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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/inode.c
3 *
4 * (C) 1997 Linus Torvalds
5 */
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/fs.h>
8#include <linux/mm.h>
9#include <linux/dcache.h>
10#include <linux/init.h>
11#include <linux/quotaops.h>
12#include <linux/slab.h>
13#include <linux/writeback.h>
14#include <linux/module.h>
15#include <linux/backing-dev.h>
16#include <linux/wait.h>
17#include <linux/hash.h>
18#include <linux/swap.h>
19#include <linux/security.h>
20#include <linux/pagemap.h>
21#include <linux/cdev.h>
22#include <linux/bootmem.h>
Robert Love0eeca282005-07-12 17:06:03 -040023#include <linux/inotify.h>
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -080024#include <linux/mount.h>
Arjan van de Venefaee192009-01-06 07:20:54 -080025#include <linux/async.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
27/*
28 * This is needed for the following functions:
29 * - inode_has_buffers
30 * - invalidate_inode_buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 * - invalidate_bdev
32 *
33 * FIXME: remove all knowledge of the buffer layer from this file
34 */
35#include <linux/buffer_head.h>
36
37/*
38 * New inode.c implementation.
39 *
40 * This implementation has the basic premise of trying
41 * to be extremely low-overhead and SMP-safe, yet be
42 * simple enough to be "obviously correct".
43 *
44 * Famous last words.
45 */
46
47/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
48
49/* #define INODE_PARANOIA 1 */
50/* #define INODE_DEBUG 1 */
51
52/*
53 * Inode lookup is no longer as critical as it used to be:
54 * most of the lookups are going to be through the dcache.
55 */
56#define I_HASHBITS i_hash_shift
57#define I_HASHMASK i_hash_mask
58
Eric Dumazetfa3536c2006-03-26 01:37:24 -080059static unsigned int i_hash_mask __read_mostly;
60static unsigned int i_hash_shift __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62/*
63 * Each inode can be on two separate lists. One is
64 * the hash list of the inode, used for lookups. The
65 * other linked list is the "type" list:
66 * "in_use" - valid inode, i_count > 0, i_nlink > 0
67 * "dirty" - as "in_use" but also dirty
68 * "unused" - valid inode, i_count = 0
69 *
70 * A "dirty" list is maintained for each super block,
71 * allowing for low-overhead inode sync() operations.
72 */
73
74LIST_HEAD(inode_in_use);
75LIST_HEAD(inode_unused);
Eric Dumazetfa3536c2006-03-26 01:37:24 -080076static struct hlist_head *inode_hashtable __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077
78/*
79 * A simple spinlock to protect the list manipulations.
80 *
81 * NOTE! You also have to own the lock if you change
82 * the i_state of an inode while it is in use..
83 */
84DEFINE_SPINLOCK(inode_lock);
85
86/*
Ingo Molnarf24075b2006-03-23 03:00:34 -080087 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 * icache shrinking path, and the umount path. Without this exclusion,
89 * by the time prune_icache calls iput for the inode whose pages it has
90 * been invalidating, or by the time it calls clear_inode & destroy_inode
91 * from its final dispose_list, the struct super_block they refer to
92 * (for inode->i_sb->s_op) may already have been freed and reused.
93 */
Adrian Bunkbdfc3262006-03-25 03:06:56 -080094static DEFINE_MUTEX(iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96/*
97 * Statistics gathering..
98 */
99struct inodes_stat_t inodes_stat;
100
Christoph Lametere18b8902006-12-06 20:33:20 -0800101static struct kmem_cache * inode_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
Joern Engel1c0eeaf2007-10-16 23:30:44 -0700103static void wake_up_inode(struct inode *inode)
104{
105 /*
106 * Prevent speculative execution through spin_unlock(&inode_lock);
107 */
108 smp_mb();
109 wake_up_bit(&inode->i_state, __I_LOCK);
110}
111
David Chinner2cb15992008-10-30 17:32:23 +1100112/**
113 * inode_init_always - perform inode structure intialisation
Randy Dunlap0bc02f32009-01-06 14:41:13 -0800114 * @sb: superblock inode belongs to
115 * @inode: inode to initialise
David Chinner2cb15992008-10-30 17:32:23 +1100116 *
117 * These are initializations that need to be done on every inode
118 * allocation as the fields are not initialised by slab allocation.
119 */
120struct inode *inode_init_always(struct super_block *sb, struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121{
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700122 static const struct address_space_operations empty_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 static struct inode_operations empty_iops;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800124 static const struct file_operations empty_fops;
David Chinner2cb15992008-10-30 17:32:23 +1100125
126 struct address_space * const mapping = &inode->i_data;
127
128 inode->i_sb = sb;
129 inode->i_blkbits = sb->s_blocksize_bits;
130 inode->i_flags = 0;
131 atomic_set(&inode->i_count, 1);
132 inode->i_op = &empty_iops;
133 inode->i_fop = &empty_fops;
134 inode->i_nlink = 1;
Al Viro56ff5ef2008-12-09 09:34:39 -0500135 inode->i_uid = 0;
136 inode->i_gid = 0;
David Chinner2cb15992008-10-30 17:32:23 +1100137 atomic_set(&inode->i_writecount, 0);
138 inode->i_size = 0;
139 inode->i_blocks = 0;
140 inode->i_bytes = 0;
141 inode->i_generation = 0;
142#ifdef CONFIG_QUOTA
143 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
144#endif
145 inode->i_pipe = NULL;
146 inode->i_bdev = NULL;
147 inode->i_cdev = NULL;
148 inode->i_rdev = 0;
149 inode->dirtied_when = 0;
150 if (security_inode_alloc(inode)) {
151 if (inode->i_sb->s_op->destroy_inode)
152 inode->i_sb->s_op->destroy_inode(inode);
153 else
154 kmem_cache_free(inode_cachep, (inode));
155 return NULL;
156 }
157
158 spin_lock_init(&inode->i_lock);
159 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
160
161 mutex_init(&inode->i_mutex);
162 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
163
164 init_rwsem(&inode->i_alloc_sem);
165 lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
166
167 mapping->a_ops = &empty_aops;
168 mapping->host = inode;
169 mapping->flags = 0;
Hugh Dickins3c1d4372009-01-06 14:39:23 -0800170 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
David Chinner2cb15992008-10-30 17:32:23 +1100171 mapping->assoc_mapping = NULL;
172 mapping->backing_dev_info = &default_backing_dev_info;
173 mapping->writeback_index = 0;
174
175 /*
176 * If the block_device provides a backing_dev_info for client
177 * inodes then use that. Otherwise the inode share the bdev's
178 * backing_dev_info.
