inode.c 42.3 KB
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/*
 * linux/fs/inode.c
 *
 * (C) 1997 Linus Torvalds
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/dcache.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/writeback.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
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#include <linux/rwsem.h>
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#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/pagemap.h>
#include <linux/cdev.h>
#include <linux/bootmem.h>
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#include <linux/inotify.h>
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#include <linux/fsnotify.h>
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#include <linux/mount.h>
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#include <linux/async.h>
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#include <linux/posix_acl.h>
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/*
 * This is needed for the following functions:
 *  - inode_has_buffers
 *  - invalidate_inode_buffers
 *  - invalidate_bdev
 *
 * FIXME: remove all knowledge of the buffer layer from this file
 */
#include <linux/buffer_head.h>

/*
 * New inode.c implementation.
 *
 * This implementation has the basic premise of trying
 * to be extremely low-overhead and SMP-safe, yet be
 * simple enough to be "obviously correct".
 *
 * Famous last words.
 */

/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */

/* #define INODE_PARANOIA 1 */
/* #define INODE_DEBUG 1 */

/*
 * Inode lookup is no longer as critical as it used to be:
 * most of the lookups are going to be through the dcache.
 */
#define I_HASHBITS	i_hash_shift
#define I_HASHMASK	i_hash_mask

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static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
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/*
 * Each inode can be on two separate lists. One is
 * the hash list of the inode, used for lookups. The
 * other linked list is the "type" list:
 *  "in_use" - valid inode, i_count > 0, i_nlink > 0
 *  "dirty"  - as "in_use" but also dirty
 *  "unused" - valid inode, i_count = 0
 *
 * A "dirty" list is maintained for each super block,
 * allowing for low-overhead inode sync() operations.
 */

LIST_HEAD(inode_in_use);
LIST_HEAD(inode_unused);
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static struct hlist_head *inode_hashtable __read_mostly;
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/*
 * A simple spinlock to protect the list manipulations.
 *
 * NOTE! You also have to own the lock if you change
 * the i_state of an inode while it is in use..
 */
DEFINE_SPINLOCK(inode_lock);

/*
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 * iprune_sem provides exclusion between the kswapd or try_to_free_pages
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 * icache shrinking path, and the umount path.  Without this exclusion,
 * by the time prune_icache calls iput for the inode whose pages it has
 * been invalidating, or by the time it calls clear_inode & destroy_inode
 * from its final dispose_list, the struct super_block they refer to
 * (for inode->i_sb->s_op) may already have been freed and reused.
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 *
 * We make this an rwsem because the fastpath is icache shrinking. In
 * some cases a filesystem may be doing a significant amount of work in
 * its inode reclaim code, so this should improve parallelism.
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 */
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static DECLARE_RWSEM(iprune_sem);
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/*
 * Statistics gathering..
 */
struct inodes_stat_t inodes_stat;

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static struct kmem_cache *inode_cachep __read_mostly;
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static void wake_up_inode(struct inode *inode)
{
	/*
	 * Prevent speculative execution through spin_unlock(&inode_lock);
	 */
	smp_mb();
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	wake_up_bit(&inode->i_state, __I_NEW);
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}

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/**
 * inode_init_always - perform inode structure intialisation
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 * @sb: superblock inode belongs to
 * @inode: inode to initialise
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 *
 * These are initializations that need to be done on every inode
 * allocation as the fields are not initialised by slab allocation.
 */
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int inode_init_always(struct super_block *sb, struct inode *inode)
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{
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	static const struct address_space_operations empty_aops;
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	static const struct inode_operations empty_iops;
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	static const struct file_operations empty_fops;
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	struct address_space *const mapping = &inode->i_data;
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	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;
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	inode->i_uid = 0;
	inode->i_gid = 0;
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	atomic_set(&inode->i_writecount, 0);
	inode->i_size = 0;
	inode->i_blocks = 0;
	inode->i_bytes = 0;
	inode->i_generation = 0;
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#ifdef CONFIG_QUOTA
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	memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
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#endif
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	inode->i_pipe = NULL;
	inode->i_bdev = NULL;
	inode->i_cdev = NULL;
	inode->i_rdev = 0;
	inode->dirtied_when = 0;
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	if (security_inode_alloc(inode))
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		goto out;
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	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);

	init_rwsem(&inode->i_alloc_sem);
	lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);

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

	/*
	 * If the block_device provides a backing_dev_info for client
	 * inodes then use that.  Otherwise the inode share the bdev's
	 * backing_dev_info.
	 */
	if (sb->s_bdev) {
		struct backing_dev_info *bdi;

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		bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
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		mapping->backing_dev_info = bdi;
	}
	inode->i_private = NULL;
	inode->i_mapping = mapping;
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#ifdef CONFIG_FS_POSIX_ACL
	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
#endif
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#ifdef CONFIG_FSNOTIFY
	inode->i_fsnotify_mask = 0;
#endif

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	return 0;
out:
	return -ENOMEM;
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}
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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);

