4 * (C) 1997 Linus Torvalds
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>
23 #include <linux/inotify.h>
24 #include <linux/mount.h>
27 * This is needed for the following functions:
29 * - invalidate_inode_buffers
32 * FIXME: remove all knowledge of the buffer layer from this file
34 #include <linux/buffer_head.h>
37 * New inode.c implementation.
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".
46 /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
48 /* #define INODE_PARANOIA 1 */
49 /* #define INODE_DEBUG 1 */
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.
55 #define I_HASHBITS i_hash_shift
56 #define I_HASHMASK i_hash_mask
58 static unsigned int i_hash_mask __read_mostly;
59 static unsigned int i_hash_shift __read_mostly;
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
69 * A "dirty" list is maintained for each super block,
70 * allowing for low-overhead inode sync() operations.
73 LIST_HEAD(inode_in_use);
74 LIST_HEAD(inode_unused);
75 static struct hlist_head *inode_hashtable __read_mostly;
78 * A simple spinlock to protect the list manipulations.
80 * NOTE! You also have to own the lock if you change
81 * the i_state of an inode while it is in use..
83 DEFINE_SPINLOCK(inode_lock);
86 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
87 * 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.
93 static DEFINE_MUTEX(iprune_mutex);
96 * Statistics gathering..
98 struct inodes_stat_t inodes_stat;
100 static struct kmem_cache * inode_cachep __read_mostly;
102 static void wake_up_inode(struct inode *inode)
105 * Prevent speculative execution through spin_unlock(&inode_lock);
108 wake_up_bit(&inode->i_state, __I_LOCK);
111 static struct inode *alloc_inode(struct super_block *sb)
113 static const struct address_space_operations empty_aops;
114 static struct inode_operations empty_iops;
115 static const struct file_operations empty_fops;
118 if (sb->s_op->alloc_inode)
119 inode = sb->s_op->alloc_inode(sb);
121 inode = (struct inode *) kmem_cache_alloc(inode_cachep, GFP_KERNEL);
124 struct address_space * const mapping = &inode->i_data;
127 inode->i_blkbits = sb->s_blocksize_bits;
129 atomic_set(&inode->i_count, 1);
130 inode->i_op = &empty_iops;
131 inode->i_fop = &empty_fops;
133 atomic_set(&inode->i_writecount, 0);
137 inode->i_generation = 0;
139 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
141 inode->i_pipe = NULL;
142 inode->i_bdev = NULL;
143 inode->i_cdev = NULL;
145 inode->dirtied_when = 0;
146 if (security_inode_alloc(inode)) {
147 if (inode->i_sb->s_op->destroy_inode)
148 inode->i_sb->s_op->destroy_inode(inode);
150 kmem_cache_free(inode_cachep, (inode));
154 spin_lock_init(&inode->i_lock);
155 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
157 mutex_init(&inode->i_mutex);
158 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
160 init_rwsem(&inode->i_alloc_sem);
161 lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
163 mapping->a_ops = &empty_aops;
164 mapping->host = inode;
166 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
167 mapping->assoc_mapping = NULL;
168 mapping->backing_dev_info = &default_backing_dev_info;
171 * If the block_device provides a backing_dev_info for client
172 * inodes then use that. Otherwise the inode share the bdev's
176 struct backing_dev_info *bdi;
178 bdi = sb->s_bdev->bd_inode_backing_dev_info;
180 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
181 mapping->backing_dev_info = bdi;
183 inode->i_private = NULL;
184 inode->i_mapping = mapping;
189 void destroy_inode(struct inode *inode)
191 BUG_ON(inode_has_buffers(inode));
192 security_inode_free(inode);
193 if (inode->i_sb->s_op->destroy_inode)
194 inode->i_sb->s_op->destroy_inode(inode);
196 kmem_cache_free(inode_cachep, (inode));
201 * These are initializations that only need to be done
202 * once, because the fields are idempotent across use
203 * of the inode, so let the slab aware of that.
