Commit | Line | Data |
---|---|---|
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 | |
44a7d7a8 | 71 | # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
c2452f32 | 72 | #else |
44a7d7a8 NP |
73 | # ifdef CONFIG_SMP |
74 | # define DNAME_INLINE_LEN 36 /* 128 bytes */ | |
75 | # else | |
76 | # define DNAME_INLINE_LEN 40 /* 128 bytes */ | |
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 | }; | |
946e51f2 AV |
104 | struct list_head d_child; /* child of parent list */ |
105 | struct list_head d_subdirs; /* 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 | ||
1da177e4 | 128 | struct dentry_operations { |
0b728e19 | 129 | int (*d_revalidate)(struct dentry *, unsigned int); |
ecf3d1f1 | 130 | int (*d_weak_revalidate)(struct dentry *, unsigned int); |
da53be12 | 131 | int (*d_hash)(const struct dentry *, struct qstr *); |
6fa67e70 | 132 | int (*d_compare)(const struct dentry *, |
621e155a | 133 | unsigned int, const char *, const struct qstr *); |
fe15ce44 | 134 | int (*d_delete)(const struct dentry *); |
285b102d | 135 | int (*d_init)(struct dentry *); |
1da177e4 | 136 | void (*d_release)(struct dentry *); |
f0023bc6 | 137 | void (*d_prune)(struct dentry *); |
1da177e4 | 138 | void (*d_iput)(struct dentry *, struct inode *); |
c23fbb6b | 139 | char *(*d_dname)(struct dentry *, char *, int); |
9875cf80 | 140 | struct vfsmount *(*d_automount)(struct path *); |
fb5f51c7 | 141 | int (*d_manage)(const struct path *, bool); |
fb16043b | 142 | struct dentry *(*d_real)(struct dentry *, const struct inode *); |
44a7d7a8 | 143 | } ____cacheline_aligned; |
1da177e4 | 144 | |
5eef7fa9 NP |
145 | /* |
146 | * Locking rules for dentry_operations callbacks are to be found in | |
ec23eb54 | 147 | * Documentation/filesystems/locking.rst. Keep it updated! |
5eef7fa9 | 148 | * |
5c437fa2 | 149 | * FUrther descriptions are found in Documentation/filesystems/vfs.rst. |
621e155a | 150 | * Keep it updated too! |
1da177e4 LT |
151 | */ |
152 | ||
153 | /* d_flags entries */ | |
641c3ef5 AV |
154 | #define DCACHE_OP_HASH BIT(0) |
155 | #define DCACHE_OP_COMPARE BIT(1) | |
156 | #define DCACHE_OP_REVALIDATE BIT(2) | |
157 | #define DCACHE_OP_DELETE BIT(3) | |
158 | #define DCACHE_OP_PRUNE BIT(4) | |
5f57cbcc | 159 | |
641c3ef5 | 160 | #define DCACHE_DISCONNECTED BIT(5) |
5f57cbcc NP |
161 | /* This dentry is possibly not currently connected to the dcache tree, in |
162 | * which case its parent will either be itself, or will have this flag as | |
163 | * well. nfsd will not use a dentry with this bit set, but will first | |
164 | * endeavour to clear the bit either by discovering that it is connected, | |
165 | * or by performing lookup operations. Any filesystem which supports | |
166 | * nfsd_operations MUST have a lookup function which, if it finds a | |
167 | * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that | |
168 | * dentry into place and return that dentry rather than the passed one, | |
169 | * typically using d_splice_alias. */ | |
1da177e4 | 170 | |
641c3ef5 | 171 | #define DCACHE_REFERENCED BIT(6) /* Recently used, don't discard. */ |
c28f7e56 | 172 | |
641c3ef5 | 173 | #define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */ |
2c567af4 | 174 | |
641c3ef5 AV |
175 | #define DCACHE_CANT_MOUNT BIT(8) |
176 | #define DCACHE_GENOCIDE BIT(9) | |
177 | #define DCACHE_SHRINK_LIST BIT(10) | |
5f57cbcc | 178 | |
641c3ef5 | 179 | #define DCACHE_OP_WEAK_REVALIDATE BIT(11) |
ecf3d1f1 | 180 | |
641c3ef5 | 181 | #define DCACHE_NFSFS_RENAMED BIT(12) |
830c0f0e LT |
182 | /* this dentry has been "silly renamed" and has to be deleted on the last |
