2 * (C) 1997 Linus Torvalds
3 * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
5 #include <linux/export.h>
8 #include <linux/backing-dev.h>
9 #include <linux/hash.h>
10 #include <linux/swap.h>
11 #include <linux/security.h>
12 #include <linux/cdev.h>
13 #include <linux/bootmem.h>
14 #include <linux/fsnotify.h>
15 #include <linux/mount.h>
16 #include <linux/posix_acl.h>
17 #include <linux/prefetch.h>
18 #include <linux/buffer_head.h> /* for inode_has_buffers */
19 #include <linux/ratelimit.h>
20 #include <linux/list_lru.h>
24 * Inode locking rules:
26 * inode->i_lock protects:
27 * inode->i_state, inode->i_hash, __iget()
28 * Inode LRU list locks protect:
29 * inode->i_sb->s_inode_lru, inode->i_lru
30 * inode_sb_list_lock protects:
31 * sb->s_inodes, inode->i_sb_list
32 * bdi->wb.list_lock protects:
33 * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
34 * inode_hash_lock protects:
35 * inode_hashtable, inode->i_hash
41 * Inode LRU list locks
54 static unsigned int i_hash_mask __read_mostly;
55 static unsigned int i_hash_shift __read_mostly;
56 static struct hlist_head *inode_hashtable __read_mostly;
57 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
59 __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);
62 * Empty aops. Can be used for the cases where the user does not
63 * define any of the address_space operations.
65 const struct address_space_operations empty_aops = {
67 EXPORT_SYMBOL(empty_aops);
70 * Statistics gathering..
72 struct inodes_stat_t inodes_stat;
74 static DEFINE_PER_CPU(unsigned long, nr_inodes);
75 static DEFINE_PER_CPU(unsigned long, nr_unused);
77 static struct kmem_cache *inode_cachep __read_mostly;
79 static long get_nr_inodes(void)
83 for_each_possible_cpu(i)
84 sum += per_cpu(nr_inodes, i);
85 return sum < 0 ? 0 : sum;
88 static inline long get_nr_inodes_unused(void)
92 for_each_possible_cpu(i)
93 sum += per_cpu(nr_unused, i);
94 return sum < 0 ? 0 : sum;
97 long get_nr_dirty_inodes(void)
99 /* not actually dirty inodes, but a wild approximation */
100 long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
101 return nr_dirty > 0 ? nr_dirty : 0;
105 * Handle nr_inode sysctl
108 int proc_nr_inodes(struct ctl_table *table, int write,
109 void __user *buffer, size_t *lenp, loff_t *ppos)
111 inodes_stat.nr_inodes = get_nr_inodes();
112 inodes_stat.nr_unused = get_nr_inodes_unused();
113 return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
117 static int no_open(struct inode *inode, struct file *file)
123 * inode_init_always - perform inode structure intialisation
124 * @sb: superblock inode belongs to
125 * @inode: inode to initialise
127 * These are initializations that need to be done on every inode
128 * allocation as the fields are not initialised by slab allocation.
130 int inode_init_always(struct super_block *sb, struct inode *inode)
132 static const struct inode_operations empty_iops;
133 static const struct file_operations no_open_fops = {.open = no_open};
134 struct address_space *const mapping = &inode->i_data;
137 inode->i_blkbits = sb->s_blocksize_bits;
139 atomic_set(&inode->i_count, 1);
140 inode->i_op = &empty_iops;
141 inode->i_fop = &no_open_fops;
142 inode->__i_nlink = 1;
143 inode->i_opflags = 0;
144 i_uid_write(inode, 0);
145 i_gid_write(inode, 0);
146 atomic_set(&inode->i_writecount, 0);
150 inode->i_generation = 0;
151 inode->i_pipe = NULL;
152 inode->i_bdev = NULL;
153 inode->i_cdev = NULL;
155 inode->dirtied_when = 0;
157 if (security_inode_alloc(inode))
159 spin_lock_init(&inode->i_lock);
160 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
162 mutex_init(&inode->i_mutex);
163 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
165 atomic_set(&inode->i_dio_count, 0);
167 mapping->a_ops = &empty_aops;
168 mapping->host = inode;
170 atomic_set(&mapping->i_mmap_writable, 0);
171 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
172 mapping->private_data = NULL;
173 mapping->backing_dev_info = &default_backing_dev_info;
174 mapping->writeback_index = 0;
177 * If the block_device provides a backing_dev_info for client
178 * inodes then use that. Otherwise the inode share the bdev's
182 struct backing_dev_info *bdi;
184 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
185 mapping->backing_dev_info = bdi;
187 inode->i_private = NULL;
188 inode->i_mapping = mapping;
189 INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
190 #ifdef CONFIG_FS_POSIX_ACL
191 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
194 #ifdef CONFIG_FSNOTIFY
195 inode->i_fsnotify_mask = 0;
197 inode->i_flctx = NULL;
198 this_cpu_inc(nr_inodes);
204 EXPORT_SYMBOL(inode_init_always);
206 static struct inode *alloc_inode(struct super_block *sb)
210 if (sb->s_op->alloc_inode)
211 inode = sb->s_op->alloc_inode(sb);
213 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
218 if (unlikely(inode_init_always(sb, inode))) {
219 if (inode->i_sb->s_op->destroy_inode)
220 inode->i_sb->s_op->destroy_inode(inode);
222 kmem_cache_free(inode_cachep, inode);
229 void free_inode_nonrcu(struct inode *inode)
231 kmem_cache_free(inode_cachep, inode);
233 EXPORT_SYMBOL(free_inode_nonrcu);
235 void __destroy_inode(struct inode *inode)
237 BUG_ON(inode_has_buffers(inode));
238 security_inode_free(inode);
239 fsnotify_inode_delete(inode);
240 locks_free_lock_context(inode->i_flctx);
241 if (!inode->i_nlink) {
242 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
243 atomic_long_dec(&inode->i_sb->s_remove_count);
246 #ifdef CONFIG_FS_POSIX_ACL
247 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
248 posix_acl_release(inode->i_acl);
249 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
250 posix_acl_release(inode->i_default_acl);
252 this_cpu_dec(nr_inodes);
254 EXPORT_SYMBOL(__destroy_inode);
256 static void i_callback(struct rcu_head *head)
258 struct inode *inode = container_of(head, struct inode, i_rcu);
259 kmem_cache_free(inode_cachep, inode);
262 static void destroy_inode(struct inode *inode)
264 BUG_ON(!list_empty(&inode->i_lru));
265 __destroy_inode(inode);
266 if (inode->i_sb->s_op->destroy_inode)
267 inode->i_sb->s_op->destroy_inode(inode);
269 call_rcu(&inode->i_rcu, i_callback);
273 * drop_nlink - directly drop an inode's link count
276 * This is a low-level filesystem helper to replace any
277 * direct filesystem manipulation of i_nlink. In cases
278 * where we are attempting to track writes to the
279 * filesystem, a decrement to zero means an imminent
280 * write when the file is truncated and actually unlinked
283 void drop_nlink(struct inode *inode)
285 WARN_ON(inode->i_nlink == 0);
288 atomic_long_inc(&inode->i_sb->s_remove_count);
290 EXPORT_SYMBOL(drop_nlink);
293 * clear_nlink - directly zero an inode's link count
296 * This is a low-level filesystem helper to replace any
297 * direct filesystem manipulation of i_nlink. See
298 * drop_nlink() for why we care about i_nlink hitting zero.
