When my backup system attempts to create an LVM snapshot of an ext4 fs, it fails, and the log is full of kernel warnings. Some of my servers actually reboot themselves. i've had to turn off backups for the moment.
It seems that this is a known problem, and a patch for it already exists. See: Re: warning in ext4_journal_start_sb on filesystem freeze (Linux Ext4)
I gave this info to a receptionist at Oracle on 12/30, and she seemed to understand that it needed to get to the Oracle Linux product group, but so far no one has contacted me for details, or to let me know that they're working on this.
It seems to me that this is a 100% critical bug, that *ought* to have gotten an immediate reaction. Does anyone here know how to get Oracle's attention?