tree f7b1cbec89d9c6d030f15817e77ee42e5941244a
parent 46b665ceb1edd2ac149ff701313c115f52dc0348
author Jan Schmidt <list.btrfs@jan-o-sch.net> 1366905891 +0000
committer Josef Bacik <jbacik@fusionio.com> 1367870119 -0400

Btrfs: rescan for qgroups

If qgroup tracking is out of sync, a rescan operation can be started. It
iterates the complete extent tree and recalculates all qgroup tracking data.
This is an expensive operation and should not be used unless required.

A filesystem under rescan can still be umounted. The rescan continues on the
next mount.  Status information is provided with a separate ioctl while a
rescan operation is in progress.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>