4 * (C) 1997 Linus Torvalds
9 #include <linux/dcache.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/writeback.h>
13 #include <linux/module.h>
14 #include <linux/backing-dev.h>
15 #include <linux/wait.h>
16 #include <linux/rwsem.h>
17 #include <linux/hash.h>
18 #include <linux/swap.h>
19 #include <linux/security.h>
20 #include <linux/pagemap.h>
21 #include <linux/cdev.h>
22 #include <linux/bootmem.h>
23 #include <linux/fsnotify.h>
24 #include <linux/mount.h>
25 #include <linux/async.h>
26 #include <linux/posix_acl.h>
27 #include <linux/ima.h>
28 #include <linux/cred.h>
31 * inode locking rules.
33 * inode->i_lock protects:
34 * inode->i_state, inode->i_hash, __iget()
35 * inode_lru_lock protects:
36 * inode_lru, inode->i_lru
45 * This is needed for the following functions:
49 * FIXME: remove all knowledge of the buffer layer from this file
51 #include <linux/buffer_head.h>
54 * New inode.c implementation.
56 * This implementation has the basic premise of trying
57 * to be extremely low-overhead and SMP-safe, yet be
58 * simple enough to be "obviously correct".
63 /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
65 /* #define INODE_PARANOIA 1 */
66 /* #define INODE_DEBUG 1 */
69 * Inode lookup is no longer as critical as it used to be:
70 * most of the lookups are going to be through the dcache.
72 #define I_HASHBITS i_hash_shift
73 #define I_HASHMASK i_hash_mask
75 static unsigned int i_hash_mask __read_mostly;
76 static unsigned int i_hash_shift __read_mostly;
79 * Each inode can be on two separate lists. One is
80 * the hash list of the inode, used for lookups. The
81 * other linked list is the "type" list:
82 * "in_use" - valid inode, i_count > 0, i_nlink > 0
83 * "dirty" - as "in_use" but also dirty
84 * "unused" - valid inode, i_count = 0
86 * A "dirty" list is maintained for each super block,
87 * allowing for low-overhead inode sync() operations.
90 static LIST_HEAD(inode_lru);
91 static DEFINE_SPINLOCK(inode_lru_lock);
92 static struct hlist_head *inode_hashtable __read_mostly;
95 * A simple spinlock to protect the list manipulations.
97 * NOTE! You also have to own the lock if you change
98 * the i_state of an inode while it is in use..
100 DEFINE_SPINLOCK(inode_lock);
103 * iprune_sem provides exclusion between the icache shrinking and the
106 * We don't actually need it to protect anything in the umount path,
107 * but only need to cycle through it to make sure any inode that
108 * prune_icache took off the LRU list has been fully torn down by the
109 * time we are past evict_inodes.
111 static DECLARE_RWSEM(iprune_sem);
114 * Statistics gathering..
116 struct inodes_stat_t inodes_stat;
118 static DEFINE_PER_CPU(unsigned int, nr_inodes);
120 static struct kmem_cache *inode_cachep __read_mostly;
122 static int get_nr_inodes(void)
126 for_each_possible_cpu(i)
127 sum += per_cpu(nr_inodes, i);
128 return sum < 0 ? 0 : sum;
131 static inline int get_nr_inodes_unused(void)
133 return inodes_stat.nr_unused;
136 int get_nr_dirty_inodes(void)
138 /* not actually dirty inodes, but a wild approximation */
139 int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
140 return nr_dirty > 0 ? nr_dirty : 0;
144 * Handle nr_inode sysctl
147 int proc_nr_inodes(ctl_table *table, int write,
148 void __user *buffer, size_t *lenp, loff_t *ppos)
150 inodes_stat.nr_inodes = get_nr_inodes();
151 return proc_dointvec(table, write, buffer, lenp, ppos);
156 * inode_init_always - perform inode structure intialisation
157 * @sb: superblock inode belongs to
158 * @inode: inode to initialise
160 * These are initializations that need to be done on every inode
161 * allocation as the fields are not initialised by slab allocation.