205 void inode_init_once(struct inode *inode)
207 memset(inode, 0, sizeof(*inode));
208 INIT_HLIST_NODE(&inode->i_hash);
209 INIT_LIST_HEAD(&inode->i_dentry);
210 INIT_LIST_HEAD(&inode->i_devices);
211 INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
212 rwlock_init(&inode->i_data.tree_lock);
213 spin_lock_init(&inode->i_data.i_mmap_lock);
214 INIT_LIST_HEAD(&inode->i_data.private_list);
215 spin_lock_init(&inode->i_data.private_lock);
216 INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
217 INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
218 i_size_ordered_init(inode);
219 #ifdef CONFIG_INOTIFY
220 INIT_LIST_HEAD(&inode->inotify_watches);
221 mutex_init(&inode->inotify_mutex);
225 EXPORT_SYMBOL(inode_init_once);
227 static void init_once(struct kmem_cache * cachep, void *foo)
229 struct inode * inode = (struct inode *) foo;
231 inode_init_once(inode);
235 * inode_lock must be held
237 void __iget(struct inode * inode)
239 if (atomic_read(&inode->i_count)) {
240 atomic_inc(&inode->i_count);
243 atomic_inc(&inode->i_count);
244 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
245 list_move(&inode->i_list, &inode_in_use);
246 inodes_stat.nr_unused--;
250 * clear_inode - clear an inode
251 * @inode: inode to clear
253 * This is called by the filesystem to tell us
254 * that the inode is no longer useful. We just
255 * terminate it with extreme prejudice.
257 void clear_inode(struct inode *inode)
260 invalidate_inode_buffers(inode);
262 BUG_ON(inode->i_data.nrpages);
263 BUG_ON(!(inode->i_state & I_FREEING));
264 BUG_ON(inode->i_state & I_CLEAR);
265 inode_sync_wait(inode);
267 if (inode->i_sb->s_op->clear_inode)
268 inode->i_sb->s_op->clear_inode(inode);
269 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
271 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
273 inode->i_state = I_CLEAR;
276 EXPORT_SYMBOL(clear_inode);
279 * dispose_list - dispose of the contents of a local list
280 * @head: the head of the list to free
282 * Dispose-list gets a local list with local inodes in it, so it doesn't
283 * need to worry about list corruption and SMP locks.
285 static void dispose_list(struct list_head *head)
289 while (!list_empty(head)) {
292 inode = list_first_entry(head, struct inode, i_list);
293 list_del(&inode->i_list);
295 if (inode->i_data.nrpages)
296 truncate_inode_pages(&inode->i_data, 0);
299 spin_lock(&inode_lock);
300 hlist_del_init(&inode->i_hash);
301 list_del_init(&inode->i_sb_list);
302 spin_unlock(&inode_lock);
304 wake_up_inode(inode);
305 destroy_inode(inode);
308 spin_lock(&inode_lock);
309 inodes_stat.nr_inodes -= nr_disposed;
310 spin_unlock(&inode_lock);
314 * Invalidate all inodes for a device.
316 static int invalidate_list(struct list_head *head, struct list_head *dispose)
318 struct list_head *next;
319 int busy = 0, count = 0;
323 struct list_head * tmp = next;
324 struct inode * inode;
327 * We can reschedule here without worrying about the list's
328 * consistency because the per-sb list of inodes must not
329 * change during umount anymore, and because iprune_mutex keeps
330 * shrink_icache_memory() away.
332 cond_resched_lock(&inode_lock);
337 inode = list_entry(tmp, struct inode, i_sb_list);
338 invalidate_inode_buffers(inode);
339 if (!atomic_read(&inode->i_count)) {
340 list_move(&inode->i_list, dispose);
341 inode->i_state |= I_FREEING;
347 /* only unused inodes may be cached with i_count zero */
348 inodes_stat.nr_unused -= count;
353 * invalidate_inodes - discard the inodes on a device
356 * Discard all of the inodes for a given superblock. If the discard
357 * fails because there are busy inodes then a non zero value is returned.
358 * If the discard is successful all the inodes have been discarded.
360 int invalidate_inodes(struct super_block * sb)
363 LIST_HEAD(throw_away);
365 mutex_lock(&iprune_mutex);
366 spin_lock(&inode_lock);
367 inotify_unmount_inodes(&sb->s_inodes);
368 busy = invalidate_list(&sb->s_inodes, &throw_away);
369 spin_unlock(&inode_lock);
371 dispose_list(&throw_away);
372 mutex_unlock(&iprune_mutex);
377 EXPORT_SYMBOL(invalidate_inodes);
379 static int can_unuse(struct inode *inode)
383 if (inode_has_buffers(inode))
385 if (atomic_read(&inode->i_count))
387 if (inode->i_data.nrpages)
393 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
394 * a temporary list and then are freed outside inode_lock by dispose_list().
