tty: VT, remove unused variable
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / inode.c
blob33c963d08ab49ecc4244a5e817db4af525794ce5
1 /*
2 * linux/fs/inode.c
4 * (C) 1997 Linus Torvalds
5 */
7 #include <linux/fs.h>
8 #include <linux/mm.h>
9 #include <linux/dcache.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/writeback.h>
13 #include <linux/module.h>
14 #include <linux/backing-dev.h>
15 #include <linux/wait.h>
16 #include <linux/rwsem.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>
23 #include <linux/fsnotify.h>
24 #include <linux/mount.h>
25 #include <linux/async.h>
26 #include <linux/posix_acl.h>
27 #include <linux/ima.h>
28 #include <linux/cred.h>
29 #include "internal.h"
32 * inode locking rules.
34 * inode->i_lock protects:
35 * inode->i_state, inode->i_hash, __iget()
36 * inode_lru_lock protects:
37 * inode_lru, inode->i_lru
38 * inode_sb_list_lock protects:
39 * sb->s_inodes, inode->i_sb_list
40 * inode_wb_list_lock protects:
41 * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
42 * inode_hash_lock protects:
43 * inode_hashtable, inode->i_hash
45 * Lock ordering:
47 * inode_sb_list_lock
48 * inode->i_lock
49 * inode_lru_lock
51 * inode_wb_list_lock
52 * inode->i_lock
54 * inode_hash_lock
55 * inode_sb_list_lock
56 * inode->i_lock
58 * iunique_lock
59 * inode_hash_lock
63 * This is needed for the following functions:
64 * - inode_has_buffers
65 * - invalidate_bdev
67 * FIXME: remove all knowledge of the buffer layer from this file
69 #include <linux/buffer_head.h>
72 * New inode.c implementation.
74 * This implementation has the basic premise of trying
75 * to be extremely low-overhead and SMP-safe, yet be
76 * simple enough to be "obviously correct".
78 * Famous last words.
81 /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
83 /* #define INODE_PARANOIA 1 */
84 /* #define INODE_DEBUG 1 */
87 * Inode lookup is no longer as critical as it used to be:
88 * most of the lookups are going to be through the dcache.
90 #define I_HASHBITS i_hash_shift
91 #define I_HASHMASK i_hash_mask
93 static unsigned int i_hash_mask __read_mostly;
94 static unsigned int i_hash_shift __read_mostly;
95 static struct hlist_head *inode_hashtable __read_mostly;
96 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
99 * Each inode can be on two separate lists. One is
100 * the hash list of the inode, used for lookups. The
101 * other linked list is the "type" list:
102 * "in_use" - valid inode, i_count > 0, i_nlink > 0
103 * "dirty" - as "in_use" but also dirty
104 * "unused" - valid inode, i_count = 0
106 * A "dirty" list is maintained for each super block,
107 * allowing for low-overhead inode sync() operations.
110 static LIST_HEAD(inode_lru);
111 static DEFINE_SPINLOCK(inode_lru_lock);
113 __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);
114 __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_wb_list_lock);
117 * iprune_sem provides exclusion between the icache shrinking and the
118 * umount path.
120 * We don't actually need it to protect anything in the umount path,
121 * but only need to cycle through it to make sure any inode that
122 * prune_icache took off the LRU list has been fully torn down by the
123 * time we are past evict_inodes.
125 static DECLARE_RWSEM(iprune_sem);
128 * Empty aops. Can be used for the cases where the user does not
129 * define any of the address_space operations.
131 const struct address_space_operations empty_aops = {
133 EXPORT_SYMBOL(empty_aops);
136 * Statistics gathering..
138 struct inodes_stat_t inodes_stat;
140 static DEFINE_PER_CPU(unsigned int, nr_inodes);
142 static struct kmem_cache *inode_cachep __read_mostly;
144 static int get_nr_inodes(void)
146 int i;
147 int sum = 0;
148 for_each_possible_cpu(i)
149 sum += per_cpu(nr_inodes, i);
150 return sum < 0 ? 0 : sum;
153 static inline int get_nr_inodes_unused(void)
155 return inodes_stat.nr_unused;
158 int get_nr_dirty_inodes(void)
160 /* not actually dirty inodes, but a wild approximation */
161 int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
162 return nr_dirty > 0 ? nr_dirty : 0;
166 * Handle nr_inode sysctl
168 #ifdef CONFIG_SYSCTL
169 int proc_nr_inodes(ctl_table *table, int write,
170 void __user *buffer, size_t *lenp, loff_t *ppos)
172 inodes_stat.nr_inodes = get_nr_inodes();
173 return proc_dointvec(table, write, buffer, lenp, ppos);
175 #endif
178 * inode_init_always - perform inode structure intialisation
179 * @sb: superblock inode belongs to
180 * @inode: inode to initialise
182 * These are initializations that need to be done on every inode
183 * allocation as the fields are not initialised by slab allocation.
185 int inode_init_always(struct super_block *sb, struct inode *inode)
187 static const struct inode_operations empty_iops;
188 static const struct file_operations empty_fops;
189 struct address_space *const mapping = &inode->i_data;
191 inode->i_sb = sb;
192 inode->i_blkbits = sb->s_blocksize_bits;
193 inode->i_flags = 0;
194 atomic_set(&inode->i_count, 1);
195 inode->i_op = &empty_iops;
196 inode->i_fop = &empty_fops;
197 inode->i_nlink = 1;
198 inode->i_uid = 0;
199 inode->i_gid = 0;
200 atomic_set(&inode->i_writecount, 0);
201 inode->i_size = 0;
202 inode->i_blocks = 0;
203 inode->i_bytes = 0;
204 inode->i_generation = 0;
205 #ifdef CONFIG_QUOTA
206 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
207 #endif
208 inode->i_pipe = NULL;
209 inode->i_bdev = NULL;
210 inode->i_cdev = NULL;
211 inode->i_rdev = 0;
212 inode->dirtied_when = 0;
214 if (security_inode_alloc(inode))
215 goto out;
216 spin_lock_init(&inode->i_lock);
217 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
219 mutex_init(&inode->i_mutex);
220 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
222 init_rwsem(&inode->i_alloc_sem);
223 lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
225 mapping->a_ops = &empty_aops;
226 mapping->host = inode;
227 mapping->flags = 0;
228 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
229 mapping->assoc_mapping = NULL;
230 mapping->backing_dev_info = &default_backing_dev_info;
231 mapping->writeback_index = 0;
234 * If the block_device provides a backing_dev_info for client
235 * inodes then use that. Otherwise the inode share the bdev's
236 * backing_dev_info.
