System Administration Guide: Devices and File Systems

Bad Block Number Checks

The fsck command checks each block number claimed by an inode to determine whether its value is higher than the value of the first data block and lower than that of the last data block in the file system. If the block number is outside this range, it is considered a bad block number.

Bad block numbers in an inode might be caused by an indirect block not being written to the file system. The fsck command prompts you to clear the inode.