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Commit | Line | Data |
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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 | |
b07ad996 | 107 | static inline struct hlist_bl_head *d_hash(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 | ||
9c82ab9c | 140 | static void __d_free(struct rcu_head *head) |
1da177e4 | 141 | { |
9c82ab9c CH |
142 | struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); |
143 | ||
fd217f4d | 144 | WARN_ON(!list_empty(&dentry->d_alias)); |
1da177e4 LT |
145 | if (dname_external(dentry)) |
146 | kfree(dentry->d_name.name); | |
147 | kmem_cache_free(dentry_cache, dentry); | |
148 | } | |
149 | ||
150 | /* | |
b5c84bf6 | 151 | * no locks, please. |
1da177e4 LT |
152 | */ |
153 | static void d_free(struct dentry *dentry) | |
154 | { | |
b7ab39f6 | 155 | BUG_ON(dentry->d_count); |
3e880fb5 | 156 | this_cpu_dec(nr_dentry); |
1da177e4 LT |
157 | if (dentry->d_op && dentry->d_op->d_release) |
158 | dentry->d_op->d_release(dentry); | |
312d3ca8 | 159 | |
dea3667b LT |
160 | /* if dentry was never visible to RCU, immediate free is OK */ |
161 | if (!(dentry->d_flags & DCACHE_RCUACCESS)) | |
9c82ab9c | 162 | __d_free(&dentry->d_u.d_rcu); |
b3423415 | 163 | else |
9c82ab9c | 164 | call_rcu(&dentry->d_u.d_rcu, __d_free); |
1da177e4 LT |
165 | } |
166 | ||
31e6b01f NP |
167 | /** |
168 | * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups | |
ff5fdb61 | 169 | * @dentry: the target dentry |
31e6b01f NP |
170 | * After this call, in-progress rcu-walk path lookup will fail. This |
171 | * should be called after unhashing, and after changing d_inode (if | |
172 | * the dentry has not already been unhashed). | |
173 | */ | |
174 | static inline void dentry_rcuwalk_barrier(struct dentry *dentry) | |
175 | { | |
176 | assert_spin_locked(&dentry->d_lock); | |
177 | /* Go through a barrier */ | |
178 | write_seqcount_barrier(&dentry->d_seq); | |
179 | } | |
180 | ||
1da177e4 LT |
181 | /* |
182 | * Release the dentry's inode, using the filesystem | |
31e6b01f NP |
183 | * d_iput() operation if defined. Dentry has no refcount |
184 | * and is unhashed. | |
1da177e4 | 185 | */ |
858119e1 | 186 | static void dentry_iput(struct dentry * dentry) |
31f3e0b3 | 187 | __releases(dentry->d_lock) |
873feea0 | 188 | __releases(dentry->d_inode->i_lock) |
1da177e4 LT |
189 | { |
190 | struct inode *inode = dentry->d_inode; | |
191 | if (inode) { | |
192 | dentry->d_inode = NULL; | |
193 | list_del_init(&dentry->d_alias); | |
194 | spin_unlock(&dentry->d_lock); | |
873feea0 | 195 | spin_unlock(&inode->i_lock); |
f805fbda LT |
196 | if (!inode->i_nlink) |
197 | fsnotify_inoderemove(inode); | |
1da177e4 LT |
198 | if (dentry->d_op && dentry->d_op->d_iput) |
199 | dentry->d_op->d_iput(dentry, inode); | |
200 | else | |
201 | iput(inode); | |
202 | } else { | |
203 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
204 | } |
205 | } | |
206 | ||
31e6b01f NP |
207 | /* |
208 | * Release the dentry's inode, using the filesystem | |
209 | * d_iput() operation if defined. dentry remains in-use. | |
210 | */ | |
211 | static void dentry_unlink_inode(struct dentry * dentry) | |
212 | __releases(dentry->d_lock) | |
873feea0 | 213 | __releases(dentry->d_inode->i_lock) |
31e6b01f NP |
214 | { |
215 | struct inode *inode = dentry->d_inode; | |
216 | dentry->d_inode = NULL; | |
217 | list_del_init(&dentry->d_alias); | |
218 | dentry_rcuwalk_barrier(dentry); | |
219 | spin_unlock(&dentry->d_lock); | |
873feea0 | 220 | spin_unlock(&inode->i_lock); |
31e6b01f NP |
221 | if (!inode->i_nlink) |
222 | fsnotify_inoderemove(inode); | |
223 | if (dentry->d_op && dentry->d_op->d_iput) | |
224 | dentry->d_op->d_iput(dentry, inode); | |
225 | else | |
226 | iput(inode); | |
227 | } | |
228 | ||
da3bbdd4 | 229 | /* |
f0023bc6 | 230 | * dentry_lru_(add|del|prune|move_tail) must be called with d_lock held. |
da3bbdd4 KM |
231 | */ |
232 | static void dentry_lru_add(struct dentry *dentry) | |
233 | { | |
a4633357 | 234 | if (list_empty(&dentry->d_lru)) { |
23044507 | 235 | spin_lock(&dcache_lru_lock); |
a4633357 CH |
236 | list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); |
237 | dentry->d_sb->s_nr_dentry_unused++; | |
86c8749e | 238 | dentry_stat.nr_unused++; |
23044507 | 239 | spin_unlock(&dcache_lru_lock); |
a4633357 | 240 | } |
da3bbdd4 KM |
241 | } |
242 | ||
23044507 NP |
243 | static void __dentry_lru_del(struct dentry *dentry) |
244 | { | |
245 | list_del_init(&dentry->d_lru); | |
246 | dentry->d_sb->s_nr_dentry_unused--; | |
247 | dentry_stat.nr_unused--; | |
248 | } | |
249 | ||
f0023bc6 SW |
250 | /* |
251 | * Remove a dentry with references from the LRU. | |
252 | */ | |
da3bbdd4 KM |
253 | static void dentry_lru_del(struct dentry *dentry) |
254 | { | |
255 | if (!list_empty(&dentry->d_lru)) { | |
23044507 NP |
256 | spin_lock(&dcache_lru_lock); |
257 | __dentry_lru_del(dentry); | |
258 | spin_unlock(&dcache_lru_lock); | |
da3bbdd4 KM |
259 | } |
260 | } | |
261 | ||
f0023bc6 SW |
262 | /* |
263 | * Remove a dentry that is unreferenced and about to be pruned | |
264 | * (unhashed and destroyed) from the LRU, and inform the file system. | |
265 | * This wrapper should be called _prior_ to unhashing a victim dentry. | |
266 | */ | |
267 | static void dentry_lru_prune(struct dentry *dentry) | |
268 | { | |
269 | if (!list_empty(&dentry->d_lru)) { | |
270 | if (dentry->d_flags & DCACHE_OP_PRUNE) | |
271 | dentry->d_op->d_prune(dentry); | |
272 | ||
273 | spin_lock(&dcache_lru_lock); | |
274 | __dentry_lru_del(dentry); | |
275 | spin_unlock(&dcache_lru_lock); | |
276 | } | |
277 | } | |
278 | ||
a4633357 | 279 | static void dentry_lru_move_tail(struct dentry *dentry) |
da3bbdd4 | 280 | { |
23044507 | 281 | spin_lock(&dcache_lru_lock); |
a4633357 CH |
282 | if (list_empty(&dentry->d_lru)) { |
283 | list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); | |
284 | dentry->d_sb->s_nr_dentry_unused++; | |
86c8749e | 285 | dentry_stat.nr_unused++; |
a4633357 CH |
286 | } else { |
287 | list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru); | |
da3bbdd4 | 288 | } |
23044507 | 289 | spin_unlock(&dcache_lru_lock); |
da3bbdd4 KM |
290 | } |
291 | ||
d52b9086 MS |
292 | /** |
293 | * d_kill - kill dentry and return parent | |
294 | * @dentry: dentry to kill | |
ff5fdb61 | 295 | * @parent: parent dentry |
d52b9086 | 296 | * |
31f3e0b3 | 297 | * The dentry must already be unhashed and removed from the LRU. |
d52b9086 MS |
298 | * |
299 | * If this is the root of the dentry tree, return NULL. | |
23044507 | 300 | * |
b5c84bf6 NP |
301 | * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by |
302 | * d_kill. | |
d52b9086 | 303 | */ |
2fd6b7f5 | 304 | static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) |
31f3e0b3 | 305 | __releases(dentry->d_lock) |
2fd6b7f5 | 306 | __releases(parent->d_lock) |
873feea0 | 307 | __releases(dentry->d_inode->i_lock) |
d52b9086 | 308 | { |
d52b9086 | 309 | list_del(&dentry->d_u.d_child); |
c83ce989 TM |
310 | /* |
311 | * Inform try_to_ascend() that we are no longer attached to the | |
312 | * dentry tree | |
313 | */ | |
314 | dentry->d_flags |= DCACHE_DISCONNECTED; | |
2fd6b7f5 NP |
315 | if (parent) |
316 | spin_unlock(&parent->d_lock); | |
d52b9086 | 317 | dentry_iput(dentry); |
b7ab39f6 NP |
318 | /* |
319 | * dentry_iput drops the locks, at which point nobody (except | |
320 | * transient RCU lookups) can reach this dentry. | |
321 | */ | |
d52b9086 | 322 | d_free(dentry); |
871c0067 | 323 | return parent; |
d52b9086 MS |
324 | } |
325 | ||
c6627c60 DH |
326 | /* |
327 | * Unhash a dentry without inserting an RCU walk barrier or checking that | |
328 | * dentry->d_lock is locked. The caller must take care of that, if | |
329 | * appropriate. | |
330 | */ | |
331 | static void __d_shrink(struct dentry *dentry) | |
332 | { | |
333 | if (!d_unhashed(dentry)) { | |
334 | struct hlist_bl_head *b; | |
335 | if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) | |
336 | b = &dentry->d_sb->s_anon; | |
337 | else | |
338 | b = d_hash(dentry->d_parent, dentry->d_name.hash); | |
339 | ||
340 | hlist_bl_lock(b); | |
341 | __hlist_bl_del(&dentry->d_hash); | |
342 | dentry->d_hash.pprev = NULL; | |
343 | hlist_bl_unlock(b); | |
344 | } | |
345 | } | |
346 | ||
789680d1 NP |
347 | /** |
348 | * d_drop - drop a dentry | |
349 | * @dentry: dentry to drop | |
350 | * | |
351 | * d_drop() unhashes the entry from the parent dentry hashes, so that it won't | |
352 | * be found through a VFS lookup any more. Note that this is different from | |
353 | * deleting the dentry - d_delete will try to mark the dentry negative if | |
354 | * possible, giving a successful _negative_ lookup, while d_drop will | |
355 | * just make the cache lookup fail. | |
356 | * | |
357 | * d_drop() is used mainly for stuff that wants to invalidate a dentry for some | |
358 | * reason (NFS timeouts or autofs deletes). | |
359 | * | |
360 | * __d_drop requires dentry->d_lock. | |
361 | */ | |
362 | void __d_drop(struct dentry *dentry) | |
363 | { | |
dea3667b | 364 | if (!d_unhashed(dentry)) { |
c6627c60 | 365 | __d_shrink(dentry); |
dea3667b | 366 | dentry_rcuwalk_barrier(dentry); |
789680d1 NP |
367 | } |
368 | } | |
369 | EXPORT_SYMBOL(__d_drop); | |
370 | ||
371 | void d_drop(struct dentry *dentry) | |
372 | { | |
789680d1 NP |
373 | spin_lock(&dentry->d_lock); |
374 | __d_drop(dentry); | |
375 | spin_unlock(&dentry->d_lock); | |
789680d1 NP |
376 | } |
377 | EXPORT_SYMBOL(d_drop); | |
378 | ||
44396f4b JB |
379 | /* |
380 | * d_clear_need_lookup - drop a dentry from cache and clear the need lookup flag | |
381 | * @dentry: dentry to drop | |
382 | * | |
383 | * This is called when we do a lookup on a placeholder dentry that needed to be | |
384 | * looked up. The dentry should have been hashed in order for it to be found by | |
385 | * the lookup code, but now needs to be unhashed while we do the actual lookup | |
386 | * and clear the DCACHE_NEED_LOOKUP flag. | |
387 | */ | |
388 | void d_clear_need_lookup(struct dentry *dentry) | |
389 | { | |
390 | spin_lock(&dentry->d_lock); | |
391 | __d_drop(dentry); | |
392 | dentry->d_flags &= ~DCACHE_NEED_LOOKUP; | |
393 | spin_unlock(&dentry->d_lock); | |
394 | } | |
395 | EXPORT_SYMBOL(d_clear_need_lookup); | |
396 | ||
77812a1e NP |
397 | /* |
398 | * Finish off a dentry we've decided to kill. | |
399 | * dentry->d_lock must be held, returns with it unlocked. | |
400 | * If ref is non-zero, then decrement the refcount too. | |
401 | * Returns dentry requiring refcount drop, or NULL if we're done. | |
402 | */ | |
403 | static inline struct dentry *dentry_kill(struct dentry *dentry, int ref) | |
404 | __releases(dentry->d_lock) | |
405 | { | |
873feea0 | 406 | struct inode *inode; |
77812a1e NP |
407 | struct dentry *parent; |
408 | ||
873feea0 NP |
409 | inode = dentry->d_inode; |
410 | if (inode && !spin_trylock(&inode->i_lock)) { | |
77812a1e NP |
411 | relock: |
412 | spin_unlock(&dentry->d_lock); | |
413 | cpu_relax(); | |
414 | return dentry; /* try again with same dentry */ | |
415 | } | |
416 | if (IS_ROOT(dentry)) | |
417 | parent = NULL; | |
418 | else | |
419 | parent = dentry->d_parent; | |
420 | if (parent && !spin_trylock(&parent->d_lock)) { | |
873feea0 NP |
421 | if (inode) |
422 | spin_unlock(&inode->i_lock); | |
77812a1e NP |
423 | goto relock; |
424 | } | |
31e6b01f | 425 | |
77812a1e NP |
426 | if (ref) |
427 | dentry->d_count--; | |
f0023bc6 SW |
428 | /* |
429 | * if dentry was on the d_lru list delete it from there. | |
430 | * inform the fs via d_prune that this dentry is about to be | |
431 | * unhashed and destroyed. | |
432 | */ | |
433 | dentry_lru_prune(dentry); | |
77812a1e NP |
434 | /* if it was on the hash then remove it */ |
435 | __d_drop(dentry); | |
436 | return d_kill(dentry, parent); | |
437 | } | |
438 | ||
1da177e4 LT |
439 | /* |
440 | * This is dput | |
441 | * | |
442 | * This is complicated by the fact that we do not want to put | |
443 | * dentries that are no longer on any hash chain on the unused | |
444 | * list: we'd much rather just get rid of them immediately. | |
445 | * | |
446 | * However, that implies that we have to traverse the dentry | |
447 | * tree upwards to the parents which might _also_ now be | |
448 | * scheduled for deletion (it may have been only waiting for | |
449 | * its last child to go away). | |
450 | * | |
451 | * This tail recursion is done by hand as we don't want to depend | |
452 | * on the compiler to always get this right (gcc generally doesn't). | |
453 | * Real recursion would eat up our stack space. | |
454 | */ | |
455 | ||
456 | /* | |
457 | * dput - release a dentry | |
458 | * @dentry: dentry to release | |
459 | * | |
460 | * Release a dentry. This will drop the usage count and if appropriate | |
461 | * call the dentry unlink method as well as removing it from the queues and | |
462 | * releasing its resources. If the parent dentries were scheduled for release | |
463 | * they too may now get deleted. | |
1da177e4 | 464 | */ |
1da177e4 LT |
465 | void dput(struct dentry *dentry) |
466 | { | |
467 | if (!dentry) | |
468 | return; | |
469 | ||
470 | repeat: | |
b7ab39f6 | 471 | if (dentry->d_count == 1) |
1da177e4 | 472 | might_sleep(); |
1da177e4 | 473 | spin_lock(&dentry->d_lock); |
61f3dee4 NP |
474 | BUG_ON(!dentry->d_count); |
475 | if (dentry->d_count > 1) { | |
476 | dentry->d_count--; | |
1da177e4 | 477 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
478 | return; |
479 | } | |
480 | ||
fb045adb | 481 | if (dentry->d_flags & DCACHE_OP_DELETE) { |
1da177e4 | 482 | if (dentry->d_op->d_delete(dentry)) |
61f3dee4 | 483 | goto kill_it; |
1da177e4 | 484 | } |
265ac902 | 485 | |
1da177e4 LT |
486 | /* Unreachable? Get rid of it */ |
487 | if (d_unhashed(dentry)) | |
488 | goto kill_it; | |
265ac902 | 489 | |
44396f4b JB |
490 | /* |
491 | * If this dentry needs lookup, don't set the referenced flag so that it | |
492 | * is more likely to be cleaned up by the dcache shrinker in case of | |