238 if (sb->s_bdev) {
239 struct backing_dev_info *bdi;
241 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
242 mapping->backing_dev_info = bdi;
244 inode->i_private = NULL;
245 inode->i_mapping = mapping;
246 #ifdef CONFIG_FS_POSIX_ACL
247 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
248 #endif
250 #ifdef CONFIG_FSNOTIFY
251 inode->i_fsnotify_mask = 0;
252 #endif
254 this_cpu_inc(nr_inodes);
256 return 0;
257 out:
258 return -ENOMEM;
260 EXPORT_SYMBOL(inode_init_always);
262 static struct inode *alloc_inode(struct super_block *sb)
264 struct inode *inode;
266 if (sb->s_op->alloc_inode)
267 inode = sb->s_op->alloc_inode(sb);
268 else
269 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
271 if (!inode)
272 return NULL;
274 if (unlikely(inode_init_always(sb, inode))) {
275 if (inode->i_sb->s_op->destroy_inode)
276 inode->i_sb->s_op->destroy_inode(inode);
277 else
278 kmem_cache_free(inode_cachep, inode);
279 return NULL;
282 return inode;
285 void free_inode_nonrcu(struct inode *inode)
287 kmem_cache_free(inode_cachep, inode);
289 EXPORT_SYMBOL(free_inode_nonrcu);
291 void __destroy_inode(struct inode *inode)
293 BUG_ON(inode_has_buffers(inode));
294 security_inode_free(inode);
295 fsnotify_inode_delete(inode);
296 #ifdef CONFIG_FS_POSIX_ACL
297 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
298 posix_acl_release(inode->i_acl);
299 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
300 posix_acl_release(inode->i_default_acl);
301 #endif
302 this_cpu_dec(nr_inodes);
304 EXPORT_SYMBOL(__destroy_inode);
306 static void i_callback(struct rcu_head *head)
308 struct inode *inode = container_of(head, struct inode, i_rcu);
309 INIT_LIST_HEAD(&inode->i_dentry);
310 kmem_cache_free(inode_cachep, inode);
313 static void destroy_inode(struct inode *inode)
315 BUG_ON(!list_empty(&inode->i_lru));
316 __destroy_inode(inode);
317 if (inode->i_sb->s_op->destroy_inode)
318 inode->i_sb->s_op->destroy_inode(inode);
319 else
320 call_rcu(&inode->i_rcu, i_callback);
323 void address_space_init_once(struct address_space *mapping)
325 memset(mapping, 0, sizeof(*mapping));
326 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
327 spin_lock_init(&mapping->tree_lock);
328 spin_lock_init(&mapping->i_mmap_lock);
329 INIT_LIST_HEAD(&mapping->private_list);
330 spin_lock_init(&mapping->private_lock);
331 INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
332 INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
333 mutex_init(&mapping->unmap_mutex);
335 EXPORT_SYMBOL(address_space_init_once);
338 * These are initializations that only need to be done
339 * once, because the fields are idempotent across use
340 * of the inode, so let the slab aware of that.
342 void inode_init_once(struct inode *inode)
344 memset(inode, 0, sizeof(*inode));
345 INIT_HLIST_NODE(&inode->i_hash);
346 INIT_LIST_HEAD(&inode->i_dentry);
347 INIT_LIST_HEAD(&inode->i_devices);
348 INIT_LIST_HEAD(&inode->i_wb_list);
349 INIT_LIST_HEAD(&inode->i_lru);
350 address_space_init_once(&inode->i_data);
351 i_size_ordered_init(inode);
352 #ifdef CONFIG_FSNOTIFY
353 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
354 #endif
356 EXPORT_SYMBOL(inode_init_once);
358 static void init_once(void *foo)
360 struct inode *inode = (struct inode *) foo;
362 inode_init_once(inode);
366 * inode->i_lock must be held
368 void __iget(struct inode *inode)
370 atomic_inc(&inode->i_count);
374 * get additional reference to inode; caller must already hold one.
376 void ihold(struct inode *inode)
378 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
380 EXPORT_SYMBOL(ihold);
382 static void inode_lru_list_add(struct inode *inode)
384 spin_lock(&inode_lru_lock);
385 if (list_empty(&inode->i_lru)) {
386 list_add(&inode->i_lru, &inode_lru);
387 inodes_stat.nr_unused++;
389 spin_unlock(&inode_lru_lock);
392 static void inode_lru_list_del(struct inode *inode)
394 spin_lock(&inode_lru_lock);
395 if (!list_empty(&inode->i_lru)) {
396 list_del_init(&inode->i_lru);
397 inodes_stat.nr_unused--;
399 spin_unlock(&inode_lru_lock);
403 * inode_sb_list_add - add inode to the superblock list of inodes
404 * @inode: inode to add
406 void inode_sb_list_add(struct inode *inode)
408 spin_lock(&inode_sb_list_lock);
409 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
410 spin_unlock(&inode_sb_list_lock);
412 EXPORT_SYMBOL_GPL(inode_sb_list_add);
414 static inline void inode_sb_list_del(struct inode *inode)
416 spin_lock(&inode_sb_list_lock);
417 list_del_init(&inode->i_sb_list);
418 spin_unlock(&inode_sb_list_lock);
421 static unsigned long hash(struct super_block *sb, unsigned long hashval)
423 unsigned long tmp;
425 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
426 L1_CACHE_BYTES;
427 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
428 return tmp & I_HASHMASK;
432 * __insert_inode_hash - hash an inode
433 * @inode: unhashed inode
434 * @hashval: unsigned long value used to locate this object in the
435 * inode_hashtable.
437 * Add an inode to the inode hash for this superblock.
