Fsyncers and curveballs (the Firefox 3 fsync() problem)

If you think 'echo "text" >> file' cannot corrupt data before the place you're writing to,
when power is lost at the wrong moment (e.g. laptop runs out of battery), think again.  There
are filesystems and filesystem options that will prevent that, but ext3 with default options
isn't one of them.  Not just theoretically: I have actually seen such corruption in log files.