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->writeback_index = 0;
174 inode->i_private = NULL;
175 inode->i_mapping = mapping;
176 INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
177 #ifdef CONFIG_FS_POSIX_ACL
178 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
181 #ifdef CONFIG_FSNOTIFY
182 inode->i_fsnotify_mask = 0;
184 inode->i_flctx = NULL;
185 this_cpu_inc(nr_inodes);
191 EXPORT_SYMBOL(inode_init_always);
193 static struct inode *alloc_inode(struct super_block *sb)
197 if (sb->s_op->alloc_inode)
198 inode = sb->s_op->alloc_inode(sb);
200 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
205 if (unlikely(inode_init_always(sb, inode))) {
206 if (inode->i_sb->s_op->destroy_inode)
207 inode->i_sb->s_op->destroy_inode(inode);
209 kmem_cache_free(inode_cachep, inode);
216 void free_inode_nonrcu(struct inode *inode)
218 kmem_cache_free(inode_cachep, inode);
220 EXPORT_SYMBOL(free_inode_nonrcu);
222 void __destroy_inode(struct inode *inode)
224 BUG_ON(inode_has_buffers(inode));
225 security_inode_free(inode);
226 fsnotify_inode_delete(inode);
227 locks_free_lock_context(inode->i_flctx);
228 if (!inode->i_nlink) {
229 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
230 atomic_long_dec(&inode->i_sb->s_remove_count);
233 #ifdef CONFIG_FS_POSIX_ACL
234 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
235 posix_acl_release(inode->i_acl);
236 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
237 posix_acl_release(inode->i_default_acl);
239 this_cpu_dec(nr_inodes);
241 EXPORT_SYMBOL(__destroy_inode);
243 static void i_callback(struct rcu_head *head)
245 struct inode *inode = container_of(head, struct inode, i_rcu);
246 kmem_cache_free(inode_cachep, inode);
249 static void destroy_inode(struct inode *inode)
251 BUG_ON(!list_empty(&inode->i_lru));
252 __destroy_inode(inode);
253 if (inode->i_sb->s_op->destroy_inode)
254 inode->i_sb->s_op->destroy_inode(inode);
256 call_rcu(&inode->i_rcu, i_callback);
260 * drop_nlink - directly drop an inode's link count
263 * This is a low-level filesystem helper to replace any
264 * direct filesystem manipulation of i_nlink. In cases
265 * where we are attempting to track writes to the
266 * filesystem, a decrement to zero means an imminent
267 * write when the file is truncated and actually unlinked
270 void drop_nlink(struct inode *inode)
272 WARN_ON(inode->i_nlink == 0);
275 atomic_long_inc(&inode->i_sb->s_remove_count);
277 EXPORT_SYMBOL(drop_nlink);
280 * clear_nlink - directly zero an inode's link count
283 * This is a low-level filesystem helper to replace any
284 * direct filesystem manipulation of i_nlink. See
285 * drop_nlink() for why we care about i_nlink hitting zero.
287 void clear_nlink(struct inode *inode)
289 if (inode->i_nlink) {
290 inode->__i_nlink = 0;
291 atomic_long_inc(&inode->i_sb->s_remove_count);
294 EXPORT_SYMBOL(clear_nlink);
297 * set_nlink - directly set an inode's link count
299 * @nlink: new nlink (should be non-zero)
301 * This is a low-level filesystem helper to replace any
302 * direct filesystem manipulation of i_nlink.
304 void set_nlink(struct inode *inode, unsigned int nlink)
309 /* Yes, some filesystems do change nlink from zero to one */
310 if (inode->i_nlink == 0)
311 atomic_long_dec(&inode->i_sb->s_remove_count);
313 inode->__i_nlink = nlink;
316 EXPORT_SYMBOL(set_nlink);
319 * inc_nlink - directly increment an inode's link count
322 * This is a low-level filesystem helper to replace any
323 * direct filesystem manipulation of i_nlink. Currently,
324 * it is only here for parity with dec_nlink().
326 void inc_nlink(struct inode *inode)
328 if (unlikely(inode->i_nlink == 0)) {
329 WARN_ON(!(inode->i_state & I_LINKABLE));
330 atomic_long_dec(&inode->i_sb->s_remove_count);
335 EXPORT_SYMBOL(inc_nlink);
337 void address_space_init_once(struct address_space *mapping)
339 memset(mapping, 0, sizeof(*mapping));
340 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
341 spin_lock_init(&mapping->tree_lock);
342 init_rwsem(&mapping->i_mmap_rwsem);
343 INIT_LIST_HEAD(&mapping->private_list);
344 spin_lock_init(&mapping->private_lock);
345 mapping->i_mmap = RB_ROOT;
347 EXPORT_SYMBOL(address_space_init_once);
350 * These are initializations that only need to be done
351 * once, because the fields are idempotent across use
352 * of the inode, so let the slab aware of that.
354 void inode_init_once(struct inode *inode)
356 memset(inode, 0, sizeof(*inode));
357 INIT_HLIST_NODE(&inode->i_hash);
358 INIT_LIST_HEAD(&inode->i_devices);
359 INIT_LIST_HEAD(&inode->i_wb_list);
360 INIT_LIST_HEAD(&inode->i_lru);
361 address_space_init_once(&inode->i_data);
362 i_size_ordered_init(inode);
363 #ifdef CONFIG_FSNOTIFY
364 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
367 EXPORT_SYMBOL(inode_init_once);
369 static void init_once(void *foo)
371 struct inode *inode = (struct inode *) foo;
373 inode_init_once(inode);
377 * inode->i_lock must be held
379 void __iget(struct inode *inode)
381 atomic_inc(&inode->i_count);
385 * get additional reference to inode; caller must already hold one.
