fs/inode.c

#include <linux/export.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/cdev.h>
#include <linux/bootmem.h>
#include <linux/fsnotify.h>
#include <linux/mount.h>
#include <linux/posix_acl.h>
#include <linux/prefetch.h>
#include <linux/buffer_head.h> 
#include <linux/ratelimit.h>
#include "internal.h"


static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
static struct hlist_head *inode_hashtable __read_mostly;
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);

__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);

const struct address_space_operations empty_aops = {
};
EXPORT_SYMBOL(empty_aops);

struct inodes_stat_t inodes_stat;

static DEFINE_PER_CPU(unsigned int, nr_inodes);
static DEFINE_PER_CPU(unsigned int, nr_unused);

static struct kmem_cache *inode_cachep __read_mostly;

static int get_nr_inodes(void)
{
	int i;
	int sum = 0;
	for_each_possible_cpu(i)
		sum += per_cpu(nr_inodes, i);
	return sum < 0 ? 0 : sum;
}

static inline int get_nr_inodes_unused(void)
{
	int i;
	int sum = 0;
	for_each_possible_cpu(i)
		sum += per_cpu(nr_unused, i);
	return sum < 0 ? 0 : sum;
}

int get_nr_dirty_inodes(void)
{
	
	int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
	return nr_dirty > 0 ? nr_dirty : 0;
}

#ifdef CONFIG_SYSCTL
int proc_nr_inodes(ctl_table *table, int write,
		   void __user *buffer, size_t *lenp, loff_t *ppos)
{
	inodes_stat.nr_inodes = get_nr_inodes();
	inodes_stat.nr_unused = get_nr_inodes_unused();
	return proc_dointvec(table, write, buffer, lenp, ppos);
}
#endif

int inode_init_always(struct super_block *sb, struct inode *inode)
{
	static const struct inode_operations empty_iops;
	static const struct file_operations empty_fops;
	struct address_space *const mapping = &inode->i_data;

	inode->i_sb = sb;
	inode->i_blkbits = sb->s_blocksize_bits;
	inode->i_flags = 0;
	atomic_set(&inode->i_count, 1);
	inode->i_op = &empty_iops;
	inode->i_fop = &empty_fops;
	inode->__i_nlink = 1;
	inode->i_opflags = 0;
	inode->i_uid = 0;
	inode->i_gid = 0;
	atomic_set(&inode->i_writecount, 0);
	inode->i_size = 0;
	inode->i_blocks = 0;
	inode->i_bytes = 0;
	inode->i_generation = 0;
#ifdef CONFIG_QUOTA
	memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
#endif
	inode->i_pipe = NULL;
	inode->i_bdev = NULL;
	inode->i_cdev = NULL;
	inode->i_rdev = 0;
	inode->dirtied_when = 0;

	if (security_inode_alloc(inode))
		goto out;
	spin_lock_init(&inode->i_lock);
	lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);

	mutex_init(&inode->i_mutex);
	lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);

	atomic_set(&inode->i_dio_count, 0);

	mapping->a_ops = &empty_aops;
	mapping->host = inode;
	mapping->flags = 0;
	mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
	mapping->assoc_mapping = NULL;
	mapping->backing_dev_info = &default_backing_dev_info;
	mapping->writeback_index = 0;

	if (sb->s_bdev) {
		struct backing_dev_info *bdi;

		bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
		mapping->backing_dev_info = bdi;
	}
	inode->i_private = NULL;
	inode->i_mapping = mapping;
	INIT_LIST_HEAD(&inode->i_dentry);	
#ifdef CONFIG_FS_POSIX_ACL
	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
#endif