439 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
441 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
443 spin_lock(&inode_hash_lock);
444 spin_lock(&inode->i_lock);
445 hlist_add_head(&inode->i_hash, b);
446 spin_unlock(&inode->i_lock);
447 spin_unlock(&inode_hash_lock);
449 EXPORT_SYMBOL(__insert_inode_hash);
452 * remove_inode_hash - remove an inode from the hash
453 * @inode: inode to unhash
455 * Remove an inode from the superblock.
457 void remove_inode_hash(struct inode *inode)
459 spin_lock(&inode_hash_lock);
460 spin_lock(&inode->i_lock);
461 hlist_del_init(&inode->i_hash);
462 spin_unlock(&inode->i_lock);
463 spin_unlock(&inode_hash_lock);
465 EXPORT_SYMBOL(remove_inode_hash);
467 void end_writeback(struct inode *inode)
469 might_sleep();
470 BUG_ON(inode->i_data.nrpages);
471 BUG_ON(!list_empty(&inode->i_data.private_list));
472 BUG_ON(!(inode->i_state & I_FREEING));
473 BUG_ON(inode->i_state & I_CLEAR);
474 inode_sync_wait(inode);
475 /* don't need i_lock here, no concurrent mods to i_state */
476 inode->i_state = I_FREEING | I_CLEAR;
478 EXPORT_SYMBOL(end_writeback);
481 * Free the inode passed in, removing it from the lists it is still connected
482 * to. We remove any pages still attached to the inode and wait for any IO that
483 * is still in progress before finally destroying the inode.
485 * An inode must already be marked I_FREEING so that we avoid the inode being
486 * moved back onto lists if we race with other code that manipulates the lists
487 * (e.g. writeback_single_inode). The caller is responsible for setting this.
489 * An inode must already be removed from the LRU list before being evicted from
490 * the cache. This should occur atomically with setting the I_FREEING state
491 * flag, so no inodes here should ever be on the LRU when being evicted.
493 static void evict(struct inode *inode)
495 const struct super_operations *op = inode->i_sb->s_op;
497 BUG_ON(!(inode->i_state & I_FREEING));
498 BUG_ON(!list_empty(&inode->i_lru));
500 inode_wb_list_del(inode);
501 inode_sb_list_del(inode);
503 if (op->evict_inode) {
504 op->evict_inode(inode);
505 } else {
506 if (inode->i_data.nrpages)
507 truncate_inode_pages(&inode->i_data, 0);
508 end_writeback(inode);
510 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
511 bd_forget(inode);
512 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
513 cd_forget(inode);
515 remove_inode_hash(inode);
517 spin_lock(&inode->i_lock);
518 wake_up_bit(&inode->i_state, __I_NEW);
519 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
520 spin_unlock(&inode->i_lock);
522 destroy_inode(inode);
526 * dispose_list - dispose of the contents of a local list
527 * @head: the head of the list to free
529 * Dispose-list gets a local list with local inodes in it, so it doesn't
530 * need to worry about list corruption and SMP locks.
532 static void dispose_list(struct list_head *head)
534 while (!list_empty(head)) {
535 struct inode *inode;
537 inode = list_first_entry(head, struct inode, i_lru);
538 list_del_init(&inode->i_lru);
540 evict(inode);
545 * evict_inodes - evict all evictable inodes for a superblock
546 * @sb: superblock to operate on
548 * Make sure that no inodes with zero refcount are retained. This is
549 * called by superblock shutdown after having MS_ACTIVE flag removed,
550 * so any inode reaching zero refcount during or after that call will
551 * be immediately evicted.
553 void evict_inodes(struct super_block *sb)
555 struct inode *inode, *next;
556 LIST_HEAD(dispose);
558 spin_lock(&inode_sb_list_lock);
559 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
560 if (atomic_read(&inode->i_count))
561 continue;
563 spin_lock(&inode->i_lock);
564 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
565 spin_unlock(&inode->i_lock);
566 continue;
569 inode->i_state |= I_FREEING;
570 inode_lru_list_del(inode);
571 spin_unlock(&inode->i_lock);
572 list_add(&inode->i_lru, &dispose);
574 spin_unlock(&inode_sb_list_lock);
576 dispose_list(&dispose);
579 * Cycle through iprune_sem to make sure any inode that prune_icache
580 * moved off the list before we took the lock has been fully torn
581 * down.
583 down_write(&iprune_sem);
584 up_write(&iprune_sem);
588 * invalidate_inodes - attempt to free all inodes on a superblock
589 * @sb: superblock to operate on
590 * @kill_dirty: flag to guide handling of dirty inodes
592 * Attempts to free all inodes for a given superblock. If there were any
593 * busy inodes return a non-zero value, else zero.
594 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
595 * them as busy.
597 int invalidate_inodes(struct super_block *sb, bool kill_dirty)
599 int busy = 0;
600 struct inode *inode, *next;
601 LIST_HEAD(dispose);
603 spin_lock(&inode_sb_list_lock);
604 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
605 spin_lock(&inode->i_lock);
606 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
607 spin_unlock(&inode->i_lock);
608 continue;
610 if (inode->i_state & I_DIRTY && !kill_dirty) {
611 spin_unlock(&inode->i_lock);
612 busy = 1;
613 continue;
615 if (atomic_read(&inode->i_count)) {
616 spin_unlock(&inode->i_lock);
617 busy = 1;
618 continue;
621 inode->i_state |= I_FREEING;
622 inode_lru_list_del(inode);
623 spin_unlock(&inode->i_lock);
624 list_add(&inode->i_lru, &dispose);
626 spin_unlock(&inode_sb_list_lock);
628 dispose_list(&dispose);
630 return busy;
633 static int can_unuse(struct inode *inode)
635 if (inode->i_state & ~I_REFERENCED)
636 return 0;
637 if (inode_has_buffers(inode))
638 return 0;
639 if (atomic_read(&inode->i_count))
640 return 0;
641 if (inode->i_data.nrpages)
642 return 0;
643 return 1;
647 * Scan `goal' inodes on the unused list for freeable ones. They are moved to a
648 * temporary list and then are freed outside inode_lru_lock by dispose_list().