183 | * dput() */ | |
641c3ef5 | 184 | #define DCACHE_FSNOTIFY_PARENT_WATCHED BIT(14) |
830c0f0e | 185 | /* Parent inode is watched by some fsnotify listener */ |
fb045adb | 186 | |
641c3ef5 | 187 | #define DCACHE_DENTRY_KILLED BIT(15) |
b18825a7 | 188 | |
641c3ef5 AV |
189 | #define DCACHE_MOUNTED BIT(16) /* is a mountpoint */ |
190 | #define DCACHE_NEED_AUTOMOUNT BIT(17) /* handle automount on this dir */ | |
191 | #define DCACHE_MANAGE_TRANSIT BIT(18) /* manage transit from this dirent */ | |
9875cf80 | 192 | #define DCACHE_MANAGED_DENTRY \ |
cc53ce53 | 193 | (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
9875cf80 | 194 | |
641c3ef5 AV |
195 | #define DCACHE_LRU_LIST BIT(19) |
196 | ||
197 | #define DCACHE_ENTRY_TYPE (7 << 20) /* bits 20..22 are for storing type: */ | |
8219cb58 | 198 | #define DCACHE_MISS_TYPE (0 << 20) /* Negative dentry */ |
641c3ef5 AV |
199 | #define DCACHE_WHITEOUT_TYPE (1 << 20) /* Whiteout dentry (stop pathwalk) */ |
200 | #define DCACHE_DIRECTORY_TYPE (2 << 20) /* Normal directory */ | |
201 | #define DCACHE_AUTODIR_TYPE (3 << 20) /* Lookupless directory (presumed automount) */ | |
8219cb58 AV |
202 | #define DCACHE_REGULAR_TYPE (4 << 20) /* Regular file type */ |
203 | #define DCACHE_SPECIAL_TYPE (5 << 20) /* Other file type */ | |
204 | #define DCACHE_SYMLINK_TYPE (6 << 20) /* Symlink */ | |
641c3ef5 AV |
205 | |
206 | #define DCACHE_MAY_FREE BIT(23) | |
641c3ef5 AV |
207 | #define DCACHE_NOKEY_NAME BIT(25) /* Encrypted name encoded without key */ |
208 | #define DCACHE_OP_REAL BIT(26) | |
209 | ||
210 | #define DCACHE_PAR_LOOKUP BIT(28) /* being looked up (with parent locked shared) */ | |
211 | #define DCACHE_DENTRY_CURSOR BIT(29) | |
212 | #define DCACHE_NORCU BIT(30) /* No RCU delay for freeing */ | |
85c7f810 | 213 | |
74c3cbe3 | 214 | extern seqlock_t rename_lock; |
1da177e4 | 215 | |
1da177e4 LT |
216 | /* |
217 | * These are the low-level FS interfaces to the dcache.. | |
218 | */ | |
219 | extern void d_instantiate(struct dentry *, struct inode *); | |
1e2e547a | 220 | extern void d_instantiate_new(struct dentry *, struct inode *); |
1da177e4 | 221 | extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); |
f9c34674 | 222 | extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *); |
789680d1 NP |
223 | extern void __d_drop(struct dentry *dentry); |
224 | extern void d_drop(struct dentry *dentry); | |
1da177e4 | 225 | extern void d_delete(struct dentry *); |
fb045adb | 226 | extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
1da177e4 LT |
227 | |
228 | /* allocate/de-allocate */ | |
229 | extern struct dentry * d_alloc(struct dentry *, const struct qstr *); | |
f9c34674 | 230 | extern struct dentry * d_alloc_anon(struct super_block *); |
d9171b93 AV |
231 | extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, |
232 | wait_queue_head_t *); | |
1da177e4 | 233 | extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
e45b590b | 234 | extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
4f48d5da XL |
235 | extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent, |
236 | const struct qstr *name); | |
668d0cd5 | 237 | extern struct dentry * d_exact_alias(struct dentry *, struct inode *); |
46f72b34 | 238 | extern struct dentry *d_find_any_alias(struct inode *inode); |
4ea3ada2 | 239 | extern struct dentry * d_obtain_alias(struct inode *); |
1a0a397e | 240 | extern struct dentry * d_obtain_root(struct inode *); |
1da177e4 LT |
241 | extern void shrink_dcache_sb(struct super_block *); |
242 | extern void shrink_dcache_parent(struct dentry *); | |
c636ebdb | 243 | extern void shrink_dcache_for_umount(struct super_block *); |
