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/ima.h>
21 #include <linux/pagemap.h>
22 #include <linux/cdev.h>
23 #include <linux/bootmem.h>
24 #include <linux/inotify.h>
25 #include <linux/fsnotify.h>
26 #include <linux/mount.h>
27 #include <linux/async.h>
30 * This is needed for the following functions:
32 * - invalidate_inode_buffers
35 * FIXME: remove all knowledge of the buffer layer from this file
37 #include <linux/buffer_head.h>
40 * New inode.c implementation.
42 * This implementation has the basic premise of trying
43 * to be extremely low-overhead and SMP-safe, yet be
44 * simple enough to be "obviously correct".
49 /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
51 /* #define INODE_PARANOIA 1 */
52 /* #define INODE_DEBUG 1 */
55 * Inode lookup is no longer as critical as it used to be:
56 * most of the lookups are going to be through the dcache.
58 #define I_HASHBITS i_hash_shift
59 #define I_HASHMASK i_hash_mask
61 static unsigned int i_hash_mask __read_mostly;
62 static unsigned int i_hash_shift __read_mostly;
65 * Each inode can be on two separate lists. One is
66 * the hash list of the inode, used for lookups. The
67 * other linked list is the "type" list:
68 * "in_use" - valid inode, i_count > 0, i_nlink > 0
69 * "dirty" - as "in_use" but also dirty
70 * "unused" - valid inode, i_count = 0
72 * A "dirty" list is maintained for each super block,
73 * allowing for low-overhead inode sync() operations.
76 LIST_HEAD(inode_in_use);
77 LIST_HEAD(inode_unused);
78 static struct hlist_head *inode_hashtable __read_mostly;
81 * A simple spinlock to protect the list manipulations.
83 * NOTE! You also have to own the lock if you change
84 * the i_state of an inode while it is in use..
86 DEFINE_SPINLOCK(inode_lock);
89 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
90 * icache shrinking path, and the umount path. Without this exclusion,
91 * by the time prune_icache calls iput for the inode whose pages it has
92 * been invalidating, or by the time it calls clear_inode & destroy_inode
93 * from its final dispose_list, the struct super_block they refer to
94 * (for inode->i_sb->s_op) may already have been freed and reused.
96 static DEFINE_MUTEX(iprune_mutex);
99 * Statistics gathering..
101 struct inodes_stat_t inodes_stat;
103 static struct kmem_cache *inode_cachep __read_mostly;
105 static void wake_up_inode(struct inode *inode)
108 * Prevent speculative execution through spin_unlock(&inode_lock);
111 wake_up_bit(&inode->i_state, __I_LOCK);
115 * inode_init_always - perform inode structure intialisation
116 * @sb: superblock inode belongs to
117 * @inode: inode to initialise
119 * These are initializations that need to be done on every inode
120 * allocation as the fields are not initialised by slab allocation.
122 struct inode *inode_init_always(struct super_block *sb, struct inode *inode)
124 static const struct address_space_operations empty_aops;
125 static struct inode_operations empty_iops;
126 static const struct file_operations empty_fops;
128 struct address_space *const mapping = &inode->i_data;
131 inode->i_blkbits = sb->s_blocksize_bits;
133 atomic_set(&inode->i_count, 1);
134 inode->i_op = &empty_iops;
135 inode->i_fop = &empty_fops;
139 atomic_set(&inode->i_writecount, 0);
143 inode->i_generation = 0;
145 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
147 inode->i_pipe = NULL;
148 inode->i_bdev = NULL;
149 inode->i_cdev = NULL;
151 inode->dirtied_when = 0;
153 if (security_inode_alloc(inode))
156 /* allocate and initialize an i_integrity */
157 if (ima_inode_alloc(inode))
158 goto out_free_security;
160 spin_lock_init(&inode->i_lock);
161 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
163 mutex_init(&inode->i_mutex);
164 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
166 init_rwsem(&inode->i_alloc_sem);
167 lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
169 mapping->a_ops = &empty_aops;
170 mapping->host = inode;
172 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
173 mapping->assoc_mapping = NULL;
174 mapping->backing_dev_info = &default_backing_dev_info;
175 mapping->writeback_index = 0;
178 * If the block_device provides a backing_dev_info for client
179 * inodes then use that. Otherwise the inode share the bdev's
183 struct backing_dev_info *bdi;
185 bdi = sb->s_bdev->bd_inode_backing_dev_info;
187 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
188 mapping->backing_dev_info = bdi;
190 inode->i_private = NULL;
191 inode->i_mapping = mapping;
193 #ifdef CONFIG_FSNOTIFY
194 inode->i_fsnotify_mask = 0;
200 security_inode_free(inode);
202 if (inode->i_sb->s_op->destroy_inode)
203 inode->i_sb->s_op->destroy_inode(inode);
205 kmem_cache_free(inode_cachep, (inode));
208 EXPORT_SYMBOL(inode_init_always);
210 static struct inode *alloc_inode(struct super_block *sb)
214 if (sb->s_op->alloc_inode)
215 inode = sb->s_op->alloc_inode(sb);
217 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
220 return inode_init_always(sb, inode);
224 void destroy_inode(struct inode *inode)
226 BUG_ON(inode_has_buffers(inode));
227 ima_inode_free(inode);
228 security_inode_free(inode);
229 fsnotify_inode_delete(inode);
230 if (inode->i_sb->s_op->destroy_inode)
231 inode->i_sb->s_op->destroy_inode(inode);
233 kmem_cache_free(inode_cachep, (inode));
235 EXPORT_SYMBOL(destroy_inode);
239 * These are initializations that only need to be done
240 * once, because the fields are idempotent across use
241 * of the inode, so let the slab aware of that.