300 void clear_nlink(struct inode *inode)
302 if (inode->i_nlink) {
303 inode->__i_nlink = 0;
304 atomic_long_inc(&inode->i_sb->s_remove_count);
307 EXPORT_SYMBOL(clear_nlink);
310 * set_nlink - directly set an inode's link count
312 * @nlink: new nlink (should be non-zero)
314 * This is a low-level filesystem helper to replace any
315 * direct filesystem manipulation of i_nlink.
317 void set_nlink(struct inode *inode, unsigned int nlink)
322 /* Yes, some filesystems do change nlink from zero to one */
323 if (inode->i_nlink == 0)
324 atomic_long_dec(&inode->i_sb->s_remove_count);
326 inode->__i_nlink = nlink;
329 EXPORT_SYMBOL(set_nlink);
332 * inc_nlink - directly increment an inode's link count
335 * This is a low-level filesystem helper to replace any
336 * direct filesystem manipulation of i_nlink. Currently,
337 * it is only here for parity with dec_nlink().
339 void inc_nlink(struct inode *inode)
341 if (unlikely(inode->i_nlink == 0)) {
342 WARN_ON(!(inode->i_state & I_LINKABLE));
343 atomic_long_dec(&inode->i_sb->s_remove_count);
348 EXPORT_SYMBOL(inc_nlink);
350 void address_space_init_once(struct address_space *mapping)
352 memset(mapping, 0, sizeof(*mapping));
353 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
354 spin_lock_init(&mapping->tree_lock);
355 init_rwsem(&mapping->i_mmap_rwsem);
356 INIT_LIST_HEAD(&mapping->private_list);
357 spin_lock_init(&mapping->private_lock);
358 mapping->i_mmap = RB_ROOT;
360 EXPORT_SYMBOL(address_space_init_once);
363 * These are initializations that only need to be done
364 * once, because the fields are idempotent across use
365 * of the inode, so let the slab aware of that.
367 void inode_init_once(struct inode *inode)
369 memset(inode, 0, sizeof(*inode));
370 INIT_HLIST_NODE(&inode->i_hash);
371 INIT_LIST_HEAD(&inode->i_devices);
372 INIT_LIST_HEAD(&inode->i_wb_list);
373 INIT_LIST_HEAD(&inode->i_lru);
374 address_space_init_once(&inode->i_data);
375 i_size_ordered_init(inode);
376 #ifdef CONFIG_FSNOTIFY
377 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
380 EXPORT_SYMBOL(inode_init_once);
382 static void init_once(void *foo)
384 struct inode *inode = (struct inode *) foo;
386 inode_init_once(inode);
390 * inode->i_lock must be held
392 void __iget(struct inode *inode)
394 atomic_inc(&inode->i_count);
398 * get additional reference to inode; caller must already hold one.
400 void ihold(struct inode *inode)
402 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
404 EXPORT_SYMBOL(ihold);
406 static void inode_lru_list_add(struct inode *inode)
408 if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
409 this_cpu_inc(nr_unused);
413 * Add inode to LRU if needed (inode is unused and clean).
415 * Needs inode->i_lock held.
417 void inode_add_lru(struct inode *inode)
419 if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) &&
420 !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE)
421 inode_lru_list_add(inode);
425 static void inode_lru_list_del(struct inode *inode)
428 if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
429 this_cpu_dec(nr_unused);
433 * inode_sb_list_add - add inode to the superblock list of inodes
434 * @inode: inode to add
436 void inode_sb_list_add(struct inode *inode)
438 spin_lock(&inode_sb_list_lock);
439 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
440 spin_unlock(&inode_sb_list_lock);
442 EXPORT_SYMBOL_GPL(inode_sb_list_add);
444 static inline void inode_sb_list_del(struct inode *inode)
446 if (!list_empty(&inode->i_sb_list)) {
447 spin_lock(&inode_sb_list_lock);
448 list_del_init(&inode->i_sb_list);
449 spin_unlock(&inode_sb_list_lock);
453 static unsigned long hash(struct super_block *sb, unsigned long hashval)
457 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
459 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
460 return tmp & i_hash_mask;
464 * __insert_inode_hash - hash an inode
465 * @inode: unhashed inode
466 * @hashval: unsigned long value used to locate this object in the
469 * Add an inode to the inode hash for this superblock.
471 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
473 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
475 spin_lock(&inode_hash_lock);
476 spin_lock(&inode->i_lock);
477 hlist_add_head(&inode->i_hash, b);
478 spin_unlock(&inode->i_lock);
479 spin_unlock(&inode_hash_lock);
481 EXPORT_SYMBOL(__insert_inode_hash);
484 * __remove_inode_hash - remove an inode from the hash
485 * @inode: inode to unhash
487 * Remove an inode from the superblock.
