blob: 320e088d0b28ba57648586314a23d9f011b61a72 [file] [log] [blame]
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26/*
27 * This is needed for the following functions:
28 * - inode_has_buffers
29 * - invalidate_inode_buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 * - invalidate_bdev
31 *
32 * FIXME: remove all knowledge of the buffer layer from this file
33 */
34#include <linux/buffer_head.h>
35
36/*
37 * New inode.c implementation.
38 *
39 * This implementation has the basic premise of trying
40 * to be extremely low-overhead and SMP-safe, yet be
41 * simple enough to be "obviously correct".
42 *
43 * Famous last words.
44 */
45
46/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
47
48/* #define INODE_PARANOIA 1 */
49/* #define INODE_DEBUG 1 */
50
51/*
52 * Inode lookup is no longer as critical as it used to be:
53 * most of the lookups are going to be through the dcache.
54 */
55#define I_HASHBITS i_hash_shift
56#define I_HASHMASK i_hash_mask
57
Eric Dumazetfa3536c2006-03-26 01:37:24 -080058static unsigned int i_hash_mask __read_mostly;
59static unsigned int i_hash_shift __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/*
62 * Each inode can be on two separate lists. One is
63 * the hash list of the inode, used for lookups. The
64 * other linked list is the "type" list:
65 * "in_use" - valid inode, i_count > 0, i_nlink > 0
66 * "dirty" - as "in_use" but also dirty
67 * "unused" - valid inode, i_count = 0
68 *
69 * A "dirty" list is maintained for each super block,
70 * allowing for low-overhead inode sync() operations.
71 */
72
73LIST_HEAD(inode_in_use);
74LIST_HEAD(inode_unused);
Eric Dumazetfa3536c2006-03-26 01:37:24 -080075static struct hlist_head *inode_hashtable __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
77/*
78 * A simple spinlock to protect the list manipulations.
79 *
80 * NOTE! You also have to own the lock if you change
81 * the i_state of an inode while it is in use..
82 */
83DEFINE_SPINLOCK(inode_lock);
84
85/*
Ingo Molnarf24075b2006-03-23 03:00:34 -080086 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 * icache shrinking path, and the umount path. Without this exclusion,
88 * by the time prune_icache calls iput for the inode whose pages it has
89 * been invalidating, or by the time it calls clear_inode & destroy_inode
90 * from its final dispose_list, the struct super_block they refer to
91 * (for inode->i_sb->s_op) may already have been freed and reused.
92 */
Adrian Bunkbdfc3262006-03-25 03:06:56 -080093static DEFINE_MUTEX(iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95/*
96 * Statistics gathering..
97 */
98struct inodes_stat_t inodes_stat;
99
Christoph Lametere18b8902006-12-06 20:33:20 -0800100static struct kmem_cache * inode_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
102static struct inode *alloc_inode(struct super_block *sb)
103{
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700104 static const struct address_space_operations empty_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 static struct inode_operations empty_iops;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800106 static const struct file_operations empty_fops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 struct inode *inode;
108
109 if (sb->s_op->alloc_inode)
110 inode = sb->s_op->alloc_inode(sb);
111 else
Christoph Lametere94b1762006-12-06 20:33:17 -0800112 inode = (struct inode *) kmem_cache_alloc(inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 if (inode) {
115 struct address_space * const mapping = &inode->i_data;
116
117 inode->i_sb = sb;
118 inode->i_blkbits = sb->s_blocksize_bits;
119 inode->i_flags = 0;
120 atomic_set(&inode->i_count, 1);
121 inode->i_op = &empty_iops;
122 inode->i_fop = &empty_fops;
123 inode->i_nlink = 1;
124 atomic_set(&inode->i_writecount, 0);
125 inode->i_size = 0;
126 inode->i_blocks = 0;
127 inode->i_bytes = 0;
128 inode->i_generation = 0;
129#ifdef CONFIG_QUOTA
130 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
131#endif
132 inode->i_pipe = NULL;
133 inode->i_bdev = NULL;
134 inode->i_cdev = NULL;
135 inode->i_rdev = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 inode->dirtied_when = 0;
137 if (security_inode_alloc(inode)) {
138 if (inode->i_sb->s_op->destroy_inode)
139 inode->i_sb->s_op->destroy_inode(inode);
140 else
141 kmem_cache_free(inode_cachep, (inode));
142 return NULL;
143 }
144
145 mapping->a_ops = &empty_aops;
146 mapping->host = inode;
147 mapping->flags = 0;
Mel Gorman769848c2007-07-17 04:03:05 -0700148 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 mapping->assoc_mapping = NULL;
150 mapping->backing_dev_info = &default_backing_dev_info;
151
152 /*
153 * If the block_device provides a backing_dev_info for client
154 * inodes then use that. Otherwise the inode share the bdev's
155 * backing_dev_info.
156 */
157 if (sb->s_bdev) {
158 struct backing_dev_info *bdi;
159
160 bdi = sb->s_bdev->bd_inode_backing_dev_info;
161 if (!bdi)
162 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
163 mapping->backing_dev_info = bdi;
164 }
Al Viroe6c6e642006-10-10 22:48:47 +0100165 inode->i_private = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 inode->i_mapping = mapping;
167 }
168 return inode;
169}
170
171void destroy_inode(struct inode *inode)
172{
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200173 BUG_ON(inode_has_buffers(inode));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 security_inode_free(inode);
175 if (inode->i_sb->s_op->destroy_inode)
176 inode->i_sb->s_op->destroy_inode(inode);
177 else
178 kmem_cache_free(inode_cachep, (inode));
179}
180
181
182/*
183 * These are initializations that only need to be done
184 * once, because the fields are idempotent across use
185 * of the inode, so let the slab aware of that.