387 void ihold(struct inode *inode)
389 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
391 EXPORT_SYMBOL(ihold);
393 static void inode_lru_list_add(struct inode *inode)
395 if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
396 this_cpu_inc(nr_unused);
400 * Add inode to LRU if needed (inode is unused and clean).
402 * Needs inode->i_lock held.
404 void inode_add_lru(struct inode *inode)
406 if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) &&
407 !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE)
408 inode_lru_list_add(inode);
412 static void inode_lru_list_del(struct inode *inode)
415 if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
416 this_cpu_dec(nr_unused);
420 * inode_sb_list_add - add inode to the superblock list of inodes
421 * @inode: inode to add
423 void inode_sb_list_add(struct inode *inode)
425 spin_lock(&inode_sb_list_lock);
426 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
427 spin_unlock(&inode_sb_list_lock);
429 EXPORT_SYMBOL_GPL(inode_sb_list_add);
431 static inline void inode_sb_list_del(struct inode *inode)
433 if (!list_empty(&inode->i_sb_list)) {
434 spin_lock(&inode_sb_list_lock);
435 list_del_init(&inode->i_sb_list);
436 spin_unlock(&inode_sb_list_lock);
440 static unsigned long hash(struct super_block *sb, unsigned long hashval)
444 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
446 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
447 return tmp & i_hash_mask;
451 * __insert_inode_hash - hash an inode
452 * @inode: unhashed inode
453 * @hashval: unsigned long value used to locate this object in the
456 * Add an inode to the inode hash for this superblock.
458 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
460 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
462 spin_lock(&inode_hash_lock);
463 spin_lock(&inode->i_lock);
464 hlist_add_head(&inode->i_hash, b);
465 spin_unlock(&inode->i_lock);
466 spin_unlock(&inode_hash_lock);
468 EXPORT_SYMBOL(__insert_inode_hash);
471 * __remove_inode_hash - remove an inode from the hash
472 * @inode: inode to unhash
474 * Remove an inode from the superblock.
476 void __remove_inode_hash(struct inode *inode)
478 spin_lock(&inode_hash_lock);
479 spin_lock(&inode->i_lock);
480 hlist_del_init(&inode->i_hash);
481 spin_unlock(&inode->i_lock);
482 spin_unlock(&inode_hash_lock);
484 EXPORT_SYMBOL(__remove_inode_hash);
486 void clear_inode(struct inode *inode)
490 * We have to cycle tree_lock here because reclaim can be still in the
491 * process of removing the last page (in __delete_from_page_cache())
492 * and we must not free mapping under it.
494 spin_lock_irq(&inode->i_data.tree_lock);
495 BUG_ON(inode->i_data.nrpages);
496 BUG_ON(inode->i_data.nrshadows);
497 spin_unlock_irq(&inode->i_data.tree_lock);
498 BUG_ON(!list_empty(&inode->i_data.private_list));
499 BUG_ON(!(inode->i_state & I_FREEING));
500 BUG_ON(inode->i_state & I_CLEAR);
501 /* don't need i_lock here, no concurrent mods to i_state */
502 inode->i_state = I_FREEING | I_CLEAR;
504 EXPORT_SYMBOL(clear_inode);
507 * Free the inode passed in, removing it from the lists it is still connected
508 * to. We remove any pages still attached to the inode and wait for any IO that
509 * is still in progress before finally destroying the inode.
511 * An inode must already be marked I_FREEING so that we avoid the inode being
512 * moved back onto lists if we race with other code that manipulates the lists
513 * (e.g. writeback_single_inode). The caller is responsible for setting this.
515 * An inode must already be removed from the LRU list before being evicted from
516 * the cache. This should occur atomically with setting the I_FREEING state
517 * flag, so no inodes here should ever be on the LRU when being evicted.
519 static void evict(struct inode *inode)
521 const struct super_operations *op = inode->i_sb->s_op;
523 BUG_ON(!(inode->i_state & I_FREEING));
524 BUG_ON(!list_empty(&inode->i_lru));
526 if (!list_empty(&inode->i_wb_list))
527 inode_wb_list_del(inode);
529 inode_sb_list_del(inode);
532 * Wait for flusher thread to be done with the inode so that filesystem
533 * does not start destroying it while writeback is still running. Since
534 * the inode has I_FREEING set, flusher thread won't start new work on
535 * the inode. We just have to wait for running writeback to finish.
537 inode_wait_for_writeback(inode);
539 if (op->evict_inode) {
540 op->evict_inode(inode);
542 truncate_inode_pages_final(&inode->i_data);
545 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
547 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
550 remove_inode_hash(inode);
552 spin_lock(&inode->i_lock);
553 wake_up_bit(&inode->i_state, __I_NEW);
554 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
555 spin_unlock(&inode->i_lock);
557 destroy_inode(inode);
561 * dispose_list - dispose of the contents of a local list
562 * @head: the head of the list to free
564 * Dispose-list gets a local list with local inodes in it, so it doesn't
565 * need to worry about list corruption and SMP locks.
567 static void dispose_list(struct list_head *head)
569 while (!list_empty(head)) {
572 inode = list_first_entry(head, struct inode, i_lru);
573 list_del_init(&inode->i_lru);
580 * evict_inodes - evict all evictable inodes for a superblock
581 * @sb: superblock to operate on
583 * Make sure that no inodes with zero refcount are retained. This is
584 * called by superblock shutdown after having MS_ACTIVE flag removed,
585 * so any inode reaching zero refcount during or after that call will
586 * be immediately evicted.
