I just installed a F7 system, using LVM (via kickstart). I have named the volume group "winwall" (the system name), and have two volumes named "usr" (for /usr) and "usrlocal" (for /usr/local). Anaconda wrote /etc/fstab with usrlocal before usr, and so /usr/local is mounted first on boot. This confuses something, apparently in the kernel. "df /usr/local" and "fuser -muv /usr/local" show results for /usr instead. When I strace, it appears that the kernel is where the problem is. In df, statfs64("/usr/local/",...) returns the size, space available, etc. for /usr. In fuser, stat64("/usr/local/",...) returns the device major/minor and the inode of the /usr/local directory in the /usr filesystem. If I unmount /usr/local and remount it (so it appears after /usr in /proc/mounts and such), I don't see this behavior. The statfs64() and stat64() calls return the info about the /usr/local filesystem when they get to it, not /usr. My guess would be that something is doing a substring match on the device name instead of a full string match.
How can /usr/local get mounted first? There's nowhere to mount /usr/local until /usr gets mounted...
Sorry, no kernel bug here - all anaconda bug. Anaconda created and mounted /usr/local before /usr during install (the root filesystem has a /usr/local directory so the mount succeeds, but then the /usr mount covers it up).