650 * Any inodes which are pinned purely because of attached pagecache have their
651 * pagecache removed. If the inode has metadata buffers attached to
652 * mapping->private_list then try to remove them.
654 * If the inode has the I_REFERENCED flag set, then it means that it has been
655 * used recently - the flag is set in iput_final(). When we encounter such an
656 * inode, clear the flag and move it to the back of the LRU so it gets another
657 * pass through the LRU before it gets reclaimed. This is necessary because of
658 * the fact we are doing lazy LRU updates to minimise lock contention so the
659 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
660 * with this flag set because they are the inodes that are out of order.
662 static void prune_icache(int nr_to_scan)
664 LIST_HEAD(freeable);
665 int nr_scanned;
666 unsigned long reap = 0;
668 down_read(&iprune_sem);
669 spin_lock(&inode_lru_lock);
670 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
671 struct inode *inode;
673 if (list_empty(&inode_lru))
674 break;
676 inode = list_entry(inode_lru.prev, struct inode, i_lru);
679 * we are inverting the inode_lru_lock/inode->i_lock here,
680 * so use a trylock. If we fail to get the lock, just move the
681 * inode to the back of the list so we don't spin on it.
683 if (!spin_trylock(&inode->i_lock)) {
684 list_move(&inode->i_lru, &inode_lru);
685 continue;
689 * Referenced or dirty inodes are still in use. Give them
690 * another pass through the LRU as we canot reclaim them now.
692 if (atomic_read(&inode->i_count) ||
693 (inode->i_state & ~I_REFERENCED)) {
694 list_del_init(&inode->i_lru);
695 spin_unlock(&inode->i_lock);
696 inodes_stat.nr_unused--;
697 continue;
700 /* recently referenced inodes get one more pass */
701 if (inode->i_state & I_REFERENCED) {
702 inode->i_state &= ~I_REFERENCED;
703 list_move(&inode->i_lru, &inode_lru);
704 spin_unlock(&inode->i_lock);
705 continue;
707 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
708 __iget(inode);
709 spin_unlock(&inode->i_lock);
710 spin_unlock(&inode_lru_lock);
711 if (remove_inode_buffers(inode))
712 reap += invalidate_mapping_pages(&inode->i_data,
713 0, -1);
714 iput(inode);
715 spin_lock(&inode_lru_lock);
717 if (inode != list_entry(inode_lru.next,
718 struct inode, i_lru))
719 continue; /* wrong inode or list_empty */
720 /* avoid lock inversions with trylock */
721 if (!spin_trylock(&inode->i_lock))
722 continue;
723 if (!can_unuse(inode)) {
724 spin_unlock(&inode->i_lock);
725 continue;
728 WARN_ON(inode->i_state & I_NEW);
729 inode->i_state |= I_FREEING;
730 spin_unlock(&inode->i_lock);
732 list_move(&inode->i_lru, &freeable);
733 inodes_stat.nr_unused--;
735 if (current_is_kswapd())
736 __count_vm_events(KSWAPD_INODESTEAL, reap);
737 else
738 __count_vm_events(PGINODESTEAL, reap);
739 spin_unlock(&inode_lru_lock);
741 dispose_list(&freeable);
742 up_read(&iprune_sem);
746 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
747 * "unused" means that no dentries are referring to the inodes: the files are
748 * not open and the dcache references to those inodes have already been
749 * reclaimed.
751 * This function is passed the number of inodes to scan, and it returns the
752 * total number of remaining possibly-reclaimable inodes.
754 static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
756 if (nr) {
758 * Nasty deadlock avoidance. We may hold various FS locks,
759 * and we don't want to recurse into the FS that called us
760 * in clear_inode() and friends..
762 if (!(gfp_mask & __GFP_FS))
763 return -1;
764 prune_icache(nr);
766 return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
769 static struct shrinker icache_shrinker = {
770 .shrink = shrink_icache_memory,
771 .seeks = DEFAULT_SEEKS,
774 static void __wait_on_freeing_inode(struct inode *inode);
776 * Called with the inode lock held.
778 static struct inode *find_inode(struct super_block *sb,
779 struct hlist_head *head,
780 int (*test)(struct inode *, void *),
781 void *data)
783 struct hlist_node *node;
784 struct inode *inode = NULL;
786 repeat:
787 hlist_for_each_entry(inode, node, head, i_hash) {
788 spin_lock(&inode->i_lock);
789 if (inode->i_sb != sb) {
790 spin_unlock(&inode->i_lock);
791 continue;
793 if (!test(inode, data)) {
794 spin_unlock(&inode->i_lock);
795 continue;
797 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
798 __wait_on_freeing_inode(inode);
799 goto repeat;
801 __iget(inode);
802 spin_unlock(&inode->i_lock);
803 return inode;
805 return NULL;
809 * find_inode_fast is the fast path version of find_inode, see the comment at
810 * iget_locked for details.
812 static struct inode *find_inode_fast(struct super_block *sb,
813 struct hlist_head *head, unsigned long ino)
815 struct hlist_node *node;
816 struct inode *inode = NULL;
818 repeat:
819 hlist_for_each_entry(inode, node, head, i_hash) {
820 spin_lock(&inode->i_lock);
821 if (inode->i_ino != ino) {
822 spin_unlock(&inode->i_lock);
823 continue;
825 if (inode->i_sb != sb) {
826 spin_unlock(&inode->i_lock);
827 continue;
829 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
830 __wait_on_freeing_inode(inode);
831 goto repeat;
833 __iget(inode);
834 spin_unlock(&inode->i_lock);
835 return inode;
837 return NULL;
841 * Each cpu owns a range of LAST_INO_BATCH numbers.
842 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
843 * to renew the exhausted range.
845 * This does not significantly increase overflow rate because every CPU can
846 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
847 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
848 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
849 * overflow rate by 2x, which does not seem too significant.
851 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
852 * error if st_ino won't fit in target struct field. Use 32bit counter
853 * here to attempt to avoid that.