186 */
187void inode_init_once(struct inode *inode)
188{
189 memset(inode, 0, sizeof(*inode));
190 INIT_HLIST_NODE(&inode->i_hash);
191 INIT_LIST_HEAD(&inode->i_dentry);
192 INIT_LIST_HEAD(&inode->i_devices);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800193 mutex_init(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 init_rwsem(&inode->i_alloc_sem);
195 INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
196 rwlock_init(&inode->i_data.tree_lock);
197 spin_lock_init(&inode->i_data.i_mmap_lock);
198 INIT_LIST_HEAD(&inode->i_data.private_list);
199 spin_lock_init(&inode->i_data.private_lock);
200 INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
201 INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
202 spin_lock_init(&inode->i_lock);
203 i_size_ordered_init(inode);
Robert Love0eeca282005-07-12 17:06:03 -0400204#ifdef CONFIG_INOTIFY
205 INIT_LIST_HEAD(&inode->inotify_watches);
Ingo Molnard4f9af92006-03-23 03:00:30 -0800206 mutex_init(&inode->inotify_mutex);
Robert Love0eeca282005-07-12 17:06:03 -0400207#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210EXPORT_SYMBOL(inode_init_once);
211
Christoph Lametere18b8902006-12-06 20:33:20 -0800212static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
214 struct inode * inode = (struct inode *) foo;
215
Christoph Lametera35afb82007-05-16 22:10:57 -0700216 inode_init_once(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217}
218
219/*
220 * inode_lock must be held
221 */
222void __iget(struct inode * inode)
223{
224 if (atomic_read(&inode->i_count)) {
225 atomic_inc(&inode->i_count);
226 return;
227 }
228 atomic_inc(&inode->i_count);
229 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
230 list_move(&inode->i_list, &inode_in_use);
231 inodes_stat.nr_unused--;
232}
233
234/**
235 * clear_inode - clear an inode
236 * @inode: inode to clear
237 *
238 * This is called by the filesystem to tell us
239 * that the inode is no longer useful. We just
240 * terminate it with extreme prejudice.
241 */
242void clear_inode(struct inode *inode)
243{
244 might_sleep();
245 invalidate_inode_buffers(inode);
246
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200247 BUG_ON(inode->i_data.nrpages);
248 BUG_ON(!(inode->i_state & I_FREEING));
249 BUG_ON(inode->i_state & I_CLEAR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 wait_on_inode(inode);
251 DQUOT_DROP(inode);
Christoph Hellwigacb0c852007-05-08 00:25:52 -0700252 if (inode->i_sb->s_op->clear_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 inode->i_sb->s_op->clear_inode(inode);
Theodore Ts'oeaf796e2006-09-27 01:50:48 -0700254 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 bd_forget(inode);
Theodore Ts'o577c4eb2006-09-27 01:50:49 -0700256 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 cd_forget(inode);
258 inode->i_state = I_CLEAR;
259}
260
261EXPORT_SYMBOL(clear_inode);
262
263/*
264 * dispose_list - dispose of the contents of a local list
265 * @head: the head of the list to free
266 *
267 * Dispose-list gets a local list with local inodes in it, so it doesn't
268 * need to worry about list corruption and SMP locks.
269 */
270static void dispose_list(struct list_head *head)
271{
272 int nr_disposed = 0;
273
274 while (!list_empty(head)) {
275 struct inode *inode;
276
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700277 inode = list_first_entry(head, struct inode, i_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 list_del(&inode->i_list);
279
280 if (inode->i_data.nrpages)
281 truncate_inode_pages(&inode->i_data, 0);
282 clear_inode(inode);
Artem B. Bityuckiy4120db42005-07-12 13:58:12 -0700283
284 spin_lock(&inode_lock);
285 hlist_del_init(&inode->i_hash);
286 list_del_init(&inode->i_sb_list);
287 spin_unlock(&inode_lock);
288
289 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 destroy_inode(inode);
291 nr_disposed++;
292 }
293 spin_lock(&inode_lock);
294 inodes_stat.nr_inodes -= nr_disposed;
295 spin_unlock(&inode_lock);
296}
297
298/*
299 * Invalidate all inodes for a device.
300 */
301static int invalidate_list(struct list_head *head, struct list_head *dispose)
302{
303 struct list_head *next;
304 int busy = 0, count = 0;
305
306 next = head->next;
307 for (;;) {
308 struct list_head * tmp = next;
309 struct inode * inode;
310
311 /*
312 * We can reschedule here without worrying about the list's
313 * consistency because the per-sb list of inodes must not
Ingo Molnarf24075b2006-03-23 03:00:34 -0800314 * change during umount anymore, and because iprune_mutex keeps
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 * shrink_icache_memory() away.
316 */
317 cond_resched_lock(&inode_lock);
318
319 next = next->next;
320 if (tmp == head)
321 break;
322 inode = list_entry(tmp, struct inode, i_sb_list);
323 invalidate_inode_buffers(inode);
324 if (!atomic_read(&inode->i_count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 list_move(&inode->i_list, dispose);
326 inode->i_state |= I_FREEING;
327 count++;
328 continue;
329 }
330 busy = 1;
331 }
332 /* only unused inodes may be cached with i_count zero */
333 inodes_stat.nr_unused -= count;
334 return busy;
335}
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337/**
338 * invalidate_inodes - discard the inodes on a device
339 * @sb: superblock
340 *
341 * Discard all of the inodes for a given superblock. If the discard
342 * fails because there are busy inodes then a non zero value is returned.
343 * If the discard is successful all the inodes have been discarded.
