Re: [PATCH 22/35] btrfs: make sure we create all new bgs

[Omar Sandoval <osandov@osandov.com>]

On Thu, Aug 30, 2018 at 01:42:12PM -0400, Josef Bacik wrote:
> We can actually allocate new chunks while we're creating our bg's, so
> instead of doing list_for_each_safe, just do while (!list_empty()) so we
> make sure to catch any new bg's that get added to the list.

Reviewed-by: Omar Sandoval <osandov@fb.com>

Since Nikolay pointed it out, might as well mention in the commit
message that this can happen because we modify the chunk and extent
trees.

> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  fs/btrfs/extent-tree.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index ca98c39308f6..fc30ff96f0d6 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -10331,7 +10331,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
>  void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
>  {
>  	struct btrfs_fs_info *fs_info = trans->fs_info;
> -	struct btrfs_block_group_cache *block_group, *tmp;
> +	struct btrfs_block_group_cache *block_group;
>  	struct btrfs_root *extent_root = fs_info->extent_root;
>  	struct btrfs_block_group_item item;
>  	struct btrfs_key key;
> @@ -10339,7 +10339,10 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
>  	bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
>  
>  	trans->can_flush_pending_bgs = false;
> -	list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
> +	while (!list_empty(&trans->new_bgs)) {
> +		block_group = list_first_entry(&trans->new_bgs,
> +					       struct btrfs_block_group_cache,
> +					       bg_list);
>  		if (ret)
>  			goto next;
>  
> -- 
> 2.14.3
>