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1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * fs/dcache.c
4 : : *
5 : : * Complete reimplementation
6 : : * (C) 1997 Thomas Schoebel-Theuer,
7 : : * with heavy changes by Linus Torvalds
8 : : */
9 : :
10 : : /*
11 : : * Notes on the allocation strategy:
12 : : *
13 : : * The dcache is a master of the icache - whenever a dcache entry
14 : : * exists, the inode will always exist. "iput()" is done either when
15 : : * the dcache entry is deleted or garbage collected.
16 : : */
17 : :
18 : : #include <linux/ratelimit.h>
19 : : #include <linux/string.h>
20 : : #include <linux/mm.h>
21 : : #include <linux/fs.h>
22 : : #include <linux/fscrypt.h>
23 : : #include <linux/fsnotify.h>
24 : : #include <linux/slab.h>
25 : : #include <linux/init.h>
26 : : #include <linux/hash.h>
27 : : #include <linux/cache.h>
28 : : #include <linux/export.h>
29 : : #include <linux/security.h>
30 : : #include <linux/seqlock.h>
31 : : #include <linux/memblock.h>
32 : : #include <linux/bit_spinlock.h>
33 : : #include <linux/rculist_bl.h>
34 : : #include <linux/list_lru.h>
35 : : #include "internal.h"
36 : : #include "mount.h"
37 : :
38 : : /*
39 : : * Usage:
40 : : * dcache->d_inode->i_lock protects:
41 : : * - i_dentry, d_u.d_alias, d_inode of aliases
42 : : * dcache_hash_bucket lock protects:
43 : : * - the dcache hash table
44 : : * s_roots bl list spinlock protects:
45 : : * - the s_roots list (see __d_drop)
46 : : * dentry->d_sb->s_dentry_lru_lock protects:
47 : : * - the dcache lru lists and counters
48 : : * d_lock protects:
49 : : * - d_flags
50 : : * - d_name
51 : : * - d_lru
52 : : * - d_count
53 : : * - d_unhashed()
54 : : * - d_parent and d_subdirs
55 : : * - childrens' d_child and d_parent
56 : : * - d_u.d_alias, d_inode
57 : : *
58 : : * Ordering:
59 : : * dentry->d_inode->i_lock
60 : : * dentry->d_lock
61 : : * dentry->d_sb->s_dentry_lru_lock
62 : : * dcache_hash_bucket lock
63 : : * s_roots lock
64 : : *
65 : : * If there is an ancestor relationship:
66 : : * dentry->d_parent->...->d_parent->d_lock
67 : : * ...
68 : : * dentry->d_parent->d_lock
69 : : * dentry->d_lock
70 : : *
71 : : * If no ancestor relationship:
72 : : * arbitrary, since it's serialized on rename_lock
73 : : */
74 : : int sysctl_vfs_cache_pressure __read_mostly = 100;
75 : : EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
76 : :
77 : : __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
78 : :
79 : : EXPORT_SYMBOL(rename_lock);
80 : :
81 : : static struct kmem_cache *dentry_cache __read_mostly;
82 : :
83 : : const struct qstr empty_name = QSTR_INIT("", 0);
84 : : EXPORT_SYMBOL(empty_name);
85 : : const struct qstr slash_name = QSTR_INIT("/", 1);
86 : : EXPORT_SYMBOL(slash_name);
87 : :
88 : : /*
89 : : * This is the single most critical data structure when it comes
90 : : * to the dcache: the hashtable for lookups. Somebody should try
91 : : * to make this good - I've just made it work.
92 : : *
93 : : * This hash-function tries to avoid losing too many bits of hash
94 : : * information, yet avoid using a prime hash-size or similar.
95 : : */
96 : :
97 : : static unsigned int d_hash_shift __read_mostly;
98 : :
99 : : static struct hlist_bl_head *dentry_hashtable __read_mostly;
100 : :
101 : 22332959 : static inline struct hlist_bl_head *d_hash(unsigned int hash)
102 : : {
103 : 22332959 : return dentry_hashtable + (hash >> d_hash_shift);
104 : : }
105 : :
106 : : #define IN_LOOKUP_SHIFT 10
107 : : static struct hlist_bl_head in_lookup_hashtable[1 << IN_LOOKUP_SHIFT];
108 : :
109 : 4407148 : static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent,
110 : : unsigned int hash)
111 : : {
112 : 4407148 : hash += (unsigned long) parent / L1_CACHE_BYTES;
113 : 4407148 : return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT);
114 : : }
115 : :
116 : :
117 : : /* Statistics gathering. */
118 : : struct dentry_stat_t dentry_stat = {
119 : : .age_limit = 45,
120 : : };
121 : :
122 : : static DEFINE_PER_CPU(long, nr_dentry);
123 : : static DEFINE_PER_CPU(long, nr_dentry_unused);
124 : : static DEFINE_PER_CPU(long, nr_dentry_negative);
125 : :
126 : : #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
127 : :
128 : : /*
129 : : * Here we resort to our own counters instead of using generic per-cpu counters
130 : : * for consistency with what the vfs inode code does. We are expected to harvest
131 : : * better code and performance by having our own specialized counters.
132 : : *
133 : : * Please note that the loop is done over all possible CPUs, not over all online
134 : : * CPUs. The reason for this is that we don't want to play games with CPUs going
135 : : * on and off. If one of them goes off, we will just keep their counters.
136 : : *
137 : : * glommer: See cffbc8a for details, and if you ever intend to change this,
138 : : * please update all vfs counters to match.
139 : : */
140 : 0 : static long get_nr_dentry(void)
141 : : {
142 : 0 : int i;
143 : 0 : long sum = 0;
144 [ # # ]: 0 : for_each_possible_cpu(i)
145 : 0 : sum += per_cpu(nr_dentry, i);
146 : 0 : return sum < 0 ? 0 : sum;
147 : : }
148 : :
149 : 0 : static long get_nr_dentry_unused(void)
150 : : {
151 : 0 : int i;
152 : 0 : long sum = 0;
153 [ # # ]: 0 : for_each_possible_cpu(i)
154 : 0 : sum += per_cpu(nr_dentry_unused, i);
155 : 0 : return sum < 0 ? 0 : sum;
156 : : }
157 : :
158 : 0 : static long get_nr_dentry_negative(void)
159 : : {
160 : 0 : int i;
161 : 0 : long sum = 0;
162 : :
163 [ # # ]: 0 : for_each_possible_cpu(i)
164 : 0 : sum += per_cpu(nr_dentry_negative, i);
165 : 0 : return sum < 0 ? 0 : sum;
166 : : }
167 : :
168 : 0 : int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer,
169 : : size_t *lenp, loff_t *ppos)
170 : : {
171 : 0 : dentry_stat.nr_dentry = get_nr_dentry();
172 : 0 : dentry_stat.nr_unused = get_nr_dentry_unused();
173 : 0 : dentry_stat.nr_negative = get_nr_dentry_negative();
174 : 0 : return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
175 : : }
176 : : #endif
177 : :
178 : : /*
179 : : * Compare 2 name strings, return 0 if they match, otherwise non-zero.
180 : : * The strings are both count bytes long, and count is non-zero.
181 : : */
182 : : #ifdef CONFIG_DCACHE_WORD_ACCESS
183 : :
184 : : #include <asm/word-at-a-time.h>
185 : : /*
186 : : * NOTE! 'cs' and 'scount' come from a dentry, so it has a
187 : : * aligned allocation for this particular component. We don't
188 : : * strictly need the load_unaligned_zeropad() safety, but it
189 : : * doesn't hurt either.
190 : : *
191 : : * In contrast, 'ct' and 'tcount' can be from a pathname, and do
192 : : * need the careful unaligned handling.
193 : : */
194 : 14765305 : static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
195 : : {
196 : 18007865 : unsigned long a,b,mask;
197 : :
198 : 18007865 : for (;;) {
199 : 18007865 : a = read_word_at_a_time(cs);
200 : 18007865 : b = load_unaligned_zeropad(ct);
201 [ + + ]: 18007865 : if (tcount < sizeof(unsigned long))
202 : : break;
203 [ + - ]: 3811305 : if (unlikely(a != b))
204 : : return 1;
205 : 3811305 : cs += sizeof(unsigned long);
206 : 3811305 : ct += sizeof(unsigned long);
207 : 3811305 : tcount -= sizeof(unsigned long);
208 [ + + ]: 3811305 : if (!tcount)
209 : : return 0;
210 : : }
211 : 14196560 : mask = bytemask_from_count(tcount);
212 : 14196560 : return unlikely(!!((a ^ b) & mask));
213 : : }
214 : :
215 : : #else
216 : :
217 : : static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
218 : : {
219 : : do {
220 : : if (*cs != *ct)
221 : : return 1;
222 : : cs++;
223 : : ct++;
224 : : tcount--;
225 : : } while (tcount);
226 : : return 0;
227 : : }
228 : :
229 : : #endif
230 : :
231 : 11418402 : static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount)
232 : : {
233 : : /*
234 : : * Be careful about RCU walk racing with rename:
235 : : * use 'READ_ONCE' to fetch the name pointer.
236 : : *
237 : : * NOTE! Even if a rename will mean that the length
238 : : * was not loaded atomically, we don't care. The
239 : : * RCU walk will check the sequence count eventually,
240 : : * and catch it. And we won't overrun the buffer,
241 : : * because we're reading the name pointer atomically,
242 : : * and a dentry name is guaranteed to be properly
243 : : * terminated with a NUL byte.
244 : : *
245 : : * End result: even if 'len' is wrong, we'll exit
246 : : * early because the data cannot match (there can
247 : : * be no NUL in the ct/tcount data)
248 : : */
249 : 11418402 : const unsigned char *cs = READ_ONCE(dentry->d_name.name);
250 : :
251 : 11418402 : return dentry_string_cmp(cs, ct, tcount);
252 : : }
253 : :
254 : : struct external_name {
255 : : union {
256 : : atomic_t count;
257 : : struct rcu_head head;
258 : : } u;
259 : : unsigned char name[];
260 : : };
261 : :
262 : 80646 : static inline struct external_name *external_name(struct dentry *dentry)
263 : : {
264 : 80646 : return container_of(dentry->d_name.name, struct external_name, name[0]);
265 : : }
266 : :
267 : 857094 : static void __d_free(struct rcu_head *head)
268 : : {
269 : 857094 : struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
270 : :
271 : 830604 : kmem_cache_free(dentry_cache, dentry);
272 : 26490 : }
273 : :
274 : 36944 : static void __d_free_external(struct rcu_head *head)
275 : : {
276 : 36944 : struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
277 : 36944 : kfree(external_name(dentry));
278 : 36944 : kmem_cache_free(dentry_cache, dentry);
279 : 36944 : }
280 : :
281 : 948914 : static inline int dname_external(const struct dentry *dentry)
282 : : {
283 : 948914 : return dentry->d_name.name != dentry->d_iname;
284 : : }
285 : :
286 : 18396 : void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
287 : : {
288 : 18396 : spin_lock(&dentry->d_lock);
289 : 18396 : name->name = dentry->d_name;
290 [ + + ]: 18396 : if (unlikely(dname_external(dentry))) {
291 : 2053 : atomic_inc(&external_name(dentry)->u.count);
292 : : } else {
293 : 16343 : memcpy(name->inline_name, dentry->d_iname,
294 : 16343 : dentry->d_name.len + 1);
295 : 16343 : name->name.name = name->inline_name;
296 : : }
297 : 18396 : spin_unlock(&dentry->d_lock);
298 : 18396 : }
299 : : EXPORT_SYMBOL(take_dentry_name_snapshot);
300 : :
301 : 18396 : void release_dentry_name_snapshot(struct name_snapshot *name)
302 : : {
303 [ + + ]: 18396 : if (unlikely(name->name.name != name->inline_name)) {
304 : 2053 : struct external_name *p;
305 : 2053 : p = container_of(name->name.name, struct external_name, name[0]);
306 [ + - ]: 2053 : if (unlikely(atomic_dec_and_test(&p->u.count)))
307 [ + - ]: 2053 : kfree_rcu(p, u.head);
308 : : }
309 : 18396 : }
310 : : EXPORT_SYMBOL(release_dentry_name_snapshot);
311 : :
312 : 1583668 : static inline void __d_set_inode_and_type(struct dentry *dentry,
313 : : struct inode *inode,
314 : : unsigned type_flags)
315 : : {
316 : 1583668 : unsigned flags;
317 : :
318 : 1583668 : dentry->d_inode = inode;
319 : 1583668 : flags = READ_ONCE(dentry->d_flags);
320 : 1583668 : flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
321 : 1583668 : flags |= type_flags;
322 [ - - ]: 1583668 : smp_store_release(&dentry->d_flags, flags);
323 : : }
324 : :
325 : 166486 : static inline void __d_clear_type_and_inode(struct dentry *dentry)
326 : : {
327 : 166486 : unsigned flags = READ_ONCE(dentry->d_flags);
328 : :
329 : 166486 : flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
330 [ + + ]: 166486 : WRITE_ONCE(dentry->d_flags, flags);
331 : 166486 : dentry->d_inode = NULL;
332 [ + + ]: 166486 : if (dentry->d_flags & DCACHE_LRU_LIST)
333 : 166486 : this_cpu_inc(nr_dentry_negative);
334 : : }
335 : :
336 : 894038 : static void dentry_free(struct dentry *dentry)
337 : : {
338 [ - + ]: 894038 : WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
339 [ + + ]: 894038 : if (unlikely(dname_external(dentry))) {
340 : 38270 : struct external_name *p = external_name(dentry);
341 [ + + ]: 38270 : if (likely(atomic_dec_and_test(&p->u.count))) {
342 : 36944 : call_rcu(&dentry->d_u.d_rcu, __d_free_external);
343 : 36944 : return;
344 : : }
345 : : }
346 : : /* if dentry was never visible to RCU, immediate free is OK */
347 [ + + ]: 857094 : if (dentry->d_flags & DCACHE_NORCU)
348 : 26490 : __d_free(&dentry->d_u.d_rcu);
349 : : else
350 : 830604 : call_rcu(&dentry->d_u.d_rcu, __d_free);
351 : : }
352 : :
353 : : /*
354 : : * Release the dentry's inode, using the filesystem
355 : : * d_iput() operation if defined.
356 : : */
357 : 166486 : static void dentry_unlink_inode(struct dentry * dentry)
358 : : __releases(dentry->d_lock)
359 : : __releases(dentry->d_inode->i_lock)
360 : : {
361 : 166486 : struct inode *inode = dentry->d_inode;
362 : :
363 : 166486 : raw_write_seqcount_begin(&dentry->d_seq);
364 [ + + ]: 166486 : __d_clear_type_and_inode(dentry);
365 [ + - ]: 166486 : hlist_del_init(&dentry->d_u.d_alias);
366 : 166486 : raw_write_seqcount_end(&dentry->d_seq);
367 : 166486 : spin_unlock(&dentry->d_lock);
368 : 166486 : spin_unlock(&inode->i_lock);
369 [ + + ]: 166486 : if (!inode->i_nlink)
370 : 9287 : fsnotify_inoderemove(inode);
371 [ + + - + ]: 166486 : if (dentry->d_op && dentry->d_op->d_iput)
372 : 0 : dentry->d_op->d_iput(dentry, inode);
373 : : else
374 : 166486 : iput(inode);
375 : 166486 : }
376 : :
377 : : /*
378 : : * The DCACHE_LRU_LIST bit is set whenever the 'd_lru' entry
379 : : * is in use - which includes both the "real" per-superblock
380 : : * LRU list _and_ the DCACHE_SHRINK_LIST use.
381 : : *
382 : : * The DCACHE_SHRINK_LIST bit is set whenever the dentry is
383 : : * on the shrink list (ie not on the superblock LRU list).
384 : : *
385 : : * The per-cpu "nr_dentry_unused" counters are updated with
386 : : * the DCACHE_LRU_LIST bit.
387 : : *
388 : : * The per-cpu "nr_dentry_negative" counters are only updated
389 : : * when deleted from or added to the per-superblock LRU list, not
390 : : * from/to the shrink list. That is to avoid an unneeded dec/inc
391 : : * pair when moving from LRU to shrink list in select_collect().
392 : : *
393 : : * These helper functions make sure we always follow the
394 : : * rules. d_lock must be held by the caller.
395 : : */
396 : : #define D_FLAG_VERIFY(dentry,x) WARN_ON_ONCE(((dentry)->d_flags & (DCACHE_LRU_LIST | DCACHE_SHRINK_LIST)) != (x))
397 : 449218 : static void d_lru_add(struct dentry *dentry)
398 : : {
399 [ - + ]: 449218 : D_FLAG_VERIFY(dentry, 0);
400 : 449218 : dentry->d_flags |= DCACHE_LRU_LIST;
401 : 449218 : this_cpu_inc(nr_dentry_unused);
402 [ + + ]: 449218 : if (d_is_negative(dentry))
403 : 449218 : this_cpu_inc(nr_dentry_negative);
404 [ - + ]: 449218 : WARN_ON_ONCE(!list_lru_add(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
405 : 449218 : }
406 : :
407 : 100906 : static void d_lru_del(struct dentry *dentry)
408 : : {
409 [ - + ]: 100906 : D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
410 : 100906 : dentry->d_flags &= ~DCACHE_LRU_LIST;
411 : 100906 : this_cpu_dec(nr_dentry_unused);
412 [ + + ]: 100906 : if (d_is_negative(dentry))
413 : 100906 : this_cpu_dec(nr_dentry_negative);
414 [ - + ]: 100906 : WARN_ON_ONCE(!list_lru_del(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
415 : 100906 : }
416 : :
417 : 132981 : static void d_shrink_del(struct dentry *dentry)
418 : : {
419 [ - + ]: 132981 : D_FLAG_VERIFY(dentry, DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
420 : 132981 : list_del_init(&dentry->d_lru);
421 : 132981 : dentry->d_flags &= ~(DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
422 : 132981 : this_cpu_dec(nr_dentry_unused);
423 : 132981 : }
424 : :
425 : 105590 : static void d_shrink_add(struct dentry *dentry, struct list_head *list)
426 : : {
427 : 0 : D_FLAG_VERIFY(dentry, 0);
428 : 105590 : list_add(&dentry->d_lru, list);
429 : 105590 : dentry->d_flags |= DCACHE_SHRINK_LIST | DCACHE_LRU_LIST;
430 : 105590 : this_cpu_inc(nr_dentry_unused);
431 : 5074 : }
432 : :
433 : : /*
434 : : * These can only be called under the global LRU lock, ie during the
435 : : * callback for freeing the LRU list. "isolate" removes it from the
436 : : * LRU lists entirely, while shrink_move moves it to the indicated
437 : : * private list.
