Commits
Li Zefan committed ec9ef7a13be
Btrfs: simplfy calculation of stripe length for discard operation
For btrfs raid, while discarding a range of space, we'll need to know
the start offset and length to discard for each device, and it's done
in btrfs_map_block().
However the calculation is a bit complex for raid0 and raid10, so I
reimplement it based on a fact that:
dev1 dev2 dev3 (raid0)
-----------------------------------
s0 s3 s6 s1 s4 s7 s2 s5
Each device has (total_stripes / nr_dev) stripes, or plus one.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>