588 void evict_inodes(struct super_block *sb)
590 struct inode *inode, *next;
593 spin_lock(&inode_sb_list_lock);
594 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
595 if (atomic_read(&inode->i_count))
598 spin_lock(&inode->i_lock);
599 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
600 spin_unlock(&inode->i_lock);
604 inode->i_state |= I_FREEING;
605 inode_lru_list_del(inode);
606 spin_unlock(&inode->i_lock);
607 list_add(&inode->i_lru, &dispose);
609 spin_unlock(&inode_sb_list_lock);
611 dispose_list(&dispose);
615 * invalidate_inodes - attempt to free all inodes on a superblock
616 * @sb: superblock to operate on
617 * @kill_dirty: flag to guide handling of dirty inodes
619 * Attempts to free all inodes for a given superblock. If there were any
620 * busy inodes return a non-zero value, else zero.
621 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
624 int invalidate_inodes(struct super_block *sb, bool kill_dirty)
627 struct inode *inode, *next;
630 spin_lock(&inode_sb_list_lock);
631 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
632 spin_lock(&inode->i_lock);
633 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
634 spin_unlock(&inode->i_lock);
637 if (inode->i_state & I_DIRTY && !kill_dirty) {
638 spin_unlock(&inode->i_lock);
642 if (atomic_read(&inode->i_count)) {
643 spin_unlock(&inode->i_lock);
648 inode->i_state |= I_FREEING;
649 inode_lru_list_del(inode);
650 spin_unlock(&inode->i_lock);
651 list_add(&inode->i_lru, &dispose);
653 spin_unlock(&inode_sb_list_lock);
655 dispose_list(&dispose);
661 * Isolate the inode from the LRU in preparation for freeing it.
663 * Any inodes which are pinned purely because of attached pagecache have their
664 * pagecache removed. If the inode has metadata buffers attached to
665 * mapping->private_list then try to remove them.
667 * If the inode has the I_REFERENCED flag set, then it means that it has been
668 * used recently - the flag is set in iput_final(). When we encounter such an
669 * inode, clear the flag and move it to the back of the LRU so it gets another
670 * pass through the LRU before it gets reclaimed. This is necessary because of
671 * the fact we are doing lazy LRU updates to minimise lock contention so the
672 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
673 * with this flag set because they are the inodes that are out of order.
675 static enum lru_status
676 inode_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg)
678 struct list_head *freeable = arg;
679 struct inode *inode = container_of(item, struct inode, i_lru);
682 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
683 * If we fail to get the lock, just skip it.
685 if (!spin_trylock(&inode->i_lock))
689 * Referenced or dirty inodes are still in use. Give them another pass
690 * through the LRU as we canot reclaim them now.
692 if (atomic_read(&inode->i_count) ||
693 (inode->i_state & ~I_REFERENCED)) {
694 list_del_init(&inode->i_lru);
695 spin_unlock(&inode->i_lock);
696 this_cpu_dec(nr_unused);
700 /* recently referenced inodes get one more pass */
701 if (inode->i_state & I_REFERENCED) {
702 inode->i_state &= ~I_REFERENCED;
703 spin_unlock(&inode->i_lock);
707 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
709 spin_unlock(&inode->i_lock);
710 spin_unlock(lru_lock);
711 if (remove_inode_buffers(inode)) {
713 reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
714 if (current_is_kswapd())
715 __count_vm_events(KSWAPD_INODESTEAL, reap);
717 __count_vm_events(PGINODESTEAL, reap);
718 if (current->reclaim_state)
719 current->reclaim_state->reclaimed_slab += reap;
726 WARN_ON(inode->i_state & I_NEW);
727 inode->i_state |= I_FREEING;
728 list_move(&inode->i_lru, freeable);
729 spin_unlock(&inode->i_lock);
731 this_cpu_dec(nr_unused);
736 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
737 * This is called from the superblock shrinker function with a number of inodes
738 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
739 * then are freed outside inode_lock by dispose_list().
741 long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
747 freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate,
748 &freeable, &nr_to_scan);
749 dispose_list(&freeable);
753 static void __wait_on_freeing_inode(struct inode *inode);
755 * Called with the inode lock held.
757 static struct inode *find_inode(struct super_block *sb,
758 struct hlist_head *head,
759 int (*test)(struct inode *, void *),
762 struct inode *inode = NULL;
765 hlist_for_each_entry(inode, head, i_hash) {
766 if (inode->i_sb != sb)
768 if (!test(inode, data))
770 spin_lock(&inode->i_lock);
771 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
772 __wait_on_freeing_inode(inode);
776 spin_unlock(&inode->i_lock);
783 * find_inode_fast is the fast path version of find_inode, see the comment at
784 * iget_locked for details.
786 static struct inode *find_inode_fast(struct super_block *sb,
787 struct hlist_head *head, unsigned long ino)
789 struct inode *inode = NULL;
792 hlist_for_each_entry(inode, head, i_hash) {
793 if (inode->i_ino != ino)
795 if (inode->i_sb != sb)
797 spin_lock(&inode->i_lock);
798 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
799 __wait_on_freeing_inode(inode);
803 spin_unlock(&inode->i_lock);
810 * Each cpu owns a range of LAST_INO_BATCH numbers.
811 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
812 * to renew the exhausted range.
