Commit b2b2af8e authored by Dave Chinner's avatar Dave Chinner Committed by Al Viro
Browse files

fs: factor inode disposal 



We have a couple of places that dispose of inodes. factor the
disposal into evict() to isolate this code and make it simpler to
peel away the inode_lock from the code.

While doing this, change the logic flow in iput_final() to separate
the different cases that need to be handled to make the transitions
the inode goes through more obvious.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 250df6ed

fs/inode.c

+41 −63
Original line number Diff line number Diff line
@@ -422,17 +422,6 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval) 
}

EXPORT_SYMBOL(__insert_inode_hash);



/**

 *	__remove_inode_hash - remove an inode from the hash

 *	@inode: inode to unhash

 *

 *	Remove an inode from the superblock.

 */

static void __remove_inode_hash(struct inode *inode)

{

	hlist_del_init(&inode->i_hash);

}



/**

 *	remove_inode_hash - remove an inode from the hash

 *	@inode: inode to unhash
@@ -462,10 +451,31 @@ void end_writeback(struct inode *inode) 
}

EXPORT_SYMBOL(end_writeback);



/*

 * Free the inode passed in, removing it from the lists it is still connected

 * to. We remove any pages still attached to the inode and wait for any IO that

 * is still in progress before finally destroying the inode.

 *

 * An inode must already be marked I_FREEING so that we avoid the inode being

 * moved back onto lists if we race with other code that manipulates the lists

 * (e.g. writeback_single_inode). The caller is responsible for setting this.

 *

 * An inode must already be removed from the LRU list before being evicted from

 * the cache. This should occur atomically with setting the I_FREEING state

 * flag, so no inodes here should ever be on the LRU when being evicted.

 */

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));



	spin_lock(&inode_lock);

	list_del_init(&inode->i_wb_list);

	__inode_sb_list_del(inode);

	spin_unlock(&inode_lock);



	if (op->evict_inode) {

		op->evict_inode(inode);

	} else {
@@ -477,6 +487,15 @@ static void evict(struct inode *inode) 
		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);

}



/*
@@ -495,16 +514,6 @@ static void dispose_list(struct list_head *head) 
		list_del_init(&inode->i_lru);



		evict(inode);



		spin_lock(&inode_lock);

		__remove_inode_hash(inode);

		__inode_sb_list_del(inode);

		spin_unlock(&inode_lock);



		spin_lock(&inode->i_lock);

		wake_up_bit(&inode->i_state, __I_NEW);

		spin_unlock(&inode->i_lock);

		destroy_inode(inode);

	}

}
@@ -537,13 +546,7 @@ void evict_inodes(struct super_block *sb) 
		if (!(inode->i_state & (I_DIRTY | I_SYNC)))

			inodes_stat.nr_unused--;

		spin_unlock(&inode->i_lock);



		/*

		 * Move the inode off the IO lists and LRU once I_FREEING is

		 * set so that it won't get moved back on there if it is dirty.

		 */

		list_move(&inode->i_lru, &dispose);

		list_del_init(&inode->i_wb_list);

	}

	spin_unlock(&inode_lock);
@@ -596,13 +599,7 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) 
		if (!(inode->i_state & (I_DIRTY | I_SYNC)))

			inodes_stat.nr_unused--;

		spin_unlock(&inode->i_lock);



		/*

		 * Move the inode off the IO lists and LRU once I_FREEING is

		 * set so that it won't get moved back on there if it is dirty.

		 */

		list_move(&inode->i_lru, &dispose);

		list_del_init(&inode->i_wb_list);

	}

	spin_unlock(&inode_lock);
@@ -699,12 +696,7 @@ static void prune_icache(int nr_to_scan) 
		inode->i_state |= I_FREEING;

		spin_unlock(&inode->i_lock);



		/*

		 * Move the inode off the IO lists and LRU once I_FREEING is

		 * set so that it won't get moved back on there if it is dirty.

		 */

		list_move(&inode->i_lru, &freeable);

		list_del_init(&inode->i_wb_list);

		inodes_stat.nr_unused--;

	}

	if (current_is_kswapd())
@@ -1434,16 +1426,16 @@ static void iput_final(struct inode *inode) 
	else

		drop = generic_drop_inode(inode);



	if (!drop) {

		if (sb->s_flags & MS_ACTIVE) {

	if (!drop && (sb->s_flags & MS_ACTIVE)) {

		inode->i_state |= I_REFERENCED;

			if (!(inode->i_state & (I_DIRTY|I_SYNC))) {

		if (!(inode->i_state & (I_DIRTY|I_SYNC)))

			inode_lru_list_add(inode);

			}

		spin_unlock(&inode->i_lock);

		spin_unlock(&inode_lock);

		return;

	}



	if (!drop) {

		inode->i_state |= I_WILL_FREE;

		spin_unlock(&inode->i_lock);

		spin_unlock(&inode_lock);
@@ -1452,28 +1444,14 @@ static void iput_final(struct inode *inode) 
		spin_lock(&inode->i_lock);

		WARN_ON(inode->i_state & I_NEW);

		inode->i_state &= ~I_WILL_FREE;

		__remove_inode_hash(inode);

	}



	inode->i_state |= I_FREEING;

	spin_unlock(&inode->i_lock);



	/*

	 * Move the inode off the IO lists and LRU once I_FREEING is

	 * set so that it won't get moved back on there if it is dirty.

	 */

	inode_lru_list_del(inode);

	list_del_init(&inode->i_wb_list);



	__inode_sb_list_del(inode);

	spin_unlock(&inode->i_lock);

	spin_unlock(&inode_lock);



	evict(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);

}



/**

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