396 * Any inodes which are pinned purely because of attached pagecache have their
397 * pagecache removed. We expect the final iput() on that inode to add it to
398 * the front of the inode_unused list. So look for it there and if the
399 * inode is still freeable, proceed. The right inode is found 99.9% of the
400 * time in testing on a 4-way.
402 * If the inode has metadata buffers attached to mapping->private_list then
403 * try to remove them.
405 static void prune_icache(int nr_to_scan)
410 unsigned long reap = 0;
412 mutex_lock(&iprune_mutex);
413 spin_lock(&inode_lock);
414 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
417 if (list_empty(&inode_unused))
420 inode = list_entry(inode_unused.prev, struct inode, i_list);
422 if (inode->i_state || atomic_read(&inode->i_count)) {
423 list_move(&inode->i_list, &inode_unused);
426 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
428 spin_unlock(&inode_lock);
429 if (remove_inode_buffers(inode))
430 reap += invalidate_mapping_pages(&inode->i_data,
433 spin_lock(&inode_lock);
435 if (inode != list_entry(inode_unused.next,
436 struct inode, i_list))
437 continue; /* wrong inode or list_empty */
438 if (!can_unuse(inode))
441 list_move(&inode->i_list, &freeable);
442 inode->i_state |= I_FREEING;
445 inodes_stat.nr_unused -= nr_pruned;
446 if (current_is_kswapd())
447 __count_vm_events(KSWAPD_INODESTEAL, reap);
449 __count_vm_events(PGINODESTEAL, reap);
450 spin_unlock(&inode_lock);
452 dispose_list(&freeable);
453 mutex_unlock(&iprune_mutex);
457 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
458 * "unused" means that no dentries are referring to the inodes: the files are
459 * not open and the dcache references to those inodes have already been
462 * This function is passed the number of inodes to scan, and it returns the
463 * total number of remaining possibly-reclaimable inodes.
465 static int shrink_icache_memory(int nr, gfp_t gfp_mask)
469 * Nasty deadlock avoidance. We may hold various FS locks,
470 * and we don't want to recurse into the FS that called us
471 * in clear_inode() and friends..
473 if (!(gfp_mask & __GFP_FS))
477 return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
480 static struct shrinker icache_shrinker = {
481 .shrink = shrink_icache_memory,
482 .seeks = DEFAULT_SEEKS,
485 static void __wait_on_freeing_inode(struct inode *inode);
487 * Called with the inode lock held.
488 * NOTE: we are not increasing the inode-refcount, you must call __iget()
489 * by hand after calling find_inode now! This simplifies iunique and won't
490 * add any additional branch in the common code.
492 static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
494 struct hlist_node *node;
495 struct inode * inode = NULL;
498 hlist_for_each (node, head) {
499 inode = hlist_entry(node, struct inode, i_hash);
500 if (inode->i_sb != sb)
502 if (!test(inode, data))
504 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
505 __wait_on_freeing_inode(inode);
510 return node ? inode : NULL;
514 * find_inode_fast is the fast path version of find_inode, see the comment at
515 * iget_locked for details.
517 static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
519 struct hlist_node *node;
520 struct inode * inode = NULL;
523 hlist_for_each (node, head) {
524 inode = hlist_entry(node, struct inode, i_hash);
525 if (inode->i_ino != ino)
527 if (inode->i_sb != sb)
529 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
530 __wait_on_freeing_inode(inode);
535 return node ? inode : NULL;
539 * new_inode - obtain an inode
542 * Allocates a new inode for given superblock. The default gfp_mask
543 * for allocations related to inode->i_mapping is GFP_HIGHUSER_PAGECACHE.
544 * If HIGHMEM pages are unsuitable or it is known that pages allocated
545 * for the page cache are not reclaimable or migratable,
546 * mapping_set_gfp_mask() must be called with suitable flags on the
547 * newly created inode's mapping
550 struct inode *new_inode(struct super_block *sb)
553 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
554 * error if st_ino won't fit in target struct field. Use 32bit counter
555 * here to attempt to avoid that.
