blob: 9f04e1ba75b7f5fa7d2362647d69043b1a0ae831 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/syscalls.h>
18#include <linux/string.h>
19#include <linux/mm.h>
20#include <linux/fs.h>
John McCutchan7a91bf72005-08-08 13:52:16 -040021#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/slab.h>
23#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#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>
Al Viro5ad4e532009-03-29 19:50:06 -040034#include <linux/fs_struct.h>
Frederic Weisbecker613afbf2009-07-16 15:44:29 +020035#include <linux/hardirq.h>
Nick Pigginceb5bdc2011-01-07 17:50:05 +110036#include <linux/bit_spinlock.h>
37#include <linux/rculist_bl.h>
David Howells07f3f052006-09-30 20:52:18 +020038#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Nick Piggin789680d2011-01-07 17:49:30 +110040/*
41 * Usage:
Nick Pigginb23fb0a2011-01-07 17:49:35 +110042 * dcache_inode_lock protects:
43 * - i_dentry, d_alias, d_inode
Nick Pigginceb5bdc2011-01-07 17:50:05 +110044 * dcache_hash_bucket lock protects:
45 * - the dcache hash table
46 * s_anon bl list spinlock protects:
47 * - the s_anon list (see __d_drop)
Nick Piggin23044502011-01-07 17:49:31 +110048 * dcache_lru_lock protects:
49 * - the dcache lru lists and counters
50 * d_lock protects:
51 * - d_flags
52 * - d_name
53 * - d_lru
Nick Pigginb7ab39f2011-01-07 17:49:32 +110054 * - d_count
Nick Pigginda502952011-01-07 17:49:33 +110055 * - d_unhashed()
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110056 * - d_parent and d_subdirs
57 * - childrens' d_child and d_parent
Nick Pigginb23fb0a2011-01-07 17:49:35 +110058 * - d_alias, d_inode
Nick Piggin789680d2011-01-07 17:49:30 +110059 *
60 * Ordering:
Nick Pigginb5c84bf2011-01-07 17:49:38 +110061 * dcache_inode_lock
62 * dentry->d_lock
63 * dcache_lru_lock
Nick Pigginceb5bdc2011-01-07 17:50:05 +110064 * dcache_hash_bucket lock
65 * s_anon lock
Nick Piggin789680d2011-01-07 17:49:30 +110066 *
Nick Pigginda502952011-01-07 17:49:33 +110067 * If there is an ancestor relationship:
68 * dentry->d_parent->...->d_parent->d_lock
69 * ...
70 * dentry->d_parent->d_lock
71 * dentry->d_lock
72 *
73 * If no ancestor relationship:
Nick Piggin789680d2011-01-07 17:49:30 +110074 * if (dentry1 < dentry2)
75 * dentry1->d_lock
76 * dentry2->d_lock
77 */
Eric Dumazetfa3536c2006-03-26 01:37:24 -080078int sysctl_vfs_cache_pressure __read_mostly = 100;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
80
Nick Pigginb23fb0a2011-01-07 17:49:35 +110081__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_inode_lock);
Nick Piggin23044502011-01-07 17:49:31 +110082static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock);
Al Viro74c3cbe2007-07-22 08:04:18 -040083__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Nick Piggin949854d2011-01-07 17:49:37 +110085EXPORT_SYMBOL(rename_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +110086EXPORT_SYMBOL(dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
Christoph Lametere18b8902006-12-06 20:33:20 -080088static struct kmem_cache *dentry_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
Linus Torvalds1da177e2005-04-16 15:20:36 -070090/*
91 * This is the single most critical data structure when it comes
92 * to the dcache: the hashtable for lookups. Somebody should try
93 * to make this good - I've just made it work.
94 *
95 * This hash-function tries to avoid losing too many bits of hash
96 * information, yet avoid using a prime hash-size or similar.
97 */
98#define D_HASHBITS d_hash_shift
99#define D_HASHMASK d_hash_mask
100
Eric Dumazetfa3536c2006-03-26 01:37:24 -0800101static unsigned int d_hash_mask __read_mostly;
102static unsigned int d_hash_shift __read_mostly;
Nick Pigginceb5bdc2011-01-07 17:50:05 +1100103
104struct dcache_hash_bucket {
105 struct hlist_bl_head head;
106};
107static struct dcache_hash_bucket *dentry_hashtable __read_mostly;
108
109static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
110 unsigned long hash)
111{
112 hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
113 hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
114 return dentry_hashtable + (hash & D_HASHMASK);
115}
116
117static inline void spin_lock_bucket(struct dcache_hash_bucket *b)
118{
119 bit_spin_lock(0, (unsigned long *)&b->head.first);
120}
121
122static inline void spin_unlock_bucket(struct dcache_hash_bucket *b)
123{
124 __bit_spin_unlock(0, (unsigned long *)&b->head.first);
125}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
127/* Statistics gathering. */
128struct dentry_stat_t dentry_stat = {
129 .age_limit = 45,
130};
131
Nick Piggin3e880fb2011-01-07 17:49:19 +1100132static DEFINE_PER_CPU(unsigned int, nr_dentry);
Christoph Hellwig312d3ca2010-10-10 05:36:23 -0400133
134#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
Nick Piggin3e880fb2011-01-07 17:49:19 +1100135static int get_nr_dentry(void)
136{
137 int i;
138 int sum = 0;
139 for_each_possible_cpu(i)
140 sum += per_cpu(nr_dentry, i);
141 return sum < 0 ? 0 : sum;
142}
143
Christoph Hellwig312d3ca2010-10-10 05:36:23 -0400144int proc_nr_dentry(ctl_table *table, int write, void __user *buffer,
145 size_t *lenp, loff_t *ppos)
146{
Nick Piggin3e880fb2011-01-07 17:49:19 +1100147 dentry_stat.nr_dentry = get_nr_dentry();
Christoph Hellwig312d3ca2010-10-10 05:36:23 -0400148 return proc_dointvec(table, write, buffer, lenp, ppos);
149}
150#endif
151
Christoph Hellwig9c82ab92010-10-10 05:36:22 -0400152static void __d_free(struct rcu_head *head)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153{
Christoph Hellwig9c82ab92010-10-10 05:36:22 -0400154 struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
155
Arjan van de Venfd217f42008-10-21 06:47:33 -0700156 WARN_ON(!list_empty(&dentry->d_alias));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 if (dname_external(dentry))
158 kfree(dentry->d_name.name);
159 kmem_cache_free(dentry_cache, dentry);
160}
161
162/*
Nick Pigginb5c84bf2011-01-07 17:49:38 +1100163 * no locks, please.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 */
165static void d_free(struct dentry *dentry)
166{
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100167 BUG_ON(dentry->d_count);
Nick Piggin3e880fb2011-01-07 17:49:19 +1100168 this_cpu_dec(nr_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 if (dentry->d_op && dentry->d_op->d_release)
170 dentry->d_op->d_release(dentry);
Christoph Hellwig312d3ca2010-10-10 05:36:23 -0400171
Eric Dumazetb3423412006-12-06 20:38:48 -0800172 /* if dentry was never inserted into hash, immediate free is OK */
Nick Pigginceb5bdc2011-01-07 17:50:05 +1100173 if (hlist_bl_unhashed(&dentry->d_hash))
Christoph Hellwig9c82ab92010-10-10 05:36:22 -0400174 __d_free(&dentry->d_u.d_rcu);
Eric Dumazetb3423412006-12-06 20:38:48 -0800175 else
Christoph Hellwig9c82ab92010-10-10 05:36:22 -0400176 call_rcu(&dentry->d_u.d_rcu, __d_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177}
178
Nick Piggin31e6b012011-01-07 17:49:52 +1100179/**
180 * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups
181 * After this call, in-progress rcu-walk path lookup will fail. This
182 * should be called after unhashing, and after changing d_inode (if
183 * the dentry has not already been unhashed).
184 */
185static inline void dentry_rcuwalk_barrier(struct dentry *dentry)
186{
187 assert_spin_locked(&dentry->d_lock);
188 /* Go through a barrier */
189 write_seqcount_barrier(&dentry->d_seq);
190}
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192/*
193 * Release the dentry's inode, using the filesystem
Nick Piggin31e6b012011-01-07 17:49:52 +1100194 * d_iput() operation if defined. Dentry has no refcount
195 * and is unhashed.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800197static void dentry_iput(struct dentry * dentry)
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +0200198 __releases(dentry->d_lock)
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100199 __releases(dcache_inode_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
201 struct inode *inode = dentry->d_inode;
202 if (inode) {
203 dentry->d_inode = NULL;
204 list_del_init(&dentry->d_alias);
205 spin_unlock(&dentry->d_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100206 spin_unlock(&dcache_inode_lock);
Linus Torvaldsf805fbd2005-09-19 19:54:29 -0700207 if (!inode->i_nlink)
208 fsnotify_inoderemove(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 if (dentry->d_op && dentry->d_op->d_iput)
210 dentry->d_op->d_iput(dentry, inode);
211 else
212 iput(inode);
213 } else {
214 spin_unlock(&dentry->d_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100215 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 }
217}
218
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700219/*
Nick Piggin31e6b012011-01-07 17:49:52 +1100220 * Release the dentry's inode, using the filesystem
221 * d_iput() operation if defined. dentry remains in-use.
222 */
223static void dentry_unlink_inode(struct dentry * dentry)
224 __releases(dentry->d_lock)
225 __releases(dcache_inode_lock)
226{
227 struct inode *inode = dentry->d_inode;
228 dentry->d_inode = NULL;
229 list_del_init(&dentry->d_alias);
230 dentry_rcuwalk_barrier(dentry);
231 spin_unlock(&dentry->d_lock);
232 spin_unlock(&dcache_inode_lock);
233 if (!inode->i_nlink)
234 fsnotify_inoderemove(inode);
235 if (dentry->d_op && dentry->d_op->d_iput)
236 dentry->d_op->d_iput(dentry, inode);
237 else
238 iput(inode);
239}
240
241/*
Nick Piggin23044502011-01-07 17:49:31 +1100242 * dentry_lru_(add|del|move_tail) must be called with d_lock held.
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700243 */
244static void dentry_lru_add(struct dentry *dentry)
245{
Christoph Hellwiga4633352010-10-10 05:36:26 -0400246 if (list_empty(&dentry->d_lru)) {
Nick Piggin23044502011-01-07 17:49:31 +1100247 spin_lock(&dcache_lru_lock);
Christoph Hellwiga4633352010-10-10 05:36:26 -0400248 list_add(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
249 dentry->d_sb->s_nr_dentry_unused++;
Nick Piggin86c87492011-01-07 17:49:18 +1100250 dentry_stat.nr_unused++;
Nick Piggin23044502011-01-07 17:49:31 +1100251 spin_unlock(&dcache_lru_lock);
Christoph Hellwiga4633352010-10-10 05:36:26 -0400252 }
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700253}
254
Nick Piggin23044502011-01-07 17:49:31 +1100255static void __dentry_lru_del(struct dentry *dentry)
256{
257 list_del_init(&dentry->d_lru);
258 dentry->d_sb->s_nr_dentry_unused--;
259 dentry_stat.nr_unused--;
260}
261
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700262static void dentry_lru_del(struct dentry *dentry)
263{
264 if (!list_empty(&dentry->d_lru)) {
Nick Piggin23044502011-01-07 17:49:31 +1100265 spin_lock(&dcache_lru_lock);
266 __dentry_lru_del(dentry);
267 spin_unlock(&dcache_lru_lock);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700268 }
269}
270
Christoph Hellwiga4633352010-10-10 05:36:26 -0400271static void dentry_lru_move_tail(struct dentry *dentry)
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700272{
Nick Piggin23044502011-01-07 17:49:31 +1100273 spin_lock(&dcache_lru_lock);
Christoph Hellwiga4633352010-10-10 05:36:26 -0400274 if (list_empty(&dentry->d_lru)) {
275 list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
276 dentry->d_sb->s_nr_dentry_unused++;
Nick Piggin86c87492011-01-07 17:49:18 +1100277 dentry_stat.nr_unused++;
Christoph Hellwiga4633352010-10-10 05:36:26 -0400278 } else {
279 list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700280 }
Nick Piggin23044502011-01-07 17:49:31 +1100281 spin_unlock(&dcache_lru_lock);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700282}
283
Miklos Szeredid52b9082007-05-08 00:23:46 -0700284/**
285 * d_kill - kill dentry and return parent
286 * @dentry: dentry to kill
287 *
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +0200288 * The dentry must already be unhashed and removed from the LRU.
Miklos Szeredid52b9082007-05-08 00:23:46 -0700289 *
290 * If this is the root of the dentry tree, return NULL.
Nick Piggin23044502011-01-07 17:49:31 +1100291 *
Nick Pigginb5c84bf2011-01-07 17:49:38 +1100292 * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by
293 * d_kill.
Miklos Szeredid52b9082007-05-08 00:23:46 -0700294 */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100295static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +0200296 __releases(dentry->d_lock)
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100297 __releases(parent->d_lock)
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100298 __releases(dcache_inode_lock)
Miklos Szeredid52b9082007-05-08 00:23:46 -0700299{
Nick Piggin949854d2011-01-07 17:49:37 +1100300 dentry->d_parent = NULL;
Miklos Szeredid52b9082007-05-08 00:23:46 -0700301 list_del(&dentry->d_u.d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100302 if (parent)
303 spin_unlock(&parent->d_lock);
Miklos Szeredid52b9082007-05-08 00:23:46 -0700304 dentry_iput(dentry);
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100305 /*
306 * dentry_iput drops the locks, at which point nobody (except
307 * transient RCU lookups) can reach this dentry.
308 */
Miklos Szeredid52b9082007-05-08 00:23:46 -0700309 d_free(dentry);
OGAWA Hirofumi871c0062008-10-16 07:50:27 +0900310 return parent;
Miklos Szeredid52b9082007-05-08 00:23:46 -0700311}
312
Nick Piggin789680d2011-01-07 17:49:30 +1100313/**
314 * d_drop - drop a dentry
315 * @dentry: dentry to drop
316 *
317 * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
318 * be found through a VFS lookup any more. Note that this is different from
319 * deleting the dentry - d_delete will try to mark the dentry negative if
320 * possible, giving a successful _negative_ lookup, while d_drop will
321 * just make the cache lookup fail.
322 *
323 * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
324 * reason (NFS timeouts or autofs deletes).
325 *
326 * __d_drop requires dentry->d_lock.
327 */
328void __d_drop(struct dentry *dentry)
329{
330 if (!(dentry->d_flags & DCACHE_UNHASHED)) {
Nick Pigginceb5bdc2011-01-07 17:50:05 +1100331 if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) {
332 bit_spin_lock(0,
333 (unsigned long *)&dentry->d_sb->s_anon.first);
334 dentry->d_flags |= DCACHE_UNHASHED;
335 hlist_bl_del_init(&dentry->d_hash);
336 __bit_spin_unlock(0,
337 (unsigned long *)&dentry->d_sb->s_anon.first);
338 } else {
339 struct dcache_hash_bucket *b;
340 b = d_hash(dentry->d_parent, dentry->d_name.hash);
341 spin_lock_bucket(b);
342 /*
343 * We may not actually need to put DCACHE_UNHASHED
344 * manipulations under the hash lock, but follow
345 * the principle of least surprise.
346 */
347 dentry->d_flags |= DCACHE_UNHASHED;
348 hlist_bl_del_rcu(&dentry->d_hash);
349 spin_unlock_bucket(b);
350 dentry_rcuwalk_barrier(dentry);
351 }
Nick Piggin789680d2011-01-07 17:49:30 +1100352 }
353}
354EXPORT_SYMBOL(__d_drop);
355
356void d_drop(struct dentry *dentry)
357{
Nick Piggin789680d2011-01-07 17:49:30 +1100358 spin_lock(&dentry->d_lock);
359 __d_drop(dentry);
360 spin_unlock(&dentry->d_lock);
Nick Piggin789680d2011-01-07 17:49:30 +1100361}
362EXPORT_SYMBOL(d_drop);
363
Nick Piggin77812a12011-01-07 17:49:48 +1100364/*
365 * Finish off a dentry we've decided to kill.
366 * dentry->d_lock must be held, returns with it unlocked.
367 * If ref is non-zero, then decrement the refcount too.
368 * Returns dentry requiring refcount drop, or NULL if we're done.