489 void __remove_inode_hash(struct inode *inode)
491 spin_lock(&inode_hash_lock);
492 spin_lock(&inode->i_lock);
493 hlist_del_init(&inode->i_hash);
494 spin_unlock(&inode->i_lock);
495 spin_unlock(&inode_hash_lock);
497 EXPORT_SYMBOL(__remove_inode_hash);
499 void clear_inode(struct inode *inode)
503 * We have to cycle tree_lock here because reclaim can be still in the
504 * process of removing the last page (in __delete_from_page_cache())
505 * and we must not free mapping under it.
507 spin_lock_irq(&inode->i_data.tree_lock);
508 BUG_ON(inode->i_data.nrpages);
509 BUG_ON(inode->i_data.nrshadows);
510 spin_unlock_irq(&inode->i_data.tree_lock);
511 BUG_ON(!list_empty(&inode->i_data.private_list));
512 BUG_ON(!(inode->i_state & I_FREEING));
513 BUG_ON(inode->i_state & I_CLEAR);
514 /* don't need i_lock here, no concurrent mods to i_state */
515 inode->i_state = I_FREEING | I_CLEAR;
517 EXPORT_SYMBOL(clear_inode);
520 * Free the inode passed in, removing it from the lists it is still connected
521 * to. We remove any pages still attached to the inode and wait for any IO that
522 * is still in progress before finally destroying the inode.
524 * An inode must already be marked I_FREEING so that we avoid the inode being
525 * moved back onto lists if we race with other code that manipulates the lists
526 * (e.g. writeback_single_inode). The caller is responsible for setting this.
528 * An inode must already be removed from the LRU list before being evicted from
529 * the cache. This should occur atomically with setting the I_FREEING state
530 * flag, so no inodes here should ever be on the LRU when being evicted.
532 static void evict(struct inode *inode)
534 const struct super_operations *op = inode->i_sb->s_op;
536 BUG_ON(!(inode->i_state & I_FREEING));
537 BUG_ON(!list_empty(&inode->i_lru));
539 if (!list_empty(&inode->i_wb_list))
540 inode_wb_list_del(inode);
542 inode_sb_list_del(inode);
545 * Wait for flusher thread to be done with the inode so that filesystem
546 * does not start destroying it while writeback is still running. Since
547 * the inode has I_FREEING set, flusher thread won't start new work on
548 * the inode. We just have to wait for running writeback to finish.
550 inode_wait_for_writeback(inode);
552 if (op->evict_inode) {
553 op->evict_inode(inode);
555 truncate_inode_pages_final(&inode->i_data);
558 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
560 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
563 remove_inode_hash(inode);
565 spin_lock(&inode->i_lock);
566 wake_up_bit(&inode->i_state, __I_NEW);
567 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
568 spin_unlock(&inode->i_lock);
570 destroy_inode(inode);
574 * dispose_list - dispose of the contents of a local list
575 * @head: the head of the list to free
577 * Dispose-list gets a local list with local inodes in it, so it doesn't
578 * need to worry about list corruption and SMP locks.
580 static void dispose_list(struct list_head *head)
582 while (!list_empty(head)) {
585 inode = list_first_entry(head, struct inode, i_lru);
586 list_del_init(&inode->i_lru);
593 * evict_inodes - evict all evictable inodes for a superblock
594 * @sb: superblock to operate on
596 * Make sure that no inodes with zero refcount are retained. This is
597 * called by superblock shutdown after having MS_ACTIVE flag removed,
598 * so any inode reaching zero refcount during or after that call will
599 * be immediately evicted.
601 void evict_inodes(struct super_block *sb)
603 struct inode *inode, *next;
606 spin_lock(&inode_sb_list_lock);
607 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
608 if (atomic_read(&inode->i_count))
611 spin_lock(&inode->i_lock);
612 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
613 spin_unlock(&inode->i_lock);
617 inode->i_state |= I_FREEING;
618 inode_lru_list_del(inode);
619 spin_unlock(&inode->i_lock);
620 list_add(&inode->i_lru, &dispose);
622 spin_unlock(&inode_sb_list_lock);
624 dispose_list(&dispose);
628 * invalidate_inodes - attempt to free all inodes on a superblock
629 * @sb: superblock to operate on
630 * @kill_dirty: flag to guide handling of dirty inodes
632 * Attempts to free all inodes for a given superblock. If there were any
633 * busy inodes return a non-zero value, else zero.
634 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
637 int invalidate_inodes(struct super_block *sb, bool kill_dirty)
640 struct inode *inode, *next;
643 spin_lock(&inode_sb_list_lock);
644 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
645 spin_lock(&inode->i_lock);
646 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
647 spin_unlock(&inode->i_lock);
650 if (inode->i_state & I_DIRTY && !kill_dirty) {
651 spin_unlock(&inode->i_lock);
655 if (atomic_read(&inode->i_count)) {
656 spin_unlock(&inode->i_lock);
661 inode->i_state |= I_FREEING;
662 inode_lru_list_del(inode);
663 spin_unlock(&inode->i_lock);
664 list_add(&inode->i_lru, &dispose);
666 spin_unlock(&inode_sb_list_lock);
668 dispose_list(&dispose);
674 * Isolate the inode from the LRU in preparation for freeing it.
676 * Any inodes which are pinned purely because of attached pagecache have their
677 * pagecache removed. If the inode has metadata buffers attached to
678 * mapping->private_list then try to remove them.
680 * If the inode has the I_REFERENCED flag set, then it means that it has been
681 * used recently - the flag is set in iput_final(). When we encounter such an
682 * inode, clear the flag and move it to the back of the LRU so it gets another
683 * pass through the LRU before it gets reclaimed. This is necessary because of
684 * the fact we are doing lazy LRU updates to minimise lock contention so the
685 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
686 * with this flag set because they are the inodes that are out of order.
688 static enum lru_status inode_lru_isolate(struct list_head *item,
689 struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
691 struct list_head *freeable = arg;
692 struct inode *inode = container_of(item, struct inode, i_lru);
695 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
696 * If we fail to get the lock, just skip it.