5542aa2f | 244 | extern void d_invalidate(struct dentry *); |
1da177e4 LT |
245 | |
246 | /* only used at mount-time */ | |
adc0e91a | 247 | extern struct dentry * d_make_root(struct inode *); |
1da177e4 LT |
248 | |
249 | /* <clickety>-<click> the ramfs-type tree */ | |
250 | extern void d_genocide(struct dentry *); | |
251 | ||
771eb4fe | 252 | extern void d_mark_tmpfile(struct file *, struct inode *); |
863f144f | 253 | extern void d_tmpfile(struct file *, struct inode *); |
60545d0d | 254 | |
1da177e4 LT |
255 | extern struct dentry *d_find_alias(struct inode *); |
256 | extern void d_prune_aliases(struct inode *); | |
257 | ||
bca585d2 AV |
258 | extern struct dentry *d_find_alias_rcu(struct inode *); |
259 | ||
1da177e4 | 260 | /* test whether we have any submounts in a subdir tree */ |
01619491 | 261 | extern int path_has_submounts(const struct path *); |
1da177e4 LT |
262 | |
263 | /* | |
264 | * This adds the entry to the hash queues. | |
265 | */ | |
266 | extern void d_rehash(struct dentry *); | |
1da177e4 | 267 | |
34d0d19d | 268 | extern void d_add(struct dentry *, struct inode *); |
1da177e4 | 269 | |
1da177e4 LT |
270 | /* used for rename() and baskets */ |
271 | extern void d_move(struct dentry *, struct dentry *); | |
da1ce067 | 272 | extern void d_exchange(struct dentry *, struct dentry *); |
e2761a11 | 273 | extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
1da177e4 LT |
274 | |
275 | /* appendix may either be NULL or be used for transname suffixes */ | |
da2d8455 | 276 | extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
31e6b01f | 277 | extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
a713ca2a | 278 | extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
8966be90 | 279 | extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
da53be12 | 280 | const struct qstr *name, unsigned *seq); |
31e6b01f | 281 | |
24924a20 | 282 | static inline unsigned d_count(const struct dentry *dentry) |
84d08fa8 | 283 | { |
98474236 | 284 | return dentry->d_lockref.count; |
84d08fa8 AV |
285 | } |
286 | ||
c23fbb6b ED |
287 | /* |
288 | * helper function for dentry_operations.d_dname() members | |
289 | */ | |
0f60d288 AV |
290 | extern __printf(3, 4) |
291 | char *dynamic_dname(char *, int, const char *, ...); | |
c23fbb6b | 292 | |
02125a82 AV |
293 | extern char *__d_path(const struct path *, const struct path *, char *, int); |
294 | extern char *d_absolute_path(const struct path *, char *, int); | |
20d4fdc1 | 295 | extern char *d_path(const struct path *, char *, int); |
a2bbe664 AV |
296 | extern char *dentry_path_raw(const struct dentry *, char *, int); |
297 | extern char *dentry_path(const struct dentry *, char *, int); | |
cf28b486 | 298 | |
1da177e4 LT |
299 | /* Allocation counts.. */ |
300 | ||
301 | /** | |
dc0474be | 302 | * dget, dget_dlock - get a reference to a dentry |
1da177e4 LT |
303 | * @dentry: dentry to get a reference to |
304 | * | |
305 | * Given a dentry or %NULL pointer increment the reference count | |
306 | * if appropriate and return the dentry. A dentry will not be | |
dc0474be | 307 | * destroyed when it has references. |
1da177e4 | 308 | */ |
b7ab39f6 NP |
309 | static inline struct dentry *dget_dlock(struct dentry *dentry) |
310 | { | |
dc0474be | 311 | if (dentry) |
98474236 | 312 | dentry->d_lockref.count++; |
b7ab39f6 NP |
313 | return dentry; |
314 | } | |
2fd6b7f5 | 315 | |
1da177e4 LT |
316 | static inline struct dentry *dget(struct dentry *dentry) |
317 | { | |
98474236 WL |
318 | if (dentry) |
319 | lockref_get(&dentry->d_lockref); | |
1da177e4 LT |