179 */
180 if (sb->s_bdev) {
181 struct backing_dev_info *bdi;
182
183 bdi = sb->s_bdev->bd_inode_backing_dev_info;
184 if (!bdi)
185 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
186 mapping->backing_dev_info = bdi;
187 }
188 inode->i_private = NULL;
189 inode->i_mapping = mapping;
190
191 return inode;
192}
193EXPORT_SYMBOL(inode_init_always);
194
195static struct inode *alloc_inode(struct super_block *sb)
196{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 struct inode *inode;
198
199 if (sb->s_op->alloc_inode)
200 inode = sb->s_op->alloc_inode(sb);
201 else
David Chinner2cb15992008-10-30 17:32:23 +1100202 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
David Chinner2cb15992008-10-30 17:32:23 +1100204 if (inode)
205 return inode_init_always(sb, inode);
206 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207}
208
209void destroy_inode(struct inode *inode)
210{
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200211 BUG_ON(inode_has_buffers(inode));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 security_inode_free(inode);
213 if (inode->i_sb->s_op->destroy_inode)
214 inode->i_sb->s_op->destroy_inode(inode);
215 else
216 kmem_cache_free(inode_cachep, (inode));
217}
Christoph Hellwig087e3b02008-10-30 18:24:37 +1100218EXPORT_SYMBOL(destroy_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
220
221/*
222 * These are initializations that only need to be done
223 * once, because the fields are idempotent across use
224 * of the inode, so let the slab aware of that.
225 */
226void inode_init_once(struct inode *inode)
227{
228 memset(inode, 0, sizeof(*inode));
229 INIT_HLIST_NODE(&inode->i_hash);
230 INIT_LIST_HEAD(&inode->i_dentry);
231 INIT_LIST_HEAD(&inode->i_devices);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
Nick Piggin19fd6232008-07-25 19:45:32 -0700233 spin_lock_init(&inode->i_data.tree_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 spin_lock_init(&inode->i_data.i_mmap_lock);
235 INIT_LIST_HEAD(&inode->i_data.private_list);
236 spin_lock_init(&inode->i_data.private_lock);
237 INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
238 INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 i_size_ordered_init(inode);
Robert Love0eeca282005-07-12 17:06:03 -0400240#ifdef CONFIG_INOTIFY
241 INIT_LIST_HEAD(&inode->inotify_watches);
Ingo Molnard4f9af92006-03-23 03:00:30 -0800242 mutex_init(&inode->inotify_mutex);
Robert Love0eeca282005-07-12 17:06:03 -0400243#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
246EXPORT_SYMBOL(inode_init_once);
247
Alexey Dobriyan51cc5062008-07-25 19:45:34 -0700248static void init_once(void *foo)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249{
250 struct inode * inode = (struct inode *) foo;
251
Christoph Lametera35afb82007-05-16 22:10:57 -0700252 inode_init_once(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253}
254
255/*
256 * inode_lock must be held
257 */
258void __iget(struct inode * inode)
259{
260 if (atomic_read(&inode->i_count)) {
261 atomic_inc(&inode->i_count);
262 return;
263 }
264 atomic_inc(&inode->i_count);
Joern Engel1c0eeaf2007-10-16 23:30:44 -0700265 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 list_move(&inode->i_list, &inode_in_use);
267 inodes_stat.nr_unused--;
268}
269
270/**
271 * clear_inode - clear an inode
272 * @inode: inode to clear
273 *
274 * This is called by the filesystem to tell us
275 * that the inode is no longer useful. We just
276 * terminate it with extreme prejudice.
277 */
278void clear_inode(struct inode *inode)
279{
280 might_sleep();
281 invalidate_inode_buffers(inode);
282
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200283 BUG_ON(inode->i_data.nrpages);
284 BUG_ON(!(inode->i_state & I_FREEING));
285 BUG_ON(inode->i_state & I_CLEAR);
Joern Engel1c0eeaf2007-10-16 23:30:44 -0700286 inode_sync_wait(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 DQUOT_DROP(inode);
Christoph Hellwigacb0c852007-05-08 00:25:52 -0700288 if (inode->i_sb->s_op->clear_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 inode->i_sb->s_op->clear_inode(inode);
Theodore Ts'oeaf796e2006-09-27 01:50:48 -0700290 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 bd_forget(inode);
Theodore Ts'o577c4eb2006-09-27 01:50:49 -0700292 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 cd_forget(inode);
294 inode->i_state = I_CLEAR;
295}
296
297EXPORT_SYMBOL(clear_inode);
298
299/*
300 * dispose_list - dispose of the contents of a local list
301 * @head: the head of the list to free
302 *
303 * Dispose-list gets a local list with local inodes in it, so it doesn't
304 * need to worry about list corruption and SMP locks.
305 */
306static void dispose_list(struct list_head *head)
307{
308 int nr_disposed = 0;
309
310 while (!list_empty(head)) {
311 struct inode *inode;
312
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700313 inode = list_first_entry(head, struct inode, i_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 list_del(&inode->i_list);
315
316 if (inode->i_data.nrpages)
317 truncate_inode_pages(&inode->i_data, 0);
318 clear_inode(inode);
Artem B. Bityuckiy4120db42005-07-12 13:58:12 -0700319
320 spin_lock(&inode_lock);
321 hlist_del_init(&inode->i_hash);
322 list_del_init(&inode->i_sb_list);
323 spin_unlock(&inode_lock);
324
325 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 destroy_inode(inode);
327 nr_disposed++;
328 }
329 spin_lock(&inode_lock);
330 inodes_stat.nr_inodes -= nr_disposed;
331 spin_unlock(&inode_lock);
332}
333
334/*
335 * Invalidate all inodes for a device.
336 */
337static int invalidate_list(struct list_head *head, struct list_head *dispose)
338{
339 struct list_head *next;
340 int busy = 0, count = 0;
341
342 next = head->next;
343 for (;;) {
344 struct list_head * tmp = next;
345 struct inode * inode;
346
347 /*
348 * We can reschedule here without worrying about the list's
349 * consistency because the per-sb list of inodes must not
Ingo Molnarf24075b2006-03-23 03:00:34 -0800350 * change during umount anymore, and because iprune_mutex keeps
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 * shrink_icache_memory() away.
352 */
353 cond_resched_lock(&inode_lock);
354
355 next = next->next;
356 if (tmp == head)
357 break;
358 inode = list_entry(tmp, struct inode, i_sb_list);
359 invalidate_inode_buffers(inode);
360 if (!atomic_read(&inode->i_count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 list_move(&inode->i_list, dispose);
Nick Piggin7ef0d732009-03-12 14:31:38 -0700362 WARN_ON(inode->i_state & I_NEW);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 inode->i_state |= I_FREEING;
364 count++;
365 continue;
366 }
367 busy = 1;
368 }
369 /* only unused inodes may be cached with i_count zero */
370 inodes_stat.nr_unused -= count;
371 return busy;
372}
373
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374/**
375 * invalidate_inodes - discard the inodes on a device
376 * @sb: superblock
377 *
378 * Discard all of the inodes for a given superblock. If the discard
379 * fails because there are busy inodes then a non zero value is returned.