438 : : */
439 : 0 : static void d_lru_isolate(struct list_lru_one *lru, struct dentry *dentry)
440 : : {
441 [ # # ]: 0 : D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
442 : 0 : dentry->d_flags &= ~DCACHE_LRU_LIST;
443 : 0 : this_cpu_dec(nr_dentry_unused);
444 [ # # ]: 0 : if (d_is_negative(dentry))
445 : 0 : this_cpu_dec(nr_dentry_negative);
446 : 0 : list_lru_isolate(lru, &dentry->d_lru);
447 : 0 : }
448 : :
449 : 27391 : static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry,
450 : : struct list_head *list)
451 : : {
452 [ - + ]: 27391 : D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
453 : 27391 : dentry->d_flags |= DCACHE_SHRINK_LIST;
454 [ + + ]: 27391 : if (d_is_negative(dentry))
455 : 27391 : this_cpu_dec(nr_dentry_negative);
456 : 27391 : list_lru_isolate_move(lru, &dentry->d_lru, list);
457 : 27391 : }
458 : :
459 : : /**
460 : : * d_drop - drop a dentry
461 : : * @dentry: dentry to drop
462 : : *
463 : : * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
464 : : * be found through a VFS lookup any more. Note that this is different from
465 : : * deleting the dentry - d_delete will try to mark the dentry negative if
466 : : * possible, giving a successful _negative_ lookup, while d_drop will
467 : : * just make the cache lookup fail.
468 : : *
469 : : * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
470 : : * reason (NFS timeouts or autofs deletes).
471 : : *
472 : : * __d_drop requires dentry->d_lock
473 : : * ___d_drop doesn't mark dentry as "unhashed"
474 : : * (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
475 : : */
476 : 621760 : static void ___d_drop(struct dentry *dentry)
477 : : {
478 : 621760 : struct hlist_bl_head *b;
479 : : /*
480 : : * Hashed dentries are normally on the dentry hashtable,
481 : : * with the exception of those newly allocated by
482 : : * d_obtain_root, which are always IS_ROOT:
483 : : */
484 [ - + ]: 621760 : if (unlikely(IS_ROOT(dentry)))
485 : 0 : b = &dentry->d_sb->s_roots;
486 : : else
487 : 621760 : b = d_hash(dentry->d_name.hash);
488 : :
489 : 621760 : hlist_bl_lock(b);
490 [ + + ]: 621760 : __hlist_bl_del(&dentry->d_hash);
491 : 621760 : hlist_bl_unlock(b);
492 : 621760 : }
493 : :
494 : 897697 : void __d_drop(struct dentry *dentry)
495 : : {
496 [ # # ]: 0 : if (!d_unhashed(dentry)) {
497 : 585280 : ___d_drop(dentry);
498 : 585280 : dentry->d_hash.pprev = NULL;
499 : 585280 : write_seqcount_invalidate(&dentry->d_seq);
500 : : }
501 : 0 : }
502 : : EXPORT_SYMBOL(__d_drop);
503 : :
504 : 0 : void d_drop(struct dentry *dentry)
505 : : {
506 : 0 : spin_lock(&dentry->d_lock);
507 [ # # ]: 0 : __d_drop(dentry);
508 : 0 : spin_unlock(&dentry->d_lock);
509 : 0 : }
510 : : EXPORT_SYMBOL(d_drop);
511 : :
512 : 894038 : static inline void dentry_unlist(struct dentry *dentry, struct dentry *parent)
513 : : {
514 : 894038 : struct dentry *next;
515 : : /*
516 : : * Inform d_walk() and shrink_dentry_list() that we are no longer
517 : : * attached to the dentry tree
518 : : */
519 : 894038 : dentry->d_flags |= DCACHE_DENTRY_KILLED;
520 : 894038 : if (unlikely(list_empty(&dentry->d_child)))
521 : : return;
522 : 844304 : __list_del_entry(&dentry->d_child);
523 : : /*
524 : : * Cursors can move around the list of children. While we'd been
525 : : * a normal list member, it didn't matter - ->d_child.next would've
526 : : * been updated. However, from now on it won't be and for the
527 : : * things like d_walk() it might end up with a nasty surprise.
528 : : * Normally d_walk() doesn't care about cursors moving around -
529 : : * ->d_lock on parent prevents that and since a cursor has no children
530 : : * of its own, we get through it without ever unlocking the parent.
531 : : * There is one exception, though - if we ascend from a child that
532 : : * gets killed as soon as we unlock it, the next sibling is found
533 : : * using the value left in its ->d_child.next. And if _that_
534 : : * pointed to a cursor, and cursor got moved (e.g. by lseek())
535 : : * before d_walk() regains parent->d_lock, we'll end up skipping
536 : : * everything the cursor had been moved past.
537 : : *
538 : : * Solution: make sure that the pointer left behind in ->d_child.next
539 : : * points to something that won't be moving around. I.e. skip the
540 : : * cursors.
541 : : */
542 [ + + ]: 844304 : while (dentry->d_child.next != &parent->d_subdirs) {
543 : 751478 : next = list_entry(dentry->d_child.next, struct dentry, d_child);
544 [ - + ]: 751478 : if (likely(!(next->d_flags & DCACHE_DENTRY_CURSOR)))
545 : : break;
546 : 0 : dentry->d_child.next = next->d_child.next;
547 : : }
548 : : }
549 : :
550 : 894038 : static void __dentry_kill(struct dentry *dentry)
551 : : {
552 : 894038 : struct dentry *parent = NULL;
553 : 894038 : bool can_free = true;
554 [ + + ]: 894038 : if (!IS_ROOT(dentry))
555 : 867548 : parent = dentry->d_parent;
556 : :
557 : : /*
558 : : * The dentry is now unrecoverably dead to the world.
559 : : */
560 : 894038 : lockref_mark_dead(&dentry->d_lockref);
561 : :
562 : : /*
563 : : * inform the fs via d_prune that this dentry is about to be
564 : : * unhashed and destroyed.
565 : : */
566 [ - + ]: 894038 : if (dentry->d_flags & DCACHE_OP_PRUNE)
567 : 0 : dentry->d_op->d_prune(dentry);
568 : :
569 [ + + ]: 894038 : if (dentry->d_flags & DCACHE_LRU_LIST) {
570 [ + - ]: 312 : if (!(dentry->d_flags & DCACHE_SHRINK_LIST))
571 : 312 : d_lru_del(dentry);
572 : : }
573 : : /* if it was on the hash then remove it */
574 [ + + ]: 894038 : __d_drop(dentry);
575 [ + + ]: 894038 : dentry_unlist(dentry, parent);
576 [ + + ]: 894038 : if (parent)
577 : 867548 : spin_unlock(&parent->d_lock);
578 [ + + ]: 894038 : if (dentry->d_inode)
579 : 156686 : dentry_unlink_inode(dentry);
580 : : else
581 : 737352 : spin_unlock(&dentry->d_lock);
582 : 894038 : this_cpu_dec(nr_dentry);
583 [ + + + + ]: 894038 : if (dentry->d_op && dentry->d_op->d_release)
584 : 21138 : dentry->d_op->d_release(dentry);
585 : :
586 : 894038 : spin_lock(&dentry->d_lock);
587 [ - + ]: 894038 : if (dentry->d_flags & DCACHE_SHRINK_LIST) {
588 : 0 : dentry->d_flags |= DCACHE_MAY_FREE;
589 : 0 : can_free = false;
590 : : }
591 : 894038 : spin_unlock(&dentry->d_lock);
592 [ + - ]: 894038 : if (likely(can_free))
593 : 894038 : dentry_free(dentry);
594 : 894038 : cond_resched();
595 : 894038 : }
596 : :
597 : 0 : static struct dentry *__lock_parent(struct dentry *dentry)
598 : : {
599 : 0 : struct dentry *parent;
600 : 0 : rcu_read_lock();
601 : 0 : spin_unlock(&dentry->d_lock);
602 : 0 : again:
603 : 0 : parent = READ_ONCE(dentry->d_parent);
604 : 0 : spin_lock(&parent->d_lock);
605 : : /*
606 : : * We can't blindly lock dentry until we are sure
607 : : * that we won't violate the locking order.
608 : : * Any changes of dentry->d_parent must have
609 : : * been done with parent->d_lock held, so
610 : : * spin_lock() above is enough of a barrier
611 : : * for checking if it's still our child.
612 : : */
613 [ # # ]: 0 : if (unlikely(parent != dentry->d_parent)) {
614 : 0 : spin_unlock(&parent->d_lock);
615 : 0 : goto again;
616 : : }
617 : 0 : rcu_read_unlock();
618 [ # # ]: 0 : if (parent != dentry)
619 : 0 : spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
620 : : else
621 : : parent = NULL;
622 : 0 : return parent;
623 : : }
624 : :
625 : 0 : static inline struct dentry *lock_parent(struct dentry *dentry)
626 : : {
627 : 0 : struct dentry *parent = dentry->d_parent;
628 [ # # ]: 0 : if (IS_ROOT(dentry))
629 : : return NULL;
630 [ # # ]: 0 : if (likely(spin_trylock(&parent->d_lock)))
631 : : return parent;
632 : 0 : return __lock_parent(dentry);
633 : : }
634 : :
635 : 1379132 : static inline bool retain_dentry(struct dentry *dentry)
636 : : {
637 [ - + ]: 1379132 : WARN_ON(d_in_lookup(dentry));
638 : :
639 : : /* Unreachable? Get rid of it */
640 [ + + ]: 1379132 : if (unlikely(d_unhashed(dentry)))
641 : : return false;
642 : :
643 [ + - ]: 1066715 : if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
644 : : return false;
645 : :
646 [ + + ]: 1066715 : if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) {
647 [ + + ]: 628294 : if (dentry->d_op->d_delete(dentry))
648 : : return false;
649 : : }
650 : : /* retain; LRU fodder */
651 : 615302 : dentry->d_lockref.count--;
652 [ + + ]: 615302 : if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
653 : 449218 : d_lru_add(dentry);
654 [ + + ]: 166084 : else if (unlikely(!(dentry->d_flags & DCACHE_REFERENCED)))
655 : 130419 : dentry->d_flags |= DCACHE_REFERENCED;
656 : : return true;
657 : : }
658 : :
659 : : /*
660 : : * Finish off a dentry we've decided to kill.
661 : : * dentry->d_lock must be held, returns with it unlocked.
662 : : * Returns dentry requiring refcount drop, or NULL if we're done.
663 : : */
664 : 763830 : static struct dentry *dentry_kill(struct dentry *dentry)
665 : : __releases(dentry->d_lock)
666 : : {
667 : 763830 : struct inode *inode = dentry->d_inode;
668 : 763830 : struct dentry *parent = NULL;
669 : :
670 [ + + - + ]: 796385 : if (inode && unlikely(!spin_trylock(&inode->i_lock)))
671 : 0 : goto slow_positive;
672 : :
673 [ + + ]: 763830 : if (!IS_ROOT(dentry)) {
674 : 737340 : parent = dentry->d_parent;
675 [ - + ]: 737340 : if (unlikely(!spin_trylock(&parent->d_lock))) {
676 : 0 : parent = __lock_parent(dentry);
677 [ # # # # ]: 0 : if (likely(inode || !dentry->d_inode))
678 : 0 : goto got_locks;
679 : : /* negative that became positive */
680 [ # # ]: 0 : if (parent)
681 : 0 : spin_unlock(&parent->d_lock);
682 : 0 : inode = dentry->d_inode;
683 : 0 : goto slow_positive;
684 : : }
685 : : }
686 : 763830 : __dentry_kill(dentry);
687 : 763830 : return parent;
688 : :
689 : 0 : slow_positive:
690 : 0 : spin_unlock(&dentry->d_lock);
691 : 0 : spin_lock(&inode->i_lock);
692 : 0 : spin_lock(&dentry->d_lock);
693 : 0 : parent = lock_parent(dentry);
694 : 0 : got_locks:
695 [ # # ]: 0 : if (unlikely(dentry->d_lockref.count != 1)) {
696 : 0 : dentry->d_lockref.count--;
697 [ # # ]: 0 : } else if (likely(!retain_dentry(dentry))) {
698 : 0 : __dentry_kill(dentry);
699 : 0 : return parent;
700 : : }
701 : : /* we are keeping it, after all */
702 [ # # ]: 0 : if (inode)
703 : 0 : spin_unlock(&inode->i_lock);
704 [ # # ]: 0 : if (parent)
705 : 0 : spin_unlock(&parent->d_lock);
706 : 0 : spin_unlock(&dentry->d_lock);
707 : 0 : return NULL;
708 : : }
709 : :
710 : : /*
711 : : * Try to do a lockless dput(), and return whether that was successful.
712 : : *
713 : : * If unsuccessful, we return false, having already taken the dentry lock.
714 : : *
715 : : * The caller needs to hold the RCU read lock, so that the dentry is
716 : : * guaranteed to stay around even if the refcount goes down to zero!
717 : : */
718 : 16628296 : static inline bool fast_dput(struct dentry *dentry)
719 : : {
720 : 16628296 : int ret;
721 : 16628296 : unsigned int d_flags;
722 : :
723 : : /*
724 : : * If we have a d_op->d_delete() operation, we sould not
725 : : * let the dentry count go to zero, so use "put_or_lock".
726 : : */
727 [ + + ]: 16628296 : if (unlikely(dentry->d_flags & DCACHE_OP_DELETE))
728 : 3446663 : return lockref_put_or_lock(&dentry->d_lockref);
729 : :
730 : : /*
731 : : * .. otherwise, we can try to just decrement the
732 : : * lockref optimistically.
733 : : */
734 : 13181633 : ret = lockref_put_return(&dentry->d_lockref);
735 : :
736 : : /*
737 : : * If the lockref_put_return() failed due to the lock being held
738 : : * by somebody else, the fast path has failed. We will need to
739 : : * get the lock, and then check the count again.
740 : : */
741 [ - + ]: 13181633 : if (unlikely(ret < 0)) {
742 : 0 : spin_lock(&dentry->d_lock);
743 [ # # ]: 0 : if (dentry->d_lockref.count > 1) {
744 : 0 : dentry->d_lockref.count--;
745 : 0 : spin_unlock(&dentry->d_lock);
746 : 0 : return true;
747 : : }
748 : : return false;
749 : : }
750 : :
751 : : /*
752 : : * If we weren't the last ref, we're done.
753 : : */
754 [ + + ]: 13181633 : if (ret)
755 : : return true;
756 : :
757 : : /*
758 : : * Careful, careful. The reference count went down
759 : : * to zero, but we don't hold the dentry lock, so
760 : : * somebody else could get it again, and do another
761 : : * dput(), and we need to not race with that.
762 : : *
763 : : * However, there is a very special and common case
764 : : * where we don't care, because there is nothing to
765 : : * do: the dentry is still hashed, it does not have
766 : : * a 'delete' op, and it's referenced and already on
767 : : * the LRU list.
768 : : *
769 : : * NOTE! Since we aren't locked, these values are
770 : : * not "stable". However, it is sufficient that at
771 : : * some point after we dropped the reference the
772 : : * dentry was hashed and the flags had the proper
773 : : * value. Other dentry users may have re-gotten
774 : : * a reference to the dentry and change that, but
775 : : * our work is done - we can leave the dentry
776 : : * around with a zero refcount.
777 : : */
778 : 1103842 : smp_rmb();
779 [ + + ]: 1103842 : d_flags = READ_ONCE(dentry->d_flags);
780 : 1103842 : d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST | DCACHE_DISCONNECTED;
781 : :
782 : : /* Nothing to do? Dropping the reference was all we needed? */
783 [ + + + + ]: 1103842 : if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry))
784 : : return true;
785 : :
786 : : /*
787 : : * Not the fast normal case? Get the lock. We've already decremented
788 : : * the refcount, but we'll need to re-check the situation after
789 : : * getting the lock.
790 : : */
791 : 708581 : spin_lock(&dentry->d_lock);
792 : :
793 : : /*
794 : : * Did somebody else grab a reference to it in the meantime, and
795 : : * we're no longer the last user after all? Alternatively, somebody
796 : : * else could have killed it and marked it dead. Either way, we
797 : : * don't need to do anything else.
798 : : */
799 [ - + ]: 708581 : if (dentry->d_lockref.count) {
800 : 0 : spin_unlock(&dentry->d_lock);
801 : 0 : return true;
802 : : }
803 : :
804 : : /*
805 : : * Re-get the reference we optimistically dropped. We hold the
806 : : * lock, and we just tested that it was zero, so we can just
807 : : * set it to 1.
808 : : */
809 : 708581 : dentry->d_lockref.count = 1;
810 : 708581 : return false;
811 : : }
812 : :
813 : :
814 : : /*
815 : : * This is dput
816 : : *
817 : : * This is complicated by the fact that we do not want to put
818 : : * dentries that are no longer on any hash chain on the unused
819 : : * list: we'd much rather just get rid of them immediately.
820 : : *
821 : : * However, that implies that we have to traverse the dentry
822 : : * tree upwards to the parents which might _also_ now be
823 : : * scheduled for deletion (it may have been only waiting for
824 : : * its last child to go away).