163 int inode_init_always(struct super_block *sb, struct inode *inode)
165 static const struct address_space_operations empty_aops;
166 static const struct inode_operations empty_iops;
167 static const struct file_operations empty_fops;
168 struct address_space *const mapping = &inode->i_data;
171 inode->i_blkbits = sb->s_blocksize_bits;
173 atomic_set(&inode->i_count, 1);
174 inode->i_op = &empty_iops;
175 inode->i_fop = &empty_fops;
179 atomic_set(&inode->i_writecount, 0);
183 inode->i_generation = 0;
185 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
187 inode->i_pipe = NULL;
188 inode->i_bdev = NULL;
189 inode->i_cdev = NULL;
191 inode->dirtied_when = 0;
193 if (security_inode_alloc(inode))
195 spin_lock_init(&inode->i_lock);
196 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
198 mutex_init(&inode->i_mutex);
199 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
201 init_rwsem(&inode->i_alloc_sem);
202 lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
204 mapping->a_ops = &empty_aops;
205 mapping->host = inode;
207 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
208 mapping->assoc_mapping = NULL;
209 mapping->backing_dev_info = &default_backing_dev_info;
210 mapping->writeback_index = 0;
213 * If the block_device provides a backing_dev_info for client
214 * inodes then use that. Otherwise the inode share the bdev's
218 struct backing_dev_info *bdi;
220 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
221 mapping->backing_dev_info = bdi;
223 inode->i_private = NULL;
224 inode->i_mapping = mapping;
225 #ifdef CONFIG_FS_POSIX_ACL
226 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
229 #ifdef CONFIG_FSNOTIFY
230 inode->i_fsnotify_mask = 0;
233 this_cpu_inc(nr_inodes);
239 EXPORT_SYMBOL(inode_init_always);
241 static struct inode *alloc_inode(struct super_block *sb)
245 if (sb->s_op->alloc_inode)
246 inode = sb->s_op->alloc_inode(sb);
248 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
253 if (unlikely(inode_init_always(sb, inode))) {
254 if (inode->i_sb->s_op->destroy_inode)
255 inode->i_sb->s_op->destroy_inode(inode);
257 kmem_cache_free(inode_cachep, inode);
264 void free_inode_nonrcu(struct inode *inode)
266 kmem_cache_free(inode_cachep, inode);
268 EXPORT_SYMBOL(free_inode_nonrcu);
270 void __destroy_inode(struct inode *inode)
272 BUG_ON(inode_has_buffers(inode));
273 security_inode_free(inode);
274 fsnotify_inode_delete(inode);
275 #ifdef CONFIG_FS_POSIX_ACL
276 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
277 posix_acl_release(inode->i_acl);
278 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
279 posix_acl_release(inode->i_default_acl);
281 this_cpu_dec(nr_inodes);
283 EXPORT_SYMBOL(__destroy_inode);
285 static void i_callback(struct rcu_head *head)
287 struct inode *inode = container_of(head, struct inode, i_rcu);
288 INIT_LIST_HEAD(&inode->i_dentry);
289 kmem_cache_free(inode_cachep, inode);
292 static void destroy_inode(struct inode *inode)
294 BUG_ON(!list_empty(&inode->i_lru));
295 __destroy_inode(inode);
296 if (inode->i_sb->s_op->destroy_inode)
297 inode->i_sb->s_op->destroy_inode(inode);
299 call_rcu(&inode->i_rcu, i_callback);
302 void address_space_init_once(struct address_space *mapping)
304 memset(mapping, 0, sizeof(*mapping));
305 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
306 spin_lock_init(&mapping->tree_lock);
307 spin_lock_init(&mapping->i_mmap_lock);
308 INIT_LIST_HEAD(&mapping->private_list);
309 spin_lock_init(&mapping->private_lock);
310 INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
311 INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
312 mutex_init(&mapping->unmap_mutex);
314 EXPORT_SYMBOL(address_space_init_once);
317 * These are initializations that only need to be done
318 * once, because the fields are idempotent across use
319 * of the inode, so let the slab aware of that.
321 void inode_init_once(struct inode *inode)
323 memset(inode, 0, sizeof(*inode));
324 INIT_HLIST_NODE(&inode->i_hash);
325 INIT_LIST_HEAD(&inode->i_dentry);
326 INIT_LIST_HEAD(&inode->i_devices);
327 INIT_LIST_HEAD(&inode->i_wb_list);
328 INIT_LIST_HEAD(&inode->i_lru);
329 address_space_init_once(&inode->i_data);
330 i_size_ordered_init(inode);
331 #ifdef CONFIG_FSNOTIFY
332 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
335 EXPORT_SYMBOL(inode_init_once);
337 static void init_once(void *foo)
339 struct inode *inode = (struct inode *) foo;
341 inode_init_once(inode);
345 * inode->i_lock must be held
347 void __iget(struct inode *inode)
349 atomic_inc(&inode->i_count);
353 * get additional reference to inode; caller must already hold one.
355 void ihold(struct inode *inode)
357 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
359 EXPORT_SYMBOL(ihold);
361 static void inode_lru_list_add(struct inode *inode)
363 spin_lock(&inode_lru_lock);
364 if (list_empty(&inode->i_lru)) {
365 list_add(&inode->i_lru, &inode_lru);
366 inodes_stat.nr_unused++;
368 spin_unlock(&inode_lru_lock);
371 static void inode_lru_list_del(struct inode *inode)
373 spin_lock(&inode_lru_lock);
374 if (!list_empty(&inode->i_lru)) {
375 list_del_init(&inode->i_lru);
376 inodes_stat.nr_unused--;
378 spin_unlock(&inode_lru_lock);
381 static inline void __inode_sb_list_add(struct inode *inode)
383 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
387 * inode_sb_list_add - add inode to the superblock list of inodes
388 * @inode: inode to add
390 void inode_sb_list_add(struct inode *inode)
392 spin_lock(&inode_lock);
393 __inode_sb_list_add(inode);
394 spin_unlock(&inode_lock);
396 EXPORT_SYMBOL_GPL(inode_sb_list_add);
398 static inline void __inode_sb_list_del(struct inode *inode)
400 list_del_init(&inode->i_sb_list);
403 static unsigned long hash(struct super_block *sb, unsigned long hashval)
407 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
409 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
410 return tmp & I_HASHMASK;
414 * __insert_inode_hash - hash an inode
415 * @inode: unhashed inode
416 * @hashval: unsigned long value used to locate this object in the
419 * Add an inode to the inode hash for this superblock.
421 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
423 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
425 spin_lock(&inode_lock);
426 spin_lock(&inode->i_lock);
427 hlist_add_head(&inode->i_hash, b);
428 spin_unlock(&inode->i_lock);
429 spin_unlock(&inode_lock);
431 EXPORT_SYMBOL(__insert_inode_hash);
434 * remove_inode_hash - remove an inode from the hash
435 * @inode: inode to unhash
437 * Remove an inode from the superblock.