344 */
345int invalidate_inodes(struct super_block * sb)
346{
347 int busy;
348 LIST_HEAD(throw_away);
349
Ingo Molnarf24075b2006-03-23 03:00:34 -0800350 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 spin_lock(&inode_lock);
Robert Love0eeca282005-07-12 17:06:03 -0400352 inotify_unmount_inodes(&sb->s_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 busy = invalidate_list(&sb->s_inodes, &throw_away);
354 spin_unlock(&inode_lock);
355
356 dispose_list(&throw_away);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800357 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358
359 return busy;
360}
361
362EXPORT_SYMBOL(invalidate_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364static int can_unuse(struct inode *inode)
365{
366 if (inode->i_state)
367 return 0;
368 if (inode_has_buffers(inode))
369 return 0;
370 if (atomic_read(&inode->i_count))
371 return 0;
372 if (inode->i_data.nrpages)
373 return 0;
374 return 1;
375}
376
377/*
378 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
379 * a temporary list and then are freed outside inode_lock by dispose_list().
380 *
381 * Any inodes which are pinned purely because of attached pagecache have their
382 * pagecache removed. We expect the final iput() on that inode to add it to
383 * the front of the inode_unused list. So look for it there and if the
384 * inode is still freeable, proceed. The right inode is found 99.9% of the
385 * time in testing on a 4-way.
386 *
387 * If the inode has metadata buffers attached to mapping->private_list then
388 * try to remove them.
389 */
390static void prune_icache(int nr_to_scan)
391{
392 LIST_HEAD(freeable);
393 int nr_pruned = 0;
394 int nr_scanned;
395 unsigned long reap = 0;
396
Ingo Molnarf24075b2006-03-23 03:00:34 -0800397 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 spin_lock(&inode_lock);
399 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
400 struct inode *inode;
401
402 if (list_empty(&inode_unused))
403 break;
404
405 inode = list_entry(inode_unused.prev, struct inode, i_list);
406
407 if (inode->i_state || atomic_read(&inode->i_count)) {
408 list_move(&inode->i_list, &inode_unused);
409 continue;
410 }
411 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
412 __iget(inode);
413 spin_unlock(&inode_lock);
414 if (remove_inode_buffers(inode))
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800415 reap += invalidate_mapping_pages(&inode->i_data,
416 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 iput(inode);
418 spin_lock(&inode_lock);
419
420 if (inode != list_entry(inode_unused.next,
421 struct inode, i_list))
422 continue; /* wrong inode or list_empty */
423 if (!can_unuse(inode))
424 continue;
425 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 list_move(&inode->i_list, &freeable);
427 inode->i_state |= I_FREEING;
428 nr_pruned++;
429 }
430 inodes_stat.nr_unused -= nr_pruned;
Christoph Lameterf8891e52006-06-30 01:55:45 -0700431 if (current_is_kswapd())
432 __count_vm_events(KSWAPD_INODESTEAL, reap);
433 else
434 __count_vm_events(PGINODESTEAL, reap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 spin_unlock(&inode_lock);
436
437 dispose_list(&freeable);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800438 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439}
440
441/*
442 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
443 * "unused" means that no dentries are referring to the inodes: the files are
444 * not open and the dcache references to those inodes have already been
445 * reclaimed.
446 *
447 * This function is passed the number of inodes to scan, and it returns the
448 * total number of remaining possibly-reclaimable inodes.
449 */
Al Viro27496a82005-10-21 03:20:48 -0400450static int shrink_icache_memory(int nr, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451{
452 if (nr) {
453 /*
454 * Nasty deadlock avoidance. We may hold various FS locks,
455 * and we don't want to recurse into the FS that called us
456 * in clear_inode() and friends..
457 */
458 if (!(gfp_mask & __GFP_FS))
459 return -1;
460 prune_icache(nr);
461 }
462 return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
463}
464
Rusty Russell8e1f9362007-07-17 04:03:17 -0700465static struct shrinker icache_shrinker = {
466 .shrink = shrink_icache_memory,
467 .seeks = DEFAULT_SEEKS,
468};
469
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470static void __wait_on_freeing_inode(struct inode *inode);
471/*
472 * Called with the inode lock held.
473 * NOTE: we are not increasing the inode-refcount, you must call __iget()
474 * by hand after calling find_inode now! This simplifies iunique and won't
475 * add any additional branch in the common code.
476 */
477static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
478{
479 struct hlist_node *node;
480 struct inode * inode = NULL;
481
482repeat:
483 hlist_for_each (node, head) {
484 inode = hlist_entry(node, struct inode, i_hash);
485 if (inode->i_sb != sb)
486 continue;
487 if (!test(inode, data))
488 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700489 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 __wait_on_freeing_inode(inode);
491 goto repeat;
492 }
493 break;
494 }
495 return node ? inode : NULL;
496}
497
498/*
499 * find_inode_fast is the fast path version of find_inode, see the comment at
500 * iget_locked for details.
501 */
502static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
503{
504 struct hlist_node *node;
505 struct inode * inode = NULL;
506
507repeat:
508 hlist_for_each (node, head) {
509 inode = hlist_entry(node, struct inode, i_hash);
510 if (inode->i_ino != ino)
511 continue;
512 if (inode->i_sb != sb)
513 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700514 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 __wait_on_freeing_inode(inode);
516 goto repeat;
517 }
518 break;
519 }
520 return node ? inode : NULL;
521}
522
523/**
524 * new_inode - obtain an inode
525 * @sb: superblock
526 *
Mel Gorman769848c2007-07-17 04:03:05 -0700527 * Allocates a new inode for given superblock. The default gfp_mask
528 * for allocations related to inode->i_mapping is GFP_HIGHUSER_PAGECACHE.
529 * If HIGHMEM pages are unsuitable or it is known that pages allocated
530 * for the page cache are not reclaimable or migratable,
531 * mapping_set_gfp_mask() must be called with suitable flags on the
532 * newly created inode's mapping
533 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 */
535struct inode *new_inode(struct super_block *sb)
536{
Jeff Layton866b04f2007-05-08 00:32:29 -0700537 /*
538 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
539 * error if st_ino won't fit in target struct field. Use 32bit counter
540 * here to attempt to avoid that.
