Btrfs: Maintain a list of inodes that are delalloc and a way to wait on them

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

diff --cc fs/btrfs/btrfs_inode.h
Simple merge

diff --cc fs/btrfs/ctree.h
Simple merge

diff --cc fs/btrfs/disk-io.c
Simple merge

diff --cc fs/btrfs/extent-tree.c
Simple merge

diff --cc fs/btrfs/file.c
Simple merge

diff --cc fs/btrfs/inode.c
Simple merge

diff --cc fs/btrfs/ioctl.c
Simple merge