439 void remove_inode_hash(struct inode *inode)
441 spin_lock(&inode_lock);
442 spin_lock(&inode->i_lock);
443 hlist_del_init(&inode->i_hash);
444 spin_unlock(&inode->i_lock);
445 spin_unlock(&inode_lock);
447 EXPORT_SYMBOL(remove_inode_hash);
449 void end_writeback(struct inode *inode)
452 BUG_ON(inode->i_data.nrpages);
453 BUG_ON(!list_empty(&inode->i_data.private_list));
454 BUG_ON(!(inode->i_state & I_FREEING));
455 BUG_ON(inode->i_state & I_CLEAR);
456 inode_sync_wait(inode);
457 /* don't need i_lock here, no concurrent mods to i_state */
458 inode->i_state = I_FREEING | I_CLEAR;
460 EXPORT_SYMBOL(end_writeback);
463 * Free the inode passed in, removing it from the lists it is still connected
464 * to. We remove any pages still attached to the inode and wait for any IO that
465 * is still in progress before finally destroying the inode.
467 * An inode must already be marked I_FREEING so that we avoid the inode being
468 * moved back onto lists if we race with other code that manipulates the lists
469 * (e.g. writeback_single_inode). The caller is responsible for setting this.
471 * An inode must already be removed from the LRU list before being evicted from
472 * the cache. This should occur atomically with setting the I_FREEING state
473 * flag, so no inodes here should ever be on the LRU when being evicted.
475 static void evict(struct inode *inode)
477 const struct super_operations *op = inode->i_sb->s_op;
479 BUG_ON(!(inode->i_state & I_FREEING));
480 BUG_ON(!list_empty(&inode->i_lru));
482 spin_lock(&inode_lock);
483 list_del_init(&inode->i_wb_list);
484 __inode_sb_list_del(inode);
485 spin_unlock(&inode_lock);
487 if (op->evict_inode) {
488 op->evict_inode(inode);
490 if (inode->i_data.nrpages)
491 truncate_inode_pages(&inode->i_data, 0);
492 end_writeback(inode);
494 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
496 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
499 remove_inode_hash(inode);
501 spin_lock(&inode->i_lock);
502 wake_up_bit(&inode->i_state, __I_NEW);
503 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
504 spin_unlock(&inode->i_lock);
506 destroy_inode(inode);
510 * dispose_list - dispose of the contents of a local list
511 * @head: the head of the list to free
513 * Dispose-list gets a local list with local inodes in it, so it doesn't
514 * need to worry about list corruption and SMP locks.
516 static void dispose_list(struct list_head *head)
518 while (!list_empty(head)) {
521 inode = list_first_entry(head, struct inode, i_lru);
522 list_del_init(&inode->i_lru);
529 * evict_inodes - evict all evictable inodes for a superblock
530 * @sb: superblock to operate on
532 * Make sure that no inodes with zero refcount are retained. This is
533 * called by superblock shutdown after having MS_ACTIVE flag removed,
534 * so any inode reaching zero refcount during or after that call will
535 * be immediately evicted.
537 void evict_inodes(struct super_block *sb)
539 struct inode *inode, *next;
542 spin_lock(&inode_lock);
543 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
544 if (atomic_read(&inode->i_count))
547 spin_lock(&inode->i_lock);
548 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
549 spin_unlock(&inode->i_lock);
553 inode->i_state |= I_FREEING;
554 inode_lru_list_del(inode);
555 spin_unlock(&inode->i_lock);
556 list_add(&inode->i_lru, &dispose);
558 spin_unlock(&inode_lock);
560 dispose_list(&dispose);
563 * Cycle through iprune_sem to make sure any inode that prune_icache
564 * moved off the list before we took the lock has been fully torn
567 down_write(&iprune_sem);
568 up_write(&iprune_sem);
572 * invalidate_inodes - attempt to free all inodes on a superblock
573 * @sb: superblock to operate on
574 * @kill_dirty: flag to guide handling of dirty inodes
576 * Attempts to free all inodes for a given superblock. If there were any
577 * busy inodes return a non-zero value, else zero.
578 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
581 int invalidate_inodes(struct super_block *sb, bool kill_dirty)
584 struct inode *inode, *next;
587 spin_lock(&inode_lock);
588 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
589 spin_lock(&inode->i_lock);
590 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
591 spin_unlock(&inode->i_lock);
594 if (inode->i_state & I_DIRTY && !kill_dirty) {
595 spin_unlock(&inode->i_lock);
599 if (atomic_read(&inode->i_count)) {
600 spin_unlock(&inode->i_lock);
605 inode->i_state |= I_FREEING;
606 inode_lru_list_del(inode);
607 spin_unlock(&inode->i_lock);
608 list_add(&inode->i_lru, &dispose);
610 spin_unlock(&inode_lock);
612 dispose_list(&dispose);
617 static int can_unuse(struct inode *inode)
619 if (inode->i_state & ~I_REFERENCED)
621 if (inode_has_buffers(inode))
623 if (atomic_read(&inode->i_count))
625 if (inode->i_data.nrpages)
631 * Scan `goal' inodes on the unused list for freeable ones. They are moved to a
632 * temporary list and then are freed outside inode_lru_lock by dispose_list().
634 * Any inodes which are pinned purely because of attached pagecache have their
635 * pagecache removed. If the inode has metadata buffers attached to
636 * mapping->private_list then try to remove them.
638 * If the inode has the I_REFERENCED flag set, then it means that it has been
639 * used recently - the flag is set in iput_final(). When we encounter such an
640 * inode, clear the flag and move it to the back of the LRU so it gets another
641 * pass through the LRU before it gets reclaimed. This is necessary because of
642 * the fact we are doing lazy LRU updates to minimise lock contention so the
643 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
644 * with this flag set because they are the inodes that are out of order.
646 static void prune_icache(int nr_to_scan)
650 unsigned long reap = 0;
652 down_read(&iprune_sem);
653 spin_lock(&inode_lock);
654 spin_lock(&inode_lru_lock);
655 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
658 if (list_empty(&inode_lru))
661 inode = list_entry(inode_lru.prev, struct inode, i_lru);
664 * we are inverting the inode_lru_lock/inode->i_lock here,
665 * so use a trylock. If we fail to get the lock, just move the
666 * inode to the back of the list so we don't spin on it.
