Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/dcache.c | |
3 | * | |
4 | * Complete reimplementation | |
5 | * (C) 1997 Thomas Schoebel-Theuer, | |
6 | * with heavy changes by Linus Torvalds | |
7 | */ | |
8 | ||
9 | /* | |
10 | * Notes on the allocation strategy: | |
11 | * | |
12 | * The dcache is a master of the icache - whenever a dcache entry | |
13 | * exists, the inode will always exist. "iput()" is done either when | |
14 | * the dcache entry is deleted or garbage collected. | |
15 | */ | |
16 | ||
1da177e4 LT |
17 | #include <linux/syscalls.h> |
18 | #include <linux/string.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/fs.h> | |
7a91bf7f | 21 | #include <linux/fsnotify.h> |
1da177e4 LT |
22 | #include <linux/slab.h> |
23 | #include <linux/init.h> | |
1da177e4 LT |
24 | #include <linux/hash.h> |
25 | #include <linux/cache.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/file.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <linux/security.h> | |
31 | #include <linux/seqlock.h> | |
32 | #include <linux/swap.h> | |
33 | #include <linux/bootmem.h> | |
5ad4e53b | 34 | #include <linux/fs_struct.h> |
613afbf8 | 35 | #include <linux/hardirq.h> |
ceb5bdc2 NP |
36 | #include <linux/bit_spinlock.h> |
37 | #include <linux/rculist_bl.h> | |
268bb0ce | 38 | #include <linux/prefetch.h> |
dd179946 | 39 | #include <linux/ratelimit.h> |
07f3f05c | 40 | #include "internal.h" |
b2dba1af | 41 | #include "mount.h" |
1da177e4 | 42 | |
789680d1 NP |
43 | /* |
44 | * Usage: | |
873feea0 NP |
45 | * dcache->d_inode->i_lock protects: |
46 | * - i_dentry, d_alias, d_inode of aliases | |
ceb5bdc2 NP |
47 | * dcache_hash_bucket lock protects: |
48 | * - the dcache hash table | |
49 | * s_anon bl list spinlock protects: | |
50 | * - the s_anon list (see __d_drop) | |
23044507 NP |
51 | * dcache_lru_lock protects: |
52 | * - the dcache lru lists and counters | |
53 | * d_lock protects: | |
54 | * - d_flags | |
55 | * - d_name | |
56 | * - d_lru | |
b7ab39f6 | 57 | * - d_count |
da502956 | 58 | * - d_unhashed() |
2fd6b7f5 NP |
59 | * - d_parent and d_subdirs |
60 | * - childrens' d_child and d_parent | |
b23fb0a6 | 61 | * - d_alias, d_inode |
789680d1 NP |
62 | * |
63 | * Ordering: | |
873feea0 | 64 | * dentry->d_inode->i_lock |
b5c84bf6 NP |
65 | * dentry->d_lock |
66 | * dcache_lru_lock | |
ceb5bdc2 NP |
67 | * dcache_hash_bucket lock |
68 | * s_anon lock | |
789680d1 | 69 | * |
da502956 NP |
70 | * If there is an ancestor relationship: |
71 | * dentry->d_parent->...->d_parent->d_lock | |
72 | * ... | |
73 | * dentry->d_parent->d_lock | |
74 | * dentry->d_lock | |
75 | * | |
76 | * If no ancestor relationship: | |
789680d1 NP |
77 | * if (dentry1 < dentry2) |
78 | * dentry1->d_lock | |
79 | * dentry2->d_lock | |
80 | */ | |
fa3536cc | 81 | int sysctl_vfs_cache_pressure __read_mostly = 100; |
1da177e4 LT |
82 | EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure); |
83 | ||
23044507 | 84 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock); |
74c3cbe3 | 85 | __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock); |
1da177e4 | 86 | |
949854d0 | 87 | EXPORT_SYMBOL(rename_lock); |
1da177e4 | 88 | |
e18b890b | 89 | static struct kmem_cache *dentry_cache __read_mostly; |
1da177e4 | 90 | |
1da177e4 LT |
91 | /* |
92 | * This is the single most critical data structure when it comes | |
93 | * to the dcache: the hashtable for lookups. Somebody should try | |
94 | * to make this good - I've just made it work. | |
95 | * | |
96 | * This hash-function tries to avoid losing too many bits of hash | |
97 | * information, yet avoid using a prime hash-size or similar. | |
98 | */ | |
99 | #define D_HASHBITS d_hash_shift | |
100 | #define D_HASHMASK d_hash_mask | |
101 | ||
fa3536cc ED |
102 | static unsigned int d_hash_mask __read_mostly; |
103 | static unsigned int d_hash_shift __read_mostly; | |
ceb5bdc2 | 104 | |
b07ad996 | 105 | static struct hlist_bl_head *dentry_hashtable __read_mostly; |
ceb5bdc2 | 106 | |
8966be90 | 107 | static inline struct hlist_bl_head *d_hash(const struct dentry *parent, |
ceb5bdc2 NP |
108 | unsigned long hash) |
109 | { | |
110 | hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES; | |
111 | hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS); | |
112 | return dentry_hashtable + (hash & D_HASHMASK); | |
113 | } | |
114 | ||
1da177e4 LT |
115 | /* Statistics gathering. */ |
116 | struct dentry_stat_t dentry_stat = { | |
117 | .age_limit = 45, | |
118 | }; | |
119 | ||
3e880fb5 | 120 | static DEFINE_PER_CPU(unsigned int, nr_dentry); |
312d3ca8 CH |
121 | |
122 | #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) | |
3e880fb5 NP |
123 | static int get_nr_dentry(void) |
124 | { | |
125 | int i; | |
126 | int sum = 0; | |
127 | for_each_possible_cpu(i) | |
128 | sum += per_cpu(nr_dentry, i); | |
129 | return sum < 0 ? 0 : sum; | |
130 | } | |
131 | ||
312d3ca8 CH |
132 | int proc_nr_dentry(ctl_table *table, int write, void __user *buffer, |
133 | size_t *lenp, loff_t *ppos) | |
134 | { | |
3e880fb5 | 135 | dentry_stat.nr_dentry = get_nr_dentry(); |
312d3ca8 CH |
136 | return proc_dointvec(table, write, buffer, lenp, ppos); |
137 | } | |
138 | #endif | |
139 | ||
5483f18e LT |
140 | /* |
141 | * Compare 2 name strings, return 0 if they match, otherwise non-zero. | |
142 | * The strings are both count bytes long, and count is non-zero. | |
143 | */ | |
144 | static inline int dentry_cmp(const unsigned char *cs, size_t scount, | |
145 | const unsigned char *ct, size_t tcount) | |
146 | { | |
147 | if (scount != tcount) | |
148 | return 1; | |
149 | ||
150 | do { | |
151 | if (*cs != *ct) | |
152 | return 1; | |
153 | cs++; | |
154 | ct++; | |
155 | tcount--; | |
156 | } while (tcount); | |
157 | return 0; | |
158 | } | |
159 | ||
9c82ab9c | 160 | static void __d_free(struct rcu_head *head) |
1da177e4 | 161 | { |
9c82ab9c CH |
162 | struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); |
163 | ||
fd217f4d | 164 | WARN_ON(!list_empty(&dentry->d_alias)); |
1da177e4 LT |
165 | if (dname_external(dentry)) |
166 | kfree(dentry->d_name.name); | |
167 | kmem_cache_free(dentry_cache, dentry); | |
168 | } | |
169 | ||
170 | /* | |
b5c84bf6 | 171 | * no locks, please. |
1da177e4 LT |
172 | */ |
173 | static void d_free(struct dentry *dentry) | |
174 | { | |
b7ab39f6 | 175 | BUG_ON(dentry->d_count); |
3e880fb5 | 176 | this_cpu_dec(nr_dentry); |
1da177e4 LT |
177 | if (dentry->d_op && dentry->d_op->d_release) |
178 | dentry->d_op->d_release(dentry); | |
312d3ca8 | 179 | |
dea3667b LT |
180 | /* if dentry was never visible to RCU, immediate free is OK */ |
181 | if (!(dentry->d_flags & DCACHE_RCUACCESS)) | |
9c82ab9c | 182 | __d_free(&dentry->d_u.d_rcu); |
b3423415 | 183 | else |
9c82ab9c | 184 | call_rcu(&dentry->d_u.d_rcu, __d_free); |
1da177e4 LT |
185 | } |
186 | ||
31e6b01f NP |
187 | /** |
188 | * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups | |
ff5fdb61 | 189 | * @dentry: the target dentry |
31e6b01f NP |
190 | * After this call, in-progress rcu-walk path lookup will fail. This |
191 | * should be called after unhashing, and after changing d_inode (if | |
192 | * the dentry has not already been unhashed). | |
193 | */ | |
194 | static inline void dentry_rcuwalk_barrier(struct dentry *dentry) | |
195 | { | |
196 | assert_spin_locked(&dentry->d_lock); | |
197 | /* Go through a barrier */ | |
198 | write_seqcount_barrier(&dentry->d_seq); | |
199 | } | |
200 | ||
1da177e4 LT |
201 | /* |
202 | * Release the dentry's inode, using the filesystem | |
31e6b01f NP |
203 | * d_iput() operation if defined. Dentry has no refcount |
204 | * and is unhashed. | |
1da177e4 | 205 | */ |
858119e1 | 206 | static void dentry_iput(struct dentry * dentry) |
31f3e0b3 | 207 | __releases(dentry->d_lock) |
873feea0 | 208 | __releases(dentry->d_inode->i_lock) |
1da177e4 LT |
209 | { |
210 | struct inode *inode = dentry->d_inode; | |
211 | if (inode) { | |
212 | dentry->d_inode = NULL; | |
213 | list_del_init(&dentry->d_alias); | |
214 | spin_unlock(&dentry->d_lock); | |
873feea0 | 215 | spin_unlock(&inode->i_lock); |
f805fbda LT |
216 | if (!inode->i_nlink) |
217 | fsnotify_inoderemove(inode); | |
1da177e4 LT |
218 | if (dentry->d_op && dentry->d_op->d_iput) |
219 | dentry->d_op->d_iput(dentry, inode); | |
220 | else | |
221 | iput(inode); | |
222 | } else { | |
223 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
224 | } |
225 | } | |
226 | ||
31e6b01f NP |
227 | /* |
228 | * Release the dentry's inode, using the filesystem | |
229 | * d_iput() operation if defined. dentry remains in-use. | |
230 | */ | |
231 | static void dentry_unlink_inode(struct dentry * dentry) | |
232 | __releases(dentry->d_lock) | |
873feea0 | 233 | __releases(dentry->d_inode->i_lock) |
31e6b01f NP |
234 | { |
235 | struct inode *inode = dentry->d_inode; | |
236 | dentry->d_inode = NULL; | |
237 | list_del_init(&dentry->d_alias); | |
238 | dentry_rcuwalk_barrier(dentry); | |
239 | spin_unlock(&dentry->d_lock); | |
873feea0 | 240 | spin_unlock(&inode->i_lock); |
31e6b01f NP |
241 | if (!inode->i_nlink) |
242 | fsnotify_inoderemove(inode); | |
243 | if (dentry->d_op && dentry->d_op->d_iput) | |
244 | dentry->d_op->d_iput(dentry, inode); | |
245 | else | |
246 | iput(inode); | |
247 | } | |
248 | ||
da3bbdd4 | 249 | /* |
f0023bc6 | 250 | * dentry_lru_(add|del|prune|move_tail) must be called with d_lock held. |
da3bbdd4 KM |
251 | */ |
252 | static void dentry_lru_add(struct dentry *dentry) | |
253 | { | |
a4633357 | 254 | if (list_empty(&dentry->d_lru)) { |
23044507 | 255 | spin_lock(&dcache_lru_lock); |
a4633357 CH |
256 | list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
257 | dentry->d_sb->s_nr_dentry_unused++; | |
86c8749e | 258 | dentry_stat.nr_unused++; |
23044507 | 259 | spin_unlock(&dcache_lru_lock); |
a4633357 | 260 | } |
da3bbdd4 KM |
261 | } |
262 | ||
23044507 NP |
263 | static void __dentry_lru_del(struct dentry *dentry) |
264 | { | |
265 | list_del_init(&dentry->d_lru); | |
eaf5f907 | 266 | dentry->d_flags &= ~DCACHE_SHRINK_LIST; |
23044507 NP |
267 | dentry->d_sb->s_nr_dentry_unused--; |
268 | dentry_stat.nr_unused--; | |
269 | } | |
270 | ||
f0023bc6 SW |
271 | /* |
272 | * Remove a dentry with references from the LRU. | |
273 | */ | |
da3bbdd4 KM |
274 | static void dentry_lru_del(struct dentry *dentry) |
275 | { | |
276 | if (!list_empty(&dentry->d_lru)) { | |
23044507 NP |
277 | spin_lock(&dcache_lru_lock); |
278 | __dentry_lru_del(dentry); | |
279 | spin_unlock(&dcache_lru_lock); | |
da3bbdd4 KM |
280 | } |
281 | } | |
282 | ||
f0023bc6 SW |
283 | /* |
284 | * Remove a dentry that is unreferenced and about to be pruned | |
285 | * (unhashed and destroyed) from the LRU, and inform the file system. | |
286 | * This wrapper should be called _prior_ to unhashing a victim dentry. | |
287 | */ | |
288 | static void dentry_lru_prune(struct dentry *dentry) | |
289 | { | |
290 | if (!list_empty(&dentry->d_lru)) { | |
291 | if (dentry->d_flags & DCACHE_OP_PRUNE) | |
292 | dentry->d_op->d_prune(dentry); | |
293 | ||
294 | spin_lock(&dcache_lru_lock); | |
295 | __dentry_lru_del(dentry); | |
296 | spin_unlock(&dcache_lru_lock); | |
297 | } | |
298 | } | |
299 | ||
b48f03b3 | 300 | static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list) |
da3bbdd4 | 301 | { |
23044507 | 302 | spin_lock(&dcache_lru_lock); |
a4633357 | 303 | if (list_empty(&dentry->d_lru)) { |
b48f03b3 | 304 | list_add_tail(&dentry->d_lru, list); |
a4633357 | 305 | dentry->d_sb->s_nr_dentry_unused++; |
86c8749e | 306 | dentry_stat.nr_unused++; |
a4633357 | 307 | } else { |
b48f03b3 | 308 | list_move_tail(&dentry->d_lru, list); |
da3bbdd4 | 309 | } |
23044507 | 310 | spin_unlock(&dcache_lru_lock); |
da3bbdd4 KM |
311 | } |
312 | ||
d52b9086 MS |
313 | /** |
314 | * d_kill - kill dentry and return parent | |
315 | * @dentry: dentry to kill | |
ff5fdb61 | 316 | * @parent: parent dentry |
d52b9086 | 317 | * |
31f3e0b3 | 318 | * The dentry must already be unhashed and removed from the LRU. |
d52b9086 MS |
319 | * |
320 | * If this is the root of the dentry tree, return NULL. | |
23044507 | 321 | * |
b5c84bf6 NP |
322 | * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by |
323 | * d_kill. | |
d52b9086 | 324 | */ |
2fd6b7f5 | 325 | static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) |
31f3e0b3 | 326 | __releases(dentry->d_lock) |
2fd6b7f5 | 327 | __releases(parent->d_lock) |
873feea0 | 328 | __releases(dentry->d_inode->i_lock) |
d52b9086 | 329 | { |
d52b9086 | 330 | list_del(&dentry->d_u.d_child); |
c83ce989 TM |
331 | /* |
332 | * Inform try_to_ascend() that we are no longer attached to the | |
333 | * dentry tree | |
334 | */ | |
335 | dentry->d_flags |= DCACHE_DISCONNECTED; | |
2fd6b7f5 NP |
336 | if (parent) |
337 | spin_unlock(&parent->d_lock); | |
d52b9086 | 338 | dentry_iput(dentry); |
b7ab39f6 NP |
339 | /* |
340 | * dentry_iput drops the locks, at which point nobody (except | |
341 | * transient RCU lookups) can reach this dentry. | |
342 | */ | |
d52b9086 | 343 | d_free(dentry); |
871c0067 | 344 | return parent; |
d52b9086 MS |
345 | } |
346 | ||
c6627c60 DH |
347 | /* |
348 | * Unhash a dentry without inserting an RCU walk barrier or checking that | |
349 | * dentry->d_lock is locked. The caller must take care of that, if | |
350 | * appropriate. | |
351 | */ | |
352 | static void __d_shrink(struct dentry *dentry) | |
353 | { | |
354 | if (!d_unhashed(dentry)) { | |
355 | struct hlist_bl_head *b; | |
356 | if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) | |
357 | b = &dentry->d_sb->s_anon; | |
358 | else | |
359 | b = d_hash(dentry->d_parent, dentry->d_name.hash); | |
360 | ||
361 | hlist_bl_lock(b); | |
362 | __hlist_bl_del(&dentry->d_hash); | |
363 | dentry->d_hash.pprev = NULL; | |
364 | hlist_bl_unlock(b); | |
365 | } | |
366 | } | |
367 | ||
789680d1 NP |
368 | /** |
369 | * d_drop - drop a dentry | |
370 | * @dentry: dentry to drop | |
371 | * | |
372 | * d_drop() unhashes the entry from the parent dentry hashes, so that it won't | |
373 | * be found through a VFS lookup any more. Note that this is different from | |
374 | * deleting the dentry - d_delete will try to mark the dentry negative if | |
375 | * possible, giving a successful _negative_ lookup, while d_drop will | |
376 | * just make the cache lookup fail. | |
377 | * | |
378 | * d_drop() is used mainly for stuff that wants to invalidate a dentry for some | |
379 | * reason (NFS timeouts or autofs deletes). | |
380 | * | |
381 | * __d_drop requires dentry->d_lock. | |
382 | */ | |
383 | void __d_drop(struct dentry *dentry) | |
384 | { | |
dea3667b | 385 | if (!d_unhashed(dentry)) { |
c6627c60 | 386 | __d_shrink(dentry); |
dea3667b | 387 | dentry_rcuwalk_barrier(dentry); |
789680d1 NP |
388 | } |