369 */
370static inline struct dentry *dentry_kill(struct dentry *dentry, int ref)
371 __releases(dentry->d_lock)
372{
373 struct dentry *parent;
374
375 if (!spin_trylock(&dcache_inode_lock)) {
376relock:
377 spin_unlock(&dentry->d_lock);
378 cpu_relax();
379 return dentry; /* try again with same dentry */
380 }
381 if (IS_ROOT(dentry))
382 parent = NULL;
383 else
384 parent = dentry->d_parent;
385 if (parent && !spin_trylock(&parent->d_lock)) {
386 spin_unlock(&dcache_inode_lock);
387 goto relock;
388 }
Nick Piggin31e6b012011-01-07 17:49:52 +1100389
Nick Piggin77812a12011-01-07 17:49:48 +1100390 if (ref)
391 dentry->d_count--;
392 /* if dentry was on the d_lru list delete it from there */
393 dentry_lru_del(dentry);
394 /* if it was on the hash then remove it */
395 __d_drop(dentry);
396 return d_kill(dentry, parent);
397}
398
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399/*
400 * This is dput
401 *
402 * This is complicated by the fact that we do not want to put
403 * dentries that are no longer on any hash chain on the unused
404 * list: we'd much rather just get rid of them immediately.
405 *
406 * However, that implies that we have to traverse the dentry
407 * tree upwards to the parents which might _also_ now be
408 * scheduled for deletion (it may have been only waiting for
409 * its last child to go away).
410 *
411 * This tail recursion is done by hand as we don't want to depend
412 * on the compiler to always get this right (gcc generally doesn't).
413 * Real recursion would eat up our stack space.
414 */
415
416/*
417 * dput - release a dentry
418 * @dentry: dentry to release
419 *
420 * Release a dentry. This will drop the usage count and if appropriate
421 * call the dentry unlink method as well as removing it from the queues and
422 * releasing its resources. If the parent dentries were scheduled for release
423 * they too may now get deleted.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425void dput(struct dentry *dentry)
426{
427 if (!dentry)
428 return;
429
430repeat:
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100431 if (dentry->d_count == 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 spin_lock(&dentry->d_lock);
Nick Piggin61f3dee2011-01-07 17:49:40 +1100434 BUG_ON(!dentry->d_count);
435 if (dentry->d_count > 1) {
436 dentry->d_count--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 return;
439 }
440
Nick Pigginfb045ad2011-01-07 17:49:55 +1100441 if (dentry->d_flags & DCACHE_OP_DELETE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 if (dentry->d_op->d_delete(dentry))
Nick Piggin61f3dee2011-01-07 17:49:40 +1100443 goto kill_it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 }
Nick Piggin265ac902010-10-10 05:36:24 -0400445
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 /* Unreachable? Get rid of it */
447 if (d_unhashed(dentry))
448 goto kill_it;
Nick Piggin265ac902010-10-10 05:36:24 -0400449
450 /* Otherwise leave it cached and ensure it's on the LRU */
451 dentry->d_flags |= DCACHE_REFERENCED;
Christoph Hellwiga4633352010-10-10 05:36:26 -0400452 dentry_lru_add(dentry);
Nick Piggin265ac902010-10-10 05:36:24 -0400453
Nick Piggin61f3dee2011-01-07 17:49:40 +1100454 dentry->d_count--;
455 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 return;
457
Miklos Szeredid52b9082007-05-08 00:23:46 -0700458kill_it:
Nick Piggin77812a12011-01-07 17:49:48 +1100459 dentry = dentry_kill(dentry, 1);
Miklos Szeredid52b9082007-05-08 00:23:46 -0700460 if (dentry)
461 goto repeat;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -0700463EXPORT_SYMBOL(dput);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
465/**
466 * d_invalidate - invalidate a dentry
467 * @dentry: dentry to invalidate
468 *
469 * Try to invalidate the dentry if it turns out to be
470 * possible. If there are other dentries that can be
471 * reached through this one we can't delete it and we
472 * return -EBUSY. On success we return 0.
473 *
474 * no dcache lock.
475 */
476
477int d_invalidate(struct dentry * dentry)
478{
479 /*
480 * If it's already been dropped, return OK.
481 */
Nick Pigginda502952011-01-07 17:49:33 +1100482 spin_lock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 if (d_unhashed(dentry)) {
Nick Pigginda502952011-01-07 17:49:33 +1100484 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 return 0;
486 }
487 /*
488 * Check whether to do a partial shrink_dcache
489 * to get rid of unused child entries.
490 */
491 if (!list_empty(&dentry->d_subdirs)) {
Nick Pigginda502952011-01-07 17:49:33 +1100492 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 shrink_dcache_parent(dentry);
Nick Pigginda502952011-01-07 17:49:33 +1100494 spin_lock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 }
496
497 /*
498 * Somebody else still using it?
499 *
500 * If it's a directory, we can't drop it
501 * for fear of somebody re-populating it
502 * with children (even though dropping it
503 * would make it unreachable from the root,
504 * we might still populate it if it was a
505 * working directory or similar).
506 */
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100507 if (dentry->d_count > 1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) {
509 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 return -EBUSY;
511 }
512 }
513
514 __d_drop(dentry);
515 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 return 0;
517}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -0700518EXPORT_SYMBOL(d_invalidate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519
Nick Pigginb5c84bf2011-01-07 17:49:38 +1100520/* This must be called with d_lock held */
Nick Piggindc0474b2011-01-07 17:49:43 +1100521static inline void __dget_dlock(struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522{
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100523 dentry->d_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524}
525
Nick Piggindc0474b2011-01-07 17:49:43 +1100526static inline void __dget(struct dentry *dentry)
Nick Piggin23044502011-01-07 17:49:31 +1100527{
Nick Piggin23044502011-01-07 17:49:31 +1100528 spin_lock(&dentry->d_lock);
Nick Piggindc0474b2011-01-07 17:49:43 +1100529 __dget_dlock(dentry);
Nick Piggin23044502011-01-07 17:49:31 +1100530 spin_unlock(&dentry->d_lock);
Nick Piggin23044502011-01-07 17:49:31 +1100531}
532
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100533struct dentry *dget_parent(struct dentry *dentry)
534{
535 struct dentry *ret;
536
537repeat:
Nick Piggina734eb42011-01-07 17:49:44 +1100538 /*
539 * Don't need rcu_dereference because we re-check it was correct under
540 * the lock.
541 */
542 rcu_read_lock();
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100543 ret = dentry->d_parent;
Nick Piggina734eb42011-01-07 17:49:44 +1100544 if (!ret) {
545 rcu_read_unlock();
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100546 goto out;
547 }
Nick Piggina734eb42011-01-07 17:49:44 +1100548 spin_lock(&ret->d_lock);
549 if (unlikely(ret != dentry->d_parent)) {
550 spin_unlock(&ret->d_lock);
551 rcu_read_unlock();
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100552 goto repeat;
553 }
Nick Piggina734eb42011-01-07 17:49:44 +1100554 rcu_read_unlock();
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100555 BUG_ON(!ret->d_count);
556 ret->d_count++;
557 spin_unlock(&ret->d_lock);
558out:
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100559 return ret;
560}
561EXPORT_SYMBOL(dget_parent);
562
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563/**
564 * d_find_alias - grab a hashed alias of inode
565 * @inode: inode in question
566 * @want_discon: flag, used by d_splice_alias, to request
567 * that only a DISCONNECTED alias be returned.
568 *
569 * If inode has a hashed alias, or is a directory and has any alias,
570 * acquire the reference to alias and return it. Otherwise return NULL.
571 * Notice that if inode is a directory there can be only one alias and
572 * it can be unhashed only if it has no children, or if it is the root
573 * of a filesystem.
574 *
NeilBrown21c0d8f2006-10-04 02:16:16 -0700575 * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 * any other hashed alias over that one unless @want_discon is set,
NeilBrown21c0d8f2006-10-04 02:16:16 -0700577 * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 */
Nick Pigginda502952011-01-07 17:49:33 +1100579static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
Nick Pigginda502952011-01-07 17:49:33 +1100581 struct dentry *alias, *discon_alias;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582
Nick Pigginda502952011-01-07 17:49:33 +1100583again:
584 discon_alias = NULL;
585 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
586 spin_lock(&alias->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
NeilBrown21c0d8f2006-10-04 02:16:16 -0700588 if (IS_ROOT(alias) &&
Nick Pigginda502952011-01-07 17:49:33 +1100589 (alias->d_flags & DCACHE_DISCONNECTED)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 discon_alias = alias;
Nick Pigginda502952011-01-07 17:49:33 +1100591 } else if (!want_discon) {
Nick Piggindc0474b2011-01-07 17:49:43 +1100592 __dget_dlock(alias);
Nick Pigginda502952011-01-07 17:49:33 +1100593 spin_unlock(&alias->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 return alias;
595 }
596 }
Nick Pigginda502952011-01-07 17:49:33 +1100597 spin_unlock(&alias->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 }
Nick Pigginda502952011-01-07 17:49:33 +1100599 if (discon_alias) {
600 alias = discon_alias;
601 spin_lock(&alias->d_lock);
602 if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
603 if (IS_ROOT(alias) &&
604 (alias->d_flags & DCACHE_DISCONNECTED)) {
Nick Piggindc0474b2011-01-07 17:49:43 +1100605 __dget_dlock(alias);
Nick Pigginda502952011-01-07 17:49:33 +1100606 spin_unlock(&alias->d_lock);
607 return alias;
608 }
609 }
610 spin_unlock(&alias->d_lock);
611 goto again;
612 }
613 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614}
615
Nick Pigginda502952011-01-07 17:49:33 +1100616struct dentry *d_find_alias(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617{
David Howells214fda12006-03-25 03:06:36 -0800618 struct dentry *de = NULL;
619
620 if (!list_empty(&inode->i_dentry)) {
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100621 spin_lock(&dcache_inode_lock);
David Howells214fda12006-03-25 03:06:36 -0800622 de = __d_find_alias(inode, 0);
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100623 spin_unlock(&dcache_inode_lock);
David Howells214fda12006-03-25 03:06:36 -0800624 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 return de;
626}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -0700627EXPORT_SYMBOL(d_find_alias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
629/*
630 * Try to kill dentries associated with this inode.
631 * WARNING: you must own a reference to inode.
632 */
633void d_prune_aliases(struct inode *inode)
634{
Domen Puncer0cdca3f2005-09-10 00:27:07 -0700635 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636restart:
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100637 spin_lock(&dcache_inode_lock);
Domen Puncer0cdca3f2005-09-10 00:27:07 -0700638 list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 spin_lock(&dentry->d_lock);
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100640 if (!dentry->d_count) {
Nick Piggindc0474b2011-01-07 17:49:43 +1100641 __dget_dlock(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 __d_drop(dentry);
643 spin_unlock(&dentry->d_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100644 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 dput(dentry);
646 goto restart;
647 }
648 spin_unlock(&dentry->d_lock);
649 }
Nick Pigginb23fb0a2011-01-07 17:49:35 +1100650 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -0700652EXPORT_SYMBOL(d_prune_aliases);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
654/*
Nick Piggin77812a12011-01-07 17:49:48 +1100655 * Try to throw away a dentry - free the inode, dput the parent.
656 * Requires dentry->d_lock is held, and dentry->d_count == 0.
657 * Releases dentry->d_lock.
Andrew Mortond702ccb2006-06-22 14:47:31 -0700658 *
Nick Piggin77812a12011-01-07 17:49:48 +1100659 * This may fail if locks cannot be acquired no problem, just try again.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 */
Nick Piggin77812a12011-01-07 17:49:48 +1100661static void try_prune_one_dentry(struct dentry *dentry)
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +0200662 __releases(dentry->d_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663{
Nick Piggin77812a12011-01-07 17:49:48 +1100664 struct dentry *parent;
Miklos Szeredid52b9082007-05-08 00:23:46 -0700665
Nick Piggin77812a12011-01-07 17:49:48 +1100666 parent = dentry_kill(dentry, 0);
Miklos Szeredid52b9082007-05-08 00:23:46 -0700667 /*
Nick Piggin77812a12011-01-07 17:49:48 +1100668 * If dentry_kill returns NULL, we have nothing more to do.
669 * if it returns the same dentry, trylocks failed. In either
670 * case, just loop again.
671 *
672 * Otherwise, we need to prune ancestors too. This is necessary
673 * to prevent quadratic behavior of shrink_dcache_parent(), but
674 * is also expected to be beneficial in reducing dentry cache
675 * fragmentation.
Miklos Szeredid52b9082007-05-08 00:23:46 -0700676 */
Nick Piggin77812a12011-01-07 17:49:48 +1100677 if (!parent)
678 return;
679 if (parent == dentry)
680 return;
681
682 /* Prune ancestors. */
683 dentry = parent;
Miklos Szeredid52b9082007-05-08 00:23:46 -0700684 while (dentry) {
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100685 spin_lock(&dentry->d_lock);
Nick Piggin89e60542011-01-07 17:49:45 +1100686 if (dentry->d_count > 1) {
687 dentry->d_count--;
688 spin_unlock(&dentry->d_lock);
689 return;
690 }
Nick Piggin77812a12011-01-07 17:49:48 +1100691 dentry = dentry_kill(dentry, 1);
Miklos Szeredid52b9082007-05-08 00:23:46 -0700692 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693}
694
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400695static void shrink_dentry_list(struct list_head *list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696{
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700697 struct dentry *dentry;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700698
Nick Pigginec336792011-01-07 17:49:47 +1100699 rcu_read_lock();
700 for (;;) {
Nick Pigginec336792011-01-07 17:49:47 +1100701 dentry = list_entry_rcu(list->prev, struct dentry, d_lru);
702 if (&dentry->d_lru == list)
703 break; /* empty */
704 spin_lock(&dentry->d_lock);
705 if (dentry != list_entry(list->prev, struct dentry, d_lru)) {
706 spin_unlock(&dentry->d_lock);
Nick Piggin23044502011-01-07 17:49:31 +1100707 continue;
708 }
709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 /*
711 * We found an inuse dentry which was not removed from
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700712 * the LRU because of laziness during lookup. Do not free
713 * it - just keep it off the LRU list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 */
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100715 if (dentry->d_count) {
Nick Pigginec336792011-01-07 17:49:47 +1100716 dentry_lru_del(dentry);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700717 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 continue;
719 }
Nick Pigginec336792011-01-07 17:49:47 +1100720
Nick Pigginec336792011-01-07 17:49:47 +1100721 rcu_read_unlock();
Nick Piggin77812a12011-01-07 17:49:48 +1100722
723 try_prune_one_dentry(dentry);
724
Nick Pigginec336792011-01-07 17:49:47 +1100725 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 }
Nick Pigginec336792011-01-07 17:49:47 +1100727 rcu_read_unlock();
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400728}
729
730/**
731 * __shrink_dcache_sb - shrink the dentry LRU on a given superblock
732 * @sb: superblock to shrink dentry LRU.
733 * @count: number of entries to prune
734 * @flags: flags to control the dentry processing
735 *
736 * If flags contains DCACHE_REFERENCED reference dentries will not be pruned.
737 */
738static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
739{
740 /* called from prune_dcache() and shrink_dcache_parent() */
741 struct dentry *dentry;
742 LIST_HEAD(referenced);
743 LIST_HEAD(tmp);
744 int cnt = *count;
745
Nick Piggin23044502011-01-07 17:49:31 +1100746relock:
747 spin_lock(&dcache_lru_lock);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400748 while (!list_empty(&sb->s_dentry_lru)) {
749 dentry = list_entry(sb->s_dentry_lru.prev,
750 struct dentry, d_lru);
751 BUG_ON(dentry->d_sb != sb);
752
Nick Piggin23044502011-01-07 17:49:31 +1100753 if (!spin_trylock(&dentry->d_lock)) {
754 spin_unlock(&dcache_lru_lock);
755 cpu_relax();
756 goto relock;
757 }
758
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400759 /*
760 * If we are honouring the DCACHE_REFERENCED flag and the
761 * dentry has this flag set, don't free it. Clear the flag
762 * and put it back on the LRU.