557 static unsigned int last_ino;
558 struct inode * inode;
560 spin_lock_prefetch(&inode_lock);
562 inode = alloc_inode(sb);
564 spin_lock(&inode_lock);
565 inodes_stat.nr_inodes++;
566 list_add(&inode->i_list, &inode_in_use);
567 list_add(&inode->i_sb_list, &sb->s_inodes);
568 inode->i_ino = ++last_ino;
570 spin_unlock(&inode_lock);
575 EXPORT_SYMBOL(new_inode);
577 void unlock_new_inode(struct inode *inode)
579 #ifdef CONFIG_DEBUG_LOCK_ALLOC
580 if (inode->i_mode & S_IFDIR) {
581 struct file_system_type *type = inode->i_sb->s_type;
584 * ensure nobody is actually holding i_mutex
586 mutex_destroy(&inode->i_mutex);
587 mutex_init(&inode->i_mutex);
588 lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key);
592 * This is special! We do not need the spinlock
593 * when clearing I_LOCK, because we're guaranteed
594 * that nobody else tries to do anything about the
595 * state of the inode when it is locked, as we
596 * just created it (so there can be no old holders
597 * that haven't tested I_LOCK).
599 inode->i_state &= ~(I_LOCK|I_NEW);
600 wake_up_inode(inode);
603 EXPORT_SYMBOL(unlock_new_inode);
606 * This is called without the inode lock held.. Be careful.
608 * We no longer cache the sb_flags in i_flags - see fs.h
609 * -- rmk@arm.uk.linux.org
611 static 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)
613 struct inode * inode;
615 inode = alloc_inode(sb);
619 spin_lock(&inode_lock);
620 /* We released the lock, so.. */
621 old = find_inode(sb, head, test, data);
623 if (set(inode, data))
626 inodes_stat.nr_inodes++;
627 list_add(&inode->i_list, &inode_in_use);
628 list_add(&inode->i_sb_list, &sb->s_inodes);
629 hlist_add_head(&inode->i_hash, head);
630 inode->i_state = I_LOCK|I_NEW;
631 spin_unlock(&inode_lock);
633 /* Return the locked inode with I_NEW set, the
634 * caller is responsible for filling in the contents
640 * Uhhuh, somebody else created the same inode under
641 * us. Use the old inode instead of the one we just
645 spin_unlock(&inode_lock);
646 destroy_inode(inode);
648 wait_on_inode(inode);
653 spin_unlock(&inode_lock);
654 destroy_inode(inode);
659 * get_new_inode_fast is the fast path version of get_new_inode, see the
660 * comment at iget_locked for details.
662 static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
664 struct inode * inode;
666 inode = alloc_inode(sb);
670 spin_lock(&inode_lock);
671 /* We released the lock, so.. */
672 old = find_inode_fast(sb, head, ino);
675 inodes_stat.nr_inodes++;
676 list_add(&inode->i_list, &inode_in_use);
677 list_add(&inode->i_sb_list, &sb->s_inodes);
678 hlist_add_head(&inode->i_hash, head);
679 inode->i_state = I_LOCK|I_NEW;
680 spin_unlock(&inode_lock);
682 /* Return the locked inode with I_NEW set, the
683 * caller is responsible for filling in the contents
689 * Uhhuh, somebody else created the same inode under
690 * us. Use the old inode instead of the one we just
694 spin_unlock(&inode_lock);
695 destroy_inode(inode);
697 wait_on_inode(inode);
702 static unsigned long hash(struct super_block *sb, unsigned long hashval)
706 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
708 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
709 return tmp & I_HASHMASK;
713 * iunique - get a unique inode number
715 * @max_reserved: highest reserved inode number
717 * Obtain an inode number that is unique on the system for a given
718 * superblock. This is used by file systems that have no natural
719 * permanent inode numbering system. An inode number is returned that
720 * is higher than the reserved limit but unique.
723 * With a large number of inodes live on the file system this function
724 * currently becomes quite slow.
726 ino_t iunique(struct super_block *sb, ino_t max_reserved)
729 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
730 * error if st_ino won't fit in target struct field. Use 32bit counter
731 * here to attempt to avoid that.
733 static unsigned int counter;
735 struct hlist_head *head;
738 spin_lock(&inode_lock);
740 if (counter <= max_reserved)
741 counter = max_reserved + 1;
743 head = inode_hashtable + hash(sb, res);
744 inode = find_inode_fast(sb, head, res);
745 } while (inode != NULL);
746 spin_unlock(&inode_lock);
750 EXPORT_SYMBOL(iunique);
752 struct inode *igrab(struct inode *inode)
754 spin_lock(&inode_lock);
755 if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
759 * Handle the case where s_op->clear_inode is not been
760 * called yet, and somebody is calling igrab
761 * while the inode is getting freed.