389 | } | |
390 | EXPORT_SYMBOL(__d_drop); | |
391 | ||
392 | void d_drop(struct dentry *dentry) | |
393 | { | |
789680d1 NP |
394 | spin_lock(&dentry->d_lock); |
395 | __d_drop(dentry); | |
396 | spin_unlock(&dentry->d_lock); | |
789680d1 NP |
397 | } |
398 | EXPORT_SYMBOL(d_drop); | |
399 | ||
44396f4b JB |
400 | /* |
401 | * d_clear_need_lookup - drop a dentry from cache and clear the need lookup flag | |
402 | * @dentry: dentry to drop | |
403 | * | |
404 | * This is called when we do a lookup on a placeholder dentry that needed to be | |
405 | * looked up. The dentry should have been hashed in order for it to be found by | |
406 | * the lookup code, but now needs to be unhashed while we do the actual lookup | |
407 | * and clear the DCACHE_NEED_LOOKUP flag. | |
408 | */ | |
409 | void d_clear_need_lookup(struct dentry *dentry) | |
410 | { | |
411 | spin_lock(&dentry->d_lock); | |
412 | __d_drop(dentry); | |
413 | dentry->d_flags &= ~DCACHE_NEED_LOOKUP; | |
414 | spin_unlock(&dentry->d_lock); | |
415 | } | |
416 | EXPORT_SYMBOL(d_clear_need_lookup); | |
417 | ||
77812a1e NP |
418 | /* |
419 | * Finish off a dentry we've decided to kill. | |
420 | * dentry->d_lock must be held, returns with it unlocked. | |
421 | * If ref is non-zero, then decrement the refcount too. | |
422 | * Returns dentry requiring refcount drop, or NULL if we're done. | |
423 | */ | |
424 | static inline struct dentry *dentry_kill(struct dentry *dentry, int ref) | |
425 | __releases(dentry->d_lock) | |
426 | { | |
873feea0 | 427 | struct inode *inode; |
77812a1e NP |
428 | struct dentry *parent; |
429 | ||
873feea0 NP |
430 | inode = dentry->d_inode; |
431 | if (inode && !spin_trylock(&inode->i_lock)) { | |
77812a1e NP |
432 | relock: |
433 | spin_unlock(&dentry->d_lock); | |
434 | cpu_relax(); | |
435 | return dentry; /* try again with same dentry */ | |
436 | } | |
437 | if (IS_ROOT(dentry)) | |
438 | parent = NULL; | |
439 | else | |
440 | parent = dentry->d_parent; | |
441 | if (parent && !spin_trylock(&parent->d_lock)) { | |
873feea0 NP |
442 | if (inode) |
443 | spin_unlock(&inode->i_lock); | |
77812a1e NP |
444 | goto relock; |
445 | } | |
31e6b01f | 446 | |
77812a1e NP |
447 | if (ref) |
448 | dentry->d_count--; | |
f0023bc6 SW |
449 | /* |
450 | * if dentry was on the d_lru list delete it from there. | |
451 | * inform the fs via d_prune that this dentry is about to be | |
452 | * unhashed and destroyed. | |
453 | */ | |
454 | dentry_lru_prune(dentry); | |
77812a1e NP |
455 | /* if it was on the hash then remove it */ |
456 | __d_drop(dentry); | |
457 | return d_kill(dentry, parent); | |
458 | } | |
459 | ||
1da177e4 LT |
460 | /* |
461 | * This is dput | |
462 | * | |
463 | * This is complicated by the fact that we do not want to put | |
464 | * dentries that are no longer on any hash chain on the unused | |
465 | * list: we'd much rather just get rid of them immediately. | |
466 | * | |
467 | * However, that implies that we have to traverse the dentry | |
468 | * tree upwards to the parents which might _also_ now be | |
469 | * scheduled for deletion (it may have been only waiting for | |
470 | * its last child to go away). | |
471 | * | |
472 | * This tail recursion is done by hand as we don't want to depend | |
473 | * on the compiler to always get this right (gcc generally doesn't). | |
474 | * Real recursion would eat up our stack space. | |
475 | */ | |
476 | ||
477 | /* | |
478 | * dput - release a dentry | |
479 | * @dentry: dentry to release | |
480 | * | |
481 | * Release a dentry. This will drop the usage count and if appropriate | |
482 | * call the dentry unlink method as well as removing it from the queues and | |
483 | * releasing its resources. If the parent dentries were scheduled for release | |
484 | * they too may now get deleted. | |
1da177e4 | 485 | */ |
1da177e4 LT |
486 | void dput(struct dentry *dentry) |
487 | { | |
488 | if (!dentry) | |
489 | return; | |
490 | ||
491 | repeat: | |
b7ab39f6 | 492 | if (dentry->d_count == 1) |
1da177e4 | 493 | might_sleep(); |
1da177e4 | 494 | spin_lock(&dentry->d_lock); |
61f3dee4 NP |
495 | BUG_ON(!dentry->d_count); |
496 | if (dentry->d_count > 1) { | |
497 | dentry->d_count--; | |
1da177e4 | 498 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
499 | return; |
500 | } | |
501 | ||
fb045adb | 502 | if (dentry->d_flags & DCACHE_OP_DELETE) { |
1da177e4 | 503 | if (dentry->d_op->d_delete(dentry)) |
61f3dee4 | 504 | goto kill_it; |
1da177e4 | 505 | } |
265ac902 | 506 | |
1da177e4 LT |
507 | /* Unreachable? Get rid of it */ |
508 | if (d_unhashed(dentry)) | |
509 | goto kill_it; | |
265ac902 | 510 | |
44396f4b JB |
511 | /* |
512 | * If this dentry needs lookup, don't set the referenced flag so that it | |
513 | * is more likely to be cleaned up by the dcache shrinker in case of | |
514 | * memory pressure. | |
515 | */ | |
516 | if (!d_need_lookup(dentry)) | |
517 | dentry->d_flags |= DCACHE_REFERENCED; | |
a4633357 | 518 | dentry_lru_add(dentry); |
265ac902 | 519 | |
61f3dee4 NP |
520 | dentry->d_count--; |
521 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
522 | return; |
523 | ||
d52b9086 | 524 | kill_it: |
77812a1e | 525 | dentry = dentry_kill(dentry, 1); |
d52b9086 MS |
526 | if (dentry) |
527 | goto repeat; | |
1da177e4 | 528 | } |
ec4f8605 | 529 | EXPORT_SYMBOL(dput); |
1da177e4 LT |
530 | |
531 | /** | |
532 | * d_invalidate - invalidate a dentry | |
533 | * @dentry: dentry to invalidate | |
534 | * | |
535 | * Try to invalidate the dentry if it turns out to be | |
536 | * possible. If there are other dentries that can be | |
537 | * reached through this one we can't delete it and we | |
538 | * return -EBUSY. On success we return 0. | |
539 | * | |
540 | * no dcache lock. | |
541 | */ | |
542 | ||
543 | int d_invalidate(struct dentry * dentry) | |
544 | { | |
545 | /* | |
546 | * If it's already been dropped, return OK. | |
547 | */ | |
da502956 | 548 | spin_lock(&dentry->d_lock); |
1da177e4 | 549 | if (d_unhashed(dentry)) { |
da502956 | 550 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
551 | return 0; |
552 | } | |
553 | /* | |
554 | * Check whether to do a partial shrink_dcache | |
555 | * to get rid of unused child entries. | |
556 | */ | |
557 | if (!list_empty(&dentry->d_subdirs)) { | |
da502956 | 558 | spin_unlock(&dentry->d_lock); |
1da177e4 | 559 | shrink_dcache_parent(dentry); |
da502956 | 560 | spin_lock(&dentry->d_lock); |
1da177e4 LT |
561 | } |
562 | ||
563 | /* | |
564 | * Somebody else still using it? | |
565 | * | |
566 | * If it's a directory, we can't drop it | |
567 | * for fear of somebody re-populating it | |
568 | * with children (even though dropping it | |
569 | * would make it unreachable from the root, | |
570 | * we might still populate it if it was a | |
571 | * working directory or similar). | |
50e69630 AV |
572 | * We also need to leave mountpoints alone, |
573 | * directory or not. | |
1da177e4 | 574 | */ |
50e69630 AV |
575 | if (dentry->d_count > 1 && dentry->d_inode) { |
576 | if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { | |
1da177e4 | 577 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
578 | return -EBUSY; |
579 | } | |
580 | } | |
581 | ||
582 | __d_drop(dentry); | |
583 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
584 | return 0; |
585 | } | |
ec4f8605 | 586 | EXPORT_SYMBOL(d_invalidate); |
1da177e4 | 587 | |
b5c84bf6 | 588 | /* This must be called with d_lock held */ |
dc0474be | 589 | static inline void __dget_dlock(struct dentry *dentry) |
23044507 | 590 | { |
b7ab39f6 | 591 | dentry->d_count++; |
23044507 NP |
592 | } |
593 | ||
dc0474be | 594 | static inline void __dget(struct dentry *dentry) |
1da177e4 | 595 | { |
23044507 | 596 | spin_lock(&dentry->d_lock); |
dc0474be | 597 | __dget_dlock(dentry); |
23044507 | 598 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
599 | } |
600 | ||
b7ab39f6 NP |
601 | struct dentry *dget_parent(struct dentry *dentry) |
602 | { | |
603 | struct dentry *ret; | |
604 | ||
605 | repeat: | |
a734eb45 NP |
606 | /* |
607 | * Don't need rcu_dereference because we re-check it was correct under | |
608 | * the lock. | |
609 | */ | |
610 | rcu_read_lock(); | |
b7ab39f6 | 611 | ret = dentry->d_parent; |
a734eb45 NP |
612 | spin_lock(&ret->d_lock); |
613 | if (unlikely(ret != dentry->d_parent)) { | |
614 | spin_unlock(&ret->d_lock); | |
615 | rcu_read_unlock(); | |
b7ab39f6 NP |
616 | goto repeat; |
617 | } | |
a734eb45 | 618 | rcu_read_unlock(); |
b7ab39f6 NP |
619 | BUG_ON(!ret->d_count); |
620 | ret->d_count++; | |
621 | spin_unlock(&ret->d_lock); | |
b7ab39f6 NP |
622 | return ret; |
623 | } | |
624 | EXPORT_SYMBOL(dget_parent); | |
625 | ||
1da177e4 LT |
626 | /** |
627 | * d_find_alias - grab a hashed alias of inode | |
628 | * @inode: inode in question | |
629 | * @want_discon: flag, used by d_splice_alias, to request | |
630 | * that only a DISCONNECTED alias be returned. | |
631 | * | |
632 | * If inode has a hashed alias, or is a directory and has any alias, | |
633 | * acquire the reference to alias and return it. Otherwise return NULL. | |
634 | * Notice that if inode is a directory there can be only one alias and | |
635 | * it can be unhashed only if it has no children, or if it is the root | |
636 | * of a filesystem. | |
637 | * | |
21c0d8fd | 638 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
1da177e4 | 639 | * any other hashed alias over that one unless @want_discon is set, |
21c0d8fd | 640 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
1da177e4 | 641 | */ |
da502956 | 642 | static struct dentry *__d_find_alias(struct inode *inode, int want_discon) |
1da177e4 | 643 | { |
da502956 | 644 | struct dentry *alias, *discon_alias; |
1da177e4 | 645 | |
da502956 NP |
646 | again: |
647 | discon_alias = NULL; | |
648 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { | |
649 | spin_lock(&alias->d_lock); | |
1da177e4 | 650 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
21c0d8fd | 651 | if (IS_ROOT(alias) && |
da502956 | 652 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
1da177e4 | 653 | discon_alias = alias; |
da502956 | 654 | } else if (!want_discon) { |
dc0474be | 655 | __dget_dlock(alias); |
da502956 NP |
656 | spin_unlock(&alias->d_lock); |
657 | return alias; | |
658 | } | |
659 | } | |
660 | spin_unlock(&alias->d_lock); | |
661 | } | |
662 | if (discon_alias) { | |
663 | alias = discon_alias; | |
664 | spin_lock(&alias->d_lock); | |
665 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { | |
666 | if (IS_ROOT(alias) && | |
667 | (alias->d_flags & DCACHE_DISCONNECTED)) { | |
dc0474be | 668 | __dget_dlock(alias); |
da502956 | 669 | spin_unlock(&alias->d_lock); |
1da177e4 LT |
670 | return alias; |
671 | } | |
672 | } | |
da502956 NP |
673 | spin_unlock(&alias->d_lock); |
674 | goto again; | |
1da177e4 | 675 | } |
da502956 | 676 | return NULL; |
1da177e4 LT |
677 | } |
678 | ||
da502956 | 679 | struct dentry *d_find_alias(struct inode *inode) |
1da177e4 | 680 | { |
214fda1f DH |
681 | struct dentry *de = NULL; |
682 | ||
683 | if (!list_empty(&inode->i_dentry)) { | |
873feea0 | 684 | spin_lock(&inode->i_lock); |
214fda1f | 685 | de = __d_find_alias(inode, 0); |
873feea0 | 686 | spin_unlock(&inode->i_lock); |
214fda1f | 687 | } |
1da177e4 LT |
688 | return de; |
689 | } | |
ec4f8605 | 690 | EXPORT_SYMBOL(d_find_alias); |
1da177e4 LT |
691 | |
692 | /* | |
693 | * Try to kill dentries associated with this inode. | |
694 | * WARNING: you must own a reference to inode. | |
695 | */ | |
696 | void d_prune_aliases(struct inode *inode) | |
697 | { | |
0cdca3f9 | 698 | struct dentry *dentry; |
1da177e4 | 699 | restart: |
873feea0 | 700 | spin_lock(&inode->i_lock); |
0cdca3f9 | 701 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
1da177e4 | 702 | spin_lock(&dentry->d_lock); |
b7ab39f6 | 703 | if (!dentry->d_count) { |
dc0474be | 704 | __dget_dlock(dentry); |
1da177e4 LT |
705 | __d_drop(dentry); |
706 | spin_unlock(&dentry->d_lock); | |
873feea0 | 707 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
708 | dput(dentry); |
709 | goto restart; | |
710 | } | |
711 | spin_unlock(&dentry->d_lock); | |
712 | } | |
873feea0 | 713 | spin_unlock(&inode->i_lock); |
1da177e4 | 714 | } |
ec4f8605 | 715 | EXPORT_SYMBOL(d_prune_aliases); |
1da177e4 LT |
716 | |
717 | /* | |
77812a1e NP |
718 | * Try to throw away a dentry - free the inode, dput the parent. |
719 | * Requires dentry->d_lock is held, and dentry->d_count == 0. | |
720 | * Releases dentry->d_lock. | |
d702ccb3 | 721 | * |
77812a1e | 722 | * This may fail if locks cannot be acquired no problem, just try again. |
1da177e4 | 723 | */ |
77812a1e | 724 | static void try_prune_one_dentry(struct dentry *dentry) |
31f3e0b3 | 725 | __releases(dentry->d_lock) |
1da177e4 | 726 | { |
77812a1e | 727 | struct dentry *parent; |
d52b9086 | 728 | |
77812a1e | 729 | parent = dentry_kill(dentry, 0); |
d52b9086 | 730 | /* |
77812a1e NP |
731 | * If dentry_kill returns NULL, we have nothing more to do. |
732 | * if it returns the same dentry, trylocks failed. In either | |
733 | * case, just loop again. | |
734 | * | |
735 | * Otherwise, we need to prune ancestors too. This is necessary | |
736 | * to prevent quadratic behavior of shrink_dcache_parent(), but | |
737 | * is also expected to be beneficial in reducing dentry cache | |
738 | * fragmentation. | |
d52b9086 | 739 | */ |
77812a1e NP |
740 | if (!parent) |
741 | return; | |
742 | if (parent == dentry) | |
743 | return; | |
744 | ||
745 | /* Prune ancestors. */ | |
746 | dentry = parent; | |
d52b9086 | 747 | while (dentry) { |
b7ab39f6 | 748 | spin_lock(&dentry->d_lock); |
89e60548 NP |
749 | if (dentry->d_count > 1) { |
750 | dentry->d_count--; | |
751 | spin_unlock(&dentry->d_lock); | |
752 | return; | |
753 | } | |
77812a1e | 754 | dentry = dentry_kill(dentry, 1); |
d52b9086 | 755 | } |
1da177e4 LT |
756 | } |
757 | ||
3049cfe2 | 758 | static void shrink_dentry_list(struct list_head *list) |
1da177e4 | 759 | { |
da3bbdd4 | 760 | struct dentry *dentry; |
da3bbdd4 | 761 | |
ec33679d NP |
762 | rcu_read_lock(); |
763 | for (;;) { | |
ec33679d NP |
764 | dentry = list_entry_rcu(list->prev, struct dentry, d_lru); |
765 | if (&dentry->d_lru == list) | |
766 | break; /* empty */ | |
767 | spin_lock(&dentry->d_lock); | |
768 | if (dentry != list_entry(list->prev, struct dentry, d_lru)) { | |
769 | spin_unlock(&dentry->d_lock); | |
23044507 NP |
770 | continue; |
771 | } | |
772 | ||
1da177e4 LT |
773 | /* |
774 | * We found an inuse dentry which was not removed from | |
da3bbdd4 KM |
775 | * the LRU because of laziness during lookup. Do not free |
776 | * it - just keep it off the LRU list. | |
1da177e4 | 777 | */ |
b7ab39f6 | 778 | if (dentry->d_count) { |
ec33679d | 779 | dentry_lru_del(dentry); |
