Re: [PATCH 2/2] Btrfs: kill some BUG_ONs() in the find_parent_nodes()

[Jan Schmidt <list.btrfs@jan-o-sch.net>]

On Mon, March 25, 2013 at 12:09 (+0100), Wang Shilong wrote:
> From: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
> 
> The reason that BUG_ON() happens in these places is just
> because of ENOMEM. 
> 
> We try ro return ENOMEM rather than trigger BUG_ON(), the
> caller will abort the transaction thus avoiding the kernel panic.
> 
> Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
> ---
>  fs/btrfs/backref.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index bd605c8..a5e2beb 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -900,7 +900,8 @@ again:
>  		if (ref->count && ref->root_id && ref->parent == 0) {
>  			/* no parent == root of tree */
>  			ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
> -			BUG_ON(ret < 0);
> +			if (ret)
> +				goto out;
>  		}
>  		if (ref->count && ref->parent) {
>  			struct extent_inode_elem *eie = NULL;
> @@ -920,6 +921,8 @@ again:
>  			ret = ulist_add_merge(refs, ref->parent,
>  					      (uintptr_t)ref->inode_list,
>  					      (u64 *)&eie, GFP_NOFS);
> +			if (ret)
> +				goto out;
>  			if (!ret && extent_item_pos) {

Remove ret here, too, please.

>  				/*
>  				 * we've recorded that parent, so we must extend
> @@ -930,7 +933,6 @@ again:
>  					eie = eie->next;
>  				eie->next = ref->inode_list;
>  			}
> -			BUG_ON(ret < 0);
>  		}
>  		kfree(ref);
>  	}
> 

Otherwise,

Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

Thanks!
-Jan