Determining Specific File Responsible for High I/O

This is a simple problem but the first time I've ever had to actually fix it: finding which specific files/inodes are the targets of the most I/O. I'd like to be able to get a general system overview, but if I have to give a PID or TID I'm alright with that. I'd like to go without having to do a strace on the program that pops up in iotop. Preferably, using a tool in the same vein as iotop but one that itemizes by file. I can use lsof to see which files mailman has open but it doesn't indicate which file is receiving I/O or how much. I've seen elsewhere where it was suggested to use auditd but I'd prefer to not do that since it would put the information into our audit files, which we use for other purposes and this seems like an issue I ought to be able to research in this way. The specific problem I have right now is with LVM snapshots filling too rapidly. I've since resolved the problem but would like to have been able to fix it this way rather than just doing an ls on all the open file descriptors in /proc//fd to see which one was growing fastest.