da3bbdd4 | 780 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
781 | continue; |
782 | } | |
ec33679d | 783 | |
ec33679d | 784 | rcu_read_unlock(); |
77812a1e NP |
785 | |
786 | try_prune_one_dentry(dentry); | |
787 | ||
ec33679d | 788 | rcu_read_lock(); |
da3bbdd4 | 789 | } |
ec33679d | 790 | rcu_read_unlock(); |
3049cfe2 CH |
791 | } |
792 | ||
793 | /** | |
b48f03b3 DC |
794 | * prune_dcache_sb - shrink the dcache |
795 | * @sb: superblock | |
796 | * @count: number of entries to try to free | |
797 | * | |
798 | * Attempt to shrink the superblock dcache LRU by @count entries. This is | |
799 | * done when we need more memory an called from the superblock shrinker | |
800 | * function. | |
3049cfe2 | 801 | * |
b48f03b3 DC |
802 | * This function may fail to free any resources if all the dentries are in |
803 | * use. | |
3049cfe2 | 804 | */ |
b48f03b3 | 805 | void prune_dcache_sb(struct super_block *sb, int count) |
3049cfe2 | 806 | { |
3049cfe2 CH |
807 | struct dentry *dentry; |
808 | LIST_HEAD(referenced); | |
809 | LIST_HEAD(tmp); | |
3049cfe2 | 810 | |
23044507 NP |
811 | relock: |
812 | spin_lock(&dcache_lru_lock); | |
3049cfe2 CH |
813 | while (!list_empty(&sb->s_dentry_lru)) { |
814 | dentry = list_entry(sb->s_dentry_lru.prev, | |
815 | struct dentry, d_lru); | |
816 | BUG_ON(dentry->d_sb != sb); | |
817 | ||
23044507 NP |
818 | if (!spin_trylock(&dentry->d_lock)) { |
819 | spin_unlock(&dcache_lru_lock); | |
820 | cpu_relax(); | |
821 | goto relock; | |
822 | } | |
823 | ||
b48f03b3 | 824 | if (dentry->d_flags & DCACHE_REFERENCED) { |
23044507 NP |
825 | dentry->d_flags &= ~DCACHE_REFERENCED; |
826 | list_move(&dentry->d_lru, &referenced); | |
3049cfe2 | 827 | spin_unlock(&dentry->d_lock); |
23044507 NP |
828 | } else { |
829 | list_move_tail(&dentry->d_lru, &tmp); | |
eaf5f907 | 830 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
23044507 | 831 | spin_unlock(&dentry->d_lock); |
b0d40c92 | 832 | if (!--count) |
23044507 | 833 | break; |
3049cfe2 | 834 | } |
ec33679d | 835 | cond_resched_lock(&dcache_lru_lock); |
3049cfe2 | 836 | } |
da3bbdd4 KM |
837 | if (!list_empty(&referenced)) |
838 | list_splice(&referenced, &sb->s_dentry_lru); | |
23044507 | 839 | spin_unlock(&dcache_lru_lock); |
ec33679d NP |
840 | |
841 | shrink_dentry_list(&tmp); | |
da3bbdd4 KM |
842 | } |
843 | ||
1da177e4 LT |
844 | /** |
845 | * shrink_dcache_sb - shrink dcache for a superblock | |
846 | * @sb: superblock | |
847 | * | |
3049cfe2 CH |
848 | * Shrink the dcache for the specified super block. This is used to free |
849 | * the dcache before unmounting a file system. | |
1da177e4 | 850 | */ |
3049cfe2 | 851 | void shrink_dcache_sb(struct super_block *sb) |
1da177e4 | 852 | { |
3049cfe2 CH |
853 | LIST_HEAD(tmp); |
854 | ||
23044507 | 855 | spin_lock(&dcache_lru_lock); |
3049cfe2 CH |
856 | while (!list_empty(&sb->s_dentry_lru)) { |
857 | list_splice_init(&sb->s_dentry_lru, &tmp); | |
ec33679d | 858 | spin_unlock(&dcache_lru_lock); |
3049cfe2 | 859 | shrink_dentry_list(&tmp); |
ec33679d | 860 | spin_lock(&dcache_lru_lock); |
3049cfe2 | 861 | } |
23044507 | 862 | spin_unlock(&dcache_lru_lock); |
1da177e4 | 863 | } |
ec4f8605 | 864 | EXPORT_SYMBOL(shrink_dcache_sb); |
1da177e4 | 865 | |
c636ebdb DH |
866 | /* |
867 | * destroy a single subtree of dentries for unmount | |
868 | * - see the comments on shrink_dcache_for_umount() for a description of the | |
869 | * locking | |
870 | */ | |
871 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) | |
872 | { | |
873 | struct dentry *parent; | |
874 | ||
875 | BUG_ON(!IS_ROOT(dentry)); | |
876 | ||
c636ebdb DH |
877 | for (;;) { |
878 | /* descend to the first leaf in the current subtree */ | |
43c1c9cd | 879 | while (!list_empty(&dentry->d_subdirs)) |
c636ebdb DH |
880 | dentry = list_entry(dentry->d_subdirs.next, |
881 | struct dentry, d_u.d_child); | |
c636ebdb DH |
882 | |
883 | /* consume the dentries from this leaf up through its parents | |
884 | * until we find one with children or run out altogether */ | |
885 | do { | |
886 | struct inode *inode; | |
887 | ||
f0023bc6 SW |
888 | /* |
889 | * remove the dentry from the lru, and inform | |
890 | * the fs that this dentry is about to be | |
891 | * unhashed and destroyed. | |
892 | */ | |
893 | dentry_lru_prune(dentry); | |
43c1c9cd DH |
894 | __d_shrink(dentry); |
895 | ||
b7ab39f6 | 896 | if (dentry->d_count != 0) { |
c636ebdb DH |
897 | printk(KERN_ERR |
898 | "BUG: Dentry %p{i=%lx,n=%s}" | |
899 | " still in use (%d)" | |
900 | " [unmount of %s %s]\n", | |
901 | dentry, | |
902 | dentry->d_inode ? | |
903 | dentry->d_inode->i_ino : 0UL, | |
904 | dentry->d_name.name, | |
b7ab39f6 | 905 | dentry->d_count, |
c636ebdb DH |
906 | dentry->d_sb->s_type->name, |
907 | dentry->d_sb->s_id); | |
908 | BUG(); | |
909 | } | |
910 | ||
2fd6b7f5 | 911 | if (IS_ROOT(dentry)) { |
c636ebdb | 912 | parent = NULL; |
2fd6b7f5 NP |
913 | list_del(&dentry->d_u.d_child); |
914 | } else { | |
871c0067 | 915 | parent = dentry->d_parent; |
b7ab39f6 | 916 | parent->d_count--; |
2fd6b7f5 | 917 | list_del(&dentry->d_u.d_child); |
871c0067 | 918 | } |
c636ebdb | 919 | |
c636ebdb DH |
920 | inode = dentry->d_inode; |
921 | if (inode) { | |
922 | dentry->d_inode = NULL; | |
923 | list_del_init(&dentry->d_alias); | |
924 | if (dentry->d_op && dentry->d_op->d_iput) | |
925 | dentry->d_op->d_iput(dentry, inode); | |
926 | else | |
927 | iput(inode); | |
928 | } | |
929 | ||
930 | d_free(dentry); | |
931 | ||
932 | /* finished when we fall off the top of the tree, | |
933 | * otherwise we ascend to the parent and move to the | |
934 | * next sibling if there is one */ | |
935 | if (!parent) | |
312d3ca8 | 936 | return; |
c636ebdb | 937 | dentry = parent; |
c636ebdb DH |
938 | } while (list_empty(&dentry->d_subdirs)); |
939 | ||
940 | dentry = list_entry(dentry->d_subdirs.next, | |
941 | struct dentry, d_u.d_child); | |
942 | } | |
943 | } | |
944 | ||
945 | /* | |
946 | * destroy the dentries attached to a superblock on unmounting | |
b5c84bf6 | 947 | * - we don't need to use dentry->d_lock because: |
c636ebdb DH |
948 | * - the superblock is detached from all mountings and open files, so the |
949 | * dentry trees will not be rearranged by the VFS | |
950 | * - s_umount is write-locked, so the memory pressure shrinker will ignore | |
951 | * any dentries belonging to this superblock that it comes across | |
952 | * - the filesystem itself is no longer permitted to rearrange the dentries | |
953 | * in this superblock | |
954 | */ | |
955 | void shrink_dcache_for_umount(struct super_block *sb) | |
956 | { | |
957 | struct dentry *dentry; | |
958 | ||
959 | if (down_read_trylock(&sb->s_umount)) | |
960 | BUG(); | |
961 | ||
962 | dentry = sb->s_root; | |
963 | sb->s_root = NULL; | |
b7ab39f6 | 964 | dentry->d_count--; |
c636ebdb DH |
965 | shrink_dcache_for_umount_subtree(dentry); |
966 | ||
ceb5bdc2 NP |
967 | while (!hlist_bl_empty(&sb->s_anon)) { |
968 | dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash); | |
c636ebdb DH |
969 | shrink_dcache_for_umount_subtree(dentry); |
970 | } | |
971 | } | |
972 | ||
c826cb7d LT |
973 | /* |
974 | * This tries to ascend one level of parenthood, but | |
975 | * we can race with renaming, so we need to re-check | |
976 | * the parenthood after dropping the lock and check | |
977 | * that the sequence number still matches. | |
978 | */ | |
979 | static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq) | |
980 | { | |
981 | struct dentry *new = old->d_parent; | |
982 | ||
983 | rcu_read_lock(); | |
984 | spin_unlock(&old->d_lock); | |
985 | spin_lock(&new->d_lock); | |
986 | ||
987 | /* | |
988 | * might go back up the wrong parent if we have had a rename | |
989 | * or deletion | |
990 | */ | |
991 | if (new != old->d_parent || | |
c83ce989 | 992 | (old->d_flags & DCACHE_DISCONNECTED) || |
c826cb7d LT |
993 | (!locked && read_seqretry(&rename_lock, seq))) { |
994 | spin_unlock(&new->d_lock); | |
995 | new = NULL; | |
996 | } | |
997 | rcu_read_unlock(); | |
998 | return new; | |
999 | } | |
1000 | ||
1001 | ||
1da177e4 LT |
1002 | /* |
1003 | * Search for at least 1 mount point in the dentry's subdirs. | |
1004 | * We descend to the next level whenever the d_subdirs | |
1005 | * list is non-empty and continue searching. | |
1006 | */ | |
1007 | ||
1008 | /** | |
1009 | * have_submounts - check for mounts over a dentry | |
1010 | * @parent: dentry to check. | |
1011 | * | |
1012 | * Return true if the parent or its subdirectories contain | |
1013 | * a mount point | |
1014 | */ | |
1da177e4 LT |
1015 | int have_submounts(struct dentry *parent) |
1016 | { | |
949854d0 | 1017 | struct dentry *this_parent; |
1da177e4 | 1018 | struct list_head *next; |
949854d0 | 1019 | unsigned seq; |
58db63d0 | 1020 | int locked = 0; |
949854d0 | 1021 | |
949854d0 | 1022 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
1023 | again: |
1024 | this_parent = parent; | |
1da177e4 | 1025 | |
1da177e4 LT |
1026 | if (d_mountpoint(parent)) |
1027 | goto positive; | |
2fd6b7f5 | 1028 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
1029 | repeat: |
1030 | next = this_parent->d_subdirs.next; | |
1031 | resume: | |
1032 | while (next != &this_parent->d_subdirs) { | |
1033 | struct list_head *tmp = next; | |
5160ee6f | 1034 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 | 1035 | next = tmp->next; |
2fd6b7f5 NP |
1036 | |
1037 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); | |
1da177e4 | 1038 | /* Have we found a mount point ? */ |
2fd6b7f5 NP |
1039 | if (d_mountpoint(dentry)) { |
1040 | spin_unlock(&dentry->d_lock); | |
1041 | spin_unlock(&this_parent->d_lock); | |
1da177e4 | 1042 | goto positive; |
2fd6b7f5 | 1043 | } |
1da177e4 | 1044 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
1045 | spin_unlock(&this_parent->d_lock); |
1046 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 1047 | this_parent = dentry; |
2fd6b7f5 | 1048 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
1049 | goto repeat; |
1050 | } | |
2fd6b7f5 | 1051 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
1052 | } |
1053 | /* | |
1054 | * All done at this level ... ascend and resume the search. | |
1055 | */ | |
1056 | if (this_parent != parent) { | |
c826cb7d LT |
1057 | struct dentry *child = this_parent; |
1058 | this_parent = try_to_ascend(this_parent, locked, seq); | |
1059 | if (!this_parent) | |
949854d0 | 1060 | goto rename_retry; |
949854d0 | 1061 | next = child->d_u.d_child.next; |
1da177e4 LT |
1062 | goto resume; |
1063 | } | |
2fd6b7f5 | 1064 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 1065 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1066 | goto rename_retry; |
58db63d0 NP |
1067 | if (locked) |
1068 | write_sequnlock(&rename_lock); | |
1da177e4 LT |
1069 | return 0; /* No mount points found in tree */ |
1070 | positive: | |
58db63d0 | 1071 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1072 | goto rename_retry; |
58db63d0 NP |
1073 | if (locked) |
1074 | write_sequnlock(&rename_lock); | |
1da177e4 | 1075 | return 1; |
58db63d0 NP |
1076 | |
1077 | rename_retry: | |
1078 | locked = 1; | |
1079 | write_seqlock(&rename_lock); | |
1080 | goto again; | |
1da177e4 | 1081 | } |
ec4f8605 | 1082 | EXPORT_SYMBOL(have_submounts); |
1da177e4 LT |
1083 | |
1084 | /* | |
1085 | * Search the dentry child list for the specified parent, | |
1086 | * and move any unused dentries to the end of the unused | |
1087 | * list for prune_dcache(). We descend to the next level | |
1088 | * whenever the d_subdirs list is non-empty and continue | |
1089 | * searching. | |
1090 | * | |
1091 | * It returns zero iff there are no unused children, | |
1092 | * otherwise it returns the number of children moved to | |
1093 | * the end of the unused list. This may not be the total | |
1094 | * number of unused children, because select_parent can | |
1095 | * drop the lock and return early due to latency | |
1096 | * constraints. | |
1097 | */ | |
b48f03b3 | 1098 | static int select_parent(struct dentry *parent, struct list_head *dispose) |
1da177e4 | 1099 | { |
949854d0 | 1100 | struct dentry *this_parent; |
1da177e4 | 1101 | struct list_head *next; |
949854d0 | 1102 | unsigned seq; |
1da177e4 | 1103 | int found = 0; |
58db63d0 | 1104 | int locked = 0; |
1da177e4 | 1105 | |
949854d0 | 1106 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
1107 | again: |
1108 | this_parent = parent; | |
2fd6b7f5 | 1109 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
1110 | repeat: |
1111 | next = this_parent->d_subdirs.next; | |
1112 | resume: | |
1113 | while (next != &this_parent->d_subdirs) { | |
1114 | struct list_head *tmp = next; | |
5160ee6f | 1115 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 LT |
1116 | next = tmp->next; |
1117 | ||
2fd6b7f5 | 1118 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
23044507 | 1119 | |
b48f03b3 DC |
1120 | /* |
1121 | * move only zero ref count dentries to the dispose list. | |
eaf5f907 MS |
1122 | * |
1123 | * Those which are presently on the shrink list, being processed | |
1124 | * by shrink_dentry_list(), shouldn't be moved. Otherwise the | |
1125 | * loop in shrink_dcache_parent() might not make any progress | |
1126 | * and loop forever. | |
1da177e4 | 1127 | */ |
eaf5f907 MS |
1128 | if (dentry->d_count) { |
1129 | dentry_lru_del(dentry); | |
1130 | } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { | |
b48f03b3 | 1131 | dentry_lru_move_list(dentry, dispose); |
eaf5f907 | 1132 | dentry->d_flags |= DCACHE_SHRINK_LIST; |
1da177e4 LT |
1133 | found++; |
1134 | } | |
1da177e4 LT |
1135 | /* |
1136 | * We can return to the caller if we have found some (this | |
1137 | * ensures forward progress). We'll be coming back to find | |
1138 | * the rest. | |
1139 | */ | |
2fd6b7f5 NP |
1140 | if (found && need_resched()) { |
1141 | spin_unlock(&dentry->d_lock); | |
1da177e4 | 1142 | goto out; |
2fd6b7f5 | 1143 | } |
1da177e4 LT |
1144 | |
1145 | /* | |
1146 | * Descend a level if the d_subdirs list is non-empty. | |
1147 | */ | |
1148 | if (!list_empty(&dentry->d_subdirs)) { | |
2fd6b7f5 NP |
1149 | spin_unlock(&this_parent->d_lock); |
1150 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 1151 | this_parent = dentry; |
2fd6b7f5 | 1152 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
1153 | goto repeat; |
1154 | } | |
2fd6b7f5 NP |
1155 | |
1156 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
1157 | } |
1158 | /* | |
1159 | * All done at this level ... ascend and resume the search. | |
1160 | */ | |
1161 | if (this_parent != parent) { | |
c826cb7d LT |
1162 | struct dentry *child = this_parent; |
1163 | this_parent = try_to_ascend(this_parent, locked, seq); | |
1164 | if (!this_parent) | |