825 : : *
826 : : * This tail recursion is done by hand as we don't want to depend
827 : : * on the compiler to always get this right (gcc generally doesn't).
828 : : * Real recursion would eat up our stack space.
829 : : */
830 : :
831 : : /*
832 : : * dput - release a dentry
833 : : * @dentry: dentry to release
834 : : *
835 : : * Release a dentry. This will drop the usage count and if appropriate
836 : : * call the dentry unlink method as well as removing it from the queues and
837 : : * releasing its resources. If the parent dentries were scheduled for release
838 : : * they too may now get deleted.
839 : : */
840 : 19051845 : void dput(struct dentry *dentry)
841 : : {
842 [ + + ]: 19815675 : while (dentry) {
843 : 16624786 : might_sleep();
844 : :
845 : 16624786 : rcu_read_lock();
846 [ + + ]: 16624786 : if (likely(fast_dput(dentry))) {
847 : 15245732 : rcu_read_unlock();
848 : 15245732 : return;
849 : : }
850 : :
851 : : /* Slow case: now with the dentry lock held */
852 : 1379054 : rcu_read_unlock();
853 : :
854 [ + + ]: 1379054 : if (likely(retain_dentry(dentry))) {
855 : 615224 : spin_unlock(&dentry->d_lock);
856 : 615224 : return;
857 : : }
858 : :
859 : 763830 : dentry = dentry_kill(dentry);
860 : : }
861 : : }
862 : : EXPORT_SYMBOL(dput);
863 : :
864 : 130208 : static void __dput_to_list(struct dentry *dentry, struct list_head *list)
865 : : __must_hold(&dentry->d_lock)
866 : : {
867 [ - + ]: 130208 : if (dentry->d_flags & DCACHE_SHRINK_LIST) {
868 : : /* let the owner of the list it's on deal with it */
869 : 0 : --dentry->d_lockref.count;
870 : : } else {
871 [ + + ]: 130208 : if (dentry->d_flags & DCACHE_LRU_LIST)
872 : 78 : d_lru_del(dentry);
873 [ + + ]: 130208 : if (!--dentry->d_lockref.count)
874 [ - + ]: 5074 : d_shrink_add(dentry, list);
875 : : }
876 : 130208 : }
877 : :
878 : 3510 : void dput_to_list(struct dentry *dentry, struct list_head *list)
879 : : {
880 : 3510 : rcu_read_lock();
881 [ + + ]: 3510 : if (likely(fast_dput(dentry))) {
882 : 3432 : rcu_read_unlock();
883 : 3432 : return;
884 : : }
885 : 78 : rcu_read_unlock();
886 [ - + ]: 78 : if (!retain_dentry(dentry))
887 : 0 : __dput_to_list(dentry, list);
888 : 78 : spin_unlock(&dentry->d_lock);
889 : : }
890 : :
891 : : /* This must be called with d_lock held */
892 : 2304074 : static inline void __dget_dlock(struct dentry *dentry)
893 : : {
894 : 2304074 : dentry->d_lockref.count++;
895 : : }
896 : :
897 : 0 : static inline void __dget(struct dentry *dentry)
898 : : {
899 : 0 : lockref_get(&dentry->d_lockref);
900 : : }
901 : :
902 : 226372 : struct dentry *dget_parent(struct dentry *dentry)
903 : : {
904 : 226372 : int gotref;
905 : 226372 : struct dentry *ret;
906 : 226372 : unsigned seq;
907 : :
908 : : /*
909 : : * Do optimistic parent lookup without any
910 : : * locking.
911 : : */
912 : 226372 : rcu_read_lock();
913 : 226372 : seq = raw_seqcount_begin(&dentry->d_seq);
914 : 226372 : ret = READ_ONCE(dentry->d_parent);
915 : 226372 : gotref = lockref_get_not_zero(&ret->d_lockref);
916 : 226372 : rcu_read_unlock();
917 [ - + ]: 226372 : if (likely(gotref)) {
918 [ - + ]: 226372 : if (!read_seqcount_retry(&dentry->d_seq, seq))
919 : : return ret;
920 : 0 : dput(ret);
921 : : }
922 : :
923 : 0 : repeat:
924 : : /*
925 : : * Don't need rcu_dereference because we re-check it was correct under
926 : : * the lock.
927 : : */
928 : 0 : rcu_read_lock();
929 : 0 : ret = dentry->d_parent;
930 : 0 : spin_lock(&ret->d_lock);
931 [ # # ]: 0 : if (unlikely(ret != dentry->d_parent)) {
932 : 0 : spin_unlock(&ret->d_lock);
933 : 0 : rcu_read_unlock();
934 : 0 : goto repeat;
935 : : }
936 : 0 : rcu_read_unlock();
937 [ # # ]: 0 : BUG_ON(!ret->d_lockref.count);
938 : 0 : ret->d_lockref.count++;
939 : 0 : spin_unlock(&ret->d_lock);
940 : 0 : return ret;
941 : : }
942 : : EXPORT_SYMBOL(dget_parent);
943 : :
944 : 89690 : static struct dentry * __d_find_any_alias(struct inode *inode)
945 : : {
946 : 89690 : struct dentry *alias;
947 : :
948 : 89690 : if (hlist_empty(&inode->i_dentry))
949 : : return NULL;
950 : 0 : alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
951 : 0 : __dget(alias);
952 : 0 : return alias;
953 : : }
954 : :
955 : : /**
956 : : * d_find_any_alias - find any alias for a given inode
957 : : * @inode: inode to find an alias for
958 : : *
959 : : * If any aliases exist for the given inode, take and return a
960 : : * reference for one of them. If no aliases exist, return %NULL.
961 : : */
962 : 0 : struct dentry *d_find_any_alias(struct inode *inode)
963 : : {
964 : 0 : struct dentry *de;
965 : :
966 : 0 : spin_lock(&inode->i_lock);
967 [ # # ]: 0 : de = __d_find_any_alias(inode);
968 : 0 : spin_unlock(&inode->i_lock);
969 : 0 : return de;
970 : : }
971 : : EXPORT_SYMBOL(d_find_any_alias);
972 : :
973 : : /**
974 : : * d_find_alias - grab a hashed alias of inode
975 : : * @inode: inode in question
976 : : *
977 : : * If inode has a hashed alias, or is a directory and has any alias,
978 : : * acquire the reference to alias and return it. Otherwise return NULL.
979 : : * Notice that if inode is a directory there can be only one alias and
980 : : * it can be unhashed only if it has no children, or if it is the root
981 : : * of a filesystem, or if the directory was renamed and d_revalidate
982 : : * was the first vfs operation to notice.
983 : : *
984 : : * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
985 : : * any other hashed alias over that one.
986 : : */
987 : 0 : static struct dentry *__d_find_alias(struct inode *inode)
988 : : {
989 : 0 : struct dentry *alias;
990 : :
991 [ # # ]: 0 : if (S_ISDIR(inode->i_mode))
992 [ # # ]: 0 : return __d_find_any_alias(inode);
993 : :
994 [ # # # # : 0 : hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
# # ]
995 : 0 : spin_lock(&alias->d_lock);
996 [ # # ]: 0 : if (!d_unhashed(alias)) {
997 : 0 : __dget_dlock(alias);
998 : 0 : spin_unlock(&alias->d_lock);
999 : 0 : return alias;
1000 : : }
1001 : 0 : spin_unlock(&alias->d_lock);
1002 : : }
1003 : : return NULL;
1004 : : }
1005 : :
1006 : 0 : struct dentry *d_find_alias(struct inode *inode)
1007 : : {
1008 : 0 : struct dentry *de = NULL;
1009 : :
1010 [ # # ]: 0 : if (!hlist_empty(&inode->i_dentry)) {
1011 : 0 : spin_lock(&inode->i_lock);
1012 : 0 : de = __d_find_alias(inode);
1013 : 0 : spin_unlock(&inode->i_lock);
1014 : : }
1015 : 0 : return de;
1016 : : }
1017 : : EXPORT_SYMBOL(d_find_alias);
1018 : :
1019 : : /*
1020 : : * Try to kill dentries associated with this inode.
1021 : : * WARNING: you must own a reference to inode.
1022 : : */
1023 : 0 : void d_prune_aliases(struct inode *inode)
1024 : : {
1025 : 0 : struct dentry *dentry;
1026 : 0 : restart:
1027 : 0 : spin_lock(&inode->i_lock);
1028 [ # # # # : 0 : hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
# # ]
1029 : 0 : spin_lock(&dentry->d_lock);
1030 [ # # ]: 0 : if (!dentry->d_lockref.count) {
1031 : 0 : struct dentry *parent = lock_parent(dentry);
1032 [ # # ]: 0 : if (likely(!dentry->d_lockref.count)) {
1033 : 0 : __dentry_kill(dentry);
1034 : 0 : dput(parent);
1035 : 0 : goto restart;
1036 : : }
1037 [ # # ]: 0 : if (parent)
1038 : 0 : spin_unlock(&parent->d_lock);
1039 : : }
1040 : 0 : spin_unlock(&dentry->d_lock);
1041 : : }
1042 : 0 : spin_unlock(&inode->i_lock);
1043 : 0 : }
1044 : : EXPORT_SYMBOL(d_prune_aliases);
1045 : :
1046 : : /*
1047 : : * Lock a dentry from shrink list.
1048 : : * Called under rcu_read_lock() and dentry->d_lock; the former
1049 : : * guarantees that nothing we access will be freed under us.
1050 : : * Note that dentry is *not* protected from concurrent dentry_kill(),
1051 : : * d_delete(), etc.
1052 : : *
1053 : : * Return false if dentry has been disrupted or grabbed, leaving
1054 : : * the caller to kick it off-list. Otherwise, return true and have
1055 : : * that dentry's inode and parent both locked.
1056 : : */
1057 : 132981 : static bool shrink_lock_dentry(struct dentry *dentry)
1058 : : {
1059 : 132981 : struct inode *inode;
1060 : 132981 : struct dentry *parent;
1061 : :
1062 [ + + ]: 132981 : if (dentry->d_lockref.count)
1063 : : return false;
1064 : :
1065 : 130208 : inode = dentry->d_inode;
1066 [ + + - + ]: 254339 : if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
1067 : 0 : spin_unlock(&dentry->d_lock);
1068 : 0 : spin_lock(&inode->i_lock);
1069 : 0 : spin_lock(&dentry->d_lock);
1070 [ # # ]: 0 : if (unlikely(dentry->d_lockref.count))
1071 : 0 : goto out;
1072 : : /* changed inode means that somebody had grabbed it */
1073 [ # # ]: 0 : if (unlikely(inode != dentry->d_inode))
1074 : 0 : goto out;
1075 : : }
1076 : :
1077 : 130208 : parent = dentry->d_parent;
1078 [ + - + - ]: 260416 : if (IS_ROOT(dentry) || likely(spin_trylock(&parent->d_lock)))
1079 : 130208 : return true;
1080 : :
1081 : 0 : spin_unlock(&dentry->d_lock);
1082 : 0 : spin_lock(&parent->d_lock);
1083 [ # # ]: 0 : if (unlikely(parent != dentry->d_parent)) {
1084 : 0 : spin_unlock(&parent->d_lock);
1085 : 0 : spin_lock(&dentry->d_lock);
1086 : 0 : goto out;
1087 : : }
1088 : 0 : spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
1089 [ # # ]: 0 : if (likely(!dentry->d_lockref.count))
1090 : : return true;
1091 : 0 : spin_unlock(&parent->d_lock);
1092 : 0 : out:
1093 [ # # ]: 0 : if (inode)
1094 : 0 : spin_unlock(&inode->i_lock);
1095 : : return false;
1096 : : }
1097 : :
1098 : 12531 : void shrink_dentry_list(struct list_head *list)
1099 : : {
1100 [ + + ]: 145512 : while (!list_empty(list)) {
1101 : 132981 : struct dentry *dentry, *parent;
1102 : :
1103 : 132981 : dentry = list_entry(list->prev, struct dentry, d_lru);
1104 : 132981 : spin_lock(&dentry->d_lock);
1105 : 132981 : rcu_read_lock();
1106 [ + + ]: 132981 : if (!shrink_lock_dentry(dentry)) {
1107 : 2773 : bool can_free = false;
1108 : 2773 : rcu_read_unlock();
1109 : 2773 : d_shrink_del(dentry);
1110 [ - + ]: 2773 : if (dentry->d_lockref.count < 0)
1111 : 0 : can_free = dentry->d_flags & DCACHE_MAY_FREE;
1112 : 2773 : spin_unlock(&dentry->d_lock);
1113 [ - + ]: 2773 : if (can_free)
1114 : 0 : dentry_free(dentry);
1115 : 2773 : continue;
1116 : : }
1117 : 130208 : rcu_read_unlock();
1118 : 130208 : d_shrink_del(dentry);
1119 : 130208 : parent = dentry->d_parent;
1120 [ + - ]: 130208 : if (parent != dentry)
1121 : 130208 : __dput_to_list(parent, list);
1122 : 130208 : __dentry_kill(dentry);
1123 : : }
1124 : 12531 : }
1125 : :
1126 : 0 : static enum lru_status dentry_lru_isolate(struct list_head *item,
1127 : : struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
1128 : : {
1129 : 0 : struct list_head *freeable = arg;
1130 : 0 : struct dentry *dentry = container_of(item, struct dentry, d_lru);
1131 : :
1132 : :
1133 : : /*
1134 : : * we are inverting the lru lock/dentry->d_lock here,
1135 : : * so use a trylock. If we fail to get the lock, just skip
1136 : : * it
1137 : : */
1138 [ # # ]: 0 : if (!spin_trylock(&dentry->d_lock))
1139 : : return LRU_SKIP;
1140 : :
1141 : : /*
1142 : : * Referenced dentries are still in use. If they have active
1143 : : * counts, just remove them from the LRU. Otherwise give them
1144 : : * another pass through the LRU.
1145 : : */
1146 [ # # ]: 0 : if (dentry->d_lockref.count) {
1147 : 0 : d_lru_isolate(lru, dentry);
1148 : 0 : spin_unlock(&dentry->d_lock);
1149 : 0 : return LRU_REMOVED;
1150 : : }
1151 : :
1152 [ # # ]: 0 : if (dentry->d_flags & DCACHE_REFERENCED) {
1153 : 0 : dentry->d_flags &= ~DCACHE_REFERENCED;
1154 : 0 : spin_unlock(&dentry->d_lock);
1155 : :
1156 : : /*
1157 : : * The list move itself will be made by the common LRU code. At
1158 : : * this point, we've dropped the dentry->d_lock but keep the
1159 : : * lru lock. This is safe to do, since every list movement is
1160 : : * protected by the lru lock even if both locks are held.
1161 : : *
1162 : : * This is guaranteed by the fact that all LRU management
1163 : : * functions are intermediated by the LRU API calls like
1164 : : * list_lru_add and list_lru_del. List movement in this file
1165 : : * only ever occur through this functions or through callbacks
1166 : : * like this one, that are called from the LRU API.
1167 : : *
1168 : : * The only exceptions to this are functions like
1169 : : * shrink_dentry_list, and code that first checks for the
1170 : : * DCACHE_SHRINK_LIST flag. Those are guaranteed to be
1171 : : * operating only with stack provided lists after they are
1172 : : * properly isolated from the main list. It is thus, always a
1173 : : * local access.
1174 : : */
1175 : 0 : return LRU_ROTATE;
1176 : : }
1177 : :
1178 : 0 : d_lru_shrink_move(lru, dentry, freeable);
1179 : 0 : spin_unlock(&dentry->d_lock);
1180 : :
1181 : 0 : return LRU_REMOVED;
1182 : : }
1183 : :
1184 : : /**
1185 : : * prune_dcache_sb - shrink the dcache
1186 : : * @sb: superblock
1187 : : * @sc: shrink control, passed to list_lru_shrink_walk()
1188 : : *
1189 : : * Attempt to shrink the superblock dcache LRU by @sc->nr_to_scan entries. This
1190 : : * is done when we need more memory and called from the superblock shrinker
1191 : : * function.
1192 : : *
1193 : : * This function may fail to free any resources if all the dentries are in
1194 : : * use.
1195 : : */
1196 : 0 : long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc)
1197 : : {
1198 : 0 : LIST_HEAD(dispose);
1199 : 0 : long freed;
1200 : :
1201 : 0 : freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc,
1202 : : dentry_lru_isolate, &dispose);
1203 : 0 : shrink_dentry_list(&dispose);
1204 : 0 : return freed;
1205 : : }
1206 : :
1207 : 27391 : static enum lru_status dentry_lru_isolate_shrink(struct list_head *item,
1208 : : struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
1209 : : {
1210 : 27391 : struct list_head *freeable = arg;
1211 : 27391 : struct dentry *dentry = container_of(item, struct dentry, d_lru);
1212 : :
1213 : : /*
1214 : : * we are inverting the lru lock/dentry->d_lock here,
1215 : : * so use a trylock. If we fail to get the lock, just skip
1216 : : * it
1217 : : */
1218 [ + - ]: 27391 : if (!spin_trylock(&dentry->d_lock))
1219 : : return LRU_SKIP;
1220 : :
1221 : 27391 : d_lru_shrink_move(lru, dentry, freeable);
1222 : 27391 : spin_unlock(&dentry->d_lock);
1223 : :
1224 : 27391 : return LRU_REMOVED;
1225 : : }
1226 : :
1227 : :
1228 : : /**
1229 : : * shrink_dcache_sb - shrink dcache for a superblock
1230 : : * @sb: superblock
1231 : : *
1232 : : * Shrink the dcache for the specified super block. This is used to free
1233 : : * the dcache before unmounting a file system.