541 */
542 static unsigned int last_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 struct inode * inode;
544
545 spin_lock_prefetch(&inode_lock);
546
547 inode = alloc_inode(sb);
548 if (inode) {
549 spin_lock(&inode_lock);
550 inodes_stat.nr_inodes++;
551 list_add(&inode->i_list, &inode_in_use);
552 list_add(&inode->i_sb_list, &sb->s_inodes);
553 inode->i_ino = ++last_ino;
554 inode->i_state = 0;
555 spin_unlock(&inode_lock);
556 }
557 return inode;
558}
559
560EXPORT_SYMBOL(new_inode);
561
562void unlock_new_inode(struct inode *inode)
563{
564 /*
565 * This is special! We do not need the spinlock
566 * when clearing I_LOCK, because we're guaranteed
567 * that nobody else tries to do anything about the
568 * state of the inode when it is locked, as we
569 * just created it (so there can be no old holders
570 * that haven't tested I_LOCK).
571 */
572 inode->i_state &= ~(I_LOCK|I_NEW);
573 wake_up_inode(inode);
574}
575
576EXPORT_SYMBOL(unlock_new_inode);
577
578/*
579 * This is called without the inode lock held.. Be careful.
580 *
581 * We no longer cache the sb_flags in i_flags - see fs.h
582 * -- rmk@arm.uk.linux.org
583 */
584static 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)
585{
586 struct inode * inode;
587
588 inode = alloc_inode(sb);
589 if (inode) {
590 struct inode * old;
591
592 spin_lock(&inode_lock);
593 /* We released the lock, so.. */
594 old = find_inode(sb, head, test, data);
595 if (!old) {
596 if (set(inode, data))
597 goto set_failed;
598
599 inodes_stat.nr_inodes++;
600 list_add(&inode->i_list, &inode_in_use);
601 list_add(&inode->i_sb_list, &sb->s_inodes);
602 hlist_add_head(&inode->i_hash, head);
603 inode->i_state = I_LOCK|I_NEW;
604 spin_unlock(&inode_lock);
605
606 /* Return the locked inode with I_NEW set, the
607 * caller is responsible for filling in the contents
608 */
609 return inode;
610 }
611
612 /*
613 * Uhhuh, somebody else created the same inode under
614 * us. Use the old inode instead of the one we just
615 * allocated.
616 */
617 __iget(old);
618 spin_unlock(&inode_lock);
619 destroy_inode(inode);
620 inode = old;
621 wait_on_inode(inode);
622 }
623 return inode;
624
625set_failed:
626 spin_unlock(&inode_lock);
627 destroy_inode(inode);
628 return NULL;
629}
630
631/*
632 * get_new_inode_fast is the fast path version of get_new_inode, see the
633 * comment at iget_locked for details.
634 */
635static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
636{
637 struct inode * inode;
638
639 inode = alloc_inode(sb);
640 if (inode) {
641 struct inode * old;
642
643 spin_lock(&inode_lock);
644 /* We released the lock, so.. */
645 old = find_inode_fast(sb, head, ino);
646 if (!old) {
647 inode->i_ino = ino;
648 inodes_stat.nr_inodes++;
649 list_add(&inode->i_list, &inode_in_use);
650 list_add(&inode->i_sb_list, &sb->s_inodes);
651 hlist_add_head(&inode->i_hash, head);
652 inode->i_state = I_LOCK|I_NEW;
653 spin_unlock(&inode_lock);
654
655 /* Return the locked inode with I_NEW set, the
656 * caller is responsible for filling in the contents
657 */
658 return inode;
659 }
660
661 /*
662 * Uhhuh, somebody else created the same inode under
663 * us. Use the old inode instead of the one we just
664 * allocated.
665 */
666 __iget(old);
667 spin_unlock(&inode_lock);
668 destroy_inode(inode);
669 inode = old;
670 wait_on_inode(inode);
671 }
672 return inode;
673}
674
Andreas Mohred97bd32006-10-02 02:17:17 -0700675static unsigned long hash(struct super_block *sb, unsigned long hashval)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676{
677 unsigned long tmp;
678
679 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
680 L1_CACHE_BYTES;
681 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
682 return tmp & I_HASHMASK;
683}
684
685/**
686 * iunique - get a unique inode number
687 * @sb: superblock
688 * @max_reserved: highest reserved inode number
689 *
690 * Obtain an inode number that is unique on the system for a given
691 * superblock. This is used by file systems that have no natural
692 * permanent inode numbering system. An inode number is returned that
693 * is higher than the reserved limit but unique.
694 *
695 * BUGS:
696 * With a large number of inodes live on the file system this function
697 * currently becomes quite slow.
698 */
699ino_t iunique(struct super_block *sb, ino_t max_reserved)
700{
Jeff Layton866b04f2007-05-08 00:32:29 -0700701 /*
702 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
703 * error if st_ino won't fit in target struct field. Use 32bit counter
704 * here to attempt to avoid that.
705 */
706 static unsigned int counter;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 struct inode *inode;
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700708 struct hlist_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 ino_t res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700711 spin_lock(&inode_lock);
712 do {
713 if (counter <= max_reserved)
714 counter = max_reserved + 1;
715 res = counter++;
716 head = inode_hashtable + hash(sb, res);
717 inode = find_inode_fast(sb, head, res);
718 } while (inode != NULL);
719 spin_unlock(&inode_lock);
720
721 return res;
722}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723EXPORT_SYMBOL(iunique);
724
725struct inode *igrab(struct inode *inode)
726{
727 spin_lock(&inode_lock);
Jan Blunck4a3b0a42007-02-10 01:44:59 -0800728 if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 __iget(inode);
730 else
731 /*
732 * Handle the case where s_op->clear_inode is not been
733 * called yet, and somebody is calling igrab
734 * while the inode is getting freed.
735 */
736 inode = NULL;
737 spin_unlock(&inode_lock);
738 return inode;
739}
740
741EXPORT_SYMBOL(igrab);
742
743/**
744 * ifind - internal function, you want ilookup5() or iget5().