320 | return dentry; |
321 | } | |
322 | ||
b7ab39f6 | 323 | extern struct dentry *dget_parent(struct dentry *dentry); |
1da177e4 LT |
324 | |
325 | /** | |
326 | * d_unhashed - is dentry hashed | |
327 | * @dentry: entry to check | |
328 | * | |
329 | * Returns true if the dentry passed is not currently hashed. | |
330 | */ | |
331 | ||
f0d3b3de | 332 | static inline int d_unhashed(const struct dentry *dentry) |
1da177e4 | 333 | { |
dea3667b | 334 | return hlist_bl_unhashed(&dentry->d_hash); |
1da177e4 LT |
335 | } |
336 | ||
f0d3b3de | 337 | static inline int d_unlinked(const struct dentry *dentry) |
f3da392e AD |
338 | { |
339 | return d_unhashed(dentry) && !IS_ROOT(dentry); | |
340 | } | |
341 | ||
f0d3b3de | 342 | static inline int cant_mount(const struct dentry *dentry) |
d83c49f3 AV |
343 | { |
344 | return (dentry->d_flags & DCACHE_CANT_MOUNT); | |
345 | } | |
346 | ||
347 | static inline void dont_mount(struct dentry *dentry) | |
348 | { | |
349 | spin_lock(&dentry->d_lock); | |
350 | dentry->d_flags |= DCACHE_CANT_MOUNT; | |
351 | spin_unlock(&dentry->d_lock); | |
352 | } | |
353 | ||
45f78b0a | 354 | extern void __d_lookup_unhash_wake(struct dentry *dentry); |
85c7f810 | 355 | |
4ded097b | 356 | static inline int d_in_lookup(const struct dentry *dentry) |
85c7f810 AV |
357 | { |
358 | return dentry->d_flags & DCACHE_PAR_LOOKUP; | |
359 | } | |
360 | ||
361 | static inline void d_lookup_done(struct dentry *dentry) | |
362 | { | |
45f78b0a SAS |
363 | if (unlikely(d_in_lookup(dentry))) |
364 | __d_lookup_unhash_wake(dentry); | |
85c7f810 AV |
365 | } |
366 | ||
1da177e4 LT |
367 | extern void dput(struct dentry *); |
368 | ||
f0d3b3de | 369 | static inline bool d_managed(const struct dentry *dentry) |
cc53ce53 DH |
370 | { |
371 | return dentry->d_flags & DCACHE_MANAGED_DENTRY; | |
372 | } | |
373 | ||
f0d3b3de | 374 | static inline bool d_mountpoint(const struct dentry *dentry) |
1da177e4 | 375 | { |
5f57cbcc | 376 | return dentry->d_flags & DCACHE_MOUNTED; |
1da177e4 LT |
377 | } |
378 | ||
b18825a7 DH |
379 | /* |
380 | * Directory cache entry type accessor functions. | |
381 | */ | |
b18825a7 DH |
382 | static inline unsigned __d_entry_type(const struct dentry *dentry) |
383 | { | |
a528aca7 | 384 | return dentry->d_flags & DCACHE_ENTRY_TYPE; |
b18825a7 DH |
385 | } |
386 | ||
e7f7d225 DH |
387 | static inline bool d_is_miss(const struct dentry *dentry) |
388 | { | |
389 | return __d_entry_type(dentry) == DCACHE_MISS_TYPE; | |
390 | } | |
391 | ||
392 | static inline bool d_is_whiteout(const struct dentry *dentry) | |
393 | { | |
394 | return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE; | |
395 | } | |
396 | ||
44b1d530 | 397 | static inline bool d_can_lookup(const struct dentry *dentry) |
b18825a7 DH |
398 | { |
399 | return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE; | |
400 | } | |
401 | ||
402 | static inline bool d_is_autodir(const struct dentry *dentry) | |
403 | { | |
404 | return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE; | |
405 | } | |
406 | ||
44b1d530 MS |
407 | static inline bool d_is_dir(const struct dentry *dentry) |
408 | { | |
409 | return d_can_lookup(dentry) || d_is_autodir(dentry); | |
410 | } | |
411 | ||
b18825a7 DH |
412 | static inline bool d_is_symlink(const struct dentry *dentry) |
413 | { | |
414 | return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE; | |
415 | } | |
416 | ||
44bdb5e5 DH |
417 | static inline bool d_is_reg(const struct dentry *dentry) |
418 | { | |
419 | return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE; | |
420 | } | |
421 | ||