493 | * memory pressure. | |
494 | */ | |
495 | if (!d_need_lookup(dentry)) | |
496 | dentry->d_flags |= DCACHE_REFERENCED; | |
a4633357 | 497 | dentry_lru_add(dentry); |
265ac902 | 498 | |
61f3dee4 NP |
499 | dentry->d_count--; |
500 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
501 | return; |
502 | ||
d52b9086 | 503 | kill_it: |
77812a1e | 504 | dentry = dentry_kill(dentry, 1); |
d52b9086 MS |
505 | if (dentry) |
506 | goto repeat; | |
1da177e4 | 507 | } |
ec4f8605 | 508 | EXPORT_SYMBOL(dput); |
1da177e4 LT |
509 | |
510 | /** | |
511 | * d_invalidate - invalidate a dentry | |
512 | * @dentry: dentry to invalidate | |
513 | * | |
514 | * Try to invalidate the dentry if it turns out to be | |
515 | * possible. If there are other dentries that can be | |
516 | * reached through this one we can't delete it and we | |
517 | * return -EBUSY. On success we return 0. | |
518 | * | |
519 | * no dcache lock. | |
520 | */ | |
521 | ||
522 | int d_invalidate(struct dentry * dentry) | |
523 | { | |
524 | /* | |
525 | * If it's already been dropped, return OK. | |
526 | */ | |
da502956 | 527 | spin_lock(&dentry->d_lock); |
1da177e4 | 528 | if (d_unhashed(dentry)) { |
da502956 | 529 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
530 | return 0; |
531 | } | |
532 | /* | |
533 | * Check whether to do a partial shrink_dcache | |
534 | * to get rid of unused child entries. | |
535 | */ | |
536 | if (!list_empty(&dentry->d_subdirs)) { | |
da502956 | 537 | spin_unlock(&dentry->d_lock); |
1da177e4 | 538 | shrink_dcache_parent(dentry); |
da502956 | 539 | spin_lock(&dentry->d_lock); |
1da177e4 LT |
540 | } |
541 | ||
542 | /* | |
543 | * Somebody else still using it? | |
544 | * | |
545 | * If it's a directory, we can't drop it | |
546 | * for fear of somebody re-populating it | |
547 | * with children (even though dropping it | |
548 | * would make it unreachable from the root, | |
549 | * we might still populate it if it was a | |
550 | * working directory or similar). | |
50e69630 AV |
551 | * We also need to leave mountpoints alone, |
552 | * directory or not. | |
1da177e4 | 553 | */ |
50e69630 AV |
554 | if (dentry->d_count > 1 && dentry->d_inode) { |
555 | if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) { | |
1da177e4 | 556 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
557 | return -EBUSY; |
558 | } | |
559 | } | |
560 | ||
561 | __d_drop(dentry); | |
562 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
563 | return 0; |
564 | } | |
ec4f8605 | 565 | EXPORT_SYMBOL(d_invalidate); |
1da177e4 | 566 | |
b5c84bf6 | 567 | /* This must be called with d_lock held */ |
dc0474be | 568 | static inline void __dget_dlock(struct dentry *dentry) |
23044507 | 569 | { |
b7ab39f6 | 570 | dentry->d_count++; |
23044507 NP |
571 | } |
572 | ||
dc0474be | 573 | static inline void __dget(struct dentry *dentry) |
1da177e4 | 574 | { |
23044507 | 575 | spin_lock(&dentry->d_lock); |
dc0474be | 576 | __dget_dlock(dentry); |
23044507 | 577 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
578 | } |
579 | ||
b7ab39f6 NP |
580 | struct dentry *dget_parent(struct dentry *dentry) |
581 | { | |
582 | struct dentry *ret; | |
583 | ||
584 | repeat: | |
a734eb45 NP |
585 | /* |
586 | * Don't need rcu_dereference because we re-check it was correct under | |
587 | * the lock. | |
588 | */ | |
589 | rcu_read_lock(); | |
b7ab39f6 | 590 | ret = dentry->d_parent; |
a734eb45 NP |
591 | spin_lock(&ret->d_lock); |
592 | if (unlikely(ret != dentry->d_parent)) { | |
593 | spin_unlock(&ret->d_lock); | |
594 | rcu_read_unlock(); | |
b7ab39f6 NP |
595 | goto repeat; |
596 | } | |
a734eb45 | 597 | rcu_read_unlock(); |
b7ab39f6 NP |
598 | BUG_ON(!ret->d_count); |
599 | ret->d_count++; | |
600 | spin_unlock(&ret->d_lock); | |
b7ab39f6 NP |
601 | return ret; |
602 | } | |
603 | EXPORT_SYMBOL(dget_parent); | |
604 | ||
1da177e4 LT |
605 | /** |
606 | * d_find_alias - grab a hashed alias of inode | |
607 | * @inode: inode in question | |
608 | * @want_discon: flag, used by d_splice_alias, to request | |
609 | * that only a DISCONNECTED alias be returned. | |
610 | * | |
611 | * If inode has a hashed alias, or is a directory and has any alias, | |
612 | * acquire the reference to alias and return it. Otherwise return NULL. | |
613 | * Notice that if inode is a directory there can be only one alias and | |
614 | * it can be unhashed only if it has no children, or if it is the root | |
615 | * of a filesystem. | |
616 | * | |
21c0d8fd | 617 | * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer |
1da177e4 | 618 | * any other hashed alias over that one unless @want_discon is set, |
21c0d8fd | 619 | * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias. |
1da177e4 | 620 | */ |
da502956 | 621 | static struct dentry *__d_find_alias(struct inode *inode, int want_discon) |
1da177e4 | 622 | { |
da502956 | 623 | struct dentry *alias, *discon_alias; |
1da177e4 | 624 | |
da502956 NP |
625 | again: |
626 | discon_alias = NULL; | |
627 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { | |
628 | spin_lock(&alias->d_lock); | |
1da177e4 | 629 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { |
21c0d8fd | 630 | if (IS_ROOT(alias) && |
da502956 | 631 | (alias->d_flags & DCACHE_DISCONNECTED)) { |
1da177e4 | 632 | discon_alias = alias; |
da502956 | 633 | } else if (!want_discon) { |
dc0474be | 634 | __dget_dlock(alias); |
da502956 NP |
635 | spin_unlock(&alias->d_lock); |
636 | return alias; | |
637 | } | |
638 | } | |
639 | spin_unlock(&alias->d_lock); | |
640 | } | |
641 | if (discon_alias) { | |
642 | alias = discon_alias; | |
643 | spin_lock(&alias->d_lock); | |
644 | if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { | |
645 | if (IS_ROOT(alias) && | |
646 | (alias->d_flags & DCACHE_DISCONNECTED)) { | |
dc0474be | 647 | __dget_dlock(alias); |
da502956 | 648 | spin_unlock(&alias->d_lock); |
1da177e4 LT |
649 | return alias; |
650 | } | |
651 | } | |
da502956 NP |
652 | spin_unlock(&alias->d_lock); |
653 | goto again; | |
1da177e4 | 654 | } |
da502956 | 655 | return NULL; |
1da177e4 LT |
656 | } |
657 | ||
da502956 | 658 | struct dentry *d_find_alias(struct inode *inode) |
1da177e4 | 659 | { |
214fda1f DH |
660 | struct dentry *de = NULL; |
661 | ||
662 | if (!list_empty(&inode->i_dentry)) { | |
873feea0 | 663 | spin_lock(&inode->i_lock); |
214fda1f | 664 | de = __d_find_alias(inode, 0); |
873feea0 | 665 | spin_unlock(&inode->i_lock); |
214fda1f | 666 | } |
1da177e4 LT |
667 | return de; |
668 | } | |
ec4f8605 | 669 | EXPORT_SYMBOL(d_find_alias); |
1da177e4 LT |
670 | |
671 | /* | |
672 | * Try to kill dentries associated with this inode. | |
673 | * WARNING: you must own a reference to inode. | |
674 | */ | |
675 | void d_prune_aliases(struct inode *inode) | |
676 | { | |
0cdca3f9 | 677 | struct dentry *dentry; |
1da177e4 | 678 | restart: |
873feea0 | 679 | spin_lock(&inode->i_lock); |
0cdca3f9 | 680 | list_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
1da177e4 | 681 | spin_lock(&dentry->d_lock); |
b7ab39f6 | 682 | if (!dentry->d_count) { |
dc0474be | 683 | __dget_dlock(dentry); |
1da177e4 LT |
684 | __d_drop(dentry); |
685 | spin_unlock(&dentry->d_lock); | |
873feea0 | 686 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
687 | dput(dentry); |
688 | goto restart; | |
689 | } | |
690 | spin_unlock(&dentry->d_lock); | |
691 | } | |
873feea0 | 692 | spin_unlock(&inode->i_lock); |
1da177e4 | 693 | } |
ec4f8605 | 694 | EXPORT_SYMBOL(d_prune_aliases); |
1da177e4 LT |
695 | |
696 | /* | |
77812a1e NP |
697 | * Try to throw away a dentry - free the inode, dput the parent. |
698 | * Requires dentry->d_lock is held, and dentry->d_count == 0. | |
699 | * Releases dentry->d_lock. | |
d702ccb3 | 700 | * |
77812a1e | 701 | * This may fail if locks cannot be acquired no problem, just try again. |
1da177e4 | 702 | */ |
77812a1e | 703 | static void try_prune_one_dentry(struct dentry *dentry) |
31f3e0b3 | 704 | __releases(dentry->d_lock) |
1da177e4 | 705 | { |
77812a1e | 706 | struct dentry *parent; |
d52b9086 | 707 | |
77812a1e | 708 | parent = dentry_kill(dentry, 0); |
d52b9086 | 709 | /* |
77812a1e NP |
710 | * If dentry_kill returns NULL, we have nothing more to do. |
711 | * if it returns the same dentry, trylocks failed. In either | |
712 | * case, just loop again. | |
713 | * | |
714 | * Otherwise, we need to prune ancestors too. This is necessary | |
715 | * to prevent quadratic behavior of shrink_dcache_parent(), but | |
716 | * is also expected to be beneficial in reducing dentry cache | |
717 | * fragmentation. | |
d52b9086 | 718 | */ |
77812a1e NP |
719 | if (!parent) |
720 | return; | |
721 | if (parent == dentry) | |
722 | return; | |
723 | ||
724 | /* Prune ancestors. */ | |
725 | dentry = parent; | |
d52b9086 | 726 | while (dentry) { |
b7ab39f6 | 727 | spin_lock(&dentry->d_lock); |
89e60548 NP |
728 | if (dentry->d_count > 1) { |
729 | dentry->d_count--; | |
730 | spin_unlock(&dentry->d_lock); | |
731 | return; | |
732 | } | |
77812a1e | 733 | dentry = dentry_kill(dentry, 1); |
d52b9086 | 734 | } |
1da177e4 LT |
735 | } |
736 | ||
3049cfe2 | 737 | static void shrink_dentry_list(struct list_head *list) |
1da177e4 | 738 | { |
da3bbdd4 | 739 | struct dentry *dentry; |
da3bbdd4 | 740 | |
ec33679d NP |
741 | rcu_read_lock(); |
742 | for (;;) { | |
ec33679d NP |
743 | dentry = list_entry_rcu(list->prev, struct dentry, d_lru); |
744 | if (&dentry->d_lru == list) | |
745 | break; /* empty */ | |
746 | spin_lock(&dentry->d_lock); | |
747 | if (dentry != list_entry(list->prev, struct dentry, d_lru)) { | |
748 | spin_unlock(&dentry->d_lock); | |
23044507 NP |
749 | continue; |
750 | } | |
751 | ||
1da177e4 LT |
752 | /* |
753 | * We found an inuse dentry which was not removed from | |
da3bbdd4 KM |
754 | * the LRU because of laziness during lookup. Do not free |
755 | * it - just keep it off the LRU list. | |
1da177e4 | 756 | */ |
b7ab39f6 | 757 | if (dentry->d_count) { |
ec33679d | 758 | dentry_lru_del(dentry); |
da3bbdd4 | 759 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
760 | continue; |
761 | } | |
ec33679d | 762 | |
ec33679d | 763 | rcu_read_unlock(); |
77812a1e NP |
764 | |
765 | try_prune_one_dentry(dentry); | |
766 | ||
ec33679d | 767 | rcu_read_lock(); |
da3bbdd4 | 768 | } |
ec33679d | 769 | rcu_read_unlock(); |
3049cfe2 CH |
770 | } |
771 | ||
772 | /** | |
773 | * __shrink_dcache_sb - shrink the dentry LRU on a given superblock | |
774 | * @sb: superblock to shrink dentry LRU. | |
775 | * @count: number of entries to prune | |
776 | * @flags: flags to control the dentry processing | |
777 | * | |
778 | * If flags contains DCACHE_REFERENCED reference dentries will not be pruned. | |
779 | */ | |
b0d40c92 | 780 | static void __shrink_dcache_sb(struct super_block *sb, int count, int flags) |
3049cfe2 | 781 | { |
3049cfe2 CH |
782 | struct dentry *dentry; |
783 | LIST_HEAD(referenced); | |
784 | LIST_HEAD(tmp); | |
3049cfe2 | 785 | |
23044507 NP |
786 | relock: |
787 | spin_lock(&dcache_lru_lock); | |
3049cfe2 CH |
788 | while (!list_empty(&sb->s_dentry_lru)) { |
789 | dentry = list_entry(sb->s_dentry_lru.prev, | |
790 | struct dentry, d_lru); | |
791 | BUG_ON(dentry->d_sb != sb); | |
792 | ||
23044507 NP |
793 | if (!spin_trylock(&dentry->d_lock)) { |
794 | spin_unlock(&dcache_lru_lock); | |
795 | cpu_relax(); | |
796 | goto relock; | |
797 | } | |
798 | ||
3049cfe2 CH |
799 | /* |
800 | * If we are honouring the DCACHE_REFERENCED flag and the | |
801 | * dentry has this flag set, don't free it. Clear the flag | |
802 | * and put it back on the LRU. | |
803 | */ | |
23044507 NP |
804 | if (flags & DCACHE_REFERENCED && |
805 | dentry->d_flags & DCACHE_REFERENCED) { | |
806 | dentry->d_flags &= ~DCACHE_REFERENCED; | |
807 | list_move(&dentry->d_lru, &referenced); | |
3049cfe2 | 808 | spin_unlock(&dentry->d_lock); |
23044507 NP |
809 | } else { |
810 | list_move_tail(&dentry->d_lru, &tmp); | |
811 | spin_unlock(&dentry->d_lock); | |
b0d40c92 | 812 | if (!--count) |
23044507 | 813 | break; |
3049cfe2 | 814 | } |
ec33679d | 815 | cond_resched_lock(&dcache_lru_lock); |
3049cfe2 | 816 | } |
da3bbdd4 KM |
817 | if (!list_empty(&referenced)) |
818 | list_splice(&referenced, &sb->s_dentry_lru); | |
23044507 | 819 | spin_unlock(&dcache_lru_lock); |
ec33679d NP |
820 | |
821 | shrink_dentry_list(&tmp); | |
da3bbdd4 KM |
822 | } |
823 | ||
824 | /** | |
b0d40c92 | 825 | * prune_dcache_sb - shrink the dcache |
2af14162 | 826 | * @sb: superblock |
b0d40c92 | 827 | * @nr_to_scan: number of entries to try to free |
da3bbdd4 | 828 | * |
b0d40c92 DC |
829 | * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is |
830 | * done when we need more memory an called from the superblock shrinker | |
831 | * function. | |
da3bbdd4 | 832 | * |
b0d40c92 DC |
833 | * This function may fail to free any resources if all the dentries are in |
834 | * use. | |
da3bbdd4 | 835 | */ |
b0d40c92 | 836 | void prune_dcache_sb(struct super_block *sb, int nr_to_scan) |
da3bbdd4 | 837 | { |
b0d40c92 | 838 | __shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED); |
1da177e4 LT |
839 | } |
840 | ||
1da177e4 LT |
841 | /** |
842 | * shrink_dcache_sb - shrink dcache for a superblock | |
843 | * @sb: superblock | |
844 | * | |
3049cfe2 CH |
845 | * Shrink the dcache for the specified super block. This is used to free |
846 | * the dcache before unmounting a file system. | |
1da177e4 | 847 | */ |
3049cfe2 | 848 | void shrink_dcache_sb(struct super_block *sb) |
1da177e4 | 849 | { |
3049cfe2 CH |
850 | LIST_HEAD(tmp); |
851 | ||
23044507 | 852 | spin_lock(&dcache_lru_lock); |
3049cfe2 CH |
853 | while (!list_empty(&sb->s_dentry_lru)) { |
854 | list_splice_init(&sb->s_dentry_lru, &tmp); | |
ec33679d | 855 | spin_unlock(&dcache_lru_lock); |
3049cfe2 | 856 | shrink_dentry_list(&tmp); |
ec33679d | 857 | spin_lock(&dcache_lru_lock); |
3049cfe2 | 858 | } |
23044507 | 859 | spin_unlock(&dcache_lru_lock); |
1da177e4 | 860 | } |
ec4f8605 | 861 | EXPORT_SYMBOL(shrink_dcache_sb); |
1da177e4 | 862 | |