949854d0 | 1165 | goto rename_retry; |
949854d0 | 1166 | next = child->d_u.d_child.next; |
1da177e4 LT |
1167 | goto resume; |
1168 | } | |
1169 | out: | |
2fd6b7f5 | 1170 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 1171 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1172 | goto rename_retry; |
58db63d0 NP |
1173 | if (locked) |
1174 | write_sequnlock(&rename_lock); | |
1da177e4 | 1175 | return found; |
58db63d0 NP |
1176 | |
1177 | rename_retry: | |
1178 | if (found) | |
1179 | return found; | |
1180 | locked = 1; | |
1181 | write_seqlock(&rename_lock); | |
1182 | goto again; | |
1da177e4 LT |
1183 | } |
1184 | ||
1185 | /** | |
1186 | * shrink_dcache_parent - prune dcache | |
1187 | * @parent: parent of entries to prune | |
1188 | * | |
1189 | * Prune the dcache to remove unused children of the parent dentry. | |
1190 | */ | |
1da177e4 LT |
1191 | void shrink_dcache_parent(struct dentry * parent) |
1192 | { | |
b48f03b3 | 1193 | LIST_HEAD(dispose); |
1da177e4 LT |
1194 | int found; |
1195 | ||
b48f03b3 DC |
1196 | while ((found = select_parent(parent, &dispose)) != 0) |
1197 | shrink_dentry_list(&dispose); | |
1da177e4 | 1198 | } |
ec4f8605 | 1199 | EXPORT_SYMBOL(shrink_dcache_parent); |
1da177e4 | 1200 | |
1da177e4 | 1201 | /** |
a4464dbc AV |
1202 | * __d_alloc - allocate a dcache entry |
1203 | * @sb: filesystem it will belong to | |
1da177e4 LT |
1204 | * @name: qstr of the name |
1205 | * | |
1206 | * Allocates a dentry. It returns %NULL if there is insufficient memory | |
1207 | * available. On a success the dentry is returned. The name passed in is | |
1208 | * copied and the copy passed in may be reused after this call. | |
1209 | */ | |
1210 | ||
a4464dbc | 1211 | struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) |
1da177e4 LT |
1212 | { |
1213 | struct dentry *dentry; | |
1214 | char *dname; | |
1215 | ||
e12ba74d | 1216 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
1da177e4 LT |
1217 | if (!dentry) |
1218 | return NULL; | |
1219 | ||
1220 | if (name->len > DNAME_INLINE_LEN-1) { | |
1221 | dname = kmalloc(name->len + 1, GFP_KERNEL); | |
1222 | if (!dname) { | |
1223 | kmem_cache_free(dentry_cache, dentry); | |
1224 | return NULL; | |
1225 | } | |
1226 | } else { | |
1227 | dname = dentry->d_iname; | |
1228 | } | |
1229 | dentry->d_name.name = dname; | |
1230 | ||
1231 | dentry->d_name.len = name->len; | |
1232 | dentry->d_name.hash = name->hash; | |
1233 | memcpy(dname, name->name, name->len); | |
1234 | dname[name->len] = 0; | |
1235 | ||
b7ab39f6 | 1236 | dentry->d_count = 1; |
dea3667b | 1237 | dentry->d_flags = 0; |
1da177e4 | 1238 | spin_lock_init(&dentry->d_lock); |
31e6b01f | 1239 | seqcount_init(&dentry->d_seq); |
1da177e4 | 1240 | dentry->d_inode = NULL; |
a4464dbc AV |
1241 | dentry->d_parent = dentry; |
1242 | dentry->d_sb = sb; | |
1da177e4 LT |
1243 | dentry->d_op = NULL; |
1244 | dentry->d_fsdata = NULL; | |
ceb5bdc2 | 1245 | INIT_HLIST_BL_NODE(&dentry->d_hash); |
1da177e4 LT |
1246 | INIT_LIST_HEAD(&dentry->d_lru); |
1247 | INIT_LIST_HEAD(&dentry->d_subdirs); | |
1248 | INIT_LIST_HEAD(&dentry->d_alias); | |
2fd6b7f5 | 1249 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
a4464dbc | 1250 | d_set_d_op(dentry, dentry->d_sb->s_d_op); |
1da177e4 | 1251 | |
3e880fb5 | 1252 | this_cpu_inc(nr_dentry); |
312d3ca8 | 1253 | |
1da177e4 LT |
1254 | return dentry; |
1255 | } | |
a4464dbc AV |
1256 | |
1257 | /** | |
1258 | * d_alloc - allocate a dcache entry | |
1259 | * @parent: parent of entry to allocate | |
1260 | * @name: qstr of the name | |
1261 | * | |
1262 | * Allocates a dentry. It returns %NULL if there is insufficient memory | |
1263 | * available. On a success the dentry is returned. The name passed in is | |
1264 | * copied and the copy passed in may be reused after this call. | |
1265 | */ | |
1266 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) | |
1267 | { | |
1268 | struct dentry *dentry = __d_alloc(parent->d_sb, name); | |
1269 | if (!dentry) | |
1270 | return NULL; | |
1271 | ||
1272 | spin_lock(&parent->d_lock); | |
1273 | /* | |
1274 | * don't need child lock because it is not subject | |
1275 | * to concurrency here | |
1276 | */ | |
1277 | __dget_dlock(parent); | |
1278 | dentry->d_parent = parent; | |
1279 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); | |
1280 | spin_unlock(&parent->d_lock); | |
1281 | ||
1282 | return dentry; | |
1283 | } | |
ec4f8605 | 1284 | EXPORT_SYMBOL(d_alloc); |
1da177e4 | 1285 | |
4b936885 NP |
1286 | struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) |
1287 | { | |
a4464dbc AV |
1288 | struct dentry *dentry = __d_alloc(sb, name); |
1289 | if (dentry) | |
4b936885 | 1290 | dentry->d_flags |= DCACHE_DISCONNECTED; |
4b936885 NP |
1291 | return dentry; |
1292 | } | |
1293 | EXPORT_SYMBOL(d_alloc_pseudo); | |
1294 | ||
1da177e4 LT |
1295 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) |
1296 | { | |
1297 | struct qstr q; | |
1298 | ||
1299 | q.name = name; | |
1300 | q.len = strlen(name); | |
1301 | q.hash = full_name_hash(q.name, q.len); | |
1302 | return d_alloc(parent, &q); | |
1303 | } | |
ef26ca97 | 1304 | EXPORT_SYMBOL(d_alloc_name); |
1da177e4 | 1305 | |
fb045adb NP |
1306 | void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) |
1307 | { | |
6f7f7caa LT |
1308 | WARN_ON_ONCE(dentry->d_op); |
1309 | WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | | |
fb045adb NP |
1310 | DCACHE_OP_COMPARE | |
1311 | DCACHE_OP_REVALIDATE | | |
1312 | DCACHE_OP_DELETE )); | |
1313 | dentry->d_op = op; | |
1314 | if (!op) | |
1315 | return; | |
1316 | if (op->d_hash) | |
1317 | dentry->d_flags |= DCACHE_OP_HASH; | |
1318 | if (op->d_compare) | |
1319 | dentry->d_flags |= DCACHE_OP_COMPARE; | |
1320 | if (op->d_revalidate) | |
1321 | dentry->d_flags |= DCACHE_OP_REVALIDATE; | |
1322 | if (op->d_delete) | |
1323 | dentry->d_flags |= DCACHE_OP_DELETE; | |
f0023bc6 SW |
1324 | if (op->d_prune) |
1325 | dentry->d_flags |= DCACHE_OP_PRUNE; | |
fb045adb NP |
1326 | |
1327 | } | |
1328 | EXPORT_SYMBOL(d_set_d_op); | |
1329 | ||
360da900 OH |
1330 | static void __d_instantiate(struct dentry *dentry, struct inode *inode) |
1331 | { | |
b23fb0a6 | 1332 | spin_lock(&dentry->d_lock); |
9875cf80 DH |
1333 | if (inode) { |
1334 | if (unlikely(IS_AUTOMOUNT(inode))) | |
1335 | dentry->d_flags |= DCACHE_NEED_AUTOMOUNT; | |
360da900 | 1336 | list_add(&dentry->d_alias, &inode->i_dentry); |
9875cf80 | 1337 | } |
360da900 | 1338 | dentry->d_inode = inode; |
31e6b01f | 1339 | dentry_rcuwalk_barrier(dentry); |
b23fb0a6 | 1340 | spin_unlock(&dentry->d_lock); |
360da900 OH |
1341 | fsnotify_d_instantiate(dentry, inode); |
1342 | } | |
1343 | ||
1da177e4 LT |
1344 | /** |
1345 | * d_instantiate - fill in inode information for a dentry | |
1346 | * @entry: dentry to complete | |
1347 | * @inode: inode to attach to this dentry | |
1348 | * | |
1349 | * Fill in inode information in the entry. | |
1350 | * | |
1351 | * This turns negative dentries into productive full members | |
1352 | * of society. | |
1353 | * | |
1354 | * NOTE! This assumes that the inode count has been incremented | |
1355 | * (or otherwise set) by the caller to indicate that it is now | |
1356 | * in use by the dcache. | |
1357 | */ | |
1358 | ||
1359 | void d_instantiate(struct dentry *entry, struct inode * inode) | |
1360 | { | |
28133c7b | 1361 | BUG_ON(!list_empty(&entry->d_alias)); |
873feea0 NP |
1362 | if (inode) |
1363 | spin_lock(&inode->i_lock); | |
360da900 | 1364 | __d_instantiate(entry, inode); |
873feea0 NP |
1365 | if (inode) |
1366 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
1367 | security_d_instantiate(entry, inode); |
1368 | } | |
ec4f8605 | 1369 | EXPORT_SYMBOL(d_instantiate); |
1da177e4 LT |
1370 | |
1371 | /** | |
1372 | * d_instantiate_unique - instantiate a non-aliased dentry | |
1373 | * @entry: dentry to instantiate | |
1374 | * @inode: inode to attach to this dentry | |
1375 | * | |
1376 | * Fill in inode information in the entry. On success, it returns NULL. | |
1377 | * If an unhashed alias of "entry" already exists, then we return the | |
e866cfa9 | 1378 | * aliased dentry instead and drop one reference to inode. |
1da177e4 LT |
1379 | * |
1380 | * Note that in order to avoid conflicts with rename() etc, the caller | |
1381 | * had better be holding the parent directory semaphore. | |
e866cfa9 OD |
1382 | * |
1383 | * This also assumes that the inode count has been incremented | |
1384 | * (or otherwise set) by the caller to indicate that it is now | |
1385 | * in use by the dcache. | |
1da177e4 | 1386 | */ |
770bfad8 DH |
1387 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
1388 | struct inode *inode) | |
1da177e4 LT |
1389 | { |
1390 | struct dentry *alias; | |
1391 | int len = entry->d_name.len; | |
1392 | const char *name = entry->d_name.name; | |
1393 | unsigned int hash = entry->d_name.hash; | |
1394 | ||
770bfad8 | 1395 | if (!inode) { |
360da900 | 1396 | __d_instantiate(entry, NULL); |
770bfad8 DH |
1397 | return NULL; |
1398 | } | |
1399 | ||
1da177e4 LT |
1400 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
1401 | struct qstr *qstr = &alias->d_name; | |
1402 | ||
9abca360 NP |
1403 | /* |
1404 | * Don't need alias->d_lock here, because aliases with | |
1405 | * d_parent == entry->d_parent are not subject to name or | |
1406 | * parent changes, because the parent inode i_mutex is held. | |
1407 | */ | |
1da177e4 LT |
1408 | if (qstr->hash != hash) |
1409 | continue; | |
1410 | if (alias->d_parent != entry->d_parent) | |
1411 | continue; | |
9d55c369 | 1412 | if (dentry_cmp(qstr->name, qstr->len, name, len)) |
1da177e4 | 1413 | continue; |
dc0474be | 1414 | __dget(alias); |
1da177e4 LT |
1415 | return alias; |
1416 | } | |
770bfad8 | 1417 | |
360da900 | 1418 | __d_instantiate(entry, inode); |
1da177e4 LT |
1419 | return NULL; |
1420 | } | |
770bfad8 DH |
1421 | |
1422 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) | |
1423 | { | |
1424 | struct dentry *result; | |
1425 | ||
1426 | BUG_ON(!list_empty(&entry->d_alias)); | |
1427 | ||
873feea0 NP |
1428 | if (inode) |
1429 | spin_lock(&inode->i_lock); | |
770bfad8 | 1430 | result = __d_instantiate_unique(entry, inode); |
873feea0 NP |
1431 | if (inode) |
1432 | spin_unlock(&inode->i_lock); | |
770bfad8 DH |
1433 | |
1434 | if (!result) { | |
1435 | security_d_instantiate(entry, inode); | |
1436 | return NULL; | |
1437 | } | |
1438 | ||
1439 | BUG_ON(!d_unhashed(result)); | |
1440 | iput(inode); | |
1441 | return result; | |
1442 | } | |
1443 | ||
1da177e4 LT |
1444 | EXPORT_SYMBOL(d_instantiate_unique); |
1445 | ||
1446 | /** | |
1447 | * d_alloc_root - allocate root dentry | |
1448 | * @root_inode: inode to allocate the root for | |
1449 | * | |
1450 | * Allocate a root ("/") dentry for the inode given. The inode is | |
1451 | * instantiated and returned. %NULL is returned if there is insufficient | |
1452 | * memory or the inode passed is %NULL. | |
1453 | */ | |
1454 | ||
1455 | struct dentry * d_alloc_root(struct inode * root_inode) | |
1456 | { | |
1457 | struct dentry *res = NULL; | |
1458 | ||
1459 | if (root_inode) { | |
1460 | static const struct qstr name = { .name = "/", .len = 1 }; | |
1461 | ||
a4464dbc AV |
1462 | res = __d_alloc(root_inode->i_sb, &name); |
1463 | if (res) | |
1da177e4 | 1464 | d_instantiate(res, root_inode); |
1da177e4 LT |
1465 | } |
1466 | return res; | |
1467 | } | |
ec4f8605 | 1468 | EXPORT_SYMBOL(d_alloc_root); |
1da177e4 | 1469 | |
adc0e91a AV |
1470 | struct dentry *d_make_root(struct inode *root_inode) |
1471 | { | |
1472 | struct dentry *res = NULL; | |
1473 | ||
1474 | if (root_inode) { | |
1475 | static const struct qstr name = { .name = "/", .len = 1 }; | |
1476 | ||
1477 | res = __d_alloc(root_inode->i_sb, &name); | |
1478 | if (res) | |
1479 | d_instantiate(res, root_inode); | |
1480 | else | |
1481 | iput(root_inode); | |
1482 | } | |
1483 | return res; | |
1484 | } | |
1485 | EXPORT_SYMBOL(d_make_root); | |
1486 | ||
d891eedb BF |
1487 | static struct dentry * __d_find_any_alias(struct inode *inode) |
1488 | { | |
1489 | struct dentry *alias; | |
1490 | ||
1491 | if (list_empty(&inode->i_dentry)) | |
1492 | return NULL; | |
1493 | alias = list_first_entry(&inode->i_dentry, struct dentry, d_alias); | |
1494 | __dget(alias); | |
1495 | return alias; | |
1496 | } | |
1497 | ||
46f72b34 SW |
1498 | /** |
1499 | * d_find_any_alias - find any alias for a given inode | |
1500 | * @inode: inode to find an alias for | |
1501 | * | |
1502 | * If any aliases exist for the given inode, take and return a | |
1503 | * reference for one of them. If no aliases exist, return %NULL. | |
1504 | */ | |
1505 | struct dentry *d_find_any_alias(struct inode *inode) | |
d891eedb BF |
1506 | { |
1507 | struct dentry *de; | |
1508 | ||
1509 | spin_lock(&inode->i_lock); | |
1510 | de = __d_find_any_alias(inode); | |
1511 | spin_unlock(&inode->i_lock); | |
1512 | return de; | |
1513 | } | |
46f72b34 | 1514 | EXPORT_SYMBOL(d_find_any_alias); |
d891eedb | 1515 | |
4ea3ada2 CH |
1516 | /** |
1517 | * d_obtain_alias - find or allocate a dentry for a given inode | |
1518 | * @inode: inode to allocate the dentry for | |
1519 | * | |
1520 | * Obtain a dentry for an inode resulting from NFS filehandle conversion or | |
1521 | * similar open by handle operations. The returned dentry may be anonymous, | |
1522 | * or may have a full name (if the inode was already in the cache). | |
1523 | * | |
1524 | * When called on a directory inode, we must ensure that the inode only ever | |
1525 | * has one dentry. If a dentry is found, that is returned instead of | |
1526 | * allocating a new one. | |
1527 | * | |
1528 | * On successful return, the reference to the inode has been transferred | |
44003728 CH |
1529 | * to the dentry. In case of an error the reference on the inode is released. |
1530 | * To make it easier to use in export operations a %NULL or IS_ERR inode may | |
1531 | * be passed in and will be the error will be propagate to the return value, | |
1532 | * with a %NULL @inode replaced by ERR_PTR(-ESTALE). | |
4ea3ada2 CH |
1533 | */ |
1534 | struct dentry *d_obtain_alias(struct inode *inode) | |
1535 | { | |
9308a612 CH |
1536 | static const struct qstr anonstring = { .name = "" }; |
1537 | struct dentry *tmp; | |
1538 | struct dentry *res; | |
4ea3ada2 CH |
1539 | |
1540 | if (!inode) | |
44003728 | 1541 | return ERR_PTR(-ESTALE); |
4ea3ada2 CH |
1542 | if (IS_ERR(inode)) |
1543 | return ERR_CAST(inode); | |
1544 | ||
d891eedb | 1545 | res = d_find_any_alias(inode); |
9308a612 CH |
1546 | if (res) |
1547 | goto out_iput; | |
1548 | ||
a4464dbc | 1549 | tmp = __d_alloc(inode->i_sb, &anonstring); |
9308a612 CH |
1550 | if (!tmp) { |
1551 | res = ERR_PTR(-ENOMEM); | |