380 * If the discard is successful all the inodes have been discarded.
381 */
382int invalidate_inodes(struct super_block * sb)
383{
384 int busy;
385 LIST_HEAD(throw_away);
386
Ingo Molnarf24075b2006-03-23 03:00:34 -0800387 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 spin_lock(&inode_lock);
Robert Love0eeca282005-07-12 17:06:03 -0400389 inotify_unmount_inodes(&sb->s_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 busy = invalidate_list(&sb->s_inodes, &throw_away);
391 spin_unlock(&inode_lock);
392
393 dispose_list(&throw_away);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800394 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395
396 return busy;
397}
398
399EXPORT_SYMBOL(invalidate_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
401static int can_unuse(struct inode *inode)
402{
403 if (inode->i_state)
404 return 0;
405 if (inode_has_buffers(inode))
406 return 0;
407 if (atomic_read(&inode->i_count))
408 return 0;
409 if (inode->i_data.nrpages)
410 return 0;
411 return 1;
412}
413
414/*
415 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
416 * a temporary list and then are freed outside inode_lock by dispose_list().
417 *
418 * Any inodes which are pinned purely because of attached pagecache have their
419 * pagecache removed. We expect the final iput() on that inode to add it to
420 * the front of the inode_unused list. So look for it there and if the
421 * inode is still freeable, proceed. The right inode is found 99.9% of the
422 * time in testing on a 4-way.
423 *
424 * If the inode has metadata buffers attached to mapping->private_list then
425 * try to remove them.
426 */
427static void prune_icache(int nr_to_scan)
428{
429 LIST_HEAD(freeable);
430 int nr_pruned = 0;
431 int nr_scanned;
432 unsigned long reap = 0;
433
Ingo Molnarf24075b2006-03-23 03:00:34 -0800434 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 spin_lock(&inode_lock);
436 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
437 struct inode *inode;
438
439 if (list_empty(&inode_unused))
440 break;
441
442 inode = list_entry(inode_unused.prev, struct inode, i_list);
443
444 if (inode->i_state || atomic_read(&inode->i_count)) {
445 list_move(&inode->i_list, &inode_unused);
446 continue;
447 }
448 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
449 __iget(inode);
450 spin_unlock(&inode_lock);
451 if (remove_inode_buffers(inode))
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800452 reap += invalidate_mapping_pages(&inode->i_data,
453 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 iput(inode);
455 spin_lock(&inode_lock);
456
457 if (inode != list_entry(inode_unused.next,
458 struct inode, i_list))
459 continue; /* wrong inode or list_empty */
460 if (!can_unuse(inode))
461 continue;
462 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 list_move(&inode->i_list, &freeable);
Nick Piggin7ef0d732009-03-12 14:31:38 -0700464 WARN_ON(inode->i_state & I_NEW);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 inode->i_state |= I_FREEING;
466 nr_pruned++;
467 }
468 inodes_stat.nr_unused -= nr_pruned;
Christoph Lameterf8891e52006-06-30 01:55:45 -0700469 if (current_is_kswapd())
470 __count_vm_events(KSWAPD_INODESTEAL, reap);
471 else
472 __count_vm_events(PGINODESTEAL, reap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 spin_unlock(&inode_lock);
474
475 dispose_list(&freeable);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800476 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477}
478
479/*
480 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
481 * "unused" means that no dentries are referring to the inodes: the files are
482 * not open and the dcache references to those inodes have already been
483 * reclaimed.
484 *
485 * This function is passed the number of inodes to scan, and it returns the
486 * total number of remaining possibly-reclaimable inodes.
487 */
Al Viro27496a82005-10-21 03:20:48 -0400488static int shrink_icache_memory(int nr, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
490 if (nr) {
491 /*
492 * Nasty deadlock avoidance. We may hold various FS locks,
493 * and we don't want to recurse into the FS that called us
494 * in clear_inode() and friends..
495 */
496 if (!(gfp_mask & __GFP_FS))
497 return -1;
498 prune_icache(nr);
499 }
500 return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
501}
502
Rusty Russell8e1f9362007-07-17 04:03:17 -0700503static struct shrinker icache_shrinker = {
504 .shrink = shrink_icache_memory,
505 .seeks = DEFAULT_SEEKS,
506};
507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508static void __wait_on_freeing_inode(struct inode *inode);
509/*
510 * Called with the inode lock held.
511 * NOTE: we are not increasing the inode-refcount, you must call __iget()
512 * by hand after calling find_inode now! This simplifies iunique and won't
513 * add any additional branch in the common code.
514 */
515static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
516{
517 struct hlist_node *node;
518 struct inode * inode = NULL;
519
520repeat:
Matthias Kaehlckec5c8be32008-04-29 00:59:40 -0700521 hlist_for_each_entry(inode, node, head, i_hash) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 if (inode->i_sb != sb)
523 continue;
524 if (!test(inode, data))
525 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700526 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 __wait_on_freeing_inode(inode);
528 goto repeat;
529 }
530 break;
531 }
532 return node ? inode : NULL;
533}
534
535/*
536 * find_inode_fast is the fast path version of find_inode, see the comment at
537 * iget_locked for details.
538 */
539static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
540{
541 struct hlist_node *node;
542 struct inode * inode = NULL;
543
544repeat:
Matthias Kaehlckec5c8be32008-04-29 00:59:40 -0700545 hlist_for_each_entry(inode, node, head, i_hash) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 if (inode->i_ino != ino)
547 continue;
548 if (inode->i_sb != sb)
549 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700550 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 __wait_on_freeing_inode(inode);
552 goto repeat;
553 }
554 break;
555 }
556 return node ? inode : NULL;
557}
558
David Chinner8290c352008-10-30 17:35:24 +1100559static unsigned long hash(struct super_block *sb, unsigned long hashval)
560{
561 unsigned long tmp;
562
563 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
564 L1_CACHE_BYTES;
565 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
566 return tmp & I_HASHMASK;
567}
568
569static inline void
570__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
571 struct inode *inode)
572{
573 inodes_stat.nr_inodes++;
574 list_add(&inode->i_list, &inode_in_use);
575 list_add(&inode->i_sb_list, &sb->s_inodes);
576 if (head)
577 hlist_add_head(&inode->i_hash, head);
578}
579
580/**
581 * inode_add_to_lists - add a new inode to relevant lists
Randy Dunlap0bc02f32009-01-06 14:41:13 -0800582 * @sb: superblock inode belongs to
583 * @inode: inode to mark in use
David Chinner8290c352008-10-30 17:35:24 +1100584 *
585 * When an inode is allocated it needs to be accounted for, added to the in use
586 * list, the owning superblock and the inode hash. This needs to be done under
587 * the inode_lock, so export a function to do this rather than the inode lock
588 * itself. We calculate the hash list to add to here so it is all internal
589 * which requires the caller to have already set up the inode number in the
590 * inode to add.