c636ebdb DH |
863 | /* |
864 | * destroy a single subtree of dentries for unmount | |
865 | * - see the comments on shrink_dcache_for_umount() for a description of the | |
866 | * locking | |
867 | */ | |
868 | static void shrink_dcache_for_umount_subtree(struct dentry *dentry) | |
869 | { | |
870 | struct dentry *parent; | |
871 | ||
872 | BUG_ON(!IS_ROOT(dentry)); | |
873 | ||
c636ebdb DH |
874 | for (;;) { |
875 | /* descend to the first leaf in the current subtree */ | |
43c1c9cd | 876 | while (!list_empty(&dentry->d_subdirs)) |
c636ebdb DH |
877 | dentry = list_entry(dentry->d_subdirs.next, |
878 | struct dentry, d_u.d_child); | |
c636ebdb DH |
879 | |
880 | /* consume the dentries from this leaf up through its parents | |
881 | * until we find one with children or run out altogether */ | |
882 | do { | |
883 | struct inode *inode; | |
884 | ||
f0023bc6 SW |
885 | /* |
886 | * remove the dentry from the lru, and inform | |
887 | * the fs that this dentry is about to be | |
888 | * unhashed and destroyed. | |
889 | */ | |
890 | dentry_lru_prune(dentry); | |
43c1c9cd DH |
891 | __d_shrink(dentry); |
892 | ||
b7ab39f6 | 893 | if (dentry->d_count != 0) { |
c636ebdb DH |
894 | printk(KERN_ERR |
895 | "BUG: Dentry %p{i=%lx,n=%s}" | |
896 | " still in use (%d)" | |
897 | " [unmount of %s %s]\n", | |
898 | dentry, | |
899 | dentry->d_inode ? | |
900 | dentry->d_inode->i_ino : 0UL, | |
901 | dentry->d_name.name, | |
b7ab39f6 | 902 | dentry->d_count, |
c636ebdb DH |
903 | dentry->d_sb->s_type->name, |
904 | dentry->d_sb->s_id); | |
905 | BUG(); | |
906 | } | |
907 | ||
2fd6b7f5 | 908 | if (IS_ROOT(dentry)) { |
c636ebdb | 909 | parent = NULL; |
2fd6b7f5 NP |
910 | list_del(&dentry->d_u.d_child); |
911 | } else { | |
871c0067 | 912 | parent = dentry->d_parent; |
b7ab39f6 | 913 | parent->d_count--; |
2fd6b7f5 | 914 | list_del(&dentry->d_u.d_child); |
871c0067 | 915 | } |
c636ebdb | 916 | |
c636ebdb DH |
917 | inode = dentry->d_inode; |
918 | if (inode) { | |
919 | dentry->d_inode = NULL; | |
920 | list_del_init(&dentry->d_alias); | |
921 | if (dentry->d_op && dentry->d_op->d_iput) | |
922 | dentry->d_op->d_iput(dentry, inode); | |
923 | else | |
924 | iput(inode); | |
925 | } | |
926 | ||
927 | d_free(dentry); | |
928 | ||
929 | /* finished when we fall off the top of the tree, | |
930 | * otherwise we ascend to the parent and move to the | |
931 | * next sibling if there is one */ | |
932 | if (!parent) | |
312d3ca8 | 933 | return; |
c636ebdb | 934 | dentry = parent; |
c636ebdb DH |
935 | } while (list_empty(&dentry->d_subdirs)); |
936 | ||
937 | dentry = list_entry(dentry->d_subdirs.next, | |
938 | struct dentry, d_u.d_child); | |
939 | } | |
940 | } | |
941 | ||
942 | /* | |
943 | * destroy the dentries attached to a superblock on unmounting | |
b5c84bf6 | 944 | * - we don't need to use dentry->d_lock because: |
c636ebdb DH |
945 | * - the superblock is detached from all mountings and open files, so the |
946 | * dentry trees will not be rearranged by the VFS | |
947 | * - s_umount is write-locked, so the memory pressure shrinker will ignore | |
948 | * any dentries belonging to this superblock that it comes across | |
949 | * - the filesystem itself is no longer permitted to rearrange the dentries | |
950 | * in this superblock | |
951 | */ | |
952 | void shrink_dcache_for_umount(struct super_block *sb) | |
953 | { | |
954 | struct dentry *dentry; | |
955 | ||
956 | if (down_read_trylock(&sb->s_umount)) | |
957 | BUG(); | |
958 | ||
959 | dentry = sb->s_root; | |
960 | sb->s_root = NULL; | |
b7ab39f6 | 961 | dentry->d_count--; |
c636ebdb DH |
962 | shrink_dcache_for_umount_subtree(dentry); |
963 | ||
ceb5bdc2 NP |
964 | while (!hlist_bl_empty(&sb->s_anon)) { |
965 | dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash); | |
c636ebdb DH |
966 | shrink_dcache_for_umount_subtree(dentry); |
967 | } | |
968 | } | |
969 | ||
c826cb7d LT |
970 | /* |
971 | * This tries to ascend one level of parenthood, but | |
972 | * we can race with renaming, so we need to re-check | |
973 | * the parenthood after dropping the lock and check | |
974 | * that the sequence number still matches. | |
975 | */ | |
976 | static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq) | |
977 | { | |
978 | struct dentry *new = old->d_parent; | |
979 | ||
980 | rcu_read_lock(); | |
981 | spin_unlock(&old->d_lock); | |
982 | spin_lock(&new->d_lock); | |
983 | ||
984 | /* | |
985 | * might go back up the wrong parent if we have had a rename | |
986 | * or deletion | |
987 | */ | |
988 | if (new != old->d_parent || | |
c83ce989 | 989 | (old->d_flags & DCACHE_DISCONNECTED) || |
c826cb7d LT |
990 | (!locked && read_seqretry(&rename_lock, seq))) { |
991 | spin_unlock(&new->d_lock); | |
992 | new = NULL; | |
993 | } | |
994 | rcu_read_unlock(); | |
995 | return new; | |
996 | } | |
997 | ||
998 | ||
1da177e4 LT |
999 | /* |
1000 | * Search for at least 1 mount point in the dentry's subdirs. | |
1001 | * We descend to the next level whenever the d_subdirs | |
1002 | * list is non-empty and continue searching. | |
1003 | */ | |
1004 | ||
1005 | /** | |
1006 | * have_submounts - check for mounts over a dentry | |
1007 | * @parent: dentry to check. | |
1008 | * | |
1009 | * Return true if the parent or its subdirectories contain | |
1010 | * a mount point | |
1011 | */ | |
1da177e4 LT |
1012 | int have_submounts(struct dentry *parent) |
1013 | { | |
949854d0 | 1014 | struct dentry *this_parent; |
1da177e4 | 1015 | struct list_head *next; |
949854d0 | 1016 | unsigned seq; |
58db63d0 | 1017 | int locked = 0; |
949854d0 | 1018 | |
949854d0 | 1019 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
1020 | again: |
1021 | this_parent = parent; | |
1da177e4 | 1022 | |
1da177e4 LT |
1023 | if (d_mountpoint(parent)) |
1024 | goto positive; | |
2fd6b7f5 | 1025 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
1026 | repeat: |
1027 | next = this_parent->d_subdirs.next; | |
1028 | resume: | |
1029 | while (next != &this_parent->d_subdirs) { | |
1030 | struct list_head *tmp = next; | |
5160ee6f | 1031 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 | 1032 | next = tmp->next; |
2fd6b7f5 NP |
1033 | |
1034 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); | |
1da177e4 | 1035 | /* Have we found a mount point ? */ |
2fd6b7f5 NP |
1036 | if (d_mountpoint(dentry)) { |
1037 | spin_unlock(&dentry->d_lock); | |
1038 | spin_unlock(&this_parent->d_lock); | |
1da177e4 | 1039 | goto positive; |
2fd6b7f5 | 1040 | } |
1da177e4 | 1041 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
1042 | spin_unlock(&this_parent->d_lock); |
1043 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 1044 | this_parent = dentry; |
2fd6b7f5 | 1045 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
1046 | goto repeat; |
1047 | } | |
2fd6b7f5 | 1048 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
1049 | } |
1050 | /* | |
1051 | * All done at this level ... ascend and resume the search. | |
1052 | */ | |
1053 | if (this_parent != parent) { | |
c826cb7d LT |
1054 | struct dentry *child = this_parent; |
1055 | this_parent = try_to_ascend(this_parent, locked, seq); | |
1056 | if (!this_parent) | |
949854d0 | 1057 | goto rename_retry; |
949854d0 | 1058 | next = child->d_u.d_child.next; |
1da177e4 LT |
1059 | goto resume; |
1060 | } | |
2fd6b7f5 | 1061 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 1062 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1063 | goto rename_retry; |
58db63d0 NP |
1064 | if (locked) |
1065 | write_sequnlock(&rename_lock); | |
1da177e4 LT |
1066 | return 0; /* No mount points found in tree */ |
1067 | positive: | |
58db63d0 | 1068 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1069 | goto rename_retry; |
58db63d0 NP |
1070 | if (locked) |
1071 | write_sequnlock(&rename_lock); | |
1da177e4 | 1072 | return 1; |
58db63d0 NP |
1073 | |
1074 | rename_retry: | |
1075 | locked = 1; | |
1076 | write_seqlock(&rename_lock); | |
1077 | goto again; | |
1da177e4 | 1078 | } |
ec4f8605 | 1079 | EXPORT_SYMBOL(have_submounts); |
1da177e4 LT |
1080 | |
1081 | /* | |
1082 | * Search the dentry child list for the specified parent, | |
1083 | * and move any unused dentries to the end of the unused | |
1084 | * list for prune_dcache(). We descend to the next level | |
1085 | * whenever the d_subdirs list is non-empty and continue | |
1086 | * searching. | |
1087 | * | |
1088 | * It returns zero iff there are no unused children, | |
1089 | * otherwise it returns the number of children moved to | |
1090 | * the end of the unused list. This may not be the total | |
1091 | * number of unused children, because select_parent can | |
1092 | * drop the lock and return early due to latency | |
1093 | * constraints. | |
1094 | */ | |
1095 | static int select_parent(struct dentry * parent) | |
1096 | { | |
949854d0 | 1097 | struct dentry *this_parent; |
1da177e4 | 1098 | struct list_head *next; |
949854d0 | 1099 | unsigned seq; |
1da177e4 | 1100 | int found = 0; |
58db63d0 | 1101 | int locked = 0; |
1da177e4 | 1102 | |
949854d0 | 1103 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
1104 | again: |
1105 | this_parent = parent; | |
2fd6b7f5 | 1106 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
1107 | repeat: |
1108 | next = this_parent->d_subdirs.next; | |
1109 | resume: | |
1110 | while (next != &this_parent->d_subdirs) { | |
1111 | struct list_head *tmp = next; | |
5160ee6f | 1112 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 LT |
1113 | next = tmp->next; |
1114 | ||
2fd6b7f5 | 1115 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
23044507 | 1116 | |
1da177e4 LT |
1117 | /* |
1118 | * move only zero ref count dentries to the end | |
1119 | * of the unused list for prune_dcache | |
1120 | */ | |
b7ab39f6 | 1121 | if (!dentry->d_count) { |
a4633357 | 1122 | dentry_lru_move_tail(dentry); |
1da177e4 | 1123 | found++; |
a4633357 CH |
1124 | } else { |
1125 | dentry_lru_del(dentry); | |
1da177e4 LT |
1126 | } |
1127 | ||
1128 | /* | |
1129 | * We can return to the caller if we have found some (this | |
1130 | * ensures forward progress). We'll be coming back to find | |
1131 | * the rest. | |
1132 | */ | |
2fd6b7f5 NP |
1133 | if (found && need_resched()) { |
1134 | spin_unlock(&dentry->d_lock); | |
1da177e4 | 1135 | goto out; |
2fd6b7f5 | 1136 | } |
1da177e4 LT |
1137 | |
1138 | /* | |
1139 | * Descend a level if the d_subdirs list is non-empty. | |
1140 | */ | |
1141 | if (!list_empty(&dentry->d_subdirs)) { | |
2fd6b7f5 NP |
1142 | spin_unlock(&this_parent->d_lock); |
1143 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 1144 | this_parent = dentry; |
2fd6b7f5 | 1145 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
1146 | goto repeat; |
1147 | } | |
2fd6b7f5 NP |
1148 | |
1149 | spin_unlock(&dentry->d_lock); | |
1da177e4 LT |
1150 | } |
1151 | /* | |
1152 | * All done at this level ... ascend and resume the search. | |
1153 | */ | |
1154 | if (this_parent != parent) { | |
c826cb7d LT |
1155 | struct dentry *child = this_parent; |
1156 | this_parent = try_to_ascend(this_parent, locked, seq); | |
1157 | if (!this_parent) | |
949854d0 | 1158 | goto rename_retry; |
949854d0 | 1159 | next = child->d_u.d_child.next; |
1da177e4 LT |
1160 | goto resume; |
1161 | } | |
1162 | out: | |
2fd6b7f5 | 1163 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 1164 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 1165 | goto rename_retry; |
58db63d0 NP |
1166 | if (locked) |
1167 | write_sequnlock(&rename_lock); | |
1da177e4 | 1168 | return found; |
58db63d0 NP |
1169 | |
1170 | rename_retry: | |
1171 | if (found) | |
1172 | return found; | |
1173 | locked = 1; | |
1174 | write_seqlock(&rename_lock); | |
1175 | goto again; | |
1da177e4 LT |
1176 | } |
1177 | ||
1178 | /** | |
1179 | * shrink_dcache_parent - prune dcache | |
1180 | * @parent: parent of entries to prune | |
1181 | * | |
1182 | * Prune the dcache to remove unused children of the parent dentry. | |
1183 | */ | |
1184 | ||
1185 | void shrink_dcache_parent(struct dentry * parent) | |
1186 | { | |
da3bbdd4 | 1187 | struct super_block *sb = parent->d_sb; |
1da177e4 LT |
1188 | int found; |
1189 | ||
1190 | while ((found = select_parent(parent)) != 0) | |
b0d40c92 | 1191 | __shrink_dcache_sb(sb, found, 0); |
1da177e4 | 1192 | } |
ec4f8605 | 1193 | EXPORT_SYMBOL(shrink_dcache_parent); |
1da177e4 | 1194 | |
1da177e4 | 1195 | /** |
a4464dbc AV |
1196 | * __d_alloc - allocate a dcache entry |
1197 | * @sb: filesystem it will belong to | |
1da177e4 LT |
1198 | * @name: qstr of the name |
1199 | * | |
1200 | * Allocates a dentry. It returns %NULL if there is insufficient memory | |
1201 | * available. On a success the dentry is returned. The name passed in is | |
1202 | * copied and the copy passed in may be reused after this call. | |
1203 | */ | |
1204 | ||
a4464dbc | 1205 | struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) |
1da177e4 LT |
1206 | { |
1207 | struct dentry *dentry; | |
1208 | char *dname; | |
1209 | ||
e12ba74d | 1210 | dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); |
1da177e4 LT |
1211 | if (!dentry) |
1212 | return NULL; | |
1213 | ||
1214 | if (name->len > DNAME_INLINE_LEN-1) { | |
1215 | dname = kmalloc(name->len + 1, GFP_KERNEL); | |
1216 | if (!dname) { | |
1217 | kmem_cache_free(dentry_cache, dentry); | |
1218 | return NULL; | |
1219 | } | |
1220 | } else { | |
1221 | dname = dentry->d_iname; | |
1222 | } | |
1223 | dentry->d_name.name = dname; | |
1224 | ||
1225 | dentry->d_name.len = name->len; | |
1226 | dentry->d_name.hash = name->hash; | |
1227 | memcpy(dname, name->name, name->len); | |
1228 | dname[name->len] = 0; | |
1229 | ||
b7ab39f6 | 1230 | dentry->d_count = 1; |
dea3667b | 1231 | dentry->d_flags = 0; |
1da177e4 | 1232 | spin_lock_init(&dentry->d_lock); |
31e6b01f | 1233 | seqcount_init(&dentry->d_seq); |
1da177e4 | 1234 | dentry->d_inode = NULL; |
a4464dbc AV |
1235 | dentry->d_parent = dentry; |
1236 | dentry->d_sb = sb; | |
1da177e4 LT |
1237 | dentry->d_op = NULL; |