#ifdef CONFIG_FSNOTIFY
	inode->i_fsnotify_mask = 0;
#endif

	this_cpu_inc(nr_inodes);

	return 0;
out:
	return -ENOMEM;
}
EXPORT_SYMBOL(inode_init_always);

static struct inode *alloc_inode(struct super_block *sb)
{
	struct inode *inode;

	if (sb->s_op->alloc_inode)
		inode = sb->s_op->alloc_inode(sb);
	else
		inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);

	if (!inode)
		return NULL;

	if (unlikely(inode_init_always(sb, inode))) {
		if (inode->i_sb->s_op->destroy_inode)
			inode->i_sb->s_op->destroy_inode(inode);
		else
			kmem_cache_free(inode_cachep, inode);
		return NULL;
	}

	return inode;
}

void free_inode_nonrcu(struct inode *inode)
{
	kmem_cache_free(inode_cachep, inode);
}
EXPORT_SYMBOL(free_inode_nonrcu);

void __destroy_inode(struct inode *inode)
{
	BUG_ON(inode_has_buffers(inode));
	security_inode_free(inode);
	fsnotify_inode_delete(inode);
	if (!inode->i_nlink) {
		WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
		atomic_long_dec(&inode->i_sb->s_remove_count);
	}

#ifdef CONFIG_FS_POSIX_ACL
	if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
		posix_acl_release(inode->i_acl);
	if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
		posix_acl_release(inode->i_default_acl);
#endif
	this_cpu_dec(nr_inodes);
}
EXPORT_SYMBOL(__destroy_inode);

static void i_callback(struct rcu_head *head)
{
	struct inode *inode = container_of(head, struct inode, i_rcu);
	kmem_cache_free(inode_cachep, inode);
}

static void destroy_inode(struct inode *inode)
{
	BUG_ON(!list_empty(&inode->i_lru));
	__destroy_inode(inode);
	if (inode->i_sb->s_op->destroy_inode)
		inode->i_sb->s_op->destroy_inode(inode);
	else
		call_rcu(&inode->i_rcu, i_callback);
}

void drop_nlink(struct inode *inode)
{
	WARN_ON(inode->i_nlink == 0);
	inode->__i_nlink--;
	if (!inode->i_nlink)
		atomic_long_inc(&inode->i_sb->s_remove_count);
}
EXPORT_SYMBOL(drop_nlink);

void clear_nlink(struct inode *inode)
{
	if (inode->i_nlink) {
		inode->__i_nlink = 0;
		atomic_long_inc(&inode->i_sb->s_remove_count);
	}
}
EXPORT_SYMBOL(clear_nlink);

void set_nlink(struct inode *inode, unsigned int nlink)
{
	if (!nlink) {
		clear_nlink(inode);
	} else {
		
		if (inode->i_nlink == 0)
			atomic_long_dec(&inode->i_sb->s_remove_count);

		inode->__i_nlink = nlink;
	}
}
EXPORT_SYMBOL(set_nlink);

void inc_nlink(struct inode *inode)
{
	if (WARN_ON(inode->i_nlink == 0))
		atomic_long_dec(&inode->i_sb->s_remove_count);

	inode->__i_nlink++;
}
EXPORT_SYMBOL(inc_nlink);

void address_space_init_once(struct address_space *mapping)
{
	memset(mapping, 0, sizeof(*mapping));
	INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
	spin_lock_init(&mapping->tree_lock);
	mutex_init(&mapping->i_mmap_mutex);
	INIT_LIST_HEAD(&mapping->private_list);
	spin_lock_init(&mapping->private_lock);
	INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
	INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
}
EXPORT_SYMBOL(address_space_init_once);

void inode_init_once(struct inode *inode)
{
	memset(inode, 0, sizeof(*inode));
	INIT_HLIST_NODE(&inode->i_hash);
	INIT_LIST_HEAD(&inode->i_devices);
	INIT_LIST_HEAD(&inode->i_wb_list);
	INIT_LIST_HEAD(&inode->i_lru);
	address_space_init_once(&inode->i_data);
	i_size_ordered_init(inode);
#ifdef CONFIG_FSNOTIFY
	INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
#endif
}
EXPORT_SYMBOL(inode_init_once);

static void init_once(void *foo)
{
	struct inode *inode = (struct inode *) foo;

	inode_init_once(inode);
}

void __iget(struct inode *inode)
{
	atomic_inc(&inode->i_count);
}

void ihold(struct inode *inode)
{
	WARN_ON(atomic_inc_return(&inode->i_count) < 2);
}
EXPORT_SYMBOL(ihold);