763 */
Nick Piggin23044502011-01-07 17:49:31 +1100764 if (flags & DCACHE_REFERENCED &&
765 dentry->d_flags & DCACHE_REFERENCED) {
766 dentry->d_flags &= ~DCACHE_REFERENCED;
767 list_move(&dentry->d_lru, &referenced);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400768 spin_unlock(&dentry->d_lock);
Nick Piggin23044502011-01-07 17:49:31 +1100769 } else {
770 list_move_tail(&dentry->d_lru, &tmp);
771 spin_unlock(&dentry->d_lock);
772 if (!--cnt)
773 break;
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400774 }
Nick Pigginec336792011-01-07 17:49:47 +1100775 cond_resched_lock(&dcache_lru_lock);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400776 }
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700777 if (!list_empty(&referenced))
778 list_splice(&referenced, &sb->s_dentry_lru);
Nick Piggin23044502011-01-07 17:49:31 +1100779 spin_unlock(&dcache_lru_lock);
Nick Pigginec336792011-01-07 17:49:47 +1100780
781 shrink_dentry_list(&tmp);
782
783 *count = cnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784}
785
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700786/**
787 * prune_dcache - shrink the dcache
788 * @count: number of entries to try to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 *
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700790 * Shrink the dcache. This is done when we need more memory, or simply when we
791 * need to unmount something (at which point we need to unuse all dentries).
792 *
793 * This function may fail to free any resources if all the dentries are in use.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 */
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700795static void prune_dcache(int count)
796{
Al Virodca33252010-07-25 02:31:46 +0400797 struct super_block *sb, *p = NULL;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700798 int w_count;
Nick Piggin86c87492011-01-07 17:49:18 +1100799 int unused = dentry_stat.nr_unused;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700800 int prune_ratio;
801 int pruned;
802
803 if (unused == 0 || count == 0)
804 return;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700805 if (count >= unused)
806 prune_ratio = 1;
807 else
808 prune_ratio = unused / count;
809 spin_lock(&sb_lock);
Al Virodca33252010-07-25 02:31:46 +0400810 list_for_each_entry(sb, &super_blocks, s_list) {
Al Viro551de6f2010-03-22 19:36:35 -0400811 if (list_empty(&sb->s_instances))
812 continue;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700813 if (sb->s_nr_dentry_unused == 0)
814 continue;
815 sb->s_count++;
816 /* Now, we reclaim unused dentrins with fairness.
817 * We reclaim them same percentage from each superblock.
818 * We calculate number of dentries to scan on this sb
819 * as follows, but the implementation is arranged to avoid
820 * overflows:
821 * number of dentries to scan on this sb =
822 * count * (number of dentries on this sb /
823 * number of dentries in the machine)
824 */
825 spin_unlock(&sb_lock);
826 if (prune_ratio != 1)
827 w_count = (sb->s_nr_dentry_unused / prune_ratio) + 1;
828 else
829 w_count = sb->s_nr_dentry_unused;
830 pruned = w_count;
831 /*
832 * We need to be sure this filesystem isn't being unmounted,
833 * otherwise we could race with generic_shutdown_super(), and
834 * end up holding a reference to an inode while the filesystem
835 * is unmounted. So we try to get s_umount, and make sure
836 * s_root isn't NULL.
837 */
838 if (down_read_trylock(&sb->s_umount)) {
839 if ((sb->s_root != NULL) &&
840 (!list_empty(&sb->s_dentry_lru))) {
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700841 __shrink_dcache_sb(sb, &w_count,
842 DCACHE_REFERENCED);
843 pruned -= w_count;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700844 }
845 up_read(&sb->s_umount);
846 }
847 spin_lock(&sb_lock);
Al Virodca33252010-07-25 02:31:46 +0400848 if (p)
849 __put_super(p);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700850 count -= pruned;
Al Virodca33252010-07-25 02:31:46 +0400851 p = sb;
Al Viro79893c12010-03-22 20:27:55 -0400852 /* more work left to do? */
853 if (count <= 0)
854 break;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700855 }
Al Virodca33252010-07-25 02:31:46 +0400856 if (p)
857 __put_super(p);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700858 spin_unlock(&sb_lock);
Kentaro Makitada3bbdd2008-07-23 21:27:13 -0700859}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860
861/**
862 * shrink_dcache_sb - shrink dcache for a superblock
863 * @sb: superblock
864 *
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400865 * Shrink the dcache for the specified super block. This is used to free
866 * the dcache before unmounting a file system.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 */
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400868void shrink_dcache_sb(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869{
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400870 LIST_HEAD(tmp);
871
Nick Piggin23044502011-01-07 17:49:31 +1100872 spin_lock(&dcache_lru_lock);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400873 while (!list_empty(&sb->s_dentry_lru)) {
874 list_splice_init(&sb->s_dentry_lru, &tmp);
Nick Pigginec336792011-01-07 17:49:47 +1100875 spin_unlock(&dcache_lru_lock);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400876 shrink_dentry_list(&tmp);
Nick Pigginec336792011-01-07 17:49:47 +1100877 spin_lock(&dcache_lru_lock);
Christoph Hellwig3049cfe2010-10-10 05:36:25 -0400878 }
Nick Piggin23044502011-01-07 17:49:31 +1100879 spin_unlock(&dcache_lru_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -0700881EXPORT_SYMBOL(shrink_dcache_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882
883/*
David Howellsc636ebd2006-10-11 01:22:19 -0700884 * destroy a single subtree of dentries for unmount
885 * - see the comments on shrink_dcache_for_umount() for a description of the
886 * locking
887 */
888static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
889{
890 struct dentry *parent;
David Howellsf8713572006-10-28 10:38:46 -0700891 unsigned detached = 0;
David Howellsc636ebd2006-10-11 01:22:19 -0700892
893 BUG_ON(!IS_ROOT(dentry));
894
895 /* detach this root from the system */
Nick Piggin23044502011-01-07 17:49:31 +1100896 spin_lock(&dentry->d_lock);
Christoph Hellwiga4633352010-10-10 05:36:26 -0400897 dentry_lru_del(dentry);
David Howellsc636ebd2006-10-11 01:22:19 -0700898 __d_drop(dentry);
Nick Pigginda502952011-01-07 17:49:33 +1100899 spin_unlock(&dentry->d_lock);
David Howellsc636ebd2006-10-11 01:22:19 -0700900
901 for (;;) {
902 /* descend to the first leaf in the current subtree */
903 while (!list_empty(&dentry->d_subdirs)) {
904 struct dentry *loop;
905
906 /* this is a branch with children - detach all of them
907 * from the system in one go */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100908 spin_lock(&dentry->d_lock);
David Howellsc636ebd2006-10-11 01:22:19 -0700909 list_for_each_entry(loop, &dentry->d_subdirs,
910 d_u.d_child) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100911 spin_lock_nested(&loop->d_lock,
912 DENTRY_D_LOCK_NESTED);
Christoph Hellwiga4633352010-10-10 05:36:26 -0400913 dentry_lru_del(loop);
David Howellsc636ebd2006-10-11 01:22:19 -0700914 __d_drop(loop);
Nick Pigginda502952011-01-07 17:49:33 +1100915 spin_unlock(&loop->d_lock);
David Howellsc636ebd2006-10-11 01:22:19 -0700916 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100917 spin_unlock(&dentry->d_lock);
David Howellsc636ebd2006-10-11 01:22:19 -0700918
919 /* move to the first child */
920 dentry = list_entry(dentry->d_subdirs.next,
921 struct dentry, d_u.d_child);
922 }
923
924 /* consume the dentries from this leaf up through its parents
925 * until we find one with children or run out altogether */
926 do {
927 struct inode *inode;
928
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100929 if (dentry->d_count != 0) {
David Howellsc636ebd2006-10-11 01:22:19 -0700930 printk(KERN_ERR
931 "BUG: Dentry %p{i=%lx,n=%s}"
932 " still in use (%d)"
933 " [unmount of %s %s]\n",
934 dentry,
935 dentry->d_inode ?
936 dentry->d_inode->i_ino : 0UL,
937 dentry->d_name.name,
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100938 dentry->d_count,
David Howellsc636ebd2006-10-11 01:22:19 -0700939 dentry->d_sb->s_type->name,
940 dentry->d_sb->s_id);
941 BUG();
942 }
943
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100944 if (IS_ROOT(dentry)) {
David Howellsc636ebd2006-10-11 01:22:19 -0700945 parent = NULL;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100946 list_del(&dentry->d_u.d_child);
947 } else {
OGAWA Hirofumi871c0062008-10-16 07:50:27 +0900948 parent = dentry->d_parent;
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100949 spin_lock(&parent->d_lock);
950 parent->d_count--;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100951 list_del(&dentry->d_u.d_child);
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100952 spin_unlock(&parent->d_lock);
OGAWA Hirofumi871c0062008-10-16 07:50:27 +0900953 }
David Howellsc636ebd2006-10-11 01:22:19 -0700954
David Howellsf8713572006-10-28 10:38:46 -0700955 detached++;
David Howellsc636ebd2006-10-11 01:22:19 -0700956
957 inode = dentry->d_inode;
958 if (inode) {
959 dentry->d_inode = NULL;
960 list_del_init(&dentry->d_alias);
961 if (dentry->d_op && dentry->d_op->d_iput)
962 dentry->d_op->d_iput(dentry, inode);
963 else
964 iput(inode);
965 }
966
967 d_free(dentry);
968
969 /* finished when we fall off the top of the tree,
970 * otherwise we ascend to the parent and move to the
971 * next sibling if there is one */
972 if (!parent)
Christoph Hellwig312d3ca2010-10-10 05:36:23 -0400973 return;
David Howellsc636ebd2006-10-11 01:22:19 -0700974 dentry = parent;
David Howellsc636ebd2006-10-11 01:22:19 -0700975 } while (list_empty(&dentry->d_subdirs));
976
977 dentry = list_entry(dentry->d_subdirs.next,
978 struct dentry, d_u.d_child);
979 }
980}
981
982/*
983 * destroy the dentries attached to a superblock on unmounting
Nick Pigginb5c84bf2011-01-07 17:49:38 +1100984 * - we don't need to use dentry->d_lock because:
David Howellsc636ebd2006-10-11 01:22:19 -0700985 * - the superblock is detached from all mountings and open files, so the
986 * dentry trees will not be rearranged by the VFS
987 * - s_umount is write-locked, so the memory pressure shrinker will ignore
988 * any dentries belonging to this superblock that it comes across
989 * - the filesystem itself is no longer permitted to rearrange the dentries
990 * in this superblock
991 */
992void shrink_dcache_for_umount(struct super_block *sb)
993{
994 struct dentry *dentry;
995
996 if (down_read_trylock(&sb->s_umount))
997 BUG();
998
999 dentry = sb->s_root;
1000 sb->s_root = NULL;
Nick Pigginb7ab39f2011-01-07 17:49:32 +11001001 spin_lock(&dentry->d_lock);
1002 dentry->d_count--;
1003 spin_unlock(&dentry->d_lock);
David Howellsc636ebd2006-10-11 01:22:19 -07001004 shrink_dcache_for_umount_subtree(dentry);
1005
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001006 while (!hlist_bl_empty(&sb->s_anon)) {
1007 dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash);
David Howellsc636ebd2006-10-11 01:22:19 -07001008 shrink_dcache_for_umount_subtree(dentry);
1009 }
1010}
1011
1012/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 * Search for at least 1 mount point in the dentry's subdirs.
1014 * We descend to the next level whenever the d_subdirs
1015 * list is non-empty and continue searching.
1016 */
1017
1018/**
1019 * have_submounts - check for mounts over a dentry
1020 * @parent: dentry to check.
1021 *
1022 * Return true if the parent or its subdirectories contain
1023 * a mount point
1024 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025int have_submounts(struct dentry *parent)
1026{
Nick Piggin949854d2011-01-07 17:49:37 +11001027 struct dentry *this_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 struct list_head *next;
Nick Piggin949854d2011-01-07 17:49:37 +11001029 unsigned seq;
Nick Piggin58db63d2011-01-07 17:49:39 +11001030 int locked = 0;
Nick Piggin949854d2011-01-07 17:49:37 +11001031
Nick Piggin949854d2011-01-07 17:49:37 +11001032 seq = read_seqbegin(&rename_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11001033again:
1034 this_parent = parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 if (d_mountpoint(parent))
1037 goto positive;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001038 spin_lock(&this_parent->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039repeat:
1040 next = this_parent->d_subdirs.next;
1041resume:
1042 while (next != &this_parent->d_subdirs) {
1043 struct list_head *tmp = next;
Eric Dumazet5160ee62006-01-08 01:03:32 -08001044 struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 next = tmp->next;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001046
1047 spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 /* Have we found a mount point ? */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001049 if (d_mountpoint(dentry)) {
1050 spin_unlock(&dentry->d_lock);
1051 spin_unlock(&this_parent->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 goto positive;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001053 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 if (!list_empty(&dentry->d_subdirs)) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001055 spin_unlock(&this_parent->d_lock);
1056 spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 this_parent = dentry;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001058 spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 goto repeat;
1060 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001061 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062 }
1063 /*
1064 * All done at this level ... ascend and resume the search.
1065 */
1066 if (this_parent != parent) {
Nick Piggin949854d2011-01-07 17:49:37 +11001067 struct dentry *tmp;
1068 struct dentry *child;
1069
1070 tmp = this_parent->d_parent;
1071 rcu_read_lock();
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001072 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001073 child = this_parent;
1074 this_parent = tmp;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001075 spin_lock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001076 /* might go back up the wrong parent if we have had a rename
1077 * or deletion */
1078 if (this_parent != child->d_parent ||
Nick Piggin58db63d2011-01-07 17:49:39 +11001079 (!locked && read_seqretry(&rename_lock, seq))) {
Nick Piggin949854d2011-01-07 17:49:37 +11001080 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001081 rcu_read_unlock();
1082 goto rename_retry;
1083 }
1084 rcu_read_unlock();
1085 next = child->d_u.d_child.next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 goto resume;
1087 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001088 spin_unlock(&this_parent->d_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11001089 if (!locked && read_seqretry(&rename_lock, seq))
Nick Piggin949854d2011-01-07 17:49:37 +11001090 goto rename_retry;
Nick Piggin58db63d2011-01-07 17:49:39 +11001091 if (locked)
1092 write_sequnlock(&rename_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 return 0; /* No mount points found in tree */
1094positive:
Nick Piggin58db63d2011-01-07 17:49:39 +11001095 if (!locked && read_seqretry(&rename_lock, seq))
Nick Piggin949854d2011-01-07 17:49:37 +11001096 goto rename_retry;
Nick Piggin58db63d2011-01-07 17:49:39 +11001097 if (locked)
1098 write_sequnlock(&rename_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 return 1;
Nick Piggin58db63d2011-01-07 17:49:39 +11001100
1101rename_retry:
1102 locked = 1;
1103 write_seqlock(&rename_lock);
1104 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001106EXPORT_SYMBOL(have_submounts);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
1108/*
1109 * Search the dentry child list for the specified parent,
1110 * and move any unused dentries to the end of the unused
1111 * list for prune_dcache(). We descend to the next level
1112 * whenever the d_subdirs list is non-empty and continue
1113 * searching.
1114 *
1115 * It returns zero iff there are no unused children,
1116 * otherwise it returns the number of children moved to
1117 * the end of the unused list. This may not be the total
1118 * number of unused children, because select_parent can
1119 * drop the lock and return early due to latency
1120 * constraints.
1121 */
1122static int select_parent(struct dentry * parent)
1123{
Nick Piggin949854d2011-01-07 17:49:37 +11001124 struct dentry *this_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125 struct list_head *next;
Nick Piggin949854d2011-01-07 17:49:37 +11001126 unsigned seq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 int found = 0;
Nick Piggin58db63d2011-01-07 17:49:39 +11001128 int locked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129
Nick Piggin949854d2011-01-07 17:49:37 +11001130 seq = read_seqbegin(&rename_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11001131again:
1132 this_parent = parent;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001133 spin_lock(&this_parent->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134repeat:
1135 next = this_parent->d_subdirs.next;
1136resume:
1137 while (next != &this_parent->d_subdirs) {
1138 struct list_head *tmp = next;
Eric Dumazet5160ee62006-01-08 01:03:32 -08001139 struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 next = tmp->next;
1141
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001142 spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
Nick Piggin23044502011-01-07 17:49:31 +11001143
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 /*
1145 * move only zero ref count dentries to the end
1146 * of the unused list for prune_dcache
1147 */
Nick Pigginb7ab39f2011-01-07 17:49:32 +11001148 if (!dentry->d_count) {
Christoph Hellwiga4633352010-10-10 05:36:26 -04001149 dentry_lru_move_tail(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 found++;
Christoph Hellwiga4633352010-10-10 05:36:26 -04001151 } else {
1152 dentry_lru_del(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 }
1154
1155 /*
1156 * We can return to the caller if we have found some (this
1157 * ensures forward progress). We'll be coming back to find
1158 * the rest.