855 #define LAST_INO_BATCH 1024
856 static DEFINE_PER_CPU(unsigned int, last_ino);
858 unsigned int get_next_ino(void)
860 unsigned int *p = &get_cpu_var(last_ino);
861 unsigned int res = *p;
863 #ifdef CONFIG_SMP
864 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
865 static atomic_t shared_last_ino;
866 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
868 res = next - LAST_INO_BATCH;
870 #endif
872 *p = ++res;
873 put_cpu_var(last_ino);
874 return res;
876 EXPORT_SYMBOL(get_next_ino);
879 * new_inode - obtain an inode
880 * @sb: superblock
882 * Allocates a new inode for given superblock. The default gfp_mask
883 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
884 * If HIGHMEM pages are unsuitable or it is known that pages allocated
885 * for the page cache are not reclaimable or migratable,
886 * mapping_set_gfp_mask() must be called with suitable flags on the
887 * newly created inode's mapping
890 struct inode *new_inode(struct super_block *sb)
892 struct inode *inode;
894 spin_lock_prefetch(&inode_sb_list_lock);
896 inode = alloc_inode(sb);
897 if (inode) {
898 spin_lock(&inode->i_lock);
899 inode->i_state = 0;
900 spin_unlock(&inode->i_lock);
901 inode_sb_list_add(inode);
903 return inode;
905 EXPORT_SYMBOL(new_inode);
908 * unlock_new_inode - clear the I_NEW state and wake up any waiters
909 * @inode: new inode to unlock
911 * Called when the inode is fully initialised to clear the new state of the
912 * inode and wake up anyone waiting for the inode to finish initialisation.
914 void unlock_new_inode(struct inode *inode)
916 #ifdef CONFIG_DEBUG_LOCK_ALLOC
917 if (S_ISDIR(inode->i_mode)) {
918 struct file_system_type *type = inode->i_sb->s_type;
920 /* Set new key only if filesystem hasn't already changed it */
921 if (!lockdep_match_class(&inode->i_mutex,
922 &type->i_mutex_key)) {
924 * ensure nobody is actually holding i_mutex
926 mutex_destroy(&inode->i_mutex);
927 mutex_init(&inode->i_mutex);
928 lockdep_set_class(&inode->i_mutex,
929 &type->i_mutex_dir_key);
932 #endif
933 spin_lock(&inode->i_lock);
934 WARN_ON(!(inode->i_state & I_NEW));
935 inode->i_state &= ~I_NEW;
936 wake_up_bit(&inode->i_state, __I_NEW);
937 spin_unlock(&inode->i_lock);
939 EXPORT_SYMBOL(unlock_new_inode);
942 * iget5_locked - obtain an inode from a mounted file system
943 * @sb: super block of file system
944 * @hashval: hash value (usually inode number) to get
945 * @test: callback used for comparisons between inodes
946 * @set: callback used to initialize a new struct inode
947 * @data: opaque data pointer to pass to @test and @set
949 * Search for the inode specified by @hashval and @data in the inode cache,
950 * and if present it is return it with an increased reference count. This is
951 * a generalized version of iget_locked() for file systems where the inode
952 * number is not sufficient for unique identification of an inode.
954 * If the inode is not in cache, allocate a new inode and return it locked,
955 * hashed, and with the I_NEW flag set. The file system gets to fill it in
956 * before unlocking it via unlock_new_inode().
958 * Note both @test and @set are called with the inode_hash_lock held, so can't
959 * sleep.
961 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
962 int (*test)(struct inode *, void *),
963 int (*set)(struct inode *, void *), void *data)
965 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
966 struct inode *inode;
968 spin_lock(&inode_hash_lock);
969 inode = find_inode(sb, head, test, data);
970 spin_unlock(&inode_hash_lock);
972 if (inode) {
973 wait_on_inode(inode);
974 return inode;
977 inode = alloc_inode(sb);
978 if (inode) {
979 struct inode *old;
981 spin_lock(&inode_hash_lock);
982 /* We released the lock, so.. */
983 old = find_inode(sb, head, test, data);
984 if (!old) {
985 if (set(inode, data))
986 goto set_failed;
988 spin_lock(&inode->i_lock);
989 inode->i_state = I_NEW;
990 hlist_add_head(&inode->i_hash, head);
991 spin_unlock(&inode->i_lock);
992 inode_sb_list_add(inode);
993 spin_unlock(&inode_hash_lock);
995 /* Return the locked inode with I_NEW set, the
996 * caller is responsible for filling in the contents
998 return inode;
1002 * Uhhuh, somebody else created the same inode under
1003 * us. Use the old inode instead of the one we just
1004 * allocated.
1006 spin_unlock(&inode_hash_lock);
1007 destroy_inode(inode);
1008 inode = old;
1009 wait_on_inode(inode);
1011 return inode;
1013 set_failed:
1014 spin_unlock(&inode_hash_lock);
1015 destroy_inode(inode);
1016 return NULL;
1018 EXPORT_SYMBOL(iget5_locked);
1021 * iget_locked - obtain an inode from a mounted file system
1022 * @sb: super block of file system
1023 * @ino: inode number to get
1025 * Search for the inode specified by @ino in the inode cache and if present
1026 * return it with an increased reference count. This is for file systems
1027 * where the inode number is sufficient for unique identification of an inode.
1029 * If the inode is not in cache, allocate a new inode and return it locked,
1030 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1031 * before unlocking it via unlock_new_inode().
1033 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1035 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1036 struct inode *inode;
1038 spin_lock(&inode_hash_lock);
1039 inode = find_inode_fast(sb, head, ino);
1040 spin_unlock(&inode_hash_lock);
1041 if (inode) {
1042 wait_on_inode(inode);
1043 return inode;
1046 inode = alloc_inode(sb);
1047 if (inode) {
1048 struct inode *old;
1050 spin_lock(&inode_hash_lock);
1051 /* We released the lock, so.. */
1052 old = find_inode_fast(sb, head, ino);
1053 if (!old) {
1054 inode->i_ino = ino;
1055 spin_lock(&inode->i_lock);
1056 inode->i_state = I_NEW;
1057 hlist_add_head(&inode->i_hash, head);
1058 spin_unlock(&inode->i_lock);
1059 inode_sb_list_add(inode);
1060 spin_unlock(&inode_hash_lock);
1062 /* Return the locked inode with I_NEW set, the
1063 * caller is responsible for filling in the contents
1065 return inode;
1069 * Uhhuh, somebody else created the same inode under
1070 * us. Use the old inode instead of the one we just
1071 * allocated.