1234 : : */
1235 : 312 : void shrink_dcache_sb(struct super_block *sb)
1236 : : {
1237 : 350 : do {
1238 : 350 : LIST_HEAD(dispose);
1239 : :
1240 : 350 : list_lru_walk(&sb->s_dentry_lru,
1241 : : dentry_lru_isolate_shrink, &dispose, 1024);
1242 : 350 : shrink_dentry_list(&dispose);
1243 [ + + ]: 350 : } while (list_lru_count(&sb->s_dentry_lru) > 0);
1244 : 312 : }
1245 : : EXPORT_SYMBOL(shrink_dcache_sb);
1246 : :
1247 : : /**
1248 : : * enum d_walk_ret - action to talke during tree walk
1249 : : * @D_WALK_CONTINUE: contrinue walk
1250 : : * @D_WALK_QUIT: quit walk
1251 : : * @D_WALK_NORETRY: quit when retry is needed
1252 : : * @D_WALK_SKIP: skip this dentry and its children
1253 : : */
1254 : : enum d_walk_ret {
1255 : : D_WALK_CONTINUE,
1256 : : D_WALK_QUIT,
1257 : : D_WALK_NORETRY,
1258 : : D_WALK_SKIP,
1259 : : };
1260 : :
1261 : : /**
1262 : : * d_walk - walk the dentry tree
1263 : : * @parent: start of walk
1264 : : * @data: data passed to @enter() and @finish()
1265 : : * @enter: callback when first entering the dentry
1266 : : *
1267 : : * The @enter() callbacks are called with d_lock held.
1268 : : */
1269 : 16223 : static void d_walk(struct dentry *parent, void *data,
1270 : : enum d_walk_ret (*enter)(void *, struct dentry *))
1271 : : {
1272 : 16223 : struct dentry *this_parent;
1273 : 16223 : struct list_head *next;
1274 : 16223 : unsigned seq = 0;
1275 : 16223 : enum d_walk_ret ret;
1276 : 16223 : bool retry = true;
1277 : :
1278 : 16223 : again:
1279 : 16223 : read_seqbegin_or_lock(&rename_lock, &seq);
1280 : 16223 : this_parent = parent;
1281 : 16223 : spin_lock(&this_parent->d_lock);
1282 : :
1283 : 16223 : ret = enter(data, this_parent);
1284 [ - - + ]: 16223 : switch (ret) {
1285 : : case D_WALK_CONTINUE:
1286 : : break;
1287 : 0 : case D_WALK_QUIT:
1288 : : case D_WALK_SKIP:
1289 : 0 : goto out_unlock;
1290 : 0 : case D_WALK_NORETRY:
1291 : 0 : retry = false;
1292 : 0 : break;
1293 : : }
1294 : : repeat:
1295 : 18694 : next = this_parent->d_subdirs.next;
1296 : : resume:
1297 [ + + ]: 120405 : while (next != &this_parent->d_subdirs) {
1298 : 102987 : struct list_head *tmp = next;
1299 : 102987 : struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
1300 : 102987 : next = tmp->next;
1301 : :
1302 [ - + ]: 102987 : if (unlikely(dentry->d_flags & DCACHE_DENTRY_CURSOR))
1303 : 0 : continue;
1304 : :
1305 : 102987 : spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
1306 : :
1307 : 102987 : ret = enter(data, dentry);
1308 [ + + - + ]: 102987 : switch (ret) {
1309 : : case D_WALK_CONTINUE:
1310 : : break;
1311 : 20 : case D_WALK_QUIT:
1312 : 20 : spin_unlock(&dentry->d_lock);
1313 : 20 : goto out_unlock;
1314 : 102570 : case D_WALK_NORETRY:
1315 : 102570 : retry = false;
1316 : 102570 : break;
1317 : 0 : case D_WALK_SKIP:
1318 : 0 : spin_unlock(&dentry->d_lock);
1319 : 0 : continue;
1320 : : }
1321 : :
1322 [ + + ]: 102967 : if (!list_empty(&dentry->d_subdirs)) {
1323 : 2471 : spin_unlock(&this_parent->d_lock);
1324 : 2471 : spin_release(&dentry->d_lock.dep_map, _RET_IP_);
1325 : 2471 : this_parent = dentry;
1326 : 2471 : spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
1327 : 2471 : goto repeat;
1328 : : }
1329 : 100496 : spin_unlock(&dentry->d_lock);
1330 : : }
1331 : : /*
1332 : : * All done at this level ... ascend and resume the search.
1333 : : */
1334 : 17418 : rcu_read_lock();
1335 : 18657 : ascend:
1336 [ + + ]: 18657 : if (this_parent != parent) {
1337 : 2454 : struct dentry *child = this_parent;
1338 : 2454 : this_parent = child->d_parent;
1339 : :
1340 : 2454 : spin_unlock(&child->d_lock);
1341 : 2454 : spin_lock(&this_parent->d_lock);
1342 : :
1343 : : /* might go back up the wrong parent if we have had a rename. */
1344 [ + - ]: 2454 : if (need_seqretry(&rename_lock, seq))
1345 : 0 : goto rename_retry;
1346 : : /* go into the first sibling still alive */
1347 : 2454 : do {
1348 : 2454 : next = child->d_child.next;
1349 [ + + ]: 2454 : if (next == &this_parent->d_subdirs)
1350 : 1239 : goto ascend;
1351 : 1215 : child = list_entry(next, struct dentry, d_child);
1352 [ - + ]: 1215 : } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
1353 : 1215 : rcu_read_unlock();
1354 : 1215 : goto resume;
1355 : : }
1356 [ + - ]: 16203 : if (need_seqretry(&rename_lock, seq))
1357 : 0 : goto rename_retry;
1358 : 16203 : rcu_read_unlock();
1359 : :
1360 : 16223 : out_unlock:
1361 : 16223 : spin_unlock(&this_parent->d_lock);
1362 [ - + ]: 16223 : done_seqretry(&rename_lock, seq);
1363 : : return;
1364 : :
1365 : 0 : rename_retry:
1366 : 0 : spin_unlock(&this_parent->d_lock);
1367 : 0 : rcu_read_unlock();
1368 [ # # ]: 0 : BUG_ON(seq & 1);
1369 [ # # ]: 0 : if (!retry)
1370 : : return;
1371 : 0 : seq = 1;
1372 : 0 : goto again;
1373 : : }
1374 : :
1375 : : struct check_mount {
1376 : : struct vfsmount *mnt;
1377 : : unsigned int mounted;
1378 : : };
1379 : :
1380 : 0 : static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry)
1381 : : {
1382 : 0 : struct check_mount *info = data;
1383 : 0 : struct path path = { .mnt = info->mnt, .dentry = dentry };
1384 : :
1385 [ # # ]: 0 : if (likely(!d_mountpoint(dentry)))
1386 : : return D_WALK_CONTINUE;
1387 [ # # ]: 0 : if (__path_is_mountpoint(&path)) {
1388 : 0 : info->mounted = 1;
1389 : 0 : return D_WALK_QUIT;
1390 : : }
1391 : : return D_WALK_CONTINUE;
1392 : : }
1393 : :
1394 : : /**
1395 : : * path_has_submounts - check for mounts over a dentry in the
1396 : : * current namespace.
1397 : : * @parent: path to check.
1398 : : *
1399 : : * Return true if the parent or its subdirectories contain
1400 : : * a mount point in the current namespace.
1401 : : */
1402 : 0 : int path_has_submounts(const struct path *parent)
1403 : : {
1404 : 0 : struct check_mount data = { .mnt = parent->mnt, .mounted = 0 };
1405 : :
1406 : 0 : read_seqlock_excl(&mount_lock);
1407 : 0 : d_walk(parent->dentry, &data, path_check_mount);
1408 : 0 : read_sequnlock_excl(&mount_lock);
1409 : :
1410 : 0 : return data.mounted;
1411 : : }
1412 : : EXPORT_SYMBOL(path_has_submounts);
1413 : :
1414 : : /*
1415 : : * Called by mount code to set a mountpoint and check if the mountpoint is
1416 : : * reachable (e.g. NFS can unhash a directory dentry and then the complete
1417 : : * subtree can become unreachable).
1418 : : *
1419 : : * Only one of d_invalidate() and d_set_mounted() must succeed. For
1420 : : * this reason take rename_lock and d_lock on dentry and ancestors.
1421 : : */
1422 : 7176 : int d_set_mounted(struct dentry *dentry)
1423 : : {
1424 : 7176 : struct dentry *p;
1425 : 7176 : int ret = -ENOENT;
1426 : 7176 : write_seqlock(&rename_lock);
1427 [ + + ]: 9828 : for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
1428 : : /* Need exclusion wrt. d_invalidate() */
1429 : 2652 : spin_lock(&p->d_lock);
1430 [ - + ]: 2652 : if (unlikely(d_unhashed(p))) {
1431 : 0 : spin_unlock(&p->d_lock);
1432 : 0 : goto out;
1433 : : }
1434 : 2652 : spin_unlock(&p->d_lock);
1435 : : }
1436 : 7176 : spin_lock(&dentry->d_lock);
1437 [ + + ]: 7176 : if (!d_unlinked(dentry)) {
1438 : 7176 : ret = -EBUSY;
1439 [ + - ]: 7176 : if (!d_mountpoint(dentry)) {
1440 : 7176 : dentry->d_flags |= DCACHE_MOUNTED;
1441 : 7176 : ret = 0;
1442 : : }
1443 : : }
1444 : 7176 : spin_unlock(&dentry->d_lock);
1445 : 7176 : out:
1446 : 7176 : write_sequnlock(&rename_lock);
1447 : 7176 : return ret;
1448 : : }
1449 : :
1450 : : /*
1451 : : * Search the dentry child list of the specified parent,
1452 : : * and move any unused dentries to the end of the unused
1453 : : * list for prune_dcache(). We descend to the next level
1454 : : * whenever the d_subdirs list is non-empty and continue
1455 : : * searching.
1456 : : *
1457 : : * It returns zero iff there are no unused children,
1458 : : * otherwise it returns the number of children moved to
1459 : : * the end of the unused list. This may not be the total
1460 : : * number of unused children, because select_parent can
1461 : : * drop the lock and return early due to latency
1462 : : * constraints.
1463 : : */
1464 : :
1465 : : struct select_data {
1466 : : struct dentry *start;
1467 : : union {
1468 : : long found;
1469 : : struct dentry *victim;
1470 : : };
1471 : : struct list_head dispose;
1472 : : };
1473 : :
1474 : 115317 : static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
1475 : : {
1476 : 115317 : struct select_data *data = _data;
1477 : 115317 : enum d_walk_ret ret = D_WALK_CONTINUE;
1478 : :
1479 [ + + ]: 115317 : if (data->start == dentry)
1480 : 12330 : goto out;
1481 : :
1482 [ - + ]: 102987 : if (dentry->d_flags & DCACHE_SHRINK_LIST) {
1483 : 0 : data->found++;
1484 : : } else {
1485 [ + + ]: 102987 : if (dentry->d_flags & DCACHE_LRU_LIST)
1486 : 100516 : d_lru_del(dentry);
1487 [ + + ]: 102987 : if (!dentry->d_lockref.count) {
1488 [ - + ]: 100516 : d_shrink_add(dentry, &data->dispose);
1489 : 100516 : data->found++;
1490 : : }
1491 : : }
1492 : : /*
1493 : : * We can return to the caller if we have found some (this
1494 : : * ensures forward progress). We'll be coming back to find
1495 : : * the rest.
1496 : : */
1497 [ + + ]: 102987 : if (!list_empty(&data->dispose))
1498 [ + + ]: 102590 : ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
1499 : 397 : out:
1500 : 115317 : return ret;
1501 : : }
1502 : :
1503 : 0 : static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
1504 : : {
1505 : 0 : struct select_data *data = _data;
1506 : 0 : enum d_walk_ret ret = D_WALK_CONTINUE;
1507 : :
1508 [ # # ]: 0 : if (data->start == dentry)
1509 : 0 : goto out;
1510 : :
1511 [ # # ]: 0 : if (dentry->d_flags & DCACHE_SHRINK_LIST) {
1512 [ # # ]: 0 : if (!dentry->d_lockref.count) {
1513 : 0 : rcu_read_lock();
1514 : 0 : data->victim = dentry;
1515 : 0 : return D_WALK_QUIT;
1516 : : }
1517 : : } else {
1518 [ # # ]: 0 : if (dentry->d_flags & DCACHE_LRU_LIST)
1519 : 0 : d_lru_del(dentry);
1520 [ # # ]: 0 : if (!dentry->d_lockref.count)
1521 [ # # ]: 0 : d_shrink_add(dentry, &data->dispose);
1522 : : }
1523 : : /*
1524 : : * We can return to the caller if we have found some (this
1525 : : * ensures forward progress). We'll be coming back to find
1526 : : * the rest.
1527 : : */
1528 [ # # ]: 0 : if (!list_empty(&data->dispose))
1529 [ # # ]: 0 : ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
1530 : 0 : out:
1531 : : return ret;
1532 : : }
1533 : :
1534 : : /**
1535 : : * shrink_dcache_parent - prune dcache
1536 : : * @parent: parent of entries to prune
1537 : : *
1538 : : * Prune the dcache to remove unused children of the parent dentry.
1539 : : */
1540 : 6389 : void shrink_dcache_parent(struct dentry *parent)
1541 : : {
1542 : 12330 : for (;;) {
1543 : 12330 : struct select_data data = {.start = parent};
1544 : :
1545 : 12330 : INIT_LIST_HEAD(&data.dispose);
1546 : 12330 : d_walk(parent, &data, select_collect);
1547 : :
1548 [ + + ]: 12330 : if (!list_empty(&data.dispose)) {
1549 : 5941 : shrink_dentry_list(&data.dispose);
1550 : 5941 : continue;
1551 : : }
1552 : :
1553 : 6389 : cond_resched();
1554 [ - + ]: 6389 : if (!data.found)
1555 : : break;
1556 : 0 : data.victim = NULL;
1557 : 0 : d_walk(parent, &data, select_collect2);
1558 [ # # ]: 0 : if (data.victim) {
1559 : 0 : struct dentry *parent;
1560 : 0 : spin_lock(&data.victim->d_lock);
1561 [ # # ]: 0 : if (!shrink_lock_dentry(data.victim)) {
1562 : 0 : spin_unlock(&data.victim->d_lock);
1563 : 0 : rcu_read_unlock();
1564 : : } else {
1565 : 0 : rcu_read_unlock();
1566 : 0 : parent = data.victim->d_parent;
1567 [ # # ]: 0 : if (parent != data.victim)
1568 : 0 : __dput_to_list(parent, &data.dispose);
1569 : 0 : __dentry_kill(data.victim);
1570 : : }
1571 : : }
1572 [ # # ]: 0 : if (!list_empty(&data.dispose))
1573 : 0 : shrink_dentry_list(&data.dispose);
1574 : : }
1575 : 6389 : }
1576 : : EXPORT_SYMBOL(shrink_dcache_parent);
1577 : :
1578 : 0 : static enum d_walk_ret umount_check(void *_data, struct dentry *dentry)
1579 : : {
1580 : : /* it has busy descendents; complain about those instead */
1581 [ # # ]: 0 : if (!list_empty(&dentry->d_subdirs))
1582 : : return D_WALK_CONTINUE;
1583 : :
1584 : : /* root with refcount 1 is fine */
1585 [ # # # # ]: 0 : if (dentry == _data && dentry->d_lockref.count == 1)
1586 : : return D_WALK_CONTINUE;
1587 : :
1588 : 0 : printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%pd} "
1589 : : " still in use (%d) [unmount of %s %s]\n",
1590 : : dentry,
1591 : 0 : dentry->d_inode ?
1592 : : dentry->d_inode->i_ino : 0UL,
1593 : : dentry,
1594 : : dentry->d_lockref.count,
1595 : 0 : dentry->d_sb->s_type->name,
1596 [ # # ]: 0 : dentry->d_sb->s_id);
1597 : 0 : WARN_ON(1);
1598 : : return D_WALK_CONTINUE;
1599 : : }
1600 : :
1601 : 0 : static void do_one_tree(struct dentry *dentry)
1602 : : {
1603 : 0 : shrink_dcache_parent(dentry);
1604 : 0 : d_walk(dentry, dentry, umount_check);
1605 : 0 : d_drop(dentry);
1606 : 0 : dput(dentry);
1607 : 0 : }
1608 : :
1609 : : /*
1610 : : * destroy the dentries attached to a superblock on unmounting
1611 : : */
1612 : 0 : void shrink_dcache_for_umount(struct super_block *sb)
1613 : : {
1614 : 0 : struct dentry *dentry;
1615 : :
1616 [ # # ]: 0 : WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
1617 : :
1618 : 0 : dentry = sb->s_root;
1619 : 0 : sb->s_root = NULL;
1620 : 0 : do_one_tree(dentry);
1621 : :
1622 [ # # ]: 0 : while (!hlist_bl_empty(&sb->s_roots)) {
1623 [ # # ]: 0 : dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash));
1624 : 0 : do_one_tree(dentry);
1625 : : }
1626 : 0 : }
1627 : :
1628 : 3659 : static enum d_walk_ret find_submount(void *_data, struct dentry *dentry)
1629 : : {
1630 : 3659 : struct dentry **victim = _data;
1631 [ - + ]: 3659 : if (d_mountpoint(dentry)) {
1632 : 0 : __dget_dlock(dentry);
1633 : 0 : *victim = dentry;
1634 : 0 : return D_WALK_QUIT;
1635 : : }
1636 : : return D_WALK_CONTINUE;
1637 : : }
1638 : :
1639 : : /**
1640 : : * d_invalidate - detach submounts, prune dcache, and drop
1641 : : * @dentry: dentry to invalidate (aka detach, prune and drop)
1642 : : */
1643 : 3659 : void d_invalidate(struct dentry *dentry)
1644 : : {
1645 : 3659 : bool had_submounts = false;
1646 : 3659 : spin_lock(&dentry->d_lock);
1647 [ - + ]: 3659 : if (d_unhashed(dentry)) {
1648 : 0 : spin_unlock(&dentry->d_lock);
1649 : 0 : return;
1650 : : }
1651 : 3659 : __d_drop(dentry);
1652 : 3659 : spin_unlock(&dentry->d_lock);
1653 : :
1654 : : /* Negative dentries can be dropped without further checks */
1655 [ + - ]: 3659 : if (!dentry->d_inode)
1656 : : return;
1657 : :
1658 : 3659 : shrink_dcache_parent(dentry);
1659 : 0 : for (;;) {
1660 : 3659 : struct dentry *victim = NULL;
1661 : 3659 : d_walk(dentry, &victim, find_submount);
1662 [ + - ]: 3659 : if (!victim) {
1663 [ - + ]: 3659 : if (had_submounts)
1664 : 0 : shrink_dcache_parent(dentry);
1665 : 3659 : return;
1666 : : }
1667 : 0 : had_submounts = true;
1668 [ # # ]: 0 : detach_mounts(victim);
1669 : 0 : dput(victim);
1670 : : }
1671 : : }
1672 : : EXPORT_SYMBOL(d_invalidate);
1673 : :
1674 : : /**
1675 : : * __d_alloc - allocate a dcache entry
1676 : : * @sb: filesystem it will belong to
1677 : : * @name: qstr of the name
1678 : : *
1679 : : * Allocates a dentry. It returns %NULL if there is insufficient memory
1680 : : * available. On a success the dentry is returned. The name passed in is
1681 : : * copied and the copy passed in may be reused after this call.