1159 */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001160 if (found && need_resched()) {
1161 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 goto out;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001163 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164
1165 /*
1166 * Descend a level if the d_subdirs list is non-empty.
1167 */
1168 if (!list_empty(&dentry->d_subdirs)) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001169 spin_unlock(&this_parent->d_lock);
1170 spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 this_parent = dentry;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001172 spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 goto repeat;
1174 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001175
1176 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 }
1178 /*
1179 * All done at this level ... ascend and resume the search.
1180 */
1181 if (this_parent != parent) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001182 struct dentry *tmp;
Nick Piggin949854d2011-01-07 17:49:37 +11001183 struct dentry *child;
1184
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001185 tmp = this_parent->d_parent;
Nick Piggin949854d2011-01-07 17:49:37 +11001186 rcu_read_lock();
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001187 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001188 child = this_parent;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001189 this_parent = tmp;
1190 spin_lock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001191 /* might go back up the wrong parent if we have had a rename
1192 * or deletion */
1193 if (this_parent != child->d_parent ||
Nick Piggin58db63d2011-01-07 17:49:39 +11001194 (!locked && read_seqretry(&rename_lock, seq))) {
Nick Piggin949854d2011-01-07 17:49:37 +11001195 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11001196 rcu_read_unlock();
1197 goto rename_retry;
1198 }
1199 rcu_read_unlock();
1200 next = child->d_u.d_child.next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 goto resume;
1202 }
1203out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001204 spin_unlock(&this_parent->d_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11001205 if (!locked && read_seqretry(&rename_lock, seq))
Nick Piggin949854d2011-01-07 17:49:37 +11001206 goto rename_retry;
Nick Piggin58db63d2011-01-07 17:49:39 +11001207 if (locked)
1208 write_sequnlock(&rename_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 return found;
Nick Piggin58db63d2011-01-07 17:49:39 +11001210
1211rename_retry:
1212 if (found)
1213 return found;
1214 locked = 1;
1215 write_seqlock(&rename_lock);
1216 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217}
1218
1219/**
1220 * shrink_dcache_parent - prune dcache
1221 * @parent: parent of entries to prune
1222 *
1223 * Prune the dcache to remove unused children of the parent dentry.
1224 */
1225
1226void shrink_dcache_parent(struct dentry * parent)
1227{
Kentaro Makitada3bbdd2008-07-23 21:27:13 -07001228 struct super_block *sb = parent->d_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 int found;
1230
1231 while ((found = select_parent(parent)) != 0)
Kentaro Makitada3bbdd2008-07-23 21:27:13 -07001232 __shrink_dcache_sb(sb, &found, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001234EXPORT_SYMBOL(shrink_dcache_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236/*
1237 * Scan `nr' dentries and return the number which remain.
1238 *
1239 * We need to avoid reentering the filesystem if the caller is performing a
1240 * GFP_NOFS allocation attempt. One example deadlock is:
1241 *
1242 * ext2_new_block->getblk->GFP->shrink_dcache_memory->prune_dcache->
1243 * prune_one_dentry->dput->dentry_iput->iput->inode->i_sb->s_op->put_inode->
1244 * ext2_discard_prealloc->ext2_free_blocks->lock_super->DEADLOCK.
1245 *
1246 * In this case we return -1 to tell the caller that we baled.
1247 */
Dave Chinner7f8275d2010-07-19 14:56:17 +10001248static int shrink_dcache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249{
1250 if (nr) {
1251 if (!(gfp_mask & __GFP_FS))
1252 return -1;
Kentaro Makitada3bbdd2008-07-23 21:27:13 -07001253 prune_dcache(nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 }
Christoph Hellwig312d3ca2010-10-10 05:36:23 -04001255
Nick Piggin86c87492011-01-07 17:49:18 +11001256 return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257}
1258
Rusty Russell8e1f9362007-07-17 04:03:17 -07001259static struct shrinker dcache_shrinker = {
1260 .shrink = shrink_dcache_memory,
1261 .seeks = DEFAULT_SEEKS,
1262};
1263
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264/**
1265 * d_alloc - allocate a dcache entry
1266 * @parent: parent of entry to allocate
1267 * @name: qstr of the name
1268 *
1269 * Allocates a dentry. It returns %NULL if there is insufficient memory
1270 * available. On a success the dentry is returned. The name passed in is
1271 * copied and the copy passed in may be reused after this call.
1272 */
1273
1274struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
1275{
1276 struct dentry *dentry;
1277 char *dname;
1278
Mel Gormane12ba742007-10-16 01:25:52 -07001279 dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 if (!dentry)
1281 return NULL;
1282
1283 if (name->len > DNAME_INLINE_LEN-1) {
1284 dname = kmalloc(name->len + 1, GFP_KERNEL);
1285 if (!dname) {
1286 kmem_cache_free(dentry_cache, dentry);
1287 return NULL;
1288 }
1289 } else {
1290 dname = dentry->d_iname;
1291 }
1292 dentry->d_name.name = dname;
1293
1294 dentry->d_name.len = name->len;
1295 dentry->d_name.hash = name->hash;
1296 memcpy(dname, name->name, name->len);
1297 dname[name->len] = 0;
1298
Nick Pigginb7ab39f2011-01-07 17:49:32 +11001299 dentry->d_count = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 dentry->d_flags = DCACHE_UNHASHED;
1301 spin_lock_init(&dentry->d_lock);
Nick Piggin31e6b012011-01-07 17:49:52 +11001302 seqcount_init(&dentry->d_seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 dentry->d_inode = NULL;
1304 dentry->d_parent = NULL;
1305 dentry->d_sb = NULL;
1306 dentry->d_op = NULL;
1307 dentry->d_fsdata = NULL;
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001308 INIT_HLIST_BL_NODE(&dentry->d_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 INIT_LIST_HEAD(&dentry->d_lru);
1310 INIT_LIST_HEAD(&dentry->d_subdirs);
1311 INIT_LIST_HEAD(&dentry->d_alias);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001312 INIT_LIST_HEAD(&dentry->d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313
1314 if (parent) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001315 spin_lock(&parent->d_lock);
Nick Piggin89ad4852011-01-07 17:49:41 +11001316 /*
1317 * don't need child lock because it is not subject
1318 * to concurrency here
1319 */
Nick Piggindc0474b2011-01-07 17:49:43 +11001320 __dget_dlock(parent);
1321 dentry->d_parent = parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 dentry->d_sb = parent->d_sb;
Eric Dumazet5160ee62006-01-08 01:03:32 -08001323 list_add(&dentry->d_u.d_child, &parent->d_subdirs);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001324 spin_unlock(&parent->d_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326
Nick Piggin3e880fb2011-01-07 17:49:19 +11001327 this_cpu_inc(nr_dentry);
Christoph Hellwig312d3ca2010-10-10 05:36:23 -04001328
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 return dentry;
1330}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001331EXPORT_SYMBOL(d_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332
1333struct dentry *d_alloc_name(struct dentry *parent, const char *name)
1334{
1335 struct qstr q;
1336
1337 q.name = name;
1338 q.len = strlen(name);
1339 q.hash = full_name_hash(q.name, q.len);
1340 return d_alloc(parent, &q);
1341}
H Hartley Sweetenef26ca92009-09-29 20:09:42 -04001342EXPORT_SYMBOL(d_alloc_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Nick Pigginfb045ad2011-01-07 17:49:55 +11001344void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
1345{
1346 BUG_ON(dentry->d_op);
1347 BUG_ON(dentry->d_flags & (DCACHE_OP_HASH |
1348 DCACHE_OP_COMPARE |
1349 DCACHE_OP_REVALIDATE |
1350 DCACHE_OP_DELETE ));
1351 dentry->d_op = op;
1352 if (!op)
1353 return;
1354 if (op->d_hash)
1355 dentry->d_flags |= DCACHE_OP_HASH;
1356 if (op->d_compare)
1357 dentry->d_flags |= DCACHE_OP_COMPARE;
1358 if (op->d_revalidate)
1359 dentry->d_flags |= DCACHE_OP_REVALIDATE;
1360 if (op->d_delete)
1361 dentry->d_flags |= DCACHE_OP_DELETE;
1362
1363}
1364EXPORT_SYMBOL(d_set_d_op);
1365
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001366static void __d_instantiate(struct dentry *dentry, struct inode *inode)
1367{
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001368 spin_lock(&dentry->d_lock);
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001369 if (inode)
1370 list_add(&dentry->d_alias, &inode->i_dentry);
1371 dentry->d_inode = inode;
Nick Piggin31e6b012011-01-07 17:49:52 +11001372 dentry_rcuwalk_barrier(dentry);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001373 spin_unlock(&dentry->d_lock);
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001374 fsnotify_d_instantiate(dentry, inode);
1375}
1376
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377/**
1378 * d_instantiate - fill in inode information for a dentry
1379 * @entry: dentry to complete
1380 * @inode: inode to attach to this dentry
1381 *
1382 * Fill in inode information in the entry.
1383 *
1384 * This turns negative dentries into productive full members
1385 * of society.
1386 *
1387 * NOTE! This assumes that the inode count has been incremented
1388 * (or otherwise set) by the caller to indicate that it is now
1389 * in use by the dcache.
1390 */
1391
1392void d_instantiate(struct dentry *entry, struct inode * inode)
1393{
Eric Sesterhenn28133c72006-03-26 18:25:39 +02001394 BUG_ON(!list_empty(&entry->d_alias));
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001395 spin_lock(&dcache_inode_lock);
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001396 __d_instantiate(entry, inode);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001397 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 security_d_instantiate(entry, inode);
1399}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001400EXPORT_SYMBOL(d_instantiate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
1402/**
1403 * d_instantiate_unique - instantiate a non-aliased dentry
1404 * @entry: dentry to instantiate
1405 * @inode: inode to attach to this dentry
1406 *
1407 * Fill in inode information in the entry. On success, it returns NULL.
1408 * If an unhashed alias of "entry" already exists, then we return the
Oleg Drokine866cfa2006-01-09 20:52:51 -08001409 * aliased dentry instead and drop one reference to inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 *
1411 * Note that in order to avoid conflicts with rename() etc, the caller
1412 * had better be holding the parent directory semaphore.
Oleg Drokine866cfa2006-01-09 20:52:51 -08001413 *
1414 * This also assumes that the inode count has been incremented
1415 * (or otherwise set) by the caller to indicate that it is now
1416 * in use by the dcache.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 */
David Howells770bfad2006-08-22 20:06:07 -04001418static struct dentry *__d_instantiate_unique(struct dentry *entry,
1419 struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420{
1421 struct dentry *alias;
1422 int len = entry->d_name.len;
1423 const char *name = entry->d_name.name;
1424 unsigned int hash = entry->d_name.hash;
1425
David Howells770bfad2006-08-22 20:06:07 -04001426 if (!inode) {
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001427 __d_instantiate(entry, NULL);
David Howells770bfad2006-08-22 20:06:07 -04001428 return NULL;
1429 }
1430
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
1432 struct qstr *qstr = &alias->d_name;
1433
Nick Piggin9abca362011-01-07 17:49:36 +11001434 /*
1435 * Don't need alias->d_lock here, because aliases with
1436 * d_parent == entry->d_parent are not subject to name or
1437 * parent changes, because the parent inode i_mutex is held.
1438 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 if (qstr->hash != hash)
1440 continue;
1441 if (alias->d_parent != entry->d_parent)
1442 continue;
1443 if (qstr->len != len)
1444 continue;
1445 if (memcmp(qstr->name, name, len))
1446 continue;
Nick Piggindc0474b2011-01-07 17:49:43 +11001447 __dget(alias);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001448 return alias;
1449 }
David Howells770bfad2006-08-22 20:06:07 -04001450
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001451 __d_instantiate(entry, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 return NULL;
1453}
David Howells770bfad2006-08-22 20:06:07 -04001454
1455struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
1456{
1457 struct dentry *result;
1458
1459 BUG_ON(!list_empty(&entry->d_alias));
1460
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001461 spin_lock(&dcache_inode_lock);
David Howells770bfad2006-08-22 20:06:07 -04001462 result = __d_instantiate_unique(entry, inode);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001463 spin_unlock(&dcache_inode_lock);
David Howells770bfad2006-08-22 20:06:07 -04001464
1465 if (!result) {
1466 security_d_instantiate(entry, inode);
1467 return NULL;
1468 }
1469
1470 BUG_ON(!d_unhashed(result));
1471 iput(inode);
1472 return result;
1473}
1474
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475EXPORT_SYMBOL(d_instantiate_unique);
1476
1477/**
1478 * d_alloc_root - allocate root dentry
1479 * @root_inode: inode to allocate the root for
1480 *
1481 * Allocate a root ("/") dentry for the inode given. The inode is
1482 * instantiated and returned. %NULL is returned if there is insufficient
1483 * memory or the inode passed is %NULL.
1484 */
1485
1486struct dentry * d_alloc_root(struct inode * root_inode)
1487{
1488 struct dentry *res = NULL;
1489
1490 if (root_inode) {
1491 static const struct qstr name = { .name = "/", .len = 1 };
1492
1493 res = d_alloc(NULL, &name);
1494 if (res) {
1495 res->d_sb = root_inode->i_sb;
1496 res->d_parent = res;
1497 d_instantiate(res, root_inode);
1498 }
1499 }
1500 return res;
1501}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001502EXPORT_SYMBOL(d_alloc_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001503
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504/**
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001505 * d_obtain_alias - find or allocate a dentry for a given inode
1506 * @inode: inode to allocate the dentry for
1507 *
1508 * Obtain a dentry for an inode resulting from NFS filehandle conversion or
1509 * similar open by handle operations. The returned dentry may be anonymous,
1510 * or may have a full name (if the inode was already in the cache).
1511 *
1512 * When called on a directory inode, we must ensure that the inode only ever
1513 * has one dentry. If a dentry is found, that is returned instead of
1514 * allocating a new one.
1515 *
1516 * On successful return, the reference to the inode has been transferred
Christoph Hellwig44003722008-08-11 15:49:04 +02001517 * to the dentry. In case of an error the reference on the inode is released.
1518 * To make it easier to use in export operations a %NULL or IS_ERR inode may
1519 * be passed in and will be the error will be propagate to the return value,
1520 * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001521 */
1522struct dentry *d_obtain_alias(struct inode *inode)
1523{
Christoph Hellwig9308a612008-08-11 15:49:12 +02001524 static const struct qstr anonstring = { .name = "" };
1525 struct dentry *tmp;
1526 struct dentry *res;
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001527
1528 if (!inode)
Christoph Hellwig44003722008-08-11 15:49:04 +02001529 return ERR_PTR(-ESTALE);
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001530 if (IS_ERR(inode))
1531 return ERR_CAST(inode);
1532
Christoph Hellwig9308a612008-08-11 15:49:12 +02001533 res = d_find_alias(inode);
1534 if (res)
1535 goto out_iput;
1536
1537 tmp = d_alloc(NULL, &anonstring);
1538 if (!tmp) {
1539 res = ERR_PTR(-ENOMEM);
1540 goto out_iput;
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001541 }
Christoph Hellwig9308a612008-08-11 15:49:12 +02001542 tmp->d_parent = tmp; /* make sure dput doesn't croak */
1543
Nick Pigginb5c84bf2011-01-07 17:49:38 +11001544
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001545 spin_lock(&dcache_inode_lock);
Christoph Hellwig9308a612008-08-11 15:49:12 +02001546 res = __d_find_alias(inode, 0);
1547 if (res) {
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001548 spin_unlock(&dcache_inode_lock);
Christoph Hellwig9308a612008-08-11 15:49:12 +02001549 dput(tmp);
1550 goto out_iput;
1551 }
1552
1553 /* attach a disconnected dentry */
1554 spin_lock(&tmp->d_lock);
1555 tmp->d_sb = inode->i_sb;
1556 tmp->d_inode = inode;
1557 tmp->d_flags |= DCACHE_DISCONNECTED;
Christoph Hellwig9308a612008-08-11 15:49:12 +02001558 list_add(&tmp->d_alias, &inode->i_dentry);
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001559 bit_spin_lock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
1560 tmp->d_flags &= ~DCACHE_UNHASHED;
1561 hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
1562 __bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
Christoph Hellwig9308a612008-08-11 15:49:12 +02001563 spin_unlock(&tmp->d_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001564 spin_unlock(&dcache_inode_lock);
Christoph Hellwig9308a612008-08-11 15:49:12 +02001565
Christoph Hellwig9308a612008-08-11 15:49:12 +02001566 return tmp;
1567
1568 out_iput:
1569 iput(inode);
1570 return res;
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +02001571}
Benny Halevyadc48722009-02-27 14:02:59 -08001572EXPORT_SYMBOL(d_obtain_alias);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573
1574/**
1575 * d_splice_alias - splice a disconnected dentry into the tree if one exists
1576 * @inode: the inode which may have a disconnected dentry
1577 * @dentry: a negative dentry which we want to point to the inode.