591 */
592void inode_add_to_lists(struct super_block *sb, struct inode *inode)
593{
594 struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
595
596 spin_lock(&inode_lock);
597 __inode_add_to_lists(sb, head, inode);
598 spin_unlock(&inode_lock);
599}
600EXPORT_SYMBOL_GPL(inode_add_to_lists);
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602/**
603 * new_inode - obtain an inode
604 * @sb: superblock
605 *
Mel Gorman769848c2007-07-17 04:03:05 -0700606 * Allocates a new inode for given superblock. The default gfp_mask
Hugh Dickins3c1d4372009-01-06 14:39:23 -0800607 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
Mel Gorman769848c2007-07-17 04:03:05 -0700608 * If HIGHMEM pages are unsuitable or it is known that pages allocated
609 * for the page cache are not reclaimable or migratable,
610 * mapping_set_gfp_mask() must be called with suitable flags on the
611 * newly created inode's mapping
612 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 */
614struct inode *new_inode(struct super_block *sb)
615{
Jeff Layton866b04f2007-05-08 00:32:29 -0700616 /*
617 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
618 * error if st_ino won't fit in target struct field. Use 32bit counter
619 * here to attempt to avoid that.
620 */
621 static unsigned int last_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 struct inode * inode;
623
624 spin_lock_prefetch(&inode_lock);
625
626 inode = alloc_inode(sb);
627 if (inode) {
628 spin_lock(&inode_lock);
David Chinner8290c352008-10-30 17:35:24 +1100629 __inode_add_to_lists(sb, NULL, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 inode->i_ino = ++last_ino;
631 inode->i_state = 0;
632 spin_unlock(&inode_lock);
633 }
634 return inode;
635}
636
637EXPORT_SYMBOL(new_inode);
638
639void unlock_new_inode(struct inode *inode)
640{
Peter Zijlstra14358e62007-10-14 01:38:33 +0200641#ifdef CONFIG_DEBUG_LOCK_ALLOC
Peter Zijlstra1e89a5e2007-10-16 06:47:54 +0200642 if (inode->i_mode & S_IFDIR) {
643 struct file_system_type *type = inode->i_sb->s_type;
644
645 /*
646 * ensure nobody is actually holding i_mutex
647 */
648 mutex_destroy(&inode->i_mutex);
649 mutex_init(&inode->i_mutex);
Peter Zijlstra14358e62007-10-14 01:38:33 +0200650 lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key);
Peter Zijlstra1e89a5e2007-10-16 06:47:54 +0200651 }
Peter Zijlstra14358e62007-10-14 01:38:33 +0200652#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 /*
654 * This is special! We do not need the spinlock
655 * when clearing I_LOCK, because we're guaranteed
656 * that nobody else tries to do anything about the
657 * state of the inode when it is locked, as we
658 * just created it (so there can be no old holders
659 * that haven't tested I_LOCK).
660 */
Nick Piggin7ef0d732009-03-12 14:31:38 -0700661 WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 inode->i_state &= ~(I_LOCK|I_NEW);
663 wake_up_inode(inode);
664}
665
666EXPORT_SYMBOL(unlock_new_inode);
667
668/*
669 * This is called without the inode lock held.. Be careful.
670 *
671 * We no longer cache the sb_flags in i_flags - see fs.h
672 * -- rmk@arm.uk.linux.org
673 */
674static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data)
675{
676 struct inode * inode;
677
678 inode = alloc_inode(sb);
679 if (inode) {
680 struct inode * old;
681
682 spin_lock(&inode_lock);
683 /* We released the lock, so.. */
684 old = find_inode(sb, head, test, data);
685 if (!old) {
686 if (set(inode, data))
687 goto set_failed;
688
David Chinner8290c352008-10-30 17:35:24 +1100689 __inode_add_to_lists(sb, head, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 inode->i_state = I_LOCK|I_NEW;
691 spin_unlock(&inode_lock);
692
693 /* Return the locked inode with I_NEW set, the
694 * caller is responsible for filling in the contents
695 */
696 return inode;
697 }
698
699 /*
700 * Uhhuh, somebody else created the same inode under
701 * us. Use the old inode instead of the one we just
702 * allocated.
703 */
704 __iget(old);
705 spin_unlock(&inode_lock);
706 destroy_inode(inode);
707 inode = old;
708 wait_on_inode(inode);
709 }
710 return inode;
711
712set_failed:
713 spin_unlock(&inode_lock);
714 destroy_inode(inode);
715 return NULL;
716}
717
718/*
719 * get_new_inode_fast is the fast path version of get_new_inode, see the
720 * comment at iget_locked for details.
721 */
722static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
723{
724 struct inode * inode;
725
726 inode = alloc_inode(sb);
727 if (inode) {
728 struct inode * old;
729
730 spin_lock(&inode_lock);
731 /* We released the lock, so.. */
732 old = find_inode_fast(sb, head, ino);
733 if (!old) {
734 inode->i_ino = ino;
David Chinner8290c352008-10-30 17:35:24 +1100735 __inode_add_to_lists(sb, head, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 inode->i_state = I_LOCK|I_NEW;
737 spin_unlock(&inode_lock);
738
739 /* Return the locked inode with I_NEW set, the
740 * caller is responsible for filling in the contents
741 */
742 return inode;
743 }
744
745 /*
746 * Uhhuh, somebody else created the same inode under
747 * us. Use the old inode instead of the one we just
748 * allocated.
749 */
750 __iget(old);
751 spin_unlock(&inode_lock);
752 destroy_inode(inode);
753 inode = old;
754 wait_on_inode(inode);
755 }
756 return inode;
757}
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759/**
760 * iunique - get a unique inode number
761 * @sb: superblock
762 * @max_reserved: highest reserved inode number
763 *
764 * Obtain an inode number that is unique on the system for a given
765 * superblock. This is used by file systems that have no natural
766 * permanent inode numbering system. An inode number is returned that
767 * is higher than the reserved limit but unique.
768 *
769 * BUGS:
770 * With a large number of inodes live on the file system this function
771 * currently becomes quite slow.
772 */
773ino_t iunique(struct super_block *sb, ino_t max_reserved)
774{
Jeff Layton866b04f2007-05-08 00:32:29 -0700775 /*
776 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
777 * error if st_ino won't fit in target struct field. Use 32bit counter
778 * here to attempt to avoid that.
