btrfs: use ->free_inode()

a lot of stuff remains in ->destroy_inode()
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/btrfs/ctree.h

@@ -3267,6 +3267,7 @@ void btrfs_evict_inode(struct inode *inode);
 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc);
 struct inode *btrfs_alloc_inode(struct super_block *sb);
 void btrfs_destroy_inode(struct inode *inode);
+void btrfs_free_inode(struct inode *inode);
 int btrfs_drop_inode(struct inode *inode);
 int __init btrfs_init_cachep(void);
 void __cold btrfs_destroy_cachep(void);

fs/btrfs/inode.c

@@ -9206,9 +9206,8 @@ void btrfs_test_destroy_inode(struct inode *inode)
 }
 #endif
 
-static void btrfs_i_callback(struct rcu_head *head)
+void btrfs_free_inode(struct inode *inode)
 {
-	struct inode *inode = container_of(head, struct inode, i_rcu);
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
@@ -9234,7 +9233,7 @@ void btrfs_destroy_inode(struct inode *inode)
 	 * created.
 	 */
 	if (!root)
-		goto free;
+		return;
 
 	while (1) {
 		ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
@@ -9252,8 +9251,6 @@ void btrfs_destroy_inode(struct inode *inode)
 	btrfs_qgroup_check_reserved_leak(inode);
 	inode_tree_del(inode);
 	btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
-free:
-	call_rcu(&inode->i_rcu, btrfs_i_callback);
 }
 
 int btrfs_drop_inode(struct inode *inode)

fs/btrfs/super.c

@@ -2298,6 +2298,7 @@ static const struct super_operations btrfs_super_ops = {
 	.show_devname	= btrfs_show_devname,
 	.alloc_inode	= btrfs_alloc_inode,
 	.destroy_inode	= btrfs_destroy_inode,
+	.free_inode	= btrfs_free_inode,
 	.statfs		= btrfs_statfs,
 	.remount_fs	= btrfs_remount,
 	.freeze_fs	= btrfs_freeze,