745 * @sb: super block of file system to search
746 * @head: the head of the list to search
747 * @test: callback used for comparisons between inodes
748 * @data: opaque data pointer to pass to @test
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700749 * @wait: if true wait for the inode to be unlocked, if false do not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 *
751 * ifind() searches for the inode specified by @data in the inode
752 * cache. This is a generalized version of ifind_fast() for file systems where
753 * the inode number is not sufficient for unique identification of an inode.
754 *
755 * If the inode is in the cache, the inode is returned with an incremented
756 * reference count.
757 *
758 * Otherwise NULL is returned.
759 *
760 * Note, @test is called with the inode_lock held, so can't sleep.
761 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800762static struct inode *ifind(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 struct hlist_head *head, int (*test)(struct inode *, void *),
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700764 void *data, const int wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765{
766 struct inode *inode;
767
768 spin_lock(&inode_lock);
769 inode = find_inode(sb, head, test, data);
770 if (inode) {
771 __iget(inode);
772 spin_unlock(&inode_lock);
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700773 if (likely(wait))
774 wait_on_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 return inode;
776 }
777 spin_unlock(&inode_lock);
778 return NULL;
779}
780
781/**
782 * ifind_fast - internal function, you want ilookup() or iget().
783 * @sb: super block of file system to search
784 * @head: head of the list to search
785 * @ino: inode number to search for
786 *
787 * ifind_fast() searches for the inode @ino in the inode cache. This is for
788 * file systems where the inode number is sufficient for unique identification
789 * of an inode.
790 *
791 * If the inode is in the cache, the inode is returned with an incremented
792 * reference count.
793 *
794 * Otherwise NULL is returned.
795 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800796static struct inode *ifind_fast(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 struct hlist_head *head, unsigned long ino)
798{
799 struct inode *inode;
800
801 spin_lock(&inode_lock);
802 inode = find_inode_fast(sb, head, ino);
803 if (inode) {
804 __iget(inode);
805 spin_unlock(&inode_lock);
806 wait_on_inode(inode);
807 return inode;
808 }
809 spin_unlock(&inode_lock);
810 return NULL;
811}
812
813/**
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700814 * ilookup5_nowait - search for an inode in the inode cache
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 * @sb: super block of file system to search
816 * @hashval: hash value (usually inode number) to search for
817 * @test: callback used for comparisons between inodes
818 * @data: opaque data pointer to pass to @test
819 *
820 * ilookup5() uses ifind() to search for the inode specified by @hashval and
821 * @data in the inode cache. This is a generalized version of ilookup() for
822 * file systems where the inode number is not sufficient for unique
823 * identification of an inode.
824 *
825 * If the inode is in the cache, the inode is returned with an incremented
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700826 * reference count. Note, the inode lock is not waited upon so you have to be
827 * very careful what you do with the returned inode. You probably should be
828 * using ilookup5() instead.
829 *
830 * Otherwise NULL is returned.
831 *
832 * Note, @test is called with the inode_lock held, so can't sleep.
833 */
834struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
835 int (*test)(struct inode *, void *), void *data)
836{
837 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
838
839 return ifind(sb, head, test, data, 0);
840}
841
842EXPORT_SYMBOL(ilookup5_nowait);
843
844/**
845 * ilookup5 - search for an inode in the inode cache
846 * @sb: super block of file system to search
847 * @hashval: hash value (usually inode number) to search for
848 * @test: callback used for comparisons between inodes
849 * @data: opaque data pointer to pass to @test
850 *
851 * ilookup5() uses ifind() to search for the inode specified by @hashval and
852 * @data in the inode cache. This is a generalized version of ilookup() for
853 * file systems where the inode number is not sufficient for unique
854 * identification of an inode.
855 *
856 * If the inode is in the cache, the inode lock is waited upon and the inode is
857 * returned with an incremented reference count.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 *
859 * Otherwise NULL is returned.
860 *
861 * Note, @test is called with the inode_lock held, so can't sleep.
862 */
863struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
864 int (*test)(struct inode *, void *), void *data)
865{
866 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
867
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700868 return ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869}
870
871EXPORT_SYMBOL(ilookup5);
872
873/**
874 * ilookup - search for an inode in the inode cache
875 * @sb: super block of file system to search
876 * @ino: inode number to search for
877 *
878 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
879 * This is for file systems where the inode number is sufficient for unique
880 * identification of an inode.
881 *
882 * If the inode is in the cache, the inode is returned with an incremented
883 * reference count.
884 *
885 * Otherwise NULL is returned.
886 */
887struct inode *ilookup(struct super_block *sb, unsigned long ino)
888{
889 struct hlist_head *head = inode_hashtable + hash(sb, ino);
890
891 return ifind_fast(sb, head, ino);
892}
893
894EXPORT_SYMBOL(ilookup);
895
896/**
897 * iget5_locked - obtain an inode from a mounted file system
898 * @sb: super block of file system
899 * @hashval: hash value (usually inode number) to get
900 * @test: callback used for comparisons between inodes
901 * @set: callback used to initialize a new struct inode
902 * @data: opaque data pointer to pass to @test and @set
903 *
904 * This is iget() without the read_inode() portion of get_new_inode().
905 *
906 * iget5_locked() uses ifind() to search for the inode specified by @hashval
907 * and @data in the inode cache and if present it is returned with an increased
908 * reference count. This is a generalized version of iget_locked() for file
909 * systems where the inode number is not sufficient for unique identification
910 * of an inode.
911 *
912 * If the inode is not in cache, get_new_inode() is called to allocate a new
913 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
914 * file system gets to fill it in before unlocking it via unlock_new_inode().
915 *
916 * Note both @test and @set are called with the inode_lock held, so can't sleep.