1578 *
1579 * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and
1580 * DCACHE_DISCONNECTED), then d_move that in place of the given dentry
1581 * and return it, else simply d_add the inode to the dentry and return NULL.
1582 *
1583 * This is needed in the lookup routine of any filesystem that is exportable
1584 * (via knfsd) so that we can build dcache paths to directories effectively.
1585 *
1586 * If a dentry was found and moved, then it is returned. Otherwise NULL
1587 * is returned. This matches the expected return value of ->lookup.
1588 *
1589 */
1590struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
1591{
1592 struct dentry *new = NULL;
1593
NeilBrown21c0d8f2006-10-04 02:16:16 -07001594 if (inode && S_ISDIR(inode->i_mode)) {
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001595 spin_lock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596 new = __d_find_alias(inode, 1);
1597 if (new) {
1598 BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001599 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 security_d_instantiate(new, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601 d_move(new, dentry);
1602 iput(inode);
1603 } else {
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001604 /* already got dcache_inode_lock, so d_add() by hand */
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001605 __d_instantiate(dentry, inode);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001606 spin_unlock(&dcache_inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 security_d_instantiate(dentry, inode);
1608 d_rehash(dentry);
1609 }
1610 } else
1611 d_add(dentry, inode);
1612 return new;
1613}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001614EXPORT_SYMBOL(d_splice_alias);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615
Barry Naujok94035402008-05-21 16:50:46 +10001616/**
1617 * d_add_ci - lookup or allocate new dentry with case-exact name
1618 * @inode: the inode case-insensitive lookup has found
1619 * @dentry: the negative dentry that was passed to the parent's lookup func
1620 * @name: the case-exact name to be associated with the returned dentry
1621 *
1622 * This is to avoid filling the dcache with case-insensitive names to the
1623 * same inode, only the actual correct case is stored in the dcache for
1624 * case-insensitive filesystems.
1625 *
1626 * For a case-insensitive lookup match and if the the case-exact dentry
1627 * already exists in in the dcache, use it and return it.
1628 *
1629 * If no entry exists with the exact case name, allocate new dentry with
1630 * the exact case, and return the spliced entry.
1631 */
Christoph Hellwige45b5902008-08-07 23:49:07 +02001632struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
Barry Naujok94035402008-05-21 16:50:46 +10001633 struct qstr *name)
1634{
1635 int error;
1636 struct dentry *found;
1637 struct dentry *new;
1638
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001639 /*
1640 * First check if a dentry matching the name already exists,
1641 * if not go ahead and create it now.
1642 */
Barry Naujok94035402008-05-21 16:50:46 +10001643 found = d_hash_and_lookup(dentry->d_parent, name);
Barry Naujok94035402008-05-21 16:50:46 +10001644 if (!found) {
1645 new = d_alloc(dentry->d_parent, name);
1646 if (!new) {
1647 error = -ENOMEM;
1648 goto err_out;
1649 }
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001650
Barry Naujok94035402008-05-21 16:50:46 +10001651 found = d_splice_alias(inode, new);
1652 if (found) {
1653 dput(new);
1654 return found;
1655 }
1656 return new;
1657 }
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001658
1659 /*
1660 * If a matching dentry exists, and it's not negative use it.
1661 *
1662 * Decrement the reference count to balance the iget() done
1663 * earlier on.
1664 */
Barry Naujok94035402008-05-21 16:50:46 +10001665 if (found->d_inode) {
1666 if (unlikely(found->d_inode != inode)) {
1667 /* This can't happen because bad inodes are unhashed. */
1668 BUG_ON(!is_bad_inode(inode));
1669 BUG_ON(!is_bad_inode(found->d_inode));
1670 }
Barry Naujok94035402008-05-21 16:50:46 +10001671 iput(inode);
1672 return found;
1673 }
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001674
Barry Naujok94035402008-05-21 16:50:46 +10001675 /*
1676 * Negative dentry: instantiate it unless the inode is a directory and
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001677 * already has a dentry.
Barry Naujok94035402008-05-21 16:50:46 +10001678 */
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001679 spin_lock(&dcache_inode_lock);
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001680 if (!S_ISDIR(inode->i_mode) || list_empty(&inode->i_dentry)) {
OGAWA Hirofumi360da902008-10-16 07:50:28 +09001681 __d_instantiate(found, inode);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001682 spin_unlock(&dcache_inode_lock);
Barry Naujok94035402008-05-21 16:50:46 +10001683 security_d_instantiate(found, inode);
1684 return found;
1685 }
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001686
Barry Naujok94035402008-05-21 16:50:46 +10001687 /*
Christoph Hellwigb6520c82009-01-05 19:10:37 +01001688 * In case a directory already has a (disconnected) entry grab a
1689 * reference to it, move it in place and use it.
Barry Naujok94035402008-05-21 16:50:46 +10001690 */
1691 new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
Nick Piggindc0474b2011-01-07 17:49:43 +11001692 __dget(new);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11001693 spin_unlock(&dcache_inode_lock);
Barry Naujok94035402008-05-21 16:50:46 +10001694 security_d_instantiate(found, inode);
Barry Naujok94035402008-05-21 16:50:46 +10001695 d_move(new, found);
Barry Naujok94035402008-05-21 16:50:46 +10001696 iput(inode);
Barry Naujok94035402008-05-21 16:50:46 +10001697 dput(found);
Barry Naujok94035402008-05-21 16:50:46 +10001698 return new;
1699
1700err_out:
1701 iput(inode);
1702 return ERR_PTR(error);
1703}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001704EXPORT_SYMBOL(d_add_ci);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705
1706/**
Nick Piggin31e6b012011-01-07 17:49:52 +11001707 * __d_lookup_rcu - search for a dentry (racy, store-free)
1708 * @parent: parent dentry
1709 * @name: qstr of name we wish to find
1710 * @seq: returns d_seq value at the point where the dentry was found
1711 * @inode: returns dentry->d_inode when the inode was found valid.
1712 * Returns: dentry, or NULL
1713 *
1714 * __d_lookup_rcu is the dcache lookup function for rcu-walk name
1715 * resolution (store-free path walking) design described in
1716 * Documentation/filesystems/path-lookup.txt.
1717 *
1718 * This is not to be used outside core vfs.
1719 *
1720 * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock
1721 * held, and rcu_read_lock held. The returned dentry must not be stored into
1722 * without taking d_lock and checking d_seq sequence count against @seq
1723 * returned here.
1724 *
1725 * A refcount may be taken on the found dentry with the __d_rcu_to_refcount
1726 * function.
1727 *
1728 * Alternatively, __d_lookup_rcu may be called again to look up the child of
1729 * the returned dentry, so long as its parent's seqlock is checked after the
1730 * child is looked up. Thus, an interlocking stepping of sequence lock checks
1731 * is formed, giving integrity down the path walk.
1732 */
1733struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
1734 unsigned *seq, struct inode **inode)
1735{
1736 unsigned int len = name->len;
1737 unsigned int hash = name->hash;
1738 const unsigned char *str = name->name;
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001739 struct dcache_hash_bucket *b = d_hash(parent, hash);
1740 struct hlist_bl_node *node;
Nick Piggin31e6b012011-01-07 17:49:52 +11001741 struct dentry *dentry;
1742
1743 /*
1744 * Note: There is significant duplication with __d_lookup_rcu which is
1745 * required to prevent single threaded performance regressions
1746 * especially on architectures where smp_rmb (in seqcounts) are costly.
1747 * Keep the two functions in sync.
1748 */
1749
1750 /*
1751 * The hash list is protected using RCU.
1752 *
1753 * Carefully use d_seq when comparing a candidate dentry, to avoid
1754 * races with d_move().
1755 *
1756 * It is possible that concurrent renames can mess up our list
1757 * walk here and result in missing our dentry, resulting in the
1758 * false-negative result. d_lookup() protects against concurrent
1759 * renames using rename_lock seqlock.
1760 *
1761 * See Documentation/vfs/dcache-locking.txt for more details.
1762 */
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001763 hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
Nick Piggin31e6b012011-01-07 17:49:52 +11001764 struct inode *i;
1765 const char *tname;
1766 int tlen;
1767
1768 if (dentry->d_name.hash != hash)
1769 continue;
1770
1771seqretry:
1772 *seq = read_seqcount_begin(&dentry->d_seq);
1773 if (dentry->d_parent != parent)
1774 continue;
1775 if (d_unhashed(dentry))
1776 continue;
1777 tlen = dentry->d_name.len;
1778 tname = dentry->d_name.name;
1779 i = dentry->d_inode;
1780 /*
1781 * This seqcount check is required to ensure name and
1782 * len are loaded atomically, so as not to walk off the
1783 * edge of memory when walking. If we could load this
1784 * atomically some other way, we could drop this check.
1785 */
1786 if (read_seqcount_retry(&dentry->d_seq, *seq))
1787 goto seqretry;
Nick Pigginfb045ad2011-01-07 17:49:55 +11001788 if (parent->d_flags & DCACHE_OP_COMPARE) {
Nick Piggin31e6b012011-01-07 17:49:52 +11001789 if (parent->d_op->d_compare(parent, *inode,
1790 dentry, i,
1791 tlen, tname, name))
1792 continue;
1793 } else {
1794 if (tlen != len)
1795 continue;
1796 if (memcmp(tname, str, tlen))
1797 continue;
1798 }
1799 /*
1800 * No extra seqcount check is required after the name
1801 * compare. The caller must perform a seqcount check in
1802 * order to do anything useful with the returned dentry
1803 * anyway.
1804 */
1805 *inode = i;
1806 return dentry;
1807 }
1808 return NULL;
1809}
1810
1811/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812 * d_lookup - search for a dentry
1813 * @parent: parent dentry
1814 * @name: qstr of name we wish to find
Nick Pigginb04f7842010-08-18 04:37:34 +10001815 * Returns: dentry, or NULL
Linus Torvalds1da177e2005-04-16 15:20:36 -07001816 *
Nick Pigginb04f7842010-08-18 04:37:34 +10001817 * d_lookup searches the children of the parent dentry for the name in
1818 * question. If the dentry is found its reference count is incremented and the
1819 * dentry is returned. The caller must use dput to free the entry when it has
1820 * finished using it. %NULL is returned if the dentry does not exist.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 */
Nick Piggin31e6b012011-01-07 17:49:52 +11001822struct dentry *d_lookup(struct dentry *parent, struct qstr *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823{
Nick Piggin31e6b012011-01-07 17:49:52 +11001824 struct dentry *dentry;
Nick Piggin949854d2011-01-07 17:49:37 +11001825 unsigned seq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826
1827 do {
1828 seq = read_seqbegin(&rename_lock);
1829 dentry = __d_lookup(parent, name);
1830 if (dentry)
1831 break;
1832 } while (read_seqretry(&rename_lock, seq));
1833 return dentry;
1834}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001835EXPORT_SYMBOL(d_lookup);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836
Nick Piggin31e6b012011-01-07 17:49:52 +11001837/**
Nick Pigginb04f7842010-08-18 04:37:34 +10001838 * __d_lookup - search for a dentry (racy)
1839 * @parent: parent dentry
1840 * @name: qstr of name we wish to find
1841 * Returns: dentry, or NULL
1842 *
1843 * __d_lookup is like d_lookup, however it may (rarely) return a
1844 * false-negative result due to unrelated rename activity.
1845 *
1846 * __d_lookup is slightly faster by avoiding rename_lock read seqlock,
1847 * however it must be used carefully, eg. with a following d_lookup in
1848 * the case of failure.
1849 *
1850 * __d_lookup callers must be commented.
1851 */
Nick Piggin31e6b012011-01-07 17:49:52 +11001852struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853{
1854 unsigned int len = name->len;
1855 unsigned int hash = name->hash;
1856 const unsigned char *str = name->name;
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001857 struct dcache_hash_bucket *b = d_hash(parent, hash);
1858 struct hlist_bl_node *node;
Nick Piggin31e6b012011-01-07 17:49:52 +11001859 struct dentry *found = NULL;
Paul E. McKenney665a7582005-11-07 00:59:17 -08001860 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861
Nick Pigginb04f7842010-08-18 04:37:34 +10001862 /*
Nick Piggin31e6b012011-01-07 17:49:52 +11001863 * Note: There is significant duplication with __d_lookup_rcu which is
1864 * required to prevent single threaded performance regressions
1865 * especially on architectures where smp_rmb (in seqcounts) are costly.
1866 * Keep the two functions in sync.
1867 */
1868
1869 /*
Nick Pigginb04f7842010-08-18 04:37:34 +10001870 * The hash list is protected using RCU.
1871 *
1872 * Take d_lock when comparing a candidate dentry, to avoid races
1873 * with d_move().
1874 *
1875 * It is possible that concurrent renames can mess up our list
1876 * walk here and result in missing our dentry, resulting in the
1877 * false-negative result. d_lookup() protects against concurrent
1878 * renames using rename_lock seqlock.
1879 *
1880 * See Documentation/vfs/dcache-locking.txt for more details.
1881 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 rcu_read_lock();
1883
Nick Pigginceb5bdc2011-01-07 17:50:05 +11001884 hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
Nick Piggin31e6b012011-01-07 17:49:52 +11001885 const char *tname;
1886 int tlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 if (dentry->d_name.hash != hash)
1889 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890
1891 spin_lock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892 if (dentry->d_parent != parent)
1893 goto next;
Linus Torvaldsd0185c02008-09-29 07:42:57 -07001894 if (d_unhashed(dentry))
1895 goto next;
1896
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897 /*
1898 * It is safe to compare names since d_move() cannot
1899 * change the qstr (protected by d_lock).
1900 */
Nick Piggin31e6b012011-01-07 17:49:52 +11001901 tlen = dentry->d_name.len;
1902 tname = dentry->d_name.name;
Nick Pigginfb045ad2011-01-07 17:49:55 +11001903 if (parent->d_flags & DCACHE_OP_COMPARE) {
Nick Piggin621e1552011-01-07 17:49:27 +11001904 if (parent->d_op->d_compare(parent, parent->d_inode,
1905 dentry, dentry->d_inode,
Nick Piggin31e6b012011-01-07 17:49:52 +11001906 tlen, tname, name))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907 goto next;
1908 } else {
Nick Piggin31e6b012011-01-07 17:49:52 +11001909 if (tlen != len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 goto next;
Nick Piggin31e6b012011-01-07 17:49:52 +11001911 if (memcmp(tname, str, tlen))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912 goto next;
1913 }
1914
Nick Pigginb7ab39f2011-01-07 17:49:32 +11001915 dentry->d_count++;
Linus Torvaldsd0185c02008-09-29 07:42:57 -07001916 found = dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 spin_unlock(&dentry->d_lock);
1918 break;
1919next:
1920 spin_unlock(&dentry->d_lock);
1921 }
1922 rcu_read_unlock();
1923
1924 return found;
1925}
1926
1927/**
Eric W. Biederman3e7e2412006-03-31 02:31:43 -08001928 * d_hash_and_lookup - hash the qstr then search for a dentry
1929 * @dir: Directory to search in
1930 * @name: qstr of name we wish to find
1931 *
1932 * On hash failure or on lookup failure NULL is returned.
1933 */
1934struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
1935{
1936 struct dentry *dentry = NULL;
1937
1938 /*
1939 * Check for a fs-specific hash function. Note that we must
1940 * calculate the standard hash first, as the d_op->d_hash()
1941 * routine may choose to leave the hash value unchanged.
1942 */
1943 name->hash = full_name_hash(name->name, name->len);
Nick Pigginfb045ad2011-01-07 17:49:55 +11001944 if (dir->d_flags & DCACHE_OP_HASH) {
Nick Pigginb1e6a012011-01-07 17:49:28 +11001945 if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0)
Eric W. Biederman3e7e2412006-03-31 02:31:43 -08001946 goto out;
1947 }
1948 dentry = d_lookup(dir, name);
1949out:
1950 return dentry;
1951}
1952
1953/**
Nick Piggin786a5e12011-01-07 17:49:16 +11001954 * d_validate - verify dentry provided from insecure source (deprecated)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955 * @dentry: The dentry alleged to be valid child of @dparent
1956 * @dparent: The parent dentry (known to be valid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957 *
1958 * An insecure source has sent us a dentry, here we verify it and dget() it.
