Re: [PATCH 1/6] btrfs-progs: Exit gracefully if we hit ENOSPC when allocating tree block

[Nikolay Borisov <nborisov@suse.com>]

On  3.08.2018 08:50, Qu Wenruo wrote:
> When running test fuzz/003, we could hit the following BUG_ON:
> ------
> ====== RUN MAYFAIL /home/adam/btrfs/btrfs-progs/btrfs check --init-csum-tree /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-155621-bad-block-group-offset.raw.restored
> Unable to find block group for 0
> Unable to find block group for 0
> Unable to find block group for 0
> extent-tree.c:2657: alloc_tree_block: BUG_ON `ret` triggered, value -28
> failed (ignored, ret=134): /home/adam/btrfs/btrfs-progs/btrfs check --init-csum-tree /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-155621-bad-block-group-offset.raw.restored
> mayfail: returned code 134 (SIGABRT), not ignored
> test failed for case 003-multi-check-unmounted
> ------
> 
> Just remove that BUG_ON() and allow us to exit gracefully.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

However there are a lot more BUG_ONs in btrfs_reserve_extent :(
> ---
>  extent-tree.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/extent-tree.c b/extent-tree.c
> index b9d51b388c9a..a1f711ece7a8 100644
> --- a/extent-tree.c
> +++ b/extent-tree.c
> @@ -2654,7 +2654,10 @@ static int alloc_tree_block(struct btrfs_trans_handle *trans,
>  
>  	ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
>  				   hint_byte, search_end, ins, 0);
> -	BUG_ON(ret);
> +	if (ret < 0) {
> +		btrfs_free_delayed_extent_op(extent_op);
> +		return ret;
> +	}
>  
>  	if (key)
>  		memcpy(&extent_op->key, key, sizeof(extent_op->key));
>