1073 spin_unlock(&inode_hash_lock);
1074 destroy_inode(inode);
1075 inode = old;
1076 wait_on_inode(inode);
1078 return inode;
1080 EXPORT_SYMBOL(iget_locked);
1083 * search the inode cache for a matching inode number.
1084 * If we find one, then the inode number we are trying to
1085 * allocate is not unique and so we should not use it.
1087 * Returns 1 if the inode number is unique, 0 if it is not.
1089 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1091 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1092 struct hlist_node *node;
1093 struct inode *inode;
1095 spin_lock(&inode_hash_lock);
1096 hlist_for_each_entry(inode, node, b, i_hash) {
1097 if (inode->i_ino == ino && inode->i_sb == sb) {
1098 spin_unlock(&inode_hash_lock);
1099 return 0;
1102 spin_unlock(&inode_hash_lock);
1104 return 1;
1108 * iunique - get a unique inode number
1109 * @sb: superblock
1110 * @max_reserved: highest reserved inode number
1112 * Obtain an inode number that is unique on the system for a given
1113 * superblock. This is used by file systems that have no natural
1114 * permanent inode numbering system. An inode number is returned that
1115 * is higher than the reserved limit but unique.
1117 * BUGS:
1118 * With a large number of inodes live on the file system this function
1119 * currently becomes quite slow.
1121 ino_t iunique(struct super_block *sb, ino_t max_reserved)
1124 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1125 * error if st_ino won't fit in target struct field. Use 32bit counter
1126 * here to attempt to avoid that.
1128 static DEFINE_SPINLOCK(iunique_lock);
1129 static unsigned int counter;
1130 ino_t res;
1132 spin_lock(&iunique_lock);
1133 do {
1134 if (counter <= max_reserved)
1135 counter = max_reserved + 1;
1136 res = counter++;
1137 } while (!test_inode_iunique(sb, res));
1138 spin_unlock(&iunique_lock);
1140 return res;
1142 EXPORT_SYMBOL(iunique);
1144 struct inode *igrab(struct inode *inode)
1146 spin_lock(&inode->i_lock);
1147 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1148 __iget(inode);
1149 spin_unlock(&inode->i_lock);
1150 } else {
1151 spin_unlock(&inode->i_lock);
1153 * Handle the case where s_op->clear_inode is not been
1154 * called yet, and somebody is calling igrab
1155 * while the inode is getting freed.
1157 inode = NULL;
1159 return inode;
1161 EXPORT_SYMBOL(igrab);
1164 * ilookup5_nowait - search for an inode in the inode cache
1165 * @sb: super block of file system to search
1166 * @hashval: hash value (usually inode number) to search for
1167 * @test: callback used for comparisons between inodes
1168 * @data: opaque data pointer to pass to @test
1170 * Search for the inode specified by @hashval and @data in the inode cache.
1171 * If the inode is in the cache, the inode is returned with an incremented
1172 * reference count.
1174 * Note: I_NEW is not waited upon so you have to be very careful what you do
1175 * with the returned inode. You probably should be using ilookup5() instead.
1177 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1179 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1180 int (*test)(struct inode *, void *), void *data)
1182 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1183 struct inode *inode;
1185 spin_lock(&inode_hash_lock);
1186 inode = find_inode(sb, head, test, data);
1187 spin_unlock(&inode_hash_lock);
1189 return inode;
1191 EXPORT_SYMBOL(ilookup5_nowait);
1194 * ilookup5 - search for an inode in the inode cache
1195 * @sb: super block of file system to search
1196 * @hashval: hash value (usually inode number) to search for
1197 * @test: callback used for comparisons between inodes
1198 * @data: opaque data pointer to pass to @test
1200 * Search for the inode specified by @hashval and @data in the inode cache,
1201 * and if the inode is in the cache, return the inode with an incremented
1202 * reference count. Waits on I_NEW before returning the inode.
1203 * returned with an incremented reference count.
1205 * This is a generalized version of ilookup() for file systems where the
1206 * inode number is not sufficient for unique identification of an inode.
1208 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1210 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1211 int (*test)(struct inode *, void *), void *data)
1213 struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
1215 if (inode)
1216 wait_on_inode(inode);
1217 return inode;
1219 EXPORT_SYMBOL(ilookup5);
1222 * ilookup - search for an inode in the inode cache
1223 * @sb: super block of file system to search
1224 * @ino: inode number to search for
1226 * Search for the inode @ino in the inode cache, and if the inode is in the
1227 * cache, the inode is returned with an incremented reference count.