static void inode_lru_list_add(struct inode *inode)
{
	spin_lock(&inode->i_sb->s_inode_lru_lock);
	if (list_empty(&inode->i_lru)) {
		list_add(&inode->i_lru, &inode->i_sb->s_inode_lru);
		inode->i_sb->s_nr_inodes_unused++;
		this_cpu_inc(nr_unused);
	}
	spin_unlock(&inode->i_sb->s_inode_lru_lock);
}

static void inode_lru_list_del(struct inode *inode)
{
	spin_lock(&inode->i_sb->s_inode_lru_lock);
	if (!list_empty(&inode->i_lru)) {
		list_del_init(&inode->i_lru);
		inode->i_sb->s_nr_inodes_unused--;
		this_cpu_dec(nr_unused);
	}
	spin_unlock(&inode->i_sb->s_inode_lru_lock);
}

void inode_sb_list_add(struct inode *inode)
{
	spin_lock(&inode_sb_list_lock);
	list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
	spin_unlock(&inode_sb_list_lock);
}
EXPORT_SYMBOL_GPL(inode_sb_list_add);

static inline void inode_sb_list_del(struct inode *inode)
{
	if (!list_empty(&inode->i_sb_list)) {
		spin_lock(&inode_sb_list_lock);
		list_del_init(&inode->i_sb_list);
		spin_unlock(&inode_sb_list_lock);
	}
}

static unsigned long hash(struct super_block *sb, unsigned long hashval)
{
	unsigned long tmp;

	tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
			L1_CACHE_BYTES;
	tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
	return tmp & i_hash_mask;
}

void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
	struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);

	spin_lock(&inode_hash_lock);
	spin_lock(&inode->i_lock);
	hlist_add_head(&inode->i_hash, b);
	spin_unlock(&inode->i_lock);
	spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);

void __remove_inode_hash(struct inode *inode)
{
	spin_lock(&inode_hash_lock);
	spin_lock(&inode->i_lock);
	hlist_del_init(&inode->i_hash);
	spin_unlock(&inode->i_lock);
	spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__remove_inode_hash);

void end_writeback(struct inode *inode)
{
	might_sleep();
	spin_lock_irq(&inode->i_data.tree_lock);
	BUG_ON(inode->i_data.nrpages);
	spin_unlock_irq(&inode->i_data.tree_lock);
	BUG_ON(!list_empty(&inode->i_data.private_list));
	BUG_ON(!(inode->i_state & I_FREEING));
	BUG_ON(inode->i_state & I_CLEAR);
	inode_sync_wait(inode);
	
	inode->i_state = I_FREEING | I_CLEAR;
}
EXPORT_SYMBOL(end_writeback);

static void evict(struct inode *inode)
{
	const struct super_operations *op = inode->i_sb->s_op;

	BUG_ON(!(inode->i_state & I_FREEING));
	BUG_ON(!list_empty(&inode->i_lru));

	if (!list_empty(&inode->i_wb_list))
		inode_wb_list_del(inode);

	inode_sb_list_del(inode);

	if (op->evict_inode) {
		op->evict_inode(inode);
	} else {
		if (inode->i_data.nrpages)
			truncate_inode_pages(&inode->i_data, 0);
		end_writeback(inode);
	}
	if (S_ISBLK(inode->i_mode) && inode->i_bdev)
		bd_forget(inode);
	if (S_ISCHR(inode->i_mode) && inode->i_cdev)
		cd_forget(inode);

	remove_inode_hash(inode);

	spin_lock(&inode->i_lock);
	wake_up_bit(&inode->i_state, __I_NEW);
	BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
	spin_unlock(&inode->i_lock);

	destroy_inode(inode);
}

static void dispose_list(struct list_head *head)
{
	while (!list_empty(head)) {
		struct inode *inode;

		inode = list_first_entry(head, struct inode, i_lru);
		list_del_init(&inode->i_lru);

		evict(inode);
	}
}

void evict_inodes(struct super_block *sb)
{
	struct inode *inode, *next;
	LIST_HEAD(dispose);

	spin_lock(&inode_sb_list_lock);
	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
		if (atomic_read(&inode->i_count))
			continue;