668 if (!spin_trylock(&inode->i_lock)) {
669 list_move(&inode->i_lru, &inode_lru);
674 * Referenced or dirty inodes are still in use. Give them
675 * another pass through the LRU as we canot reclaim them now.
677 if (atomic_read(&inode->i_count) ||
678 (inode->i_state & ~I_REFERENCED)) {
679 spin_unlock(&inode->i_lock);
680 list_del_init(&inode->i_lru);
681 inodes_stat.nr_unused--;
685 /* recently referenced inodes get one more pass */
686 if (inode->i_state & I_REFERENCED) {
687 inode->i_state &= ~I_REFERENCED;
688 spin_unlock(&inode->i_lock);
689 list_move(&inode->i_lru, &inode_lru);
692 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
694 spin_unlock(&inode->i_lock);
695 spin_unlock(&inode_lru_lock);
696 spin_unlock(&inode_lock);
697 if (remove_inode_buffers(inode))
698 reap += invalidate_mapping_pages(&inode->i_data,
701 spin_lock(&inode_lock);
702 spin_lock(&inode_lru_lock);
704 if (inode != list_entry(inode_lru.next,
705 struct inode, i_lru))
706 continue; /* wrong inode or list_empty */
707 /* avoid lock inversions with trylock */
708 if (!spin_trylock(&inode->i_lock))
710 if (!can_unuse(inode)) {
711 spin_unlock(&inode->i_lock);
715 WARN_ON(inode->i_state & I_NEW);
716 inode->i_state |= I_FREEING;
717 spin_unlock(&inode->i_lock);
719 list_move(&inode->i_lru, &freeable);
720 inodes_stat.nr_unused--;
722 if (current_is_kswapd())
723 __count_vm_events(KSWAPD_INODESTEAL, reap);
725 __count_vm_events(PGINODESTEAL, reap);
726 spin_unlock(&inode_lru_lock);
727 spin_unlock(&inode_lock);
729 dispose_list(&freeable);
730 up_read(&iprune_sem);
734 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
735 * "unused" means that no dentries are referring to the inodes: the files are
736 * not open and the dcache references to those inodes have already been
739 * This function is passed the number of inodes to scan, and it returns the
740 * total number of remaining possibly-reclaimable inodes.
742 static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
746 * Nasty deadlock avoidance. We may hold various FS locks,
747 * and we don't want to recurse into the FS that called us
748 * in clear_inode() and friends..
750 if (!(gfp_mask & __GFP_FS))
754 return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
757 static struct shrinker icache_shrinker = {
758 .shrink = shrink_icache_memory,
759 .seeks = DEFAULT_SEEKS,
762 static void __wait_on_freeing_inode(struct inode *inode);
764 * Called with the inode lock held.
766 static struct inode *find_inode(struct super_block *sb,
767 struct hlist_head *head,
768 int (*test)(struct inode *, void *),
771 struct hlist_node *node;
772 struct inode *inode = NULL;
775 hlist_for_each_entry(inode, node, head, i_hash) {
776 if (inode->i_sb != sb)
778 if (!test(inode, data))
780 spin_lock(&inode->i_lock);
781 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
782 __wait_on_freeing_inode(inode);
786 spin_unlock(&inode->i_lock);
793 * find_inode_fast is the fast path version of find_inode, see the comment at
794 * iget_locked for details.
796 static struct inode *find_inode_fast(struct super_block *sb,
797 struct hlist_head *head, unsigned long ino)
799 struct hlist_node *node;
800 struct inode *inode = NULL;
803 hlist_for_each_entry(inode, node, head, i_hash) {
804 if (inode->i_ino != ino)
806 if (inode->i_sb != sb)
808 spin_lock(&inode->i_lock);
809 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
810 __wait_on_freeing_inode(inode);
814 spin_unlock(&inode->i_lock);
821 * Each cpu owns a range of LAST_INO_BATCH numbers.
822 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
823 * to renew the exhausted range.
825 * This does not significantly increase overflow rate because every CPU can
826 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
827 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
828 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
829 * overflow rate by 2x, which does not seem too significant.
831 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
832 * error if st_ino won't fit in target struct field. Use 32bit counter
833 * here to attempt to avoid that.
835 #define LAST_INO_BATCH 1024
836 static DEFINE_PER_CPU(unsigned int, last_ino);
838 unsigned int get_next_ino(void)
840 unsigned int *p = &get_cpu_var(last_ino);
841 unsigned int res = *p;
844 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
845 static atomic_t shared_last_ino;
846 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
848 res = next - LAST_INO_BATCH;
853 put_cpu_var(last_ino);
856 EXPORT_SYMBOL(get_next_ino);
859 * new_inode - obtain an inode
862 * Allocates a new inode for given superblock. The default gfp_mask
863 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
864 * If HIGHMEM pages are unsuitable or it is known that pages allocated
865 * for the page cache are not reclaimable or migratable,
866 * mapping_set_gfp_mask() must be called with suitable flags on the
867 * newly created inode's mapping
870 struct inode *new_inode(struct super_block *sb)
874 spin_lock_prefetch(&inode_lock);
876 inode = alloc_inode(sb);
878 spin_lock(&inode_lock);
879 spin_lock(&inode->i_lock);
881 spin_unlock(&inode->i_lock);
882 __inode_sb_list_add(inode);
883 spin_unlock(&inode_lock);
887 EXPORT_SYMBOL(new_inode);
890 * unlock_new_inode - clear the I_NEW state and wake up any waiters
891 * @inode: new inode to unlock
893 * Called when the inode is fully initialised to clear the new state of the
894 * inode and wake up anyone waiting for the inode to finish initialisation.
