On 2018年05月07日 15:46, Qu Wenruo wrote: > Normally corrupted leaf should be caught by csum check, but sometimes > corrupted item pointers (out of leaf range) can still pass csum check. > In fact, our fsck/005 test case image has such corrupted item pointer > and btrfs check can surprisingly fix it. > > Anyway, make print-tree to skip such item and remaining slots to avoid > segfault. > > Please note that, in btrfs-progs we can't put such check into > check_tree_block() nor do kernel level comprehensive check as under > certain case, btrfs-progs can handle or even repair it. > A restrict check_tree_block() or backporting kernel btrfs_check_leaf() > could break such test cases and reduce the utility of btrfs-progs. > > Issue: #128 > Reported-by: Hubert Kario <ka...@wit.edu.pl>
Mail changed to <hub...@kario.pl> (Github version already updated.)
Thanks,
Qu
> Signed-off-by: Qu Wenruo <w...@suse.com>
> ---
> print-tree.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/print-tree.c b/print-tree.c
> index a1a7954abdae..aaff0f618b7e 100644
> --- a/print-tree.c
> +++ b/print-tree.c
> @@ -1179,6 +1179,7 @@ void btrfs_print_leaf(struct extent_buffer *eb)
> struct btrfs_item *item;
> struct btrfs_disk_key disk_key;
> char flags_str[128];
> + u32 leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
> u32 i;
> u32 nr;
> u64 flags;
> @@ -1207,6 +1208,23 @@ void btrfs_print_leaf(struct extent_buffer *eb)
> u32 type;
> u64 offset;
>
> + /*
> + * Extra check on item pointers
> + * Here we don't need to be as restrict as kernel leaf check.
> + * Only need to ensure all pointers are pointing range inside
> + * the leaf, thus no segfault.
> + */
> + if (btrfs_item_offset_nr(eb, i) > leaf_data_size ||
> + btrfs_item_size_nr(eb, i) + btrfs_item_offset_nr(eb, i) >
> + leaf_data_size) {
> + error(
> +"leaf %llu slot %u pointer invalid, offset %u size %u leaf data limit %u",
> + btrfs_header_bytenr(eb), i,
> + btrfs_item_offset_nr(eb, i),
> + btrfs_item_size_nr(eb, i), leaf_data_size);
> + error("skip remaining slots");
> + break;
> + }
> item = btrfs_item_nr(i);
> item_size = btrfs_item_size(eb, item);
> /* Untyped extraction of slot from btrfs_item_ptr */
>
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