1238 | dentry->d_fsdata = NULL; | |
ceb5bdc2 | 1239 | INIT_HLIST_BL_NODE(&dentry->d_hash); |
1da177e4 LT |
1240 | INIT_LIST_HEAD(&dentry->d_lru); |
1241 | INIT_LIST_HEAD(&dentry->d_subdirs); | |
1242 | INIT_LIST_HEAD(&dentry->d_alias); | |
2fd6b7f5 | 1243 | INIT_LIST_HEAD(&dentry->d_u.d_child); |
a4464dbc | 1244 | d_set_d_op(dentry, dentry->d_sb->s_d_op); |
1da177e4 | 1245 | |
3e880fb5 | 1246 | this_cpu_inc(nr_dentry); |
312d3ca8 | 1247 | |
1da177e4 LT |
1248 | return dentry; |
1249 | } | |
a4464dbc AV |
1250 | |
1251 | /** | |
1252 | * d_alloc - allocate a dcache entry | |
1253 | * @parent: parent of entry to allocate | |
1254 | * @name: qstr of the name | |
1255 | * | |
1256 | * Allocates a dentry. It returns %NULL if there is insufficient memory | |
1257 | * available. On a success the dentry is returned. The name passed in is | |
1258 | * copied and the copy passed in may be reused after this call. | |
1259 | */ | |
1260 | struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) | |
1261 | { | |
1262 | struct dentry *dentry = __d_alloc(parent->d_sb, name); | |
1263 | if (!dentry) | |
1264 | return NULL; | |
1265 | ||
1266 | spin_lock(&parent->d_lock); | |
1267 | /* | |
1268 | * don't need child lock because it is not subject | |
1269 | * to concurrency here | |
1270 | */ | |
1271 | __dget_dlock(parent); | |
1272 | dentry->d_parent = parent; | |
1273 | list_add(&dentry->d_u.d_child, &parent->d_subdirs); | |
1274 | spin_unlock(&parent->d_lock); | |
1275 | ||
1276 | return dentry; | |
1277 | } | |
ec4f8605 | 1278 | EXPORT_SYMBOL(d_alloc); |
1da177e4 | 1279 | |
4b936885 NP |
1280 | struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) |
1281 | { | |
a4464dbc AV |
1282 | struct dentry *dentry = __d_alloc(sb, name); |
1283 | if (dentry) | |
4b936885 | 1284 | dentry->d_flags |= DCACHE_DISCONNECTED; |
4b936885 NP |
1285 | return dentry; |
1286 | } | |
1287 | EXPORT_SYMBOL(d_alloc_pseudo); | |
1288 | ||
1da177e4 LT |
1289 | struct dentry *d_alloc_name(struct dentry *parent, const char *name) |
1290 | { | |
1291 | struct qstr q; | |
1292 | ||
1293 | q.name = name; | |
1294 | q.len = strlen(name); | |
1295 | q.hash = full_name_hash(q.name, q.len); | |
1296 | return d_alloc(parent, &q); | |
1297 | } | |
ef26ca97 | 1298 | EXPORT_SYMBOL(d_alloc_name); |
1da177e4 | 1299 | |
fb045adb NP |
1300 | void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) |
1301 | { | |
6f7f7caa LT |
1302 | WARN_ON_ONCE(dentry->d_op); |
1303 | WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | | |
fb045adb NP |
1304 | DCACHE_OP_COMPARE | |
1305 | DCACHE_OP_REVALIDATE | | |
1306 | DCACHE_OP_DELETE )); | |
1307 | dentry->d_op = op; | |
1308 | if (!op) | |
1309 | return; | |
1310 | if (op->d_hash) | |
1311 | dentry->d_flags |= DCACHE_OP_HASH; | |
1312 | if (op->d_compare) | |
1313 | dentry->d_flags |= DCACHE_OP_COMPARE; | |
1314 | if (op->d_revalidate) | |
1315 | dentry->d_flags |= DCACHE_OP_REVALIDATE; | |
1316 | if (op->d_delete) | |
1317 | dentry->d_flags |= DCACHE_OP_DELETE; | |
f0023bc6 SW |
1318 | if (op->d_prune) |
1319 | dentry->d_flags |= DCACHE_OP_PRUNE; | |
fb045adb NP |
1320 | |
1321 | } | |
1322 | EXPORT_SYMBOL(d_set_d_op); | |
1323 | ||
360da900 OH |
1324 | static void __d_instantiate(struct dentry *dentry, struct inode *inode) |
1325 | { | |
b23fb0a6 | 1326 | spin_lock(&dentry->d_lock); |
9875cf80 DH |
1327 | if (inode) { |
1328 | if (unlikely(IS_AUTOMOUNT(inode))) | |
1329 | dentry->d_flags |= DCACHE_NEED_AUTOMOUNT; | |
360da900 | 1330 | list_add(&dentry->d_alias, &inode->i_dentry); |
9875cf80 | 1331 | } |
360da900 | 1332 | dentry->d_inode = inode; |
31e6b01f | 1333 | dentry_rcuwalk_barrier(dentry); |
b23fb0a6 | 1334 | spin_unlock(&dentry->d_lock); |
360da900 OH |
1335 | fsnotify_d_instantiate(dentry, inode); |
1336 | } | |
1337 | ||
1da177e4 LT |
1338 | /** |
1339 | * d_instantiate - fill in inode information for a dentry | |
1340 | * @entry: dentry to complete | |
1341 | * @inode: inode to attach to this dentry | |
1342 | * | |
1343 | * Fill in inode information in the entry. | |
1344 | * | |
1345 | * This turns negative dentries into productive full members | |
1346 | * of society. | |
1347 | * | |
1348 | * NOTE! This assumes that the inode count has been incremented | |
1349 | * (or otherwise set) by the caller to indicate that it is now | |
1350 | * in use by the dcache. | |
1351 | */ | |
1352 | ||
1353 | void d_instantiate(struct dentry *entry, struct inode * inode) | |
1354 | { | |
28133c7b | 1355 | BUG_ON(!list_empty(&entry->d_alias)); |
873feea0 NP |
1356 | if (inode) |
1357 | spin_lock(&inode->i_lock); | |
360da900 | 1358 | __d_instantiate(entry, inode); |
873feea0 NP |
1359 | if (inode) |
1360 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
1361 | security_d_instantiate(entry, inode); |
1362 | } | |
ec4f8605 | 1363 | EXPORT_SYMBOL(d_instantiate); |
1da177e4 LT |
1364 | |
1365 | /** | |
1366 | * d_instantiate_unique - instantiate a non-aliased dentry | |
1367 | * @entry: dentry to instantiate | |
1368 | * @inode: inode to attach to this dentry | |
1369 | * | |
1370 | * Fill in inode information in the entry. On success, it returns NULL. | |
1371 | * If an unhashed alias of "entry" already exists, then we return the | |
e866cfa9 | 1372 | * aliased dentry instead and drop one reference to inode. |
1da177e4 LT |
1373 | * |
1374 | * Note that in order to avoid conflicts with rename() etc, the caller | |
1375 | * had better be holding the parent directory semaphore. | |
e866cfa9 OD |
1376 | * |
1377 | * This also assumes that the inode count has been incremented | |
1378 | * (or otherwise set) by the caller to indicate that it is now | |
1379 | * in use by the dcache. | |
1da177e4 | 1380 | */ |
770bfad8 DH |
1381 | static struct dentry *__d_instantiate_unique(struct dentry *entry, |
1382 | struct inode *inode) | |
1da177e4 LT |
1383 | { |
1384 | struct dentry *alias; | |
1385 | int len = entry->d_name.len; | |
1386 | const char *name = entry->d_name.name; | |
1387 | unsigned int hash = entry->d_name.hash; | |
1388 | ||
770bfad8 | 1389 | if (!inode) { |
360da900 | 1390 | __d_instantiate(entry, NULL); |
770bfad8 DH |
1391 | return NULL; |
1392 | } | |
1393 | ||
1da177e4 LT |
1394 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
1395 | struct qstr *qstr = &alias->d_name; | |
1396 | ||
9abca360 NP |
1397 | /* |
1398 | * Don't need alias->d_lock here, because aliases with | |
1399 | * d_parent == entry->d_parent are not subject to name or | |
1400 | * parent changes, because the parent inode i_mutex is held. | |
1401 | */ | |
1da177e4 LT |
1402 | if (qstr->hash != hash) |
1403 | continue; | |
1404 | if (alias->d_parent != entry->d_parent) | |
1405 | continue; | |
9d55c369 | 1406 | if (dentry_cmp(qstr->name, qstr->len, name, len)) |
1da177e4 | 1407 | continue; |
dc0474be | 1408 | __dget(alias); |
1da177e4 LT |
1409 | return alias; |
1410 | } | |
770bfad8 | 1411 | |
360da900 | 1412 | __d_instantiate(entry, inode); |
1da177e4 LT |
1413 | return NULL; |
1414 | } | |
770bfad8 DH |
1415 | |
1416 | struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) | |
1417 | { | |
1418 | struct dentry *result; | |
1419 | ||
1420 | BUG_ON(!list_empty(&entry->d_alias)); | |
1421 | ||
873feea0 NP |
1422 | if (inode) |
1423 | spin_lock(&inode->i_lock); | |
770bfad8 | 1424 | result = __d_instantiate_unique(entry, inode); |
873feea0 NP |
1425 | if (inode) |
1426 | spin_unlock(&inode->i_lock); | |
770bfad8 DH |
1427 | |
1428 | if (!result) { | |
1429 | security_d_instantiate(entry, inode); | |
1430 | return NULL; | |
1431 | } | |
1432 | ||
1433 | BUG_ON(!d_unhashed(result)); | |
1434 | iput(inode); | |
1435 | return result; | |
1436 | } | |
1437 | ||
1da177e4 LT |
1438 | EXPORT_SYMBOL(d_instantiate_unique); |
1439 | ||
1440 | /** | |
1441 | * d_alloc_root - allocate root dentry | |
1442 | * @root_inode: inode to allocate the root for | |
1443 | * | |
1444 | * Allocate a root ("/") dentry for the inode given. The inode is | |
1445 | * instantiated and returned. %NULL is returned if there is insufficient | |
1446 | * memory or the inode passed is %NULL. | |
1447 | */ | |
1448 | ||
1449 | struct dentry * d_alloc_root(struct inode * root_inode) | |
1450 | { | |
1451 | struct dentry *res = NULL; | |
1452 | ||
1453 | if (root_inode) { | |
1454 | static const struct qstr name = { .name = "/", .len = 1 }; | |
1455 | ||
a4464dbc AV |
1456 | res = __d_alloc(root_inode->i_sb, &name); |
1457 | if (res) | |
1da177e4 | 1458 | d_instantiate(res, root_inode); |
1da177e4 LT |
1459 | } |
1460 | return res; | |
1461 | } | |
ec4f8605 | 1462 | EXPORT_SYMBOL(d_alloc_root); |
1da177e4 | 1463 | |
d891eedb BF |
1464 | static struct dentry * __d_find_any_alias(struct inode *inode) |
1465 | { | |
1466 | struct dentry *alias; | |
1467 | ||
1468 | if (list_empty(&inode->i_dentry)) | |
1469 | return NULL; | |
1470 | alias = list_first_entry(&inode->i_dentry, struct dentry, d_alias); | |
1471 | __dget(alias); | |
1472 | return alias; | |
1473 | } | |
1474 | ||
1475 | static struct dentry * d_find_any_alias(struct inode *inode) | |
1476 | { | |
1477 | struct dentry *de; | |
1478 | ||
1479 | spin_lock(&inode->i_lock); | |
1480 | de = __d_find_any_alias(inode); | |
1481 | spin_unlock(&inode->i_lock); | |
1482 | return de; | |
1483 | } | |
1484 | ||
1485 | ||
4ea3ada2 CH |
1486 | /** |
1487 | * d_obtain_alias - find or allocate a dentry for a given inode | |
1488 | * @inode: inode to allocate the dentry for | |
1489 | * | |
1490 | * Obtain a dentry for an inode resulting from NFS filehandle conversion or | |
1491 | * similar open by handle operations. The returned dentry may be anonymous, | |
1492 | * or may have a full name (if the inode was already in the cache). | |
1493 | * | |
1494 | * When called on a directory inode, we must ensure that the inode only ever | |
1495 | * has one dentry. If a dentry is found, that is returned instead of | |
1496 | * allocating a new one. | |
1497 | * | |
1498 | * On successful return, the reference to the inode has been transferred | |
44003728 CH |
1499 | * to the dentry. In case of an error the reference on the inode is released. |
1500 | * To make it easier to use in export operations a %NULL or IS_ERR inode may | |
1501 | * be passed in and will be the error will be propagate to the return value, | |
1502 | * with a %NULL @inode replaced by ERR_PTR(-ESTALE). | |
4ea3ada2 CH |
1503 | */ |
1504 | struct dentry *d_obtain_alias(struct inode *inode) | |
1505 | { | |
9308a612 CH |
1506 | static const struct qstr anonstring = { .name = "" }; |
1507 | struct dentry *tmp; | |
1508 | struct dentry *res; | |
4ea3ada2 CH |
1509 | |
1510 | if (!inode) | |
44003728 | 1511 | return ERR_PTR(-ESTALE); |
4ea3ada2 CH |
1512 | if (IS_ERR(inode)) |
1513 | return ERR_CAST(inode); | |
1514 | ||
d891eedb | 1515 | res = d_find_any_alias(inode); |
9308a612 CH |
1516 | if (res) |
1517 | goto out_iput; | |
1518 | ||
a4464dbc | 1519 | tmp = __d_alloc(inode->i_sb, &anonstring); |
9308a612 CH |
1520 | if (!tmp) { |
1521 | res = ERR_PTR(-ENOMEM); | |
1522 | goto out_iput; | |
4ea3ada2 | 1523 | } |
b5c84bf6 | 1524 | |
873feea0 | 1525 | spin_lock(&inode->i_lock); |
d891eedb | 1526 | res = __d_find_any_alias(inode); |
9308a612 | 1527 | if (res) { |
873feea0 | 1528 | spin_unlock(&inode->i_lock); |
9308a612 CH |
1529 | dput(tmp); |
1530 | goto out_iput; | |
1531 | } | |
1532 | ||
1533 | /* attach a disconnected dentry */ | |
1534 | spin_lock(&tmp->d_lock); | |
9308a612 CH |
1535 | tmp->d_inode = inode; |
1536 | tmp->d_flags |= DCACHE_DISCONNECTED; | |
9308a612 | 1537 | list_add(&tmp->d_alias, &inode->i_dentry); |
1879fd6a | 1538 | hlist_bl_lock(&tmp->d_sb->s_anon); |
ceb5bdc2 | 1539 | hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); |
1879fd6a | 1540 | hlist_bl_unlock(&tmp->d_sb->s_anon); |
9308a612 | 1541 | spin_unlock(&tmp->d_lock); |
873feea0 | 1542 | spin_unlock(&inode->i_lock); |
24ff6663 | 1543 | security_d_instantiate(tmp, inode); |
9308a612 | 1544 | |
9308a612 CH |
1545 | return tmp; |
1546 | ||
1547 | out_iput: | |
24ff6663 JB |
1548 | if (res && !IS_ERR(res)) |
1549 | security_d_instantiate(res, inode); | |
9308a612 CH |
1550 | iput(inode); |
1551 | return res; | |
4ea3ada2 | 1552 | } |
adc48720 | 1553 | EXPORT_SYMBOL(d_obtain_alias); |
1da177e4 LT |
1554 | |
1555 | /** | |
1556 | * d_splice_alias - splice a disconnected dentry into the tree if one exists | |
1557 | * @inode: the inode which may have a disconnected dentry | |
1558 | * @dentry: a negative dentry which we want to point to the inode. | |
1559 | * | |
1560 | * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and | |
1561 | * DCACHE_DISCONNECTED), then d_move that in place of the given dentry | |
1562 | * and return it, else simply d_add the inode to the dentry and return NULL. | |
1563 | * | |
1564 | * This is needed in the lookup routine of any filesystem that is exportable | |
1565 | * (via knfsd) so that we can build dcache paths to directories effectively. | |
1566 | * | |
1567 | * If a dentry was found and moved, then it is returned. Otherwise NULL | |
1568 | * is returned. This matches the expected return value of ->lookup. | |
1569 | * | |
1570 | */ | |
1571 | struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) | |
1572 | { | |
1573 | struct dentry *new = NULL; | |
1574 | ||
a9049376 AV |
1575 | if (IS_ERR(inode)) |
1576 | return ERR_CAST(inode); | |
1577 | ||
21c0d8fd | 1578 | if (inode && S_ISDIR(inode->i_mode)) { |
873feea0 | 1579 | spin_lock(&inode->i_lock); |
1da177e4 LT |
1580 | new = __d_find_alias(inode, 1); |
1581 | if (new) { | |
1582 | BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); | |
873feea0 | 1583 | spin_unlock(&inode->i_lock); |
1da177e4 | 1584 | security_d_instantiate(new, inode); |
1da177e4 LT |
1585 | d_move(new, dentry); |
1586 | iput(inode); | |
1587 | } else { | |
873feea0 | 1588 | /* already taking inode->i_lock, so d_add() by hand */ |
360da900 | 1589 | __d_instantiate(dentry, inode); |
873feea0 | 1590 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
1591 | security_d_instantiate(dentry, inode); |