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	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;
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}
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void __destroy_inode(struct inode *inode)
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{
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	BUG_ON(inode_has_buffers(inode));
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	security_inode_free(inode);
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	fsnotify_inode_delete(inode);
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#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
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}
EXPORT_SYMBOL(__destroy_inode);

void destroy_inode(struct inode *inode)
{
	__destroy_inode(inode);
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	if (inode->i_sb->s_op->destroy_inode)
		inode->i_sb->s_op->destroy_inode(inode);
	else
		kmem_cache_free(inode_cachep, (inode));
}

/*
 * These are initializations that only need to be done
 * once, because the fields are idempotent across use
 * of the inode, so let the slab aware of that.
 */
void inode_init_once(struct inode *inode)
{
	memset(inode, 0, sizeof(*inode));
	INIT_HLIST_NODE(&inode->i_hash);
	INIT_LIST_HEAD(&inode->i_dentry);
	INIT_LIST_HEAD(&inode->i_devices);
	INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
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	spin_lock_init(&inode->i_data.tree_lock);
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	spin_lock_init(&inode->i_data.i_mmap_lock);
	INIT_LIST_HEAD(&inode->i_data.private_list);
	spin_lock_init(&inode->i_data.private_lock);
	INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
	INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
	i_size_ordered_init(inode);
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#ifdef CONFIG_INOTIFY
	INIT_LIST_HEAD(&inode->inotify_watches);
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	mutex_init(&inode->inotify_mutex);
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#endif
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#ifdef CONFIG_FSNOTIFY
	INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries);
#endif
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}
EXPORT_SYMBOL(inode_init_once);

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

/*
 * inode_lock must be held
 */
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void __iget(struct inode *inode)
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{
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	if (atomic_inc_return(&inode->i_count) != 1)
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		return;
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	if (!(inode->i_state & (I_DIRTY|I_SYNC)))
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		list_move(&inode->i_list, &inode_in_use);
	inodes_stat.nr_unused--;
}

/**
 * clear_inode - clear an inode
 * @inode: inode to clear
 *
 * This is called by the filesystem to tell us
 * that the inode is no longer useful. We just
 * terminate it with extreme prejudice.
 */
void clear_inode(struct inode *inode)
{
	might_sleep();
	invalidate_inode_buffers(inode);
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	BUG_ON(inode->i_data.nrpages);
	BUG_ON(!(inode->i_state & I_FREEING));
	BUG_ON(inode->i_state & I_CLEAR);
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	inode_sync_wait(inode);
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	if (inode->i_sb->s_op->clear_inode)
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		inode->i_sb->s_op->clear_inode(inode);
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	inode->i_state = I_FREEING | I_CLEAR;
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}
EXPORT_SYMBOL(clear_inode);

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

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

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/*
 * dispose_list - dispose of the contents of a local list
 * @head: the head of the list to free
 *
 * Dispose-list gets a local list with local inodes in it, so it doesn't
 * need to worry about list corruption and SMP locks.
 */
static void dispose_list(struct list_head *head)
{
	int nr_disposed = 0;

	while (!list_empty(head)) {
		struct inode *inode;

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		inode = list_first_entry(head, struct inode, i_list);
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		list_del(&inode->i_list);

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		evict(inode, 0);
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		spin_lock(&inode_lock);
		hlist_del_init(&inode->i_hash);
		list_del_init(&inode->i_sb_list);
		spin_unlock(&inode_lock);

		wake_up_inode(inode);
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		destroy_inode(inode);
		nr_disposed++;
	}
	spin_lock(&inode_lock);
	inodes_stat.nr_inodes -= nr_disposed;
	spin_unlock(&inode_lock);
}

/*
 * Invalidate all inodes for a device.
 */
static int invalidate_list(struct list_head *head, struct list_head *dispose)
{
	struct list_head *next;
	int busy = 0, count = 0;

	next = head->next;
	for (;;) {
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		struct list_head *tmp = next;
		struct inode *inode;
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		/*
		 * We can reschedule here without worrying about the list's
		 * consistency because the per-sb list of inodes must not
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		 * change during umount anymore, and because iprune_sem keeps
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		 * shrink_icache_memory() away.
		 */
		cond_resched_lock(&inode_lock);

		next = next->next;
		if (tmp == head)
			break;
		inode = list_entry(tmp, struct inode, i_sb_list);
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		if (inode->i_state & I_NEW)
			continue;
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		invalidate_inode_buffers(inode);
		if (!atomic_read(&inode->i_count)) {
			list_move(&inode->i_list, dispose);
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			WARN_ON(inode->i_state & I_NEW);
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			inode->i_state |= I_FREEING;
			count++;
			continue;
		}
		busy = 1;
	}
	/* only unused inodes may be cached with i_count zero */
	inodes_stat.nr_unused -= count;
	return busy;
}

/**
 *	invalidate_inodes	- discard the inodes on a device
 *	@sb: superblock
 *
 *	Discard all of the inodes for a given superblock. If the discard
 *	fails because there are busy inodes then a non zero value is returned.
 *	If the discard is successful all the inodes have been discarded.
 */
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int invalidate_inodes(struct super_block *sb)
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{
	int busy;
	LIST_HEAD(throw_away);