243 void inode_init_once(struct inode *inode)
245 memset(inode, 0, sizeof(*inode));
246 INIT_HLIST_NODE(&inode->i_hash);
247 INIT_LIST_HEAD(&inode->i_dentry);
248 INIT_LIST_HEAD(&inode->i_devices);
249 INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
250 spin_lock_init(&inode->i_data.tree_lock);
251 spin_lock_init(&inode->i_data.i_mmap_lock);
252 INIT_LIST_HEAD(&inode->i_data.private_list);
253 spin_lock_init(&inode->i_data.private_lock);
254 INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
255 INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
256 i_size_ordered_init(inode);
257 #ifdef CONFIG_INOTIFY
258 INIT_LIST_HEAD(&inode->inotify_watches);
259 mutex_init(&inode->inotify_mutex);
261 #ifdef CONFIG_FSNOTIFY
262 INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries);
265 EXPORT_SYMBOL(inode_init_once);
267 static void init_once(void *foo)
269 struct inode *inode = (struct inode *) foo;
271 inode_init_once(inode);
275 * inode_lock must be held
277 void __iget(struct inode *inode)
279 if (atomic_read(&inode->i_count)) {
280 atomic_inc(&inode->i_count);
283 atomic_inc(&inode->i_count);
284 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
285 list_move(&inode->i_list, &inode_in_use);
286 inodes_stat.nr_unused--;
290 * clear_inode - clear an inode
291 * @inode: inode to clear
293 * This is called by the filesystem to tell us
294 * that the inode is no longer useful. We just
295 * terminate it with extreme prejudice.
297 void clear_inode(struct inode *inode)
300 invalidate_inode_buffers(inode);
302 BUG_ON(inode->i_data.nrpages);
303 BUG_ON(!(inode->i_state & I_FREEING));
304 BUG_ON(inode->i_state & I_CLEAR);
305 inode_sync_wait(inode);
307 if (inode->i_sb->s_op->clear_inode)
308 inode->i_sb->s_op->clear_inode(inode);
309 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
311 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
313 inode->i_state = I_CLEAR;
315 EXPORT_SYMBOL(clear_inode);
318 * dispose_list - dispose of the contents of a local list
319 * @head: the head of the list to free
321 * Dispose-list gets a local list with local inodes in it, so it doesn't
322 * need to worry about list corruption and SMP locks.
324 static void dispose_list(struct list_head *head)
328 while (!list_empty(head)) {
331 inode = list_first_entry(head, struct inode, i_list);
332 list_del(&inode->i_list);
334 if (inode->i_data.nrpages)
335 truncate_inode_pages(&inode->i_data, 0);
338 spin_lock(&inode_lock);
339 hlist_del_init(&inode->i_hash);
340 list_del_init(&inode->i_sb_list);
341 spin_unlock(&inode_lock);
343 wake_up_inode(inode);
344 destroy_inode(inode);
347 spin_lock(&inode_lock);
348 inodes_stat.nr_inodes -= nr_disposed;
349 spin_unlock(&inode_lock);
353 * Invalidate all inodes for a device.
355 static int invalidate_list(struct list_head *head, struct list_head *dispose)
357 struct list_head *next;
358 int busy = 0, count = 0;
362 struct list_head *tmp = next;
366 * We can reschedule here without worrying about the list's
367 * consistency because the per-sb list of inodes must not
368 * change during umount anymore, and because iprune_mutex keeps
369 * shrink_icache_memory() away.
371 cond_resched_lock(&inode_lock);
376 inode = list_entry(tmp, struct inode, i_sb_list);
377 if (inode->i_state & I_NEW)
379 invalidate_inode_buffers(inode);
380 if (!atomic_read(&inode->i_count)) {
381 list_move(&inode->i_list, dispose);
382 WARN_ON(inode->i_state & I_NEW);
383 inode->i_state |= I_FREEING;
389 /* only unused inodes may be cached with i_count zero */
390 inodes_stat.nr_unused -= count;
395 * invalidate_inodes - discard the inodes on a device
398 * Discard all of the inodes for a given superblock. If the discard
399 * fails because there are busy inodes then a non zero value is returned.