698 if (!spin_trylock(&inode->i_lock))
702 * Referenced or dirty inodes are still in use. Give them another pass
703 * through the LRU as we canot reclaim them now.
705 if (atomic_read(&inode->i_count) ||
706 (inode->i_state & ~I_REFERENCED)) {
707 list_lru_isolate(lru, &inode->i_lru);
708 spin_unlock(&inode->i_lock);
709 this_cpu_dec(nr_unused);
713 /* recently referenced inodes get one more pass */
714 if (inode->i_state & I_REFERENCED) {
715 inode->i_state &= ~I_REFERENCED;
716 spin_unlock(&inode->i_lock);
720 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
722 spin_unlock(&inode->i_lock);
723 spin_unlock(lru_lock);
724 if (remove_inode_buffers(inode)) {
726 reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
727 if (current_is_kswapd())
728 __count_vm_events(KSWAPD_INODESTEAL, reap);
730 __count_vm_events(PGINODESTEAL, reap);
731 if (current->reclaim_state)
732 current->reclaim_state->reclaimed_slab += reap;
739 WARN_ON(inode->i_state & I_NEW);
740 inode->i_state |= I_FREEING;
741 list_lru_isolate_move(lru, &inode->i_lru, freeable);
742 spin_unlock(&inode->i_lock);
744 this_cpu_dec(nr_unused);
749 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
750 * This is called from the superblock shrinker function with a number of inodes
751 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
752 * then are freed outside inode_lock by dispose_list().
754 long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
759 freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
760 inode_lru_isolate, &freeable);
761 dispose_list(&freeable);
765 static void __wait_on_freeing_inode(struct inode *inode);
767 * Called with the inode lock held.
769 static struct inode *find_inode(struct super_block *sb,
770 struct hlist_head *head,
771 int (*test)(struct inode *, void *),
774 struct inode *inode = NULL;
777 hlist_for_each_entry(inode, head, i_hash) {
778 if (inode->i_sb != sb)
780 if (!test(inode, data))
782 spin_lock(&inode->i_lock);
783 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
784 __wait_on_freeing_inode(inode);
788 spin_unlock(&inode->i_lock);
795 * find_inode_fast is the fast path version of find_inode, see the comment at
796 * iget_locked for details.
798 static struct inode *find_inode_fast(struct super_block *sb,
799 struct hlist_head *head, unsigned long ino)
801 struct inode *inode = NULL;
804 hlist_for_each_entry(inode, head, i_hash) {
805 if (inode->i_ino != ino)
807 if (inode->i_sb != sb)
809 spin_lock(&inode->i_lock);
810 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
811 __wait_on_freeing_inode(inode);
815 spin_unlock(&inode->i_lock);
822 * Each cpu owns a range of LAST_INO_BATCH numbers.
823 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
824 * to renew the exhausted range.
826 * This does not significantly increase overflow rate because every CPU can
827 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
828 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
829 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
830 * overflow rate by 2x, which does not seem too significant.
832 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
833 * error if st_ino won't fit in target struct field. Use 32bit counter
834 * here to attempt to avoid that.
836 #define LAST_INO_BATCH 1024
837 static DEFINE_PER_CPU(unsigned int, last_ino);
839 unsigned int get_next_ino(void)
841 unsigned int *p = &get_cpu_var(last_ino);
842 unsigned int res = *p;
845 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
846 static atomic_t shared_last_ino;
847 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
849 res = next - LAST_INO_BATCH;
854 put_cpu_var(last_ino);
857 EXPORT_SYMBOL(get_next_ino);
860 * new_inode_pseudo - obtain an inode
863 * Allocates a new inode for given superblock.
864 * Inode wont be chained in superblock s_inodes list
866 * - fs can't be unmount
867 * - quotas, fsnotify, writeback can't work
869 struct inode *new_inode_pseudo(struct super_block *sb)
871 struct inode *inode = alloc_inode(sb);
874 spin_lock(&inode->i_lock);
876 spin_unlock(&inode->i_lock);
877 INIT_LIST_HEAD(&inode->i_sb_list);
883 * new_inode - obtain an inode
886 * Allocates a new inode for given superblock. The default gfp_mask
887 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
888 * If HIGHMEM pages are unsuitable or it is known that pages allocated
889 * for the page cache are not reclaimable or migratable,
890 * mapping_set_gfp_mask() must be called with suitable flags on the
891 * newly created inode's mapping
894 struct inode *new_inode(struct super_block *sb)
898 spin_lock_prefetch(&inode_sb_list_lock);
900 inode = new_inode_pseudo(sb);
902 inode_sb_list_add(inode);
905 EXPORT_SYMBOL(new_inode);
907 #ifdef CONFIG_DEBUG_LOCK_ALLOC
908 void lockdep_annotate_inode_mutex_key(struct inode *inode)
910 if (S_ISDIR(inode->i_mode)) {
911 struct file_system_type *type = inode->i_sb->s_type;
913 /* Set new key only if filesystem hasn't already changed it */
914 if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) {
916 * ensure nobody is actually holding i_mutex
918 mutex_destroy(&inode->i_mutex);
919 mutex_init(&inode->i_mutex);
920 lockdep_set_class(&inode->i_mutex,
921 &type->i_mutex_dir_key);
925 EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
929 * unlock_new_inode - clear the I_NEW state and wake up any waiters
930 * @inode: new inode to unlock
932 * Called when the inode is fully initialised to clear the new state of the
933 * inode and wake up anyone waiting for the inode to finish initialisation.
935 void unlock_new_inode(struct inode *inode)
937 lockdep_annotate_inode_mutex_key(inode);
938 spin_lock(&inode->i_lock);
939 WARN_ON(!(inode->i_state & I_NEW));
940 inode->i_state &= ~I_NEW;
942 wake_up_bit(&inode->i_state, __I_NEW);
943 spin_unlock(&inode->i_lock);
945 EXPORT_SYMBOL(unlock_new_inode);
948 * lock_two_nondirectories - take two i_mutexes on non-directory objects
950 * Lock any non-NULL argument that is not a directory.