		spin_lock(&inode->i_lock);
		if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
			spin_unlock(&inode->i_lock);
			continue;
		}

		inode->i_state |= I_FREEING;
		inode_lru_list_del(inode);
		spin_unlock(&inode->i_lock);
		list_add(&inode->i_lru, &dispose);
	}
	spin_unlock(&inode_sb_list_lock);

	dispose_list(&dispose);
}

int invalidate_inodes(struct super_block *sb, bool kill_dirty)
{
	int busy = 0;
	struct inode *inode, *next;
	LIST_HEAD(dispose);

	spin_lock(&inode_sb_list_lock);
	list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
		spin_lock(&inode->i_lock);
		if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (inode->i_state & I_DIRTY && !kill_dirty) {
			spin_unlock(&inode->i_lock);
			busy = 1;
			continue;
		}
		if (atomic_read(&inode->i_count)) {
			spin_unlock(&inode->i_lock);
			busy = 1;
			continue;
		}

		inode->i_state |= I_FREEING;
		inode_lru_list_del(inode);
		spin_unlock(&inode->i_lock);
		list_add(&inode->i_lru, &dispose);
	}
	spin_unlock(&inode_sb_list_lock);

	dispose_list(&dispose);

	return busy;
}

static int can_unuse(struct inode *inode)
{
	if (inode->i_state & ~I_REFERENCED)
		return 0;
	if (inode_has_buffers(inode))
		return 0;
	if (atomic_read(&inode->i_count))
		return 0;
	if (inode->i_data.nrpages)
		return 0;
	return 1;
}

void prune_icache_sb(struct super_block *sb, int nr_to_scan)
{
	LIST_HEAD(freeable);
	int nr_scanned;
	unsigned long reap = 0;

	spin_lock(&sb->s_inode_lru_lock);
	for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) {
		struct inode *inode;

		if (list_empty(&sb->s_inode_lru))
			break;

		inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru);

		if (!spin_trylock(&inode->i_lock)) {
			list_move_tail(&inode->i_lru, &sb->s_inode_lru);
			continue;
		}

		if (atomic_read(&inode->i_count) ||
		    (inode->i_state & ~I_REFERENCED)) {
			list_del_init(&inode->i_lru);
			spin_unlock(&inode->i_lock);
			sb->s_nr_inodes_unused--;
			this_cpu_dec(nr_unused);
			continue;
		}

		
		if (inode->i_state & I_REFERENCED) {
			inode->i_state &= ~I_REFERENCED;
			list_move(&inode->i_lru, &sb->s_inode_lru);
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (inode_has_buffers(inode) || inode->i_data.nrpages) {
			__iget(inode);
			spin_unlock(&inode->i_lock);
			spin_unlock(&sb->s_inode_lru_lock);
			if (remove_inode_buffers(inode))
				reap += invalidate_mapping_pages(&inode->i_data,
								0, -1);
			iput(inode);
			spin_lock(&sb->s_inode_lru_lock);

			if (inode != list_entry(sb->s_inode_lru.next,
						struct inode, i_lru))
				continue;	
			
			if (!spin_trylock(&inode->i_lock))
				continue;
			if (!can_unuse(inode)) {
				spin_unlock(&inode->i_lock);
				continue;
			}
		}
		WARN_ON(inode->i_state & I_NEW);
		inode->i_state |= I_FREEING;
		spin_unlock(&inode->i_lock);

		list_move(&inode->i_lru, &freeable);
		sb->s_nr_inodes_unused--;
		this_cpu_dec(nr_unused);
	}
	if (current_is_kswapd())
		__count_vm_events(KSWAPD_INODESTEAL, reap);
	else
		__count_vm_events(PGINODESTEAL, reap);
	spin_unlock(&sb->s_inode_lru_lock);
	if (current->reclaim_state)
		current->reclaim_state->reclaimed_slab += reap;

	dispose_list(&freeable);
}

static void __wait_on_freeing_inode(struct inode *inode);
static struct inode *find_inode(struct super_block *sb,
				struct hlist_head *head,
				int (*test)(struct inode *, void *),
				void *data)
{
	struct hlist_node *node;
	struct inode *inode = NULL;