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	down_write(&iprune_sem);
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	spin_lock(&inode_lock);
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	inotify_unmount_inodes(&sb->s_inodes);
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	fsnotify_unmount_inodes(&sb->s_inodes);
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	busy = invalidate_list(&sb->s_inodes, &throw_away);
	spin_unlock(&inode_lock);

	dispose_list(&throw_away);
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	up_write(&iprune_sem);
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	return busy;
}
EXPORT_SYMBOL(invalidate_inodes);

static int can_unuse(struct inode *inode)
{
	if (inode->i_state)
		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;
}

/*
 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
 * a temporary list and then are freed outside inode_lock by dispose_list().
 *
 * Any inodes which are pinned purely because of attached pagecache have their
 * pagecache removed.  We expect the final iput() on that inode to add it to
 * the front of the inode_unused list.  So look for it there and if the
 * inode is still freeable, proceed.  The right inode is found 99.9% of the
 * time in testing on a 4-way.
 *
 * If the inode has metadata buffers attached to mapping->private_list then
 * try to remove them.
 */
static void prune_icache(int nr_to_scan)
{
	LIST_HEAD(freeable);
	int nr_pruned = 0;
	int nr_scanned;
	unsigned long reap = 0;

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	down_read(&iprune_sem);
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	spin_lock(&inode_lock);
	for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
		struct inode *inode;

		if (list_empty(&inode_unused))
			break;

		inode = list_entry(inode_unused.prev, struct inode, i_list);

		if (inode->i_state || atomic_read(&inode->i_count)) {
			list_move(&inode->i_list, &inode_unused);
			continue;
		}
		if (inode_has_buffers(inode) || inode->i_data.nrpages) {
			__iget(inode);
			spin_unlock(&inode_lock);
			if (remove_inode_buffers(inode))
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				reap += invalidate_mapping_pages(&inode->i_data,
								0, -1);
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			iput(inode);
			spin_lock(&inode_lock);

			if (inode != list_entry(inode_unused.next,
						struct inode, i_list))
				continue;	/* wrong inode or list_empty */
			if (!can_unuse(inode))
				continue;
		}
		list_move(&inode->i_list, &freeable);
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		WARN_ON(inode->i_state & I_NEW);
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		inode->i_state |= I_FREEING;
		nr_pruned++;
	}
	inodes_stat.nr_unused -= nr_pruned;
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	if (current_is_kswapd())
		__count_vm_events(KSWAPD_INODESTEAL, reap);
	else
		__count_vm_events(PGINODESTEAL, reap);
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	spin_unlock(&inode_lock);

	dispose_list(&freeable);
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	up_read(&iprune_sem);
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}

/*
 * shrink_icache_memory() will attempt to reclaim some unused inodes.  Here,
 * "unused" means that no dentries are referring to the inodes: the files are
 * not open and the dcache references to those inodes have already been
 * reclaimed.
 *
 * This function is passed the number of inodes to scan, and it returns the
 * total number of remaining possibly-reclaimable inodes.
 */
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static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
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{
	if (nr) {
		/*
		 * Nasty deadlock avoidance.  We may hold various FS locks,
		 * and we don't want to recurse into the FS that called us
		 * in clear_inode() and friends..
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		 */
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		if (!(gfp_mask & __GFP_FS))
			return -1;
		prune_icache(nr);
	}
	return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}

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static struct shrinker icache_shrinker = {
	.shrink = shrink_icache_memory,
	.seeks = DEFAULT_SEEKS,
};

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static void __wait_on_freeing_inode(struct inode *inode);
/*
 * Called with the inode lock held.
 * NOTE: we are not increasing the inode-refcount, you must call __iget()
 * by hand after calling find_inode now! This simplifies iunique and won't
 * add any additional branch in the common code.
 */
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static struct inode *find_inode(struct super_block *sb,
				struct hlist_head *head,
				int (*test)(struct inode *, void *),
				void *data)
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{
	struct hlist_node *node;
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	struct inode *inode = NULL;
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repeat:
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	hlist_for_each_entry(inode, node, head, i_hash) {
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		if (inode->i_sb != sb)
			continue;
		if (!test(inode, data))
			continue;
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		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
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			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		break;
	}
	return node ? inode : NULL;
}

/*
 * find_inode_fast is the fast path version of find_inode, see the comment at
 * iget_locked for details.
 */
582 583
static struct inode *find_inode_fast(struct super_block *sb,
				struct hlist_head *head, unsigned long ino)
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{
	struct hlist_node *node;
586
	struct inode *inode = NULL;
L
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587 588

repeat:
589
	hlist_for_each_entry(inode, node, head, i_hash) {
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		if (inode->i_ino != ino)
			continue;
		if (inode->i_sb != sb)
			continue;
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		if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
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			__wait_on_freeing_inode(inode);
			goto repeat;
		}
		break;
	}
	return node ? inode : NULL;
}

603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625
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_HASHBITS);
	return tmp & I_HASHMASK;
}

static inline void
__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
			struct inode *inode)
{
	inodes_stat.nr_inodes++;
	list_add(&inode->i_list, &inode_in_use);
	list_add(&inode->i_sb_list, &sb->s_inodes);
	if (head)
		hlist_add_head(&inode->i_hash, head);
}