896 void unlock_new_inode(struct inode *inode)
898 #ifdef CONFIG_DEBUG_LOCK_ALLOC
899 if (S_ISDIR(inode->i_mode)) {
900 struct file_system_type *type = inode->i_sb->s_type;
902 /* Set new key only if filesystem hasn't already changed it */
903 if (!lockdep_match_class(&inode->i_mutex,
904 &type->i_mutex_key)) {
906 * ensure nobody is actually holding i_mutex
908 mutex_destroy(&inode->i_mutex);
909 mutex_init(&inode->i_mutex);
910 lockdep_set_class(&inode->i_mutex,
911 &type->i_mutex_dir_key);
915 spin_lock(&inode->i_lock);
916 WARN_ON(!(inode->i_state & I_NEW));
917 inode->i_state &= ~I_NEW;
918 wake_up_bit(&inode->i_state, __I_NEW);
919 spin_unlock(&inode->i_lock);
921 EXPORT_SYMBOL(unlock_new_inode);
924 * This is called without the inode lock held.. Be careful.
926 * We no longer cache the sb_flags in i_flags - see fs.h
927 * -- rmk@arm.uk.linux.org
929 static struct inode *get_new_inode(struct super_block *sb,
930 struct hlist_head *head,
931 int (*test)(struct inode *, void *),
932 int (*set)(struct inode *, void *),
937 inode = alloc_inode(sb);
941 spin_lock(&inode_lock);
942 /* We released the lock, so.. */
943 old = find_inode(sb, head, test, data);
945 if (set(inode, data))
948 spin_lock(&inode->i_lock);
949 inode->i_state = I_NEW;
950 hlist_add_head(&inode->i_hash, head);
951 spin_unlock(&inode->i_lock);
952 __inode_sb_list_add(inode);
953 spin_unlock(&inode_lock);
955 /* Return the locked inode with I_NEW set, the
956 * caller is responsible for filling in the contents
962 * Uhhuh, somebody else created the same inode under
963 * us. Use the old inode instead of the one we just
966 spin_unlock(&inode_lock);
967 destroy_inode(inode);
969 wait_on_inode(inode);
974 spin_unlock(&inode_lock);
975 destroy_inode(inode);
980 * get_new_inode_fast is the fast path version of get_new_inode, see the
981 * comment at iget_locked for details.
983 static struct inode *get_new_inode_fast(struct super_block *sb,
984 struct hlist_head *head, unsigned long ino)
988 inode = alloc_inode(sb);
992 spin_lock(&inode_lock);
993 /* We released the lock, so.. */
994 old = find_inode_fast(sb, head, ino);
997 spin_lock(&inode->i_lock);
998 inode->i_state = I_NEW;
999 hlist_add_head(&inode->i_hash, head);
1000 spin_unlock(&inode->i_lock);
1001 __inode_sb_list_add(inode);
1002 spin_unlock(&inode_lock);
1004 /* Return the locked inode with I_NEW set, the
1005 * caller is responsible for filling in the contents
1011 * Uhhuh, somebody else created the same inode under
1012 * us. Use the old inode instead of the one we just
1015 spin_unlock(&inode_lock);
1016 destroy_inode(inode);
1018 wait_on_inode(inode);
1024 * search the inode cache for a matching inode number.
1025 * If we find one, then the inode number we are trying to
1026 * allocate is not unique and so we should not use it.
1028 * Returns 1 if the inode number is unique, 0 if it is not.
1030 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1032 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1033 struct hlist_node *node;
1034 struct inode *inode;
1036 hlist_for_each_entry(inode, node, b, i_hash) {
1037 if (inode->i_ino == ino && inode->i_sb == sb)
1045 * iunique - get a unique inode number
1047 * @max_reserved: highest reserved inode number
1049 * Obtain an inode number that is unique on the system for a given
1050 * superblock. This is used by file systems that have no natural
1051 * permanent inode numbering system. An inode number is returned that
1052 * is higher than the reserved limit but unique.
1055 * With a large number of inodes live on the file system this function
1056 * currently becomes quite slow.
1058 ino_t iunique(struct super_block *sb, ino_t max_reserved)
1061 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1062 * error if st_ino won't fit in target struct field. Use 32bit counter
1063 * here to attempt to avoid that.
1065 static DEFINE_SPINLOCK(iunique_lock);
1066 static unsigned int counter;
1069 spin_lock(&inode_lock);
1070 spin_lock(&iunique_lock);
1072 if (counter <= max_reserved)
1073 counter = max_reserved + 1;
1075 } while (!test_inode_iunique(sb, res));
1076 spin_unlock(&iunique_lock);
1077 spin_unlock(&inode_lock);
1081 EXPORT_SYMBOL(iunique);
1083 struct inode *igrab(struct inode *inode)
1085 spin_lock(&inode_lock);
1086 spin_lock(&inode->i_lock);
1087 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1089 spin_unlock(&inode->i_lock);
1091 spin_unlock(&inode->i_lock);
1093 * Handle the case where s_op->clear_inode is not been
1094 * called yet, and somebody is calling igrab
1095 * while the inode is getting freed.
1099 spin_unlock(&inode_lock);
1102 EXPORT_SYMBOL(igrab);
1105 * ifind - internal function, you want ilookup5() or iget5().
1106 * @sb: super block of file system to search
1107 * @head: the head of the list to search
1108 * @test: callback used for comparisons between inodes
1109 * @data: opaque data pointer to pass to @test
1110 * @wait: if true wait for the inode to be unlocked, if false do not
1112 * ifind() searches for the inode specified by @data in the inode
1113 * cache. This is a generalized version of ifind_fast() for file systems where
1114 * the inode number is not sufficient for unique identification of an inode.
