On 2019/2/20 下午7:11, fdman...@kernel.org wrote:
> From: Filipe Manana <fdman...@suse.com>
>
> At ctree.c:key_search(), the assertion that verifies the first key on a
> child extent buffer corresponds to the key at a specific slot in the
> parent has a disadvantage: we effectively hit a BUG_ON() which requires
> rebooting the machine later. It also does not tell any information about
> which extent buffer is affected, from which root, the expected and found
> keys, etc.
>
> However as of commit 581c1760415c48 ("btrfs: Validate child tree block's
> level and first key"), that assertion is not needed since at the time we
> read an extent buffer from disk we validate that its first key matches the
> key, at the respective slot, in the parent extent buffer. Therefore just
> remove the assertion at key_search().
>
> Signed-off-by: Filipe Manana <fdman...@suse.com>
Reviewed-by: Qu Wenruo <w...@suse.com>
Thanks,
Qu
> ---
> fs/btrfs/ctree.c | 21 ---------------------
> 1 file changed, 21 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 5b9f602fb9e2..e754bd019618 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2529,26 +2529,6 @@ setup_nodes_for_search(struct btrfs_trans_handle
> *trans,
> return ret;
> }
>
> -static void key_search_validate(struct extent_buffer *b,
> - const struct btrfs_key *key,
> - int level)
> -{
> -#ifdef CONFIG_BTRFS_ASSERT
> - struct btrfs_disk_key disk_key;
> -
> - btrfs_cpu_key_to_disk(&disk_key, key);
> -
> - if (level == 0)
> - ASSERT(!memcmp_extent_buffer(b, &disk_key,
> - offsetof(struct btrfs_leaf, items[0].key),
> - sizeof(disk_key)));
> - else
> - ASSERT(!memcmp_extent_buffer(b, &disk_key,
> - offsetof(struct btrfs_node, ptrs[0].key),
> - sizeof(disk_key)));
> -#endif
> -}
> -
> static int key_search(struct extent_buffer *b, const struct btrfs_key *key,
> int level, int *prev_cmp, int *slot)
> {
> @@ -2557,7 +2537,6 @@ static int key_search(struct extent_buffer *b, const
> struct btrfs_key *key,
> return *prev_cmp;
> }
>
> - key_search_validate(b, key, level);
> *slot = 0;
>
> return 0;
>
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