400 * If the discard is successful all the inodes have been discarded.
402 int invalidate_inodes(struct super_block *sb)
405 LIST_HEAD(throw_away);
407 mutex_lock(&iprune_mutex);
408 spin_lock(&inode_lock);
409 inotify_unmount_inodes(&sb->s_inodes);
410 fsnotify_unmount_inodes(&sb->s_inodes);
411 busy = invalidate_list(&sb->s_inodes, &throw_away);
412 spin_unlock(&inode_lock);
414 dispose_list(&throw_away);
415 mutex_unlock(&iprune_mutex);
419 EXPORT_SYMBOL(invalidate_inodes);
421 static int can_unuse(struct inode *inode)
425 if (inode_has_buffers(inode))
427 if (atomic_read(&inode->i_count))
429 if (inode->i_data.nrpages)
435 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
436 * a temporary list and then are freed outside inode_lock by dispose_list().
438 * Any inodes which are pinned purely because of attached pagecache have their
439 * pagecache removed. We expect the final iput() on that inode to add it to
440 * the front of the inode_unused list. So look for it there and if the
441 * inode is still freeable, proceed. The right inode is found 99.9% of the
442 * time in testing on a 4-way.
444 * If the inode has metadata buffers attached to mapping->private_list then
445 * try to remove them.
447 static void prune_icache(int nr_to_scan)
452 unsigned long reap = 0;
454 mutex_lock(&iprune_mutex);
455 spin_lock(&inode_lock);
456 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
459 if (list_empty(&inode_unused))
462 inode = list_entry(inode_unused.prev, struct inode, i_list);
464 if (inode->i_state || atomic_read(&inode->i_count)) {
465 list_move(&inode->i_list, &inode_unused);
468 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
470 spin_unlock(&inode_lock);
471 if (remove_inode_buffers(inode))
472 reap += invalidate_mapping_pages(&inode->i_data,
475 spin_lock(&inode_lock);
477 if (inode != list_entry(inode_unused.next,
478 struct inode, i_list))
479 continue; /* wrong inode or list_empty */
480 if (!can_unuse(inode))
483 list_move(&inode->i_list, &freeable);
484 WARN_ON(inode->i_state & I_NEW);
485 inode->i_state |= I_FREEING;
488 inodes_stat.nr_unused -= nr_pruned;
489 if (current_is_kswapd())
490 __count_vm_events(KSWAPD_INODESTEAL, reap);
492 __count_vm_events(PGINODESTEAL, reap);
493 spin_unlock(&inode_lock);
495 dispose_list(&freeable);
496 mutex_unlock(&iprune_mutex);
500 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
501 * "unused" means that no dentries are referring to the inodes: the files are
502 * not open and the dcache references to those inodes have already been
505 * This function is passed the number of inodes to scan, and it returns the
506 * total number of remaining possibly-reclaimable inodes.
508 static int shrink_icache_memory(int nr, gfp_t gfp_mask)
512 * Nasty deadlock avoidance. We may hold various FS locks,
513 * and we don't want to recurse into the FS that called us
514 * in clear_inode() and friends..
516 if (!(gfp_mask & __GFP_FS))
520 return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
523 static struct shrinker icache_shrinker = {
524 .shrink = shrink_icache_memory,
525 .seeks = DEFAULT_SEEKS,
528 static void __wait_on_freeing_inode(struct inode *inode);
530 * Called with the inode lock held.
531 * NOTE: we are not increasing the inode-refcount, you must call __iget()
532 * by hand after calling find_inode now! This simplifies iunique and won't
533 * add any additional branch in the common code.
535 static struct inode *find_inode(struct super_block *sb,
536 struct hlist_head *head,
537 int (*test)(struct inode *, void *),
540 struct hlist_node *node;
541 struct inode *inode = NULL;
544 hlist_for_each_entry(inode, node, head, i_hash) {
545 if (inode->i_sb != sb)
547 if (!test(inode, data))
549 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
550 __wait_on_freeing_inode(inode);
555 return node ? inode : NULL;
559 * find_inode_fast is the fast path version of find_inode, see the comment at
560 * iget_locked for details.
