[PATCH] Btrfs: merge inode_list in __merge_refs

[PATCH] Btrfs: merge inode_list in __merge_refs

[Alexander Block]

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

Re: [PATCH] Btrfs: merge inode_list in __merge_refs

[Alexander Block]

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.

Re: [PATCH] Btrfs: merge inode_list in __merge_refs

[Greg KH]

On Thu, Nov 08, 2012 at 10:35:19PM +0100, Alexander Block wrote:
> 
> Used wrong CC for stable list. Corrected now.

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>