On Tue, Aug 23, 2016 at 05:37:45PM -0700, Liu Bo wrote:
> When btree node (level = 1) has nritems which equals to zero,
> we can end up with panic due to insert_ptr()'s
>
> BUG_ON(slot > nritems);
>
> where slot is 1 and nritems is 0, as copy_for_split() calls
> insert_ptr(.., path->slots[1] + 1, ...);
>
> A invalid value results in the whole mess, this adds the check
> for btree's node nritems so that we stop reading block when
> when something is wrong.
>
> Signed-off-by: Liu Bo <bo.li....@oracle.com>
Reviewed-by: David Sterba <dste...@suse.com>
> ---
> v2: - remove unnecessary "noinline"
> - fix to do the proper check as BTRFS_NODEPTRS_PER_BLOCK(root) is
> inclusive and nr is unsigned.
>
> fs/btrfs/disk-io.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 90f57fa..682816d 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -633,6 +633,19 @@ static noinline int check_leaf(struct btrfs_root *root,
> return 0;
> }
>
> +static int check_node(struct btrfs_root *root, struct extent_buffer *node)
> +{
> + unsigned long nr = btrfs_header_nritems(node);
> +
> + if (nr == 0 || nr > BTRFS_NODEPTRS_PER_BLOCK(root)) {
> + btrfs_crit(root->fs_info,
> + "corrupt node: block %llu root %llu nritems %lu\n",
I'll drop the newline.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