422 | static inline bool d_is_special(const struct dentry *dentry) | |
423 | { | |
424 | return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE; | |
425 | } | |
426 | ||
b18825a7 DH |
427 | static inline bool d_is_file(const struct dentry *dentry) |
428 | { | |
44bdb5e5 | 429 | return d_is_reg(dentry) || d_is_special(dentry); |
b18825a7 DH |
430 | } |
431 | ||
432 | static inline bool d_is_negative(const struct dentry *dentry) | |
433 | { | |
e7f7d225 DH |
434 | // TODO: check d_is_whiteout(dentry) also. |
435 | return d_is_miss(dentry); | |
b18825a7 DH |
436 | } |
437 | ||
d41efb52 AV |
438 | static inline bool d_flags_negative(unsigned flags) |
439 | { | |
440 | return (flags & DCACHE_ENTRY_TYPE) == DCACHE_MISS_TYPE; | |
441 | } | |
442 | ||
b18825a7 DH |
443 | static inline bool d_is_positive(const struct dentry *dentry) |
444 | { | |
445 | return !d_is_negative(dentry); | |
446 | } | |
447 | ||
525d27b2 DH |
448 | /** |
449 | * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs) | |
450 | * @dentry: The dentry in question | |
451 | * | |
452 | * Returns true if the dentry represents either an absent name or a name that | |
453 | * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent | |
454 | * a true miss, a whiteout that isn't represented by a 0,0 chardev or a | |
455 | * fallthrough marker in an opaque directory. | |
456 | * | |
457 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
458 | * dentries. It should not be used to look at some other filesystem's | |
459 | * dentries. (2) It should also be used in combination with d_inode() to get | |
460 | * the inode. (3) The dentry may have something attached to ->d_lower and the | |
461 | * type field of the flags may be set to something other than miss or whiteout. | |
462 | */ | |
463 | static inline bool d_really_is_negative(const struct dentry *dentry) | |
464 | { | |
465 | return dentry->d_inode == NULL; | |
466 | } | |
467 | ||
468 | /** | |
469 | * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs) | |
470 | * @dentry: The dentry in question | |
471 | * | |
472 | * Returns true if the dentry represents a name that maps to an inode | |
473 | * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if | |
474 | * that is represented on medium as a 0,0 chardev. | |
475 | * | |
476 | * Note! (1) This should be used *only* by a filesystem to examine its own | |
477 | * dentries. It should not be used to look at some other filesystem's | |
478 | * dentries. (2) It should also be used in combination with d_inode() to get | |
479 | * the inode. | |
480 | */ | |
481 | static inline bool d_really_is_positive(const struct dentry *dentry) | |
482 | { | |
483 | return dentry->d_inode != NULL; | |
484 | } | |
485 | ||
4ded097b | 486 | static inline int simple_positive(const struct dentry *dentry) |
dc3f4198 AV |
487 | { |
488 | return d_really_is_positive(dentry) && !d_unhashed(dentry); | |
489 | } | |
490 | ||
1da177e4 LT |
491 | extern int sysctl_vfs_cache_pressure; |
492 | ||
55f841ce GC |
493 | static inline unsigned long vfs_pressure_ratio(unsigned long val) |
494 | { | |
495 | return mult_frac(val, sysctl_vfs_cache_pressure, 100); | |
496 | } | |
155e35d4 DH |
497 | |
498 | /** | |
499 | * d_inode - Get the actual inode of this dentry | |
500 | * @dentry: The dentry to query | |
501 | * | |
502 | * This is the helper normal filesystems should use to get at their own inodes | |
503 | * in their own dentries and ignore the layering superimposed upon them. | |
504 | */ | |
505 | static inline struct inode *d_inode(const struct dentry *dentry) | |
506 | { | |
507 | return dentry->d_inode; | |
508 | } | |