1682 : : */
1683 : :
1684 : 2364730 : static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
1685 : : {
1686 : 2364730 : struct dentry *dentry;
1687 : 2364730 : char *dname;
1688 : 2364730 : int err;
1689 : :
1690 : 2364730 : dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
1691 [ + - ]: 2364730 : if (!dentry)
1692 : : return NULL;
1693 : :
1694 : : /*
1695 : : * We guarantee that the inline name is always NUL-terminated.
1696 : : * This way the memcpy() done by the name switching in rename
1697 : : * will still always have a NUL at the end, even if we might
1698 : : * be overwriting an internal NUL character
1699 : : */
1700 : 2364730 : dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
1701 [ + + ]: 2364730 : if (unlikely(!name)) {
1702 : 26286 : name = &slash_name;
1703 : 26286 : dname = dentry->d_iname;
1704 [ + + ]: 2338444 : } else if (name->len > DNAME_INLINE_LEN-1) {
1705 : 67143 : size_t size = offsetof(struct external_name, name[1]);
1706 [ - + ]: 67143 : struct external_name *p = kmalloc(size + name->len,
1707 : : GFP_KERNEL_ACCOUNT |
1708 : : __GFP_RECLAIMABLE);
1709 [ - + ]: 67143 : if (!p) {
1710 : 0 : kmem_cache_free(dentry_cache, dentry);
1711 : 0 : return NULL;
1712 : : }
1713 : 67143 : atomic_set(&p->u.count, 1);
1714 : 67143 : dname = p->name;
1715 : : } else {
1716 : 2271301 : dname = dentry->d_iname;
1717 : : }
1718 : :
1719 : 2364730 : dentry->d_name.len = name->len;
1720 : 2364730 : dentry->d_name.hash = name->hash;
1721 : 2364730 : memcpy(dname, name->name, name->len);
1722 : 2364730 : dname[name->len] = 0;
1723 : :
1724 : : /* Make sure we always see the terminating NUL character */
1725 : 2364730 : smp_store_release(&dentry->d_name.name, dname); /* ^^^ */
1726 : :
1727 : 2364730 : dentry->d_lockref.count = 1;
1728 : 2364730 : dentry->d_flags = 0;
1729 : 2364730 : spin_lock_init(&dentry->d_lock);
1730 : 2364730 : seqcount_init(&dentry->d_seq);
1731 : 2364730 : dentry->d_inode = NULL;
1732 : 2364730 : dentry->d_parent = dentry;
1733 : 2364730 : dentry->d_sb = sb;
1734 : 2364730 : dentry->d_op = NULL;
1735 : 2364730 : dentry->d_fsdata = NULL;
1736 : 2364730 : INIT_HLIST_BL_NODE(&dentry->d_hash);
1737 : 2364730 : INIT_LIST_HEAD(&dentry->d_lru);
1738 : 2364730 : INIT_LIST_HEAD(&dentry->d_subdirs);
1739 : 2364730 : INIT_HLIST_NODE(&dentry->d_u.d_alias);
1740 : 2364730 : INIT_LIST_HEAD(&dentry->d_child);
1741 : 2364730 : d_set_d_op(dentry, dentry->d_sb->s_d_op);
1742 : :
1743 [ + + - + ]: 2364730 : if (dentry->d_op && dentry->d_op->d_init) {
1744 : 0 : err = dentry->d_op->d_init(dentry);
1745 [ # # ]: 0 : if (err) {
1746 [ # # ]: 0 : if (dname_external(dentry))
1747 : 0 : kfree(external_name(dentry));
1748 : 0 : kmem_cache_free(dentry_cache, dentry);
1749 : 0 : return NULL;
1750 : : }
1751 : : }
1752 : :
1753 : 2364730 : this_cpu_inc(nr_dentry);
1754 : :
1755 : 2364730 : return dentry;
1756 : : }
1757 : :
1758 : : /**
1759 : : * d_alloc - allocate a dcache entry
1760 : : * @parent: parent of entry to allocate
1761 : : * @name: qstr of the name
1762 : : *
1763 : : * Allocates a dentry. It returns %NULL if there is insufficient memory
1764 : : * available. On a success the dentry is returned. The name passed in is
1765 : : * copied and the copy passed in may be reused after this call.
1766 : : */
1767 : 2304074 : struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
1768 : : {
1769 : 2304074 : struct dentry *dentry = __d_alloc(parent->d_sb, name);
1770 [ + - ]: 2304074 : if (!dentry)
1771 : : return NULL;
1772 : 2304074 : spin_lock(&parent->d_lock);
1773 : : /*
1774 : : * don't need child lock because it is not subject
1775 : : * to concurrency here
1776 : : */
1777 : 2304074 : __dget_dlock(parent);
1778 : 2304074 : dentry->d_parent = parent;
1779 : 2304074 : list_add(&dentry->d_child, &parent->d_subdirs);
1780 : 2304074 : spin_unlock(&parent->d_lock);
1781 : :
1782 : 2304074 : return dentry;
1783 : : }
1784 : : EXPORT_SYMBOL(d_alloc);
1785 : :
1786 : 26286 : struct dentry *d_alloc_anon(struct super_block *sb)
1787 : : {
1788 : 0 : return __d_alloc(sb, NULL);
1789 : : }
1790 : : EXPORT_SYMBOL(d_alloc_anon);
1791 : :
1792 : 23556 : struct dentry *d_alloc_cursor(struct dentry * parent)
1793 : : {
1794 : 23556 : struct dentry *dentry = d_alloc_anon(parent->d_sb);
1795 [ + - ]: 23556 : if (dentry) {
1796 : 23556 : dentry->d_flags |= DCACHE_DENTRY_CURSOR;
1797 [ + - ]: 47112 : dentry->d_parent = dget(parent);
1798 : : }
1799 : 23556 : return dentry;
1800 : : }
1801 : :
1802 : : /**
1803 : : * d_alloc_pseudo - allocate a dentry (for lookup-less filesystems)
1804 : : * @sb: the superblock
1805 : : * @name: qstr of the name
1806 : : *
1807 : : * For a filesystem that just pins its dentries in memory and never
1808 : : * performs lookups at all, return an unhashed IS_ROOT dentry.
1809 : : * This is used for pipes, sockets et.al. - the stuff that should
1810 : : * never be anyone's children or parents. Unlike all other
1811 : : * dentries, these will not have RCU delay between dropping the
1812 : : * last reference and freeing them.
1813 : : *
1814 : : * The only user is alloc_file_pseudo() and that's what should
1815 : : * be considered a public interface. Don't use directly.
1816 : : */
1817 : 34370 : struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
1818 : : {
1819 : 34370 : struct dentry *dentry = __d_alloc(sb, name);
1820 [ + - ]: 34370 : if (likely(dentry))
1821 : 34370 : dentry->d_flags |= DCACHE_NORCU;
1822 : 34370 : return dentry;
1823 : : }
1824 : :
1825 : 5226 : struct dentry *d_alloc_name(struct dentry *parent, const char *name)
1826 : : {
1827 : 5226 : struct qstr q;
1828 : :
1829 : 5226 : q.name = name;
1830 : 5226 : q.hash_len = hashlen_string(parent, name);
1831 : 5226 : return d_alloc(parent, &q);
1832 : : }
1833 : : EXPORT_SYMBOL(d_alloc_name);
1834 : :
1835 : 3619916 : void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
1836 : : {
1837 [ - + ]: 3619916 : WARN_ON_ONCE(dentry->d_op);
1838 [ - + ]: 3619916 : WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH |
1839 : : DCACHE_OP_COMPARE |
1840 : : DCACHE_OP_REVALIDATE |
1841 : : DCACHE_OP_WEAK_REVALIDATE |
1842 : : DCACHE_OP_DELETE |
1843 : : DCACHE_OP_REAL));
1844 : 3619916 : dentry->d_op = op;
1845 [ + + ]: 3619916 : if (!op)
1846 : : return;
1847 [ - + ]: 2193628 : if (op->d_hash)
1848 : 0 : dentry->d_flags |= DCACHE_OP_HASH;
1849 [ + + ]: 2193628 : if (op->d_compare)
1850 : 2340 : dentry->d_flags |= DCACHE_OP_COMPARE;
1851 [ + + ]: 2193628 : if (op->d_revalidate)
1852 : 567074 : dentry->d_flags |= DCACHE_OP_REVALIDATE;
1853 [ - + ]: 2193628 : if (op->d_weak_revalidate)
1854 : 0 : dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE;
1855 [ + + ]: 2193628 : if (op->d_delete)
1856 : 1729660 : dentry->d_flags |= DCACHE_OP_DELETE;
1857 [ - + ]: 2193628 : if (op->d_prune)
1858 : 0 : dentry->d_flags |= DCACHE_OP_PRUNE;
1859 [ - + ]: 2193628 : if (op->d_real)
1860 : 0 : dentry->d_flags |= DCACHE_OP_REAL;
1861 : :
1862 : : }
1863 : : EXPORT_SYMBOL(d_set_d_op);
1864 : :
1865 : :
1866 : : /*
1867 : : * d_set_fallthru - Mark a dentry as falling through to a lower layer
1868 : : * @dentry - The dentry to mark
1869 : : *
1870 : : * Mark a dentry as falling through to the lower layer (as set with
1871 : : * d_pin_lower()). This flag may be recorded on the medium.
1872 : : */
1873 : 0 : void d_set_fallthru(struct dentry *dentry)
1874 : : {
1875 : 0 : spin_lock(&dentry->d_lock);
1876 : 0 : dentry->d_flags |= DCACHE_FALLTHRU;
1877 : 0 : spin_unlock(&dentry->d_lock);
1878 : 0 : }
1879 : : EXPORT_SYMBOL(d_set_fallthru);
1880 : :
1881 : 1583668 : static unsigned d_flags_for_inode(struct inode *inode)
1882 : : {
1883 : 1583668 : unsigned add_flags = DCACHE_REGULAR_TYPE;
1884 : :
1885 [ + - ]: 1583668 : if (!inode)
1886 : : return DCACHE_MISS_TYPE;
1887 : :
1888 [ + + ]: 1583668 : if (S_ISDIR(inode->i_mode)) {
1889 : 247094 : add_flags = DCACHE_DIRECTORY_TYPE;
1890 [ + + ]: 247094 : if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) {
1891 [ + + ]: 245756 : if (unlikely(!inode->i_op->lookup))
1892 : : add_flags = DCACHE_AUTODIR_TYPE;
1893 : : else
1894 : 245210 : inode->i_opflags |= IOP_LOOKUP;
1895 : : }
1896 : 247094 : goto type_determined;
1897 : : }
1898 : :
1899 [ + + ]: 1336574 : if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
1900 [ + + ]: 1329004 : if (unlikely(inode->i_op->get_link)) {
1901 : 375121 : add_flags = DCACHE_SYMLINK_TYPE;
1902 : 375121 : goto type_determined;
1903 : : }
1904 : 953883 : inode->i_opflags |= IOP_NOFOLLOW;
1905 : : }
1906 : :
1907 [ + + ]: 961453 : if (unlikely(!S_ISREG(inode->i_mode)))
1908 : 45992 : add_flags = DCACHE_SPECIAL_TYPE;
1909 : :
1910 : 915461 : type_determined:
1911 [ + + ]: 1583668 : if (unlikely(IS_AUTOMOUNT(inode)))
1912 : 78 : add_flags |= DCACHE_NEED_AUTOMOUNT;
1913 : : return add_flags;
1914 : : }
1915 : :
1916 : 1191415 : static void __d_instantiate(struct dentry *dentry, struct inode *inode)
1917 : : {
1918 : 1191415 : unsigned add_flags = d_flags_for_inode(inode);
1919 [ - + ]: 1191415 : WARN_ON(d_in_lookup(dentry));
1920 : :
1921 : 1191415 : spin_lock(&dentry->d_lock);
1922 : : /*
1923 : : * Decrement negative dentry count if it was in the LRU list.
1924 : : */
1925 [ + + ]: 1191415 : if (dentry->d_flags & DCACHE_LRU_LIST)
1926 : 1191415 : this_cpu_dec(nr_dentry_negative);
1927 [ + + ]: 1191415 : hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
1928 : 1191415 : raw_write_seqcount_begin(&dentry->d_seq);
1929 : 1191415 : __d_set_inode_and_type(dentry, inode, add_flags);
1930 : 1191415 : raw_write_seqcount_end(&dentry->d_seq);
1931 : 1191415 : fsnotify_update_flags(dentry);
1932 : 1191415 : spin_unlock(&dentry->d_lock);
1933 : 1191415 : }
1934 : :
1935 : : /**
1936 : : * d_instantiate - fill in inode information for a dentry
1937 : : * @entry: dentry to complete
1938 : : * @inode: inode to attach to this dentry
1939 : : *
1940 : : * Fill in inode information in the entry.
1941 : : *
1942 : : * This turns negative dentries into productive full members
1943 : : * of society.
1944 : : *
1945 : : * NOTE! This assumes that the inode count has been incremented
1946 : : * (or otherwise set) by the caller to indicate that it is now
1947 : : * in use by the dcache.
1948 : : */
1949 : :
1950 : 1147813 : void d_instantiate(struct dentry *entry, struct inode * inode)
1951 : : {
1952 [ - + ]: 1147813 : BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
1953 [ + - ]: 1147813 : if (inode) {
1954 : 1147813 : security_d_instantiate(entry, inode);
1955 : 1147813 : spin_lock(&inode->i_lock);
1956 : 1147813 : __d_instantiate(entry, inode);
1957 : 1147813 : spin_unlock(&inode->i_lock);
1958 : : }
1959 : 1147813 : }
1960 : : EXPORT_SYMBOL(d_instantiate);
1961 : :
1962 : : /*
1963 : : * This should be equivalent to d_instantiate() + unlock_new_inode(),
1964 : : * with lockdep-related part of unlock_new_inode() done before
1965 : : * anything else. Use that instead of open-coding d_instantiate()/
1966 : : * unlock_new_inode() combinations.
1967 : : */
1968 : 43602 : void d_instantiate_new(struct dentry *entry, struct inode *inode)
1969 : : {
1970 [ - + ]: 43602 : BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
1971 [ - + ]: 43602 : BUG_ON(!inode);
1972 : 43602 : lockdep_annotate_inode_mutex_key(inode);
1973 : 43602 : security_d_instantiate(entry, inode);
1974 : 43602 : spin_lock(&inode->i_lock);
1975 : 43602 : __d_instantiate(entry, inode);
1976 [ - + ]: 43602 : WARN_ON(!(inode->i_state & I_NEW));
1977 : 43602 : inode->i_state &= ~I_NEW & ~I_CREATING;
1978 : 43602 : smp_mb();
1979 : 43602 : wake_up_bit(&inode->i_state, __I_NEW);
1980 : 43602 : spin_unlock(&inode->i_lock);
1981 : 43602 : }
1982 : : EXPORT_SYMBOL(d_instantiate_new);
1983 : :
1984 : 2730 : struct dentry *d_make_root(struct inode *root_inode)
1985 : : {
1986 : 2730 : struct dentry *res = NULL;
1987 : :
1988 [ + - ]: 2730 : if (root_inode) {
1989 : 2730 : res = d_alloc_anon(root_inode->i_sb);
1990 [ + - ]: 2730 : if (res)
1991 : 2730 : d_instantiate(res, root_inode);
1992 : : else
1993 : 0 : iput(root_inode);
1994 : : }
1995 : 2730 : return res;
1996 : : }
1997 : : EXPORT_SYMBOL(d_make_root);
1998 : :
1999 : 0 : static struct dentry *__d_instantiate_anon(struct dentry *dentry,
2000 : : struct inode *inode,
2001 : : bool disconnected)
2002 : : {
2003 : 0 : struct dentry *res;
2004 : 0 : unsigned add_flags;
2005 : :
2006 : 0 : security_d_instantiate(dentry, inode);
2007 : 0 : spin_lock(&inode->i_lock);
2008 [ # # ]: 0 : res = __d_find_any_alias(inode);
2009 [ # # ]: 0 : if (res) {
2010 : 0 : spin_unlock(&inode->i_lock);
2011 : 0 : dput(dentry);
2012 : 0 : goto out_iput;
2013 : : }
2014 : :
2015 : : /* attach a disconnected dentry */
2016 : 0 : add_flags = d_flags_for_inode(inode);
2017 : :
2018 [ # # ]: 0 : if (disconnected)
2019 : 0 : add_flags |= DCACHE_DISCONNECTED;
2020 : :
2021 : 0 : spin_lock(&dentry->d_lock);
2022 : 0 : __d_set_inode_and_type(dentry, inode, add_flags);
2023 [ # # ]: 0 : hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
2024 [ # # ]: 0 : if (!disconnected) {
2025 : 0 : hlist_bl_lock(&dentry->d_sb->s_roots);
2026 [ # # ]: 0 : hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots);
2027 : 0 : hlist_bl_unlock(&dentry->d_sb->s_roots);
2028 : : }
2029 : 0 : spin_unlock(&dentry->d_lock);
2030 : 0 : spin_unlock(&inode->i_lock);
2031 : :
2032 : 0 : return dentry;
2033 : :
2034 : : out_iput:
2035 : 0 : iput(inode);
2036 : 0 : return res;
2037 : : }
2038 : :
2039 : 0 : struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
2040 : : {
2041 : 0 : return __d_instantiate_anon(dentry, inode, true);
2042 : : }
2043 : : EXPORT_SYMBOL(d_instantiate_anon);
2044 : :
2045 : 0 : static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
2046 : : {
2047 : 0 : struct dentry *tmp;
2048 : 0 : struct dentry *res;
2049 : :
2050 [ # # ]: 0 : if (!inode)
2051 : : return ERR_PTR(-ESTALE);
2052 [ # # ]: 0 : if (IS_ERR(inode))
2053 : : return ERR_CAST(inode);
2054 : :
2055 : 0 : res = d_find_any_alias(inode);
2056 [ # # ]: 0 : if (res)
2057 : 0 : goto out_iput;
2058 : :
2059 : 0 : tmp = d_alloc_anon(inode->i_sb);
2060 [ # # ]: 0 : if (!tmp) {
2061 : 0 : res = ERR_PTR(-ENOMEM);
2062 : 0 : goto out_iput;
2063 : : }
2064 : :
2065 : 0 : return __d_instantiate_anon(tmp, inode, disconnected);
2066 : :
2067 : 0 : out_iput:
2068 : 0 : iput(inode);
2069 : 0 : return res;
2070 : : }
2071 : :
2072 : : /**
2073 : : * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
2074 : : * @inode: inode to allocate the dentry for
2075 : : *
2076 : : * Obtain a dentry for an inode resulting from NFS filehandle conversion or
2077 : : * similar open by handle operations. The returned dentry may be anonymous,
2078 : : * or may have a full name (if the inode was already in the cache).