814 * This does not significantly increase overflow rate because every CPU can
815 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
816 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
817 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
818 * overflow rate by 2x, which does not seem too significant.
820 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
821 * error if st_ino won't fit in target struct field. Use 32bit counter
822 * here to attempt to avoid that.
824 #define LAST_INO_BATCH 1024
825 static DEFINE_PER_CPU(unsigned int, last_ino);
827 unsigned int get_next_ino(void)
829 unsigned int *p = &get_cpu_var(last_ino);
830 unsigned int res = *p;
833 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
834 static atomic_t shared_last_ino;
835 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
837 res = next - LAST_INO_BATCH;
842 put_cpu_var(last_ino);
845 EXPORT_SYMBOL(get_next_ino);
848 * new_inode_pseudo - obtain an inode
851 * Allocates a new inode for given superblock.
852 * Inode wont be chained in superblock s_inodes list
854 * - fs can't be unmount
855 * - quotas, fsnotify, writeback can't work
857 struct inode *new_inode_pseudo(struct super_block *sb)
859 struct inode *inode = alloc_inode(sb);
862 spin_lock(&inode->i_lock);
864 spin_unlock(&inode->i_lock);
865 INIT_LIST_HEAD(&inode->i_sb_list);
871 * new_inode - obtain an inode
874 * Allocates a new inode for given superblock. The default gfp_mask
875 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
876 * If HIGHMEM pages are unsuitable or it is known that pages allocated
877 * for the page cache are not reclaimable or migratable,
878 * mapping_set_gfp_mask() must be called with suitable flags on the
879 * newly created inode's mapping
882 struct inode *new_inode(struct super_block *sb)
886 spin_lock_prefetch(&inode_sb_list_lock);
888 inode = new_inode_pseudo(sb);
890 inode_sb_list_add(inode);
893 EXPORT_SYMBOL(new_inode);
895 #ifdef CONFIG_DEBUG_LOCK_ALLOC
896 void lockdep_annotate_inode_mutex_key(struct inode *inode)
898 if (S_ISDIR(inode->i_mode)) {
899 struct file_system_type *type = inode->i_sb->s_type;
901 /* Set new key only if filesystem hasn't already changed it */
902 if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) {
904 * ensure nobody is actually holding i_mutex
906 mutex_destroy(&inode->i_mutex);
907 mutex_init(&inode->i_mutex);
908 lockdep_set_class(&inode->i_mutex,
909 &type->i_mutex_dir_key);
913 EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
917 * unlock_new_inode - clear the I_NEW state and wake up any waiters
918 * @inode: new inode to unlock
920 * Called when the inode is fully initialised to clear the new state of the
921 * inode and wake up anyone waiting for the inode to finish initialisation.
923 void unlock_new_inode(struct inode *inode)
925 lockdep_annotate_inode_mutex_key(inode);
926 spin_lock(&inode->i_lock);
927 WARN_ON(!(inode->i_state & I_NEW));
928 inode->i_state &= ~I_NEW;
930 wake_up_bit(&inode->i_state, __I_NEW);
931 spin_unlock(&inode->i_lock);
933 EXPORT_SYMBOL(unlock_new_inode);
936 * lock_two_nondirectories - take two i_mutexes on non-directory objects
938 * Lock any non-NULL argument that is not a directory.
939 * Zero, one or two objects may be locked by this function.
941 * @inode1: first inode to lock
942 * @inode2: second inode to lock
944 void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
947 swap(inode1, inode2);
949 if (inode1 && !S_ISDIR(inode1->i_mode))
950 mutex_lock(&inode1->i_mutex);
951 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
952 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
954 EXPORT_SYMBOL(lock_two_nondirectories);
957 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
958 * @inode1: first inode to unlock
959 * @inode2: second inode to unlock
961 void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
963 if (inode1 && !S_ISDIR(inode1->i_mode))
964 mutex_unlock(&inode1->i_mutex);
965 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
966 mutex_unlock(&inode2->i_mutex);
968 EXPORT_SYMBOL(unlock_two_nondirectories);
971 * iget5_locked - obtain an inode from a mounted file system
972 * @sb: super block of file system
973 * @hashval: hash value (usually inode number) to get
974 * @test: callback used for comparisons between inodes
975 * @set: callback used to initialize a new struct inode
976 * @data: opaque data pointer to pass to @test and @set
978 * Search for the inode specified by @hashval and @data in the inode cache,
979 * and if present it is return it with an increased reference count. This is
980 * a generalized version of iget_locked() for file systems where the inode
981 * number is not sufficient for unique identification of an inode.
983 * If the inode is not in cache, allocate a new inode and return it locked,
984 * hashed, and with the I_NEW flag set. The file system gets to fill it in
985 * before unlocking it via unlock_new_inode().
