• Qu Wenruo's avatar
    btrfs: Validate child tree block's level and first key · 581c1760
    Qu Wenruo authored
    We have several reports about node pointer points to incorrect child
    tree blocks, which could have even wrong owner and level but still with
    valid generation and checksum.
    
    Although btrfs check could handle it and print error message like:
    leaf parent key incorrect 60670574592
    
    Kernel doesn't have enough check on this type of corruption correctly.
    At least add such check to read_tree_block() and btrfs_read_buffer(),
    where we need two new parameters @level and @first_key to verify the
    child tree block.
    
    The new @level check is mandatory and all call sites are already
    modified to extract expected level from its call chain.
    
    While @first_key is optional, the following call sites are skipping such
    check:
    1) Root node/leaf
       As ROOT_ITEM doesn't contain the first key, skip @first_key check.
    2) Direct backref
       Only parent bytenr and level is known and we need to resolve the key
       all by ourselves, skip @first_key check.
    
    Another note of this verification is, it needs extra info from nodeptr
    or ROOT_ITEM, so it can't fit into current tree-checker framework, which
    is limited to node/leaf boundary.
    Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
    Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
    581c1760
backref.c 59.8 KB