linux-wandboard

btrfs: Fix typo in free-space-cache.c

Correct spelling "cace" to "cache" in
fs/btrfs/free-space-cache.c

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>