987 * Note both @test and @set are called with the inode_hash_lock held, so can't
990 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
991 int (*test)(struct inode *, void *),
992 int (*set)(struct inode *, void *), void *data)
994 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
997 spin_lock(&inode_hash_lock);
998 inode = find_inode(sb, head, test, data);
999 spin_unlock(&inode_hash_lock);
1002 wait_on_inode(inode);
1006 inode = alloc_inode(sb);
1010 spin_lock(&inode_hash_lock);
1011 /* We released the lock, so.. */
1012 old = find_inode(sb, head, test, data);
1014 if (set(inode, data))
1017 spin_lock(&inode->i_lock);
1018 inode->i_state = I_NEW;
1019 hlist_add_head(&inode->i_hash, head);
1020 spin_unlock(&inode->i_lock);
1021 inode_sb_list_add(inode);
1022 spin_unlock(&inode_hash_lock);
1024 /* Return the locked inode with I_NEW set, the
1025 * caller is responsible for filling in the contents
1031 * Uhhuh, somebody else created the same inode under
1032 * us. Use the old inode instead of the one we just
1035 spin_unlock(&inode_hash_lock);
1036 destroy_inode(inode);
1038 wait_on_inode(inode);
1043 spin_unlock(&inode_hash_lock);
1044 destroy_inode(inode);
1047 EXPORT_SYMBOL(iget5_locked);
1050 * iget_locked - obtain an inode from a mounted file system
1051 * @sb: super block of file system
1052 * @ino: inode number to get
1054 * Search for the inode specified by @ino in the inode cache and if present
1055 * return it with an increased reference count. This is for file systems
1056 * where the inode number is sufficient for unique identification of an inode.
1058 * If the inode is not in cache, allocate a new inode and return it locked,
1059 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1060 * before unlocking it via unlock_new_inode().
1062 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1064 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1065 struct inode *inode;
1067 spin_lock(&inode_hash_lock);
1068 inode = find_inode_fast(sb, head, ino);
1069 spin_unlock(&inode_hash_lock);
1071 wait_on_inode(inode);
1075 inode = alloc_inode(sb);
1079 spin_lock(&inode_hash_lock);
1080 /* We released the lock, so.. */
1081 old = find_inode_fast(sb, head, ino);
1084 spin_lock(&inode->i_lock);
1085 inode->i_state = I_NEW;
1086 hlist_add_head(&inode->i_hash, head);
1087 spin_unlock(&inode->i_lock);
1088 inode_sb_list_add(inode);
1089 spin_unlock(&inode_hash_lock);
1091 /* Return the locked inode with I_NEW set, the
1092 * caller is responsible for filling in the contents
1098 * Uhhuh, somebody else created the same inode under
1099 * us. Use the old inode instead of the one we just
1102 spin_unlock(&inode_hash_lock);
1103 destroy_inode(inode);
1105 wait_on_inode(inode);
1109 EXPORT_SYMBOL(iget_locked);
1112 * search the inode cache for a matching inode number.
1113 * If we find one, then the inode number we are trying to
1114 * allocate is not unique and so we should not use it.
1116 * Returns 1 if the inode number is unique, 0 if it is not.
1118 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1120 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1121 struct inode *inode;
1123 spin_lock(&inode_hash_lock);
1124 hlist_for_each_entry(inode, b, i_hash) {
1125 if (inode->i_ino == ino && inode->i_sb == sb) {
1126 spin_unlock(&inode_hash_lock);
1130 spin_unlock(&inode_hash_lock);
1136 * iunique - get a unique inode number
1138 * @max_reserved: highest reserved inode number
1140 * Obtain an inode number that is unique on the system for a given
1141 * superblock. This is used by file systems that have no natural
1142 * permanent inode numbering system. An inode number is returned that
1143 * is higher than the reserved limit but unique.
1146 * With a large number of inodes live on the file system this function
1147 * currently becomes quite slow.
1149 ino_t iunique(struct super_block *sb, ino_t max_reserved)
1152 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1153 * error if st_ino won't fit in target struct field. Use 32bit counter
1154 * here to attempt to avoid that.
1156 static DEFINE_SPINLOCK(iunique_lock);
1157 static unsigned int counter;
1160 spin_lock(&iunique_lock);
1162 if (counter <= max_reserved)
1163 counter = max_reserved + 1;
1165 } while (!test_inode_iunique(sb, res));
1166 spin_unlock(&iunique_lock);
1170 EXPORT_SYMBOL(iunique);
1172 struct inode *igrab(struct inode *inode)
1174 spin_lock(&inode->i_lock);
1175 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1177 spin_unlock(&inode->i_lock);
1179 spin_unlock(&inode->i_lock);
1181 * Handle the case where s_op->clear_inode is not been
1182 * called yet, and somebody is calling igrab
1183 * while the inode is getting freed.
1189 EXPORT_SYMBOL(igrab);
1192 * ilookup5_nowait - search for an inode in the inode cache
1193 * @sb: super block of file system to search
1194 * @hashval: hash value (usually inode number) to search for
1195 * @test: callback used for comparisons between inodes
1196 * @data: opaque data pointer to pass to @test
1198 * Search for the inode specified by @hashval and @data in the inode cache.
1199 * If the inode is in the cache, the inode is returned with an incremented
1202 * Note: I_NEW is not waited upon so you have to be very careful what you do
1203 * with the returned inode. You probably should be using ilookup5() instead.
1205 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1207 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1208 int (*test)(struct inode *, void *), void *data)
1210 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1211 struct inode *inode;
1213 spin_lock(&inode_hash_lock);
1214 inode = find_inode(sb, head, test, data);
1215 spin_unlock(&inode_hash_lock);
1219 EXPORT_SYMBOL(ilookup5_nowait);
1222 * ilookup5 - search for an inode in the inode cache
1223 * @sb: super block of file system to search
1224 * @hashval: hash value (usually inode number) to search for
1225 * @test: callback used for comparisons between inodes
1226 * @data: opaque data pointer to pass to @test
1228 * Search for the inode specified by @hashval and @data in the inode cache,
1229 * and if the inode is in the cache, return the inode with an incremented
1230 * reference count. Waits on I_NEW before returning the inode.
1231 * returned with an incremented reference count.
1233 * This is a generalized version of ilookup() for file systems where the
1234 * inode number is not sufficient for unique identification of an inode.