951 * Zero, one or two objects may be locked by this function.
953 * @inode1: first inode to lock
954 * @inode2: second inode to lock
956 void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
959 swap(inode1, inode2);
961 if (inode1 && !S_ISDIR(inode1->i_mode))
962 mutex_lock(&inode1->i_mutex);
963 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
964 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
966 EXPORT_SYMBOL(lock_two_nondirectories);
969 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
970 * @inode1: first inode to unlock
971 * @inode2: second inode to unlock
973 void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
975 if (inode1 && !S_ISDIR(inode1->i_mode))
976 mutex_unlock(&inode1->i_mutex);
977 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
978 mutex_unlock(&inode2->i_mutex);
980 EXPORT_SYMBOL(unlock_two_nondirectories);
983 * iget5_locked - obtain an inode from a mounted file system
984 * @sb: super block of file system
985 * @hashval: hash value (usually inode number) to get
986 * @test: callback used for comparisons between inodes
987 * @set: callback used to initialize a new struct inode
988 * @data: opaque data pointer to pass to @test and @set
990 * Search for the inode specified by @hashval and @data in the inode cache,
991 * and if present it is return it with an increased reference count. This is
992 * a generalized version of iget_locked() for file systems where the inode
993 * number is not sufficient for unique identification of an inode.
995 * If the inode is not in cache, allocate a new inode and return it locked,
996 * hashed, and with the I_NEW flag set. The file system gets to fill it in
997 * before unlocking it via unlock_new_inode().
999 * Note both @test and @set are called with the inode_hash_lock held, so can't
1002 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1003 int (*test)(struct inode *, void *),
1004 int (*set)(struct inode *, void *), void *data)
1006 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1007 struct inode *inode;
1009 spin_lock(&inode_hash_lock);
1010 inode = find_inode(sb, head, test, data);
1011 spin_unlock(&inode_hash_lock);
1014 wait_on_inode(inode);
1018 inode = alloc_inode(sb);
1022 spin_lock(&inode_hash_lock);
1023 /* We released the lock, so.. */
1024 old = find_inode(sb, head, test, data);
1026 if (set(inode, data))
1029 spin_lock(&inode->i_lock);
1030 inode->i_state = I_NEW;
1031 hlist_add_head(&inode->i_hash, head);
1032 spin_unlock(&inode->i_lock);
1033 inode_sb_list_add(inode);
1034 spin_unlock(&inode_hash_lock);
1036 /* Return the locked inode with I_NEW set, the
1037 * caller is responsible for filling in the contents
1043 * Uhhuh, somebody else created the same inode under
1044 * us. Use the old inode instead of the one we just
1047 spin_unlock(&inode_hash_lock);
1048 destroy_inode(inode);
1050 wait_on_inode(inode);
1055 spin_unlock(&inode_hash_lock);
1056 destroy_inode(inode);
1059 EXPORT_SYMBOL(iget5_locked);
1062 * iget_locked - obtain an inode from a mounted file system
1063 * @sb: super block of file system
1064 * @ino: inode number to get
1066 * Search for the inode specified by @ino in the inode cache and if present
1067 * return it with an increased reference count. This is for file systems
1068 * where the inode number is sufficient for unique identification of an inode.
1070 * If the inode is not in cache, allocate a new inode and return it locked,
1071 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1072 * before unlocking it via unlock_new_inode().
1074 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1076 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1077 struct inode *inode;
1079 spin_lock(&inode_hash_lock);
1080 inode = find_inode_fast(sb, head, ino);
1081 spin_unlock(&inode_hash_lock);
1083 wait_on_inode(inode);
1087 inode = alloc_inode(sb);
1091 spin_lock(&inode_hash_lock);
1092 /* We released the lock, so.. */
1093 old = find_inode_fast(sb, head, ino);
1096 spin_lock(&inode->i_lock);
1097 inode->i_state = I_NEW;
1098 hlist_add_head(&inode->i_hash, head);
1099 spin_unlock(&inode->i_lock);
1100 inode_sb_list_add(inode);
1101 spin_unlock(&inode_hash_lock);
1103 /* Return the locked inode with I_NEW set, the
1104 * caller is responsible for filling in the contents
1110 * Uhhuh, somebody else created the same inode under
1111 * us. Use the old inode instead of the one we just
1114 spin_unlock(&inode_hash_lock);
1115 destroy_inode(inode);
1117 wait_on_inode(inode);
1121 EXPORT_SYMBOL(iget_locked);
1124 * search the inode cache for a matching inode number.
1125 * If we find one, then the inode number we are trying to
1126 * allocate is not unique and so we should not use it.
1128 * Returns 1 if the inode number is unique, 0 if it is not.
1130 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1132 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1133 struct inode *inode;
1135 spin_lock(&inode_hash_lock);
1136 hlist_for_each_entry(inode, b, i_hash) {
1137 if (inode->i_ino == ino && inode->i_sb == sb) {
1138 spin_unlock(&inode_hash_lock);
1142 spin_unlock(&inode_hash_lock);
1148 * iunique - get a unique inode number
1150 * @max_reserved: highest reserved inode number
1152 * Obtain an inode number that is unique on the system for a given
1153 * superblock. This is used by file systems that have no natural
1154 * permanent inode numbering system. An inode number is returned that
1155 * is higher than the reserved limit but unique.
1158 * With a large number of inodes live on the file system this function
1159 * currently becomes quite slow.
1161 ino_t iunique(struct super_block *sb, ino_t max_reserved)
1164 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1165 * error if st_ino won't fit in target struct field. Use 32bit counter
1166 * here to attempt to avoid that.
1168 static DEFINE_SPINLOCK(iunique_lock);
1169 static unsigned int counter;
1172 spin_lock(&iunique_lock);
1174 if (counter <= max_reserved)
1175 counter = max_reserved + 1;
1177 } while (!test_inode_iunique(sb, res));
1178 spin_unlock(&iunique_lock);
1182 EXPORT_SYMBOL(iunique);
1184 struct inode *igrab(struct inode *inode)
1186 spin_lock(&inode->i_lock);
1187 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1189 spin_unlock(&inode->i_lock);
1191 spin_unlock(&inode->i_lock);
1193 * Handle the case where s_op->clear_inode is not been
1194 * called yet, and somebody is calling igrab
1195 * while the inode is getting freed.
