tree 8f0e073af940b1bdfb134b945a03a1b43b614352
parent e9061e214810c9534381a705a1b46533e09f2676
author Chris Mason <chris.mason@oracle.com> 1255102193 -0400
committer Chris Mason <chris.mason@oracle.com> 1255102193 -0400

Btrfs: fix file clone ioctl for bookend extents

The file clone ioctl was incorrectly taking the offset into the
extent on disk into account when calculating the length of the
cloned extent.

The length never changes based on the offset into the physical extent.

Test case:

fallocate -l 1g image
mke2fs image
bcp image image2
e2fsck -f image2

(errors on image2)

The math bug ends up wrapping the length of the extent, and things
go wrong from there.

Signed-off-by: Chris Mason <chris.mason@oracle.com>