1236 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1238 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1239 int (*test)(struct inode *, void *), void *data)
1241 struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
1244 wait_on_inode(inode);
1247 EXPORT_SYMBOL(ilookup5);
1250 * ilookup - search for an inode in the inode cache
1251 * @sb: super block of file system to search
1252 * @ino: inode number to search for
1254 * Search for the inode @ino in the inode cache, and if the inode is in the
1255 * cache, the inode is returned with an incremented reference count.
1257 struct inode *ilookup(struct super_block *sb, unsigned long ino)
1259 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1260 struct inode *inode;
1262 spin_lock(&inode_hash_lock);
1263 inode = find_inode_fast(sb, head, ino);
1264 spin_unlock(&inode_hash_lock);
1267 wait_on_inode(inode);
1270 EXPORT_SYMBOL(ilookup);
1272 int insert_inode_locked(struct inode *inode)
1274 struct super_block *sb = inode->i_sb;
1275 ino_t ino = inode->i_ino;
1276 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1279 struct inode *old = NULL;
1280 spin_lock(&inode_hash_lock);
1281 hlist_for_each_entry(old, head, i_hash) {
1282 if (old->i_ino != ino)
1284 if (old->i_sb != sb)
1286 spin_lock(&old->i_lock);
1287 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1288 spin_unlock(&old->i_lock);
1294 spin_lock(&inode->i_lock);
1295 inode->i_state |= I_NEW;
1296 hlist_add_head(&inode->i_hash, head);
1297 spin_unlock(&inode->i_lock);
1298 spin_unlock(&inode_hash_lock);
1302 spin_unlock(&old->i_lock);
1303 spin_unlock(&inode_hash_lock);
1305 if (unlikely(!inode_unhashed(old))) {
1312 EXPORT_SYMBOL(insert_inode_locked);
1314 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1315 int (*test)(struct inode *, void *), void *data)
1317 struct super_block *sb = inode->i_sb;
1318 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1321 struct inode *old = NULL;
1323 spin_lock(&inode_hash_lock);
1324 hlist_for_each_entry(old, head, i_hash) {
1325 if (old->i_sb != sb)
1327 if (!test(old, data))
1329 spin_lock(&old->i_lock);
1330 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1331 spin_unlock(&old->i_lock);
1337 spin_lock(&inode->i_lock);
1338 inode->i_state |= I_NEW;
1339 hlist_add_head(&inode->i_hash, head);
1340 spin_unlock(&inode->i_lock);
1341 spin_unlock(&inode_hash_lock);
1345 spin_unlock(&old->i_lock);
1346 spin_unlock(&inode_hash_lock);
1348 if (unlikely(!inode_unhashed(old))) {
1355 EXPORT_SYMBOL(insert_inode_locked4);
1358 int generic_delete_inode(struct inode *inode)
1362 EXPORT_SYMBOL(generic_delete_inode);
1365 * Called when we're dropping the last reference
1368 * Call the FS "drop_inode()" function, defaulting to
1369 * the legacy UNIX filesystem behaviour. If it tells
1370 * us to evict inode, do so. Otherwise, retain inode
1371 * in cache if fs is alive, sync and evict if fs is
1374 static void iput_final(struct inode *inode)
1376 struct super_block *sb = inode->i_sb;
1377 const struct super_operations *op = inode->i_sb->s_op;
1380 WARN_ON(inode->i_state & I_NEW);
1383 drop = op->drop_inode(inode);
1385 drop = generic_drop_inode(inode);
1387 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1388 inode->i_state |= I_REFERENCED;
1389 inode_add_lru(inode);
1390 spin_unlock(&inode->i_lock);
1395 inode->i_state |= I_WILL_FREE;
1396 spin_unlock(&inode->i_lock);
1397 write_inode_now(inode, 1);
1398 spin_lock(&inode->i_lock);
1399 WARN_ON(inode->i_state & I_NEW);
1400 inode->i_state &= ~I_WILL_FREE;
1403 inode->i_state |= I_FREEING;
1404 if (!list_empty(&inode->i_lru))
1405 inode_lru_list_del(inode);
1406 spin_unlock(&inode->i_lock);
1412 * iput - put an inode
1413 * @inode: inode to put
1415 * Puts an inode, dropping its usage count. If the inode use count hits
1416 * zero, the inode is then freed and may also be destroyed.
1418 * Consequently, iput() can sleep.
1420 void iput(struct inode *inode)
1423 BUG_ON(inode->i_state & I_CLEAR);
1425 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
1429 EXPORT_SYMBOL(iput);
1432 * bmap - find a block number in a file
1433 * @inode: inode of file
1434 * @block: block to find
1436 * Returns the block number on the device holding the inode that
1437 * is the disk block number for the block of the file requested.
1438 * That is, asked for block 4 of inode 1 the function will return the
1439 * disk block relative to the disk start that holds that block of the
1442 sector_t bmap(struct inode *inode, sector_t block)
1445 if (inode->i_mapping->a_ops->bmap)
1446 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1449 EXPORT_SYMBOL(bmap);
1452 * With relative atime, only update atime if the previous atime is
1453 * earlier than either the ctime or mtime or if at least a day has
1454 * passed since the last atime update.
1456 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1457 struct timespec now)
1460 if (!(mnt->mnt_flags & MNT_RELATIME))
1463 * Is mtime younger than atime? If yes, update atime:
1465 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1468 * Is ctime younger than atime? If yes, update atime:
1470 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1474 * Is the previous atime value older than a day? If yes,
1477 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1480 * Good, we can skip the atime update:
1486 * This does the actual work of updating an inodes time or version. Must have
1487 * had called mnt_want_write() before calling this.