1552 | goto out_iput; | |
4ea3ada2 | 1553 | } |
b5c84bf6 | 1554 | |
873feea0 | 1555 | spin_lock(&inode->i_lock); |
d891eedb | 1556 | res = __d_find_any_alias(inode); |
9308a612 | 1557 | if (res) { |
873feea0 | 1558 | spin_unlock(&inode->i_lock); |
9308a612 CH |
1559 | dput(tmp); |
1560 | goto out_iput; | |
1561 | } | |
1562 | ||
1563 | /* attach a disconnected dentry */ | |
1564 | spin_lock(&tmp->d_lock); | |
9308a612 CH |
1565 | tmp->d_inode = inode; |
1566 | tmp->d_flags |= DCACHE_DISCONNECTED; | |
9308a612 | 1567 | list_add(&tmp->d_alias, &inode->i_dentry); |
1879fd6a | 1568 | hlist_bl_lock(&tmp->d_sb->s_anon); |
ceb5bdc2 | 1569 | hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); |
1879fd6a | 1570 | hlist_bl_unlock(&tmp->d_sb->s_anon); |
9308a612 | 1571 | spin_unlock(&tmp->d_lock); |
873feea0 | 1572 | spin_unlock(&inode->i_lock); |
24ff6663 | 1573 | security_d_instantiate(tmp, inode); |
9308a612 | 1574 | |
9308a612 CH |
1575 | return tmp; |
1576 | ||
1577 | out_iput: | |
24ff6663 JB |
1578 | if (res && !IS_ERR(res)) |
1579 | security_d_instantiate(res, inode); | |
9308a612 CH |
1580 | iput(inode); |
1581 | return res; | |
4ea3ada2 | 1582 | } |
adc48720 | 1583 | EXPORT_SYMBOL(d_obtain_alias); |
1da177e4 LT |
1584 | |
1585 | /** | |
1586 | * d_splice_alias - splice a disconnected dentry into the tree if one exists | |
1587 | * @inode: the inode which may have a disconnected dentry | |
1588 | * @dentry: a negative dentry which we want to point to the inode. | |
1589 | * | |
1590 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and | |
1591 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry | |
1592 | * and return it, else simply d_add the inode to the dentry and return NULL. | |
1593 | * | |
1594 | * This is needed in the lookup routine of any filesystem that is exportable | |
1595 | * (via knfsd) so that we can build dcache paths to directories effectively. | |
1596 | * | |
1597 | * If a dentry was found and moved, then it is returned. Otherwise NULL | |
1598 | * is returned. This matches the expected return value of ->lookup. | |
1599 | * | |
1600 | */ | |
1601 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) | |
1602 | { | |
1603 | struct dentry *new = NULL; | |
1604 | ||
a9049376 AV |
1605 | if (IS_ERR(inode)) |
1606 | return ERR_CAST(inode); | |
1607 | ||
21c0d8fd | 1608 | if (inode && S_ISDIR(inode->i_mode)) { |
873feea0 | 1609 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1610 | new = __d_find_alias(inode, 1); |
1611 | if (new) { | |
1612 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); | |
873feea0 | 1613 | spin_unlock(&inode->i_lock); |
1da177e4 | 1614 | security_d_instantiate(new, inode); |
1da177e4 LT |
1615 | d_move(new, dentry); |
1616 | iput(inode); | |
1617 | } else { | |
873feea0 | 1618 | /* already taking inode->i_lock, so d_add() by hand */ |
360da900 | 1619 | __d_instantiate(dentry, inode); |
873feea0 | 1620 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1621 | security_d_instantiate(dentry, inode); |
1622 | d_rehash(dentry); | |
1623 | } | |
1624 | } else | |
1625 | d_add(dentry, inode); | |
1626 | return new; | |
1627 | } | |
ec4f8605 | 1628 | EXPORT_SYMBOL(d_splice_alias); |
1da177e4 | 1629 | |
9403540c BN |
1630 | /** |
1631 | * d_add_ci - lookup or allocate new dentry with case-exact name | |
1632 | * @inode: the inode case-insensitive lookup has found | |
1633 | * @dentry: the negative dentry that was passed to the parent's lookup func | |
1634 | * @name: the case-exact name to be associated with the returned dentry | |
1635 | * | |
1636 | * This is to avoid filling the dcache with case-insensitive names to the | |
1637 | * same inode, only the actual correct case is stored in the dcache for | |
1638 | * case-insensitive filesystems. | |
1639 | * | |
1640 | * For a case-insensitive lookup match and if the the case-exact dentry | |
1641 | * already exists in in the dcache, use it and return it. | |
1642 | * | |
1643 | * If no entry exists with the exact case name, allocate new dentry with | |
1644 | * the exact case, and return the spliced entry. | |
1645 | */ | |
e45b590b | 1646 | struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, |
9403540c BN |
1647 | struct qstr *name) |
1648 | { | |
1649 | int error; | |
1650 | struct dentry *found; | |
1651 | struct dentry *new; | |
1652 | ||
b6520c81 CH |
1653 | /* |
1654 | * First check if a dentry matching the name already exists, | |
1655 | * if not go ahead and create it now. | |
1656 | */ | |
9403540c | 1657 | found = d_hash_and_lookup(dentry->d_parent, name); |
9403540c BN |
1658 | if (!found) { |
1659 | new = d_alloc(dentry->d_parent, name); | |
1660 | if (!new) { | |
1661 | error = -ENOMEM; | |
1662 | goto err_out; | |
1663 | } | |
b6520c81 | 1664 | |
9403540c BN |
1665 | found = d_splice_alias(inode, new); |
1666 | if (found) { | |
1667 | dput(new); | |
1668 | return found; | |
1669 | } | |
1670 | return new; | |
1671 | } | |
b6520c81 CH |
1672 | |
1673 | /* | |
1674 | * If a matching dentry exists, and it's not negative use it. | |
1675 | * | |
1676 | * Decrement the reference count to balance the iget() done | |
1677 | * earlier on. | |
1678 | */ | |
9403540c BN |
1679 | if (found->d_inode) { |
1680 | if (unlikely(found->d_inode != inode)) { | |
1681 | /* This can't happen because bad inodes are unhashed. */ | |
1682 | BUG_ON(!is_bad_inode(inode)); | |
1683 | BUG_ON(!is_bad_inode(found->d_inode)); | |
1684 | } | |
9403540c BN |
1685 | iput(inode); |
1686 | return found; | |
1687 | } | |
b6520c81 | 1688 | |
9403540c | 1689 | /* |
44396f4b JB |
1690 | * We are going to instantiate this dentry, unhash it and clear the |
1691 | * lookup flag so we can do that. | |
9403540c | 1692 | */ |
44396f4b JB |
1693 | if (unlikely(d_need_lookup(found))) |
1694 | d_clear_need_lookup(found); | |
b6520c81 | 1695 | |
9403540c | 1696 | /* |
9403540c | 1697 | * Negative dentry: instantiate it unless the inode is a directory and |
b6520c81 | 1698 | * already has a dentry. |
9403540c | 1699 | */ |
4513d899 AV |
1700 | new = d_splice_alias(inode, found); |
1701 | if (new) { | |
1702 | dput(found); | |
1703 | found = new; | |
9403540c | 1704 | } |
4513d899 | 1705 | return found; |
9403540c BN |
1706 | |
1707 | err_out: | |
1708 | iput(inode); | |
1709 | return ERR_PTR(error); | |
1710 | } | |
ec4f8605 | 1711 | EXPORT_SYMBOL(d_add_ci); |
1da177e4 | 1712 | |
31e6b01f NP |
1713 | /** |
1714 | * __d_lookup_rcu - search for a dentry (racy, store-free) | |
1715 | * @parent: parent dentry | |
1716 | * @name: qstr of name we wish to find | |
1717 | * @seq: returns d_seq value at the point where the dentry was found | |
1718 | * @inode: returns dentry->d_inode when the inode was found valid. | |
1719 | * Returns: dentry, or NULL | |
1720 | * | |
1721 | * __d_lookup_rcu is the dcache lookup function for rcu-walk name | |
1722 | * resolution (store-free path walking) design described in | |
1723 | * Documentation/filesystems/path-lookup.txt. | |
1724 | * | |
1725 | * This is not to be used outside core vfs. | |
1726 | * | |
1727 | * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock | |
1728 | * held, and rcu_read_lock held. The returned dentry must not be stored into | |
1729 | * without taking d_lock and checking d_seq sequence count against @seq | |
1730 | * returned here. | |
1731 | * | |
1732 | * A refcount may be taken on the found dentry with the __d_rcu_to_refcount | |
1733 | * function. | |
1734 | * | |
1735 | * Alternatively, __d_lookup_rcu may be called again to look up the child of | |
1736 | * the returned dentry, so long as its parent's seqlock is checked after the | |
1737 | * child is looked up. Thus, an interlocking stepping of sequence lock checks | |
1738 | * is formed, giving integrity down the path walk. | |
1739 | */ | |
8966be90 LT |
1740 | struct dentry *__d_lookup_rcu(const struct dentry *parent, |
1741 | const struct qstr *name, | |
1742 | unsigned *seqp, struct inode **inode) | |
31e6b01f NP |
1743 | { |
1744 | unsigned int len = name->len; | |
1745 | unsigned int hash = name->hash; | |
1746 | const unsigned char *str = name->name; | |
b07ad996 | 1747 | struct hlist_bl_head *b = d_hash(parent, hash); |
ceb5bdc2 | 1748 | struct hlist_bl_node *node; |
31e6b01f NP |
1749 | struct dentry *dentry; |
1750 | ||
1751 | /* | |
1752 | * Note: There is significant duplication with __d_lookup_rcu which is | |
1753 | * required to prevent single threaded performance regressions | |
1754 | * especially on architectures where smp_rmb (in seqcounts) are costly. | |
1755 | * Keep the two functions in sync. | |
1756 | */ | |
1757 | ||
1758 | /* | |
1759 | * The hash list is protected using RCU. | |
1760 | * | |
1761 | * Carefully use d_seq when comparing a candidate dentry, to avoid | |
1762 | * races with d_move(). | |
1763 | * | |
1764 | * It is possible that concurrent renames can mess up our list | |
1765 | * walk here and result in missing our dentry, resulting in the | |
1766 | * false-negative result. d_lookup() protects against concurrent | |
1767 | * renames using rename_lock seqlock. | |
1768 | * | |
b0a4bb83 | 1769 | * See Documentation/filesystems/path-lookup.txt for more details. |
31e6b01f | 1770 | */ |
b07ad996 | 1771 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
8966be90 | 1772 | unsigned seq; |
31e6b01f NP |
1773 | struct inode *i; |
1774 | const char *tname; | |
1775 | int tlen; | |
1776 | ||
1777 | if (dentry->d_name.hash != hash) | |
1778 | continue; | |
1779 | ||
1780 | seqretry: | |
8966be90 | 1781 | seq = read_seqcount_begin(&dentry->d_seq); |
31e6b01f NP |
1782 | if (dentry->d_parent != parent) |
1783 | continue; | |
1784 | if (d_unhashed(dentry)) | |
1785 | continue; | |
1786 | tlen = dentry->d_name.len; | |
1787 | tname = dentry->d_name.name; | |
1788 | i = dentry->d_inode; | |
e1bb5782 | 1789 | prefetch(tname); |
31e6b01f NP |
1790 | /* |
1791 | * This seqcount check is required to ensure name and | |
1792 | * len are loaded atomically, so as not to walk off the | |
1793 | * edge of memory when walking. If we could load this | |
1794 | * atomically some other way, we could drop this check. | |
1795 | */ | |
8966be90 | 1796 | if (read_seqcount_retry(&dentry->d_seq, seq)) |
31e6b01f | 1797 | goto seqretry; |
830c0f0e | 1798 | if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { |
31e6b01f NP |
1799 | if (parent->d_op->d_compare(parent, *inode, |
1800 | dentry, i, | |
1801 | tlen, tname, name)) | |
1802 | continue; | |
1803 | } else { | |
9d55c369 | 1804 | if (dentry_cmp(tname, tlen, str, len)) |
31e6b01f NP |
1805 | continue; |
1806 | } | |
1807 | /* | |
1808 | * No extra seqcount check is required after the name | |
1809 | * compare. The caller must perform a seqcount check in | |
1810 | * order to do anything useful with the returned dentry | |
1811 | * anyway. | |
1812 | */ | |
8966be90 | 1813 | *seqp = seq; |
31e6b01f NP |
1814 | *inode = i; |
1815 | return dentry; | |
1816 | } | |
1817 | return NULL; | |
1818 | } | |
1819 | ||
1da177e4 LT |
1820 | /** |
1821 | * d_lookup - search for a dentry | |
1822 | * @parent: parent dentry | |
1823 | * @name: qstr of name we wish to find | |
b04f784e | 1824 | * Returns: dentry, or NULL |
1da177e4 | 1825 | * |
b04f784e NP |
1826 | * d_lookup searches the children of the parent dentry for the name in |
1827 | * question. If the dentry is found its reference count is incremented and the | |
1828 | * dentry is returned. The caller must use dput to free the entry when it has | |
1829 | * finished using it. %NULL is returned if the dentry does not exist. | |
1da177e4 | 1830 | */ |
31e6b01f | 1831 | struct dentry *d_lookup(struct dentry *parent, struct qstr *name) |
1da177e4 | 1832 | { |
31e6b01f | 1833 | struct dentry *dentry; |
949854d0 | 1834 | unsigned seq; |
1da177e4 LT |
1835 | |
1836 | do { | |
1837 | seq = read_seqbegin(&rename_lock); | |
1838 | dentry = __d_lookup(parent, name); | |
1839 | if (dentry) | |
1840 | break; | |
1841 | } while (read_seqretry(&rename_lock, seq)); | |
1842 | return dentry; | |
1843 | } | |
ec4f8605 | 1844 | EXPORT_SYMBOL(d_lookup); |
1da177e4 | 1845 | |
31e6b01f | 1846 | /** |
b04f784e NP |
1847 | * __d_lookup - search for a dentry (racy) |
1848 | * @parent: parent dentry | |
1849 | * @name: qstr of name we wish to find | |
1850 | * Returns: dentry, or NULL | |
1851 | * | |
1852 | * __d_lookup is like d_lookup, however it may (rarely) return a | |
1853 | * false-negative result due to unrelated rename activity. | |
1854 | * | |
1855 | * __d_lookup is slightly faster by avoiding rename_lock read seqlock, | |
1856 | * however it must be used carefully, eg. with a following d_lookup in | |
1857 | * the case of failure. | |
1858 | * | |
1859 | * __d_lookup callers must be commented. | |
1860 | */ | |
31e6b01f | 1861 | struct dentry *__d_lookup(struct dentry *parent, struct qstr *name) |
1da177e4 LT |
1862 | { |
1863 | unsigned int len = name->len; | |
1864 | unsigned int hash = name->hash; | |
1865 | const unsigned char *str = name->name; | |
b07ad996 | 1866 | struct hlist_bl_head *b = d_hash(parent, hash); |
ceb5bdc2 | 1867 | struct hlist_bl_node *node; |
31e6b01f | 1868 | struct dentry *found = NULL; |
665a7583 | 1869 | struct dentry *dentry; |
1da177e4 | 1870 | |
31e6b01f NP |
1871 | /* |
1872 | * Note: There is significant duplication with __d_lookup_rcu which is | |
1873 | * required to prevent single threaded performance regressions | |
1874 | * especially on architectures where smp_rmb (in seqcounts) are costly. | |
1875 | * Keep the two functions in sync. | |
1876 | */ | |
1877 | ||
b04f784e NP |
1878 | /* |
1879 | * The hash list is protected using RCU. | |
1880 | * | |
1881 | * Take d_lock when comparing a candidate dentry, to avoid races | |
1882 | * with d_move(). | |
1883 | * | |
1884 | * It is possible that concurrent renames can mess up our list | |
1885 | * walk here and result in missing our dentry, resulting in the | |
1886 | * false-negative result. d_lookup() protects against concurrent | |
1887 | * renames using rename_lock seqlock. | |
1888 | * | |
b0a4bb83 | 1889 | * See Documentation/filesystems/path-lookup.txt for more details. |
b04f784e | 1890 | */ |
1da177e4 LT |
1891 | rcu_read_lock(); |
1892 | ||
b07ad996 | 1893 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
31e6b01f NP |
1894 | const char *tname; |
1895 | int tlen; | |
1da177e4 | 1896 | |
1da177e4 LT |
1897 | if (dentry->d_name.hash != hash) |
1898 | continue; | |
1da177e4 LT |
1899 | |
1900 | spin_lock(&dentry->d_lock); | |
1da177e4 LT |
1901 | if (dentry->d_parent != parent) |
1902 | goto next; | |
d0185c08 LT |
1903 | if (d_unhashed(dentry)) |
1904 | goto next; | |
1905 | ||
1da177e4 LT |
1906 | /* |
1907 | * It is safe to compare names since d_move() cannot | |
1908 | * change the qstr (protected by d_lock). | |