779 */
780 static unsigned int counter;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 struct inode *inode;
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700782 struct hlist_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 ino_t res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700785 spin_lock(&inode_lock);
786 do {
787 if (counter <= max_reserved)
788 counter = max_reserved + 1;
789 res = counter++;
790 head = inode_hashtable + hash(sb, res);
791 inode = find_inode_fast(sb, head, res);
792 } while (inode != NULL);
793 spin_unlock(&inode_lock);
794
795 return res;
796}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797EXPORT_SYMBOL(iunique);
798
799struct inode *igrab(struct inode *inode)
800{
801 spin_lock(&inode_lock);
Jan Blunck4a3b0a42007-02-10 01:44:59 -0800802 if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 __iget(inode);
804 else
805 /*
806 * Handle the case where s_op->clear_inode is not been
807 * called yet, and somebody is calling igrab
808 * while the inode is getting freed.
809 */
810 inode = NULL;
811 spin_unlock(&inode_lock);
812 return inode;
813}
814
815EXPORT_SYMBOL(igrab);
816
817/**
818 * ifind - internal function, you want ilookup5() or iget5().
819 * @sb: super block of file system to search
820 * @head: the head of the list to search
821 * @test: callback used for comparisons between inodes
822 * @data: opaque data pointer to pass to @test
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700823 * @wait: if true wait for the inode to be unlocked, if false do not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 *
825 * ifind() searches for the inode specified by @data in the inode
826 * cache. This is a generalized version of ifind_fast() for file systems where
827 * the inode number is not sufficient for unique identification of an inode.
828 *
829 * If the inode is in the cache, the inode is returned with an incremented
830 * reference count.
831 *
832 * Otherwise NULL is returned.
833 *
834 * Note, @test is called with the inode_lock held, so can't sleep.
835 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800836static struct inode *ifind(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 struct hlist_head *head, int (*test)(struct inode *, void *),
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700838 void *data, const int wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839{
840 struct inode *inode;
841
842 spin_lock(&inode_lock);
843 inode = find_inode(sb, head, test, data);
844 if (inode) {
845 __iget(inode);
846 spin_unlock(&inode_lock);
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700847 if (likely(wait))
848 wait_on_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 return inode;
850 }
851 spin_unlock(&inode_lock);
852 return NULL;
853}
854
855/**
856 * ifind_fast - internal function, you want ilookup() or iget().
857 * @sb: super block of file system to search
858 * @head: head of the list to search
859 * @ino: inode number to search for
860 *
861 * ifind_fast() searches for the inode @ino in the inode cache. This is for
862 * file systems where the inode number is sufficient for unique identification
863 * of an inode.
864 *
865 * If the inode is in the cache, the inode is returned with an incremented
866 * reference count.
867 *
868 * Otherwise NULL is returned.
869 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800870static struct inode *ifind_fast(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 struct hlist_head *head, unsigned long ino)
872{
873 struct inode *inode;
874
875 spin_lock(&inode_lock);
876 inode = find_inode_fast(sb, head, ino);
877 if (inode) {
878 __iget(inode);
879 spin_unlock(&inode_lock);
880 wait_on_inode(inode);
881 return inode;
882 }
883 spin_unlock(&inode_lock);
884 return NULL;
885}
886
887/**
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700888 * ilookup5_nowait - search for an inode in the inode cache
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 * @sb: super block of file system to search
890 * @hashval: hash value (usually inode number) to search for
891 * @test: callback used for comparisons between inodes
892 * @data: opaque data pointer to pass to @test
893 *
894 * ilookup5() uses ifind() to search for the inode specified by @hashval and
895 * @data in the inode cache. This is a generalized version of ilookup() for
896 * file systems where the inode number is not sufficient for unique
897 * identification of an inode.
898 *
899 * If the inode is in the cache, the inode is returned with an incremented
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700900 * reference count. Note, the inode lock is not waited upon so you have to be
901 * very careful what you do with the returned inode. You probably should be
902 * using ilookup5() instead.
903 *
904 * Otherwise NULL is returned.
905 *
906 * Note, @test is called with the inode_lock held, so can't sleep.
907 */
908struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
909 int (*test)(struct inode *, void *), void *data)
910{
911 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
912
913 return ifind(sb, head, test, data, 0);
914}
915
916EXPORT_SYMBOL(ilookup5_nowait);
917
918/**
919 * ilookup5 - search for an inode in the inode cache
920 * @sb: super block of file system to search
921 * @hashval: hash value (usually inode number) to search for
922 * @test: callback used for comparisons between inodes
923 * @data: opaque data pointer to pass to @test
924 *
925 * ilookup5() uses ifind() to search for the inode specified by @hashval and
926 * @data in the inode cache. This is a generalized version of ilookup() for
927 * file systems where the inode number is not sufficient for unique
928 * identification of an inode.
929 *
930 * If the inode is in the cache, the inode lock is waited upon and the inode is
931 * returned with an incremented reference count.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 *
933 * Otherwise NULL is returned.
934 *
935 * Note, @test is called with the inode_lock held, so can't sleep.
936 */
937struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
938 int (*test)(struct inode *, void *), void *data)
939{
940 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
941
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700942 return ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943}
944
945EXPORT_SYMBOL(ilookup5);
946
947/**
948 * ilookup - search for an inode in the inode cache
949 * @sb: super block of file system to search
950 * @ino: inode number to search for
951 *
952 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
953 * This is for file systems where the inode number is sufficient for unique
954 * identification of an inode.
955 *
956 * If the inode is in the cache, the inode is returned with an incremented
957 * reference count.
958 *
959 * Otherwise NULL is returned.
960 */
961struct inode *ilookup(struct super_block *sb, unsigned long ino)
962{
963 struct hlist_head *head = inode_hashtable + hash(sb, ino);
964
965 return ifind_fast(sb, head, ino);
966}
967
968EXPORT_SYMBOL(ilookup);
969
970/**
971 * iget5_locked - obtain an inode from a mounted file system
972 * @sb: super block of file system
973 * @hashval: hash value (usually inode number) to get
974 * @test: callback used for comparisons between inodes
975 * @set: callback used to initialize a new struct inode
976 * @data: opaque data pointer to pass to @test and @set
977 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 * iget5_locked() uses ifind() to search for the inode specified by @hashval
979 * and @data in the inode cache and if present it is returned with an increased
980 * reference count. This is a generalized version of iget_locked() for file
981 * systems where the inode number is not sufficient for unique identification
982 * of an inode.
983 *
984 * If the inode is not in cache, get_new_inode() is called to allocate a new
985 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
986 * file system gets to fill it in before unlocking it via unlock_new_inode().
987 *
988 * Note both @test and @set are called with the inode_lock held, so can't sleep.
989 */
990struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
991 int (*test)(struct inode *, void *),
992 int (*set)(struct inode *, void *), void *data)
993{
994 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
995 struct inode *inode;
996
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700997 inode = ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 if (inode)
999 return inode;
1000 /*
1001 * get_new_inode() will do the right thing, re-trying the search
1002 * in case it had to block at any point.