2079 : : *
2080 : : * When called on a directory inode, we must ensure that the inode only ever
2081 : : * has one dentry. If a dentry is found, that is returned instead of
2082 : : * allocating a new one.
2083 : : *
2084 : : * On successful return, the reference to the inode has been transferred
2085 : : * to the dentry. In case of an error the reference on the inode is released.
2086 : : * To make it easier to use in export operations a %NULL or IS_ERR inode may
2087 : : * be passed in and the error will be propagated to the return value,
2088 : : * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
2089 : : */
2090 : 0 : struct dentry *d_obtain_alias(struct inode *inode)
2091 : : {
2092 : 0 : return __d_obtain_alias(inode, true);
2093 : : }
2094 : : EXPORT_SYMBOL(d_obtain_alias);
2095 : :
2096 : : /**
2097 : : * d_obtain_root - find or allocate a dentry for a given inode
2098 : : * @inode: inode to allocate the dentry for
2099 : : *
2100 : : * Obtain an IS_ROOT dentry for the root of a filesystem.
2101 : : *
2102 : : * We must ensure that directory inodes only ever have one dentry. If a
2103 : : * dentry is found, that is returned instead of allocating a new one.
2104 : : *
2105 : : * On successful return, the reference to the inode has been transferred
2106 : : * to the dentry. In case of an error the reference on the inode is
2107 : : * released. A %NULL or IS_ERR inode may be passed in and will be the
2108 : : * error will be propagate to the return value, with a %NULL @inode
2109 : : * replaced by ERR_PTR(-ESTALE).
2110 : : */
2111 : 0 : struct dentry *d_obtain_root(struct inode *inode)
2112 : : {
2113 : 0 : return __d_obtain_alias(inode, false);
2114 : : }
2115 : : EXPORT_SYMBOL(d_obtain_root);
2116 : :
2117 : : /**
2118 : : * d_add_ci - lookup or allocate new dentry with case-exact name
2119 : : * @inode: the inode case-insensitive lookup has found
2120 : : * @dentry: the negative dentry that was passed to the parent's lookup func
2121 : : * @name: the case-exact name to be associated with the returned dentry
2122 : : *
2123 : : * This is to avoid filling the dcache with case-insensitive names to the
2124 : : * same inode, only the actual correct case is stored in the dcache for
2125 : : * case-insensitive filesystems.
2126 : : *
2127 : : * For a case-insensitive lookup match and if the the case-exact dentry
2128 : : * already exists in in the dcache, use it and return it.
2129 : : *
2130 : : * If no entry exists with the exact case name, allocate new dentry with
2131 : : * the exact case, and return the spliced entry.
2132 : : */
2133 : 0 : struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
2134 : : struct qstr *name)
2135 : : {
2136 : 0 : struct dentry *found, *res;
2137 : :
2138 : : /*
2139 : : * First check if a dentry matching the name already exists,
2140 : : * if not go ahead and create it now.
2141 : : */
2142 : 0 : found = d_hash_and_lookup(dentry->d_parent, name);
2143 [ # # ]: 0 : if (found) {
2144 : 0 : iput(inode);
2145 : 0 : return found;
2146 : : }
2147 [ # # ]: 0 : if (d_in_lookup(dentry)) {
2148 : 0 : found = d_alloc_parallel(dentry->d_parent, name,
2149 : : dentry->d_wait);
2150 [ # # # # ]: 0 : if (IS_ERR(found) || !d_in_lookup(found)) {
2151 : 0 : iput(inode);
2152 : 0 : return found;
2153 : : }
2154 : : } else {
2155 : 0 : found = d_alloc(dentry->d_parent, name);
2156 [ # # ]: 0 : if (!found) {
2157 : 0 : iput(inode);
2158 : 0 : return ERR_PTR(-ENOMEM);
2159 : : }
2160 : : }
2161 : 0 : res = d_splice_alias(inode, found);
2162 [ # # ]: 0 : if (res) {
2163 : 0 : dput(found);
2164 : 0 : return res;
2165 : : }
2166 : : return found;
2167 : : }
2168 : : EXPORT_SYMBOL(d_add_ci);
2169 : :
2170 : :
2171 : : static inline bool d_same_name(const struct dentry *dentry,
2172 : : const struct dentry *parent,
2173 : : const struct qstr *name)
2174 : : {
2175 : : if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
2176 : : if (dentry->d_name.len != name->len)
2177 : : return false;
2178 : : return dentry_cmp(dentry, name->name, name->len) == 0;
2179 : : }
2180 : : return parent->d_op->d_compare(dentry,
2181 : : dentry->d_name.len, dentry->d_name.name,
2182 : : name) == 0;
2183 : : }
2184 : :
2185 : : /**
2186 : : * __d_lookup_rcu - search for a dentry (racy, store-free)
2187 : : * @parent: parent dentry
2188 : : * @name: qstr of name we wish to find
2189 : : * @seqp: returns d_seq value at the point where the dentry was found
2190 : : * Returns: dentry, or NULL
2191 : : *
2192 : : * __d_lookup_rcu is the dcache lookup function for rcu-walk name
2193 : : * resolution (store-free path walking) design described in
2194 : : * Documentation/filesystems/path-lookup.txt.
2195 : : *
2196 : : * This is not to be used outside core vfs.
2197 : : *
2198 : : * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock
2199 : : * held, and rcu_read_lock held. The returned dentry must not be stored into
2200 : : * without taking d_lock and checking d_seq sequence count against @seq
2201 : : * returned here.
2202 : : *
2203 : : * A refcount may be taken on the found dentry with the d_rcu_to_refcount
2204 : : * function.
2205 : : *
2206 : : * Alternatively, __d_lookup_rcu may be called again to look up the child of
2207 : : * the returned dentry, so long as its parent's seqlock is checked after the
2208 : : * child is looked up. Thus, an interlocking stepping of sequence lock checks
2209 : : * is formed, giving integrity down the path walk.
2210 : : *
2211 : : * NOTE! The caller *has* to check the resulting dentry against the sequence
2212 : : * number we've returned before using any of the resulting dentry state!
2213 : : */
2214 : 14156881 : struct dentry *__d_lookup_rcu(const struct dentry *parent,
2215 : : const struct qstr *name,
2216 : : unsigned *seqp)
2217 : : {
2218 : 14156881 : u64 hashlen = name->hash_len;
2219 : 14156881 : const unsigned char *str = name->name;
2220 : 14156881 : struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
2221 : 14156881 : struct hlist_bl_node *node;
2222 : 14156881 : struct dentry *dentry;
2223 : :
2224 : : /*
2225 : : * Note: There is significant duplication with __d_lookup_rcu which is
2226 : : * required to prevent single threaded performance regressions
2227 : : * especially on architectures where smp_rmb (in seqcounts) are costly.
2228 : : * Keep the two functions in sync.
2229 : : */
2230 : :
2231 : : /*
2232 : : * The hash list is protected using RCU.
2233 : : *
2234 : : * Carefully use d_seq when comparing a candidate dentry, to avoid
2235 : : * races with d_move().
2236 : : *
2237 : : * It is possible that concurrent renames can mess up our list
2238 : : * walk here and result in missing our dentry, resulting in the
2239 : : * false-negative result. d_lookup() protects against concurrent
2240 : : * renames using rename_lock seqlock.
2241 : : *
2242 : : * See Documentation/filesystems/path-lookup.txt for more details.
2243 : : */
2244 [ + + ]: 14755377 : hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
2245 : 12017444 : unsigned seq;
2246 : :
2247 : 12017444 : seqretry:
2248 : : /*
2249 : : * The dentry sequence count protects us from concurrent
2250 : : * renames, and thus protects parent and name fields.
2251 : : *
2252 : : * The caller must perform a seqcount check in order
2253 : : * to do anything useful with the returned dentry.
2254 : : *
2255 : : * NOTE! We do a "raw" seqcount_begin here. That means that
2256 : : * we don't wait for the sequence count to stabilize if it
2257 : : * is in the middle of a sequence change. If we do the slow
2258 : : * dentry compare, we will do seqretries until it is stable,
2259 : : * and if we end up with a successful lookup, we actually
2260 : : * want to exit RCU lookup anyway.
2261 : : *
2262 : : * Note that raw_seqcount_begin still *does* smp_rmb(), so
2263 : : * we are still guaranteed NUL-termination of ->d_name.name.
2264 : : */
2265 : 12017444 : seq = raw_seqcount_begin(&dentry->d_seq);
2266 [ + + ]: 12017444 : if (dentry->d_parent != parent)
2267 : 598175 : continue;
2268 [ - + ]: 11419269 : if (d_unhashed(dentry))
2269 : 0 : continue;
2270 : :
2271 [ + + ]: 11419269 : if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
2272 : 546 : int tlen;
2273 : 546 : const char *tname;
2274 [ - + ]: 546 : if (dentry->d_name.hash != hashlen_hash(hashlen))
2275 : 0 : continue;
2276 : 546 : tlen = dentry->d_name.len;
2277 : 546 : tname = dentry->d_name.name;
2278 : : /* we want a consistent (name,len) pair */
2279 [ - + ]: 546 : if (read_seqcount_retry(&dentry->d_seq, seq)) {
2280 : 0 : cpu_relax();
2281 : 0 : goto seqretry;
2282 : : }
2283 [ - + ]: 546 : if (parent->d_op->d_compare(dentry,
2284 : : tlen, tname, name) != 0)
2285 : 0 : continue;
2286 : : } else {
2287 [ + + ]: 11418723 : if (dentry->d_name.hash_len != hashlen)
2288 : 321 : continue;
2289 [ - + ]: 11418402 : if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
2290 : 0 : continue;
2291 : : }
2292 : 11418948 : *seqp = seq;
2293 : 11418948 : return dentry;
2294 : : }
2295 : : return NULL;
2296 : : }
2297 : :
2298 : : /**
2299 : : * d_lookup - search for a dentry
2300 : : * @parent: parent dentry
2301 : : * @name: qstr of name we wish to find
2302 : : * Returns: dentry, or NULL
2303 : : *
2304 : : * d_lookup searches the children of the parent dentry for the name in
2305 : : * question. If the dentry is found its reference count is incremented and the
2306 : : * dentry is returned. The caller must use dput to free the entry when it has
2307 : : * finished using it. %NULL is returned if the dentry does not exist.
2308 : : */
2309 : 1945073 : struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name)
2310 : : {
2311 : 1945073 : struct dentry *dentry;
2312 : 1945073 : unsigned seq;
2313 : :
2314 : 1945073 : do {
2315 : 1945073 : seq = read_seqbegin(&rename_lock);
2316 : 1945073 : dentry = __d_lookup(parent, name);
2317 [ + + ]: 1945073 : if (dentry)
2318 : : break;
2319 [ - + ]: 1655518 : } while (read_seqretry(&rename_lock, seq));
2320 : 1945073 : return dentry;
2321 : : }
2322 : : EXPORT_SYMBOL(d_lookup);
2323 : :
2324 : : /**
2325 : : * __d_lookup - search for a dentry (racy)
2326 : : * @parent: parent dentry
2327 : : * @name: qstr of name we wish to find
2328 : : * Returns: dentry, or NULL
2329 : : *
2330 : : * __d_lookup is like d_lookup, however it may (rarely) return a
2331 : : * false-negative result due to unrelated rename activity.
2332 : : *
2333 : : * __d_lookup is slightly faster by avoiding rename_lock read seqlock,
2334 : : * however it must be used carefully, eg. with a following d_lookup in
2335 : : * the case of failure.
2336 : : *
2337 : : * __d_lookup callers must be commented.
2338 : : */
2339 : 5472788 : struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
2340 : : {
2341 : 5472788 : unsigned int hash = name->hash;
2342 : 5472788 : struct hlist_bl_head *b = d_hash(hash);
2343 : 5472788 : struct hlist_bl_node *node;
2344 : 5472788 : struct dentry *found = NULL;
2345 : 5472788 : struct dentry *dentry;
2346 : :
2347 : : /*
2348 : : * Note: There is significant duplication with __d_lookup_rcu which is
2349 : : * required to prevent single threaded performance regressions
2350 : : * especially on architectures where smp_rmb (in seqcounts) are costly.
2351 : : * Keep the two functions in sync.
2352 : : */
2353 : :
2354 : : /*
2355 : : * The hash list is protected using RCU.
2356 : : *
2357 : : * Take d_lock when comparing a candidate dentry, to avoid races
2358 : : * with d_move().
2359 : : *
2360 : : * It is possible that concurrent renames can mess up our list
2361 : : * walk here and result in missing our dentry, resulting in the
2362 : : * false-negative result. d_lookup() protects against concurrent
2363 : : * renames using rename_lock seqlock.
2364 : : *
2365 : : * See Documentation/filesystems/path-lookup.txt for more details.
2366 : : */
2367 : 5472788 : rcu_read_lock();
2368 : :
2369 [ + + ]: 5914617 : hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
2370 : :
2371 [ + + ]: 3790479 : if (dentry->d_name.hash != hash)
2372 : 441829 : continue;
2373 : :
2374 : 3348650 : spin_lock(&dentry->d_lock);
2375 [ - + ]: 3348650 : if (dentry->d_parent != parent)
2376 : 0 : goto next;
2377 [ - + ]: 3348650 : if (d_unhashed(dentry))
2378 : 0 : goto next;
2379 : :
2380 [ - + ]: 3348650 : if (!d_same_name(dentry, parent, name))
2381 : 0 : goto next;
2382 : :
2383 : 3348650 : dentry->d_lockref.count++;
2384 : 3348650 : found = dentry;
2385 : 3348650 : spin_unlock(&dentry->d_lock);
2386 : : break;
2387 : 0 : next:
2388 : 0 : spin_unlock(&dentry->d_lock);
2389 : : }
2390 : 5472788 : rcu_read_unlock();
2391 : :
2392 : 5472788 : return found;
2393 : : }
2394 : :
2395 : : /**
2396 : : * d_hash_and_lookup - hash the qstr then search for a dentry
2397 : : * @dir: Directory to search in
2398 : : * @name: qstr of name we wish to find
2399 : : *
2400 : : * On lookup failure NULL is returned; on bad name - ERR_PTR(-error)
2401 : : */
2402 : 185216 : struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
2403 : : {
2404 : : /*
2405 : : * Check for a fs-specific hash function. Note that we must
2406 : : * calculate the standard hash first, as the d_op->d_hash()
2407 : : * routine may choose to leave the hash value unchanged.
2408 : : */
2409 : 185216 : name->hash = full_name_hash(dir, name->name, name->len);
2410 [ - + ]: 185216 : if (dir->d_flags & DCACHE_OP_HASH) {
2411 : 0 : int err = dir->d_op->d_hash(dir, name);
2412 [ # # ]: 0 : if (unlikely(err < 0))
2413 : 0 : return ERR_PTR(err);
2414 : : }
2415 : 185216 : return d_lookup(dir, name);
2416 : : }
2417 : : EXPORT_SYMBOL(d_hash_and_lookup);
2418 : :
2419 : : /*
2420 : : * When a file is deleted, we have two options:
2421 : : * - turn this dentry into a negative dentry
2422 : : * - unhash this dentry and free it.
