On Mon, Aug 23, 2010 at 09:23:44AM +0800, Li Zefan wrote:
> When adding a new extent, we'll firstly see if we can merge
> this extent to the left or/and right extent. Extract this as
> a helper try_merge_free_space().
>
> As a side effect, we fix a small bug that if the new extent
> has non-bitmap left entry but is unmergeble, we'll directly
> link the extent without trying to drop it into bitmap.
>
> This also prepares for the next patch.
>
> Signed-off-by: Li Zefan <l...@cn.fujitsu.com>
> ---
> fs/btrfs/free-space-cache.c | 75 ++++++++++++++++++++++++------------------
> 1 files changed, 43 insertions(+), 32 deletions(-)
>
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index 20f3141..faeec8f 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -610,22 +610,14 @@ out:
> return ret;
> }
>
> -int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
> - u64 offset, u64 bytes)
> +bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
> + struct btrfs_free_space *info)
> {
> - struct btrfs_free_space *right_info = NULL;
> - struct btrfs_free_space *left_info = NULL;
> - struct btrfs_free_space *info = NULL;
> - int ret = 0;
> -
> - info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
> - if (!info)
> - return -ENOMEM;
> -
> - info->offset = offset;
> - info->bytes = bytes;
> -
> - spin_lock(&block_group->tree_lock);
> + struct btrfs_free_space *left_info;
> + struct btrfs_free_space *right_info;
> + bool merged = false;
> + u64 offset = info->offset;
> + u64 bytes = info->bytes;
>
> /*
> * first we want to see if there is free space adjacent to the range we
> @@ -639,27 +631,11 @@ int btrfs_add_free_space(struct btrfs_block_group_cache
> *block_group,
> else
> left_info = tree_search_offset(block_group, offset - 1, 0, 0);
>
> - /*
> - * If there was no extent directly to the left or right of this new
> - * extent then we know we're going to have to allocate a new extent, so
> - * before we do that see if we need to drop this into a bitmap
> - */
> - if ((!left_info || left_info->bitmap) &&
> - (!right_info || right_info->bitmap)) {
> - ret = insert_into_bitmap(block_group, info);
> -
> - if (ret < 0) {
> - goto out;
> - } else if (ret) {
> - ret = 0;
> - goto out;
> - }
> - }
> -
> if (right_info && !right_info->bitmap) {
> unlink_free_space(block_group, right_info);
> info->bytes += right_info->bytes;
> kfree(right_info);
> + merged = true;
> }
>
> if (left_info && !left_info->bitmap &&
> @@ -668,8 +644,43 @@ int btrfs_add_free_space(struct btrfs_block_group_cache
> *block_group,
> info->offset = left_info->offset;
> info->bytes += left_info->bytes;
> kfree(left_info);
> + merged = true;
> }
>
> + return merged;
> +}
> +
> +int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
> + u64 offset, u64 bytes)
> +{
> + struct btrfs_free_space *info;
> + int ret = 0;
> +
> + info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
> + if (!info)
> + return -ENOMEM;
> +
> + info->offset = offset;
> + info->bytes = bytes;
> +
> + spin_lock(&block_group->tree_lock);
> +
> + if (try_merge_free_space(block_group, info))
> + goto link;
> +
> + /*
> + * There was no extent directly to the left or right of this new
> + * extent then we know we're going to have to allocate a new extent, so
> + * before we do that see if we need to drop this into a bitmap
> + */
> + ret = insert_into_bitmap(block_group, info);
> + if (ret < 0) {
> + goto out;
> + } else if (ret) {
> + ret = 0;
> + goto out;
> + }
> +link:
> ret = link_free_space(block_group, info);
> if (ret)
> kfree(info);
> --
> 1.7.0.1
>
Reviewed-by: Josef Bacik <jo...@redhat.com>
Thanks,
Josef
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