1489 static int update_time(struct inode *inode, struct timespec *time, int flags)
1491 if (inode->i_op->update_time)
1492 return inode->i_op->update_time(inode, time, flags);
1494 if (flags & S_ATIME)
1495 inode->i_atime = *time;
1496 if (flags & S_VERSION)
1497 inode_inc_iversion(inode);
1498 if (flags & S_CTIME)
1499 inode->i_ctime = *time;
1500 if (flags & S_MTIME)
1501 inode->i_mtime = *time;
1502 mark_inode_dirty_sync(inode);
1507 * touch_atime - update the access time
1508 * @path: the &struct path to update
1510 * Update the accessed time on an inode and mark it for writeback.
1511 * This function automatically handles read only file systems and media,
1512 * as well as the "noatime" flag and inode specific "noatime" markers.
1514 void touch_atime(const struct path *path)
1516 struct vfsmount *mnt = path->mnt;
1517 struct inode *inode = path->dentry->d_inode;
1518 struct timespec now;
1520 if (inode->i_flags & S_NOATIME)
1522 if (IS_NOATIME(inode))
1524 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1527 if (mnt->mnt_flags & MNT_NOATIME)
1529 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1532 now = current_fs_time(inode->i_sb);
1534 if (!relatime_need_update(mnt, inode, now))
1537 if (timespec_equal(&inode->i_atime, &now))
1540 if (!sb_start_write_trylock(inode->i_sb))
1543 if (__mnt_want_write(mnt))
1546 * File systems can error out when updating inodes if they need to
1547 * allocate new space to modify an inode (such is the case for
1548 * Btrfs), but since we touch atime while walking down the path we
1549 * really don't care if we failed to update the atime of the file,
1550 * so just ignore the return value.
1551 * We may also fail on filesystems that have the ability to make parts
1552 * of the fs read only, e.g. subvolumes in Btrfs.
1554 update_time(inode, &now, S_ATIME);
1555 __mnt_drop_write(mnt);
1557 sb_end_write(inode->i_sb);
1559 EXPORT_SYMBOL(touch_atime);
1562 * The logic we want is
1564 * if suid or (sgid and xgrp)
1567 int should_remove_suid(struct dentry *dentry)
1569 umode_t mode = dentry->d_inode->i_mode;
1572 /* suid always must be killed */
1573 if (unlikely(mode & S_ISUID))
1574 kill = ATTR_KILL_SUID;
1577 * sgid without any exec bits is just a mandatory locking mark; leave
1578 * it alone. If some exec bits are set, it's a real sgid; kill it.
1580 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1581 kill |= ATTR_KILL_SGID;
1583 if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
1588 EXPORT_SYMBOL(should_remove_suid);
1590 static int __remove_suid(struct dentry *dentry, int kill)
1592 struct iattr newattrs;
1594 newattrs.ia_valid = ATTR_FORCE | kill;
1596 * Note we call this on write, so notify_change will not
1597 * encounter any conflicting delegations:
1599 return notify_change(dentry, &newattrs, NULL);
1602 int file_remove_suid(struct file *file)
1604 struct dentry *dentry = file->f_path.dentry;
1605 struct inode *inode = dentry->d_inode;
1610 /* Fast path for nothing security related */
1611 if (IS_NOSEC(inode))
1614 killsuid = should_remove_suid(dentry);
1615 killpriv = security_inode_need_killpriv(dentry);
1620 error = security_inode_killpriv(dentry);
1621 if (!error && killsuid)
1622 error = __remove_suid(dentry, killsuid);
1623 if (!error && (inode->i_sb->s_flags & MS_NOSEC))
1624 inode->i_flags |= S_NOSEC;
1628 EXPORT_SYMBOL(file_remove_suid);
1631 * file_update_time - update mtime and ctime time
1632 * @file: file accessed
1634 * Update the mtime and ctime members of an inode and mark the inode
1635 * for writeback. Note that this function is meant exclusively for
1636 * usage in the file write path of filesystems, and filesystems may
1637 * choose to explicitly ignore update via this function with the
1638 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1639 * timestamps are handled by the server. This can return an error for
1640 * file systems who need to allocate space in order to update an inode.
1643 int file_update_time(struct file *file)
1645 struct inode *inode = file_inode(file);
1646 struct timespec now;
1650 /* First try to exhaust all avenues to not sync */
1651 if (IS_NOCMTIME(inode))
1654 now = current_fs_time(inode->i_sb);
1655 if (!timespec_equal(&inode->i_mtime, &now))
1658 if (!timespec_equal(&inode->i_ctime, &now))
1661 if (IS_I_VERSION(inode))
1662 sync_it |= S_VERSION;
1667 /* Finally allowed to write? Takes lock. */
1668 if (__mnt_want_write_file(file))
1671 ret = update_time(inode, &now, sync_it);
1672 __mnt_drop_write_file(file);
1676 EXPORT_SYMBOL(file_update_time);
1678 int inode_needs_sync(struct inode *inode)
1682 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1686 EXPORT_SYMBOL(inode_needs_sync);
1689 * If we try to find an inode in the inode hash while it is being
1690 * deleted, we have to wait until the filesystem completes its
1691 * deletion before reporting that it isn't found. This function waits
1692 * until the deletion _might_ have completed. Callers are responsible
1693 * to recheck inode state.