1201 EXPORT_SYMBOL(igrab);
1204 * ilookup5_nowait - search for an inode in the inode cache
1205 * @sb: super block of file system to search
1206 * @hashval: hash value (usually inode number) to search for
1207 * @test: callback used for comparisons between inodes
1208 * @data: opaque data pointer to pass to @test
1210 * Search for the inode specified by @hashval and @data in the inode cache.
1211 * If the inode is in the cache, the inode is returned with an incremented
1214 * Note: I_NEW is not waited upon so you have to be very careful what you do
1215 * with the returned inode. You probably should be using ilookup5() instead.
1217 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1219 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1220 int (*test)(struct inode *, void *), void *data)
1222 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1223 struct inode *inode;
1225 spin_lock(&inode_hash_lock);
1226 inode = find_inode(sb, head, test, data);
1227 spin_unlock(&inode_hash_lock);
1231 EXPORT_SYMBOL(ilookup5_nowait);
1234 * ilookup5 - search for an inode in the inode cache
1235 * @sb: super block of file system to search
1236 * @hashval: hash value (usually inode number) to search for
1237 * @test: callback used for comparisons between inodes
1238 * @data: opaque data pointer to pass to @test
1240 * Search for the inode specified by @hashval and @data in the inode cache,
1241 * and if the inode is in the cache, return the inode with an incremented
1242 * reference count. Waits on I_NEW before returning the inode.
1243 * returned with an incremented reference count.
1245 * This is a generalized version of ilookup() for file systems where the
1246 * inode number is not sufficient for unique identification of an inode.
1248 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1250 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1251 int (*test)(struct inode *, void *), void *data)
1253 struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
1256 wait_on_inode(inode);
1259 EXPORT_SYMBOL(ilookup5);
1262 * ilookup - search for an inode in the inode cache
1263 * @sb: super block of file system to search
1264 * @ino: inode number to search for
1266 * Search for the inode @ino in the inode cache, and if the inode is in the
1267 * cache, the inode is returned with an incremented reference count.
1269 struct inode *ilookup(struct super_block *sb, unsigned long ino)
1271 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1272 struct inode *inode;
1274 spin_lock(&inode_hash_lock);
1275 inode = find_inode_fast(sb, head, ino);
1276 spin_unlock(&inode_hash_lock);
1279 wait_on_inode(inode);
1282 EXPORT_SYMBOL(ilookup);
1284 int insert_inode_locked(struct inode *inode)
1286 struct super_block *sb = inode->i_sb;
1287 ino_t ino = inode->i_ino;
1288 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1291 struct inode *old = NULL;
1292 spin_lock(&inode_hash_lock);
1293 hlist_for_each_entry(old, head, i_hash) {
1294 if (old->i_ino != ino)
1296 if (old->i_sb != sb)
1298 spin_lock(&old->i_lock);
1299 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1300 spin_unlock(&old->i_lock);
1306 spin_lock(&inode->i_lock);
1307 inode->i_state |= I_NEW;
1308 hlist_add_head(&inode->i_hash, head);
1309 spin_unlock(&inode->i_lock);
1310 spin_unlock(&inode_hash_lock);
1314 spin_unlock(&old->i_lock);
1315 spin_unlock(&inode_hash_lock);
1317 if (unlikely(!inode_unhashed(old))) {
1324 EXPORT_SYMBOL(insert_inode_locked);
1326 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1327 int (*test)(struct inode *, void *), void *data)
1329 struct super_block *sb = inode->i_sb;
1330 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1333 struct inode *old = NULL;
1335 spin_lock(&inode_hash_lock);
1336 hlist_for_each_entry(old, head, i_hash) {
1337 if (old->i_sb != sb)
1339 if (!test(old, data))
1341 spin_lock(&old->i_lock);
1342 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1343 spin_unlock(&old->i_lock);
1349 spin_lock(&inode->i_lock);
1350 inode->i_state |= I_NEW;
1351 hlist_add_head(&inode->i_hash, head);
1352 spin_unlock(&inode->i_lock);
1353 spin_unlock(&inode_hash_lock);
1357 spin_unlock(&old->i_lock);
1358 spin_unlock(&inode_hash_lock);
1360 if (unlikely(!inode_unhashed(old))) {
1367 EXPORT_SYMBOL(insert_inode_locked4);
1370 int generic_delete_inode(struct inode *inode)
1374 EXPORT_SYMBOL(generic_delete_inode);
1377 * Called when we're dropping the last reference
1380 * Call the FS "drop_inode()" function, defaulting to
1381 * the legacy UNIX filesystem behaviour. If it tells
1382 * us to evict inode, do so. Otherwise, retain inode
1383 * in cache if fs is alive, sync and evict if fs is
1386 static void iput_final(struct inode *inode)
1388 struct super_block *sb = inode->i_sb;
1389 const struct super_operations *op = inode->i_sb->s_op;
1392 WARN_ON(inode->i_state & I_NEW);
1395 drop = op->drop_inode(inode);
1397 drop = generic_drop_inode(inode);
1399 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1400 inode->i_state |= I_REFERENCED;
1401 inode_add_lru(inode);
1402 spin_unlock(&inode->i_lock);
1407 inode->i_state |= I_WILL_FREE;
1408 spin_unlock(&inode->i_lock);
1409 write_inode_now(inode, 1);
1410 spin_lock(&inode->i_lock);
1411 WARN_ON(inode->i_state & I_NEW);
1412 inode->i_state &= ~I_WILL_FREE;
1415 inode->i_state |= I_FREEING;
1416 if (!list_empty(&inode->i_lru))
1417 inode_lru_list_del(inode);
1418 spin_unlock(&inode->i_lock);
1424 * iput - put an inode
1425 * @inode: inode to put
1427 * Puts an inode, dropping its usage count. If the inode use count hits
1428 * zero, the inode is then freed and may also be destroyed.