562 static struct inode *find_inode_fast(struct super_block *sb,
563 struct hlist_head *head, unsigned long ino)
565 struct hlist_node *node;
566 struct inode *inode = NULL;
569 hlist_for_each_entry(inode, node, head, i_hash) {
570 if (inode->i_ino != ino)
572 if (inode->i_sb != sb)
574 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
575 __wait_on_freeing_inode(inode);
580 return node ? inode : NULL;
583 static unsigned long hash(struct super_block *sb, unsigned long hashval)
587 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
589 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
590 return tmp & I_HASHMASK;
594 __inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
597 inodes_stat.nr_inodes++;
598 list_add(&inode->i_list, &inode_in_use);
599 list_add(&inode->i_sb_list, &sb->s_inodes);
601 hlist_add_head(&inode->i_hash, head);
605 * inode_add_to_lists - add a new inode to relevant lists
606 * @sb: superblock inode belongs to
607 * @inode: inode to mark in use
609 * When an inode is allocated it needs to be accounted for, added to the in use
610 * list, the owning superblock and the inode hash. This needs to be done under
611 * the inode_lock, so export a function to do this rather than the inode lock
612 * itself. We calculate the hash list to add to here so it is all internal
613 * which requires the caller to have already set up the inode number in the
616 void inode_add_to_lists(struct super_block *sb, struct inode *inode)
618 struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
620 spin_lock(&inode_lock);
621 __inode_add_to_lists(sb, head, inode);
622 spin_unlock(&inode_lock);
624 EXPORT_SYMBOL_GPL(inode_add_to_lists);
627 * new_inode - obtain an inode
630 * Allocates a new inode for given superblock. The default gfp_mask
631 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
632 * If HIGHMEM pages are unsuitable or it is known that pages allocated
633 * for the page cache are not reclaimable or migratable,
634 * mapping_set_gfp_mask() must be called with suitable flags on the
635 * newly created inode's mapping
638 struct inode *new_inode(struct super_block *sb)
641 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
642 * error if st_ino won't fit in target struct field. Use 32bit counter
643 * here to attempt to avoid that.
645 static unsigned int last_ino;
648 spin_lock_prefetch(&inode_lock);
650 inode = alloc_inode(sb);
652 spin_lock(&inode_lock);
653 __inode_add_to_lists(sb, NULL, inode);
654 inode->i_ino = ++last_ino;
656 spin_unlock(&inode_lock);
660 EXPORT_SYMBOL(new_inode);
662 void unlock_new_inode(struct inode *inode)
664 #ifdef CONFIG_DEBUG_LOCK_ALLOC
665 if (inode->i_mode & S_IFDIR) {
666 struct file_system_type *type = inode->i_sb->s_type;
668 /* Set new key only if filesystem hasn't already changed it */
669 if (!lockdep_match_class(&inode->i_mutex,
670 &type->i_mutex_key)) {
672 * ensure nobody is actually holding i_mutex
674 mutex_destroy(&inode->i_mutex);
675 mutex_init(&inode->i_mutex);
676 lockdep_set_class(&inode->i_mutex,
677 &type->i_mutex_dir_key);
682 * This is special! We do not need the spinlock
683 * when clearing I_LOCK, because we're guaranteed
684 * that nobody else tries to do anything about the
685 * state of the inode when it is locked, as we
686 * just created it (so there can be no old holders
687 * that haven't tested I_LOCK).
689 WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW));
690 inode->i_state &= ~(I_LOCK|I_NEW);
691 wake_up_inode(inode);
693 EXPORT_SYMBOL(unlock_new_inode);
696 * This is called without the inode lock held.. Be careful.
698 * We no longer cache the sb_flags in i_flags - see fs.h
699 * -- rmk@arm.uk.linux.org
701 static struct inode *get_new_inode(struct super_block *sb,
702 struct hlist_head *head,
703 int (*test)(struct inode *, void *),
704 int (*set)(struct inode *, void *),
709 inode = alloc_inode(sb);
713 spin_lock(&inode_lock);
714 /* We released the lock, so.. */
715 old = find_inode(sb, head, test, data);
717 if (set(inode, data))
720 __inode_add_to_lists(sb, head, inode);
721 inode->i_state = I_LOCK|I_NEW;
722 spin_unlock(&inode_lock);
724 /* Return the locked inode with I_NEW set, the
725 * caller is responsible for filling in the contents
731 * Uhhuh, somebody else created the same inode under
732 * us. Use the old inode instead of the one we just
736 spin_unlock(&inode_lock);
737 destroy_inode(inode);
739 wait_on_inode(inode);
744 spin_unlock(&inode_lock);
745 destroy_inode(inode);
750 * get_new_inode_fast is the fast path version of get_new_inode, see the
751 * comment at iget_locked for details.
753 static struct inode *get_new_inode_fast(struct super_block *sb,
754 struct hlist_head *head, unsigned long ino)
758 inode = alloc_inode(sb);
762 spin_lock(&inode_lock);
763 /* We released the lock, so.. */
764 old = find_inode_fast(sb, head, ino);
767 __inode_add_to_lists(sb, head, inode);
768 inode->i_state = I_LOCK|I_NEW;
769 spin_unlock(&inode_lock);
771 /* Return the locked inode with I_NEW set, the
772 * caller is responsible for filling in the contents
778 * Uhhuh, somebody else created the same inode under
779 * us. Use the old inode instead of the one we just
783 spin_unlock(&inode_lock);
784 destroy_inode(inode);
786 wait_on_inode(inode);
792 * iunique - get a unique inode number
794 * @max_reserved: highest reserved inode number
796 * Obtain an inode number that is unique on the system for a given
797 * superblock. This is used by file systems that have no natural
798 * permanent inode numbering system. An inode number is returned that
799 * is higher than the reserved limit but unique.