1116 * If the inode is in the cache, the inode is returned with an incremented
1119 * Otherwise NULL is returned.
1121 * Note, @test is called with the inode_lock held, so can't sleep.
1123 static struct inode *ifind(struct super_block *sb,
1124 struct hlist_head *head, int (*test)(struct inode *, void *),
1125 void *data, const int wait)
1127 struct inode *inode;
1129 spin_lock(&inode_lock);
1130 inode = find_inode(sb, head, test, data);
1132 spin_unlock(&inode_lock);
1134 wait_on_inode(inode);
1137 spin_unlock(&inode_lock);
1142 * ifind_fast - internal function, you want ilookup() or iget().
1143 * @sb: super block of file system to search
1144 * @head: head of the list to search
1145 * @ino: inode number to search for
1147 * ifind_fast() searches for the inode @ino in the inode cache. This is for
1148 * file systems where the inode number is sufficient for unique identification
1151 * If the inode is in the cache, the inode is returned with an incremented
1154 * Otherwise NULL is returned.
1156 static struct inode *ifind_fast(struct super_block *sb,
1157 struct hlist_head *head, unsigned long ino)
1159 struct inode *inode;
1161 spin_lock(&inode_lock);
1162 inode = find_inode_fast(sb, head, ino);
1164 spin_unlock(&inode_lock);
1165 wait_on_inode(inode);
1168 spin_unlock(&inode_lock);
1173 * ilookup5_nowait - search for an inode in the inode cache
1174 * @sb: super block of file system to search
1175 * @hashval: hash value (usually inode number) to search for
1176 * @test: callback used for comparisons between inodes
1177 * @data: opaque data pointer to pass to @test
1179 * ilookup5() uses ifind() to search for the inode specified by @hashval and
1180 * @data in the inode cache. This is a generalized version of ilookup() for
1181 * file systems where the inode number is not sufficient for unique
1182 * identification of an inode.
1184 * If the inode is in the cache, the inode is returned with an incremented
1185 * reference count. Note, the inode lock is not waited upon so you have to be
1186 * very careful what you do with the returned inode. You probably should be
1187 * using ilookup5() instead.
1189 * Otherwise NULL is returned.
1191 * Note, @test is called with the inode_lock held, so can't sleep.
1193 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1194 int (*test)(struct inode *, void *), void *data)
1196 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1198 return ifind(sb, head, test, data, 0);
1200 EXPORT_SYMBOL(ilookup5_nowait);
1203 * ilookup5 - search for an inode in the inode cache
1204 * @sb: super block of file system to search
1205 * @hashval: hash value (usually inode number) to search for
1206 * @test: callback used for comparisons between inodes
1207 * @data: opaque data pointer to pass to @test
1209 * ilookup5() uses ifind() to search for the inode specified by @hashval and
1210 * @data in the inode cache. This is a generalized version of ilookup() for
1211 * file systems where the inode number is not sufficient for unique
1212 * identification of an inode.
1214 * If the inode is in the cache, the inode lock is waited upon and the inode is
1215 * returned with an incremented reference count.
1217 * Otherwise NULL is returned.
1219 * Note, @test is called with the inode_lock held, so can't sleep.
1221 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1222 int (*test)(struct inode *, void *), void *data)
1224 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1226 return ifind(sb, head, test, data, 1);
1228 EXPORT_SYMBOL(ilookup5);
1231 * ilookup - search for an inode in the inode cache
1232 * @sb: super block of file system to search
1233 * @ino: inode number to search for
1235 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
1236 * This is for file systems where the inode number is sufficient for unique
1237 * identification of an inode.
1239 * If the inode is in the cache, the inode is returned with an incremented
1242 * Otherwise NULL is returned.
1244 struct inode *ilookup(struct super_block *sb, unsigned long ino)
1246 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1248 return ifind_fast(sb, head, ino);
1250 EXPORT_SYMBOL(ilookup);
1253 * iget5_locked - obtain an inode from a mounted file system
1254 * @sb: super block of file system
1255 * @hashval: hash value (usually inode number) to get
1256 * @test: callback used for comparisons between inodes
1257 * @set: callback used to initialize a new struct inode
1258 * @data: opaque data pointer to pass to @test and @set
1260 * iget5_locked() uses ifind() to search for the inode specified by @hashval
1261 * and @data in the inode cache and if present it is returned with an increased
1262 * reference count. This is a generalized version of iget_locked() for file
1263 * systems where the inode number is not sufficient for unique identification
1266 * If the inode is not in cache, get_new_inode() is called to allocate a new
1267 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
1268 * file system gets to fill it in before unlocking it via unlock_new_inode().
1270 * Note both @test and @set are called with the inode_lock held, so can't sleep.
1272 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1273 int (*test)(struct inode *, void *),
1274 int (*set)(struct inode *, void *), void *data)
1276 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1277 struct inode *inode;
1279 inode = ifind(sb, head, test, data, 1);
1283 * get_new_inode() will do the right thing, re-trying the search
1284 * in case it had to block at any point.
1286 return get_new_inode(sb, head, test, set, data);
1288 EXPORT_SYMBOL(iget5_locked);
1291 * iget_locked - obtain an inode from a mounted file system
1292 * @sb: super block of file system
1293 * @ino: inode number to get
1295 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
1296 * the inode cache and if present it is returned with an increased reference
1297 * count. This is for file systems where the inode number is sufficient for
1298 * unique identification of an inode.
1300 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
1301 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
1302 * The file system gets to fill it in before unlocking it via
1303 * unlock_new_inode().
1305 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1307 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1308 struct inode *inode;
1310 inode = ifind_fast(sb, head, ino);
1314 * get_new_inode_fast() will do the right thing, re-trying the search
1315 * in case it had to block at any point.