/**
 * inode_add_to_lists - add a new inode to relevant lists
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 * @sb: superblock inode belongs to
 * @inode: inode to mark in use
628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
 *
 * When an inode is allocated it needs to be accounted for, added to the in use
 * list, the owning superblock and the inode hash. This needs to be done under
 * the inode_lock, so export a function to do this rather than the inode lock
 * itself. We calculate the hash list to add to here so it is all internal
 * which requires the caller to have already set up the inode number in the
 * inode to add.
 */
void inode_add_to_lists(struct super_block *sb, struct inode *inode)
{
	struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);

	spin_lock(&inode_lock);
	__inode_add_to_lists(sb, head, inode);
	spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(inode_add_to_lists);

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/**
 *	new_inode 	- obtain an inode
 *	@sb: superblock
 *
650
 *	Allocates a new inode for given superblock. The default gfp_mask
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Hugh Dickins 已提交
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 *	for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
652 653 654 655 656
 *	If HIGHMEM pages are unsuitable or it is known that pages allocated
 *	for the page cache are not reclaimable or migratable,
 *	mapping_set_gfp_mask() must be called with suitable flags on the
 *	newly created inode's mapping
 *
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 */
struct inode *new_inode(struct super_block *sb)
{
660 661 662 663 664 665
	/*
	 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
	 * error if st_ino won't fit in target struct field. Use 32bit counter
	 * here to attempt to avoid that.
	 */
	static unsigned int last_ino;
666
	struct inode *inode;
L
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	spin_lock_prefetch(&inode_lock);
669

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	inode = alloc_inode(sb);
	if (inode) {
		spin_lock(&inode_lock);
673
		__inode_add_to_lists(sb, NULL, inode);
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		inode->i_ino = ++last_ino;
		inode->i_state = 0;
		spin_unlock(&inode_lock);
	}
	return inode;
}
EXPORT_SYMBOL(new_inode);

void unlock_new_inode(struct inode *inode)
{
684
#ifdef CONFIG_DEBUG_LOCK_ALLOC
685 686 687
	if (inode->i_mode & S_IFDIR) {
		struct file_system_type *type = inode->i_sb->s_type;

688 689 690 691 692 693 694 695 696 697 698
		/* Set new key only if filesystem hasn't already changed it */
		if (!lockdep_match_class(&inode->i_mutex,
		    &type->i_mutex_key)) {
			/*
			 * ensure nobody is actually holding i_mutex
			 */
			mutex_destroy(&inode->i_mutex);
			mutex_init(&inode->i_mutex);
			lockdep_set_class(&inode->i_mutex,
					  &type->i_mutex_dir_key);
		}
699
	}
700
#endif
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	/*
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Christoph Hellwig 已提交
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	 * This is special!  We do not need the spinlock when clearing I_NEW,
703 704
	 * because we're guaranteed that nobody else tries to do anything about
	 * the state of the inode when it is locked, as we just created it (so
C
Christoph Hellwig 已提交
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	 * there can be no old holders that haven't tested I_NEW).
706
	 * However we must emit the memory barrier so that other CPUs reliably
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Christoph Hellwig 已提交
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	 * see the clearing of I_NEW after the other inode initialisation has
708
	 * completed.
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	 */
710
	smp_mb();
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	WARN_ON(!(inode->i_state & I_NEW));
	inode->i_state &= ~I_NEW;
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	wake_up_inode(inode);
}
EXPORT_SYMBOL(unlock_new_inode);

/*
 * This is called without the inode lock held.. Be careful.
 *
 * We no longer cache the sb_flags in i_flags - see fs.h
 *	-- rmk@arm.uk.linux.org
 */
723 724 725 726 727
static struct inode *get_new_inode(struct super_block *sb,
				struct hlist_head *head,
				int (*test)(struct inode *, void *),
				int (*set)(struct inode *, void *),
				void *data)
L
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{
729
	struct inode *inode;
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	inode = alloc_inode(sb);
	if (inode) {
733
		struct inode *old;
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734 735 736 737 738 739 740 741

		spin_lock(&inode_lock);
		/* We released the lock, so.. */
		old = find_inode(sb, head, test, data);
		if (!old) {
			if (set(inode, data))
				goto set_failed;

742
			__inode_add_to_lists(sb, head, inode);
C
Christoph Hellwig 已提交
743
			inode->i_state = I_NEW;
L
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			spin_unlock(&inode_lock);

			/* Return the locked inode with I_NEW set, the
			 * caller is responsible for filling in the contents
			 */
			return inode;
		}

		/*
		 * Uhhuh, somebody else created the same inode under
		 * us. Use the old inode instead of the one we just
		 * allocated.
		 */
		__iget(old);
		spin_unlock(&inode_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;

set_failed:
	spin_unlock(&inode_lock);
	destroy_inode(inode);
	return NULL;
}

/*
 * get_new_inode_fast is the fast path version of get_new_inode, see the
 * comment at iget_locked for details.
 */
775 776
static struct inode *get_new_inode_fast(struct super_block *sb,
				struct hlist_head *head, unsigned long ino)
L
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{
778
	struct inode *inode;
L
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779 780 781

	inode = alloc_inode(sb);
	if (inode) {
782
		struct inode *old;
L
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783 784 785 786 787 788

		spin_lock(&inode_lock);
		/* We released the lock, so.. */
		old = find_inode_fast(sb, head, ino);
		if (!old) {
			inode->i_ino = ino;
789
			__inode_add_to_lists(sb, head, inode);
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Christoph Hellwig 已提交
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			inode->i_state = I_NEW;
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			spin_unlock(&inode_lock);