1592 | d_rehash(dentry); | |
1593 | } | |
1594 | } else | |
1595 | d_add(dentry, inode); | |
1596 | return new; | |
1597 | } | |
ec4f8605 | 1598 | EXPORT_SYMBOL(d_splice_alias); |
1da177e4 | 1599 | |
9403540c BN |
1600 | /** |
1601 | * d_add_ci - lookup or allocate new dentry with case-exact name | |
1602 | * @inode: the inode case-insensitive lookup has found | |
1603 | * @dentry: the negative dentry that was passed to the parent's lookup func | |
1604 | * @name: the case-exact name to be associated with the returned dentry | |
1605 | * | |
1606 | * This is to avoid filling the dcache with case-insensitive names to the | |
1607 | * same inode, only the actual correct case is stored in the dcache for | |
1608 | * case-insensitive filesystems. | |
1609 | * | |
1610 | * For a case-insensitive lookup match and if the the case-exact dentry | |
1611 | * already exists in in the dcache, use it and return it. | |
1612 | * | |
1613 | * If no entry exists with the exact case name, allocate new dentry with | |
1614 | * the exact case, and return the spliced entry. | |
1615 | */ | |
e45b590b | 1616 | struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, |
9403540c BN |
1617 | struct qstr *name) |
1618 | { | |
1619 | int error; | |
1620 | struct dentry *found; | |
1621 | struct dentry *new; | |
1622 | ||
b6520c81 CH |
1623 | /* |
1624 | * First check if a dentry matching the name already exists, | |
1625 | * if not go ahead and create it now. | |
1626 | */ | |
9403540c | 1627 | found = d_hash_and_lookup(dentry->d_parent, name); |
9403540c BN |
1628 | if (!found) { |
1629 | new = d_alloc(dentry->d_parent, name); | |
1630 | if (!new) { | |
1631 | error = -ENOMEM; | |
1632 | goto err_out; | |
1633 | } | |
b6520c81 | 1634 | |
9403540c BN |
1635 | found = d_splice_alias(inode, new); |
1636 | if (found) { | |
1637 | dput(new); | |
1638 | return found; | |
1639 | } | |
1640 | return new; | |
1641 | } | |
b6520c81 CH |
1642 | |
1643 | /* | |
1644 | * If a matching dentry exists, and it's not negative use it. | |
1645 | * | |
1646 | * Decrement the reference count to balance the iget() done | |
1647 | * earlier on. | |
1648 | */ | |
9403540c BN |
1649 | if (found->d_inode) { |
1650 | if (unlikely(found->d_inode != inode)) { | |
1651 | /* This can't happen because bad inodes are unhashed. */ | |
1652 | BUG_ON(!is_bad_inode(inode)); | |
1653 | BUG_ON(!is_bad_inode(found->d_inode)); | |
1654 | } | |
9403540c BN |
1655 | iput(inode); |
1656 | return found; | |
1657 | } | |
b6520c81 | 1658 | |
9403540c | 1659 | /* |
44396f4b JB |
1660 | * We are going to instantiate this dentry, unhash it and clear the |
1661 | * lookup flag so we can do that. | |
9403540c | 1662 | */ |
44396f4b JB |
1663 | if (unlikely(d_need_lookup(found))) |
1664 | d_clear_need_lookup(found); | |
b6520c81 | 1665 | |
9403540c | 1666 | /* |
9403540c | 1667 | * Negative dentry: instantiate it unless the inode is a directory and |
b6520c81 | 1668 | * already has a dentry. |
9403540c | 1669 | */ |
4513d899 AV |
1670 | new = d_splice_alias(inode, found); |
1671 | if (new) { | |
1672 | dput(found); | |
1673 | found = new; | |
9403540c | 1674 | } |
4513d899 | 1675 | return found; |
9403540c BN |
1676 | |
1677 | err_out: | |
1678 | iput(inode); | |
1679 | return ERR_PTR(error); | |
1680 | } | |
ec4f8605 | 1681 | EXPORT_SYMBOL(d_add_ci); |
1da177e4 | 1682 | |
31e6b01f NP |
1683 | /** |
1684 | * __d_lookup_rcu - search for a dentry (racy, store-free) | |
1685 | * @parent: parent dentry | |
1686 | * @name: qstr of name we wish to find | |
1687 | * @seq: returns d_seq value at the point where the dentry was found | |
1688 | * @inode: returns dentry->d_inode when the inode was found valid. | |
1689 | * Returns: dentry, or NULL | |
1690 | * | |
1691 | * __d_lookup_rcu is the dcache lookup function for rcu-walk name | |
1692 | * resolution (store-free path walking) design described in | |
1693 | * Documentation/filesystems/path-lookup.txt. | |
1694 | * | |
1695 | * This is not to be used outside core vfs. | |
1696 | * | |
1697 | * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock | |
1698 | * held, and rcu_read_lock held. The returned dentry must not be stored into | |
1699 | * without taking d_lock and checking d_seq sequence count against @seq | |
1700 | * returned here. | |
1701 | * | |
1702 | * A refcount may be taken on the found dentry with the __d_rcu_to_refcount | |
1703 | * function. | |
1704 | * | |
1705 | * Alternatively, __d_lookup_rcu may be called again to look up the child of | |
1706 | * the returned dentry, so long as its parent's seqlock is checked after the | |
1707 | * child is looked up. Thus, an interlocking stepping of sequence lock checks | |
1708 | * is formed, giving integrity down the path walk. | |
1709 | */ | |
1710 | struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, | |
1711 | unsigned *seq, struct inode **inode) | |
1712 | { | |
1713 | unsigned int len = name->len; | |
1714 | unsigned int hash = name->hash; | |
1715 | const unsigned char *str = name->name; | |
b07ad996 | 1716 | struct hlist_bl_head *b = d_hash(parent, hash); |
ceb5bdc2 | 1717 | struct hlist_bl_node *node; |
31e6b01f NP |
1718 | struct dentry *dentry; |
1719 | ||
1720 | /* | |
1721 | * Note: There is significant duplication with __d_lookup_rcu which is | |
1722 | * required to prevent single threaded performance regressions | |
1723 | * especially on architectures where smp_rmb (in seqcounts) are costly. | |
1724 | * Keep the two functions in sync. | |
1725 | */ | |
1726 | ||
1727 | /* | |
1728 | * The hash list is protected using RCU. | |
1729 | * | |
1730 | * Carefully use d_seq when comparing a candidate dentry, to avoid | |
1731 | * races with d_move(). | |
1732 | * | |
1733 | * It is possible that concurrent renames can mess up our list | |
1734 | * walk here and result in missing our dentry, resulting in the | |
1735 | * false-negative result. d_lookup() protects against concurrent | |
1736 | * renames using rename_lock seqlock. | |
1737 | * | |
b0a4bb83 | 1738 | * See Documentation/filesystems/path-lookup.txt for more details. |
31e6b01f | 1739 | */ |
b07ad996 | 1740 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
31e6b01f NP |
1741 | struct inode *i; |
1742 | const char *tname; | |
1743 | int tlen; | |
1744 | ||
1745 | if (dentry->d_name.hash != hash) | |
1746 | continue; | |
1747 | ||
1748 | seqretry: | |
1749 | *seq = read_seqcount_begin(&dentry->d_seq); | |
1750 | if (dentry->d_parent != parent) | |
1751 | continue; | |
1752 | if (d_unhashed(dentry)) | |
1753 | continue; | |
1754 | tlen = dentry->d_name.len; | |
1755 | tname = dentry->d_name.name; | |
1756 | i = dentry->d_inode; | |
e1bb5782 | 1757 | prefetch(tname); |
31e6b01f NP |
1758 | /* |
1759 | * This seqcount check is required to ensure name and | |
1760 | * len are loaded atomically, so as not to walk off the | |
1761 | * edge of memory when walking. If we could load this | |
1762 | * atomically some other way, we could drop this check. | |
1763 | */ | |
1764 | if (read_seqcount_retry(&dentry->d_seq, *seq)) | |
1765 | goto seqretry; | |
830c0f0e | 1766 | if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { |
31e6b01f NP |
1767 | if (parent->d_op->d_compare(parent, *inode, |
1768 | dentry, i, | |
1769 | tlen, tname, name)) | |
1770 | continue; | |
1771 | } else { | |
9d55c369 | 1772 | if (dentry_cmp(tname, tlen, str, len)) |
31e6b01f NP |
1773 | continue; |
1774 | } | |
1775 | /* | |
1776 | * No extra seqcount check is required after the name | |
1777 | * compare. The caller must perform a seqcount check in | |
1778 | * order to do anything useful with the returned dentry | |
1779 | * anyway. | |
1780 | */ | |
1781 | *inode = i; | |
1782 | return dentry; | |
1783 | } | |
1784 | return NULL; | |
1785 | } | |
1786 | ||
1da177e4 LT |
1787 | /** |
1788 | * d_lookup - search for a dentry | |
1789 | * @parent: parent dentry | |
1790 | * @name: qstr of name we wish to find | |
b04f784e | 1791 | * Returns: dentry, or NULL |
1da177e4 | 1792 | * |
b04f784e NP |
1793 | * d_lookup searches the children of the parent dentry for the name in |
1794 | * question. If the dentry is found its reference count is incremented and the | |
1795 | * dentry is returned. The caller must use dput to free the entry when it has | |
1796 | * finished using it. %NULL is returned if the dentry does not exist. | |
1da177e4 | 1797 | */ |
31e6b01f | 1798 | struct dentry *d_lookup(struct dentry *parent, struct qstr *name) |
1da177e4 | 1799 | { |
31e6b01f | 1800 | struct dentry *dentry; |
949854d0 | 1801 | unsigned seq; |
1da177e4 LT |
1802 | |
1803 | do { | |
1804 | seq = read_seqbegin(&rename_lock); | |
1805 | dentry = __d_lookup(parent, name); | |
1806 | if (dentry) | |
1807 | break; | |
1808 | } while (read_seqretry(&rename_lock, seq)); | |
1809 | return dentry; | |
1810 | } | |
ec4f8605 | 1811 | EXPORT_SYMBOL(d_lookup); |
1da177e4 | 1812 | |
31e6b01f | 1813 | /** |
b04f784e NP |
1814 | * __d_lookup - search for a dentry (racy) |
1815 | * @parent: parent dentry | |
1816 | * @name: qstr of name we wish to find | |
1817 | * Returns: dentry, or NULL | |
1818 | * | |
1819 | * __d_lookup is like d_lookup, however it may (rarely) return a | |
1820 | * false-negative result due to unrelated rename activity. | |
1821 | * | |
1822 | * __d_lookup is slightly faster by avoiding rename_lock read seqlock, | |
1823 | * however it must be used carefully, eg. with a following d_lookup in | |
1824 | * the case of failure. | |
1825 | * | |
1826 | * __d_lookup callers must be commented. | |
1827 | */ | |
31e6b01f | 1828 | struct dentry *__d_lookup(struct dentry *parent, struct qstr *name) |
1da177e4 LT |
1829 | { |
1830 | unsigned int len = name->len; | |
1831 | unsigned int hash = name->hash; | |
1832 | const unsigned char *str = name->name; | |
b07ad996 | 1833 | struct hlist_bl_head *b = d_hash(parent, hash); |
ceb5bdc2 | 1834 | struct hlist_bl_node *node; |
31e6b01f | 1835 | struct dentry *found = NULL; |
665a7583 | 1836 | struct dentry *dentry; |
1da177e4 | 1837 | |
31e6b01f NP |
1838 | /* |
1839 | * Note: There is significant duplication with __d_lookup_rcu which is | |
1840 | * required to prevent single threaded performance regressions | |
1841 | * especially on architectures where smp_rmb (in seqcounts) are costly. | |
1842 | * Keep the two functions in sync. | |
1843 | */ | |
1844 | ||
b04f784e NP |
1845 | /* |
1846 | * The hash list is protected using RCU. | |
1847 | * | |
1848 | * Take d_lock when comparing a candidate dentry, to avoid races | |
1849 | * with d_move(). | |
1850 | * | |
1851 | * It is possible that concurrent renames can mess up our list | |
1852 | * walk here and result in missing our dentry, resulting in the | |
1853 | * false-negative result. d_lookup() protects against concurrent | |
1854 | * renames using rename_lock seqlock. | |
1855 | * | |
b0a4bb83 | 1856 | * See Documentation/filesystems/path-lookup.txt for more details. |
b04f784e | 1857 | */ |
1da177e4 LT |
1858 | rcu_read_lock(); |
1859 | ||
b07ad996 | 1860 | hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { |
31e6b01f NP |
1861 | const char *tname; |
1862 | int tlen; | |
1da177e4 | 1863 | |
1da177e4 LT |
1864 | if (dentry->d_name.hash != hash) |
1865 | continue; | |
1da177e4 LT |
1866 | |
1867 | spin_lock(&dentry->d_lock); | |
1da177e4 LT |
1868 | if (dentry->d_parent != parent) |
1869 | goto next; | |
d0185c08 LT |
1870 | if (d_unhashed(dentry)) |
1871 | goto next; | |
1872 | ||
1da177e4 LT |
1873 | /* |
1874 | * It is safe to compare names since d_move() cannot | |
1875 | * change the qstr (protected by d_lock). | |
1876 | */ | |
31e6b01f NP |
1877 | tlen = dentry->d_name.len; |
1878 | tname = dentry->d_name.name; | |
fb045adb | 1879 | if (parent->d_flags & DCACHE_OP_COMPARE) { |
621e155a NP |
1880 | if (parent->d_op->d_compare(parent, parent->d_inode, |
1881 | dentry, dentry->d_inode, | |
31e6b01f | 1882 | tlen, tname, name)) |
1da177e4 LT |
1883 | goto next; |
1884 | } else { | |
9d55c369 | 1885 | if (dentry_cmp(tname, tlen, str, len)) |
1da177e4 LT |
1886 | goto next; |
1887 | } | |
1888 | ||
b7ab39f6 | 1889 | dentry->d_count++; |
d0185c08 | 1890 | found = dentry; |
1da177e4 LT |
1891 | spin_unlock(&dentry->d_lock); |
1892 | break; | |
1893 | next: | |
1894 | spin_unlock(&dentry->d_lock); | |
1895 | } | |
1896 | rcu_read_unlock(); | |
1897 | ||
1898 | return found; | |
1899 | } | |
1900 | ||
3e7e241f EB |
1901 | /** |
1902 | * d_hash_and_lookup - hash the qstr then search for a dentry | |
1903 | * @dir: Directory to search in | |
1904 | * @name: qstr of name we wish to find | |
1905 | * | |
1906 | * On hash failure or on lookup failure NULL is returned. | |
1907 | */ | |
1908 | struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) | |
1909 | { | |
1910 | struct dentry *dentry = NULL; | |
1911 | ||
1912 | /* | |
1913 | * Check for a fs-specific hash function. Note that we must | |
1914 | * calculate the standard hash first, as the d_op->d_hash() | |
1915 | * routine may choose to leave the hash value unchanged. | |
1916 | */ | |
1917 | name->hash = full_name_hash(name->name, name->len); | |
fb045adb | 1918 | if (dir->d_flags & DCACHE_OP_HASH) { |
b1e6a015 | 1919 | if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0) |
3e7e241f EB |
1920 | goto out; |
1921 | } | |
1922 | dentry = d_lookup(dir, name); | |
1923 | out: | |
1924 | return dentry; | |
1925 | } | |
1926 | ||
1da177e4 | 1927 | /** |
786a5e15 | 1928 | * d_validate - verify dentry provided from insecure source (deprecated) |
1da177e4 | 1929 | * @dentry: The dentry alleged to be valid child of @dparent |
ff5fdb61 | 1930 | * @dparent: The parent dentry (known to be valid) |
1da177e4 LT |
1931 | * |
1932 | * An insecure source has sent us a dentry, here we verify it and dget() it. | |
1933 | * This is used by ncpfs in its readdir implementation. | |
1934 | * Zero is returned in the dentry is invalid. | |
786a5e15 NP |
1935 | * |
1936 | * This function is slow for big directories, and deprecated, do not use it. | |