1909 | */ | |
31e6b01f NP |
1910 | tlen = dentry->d_name.len; |
1911 | tname = dentry->d_name.name; | |
fb045adb | 1912 | if (parent->d_flags & DCACHE_OP_COMPARE) { |
621e155a NP |
1913 | if (parent->d_op->d_compare(parent, parent->d_inode, |
1914 | dentry, dentry->d_inode, | |
31e6b01f | 1915 | tlen, tname, name)) |
1da177e4 LT |
1916 | goto next; |
1917 | } else { | |
9d55c369 | 1918 | if (dentry_cmp(tname, tlen, str, len)) |
1da177e4 LT |
1919 | goto next; |
1920 | } | |
1921 | ||
b7ab39f6 | 1922 | dentry->d_count++; |
d0185c08 | 1923 | found = dentry; |
1da177e4 LT |
1924 | spin_unlock(&dentry->d_lock); |
1925 | break; | |
1926 | next: | |
1927 | spin_unlock(&dentry->d_lock); | |
1928 | } | |
1929 | rcu_read_unlock(); | |
1930 | ||
1931 | return found; | |
1932 | } | |
1933 | ||
3e7e241f EB |
1934 | /** |
1935 | * d_hash_and_lookup - hash the qstr then search for a dentry | |
1936 | * @dir: Directory to search in | |
1937 | * @name: qstr of name we wish to find | |
1938 | * | |
1939 | * On hash failure or on lookup failure NULL is returned. | |
1940 | */ | |
1941 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) | |
1942 | { | |
1943 | struct dentry *dentry = NULL; | |
1944 | ||
1945 | /* | |
1946 | * Check for a fs-specific hash function. Note that we must | |
1947 | * calculate the standard hash first, as the d_op->d_hash() | |
1948 | * routine may choose to leave the hash value unchanged. | |
1949 | */ | |
1950 | name->hash = full_name_hash(name->name, name->len); | |
fb045adb | 1951 | if (dir->d_flags & DCACHE_OP_HASH) { |
b1e6a015 | 1952 | if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0) |
3e7e241f EB |
1953 | goto out; |
1954 | } | |
1955 | dentry = d_lookup(dir, name); | |
1956 | out: | |
1957 | return dentry; | |
1958 | } | |
1959 | ||
1da177e4 | 1960 | /** |
786a5e15 | 1961 | * d_validate - verify dentry provided from insecure source (deprecated) |
1da177e4 | 1962 | * @dentry: The dentry alleged to be valid child of @dparent |
ff5fdb61 | 1963 | * @dparent: The parent dentry (known to be valid) |
1da177e4 LT |
1964 | * |
1965 | * An insecure source has sent us a dentry, here we verify it and dget() it. | |
1966 | * This is used by ncpfs in its readdir implementation. | |
1967 | * Zero is returned in the dentry is invalid. | |
786a5e15 NP |
1968 | * |
1969 | * This function is slow for big directories, and deprecated, do not use it. | |
1da177e4 | 1970 | */ |
d3a23e16 | 1971 | int d_validate(struct dentry *dentry, struct dentry *dparent) |
1da177e4 | 1972 | { |
786a5e15 | 1973 | struct dentry *child; |
d3a23e16 | 1974 | |
2fd6b7f5 | 1975 | spin_lock(&dparent->d_lock); |
786a5e15 NP |
1976 | list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { |
1977 | if (dentry == child) { | |
2fd6b7f5 | 1978 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
dc0474be | 1979 | __dget_dlock(dentry); |
2fd6b7f5 NP |
1980 | spin_unlock(&dentry->d_lock); |
1981 | spin_unlock(&dparent->d_lock); | |
1da177e4 LT |
1982 | return 1; |
1983 | } | |
1984 | } | |
2fd6b7f5 | 1985 | spin_unlock(&dparent->d_lock); |
786a5e15 | 1986 | |
1da177e4 LT |
1987 | return 0; |
1988 | } | |
ec4f8605 | 1989 | EXPORT_SYMBOL(d_validate); |
1da177e4 LT |
1990 | |
1991 | /* | |
1992 | * When a file is deleted, we have two options: | |
1993 | * - turn this dentry into a negative dentry | |
1994 | * - unhash this dentry and free it. | |
1995 | * | |
1996 | * Usually, we want to just turn this into | |
1997 | * a negative dentry, but if anybody else is | |
1998 | * currently using the dentry or the inode | |
1999 | * we can't do that and we fall back on removing | |
2000 | * it from the hash queues and waiting for | |
2001 | * it to be deleted later when it has no users | |
2002 | */ | |
2003 | ||
2004 | /** | |
2005 | * d_delete - delete a dentry | |
2006 | * @dentry: The dentry to delete | |
2007 | * | |
2008 | * Turn the dentry into a negative dentry if possible, otherwise | |
2009 | * remove it from the hash queues so it can be deleted later | |
2010 | */ | |
2011 | ||
2012 | void d_delete(struct dentry * dentry) | |
2013 | { | |
873feea0 | 2014 | struct inode *inode; |
7a91bf7f | 2015 | int isdir = 0; |
1da177e4 LT |
2016 | /* |
2017 | * Are we the only user? | |
2018 | */ | |
357f8e65 | 2019 | again: |
1da177e4 | 2020 | spin_lock(&dentry->d_lock); |
873feea0 NP |
2021 | inode = dentry->d_inode; |
2022 | isdir = S_ISDIR(inode->i_mode); | |
b7ab39f6 | 2023 | if (dentry->d_count == 1) { |
873feea0 | 2024 | if (inode && !spin_trylock(&inode->i_lock)) { |
357f8e65 NP |
2025 | spin_unlock(&dentry->d_lock); |
2026 | cpu_relax(); | |
2027 | goto again; | |
2028 | } | |
13e3c5e5 | 2029 | dentry->d_flags &= ~DCACHE_CANT_MOUNT; |
31e6b01f | 2030 | dentry_unlink_inode(dentry); |
7a91bf7f | 2031 | fsnotify_nameremove(dentry, isdir); |
1da177e4 LT |
2032 | return; |
2033 | } | |
2034 | ||
2035 | if (!d_unhashed(dentry)) | |
2036 | __d_drop(dentry); | |
2037 | ||
2038 | spin_unlock(&dentry->d_lock); | |
7a91bf7f JM |
2039 | |
2040 | fsnotify_nameremove(dentry, isdir); | |
1da177e4 | 2041 | } |
ec4f8605 | 2042 | EXPORT_SYMBOL(d_delete); |
1da177e4 | 2043 | |
b07ad996 | 2044 | static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) |
1da177e4 | 2045 | { |
ceb5bdc2 | 2046 | BUG_ON(!d_unhashed(entry)); |
1879fd6a | 2047 | hlist_bl_lock(b); |
dea3667b | 2048 | entry->d_flags |= DCACHE_RCUACCESS; |
b07ad996 | 2049 | hlist_bl_add_head_rcu(&entry->d_hash, b); |
1879fd6a | 2050 | hlist_bl_unlock(b); |
1da177e4 LT |
2051 | } |
2052 | ||
770bfad8 DH |
2053 | static void _d_rehash(struct dentry * entry) |
2054 | { | |
2055 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); | |
2056 | } | |
2057 | ||
1da177e4 LT |
2058 | /** |
2059 | * d_rehash - add an entry back to the hash | |
2060 | * @entry: dentry to add to the hash | |
2061 | * | |
2062 | * Adds a dentry to the hash according to its name. | |
2063 | */ | |
2064 | ||
2065 | void d_rehash(struct dentry * entry) | |
2066 | { | |
1da177e4 | 2067 | spin_lock(&entry->d_lock); |
770bfad8 | 2068 | _d_rehash(entry); |
1da177e4 | 2069 | spin_unlock(&entry->d_lock); |
1da177e4 | 2070 | } |
ec4f8605 | 2071 | EXPORT_SYMBOL(d_rehash); |
1da177e4 | 2072 | |
fb2d5b86 NP |
2073 | /** |
2074 | * dentry_update_name_case - update case insensitive dentry with a new name | |
2075 | * @dentry: dentry to be updated | |
2076 | * @name: new name | |
2077 | * | |
2078 | * Update a case insensitive dentry with new case of name. | |
2079 | * | |
2080 | * dentry must have been returned by d_lookup with name @name. Old and new | |
2081 | * name lengths must match (ie. no d_compare which allows mismatched name | |
2082 | * lengths). | |
2083 | * | |
2084 | * Parent inode i_mutex must be held over d_lookup and into this call (to | |
2085 | * keep renames and concurrent inserts, and readdir(2) away). | |
2086 | */ | |
2087 | void dentry_update_name_case(struct dentry *dentry, struct qstr *name) | |
2088 | { | |
7ebfa57f | 2089 | BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); |
fb2d5b86 NP |
2090 | BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ |
2091 | ||
fb2d5b86 | 2092 | spin_lock(&dentry->d_lock); |
31e6b01f | 2093 | write_seqcount_begin(&dentry->d_seq); |
fb2d5b86 | 2094 | memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); |
31e6b01f | 2095 | write_seqcount_end(&dentry->d_seq); |
fb2d5b86 | 2096 | spin_unlock(&dentry->d_lock); |
fb2d5b86 NP |
2097 | } |
2098 | EXPORT_SYMBOL(dentry_update_name_case); | |
2099 | ||
1da177e4 LT |
2100 | static void switch_names(struct dentry *dentry, struct dentry *target) |
2101 | { | |
2102 | if (dname_external(target)) { | |
2103 | if (dname_external(dentry)) { | |
2104 | /* | |
2105 | * Both external: swap the pointers | |
2106 | */ | |
9a8d5bb4 | 2107 | swap(target->d_name.name, dentry->d_name.name); |
1da177e4 LT |
2108 | } else { |
2109 | /* | |
2110 | * dentry:internal, target:external. Steal target's | |
2111 | * storage and make target internal. | |
2112 | */ | |
321bcf92 BF |
2113 | memcpy(target->d_iname, dentry->d_name.name, |
2114 | dentry->d_name.len + 1); | |
1da177e4 LT |
2115 | dentry->d_name.name = target->d_name.name; |
2116 | target->d_name.name = target->d_iname; | |
2117 | } | |
2118 | } else { | |
2119 | if (dname_external(dentry)) { | |
2120 | /* | |
2121 | * dentry:external, target:internal. Give dentry's | |
2122 | * storage to target and make dentry internal | |
2123 | */ | |
2124 | memcpy(dentry->d_iname, target->d_name.name, | |
2125 | target->d_name.len + 1); | |
2126 | target->d_name.name = dentry->d_name.name; | |
2127 | dentry->d_name.name = dentry->d_iname; | |
2128 | } else { | |
2129 | /* | |
2130 | * Both are internal. Just copy target to dentry | |
2131 | */ | |
2132 | memcpy(dentry->d_iname, target->d_name.name, | |
2133 | target->d_name.len + 1); | |
dc711ca3 AV |
2134 | dentry->d_name.len = target->d_name.len; |
2135 | return; | |
1da177e4 LT |
2136 | } |
2137 | } | |
9a8d5bb4 | 2138 | swap(dentry->d_name.len, target->d_name.len); |
1da177e4 LT |
2139 | } |
2140 | ||
2fd6b7f5 NP |
2141 | static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target) |
2142 | { | |
2143 | /* | |
2144 | * XXXX: do we really need to take target->d_lock? | |
2145 | */ | |
2146 | if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent) | |
2147 | spin_lock(&target->d_parent->d_lock); | |
2148 | else { | |
2149 | if (d_ancestor(dentry->d_parent, target->d_parent)) { | |
2150 | spin_lock(&dentry->d_parent->d_lock); | |
2151 | spin_lock_nested(&target->d_parent->d_lock, | |
2152 | DENTRY_D_LOCK_NESTED); | |
2153 | } else { | |
2154 | spin_lock(&target->d_parent->d_lock); | |
2155 | spin_lock_nested(&dentry->d_parent->d_lock, | |
2156 | DENTRY_D_LOCK_NESTED); | |
2157 | } | |
2158 | } | |
2159 | if (target < dentry) { | |
2160 | spin_lock_nested(&target->d_lock, 2); | |
2161 | spin_lock_nested(&dentry->d_lock, 3); | |
2162 | } else { | |
2163 | spin_lock_nested(&dentry->d_lock, 2); | |
2164 | spin_lock_nested(&target->d_lock, 3); | |
2165 | } | |
2166 | } | |
2167 | ||
2168 | static void dentry_unlock_parents_for_move(struct dentry *dentry, | |
2169 | struct dentry *target) | |
2170 | { | |
2171 | if (target->d_parent != dentry->d_parent) | |
2172 | spin_unlock(&dentry->d_parent->d_lock); | |
2173 | if (target->d_parent != target) | |
2174 | spin_unlock(&target->d_parent->d_lock); | |
2175 | } | |
2176 | ||
1da177e4 | 2177 | /* |
2fd6b7f5 NP |
2178 | * When switching names, the actual string doesn't strictly have to |
2179 | * be preserved in the target - because we're dropping the target | |
2180 | * anyway. As such, we can just do a simple memcpy() to copy over | |
2181 | * the new name before we switch. | |
2182 | * | |
2183 | * Note that we have to be a lot more careful about getting the hash | |
2184 | * switched - we have to switch the hash value properly even if it | |
2185 | * then no longer matches the actual (corrupted) string of the target. | |
2186 | * The hash value has to match the hash queue that the dentry is on.. | |
1da177e4 | 2187 | */ |
9eaef27b | 2188 | /* |
18367501 | 2189 | * __d_move - move a dentry |
1da177e4 LT |
2190 | * @dentry: entry to move |
2191 | * @target: new dentry | |
2192 | * | |
2193 | * Update the dcache to reflect the move of a file name. Negative | |
c46c8877 JL |
2194 | * dcache entries should not be moved in this way. Caller must hold |
2195 | * rename_lock, the i_mutex of the source and target directories, | |
2196 | * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). | |
1da177e4 | 2197 | */ |
18367501 | 2198 | static void __d_move(struct dentry * dentry, struct dentry * target) |
1da177e4 | 2199 | { |
1da177e4 LT |
2200 | if (!dentry->d_inode) |
2201 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); | |
2202 | ||
2fd6b7f5 NP |
2203 | BUG_ON(d_ancestor(dentry, target)); |
2204 | BUG_ON(d_ancestor(target, dentry)); | |
2205 | ||
2fd6b7f5 | 2206 | dentry_lock_for_move(dentry, target); |
1da177e4 | 2207 | |
31e6b01f NP |
2208 | write_seqcount_begin(&dentry->d_seq); |
2209 | write_seqcount_begin(&target->d_seq); | |
2210 | ||
ceb5bdc2 NP |
2211 | /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ |
2212 | ||
2213 | /* | |
2214 | * Move the dentry to the target hash queue. Don't bother checking | |
2215 | * for the same hash queue because of how unlikely it is. | |
2216 | */ | |
2217 | __d_drop(dentry); | |
789680d1 | 2218 | __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); |
1da177e4 LT |
2219 | |
2220 | /* Unhash the target: dput() will then get rid of it */ | |
2221 | __d_drop(target); | |
2222 | ||
5160ee6f ED |
2223 | list_del(&dentry->d_u.d_child); |
2224 | list_del(&target->d_u.d_child); | |
1da177e4 LT |
2225 | |
2226 | /* Switch the names.. */ | |
2227 | switch_names(dentry, target); | |
9a8d5bb4 | 2228 | swap(dentry->d_name.hash, target->d_name.hash); |
1da177e4 LT |
2229 | |
2230 | /* ... and switch the parents */ | |
2231 | if (IS_ROOT(dentry)) { | |
2232 | dentry->d_parent = target->d_parent; | |
2233 | target->d_parent = target; | |
5160ee6f | 2234 | INIT_LIST_HEAD(&target->d_u.d_child); |
1da177e4 | 2235 | } else { |
9a8d5bb4 | 2236 | swap(dentry->d_parent, target->d_parent); |
1da177e4 LT |
2237 | |
2238 | /* And add them back to the (new) parent lists */ | |
5160ee6f | 2239 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
1da177e4 LT |
2240 | } |
2241 | ||
5160ee6f | 2242 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
2fd6b7f5 | 2243 | |
31e6b01f NP |
2244 | write_seqcount_end(&target->d_seq); |
2245 | write_seqcount_end(&dentry->d_seq); | |
2246 | ||
2fd6b7f5 | 2247 | dentry_unlock_parents_for_move(dentry, target); |
1da177e4 | 2248 | spin_unlock(&target->d_lock); |
c32ccd87 | 2249 | fsnotify_d_move(dentry); |
1da177e4 | 2250 | spin_unlock(&dentry->d_lock); |
18367501 AV |
2251 | } |
2252 | ||
2253 | /* | |
2254 | * d_move - move a dentry | |
2255 | * @dentry: entry to move | |
2256 | * @target: new dentry | |
2257 | * | |
2258 | * Update the dcache to reflect the move of a file name. Negative | |
c46c8877 JL |
2259 | * dcache entries should not be moved in this way. See the locking |
2260 | * requirements for __d_move. | |
18367501 AV |
2261 | */ |
2262 | void d_move(struct dentry *dentry, struct dentry *target) | |
2263 | { | |
2264 | write_seqlock(&rename_lock); | |
2265 | __d_move(dentry, target); | |
1da177e4 | 2266 | write_sequnlock(&rename_lock); |
9eaef27b | 2267 | } |
ec4f8605 | 2268 | EXPORT_SYMBOL(d_move); |
1da177e4 | 2269 | |
e2761a11 OH |
2270 | /** |
2271 | * d_ancestor - search for an ancestor | |
2272 | * @p1: ancestor dentry | |
2273 | * @p2: child dentry | |
2274 | * | |
2275 | * Returns the ancestor dentry of p2 which is a child of p1, if p1 is | |