764 spin_unlock(&inode_lock);
768 EXPORT_SYMBOL(igrab);
771 * ifind - internal function, you want ilookup5() or iget5().
772 * @sb: super block of file system to search
773 * @head: the head of the list to search
774 * @test: callback used for comparisons between inodes
775 * @data: opaque data pointer to pass to @test
776 * @wait: if true wait for the inode to be unlocked, if false do not
778 * ifind() searches for the inode specified by @data in the inode
779 * cache. This is a generalized version of ifind_fast() for file systems where
780 * the inode number is not sufficient for unique identification of an inode.
782 * If the inode is in the cache, the inode is returned with an incremented
785 * Otherwise NULL is returned.
787 * Note, @test is called with the inode_lock held, so can't sleep.
789 static struct inode *ifind(struct super_block *sb,
790 struct hlist_head *head, int (*test)(struct inode *, void *),
791 void *data, const int wait)
795 spin_lock(&inode_lock);
796 inode = find_inode(sb, head, test, data);
799 spin_unlock(&inode_lock);
801 wait_on_inode(inode);
804 spin_unlock(&inode_lock);
809 * ifind_fast - internal function, you want ilookup() or iget().
810 * @sb: super block of file system to search
811 * @head: head of the list to search
812 * @ino: inode number to search for
814 * ifind_fast() searches for the inode @ino in the inode cache. This is for
815 * file systems where the inode number is sufficient for unique identification
818 * If the inode is in the cache, the inode is returned with an incremented
821 * Otherwise NULL is returned.
823 static struct inode *ifind_fast(struct super_block *sb,
824 struct hlist_head *head, unsigned long ino)
828 spin_lock(&inode_lock);
829 inode = find_inode_fast(sb, head, ino);
832 spin_unlock(&inode_lock);
833 wait_on_inode(inode);
836 spin_unlock(&inode_lock);
841 * ilookup5_nowait - search for an inode in the inode cache
842 * @sb: super block of file system to search
843 * @hashval: hash value (usually inode number) to search for
844 * @test: callback used for comparisons between inodes
845 * @data: opaque data pointer to pass to @test
847 * ilookup5() uses ifind() to search for the inode specified by @hashval and
848 * @data in the inode cache. This is a generalized version of ilookup() for
849 * file systems where the inode number is not sufficient for unique
850 * identification of an inode.
852 * If the inode is in the cache, the inode is returned with an incremented
853 * reference count. Note, the inode lock is not waited upon so you have to be
854 * very careful what you do with the returned inode. You probably should be
855 * using ilookup5() instead.
857 * Otherwise NULL is returned.
859 * Note, @test is called with the inode_lock held, so can't sleep.
861 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
862 int (*test)(struct inode *, void *), void *data)
864 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
866 return ifind(sb, head, test, data, 0);
869 EXPORT_SYMBOL(ilookup5_nowait);
872 * ilookup5 - search for an inode in the inode cache
873 * @sb: super block of file system to search
874 * @hashval: hash value (usually inode number) to search for
875 * @test: callback used for comparisons between inodes
876 * @data: opaque data pointer to pass to @test
878 * ilookup5() uses ifind() to search for the inode specified by @hashval and
879 * @data in the inode cache. This is a generalized version of ilookup() for
880 * file systems where the inode number is not sufficient for unique
881 * identification of an inode.
883 * If the inode is in the cache, the inode lock is waited upon and the inode is
884 * returned with an incremented reference count.
886 * Otherwise NULL is returned.
888 * Note, @test is called with the inode_lock held, so can't sleep.
890 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
891 int (*test)(struct inode *, void *), void *data)
893 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
895 return ifind(sb, head, test, data, 1);
898 EXPORT_SYMBOL(ilookup5);
901 * ilookup - search for an inode in the inode cache
902 * @sb: super block of file system to search
903 * @ino: inode number to search for
905 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
906 * This is for file systems where the inode number is sufficient for unique
907 * identification of an inode.
909 * If the inode is in the cache, the inode is returned with an incremented
912 * Otherwise NULL is returned.