917 */
918struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
919 int (*test)(struct inode *, void *),
920 int (*set)(struct inode *, void *), void *data)
921{
922 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
923 struct inode *inode;
924
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700925 inode = ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 if (inode)
927 return inode;
928 /*
929 * get_new_inode() will do the right thing, re-trying the search
930 * in case it had to block at any point.
931 */
932 return get_new_inode(sb, head, test, set, data);
933}
934
935EXPORT_SYMBOL(iget5_locked);
936
937/**
938 * iget_locked - obtain an inode from a mounted file system
939 * @sb: super block of file system
940 * @ino: inode number to get
941 *
942 * This is iget() without the read_inode() portion of get_new_inode_fast().
943 *
944 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
945 * the inode cache and if present it is returned with an increased reference
946 * count. This is for file systems where the inode number is sufficient for
947 * unique identification of an inode.
948 *
949 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
950 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
951 * The file system gets to fill it in before unlocking it via
952 * unlock_new_inode().
953 */
954struct inode *iget_locked(struct super_block *sb, unsigned long ino)
955{
956 struct hlist_head *head = inode_hashtable + hash(sb, ino);
957 struct inode *inode;
958
959 inode = ifind_fast(sb, head, ino);
960 if (inode)
961 return inode;
962 /*
963 * get_new_inode_fast() will do the right thing, re-trying the search
964 * in case it had to block at any point.
965 */
966 return get_new_inode_fast(sb, head, ino);
967}
968
969EXPORT_SYMBOL(iget_locked);
970
971/**
972 * __insert_inode_hash - hash an inode
973 * @inode: unhashed inode
974 * @hashval: unsigned long value used to locate this object in the
975 * inode_hashtable.
976 *
977 * Add an inode to the inode hash for this superblock.
978 */
979void __insert_inode_hash(struct inode *inode, unsigned long hashval)
980{
981 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
982 spin_lock(&inode_lock);
983 hlist_add_head(&inode->i_hash, head);
984 spin_unlock(&inode_lock);
985}
986
987EXPORT_SYMBOL(__insert_inode_hash);
988
989/**
990 * remove_inode_hash - remove an inode from the hash
991 * @inode: inode to unhash
992 *
993 * Remove an inode from the superblock.
994 */
995void remove_inode_hash(struct inode *inode)
996{
997 spin_lock(&inode_lock);
998 hlist_del_init(&inode->i_hash);
999 spin_unlock(&inode_lock);
1000}
1001
1002EXPORT_SYMBOL(remove_inode_hash);
1003
1004/*
1005 * Tell the filesystem that this inode is no longer of any interest and should
1006 * be completely destroyed.
1007 *
1008 * We leave the inode in the inode hash table until *after* the filesystem's
1009 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1010 * instigate) will always find up-to-date information either in the hash or on
1011 * disk.
1012 *
1013 * I_FREEING is set so that no-one will take a new reference to the inode while
1014 * it is being deleted.
1015 */
1016void generic_delete_inode(struct inode *inode)
1017{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001018 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
1020 list_del_init(&inode->i_list);
1021 list_del_init(&inode->i_sb_list);
Andreas Mohred97bd32006-10-02 02:17:17 -07001022 inode->i_state |= I_FREEING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 inodes_stat.nr_inodes--;
1024 spin_unlock(&inode_lock);
1025
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 security_inode_delete(inode);
1027
1028 if (op->delete_inode) {
1029 void (*delete)(struct inode *) = op->delete_inode;
1030 if (!is_bad_inode(inode))
1031 DQUOT_INIT(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001032 /* Filesystems implementing their own
1033 * s_op->delete_inode are required to call
1034 * truncate_inode_pages and clear_inode()
1035 * internally */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 delete(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001037 } else {
1038 truncate_inode_pages(&inode->i_data, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 clear_inode(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001040 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 spin_lock(&inode_lock);
1042 hlist_del_init(&inode->i_hash);
1043 spin_unlock(&inode_lock);
1044 wake_up_inode(inode);
Eric Sesterhennb7542f82006-04-02 13:38:18 +02001045 BUG_ON(inode->i_state != I_CLEAR);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 destroy_inode(inode);
1047}
1048
1049EXPORT_SYMBOL(generic_delete_inode);
1050
1051static void generic_forget_inode(struct inode *inode)
1052{
1053 struct super_block *sb = inode->i_sb;
1054
1055 if (!hlist_unhashed(&inode->i_hash)) {
1056 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
1057 list_move(&inode->i_list, &inode_unused);
1058 inodes_stat.nr_unused++;
Christoph Hellwigacb0c852007-05-08 00:25:52 -07001059 if (sb->s_flags & MS_ACTIVE) {
Alexander Viro991114c2005-06-23 00:09:01 -07001060 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 return;
Alexander Viro991114c2005-06-23 00:09:01 -07001062 }
1063 inode->i_state |= I_WILL_FREE;
1064 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 write_inode_now(inode, 1);
1066 spin_lock(&inode_lock);
Alexander Viro991114c2005-06-23 00:09:01 -07001067 inode->i_state &= ~I_WILL_FREE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 inodes_stat.nr_unused--;
1069 hlist_del_init(&inode->i_hash);
1070 }
1071 list_del_init(&inode->i_list);
1072 list_del_init(&inode->i_sb_list);
Alexander Viro991114c2005-06-23 00:09:01 -07001073 inode->i_state |= I_FREEING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 inodes_stat.nr_inodes--;
1075 spin_unlock(&inode_lock);
1076 if (inode->i_data.nrpages)
1077 truncate_inode_pages(&inode->i_data, 0);
1078 clear_inode(inode);
Andrea Arcangeli7f04c262005-10-30 15:03:05 -08001079 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 destroy_inode(inode);
1081}
1082
1083/*
1084 * Normal UNIX filesystem behaviour: delete the
1085 * inode when the usage count drops to zero, and
1086 * i_nlink is zero.