2423 : : *
2424 : : * Usually, we want to just turn this into
2425 : : * a negative dentry, but if anybody else is
2426 : : * currently using the dentry or the inode
2427 : : * we can't do that and we fall back on removing
2428 : : * it from the hash queues and waiting for
2429 : : * it to be deleted later when it has no users
2430 : : */
2431 : :
2432 : : /**
2433 : : * d_delete - delete a dentry
2434 : : * @dentry: The dentry to delete
2435 : : *
2436 : : * Turn the dentry into a negative dentry if possible, otherwise
2437 : : * remove it from the hash queues so it can be deleted later
2438 : : */
2439 : :
2440 : 9800 : void d_delete(struct dentry * dentry)
2441 : : {
2442 : 9800 : struct inode *inode = dentry->d_inode;
2443 : :
2444 : 9800 : spin_lock(&inode->i_lock);
2445 : 9800 : spin_lock(&dentry->d_lock);
2446 : : /*
2447 : : * Are we the only user?
2448 : : */
2449 [ + - ]: 9800 : if (dentry->d_lockref.count == 1) {
2450 : 9800 : dentry->d_flags &= ~DCACHE_CANT_MOUNT;
2451 : 9800 : dentry_unlink_inode(dentry);
2452 : : } else {
2453 [ # # ]: 0 : __d_drop(dentry);
2454 : 0 : spin_unlock(&dentry->d_lock);
2455 : 0 : spin_unlock(&inode->i_lock);
2456 : : }
2457 : 9800 : }
2458 : : EXPORT_SYMBOL(d_delete);
2459 : :
2460 : 2081530 : static void __d_rehash(struct dentry *entry)
2461 : : {
2462 : 2081530 : struct hlist_bl_head *b = d_hash(entry->d_name.hash);
2463 : :
2464 : 2081530 : hlist_bl_lock(b);
2465 [ + + ]: 2081530 : hlist_bl_add_head_rcu(&entry->d_hash, b);
2466 : 2081530 : hlist_bl_unlock(b);
2467 : 2081530 : }
2468 : :
2469 : : /**
2470 : : * d_rehash - add an entry back to the hash
2471 : : * @entry: dentry to add to the hash
2472 : : *
2473 : : * Adds a dentry to the hash according to its name.
2474 : : */
2475 : :
2476 : 0 : void d_rehash(struct dentry * entry)
2477 : : {
2478 : 0 : spin_lock(&entry->d_lock);
2479 : 0 : __d_rehash(entry);
2480 : 0 : spin_unlock(&entry->d_lock);
2481 : 0 : }
2482 : : EXPORT_SYMBOL(d_rehash);
2483 : :
2484 : 1967911 : static inline unsigned start_dir_add(struct inode *dir)
2485 : : {
2486 : :
2487 : 1967911 : for (;;) {
2488 : 1967911 : unsigned n = dir->i_dir_seq;
2489 [ + - + - ]: 1967911 : if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
2490 : 1967911 : return n;
2491 : 0 : cpu_relax();
2492 : : }
2493 : : }
2494 : :
2495 : 1967911 : static inline void end_dir_add(struct inode *dir, unsigned n)
2496 : : {
2497 : 1967911 : smp_store_release(&dir->i_dir_seq, n + 2);
2498 : 1967911 : }
2499 : :
2500 : 415 : static void d_wait_lookup(struct dentry *dentry)
2501 : : {
2502 [ + - ]: 415 : if (d_in_lookup(dentry)) {
2503 : 415 : DECLARE_WAITQUEUE(wait, current);
2504 : 415 : add_wait_queue(dentry->d_wait, &wait);
2505 : 415 : do {
2506 : 415 : set_current_state(TASK_UNINTERRUPTIBLE);
2507 : 415 : spin_unlock(&dentry->d_lock);
2508 : 415 : schedule();
2509 : 415 : spin_lock(&dentry->d_lock);
2510 [ - + ]: 415 : } while (d_in_lookup(dentry));
2511 : : }
2512 : 415 : }
2513 : :
2514 : 2203781 : struct dentry *d_alloc_parallel(struct dentry *parent,
2515 : : const struct qstr *name,
2516 : : wait_queue_head_t *wq)
2517 : : {
2518 : 2203781 : unsigned int hash = name->hash;
2519 : 2203781 : struct hlist_bl_head *b = in_lookup_hash(parent, hash);
2520 : 2203781 : struct hlist_bl_node *node;
2521 : 2203781 : struct dentry *new = d_alloc(parent, name);
2522 : 2203781 : struct dentry *dentry;
2523 : 2203781 : unsigned seq, r_seq, d_seq;
2524 : :
2525 [ + - ]: 2203781 : if (unlikely(!new))
2526 : : return ERR_PTR(-ENOMEM);
2527 : :
2528 : 2203781 : retry:
2529 : 2203784 : rcu_read_lock();
2530 : 2203784 : seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
2531 : 2203784 : r_seq = read_seqbegin(&rename_lock);
2532 : 2203784 : dentry = __d_lookup_rcu(parent, name, &d_seq);
2533 [ + + ]: 2203784 : if (unlikely(dentry)) {
2534 [ - + ]: 2 : if (!lockref_get_not_dead(&dentry->d_lockref)) {
2535 : 0 : rcu_read_unlock();
2536 : 0 : goto retry;
2537 : : }
2538 [ - + ]: 2 : if (read_seqcount_retry(&dentry->d_seq, d_seq)) {
2539 : 0 : rcu_read_unlock();
2540 : 0 : dput(dentry);
2541 : 0 : goto retry;
2542 : : }
2543 : 2 : rcu_read_unlock();
2544 : 2 : dput(new);
2545 : 2 : return dentry;
2546 : : }
2547 [ - + ]: 2203782 : if (unlikely(read_seqretry(&rename_lock, r_seq))) {
2548 : 0 : rcu_read_unlock();
2549 : 0 : goto retry;
2550 : : }
2551 : :
2552 [ - + ]: 2203782 : if (unlikely(seq & 1)) {
2553 : 0 : rcu_read_unlock();
2554 : 0 : goto retry;
2555 : : }
2556 : :
2557 : 2203782 : hlist_bl_lock(b);
2558 [ - + ]: 2203782 : if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
2559 : 0 : hlist_bl_unlock(b);
2560 : 0 : rcu_read_unlock();
2561 : 0 : goto retry;
2562 : : }
2563 : : /*
2564 : : * No changes for the parent since the beginning of d_lookup().
2565 : : * Since all removals from the chain happen with hlist_bl_lock(),
2566 : : * any potential in-lookup matches are going to stay here until
2567 : : * we unlock the chain. All fields are stable in everything
2568 : : * we encounter.
2569 : : */
2570 [ + + ]: 2203838 : hlist_bl_for_each_entry(dentry, node, b, d_u.d_in_lookup_hash) {
2571 [ + + ]: 471 : if (dentry->d_name.hash != hash)
2572 : 56 : continue;
2573 [ - + ]: 415 : if (dentry->d_parent != parent)
2574 : 0 : continue;
2575 [ - + ]: 415 : if (!d_same_name(dentry, parent, name))
2576 : 0 : continue;
2577 : 415 : hlist_bl_unlock(b);
2578 : : /* now we can try to grab a reference */
2579 [ - + ]: 415 : if (!lockref_get_not_dead(&dentry->d_lockref)) {
2580 : 0 : rcu_read_unlock();
2581 : 0 : goto retry;
2582 : : }
2583 : :
2584 : 415 : rcu_read_unlock();
2585 : : /*
2586 : : * somebody is likely to be still doing lookup for it;
2587 : : * wait for them to finish
2588 : : */
2589 : 415 : spin_lock(&dentry->d_lock);
2590 : 415 : d_wait_lookup(dentry);
2591 : : /*
2592 : : * it's not in-lookup anymore; in principle we should repeat
2593 : : * everything from dcache lookup, but it's likely to be what
2594 : : * d_lookup() would've found anyway. If it is, just return it;
2595 : : * otherwise we really have to repeat the whole thing.
2596 : : */
2597 [ - + ]: 415 : if (unlikely(dentry->d_name.hash != hash))
2598 : 0 : goto mismatch;
2599 [ - + ]: 415 : if (unlikely(dentry->d_parent != parent))
2600 : 0 : goto mismatch;
2601 [ + + ]: 415 : if (unlikely(d_unhashed(dentry)))
2602 : 3 : goto mismatch;
2603 [ - + ]: 412 : if (unlikely(!d_same_name(dentry, parent, name)))
2604 : 0 : goto mismatch;
2605 : : /* OK, it *is* a hashed match; return it */
2606 : 412 : spin_unlock(&dentry->d_lock);
2607 : 412 : dput(new);
2608 : 412 : return dentry;
2609 : : }
2610 : 2203367 : rcu_read_unlock();
2611 : : /* we can't take ->d_lock here; it's OK, though. */
2612 : 2203367 : new->d_flags |= DCACHE_PAR_LOOKUP;
2613 : 2203367 : new->d_wait = wq;
2614 [ + + ]: 2203367 : hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b);
2615 : 2203367 : hlist_bl_unlock(b);
2616 : 2203367 : return new;
2617 : 3 : mismatch:
2618 : 3 : spin_unlock(&dentry->d_lock);
2619 : 3 : dput(dentry);
2620 : 3 : goto retry;
2621 : : }
2622 : : EXPORT_SYMBOL(d_alloc_parallel);
2623 : :
2624 : 2203367 : void __d_lookup_done(struct dentry *dentry)
2625 : : {
2626 : 2203367 : struct hlist_bl_head *b = in_lookup_hash(dentry->d_parent,
2627 : : dentry->d_name.hash);
2628 : 2203367 : hlist_bl_lock(b);
2629 : 2203367 : dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
2630 [ + + ]: 2203367 : __hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
2631 : 2203367 : wake_up_all(dentry->d_wait);
2632 : 2203367 : dentry->d_wait = NULL;
2633 : 2203367 : hlist_bl_unlock(b);
2634 : 2203367 : INIT_HLIST_NODE(&dentry->d_u.d_alias);
2635 : 2203367 : INIT_LIST_HEAD(&dentry->d_lru);
2636 : 2203367 : }
2637 : : EXPORT_SYMBOL(__d_lookup_done);
2638 : :
2639 : : /* inode->i_lock held if inode is non-NULL */
2640 : :
2641 : 2063290 : static inline void __d_add(struct dentry *dentry, struct inode *inode)
2642 : : {
2643 : 2063290 : struct inode *dir = NULL;
2644 : 2063290 : unsigned n;
2645 : 2063290 : spin_lock(&dentry->d_lock);
2646 [ + + ]: 2063290 : if (unlikely(d_in_lookup(dentry))) {
2647 : 1967911 : dir = dentry->d_parent->d_inode;
2648 : 1967911 : n = start_dir_add(dir);
2649 : 1967911 : __d_lookup_done(dentry);
2650 : : }
2651 [ + + ]: 2063290 : if (inode) {
2652 : 392253 : unsigned add_flags = d_flags_for_inode(inode);
2653 [ - + ]: 392253 : hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
2654 : 392253 : raw_write_seqcount_begin(&dentry->d_seq);
2655 : 392253 : __d_set_inode_and_type(dentry, inode, add_flags);
2656 : 392253 : raw_write_seqcount_end(&dentry->d_seq);
2657 : 392253 : fsnotify_update_flags(dentry);
2658 : : }
2659 : 2063290 : __d_rehash(dentry);
2660 [ + + ]: 2063290 : if (dir)
2661 : 1967911 : end_dir_add(dir, n);
2662 : 2063290 : spin_unlock(&dentry->d_lock);
2663 [ + + ]: 2063290 : if (inode)
2664 : 392253 : spin_unlock(&inode->i_lock);
2665 : 2063290 : }
2666 : :
2667 : : /**
2668 : : * d_add - add dentry to hash queues
2669 : : * @entry: dentry to add
2670 : : * @inode: The inode to attach to this dentry
2671 : : *
2672 : : * This adds the entry to the hash queues and initializes @inode.
2673 : : * The entry was actually filled in earlier during d_alloc().
2674 : : */
2675 : :
2676 : 1575726 : void d_add(struct dentry *entry, struct inode *inode)
2677 : : {
2678 [ + + ]: 1575726 : if (inode) {
2679 : 5226 : security_d_instantiate(entry, inode);
2680 : 5226 : spin_lock(&inode->i_lock);
2681 : : }
2682 : 1575726 : __d_add(entry, inode);
2683 : 1575726 : }
2684 : : EXPORT_SYMBOL(d_add);
2685 : :
2686 : : /**
2687 : : * d_exact_alias - find and hash an exact unhashed alias
2688 : : * @entry: dentry to add
2689 : : * @inode: The inode to go with this dentry
2690 : : *
2691 : : * If an unhashed dentry with the same name/parent and desired
2692 : : * inode already exists, hash and return it. Otherwise, return
2693 : : * NULL.
2694 : : *
2695 : : * Parent directory should be locked.
2696 : : */
2697 : 0 : struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
2698 : : {
2699 : 0 : struct dentry *alias;
2700 : 0 : unsigned int hash = entry->d_name.hash;
2701 : :
2702 : 0 : spin_lock(&inode->i_lock);
2703 [ # # # # : 0 : hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
# # ]
2704 : : /*
2705 : : * Don't need alias->d_lock here, because aliases with
2706 : : * d_parent == entry->d_parent are not subject to name or
2707 : : * parent changes, because the parent inode i_mutex is held.
2708 : : */
2709 [ # # ]: 0 : if (alias->d_name.hash != hash)
2710 : 0 : continue;
2711 [ # # ]: 0 : if (alias->d_parent != entry->d_parent)
2712 : 0 : continue;
2713 [ # # ]: 0 : if (!d_same_name(alias, entry->d_parent, &entry->d_name))
2714 : 0 : continue;
2715 : 0 : spin_lock(&alias->d_lock);
2716 [ # # ]: 0 : if (!d_unhashed(alias)) {
2717 : 0 : spin_unlock(&alias->d_lock);
2718 : 0 : alias = NULL;
2719 : : } else {
2720 : 0 : __dget_dlock(alias);
2721 : 0 : __d_rehash(alias);
2722 : 0 : spin_unlock(&alias->d_lock);
2723 : : }
2724 : 0 : spin_unlock(&inode->i_lock);
2725 : 0 : return alias;
2726 : : }
2727 : 0 : spin_unlock(&inode->i_lock);
2728 : 0 : return NULL;
2729 : : }
2730 : : EXPORT_SYMBOL(d_exact_alias);
2731 : :
2732 : 0 : static void swap_names(struct dentry *dentry, struct dentry *target)
2733 : : {
2734 [ # # ]: 0 : if (unlikely(dname_external(target))) {
2735 [ # # ]: 0 : if (unlikely(dname_external(dentry))) {
2736 : : /*
2737 : : * Both external: swap the pointers
2738 : : */
2739 : 0 : swap(target->d_name.name, dentry->d_name.name);
2740 : : } else {
2741 : : /*
2742 : : * dentry:internal, target:external. Steal target's
2743 : : * storage and make target internal.
2744 : : */
2745 : 0 : memcpy(target->d_iname, dentry->d_name.name,
2746 : 0 : dentry->d_name.len + 1);
2747 : 0 : dentry->d_name.name = target->d_name.name;
2748 : 0 : target->d_name.name = target->d_iname;
2749 : : }
2750 : : } else {
2751 [ # # ]: 0 : if (unlikely(dname_external(dentry))) {
2752 : : /*
2753 : : * dentry:external, target:internal. Give dentry's
2754 : : * storage to target and make dentry internal
2755 : : */
2756 : 0 : memcpy(dentry->d_iname, target->d_name.name,
2757 : 0 : target->d_name.len + 1);
2758 : 0 : target->d_name.name = dentry->d_name.name;
2759 : 0 : dentry->d_name.name = dentry->d_iname;
2760 : : } else {
2761 : : /*
2762 : : * Both are internal.
2763 : : */
2764 : : unsigned int i;
2765 : : BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
2766 [ # # ]: 0 : for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
2767 : 0 : swap(((long *) &dentry->d_iname)[i],
2768 : : ((long *) &target->d_iname)[i]);
2769 : : }
2770 : : }
2771 : : }
2772 : 0 : swap(dentry->d_name.hash_len, target->d_name.hash_len);
2773 : 0 : }
2774 : :
2775 : 18240 : static void copy_name(struct dentry *dentry, struct dentry *target)
2776 : : {
2777 : 18240 : struct external_name *old_name = NULL;
2778 [ + + ]: 18240 : if (unlikely(dname_external(dentry)))
2779 : 2053 : old_name = external_name(dentry);
2780 [ + + ]: 18240 : if (unlikely(dname_external(target))) {
2781 : 1326 : atomic_inc(&external_name(target)->u.count);
2782 : 1326 : dentry->d_name = target->d_name;
2783 : : } else {
2784 : 16914 : memcpy(dentry->d_iname, target->d_name.name,
2785 : 16914 : target->d_name.len + 1);
2786 : 16914 : dentry->d_name.name = dentry->d_iname;
2787 : 16914 : dentry->d_name.hash_len = target->d_name.hash_len;
2788 : : }
2789 [ + + - + ]: 18240 : if (old_name && likely(atomic_dec_and_test(&old_name->u.count)))
2790 : 0 : kfree_rcu(old_name, u.head);
2791 : 18240 : }
2792 : :
2793 : : /*
2794 : : * __d_move - move a dentry
2795 : : * @dentry: entry to move
2796 : : * @target: new dentry
2797 : : * @exchange: exchange the two dentries
2798 : : *
2799 : : * Update the dcache to reflect the move of a file name. Negative
2800 : : * dcache entries should not be moved in this way. Caller must hold
2801 : : * rename_lock, the i_mutex of the source and target directories,
2802 : : * and the sb->s_vfs_rename_mutex if they differ. See lock_rename().