914 struct inode *ilookup(struct super_block *sb, unsigned long ino)
916 struct hlist_head *head = inode_hashtable + hash(sb, ino);
918 return ifind_fast(sb, head, ino);
921 EXPORT_SYMBOL(ilookup);
924 * iget5_locked - obtain an inode from a mounted file system
925 * @sb: super block of file system
926 * @hashval: hash value (usually inode number) to get
927 * @test: callback used for comparisons between inodes
928 * @set: callback used to initialize a new struct inode
929 * @data: opaque data pointer to pass to @test and @set
931 * iget5_locked() uses ifind() to search for the inode specified by @hashval
932 * and @data in the inode cache and if present it is returned with an increased
933 * reference count. This is a generalized version of iget_locked() for file
934 * systems where the inode number is not sufficient for unique identification
937 * If the inode is not in cache, get_new_inode() is called to allocate a new
938 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
939 * file system gets to fill it in before unlocking it via unlock_new_inode().
941 * Note both @test and @set are called with the inode_lock held, so can't sleep.
943 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
944 int (*test)(struct inode *, void *),
945 int (*set)(struct inode *, void *), void *data)
947 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
950 inode = ifind(sb, head, test, data, 1);
954 * get_new_inode() will do the right thing, re-trying the search
955 * in case it had to block at any point.
957 return get_new_inode(sb, head, test, set, data);
960 EXPORT_SYMBOL(iget5_locked);
963 * iget_locked - obtain an inode from a mounted file system
964 * @sb: super block of file system
965 * @ino: inode number to get
967 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
968 * the inode cache and if present it is returned with an increased reference
969 * count. This is for file systems where the inode number is sufficient for
970 * unique identification of an inode.
972 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
973 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
974 * The file system gets to fill it in before unlocking it via
975 * unlock_new_inode().
977 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
979 struct hlist_head *head = inode_hashtable + hash(sb, ino);
982 inode = ifind_fast(sb, head, ino);
986 * get_new_inode_fast() will do the right thing, re-trying the search
987 * in case it had to block at any point.
989 return get_new_inode_fast(sb, head, ino);
992 EXPORT_SYMBOL(iget_locked);
995 * __insert_inode_hash - hash an inode
996 * @inode: unhashed inode
997 * @hashval: unsigned long value used to locate this object in the
1000 * Add an inode to the inode hash for this superblock.
1002 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
1004 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
1005 spin_lock(&inode_lock);
1006 hlist_add_head(&inode->i_hash, head);
1007 spin_unlock(&inode_lock);
1010 EXPORT_SYMBOL(__insert_inode_hash);
1013 * remove_inode_hash - remove an inode from the hash
1014 * @inode: inode to unhash
1016 * Remove an inode from the superblock.
1018 void remove_inode_hash(struct inode *inode)
1020 spin_lock(&inode_lock);
1021 hlist_del_init(&inode->i_hash);
1022 spin_unlock(&inode_lock);
1025 EXPORT_SYMBOL(remove_inode_hash);
1028 * Tell the filesystem that this inode is no longer of any interest and should
1029 * be completely destroyed.
1031 * We leave the inode in the inode hash table until *after* the filesystem's
1032 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1033 * instigate) will always find up-to-date information either in the hash or on
1036 * I_FREEING is set so that no-one will take a new reference to the inode while
1037 * it is being deleted.
