btrfs: move ino_cache_inode dropping out of btrfs_free_fs_root

We are going to make root life be controlled soley by refcounting, and
inodes will be one of the things that hold a ref on the root.  This
means we need to handle dropping the ino_cache_inode outside of the root
freeing logic, so move it into btrfs_drop_and_free_fs_root() so it is
cleaned up properly on unmount.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -3912,12 +3912,15 @@ void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
 		__btrfs_remove_free_space_cache(root->free_ino_pinned);
 	if (root->free_ino_ctl)
 		__btrfs_remove_free_space_cache(root->free_ino_ctl);
+	if (root->ino_cache_inode) {
+		iput(root->ino_cache_inode);
+		root->ino_cache_inode = NULL;
+	}
 	btrfs_free_fs_root(root);
 }
 
 void btrfs_free_fs_root(struct btrfs_root *root)
 {
-	iput(root->ino_cache_inode);
 	WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
 	if (root->anon_dev)
 		free_anon_bdev(root->anon_dev);

fs/btrfs/transaction.c

@@ -2424,6 +2424,10 @@ int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
 	btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
 
 	btrfs_kill_all_delayed_nodes(root);
+	if (root->ino_cache_inode) {
+		iput(root->ino_cache_inode);
+		root->ino_cache_inode = NULL;
+	}
 
 	if (btrfs_header_backref_rev(root->node) <
 			BTRFS_MIXED_BACKREF_REV)