1087 */
Mark Fashehcb2c0232005-07-07 17:56:03 -07001088void generic_drop_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089{
1090 if (!inode->i_nlink)
1091 generic_delete_inode(inode);
1092 else
1093 generic_forget_inode(inode);
1094}
1095
Mark Fashehcb2c0232005-07-07 17:56:03 -07001096EXPORT_SYMBOL_GPL(generic_drop_inode);
1097
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098/*
1099 * Called when we're dropping the last reference
1100 * to an inode.
1101 *
1102 * Call the FS "drop()" function, defaulting to
1103 * the legacy UNIX filesystem behaviour..
1104 *
1105 * NOTE! NOTE! NOTE! We're called with the inode lock
1106 * held, and the drop function is supposed to release
1107 * the lock!
1108 */
1109static inline void iput_final(struct inode *inode)
1110{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001111 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 void (*drop)(struct inode *) = generic_drop_inode;
1113
1114 if (op && op->drop_inode)
1115 drop = op->drop_inode;
1116 drop(inode);
1117}
1118
1119/**
1120 * iput - put an inode
1121 * @inode: inode to put
1122 *
1123 * Puts an inode, dropping its usage count. If the inode use count hits
1124 * zero, the inode is then freed and may also be destroyed.
1125 *
1126 * Consequently, iput() can sleep.
1127 */
1128void iput(struct inode *inode)
1129{
1130 if (inode) {
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001131 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
1133 BUG_ON(inode->i_state == I_CLEAR);
1134
1135 if (op && op->put_inode)
1136 op->put_inode(inode);
1137
1138 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1139 iput_final(inode);
1140 }
1141}
1142
1143EXPORT_SYMBOL(iput);
1144
1145/**
1146 * bmap - find a block number in a file
1147 * @inode: inode of file
1148 * @block: block to find
1149 *
1150 * Returns the block number on the device holding the inode that
1151 * is the disk block number for the block of the file requested.
1152 * That is, asked for block 4 of inode 1 the function will return the
1153 * disk block relative to the disk start that holds that block of the
1154 * file.
1155 */
1156sector_t bmap(struct inode * inode, sector_t block)
1157{
1158 sector_t res = 0;
1159 if (inode->i_mapping->a_ops->bmap)
1160 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1161 return res;
1162}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163EXPORT_SYMBOL(bmap);
1164
1165/**
Christoph Hellwig869243a2006-01-09 20:52:03 -08001166 * touch_atime - update the access time
1167 * @mnt: mount the inode is accessed on
Martin Waitz7045f372006-02-01 03:06:57 -08001168 * @dentry: dentry accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 *
1170 * Update the accessed time on an inode and mark it for writeback.
1171 * This function automatically handles read only file systems and media,
1172 * as well as the "noatime" flag and inode specific "noatime" markers.
1173 */
Christoph Hellwig869243a2006-01-09 20:52:03 -08001174void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175{
Christoph Hellwig869243a2006-01-09 20:52:03 -08001176 struct inode *inode = dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 struct timespec now;
1178
Andrew Mortonb2276132006-12-13 00:34:33 -08001179 if (inode->i_flags & S_NOATIME)
1180 return;
Eric Dumazet37756ce2007-02-10 01:44:49 -08001181 if (IS_NOATIME(inode))
Andrew Mortonb2276132006-12-13 00:34:33 -08001182 return;
1183 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001184 return;
1185
1186 /*
1187 * We may have a NULL vfsmount when coming from NFSD
1188 */
Andrew Mortonb2276132006-12-13 00:34:33 -08001189 if (mnt) {
1190 if (mnt->mnt_flags & MNT_NOATIME)
1191 return;
1192 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1193 return;
Valerie Henson47ae32d2006-12-13 00:34:34 -08001194
1195 if (mnt->mnt_flags & MNT_RELATIME) {
1196 /*
1197 * With relative atime, only update atime if the
1198 * previous atime is earlier than either the ctime or
1199 * mtime.
1200 */
1201 if (timespec_compare(&inode->i_mtime,
1202 &inode->i_atime) < 0 &&
1203 timespec_compare(&inode->i_ctime,
1204 &inode->i_atime) < 0)
1205 return;
1206 }
Andrew Mortonb2276132006-12-13 00:34:33 -08001207 }
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 now = current_fs_time(inode->i_sb);
Valerie Henson47ae32d2006-12-13 00:34:34 -08001210 if (timespec_equal(&inode->i_atime, &now))
1211 return;
1212
1213 inode->i_atime = now;
1214 mark_inode_dirty_sync(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215}
Christoph Hellwig869243a2006-01-09 20:52:03 -08001216EXPORT_SYMBOL(touch_atime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217
1218/**
Christoph Hellwig870f4812006-01-09 20:52:01 -08001219 * file_update_time - update mtime and ctime time
1220 * @file: file accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 *
Christoph Hellwig870f4812006-01-09 20:52:01 -08001222 * Update the mtime and ctime members of an inode and mark the inode
1223 * for writeback. Note that this function is meant exclusively for
1224 * usage in the file write path of filesystems, and filesystems may
1225 * choose to explicitly ignore update via this function with the
1226 * S_NOCTIME inode flag, e.g. for network filesystem where these
1227 * timestamps are handled by the server.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 */
1229
Christoph Hellwig870f4812006-01-09 20:52:01 -08001230void file_update_time(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001232 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 struct timespec now;
1234 int sync_it = 0;
1235
1236 if (IS_NOCMTIME(inode))
1237 return;
1238 if (IS_RDONLY(inode))
1239 return;
1240
1241 now = current_fs_time(inode->i_sb);
Andreas Mohred97bd32006-10-02 02:17:17 -07001242 if (!timespec_equal(&inode->i_mtime, &now)) {
1243 inode->i_mtime = now;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001245 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246
Andreas Mohred97bd32006-10-02 02:17:17 -07001247 if (!timespec_equal(&inode->i_ctime, &now)) {
1248 inode->i_ctime = now;
Christoph Hellwig870f4812006-01-09 20:52:01 -08001249 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001250 }
Christoph Hellwig870f4812006-01-09 20:52:01 -08001251
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 if (sync_it)
1253 mark_inode_dirty_sync(inode);
1254}
1255
Christoph Hellwig870f4812006-01-09 20:52:01 -08001256EXPORT_SYMBOL(file_update_time);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257
1258int inode_needs_sync(struct inode *inode)
1259{
1260 if (IS_SYNC(inode))
1261 return 1;
1262 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1263 return 1;
1264 return 0;
1265}
1266
1267EXPORT_SYMBOL(inode_needs_sync);
1268
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269int inode_wait(void *word)
1270{
1271 schedule();
1272 return 0;
1273}
1274
1275/*
Miklos Szeredi168a9fd2005-07-12 13:58:10 -07001276 * If we try to find an inode in the inode hash while it is being
1277 * deleted, we have to wait until the filesystem completes its
1278 * deletion before reporting that it isn't found. This function waits
1279 * until the deletion _might_ have completed. Callers are responsible
1280 * to recheck inode state.
