Re: [PATCH] Btrfs: merge inode_list in __merge_refs

[Alexander Block <ablock84@googlemail.com>]

On Thu, Nov 8, 2012 at 10:27 PM, Alexander Block
<ablock84@googlemail.com> wrote:
> When __merge_refs merges two refs, it is also needed to merge the
> inode_list of both refs. Otherwise we have missed backrefs and memory
> leaks. This happens for example if two inodes share an extent and
> both lie in the same leaf and thus also have the same parent.
>
> Signed-off-by: Alexander Block <ablock84@googlemail.com>
> Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
> ---
>  fs/btrfs/backref.c |   13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index 208d8aa..aea6d2d 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -461,6 +461,7 @@ static int __merge_refs(struct list_head *head, int mode)
>                      pos2 = n2, n2 = pos2->next) {
>                         struct __prelim_ref *ref2;
>                         struct __prelim_ref *xchg;
> +                       struct extent_inode_elem *eie;
>
>                         ref2 = list_entry(pos2, struct __prelim_ref, list);
>
> @@ -472,12 +473,20 @@ static int __merge_refs(struct list_head *head, int mode)
>                                         ref1 = ref2;
>                                         ref2 = xchg;
>                                 }
> -                               ref1->count += ref2->count;
>                         } else {
>                                 if (ref1->parent != ref2->parent)
>                                         continue;
> -                               ref1->count += ref2->count;
>                         }
> +
> +                       eie = ref1->inode_list;
> +                       while (eie && eie->next)
> +                               eie = eie->next;
> +                       if (eie)
> +                               eie->next = ref2->inode_list;
> +                       else
> +                               ref1->inode_list = ref2->inode_list;
> +                       ref1->count += ref2->count;
> +
>                         list_del(&ref2->list);
>                         kfree(ref2);
>                 }
> --
> 1.7.10.4
>

Used wrong CC for stable list. Corrected now.