1003 */
1004 return get_new_inode(sb, head, test, set, data);
1005}
1006
1007EXPORT_SYMBOL(iget5_locked);
1008
1009/**
1010 * iget_locked - obtain an inode from a mounted file system
1011 * @sb: super block of file system
1012 * @ino: inode number to get
1013 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
1015 * the inode cache and if present it is returned with an increased reference
1016 * count. This is for file systems where the inode number is sufficient for
1017 * unique identification of an inode.
1018 *
1019 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
1020 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
1021 * The file system gets to fill it in before unlocking it via
1022 * unlock_new_inode().
1023 */
1024struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1025{
1026 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1027 struct inode *inode;
1028
1029 inode = ifind_fast(sb, head, ino);
1030 if (inode)
1031 return inode;
1032 /*
1033 * get_new_inode_fast() will do the right thing, re-trying the search
1034 * in case it had to block at any point.
1035 */
1036 return get_new_inode_fast(sb, head, ino);
1037}
1038
1039EXPORT_SYMBOL(iget_locked);
1040
Al Viro261bca82008-12-30 01:48:21 -05001041int insert_inode_locked(struct inode *inode)
1042{
1043 struct super_block *sb = inode->i_sb;
1044 ino_t ino = inode->i_ino;
1045 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1046 struct inode *old;
1047
1048 inode->i_state |= I_LOCK|I_NEW;
1049 while (1) {
1050 spin_lock(&inode_lock);
1051 old = find_inode_fast(sb, head, ino);
1052 if (likely(!old)) {
1053 hlist_add_head(&inode->i_hash, head);
1054 spin_unlock(&inode_lock);
1055 return 0;
1056 }
1057 __iget(old);
1058 spin_unlock(&inode_lock);
1059 wait_on_inode(old);
1060 if (unlikely(!hlist_unhashed(&old->i_hash))) {
1061 iput(old);
1062 return -EBUSY;
1063 }
1064 iput(old);
1065 }
1066}
1067
1068EXPORT_SYMBOL(insert_inode_locked);
1069
1070int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1071 int (*test)(struct inode *, void *), void *data)
1072{
1073 struct super_block *sb = inode->i_sb;
1074 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1075 struct inode *old;
1076
1077 inode->i_state |= I_LOCK|I_NEW;
1078
1079 while (1) {
1080 spin_lock(&inode_lock);
1081 old = find_inode(sb, head, test, data);
1082 if (likely(!old)) {
1083 hlist_add_head(&inode->i_hash, head);
1084 spin_unlock(&inode_lock);
1085 return 0;
1086 }
1087 __iget(old);
1088 spin_unlock(&inode_lock);
1089 wait_on_inode(old);
1090 if (unlikely(!hlist_unhashed(&old->i_hash))) {
1091 iput(old);
1092 return -EBUSY;
1093 }
1094 iput(old);
1095 }
1096}
1097
1098EXPORT_SYMBOL(insert_inode_locked4);
1099
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100/**
1101 * __insert_inode_hash - hash an inode
1102 * @inode: unhashed inode
1103 * @hashval: unsigned long value used to locate this object in the
1104 * inode_hashtable.
1105 *
1106 * Add an inode to the inode hash for this superblock.
1107 */
1108void __insert_inode_hash(struct inode *inode, unsigned long hashval)
1109{
1110 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
1111 spin_lock(&inode_lock);
1112 hlist_add_head(&inode->i_hash, head);
1113 spin_unlock(&inode_lock);
1114}
1115
1116EXPORT_SYMBOL(__insert_inode_hash);
1117
1118/**
1119 * remove_inode_hash - remove an inode from the hash
1120 * @inode: inode to unhash
1121 *
1122 * Remove an inode from the superblock.
1123 */
1124void remove_inode_hash(struct inode *inode)
1125{
1126 spin_lock(&inode_lock);
1127 hlist_del_init(&inode->i_hash);
1128 spin_unlock(&inode_lock);
1129}
1130
1131EXPORT_SYMBOL(remove_inode_hash);
1132
1133/*
1134 * Tell the filesystem that this inode is no longer of any interest and should
1135 * be completely destroyed.
1136 *
1137 * We leave the inode in the inode hash table until *after* the filesystem's
1138 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1139 * instigate) will always find up-to-date information either in the hash or on
1140 * disk.
1141 *
1142 * I_FREEING is set so that no-one will take a new reference to the inode while
1143 * it is being deleted.
1144 */
Arjan van de Venb32714b2009-01-09 07:04:15 -08001145void generic_delete_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001147 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148
Arjan van de Venb32714b2009-01-09 07:04:15 -08001149 list_del_init(&inode->i_list);
1150 list_del_init(&inode->i_sb_list);
Nick Piggin7ef0d732009-03-12 14:31:38 -07001151 WARN_ON(inode->i_state & I_NEW);
Arjan van de Venb32714b2009-01-09 07:04:15 -08001152 inode->i_state |= I_FREEING;
1153 inodes_stat.nr_inodes--;
1154 spin_unlock(&inode_lock);
1155
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 security_inode_delete(inode);
1157
1158 if (op->delete_inode) {
1159 void (*delete)(struct inode *) = op->delete_inode;
1160 if (!is_bad_inode(inode))
1161 DQUOT_INIT(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001162 /* Filesystems implementing their own
1163 * s_op->delete_inode are required to call
1164 * truncate_inode_pages and clear_inode()
1165 * internally */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 delete(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001167 } else {
1168 truncate_inode_pages(&inode->i_data, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 clear_inode(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001170 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 spin_lock(&inode_lock);
1172 hlist_del_init(&inode->i_hash);
1173 spin_unlock(&inode_lock);
1174 wake_up_inode(inode);
Eric Sesterhennb7542f82006-04-02 13:38:18 +02001175 BUG_ON(inode->i_state != I_CLEAR);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 destroy_inode(inode);
1177}
1178
1179EXPORT_SYMBOL(generic_delete_inode);
1180
1181static void generic_forget_inode(struct inode *inode)
1182{
1183 struct super_block *sb = inode->i_sb;
1184
1185 if (!hlist_unhashed(&inode->i_hash)) {
Joern Engel1c0eeaf2007-10-16 23:30:44 -07001186 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 list_move(&inode->i_list, &inode_unused);
1188 inodes_stat.nr_unused++;
Christoph Hellwigacb0c852007-05-08 00:25:52 -07001189 if (sb->s_flags & MS_ACTIVE) {
Alexander Viro991114c2005-06-23 00:09:01 -07001190 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 return;
Alexander Viro991114c2005-06-23 00:09:01 -07001192 }
Nick Piggin7ef0d732009-03-12 14:31:38 -07001193 WARN_ON(inode->i_state & I_NEW);
Alexander Viro991114c2005-06-23 00:09:01 -07001194 inode->i_state |= I_WILL_FREE;
1195 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 write_inode_now(inode, 1);
1197 spin_lock(&inode_lock);
Nick Piggin7ef0d732009-03-12 14:31:38 -07001198 WARN_ON(inode->i_state & I_NEW);
Alexander Viro991114c2005-06-23 00:09:01 -07001199 inode->i_state &= ~I_WILL_FREE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 inodes_stat.nr_unused--;
1201 hlist_del_init(&inode->i_hash);
1202 }
1203 list_del_init(&inode->i_list);
1204 list_del_init(&inode->i_sb_list);
Nick Piggin7ef0d732009-03-12 14:31:38 -07001205 WARN_ON(inode->i_state & I_NEW);
Alexander Viro991114c2005-06-23 00:09:01 -07001206 inode->i_state |= I_FREEING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 inodes_stat.nr_inodes--;
1208 spin_unlock(&inode_lock);
1209 if (inode->i_data.nrpages)
1210 truncate_inode_pages(&inode->i_data, 0);
1211 clear_inode(inode);
Andrea Arcangeli7f04c262005-10-30 15:03:05 -08001212 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 destroy_inode(inode);
1214}
1215
1216/*
1217 * Normal UNIX filesystem behaviour: delete the
1218 * inode when the usage count drops to zero, and
1219 * i_nlink is zero.