2276 | * an ancestor of p2, else NULL. | |
9eaef27b | 2277 | */ |
e2761a11 | 2278 | struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) |
9eaef27b TM |
2279 | { |
2280 | struct dentry *p; | |
2281 | ||
871c0067 | 2282 | for (p = p2; !IS_ROOT(p); p = p->d_parent) { |
9eaef27b | 2283 | if (p->d_parent == p1) |
e2761a11 | 2284 | return p; |
9eaef27b | 2285 | } |
e2761a11 | 2286 | return NULL; |
9eaef27b TM |
2287 | } |
2288 | ||
2289 | /* | |
2290 | * This helper attempts to cope with remotely renamed directories | |
2291 | * | |
2292 | * It assumes that the caller is already holding | |
18367501 | 2293 | * dentry->d_parent->d_inode->i_mutex, inode->i_lock and rename_lock |
9eaef27b TM |
2294 | * |
2295 | * Note: If ever the locking in lock_rename() changes, then please | |
2296 | * remember to update this too... | |
9eaef27b | 2297 | */ |
873feea0 NP |
2298 | static struct dentry *__d_unalias(struct inode *inode, |
2299 | struct dentry *dentry, struct dentry *alias) | |
9eaef27b TM |
2300 | { |
2301 | struct mutex *m1 = NULL, *m2 = NULL; | |
2302 | struct dentry *ret; | |
2303 | ||
2304 | /* If alias and dentry share a parent, then no extra locks required */ | |
2305 | if (alias->d_parent == dentry->d_parent) | |
2306 | goto out_unalias; | |
2307 | ||
9eaef27b TM |
2308 | /* See lock_rename() */ |
2309 | ret = ERR_PTR(-EBUSY); | |
2310 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) | |
2311 | goto out_err; | |
2312 | m1 = &dentry->d_sb->s_vfs_rename_mutex; | |
2313 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) | |
2314 | goto out_err; | |
2315 | m2 = &alias->d_parent->d_inode->i_mutex; | |
2316 | out_unalias: | |
18367501 | 2317 | __d_move(alias, dentry); |
9eaef27b TM |
2318 | ret = alias; |
2319 | out_err: | |
873feea0 | 2320 | spin_unlock(&inode->i_lock); |
9eaef27b TM |
2321 | if (m2) |
2322 | mutex_unlock(m2); | |
2323 | if (m1) | |
2324 | mutex_unlock(m1); | |
2325 | return ret; | |
2326 | } | |
2327 | ||
770bfad8 DH |
2328 | /* |
2329 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a | |
2330 | * named dentry in place of the dentry to be replaced. | |
2fd6b7f5 | 2331 | * returns with anon->d_lock held! |
770bfad8 DH |
2332 | */ |
2333 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) | |
2334 | { | |
2335 | struct dentry *dparent, *aparent; | |
2336 | ||
2fd6b7f5 | 2337 | dentry_lock_for_move(anon, dentry); |
770bfad8 | 2338 | |
31e6b01f NP |
2339 | write_seqcount_begin(&dentry->d_seq); |
2340 | write_seqcount_begin(&anon->d_seq); | |
2341 | ||
770bfad8 DH |
2342 | dparent = dentry->d_parent; |
2343 | aparent = anon->d_parent; | |
2344 | ||
2fd6b7f5 NP |
2345 | switch_names(dentry, anon); |
2346 | swap(dentry->d_name.hash, anon->d_name.hash); | |
2347 | ||
770bfad8 DH |
2348 | dentry->d_parent = (aparent == anon) ? dentry : aparent; |
2349 | list_del(&dentry->d_u.d_child); | |
2350 | if (!IS_ROOT(dentry)) | |
2351 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); | |
2352 | else | |
2353 | INIT_LIST_HEAD(&dentry->d_u.d_child); | |
2354 | ||
2355 | anon->d_parent = (dparent == dentry) ? anon : dparent; | |
2356 | list_del(&anon->d_u.d_child); | |
2357 | if (!IS_ROOT(anon)) | |
2358 | list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs); | |
2359 | else | |
2360 | INIT_LIST_HEAD(&anon->d_u.d_child); | |
2361 | ||
31e6b01f NP |
2362 | write_seqcount_end(&dentry->d_seq); |
2363 | write_seqcount_end(&anon->d_seq); | |
2364 | ||
2fd6b7f5 NP |
2365 | dentry_unlock_parents_for_move(anon, dentry); |
2366 | spin_unlock(&dentry->d_lock); | |
2367 | ||
2368 | /* anon->d_lock still locked, returns locked */ | |
770bfad8 DH |
2369 | anon->d_flags &= ~DCACHE_DISCONNECTED; |
2370 | } | |
2371 | ||
2372 | /** | |
2373 | * d_materialise_unique - introduce an inode into the tree | |
2374 | * @dentry: candidate dentry | |
2375 | * @inode: inode to bind to the dentry, to which aliases may be attached | |
2376 | * | |
2377 | * Introduces an dentry into the tree, substituting an extant disconnected | |
c46c8877 JL |
2378 | * root directory alias in its place if there is one. Caller must hold the |
2379 | * i_mutex of the parent directory. | |
770bfad8 DH |
2380 | */ |
2381 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) | |
2382 | { | |
9eaef27b | 2383 | struct dentry *actual; |
770bfad8 DH |
2384 | |
2385 | BUG_ON(!d_unhashed(dentry)); | |
2386 | ||
770bfad8 DH |
2387 | if (!inode) { |
2388 | actual = dentry; | |
360da900 | 2389 | __d_instantiate(dentry, NULL); |
357f8e65 NP |
2390 | d_rehash(actual); |
2391 | goto out_nolock; | |
770bfad8 DH |
2392 | } |
2393 | ||
873feea0 | 2394 | spin_lock(&inode->i_lock); |
357f8e65 | 2395 | |
9eaef27b TM |
2396 | if (S_ISDIR(inode->i_mode)) { |
2397 | struct dentry *alias; | |
2398 | ||
2399 | /* Does an aliased dentry already exist? */ | |
2400 | alias = __d_find_alias(inode, 0); | |
2401 | if (alias) { | |
2402 | actual = alias; | |
18367501 AV |
2403 | write_seqlock(&rename_lock); |
2404 | ||
2405 | if (d_ancestor(alias, dentry)) { | |
2406 | /* Check for loops */ | |
2407 | actual = ERR_PTR(-ELOOP); | |
2408 | } else if (IS_ROOT(alias)) { | |
2409 | /* Is this an anonymous mountpoint that we | |
2410 | * could splice into our tree? */ | |
9eaef27b | 2411 | __d_materialise_dentry(dentry, alias); |
18367501 | 2412 | write_sequnlock(&rename_lock); |
9eaef27b TM |
2413 | __d_drop(alias); |
2414 | goto found; | |
18367501 AV |
2415 | } else { |
2416 | /* Nope, but we must(!) avoid directory | |
2417 | * aliasing */ | |
2418 | actual = __d_unalias(inode, dentry, alias); | |
9eaef27b | 2419 | } |
18367501 | 2420 | write_sequnlock(&rename_lock); |
dd179946 DH |
2421 | if (IS_ERR(actual)) { |
2422 | if (PTR_ERR(actual) == -ELOOP) | |
2423 | pr_warn_ratelimited( | |
2424 | "VFS: Lookup of '%s' in %s %s" | |
2425 | " would have caused loop\n", | |
2426 | dentry->d_name.name, | |
2427 | inode->i_sb->s_type->name, | |
2428 | inode->i_sb->s_id); | |
9eaef27b | 2429 | dput(alias); |
dd179946 | 2430 | } |
9eaef27b TM |
2431 | goto out_nolock; |
2432 | } | |
770bfad8 DH |
2433 | } |
2434 | ||
2435 | /* Add a unique reference */ | |
2436 | actual = __d_instantiate_unique(dentry, inode); | |
2437 | if (!actual) | |
2438 | actual = dentry; | |
357f8e65 NP |
2439 | else |
2440 | BUG_ON(!d_unhashed(actual)); | |
770bfad8 | 2441 | |
770bfad8 DH |
2442 | spin_lock(&actual->d_lock); |
2443 | found: | |
2444 | _d_rehash(actual); | |
2445 | spin_unlock(&actual->d_lock); | |
873feea0 | 2446 | spin_unlock(&inode->i_lock); |
9eaef27b | 2447 | out_nolock: |
770bfad8 DH |
2448 | if (actual == dentry) { |
2449 | security_d_instantiate(dentry, inode); | |
2450 | return NULL; | |
2451 | } | |
2452 | ||
2453 | iput(inode); | |
2454 | return actual; | |
770bfad8 | 2455 | } |
ec4f8605 | 2456 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
770bfad8 | 2457 | |
cdd16d02 | 2458 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
6092d048 RP |
2459 | { |
2460 | *buflen -= namelen; | |
2461 | if (*buflen < 0) | |
2462 | return -ENAMETOOLONG; | |
2463 | *buffer -= namelen; | |
2464 | memcpy(*buffer, str, namelen); | |
2465 | return 0; | |
2466 | } | |
2467 | ||
cdd16d02 MS |
2468 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
2469 | { | |
2470 | return prepend(buffer, buflen, name->name, name->len); | |
2471 | } | |
2472 | ||
1da177e4 | 2473 | /** |
208898c1 | 2474 | * prepend_path - Prepend path string to a buffer |
9d1bc601 | 2475 | * @path: the dentry/vfsmount to report |
02125a82 | 2476 | * @root: root vfsmnt/dentry |
f2eb6575 MS |
2477 | * @buffer: pointer to the end of the buffer |
2478 | * @buflen: pointer to buffer length | |
552ce544 | 2479 | * |
949854d0 | 2480 | * Caller holds the rename_lock. |
1da177e4 | 2481 | */ |
02125a82 AV |
2482 | static int prepend_path(const struct path *path, |
2483 | const struct path *root, | |
f2eb6575 | 2484 | char **buffer, int *buflen) |
1da177e4 | 2485 | { |
9d1bc601 MS |
2486 | struct dentry *dentry = path->dentry; |
2487 | struct vfsmount *vfsmnt = path->mnt; | |
0714a533 | 2488 | struct mount *mnt = real_mount(vfsmnt); |
f2eb6575 MS |
2489 | bool slash = false; |
2490 | int error = 0; | |
6092d048 | 2491 | |
99b7db7b | 2492 | br_read_lock(vfsmount_lock); |
f2eb6575 | 2493 | while (dentry != root->dentry || vfsmnt != root->mnt) { |
1da177e4 LT |
2494 | struct dentry * parent; |
2495 | ||
1da177e4 | 2496 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
552ce544 | 2497 | /* Global root? */ |
676da58d | 2498 | if (!mnt_has_parent(mnt)) |
1da177e4 | 2499 | goto global_root; |
a73324da | 2500 | dentry = mnt->mnt_mountpoint; |
0714a533 AV |
2501 | mnt = mnt->mnt_parent; |
2502 | vfsmnt = &mnt->mnt; | |
1da177e4 LT |
2503 | continue; |
2504 | } | |
2505 | parent = dentry->d_parent; | |
2506 | prefetch(parent); | |
9abca360 | 2507 | spin_lock(&dentry->d_lock); |
f2eb6575 | 2508 | error = prepend_name(buffer, buflen, &dentry->d_name); |
9abca360 | 2509 | spin_unlock(&dentry->d_lock); |
f2eb6575 MS |
2510 | if (!error) |
2511 | error = prepend(buffer, buflen, "/", 1); | |
2512 | if (error) | |
2513 | break; | |
2514 | ||
2515 | slash = true; | |
1da177e4 LT |
2516 | dentry = parent; |
2517 | } | |
2518 | ||
f2eb6575 MS |
2519 | if (!error && !slash) |
2520 | error = prepend(buffer, buflen, "/", 1); | |
2521 | ||
02125a82 | 2522 | out: |
99b7db7b | 2523 | br_read_unlock(vfsmount_lock); |
f2eb6575 | 2524 | return error; |
1da177e4 LT |
2525 | |
2526 | global_root: | |
98dc568b MS |
2527 | /* |
2528 | * Filesystems needing to implement special "root names" | |
2529 | * should do so with ->d_dname() | |
2530 | */ | |
2531 | if (IS_ROOT(dentry) && | |
2532 | (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { | |
2533 | WARN(1, "Root dentry has weird name <%.*s>\n", | |
2534 | (int) dentry->d_name.len, dentry->d_name.name); | |
2535 | } | |
02125a82 AV |
2536 | if (!slash) |
2537 | error = prepend(buffer, buflen, "/", 1); | |
2538 | if (!error) | |
143c8c91 | 2539 | error = real_mount(vfsmnt)->mnt_ns ? 1 : 2; |
be285c71 | 2540 | goto out; |
f2eb6575 | 2541 | } |
be285c71 | 2542 | |
f2eb6575 MS |
2543 | /** |
2544 | * __d_path - return the path of a dentry | |
2545 | * @path: the dentry/vfsmount to report | |
02125a82 | 2546 | * @root: root vfsmnt/dentry |
cd956a1c | 2547 | * @buf: buffer to return value in |
f2eb6575 MS |
2548 | * @buflen: buffer length |
2549 | * | |
ffd1f4ed | 2550 | * Convert a dentry into an ASCII path name. |
f2eb6575 MS |
2551 | * |
2552 | * Returns a pointer into the buffer or an error code if the | |
2553 | * path was too long. | |
2554 | * | |
be148247 | 2555 | * "buflen" should be positive. |
f2eb6575 | 2556 | * |
02125a82 | 2557 | * If the path is not reachable from the supplied root, return %NULL. |
f2eb6575 | 2558 | */ |
02125a82 AV |
2559 | char *__d_path(const struct path *path, |
2560 | const struct path *root, | |
f2eb6575 MS |
2561 | char *buf, int buflen) |
2562 | { | |
2563 | char *res = buf + buflen; | |
2564 | int error; | |
2565 | ||
2566 | prepend(&res, &buflen, "\0", 1); | |
949854d0 | 2567 | write_seqlock(&rename_lock); |
f2eb6575 | 2568 | error = prepend_path(path, root, &res, &buflen); |
949854d0 | 2569 | write_sequnlock(&rename_lock); |
be148247 | 2570 | |
02125a82 AV |
2571 | if (error < 0) |
2572 | return ERR_PTR(error); | |
2573 | if (error > 0) | |
2574 | return NULL; | |
2575 | return res; | |
2576 | } | |
2577 | ||
2578 | char *d_absolute_path(const struct path *path, | |
2579 | char *buf, int buflen) | |
2580 | { | |
2581 | struct path root = {}; | |
2582 | char *res = buf + buflen; | |
2583 | int error; | |
2584 | ||
2585 | prepend(&res, &buflen, "\0", 1); | |
2586 | write_seqlock(&rename_lock); | |
2587 | error = prepend_path(path, &root, &res, &buflen); | |
2588 | write_sequnlock(&rename_lock); | |
2589 | ||
2590 | if (error > 1) | |
2591 | error = -EINVAL; | |
2592 | if (error < 0) | |
f2eb6575 | 2593 | return ERR_PTR(error); |
f2eb6575 | 2594 | return res; |
1da177e4 LT |
2595 | } |
2596 | ||
ffd1f4ed MS |
2597 | /* |
2598 | * same as __d_path but appends "(deleted)" for unlinked files. | |
2599 | */ | |
02125a82 AV |
2600 | static int path_with_deleted(const struct path *path, |
2601 | const struct path *root, | |
2602 | char **buf, int *buflen) | |
ffd1f4ed MS |
2603 | { |
2604 | prepend(buf, buflen, "\0", 1); | |
2605 | if (d_unlinked(path->dentry)) { | |
2606 | int error = prepend(buf, buflen, " (deleted)", 10); | |
2607 | if (error) | |
2608 | return error; | |
2609 | } | |
2610 | ||
2611 | return prepend_path(path, root, buf, buflen); | |
2612 | } | |
2613 | ||
8df9d1a4 MS |
2614 | static int prepend_unreachable(char **buffer, int *buflen) |
2615 | { | |
2616 | return prepend(buffer, buflen, "(unreachable)", 13); | |
2617 | } | |
2618 | ||
a03a8a70 JB |
2619 | /** |
2620 | * d_path - return the path of a dentry | |
cf28b486 | 2621 | * @path: path to report |
a03a8a70 JB |
2622 | * @buf: buffer to return value in |
2623 | * @buflen: buffer length | |
2624 | * | |
2625 | * Convert a dentry into an ASCII path name. If the entry has been deleted | |
2626 | * the string " (deleted)" is appended. Note that this is ambiguous. | |
2627 | * | |
52afeefb AV |
2628 | * Returns a pointer into the buffer or an error code if the path was |
2629 | * too long. Note: Callers should use the returned pointer, not the passed | |
2630 | * in buffer, to use the name! The implementation often starts at an offset | |
2631 | * into the buffer, and may leave 0 bytes at the start. | |
a03a8a70 | 2632 | * |
31f3e0b3 | 2633 | * "buflen" should be positive. |
a03a8a70 | 2634 | */ |
20d4fdc1 | 2635 | char *d_path(const struct path *path, char *buf, int buflen) |
1da177e4 | 2636 | { |
ffd1f4ed | 2637 | char *res = buf + buflen; |
6ac08c39 | 2638 | struct path root; |
ffd1f4ed | 2639 | int error; |
1da177e4 | 2640 | |
c23fbb6b ED |
2641 | /* |
2642 | * We have various synthetic filesystems that never get mounted. On | |
2643 | * these filesystems dentries are never used for lookup purposes, and | |
2644 | * thus don't need to be hashed. They also don't need a name until a | |
2645 | * user wants to identify the object in /proc/pid/fd/. The little hack | |
2646 | * below allows us to generate a name for these objects on demand: | |
2647 | */ | |
cf28b486 JB |
2648 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
2649 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); | |
c23fbb6b | 2650 | |
f7ad3c6b | 2651 | get_fs_root(current->fs, &root); |
949854d0 | 2652 | write_seqlock(&rename_lock); |
02125a82 AV |
2653 | error = path_with_deleted(path, &root, &res, &buflen); |
2654 | if (error < 0) | |
ffd1f4ed | 2655 | res = ERR_PTR(error); |
949854d0 | 2656 | write_sequnlock(&rename_lock); |
6ac08c39 | 2657 | path_put(&root); |
1da177e4 LT |
2658 | return res; |
