry *, char *, int, const char *, ...); | |
c23fbb6b | 297 | |
02125a82 AV |
298 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
299 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 300 | extern char *d_path(const struct path *, char *, int); |
ec2447c2 | 301 | extern char *dentry_path_raw(struct dentry *, char *, int); |
6092d048 | 302 | extern char *dentry_path(struct dentry *, char *, int); |
cf28b486 | 303 | |
1da177e4 LT |
304 | /* Allocation counts.. */ |
305 | ||
306 | /** | |
dc0474be | 307 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
308 | * @dentry: dentry to get a reference to |
309 | * | |
310 | * Given a dentry or %NULL pointer increment the reference count | |
311 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 312 | * destroyed when it has references. |
1da177e4 | 313 | */ |
b7ab39f6 NP |
314 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
315 | { | |
dc0474be | 316 | if (dentry) |
98474236 | 317 | dentry->d_lockref.count++; |
b7ab39f6 NP |
318 | return dentry; |
319 | } | |
2fd6b7f5 | 320 | |
1da177e4 LT |
321 | static inline struct dentry *dget(struct dentry *dentry) |
322 | { | |
98474236 WL |
323 | if (dentry) |
324 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
325 | return dentry; |
326 | } | |
327 | ||
b7ab39f6 | 328 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
329 | |
330 | /** | |
331 | * d_unhashed - is dentry hashed | |
332 | * @dentry: entry to check | |
333 | * | |
334 | * Returns true if the dentry passed is not currently hashed. | |
335 | */ | |
336 | ||
f0d3b3de | 337 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 338 | { |
dea3667b | 339 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
340 | } |
341 | ||
f0d3b3de | 342 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
343 | { |
344 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
345 | } | |
346 | ||
f0d3b3de | 347 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
348 | { |
349 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
350 | } | |
351 | ||
352 | static inline void dont_mount(struct dentry *dentry) | |
353 | { | |
354 | spin_lock(&dentry->d_lock); | |
355 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
356 | spin_unlock(&dentry->d_lock); | |
357 | } | |
358 | ||
85c7f810 AV |
359 | extern void __d_lookup_done(struct dentry *); |
360 | ||
4ded097b | 361 | static inline int d_in_lookup(const struct dentry *dentry) |
85c7f810 AV |
362 | { |
363 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
364 | } | |
365 | ||
366 | static inline void d_lookup_done(struct dentry *dentry) | |
367 | { | |
368 | if (unlikely(d_in_lookup(dentry))) { | |
369 | spin_lock(&dentry->d_lock); | |
370 | __d_lookup_done(dentry); | |
371 | spin_unlock(&dentry->d_lock); | |
372 | } | |
373 | } | |
374 | ||
1da177e4 LT |
375 | extern void dput(struct dentry *); |
376 | ||
f0d3b3de | 377 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
378 | { |
379 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
380 | } | |
381 | ||
f0d3b3de | 382 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 383 | { |
5f57cbcc | 384 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
385 | } |
386 | ||
b18825a7 DH |
387 | /* |
388 | * Directory cache entry type accessor functions. | |
389 | */ | |
b18825a7 DH |
390 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
391 | { | |
a528aca7 | 392 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
393 | } |
394 | ||
e7f7d225 DH |
395 | static inline bool d_is_miss(const struct dentry *dentry) |
396 | { | |
397 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
398 | } | |
399 | ||
400 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
401 | { | |
402 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
403 | } | |
404 | ||
44b1d530 | 405 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
406 | { |
407 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
408 | } | |
409 | ||
410 | static inline bool d_is_autodir(const struct dentry *dentry) | |
411 | { | |
412 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
413 | } | |
414 | ||
44b1d530 MS |
415 | static inline bool d_is_dir(const struct dentry *dentry) |
416 | { | |
417 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
418 | } | |
419 | ||
b18825a7 DH |
420 | static inline bool d_is_symlink(const struct dentry *dentry) |
421 | { | |
422 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
423 | } | |
424 | ||
44bdb5e5 DH |
425 | static inline bool d_is_reg(const struct dentry *dentry) |
426 | { | |
427 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
428 | } | |
429 | ||
430 | static inline bool d_is_special(const struct dentry *dentry) | |
431 | { | |
432 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
433 | } | |
434 | ||
b18825a7 DH |
435 | static inline bool d_is_file(const struct dentry *dentry) |
436 | { | |
44bdb5e5 | 437 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
438 | } |
439 | ||
440 | static inline bool d_is_negative(const struct dentry *dentry) | |
441 | { | |
e7f7d225 DH |
442 | // TODO: check d_is_whiteout(dentry) also. |
443 | return d_is_miss(dentry); | |
b18825a7 DH |
444 | } |
445 | ||
d41efb52 AV |
446 | static inline bool d_flags_negative(unsigned flags) |
447 | { | |
448 | return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE; | |
449 | } | |
450 | ||
b18825a7 DH |
451 | static inline bool d_is_positive(const struct dentry *dentry) |
452 | { | |
453 | return !d_is_negative(dentry); | |
454 | } | |
455 | ||
525d27b2 DH |
456 | /** |
457 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
458 | * @dentry: The dentry in question | |
459 | * | |
460 | * Returns true if the dentry represents either an absent name or a name that | |
461 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
462 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
463 | * fallthrough marker in an opaque directory. | |