1229 struct inode *ilookup(struct super_block *sb, unsigned long ino)
1231 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1232 struct inode *inode;
1234 spin_lock(&inode_hash_lock);
1235 inode = find_inode_fast(sb, head, ino);
1236 spin_unlock(&inode_hash_lock);
1238 if (inode)
1239 wait_on_inode(inode);
1240 return inode;
1242 EXPORT_SYMBOL(ilookup);
1244 int insert_inode_locked(struct inode *inode)
1246 struct super_block *sb = inode->i_sb;
1247 ino_t ino = inode->i_ino;
1248 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1250 while (1) {
1251 struct hlist_node *node;
1252 struct inode *old = NULL;
1253 spin_lock(&inode_hash_lock);
1254 hlist_for_each_entry(old, node, head, i_hash) {
1255 if (old->i_ino != ino)
1256 continue;
1257 if (old->i_sb != sb)
1258 continue;
1259 spin_lock(&old->i_lock);
1260 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1261 spin_unlock(&old->i_lock);
1262 continue;
1264 break;
1266 if (likely(!node)) {
1267 spin_lock(&inode->i_lock);
1268 inode->i_state |= I_NEW;
1269 hlist_add_head(&inode->i_hash, head);
1270 spin_unlock(&inode->i_lock);
1271 spin_unlock(&inode_hash_lock);
1272 return 0;
1274 __iget(old);
1275 spin_unlock(&old->i_lock);
1276 spin_unlock(&inode_hash_lock);
1277 wait_on_inode(old);
1278 if (unlikely(!inode_unhashed(old))) {
1279 iput(old);
1280 return -EBUSY;
1282 iput(old);
1285 EXPORT_SYMBOL(insert_inode_locked);
1287 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1288 int (*test)(struct inode *, void *), void *data)
1290 struct super_block *sb = inode->i_sb;
1291 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1293 while (1) {
1294 struct hlist_node *node;
1295 struct inode *old = NULL;
1297 spin_lock(&inode_hash_lock);
1298 hlist_for_each_entry(old, node, head, i_hash) {
1299 if (old->i_sb != sb)
1300 continue;
1301 if (!test(old, data))
1302 continue;
1303 spin_lock(&old->i_lock);
1304 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1305 spin_unlock(&old->i_lock);
1306 continue;
1308 break;
1310 if (likely(!node)) {
1311 spin_lock(&inode->i_lock);
1312 inode->i_state |= I_NEW;
1313 hlist_add_head(&inode->i_hash, head);
1314 spin_unlock(&inode->i_lock);
1315 spin_unlock(&inode_hash_lock);
1316 return 0;
1318 __iget(old);
1319 spin_unlock(&old->i_lock);
1320 spin_unlock(&inode_hash_lock);
1321 wait_on_inode(old);
1322 if (unlikely(!inode_unhashed(old))) {
1323 iput(old);
1324 return -EBUSY;
1326 iput(old);
1329 EXPORT_SYMBOL(insert_inode_locked4);
1332 int generic_delete_inode(struct inode *inode)
1334 return 1;
1336 EXPORT_SYMBOL(generic_delete_inode);
1339 * Normal UNIX filesystem behaviour: delete the
1340 * inode when the usage count drops to zero, and
1341 * i_nlink is zero.
1343 int generic_drop_inode(struct inode *inode)
1345 return !inode->i_nlink || inode_unhashed(inode);
1347 EXPORT_SYMBOL_GPL(generic_drop_inode);
1350 * Called when we're dropping the last reference
1351 * to an inode.
1353 * Call the FS "drop_inode()" function, defaulting to
1354 * the legacy UNIX filesystem behaviour. If it tells
1355 * us to evict inode, do so. Otherwise, retain inode
1356 * in cache if fs is alive, sync and evict if fs is
1357 * shutting down.
1359 static void iput_final(struct inode *inode)
1361 struct super_block *sb = inode->i_sb;
1362 const struct super_operations *op = inode->i_sb->s_op;
1363 int drop;
1365 WARN_ON(inode->i_state & I_NEW);
1367 if (op && op->drop_inode)
1368 drop = op->drop_inode(inode);
1369 else
1370 drop = generic_drop_inode(inode);
1372 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1373 inode->i_state |= I_REFERENCED;
1374 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
1375 inode_lru_list_add(inode);
1376 spin_unlock(&inode->i_lock);
1377 return;
1380 if (!drop) {
1381 inode->i_state |= I_WILL_FREE;
1382 spin_unlock(&inode->i_lock);
1383 write_inode_now(inode, 1);
1384 spin_lock(&inode->i_lock);
1385 WARN_ON(inode->i_state & I_NEW);
1386 inode->i_state &= ~I_WILL_FREE;
1389 inode->i_state |= I_FREEING;
1390 inode_lru_list_del(inode);
1391 spin_unlock(&inode->i_lock);
1393 evict(inode);
1397 * iput - put an inode
1398 * @inode: inode to put
1400 * Puts an inode, dropping its usage count. If the inode use count hits
1401 * zero, the inode is then freed and may also be destroyed.
1403 * Consequently, iput() can sleep.
1405 void iput(struct inode *inode)
1407 if (inode) {
1408 BUG_ON(inode->i_state & I_CLEAR);
1410 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
1411 iput_final(inode);
1414 EXPORT_SYMBOL(iput);
1417 * bmap - find a block number in a file
1418 * @inode: inode of file
1419 * @block: block to find
1421 * Returns the block number on the device holding the inode that
1422 * is the disk block number for the block of the file requested.
1423 * That is, asked for block 4 of inode 1 the function will return the
1424 * disk block relative to the disk start that holds that block of the
1425 * file.
1427 sector_t bmap(struct inode *inode, sector_t block)
1429 sector_t res = 0;
1430 if (inode->i_mapping->a_ops->bmap)
1431 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1432 return res;
1434 EXPORT_SYMBOL(bmap);
1437 * With relative atime, only update atime if the previous atime is
1438 * earlier than either the ctime or mtime or if at least a day has
1439 * passed since the last atime update.
1441 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1442 struct timespec now)
1445 if (!(mnt->mnt_flags & MNT_RELATIME))
1446 return 1;
1448 * Is mtime younger than atime? If yes, update atime:
1450 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1451 return 1;
1453 * Is ctime younger than atime? If yes, update atime:
1455 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1456 return 1;
1459 * Is the previous atime value older than a day? If yes,
1460 * update atime:
1462 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1463 return 1;
1465 * Good, we can skip the atime update:
1467 return 0;
1471 * touch_atime - update the access time
1472 * @mnt: mount the inode is accessed on
1473 * @dentry: dentry accessed
1475 * Update the accessed time on an inode and mark it for writeback.
1476 * This function automatically handles read only file systems and media,
1477 * as well as the "noatime" flag and inode specific "noatime" markers.
1479 void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1481 struct inode *inode = dentry->d_inode;
1482 struct timespec now;
1484 if (inode->i_flags & S_NOATIME)
1485 return;
1486 if (IS_NOATIME(inode))
1487 return;
1488 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1489 return;
1491 if (mnt->mnt_flags & MNT_NOATIME)
1492 return;
1493 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1494 return;
1496 now = current_fs_time(inode->i_sb);
1498 if (!relatime_need_update(mnt, inode, now))
1499 return;
1501 if (timespec_equal(&inode->i_atime, &now))
1502 return;
1504 if (mnt_want_write(mnt))
1505 return;
1507 inode->i_atime = now;
1508 mark_inode_dirty_sync(inode);
1509 mnt_drop_write(mnt);
1511 EXPORT_SYMBOL(touch_atime);
1514 * file_update_time - update mtime and ctime time
1515 * @file: file accessed
1517 * Update the mtime and ctime members of an inode and mark the inode
1518 * for writeback. Note that this function is meant exclusively for
1519 * usage in the file write path of filesystems, and filesystems may
1520 * choose to explicitly ignore update via this function with the
1521 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1522 * timestamps are handled by the server.