repeat:
	hlist_for_each_entry(inode, node, head, i_hash) {
		spin_lock(&inode->i_lock);
		if (inode->i_sb != sb) {
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (!test(inode, data)) {
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		__iget(inode);
		spin_unlock(&inode->i_lock);
		return inode;
	}
	return NULL;
}

static struct inode *find_inode_fast(struct super_block *sb,
				struct hlist_head *head, unsigned long ino)
{
	struct hlist_node *node;
	struct inode *inode = NULL;

repeat:
	hlist_for_each_entry(inode, node, head, i_hash) {
		spin_lock(&inode->i_lock);
		if (inode->i_ino != ino) {
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (inode->i_sb != sb) {
			spin_unlock(&inode->i_lock);
			continue;
		}
		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		__iget(inode);
		spin_unlock(&inode->i_lock);
		return inode;
	}
	return NULL;
}

#define LAST_INO_BATCH 1024
static DEFINE_PER_CPU(unsigned int, last_ino);

unsigned int get_next_ino(void)
{
	unsigned int *p = &get_cpu_var(last_ino);
	unsigned int res = *p;

#ifdef CONFIG_SMP
	if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
		static atomic_t shared_last_ino;
		int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);

		res = next - LAST_INO_BATCH;
	}
#endif

	*p = ++res;
	put_cpu_var(last_ino);
	return res;
}
EXPORT_SYMBOL(get_next_ino);

struct inode *new_inode_pseudo(struct super_block *sb)
{
	struct inode *inode = alloc_inode(sb);

	if (inode) {
		spin_lock(&inode->i_lock);
		inode->i_state = 0;
		spin_unlock(&inode->i_lock);
		INIT_LIST_HEAD(&inode->i_sb_list);
	}
	return inode;
}

struct inode *new_inode(struct super_block *sb)
{
	struct inode *inode;

	spin_lock_prefetch(&inode_sb_list_lock);

	inode = new_inode_pseudo(sb);
	if (inode)
		inode_sb_list_add(inode);
	return inode;
}
EXPORT_SYMBOL(new_inode);

#ifdef CONFIG_DEBUG_LOCK_ALLOC
void lockdep_annotate_inode_mutex_key(struct inode *inode)
{
	if (S_ISDIR(inode->i_mode)) {
		struct file_system_type *type = inode->i_sb->s_type;

		
		if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) {
			mutex_destroy(&inode->i_mutex);
			mutex_init(&inode->i_mutex);
			lockdep_set_class(&inode->i_mutex,
					  &type->i_mutex_dir_key);
		}
	}
}
EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
#endif

void unlock_new_inode(struct inode *inode)
{
	lockdep_annotate_inode_mutex_key(inode);
	spin_lock(&inode->i_lock);
	WARN_ON(!(inode->i_state & I_NEW));
	inode->i_state &= ~I_NEW;
	smp_mb();
	wake_up_bit(&inode->i_state, __I_NEW);
	spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(unlock_new_inode);

struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *),
		int (*set)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
	struct inode *inode;

	spin_lock(&inode_hash_lock);
	inode = find_inode(sb, head, test, data);
	spin_unlock(&inode_hash_lock);

	if (inode) {
		wait_on_inode(inode);
		return inode;
	}

	inode = alloc_inode(sb);
	if (inode) {
		struct inode *old;

		spin_lock(&inode_hash_lock);
		
		old = find_inode(sb, head, test, data);
		if (!old) {
			if (set(inode, data))
				goto set_failed;

			spin_lock(&inode->i_lock);
			inode->i_state = I_NEW;
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode->i_lock);
			inode_sb_list_add(inode);
			spin_unlock(&inode_hash_lock);

			return inode;
		}

		spin_unlock(&inode_hash_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;

set_failed:
	spin_unlock(&inode_hash_lock);
	destroy_inode(inode);
	return NULL;
}
EXPORT_SYMBOL(iget5_locked);

struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);
	struct inode *inode;