802 * With a large number of inodes live on the file system this function
803 * currently becomes quite slow.
805 ino_t iunique(struct super_block *sb, ino_t max_reserved)
808 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
809 * error if st_ino won't fit in target struct field. Use 32bit counter
810 * here to attempt to avoid that.
812 static unsigned int counter;
814 struct hlist_head *head;
817 spin_lock(&inode_lock);
819 if (counter <= max_reserved)
820 counter = max_reserved + 1;
822 head = inode_hashtable + hash(sb, res);
823 inode = find_inode_fast(sb, head, res);
824 } while (inode != NULL);
825 spin_unlock(&inode_lock);
829 EXPORT_SYMBOL(iunique);
831 struct inode *igrab(struct inode *inode)
833 spin_lock(&inode_lock);
834 if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
838 * Handle the case where s_op->clear_inode is not been
839 * called yet, and somebody is calling igrab
840 * while the inode is getting freed.
843 spin_unlock(&inode_lock);
846 EXPORT_SYMBOL(igrab);
849 * ifind - internal function, you want ilookup5() or iget5().
850 * @sb: super block of file system to search
851 * @head: the head of the list to search
852 * @test: callback used for comparisons between inodes
853 * @data: opaque data pointer to pass to @test
854 * @wait: if true wait for the inode to be unlocked, if false do not
856 * ifind() searches for the inode specified by @data in the inode
857 * cache. This is a generalized version of ifind_fast() for file systems where
858 * the inode number is not sufficient for unique identification of an inode.
860 * If the inode is in the cache, the inode is returned with an incremented
863 * Otherwise NULL is returned.
865 * Note, @test is called with the inode_lock held, so can't sleep.
867 static struct inode *ifind(struct super_block *sb,
868 struct hlist_head *head, int (*test)(struct inode *, void *),
869 void *data, const int wait)
873 spin_lock(&inode_lock);
874 inode = find_inode(sb, head, test, data);
877 spin_unlock(&inode_lock);
879 wait_on_inode(inode);
882 spin_unlock(&inode_lock);
887 * ifind_fast - internal function, you want ilookup() or iget().
888 * @sb: super block of file system to search
889 * @head: head of the list to search
890 * @ino: inode number to search for
892 * ifind_fast() searches for the inode @ino in the inode cache. This is for
893 * file systems where the inode number is sufficient for unique identification
896 * If the inode is in the cache, the inode is returned with an incremented
899 * Otherwise NULL is returned.
901 static struct inode *ifind_fast(struct super_block *sb,
902 struct hlist_head *head, unsigned long ino)
906 spin_lock(&inode_lock);
907 inode = find_inode_fast(sb, head, ino);
910 spin_unlock(&inode_lock);
911 wait_on_inode(inode);
914 spin_unlock(&inode_lock);
919 * ilookup5_nowait - search for an inode in the inode cache
920 * @sb: super block of file system to search
921 * @hashval: hash value (usually inode number) to search for
922 * @test: callback used for comparisons between inodes
923 * @data: opaque data pointer to pass to @test
925 * ilookup5() uses ifind() to search for the inode specified by @hashval and
926 * @data in the inode cache. This is a generalized version of ilookup() for
927 * file systems where the inode number is not sufficient for unique
928 * identification of an inode.
930 * If the inode is in the cache, the inode is returned with an incremented
931 * reference count. Note, the inode lock is not waited upon so you have to be
932 * very careful what you do with the returned inode. You probably should be
933 * using ilookup5() instead.
935 * Otherwise NULL is returned.
937 * Note, @test is called with the inode_lock held, so can't sleep.
939 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
940 int (*test)(struct inode *, void *), void *data)
942 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
944 return ifind(sb, head, test, data, 0);
946 EXPORT_SYMBOL(ilookup5_nowait);
949 * ilookup5 - search for an inode in the inode cache
950 * @sb: super block of file system to search
951 * @hashval: hash value (usually inode number) to search for
952 * @test: callback used for comparisons between inodes
953 * @data: opaque data pointer to pass to @test
955 * ilookup5() uses ifind() to search for the inode specified by @hashval and
956 * @data in the inode cache. This is a generalized version of ilookup() for
957 * file systems where the inode number is not sufficient for unique
958 * identification of an inode.
960 * If the inode is in the cache, the inode lock is waited upon and the inode is
961 * returned with an incremented reference count.
963 * Otherwise NULL is returned.
965 * Note, @test is called with the inode_lock held, so can't sleep.
967 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
968 int (*test)(struct inode *, void *), void *data)
970 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
972 return ifind(sb, head, test, data, 1);
974 EXPORT_SYMBOL(ilookup5);
977 * ilookup - search for an inode in the inode cache
978 * @sb: super block of file system to search
979 * @ino: inode number to search for
981 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
982 * This is for file systems where the inode number is sufficient for unique
983 * identification of an inode.