1525 void file_update_time(struct file *file)
1527 struct inode *inode = file->f_path.dentry->d_inode;
1528 struct timespec now;
1529 enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
1531 /* First try to exhaust all avenues to not sync */
1532 if (IS_NOCMTIME(inode))
1533 return;
1535 now = current_fs_time(inode->i_sb);
1536 if (!timespec_equal(&inode->i_mtime, &now))
1537 sync_it = S_MTIME;
1539 if (!timespec_equal(&inode->i_ctime, &now))
1540 sync_it |= S_CTIME;
1542 if (IS_I_VERSION(inode))
1543 sync_it |= S_VERSION;
1545 if (!sync_it)
1546 return;
1548 /* Finally allowed to write? Takes lock. */
1549 if (mnt_want_write_file(file))
1550 return;
1552 /* Only change inode inside the lock region */
1553 if (sync_it & S_VERSION)
1554 inode_inc_iversion(inode);
1555 if (sync_it & S_CTIME)
1556 inode->i_ctime = now;
1557 if (sync_it & S_MTIME)
1558 inode->i_mtime = now;
1559 mark_inode_dirty_sync(inode);
1560 mnt_drop_write(file->f_path.mnt);
1562 EXPORT_SYMBOL(file_update_time);
1564 int inode_needs_sync(struct inode *inode)
1566 if (IS_SYNC(inode))
1567 return 1;
1568 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1569 return 1;
1570 return 0;
1572 EXPORT_SYMBOL(inode_needs_sync);
1574 int inode_wait(void *word)
1576 schedule();
1577 return 0;
1579 EXPORT_SYMBOL(inode_wait);
1582 * If we try to find an inode in the inode hash while it is being
1583 * deleted, we have to wait until the filesystem completes its
1584 * deletion before reporting that it isn't found. This function waits
1585 * until the deletion _might_ have completed. Callers are responsible
1586 * to recheck inode state.
1588 * It doesn't matter if I_NEW is not set initially, a call to
1589 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1590 * will DTRT.
1592 static void __wait_on_freeing_inode(struct inode *inode)
1594 wait_queue_head_t *wq;
1595 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1596 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1597 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1598 spin_unlock(&inode->i_lock);
1599 spin_unlock(&inode_hash_lock);
1600 schedule();
1601 finish_wait(wq, &wait.wait);
1602 spin_lock(&inode_hash_lock);
1605 static __initdata unsigned long ihash_entries;
1606 static int __init set_ihash_entries(char *str)
1608 if (!str)
1609 return 0;
1610 ihash_entries = simple_strtoul(str, &str, 0);
1611 return 1;
1613 __setup("ihash_entries=", set_ihash_entries);
1616 * Initialize the waitqueues and inode hash table.
1618 void __init inode_init_early(void)
1620 int loop;
1622 /* If hashes are distributed across NUMA nodes, defer
1623 * hash allocation until vmalloc space is available.
1625 if (hashdist)
1626 return;
1628 inode_hashtable =
1629 alloc_large_system_hash("Inode-cache",
1630 sizeof(struct hlist_head),
1631 ihash_entries,
1633 HASH_EARLY,
1634 &i_hash_shift,
1635 &i_hash_mask,
1638 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1639 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1642 void __init inode_init(void)
1644 int loop;
1646 /* inode slab cache */
1647 inode_cachep = kmem_cache_create("inode_cache",
1648 sizeof(struct inode),
1650 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1651 SLAB_MEM_SPREAD),
1652 init_once);
1653 register_shrinker(&icache_shrinker);
1655 /* Hash may have been set up in inode_init_early */
1656 if (!hashdist)
1657 return;
1659 inode_hashtable =
1660 alloc_large_system_hash("Inode-cache",
1661 sizeof(struct hlist_head),
1662 ihash_entries,
1665 &i_hash_shift,
1666 &i_hash_mask,
1669 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1670 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1673 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1675 inode->i_mode = mode;
1676 if (S_ISCHR(mode)) {
1677 inode->i_fop = &def_chr_fops;
1678 inode->i_rdev = rdev;
1679 } else if (S_ISBLK(mode)) {
1680 inode->i_fop = &def_blk_fops;
1681 inode->i_rdev = rdev;
1682 } else if (S_ISFIFO(mode))
1683 inode->i_fop = &def_fifo_fops;
1684 else if (S_ISSOCK(mode))
1685 inode->i_fop = &bad_sock_fops;
1686 else
1687 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1688 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1689 inode->i_ino);
1691 EXPORT_SYMBOL(init_special_inode);
1694 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1695 * @inode: New inode
1696 * @dir: Directory inode
1697 * @mode: mode of the new inode
1699 void inode_init_owner(struct inode *inode, const struct inode *dir,
1700 mode_t mode)
1702 inode->i_uid = current_fsuid();
1703 if (dir && dir->i_mode & S_ISGID) {
1704 inode->i_gid = dir->i_gid;
1705 if (S_ISDIR(mode))
1706 mode |= S_ISGID;
1707 } else
1708 inode->i_gid = current_fsgid();
1709 inode->i_mode = mode;
1711 EXPORT_SYMBOL(inode_init_owner);
1714 * inode_owner_or_capable - check current task permissions to inode
1715 * @inode: inode being checked
1717 * Return true if current either has CAP_FOWNER to the inode, or
1718 * owns the file.
1720 bool inode_owner_or_capable(const struct inode *inode)
1722 struct user_namespace *ns = inode_userns(inode);
1724 if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
1725 return true;
1726 if (ns_capable(ns, CAP_FOWNER))
1727 return true;
1728 return false;
1730 EXPORT_SYMBOL(inode_owner_or_capable);