I have been struggling with a problem for about two weeks, and finally solved it this morning. The problem was with Logical Volume Management under Red Hat Enterprise Linux, version 4. Logical Volume Management (LVM) allows sysads to dynamically resize Linux file systems, in similar manner to the way that Partition Magic allows Windows uses to resize partitions. The principal difference is that LVM can resize a live file system
on the fly. This mean no outage, and uptime is a good thing.
Unfortunately, one of my production systems
TvFerret 
was running out of space in /home. When I attempted to grow the file system, it would refuse, complaining about an
unable to resize or
no space left on device. The error messages would also reference
ioctl.
Turns out, I had applied a few updates, including a patch to LVM. The patch did not tell me, however that it required the rev-level 34 kernel. As I had not booted the system since last year, it was still running on rev-level 5. I held my breath, issued a remote reboot, and waited. A moment later, my phone signaled that the boot was complete. I logged in and resize the file system without error.