Re: [PATCH] Btrfs: relocate csums properly with prealloc extents

[Johannes Hirte <johannes.hirte@datenkhaos.de>]

On Fri, 27 Sep 2013 09:37:00 -0400
Josef Bacik <jbacik@fusionio.com> wrote:

> A user reported a problem where they were getting csum errors when
> running a balance and running systemd's journal.  This is because
> systemd is awesome and fallocate()'s its log space and writes into
> it.  Unfortunately we assume that when we read in all the csums for
> an extent that they are sequential starting at the bytenr we care
> about.  This obviously isn't the case for prealloc extents, where we
> could have written to the middle of the prealloc extent only, which
> means the csum would be for the bytenr in the middle of our range and
> not the front of our range.  Fix this by offsetting the new bytenr we
> are logging to based on the original bytenr the csum was for.  With
> this patch I no longer see the csum errors I was seeing.  Thanks,

Any assessment when this goes upstream? Until it hit Linus tree it
won't won't appear in stable. And this seems rather important.