1430 * Consequently, iput() can sleep.
1432 void iput(struct inode *inode)
1435 BUG_ON(inode->i_state & I_CLEAR);
1437 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
1441 EXPORT_SYMBOL(iput);
1444 * bmap - find a block number in a file
1445 * @inode: inode of file
1446 * @block: block to find
1448 * Returns the block number on the device holding the inode that
1449 * is the disk block number for the block of the file requested.
1450 * That is, asked for block 4 of inode 1 the function will return the
1451 * disk block relative to the disk start that holds that block of the
1454 sector_t bmap(struct inode *inode, sector_t block)
1457 if (inode->i_mapping->a_ops->bmap)
1458 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1461 EXPORT_SYMBOL(bmap);
1464 * With relative atime, only update atime if the previous atime is
1465 * earlier than either the ctime or mtime or if at least a day has
1466 * passed since the last atime update.
1468 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1469 struct timespec now)
1472 if (!(mnt->mnt_flags & MNT_RELATIME))
1475 * Is mtime younger than atime? If yes, update atime:
1477 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1480 * Is ctime younger than atime? If yes, update atime:
1482 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1486 * Is the previous atime value older than a day? If yes,
1489 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1492 * Good, we can skip the atime update:
1498 * This does the actual work of updating an inodes time or version. Must have
1499 * had called mnt_want_write() before calling this.
1501 static int update_time(struct inode *inode, struct timespec *time, int flags)
1503 if (inode->i_op->update_time)
1504 return inode->i_op->update_time(inode, time, flags);
1506 if (flags & S_ATIME)
1507 inode->i_atime = *time;
1508 if (flags & S_VERSION)
1509 inode_inc_iversion(inode);
1510 if (flags & S_CTIME)
1511 inode->i_ctime = *time;
1512 if (flags & S_MTIME)
1513 inode->i_mtime = *time;
1514 mark_inode_dirty_sync(inode);
1519 * touch_atime - update the access time
1520 * @path: the &struct path to update
1522 * Update the accessed time on an inode and mark it for writeback.
1523 * This function automatically handles read only file systems and media,
1524 * as well as the "noatime" flag and inode specific "noatime" markers.
1526 void touch_atime(const struct path *path)
1528 struct vfsmount *mnt = path->mnt;
1529 struct inode *inode = path->dentry->d_inode;
1530 struct timespec now;
1532 if (inode->i_flags & S_NOATIME)
1534 if (IS_NOATIME(inode))
1536 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1539 if (mnt->mnt_flags & MNT_NOATIME)
1541 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1544 now = current_fs_time(inode->i_sb);
1546 if (!relatime_need_update(mnt, inode, now))
1549 if (timespec_equal(&inode->i_atime, &now))
1552 if (!sb_start_write_trylock(inode->i_sb))
1555 if (__mnt_want_write(mnt))
1558 * File systems can error out when updating inodes if they need to
1559 * allocate new space to modify an inode (such is the case for
1560 * Btrfs), but since we touch atime while walking down the path we
1561 * really don't care if we failed to update the atime of the file,
1562 * so just ignore the return value.
1563 * We may also fail on filesystems that have the ability to make parts
1564 * of the fs read only, e.g. subvolumes in Btrfs.
1566 update_time(inode, &now, S_ATIME);
1567 __mnt_drop_write(mnt);
1569 sb_end_write(inode->i_sb);
1571 EXPORT_SYMBOL(touch_atime);
1574 * The logic we want is
1576 * if suid or (sgid and xgrp)
1579 int should_remove_suid(struct dentry *dentry)
1581 umode_t mode = dentry->d_inode->i_mode;
1584 /* suid always must be killed */
1585 if (unlikely(mode & S_ISUID))
1586 kill = ATTR_KILL_SUID;
1589 * sgid without any exec bits is just a mandatory locking mark; leave
1590 * it alone. If some exec bits are set, it's a real sgid; kill it.
1592 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1593 kill |= ATTR_KILL_SGID;
1595 if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
1600 EXPORT_SYMBOL(should_remove_suid);
1602 static int __remove_suid(struct dentry *dentry, int kill)
1604 struct iattr newattrs;
1606 newattrs.ia_valid = ATTR_FORCE | kill;
1608 * Note we call this on write, so notify_change will not
1609 * encounter any conflicting delegations:
1611 return notify_change(dentry, &newattrs, NULL);
1614 int file_remove_suid(struct file *file)
1616 struct dentry *dentry = file->f_path.dentry;
1617 struct inode *inode = dentry->d_inode;
1622 /* Fast path for nothing security related */
1623 if (IS_NOSEC(inode))
1626 killsuid = should_remove_suid(dentry);
1627 killpriv = security_inode_need_killpriv(dentry);
1632 error = security_inode_killpriv(dentry);
1633 if (!error && killsuid)
1634 error = __remove_suid(dentry, killsuid);
1635 if (!error && (inode->i_sb->s_flags & MS_NOSEC))
1636 inode->i_flags |= S_NOSEC;
1640 EXPORT_SYMBOL(file_remove_suid);
1643 * file_update_time - update mtime and ctime time
1644 * @file: file accessed
1646 * Update the mtime and ctime members of an inode and mark the inode
1647 * for writeback. Note that this function is meant exclusively for
1648 * usage in the file write path of filesystems, and filesystems may
1649 * choose to explicitly ignore update via this function with the
1650 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1651 * timestamps are handled by the server. This can return an error for
1652 * file systems who need to allocate space in order to update an inode.
1655 int file_update_time(struct file *file)
1657 struct inode *inode = file_inode(file);
1658 struct timespec now;
1662 /* First try to exhaust all avenues to not sync */
1663 if (IS_NOCMTIME(inode))
1666 now = current_fs_time(inode->i_sb);
1667 if (!timespec_equal(&inode->i_mtime, &now))
1670 if (!timespec_equal(&inode->i_ctime, &now))
1673 if (IS_I_VERSION(inode))
1674 sync_it |= S_VERSION;
1679 /* Finally allowed to write? Takes lock. */
1680 if (__mnt_want_write_file(file))
1683 ret = update_time(inode, &now, sync_it);
1684 __mnt_drop_write_file(file);
1688 EXPORT_SYMBOL(file_update_time);
1690 int inode_needs_sync(struct inode *inode)
1694 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1698 EXPORT_SYMBOL(inode_needs_sync);
1701 * If we try to find an inode in the inode hash while it is being
1702 * deleted, we have to wait until the filesystem completes its
1703 * deletion before reporting that it isn't found. This function waits
1704 * until the deletion _might_ have completed. Callers are responsible
1705 * to recheck inode state.