985 * If the inode is in the cache, the inode is returned with an incremented
988 * Otherwise NULL is returned.
990 struct inode *ilookup(struct super_block *sb, unsigned long ino)
992 struct hlist_head *head = inode_hashtable + hash(sb, ino);
994 return ifind_fast(sb, head, ino);
996 EXPORT_SYMBOL(ilookup);
999 * iget5_locked - obtain an inode from a mounted file system
1000 * @sb: super block of file system
1001 * @hashval: hash value (usually inode number) to get
1002 * @test: callback used for comparisons between inodes
1003 * @set: callback used to initialize a new struct inode
1004 * @data: opaque data pointer to pass to @test and @set
1006 * iget5_locked() uses ifind() to search for the inode specified by @hashval
1007 * and @data in the inode cache and if present it is returned with an increased
1008 * reference count. This is a generalized version of iget_locked() for file
1009 * systems where the inode number is not sufficient for unique identification
1012 * If the inode is not in cache, get_new_inode() is called to allocate a new
1013 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
1014 * file system gets to fill it in before unlocking it via unlock_new_inode().
1016 * Note both @test and @set are called with the inode_lock held, so can't sleep.
1018 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1019 int (*test)(struct inode *, void *),
1020 int (*set)(struct inode *, void *), void *data)
1022 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1023 struct inode *inode;
1025 inode = ifind(sb, head, test, data, 1);
1029 * get_new_inode() will do the right thing, re-trying the search
1030 * in case it had to block at any point.
1032 return get_new_inode(sb, head, test, set, data);
1034 EXPORT_SYMBOL(iget5_locked);
1037 * iget_locked - obtain an inode from a mounted file system
1038 * @sb: super block of file system
1039 * @ino: inode number to get
1041 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
1042 * the inode cache and if present it is returned with an increased reference
1043 * count. This is for file systems where the inode number is sufficient for
1044 * unique identification of an inode.
1046 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
1047 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
1048 * The file system gets to fill it in before unlocking it via
1049 * unlock_new_inode().
1051 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1053 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1054 struct inode *inode;
1056 inode = ifind_fast(sb, head, ino);
1060 * get_new_inode_fast() will do the right thing, re-trying the search
1061 * in case it had to block at any point.
1063 return get_new_inode_fast(sb, head, ino);
1065 EXPORT_SYMBOL(iget_locked);
1067 int insert_inode_locked(struct inode *inode)
1069 struct super_block *sb = inode->i_sb;
1070 ino_t ino = inode->i_ino;
1071 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1073 inode->i_state |= I_LOCK|I_NEW;
1075 struct hlist_node *node;
1076 struct inode *old = NULL;
1077 spin_lock(&inode_lock);
1078 hlist_for_each_entry(old, node, head, i_hash) {
1079 if (old->i_ino != ino)
1081 if (old->i_sb != sb)
1083 if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
1087 if (likely(!node)) {
1088 hlist_add_head(&inode->i_hash, head);
1089 spin_unlock(&inode_lock);
1093 spin_unlock(&inode_lock);
1095 if (unlikely(!hlist_unhashed(&old->i_hash))) {
1102 EXPORT_SYMBOL(insert_inode_locked);
1104 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1105 int (*test)(struct inode *, void *), void *data)
1107 struct super_block *sb = inode->i_sb;
1108 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1110 inode->i_state |= I_LOCK|I_NEW;
1113 struct hlist_node *node;
1114 struct inode *old = NULL;
1116 spin_lock(&inode_lock);
1117 hlist_for_each_entry(old, node, head, i_hash) {
1118 if (old->i_sb != sb)
1120 if (!test(old, data))
1122 if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))
1126 if (likely(!node)) {
1127 hlist_add_head(&inode->i_hash, head);
1128 spin_unlock(&inode_lock);
1132 spin_unlock(&inode_lock);
1134 if (unlikely(!hlist_unhashed(&old->i_hash))) {
1141 EXPORT_SYMBOL(insert_inode_locked4);
1144 * __insert_inode_hash - hash an inode
1145 * @inode: unhashed inode
1146 * @hashval: unsigned long value used to locate this object in the
1149 * Add an inode to the inode hash for this superblock.
1151 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
1153 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
1154 spin_lock(&inode_lock);
1155 hlist_add_head(&inode->i_hash, head);
1156 spin_unlock(&inode_lock);
1158 EXPORT_SYMBOL(__insert_inode_hash);
1161 * remove_inode_hash - remove an inode from the hash
1162 * @inode: inode to unhash
1164 * Remove an inode from the superblock.
1166 void remove_inode_hash(struct inode *inode)
1168 spin_lock(&inode_lock);
1169 hlist_del_init(&inode->i_hash);
1170 spin_unlock(&inode_lock);
1172 EXPORT_SYMBOL(remove_inode_hash);
1175 * Tell the filesystem that this inode is no longer of any interest and should
1176 * be completely destroyed.