	spin_lock(&inode_hash_lock);
	inode = find_inode_fast(sb, head, ino);
	spin_unlock(&inode_hash_lock);
	if (inode) {
		wait_on_inode(inode);
		return inode;
	}

	inode = alloc_inode(sb);
	if (inode) {
		struct inode *old;

		spin_lock(&inode_hash_lock);
		
		old = find_inode_fast(sb, head, ino);
		if (!old) {
			inode->i_ino = ino;
			spin_lock(&inode->i_lock);
			inode->i_state = I_NEW;
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode->i_lock);
			inode_sb_list_add(inode);
			spin_unlock(&inode_hash_lock);

			return inode;
		}

		spin_unlock(&inode_hash_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;
}
EXPORT_SYMBOL(iget_locked);

static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *b = inode_hashtable + hash(sb, ino);
	struct hlist_node *node;
	struct inode *inode;

	spin_lock(&inode_hash_lock);
	hlist_for_each_entry(inode, node, b, i_hash) {
		if (inode->i_ino == ino && inode->i_sb == sb) {
			spin_unlock(&inode_hash_lock);
			return 0;
		}
	}
	spin_unlock(&inode_hash_lock);

	return 1;
}

ino_t iunique(struct super_block *sb, ino_t max_reserved)
{
	static DEFINE_SPINLOCK(iunique_lock);
	static unsigned int counter;
	ino_t res;

	spin_lock(&iunique_lock);
	do {
		if (counter <= max_reserved)
			counter = max_reserved + 1;
		res = counter++;
	} while (!test_inode_iunique(sb, res));
	spin_unlock(&iunique_lock);

	return res;
}
EXPORT_SYMBOL(iunique);

struct inode *igrab(struct inode *inode)
{
	spin_lock(&inode->i_lock);
	if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
		__iget(inode);
		spin_unlock(&inode->i_lock);
	} else {
		spin_unlock(&inode->i_lock);
		inode = NULL;
	}
	return inode;
}
EXPORT_SYMBOL(igrab);

struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
	struct inode *inode;

	spin_lock(&inode_hash_lock);
	inode = find_inode(sb, head, test, data);
	spin_unlock(&inode_hash_lock);

	return inode;
}
EXPORT_SYMBOL(ilookup5_nowait);

struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct inode *inode = ilookup5_nowait(sb, hashval, test, data);

	if (inode)
		wait_on_inode(inode);
	return inode;
}
EXPORT_SYMBOL(ilookup5);

struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);
	struct inode *inode;

	spin_lock(&inode_hash_lock);
	inode = find_inode_fast(sb, head, ino);
	spin_unlock(&inode_hash_lock);

	if (inode)
		wait_on_inode(inode);
	return inode;
}
EXPORT_SYMBOL(ilookup);

int insert_inode_locked(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	ino_t ino = inode->i_ino;
	struct hlist_head *head = inode_hashtable + hash(sb, ino);

	while (1) {
		struct hlist_node *node;
		struct inode *old = NULL;
		spin_lock(&inode_hash_lock);
		hlist_for_each_entry(old, node, head, i_hash) {
			if (old->i_ino != ino)
				continue;
			if (old->i_sb != sb)
				continue;
			spin_lock(&old->i_lock);
			if (old->i_state & (I_FREEING|I_WILL_FREE)) {
				spin_unlock(&old->i_lock);
				continue;
			}
			break;
		}
		if (likely(!node)) {
			spin_lock(&inode->i_lock);
			inode->i_state |= I_NEW;
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode->i_lock);
			spin_unlock(&inode_hash_lock);
			return 0;
		}
		__iget(old);
		spin_unlock(&old->i_lock);
		spin_unlock(&inode_hash_lock);
		wait_on_inode(old);
		if (unlikely(!inode_unhashed(old))) {
			iput(old);
			return -EBUSY;
		}
		iput(old);
	}
}
EXPORT_SYMBOL(insert_inode_locked);

int insert_inode_locked4(struct inode *inode, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct super_block *sb = inode->i_sb;
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);

	while (1) {
		struct hlist_node *node;
		struct inode *old = NULL;