1317 return get_new_inode_fast(sb, head, ino);
1319 EXPORT_SYMBOL(iget_locked);
1321 int insert_inode_locked(struct inode *inode)
1323 struct super_block *sb = inode->i_sb;
1324 ino_t ino = inode->i_ino;
1325 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1328 struct hlist_node *node;
1329 struct inode *old = NULL;
1330 spin_lock(&inode_lock);
1331 hlist_for_each_entry(old, node, head, i_hash) {
1332 if (old->i_ino != ino)
1334 if (old->i_sb != sb)
1336 spin_lock(&old->i_lock);
1337 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1338 spin_unlock(&old->i_lock);
1343 if (likely(!node)) {
1344 spin_lock(&inode->i_lock);
1345 inode->i_state |= I_NEW;
1346 hlist_add_head(&inode->i_hash, head);
1347 spin_unlock(&inode->i_lock);
1348 spin_unlock(&inode_lock);
1352 spin_unlock(&old->i_lock);
1353 spin_unlock(&inode_lock);
1355 if (unlikely(!inode_unhashed(old))) {
1362 EXPORT_SYMBOL(insert_inode_locked);
1364 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1365 int (*test)(struct inode *, void *), void *data)
1367 struct super_block *sb = inode->i_sb;
1368 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1371 struct hlist_node *node;
1372 struct inode *old = NULL;
1374 spin_lock(&inode_lock);
1375 hlist_for_each_entry(old, node, head, i_hash) {
1376 if (old->i_sb != sb)
1378 if (!test(old, data))
1380 spin_lock(&old->i_lock);
1381 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1382 spin_unlock(&old->i_lock);
1387 if (likely(!node)) {
1388 spin_lock(&inode->i_lock);
1389 inode->i_state |= I_NEW;
1390 hlist_add_head(&inode->i_hash, head);
1391 spin_unlock(&inode->i_lock);
1392 spin_unlock(&inode_lock);
1396 spin_unlock(&old->i_lock);
1397 spin_unlock(&inode_lock);
1399 if (unlikely(!inode_unhashed(old))) {
1406 EXPORT_SYMBOL(insert_inode_locked4);
1409 int generic_delete_inode(struct inode *inode)
1413 EXPORT_SYMBOL(generic_delete_inode);
1416 * Normal UNIX filesystem behaviour: delete the
1417 * inode when the usage count drops to zero, and
1420 int generic_drop_inode(struct inode *inode)
1422 return !inode->i_nlink || inode_unhashed(inode);
1424 EXPORT_SYMBOL_GPL(generic_drop_inode);
1427 * Called when we're dropping the last reference
1430 * Call the FS "drop_inode()" function, defaulting to
1431 * the legacy UNIX filesystem behaviour. If it tells
1432 * us to evict inode, do so. Otherwise, retain inode
1433 * in cache if fs is alive, sync and evict if fs is
1436 static void iput_final(struct inode *inode)
1438 struct super_block *sb = inode->i_sb;
1439 const struct super_operations *op = inode->i_sb->s_op;
1442 spin_lock(&inode->i_lock);
1443 WARN_ON(inode->i_state & I_NEW);
1445 if (op && op->drop_inode)
1446 drop = op->drop_inode(inode);
1448 drop = generic_drop_inode(inode);
1450 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1451 inode->i_state |= I_REFERENCED;
1452 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
1453 inode_lru_list_add(inode);
1454 spin_unlock(&inode->i_lock);
1455 spin_unlock(&inode_lock);
1460 inode->i_state |= I_WILL_FREE;
1461 spin_unlock(&inode->i_lock);
1462 spin_unlock(&inode_lock);
1463 write_inode_now(inode, 1);
1464 spin_lock(&inode_lock);
1465 spin_lock(&inode->i_lock);
1466 WARN_ON(inode->i_state & I_NEW);
1467 inode->i_state &= ~I_WILL_FREE;
1470 inode->i_state |= I_FREEING;
1471 inode_lru_list_del(inode);
1472 spin_unlock(&inode->i_lock);
1473 spin_unlock(&inode_lock);
1479 * iput - put an inode
1480 * @inode: inode to put
1482 * Puts an inode, dropping its usage count. If the inode use count hits
1483 * zero, the inode is then freed and may also be destroyed.
1485 * Consequently, iput() can sleep.
1487 void iput(struct inode *inode)
1490 BUG_ON(inode->i_state & I_CLEAR);
1492 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1496 EXPORT_SYMBOL(iput);
1499 * bmap - find a block number in a file
1500 * @inode: inode of file
1501 * @block: block to find
1503 * Returns the block number on the device holding the inode that
1504 * is the disk block number for the block of the file requested.
1505 * That is, asked for block 4 of inode 1 the function will return the
1506 * disk block relative to the disk start that holds that block of the
1509 sector_t bmap(struct inode *inode, sector_t block)
1512 if (inode->i_mapping->a_ops->bmap)
1513 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1516 EXPORT_SYMBOL(bmap);
1519 * With relative atime, only update atime if the previous atime is
1520 * earlier than either the ctime or mtime or if at least a day has
1521 * passed since the last atime update.
1523 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1524 struct timespec now)
1527 if (!(mnt->mnt_flags & MNT_RELATIME))
1530 * Is mtime younger than atime? If yes, update atime:
1532 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1535 * Is ctime younger than atime? If yes, update atime:
1537 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1541 * Is the previous atime value older than a day? If yes,
1544 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1547 * Good, we can skip the atime update:
1553 * touch_atime - update the access time
1554 * @mnt: mount the inode is accessed on
1555 * @dentry: dentry accessed
1557 * Update the accessed time on an inode and mark it for writeback.