1959 * This is used by ncpfs in its readdir implementation.
1960 * Zero is returned in the dentry is invalid.
Nick Piggin786a5e12011-01-07 17:49:16 +11001961 *
1962 * This function is slow for big directories, and deprecated, do not use it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963 */
Nick Piggind3a23e12011-01-05 20:01:21 +11001964int d_validate(struct dentry *dentry, struct dentry *dparent)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001965{
Nick Piggin786a5e12011-01-07 17:49:16 +11001966 struct dentry *child;
Nick Piggind3a23e12011-01-05 20:01:21 +11001967
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001968 spin_lock(&dparent->d_lock);
Nick Piggin786a5e12011-01-07 17:49:16 +11001969 list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) {
1970 if (dentry == child) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001971 spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
Nick Piggindc0474b2011-01-07 17:49:43 +11001972 __dget_dlock(dentry);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001973 spin_unlock(&dentry->d_lock);
1974 spin_unlock(&dparent->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 return 1;
1976 }
1977 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11001978 spin_unlock(&dparent->d_lock);
Nick Piggin786a5e12011-01-07 17:49:16 +11001979
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 return 0;
1981}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07001982EXPORT_SYMBOL(d_validate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983
1984/*
1985 * When a file is deleted, we have two options:
1986 * - turn this dentry into a negative dentry
1987 * - unhash this dentry and free it.
1988 *
1989 * Usually, we want to just turn this into
1990 * a negative dentry, but if anybody else is
1991 * currently using the dentry or the inode
1992 * we can't do that and we fall back on removing
1993 * it from the hash queues and waiting for
1994 * it to be deleted later when it has no users
1995 */
1996
1997/**
1998 * d_delete - delete a dentry
1999 * @dentry: The dentry to delete
2000 *
2001 * Turn the dentry into a negative dentry if possible, otherwise
2002 * remove it from the hash queues so it can be deleted later
2003 */
2004
2005void d_delete(struct dentry * dentry)
2006{
John McCutchan7a91bf72005-08-08 13:52:16 -04002007 int isdir = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 /*
2009 * Are we the only user?
2010 */
Nick Piggin357f8e62011-01-07 17:49:42 +11002011again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012 spin_lock(&dentry->d_lock);
John McCutchan7a91bf72005-08-08 13:52:16 -04002013 isdir = S_ISDIR(dentry->d_inode->i_mode);
Nick Pigginb7ab39f2011-01-07 17:49:32 +11002014 if (dentry->d_count == 1) {
Nick Piggin357f8e62011-01-07 17:49:42 +11002015 if (!spin_trylock(&dcache_inode_lock)) {
2016 spin_unlock(&dentry->d_lock);
2017 cpu_relax();
2018 goto again;
2019 }
Al Viro13e3c5e2010-05-21 16:11:04 -04002020 dentry->d_flags &= ~DCACHE_CANT_MOUNT;
Nick Piggin31e6b012011-01-07 17:49:52 +11002021 dentry_unlink_inode(dentry);
John McCutchan7a91bf72005-08-08 13:52:16 -04002022 fsnotify_nameremove(dentry, isdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 return;
2024 }
2025
2026 if (!d_unhashed(dentry))
2027 __d_drop(dentry);
2028
2029 spin_unlock(&dentry->d_lock);
John McCutchan7a91bf72005-08-08 13:52:16 -04002030
2031 fsnotify_nameremove(dentry, isdir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002033EXPORT_SYMBOL(d_delete);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002035static void __d_rehash(struct dentry * entry, struct dcache_hash_bucket *b)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036{
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002037 BUG_ON(!d_unhashed(entry));
2038 spin_lock_bucket(b);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039 entry->d_flags &= ~DCACHE_UNHASHED;
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002040 hlist_bl_add_head_rcu(&entry->d_hash, &b->head);
2041 spin_unlock_bucket(b);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042}
2043
David Howells770bfad2006-08-22 20:06:07 -04002044static void _d_rehash(struct dentry * entry)
2045{
2046 __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash));
2047}
2048
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049/**
2050 * d_rehash - add an entry back to the hash
2051 * @entry: dentry to add to the hash
2052 *
2053 * Adds a dentry to the hash according to its name.
2054 */
2055
2056void d_rehash(struct dentry * entry)
2057{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002058 spin_lock(&entry->d_lock);
David Howells770bfad2006-08-22 20:06:07 -04002059 _d_rehash(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060 spin_unlock(&entry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002062EXPORT_SYMBOL(d_rehash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002063
Nick Pigginfb2d5b82011-01-07 17:49:26 +11002064/**
2065 * dentry_update_name_case - update case insensitive dentry with a new name
2066 * @dentry: dentry to be updated
2067 * @name: new name
2068 *
2069 * Update a case insensitive dentry with new case of name.
2070 *
2071 * dentry must have been returned by d_lookup with name @name. Old and new
2072 * name lengths must match (ie. no d_compare which allows mismatched name
2073 * lengths).
2074 *
2075 * Parent inode i_mutex must be held over d_lookup and into this call (to
2076 * keep renames and concurrent inserts, and readdir(2) away).
2077 */
2078void dentry_update_name_case(struct dentry *dentry, struct qstr *name)
2079{
2080 BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
2081 BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */
2082
Nick Pigginfb2d5b82011-01-07 17:49:26 +11002083 spin_lock(&dentry->d_lock);
Nick Piggin31e6b012011-01-07 17:49:52 +11002084 write_seqcount_begin(&dentry->d_seq);
Nick Pigginfb2d5b82011-01-07 17:49:26 +11002085 memcpy((unsigned char *)dentry->d_name.name, name->name, name->len);
Nick Piggin31e6b012011-01-07 17:49:52 +11002086 write_seqcount_end(&dentry->d_seq);
Nick Pigginfb2d5b82011-01-07 17:49:26 +11002087 spin_unlock(&dentry->d_lock);
Nick Pigginfb2d5b82011-01-07 17:49:26 +11002088}
2089EXPORT_SYMBOL(dentry_update_name_case);
2090
Linus Torvalds1da177e2005-04-16 15:20:36 -07002091static void switch_names(struct dentry *dentry, struct dentry *target)
2092{
2093 if (dname_external(target)) {
2094 if (dname_external(dentry)) {
2095 /*
2096 * Both external: swap the pointers
2097 */
Wu Fengguang9a8d5bb2009-01-07 18:09:14 -08002098 swap(target->d_name.name, dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099 } else {
2100 /*
2101 * dentry:internal, target:external. Steal target's
2102 * storage and make target internal.
2103 */
J. Bruce Fields321bcf92007-10-21 16:41:38 -07002104 memcpy(target->d_iname, dentry->d_name.name,
2105 dentry->d_name.len + 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002106 dentry->d_name.name = target->d_name.name;
2107 target->d_name.name = target->d_iname;
2108 }
2109 } else {
2110 if (dname_external(dentry)) {
2111 /*
2112 * dentry:external, target:internal. Give dentry's
2113 * storage to target and make dentry internal
2114 */
2115 memcpy(dentry->d_iname, target->d_name.name,
2116 target->d_name.len + 1);
2117 target->d_name.name = dentry->d_name.name;
2118 dentry->d_name.name = dentry->d_iname;
2119 } else {
2120 /*
2121 * Both are internal. Just copy target to dentry
2122 */
2123 memcpy(dentry->d_iname, target->d_name.name,
2124 target->d_name.len + 1);
Al Virodc711ca2008-11-03 15:03:50 -05002125 dentry->d_name.len = target->d_name.len;
2126 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127 }
2128 }
Wu Fengguang9a8d5bb2009-01-07 18:09:14 -08002129 swap(dentry->d_name.len, target->d_name.len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130}
2131
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002132static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
2133{
2134 /*
2135 * XXXX: do we really need to take target->d_lock?
2136 */
2137 if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent)
2138 spin_lock(&target->d_parent->d_lock);
2139 else {
2140 if (d_ancestor(dentry->d_parent, target->d_parent)) {
2141 spin_lock(&dentry->d_parent->d_lock);
2142 spin_lock_nested(&target->d_parent->d_lock,
2143 DENTRY_D_LOCK_NESTED);
2144 } else {
2145 spin_lock(&target->d_parent->d_lock);
2146 spin_lock_nested(&dentry->d_parent->d_lock,
2147 DENTRY_D_LOCK_NESTED);
2148 }
2149 }
2150 if (target < dentry) {
2151 spin_lock_nested(&target->d_lock, 2);
2152 spin_lock_nested(&dentry->d_lock, 3);
2153 } else {
2154 spin_lock_nested(&dentry->d_lock, 2);
2155 spin_lock_nested(&target->d_lock, 3);
2156 }
2157}
2158
2159static void dentry_unlock_parents_for_move(struct dentry *dentry,
2160 struct dentry *target)
2161{
2162 if (target->d_parent != dentry->d_parent)
2163 spin_unlock(&dentry->d_parent->d_lock);
2164 if (target->d_parent != target)
2165 spin_unlock(&target->d_parent->d_lock);
2166}
2167
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168/*
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002169 * When switching names, the actual string doesn't strictly have to
2170 * be preserved in the target - because we're dropping the target
2171 * anyway. As such, we can just do a simple memcpy() to copy over
2172 * the new name before we switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173 *
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002174 * Note that we have to be a lot more careful about getting the hash
2175 * switched - we have to switch the hash value properly even if it
2176 * then no longer matches the actual (corrupted) string of the target.
2177 * The hash value has to match the hash queue that the dentry is on..
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178 */
Trond Myklebust9eaef272006-10-21 10:24:20 -07002179/*
Nick Pigginb5c84bf2011-01-07 17:49:38 +11002180 * d_move - move a dentry
Linus Torvalds1da177e2005-04-16 15:20:36 -07002181 * @dentry: entry to move
2182 * @target: new dentry
2183 *
2184 * Update the dcache to reflect the move of a file name. Negative
2185 * dcache entries should not be moved in this way.
2186 */
Nick Pigginb5c84bf2011-01-07 17:49:38 +11002187void d_move(struct dentry * dentry, struct dentry * target)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002188{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002189 if (!dentry->d_inode)
2190 printk(KERN_WARNING "VFS: moving negative dcache entry\n");
2191
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002192 BUG_ON(d_ancestor(dentry, target));
2193 BUG_ON(d_ancestor(target, dentry));
2194
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195 write_seqlock(&rename_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002196
2197 dentry_lock_for_move(dentry, target);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198
Nick Piggin31e6b012011-01-07 17:49:52 +11002199 write_seqcount_begin(&dentry->d_seq);
2200 write_seqcount_begin(&target->d_seq);
2201
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002202 /* __d_drop does write_seqcount_barrier, but they're OK to nest. */
2203
2204 /*
2205 * Move the dentry to the target hash queue. Don't bother checking
2206 * for the same hash queue because of how unlikely it is.
2207 */
2208 __d_drop(dentry);
Nick Piggin789680d2011-01-07 17:49:30 +11002209 __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210
2211 /* Unhash the target: dput() will then get rid of it */
2212 __d_drop(target);
2213
Eric Dumazet5160ee62006-01-08 01:03:32 -08002214 list_del(&dentry->d_u.d_child);
2215 list_del(&target->d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216
2217 /* Switch the names.. */
2218 switch_names(dentry, target);
Wu Fengguang9a8d5bb2009-01-07 18:09:14 -08002219 swap(dentry->d_name.hash, target->d_name.hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220
2221 /* ... and switch the parents */
2222 if (IS_ROOT(dentry)) {
2223 dentry->d_parent = target->d_parent;
2224 target->d_parent = target;
Eric Dumazet5160ee62006-01-08 01:03:32 -08002225 INIT_LIST_HEAD(&target->d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 } else {
Wu Fengguang9a8d5bb2009-01-07 18:09:14 -08002227 swap(dentry->d_parent, target->d_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002228
2229 /* And add them back to the (new) parent lists */
Eric Dumazet5160ee62006-01-08 01:03:32 -08002230 list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 }
2232
Eric Dumazet5160ee62006-01-08 01:03:32 -08002233 list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002234
Nick Piggin31e6b012011-01-07 17:49:52 +11002235 write_seqcount_end(&target->d_seq);
2236 write_seqcount_end(&dentry->d_seq);
2237
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002238 dentry_unlock_parents_for_move(dentry, target);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002239 spin_unlock(&target->d_lock);
Nick Pigginc32ccd82006-03-25 03:07:09 -08002240 fsnotify_d_move(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002241 spin_unlock(&dentry->d_lock);
2242 write_sequnlock(&rename_lock);
Trond Myklebust9eaef272006-10-21 10:24:20 -07002243}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002244EXPORT_SYMBOL(d_move);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002246/**
2247 * d_ancestor - search for an ancestor
2248 * @p1: ancestor dentry
2249 * @p2: child dentry
2250 *
2251 * Returns the ancestor dentry of p2 which is a child of p1, if p1 is
2252 * an ancestor of p2, else NULL.
Trond Myklebust9eaef272006-10-21 10:24:20 -07002253 */
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002254struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
Trond Myklebust9eaef272006-10-21 10:24:20 -07002255{
2256 struct dentry *p;
2257
OGAWA Hirofumi871c0062008-10-16 07:50:27 +09002258 for (p = p2; !IS_ROOT(p); p = p->d_parent) {
Trond Myklebust9eaef272006-10-21 10:24:20 -07002259 if (p->d_parent == p1)
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002260 return p;
Trond Myklebust9eaef272006-10-21 10:24:20 -07002261 }
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002262 return NULL;
Trond Myklebust9eaef272006-10-21 10:24:20 -07002263}
2264
2265/*
2266 * This helper attempts to cope with remotely renamed directories
2267 *
2268 * It assumes that the caller is already holding
Nick Pigginb5c84bf2011-01-07 17:49:38 +11002269 * dentry->d_parent->d_inode->i_mutex and the dcache_inode_lock
Trond Myklebust9eaef272006-10-21 10:24:20 -07002270 *
2271 * Note: If ever the locking in lock_rename() changes, then please
2272 * remember to update this too...
Trond Myklebust9eaef272006-10-21 10:24:20 -07002273 */
2274static struct dentry *__d_unalias(struct dentry *dentry, struct dentry *alias)
Nick Pigginb23fb0a2011-01-07 17:49:35 +11002275 __releases(dcache_inode_lock)
Trond Myklebust9eaef272006-10-21 10:24:20 -07002276{
2277 struct mutex *m1 = NULL, *m2 = NULL;
2278 struct dentry *ret;
2279
2280 /* If alias and dentry share a parent, then no extra locks required */
2281 if (alias->d_parent == dentry->d_parent)
2282 goto out_unalias;
2283
2284 /* Check for loops */
2285 ret = ERR_PTR(-ELOOP);
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002286 if (d_ancestor(alias, dentry))
Trond Myklebust9eaef272006-10-21 10:24:20 -07002287 goto out_err;
2288
2289 /* See lock_rename() */
2290 ret = ERR_PTR(-EBUSY);
2291 if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
2292 goto out_err;
2293 m1 = &dentry->d_sb->s_vfs_rename_mutex;
2294 if (!mutex_trylock(&alias->d_parent->d_inode->i_mutex))
2295 goto out_err;
2296 m2 = &alias->d_parent->d_inode->i_mutex;
2297out_unalias:
Nick Pigginb5c84bf2011-01-07 17:49:38 +11002298 d_move(alias, dentry);
Trond Myklebust9eaef272006-10-21 10:24:20 -07002299 ret = alias;
2300out_err:
Nick Pigginb23fb0a2011-01-07 17:49:35 +11002301 spin_unlock(&dcache_inode_lock);
Trond Myklebust9eaef272006-10-21 10:24:20 -07002302 if (m2)
2303 mutex_unlock(m2);
2304 if (m1)
2305 mutex_unlock(m1);
2306 return ret;
2307}
2308
2309/*
David Howells770bfad2006-08-22 20:06:07 -04002310 * Prepare an anonymous dentry for life in the superblock's dentry tree as a
2311 * named dentry in place of the dentry to be replaced.