			/* Return the locked inode with I_NEW set, the
			 * caller is responsible for filling in the contents
			 */
			return inode;
		}

		/*
		 * Uhhuh, somebody else created the same inode under
		 * us. Use the old inode instead of the one we just
		 * allocated.
		 */
		__iget(old);
		spin_unlock(&inode_lock);
		destroy_inode(inode);
		inode = old;
		wait_on_inode(inode);
	}
	return inode;
}

/**
 *	iunique - get a unique inode number
 *	@sb: superblock
 *	@max_reserved: highest reserved inode number
 *
 *	Obtain an inode number that is unique on the system for a given
 *	superblock. This is used by file systems that have no natural
 *	permanent inode numbering system. An inode number is returned that
 *	is higher than the reserved limit but unique.
 *
 *	BUGS:
 *	With a large number of inodes live on the file system this function
 *	currently becomes quite slow.
 */
ino_t iunique(struct super_block *sb, ino_t max_reserved)
{
829 830 831 832 833 834
	/*
	 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
	 * error if st_ino won't fit in target struct field. Use 32bit counter
	 * here to attempt to avoid that.
	 */
	static unsigned int counter;
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	struct inode *inode;
836
	struct hlist_head *head;
L
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837
	ino_t res;
838

L
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	spin_lock(&inode_lock);
840 841 842
	do {
		if (counter <= max_reserved)
			counter = max_reserved + 1;
L
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		res = counter++;
844
		head = inode_hashtable + hash(sb, res);
L
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		inode = find_inode_fast(sb, head, res);
846 847
	} while (inode != NULL);
	spin_unlock(&inode_lock);
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849 850
	return res;
}
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EXPORT_SYMBOL(iunique);

struct inode *igrab(struct inode *inode)
{
	spin_lock(&inode_lock);
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Al Viro 已提交
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	if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
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		__iget(inode);
	else
		/*
		 * Handle the case where s_op->clear_inode is not been
		 * called yet, and somebody is calling igrab
		 * while the inode is getting freed.
		 */
		inode = NULL;
	spin_unlock(&inode_lock);
	return inode;
}
EXPORT_SYMBOL(igrab);

/**
 * ifind - internal function, you want ilookup5() or iget5().
 * @sb:		super block of file system to search
 * @head:       the head of the list to search
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
876
 * @wait:	if true wait for the inode to be unlocked, if false do not
L
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 *
 * ifind() searches for the inode specified by @data in the inode
 * cache. This is a generalized version of ifind_fast() for file systems where
 * the inode number is not sufficient for unique identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
889
static struct inode *ifind(struct super_block *sb,
L
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890
		struct hlist_head *head, int (*test)(struct inode *, void *),
891
		void *data, const int wait)
L
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{
	struct inode *inode;

	spin_lock(&inode_lock);
	inode = find_inode(sb, head, test, data);
	if (inode) {
		__iget(inode);
		spin_unlock(&inode_lock);
900 901
		if (likely(wait))
			wait_on_inode(inode);
L
Linus Torvalds 已提交
902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922
		return inode;
	}
	spin_unlock(&inode_lock);
	return NULL;
}

/**
 * ifind_fast - internal function, you want ilookup() or iget().
 * @sb:		super block of file system to search
 * @head:       head of the list to search
 * @ino:	inode number to search for
 *
 * ifind_fast() searches for the inode @ino in the inode cache. This is for
 * file systems where the inode number is sufficient for unique identification
 * of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 */
923
static struct inode *ifind_fast(struct super_block *sb,
L
Linus Torvalds 已提交
924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940
		struct hlist_head *head, unsigned long ino)
{
	struct inode *inode;

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

/**
941
 * ilookup5_nowait - search for an inode in the inode cache
L
Linus Torvalds 已提交
942 943 944 945 946 947 948 949 950 951 952
 * @sb:		super block of file system to search
 * @hashval:	hash value (usually inode number) to search for
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
 *
 * ilookup5() uses ifind() to search for the inode specified by @hashval and
 * @data in the inode cache. This is a generalized version of ilookup() for
 * file systems where the inode number is not sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983
 * reference count.  Note, the inode lock is not waited upon so you have to be
 * very careful what you do with the returned inode.  You probably should be
 * using ilookup5() instead.
 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
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);

	return ifind(sb, head, test, data, 0);
}
EXPORT_SYMBOL(ilookup5_nowait);

/**
 * ilookup5 - search for an inode in the inode cache
 * @sb:		super block of file system to search
 * @hashval:	hash value (usually inode number) to search for
 * @test:	callback used for comparisons between inodes
 * @data:	opaque data pointer to pass to @test
 *
 * ilookup5() uses ifind() to search for the inode specified by @hashval and
 * @data in the inode cache. This is a generalized version of ilookup() for
 * file systems where the inode number is not sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode lock is waited upon and the inode is
 * returned with an incremented reference count.
L
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 *
 * Otherwise NULL is returned.
 *
 * Note, @test is called with the inode_lock held, so can't sleep.
 */
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
		int (*test)(struct inode *, void *), void *data)
{
	struct hlist_head *head = inode_hashtable + hash(sb, hashval);

