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

Josef Bacik
2020-03-13T15:32:41Z

On 3/13/20 11:18 AM, David Sterba wrote:
> On Thu, Mar 05, 2020 at 07:39:33PM +0800, Qu Wenruo wrote:
>>
>>
>> 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.
>
> I'll update the patch with this
>
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -4240,15 +4240,13 @@ static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
>
> static void free_reloc_control(struct reloc_control *rc)
> {
> - struct rb_node *rb_node;
> - struct mapping_node *node;
> + struct mapping_node *node, *tmp;
>
> free_reloc_roots(&rc->reloc_roots);
> - while ((rb_node = rb_first(&rc->reloc_root_tree.rb_root))) {
> - node = rb_entry(rb_node, struct mapping_node, rb_node);
> - rb_erase(rb_node, &rc->reloc_root_tree.rb_root);
> + rbtree_postorder_for_each_entry_safe(node, tmp,
> + &rc->reloc_root_tree.rb_root, rb_node)
> kfree(node);

You need an rb_erase() in here. I'm updating the series so I'll fix it before I
send the new set. Thanks,

Josef