1220 */
Mark Fashehcb2c0232005-07-07 17:56:03 -07001221void generic_drop_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222{
1223 if (!inode->i_nlink)
1224 generic_delete_inode(inode);
1225 else
1226 generic_forget_inode(inode);
1227}
1228
Mark Fashehcb2c0232005-07-07 17:56:03 -07001229EXPORT_SYMBOL_GPL(generic_drop_inode);
1230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231/*
1232 * Called when we're dropping the last reference
1233 * to an inode.
1234 *
1235 * Call the FS "drop()" function, defaulting to
1236 * the legacy UNIX filesystem behaviour..
1237 *
1238 * NOTE! NOTE! NOTE! We're called with the inode lock
1239 * held, and the drop function is supposed to release
1240 * the lock!
1241 */
1242static inline void iput_final(struct inode *inode)
1243{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001244 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 void (*drop)(struct inode *) = generic_drop_inode;
1246
1247 if (op && op->drop_inode)
1248 drop = op->drop_inode;
1249 drop(inode);
1250}
1251
1252/**
1253 * iput - put an inode
1254 * @inode: inode to put
1255 *
1256 * Puts an inode, dropping its usage count. If the inode use count hits
1257 * zero, the inode is then freed and may also be destroyed.
1258 *
1259 * Consequently, iput() can sleep.
1260 */
1261void iput(struct inode *inode)
1262{
1263 if (inode) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 BUG_ON(inode->i_state == I_CLEAR);
1265
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1267 iput_final(inode);
1268 }
1269}
1270
1271EXPORT_SYMBOL(iput);
1272
1273/**
1274 * bmap - find a block number in a file
1275 * @inode: inode of file
1276 * @block: block to find
1277 *
1278 * Returns the block number on the device holding the inode that
1279 * is the disk block number for the block of the file requested.
1280 * That is, asked for block 4 of inode 1 the function will return the
1281 * disk block relative to the disk start that holds that block of the
1282 * file.
1283 */
1284sector_t bmap(struct inode * inode, sector_t block)
1285{
1286 sector_t res = 0;
1287 if (inode->i_mapping->a_ops->bmap)
1288 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1289 return res;
1290}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291EXPORT_SYMBOL(bmap);
1292
1293/**
Christoph Hellwig869243a2006-01-09 20:52:03 -08001294 * touch_atime - update the access time
1295 * @mnt: mount the inode is accessed on
Martin Waitz7045f372006-02-01 03:06:57 -08001296 * @dentry: dentry accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 *
1298 * Update the accessed time on an inode and mark it for writeback.
1299 * This function automatically handles read only file systems and media,
1300 * as well as the "noatime" flag and inode specific "noatime" markers.
1301 */
Christoph Hellwig869243a2006-01-09 20:52:03 -08001302void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303{
Christoph Hellwig869243a2006-01-09 20:52:03 -08001304 struct inode *inode = dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305 struct timespec now;
1306
Dave Hansencdb70f32008-02-15 14:37:41 -08001307 if (mnt_want_write(mnt))
1308 return;
Andrew Mortonb2276132006-12-13 00:34:33 -08001309 if (inode->i_flags & S_NOATIME)
Dave Hansencdb70f32008-02-15 14:37:41 -08001310 goto out;
Eric Dumazet37756ce2007-02-10 01:44:49 -08001311 if (IS_NOATIME(inode))
Dave Hansencdb70f32008-02-15 14:37:41 -08001312 goto out;
Andrew Mortonb2276132006-12-13 00:34:33 -08001313 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
Dave Hansencdb70f32008-02-15 14:37:41 -08001314 goto out;
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001315
Dave Hansencdb70f32008-02-15 14:37:41 -08001316 if (mnt->mnt_flags & MNT_NOATIME)
1317 goto out;
1318 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1319 goto out;
1320 if (mnt->mnt_flags & MNT_RELATIME) {
1321 /*
1322 * With relative atime, only update atime if the previous
1323 * atime is earlier than either the ctime or mtime.