994
	return ifind(sb, head, test, data, 1);
L
Linus Torvalds 已提交
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
}
EXPORT_SYMBOL(ilookup5);

/**
 * ilookup - search for an inode in the inode cache
 * @sb:		super block of file system to search
 * @ino:	inode number to search for
 *
 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
 * This is for file systems where the inode number is sufficient for unique
 * identification of an inode.
 *
 * If the inode is in the cache, the inode is returned with an incremented
 * reference count.
 *
 * Otherwise NULL is returned.
 */
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);

	return ifind_fast(sb, head, ino);
}
EXPORT_SYMBOL(ilookup);

/**
 * iget5_locked - obtain an inode from a mounted file system
 * @sb:		super block of file system
 * @hashval:	hash value (usually inode number) to get
 * @test:	callback used for comparisons between inodes
 * @set:	callback used to initialize a new struct inode
 * @data:	opaque data pointer to pass to @test and @set
 *
 * iget5_locked() uses ifind() to search for the inode specified by @hashval
 * and @data in the inode cache and if present it is returned with an increased
 * reference count. This is a generalized version of iget_locked() for file
 * systems where the inode number is not sufficient for unique identification
 * of an inode.
 *
 * If the inode is not in cache, get_new_inode() is called to allocate a new
 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
 * file system gets to fill it in before unlocking it via unlock_new_inode().
 *
 * Note both @test and @set are called with the inode_lock held, so can't sleep.
 */
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;

1047
	inode = ifind(sb, head, test, data, 1);
L
Linus Torvalds 已提交
1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088
	if (inode)
		return inode;
	/*
	 * get_new_inode() will do the right thing, re-trying the search
	 * in case it had to block at any point.
	 */
	return get_new_inode(sb, head, test, set, data);
}
EXPORT_SYMBOL(iget5_locked);

/**
 * iget_locked - obtain an inode from a mounted file system
 * @sb:		super block of file system
 * @ino:	inode number to get
 *
 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
 * the inode cache and if present it is returned with an increased reference
 * count. This is for file systems where the inode number is sufficient for
 * unique identification of an inode.
 *
 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
 * The file system gets to fill it in before unlocking it via
 * unlock_new_inode().
 */
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
	struct hlist_head *head = inode_hashtable + hash(sb, ino);
	struct inode *inode;

	inode = ifind_fast(sb, head, ino);
	if (inode)
		return inode;
	/*
	 * get_new_inode_fast() will do the right thing, re-trying the search
	 * in case it had to block at any point.
	 */
	return get_new_inode_fast(sb, head, ino);
}
EXPORT_SYMBOL(iget_locked);

A
Al Viro 已提交
1089 1090 1091 1092 1093 1094
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);

C
Christoph Hellwig 已提交
1095
	inode->i_state |= I_NEW;
A
Al Viro 已提交
1096
	while (1) {
1097 1098
		struct hlist_node *node;
		struct inode *old = NULL;
A
Al Viro 已提交
1099
		spin_lock(&inode_lock);
1100 1101 1102 1103 1104
		hlist_for_each_entry(old, node, head, i_hash) {
			if (old->i_ino != ino)
				continue;
			if (old->i_sb != sb)
				continue;
A
Al Viro 已提交
1105
			if (old->i_state & (I_FREEING|I_WILL_FREE))
1106 1107 1108 1109
				continue;
			break;
		}
		if (likely(!node)) {
A
Al Viro 已提交
1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode_lock);
			return 0;
		}
		__iget(old);
		spin_unlock(&inode_lock);
		wait_on_inode(old);
		if (unlikely(!hlist_unhashed(&old->i_hash))) {
			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);

C
Christoph Hellwig 已提交
1132
	inode->i_state |= I_NEW;
A
Al Viro 已提交
1133 1134

	while (1) {
1135 1136 1137
		struct hlist_node *node;
		struct inode *old = NULL;

A
Al Viro 已提交
1138
		spin_lock(&inode_lock);
1139 1140 1141 1142 1143
		hlist_for_each_entry(old, node, head, i_hash) {
			if (old->i_sb != sb)
				continue;
			if (!test(old, data))
				continue;
A
Al Viro 已提交
1144
			if (old->i_state & (I_FREEING|I_WILL_FREE))
1145 1146 1147 1148
				continue;
			break;
		}
		if (likely(!node)) {
A
Al Viro 已提交
1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
			hlist_add_head(&inode->i_hash, head);
			spin_unlock(&inode_lock);
			return 0;
		}
		__iget(old);
		spin_unlock(&inode_lock);
		wait_on_inode(old);
		if (unlikely(!hlist_unhashed(&old->i_hash))) {
			iput(old);
			return -EBUSY;
		}
		iput(old);
	}
}
EXPORT_SYMBOL(insert_inode_locked4);

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/**
 *	__insert_inode_hash - hash an inode
 *	@inode: unhashed inode
 *	@hashval: unsigned long value used to locate this object in the
 *		inode_hashtable.
 *
 *	Add an inode to the inode hash for this superblock.
 */
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
	struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
	spin_lock(&inode_lock);
	hlist_add_head(&inode->i_hash, head);
	spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);

