tree 4e2e716400cc45a6697475629f4c046b96ff76e7
parent e4404d6e8da678d852b7f767f665f8edf76c9e9f
author Yan Zheng <zheng.yan@oracle.com> 1229094218 -0500
committer Chris Mason <chris.mason@oracle.com> 1229094218 -0500

Btrfs: fix nodatasum handling in balancing code

Checksums on data can be disabled by mount option, so it's
possible some data extents don't have checksums or have
invalid checksums. This causes trouble for data relocation.
This patch contains following things to make data relocation
work.

1) make nodatasum/nodatacow mount option only affects new
files. Checksums and COW on data are only controlled by the
inode flags.

2) check the existence of checksum in the nodatacow checker.
If checksums exist, force COW the data extent. This ensure that
checksum for a given block is either valid or does not exist.

3) update data relocation code to properly handle the case
of checksum missing.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>