1558 * This function automatically handles read only file systems and media,
1559 * as well as the "noatime" flag and inode specific "noatime" markers.
1561 void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1563 struct inode *inode = dentry->d_inode;
1564 struct timespec now;
1566 if (inode->i_flags & S_NOATIME)
1568 if (IS_NOATIME(inode))
1570 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1573 if (mnt->mnt_flags & MNT_NOATIME)
1575 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1578 now = current_fs_time(inode->i_sb);
1580 if (!relatime_need_update(mnt, inode, now))
1583 if (timespec_equal(&inode->i_atime, &now))
1586 if (mnt_want_write(mnt))
1589 inode->i_atime = now;
1590 mark_inode_dirty_sync(inode);
1591 mnt_drop_write(mnt);
1593 EXPORT_SYMBOL(touch_atime);
1596 * file_update_time - update mtime and ctime time
1597 * @file: file accessed
1599 * Update the mtime and ctime members of an inode and mark the inode
1600 * for writeback. Note that this function is meant exclusively for
1601 * usage in the file write path of filesystems, and filesystems may
1602 * choose to explicitly ignore update via this function with the
1603 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1604 * timestamps are handled by the server.
1607 void file_update_time(struct file *file)
1609 struct inode *inode = file->f_path.dentry->d_inode;
1610 struct timespec now;
1611 enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
1613 /* First try to exhaust all avenues to not sync */
1614 if (IS_NOCMTIME(inode))
1617 now = current_fs_time(inode->i_sb);
1618 if (!timespec_equal(&inode->i_mtime, &now))
1621 if (!timespec_equal(&inode->i_ctime, &now))
1624 if (IS_I_VERSION(inode))
1625 sync_it |= S_VERSION;
1630 /* Finally allowed to write? Takes lock. */
1631 if (mnt_want_write_file(file))
1634 /* Only change inode inside the lock region */
1635 if (sync_it & S_VERSION)
1636 inode_inc_iversion(inode);
1637 if (sync_it & S_CTIME)
1638 inode->i_ctime = now;
1639 if (sync_it & S_MTIME)
1640 inode->i_mtime = now;
1641 mark_inode_dirty_sync(inode);
1642 mnt_drop_write(file->f_path.mnt);
1644 EXPORT_SYMBOL(file_update_time);
1646 int inode_needs_sync(struct inode *inode)
1650 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1654 EXPORT_SYMBOL(inode_needs_sync);
1656 int inode_wait(void *word)
1661 EXPORT_SYMBOL(inode_wait);
1664 * If we try to find an inode in the inode hash while it is being
1665 * deleted, we have to wait until the filesystem completes its
1666 * deletion before reporting that it isn't found. This function waits
1667 * until the deletion _might_ have completed. Callers are responsible
1668 * to recheck inode state.
1670 * It doesn't matter if I_NEW is not set initially, a call to
1671 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1674 static void __wait_on_freeing_inode(struct inode *inode)
1676 wait_queue_head_t *wq;
1677 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1678 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1679 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1680 spin_unlock(&inode->i_lock);
1681 spin_unlock(&inode_lock);
1683 finish_wait(wq, &wait.wait);
1684 spin_lock(&inode_lock);
1687 static __initdata unsigned long ihash_entries;
1688 static int __init set_ihash_entries(char *str)
1692 ihash_entries = simple_strtoul(str, &str, 0);
1695 __setup("ihash_entries=", set_ihash_entries);
1698 * Initialize the waitqueues and inode hash table.
1700 void __init inode_init_early(void)
1704 /* If hashes are distributed across NUMA nodes, defer
1705 * hash allocation until vmalloc space is available.
1711 alloc_large_system_hash("Inode-cache",
1712 sizeof(struct hlist_head),
1720 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1721 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1724 void __init inode_init(void)
1728 /* inode slab cache */
1729 inode_cachep = kmem_cache_create("inode_cache",
1730 sizeof(struct inode),
1732 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1735 register_shrinker(&icache_shrinker);
1737 /* Hash may have been set up in inode_init_early */
1742 alloc_large_system_hash("Inode-cache",
1743 sizeof(struct hlist_head),
1751 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1752 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1755 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1757 inode->i_mode = mode;
1758 if (S_ISCHR(mode)) {
1759 inode->i_fop = &def_chr_fops;
1760 inode->i_rdev = rdev;
1761 } else if (S_ISBLK(mode)) {
1762 inode->i_fop = &def_blk_fops;
1763 inode->i_rdev = rdev;
1764 } else if (S_ISFIFO(mode))
1765 inode->i_fop = &def_fifo_fops;
1766 else if (S_ISSOCK(mode))
1767 inode->i_fop = &bad_sock_fops;
1769 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1770 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1773 EXPORT_SYMBOL(init_special_inode);
1776 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1778 * @dir: Directory inode
1779 * @mode: mode of the new inode
1781 void inode_init_owner(struct inode *inode, const struct inode *dir,
1784 inode->i_uid = current_fsuid();
1785 if (dir && dir->i_mode & S_ISGID) {
1786 inode->i_gid = dir->i_gid;
1790 inode->i_gid = current_fsgid();
1791 inode->i_mode = mode;
1793 EXPORT_SYMBOL(inode_init_owner);
1796 * inode_owner_or_capable - check current task permissions to inode
1797 * @inode: inode being checked
1799 * Return true if current either has CAP_FOWNER to the inode, or
1802 bool inode_owner_or_capable(const struct inode *inode)
1804 struct user_namespace *ns = inode_userns(inode);
1806 if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
1808 if (ns_capable(ns, CAP_FOWNER))
1812 EXPORT_SYMBOL(inode_owner_or_capable);