1178 * We leave the inode in the inode hash table until *after* the filesystem's
1179 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1180 * instigate) will always find up-to-date information either in the hash or on
1183 * I_FREEING is set so that no-one will take a new reference to the inode while
1184 * it is being deleted.
1186 void generic_delete_inode(struct inode *inode)
1188 const struct super_operations *op = inode->i_sb->s_op;
1190 list_del_init(&inode->i_list);
1191 list_del_init(&inode->i_sb_list);
1192 WARN_ON(inode->i_state & I_NEW);
1193 inode->i_state |= I_FREEING;
1194 inodes_stat.nr_inodes--;
1195 spin_unlock(&inode_lock);
1197 security_inode_delete(inode);
1199 if (op->delete_inode) {
1200 void (*delete)(struct inode *) = op->delete_inode;
1201 if (!is_bad_inode(inode))
1203 /* Filesystems implementing their own
1204 * s_op->delete_inode are required to call
1205 * truncate_inode_pages and clear_inode()
1209 truncate_inode_pages(&inode->i_data, 0);
1212 spin_lock(&inode_lock);
1213 hlist_del_init(&inode->i_hash);
1214 spin_unlock(&inode_lock);
1215 wake_up_inode(inode);
1216 BUG_ON(inode->i_state != I_CLEAR);
1217 destroy_inode(inode);
1219 EXPORT_SYMBOL(generic_delete_inode);
1221 static void generic_forget_inode(struct inode *inode)
1223 struct super_block *sb = inode->i_sb;
1225 if (!hlist_unhashed(&inode->i_hash)) {
1226 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
1227 list_move(&inode->i_list, &inode_unused);
1228 inodes_stat.nr_unused++;
1229 if (sb->s_flags & MS_ACTIVE) {
1230 spin_unlock(&inode_lock);
1233 WARN_ON(inode->i_state & I_NEW);
1234 inode->i_state |= I_WILL_FREE;
1235 spin_unlock(&inode_lock);
1236 write_inode_now(inode, 1);
1237 spin_lock(&inode_lock);
1238 WARN_ON(inode->i_state & I_NEW);
1239 inode->i_state &= ~I_WILL_FREE;
1240 inodes_stat.nr_unused--;
1241 hlist_del_init(&inode->i_hash);
1243 list_del_init(&inode->i_list);
1244 list_del_init(&inode->i_sb_list);
1245 WARN_ON(inode->i_state & I_NEW);
1246 inode->i_state |= I_FREEING;
1247 inodes_stat.nr_inodes--;
1248 spin_unlock(&inode_lock);
1249 if (inode->i_data.nrpages)
1250 truncate_inode_pages(&inode->i_data, 0);
1252 wake_up_inode(inode);
1253 destroy_inode(inode);
1257 * Normal UNIX filesystem behaviour: delete the
1258 * inode when the usage count drops to zero, and
1261 void generic_drop_inode(struct inode *inode)
1263 if (!inode->i_nlink)
1264 generic_delete_inode(inode);
1266 generic_forget_inode(inode);
1268 EXPORT_SYMBOL_GPL(generic_drop_inode);
1271 * Called when we're dropping the last reference
1274 * Call the FS "drop()" function, defaulting to
1275 * the legacy UNIX filesystem behaviour..
1277 * NOTE! NOTE! NOTE! We're called with the inode lock
1278 * held, and the drop function is supposed to release
1281 static inline void iput_final(struct inode *inode)
1283 const struct super_operations *op = inode->i_sb->s_op;
1284 void (*drop)(struct inode *) = generic_drop_inode;
1286 if (op && op->drop_inode)
1287 drop = op->drop_inode;
1292 * iput - put an inode
1293 * @inode: inode to put
1295 * Puts an inode, dropping its usage count. If the inode use count hits
1296 * zero, the inode is then freed and may also be destroyed.
1298 * Consequently, iput() can sleep.
1300 void iput(struct inode *inode)
1303 BUG_ON(inode->i_state == I_CLEAR);
1305 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1309 EXPORT_SYMBOL(iput);
1312 * bmap - find a block number in a file
1313 * @inode: inode of file
1314 * @block: block to find
1316 * Returns the block number on the device holding the inode that
1317 * is the disk block number for the block of the file requested.
1318 * That is, asked for block 4 of inode 1 the function will return the
1319 * disk block relative to the disk start that holds that block of the
1322 sector_t bmap(struct inode *inode, sector_t block)
1325 if (inode->i_mapping->a_ops->bmap)
1326 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1329 EXPORT_SYMBOL(bmap);
1332 * With relative atime, only update atime if the previous atime is
1333 * earlier than either the ctime or mtime or if at least a day has
1334 * passed since the last atime update.