1039 void generic_delete_inode(struct inode *inode)
1041 const struct super_operations *op = inode->i_sb->s_op;
1043 list_del_init(&inode->i_list);
1044 list_del_init(&inode->i_sb_list);
1045 inode->i_state |= I_FREEING;
1046 inodes_stat.nr_inodes--;
1047 spin_unlock(&inode_lock);
1049 security_inode_delete(inode);
1051 if (op->delete_inode) {
1052 void (*delete)(struct inode *) = op->delete_inode;
1053 if (!is_bad_inode(inode))
1055 /* Filesystems implementing their own
1056 * s_op->delete_inode are required to call
1057 * truncate_inode_pages and clear_inode()
1061 truncate_inode_pages(&inode->i_data, 0);
1064 spin_lock(&inode_lock);
1065 hlist_del_init(&inode->i_hash);
1066 spin_unlock(&inode_lock);
1067 wake_up_inode(inode);
1068 BUG_ON(inode->i_state != I_CLEAR);
1069 destroy_inode(inode);
1072 EXPORT_SYMBOL(generic_delete_inode);
1074 static void generic_forget_inode(struct inode *inode)
1076 struct super_block *sb = inode->i_sb;
1078 if (!hlist_unhashed(&inode->i_hash)) {
1079 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
1080 list_move(&inode->i_list, &inode_unused);
1081 inodes_stat.nr_unused++;
1082 if (sb->s_flags & MS_ACTIVE) {
1083 spin_unlock(&inode_lock);
1086 inode->i_state |= I_WILL_FREE;
1087 spin_unlock(&inode_lock);
1088 write_inode_now(inode, 1);
1089 spin_lock(&inode_lock);
1090 inode->i_state &= ~I_WILL_FREE;
1091 inodes_stat.nr_unused--;
1092 hlist_del_init(&inode->i_hash);
1094 list_del_init(&inode->i_list);
1095 list_del_init(&inode->i_sb_list);
1096 inode->i_state |= I_FREEING;
1097 inodes_stat.nr_inodes--;
1098 spin_unlock(&inode_lock);
1099 if (inode->i_data.nrpages)
1100 truncate_inode_pages(&inode->i_data, 0);
1102 wake_up_inode(inode);
1103 destroy_inode(inode);
1107 * Normal UNIX filesystem behaviour: delete the
1108 * inode when the usage count drops to zero, and
1111 void generic_drop_inode(struct inode *inode)
1113 if (!inode->i_nlink)
1114 generic_delete_inode(inode);
1116 generic_forget_inode(inode);
1119 EXPORT_SYMBOL_GPL(generic_drop_inode);
1122 * Called when we're dropping the last reference
1125 * Call the FS "drop()" function, defaulting to
1126 * the legacy UNIX filesystem behaviour..
1128 * NOTE! NOTE! NOTE! We're called with the inode lock
1129 * held, and the drop function is supposed to release
1132 static inline void iput_final(struct inode *inode)
1134 const struct super_operations *op = inode->i_sb->s_op;
1135 void (*drop)(struct inode *) = generic_drop_inode;
1137 if (op && op->drop_inode)
1138 drop = op->drop_inode;
1143 * iput - put an inode
1144 * @inode: inode to put
1146 * Puts an inode, dropping its usage count. If the inode use count hits
1147 * zero, the inode is then freed and may also be destroyed.
1149 * Consequently, iput() can sleep.
1151 void iput(struct inode *inode)
1154 const struct super_operations *op = inode->i_sb->s_op;
1156 BUG_ON(inode->i_state == I_CLEAR);
1158 if (op && op->put_inode)
1159 op->put_inode(inode);
1161 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1166 EXPORT_SYMBOL(iput);
1169 * bmap - find a block number in a file
1170 * @inode: inode of file
1171 * @block: block to find
1173 * Returns the block number on the device holding the inode that
1174 * is the disk block number for the block of the file requested.
1175 * That is, asked for block 4 of inode 1 the function will return the
1176 * disk block relative to the disk start that holds that block of the
1179 sector_t bmap(struct inode * inode, sector_t block)
1182 if (inode->i_mapping->a_ops->bmap)
1183 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1186 EXPORT_SYMBOL(bmap);
1189 * touch_atime - update the access time
1190 * @mnt: mount the inode is accessed on
1191 * @dentry: dentry accessed
1193 * Update the accessed time on an inode and mark it for writeback.
1194 * This function automatically handles read only file systems and media,
1195 * as well as the "noatime" flag and inode specific "noatime" markers.
1197 void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1199 struct inode *inode = dentry->d_inode;
1200 struct timespec now;
1202 if (inode->i_flags & S_NOATIME)
1204 if (IS_NOATIME(inode))
1206 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1210 * We may have a NULL vfsmount when coming from NFSD
1213 if (mnt->mnt_flags & MNT_NOATIME)
1215 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1218 if (mnt->mnt_flags & MNT_RELATIME) {
1220 * With relative atime, only update atime if the
1221 * previous atime is earlier than either the ctime or
1224 if (timespec_compare(&inode->i_mtime,
1225 &inode->i_atime) < 0 &&
1226 timespec_compare(&inode->i_ctime,
1227 &inode->i_atime) < 0)
1232 now = current_fs_time(inode->i_sb);
1233 if (timespec_equal(&inode->i_atime, &now))
1236 inode->i_atime = now;
1237 mark_inode_dirty_sync(inode);
1239 EXPORT_SYMBOL(touch_atime);
1242 * file_update_time - update mtime and ctime time
1243 * @file: file accessed
1245 * Update the mtime and ctime members of an inode and mark the inode
1246 * for writeback. Note that this function is meant exclusively for
1247 * usage in the file write path of filesystems, and filesystems may
1248 * choose to explicitly ignore update via this function with the
1249 * S_NOCTIME inode flag, e.g. for network filesystem where these
1250 * timestamps are handled by the server.
