On Thu, Jun 23, 2011 at 11:36 AM, David Sterba <dave@xxxxxxxx> wrote:
> On Thu, Jun 23, 2011 at 11:01:01PM +0800, Daniel J Blueman wrote:
>> On 23 June 2011 18:31, David Sterba <dave@xxxxxxxx> wrote:
>> (how does one follow up an email in git send-email with the message id?)
>
> git-send-email --in-reply-to=<identifier>
>
> (if it does not ask for it) and paste identifier from mail header
> In-Reply-To:
>
>> If lookup_extent_backref fails, path->nodes[0] reasonably could be
>> null along with other callers of btrfs_print_leaf, so ensure we have a
>> valid extent buffer before dereferencing.
>
> ack.
>
>
> thanks,
> david
>
>>
>> Signed-off-by: Daniel J Blueman <daniel.blueman@xxxxxxxxx>
>>
>> diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
>> index fb2605d..f38e452 100644
>> --- a/fs/btrfs/print-tree.c
>> +++ b/fs/btrfs/print-tree.c
>> @@ -158,8 +158,7 @@ static void print_extent_ref_v0(struct
>> extent_buffer *eb, int slot)
>> void btrfs_print_leaf(struct btrfs_root *root, struct extent_buffer *l)
>> {
>> int i;
>> - u32 type;
>> - u32 nr = btrfs_header_nritems(l);
>> + u32 type, nr;
>> struct btrfs_item *item;
>> struct btrfs_root_item *ri;
>> struct btrfs_dir_item *di;
>> @@ -172,6 +171,11 @@ void btrfs_print_leaf(struct btrfs_root *root,
>> struct extent_buffer *l)
>> struct btrfs_key key;
>> struct btrfs_key found_key;
>>
>> + if (!l)
>> + return;
>> +
>> + nr = btrfs_header_nritems(l);
>> +
>> printk(KERN_INFO "leaf %llu total ptrs %d free space %d\n",
>> (unsigned long long)btrfs_header_bytenr(l), nr,
>> btrfs_leaf_free_space(root, l));
>> --
>> Daniel J Blueman
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I've also run into a corruption with spots where path->nodes[0] has a
value of NULL.
But, I'm getting the error showing up elsewhere when I try to mount
the partition:
[ 6168.790849] device fsid 7c35237f-d72a-4d65-bd01-b853d853c17a devid
1 transid 507394 /dev/sdb6
[ 6168.832825] attempt to access beyond end of device
[ 6168.832831] sdb6: rw=0, want=20033720, limit=20016927
[ 6168.832843] Failed to read block groups: -5
[ 6168.833663] btrfs: open_ctree failed
In my case, I need to handle the corruption earlier in order to
properly handle the error.
Btrfs-progs also has troubles handling this corruption (debugging
btrfsck was how I discovered I was running into path->nodes[0] ==
NULL).
For reference, I'm using a 2.6.39.1 kernel with Chris' latest
'for-linus' branch merged in.
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