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Commit 8290c35f authored by David Chinner's avatar David Chinner Committed by Lachlan McIlroy
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Inode: Allow external list initialisation 



To allow XFS to combine the XFS and linux inodes into a single
structure, we need to drive inode lookup from the XFS inode cache,
not the generic inode cache. This means that we need initialise a
struct inode from a context outside alloc_inode() as it is no longer
used by XFS.

After inode allocation and initialisation, we need to add the inode
to the superblock list, the in-use list, hash it and do some
accounting. This all needs to be done with the inode_lock held and
there are already several places in fs/inode.c that do this list
manipulation.  Factor out the common code, add a locking wrapper and
export the function so ti can be called from XFS.

Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent 2cb1599f

fs/inode.c

+46 −21
Original line number Diff line number Diff line
@@ -550,6 +550,49 @@ static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head 
	return node ? inode : NULL;

}



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

 * @sb		- superblock inode belongs to.

 * @inode	- inode to mark in use

 *

 * 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);



/**

 *	new_inode 	- obtain an inode

 *	@sb: superblock
@@ -577,9 +620,7 @@ struct inode *new_inode(struct super_block *sb) 
	inode = alloc_inode(sb);

	if (inode) {

		spin_lock(&inode_lock);

		inodes_stat.nr_inodes++;

		list_add(&inode->i_list, &inode_in_use);

		list_add(&inode->i_sb_list, &sb->s_inodes);

		__inode_add_to_lists(sb, NULL, inode);

		inode->i_ino = ++last_ino;

		inode->i_state = 0;

		spin_unlock(&inode_lock);
@@ -638,10 +679,7 @@ static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *h 
			if (set(inode, data))

				goto set_failed;



			inodes_stat.nr_inodes++;

			list_add(&inode->i_list, &inode_in_use);

			list_add(&inode->i_sb_list, &sb->s_inodes);

			hlist_add_head(&inode->i_hash, head);

			__inode_add_to_lists(sb, head, inode);

			inode->i_state = I_LOCK|I_NEW;

			spin_unlock(&inode_lock);
@@ -687,10 +725,7 @@ static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_he 
		old = find_inode_fast(sb, head, ino);

		if (!old) {

			inode->i_ino = ino;

			inodes_stat.nr_inodes++;

			list_add(&inode->i_list, &inode_in_use);

			list_add(&inode->i_sb_list, &sb->s_inodes);

			hlist_add_head(&inode->i_hash, head);

			__inode_add_to_lists(sb, head, inode);

			inode->i_state = I_LOCK|I_NEW;

			spin_unlock(&inode_lock);
@@ -714,16 +749,6 @@ static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_he 
	return inode;

}



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;

}



/**

 *	iunique - get a unique inode number

 *	@sb: superblock

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -1883,6 +1883,7 @@ extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin); 


extern struct inode * inode_init_always(struct super_block *, struct inode *);

extern void inode_init_once(struct inode *);

extern void inode_add_to_lists(struct super_block *, struct inode *);

extern void iput(struct inode *);

extern struct inode * igrab(struct inode *);

extern ino_t iunique(struct super_block *, ino_t);