On 2020/6/10 下午8:32, Johannes Thumshirn wrote:
> In btrfs_alloc_chunk_ctrl() we have a recurring pattern, first we assign
> num stripes, then we test if num_stripes is smaller than a hardcoded
> boundary and after that we set min_stripes to this magic value.
>
> Reverse the logic by first assigning min_stripes and then testing
> num_stripes against min_stripes.
>
> This will help further refactoring.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
I'm wondering why we don't use btrfs_raid_attr::devs_min.
In fact, I'm a little surprised why use so little of that structure, but
relies on so many if branches to do the check.
Thanks,
Qu
> ---
> volumes.c | 30 +++++++++++++++---------------
> 1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/volumes.c b/volumes.c
> index 7f84fbbaa742..089363f66473 100644
> --- a/volumes.c
> +++ b/volumes.c
> @@ -1054,25 +1054,25 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
> }
> }
> if (type & BTRFS_BLOCK_GROUP_RAID1) {
> - num_stripes = min_t(u64, 2,
> + min_stripes = 2;
> + num_stripes = min_t(u64, min_stripes,
> btrfs_super_num_devices(info->super_copy));
> - if (num_stripes < 2)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> - min_stripes = 2;
> }
> if (type & BTRFS_BLOCK_GROUP_RAID1C3) {
> - num_stripes = min_t(u64, 3,
> + min_stripes = 3;
> + num_stripes = min_t(u64, min_stripes,
> btrfs_super_num_devices(info->super_copy));
> - if (num_stripes < 3)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> - min_stripes = 3;
> }
> if (type & BTRFS_BLOCK_GROUP_RAID1C4) {
> - num_stripes = min_t(u64, 4,
> + min_stripes = 4;
> + num_stripes = min_t(u64, min_stripes,
> btrfs_super_num_devices(info->super_copy));
> - if (num_stripes < 4)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> - min_stripes = 4;
> }
> if (type & BTRFS_BLOCK_GROUP_DUP) {
> num_stripes = 2;
> @@ -1085,32 +1085,32 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
> min_stripes = 2;
> }
> if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
> + min_stripes = 4;
> num_stripes = btrfs_super_num_devices(info->super_copy);
> if (num_stripes > max_stripes)
> num_stripes = max_stripes;
> - if (num_stripes < 4)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> num_stripes &= ~(u32)1;
> sub_stripes = 2;
> - min_stripes = 4;
> }
> if (type & (BTRFS_BLOCK_GROUP_RAID5)) {
> + min_stripes = 2;
> num_stripes = btrfs_super_num_devices(info->super_copy);
> if (num_stripes > max_stripes)
> num_stripes = max_stripes;
> - if (num_stripes < 2)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> - min_stripes = 2;
> stripe_len = find_raid56_stripe_len(num_stripes - 1,
> btrfs_super_stripesize(info->super_copy));
> }
> if (type & (BTRFS_BLOCK_GROUP_RAID6)) {
> + min_stripes = 3;
> num_stripes = btrfs_super_num_devices(info->super_copy);
> if (num_stripes > max_stripes)
> num_stripes = max_stripes;
> - if (num_stripes < 3)
> + if (num_stripes < min_stripes)
> return -ENOSPC;
> - min_stripes = 3;
> stripe_len = find_raid56_stripe_len(num_stripes - 2,
> btrfs_super_stripesize(info->super_copy));
> }
>
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