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

Omar Sandoval
2018-09-01T04:20:48Z

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
>