		spin_lock(&inode_hash_lock);
		hlist_for_each_entry(old, node, head, i_hash) {
			if (old->i_sb != sb)
				continue;
			if (!test(old, data))
				continue;
			spin_lock(&old->i_lock);
			if (old->i_state & (I_FREEING|I_WILL_FREE)) {
				spin_unlock(&old->i_lock);
				continue;
			}
			break;
		}
		if (likely(!node)) {
			spin_lock(&inode->i_lock);
			inode->i_state |= I_NEW;
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode->i_lock);
			spin_unlock(&inode_hash_lock);
			return 0;
		}
		__iget(old);
		spin_unlock(&old->i_lock);
		spin_unlock(&inode_hash_lock);
		wait_on_inode(old);
		if (unlikely(!inode_unhashed(old))) {
			iput(old);
			return -EBUSY;
		}
		iput(old);
	}
}
EXPORT_SYMBOL(insert_inode_locked4);


int generic_delete_inode(struct inode *inode)
{
	return 1;
}
EXPORT_SYMBOL(generic_delete_inode);

static void iput_final(struct inode *inode)
{
	struct super_block *sb = inode->i_sb;
	const struct super_operations *op = inode->i_sb->s_op;
	int drop;

	WARN_ON(inode->i_state & I_NEW);

	if (op->drop_inode)
		drop = op->drop_inode(inode);
	else
		drop = generic_drop_inode(inode);

	if (!drop && (sb->s_flags & MS_ACTIVE)) {
		inode->i_state |= I_REFERENCED;
		if (!(inode->i_state & (I_DIRTY|I_SYNC)))
			inode_lru_list_add(inode);
		spin_unlock(&inode->i_lock);
		return;
	}

	if (!drop) {
		inode->i_state |= I_WILL_FREE;
		spin_unlock(&inode->i_lock);
		write_inode_now(inode, 1);
		spin_lock(&inode->i_lock);
		WARN_ON(inode->i_state & I_NEW);
		inode->i_state &= ~I_WILL_FREE;
	}

	inode->i_state |= I_FREEING;
	if (!list_empty(&inode->i_lru))
		inode_lru_list_del(inode);
	spin_unlock(&inode->i_lock);

	evict(inode);
}

void iput(struct inode *inode)
{
	if (inode) {
		BUG_ON(inode->i_state & I_CLEAR);

		if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
			iput_final(inode);
	}
}
EXPORT_SYMBOL(iput);

sector_t bmap(struct inode *inode, sector_t block)
{
	sector_t res = 0;
	if (inode->i_mapping->a_ops->bmap)
		res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
	return res;
}
EXPORT_SYMBOL(bmap);

static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
			     struct timespec now)
{

	if (!(mnt->mnt_flags & MNT_RELATIME))
		return 1;
	if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
		return 1;
	if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
		return 1;

	if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
		return 1;
	return 0;
}

void touch_atime(struct path *path)
{
	struct vfsmount *mnt = path->mnt;
	struct inode *inode = path->dentry->d_inode;
	struct timespec now;

	if (inode->i_flags & S_NOATIME)
		return;
	if (IS_NOATIME(inode))
		return;
	if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
		return;

	if (mnt->mnt_flags & MNT_NOATIME)
		return;
	if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
		return;

	now = current_fs_time(inode->i_sb);

	if (!relatime_need_update(mnt, inode, now))
		return;

	if (timespec_equal(&inode->i_atime, &now))
		return;

	if (mnt_want_write(mnt))
		return;

	inode->i_atime = now;
	mark_inode_dirty_sync(inode);
	mnt_drop_write(mnt);
}
EXPORT_SYMBOL(touch_atime);


void file_update_time(struct file *file)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct timespec now;
	enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;

	
	if (IS_NOCMTIME(inode))
		return;

	now = current_fs_time(inode->i_sb);
	if (!timespec_equal(&inode->i_mtime, &now))
		sync_it = S_MTIME;

	if (!timespec_equal(&inode->i_ctime, &now))
		sync_it |= S_CTIME;

	if (IS_I_VERSION(inode))
		sync_it |= S_VERSION;