2803 : : */
2804 : 18240 : static void __d_move(struct dentry *dentry, struct dentry *target,
2805 : : bool exchange)
2806 : : {
2807 : 18240 : struct dentry *old_parent, *p;
2808 : 18240 : struct inode *dir = NULL;
2809 : 18240 : unsigned n;
2810 : :
2811 [ - + ]: 18240 : WARN_ON(!dentry->d_inode);
2812 [ - + + - ]: 18240 : if (WARN_ON(dentry == target))
2813 : : return;
2814 : :
2815 [ - + ]: 18240 : BUG_ON(d_ancestor(target, dentry));
2816 : 18240 : old_parent = dentry->d_parent;
2817 : 18240 : p = d_ancestor(old_parent, target);
2818 [ - + ]: 18240 : if (IS_ROOT(dentry)) {
2819 [ # # ]: 0 : BUG_ON(p);
2820 : 0 : spin_lock(&target->d_parent->d_lock);
2821 [ - + ]: 18240 : } else if (!p) {
2822 : : /* target is not a descendent of dentry->d_parent */
2823 : 0 : spin_lock(&target->d_parent->d_lock);
2824 : 0 : spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED);
2825 : : } else {
2826 [ - + ]: 18240 : BUG_ON(p == dentry);
2827 : 18240 : spin_lock(&old_parent->d_lock);
2828 [ - + ]: 18240 : if (p != target)
2829 : 0 : spin_lock_nested(&target->d_parent->d_lock,
2830 : : DENTRY_D_LOCK_NESTED);
2831 : : }
2832 : 18240 : spin_lock_nested(&dentry->d_lock, 2);
2833 : 18240 : spin_lock_nested(&target->d_lock, 3);
2834 : :
2835 [ - + ]: 18240 : if (unlikely(d_in_lookup(target))) {
2836 : 0 : dir = target->d_parent->d_inode;
2837 : 0 : n = start_dir_add(dir);
2838 : 0 : __d_lookup_done(target);
2839 : : }
2840 : :
2841 : 18240 : write_seqcount_begin(&dentry->d_seq);
2842 : 18240 : write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
2843 : :
2844 : : /* unhash both */
2845 [ + - ]: 18240 : if (!d_unhashed(dentry))
2846 : 18240 : ___d_drop(dentry);
2847 [ + - ]: 18240 : if (!d_unhashed(target))
2848 : 18240 : ___d_drop(target);
2849 : :
2850 : : /* ... and switch them in the tree */
2851 : 18240 : dentry->d_parent = target->d_parent;
2852 [ + - ]: 18240 : if (!exchange) {
2853 : 18240 : copy_name(dentry, target);
2854 : 18240 : target->d_hash.pprev = NULL;
2855 : 18240 : dentry->d_parent->d_lockref.count++;
2856 [ + - ]: 18240 : if (dentry != old_parent) /* wasn't IS_ROOT */
2857 [ - + ]: 18240 : WARN_ON(!--old_parent->d_lockref.count);
2858 : : } else {
2859 : 0 : target->d_parent = old_parent;
2860 : 0 : swap_names(dentry, target);
2861 : 0 : list_move(&target->d_child, &target->d_parent->d_subdirs);
2862 : 0 : __d_rehash(target);
2863 : 0 : fsnotify_update_flags(target);
2864 : : }
2865 : 18240 : list_move(&dentry->d_child, &dentry->d_parent->d_subdirs);
2866 : 18240 : __d_rehash(dentry);
2867 : 18240 : fsnotify_update_flags(dentry);
2868 : 18240 : fscrypt_handle_d_move(dentry);
2869 : :
2870 : 18240 : write_seqcount_end(&target->d_seq);
2871 : 18240 : write_seqcount_end(&dentry->d_seq);
2872 : :
2873 [ - + ]: 18240 : if (dir)
2874 : 0 : end_dir_add(dir, n);
2875 : :
2876 [ - + ]: 18240 : if (dentry->d_parent != old_parent)
2877 : 0 : spin_unlock(&dentry->d_parent->d_lock);
2878 [ + - ]: 18240 : if (dentry != old_parent)
2879 : 18240 : spin_unlock(&old_parent->d_lock);
2880 : 18240 : spin_unlock(&target->d_lock);
2881 : 18240 : spin_unlock(&dentry->d_lock);
2882 : : }
2883 : :
2884 : : /*
2885 : : * d_move - move a dentry
2886 : : * @dentry: entry to move
2887 : : * @target: new dentry
2888 : : *
2889 : : * Update the dcache to reflect the move of a file name. Negative
2890 : : * dcache entries should not be moved in this way. See the locking
2891 : : * requirements for __d_move.
2892 : : */
2893 : 18240 : void d_move(struct dentry *dentry, struct dentry *target)
2894 : : {
2895 : 18240 : write_seqlock(&rename_lock);
2896 : 18240 : __d_move(dentry, target, false);
2897 : 18240 : write_sequnlock(&rename_lock);
2898 : 18240 : }
2899 : : EXPORT_SYMBOL(d_move);
2900 : :
2901 : : /*
2902 : : * d_exchange - exchange two dentries
2903 : : * @dentry1: first dentry
2904 : : * @dentry2: second dentry
2905 : : */
2906 : 0 : void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
2907 : : {
2908 : 0 : write_seqlock(&rename_lock);
2909 : :
2910 [ # # ]: 0 : WARN_ON(!dentry1->d_inode);
2911 [ # # ]: 0 : WARN_ON(!dentry2->d_inode);
2912 [ # # ]: 0 : WARN_ON(IS_ROOT(dentry1));
2913 [ # # ]: 0 : WARN_ON(IS_ROOT(dentry2));
2914 : :
2915 : 0 : __d_move(dentry1, dentry2, true);
2916 : :
2917 : 0 : write_sequnlock(&rename_lock);
2918 : 0 : }
2919 : :
2920 : : /**
2921 : : * d_ancestor - search for an ancestor
2922 : : * @p1: ancestor dentry
2923 : : * @p2: child dentry
2924 : : *
2925 : : * Returns the ancestor dentry of p2 which is a child of p1, if p1 is
2926 : : * an ancestor of p2, else NULL.
2927 : : */
2928 : 18240 : struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
2929 : : {
2930 : 18240 : struct dentry *p;
2931 : :
2932 [ + + - - : 108750 : for (p = p2; !IS_ROOT(p); p = p->d_parent) {
- - + + +
- ]
2933 [ + + - - : 83958 : if (p->d_parent == p1)
- - + - -
+ ]
2934 : 0 : return p;
2935 : : }
2936 : : return NULL;
2937 : : }
2938 : :
2939 : : /*
2940 : : * This helper attempts to cope with remotely renamed directories
2941 : : *
2942 : : * It assumes that the caller is already holding
2943 : : * dentry->d_parent->d_inode->i_mutex, and rename_lock
2944 : : *
2945 : : * Note: If ever the locking in lock_rename() changes, then please
2946 : : * remember to update this too...
2947 : : */
2948 : : static int __d_unalias(struct inode *inode,
2949 : : struct dentry *dentry, struct dentry *alias)
2950 : : {
2951 : : struct mutex *m1 = NULL;
2952 : : struct rw_semaphore *m2 = NULL;
2953 : : int ret = -ESTALE;
2954 : :
2955 : : /* If alias and dentry share a parent, then no extra locks required */
2956 : : if (alias->d_parent == dentry->d_parent)
2957 : : goto out_unalias;
2958 : :
2959 : : /* See lock_rename() */
2960 : : if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
2961 : : goto out_err;
2962 : : m1 = &dentry->d_sb->s_vfs_rename_mutex;
2963 : : if (!inode_trylock_shared(alias->d_parent->d_inode))
2964 : : goto out_err;
2965 : : m2 = &alias->d_parent->d_inode->i_rwsem;
2966 : : out_unalias:
2967 : : __d_move(alias, dentry, false);
2968 : : ret = 0;
2969 : : out_err:
2970 : : if (m2)
2971 : : up_read(m2);
2972 : : if (m1)
2973 : : mutex_unlock(m1);
2974 : : return ret;
2975 : : }
2976 : :
2977 : : /**
2978 : : * d_splice_alias - splice a disconnected dentry into the tree if one exists
2979 : : * @inode: the inode which may have a disconnected dentry
2980 : : * @dentry: a negative dentry which we want to point to the inode.
2981 : : *
2982 : : * If inode is a directory and has an IS_ROOT alias, then d_move that in
2983 : : * place of the given dentry and return it, else simply d_add the inode
2984 : : * to the dentry and return NULL.
2985 : : *
2986 : : * If a non-IS_ROOT directory is found, the filesystem is corrupt, and
2987 : : * we should error out: directories can't have multiple aliases.
2988 : : *
2989 : : * This is needed in the lookup routine of any filesystem that is exportable
2990 : : * (via knfsd) so that we can build dcache paths to directories effectively.
2991 : : *
2992 : : * If a dentry was found and moved, then it is returned. Otherwise NULL
2993 : : * is returned. This matches the expected return value of ->lookup.
2994 : : *
2995 : : * Cluster filesystems may call this function with a negative, hashed dentry.
2996 : : * In that case, we know that the inode will be a regular file, and also this
2997 : : * will only occur during atomic_open. So we need to check for the dentry
2998 : : * being already hashed only in the final case.
2999 : : */
3000 : 487564 : struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
3001 : : {
3002 [ + - ]: 487564 : if (IS_ERR(inode))
3003 : : return ERR_CAST(inode);
3004 : :
3005 [ - + ]: 487564 : BUG_ON(!d_unhashed(dentry));
3006 : :
3007 [ + + ]: 487564 : if (!inode)
3008 : 100537 : goto out;
3009 : :
3010 : 387027 : security_d_instantiate(dentry, inode);
3011 : 387027 : spin_lock(&inode->i_lock);
3012 [ + + ]: 387027 : if (S_ISDIR(inode->i_mode)) {
3013 [ - + ]: 89690 : struct dentry *new = __d_find_any_alias(inode);
3014 [ + - ]: 89690 : if (unlikely(new)) {
3015 : : /* The reference to new ensures it remains an alias */
3016 : 0 : spin_unlock(&inode->i_lock);
3017 : 0 : write_seqlock(&rename_lock);
3018 [ # # ]: 0 : if (unlikely(d_ancestor(new, dentry))) {
3019 : 0 : write_sequnlock(&rename_lock);
3020 : 0 : dput(new);
3021 : 0 : new = ERR_PTR(-ELOOP);
3022 [ # # ]: 0 : pr_warn_ratelimited(
3023 : : "VFS: Lookup of '%s' in %s %s"
3024 : : " would have caused loop\n",
3025 : : dentry->d_name.name,
3026 : : inode->i_sb->s_type->name,
3027 : : inode->i_sb->s_id);
3028 [ # # ]: 0 : } else if (!IS_ROOT(new)) {
3029 [ # # ]: 0 : struct dentry *old_parent = dget(new->d_parent);
3030 : 0 : int err = __d_unalias(inode, dentry, new);
3031 : 0 : write_sequnlock(&rename_lock);
3032 [ # # ]: 0 : if (err) {
3033 : 0 : dput(new);
3034 : 0 : new = ERR_PTR(err);
3035 : : }
3036 : 0 : dput(old_parent);
3037 : : } else {
3038 : 0 : __d_move(new, dentry, false);
3039 : 0 : write_sequnlock(&rename_lock);
3040 : : }
3041 : 0 : iput(inode);
3042 : 0 : return new;
3043 : : }
3044 : : }
3045 : 387027 : out:
3046 : 487564 : __d_add(dentry, inode);
3047 : 487564 : return NULL;
3048 : : }
3049 : : EXPORT_SYMBOL(d_splice_alias);
3050 : :
3051 : : /*
3052 : : * Test whether new_dentry is a subdirectory of old_dentry.
3053 : : *
3054 : : * Trivially implemented using the dcache structure
3055 : : */
3056 : :
3057 : : /**
3058 : : * is_subdir - is new dentry a subdirectory of old_dentry
3059 : : * @new_dentry: new dentry
3060 : : * @old_dentry: old dentry
3061 : : *
3062 : : * Returns true if new_dentry is a subdirectory of the parent (at any depth).
3063 : : * Returns false otherwise.
3064 : : * Caller must ensure that "new_dentry" is pinned before calling is_subdir()
3065 : : */
3066 : :
3067 : 7722 : bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
3068 : : {
3069 : 7722 : bool result;
3070 : 7722 : unsigned seq;
3071 : :
3072 [ + + ]: 7722 : if (new_dentry == old_dentry)
3073 : : return true;
3074 : :
3075 : 7566 : do {
3076 : : /* for restarting inner loop in case of seq retry */
3077 : 7566 : seq = read_seqbegin(&rename_lock);
3078 : : /*
3079 : : * Need rcu_readlock to protect against the d_parent trashing
3080 : : * due to d_move
3081 : : */
3082 : 7566 : rcu_read_lock();
3083 [ + + ]: 7566 : if (d_ancestor(old_dentry, new_dentry))
3084 : : result = true;
3085 : : else
3086 : 6552 : result = false;
3087 : 7566 : rcu_read_unlock();
3088 [ - + ]: 7566 : } while (read_seqretry(&rename_lock, seq));
3089 : :
3090 : : return result;
3091 : : }
3092 : : EXPORT_SYMBOL(is_subdir);
3093 : :
3094 : 234 : static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
3095 : : {
3096 : 234 : struct dentry *root = data;
3097 [ - + ]: 234 : if (dentry != root) {
3098 [ # # # # ]: 0 : if (d_unhashed(dentry) || !dentry->d_inode)
3099 : : return D_WALK_SKIP;
3100 : :
3101 [ # # ]: 0 : if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
3102 : 0 : dentry->d_flags |= DCACHE_GENOCIDE;
3103 : 0 : dentry->d_lockref.count--;
3104 : : }
3105 : : }
3106 : : return D_WALK_CONTINUE;
3107 : : }
3108 : :
3109 : 234 : void d_genocide(struct dentry *parent)
3110 : : {
3111 : 234 : d_walk(parent, parent, d_genocide_kill);
3112 : 234 : }
3113 : :
3114 : : EXPORT_SYMBOL(d_genocide);
3115 : :
3116 : 0 : void d_tmpfile(struct dentry *dentry, struct inode *inode)
3117 : : {
3118 : 0 : inode_dec_link_count(inode);
3119 [ # # # # : 0 : BUG_ON(dentry->d_name.name != dentry->d_iname ||
# # ]
3120 : : !hlist_unhashed(&dentry->d_u.d_alias) ||
3121 : : !d_unlinked(dentry));
3122 : 0 : spin_lock(&dentry->d_parent->d_lock);
3123 : 0 : spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
3124 : 0 : dentry->d_name.len = sprintf(dentry->d_iname, "#%llu",
3125 : 0 : (unsigned long long)inode->i_ino);
3126 : 0 : spin_unlock(&dentry->d_lock);
3127 : 0 : spin_unlock(&dentry->d_parent->d_lock);
3128 : 0 : d_instantiate(dentry, inode);
3129 : 0 : }
3130 : : EXPORT_SYMBOL(d_tmpfile);
3131 : :
3132 : : static __initdata unsigned long dhash_entries;
3133 : 0 : static int __init set_dhash_entries(char *str)
3134 : : {
3135 [ # # ]: 0 : if (!str)
3136 : : return 0;
3137 : 0 : dhash_entries = simple_strtoul(str, &str, 0);
3138 : 0 : return 1;
3139 : : }
3140 : : __setup("dhash_entries=", set_dhash_entries);
3141 : :
3142 : 78 : static void __init dcache_init_early(void)
3143 : : {
3144 : : /* If hashes are distributed across NUMA nodes, defer
3145 : : * hash allocation until vmalloc space is available.
3146 : : */
3147 [ + - ]: 78 : if (hashdist)
3148 : : return;
3149 : :
3150 : 156 : dentry_hashtable =
3151 : 78 : alloc_large_system_hash("Dentry cache",
3152 : : sizeof(struct hlist_bl_head),
3153 : : dhash_entries,
3154 : : 13,
3155 : : HASH_EARLY | HASH_ZERO,
3156 : : &d_hash_shift,
3157 : : NULL,
3158 : : 0,
3159 : : 0);
3160 : 78 : d_hash_shift = 32 - d_hash_shift;
3161 : : }
3162 : :
3163 : 78 : static void __init dcache_init(void)
3164 : : {
3165 : : /*
3166 : : * A constructor could be added for stable state like the lists,
3167 : : * but it is probably not worth it because of the cache nature
3168 : : * of the dcache.
3169 : : */
3170 : 78 : dentry_cache = KMEM_CACHE_USERCOPY(dentry,
3171 : : SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
3172 : : d_iname);
3173 : :
3174 : : /* Hash may have been set up in dcache_init_early */
3175 [ - + ]: 78 : if (!hashdist)
3176 : : return;
3177 : :
3178 : 0 : dentry_hashtable =
3179 : 0 : alloc_large_system_hash("Dentry cache",
3180 : : sizeof(struct hlist_bl_head),
3181 : : dhash_entries,
3182 : : 13,
3183 : : HASH_ZERO,
3184 : : &d_hash_shift,
3185 : : NULL,
3186 : : 0,
3187 : : 0);
3188 : 0 : d_hash_shift = 32 - d_hash_shift;
3189 : : }
3190 : :
3191 : : /* SLAB cache for __getname() consumers */
3192 : : struct kmem_cache *names_cachep __read_mostly;
3193 : : EXPORT_SYMBOL(names_cachep);
3194 : :
3195 : 78 : void __init vfs_caches_init_early(void)
3196 : : {
3197 : 78 : int i;
3198 : :
3199 [ + + ]: 79950 : for (i = 0; i < ARRAY_SIZE(in_lookup_hashtable); i++)
3200 : 79872 : INIT_HLIST_BL_HEAD(&in_lookup_hashtable[i]);
3201 : :
3202 : 78 : dcache_init_early();
3203 : 78 : inode_init_early();
3204 : 78 : }
3205 : :
3206 : 78 : void __init vfs_caches_init(void)
3207 : : {
3208 : 78 : names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
3209 : : SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
3210 : :
3211 : 78 : dcache_init();
3212 : 78 : inode_init();
3213 : 78 : files_init();
3214 : 78 : files_maxfiles_init();
3215 : 78 : mnt_init();
3216 : 78 : bdev_cache_init();
3217 : 78 : chrdev_init();
3218 : 78 : }
|