2659 | } | |
ec4f8605 | 2660 | EXPORT_SYMBOL(d_path); |
1da177e4 | 2661 | |
8df9d1a4 MS |
2662 | /** |
2663 | * d_path_with_unreachable - return the path of a dentry | |
2664 | * @path: path to report | |
2665 | * @buf: buffer to return value in | |
2666 | * @buflen: buffer length | |
2667 | * | |
2668 | * The difference from d_path() is that this prepends "(unreachable)" | |
2669 | * to paths which are unreachable from the current process' root. | |
2670 | */ | |
2671 | char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) | |
2672 | { | |
2673 | char *res = buf + buflen; | |
2674 | struct path root; | |
8df9d1a4 MS |
2675 | int error; |
2676 | ||
2677 | if (path->dentry->d_op && path->dentry->d_op->d_dname) | |
2678 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); | |
2679 | ||
2680 | get_fs_root(current->fs, &root); | |
949854d0 | 2681 | write_seqlock(&rename_lock); |
02125a82 AV |
2682 | error = path_with_deleted(path, &root, &res, &buflen); |
2683 | if (error > 0) | |
8df9d1a4 | 2684 | error = prepend_unreachable(&res, &buflen); |
949854d0 | 2685 | write_sequnlock(&rename_lock); |
8df9d1a4 MS |
2686 | path_put(&root); |
2687 | if (error) | |
2688 | res = ERR_PTR(error); | |
2689 | ||
2690 | return res; | |
2691 | } | |
2692 | ||
c23fbb6b ED |
2693 | /* |
2694 | * Helper function for dentry_operations.d_dname() members | |
2695 | */ | |
2696 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, | |
2697 | const char *fmt, ...) | |
2698 | { | |
2699 | va_list args; | |
2700 | char temp[64]; | |
2701 | int sz; | |
2702 | ||
2703 | va_start(args, fmt); | |
2704 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; | |
2705 | va_end(args); | |
2706 | ||
2707 | if (sz > sizeof(temp) || sz > buflen) | |
2708 | return ERR_PTR(-ENAMETOOLONG); | |
2709 | ||
2710 | buffer += buflen - sz; | |
2711 | return memcpy(buffer, temp, sz); | |
2712 | } | |
2713 | ||
6092d048 RP |
2714 | /* |
2715 | * Write full pathname from the root of the filesystem into the buffer. | |
2716 | */ | |
ec2447c2 | 2717 | static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) |
6092d048 RP |
2718 | { |
2719 | char *end = buf + buflen; | |
2720 | char *retval; | |
2721 | ||
6092d048 | 2722 | prepend(&end, &buflen, "\0", 1); |
6092d048 RP |
2723 | if (buflen < 1) |
2724 | goto Elong; | |
2725 | /* Get '/' right */ | |
2726 | retval = end-1; | |
2727 | *retval = '/'; | |
2728 | ||
cdd16d02 MS |
2729 | while (!IS_ROOT(dentry)) { |
2730 | struct dentry *parent = dentry->d_parent; | |
9abca360 | 2731 | int error; |
6092d048 | 2732 | |
6092d048 | 2733 | prefetch(parent); |
9abca360 NP |
2734 | spin_lock(&dentry->d_lock); |
2735 | error = prepend_name(&end, &buflen, &dentry->d_name); | |
2736 | spin_unlock(&dentry->d_lock); | |
2737 | if (error != 0 || prepend(&end, &buflen, "/", 1) != 0) | |
6092d048 RP |
2738 | goto Elong; |
2739 | ||
2740 | retval = end; | |
2741 | dentry = parent; | |
2742 | } | |
c103135c AV |
2743 | return retval; |
2744 | Elong: | |
2745 | return ERR_PTR(-ENAMETOOLONG); | |
2746 | } | |
ec2447c2 NP |
2747 | |
2748 | char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) | |
2749 | { | |
2750 | char *retval; | |
2751 | ||
949854d0 | 2752 | write_seqlock(&rename_lock); |
ec2447c2 | 2753 | retval = __dentry_path(dentry, buf, buflen); |
949854d0 | 2754 | write_sequnlock(&rename_lock); |
ec2447c2 NP |
2755 | |
2756 | return retval; | |
2757 | } | |
2758 | EXPORT_SYMBOL(dentry_path_raw); | |
c103135c AV |
2759 | |
2760 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) | |
2761 | { | |
2762 | char *p = NULL; | |
2763 | char *retval; | |
2764 | ||
949854d0 | 2765 | write_seqlock(&rename_lock); |
c103135c AV |
2766 | if (d_unlinked(dentry)) { |
2767 | p = buf + buflen; | |
2768 | if (prepend(&p, &buflen, "//deleted", 10) != 0) | |
2769 | goto Elong; | |
2770 | buflen++; | |
2771 | } | |
2772 | retval = __dentry_path(dentry, buf, buflen); | |
949854d0 | 2773 | write_sequnlock(&rename_lock); |
c103135c AV |
2774 | if (!IS_ERR(retval) && p) |
2775 | *p = '/'; /* restore '/' overriden with '\0' */ | |
6092d048 RP |
2776 | return retval; |
2777 | Elong: | |
6092d048 RP |
2778 | return ERR_PTR(-ENAMETOOLONG); |
2779 | } | |
2780 | ||
1da177e4 LT |
2781 | /* |
2782 | * NOTE! The user-level library version returns a | |
2783 | * character pointer. The kernel system call just | |
2784 | * returns the length of the buffer filled (which | |
2785 | * includes the ending '\0' character), or a negative | |
2786 | * error value. So libc would do something like | |
2787 | * | |
2788 | * char *getcwd(char * buf, size_t size) | |
2789 | * { | |
2790 | * int retval; | |
2791 | * | |
2792 | * retval = sys_getcwd(buf, size); | |
2793 | * if (retval >= 0) | |
2794 | * return buf; | |
2795 | * errno = -retval; | |
2796 | * return NULL; | |
2797 | * } | |
2798 | */ | |
3cdad428 | 2799 | SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) |
1da177e4 | 2800 | { |
552ce544 | 2801 | int error; |
6ac08c39 | 2802 | struct path pwd, root; |
552ce544 | 2803 | char *page = (char *) __get_free_page(GFP_USER); |
1da177e4 LT |
2804 | |
2805 | if (!page) | |
2806 | return -ENOMEM; | |
2807 | ||
f7ad3c6b | 2808 | get_fs_root_and_pwd(current->fs, &root, &pwd); |
1da177e4 | 2809 | |
552ce544 | 2810 | error = -ENOENT; |
949854d0 | 2811 | write_seqlock(&rename_lock); |
f3da392e | 2812 | if (!d_unlinked(pwd.dentry)) { |
552ce544 | 2813 | unsigned long len; |
8df9d1a4 MS |
2814 | char *cwd = page + PAGE_SIZE; |
2815 | int buflen = PAGE_SIZE; | |
1da177e4 | 2816 | |
8df9d1a4 | 2817 | prepend(&cwd, &buflen, "\0", 1); |
02125a82 | 2818 | error = prepend_path(&pwd, &root, &cwd, &buflen); |
949854d0 | 2819 | write_sequnlock(&rename_lock); |
552ce544 | 2820 | |
02125a82 | 2821 | if (error < 0) |
552ce544 LT |
2822 | goto out; |
2823 | ||
8df9d1a4 | 2824 | /* Unreachable from current root */ |
02125a82 | 2825 | if (error > 0) { |
8df9d1a4 MS |
2826 | error = prepend_unreachable(&cwd, &buflen); |
2827 | if (error) | |
2828 | goto out; | |
2829 | } | |
2830 | ||
552ce544 LT |
2831 | error = -ERANGE; |
2832 | len = PAGE_SIZE + page - cwd; | |
2833 | if (len <= size) { | |
2834 | error = len; | |
2835 | if (copy_to_user(buf, cwd, len)) | |
2836 | error = -EFAULT; | |
2837 | } | |
949854d0 NP |
2838 | } else { |
2839 | write_sequnlock(&rename_lock); | |
949854d0 | 2840 | } |
1da177e4 LT |
2841 | |
2842 | out: | |
6ac08c39 JB |
2843 | path_put(&pwd); |
2844 | path_put(&root); | |
1da177e4 LT |
2845 | free_page((unsigned long) page); |
2846 | return error; | |
2847 | } | |
2848 | ||
2849 | /* | |
2850 | * Test whether new_dentry is a subdirectory of old_dentry. | |
2851 | * | |
2852 | * Trivially implemented using the dcache structure | |
2853 | */ | |
2854 | ||
2855 | /** | |
2856 | * is_subdir - is new dentry a subdirectory of old_dentry | |
2857 | * @new_dentry: new dentry | |
2858 | * @old_dentry: old dentry | |
2859 | * | |
2860 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). | |
2861 | * Returns 0 otherwise. | |
2862 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() | |
2863 | */ | |
2864 | ||
e2761a11 | 2865 | int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) |
1da177e4 LT |
2866 | { |
2867 | int result; | |
949854d0 | 2868 | unsigned seq; |
1da177e4 | 2869 | |
e2761a11 OH |
2870 | if (new_dentry == old_dentry) |
2871 | return 1; | |
2872 | ||
e2761a11 | 2873 | do { |
1da177e4 | 2874 | /* for restarting inner loop in case of seq retry */ |
1da177e4 | 2875 | seq = read_seqbegin(&rename_lock); |
949854d0 NP |
2876 | /* |
2877 | * Need rcu_readlock to protect against the d_parent trashing | |
2878 | * due to d_move | |
2879 | */ | |
2880 | rcu_read_lock(); | |
e2761a11 | 2881 | if (d_ancestor(old_dentry, new_dentry)) |
1da177e4 | 2882 | result = 1; |
e2761a11 OH |
2883 | else |
2884 | result = 0; | |
949854d0 | 2885 | rcu_read_unlock(); |
1da177e4 | 2886 | } while (read_seqretry(&rename_lock, seq)); |
1da177e4 LT |
2887 | |
2888 | return result; | |
2889 | } | |
2890 | ||
2891 | void d_genocide(struct dentry *root) | |
2892 | { | |
949854d0 | 2893 | struct dentry *this_parent; |
1da177e4 | 2894 | struct list_head *next; |
949854d0 | 2895 | unsigned seq; |
58db63d0 | 2896 | int locked = 0; |
1da177e4 | 2897 | |
949854d0 | 2898 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
2899 | again: |
2900 | this_parent = root; | |
2fd6b7f5 | 2901 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
2902 | repeat: |
2903 | next = this_parent->d_subdirs.next; | |
2904 | resume: | |
2905 | while (next != &this_parent->d_subdirs) { | |
2906 | struct list_head *tmp = next; | |
5160ee6f | 2907 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 | 2908 | next = tmp->next; |
949854d0 | 2909 | |
da502956 NP |
2910 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
2911 | if (d_unhashed(dentry) || !dentry->d_inode) { | |
2912 | spin_unlock(&dentry->d_lock); | |
1da177e4 | 2913 | continue; |
da502956 | 2914 | } |
1da177e4 | 2915 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
2916 | spin_unlock(&this_parent->d_lock); |
2917 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 2918 | this_parent = dentry; |
2fd6b7f5 | 2919 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
2920 | goto repeat; |
2921 | } | |
949854d0 NP |
2922 | if (!(dentry->d_flags & DCACHE_GENOCIDE)) { |
2923 | dentry->d_flags |= DCACHE_GENOCIDE; | |
2924 | dentry->d_count--; | |
2925 | } | |
b7ab39f6 | 2926 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
2927 | } |
2928 | if (this_parent != root) { | |
c826cb7d | 2929 | struct dentry *child = this_parent; |
949854d0 NP |
2930 | if (!(this_parent->d_flags & DCACHE_GENOCIDE)) { |
2931 | this_parent->d_flags |= DCACHE_GENOCIDE; | |
2932 | this_parent->d_count--; | |
2933 | } | |
c826cb7d LT |
2934 | this_parent = try_to_ascend(this_parent, locked, seq); |
2935 | if (!this_parent) | |
949854d0 | 2936 | goto rename_retry; |
949854d0 | 2937 | next = child->d_u.d_child.next; |
1da177e4 LT |
2938 | goto resume; |
2939 | } | |
2fd6b7f5 | 2940 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 2941 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 2942 | goto rename_retry; |
58db63d0 NP |
2943 | if (locked) |
2944 | write_sequnlock(&rename_lock); | |
2945 | return; | |
2946 | ||
2947 | rename_retry: | |
2948 | locked = 1; | |
2949 | write_seqlock(&rename_lock); | |
2950 | goto again; | |
1da177e4 LT |
2951 | } |
2952 | ||
2953 | /** | |
2954 | * find_inode_number - check for dentry with name | |
2955 | * @dir: directory to check | |
2956 | * @name: Name to find. | |
2957 | * | |
2958 | * Check whether a dentry already exists for the given name, | |
2959 | * and return the inode number if it has an inode. Otherwise | |
2960 | * 0 is returned. | |
2961 | * | |
2962 | * This routine is used to post-process directory listings for | |
2963 | * filesystems using synthetic inode numbers, and is necessary | |
2964 | * to keep getcwd() working. | |
2965 | */ | |
2966 | ||
2967 | ino_t find_inode_number(struct dentry *dir, struct qstr *name) | |
2968 | { | |
2969 | struct dentry * dentry; | |
2970 | ino_t ino = 0; | |
2971 | ||
3e7e241f EB |
2972 | dentry = d_hash_and_lookup(dir, name); |
2973 | if (dentry) { | |
1da177e4 LT |
2974 | if (dentry->d_inode) |
2975 | ino = dentry->d_inode->i_ino; | |
2976 | dput(dentry); | |
2977 | } | |
1da177e4 LT |
2978 | return ino; |
2979 | } | |
ec4f8605 | 2980 | EXPORT_SYMBOL(find_inode_number); |
1da177e4 LT |
2981 | |
2982 | static __initdata unsigned long dhash_entries; | |
2983 | static int __init set_dhash_entries(char *str) | |
2984 | { | |
2985 | if (!str) | |
2986 | return 0; | |
2987 | dhash_entries = simple_strtoul(str, &str, 0); | |
2988 | return 1; | |
2989 | } | |
2990 | __setup("dhash_entries=", set_dhash_entries); | |
2991 | ||
2992 | static void __init dcache_init_early(void) | |
2993 | { | |
074b8517 | 2994 | unsigned int loop; |
1da177e4 LT |
2995 | |
2996 | /* If hashes are distributed across NUMA nodes, defer | |
2997 | * hash allocation until vmalloc space is available. | |
2998 | */ | |
2999 | if (hashdist) | |
3000 | return; | |
3001 | ||
3002 | dentry_hashtable = | |
3003 | alloc_large_system_hash("Dentry cache", | |
b07ad996 | 3004 | sizeof(struct hlist_bl_head), |
1da177e4 LT |
3005 | dhash_entries, |
3006 | 13, | |
3007 | HASH_EARLY, | |
3008 | &d_hash_shift, | |
3009 | &d_hash_mask, | |
3010 | 0); | |
3011 | ||
074b8517 | 3012 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
b07ad996 | 3013 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
1da177e4 LT |
3014 | } |
3015 | ||
74bf17cf | 3016 | static void __init dcache_init(void) |
1da177e4 | 3017 | { |
074b8517 | 3018 | unsigned int loop; |
1da177e4 LT |
3019 | |
3020 | /* | |
3021 | * A constructor could be added for stable state like the lists, | |
3022 | * but it is probably not worth it because of the cache nature | |
3023 | * of the dcache. | |
3024 | */ | |
0a31bd5f CL |
3025 | dentry_cache = KMEM_CACHE(dentry, |
3026 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); | |
1da177e4 LT |
3027 | |
3028 | /* Hash may have been set up in dcache_init_early */ | |
3029 | if (!hashdist) | |
3030 | return; | |
3031 | ||
3032 | dentry_hashtable = | |
3033 | alloc_large_system_hash("Dentry cache", | |
b07ad996 | 3034 | sizeof(struct hlist_bl_head), |
1da177e4 LT |
3035 | dhash_entries, |
3036 | 13, | |
3037 | 0, | |
3038 | &d_hash_shift, | |
3039 | &d_hash_mask, | |
3040 | 0); | |
3041 | ||
074b8517 | 3042 | for (loop = 0; loop < (1U << d_hash_shift); loop++) |
b07ad996 | 3043 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
1da177e4 LT |
3044 | } |
3045 | ||
3046 | /* SLAB cache for __getname() consumers */ | |
e18b890b | 3047 | struct kmem_cache *names_cachep __read_mostly; |
ec4f8605 | 3048 | EXPORT_SYMBOL(names_cachep); |
1da177e4 | 3049 | |
1da177e4 LT |
3050 | EXPORT_SYMBOL(d_genocide); |
3051 | ||
1da177e4 LT |
3052 | void __init vfs_caches_init_early(void) |
3053 | { | |
3054 | dcache_init_early(); | |
3055 | inode_init_early(); | |
3056 | } | |
3057 | ||
3058 | void __init vfs_caches_init(unsigned long mempages) | |
3059 | { | |
3060 | unsigned long reserve; | |
3061 | ||
3062 | /* Base hash sizes on available memory, with a reserve equal to | |
3063 | 150% of current kernel size */ | |
3064 | ||
3065 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); | |
3066 | mempages -= reserve; | |
3067 | ||
3068 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, | |
20c2df83 | 3069 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 3070 | |
74bf17cf DC |
3071 | dcache_init(); |
3072 | inode_init(); | |
1da177e4 | 3073 | files_init(mempages); |
74bf17cf | 3074 | mnt_init(); |
1da177e4 LT |
3075 | bdev_cache_init(); |
3076 | chrdev_init(); | |
3077 | } |