1324 */
1325 if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 &&
1326 timespec_compare(&inode->i_ctime, &inode->i_atime) < 0)
1327 goto out;
Andrew Mortonb2276132006-12-13 00:34:33 -08001328 }
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001329
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 now = current_fs_time(inode->i_sb);
Valerie Henson47ae32d2006-12-13 00:34:34 -08001331 if (timespec_equal(&inode->i_atime, &now))
Dave Hansencdb70f32008-02-15 14:37:41 -08001332 goto out;
Valerie Henson47ae32d2006-12-13 00:34:34 -08001333
1334 inode->i_atime = now;
1335 mark_inode_dirty_sync(inode);
Dave Hansencdb70f32008-02-15 14:37:41 -08001336out:
1337 mnt_drop_write(mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338}
Christoph Hellwig869243a2006-01-09 20:52:03 -08001339EXPORT_SYMBOL(touch_atime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340
1341/**
Christoph Hellwig870f4812006-01-09 20:52:01 -08001342 * file_update_time - update mtime and ctime time
1343 * @file: file accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 *
Christoph Hellwig870f4812006-01-09 20:52:01 -08001345 * Update the mtime and ctime members of an inode and mark the inode
1346 * for writeback. Note that this function is meant exclusively for
1347 * usage in the file write path of filesystems, and filesystems may
1348 * choose to explicitly ignore update via this function with the
1349 * S_NOCTIME inode flag, e.g. for network filesystem where these
1350 * timestamps are handled by the server.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 */
1352
Christoph Hellwig870f4812006-01-09 20:52:01 -08001353void file_update_time(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001355 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 struct timespec now;
1357 int sync_it = 0;
Dave Hansen20ddee22008-02-15 14:37:43 -08001358 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359
1360 if (IS_NOCMTIME(inode))
1361 return;
Dave Hansen20ddee22008-02-15 14:37:43 -08001362
1363 err = mnt_want_write(file->f_path.mnt);
1364 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 return;
1366
1367 now = current_fs_time(inode->i_sb);
Andreas Mohred97bd32006-10-02 02:17:17 -07001368 if (!timespec_equal(&inode->i_mtime, &now)) {
1369 inode->i_mtime = now;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001371 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
Andreas Mohred97bd32006-10-02 02:17:17 -07001373 if (!timespec_equal(&inode->i_ctime, &now)) {
1374 inode->i_ctime = now;
Christoph Hellwig870f4812006-01-09 20:52:01 -08001375 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001376 }
Christoph Hellwig870f4812006-01-09 20:52:01 -08001377
Jean Noel Cordenner7a224222008-01-28 23:58:27 -05001378 if (IS_I_VERSION(inode)) {
1379 inode_inc_iversion(inode);
1380 sync_it = 1;
1381 }
1382
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 if (sync_it)
1384 mark_inode_dirty_sync(inode);
Dave Hansen20ddee22008-02-15 14:37:43 -08001385 mnt_drop_write(file->f_path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386}
1387
Christoph Hellwig870f4812006-01-09 20:52:01 -08001388EXPORT_SYMBOL(file_update_time);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389
1390int inode_needs_sync(struct inode *inode)
1391{
1392 if (IS_SYNC(inode))
1393 return 1;
1394 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1395 return 1;
1396 return 0;
1397}
1398
1399EXPORT_SYMBOL(inode_needs_sync);
1400
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401int inode_wait(void *word)
1402{
1403 schedule();
1404 return 0;
1405}
Stephen Rothwelld44dab82008-11-10 17:06:05 +11001406EXPORT_SYMBOL(inode_wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407
1408/*
Miklos Szeredi168a9fd2005-07-12 13:58:10 -07001409 * If we try to find an inode in the inode hash while it is being
1410 * deleted, we have to wait until the filesystem completes its
1411 * deletion before reporting that it isn't found. This function waits
1412 * until the deletion _might_ have completed. Callers are responsible
1413 * to recheck inode state.
1414 *
1415 * It doesn't matter if I_LOCK is not set initially, a call to
1416 * wake_up_inode() after removing from the hash list will DTRT.
1417 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 * This is called with inode_lock held.
1419 */
1420static void __wait_on_freeing_inode(struct inode *inode)
1421{
1422 wait_queue_head_t *wq;
1423 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 wq = bit_waitqueue(&inode->i_state, __I_LOCK);
1425 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1426 spin_unlock(&inode_lock);
1427 schedule();
1428 finish_wait(wq, &wait.wait);
1429 spin_lock(&inode_lock);
1430}
1431
Mark Fasheh62752ee2006-10-17 10:31:38 +02001432/*
1433 * We rarely want to lock two inodes that do not have a parent/child
1434 * relationship (such as directory, child inode) simultaneously. The
1435 * vast majority of file systems should be able to get along fine
1436 * without this. Do not use these functions except as a last resort.
1437 */
1438void inode_double_lock(struct inode *inode1, struct inode *inode2)
1439{
1440 if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
1441 if (inode1)
1442 mutex_lock(&inode1->i_mutex);
1443 else if (inode2)
1444 mutex_lock(&inode2->i_mutex);
1445 return;
1446 }
1447
1448 if (inode1 < inode2) {
1449 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1450 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1451 } else {
1452 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1453 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1454 }
1455}
1456EXPORT_SYMBOL(inode_double_lock);
1457
1458void inode_double_unlock(struct inode *inode1, struct inode *inode2)
1459{
1460 if (inode1)
1461 mutex_unlock(&inode1->i_mutex);
1462
1463 if (inode2 && inode2 != inode1)
1464 mutex_unlock(&inode2->i_mutex);
1465}
1466EXPORT_SYMBOL(inode_double_unlock);
1467
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468static __initdata unsigned long ihash_entries;
1469static int __init set_ihash_entries(char *str)
1470{
1471 if (!str)
1472 return 0;
1473 ihash_entries = simple_strtoul(str, &str, 0);
1474 return 1;
1475}
1476__setup("ihash_entries=", set_ihash_entries);
1477
1478/*
1479 * Initialize the waitqueues and inode hash table.
1480 */
1481void __init inode_init_early(void)
1482{
1483 int loop;
1484
1485 /* If hashes are distributed across NUMA nodes, defer
1486 * hash allocation until vmalloc space is available.
1487 */
1488 if (hashdist)
1489 return;
1490
1491 inode_hashtable =
1492 alloc_large_system_hash("Inode-cache",
1493 sizeof(struct hlist_head),
1494 ihash_entries,
1495 14,
1496 HASH_EARLY,
1497 &i_hash_shift,
1498 &i_hash_mask,
1499 0);
1500
1501 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1502 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1503}
1504
Denis Cheng74bf17c2007-10-16 23:26:30 -07001505void __init inode_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506{
1507 int loop;
1508
1509 /* inode slab cache */
Paul Jacksonb0196002006-03-24 03:16:09 -08001510 inode_cachep = kmem_cache_create("inode_cache",
1511 sizeof(struct inode),
1512 0,
1513 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1514 SLAB_MEM_SPREAD),
Paul Mundt20c2df82007-07-20 10:11:58 +09001515 init_once);
Rusty Russell8e1f9362007-07-17 04:03:17 -07001516 register_shrinker(&icache_shrinker);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517
1518 /* Hash may have been set up in inode_init_early */
1519 if (!hashdist)
1520 return;
1521
1522 inode_hashtable =
1523 alloc_large_system_hash("Inode-cache",
1524 sizeof(struct hlist_head),
1525 ihash_entries,
1526 14,
1527 0,
1528 &i_hash_shift,
1529 &i_hash_mask,
1530 0);
1531
1532 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1533 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1534}
1535
1536void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1537{
1538 inode->i_mode = mode;
1539 if (S_ISCHR(mode)) {
1540 inode->i_fop = &def_chr_fops;
1541 inode->i_rdev = rdev;
1542 } else if (S_ISBLK(mode)) {
1543 inode->i_fop = &def_blk_fops;
1544 inode->i_rdev = rdev;
1545 } else if (S_ISFIFO(mode))
1546 inode->i_fop = &def_fifo_fops;
1547 else if (S_ISSOCK(mode))
1548 inode->i_fop = &bad_sock_fops;
1549 else
1550 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
1551 mode);
1552}
1553EXPORT_SYMBOL(init_special_inode);