Btrfs: keep track of the extents original block length

If we've written to a prealloc extent we need to know the original block len
for the extent.  We can't figure this out currently since ->block_len is
just set to the extent length.  So introduce ->orig_block_len so that we
know how many bytes were in the original extent for proper extent logging
that future patches will need.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 679225555f7..99a0dcb5ba2 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -24,6 +24,7 @@ struct extent_map {
 	u64 mod_start;
 	u64 mod_len;
 	u64 orig_start;
+	u64 orig_block_len;
 	u64 block_start;
 	u64 block_len;
 	u64 generation;