[Pkg-utopia-maintainers] Bug#569058: btrfs issues

[Alexander Kurtz]

Hi,

I also experienced this issue with dbus and btrfs and fixed it by simply
reinstalling the dbus package.

I also think it's not the first time this happens: I've had a few
experiences where different error messages lead me to reinstalling a
package, which fixed that particular problem.

From my experience this happens particularly in situations where the
btrfs file system is under heavy load (this doesn't mean much data is
read/written, but that there are are *lots* of open files which are
read/written to simultaneously) like upgrading a lot of packages with
dpkg.

I _guess_ that something roughly like that happens:
 * dpkg does a lot of small file modifications
   (creating, changing perms, etc.)
 * btrfs caches these transactions
 * other file modifications happen
 * the original dpkg transactions are delayed over and over again
 * the machine is rebooted and the cache is lost

However just guessing without having looked at the code.

So for provoking this bug I would:
 * create/remove lots of small files
 * change their permissions and possibly content
 * maybe do a snapshot
 * repeat the whole procedure

Best Regards

Alexander Kurtz
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