1da177e4 | 1937 | */ |
d3a23e16 | 1938 | int d_validate(struct dentry *dentry, struct dentry *dparent) |
1da177e4 | 1939 | { |
786a5e15 | 1940 | struct dentry *child; |
d3a23e16 | 1941 | |
2fd6b7f5 | 1942 | spin_lock(&dparent->d_lock); |
786a5e15 NP |
1943 | list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { |
1944 | if (dentry == child) { | |
2fd6b7f5 | 1945 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
dc0474be | 1946 | __dget_dlock(dentry); |
2fd6b7f5 NP |
1947 | spin_unlock(&dentry->d_lock); |
1948 | spin_unlock(&dparent->d_lock); | |
1da177e4 LT |
1949 | return 1; |
1950 | } | |
1951 | } | |
2fd6b7f5 | 1952 | spin_unlock(&dparent->d_lock); |
786a5e15 | 1953 | |
1da177e4 LT |
1954 | return 0; |
1955 | } | |
ec4f8605 | 1956 | EXPORT_SYMBOL(d_validate); |
1da177e4 LT |
1957 | |
1958 | /* | |
1959 | * When a file is deleted, we have two options: | |
1960 | * - turn this dentry into a negative dentry | |
1961 | * - unhash this dentry and free it. | |
1962 | * | |
1963 | * Usually, we want to just turn this into | |
1964 | * a negative dentry, but if anybody else is | |
1965 | * currently using the dentry or the inode | |
1966 | * we can't do that and we fall back on removing | |
1967 | * it from the hash queues and waiting for | |
1968 | * it to be deleted later when it has no users | |
1969 | */ | |
1970 | ||
1971 | /** | |
1972 | * d_delete - delete a dentry | |
1973 | * @dentry: The dentry to delete | |
1974 | * | |
1975 | * Turn the dentry into a negative dentry if possible, otherwise | |
1976 | * remove it from the hash queues so it can be deleted later | |
1977 | */ | |
1978 | ||
1979 | void d_delete(struct dentry * dentry) | |
1980 | { | |
873feea0 | 1981 | struct inode *inode; |
7a91bf7f | 1982 | int isdir = 0; |
1da177e4 LT |
1983 | /* |
1984 | * Are we the only user? | |
1985 | */ | |
357f8e65 | 1986 | again: |
1da177e4 | 1987 | spin_lock(&dentry->d_lock); |
873feea0 NP |
1988 | inode = dentry->d_inode; |
1989 | isdir = S_ISDIR(inode->i_mode); | |
b7ab39f6 | 1990 | if (dentry->d_count == 1) { |
873feea0 | 1991 | if (inode && !spin_trylock(&inode->i_lock)) { |
357f8e65 NP |
1992 | spin_unlock(&dentry->d_lock); |
1993 | cpu_relax(); | |
1994 | goto again; | |
1995 | } | |
13e3c5e5 | 1996 | dentry->d_flags &= ~DCACHE_CANT_MOUNT; |
31e6b01f | 1997 | dentry_unlink_inode(dentry); |
7a91bf7f | 1998 | fsnotify_nameremove(dentry, isdir); |
1da177e4 LT |
1999 | return; |
2000 | } | |
2001 | ||
2002 | if (!d_unhashed(dentry)) | |
2003 | __d_drop(dentry); | |
2004 | ||
2005 | spin_unlock(&dentry->d_lock); | |
7a91bf7f JM |
2006 | |
2007 | fsnotify_nameremove(dentry, isdir); | |
1da177e4 | 2008 | } |
ec4f8605 | 2009 | EXPORT_SYMBOL(d_delete); |
1da177e4 | 2010 | |
b07ad996 | 2011 | static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) |
1da177e4 | 2012 | { |
ceb5bdc2 | 2013 | BUG_ON(!d_unhashed(entry)); |
1879fd6a | 2014 | hlist_bl_lock(b); |
dea3667b | 2015 | entry->d_flags |= DCACHE_RCUACCESS; |
b07ad996 | 2016 | hlist_bl_add_head_rcu(&entry->d_hash, b); |
1879fd6a | 2017 | hlist_bl_unlock(b); |
1da177e4 LT |
2018 | } |
2019 | ||
770bfad8 DH |
2020 | static void _d_rehash(struct dentry * entry) |
2021 | { | |
2022 | __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash)); | |
2023 | } | |
2024 | ||
1da177e4 LT |
2025 | /** |
2026 | * d_rehash - add an entry back to the hash | |
2027 | * @entry: dentry to add to the hash | |
2028 | * | |
2029 | * Adds a dentry to the hash according to its name. | |
2030 | */ | |
2031 | ||
2032 | void d_rehash(struct dentry * entry) | |
2033 | { | |
1da177e4 | 2034 | spin_lock(&entry->d_lock); |
770bfad8 | 2035 | _d_rehash(entry); |
1da177e4 | 2036 | spin_unlock(&entry->d_lock); |
1da177e4 | 2037 | } |
ec4f8605 | 2038 | EXPORT_SYMBOL(d_rehash); |
1da177e4 | 2039 | |
fb2d5b86 NP |
2040 | /** |
2041 | * dentry_update_name_case - update case insensitive dentry with a new name | |
2042 | * @dentry: dentry to be updated | |
2043 | * @name: new name | |
2044 | * | |
2045 | * Update a case insensitive dentry with new case of name. | |
2046 | * | |
2047 | * dentry must have been returned by d_lookup with name @name. Old and new | |
2048 | * name lengths must match (ie. no d_compare which allows mismatched name | |
2049 | * lengths). | |
2050 | * | |
2051 | * Parent inode i_mutex must be held over d_lookup and into this call (to | |
2052 | * keep renames and concurrent inserts, and readdir(2) away). | |
2053 | */ | |
2054 | void dentry_update_name_case(struct dentry *dentry, struct qstr *name) | |
2055 | { | |
7ebfa57f | 2056 | BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex)); |
fb2d5b86 NP |
2057 | BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ |
2058 | ||
fb2d5b86 | 2059 | spin_lock(&dentry->d_lock); |
31e6b01f | 2060 | write_seqcount_begin(&dentry->d_seq); |
fb2d5b86 | 2061 | memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); |
31e6b01f | 2062 | write_seqcount_end(&dentry->d_seq); |
fb2d5b86 | 2063 | spin_unlock(&dentry->d_lock); |
fb2d5b86 NP |
2064 | } |
2065 | EXPORT_SYMBOL(dentry_update_name_case); | |
2066 | ||
1da177e4 LT |
2067 | static void switch_names(struct dentry *dentry, struct dentry *target) |
2068 | { | |
2069 | if (dname_external(target)) { | |
2070 | if (dname_external(dentry)) { | |
2071 | /* | |
2072 | * Both external: swap the pointers | |
2073 | */ | |
9a8d5bb4 | 2074 | swap(target->d_name.name, dentry->d_name.name); |
1da177e4 LT |
2075 | } else { |
2076 | /* | |
2077 | * dentry:internal, target:external. Steal target's | |
2078 | * storage and make target internal. | |
2079 | */ | |
321bcf92 BF |
2080 | memcpy(target->d_iname, dentry->d_name.name, |
2081 | dentry->d_name.len + 1); | |
1da177e4 LT |
2082 | dentry->d_name.name = target->d_name.name; |
2083 | target->d_name.name = target->d_iname; | |
2084 | } | |
2085 | } else { | |
2086 | if (dname_external(dentry)) { | |
2087 | /* | |
2088 | * dentry:external, target:internal. Give dentry's | |
2089 | * storage to target and make dentry internal | |
2090 | */ | |
2091 | memcpy(dentry->d_iname, target->d_name.name, | |
2092 | target->d_name.len + 1); | |
2093 | target->d_name.name = dentry->d_name.name; | |
2094 | dentry->d_name.name = dentry->d_iname; | |
2095 | } else { | |
2096 | /* | |
2097 | * Both are internal. Just copy target to dentry | |
2098 | */ | |
2099 | memcpy(dentry->d_iname, target->d_name.name, | |
2100 | target->d_name.len + 1); | |
dc711ca3 AV |
2101 | dentry->d_name.len = target->d_name.len; |
2102 | return; | |
1da177e4 LT |
2103 | } |
2104 | } | |
9a8d5bb4 | 2105 | swap(dentry->d_name.len, target->d_name.len); |
1da177e4 LT |
2106 | } |
2107 | ||
2fd6b7f5 NP |
2108 | static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target) |
2109 | { | |
2110 | /* | |
2111 | * XXXX: do we really need to take target->d_lock? | |
2112 | */ | |
2113 | if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent) | |
2114 | spin_lock(&target->d_parent->d_lock); | |
2115 | else { | |
2116 | if (d_ancestor(dentry->d_parent, target->d_parent)) { | |
2117 | spin_lock(&dentry->d_parent->d_lock); | |
2118 | spin_lock_nested(&target->d_parent->d_lock, | |
2119 | DENTRY_D_LOCK_NESTED); | |
2120 | } else { | |
2121 | spin_lock(&target->d_parent->d_lock); | |
2122 | spin_lock_nested(&dentry->d_parent->d_lock, | |
2123 | DENTRY_D_LOCK_NESTED); | |
2124 | } | |
2125 | } | |
2126 | if (target < dentry) { | |
2127 | spin_lock_nested(&target->d_lock, 2); | |
2128 | spin_lock_nested(&dentry->d_lock, 3); | |
2129 | } else { | |
2130 | spin_lock_nested(&dentry->d_lock, 2); | |
2131 | spin_lock_nested(&target->d_lock, 3); | |
2132 | } | |
2133 | } | |
2134 | ||
2135 | static void dentry_unlock_parents_for_move(struct dentry *dentry, | |
2136 | struct dentry *target) | |
2137 | { | |
2138 | if (target->d_parent != dentry->d_parent) | |
2139 | spin_unlock(&dentry->d_parent->d_lock); | |
2140 | if (target->d_parent != target) | |
2141 | spin_unlock(&target->d_parent->d_lock); | |
2142 | } | |
2143 | ||
1da177e4 | 2144 | /* |
2fd6b7f5 NP |
2145 | * When switching names, the actual string doesn't strictly have to |
2146 | * be preserved in the target - because we're dropping the target | |
2147 | * anyway. As such, we can just do a simple memcpy() to copy over | |
2148 | * the new name before we switch. | |
2149 | * | |
2150 | * Note that we have to be a lot more careful about getting the hash | |
2151 | * switched - we have to switch the hash value properly even if it | |
2152 | * then no longer matches the actual (corrupted) string of the target. | |
2153 | * The hash value has to match the hash queue that the dentry is on.. | |
1da177e4 | 2154 | */ |
9eaef27b | 2155 | /* |
18367501 | 2156 | * __d_move - move a dentry |
1da177e4 LT |
2157 | * @dentry: entry to move |
2158 | * @target: new dentry | |
2159 | * | |
2160 | * Update the dcache to reflect the move of a file name. Negative | |
c46c8877 JL |
2161 | * dcache entries should not be moved in this way. Caller must hold |
2162 | * rename_lock, the i_mutex of the source and target directories, | |
2163 | * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). | |
1da177e4 | 2164 | */ |
18367501 | 2165 | static void __d_move(struct dentry * dentry, struct dentry * target) |
1da177e4 | 2166 | { |
1da177e4 LT |
2167 | if (!dentry->d_inode) |
2168 | printk(KERN_WARNING "VFS: moving negative dcache entry\n"); | |
2169 | ||
2fd6b7f5 NP |
2170 | BUG_ON(d_ancestor(dentry, target)); |
2171 | BUG_ON(d_ancestor(target, dentry)); | |
2172 | ||
2fd6b7f5 | 2173 | dentry_lock_for_move(dentry, target); |
1da177e4 | 2174 | |
31e6b01f NP |
2175 | write_seqcount_begin(&dentry->d_seq); |
2176 | write_seqcount_begin(&target->d_seq); | |
2177 | ||
ceb5bdc2 NP |
2178 | /* __d_drop does write_seqcount_barrier, but they're OK to nest. */ |
2179 | ||
2180 | /* | |
2181 | * Move the dentry to the target hash queue. Don't bother checking | |
2182 | * for the same hash queue because of how unlikely it is. | |
2183 | */ | |
2184 | __d_drop(dentry); | |
789680d1 | 2185 | __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); |
1da177e4 LT |
2186 | |
2187 | /* Unhash the target: dput() will then get rid of it */ | |
2188 | __d_drop(target); | |
2189 | ||
5160ee6f ED |
2190 | list_del(&dentry->d_u.d_child); |
2191 | list_del(&target->d_u.d_child); | |
1da177e4 LT |
2192 | |
2193 | /* Switch the names.. */ | |
2194 | switch_names(dentry, target); | |
9a8d5bb4 | 2195 | swap(dentry->d_name.hash, target->d_name.hash); |
1da177e4 LT |
2196 | |
2197 | /* ... and switch the parents */ | |
2198 | if (IS_ROOT(dentry)) { | |
2199 | dentry->d_parent = target->d_parent; | |
2200 | target->d_parent = target; | |
5160ee6f | 2201 | INIT_LIST_HEAD(&target->d_u.d_child); |
1da177e4 | 2202 | } else { |
9a8d5bb4 | 2203 | swap(dentry->d_parent, target->d_parent); |
1da177e4 LT |
2204 | |
2205 | /* And add them back to the (new) parent lists */ | |
5160ee6f | 2206 | list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); |
1da177e4 LT |
2207 | } |
2208 | ||
5160ee6f | 2209 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); |
2fd6b7f5 | 2210 | |
31e6b01f NP |
2211 | write_seqcount_end(&target->d_seq); |
2212 | write_seqcount_end(&dentry->d_seq); | |
2213 | ||
2fd6b7f5 | 2214 | dentry_unlock_parents_for_move(dentry, target); |
1da177e4 | 2215 | spin_unlock(&target->d_lock); |
c32ccd87 | 2216 | fsnotify_d_move(dentry); |
1da177e4 | 2217 | spin_unlock(&dentry->d_lock); |
18367501 AV |
2218 | } |
2219 | ||
2220 | /* | |
2221 | * d_move - move a dentry | |
2222 | * @dentry: entry to move | |
2223 | * @target: new dentry | |
2224 | * | |
2225 | * Update the dcache to reflect the move of a file name. Negative | |
c46c8877 JL |
2226 | * dcache entries should not be moved in this way. See the locking |
2227 | * requirements for __d_move. | |
18367501 AV |
2228 | */ |
2229 | void d_move(struct dentry *dentry, struct dentry *target) | |
2230 | { | |
2231 | write_seqlock(&rename_lock); | |
2232 | __d_move(dentry, target); | |
1da177e4 | 2233 | write_sequnlock(&rename_lock); |
9eaef27b | 2234 | } |
ec4f8605 | 2235 | EXPORT_SYMBOL(d_move); |
1da177e4 | 2236 | |
e2761a11 OH |
2237 | /** |
2238 | * d_ancestor - search for an ancestor | |
2239 | * @p1: ancestor dentry | |
2240 | * @p2: child dentry | |
2241 | * | |
2242 | * Returns the ancestor dentry of p2 which is a child of p1, if p1 is | |
2243 | * an ancestor of p2, else NULL. | |
9eaef27b | 2244 | */ |
e2761a11 | 2245 | struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) |
9eaef27b TM |
2246 | { |
2247 | struct dentry *p; | |
2248 | ||
871c0067 | 2249 | for (p = p2; !IS_ROOT(p); p = p->d_parent) { |
9eaef27b | 2250 | if (p->d_parent == p1) |
e2761a11 | 2251 | return p; |
9eaef27b | 2252 | } |
e2761a11 | 2253 | return NULL; |
9eaef27b TM |
2254 | } |
2255 | ||
2256 | /* | |
2257 | * This helper attempts to cope with remotely renamed directories | |
2258 | * | |
2259 | * It assumes that the caller is already holding | |
18367501 | 2260 | * dentry->d_parent->d_inode->i_mutex, inode->i_lock and rename_lock |
9eaef27b TM |
2261 | * |
2262 | * Note: If ever the locking in lock_rename() changes, then please | |
2263 | * remember to update this too... | |
9eaef27b | 2264 | */ |
873feea0 NP |
2265 | static struct dentry *__d_unalias(struct inode *inode, |
2266 | struct dentry *dentry, struct dentry *alias) | |
9eaef27b TM |
2267 | { |
2268 | struct mutex *m1 = NULL, *m2 = NULL; | |
2269 | struct dentry *ret; | |
2270 | ||
2271 | /* If alias and dentry share a parent, then no extra locks required */ | |
2272 | if (alias->d_parent == dentry->d_parent) | |
2273 | goto out_unalias; | |
2274 | ||
9eaef27b TM |
2275 | /* See lock_rename() */ |
2276 | ret = ERR_PTR(-EBUSY); | |
2277 | if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) | |
2278 | goto out_err; | |
2279 | m1 = &dentry->d_sb->s_vfs_rename_mutex; | |
2280 | if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex)) | |
2281 | goto out_err; | |
2282 | m2 = &alias->d_parent->d_inode->i_mutex; | |
