Re: [PATCH 4/8] btrfs: free the reloc_control in a consistent way

Qu Wenruo
2020-03-05T11:39:50Z

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On 2020/3/5 上午12:18, Josef Bacik wrote:
> If we have an error while processing the reloc roots we could leak roots
> that were added to rc->reloc_roots before we hit the error. We could
> have also not removed the reloct tree mapping from our rb_tree, so clean
> up any remaining nodes in the reloc root rb_tree.
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
> fs/btrfs/relocation.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index c496f8ed8c7e..f6237d885fe0 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -4387,6 +4387,20 @@ static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
> return rc;
> }
>
> +static void free_reloc_control(struct reloc_control *rc)
> +{
> + struct rb_node *rb_node;
> + struct mapping_node *node;
> +
> + free_reloc_roots(&rc->reloc_roots);
> + while ((rb_node = rb_first(&rc->reloc_root_tree.rb_root))) {

rbtree_postorder_for_each_entry_safe().

So that we don't need to bother the re-balance of rbtree.

Thanks,
Qu

> + node = rb_entry(rb_node, struct mapping_node, rb_node);
> + rb_erase(rb_node, &rc->reloc_root_tree.rb_root);
> + kfree(node);
> + }
> + kfree(rc);
> +}
> +
> /*
> * Print the block group being relocated
> */
> @@ -4531,7 +4545,7 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
> btrfs_dec_block_group_ro(rc->block_group);
> iput(rc->data_inode);
> btrfs_put_block_group(rc->block_group);
> - kfree(rc);
> + free_reloc_control(rc);
> return err;
> }
>
> @@ -4708,7 +4722,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
> out_unset:
> unset_reloc_control(rc);
> out_free:
> - kfree(rc);
> + free_reloc_control(rc);
> out:
> if (!list_empty(&reloc_roots))
> free_reloc_roots(&reloc_roots);
>

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