1707 * It doesn't matter if I_NEW is not set initially, a call to
1708 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1711 static void __wait_on_freeing_inode(struct inode *inode)
1713 wait_queue_head_t *wq;
1714 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1715 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1716 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1717 spin_unlock(&inode->i_lock);
1718 spin_unlock(&inode_hash_lock);
1720 finish_wait(wq, &wait.wait);
1721 spin_lock(&inode_hash_lock);
1724 static __initdata unsigned long ihash_entries;
1725 static int __init set_ihash_entries(char *str)
1729 ihash_entries = simple_strtoul(str, &str, 0);
1732 __setup("ihash_entries=", set_ihash_entries);
1735 * Initialize the waitqueues and inode hash table.
1737 void __init inode_init_early(void)
1741 /* If hashes are distributed across NUMA nodes, defer
1742 * hash allocation until vmalloc space is available.
1748 alloc_large_system_hash("Inode-cache",
1749 sizeof(struct hlist_head),
1758 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1759 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1762 void __init inode_init(void)
1766 /* inode slab cache */
1767 inode_cachep = kmem_cache_create("inode_cache",
1768 sizeof(struct inode),
1770 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1774 /* Hash may have been set up in inode_init_early */
1779 alloc_large_system_hash("Inode-cache",
1780 sizeof(struct hlist_head),
1789 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1790 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1793 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1795 inode->i_mode = mode;
1796 if (S_ISCHR(mode)) {
1797 inode->i_fop = &def_chr_fops;
1798 inode->i_rdev = rdev;
1799 } else if (S_ISBLK(mode)) {
1800 inode->i_fop = &def_blk_fops;
1801 inode->i_rdev = rdev;
1802 } else if (S_ISFIFO(mode))
1803 inode->i_fop = &pipefifo_fops;
1804 else if (S_ISSOCK(mode))
1805 ; /* leave it no_open_fops */
1807 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1808 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1811 EXPORT_SYMBOL(init_special_inode);
1814 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1816 * @dir: Directory inode
1817 * @mode: mode of the new inode
1819 void inode_init_owner(struct inode *inode, const struct inode *dir,
1822 inode->i_uid = current_fsuid();
1823 if (dir && dir->i_mode & S_ISGID) {
1824 inode->i_gid = dir->i_gid;
1828 inode->i_gid = current_fsgid();
1829 inode->i_mode = mode;
1831 EXPORT_SYMBOL(inode_init_owner);
1834 * inode_owner_or_capable - check current task permissions to inode
1835 * @inode: inode being checked
1837 * Return true if current either has CAP_FOWNER in a namespace with the
1838 * inode owner uid mapped, or owns the file.
1840 bool inode_owner_or_capable(const struct inode *inode)
1842 struct user_namespace *ns;
1844 if (uid_eq(current_fsuid(), inode->i_uid))
1847 ns = current_user_ns();
1848 if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid))
1852 EXPORT_SYMBOL(inode_owner_or_capable);
1855 * Direct i/o helper functions
1857 static void __inode_dio_wait(struct inode *inode)
1859 wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
1860 DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
1863 prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
1864 if (atomic_read(&inode->i_dio_count))
1866 } while (atomic_read(&inode->i_dio_count));
1867 finish_wait(wq, &q.wait);
1871 * inode_dio_wait - wait for outstanding DIO requests to finish
1872 * @inode: inode to wait for
1874 * Waits for all pending direct I/O requests to finish so that we can
1875 * proceed with a truncate or equivalent operation.
1877 * Must be called under a lock that serializes taking new references
1878 * to i_dio_count, usually by inode->i_mutex.
1880 void inode_dio_wait(struct inode *inode)
1882 if (atomic_read(&inode->i_dio_count))
1883 __inode_dio_wait(inode);
1885 EXPORT_SYMBOL(inode_dio_wait);
1888 * inode_dio_done - signal finish of a direct I/O requests
1889 * @inode: inode the direct I/O happens on
1891 * This is called once we've finished processing a direct I/O request,
1892 * and is used to wake up callers waiting for direct I/O to be quiesced.
1894 void inode_dio_done(struct inode *inode)
1896 if (atomic_dec_and_test(&inode->i_dio_count))
1897 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
1899 EXPORT_SYMBOL(inode_dio_done);
1902 * inode_set_flags - atomically set some inode flags
1904 * Note: the caller should be holding i_mutex, or else be sure that
1905 * they have exclusive access to the inode structure (i.e., while the
1906 * inode is being instantiated). The reason for the cmpxchg() loop
1907 * --- which wouldn't be necessary if all code paths which modify
1908 * i_flags actually followed this rule, is that there is at least one
1909 * code path which doesn't today --- for example,
1910 * __generic_file_aio_write() calls file_remove_suid() without holding
1911 * i_mutex --- so we use cmpxchg() out of an abundance of caution.
1913 * In the long run, i_mutex is overkill, and we should probably look
1914 * at using the i_lock spinlock to protect i_flags, and then make sure
1915 * it is so documented in include/linux/fs.h and that all code follows
1916 * the locking convention!!
1918 void inode_set_flags(struct inode *inode, unsigned int flags,
1921 unsigned int old_flags, new_flags;
1923 WARN_ON_ONCE(flags & ~mask);
1925 old_flags = ACCESS_ONCE(inode->i_flags);
1926 new_flags = (old_flags & ~mask) | flags;
1927 } while (unlikely(cmpxchg(&inode->i_flags, old_flags,
1928 new_flags) != old_flags));
1930 EXPORT_SYMBOL(inode_set_flags);