1281 *
1282 * It doesn't matter if I_LOCK is not set initially, a call to
1283 * wake_up_inode() after removing from the hash list will DTRT.
1284 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 * This is called with inode_lock held.
1286 */
1287static void __wait_on_freeing_inode(struct inode *inode)
1288{
1289 wait_queue_head_t *wq;
1290 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 wq = bit_waitqueue(&inode->i_state, __I_LOCK);
1292 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1293 spin_unlock(&inode_lock);
1294 schedule();
1295 finish_wait(wq, &wait.wait);
1296 spin_lock(&inode_lock);
1297}
1298
1299void wake_up_inode(struct inode *inode)
1300{
1301 /*
1302 * Prevent speculative execution through spin_unlock(&inode_lock);
1303 */
1304 smp_mb();
1305 wake_up_bit(&inode->i_state, __I_LOCK);
1306}
1307
Mark Fasheh62752ee2006-10-17 10:31:38 +02001308/*
1309 * We rarely want to lock two inodes that do not have a parent/child
1310 * relationship (such as directory, child inode) simultaneously. The
1311 * vast majority of file systems should be able to get along fine
1312 * without this. Do not use these functions except as a last resort.
1313 */
1314void inode_double_lock(struct inode *inode1, struct inode *inode2)
1315{
1316 if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
1317 if (inode1)
1318 mutex_lock(&inode1->i_mutex);
1319 else if (inode2)
1320 mutex_lock(&inode2->i_mutex);
1321 return;
1322 }
1323
1324 if (inode1 < inode2) {
1325 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1326 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1327 } else {
1328 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1329 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1330 }
1331}
1332EXPORT_SYMBOL(inode_double_lock);
1333
1334void inode_double_unlock(struct inode *inode1, struct inode *inode2)
1335{
1336 if (inode1)
1337 mutex_unlock(&inode1->i_mutex);
1338
1339 if (inode2 && inode2 != inode1)
1340 mutex_unlock(&inode2->i_mutex);
1341}
1342EXPORT_SYMBOL(inode_double_unlock);
1343
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344static __initdata unsigned long ihash_entries;
1345static int __init set_ihash_entries(char *str)
1346{
1347 if (!str)
1348 return 0;
1349 ihash_entries = simple_strtoul(str, &str, 0);
1350 return 1;
1351}
1352__setup("ihash_entries=", set_ihash_entries);
1353
1354/*
1355 * Initialize the waitqueues and inode hash table.
1356 */
1357void __init inode_init_early(void)
1358{
1359 int loop;
1360
1361 /* If hashes are distributed across NUMA nodes, defer
1362 * hash allocation until vmalloc space is available.
1363 */
1364 if (hashdist)
1365 return;
1366
1367 inode_hashtable =
1368 alloc_large_system_hash("Inode-cache",
1369 sizeof(struct hlist_head),
1370 ihash_entries,
1371 14,
1372 HASH_EARLY,
1373 &i_hash_shift,
1374 &i_hash_mask,
1375 0);
1376
1377 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1378 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1379}
1380
1381void __init inode_init(unsigned long mempages)
1382{
1383 int loop;
1384
1385 /* inode slab cache */
Paul Jacksonb0196002006-03-24 03:16:09 -08001386 inode_cachep = kmem_cache_create("inode_cache",
1387 sizeof(struct inode),
1388 0,
1389 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1390 SLAB_MEM_SPREAD),
1391 init_once,
1392 NULL);
Rusty Russell8e1f9362007-07-17 04:03:17 -07001393 register_shrinker(&icache_shrinker);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394
1395 /* Hash may have been set up in inode_init_early */
1396 if (!hashdist)
1397 return;
1398
1399 inode_hashtable =
1400 alloc_large_system_hash("Inode-cache",
1401 sizeof(struct hlist_head),
1402 ihash_entries,
1403 14,
1404 0,
1405 &i_hash_shift,
1406 &i_hash_mask,
1407 0);
1408
1409 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1410 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1411}
1412
1413void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1414{
1415 inode->i_mode = mode;
1416 if (S_ISCHR(mode)) {
1417 inode->i_fop = &def_chr_fops;
1418 inode->i_rdev = rdev;
1419 } else if (S_ISBLK(mode)) {
1420 inode->i_fop = &def_blk_fops;
1421 inode->i_rdev = rdev;
1422 } else if (S_ISFIFO(mode))
1423 inode->i_fop = &def_fifo_fops;
1424 else if (S_ISSOCK(mode))
1425 inode->i_fop = &bad_sock_fops;
1426 else
1427 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
1428 mode);
1429}
1430EXPORT_SYMBOL(init_special_inode);