1695 * It doesn't matter if I_NEW is not set initially, a call to
1696 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1699 static void __wait_on_freeing_inode(struct inode *inode)
1701 wait_queue_head_t *wq;
1702 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1703 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1704 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1705 spin_unlock(&inode->i_lock);
1706 spin_unlock(&inode_hash_lock);
1708 finish_wait(wq, &wait.wait);
1709 spin_lock(&inode_hash_lock);
1712 static __initdata unsigned long ihash_entries;
1713 static int __init set_ihash_entries(char *str)
1717 ihash_entries = simple_strtoul(str, &str, 0);
1720 __setup("ihash_entries=", set_ihash_entries);
1723 * Initialize the waitqueues and inode hash table.
1725 void __init inode_init_early(void)
1729 /* If hashes are distributed across NUMA nodes, defer
1730 * hash allocation until vmalloc space is available.
1736 alloc_large_system_hash("Inode-cache",
1737 sizeof(struct hlist_head),
1746 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1747 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1750 void __init inode_init(void)
1754 /* inode slab cache */
1755 inode_cachep = kmem_cache_create("inode_cache",
1756 sizeof(struct inode),
1758 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1762 /* Hash may have been set up in inode_init_early */
1767 alloc_large_system_hash("Inode-cache",
1768 sizeof(struct hlist_head),
1777 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1778 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1781 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1783 inode->i_mode = mode;
1784 if (S_ISCHR(mode)) {
1785 inode->i_fop = &def_chr_fops;
1786 inode->i_rdev = rdev;
1787 } else if (S_ISBLK(mode)) {
1788 inode->i_fop = &def_blk_fops;
1789 inode->i_rdev = rdev;
1790 } else if (S_ISFIFO(mode))
1791 inode->i_fop = &pipefifo_fops;
1792 else if (S_ISSOCK(mode))
1793 ; /* leave it no_open_fops */
1795 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1796 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1799 EXPORT_SYMBOL(init_special_inode);
1802 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1804 * @dir: Directory inode
1805 * @mode: mode of the new inode
1807 void inode_init_owner(struct inode *inode, const struct inode *dir,
1810 inode->i_uid = current_fsuid();
1811 if (dir && dir->i_mode & S_ISGID) {
1812 inode->i_gid = dir->i_gid;
1816 inode->i_gid = current_fsgid();
1817 inode->i_mode = mode;
1819 EXPORT_SYMBOL(inode_init_owner);
1822 * inode_owner_or_capable - check current task permissions to inode
1823 * @inode: inode being checked
1825 * Return true if current either has CAP_FOWNER in a namespace with the
1826 * inode owner uid mapped, or owns the file.
1828 bool inode_owner_or_capable(const struct inode *inode)
1830 struct user_namespace *ns;
1832 if (uid_eq(current_fsuid(), inode->i_uid))
1835 ns = current_user_ns();
1836 if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid))
1840 EXPORT_SYMBOL(inode_owner_or_capable);
1843 * Direct i/o helper functions
1845 static void __inode_dio_wait(struct inode *inode)
1847 wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
1848 DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
1851 prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
1852 if (atomic_read(&inode->i_dio_count))
1854 } while (atomic_read(&inode->i_dio_count));
1855 finish_wait(wq, &q.wait);
1859 * inode_dio_wait - wait for outstanding DIO requests to finish
1860 * @inode: inode to wait for
1862 * Waits for all pending direct I/O requests to finish so that we can
1863 * proceed with a truncate or equivalent operation.
1865 * Must be called under a lock that serializes taking new references
1866 * to i_dio_count, usually by inode->i_mutex.
1868 void inode_dio_wait(struct inode *inode)
1870 if (atomic_read(&inode->i_dio_count))
1871 __inode_dio_wait(inode);
1873 EXPORT_SYMBOL(inode_dio_wait);
1876 * inode_dio_done - signal finish of a direct I/O requests
1877 * @inode: inode the direct I/O happens on
1879 * This is called once we've finished processing a direct I/O request,
1880 * and is used to wake up callers waiting for direct I/O to be quiesced.
1882 void inode_dio_done(struct inode *inode)
1884 if (atomic_dec_and_test(&inode->i_dio_count))
1885 wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
1887 EXPORT_SYMBOL(inode_dio_done);
1890 * inode_set_flags - atomically set some inode flags
1892 * Note: the caller should be holding i_mutex, or else be sure that
1893 * they have exclusive access to the inode structure (i.e., while the
1894 * inode is being instantiated). The reason for the cmpxchg() loop
1895 * --- which wouldn't be necessary if all code paths which modify
1896 * i_flags actually followed this rule, is that there is at least one
1897 * code path which doesn't today --- for example,
1898 * __generic_file_aio_write() calls file_remove_suid() without holding
1899 * i_mutex --- so we use cmpxchg() out of an abundance of caution.
1901 * In the long run, i_mutex is overkill, and we should probably look
1902 * at using the i_lock spinlock to protect i_flags, and then make sure
1903 * it is so documented in include/linux/fs.h and that all code follows
1904 * the locking convention!!
1906 void inode_set_flags(struct inode *inode, unsigned int flags,
1909 unsigned int old_flags, new_flags;
1911 WARN_ON_ONCE(flags & ~mask);
1913 old_flags = ACCESS_ONCE(inode->i_flags);
1914 new_flags = (old_flags & ~mask) | flags;
1915 } while (unlikely(cmpxchg(&inode->i_flags, old_flags,
1916 new_flags) != old_flags));
1918 EXPORT_SYMBOL(inode_set_flags);