1253 void file_update_time(struct file *file)
1255 struct inode *inode = file->f_path.dentry->d_inode;
1256 struct timespec now;
1259 if (IS_NOCMTIME(inode))
1261 if (IS_RDONLY(inode))
1264 now = current_fs_time(inode->i_sb);
1265 if (!timespec_equal(&inode->i_mtime, &now)) {
1266 inode->i_mtime = now;
1270 if (!timespec_equal(&inode->i_ctime, &now)) {
1271 inode->i_ctime = now;
1275 if (IS_I_VERSION(inode)) {
1276 inode_inc_iversion(inode);
1281 mark_inode_dirty_sync(inode);
1284 EXPORT_SYMBOL(file_update_time);
1286 int inode_needs_sync(struct inode *inode)
1290 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1295 EXPORT_SYMBOL(inode_needs_sync);
1297 int inode_wait(void *word)
1304 * If we try to find an inode in the inode hash while it is being
1305 * deleted, we have to wait until the filesystem completes its
1306 * deletion before reporting that it isn't found. This function waits
1307 * until the deletion _might_ have completed. Callers are responsible
1308 * to recheck inode state.
1310 * It doesn't matter if I_LOCK is not set initially, a call to
1311 * wake_up_inode() after removing from the hash list will DTRT.
1313 * This is called with inode_lock held.
1315 static void __wait_on_freeing_inode(struct inode *inode)
1317 wait_queue_head_t *wq;
1318 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
1319 wq = bit_waitqueue(&inode->i_state, __I_LOCK);
1320 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1321 spin_unlock(&inode_lock);
1323 finish_wait(wq, &wait.wait);
1324 spin_lock(&inode_lock);
1328 * We rarely want to lock two inodes that do not have a parent/child
1329 * relationship (such as directory, child inode) simultaneously. The
1330 * vast majority of file systems should be able to get along fine
1331 * without this. Do not use these functions except as a last resort.
1333 void inode_double_lock(struct inode *inode1, struct inode *inode2)
1335 if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
1337 mutex_lock(&inode1->i_mutex);
1339 mutex_lock(&inode2->i_mutex);
1343 if (inode1 < inode2) {
1344 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1345 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1347 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1348 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1351 EXPORT_SYMBOL(inode_double_lock);
1353 void inode_double_unlock(struct inode *inode1, struct inode *inode2)
1356 mutex_unlock(&inode1->i_mutex);
1358 if (inode2 && inode2 != inode1)
1359 mutex_unlock(&inode2->i_mutex);
1361 EXPORT_SYMBOL(inode_double_unlock);
1363 static __initdata unsigned long ihash_entries;
1364 static int __init set_ihash_entries(char *str)
1368 ihash_entries = simple_strtoul(str, &str, 0);
1371 __setup("ihash_entries=", set_ihash_entries);
1374 * Initialize the waitqueues and inode hash table.
1376 void __init inode_init_early(void)
1380 /* If hashes are distributed across NUMA nodes, defer
1381 * hash allocation until vmalloc space is available.
1387 alloc_large_system_hash("Inode-cache",
1388 sizeof(struct hlist_head),
1396 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1397 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1400 void __init inode_init(void)
1404 /* inode slab cache */
1405 inode_cachep = kmem_cache_create("inode_cache",
1406 sizeof(struct inode),
1408 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1411 register_shrinker(&icache_shrinker);
1413 /* Hash may have been set up in inode_init_early */
1418 alloc_large_system_hash("Inode-cache",
1419 sizeof(struct hlist_head),
1427 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1428 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1431 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1433 inode->i_mode = mode;
1434 if (S_ISCHR(mode)) {
1435 inode->i_fop = &def_chr_fops;
1436 inode->i_rdev = rdev;
1437 } else if (S_ISBLK(mode)) {
1438 inode->i_fop = &def_blk_fops;
1439 inode->i_rdev = rdev;
1440 } else if (S_ISFIFO(mode))
1441 inode->i_fop = &def_fifo_fops;
1442 else if (S_ISSOCK(mode))
1443 inode->i_fop = &bad_sock_fops;
1445 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
1448 EXPORT_SYMBOL(init_special_inode);