2283 | out_unalias: | |
18367501 | 2284 | __d_move(alias, dentry); |
9eaef27b TM |
2285 | ret = alias; |
2286 | out_err: | |
873feea0 | 2287 | spin_unlock(&inode->i_lock); |
9eaef27b TM |
2288 | if (m2) |
2289 | mutex_unlock(m2); | |
2290 | if (m1) | |
2291 | mutex_unlock(m1); | |
2292 | return ret; | |
2293 | } | |
2294 | ||
770bfad8 DH |
2295 | /* |
2296 | * Prepare an anonymous dentry for life in the superblock's dentry tree as a | |
2297 | * named dentry in place of the dentry to be replaced. | |
2fd6b7f5 | 2298 | * returns with anon->d_lock held! |
770bfad8 DH |
2299 | */ |
2300 | static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) | |
2301 | { | |
2302 | struct dentry *dparent, *aparent; | |
2303 | ||
2fd6b7f5 | 2304 | dentry_lock_for_move(anon, dentry); |
770bfad8 | 2305 | |
31e6b01f NP |
2306 | write_seqcount_begin(&dentry->d_seq); |
2307 | write_seqcount_begin(&anon->d_seq); | |
2308 | ||
770bfad8 DH |
2309 | dparent = dentry->d_parent; |
2310 | aparent = anon->d_parent; | |
2311 | ||
2fd6b7f5 NP |
2312 | switch_names(dentry, anon); |
2313 | swap(dentry->d_name.hash, anon->d_name.hash); | |
2314 | ||
770bfad8 DH |
2315 | dentry->d_parent = (aparent == anon) ? dentry : aparent; |
2316 | list_del(&dentry->d_u.d_child); | |
2317 | if (!IS_ROOT(dentry)) | |
2318 | list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); | |
2319 | else | |
2320 | INIT_LIST_HEAD(&dentry->d_u.d_child); | |
2321 | ||
2322 | anon->d_parent = (dparent == dentry) ? anon : dparent; | |
2323 | list_del(&anon->d_u.d_child); | |
2324 | if (!IS_ROOT(anon)) | |
2325 | list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs); | |
2326 | else | |
2327 | INIT_LIST_HEAD(&anon->d_u.d_child); | |
2328 | ||
31e6b01f NP |
2329 | write_seqcount_end(&dentry->d_seq); |
2330 | write_seqcount_end(&anon->d_seq); | |
2331 | ||
2fd6b7f5 NP |
2332 | dentry_unlock_parents_for_move(anon, dentry); |
2333 | spin_unlock(&dentry->d_lock); | |
2334 | ||
2335 | /* anon->d_lock still locked, returns locked */ | |
770bfad8 DH |
2336 | anon->d_flags &= ~DCACHE_DISCONNECTED; |
2337 | } | |
2338 | ||
2339 | /** | |
2340 | * d_materialise_unique - introduce an inode into the tree | |
2341 | * @dentry: candidate dentry | |
2342 | * @inode: inode to bind to the dentry, to which aliases may be attached | |
2343 | * | |
2344 | * Introduces an dentry into the tree, substituting an extant disconnected | |
c46c8877 JL |
2345 | * root directory alias in its place if there is one. Caller must hold the |
2346 | * i_mutex of the parent directory. | |
770bfad8 DH |
2347 | */ |
2348 | struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) | |
2349 | { | |
9eaef27b | 2350 | struct dentry *actual; |
770bfad8 DH |
2351 | |
2352 | BUG_ON(!d_unhashed(dentry)); | |
2353 | ||
770bfad8 DH |
2354 | if (!inode) { |
2355 | actual = dentry; | |
360da900 | 2356 | __d_instantiate(dentry, NULL); |
357f8e65 NP |
2357 | d_rehash(actual); |
2358 | goto out_nolock; | |
770bfad8 DH |
2359 | } |
2360 | ||
873feea0 | 2361 | spin_lock(&inode->i_lock); |
357f8e65 | 2362 | |
9eaef27b TM |
2363 | if (S_ISDIR(inode->i_mode)) { |
2364 | struct dentry *alias; | |
2365 | ||
2366 | /* Does an aliased dentry already exist? */ | |
2367 | alias = __d_find_alias(inode, 0); | |
2368 | if (alias) { | |
2369 | actual = alias; | |
18367501 AV |
2370 | write_seqlock(&rename_lock); |
2371 | ||
2372 | if (d_ancestor(alias, dentry)) { | |
2373 | /* Check for loops */ | |
2374 | actual = ERR_PTR(-ELOOP); | |
2375 | } else if (IS_ROOT(alias)) { | |
2376 | /* Is this an anonymous mountpoint that we | |
2377 | * could splice into our tree? */ | |
9eaef27b | 2378 | __d_materialise_dentry(dentry, alias); |
18367501 | 2379 | write_sequnlock(&rename_lock); |
9eaef27b TM |
2380 | __d_drop(alias); |
2381 | goto found; | |
18367501 AV |
2382 | } else { |
2383 | /* Nope, but we must(!) avoid directory | |
2384 | * aliasing */ | |
2385 | actual = __d_unalias(inode, dentry, alias); | |
9eaef27b | 2386 | } |
18367501 | 2387 | write_sequnlock(&rename_lock); |
dd179946 DH |
2388 | if (IS_ERR(actual)) { |
2389 | if (PTR_ERR(actual) == -ELOOP) | |
2390 | pr_warn_ratelimited( | |
2391 | "VFS: Lookup of '%s' in %s %s" | |
2392 | " would have caused loop\n", | |
2393 | dentry->d_name.name, | |
2394 | inode->i_sb->s_type->name, | |
2395 | inode->i_sb->s_id); | |
9eaef27b | 2396 | dput(alias); |
dd179946 | 2397 | } |
9eaef27b TM |
2398 | goto out_nolock; |
2399 | } | |
770bfad8 DH |
2400 | } |
2401 | ||
2402 | /* Add a unique reference */ | |
2403 | actual = __d_instantiate_unique(dentry, inode); | |
2404 | if (!actual) | |
2405 | actual = dentry; | |
357f8e65 NP |
2406 | else |
2407 | BUG_ON(!d_unhashed(actual)); | |
770bfad8 | 2408 | |
770bfad8 DH |
2409 | spin_lock(&actual->d_lock); |
2410 | found: | |
2411 | _d_rehash(actual); | |
2412 | spin_unlock(&actual->d_lock); | |
873feea0 | 2413 | spin_unlock(&inode->i_lock); |
9eaef27b | 2414 | out_nolock: |
770bfad8 DH |
2415 | if (actual == dentry) { |
2416 | security_d_instantiate(dentry, inode); | |
2417 | return NULL; | |
2418 | } | |
2419 | ||
2420 | iput(inode); | |
2421 | return actual; | |
770bfad8 | 2422 | } |
ec4f8605 | 2423 | EXPORT_SYMBOL_GPL(d_materialise_unique); |
770bfad8 | 2424 | |
cdd16d02 | 2425 | static int prepend(char **buffer, int *buflen, const char *str, int namelen) |
6092d048 RP |
2426 | { |
2427 | *buflen -= namelen; | |
2428 | if (*buflen < 0) | |
2429 | return -ENAMETOOLONG; | |
2430 | *buffer -= namelen; | |
2431 | memcpy(*buffer, str, namelen); | |
2432 | return 0; | |
2433 | } | |
2434 | ||
cdd16d02 MS |
2435 | static int prepend_name(char **buffer, int *buflen, struct qstr *name) |
2436 | { | |
2437 | return prepend(buffer, buflen, name->name, name->len); | |
2438 | } | |
2439 | ||
1da177e4 | 2440 | /** |
208898c1 | 2441 | * prepend_path - Prepend path string to a buffer |
9d1bc601 | 2442 | * @path: the dentry/vfsmount to report |
02125a82 | 2443 | * @root: root vfsmnt/dentry |
f2eb6575 MS |
2444 | * @buffer: pointer to the end of the buffer |
2445 | * @buflen: pointer to buffer length | |
552ce544 | 2446 | * |
949854d0 | 2447 | * Caller holds the rename_lock. |
1da177e4 | 2448 | */ |
02125a82 AV |
2449 | static int prepend_path(const struct path *path, |
2450 | const struct path *root, | |
f2eb6575 | 2451 | char **buffer, int *buflen) |
1da177e4 | 2452 | { |
9d1bc601 MS |
2453 | struct dentry *dentry = path->dentry; |
2454 | struct vfsmount *vfsmnt = path->mnt; | |
0714a533 | 2455 | struct mount *mnt = real_mount(vfsmnt); |
f2eb6575 MS |
2456 | bool slash = false; |
2457 | int error = 0; | |
6092d048 | 2458 | |
99b7db7b | 2459 | br_read_lock(vfsmount_lock); |
f2eb6575 | 2460 | while (dentry != root->dentry || vfsmnt != root->mnt) { |
1da177e4 LT |
2461 | struct dentry * parent; |
2462 | ||
1da177e4 | 2463 | if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { |
552ce544 | 2464 | /* Global root? */ |
676da58d | 2465 | if (!mnt_has_parent(mnt)) |
1da177e4 | 2466 | goto global_root; |
a73324da | 2467 | dentry = mnt->mnt_mountpoint; |
0714a533 AV |
2468 | mnt = mnt->mnt_parent; |
2469 | vfsmnt = &mnt->mnt; | |
1da177e4 LT |
2470 | continue; |
2471 | } | |
2472 | parent = dentry->d_parent; | |
2473 | prefetch(parent); | |
9abca360 | 2474 | spin_lock(&dentry->d_lock); |
f2eb6575 | 2475 | error = prepend_name(buffer, buflen, &dentry->d_name); |
9abca360 | 2476 | spin_unlock(&dentry->d_lock); |
f2eb6575 MS |
2477 | if (!error) |
2478 | error = prepend(buffer, buflen, "/", 1); | |
2479 | if (error) | |
2480 | break; | |
2481 | ||
2482 | slash = true; | |
1da177e4 LT |
2483 | dentry = parent; |
2484 | } | |
2485 | ||
f2eb6575 MS |
2486 | if (!error && !slash) |
2487 | error = prepend(buffer, buflen, "/", 1); | |
2488 | ||
02125a82 | 2489 | out: |
99b7db7b | 2490 | br_read_unlock(vfsmount_lock); |
f2eb6575 | 2491 | return error; |
1da177e4 LT |
2492 | |
2493 | global_root: | |
98dc568b MS |
2494 | /* |
2495 | * Filesystems needing to implement special "root names" | |
2496 | * should do so with ->d_dname() | |
2497 | */ | |
2498 | if (IS_ROOT(dentry) && | |
2499 | (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { | |
2500 | WARN(1, "Root dentry has weird name <%.*s>\n", | |
2501 | (int) dentry->d_name.len, dentry->d_name.name); | |
2502 | } | |
02125a82 AV |
2503 | if (!slash) |
2504 | error = prepend(buffer, buflen, "/", 1); | |
2505 | if (!error) | |
143c8c91 | 2506 | error = real_mount(vfsmnt)->mnt_ns ? 1 : 2; |
be285c71 | 2507 | goto out; |
f2eb6575 | 2508 | } |
be285c71 | 2509 | |
f2eb6575 MS |
2510 | /** |
2511 | * __d_path - return the path of a dentry | |
2512 | * @path: the dentry/vfsmount to report | |
02125a82 | 2513 | * @root: root vfsmnt/dentry |
cd956a1c | 2514 | * @buf: buffer to return value in |
f2eb6575 MS |
2515 | * @buflen: buffer length |
2516 | * | |
ffd1f4ed | 2517 | * Convert a dentry into an ASCII path name. |
f2eb6575 MS |
2518 | * |
2519 | * Returns a pointer into the buffer or an error code if the | |
2520 | * path was too long. | |
2521 | * | |
be148247 | 2522 | * "buflen" should be positive. |
f2eb6575 | 2523 | * |
02125a82 | 2524 | * If the path is not reachable from the supplied root, return %NULL. |
f2eb6575 | 2525 | */ |
02125a82 AV |
2526 | char *__d_path(const struct path *path, |
2527 | const struct path *root, | |
f2eb6575 MS |
2528 | char *buf, int buflen) |
2529 | { | |
2530 | char *res = buf + buflen; | |
2531 | int error; | |
2532 | ||
2533 | prepend(&res, &buflen, "\0", 1); | |
949854d0 | 2534 | write_seqlock(&rename_lock); |
f2eb6575 | 2535 | error = prepend_path(path, root, &res, &buflen); |
949854d0 | 2536 | write_sequnlock(&rename_lock); |
be148247 | 2537 | |
02125a82 AV |
2538 | if (error < 0) |
2539 | return ERR_PTR(error); | |
2540 | if (error > 0) | |
2541 | return NULL; | |
2542 | return res; | |
2543 | } | |
2544 | ||
2545 | char *d_absolute_path(const struct path *path, | |
2546 | char *buf, int buflen) | |
2547 | { | |
2548 | struct path root = {}; | |
2549 | char *res = buf + buflen; | |
2550 | int error; | |
2551 | ||
2552 | prepend(&res, &buflen, "\0", 1); | |
2553 | write_seqlock(&rename_lock); | |
2554 | error = prepend_path(path, &root, &res, &buflen); | |
2555 | write_sequnlock(&rename_lock); | |
2556 | ||
2557 | if (error > 1) | |
2558 | error = -EINVAL; | |
2559 | if (error < 0) | |
f2eb6575 | 2560 | return ERR_PTR(error); |
f2eb6575 | 2561 | return res; |
1da177e4 LT |
2562 | } |
2563 | ||
ffd1f4ed MS |
2564 | /* |
2565 | * same as __d_path but appends "(deleted)" for unlinked files. | |
2566 | */ | |
02125a82 AV |
2567 | static int path_with_deleted(const struct path *path, |
2568 | const struct path *root, | |
2569 | char **buf, int *buflen) | |
ffd1f4ed MS |
2570 | { |
2571 | prepend(buf, buflen, "\0", 1); | |
2572 | if (d_unlinked(path->dentry)) { | |
2573 | int error = prepend(buf, buflen, " (deleted)", 10); | |
2574 | if (error) | |
2575 | return error; | |
2576 | } | |
2577 | ||
2578 | return prepend_path(path, root, buf, buflen); | |
2579 | } | |
2580 | ||
8df9d1a4 MS |
2581 | static int prepend_unreachable(char **buffer, int *buflen) |
2582 | { | |
2583 | return prepend(buffer, buflen, "(unreachable)", 13); | |
2584 | } | |
2585 | ||
a03a8a70 JB |
2586 | /** |
2587 | * d_path - return the path of a dentry | |
cf28b486 | 2588 | * @path: path to report |
a03a8a70 JB |
2589 | * @buf: buffer to return value in |
2590 | * @buflen: buffer length | |
2591 | * | |
2592 | * Convert a dentry into an ASCII path name. If the entry has been deleted | |
2593 | * the string " (deleted)" is appended. Note that this is ambiguous. | |
2594 | * | |
52afeefb AV |
2595 | * Returns a pointer into the buffer or an error code if the path was |
2596 | * too long. Note: Callers should use the returned pointer, not the passed | |
2597 | * in buffer, to use the name! The implementation often starts at an offset | |
2598 | * into the buffer, and may leave 0 bytes at the start. | |
a03a8a70 | 2599 | * |
31f3e0b3 | 2600 | * "buflen" should be positive. |
a03a8a70 | 2601 | */ |
20d4fdc1 | 2602 | char *d_path(const struct path *path, char *buf, int buflen) |
1da177e4 | 2603 | { |
ffd1f4ed | 2604 | char *res = buf + buflen; |
6ac08c39 | 2605 | struct path root; |
ffd1f4ed | 2606 | int error; |
1da177e4 | 2607 | |
c23fbb6b ED |
2608 | /* |
2609 | * We have various synthetic filesystems that never get mounted. On | |
2610 | * these filesystems dentries are never used for lookup purposes, and | |
2611 | * thus don't need to be hashed. They also don't need a name until a | |
2612 | * user wants to identify the object in /proc/pid/fd/. The little hack | |
2613 | * below allows us to generate a name for these objects on demand: | |
2614 | */ | |
cf28b486 JB |
2615 | if (path->dentry->d_op && path->dentry->d_op->d_dname) |
2616 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); | |
c23fbb6b | 2617 | |
f7ad3c6b | 2618 | get_fs_root(current->fs, &root); |
949854d0 | 2619 | write_seqlock(&rename_lock); |
02125a82 AV |
2620 | error = path_with_deleted(path, &root, &res, &buflen); |
2621 | if (error < 0) | |
ffd1f4ed | 2622 | res = ERR_PTR(error); |
949854d0 | 2623 | write_sequnlock(&rename_lock); |
6ac08c39 | 2624 | path_put(&root); |
1da177e4 LT |
2625 | return res; |
2626 | } | |
ec4f8605 | 2627 | EXPORT_SYMBOL(d_path); |
1da177e4 | 2628 | |
8df9d1a4 MS |
2629 | /** |
2630 | * d_path_with_unreachable - return the path of a dentry | |
2631 | * @path: path to report | |
2632 | * @buf: buffer to return value in | |
2633 | * @buflen: buffer length | |
2634 | * | |
2635 | * The difference from d_path() is that this prepends "(unreachable)" | |
2636 | * to paths which are unreachable from the current process' root. | |
2637 | */ | |
2638 | char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) | |
2639 | { | |
2640 | char *res = buf + buflen; | |
2641 | struct path root; | |
8df9d1a4 MS |
2642 | int error; |
2643 | ||
2644 | if (path->dentry->d_op && path->dentry->d_op->d_dname) | |
2645 | return path->dentry->d_op->d_dname(path->dentry, buf, buflen); | |
2646 | ||