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002312 * returns with anon->d_lock held!
David Howells770bfad2006-08-22 20:06:07 -04002313 */
2314static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
2315{
2316 struct dentry *dparent, *aparent;
2317
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002318 dentry_lock_for_move(anon, dentry);
David Howells770bfad2006-08-22 20:06:07 -04002319
Nick Piggin31e6b012011-01-07 17:49:52 +11002320 write_seqcount_begin(&dentry->d_seq);
2321 write_seqcount_begin(&anon->d_seq);
2322
David Howells770bfad2006-08-22 20:06:07 -04002323 dparent = dentry->d_parent;
2324 aparent = anon->d_parent;
2325
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002326 switch_names(dentry, anon);
2327 swap(dentry->d_name.hash, anon->d_name.hash);
2328
David Howells770bfad2006-08-22 20:06:07 -04002329 dentry->d_parent = (aparent == anon) ? dentry : aparent;
2330 list_del(&dentry->d_u.d_child);
2331 if (!IS_ROOT(dentry))
2332 list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
2333 else
2334 INIT_LIST_HEAD(&dentry->d_u.d_child);
2335
2336 anon->d_parent = (dparent == dentry) ? anon : dparent;
2337 list_del(&anon->d_u.d_child);
2338 if (!IS_ROOT(anon))
2339 list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs);
2340 else
2341 INIT_LIST_HEAD(&anon->d_u.d_child);
2342
Nick Piggin31e6b012011-01-07 17:49:52 +11002343 write_seqcount_end(&dentry->d_seq);
2344 write_seqcount_end(&anon->d_seq);
2345
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002346 dentry_unlock_parents_for_move(anon, dentry);
2347 spin_unlock(&dentry->d_lock);
2348
2349 /* anon->d_lock still locked, returns locked */
David Howells770bfad2006-08-22 20:06:07 -04002350 anon->d_flags &= ~DCACHE_DISCONNECTED;
2351}
2352
2353/**
2354 * d_materialise_unique - introduce an inode into the tree
2355 * @dentry: candidate dentry
2356 * @inode: inode to bind to the dentry, to which aliases may be attached
2357 *
2358 * Introduces an dentry into the tree, substituting an extant disconnected
2359 * root directory alias in its place if there is one
2360 */
2361struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
2362{
Trond Myklebust9eaef272006-10-21 10:24:20 -07002363 struct dentry *actual;
David Howells770bfad2006-08-22 20:06:07 -04002364
2365 BUG_ON(!d_unhashed(dentry));
2366
David Howells770bfad2006-08-22 20:06:07 -04002367 if (!inode) {
2368 actual = dentry;
OGAWA Hirofumi360da902008-10-16 07:50:28 +09002369 __d_instantiate(dentry, NULL);
Nick Piggin357f8e62011-01-07 17:49:42 +11002370 d_rehash(actual);
2371 goto out_nolock;
David Howells770bfad2006-08-22 20:06:07 -04002372 }
2373
Nick Piggin357f8e62011-01-07 17:49:42 +11002374 spin_lock(&dcache_inode_lock);
2375
Trond Myklebust9eaef272006-10-21 10:24:20 -07002376 if (S_ISDIR(inode->i_mode)) {
2377 struct dentry *alias;
David Howells770bfad2006-08-22 20:06:07 -04002378
Trond Myklebust9eaef272006-10-21 10:24:20 -07002379 /* Does an aliased dentry already exist? */
2380 alias = __d_find_alias(inode, 0);
2381 if (alias) {
2382 actual = alias;
2383 /* Is this an anonymous mountpoint that we could splice
2384 * into our tree? */
2385 if (IS_ROOT(alias)) {
Trond Myklebust9eaef272006-10-21 10:24:20 -07002386 __d_materialise_dentry(dentry, alias);
2387 __d_drop(alias);
2388 goto found;
2389 }
2390 /* Nope, but we must(!) avoid directory aliasing */
2391 actual = __d_unalias(dentry, alias);
2392 if (IS_ERR(actual))
2393 dput(alias);
2394 goto out_nolock;
2395 }
David Howells770bfad2006-08-22 20:06:07 -04002396 }
2397
2398 /* Add a unique reference */
2399 actual = __d_instantiate_unique(dentry, inode);
2400 if (!actual)
2401 actual = dentry;
Nick Piggin357f8e62011-01-07 17:49:42 +11002402 else
2403 BUG_ON(!d_unhashed(actual));
David Howells770bfad2006-08-22 20:06:07 -04002404
David Howells770bfad2006-08-22 20:06:07 -04002405 spin_lock(&actual->d_lock);
2406found:
2407 _d_rehash(actual);
2408 spin_unlock(&actual->d_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +11002409 spin_unlock(&dcache_inode_lock);
Trond Myklebust9eaef272006-10-21 10:24:20 -07002410out_nolock:
David Howells770bfad2006-08-22 20:06:07 -04002411 if (actual == dentry) {
2412 security_d_instantiate(dentry, inode);
2413 return NULL;
2414 }
2415
2416 iput(inode);
2417 return actual;
David Howells770bfad2006-08-22 20:06:07 -04002418}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002419EXPORT_SYMBOL_GPL(d_materialise_unique);
David Howells770bfad2006-08-22 20:06:07 -04002420
Miklos Szeredicdd16d02008-06-23 18:11:53 +02002421static int prepend(char **buffer, int *buflen, const char *str, int namelen)
Ram Pai6092d042008-03-27 13:06:20 +01002422{
2423 *buflen -= namelen;
2424 if (*buflen < 0)
2425 return -ENAMETOOLONG;
2426 *buffer -= namelen;
2427 memcpy(*buffer, str, namelen);
2428 return 0;
2429}
2430
Miklos Szeredicdd16d02008-06-23 18:11:53 +02002431static int prepend_name(char **buffer, int *buflen, struct qstr *name)
2432{
2433 return prepend(buffer, buflen, name->name, name->len);
2434}
2435
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436/**
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002437 * Prepend path string to a buffer
2438 *
2439 * @path: the dentry/vfsmount to report
2440 * @root: root vfsmnt/dentry (may be modified by this function)
2441 * @buffer: pointer to the end of the buffer
2442 * @buflen: pointer to buffer length
2443 *
Nick Piggin949854d2011-01-07 17:49:37 +11002444 * Caller holds the rename_lock.
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002445 *
2446 * If path is not reachable from the supplied root, then the value of
2447 * root is changed (without modifying refcounts).
2448 */
2449static int prepend_path(const struct path *path, struct path *root,
2450 char **buffer, int *buflen)
2451{
2452 struct dentry *dentry = path->dentry;
2453 struct vfsmount *vfsmnt = path->mnt;
2454 bool slash = false;
2455 int error = 0;
2456
Nick Piggin99b7db72010-08-18 04:37:39 +10002457 br_read_lock(vfsmount_lock);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002458 while (dentry != root->dentry || vfsmnt != root->mnt) {
2459 struct dentry * parent;
2460
2461 if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
2462 /* Global root? */
2463 if (vfsmnt->mnt_parent == vfsmnt) {
2464 goto global_root;
2465 }
2466 dentry = vfsmnt->mnt_mountpoint;
2467 vfsmnt = vfsmnt->mnt_parent;
2468 continue;
2469 }
2470 parent = dentry->d_parent;
2471 prefetch(parent);
Nick Piggin9abca362011-01-07 17:49:36 +11002472 spin_lock(&dentry->d_lock);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002473 error = prepend_name(buffer, buflen, &dentry->d_name);
Nick Piggin9abca362011-01-07 17:49:36 +11002474 spin_unlock(&dentry->d_lock);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002475 if (!error)
2476 error = prepend(buffer, buflen, "/", 1);
2477 if (error)
2478 break;
2479
2480 slash = true;
2481 dentry = parent;
2482 }
2483
2484out:
2485 if (!error && !slash)
2486 error = prepend(buffer, buflen, "/", 1);
2487
Nick Piggin99b7db72010-08-18 04:37:39 +10002488 br_read_unlock(vfsmount_lock);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002489 return error;
2490
2491global_root:
2492 /*
2493 * Filesystems needing to implement special "root names"
2494 * should do so with ->d_dname()
2495 */
2496 if (IS_ROOT(dentry) &&
2497 (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) {
2498 WARN(1, "Root dentry has weird name <%.*s>\n",
2499 (int) dentry->d_name.len, dentry->d_name.name);
2500 }
2501 root->mnt = vfsmnt;
2502 root->dentry = dentry;
2503 goto out;
2504}
2505
2506/**
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +02002507 * __d_path - return the path of a dentry
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002508 * @path: the dentry/vfsmount to report
2509 * @root: root vfsmnt/dentry (may be modified by this function)
Randy Dunlapcd956a12010-08-14 13:05:31 -07002510 * @buf: buffer to return value in
Linus Torvalds1da177e2005-04-16 15:20:36 -07002511 * @buflen: buffer length
2512 *
Miklos Szerediffd1f4e2010-08-10 11:41:40 +02002513 * Convert a dentry into an ASCII path name.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002514 *
Arjan van de Ven52afeef2008-12-01 14:35:00 -08002515 * Returns a pointer into the buffer or an error code if the
2516 * path was too long.
Linus Torvalds552ce542007-02-13 12:08:18 -08002517 *
Christoph Hellwigbe148242010-10-10 05:36:21 -04002518 * "buflen" should be positive.
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002519 *
2520 * If path is not reachable from the supplied root, then the value of
2521 * root is changed (without modifying refcounts).
Linus Torvalds1da177e2005-04-16 15:20:36 -07002522 */
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002523char *__d_path(const struct path *path, struct path *root,
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002524 char *buf, int buflen)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002525{
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002526 char *res = buf + buflen;
2527 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002528
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002529 prepend(&res, &buflen, "\0", 1);
Nick Piggin949854d2011-01-07 17:49:37 +11002530 write_seqlock(&rename_lock);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002531 error = prepend_path(path, root, &res, &buflen);
Nick Piggin949854d2011-01-07 17:49:37 +11002532 write_sequnlock(&rename_lock);
Christoph Hellwigbe148242010-10-10 05:36:21 -04002533
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002534 if (error)
2535 return ERR_PTR(error);
Miklos Szeredif2eb6572010-08-10 11:41:39 +02002536 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537}
2538
Miklos Szerediffd1f4e2010-08-10 11:41:40 +02002539/*
2540 * same as __d_path but appends "(deleted)" for unlinked files.
2541 */
2542static int path_with_deleted(const struct path *path, struct path *root,
2543 char **buf, int *buflen)
2544{
2545 prepend(buf, buflen, "\0", 1);
2546 if (d_unlinked(path->dentry)) {
2547 int error = prepend(buf, buflen, " (deleted)", 10);
2548 if (error)
2549 return error;
2550 }
2551
2552 return prepend_path(path, root, buf, buflen);
2553}
2554
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002555static int prepend_unreachable(char **buffer, int *buflen)
2556{
2557 return prepend(buffer, buflen, "(unreachable)", 13);
2558}
2559
Jan Bluncka03a8a702008-02-14 19:38:32 -08002560/**
2561 * d_path - return the path of a dentry
Jan Blunckcf28b482008-02-14 19:38:44 -08002562 * @path: path to report
Jan Bluncka03a8a702008-02-14 19:38:32 -08002563 * @buf: buffer to return value in
2564 * @buflen: buffer length
2565 *
2566 * Convert a dentry into an ASCII path name. If the entry has been deleted
2567 * the string " (deleted)" is appended. Note that this is ambiguous.
2568 *
Arjan van de Ven52afeef2008-12-01 14:35:00 -08002569 * Returns a pointer into the buffer or an error code if the path was
2570 * too long. Note: Callers should use the returned pointer, not the passed
2571 * in buffer, to use the name! The implementation often starts at an offset
2572 * into the buffer, and may leave 0 bytes at the start.
Jan Bluncka03a8a702008-02-14 19:38:32 -08002573 *
Miklos Szeredi31f3e0b2008-06-23 18:11:52 +02002574 * "buflen" should be positive.
Jan Bluncka03a8a702008-02-14 19:38:32 -08002575 */
Jan Engelhardt20d4fdc2008-06-09 16:40:36 -07002576char *d_path(const struct path *path, char *buf, int buflen)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577{
Miklos Szerediffd1f4e2010-08-10 11:41:40 +02002578 char *res = buf + buflen;
Jan Blunck6ac08c32008-02-14 19:34:38 -08002579 struct path root;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002580 struct path tmp;
Miklos Szerediffd1f4e2010-08-10 11:41:40 +02002581 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582
Eric Dumazetc23fbb62007-05-08 00:26:18 -07002583 /*
2584 * We have various synthetic filesystems that never get mounted. On
2585 * these filesystems dentries are never used for lookup purposes, and
2586 * thus don't need to be hashed. They also don't need a name until a
2587 * user wants to identify the object in /proc/pid/fd/. The little hack
2588 * below allows us to generate a name for these objects on demand:
2589 */
Jan Blunckcf28b482008-02-14 19:38:44 -08002590 if (path->dentry->d_op && path->dentry->d_op->d_dname)
2591 return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
Eric Dumazetc23fbb62007-05-08 00:26:18 -07002592
Miklos Szeredif7ad3c62010-08-10 11:41:36 +02002593 get_fs_root(current->fs, &root);
Nick Piggin949854d2011-01-07 17:49:37 +11002594 write_seqlock(&rename_lock);
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002595 tmp = root;
Miklos Szerediffd1f4e2010-08-10 11:41:40 +02002596 error = path_with_deleted(path, &tmp, &res, &buflen);
2597 if (error)
2598 res = ERR_PTR(error);
Nick Piggin949854d2011-01-07 17:49:37 +11002599 write_sequnlock(&rename_lock);
Jan Blunck6ac08c32008-02-14 19:34:38 -08002600 path_put(&root);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002601 return res;
2602}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002603EXPORT_SYMBOL(d_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002604
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002605/**
2606 * d_path_with_unreachable - return the path of a dentry
2607 * @path: path to report
2608 * @buf: buffer to return value in
2609 * @buflen: buffer length
2610 *
2611 * The difference from d_path() is that this prepends "(unreachable)"
2612 * to paths which are unreachable from the current process' root.
2613 */
2614char *d_path_with_unreachable(const struct path *path, char *buf, int buflen)
2615{
2616 char *res = buf + buflen;
2617 struct path root;
2618 struct path tmp;
2619 int error;
2620
2621 if (path->dentry->d_op && path->dentry->d_op->d_dname)
2622 return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
2623
2624 get_fs_root(current->fs, &root);
Nick Piggin949854d2011-01-07 17:49:37 +11002625 write_seqlock(&rename_lock);
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002626 tmp = root;
2627 error = path_with_deleted(path, &tmp, &res, &buflen);
2628 if (!error && !path_equal(&tmp, &root))
2629 error = prepend_unreachable(&res, &buflen);
Nick Piggin949854d2011-01-07 17:49:37 +11002630 write_sequnlock(&rename_lock);
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002631 path_put(&root);
2632 if (error)
2633 res = ERR_PTR(error);
2634
2635 return res;
2636}
2637
Linus Torvalds1da177e2005-04-16 15:20:36 -07002638/*
Eric Dumazetc23fbb62007-05-08 00:26:18 -07002639 * Helper function for dentry_operations.d_dname() members
2640 */
2641char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
2642 const char *fmt, ...)
2643{
2644 va_list args;
2645 char temp[64];
2646 int sz;
2647
2648 va_start(args, fmt);
2649 sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1;
2650 va_end(args);
2651
2652 if (sz > sizeof(temp) || sz > buflen)
2653 return ERR_PTR(-ENAMETOOLONG);
2654
2655 buffer += buflen - sz;
2656 return memcpy(buffer, temp, sz);
2657}
2658
2659/*
Ram Pai6092d042008-03-27 13:06:20 +01002660 * Write full pathname from the root of the filesystem into the buffer.