509 | ||
510 | /** | |
66702eb5 | 511 | * d_inode_rcu - Get the actual inode of this dentry with READ_ONCE() |
155e35d4 DH |
512 | * @dentry: The dentry to query |
513 | * | |
514 | * This is the helper normal filesystems should use to get at their own inodes | |
515 | * in their own dentries and ignore the layering superimposed upon them. | |
516 | */ | |
517 | static inline struct inode *d_inode_rcu(const struct dentry *dentry) | |
518 | { | |
66702eb5 | 519 | return READ_ONCE(dentry->d_inode); |
155e35d4 DH |
520 | } |
521 | ||
522 | /** | |
523 | * d_backing_inode - Get upper or lower inode we should be using | |
524 | * @upper: The upper layer | |
525 | * | |
526 | * This is the helper that should be used to get at the inode that will be used | |
527 | * if this dentry were to be opened as a file. The inode may be on the upper | |
528 | * dentry or it may be on a lower dentry pinned by the upper. | |
529 | * | |
530 | * Normal filesystems should not use this to access their own inodes. | |
531 | */ | |
532 | static inline struct inode *d_backing_inode(const struct dentry *upper) | |
533 | { | |
534 | struct inode *inode = upper->d_inode; | |
535 | ||
536 | return inode; | |
537 | } | |
538 | ||
539 | /** | |
540 | * d_backing_dentry - Get upper or lower dentry we should be using | |
541 | * @upper: The upper layer | |
542 | * | |
543 | * This is the helper that should be used to get the dentry of the inode that | |
544 | * will be used if this dentry were opened as a file. It may be the upper | |
545 | * dentry or it may be a lower dentry pinned by the upper. | |
546 | * | |
547 | * Normal filesystems should not use this to access their own dentries. | |
548 | */ | |
549 | static inline struct dentry *d_backing_dentry(struct dentry *upper) | |
550 | { | |
551 | return upper; | |
552 | } | |
553 | ||
e698b8a4 MS |
554 | /** |
555 | * d_real - Return the real dentry | |
556 | * @dentry: the dentry to query | |
557 | * @inode: inode to select the dentry from multiple layers (can be NULL) | |
e698b8a4 | 558 | * |
03440c4e | 559 | * If dentry is on a union/overlay, then return the underlying, real dentry. |
e698b8a4 MS |
560 | * Otherwise return the dentry itself. |
561 | * | |
5c437fa2 | 562 | * See also: Documentation/filesystems/vfs.rst |
e698b8a4 | 563 | */ |
2d902671 | 564 | static inline struct dentry *d_real(struct dentry *dentry, |
fb16043b | 565 | const struct inode *inode) |
d101a125 MS |
566 | { |
567 | if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) | |
fb16043b | 568 | return dentry->d_op->d_real(dentry, inode); |
d101a125 MS |
569 | else |
570 | return dentry; | |
571 | } | |
572 | ||
a1180844 MS |
573 | /** |
574 | * d_real_inode - Return the real inode | |
575 | * @dentry: The dentry to query | |
576 | * | |
03440c4e | 577 | * If dentry is on a union/overlay, then return the underlying, real inode. |
a1180844 MS |
578 | * Otherwise return d_inode(). |
579 | */ | |
7b1742eb | 580 | static inline struct inode *d_real_inode(const struct dentry *dentry) |
a1180844 | 581 | { |
7b1742eb | 582 | /* This usage of d_real() results in const dentry */ |
fb16043b | 583 | return d_backing_inode(d_real((struct dentry *) dentry, NULL)); |
a1180844 MS |
584 | } |
585 | ||
49d31c2f | 586 | struct name_snapshot { |
230c6402 | 587 | struct qstr name; |
0a2c13d9 | 588 | unsigned char inline_name[DNAME_INLINE_LEN]; |
49d31c2f AV |
589 | }; |
590 | void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); | |
591 | void release_dentry_name_snapshot(struct name_snapshot *); | |
54d5ca87 | 592 | |
1da177e4 | 593 | #endif /* __LINUX_DCACHE_H */ |