/**
 *	remove_inode_hash - remove an inode from the hash
 *	@inode: inode to unhash
 *
 *	Remove an inode from the superblock.
 */
void remove_inode_hash(struct inode *inode)
{
	spin_lock(&inode_lock);
	hlist_del_init(&inode->i_hash);
	spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(remove_inode_hash);

/*
 * Tell the filesystem that this inode is no longer of any interest and should
 * be completely destroyed.
 *
 * We leave the inode in the inode hash table until *after* the filesystem's
 * ->delete_inode completes.  This ensures that an iget (such as nfsd might
 * instigate) will always find up-to-date information either in the hash or on
 * disk.
 *
 * I_FREEING is set so that no-one will take a new reference to the inode while
 * it is being deleted.
 */
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void generic_delete_inode(struct inode *inode)
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{
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	list_del_init(&inode->i_list);
	list_del_init(&inode->i_sb_list);
1212
	WARN_ON(inode->i_state & I_NEW);
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	inode->i_state |= I_FREEING;
	inodes_stat.nr_inodes--;
	spin_unlock(&inode_lock);

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	evict(inode, 1);

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	spin_lock(&inode_lock);
	hlist_del_init(&inode->i_hash);
	spin_unlock(&inode_lock);
	wake_up_inode(inode);
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	BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
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	destroy_inode(inode);
}
EXPORT_SYMBOL(generic_delete_inode);

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/**
 *	generic_detach_inode - remove inode from inode lists
 *	@inode: inode to remove
 *
 *	Remove inode from inode lists, write it if it's dirty. This is just an
 *	internal VFS helper exported for hugetlbfs. Do not use!
 *
 *	Returns 1 if inode should be completely destroyed.
 */
1237
static int generic_detach_inode(struct inode *inode)
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{
	struct super_block *sb = inode->i_sb;

	if (!hlist_unhashed(&inode->i_hash)) {
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		if (!(inode->i_state & (I_DIRTY|I_SYNC)))
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			list_move(&inode->i_list, &inode_unused);
		inodes_stat.nr_unused++;
1245
		if (sb->s_flags & MS_ACTIVE) {
1246
			spin_unlock(&inode_lock);
1247
			return 0;
1248
		}
1249
		WARN_ON(inode->i_state & I_NEW);
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		inode->i_state |= I_WILL_FREE;
		spin_unlock(&inode_lock);
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		write_inode_now(inode, 1);
		spin_lock(&inode_lock);
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		WARN_ON(inode->i_state & I_NEW);
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		inode->i_state &= ~I_WILL_FREE;
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		inodes_stat.nr_unused--;
		hlist_del_init(&inode->i_hash);
	}
	list_del_init(&inode->i_list);
	list_del_init(&inode->i_sb_list);
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	WARN_ON(inode->i_state & I_NEW);
1262
	inode->i_state |= I_FREEING;
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	inodes_stat.nr_inodes--;
	spin_unlock(&inode_lock);
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	return 1;
}

static void generic_forget_inode(struct inode *inode)
{
	if (!generic_detach_inode(inode))
		return;
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	evict(inode, 0);
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	wake_up_inode(inode);
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	destroy_inode(inode);
}

/*
 * Normal UNIX filesystem behaviour: delete the
 * inode when the usage count drops to zero, and
 * i_nlink is zero.
 */
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void generic_drop_inode(struct inode *inode)
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{
	if (!inode->i_nlink)
		generic_delete_inode(inode);
	else
		generic_forget_inode(inode);
}
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EXPORT_SYMBOL_GPL(generic_drop_inode);

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/*
 * Called when we're dropping the last reference
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 * to an inode.
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 *
 * Call the FS "drop()" function, defaulting to
 * the legacy UNIX filesystem behaviour..
 *
 * NOTE! NOTE! NOTE! We're called with the inode lock
 * held, and the drop function is supposed to release
 * the lock!
 */
static inline void iput_final(struct inode *inode)
{
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	const struct super_operations *op = inode->i_sb->s_op;
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	void (*drop)(struct inode *) = generic_drop_inode;

	if (op && op->drop_inode)
		drop = op->drop_inode;
	drop(inode);
}

/**
1313
 *	iput	- put an inode
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 *	@inode: inode to put
 *
 *	Puts an inode, dropping its usage count. If the inode use count hits
 *	zero, the inode is then freed and may also be destroyed.
 *
 *	Consequently, iput() can sleep.
 */
void iput(struct inode *inode)
{
	if (inode) {
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		BUG_ON(inode->i_state & I_CLEAR);
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		if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
			iput_final(inode);
	}
}
EXPORT_SYMBOL(iput);

/**
 *	bmap	- find a block number in a file
 *	@inode: inode of file
 *	@block: block to find
 *
 *	Returns the block number on the device holding the inode that
 *	is the disk block number for the block of the file requested.
 *	That is, asked for block 4 of inode 1 the function will return the
1340
 *	disk block relative to the disk start that holds that block of the
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 *	file.
 */
1343
sector_t bmap(struct inode *inode, sector_t block)
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{
	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);