2647 | get_fs_root(current->fs, &root); | |
949854d0 | 2648 | write_seqlock(&rename_lock); |
02125a82 AV |
2649 | error = path_with_deleted(path, &root, &res, &buflen); |
2650 | if (error > 0) | |
8df9d1a4 | 2651 | error = prepend_unreachable(&res, &buflen); |
949854d0 | 2652 | write_sequnlock(&rename_lock); |
8df9d1a4 MS |
2653 | path_put(&root); |
2654 | if (error) | |
2655 | res = ERR_PTR(error); | |
2656 | ||
2657 | return res; | |
2658 | } | |
2659 | ||
c23fbb6b ED |
2660 | /* |
2661 | * Helper function for dentry_operations.d_dname() members | |
2662 | */ | |
2663 | char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, | |
2664 | const char *fmt, ...) | |
2665 | { | |
2666 | va_list args; | |
2667 | char temp[64]; | |
2668 | int sz; | |
2669 | ||
2670 | va_start(args, fmt); | |
2671 | sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1; | |
2672 | va_end(args); | |
2673 | ||
2674 | if (sz > sizeof(temp) || sz > buflen) | |
2675 | return ERR_PTR(-ENAMETOOLONG); | |
2676 | ||
2677 | buffer += buflen - sz; | |
2678 | return memcpy(buffer, temp, sz); | |
2679 | } | |
2680 | ||
6092d048 RP |
2681 | /* |
2682 | * Write full pathname from the root of the filesystem into the buffer. | |
2683 | */ | |
ec2447c2 | 2684 | static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) |
6092d048 RP |
2685 | { |
2686 | char *end = buf + buflen; | |
2687 | char *retval; | |
2688 | ||
6092d048 | 2689 | prepend(&end, &buflen, "\0", 1); |
6092d048 RP |
2690 | if (buflen < 1) |
2691 | goto Elong; | |
2692 | /* Get '/' right */ | |
2693 | retval = end-1; | |
2694 | *retval = '/'; | |
2695 | ||
cdd16d02 MS |
2696 | while (!IS_ROOT(dentry)) { |
2697 | struct dentry *parent = dentry->d_parent; | |
9abca360 | 2698 | int error; |
6092d048 | 2699 | |
6092d048 | 2700 | prefetch(parent); |
9abca360 NP |
2701 | spin_lock(&dentry->d_lock); |
2702 | error = prepend_name(&end, &buflen, &dentry->d_name); | |
2703 | spin_unlock(&dentry->d_lock); | |
2704 | if (error != 0 || prepend(&end, &buflen, "/", 1) != 0) | |
6092d048 RP |
2705 | goto Elong; |
2706 | ||
2707 | retval = end; | |
2708 | dentry = parent; | |
2709 | } | |
c103135c AV |
2710 | return retval; |
2711 | Elong: | |
2712 | return ERR_PTR(-ENAMETOOLONG); | |
2713 | } | |
ec2447c2 NP |
2714 | |
2715 | char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen) | |
2716 | { | |
2717 | char *retval; | |
2718 | ||
949854d0 | 2719 | write_seqlock(&rename_lock); |
ec2447c2 | 2720 | retval = __dentry_path(dentry, buf, buflen); |
949854d0 | 2721 | write_sequnlock(&rename_lock); |
ec2447c2 NP |
2722 | |
2723 | return retval; | |
2724 | } | |
2725 | EXPORT_SYMBOL(dentry_path_raw); | |
c103135c AV |
2726 | |
2727 | char *dentry_path(struct dentry *dentry, char *buf, int buflen) | |
2728 | { | |
2729 | char *p = NULL; | |
2730 | char *retval; | |
2731 | ||
949854d0 | 2732 | write_seqlock(&rename_lock); |
c103135c AV |
2733 | if (d_unlinked(dentry)) { |
2734 | p = buf + buflen; | |
2735 | if (prepend(&p, &buflen, "//deleted", 10) != 0) | |
2736 | goto Elong; | |
2737 | buflen++; | |
2738 | } | |
2739 | retval = __dentry_path(dentry, buf, buflen); | |
949854d0 | 2740 | write_sequnlock(&rename_lock); |
c103135c AV |
2741 | if (!IS_ERR(retval) && p) |
2742 | *p = '/'; /* restore '/' overriden with '\0' */ | |
6092d048 RP |
2743 | return retval; |
2744 | Elong: | |
6092d048 RP |
2745 | return ERR_PTR(-ENAMETOOLONG); |
2746 | } | |
2747 | ||
1da177e4 LT |
2748 | /* |
2749 | * NOTE! The user-level library version returns a | |
2750 | * character pointer. The kernel system call just | |
2751 | * returns the length of the buffer filled (which | |
2752 | * includes the ending '\0' character), or a negative | |
2753 | * error value. So libc would do something like | |
2754 | * | |
2755 | * char *getcwd(char * buf, size_t size) | |
2756 | * { | |
2757 | * int retval; | |
2758 | * | |
2759 | * retval = sys_getcwd(buf, size); | |
2760 | * if (retval >= 0) | |
2761 | * return buf; | |
2762 | * errno = -retval; | |
2763 | * return NULL; | |
2764 | * } | |
2765 | */ | |
3cdad428 | 2766 | SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) |
1da177e4 | 2767 | { |
552ce544 | 2768 | int error; |
6ac08c39 | 2769 | struct path pwd, root; |
552ce544 | 2770 | char *page = (char *) __get_free_page(GFP_USER); |
1da177e4 LT |
2771 | |
2772 | if (!page) | |
2773 | return -ENOMEM; | |
2774 | ||
f7ad3c6b | 2775 | get_fs_root_and_pwd(current->fs, &root, &pwd); |
1da177e4 | 2776 | |
552ce544 | 2777 | error = -ENOENT; |
949854d0 | 2778 | write_seqlock(&rename_lock); |
f3da392e | 2779 | if (!d_unlinked(pwd.dentry)) { |
552ce544 | 2780 | unsigned long len; |
8df9d1a4 MS |
2781 | char *cwd = page + PAGE_SIZE; |
2782 | int buflen = PAGE_SIZE; | |
1da177e4 | 2783 | |
8df9d1a4 | 2784 | prepend(&cwd, &buflen, "\0", 1); |
02125a82 | 2785 | error = prepend_path(&pwd, &root, &cwd, &buflen); |
949854d0 | 2786 | write_sequnlock(&rename_lock); |
552ce544 | 2787 | |
02125a82 | 2788 | if (error < 0) |
552ce544 LT |
2789 | goto out; |
2790 | ||
8df9d1a4 | 2791 | /* Unreachable from current root */ |
02125a82 | 2792 | if (error > 0) { |
8df9d1a4 MS |
2793 | error = prepend_unreachable(&cwd, &buflen); |
2794 | if (error) | |
2795 | goto out; | |
2796 | } | |
2797 | ||
552ce544 LT |
2798 | error = -ERANGE; |
2799 | len = PAGE_SIZE + page - cwd; | |
2800 | if (len <= size) { | |
2801 | error = len; | |
2802 | if (copy_to_user(buf, cwd, len)) | |
2803 | error = -EFAULT; | |
2804 | } | |
949854d0 NP |
2805 | } else { |
2806 | write_sequnlock(&rename_lock); | |
949854d0 | 2807 | } |
1da177e4 LT |
2808 | |
2809 | out: | |
6ac08c39 JB |
2810 | path_put(&pwd); |
2811 | path_put(&root); | |
1da177e4 LT |
2812 | free_page((unsigned long) page); |
2813 | return error; | |
2814 | } | |
2815 | ||
2816 | /* | |
2817 | * Test whether new_dentry is a subdirectory of old_dentry. | |
2818 | * | |
2819 | * Trivially implemented using the dcache structure | |
2820 | */ | |
2821 | ||
2822 | /** | |
2823 | * is_subdir - is new dentry a subdirectory of old_dentry | |
2824 | * @new_dentry: new dentry | |
2825 | * @old_dentry: old dentry | |
2826 | * | |
2827 | * Returns 1 if new_dentry is a subdirectory of the parent (at any depth). | |
2828 | * Returns 0 otherwise. | |
2829 | * Caller must ensure that "new_dentry" is pinned before calling is_subdir() | |
2830 | */ | |
2831 | ||
e2761a11 | 2832 | int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) |
1da177e4 LT |
2833 | { |
2834 | int result; | |
949854d0 | 2835 | unsigned seq; |
1da177e4 | 2836 | |
e2761a11 OH |
2837 | if (new_dentry == old_dentry) |
2838 | return 1; | |
2839 | ||
e2761a11 | 2840 | do { |
1da177e4 | 2841 | /* for restarting inner loop in case of seq retry */ |
1da177e4 | 2842 | seq = read_seqbegin(&rename_lock); |
949854d0 NP |
2843 | /* |
2844 | * Need rcu_readlock to protect against the d_parent trashing | |
2845 | * due to d_move | |
2846 | */ | |
2847 | rcu_read_lock(); | |
e2761a11 | 2848 | if (d_ancestor(old_dentry, new_dentry)) |
1da177e4 | 2849 | result = 1; |
e2761a11 OH |
2850 | else |
2851 | result = 0; | |
949854d0 | 2852 | rcu_read_unlock(); |
1da177e4 | 2853 | } while (read_seqretry(&rename_lock, seq)); |
1da177e4 LT |
2854 | |
2855 | return result; | |
2856 | } | |
2857 | ||
2858 | void d_genocide(struct dentry *root) | |
2859 | { | |
949854d0 | 2860 | struct dentry *this_parent; |
1da177e4 | 2861 | struct list_head *next; |
949854d0 | 2862 | unsigned seq; |
58db63d0 | 2863 | int locked = 0; |
1da177e4 | 2864 | |
949854d0 | 2865 | seq = read_seqbegin(&rename_lock); |
58db63d0 NP |
2866 | again: |
2867 | this_parent = root; | |
2fd6b7f5 | 2868 | spin_lock(&this_parent->d_lock); |
1da177e4 LT |
2869 | repeat: |
2870 | next = this_parent->d_subdirs.next; | |
2871 | resume: | |
2872 | while (next != &this_parent->d_subdirs) { | |
2873 | struct list_head *tmp = next; | |
5160ee6f | 2874 | struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); |
1da177e4 | 2875 | next = tmp->next; |
949854d0 | 2876 | |
da502956 NP |
2877 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
2878 | if (d_unhashed(dentry) || !dentry->d_inode) { | |
2879 | spin_unlock(&dentry->d_lock); | |
1da177e4 | 2880 | continue; |
da502956 | 2881 | } |
1da177e4 | 2882 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
2883 | spin_unlock(&this_parent->d_lock); |
2884 | spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); | |
1da177e4 | 2885 | this_parent = dentry; |
2fd6b7f5 | 2886 | spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); |
1da177e4 LT |
2887 | goto repeat; |
2888 | } | |
949854d0 NP |
2889 | if (!(dentry->d_flags & DCACHE_GENOCIDE)) { |
2890 | dentry->d_flags |= DCACHE_GENOCIDE; | |
2891 | dentry->d_count--; | |
2892 | } | |
b7ab39f6 | 2893 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
2894 | } |
2895 | if (this_parent != root) { | |
c826cb7d | 2896 | struct dentry *child = this_parent; |
949854d0 NP |
2897 | if (!(this_parent->d_flags & DCACHE_GENOCIDE)) { |
2898 | this_parent->d_flags |= DCACHE_GENOCIDE; | |
2899 | this_parent->d_count--; | |
2900 | } | |
c826cb7d LT |
2901 | this_parent = try_to_ascend(this_parent, locked, seq); |
2902 | if (!this_parent) | |
949854d0 | 2903 | goto rename_retry; |
949854d0 | 2904 | next = child->d_u.d_child.next; |
1da177e4 LT |
2905 | goto resume; |
2906 | } | |
2fd6b7f5 | 2907 | spin_unlock(&this_parent->d_lock); |
58db63d0 | 2908 | if (!locked && read_seqretry(&rename_lock, seq)) |
949854d0 | 2909 | goto rename_retry; |
58db63d0 NP |
2910 | if (locked) |
2911 | write_sequnlock(&rename_lock); | |
2912 | return; | |
2913 | ||
2914 | rename_retry: | |
2915 | locked = 1; | |
2916 | write_seqlock(&rename_lock); | |
2917 | goto again; | |
1da177e4 LT |
2918 | } |
2919 | ||
2920 | /** | |
2921 | * find_inode_number - check for dentry with name | |
2922 | * @dir: directory to check | |
2923 | * @name: Name to find. | |
2924 | * | |
2925 | * Check whether a dentry already exists for the given name, | |
2926 | * and return the inode number if it has an inode. Otherwise | |
2927 | * 0 is returned. | |
2928 | * | |
2929 | * This routine is used to post-process directory listings for | |
2930 | * filesystems using synthetic inode numbers, and is necessary | |
2931 | * to keep getcwd() working. | |
2932 | */ | |
2933 | ||
2934 | ino_t find_inode_number(struct dentry *dir, struct qstr *name) | |
2935 | { | |
2936 | struct dentry * dentry; | |
2937 | ino_t ino = 0; | |
2938 | ||
3e7e241f EB |
2939 | dentry = d_hash_and_lookup(dir, name); |
2940 | if (dentry) { | |
1da177e4 LT |
2941 | if (dentry->d_inode) |
2942 | ino = dentry->d_inode->i_ino; | |
2943 | dput(dentry); | |
2944 | } | |
1da177e4 LT |
2945 | return ino; |
2946 | } | |
ec4f8605 | 2947 | EXPORT_SYMBOL(find_inode_number); |
1da177e4 LT |
2948 | |
2949 | static __initdata unsigned long dhash_entries; | |
2950 | static int __init set_dhash_entries(char *str) | |
2951 | { | |
2952 | if (!str) | |
2953 | return 0; | |
2954 | dhash_entries = simple_strtoul(str, &str, 0); | |
2955 | return 1; | |
2956 | } | |
2957 | __setup("dhash_entries=", set_dhash_entries); | |
2958 | ||
2959 | static void __init dcache_init_early(void) | |
2960 | { | |
2961 | int loop; | |
2962 | ||
2963 | /* If hashes are distributed across NUMA nodes, defer | |
2964 | * hash allocation until vmalloc space is available. | |
2965 | */ | |
2966 | if (hashdist) | |
2967 | return; | |
2968 | ||
2969 | dentry_hashtable = | |
2970 | alloc_large_system_hash("Dentry cache", | |
b07ad996 | 2971 | sizeof(struct hlist_bl_head), |
1da177e4 LT |
2972 | dhash_entries, |
2973 | 13, | |
2974 | HASH_EARLY, | |
2975 | &d_hash_shift, | |
2976 | &d_hash_mask, | |
2977 | 0); | |
2978 | ||
2979 | for (loop = 0; loop < (1 << d_hash_shift); loop++) | |
b07ad996 | 2980 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
1da177e4 LT |
2981 | } |
2982 | ||
74bf17cf | 2983 | static void __init dcache_init(void) |
1da177e4 LT |
2984 | { |
2985 | int loop; | |
2986 | ||
2987 | /* | |
2988 | * A constructor could be added for stable state like the lists, | |
2989 | * but it is probably not worth it because of the cache nature | |
2990 | * of the dcache. | |
2991 | */ | |
0a31bd5f CL |
2992 | dentry_cache = KMEM_CACHE(dentry, |
2993 | SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD); | |
1da177e4 LT |
2994 | |
2995 | /* Hash may have been set up in dcache_init_early */ | |
2996 | if (!hashdist) | |
2997 | return; | |
2998 | ||
2999 | dentry_hashtable = | |
3000 | alloc_large_system_hash("Dentry cache", | |
b07ad996 | 3001 | sizeof(struct hlist_bl_head), |
1da177e4 LT |
3002 | dhash_entries, |
3003 | 13, | |
3004 | 0, | |
3005 | &d_hash_shift, | |
3006 | &d_hash_mask, | |
3007 | 0); | |
3008 | ||
3009 | for (loop = 0; loop < (1 << d_hash_shift); loop++) | |
b07ad996 | 3010 | INIT_HLIST_BL_HEAD(dentry_hashtable + loop); |
1da177e4 LT |
3011 | } |
3012 | ||
3013 | /* SLAB cache for __getname() consumers */ | |
e18b890b | 3014 | struct kmem_cache *names_cachep __read_mostly; |
ec4f8605 | 3015 | EXPORT_SYMBOL(names_cachep); |
1da177e4 | 3016 | |
1da177e4 LT |
3017 | EXPORT_SYMBOL(d_genocide); |
3018 | ||
1da177e4 LT |
3019 | void __init vfs_caches_init_early(void) |
3020 | { | |
3021 | dcache_init_early(); | |
3022 | inode_init_early(); | |
3023 | } | |
3024 | ||
3025 | void __init vfs_caches_init(unsigned long mempages) | |
3026 | { | |
3027 | unsigned long reserve; | |
3028 | ||
3029 | /* Base hash sizes on available memory, with a reserve equal to | |
3030 | 150% of current kernel size */ | |
3031 | ||
3032 | reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1); | |
3033 | mempages -= reserve; | |
3034 | ||
3035 | names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0, | |
20c2df83 | 3036 | SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
1da177e4 | 3037 | |
74bf17cf DC |
3038 | dcache_init(); |
3039 | inode_init(); | |
1da177e4 | 3040 | files_init(mempages); |
74bf17cf | 3041 | mnt_init(); |
1da177e4 LT |
3042 | bdev_cache_init(); |
3043 | chrdev_init(); | |
3044 | } |