linux readahead bug is back

[D. Hugh Redelmeier]

| From andre at bwh.harvard.edu Fri Nov 23 00:33:13 2007

|  My father just bought a F8 DVD, but it failed the mediacheck.  It 
| turns out that the vendor failed to apply zero-padding to the ISO file
| before burning, and that the failure occurs about 40 KB before the end of
| the disc, presumably due to the readahead bug having returned.  This had
| been fixed when F7 was released, but apparently is back now in both the
| updated F7 and F8 kernels.  Anyone know when this regression happened, and
| if there are plans to fix it?

My theory, based on a few samples, is that the "readahead bug" was
never fixed.  It only manifests itself on some drives.  Older drives,
I think.

I've never had trouble actually installing from a disc+drive because
of the readahead bug.  (But a mediacheck will fail.)

The only time that I've experienced the problem is when trying to
access the whole raw contents of the disk.  The only important reasons
to do so are for integrity checking or duplicating.  Perhaps you can do
those on another drive.