1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385
/*
 * With relative atime, only update atime if the previous atime is
 * earlier than either the ctime or mtime or if at least a day has
 * passed since the last atime update.
 */
static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
			     struct timespec now)
{

	if (!(mnt->mnt_flags & MNT_RELATIME))
		return 1;
	/*
	 * Is mtime younger than atime? If yes, update atime:
	 */
	if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
		return 1;
	/*
	 * Is ctime younger than atime? If yes, update atime:
	 */
	if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
		return 1;

	/*
	 * Is the previous atime value older than a day? If yes,
	 * update atime:
	 */
	if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
		return 1;
	/*
	 * Good, we can skip the atime update:
	 */
	return 0;
}

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/**
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 *	touch_atime	-	update the access time
 *	@mnt: mount the inode is accessed on
1389
 *	@dentry: dentry accessed
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 *
 *	Update the accessed time on an inode and mark it for writeback.
 *	This function automatically handles read only file systems and media,
 *	as well as the "noatime" flag and inode specific "noatime" markers.
 */
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void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
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{
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	struct inode *inode = dentry->d_inode;
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	struct timespec now;

1400
	if (inode->i_flags & S_NOATIME)
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		return;
1402
	if (IS_NOATIME(inode))
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		return;
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	if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
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		return;
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1407
	if (mnt->mnt_flags & MNT_NOATIME)
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		return;
1409
	if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
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		return;
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	now = current_fs_time(inode->i_sb);
1413 1414

	if (!relatime_need_update(mnt, inode, now))
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		return;
1416

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

	if (mnt_want_write(mnt))
		return;
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	inode->i_atime = now;
	mark_inode_dirty_sync(inode);
1425
	mnt_drop_write(mnt);
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}
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EXPORT_SYMBOL(touch_atime);
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/**
1430 1431
 *	file_update_time	-	update mtime and ctime time
 *	@file: file accessed
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 *
1433 1434 1435 1436
 *	Update the mtime and ctime members of an inode and mark the inode
 *	for writeback.  Note that this function is meant exclusively for
 *	usage in the file write path of filesystems, and filesystems may
 *	choose to explicitly ignore update via this function with the
1437
 *	S_NOCMTIME inode flag, e.g. for network filesystem where these
1438
 *	timestamps are handled by the server.
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 */

1441
void file_update_time(struct file *file)
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{
1443
	struct inode *inode = file->f_path.dentry->d_inode;
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	struct timespec now;
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	enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
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	/* First try to exhaust all avenues to not sync */
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	if (IS_NOCMTIME(inode))
		return;
1450

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	now = current_fs_time(inode->i_sb);
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	if (!timespec_equal(&inode->i_mtime, &now))
		sync_it = S_MTIME;
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	if (!timespec_equal(&inode->i_ctime, &now))
		sync_it |= S_CTIME;
1457

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	if (IS_I_VERSION(inode))
		sync_it |= S_VERSION;
1460

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	if (!sync_it)
		return;

	/* Finally allowed to write? Takes lock. */
	if (mnt_want_write_file(file))
		return;

	/* Only change inode inside the lock region */
	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);
1476
	mnt_drop_write(file->f_path.mnt);
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}
1478
EXPORT_SYMBOL(file_update_time);
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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;
}
1495
EXPORT_SYMBOL(inode_wait);
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/*
1498 1499 1500 1501 1502 1503
 * If we try to find an inode in the inode hash while it is being
 * deleted, we have to wait until the filesystem completes its
 * deletion before reporting that it isn't found.  This function waits
 * until the deletion _might_ have completed.  Callers are responsible
 * to recheck inode state.
 *
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 * It doesn't matter if I_NEW is not set initially, a call to
1505 1506
 * wake_up_inode() after removing from the hash list will DTRT.
 *
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 * This is called with inode_lock held.
 */
static void __wait_on_freeing_inode(struct inode *inode)
{
	wait_queue_head_t *wq;
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	DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
	wq = bit_waitqueue(&inode->i_state, __I_NEW);
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	prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
	spin_unlock(&inode_lock);
	schedule();
	finish_wait(wq, &wait.wait);
	spin_lock(&inode_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);

/*
 * Initialize the waitqueues and inode hash table.
 */
void __init inode_init_early(void)
{
	int loop;

	/* If hashes are distributed across NUMA nodes, defer
	 * hash allocation until vmalloc space is available.
	 */
	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 < (1 << i_hash_shift); loop++)
		INIT_HLIST_HEAD(&inode_hashtable[loop]);
}

1558
void __init inode_init(void)
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{
	int loop;

	/* inode slab cache */
1563 1564 1565 1566 1567
	inode_cachep = kmem_cache_create("inode_cache",
					 sizeof(struct inode),
					 0,
					 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
					 SLAB_MEM_SPREAD),
1568
					 init_once);
1569
	register_shrinker(&icache_shrinker);
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	/* Hash may have been set up in inode_init_early */
	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 < (1 << 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
1603 1604 1605
		printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
				  " inode %s:%lu\n", mode, inode->i_sb->s_id,
				  inode->i_ino);
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}
EXPORT_SYMBOL(init_special_inode);
1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627

/**
 * Init uid,gid,mode for new inode according to posix standards
 * @inode: New inode
 * @dir: Directory inode
 * @mode: mode of the new inode
 */
void inode_init_owner(struct inode *inode, const struct inode *dir,
			mode_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);