	if (!sync_it)
		return;

	
	if (mnt_want_write_file(file))
		return;

	
	if (sync_it & S_VERSION)
		inode_inc_iversion(inode);
	if (sync_it & S_CTIME)
		inode->i_ctime = now;
	if (sync_it & S_MTIME)
		inode->i_mtime = now;
	mark_inode_dirty_sync(inode);
	mnt_drop_write_file(file);
}
EXPORT_SYMBOL(file_update_time);

int inode_needs_sync(struct inode *inode)
{
	if (IS_SYNC(inode))
		return 1;
	if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
		return 1;
	return 0;
}
EXPORT_SYMBOL(inode_needs_sync);

int inode_wait(void *word)
{
	schedule();
	return 0;
}
EXPORT_SYMBOL(inode_wait);

static void __wait_on_freeing_inode(struct inode *inode)
{
	wait_queue_head_t *wq;
	DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
	wq = bit_waitqueue(&inode->i_state, __I_NEW);
	prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
	spin_unlock(&inode->i_lock);
	spin_unlock(&inode_hash_lock);
	schedule();
	finish_wait(wq, &wait.wait);
	spin_lock(&inode_hash_lock);
}

static __initdata unsigned long ihash_entries;
static int __init set_ihash_entries(char *str)
{
	if (!str)
		return 0;
	ihash_entries = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("ihash_entries=", set_ihash_entries);

void __init inode_init_early(void)
{
	unsigned int loop;

	if (hashdist)
		return;

	inode_hashtable =
		alloc_large_system_hash("Inode-cache",
					sizeof(struct hlist_head),
					ihash_entries,
					14,
					HASH_EARLY,
					&i_hash_shift,
					&i_hash_mask,
					0);

	for (loop = 0; loop < (1U << i_hash_shift); loop++)
		INIT_HLIST_HEAD(&inode_hashtable[loop]);
}

void __init inode_init(void)
{
	unsigned int loop;

	
	inode_cachep = kmem_cache_create("inode_cache",
					 sizeof(struct inode),
					 0,
					 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
					 SLAB_MEM_SPREAD),
					 init_once);

	
	if (!hashdist)
		return;

	inode_hashtable =
		alloc_large_system_hash("Inode-cache",
					sizeof(struct hlist_head),
					ihash_entries,
					14,
					0,
					&i_hash_shift,
					&i_hash_mask,
					0);

	for (loop = 0; loop < (1U << i_hash_shift); loop++)
		INIT_HLIST_HEAD(&inode_hashtable[loop]);
}

void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
{
	inode->i_mode = mode;
	if (S_ISCHR(mode)) {
		inode->i_fop = &def_chr_fops;
		inode->i_rdev = rdev;
	} else if (S_ISBLK(mode)) {
		inode->i_fop = &def_blk_fops;
		inode->i_rdev = rdev;
	} else if (S_ISFIFO(mode))
		inode->i_fop = &def_fifo_fops;
	else if (S_ISSOCK(mode))
		inode->i_fop = &bad_sock_fops;
	else
		printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
				  " inode %s:%lu\n", mode, inode->i_sb->s_id,
				  inode->i_ino);
}
EXPORT_SYMBOL(init_special_inode);

void inode_init_owner(struct inode *inode, const struct inode *dir,
			umode_t mode)
{
	inode->i_uid = current_fsuid();
	if (dir && dir->i_mode & S_ISGID) {
		inode->i_gid = dir->i_gid;
		if (S_ISDIR(mode))
			mode |= S_ISGID;
	} else
		inode->i_gid = current_fsgid();
	inode->i_mode = mode;
}
EXPORT_SYMBOL(inode_init_owner);

bool inode_owner_or_capable(const struct inode *inode)
{
	struct user_namespace *ns = inode_userns(inode);

	if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
		return true;
	if (ns_capable(ns, CAP_FOWNER))
		return true;
	if (current_user_ns() == ns &&
		(inode->i_gid == AID_SDCARD_RW || inode->i_gid == AID_SDCARD_R))
		return true;
	return false;
}
EXPORT_SYMBOL(inode_owner_or_capable);