464 | * | |
465 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
466 | * dentries. It should not be used to look at some other filesystem's | |
467 | * dentries. (2) It should also be used in combination with d_inode() to get | |
468 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
469 | * type field of the flags may be set to something other than miss or whiteout. | |
470 | */ | |
471 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
472 | { | |
473 | return dentry->d_inode == NULL; | |
474 | } | |
475 | ||
476 | /** | |
477 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
478 | * @dentry: The dentry in question | |
479 | * | |
480 | * Returns true if the dentry represents a name that maps to an inode | |
481 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
482 | * that is represented on medium as a 0,0 chardev. | |
483 | * | |
484 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
485 | * dentries. It should not be used to look at some other filesystem's | |
486 | * dentries. (2) It should also be used in combination with d_inode() to get | |
487 | * the inode. | |
488 | */ | |
489 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
490 | { | |
491 | return dentry->d_inode != NULL; | |
492 | } | |
493 | ||
4ded097b | 494 | static inline int simple_positive(const struct dentry *dentry) |
dc3f4198 AV |
495 | { |
496 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
497 | } | |
498 | ||
df1a085a DH |
499 | extern void d_set_fallthru(struct dentry *dentry); |
500 | ||
501 | static inline bool d_is_fallthru(const struct dentry *dentry) | |
502 | { | |
503 | return dentry->d_flags & DCACHE_FALLTHRU; | |
504 | } | |
505 | ||
506 | ||
1da177e4 LT |
507 | extern int sysctl_vfs_cache_pressure; |
508 | ||
55f841ce GC |
509 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
510 | { | |
511 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
512 | } | |
155e35d4 DH |
513 | |
514 | /** | |
515 | * d_inode - Get the actual inode of this dentry | |
516 | * @dentry: The dentry to query | |
517 | * | |
518 | * This is the helper normal filesystems should use to get at their own inodes | |
519 | * in their own dentries and ignore the layering superimposed upon them. | |
520 | */ | |
521 | static inline struct inode *d_inode(const struct dentry *dentry) | |
522 | { | |
523 | return dentry->d_inode; | |
524 | } | |
525 | ||
526 | /** | |
66702eb5 | 527 | * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE() |
155e35d4 DH |
528 | * @dentry: The dentry to query |
529 | * | |
530 | * This is the helper normal filesystems should use to get at their own inodes | |
531 | * in their own dentries and ignore the layering superimposed upon them. | |
532 | */ | |
533 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
534 | { | |
66702eb5 | 535 | return READ_ONCE(dentry->d_inode); |
155e35d4 DH |
536 | } |
537 | ||
538 | /** | |
539 | * d_backing_inode - Get upper or lower inode we should be using | |
540 | * @upper: The upper layer | |
541 | * | |
542 | * This is the helper that should be used to get at the inode that will be used | |
543 | * if this dentry were to be opened as a file. The inode may be on the upper | |
544 | * dentry or it may be on a lower dentry pinned by the upper. | |
545 | * | |
546 | * Normal filesystems should not use this to access their own inodes. | |
547 | */ | |
548 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
549 | { | |
550 | struct inode *inode = upper->d_inode; | |
551 | ||
552 | return inode; | |
553 | } | |
554 | ||
555 | /** | |
556 | * d_backing_dentry - Get upper or lower dentry we should be using | |
557 | * @upper: The upper layer | |
558 | * | |
559 | * This is the helper that should be used to get the dentry of the inode that | |
560 | * will be used if this dentry were opened as a file. It may be the upper | |
561 | * dentry or it may be a lower dentry pinned by the upper. | |
562 | * | |
563 | * Normal filesystems should not use this to access their own dentries. | |
564 | */ | |
565 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
566 | { | |
567 | return upper; | |
568 | } | |
569 | ||
e698b8a4 MS |
570 | /** |
571 | * d_real - Return the real dentry | |
572 | * @dentry: the dentry to query | |
573 | * @inode: inode to select the dentry from multiple layers (can be NULL) | |
e698b8a4 | 574 | * |
03440c4e | 575 | * If dentry is on a union/overlay, then return the underlying, real dentry. |
e698b8a4 MS |
576 | * Otherwise return the dentry itself. |
577 | * | |
5c437fa2 | 578 | * See also: Documentation/filesystems/vfs.rst |
e698b8a4 | 579 | */ |
2d902671 | 580 | static inline struct dentry *d_real(struct dentry *dentry, |
fb16043b | 581 | const struct inode *inode) |
d101a125 MS |
582 | { |
583 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
fb16043b | 584 | return dentry->d_op->d_real(dentry, inode); |
d101a125 MS |
585 | else |
586 | return dentry; | |
587 | } | |
588 | ||
a1180844 MS |
589 | /** |
590 | * d_real_inode - Return the real inode | |
591 | * @dentry: The dentry to query | |
592 | * | |
03440c4e | 593 | * If dentry is on a union/overlay, then return the underlying, real inode. |
a1180844 MS |
594 | * Otherwise return d_inode(). |
595 | */ | |
7b1742eb | 596 | static inline struct inode *d_real_inode(const struct dentry *dentry) |
a1180844 | 597 | { |
7b1742eb | 598 | /* This usage of d_real() results in const dentry */ |
fb16043b | 599 | return d_backing_inode(d_real((struct dentry *) dentry, NULL)); |
a1180844 MS |
600 | } |
601 | ||
49d31c2f | 602 | struct name_snapshot { |
230c6402 | 603 | struct qstr name; |
0a2c13d9 | 604 | unsigned char inline_name[DNAME_INLINE_LEN]; |
49d31c2f AV |
605 | }; |
606 | void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); | |
607 | void release_dentry_name_snapshot(struct name_snapshot *); | |
54d5ca87 | 608 | |
1da177e4 | 609 | #endif /* __LINUX_DCACHE_H */ |