2661 */
Nick Pigginec2447c2011-01-07 17:49:29 +11002662static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
Ram Pai6092d042008-03-27 13:06:20 +01002663{
2664 char *end = buf + buflen;
2665 char *retval;
2666
Ram Pai6092d042008-03-27 13:06:20 +01002667 prepend(&end, &buflen, "\0", 1);
Ram Pai6092d042008-03-27 13:06:20 +01002668 if (buflen < 1)
2669 goto Elong;
2670 /* Get '/' right */
2671 retval = end-1;
2672 *retval = '/';
2673
Miklos Szeredicdd16d02008-06-23 18:11:53 +02002674 while (!IS_ROOT(dentry)) {
2675 struct dentry *parent = dentry->d_parent;
Nick Piggin9abca362011-01-07 17:49:36 +11002676 int error;
Ram Pai6092d042008-03-27 13:06:20 +01002677
Ram Pai6092d042008-03-27 13:06:20 +01002678 prefetch(parent);
Nick Piggin9abca362011-01-07 17:49:36 +11002679 spin_lock(&dentry->d_lock);
2680 error = prepend_name(&end, &buflen, &dentry->d_name);
2681 spin_unlock(&dentry->d_lock);
2682 if (error != 0 || prepend(&end, &buflen, "/", 1) != 0)
Ram Pai6092d042008-03-27 13:06:20 +01002683 goto Elong;
2684
2685 retval = end;
2686 dentry = parent;
2687 }
Al Viroc1031352010-06-06 22:31:14 -04002688 return retval;
2689Elong:
2690 return ERR_PTR(-ENAMETOOLONG);
2691}
Nick Pigginec2447c2011-01-07 17:49:29 +11002692
2693char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
2694{
2695 char *retval;
2696
Nick Piggin949854d2011-01-07 17:49:37 +11002697 write_seqlock(&rename_lock);
Nick Pigginec2447c2011-01-07 17:49:29 +11002698 retval = __dentry_path(dentry, buf, buflen);
Nick Piggin949854d2011-01-07 17:49:37 +11002699 write_sequnlock(&rename_lock);
Nick Pigginec2447c2011-01-07 17:49:29 +11002700
2701 return retval;
2702}
2703EXPORT_SYMBOL(dentry_path_raw);
Al Viroc1031352010-06-06 22:31:14 -04002704
2705char *dentry_path(struct dentry *dentry, char *buf, int buflen)
2706{
2707 char *p = NULL;
2708 char *retval;
2709
Nick Piggin949854d2011-01-07 17:49:37 +11002710 write_seqlock(&rename_lock);
Al Viroc1031352010-06-06 22:31:14 -04002711 if (d_unlinked(dentry)) {
2712 p = buf + buflen;
2713 if (prepend(&p, &buflen, "//deleted", 10) != 0)
2714 goto Elong;
2715 buflen++;
2716 }
2717 retval = __dentry_path(dentry, buf, buflen);
Nick Piggin949854d2011-01-07 17:49:37 +11002718 write_sequnlock(&rename_lock);
Al Viroc1031352010-06-06 22:31:14 -04002719 if (!IS_ERR(retval) && p)
2720 *p = '/'; /* restore '/' overriden with '\0' */
Ram Pai6092d042008-03-27 13:06:20 +01002721 return retval;
2722Elong:
Ram Pai6092d042008-03-27 13:06:20 +01002723 return ERR_PTR(-ENAMETOOLONG);
2724}
2725
2726/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002727 * NOTE! The user-level library version returns a
2728 * character pointer. The kernel system call just
2729 * returns the length of the buffer filled (which
2730 * includes the ending '\0' character), or a negative
2731 * error value. So libc would do something like
2732 *
2733 * char *getcwd(char * buf, size_t size)
2734 * {
2735 * int retval;
2736 *
2737 * retval = sys_getcwd(buf, size);
2738 * if (retval >= 0)
2739 * return buf;
2740 * errno = -retval;
2741 * return NULL;
2742 * }
2743 */
Heiko Carstens3cdad422009-01-14 14:14:22 +01002744SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002745{
Linus Torvalds552ce542007-02-13 12:08:18 -08002746 int error;
Jan Blunck6ac08c32008-02-14 19:34:38 -08002747 struct path pwd, root;
Linus Torvalds552ce542007-02-13 12:08:18 -08002748 char *page = (char *) __get_free_page(GFP_USER);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002749
2750 if (!page)
2751 return -ENOMEM;
2752
Miklos Szeredif7ad3c62010-08-10 11:41:36 +02002753 get_fs_root_and_pwd(current->fs, &root, &pwd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002754
Linus Torvalds552ce542007-02-13 12:08:18 -08002755 error = -ENOENT;
Nick Piggin949854d2011-01-07 17:49:37 +11002756 write_seqlock(&rename_lock);
Alexey Dobriyanf3da3922009-05-04 03:32:03 +04002757 if (!d_unlinked(pwd.dentry)) {
Linus Torvalds552ce542007-02-13 12:08:18 -08002758 unsigned long len;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +01002759 struct path tmp = root;
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002760 char *cwd = page + PAGE_SIZE;
2761 int buflen = PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002762
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002763 prepend(&cwd, &buflen, "\0", 1);
2764 error = prepend_path(&pwd, &tmp, &cwd, &buflen);
Nick Piggin949854d2011-01-07 17:49:37 +11002765 write_sequnlock(&rename_lock);
Linus Torvalds552ce542007-02-13 12:08:18 -08002766
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002767 if (error)
Linus Torvalds552ce542007-02-13 12:08:18 -08002768 goto out;
2769
Miklos Szeredi8df9d1a2010-08-10 11:41:41 +02002770 /* Unreachable from current root */
2771 if (!path_equal(&tmp, &root)) {
2772 error = prepend_unreachable(&cwd, &buflen);
2773 if (error)
2774 goto out;
2775 }
2776
Linus Torvalds552ce542007-02-13 12:08:18 -08002777 error = -ERANGE;
2778 len = PAGE_SIZE + page - cwd;
2779 if (len <= size) {
2780 error = len;
2781 if (copy_to_user(buf, cwd, len))
2782 error = -EFAULT;
2783 }
Nick Piggin949854d2011-01-07 17:49:37 +11002784 } else {
2785 write_sequnlock(&rename_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11002786 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002787
2788out:
Jan Blunck6ac08c32008-02-14 19:34:38 -08002789 path_put(&pwd);
2790 path_put(&root);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002791 free_page((unsigned long) page);
2792 return error;
2793}
2794
2795/*
2796 * Test whether new_dentry is a subdirectory of old_dentry.
2797 *
2798 * Trivially implemented using the dcache structure
2799 */
2800
2801/**
2802 * is_subdir - is new dentry a subdirectory of old_dentry
2803 * @new_dentry: new dentry
2804 * @old_dentry: old dentry
2805 *
2806 * Returns 1 if new_dentry is a subdirectory of the parent (at any depth).
2807 * Returns 0 otherwise.
2808 * Caller must ensure that "new_dentry" is pinned before calling is_subdir()
2809 */
2810
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002811int is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002812{
2813 int result;
Nick Piggin949854d2011-01-07 17:49:37 +11002814 unsigned seq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002815
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002816 if (new_dentry == old_dentry)
2817 return 1;
2818
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002819 do {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002820 /* for restarting inner loop in case of seq retry */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002821 seq = read_seqbegin(&rename_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11002822 /*
2823 * Need rcu_readlock to protect against the d_parent trashing
2824 * due to d_move
2825 */
2826 rcu_read_lock();
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002827 if (d_ancestor(old_dentry, new_dentry))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002828 result = 1;
OGAWA Hirofumie2761a12008-10-16 07:50:28 +09002829 else
2830 result = 0;
Nick Piggin949854d2011-01-07 17:49:37 +11002831 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002832 } while (read_seqretry(&rename_lock, seq));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002833
2834 return result;
2835}
2836
Al Viro2096f752010-01-30 13:16:21 -05002837int path_is_under(struct path *path1, struct path *path2)
2838{
2839 struct vfsmount *mnt = path1->mnt;
2840 struct dentry *dentry = path1->dentry;
2841 int res;
Nick Piggin99b7db72010-08-18 04:37:39 +10002842
2843 br_read_lock(vfsmount_lock);
Al Viro2096f752010-01-30 13:16:21 -05002844 if (mnt != path2->mnt) {
2845 for (;;) {
2846 if (mnt->mnt_parent == mnt) {
Nick Piggin99b7db72010-08-18 04:37:39 +10002847 br_read_unlock(vfsmount_lock);
Al Viro2096f752010-01-30 13:16:21 -05002848 return 0;
2849 }
2850 if (mnt->mnt_parent == path2->mnt)
2851 break;
2852 mnt = mnt->mnt_parent;
2853 }
2854 dentry = mnt->mnt_mountpoint;
2855 }
2856 res = is_subdir(dentry, path2->dentry);
Nick Piggin99b7db72010-08-18 04:37:39 +10002857 br_read_unlock(vfsmount_lock);
Al Viro2096f752010-01-30 13:16:21 -05002858 return res;
2859}
2860EXPORT_SYMBOL(path_is_under);
2861
Linus Torvalds1da177e2005-04-16 15:20:36 -07002862void d_genocide(struct dentry *root)
2863{
Nick Piggin949854d2011-01-07 17:49:37 +11002864 struct dentry *this_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002865 struct list_head *next;
Nick Piggin949854d2011-01-07 17:49:37 +11002866 unsigned seq;
Nick Piggin58db63d2011-01-07 17:49:39 +11002867 int locked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002868
Nick Piggin949854d2011-01-07 17:49:37 +11002869 seq = read_seqbegin(&rename_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11002870again:
2871 this_parent = root;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002872 spin_lock(&this_parent->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002873repeat:
2874 next = this_parent->d_subdirs.next;
2875resume:
2876 while (next != &this_parent->d_subdirs) {
2877 struct list_head *tmp = next;
Eric Dumazet5160ee62006-01-08 01:03:32 -08002878 struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002879 next = tmp->next;
Nick Piggin949854d2011-01-07 17:49:37 +11002880
Nick Pigginda502952011-01-07 17:49:33 +11002881 spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
2882 if (d_unhashed(dentry) || !dentry->d_inode) {
2883 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002884 continue;
Nick Pigginda502952011-01-07 17:49:33 +11002885 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002886 if (!list_empty(&dentry->d_subdirs)) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002887 spin_unlock(&this_parent->d_lock);
2888 spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002889 this_parent = dentry;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002890 spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002891 goto repeat;
2892 }
Nick Piggin949854d2011-01-07 17:49:37 +11002893 if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
2894 dentry->d_flags |= DCACHE_GENOCIDE;
2895 dentry->d_count--;
2896 }
Nick Pigginb7ab39f2011-01-07 17:49:32 +11002897 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002898 }
2899 if (this_parent != root) {
Nick Piggin949854d2011-01-07 17:49:37 +11002900 struct dentry *tmp;
2901 struct dentry *child;
2902
2903 tmp = this_parent->d_parent;
2904 if (!(this_parent->d_flags & DCACHE_GENOCIDE)) {
2905 this_parent->d_flags |= DCACHE_GENOCIDE;
2906 this_parent->d_count--;
2907 }
2908 rcu_read_lock();
Nick Pigginb7ab39f2011-01-07 17:49:32 +11002909 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11002910 child = this_parent;
2911 this_parent = tmp;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002912 spin_lock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11002913 /* might go back up the wrong parent if we have had a rename
2914 * or deletion */
2915 if (this_parent != child->d_parent ||
Nick Piggin58db63d2011-01-07 17:49:39 +11002916 (!locked && read_seqretry(&rename_lock, seq))) {
Nick Piggin949854d2011-01-07 17:49:37 +11002917 spin_unlock(&this_parent->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +11002918 rcu_read_unlock();
2919 goto rename_retry;
2920 }
2921 rcu_read_unlock();
2922 next = child->d_u.d_child.next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002923 goto resume;
2924 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +11002925 spin_unlock(&this_parent->d_lock);
Nick Piggin58db63d2011-01-07 17:49:39 +11002926 if (!locked && read_seqretry(&rename_lock, seq))
Nick Piggin949854d2011-01-07 17:49:37 +11002927 goto rename_retry;
Nick Piggin58db63d2011-01-07 17:49:39 +11002928 if (locked)
2929 write_sequnlock(&rename_lock);
2930 return;
2931
2932rename_retry:
2933 locked = 1;
2934 write_seqlock(&rename_lock);
2935 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002936}
2937
2938/**
2939 * find_inode_number - check for dentry with name
2940 * @dir: directory to check
2941 * @name: Name to find.
2942 *
2943 * Check whether a dentry already exists for the given name,
2944 * and return the inode number if it has an inode. Otherwise
2945 * 0 is returned.
2946 *
2947 * This routine is used to post-process directory listings for
2948 * filesystems using synthetic inode numbers, and is necessary
2949 * to keep getcwd() working.
2950 */
2951
2952ino_t find_inode_number(struct dentry *dir, struct qstr *name)
2953{
2954 struct dentry * dentry;
2955 ino_t ino = 0;
2956
Eric W. Biederman3e7e2412006-03-31 02:31:43 -08002957 dentry = d_hash_and_lookup(dir, name);
2958 if (dentry) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002959 if (dentry->d_inode)
2960 ino = dentry->d_inode->i_ino;
2961 dput(dentry);
2962 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002963 return ino;
2964}
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07002965EXPORT_SYMBOL(find_inode_number);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002966
2967static __initdata unsigned long dhash_entries;
2968static int __init set_dhash_entries(char *str)
2969{
2970 if (!str)
2971 return 0;
2972 dhash_entries = simple_strtoul(str, &str, 0);
2973 return 1;
2974}
2975__setup("dhash_entries=", set_dhash_entries);
2976
2977static void __init dcache_init_early(void)
2978{
2979 int loop;
2980
2981 /* If hashes are distributed across NUMA nodes, defer
2982 * hash allocation until vmalloc space is available.
2983 */
2984 if (hashdist)
2985 return;
2986
2987 dentry_hashtable =
2988 alloc_large_system_hash("Dentry cache",
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002989 sizeof(struct dcache_hash_bucket),
Linus Torvalds1da177e2005-04-16 15:20:36 -07002990 dhash_entries,
2991 13,
2992 HASH_EARLY,
2993 &d_hash_shift,
2994 &d_hash_mask,
2995 0);
2996
2997 for (loop = 0; loop < (1 << d_hash_shift); loop++)
Nick Pigginceb5bdc2011-01-07 17:50:05 +11002998 INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002999}
3000
Denis Cheng74bf17c2007-10-16 23:26:30 -07003001static void __init dcache_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003002{
3003 int loop;
3004
3005 /*
3006 * A constructor could be added for stable state like the lists,
3007 * but it is probably not worth it because of the cache nature
3008 * of the dcache.
3009 */
Christoph Lameter0a31bd52007-05-06 14:49:57 -07003010 dentry_cache = KMEM_CACHE(dentry,
3011 SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003012
Rusty Russell8e1f9362007-07-17 04:03:17 -07003013 register_shrinker(&dcache_shrinker);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003014
3015 /* Hash may have been set up in dcache_init_early */
3016 if (!hashdist)
3017 return;
3018
3019 dentry_hashtable =
3020 alloc_large_system_hash("Dentry cache",
Nick Pigginceb5bdc2011-01-07 17:50:05 +11003021 sizeof(struct dcache_hash_bucket),
Linus Torvalds1da177e2005-04-16 15:20:36 -07003022 dhash_entries,
3023 13,
3024 0,
3025 &d_hash_shift,
3026 &d_hash_mask,
3027 0);
3028
3029 for (loop = 0; loop < (1 << d_hash_shift); loop++)
Nick Pigginceb5bdc2011-01-07 17:50:05 +11003030 INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003031}
3032
3033/* SLAB cache for __getname() consumers */
Christoph Lametere18b8902006-12-06 20:33:20 -08003034struct kmem_cache *names_cachep __read_mostly;
H Hartley Sweetenec4f8602010-01-05 13:45:18 -07003035EXPORT_SYMBOL(names_cachep);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003036
Linus Torvalds1da177e2005-04-16 15:20:36 -07003037EXPORT_SYMBOL(d_genocide);
3038
Linus Torvalds1da177e2005-04-16 15:20:36 -07003039void __init vfs_caches_init_early(void)
3040{
3041 dcache_init_early();
3042 inode_init_early();
3043}
3044
3045void __init vfs_caches_init(unsigned long mempages)
3046{
3047 unsigned long reserve;
3048
3049 /* Base hash sizes on available memory, with a reserve equal to
3050 150% of current kernel size */
3051
3052 reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1);
3053 mempages -= reserve;
3054
3055 names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09003056 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003057
Denis Cheng74bf17c2007-10-16 23:26:30 -07003058 dcache_init();
3059 inode_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003060 files_init(mempages);
Denis Cheng74bf17c2007-10-16 23:26:30 -07003061 mnt_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003062 bdev_cache_init();
3063 chrdev_init();
3064}