1336 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1337 struct timespec now)
1340 if (!(mnt->mnt_flags & MNT_RELATIME))
1343 * Is mtime younger than atime? If yes, update atime:
1345 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1348 * Is ctime younger than atime? If yes, update atime:
1350 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1354 * Is the previous atime value older than a day? If yes,
1357 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1360 * Good, we can skip the atime update:
1366 * touch_atime - update the access time
1367 * @mnt: mount the inode is accessed on
1368 * @dentry: dentry accessed
1370 * Update the accessed time on an inode and mark it for writeback.
1371 * This function automatically handles read only file systems and media,
1372 * as well as the "noatime" flag and inode specific "noatime" markers.
1374 void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1376 struct inode *inode = dentry->d_inode;
1377 struct timespec now;
1379 if (mnt_want_write(mnt))
1381 if (inode->i_flags & S_NOATIME)
1383 if (IS_NOATIME(inode))
1385 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1388 if (mnt->mnt_flags & MNT_NOATIME)
1390 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1393 now = current_fs_time(inode->i_sb);
1395 if (!relatime_need_update(mnt, inode, now))
1398 if (timespec_equal(&inode->i_atime, &now))
1401 inode->i_atime = now;
1402 mark_inode_dirty_sync(inode);
1404 mnt_drop_write(mnt);
1406 EXPORT_SYMBOL(touch_atime);
1409 * file_update_time - update mtime and ctime time
1410 * @file: file accessed
1412 * Update the mtime and ctime members of an inode and mark the inode
1413 * for writeback. Note that this function is meant exclusively for
1414 * usage in the file write path of filesystems, and filesystems may
1415 * choose to explicitly ignore update via this function with the
1416 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1417 * timestamps are handled by the server.
1420 void file_update_time(struct file *file)
1422 struct inode *inode = file->f_path.dentry->d_inode;
1423 struct timespec now;
1427 if (IS_NOCMTIME(inode))
1430 err = mnt_want_write_file(file);
1434 now = current_fs_time(inode->i_sb);
1435 if (!timespec_equal(&inode->i_mtime, &now)) {
1436 inode->i_mtime = now;
1440 if (!timespec_equal(&inode->i_ctime, &now)) {
1441 inode->i_ctime = now;
1445 if (IS_I_VERSION(inode)) {
1446 inode_inc_iversion(inode);
1451 mark_inode_dirty_sync(inode);
1452 mnt_drop_write(file->f_path.mnt);
1454 EXPORT_SYMBOL(file_update_time);
1456 int inode_needs_sync(struct inode *inode)
1460 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1464 EXPORT_SYMBOL(inode_needs_sync);
1466 int inode_wait(void *word)
1471 EXPORT_SYMBOL(inode_wait);
1474 * If we try to find an inode in the inode hash while it is being
1475 * deleted, we have to wait until the filesystem completes its
1476 * deletion before reporting that it isn't found. This function waits
1477 * until the deletion _might_ have completed. Callers are responsible
1478 * to recheck inode state.
1480 * It doesn't matter if I_LOCK is not set initially, a call to
1481 * wake_up_inode() after removing from the hash list will DTRT.
1483 * This is called with inode_lock held.
1485 static void __wait_on_freeing_inode(struct inode *inode)
1487 wait_queue_head_t *wq;
1488 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
1489 wq = bit_waitqueue(&inode->i_state, __I_LOCK);
1490 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1491 spin_unlock(&inode_lock);
1493 finish_wait(wq, &wait.wait);
1494 spin_lock(&inode_lock);
1497 static __initdata unsigned long ihash_entries;
1498 static int __init set_ihash_entries(char *str)
1502 ihash_entries = simple_strtoul(str, &str, 0);
1505 __setup("ihash_entries=", set_ihash_entries);
1508 * Initialize the waitqueues and inode hash table.
1510 void __init inode_init_early(void)
1514 /* If hashes are distributed across NUMA nodes, defer
1515 * hash allocation until vmalloc space is available.
1521 alloc_large_system_hash("Inode-cache",
1522 sizeof(struct hlist_head),
1530 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1531 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1534 void __init inode_init(void)
1538 /* inode slab cache */
1539 inode_cachep = kmem_cache_create("inode_cache",
1540 sizeof(struct inode),
1542 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1545 register_shrinker(&icache_shrinker);
1547 /* Hash may have been set up in inode_init_early */
1552 alloc_large_system_hash("Inode-cache",
1553 sizeof(struct hlist_head),
1561 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1562 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1565 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1567 inode->i_mode = mode;
1568 if (S_ISCHR(mode)) {
1569 inode->i_fop = &def_chr_fops;
1570 inode->i_rdev = rdev;
1571 } else if (S_ISBLK(mode)) {
1572 inode->i_fop = &def_blk_fops;
1573 inode->i_rdev = rdev;
1574 } else if (S_ISFIFO(mode))
1575 inode->i_fop = &def_fifo_fops;
1576 else if (S_ISSOCK(mode))
1577 inode->i_fop = &bad_sock_fops;
1579 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
1582 EXPORT_SYMBOL(init_special_inode);