Re: kernel BUG at fs/btrfs/extent-tree.c:5038 (linux 3.4.7)

[Olivier Bonvalet <btrfs.list@daevel.fr>]

On 02/08/2012 15:22, David Sterba wrote:
> On Wed, Aug 01, 2012 at 09:48:15PM +0200, Olivier Bonvalet wrote:
>> I have some trouble with a btrfs filesystem.
>> As you can see in logs, there is lines which are from btrfs (I
>> supposed), then some warnings at fs/btrfs/extent-tree.c, and finally a
>> "kernel BUG" at fs/btrfs/extent-tree.c:5038.
>
> Did you really see this BUG ? It comes from some unused and disabled code:
>
> 5036 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
> 5037         if (item_size<  sizeof(*ei)) {
> 5038                 BUG_ON(found_extent || extent_slot != path->slots[0]);
> ^^^^
>
> 5039                 ret = convert_extent_item_v0(trans, extent_root, path,
> 5040                                              owner_objectid, 0);
> 5041                 if (ret<  0)
> 5042                         goto abort;
> 5043
> 5044                 btrfs_release_path(path);
> 5045                 path->leave_spinning = 1;
> 5046
> 5047                 key.objectid = bytenr;
> 5048                 key.type = BTRFS_EXTENT_ITEM_KEY;
> 5049                 key.offset = num_bytes;
> 5050
> 5051                 ret = btrfs_search_slot(trans, extent_root,&key, path,
> 5052                                         -1, 1);
> 5053                 if (ret) {
> 5054                         printk(KERN_ERR "umm, got %d back from search"
> 5055                                ", was looking for %llu\n", ret,
> 5056                                (unsigned long long)bytenr);
> 5057                         btrfs_print_leaf(extent_root, path->nodes[0]);
> 5058                 }
> 5059                 if (ret<  0)
> 5060                         goto abort;
> 5061                 extent_slot = path->slots[0];
> 5062                 leaf = path->nodes[0];
> 5063                 item_size = btrfs_item_size_nr(leaf, extent_slot);
> 5064         }
> 5065 #endif
>
>
> david
>

Yes... it's a copy from my /var/log/kern.log. Is it really "disabled" ?