I read that some bug in older 2.6.17 kernel existed (still exists?) which caused a corruption of an xfs filesystem. BTW, the strange thing is that as soon as I upgraded the kernel, error messages begin to appear! smart says the disk shows no problem.
I would like to run xfs_repair but I can't mount this disk on another machine. Furthermore, I tried remounting / read only (with mount -r -o remount /) but xfs_repair still reports the fs as mounted and writable. I temporarily linked mtab to /proc/mounts but this did not resolve xfs_repair issue...
I start cursing the day I chose xfs...